| 1. |
- Baskin, CC, et al.
(författare)
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Seed dormancy-breaking and germination requirements of Drosera anglica, an insectivorous species of the Northern Hemisphere
- 2001
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Ingår i: Acta Oecologica. - 1146-609X .- 1873-6238. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- Seeds of Drosera anglica collected in Sweden were dormant at maturity in late summer, and dormancy break occurred during cold stratification. Stratified seeds required light for germination, but light had to be given after temperatures were high enough to be favorable for germination. Seeds stratified in darkness at 5/1 ░C and incubated in light at 12/12 h daily temperature regimes of 15/6, 20/10 and 25/15 ░C germinated slower and to a significantly lower percentage at each temperature regime than those stratified in light and incubated in light. Length of the stratification period required before seeds would germinate to high percentages depended on (1) whether seeds were in light or in darkness during stratification and during the subsequent incubation period, and (2) the temperature regime during incubation. Seeds collected in 1999 germinated to 4, 24 and 92 % in light at 15/6, 20/10 and 25/15 ░C, respectively, after 2 weeks of stratification in light. Seeds stratified in light for 18 weeks and incubated in light at 15/6, 20/10 and 25/15 ░C germinated to 87, 95 and 100 %, respectively, while those stratified in darkness for 18 weeks and incubated in light germinated to 6, 82 and 91 %, respectively. Seeds collected from the same site in 1998 and 1999, stratified in light at 5/1 ░C and incubated in light at 15/6 ░C germinated to 22 and 87 %, respectively, indicating year-to-year variation in degree of dormancy. As dormancy break occurred, the minimum temperature for germination decreased. Thus, seed dormancy is broken in nature by cold stratification during winter, and by spring, seeds are capable of germinating at low habitat temperatures, if they are exposed to light. ⌐ 2001 ╔ditions scientifiques et mΘdicales Elsevier SAS.
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| 2. |
- Berg, Henrik
(författare)
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Differential seed dispersal in Oxalis acetosella, a cleistogamous perennial herb
- 2000
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Ingår i: Acta Oecologica. - 1146-609X .- 1873-6238. ; 21:2, s. 109-118
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Tidskriftsartikel (refereegranskat)abstract
- Explosive seed dispersal in the cleistogamous perennial forest herb Oxalis acetosella was studied during two growing seasons, to determine whether seeds derived from chasmogamous (CH) and cleistogamous (CL) flowers differ in dispersal distance. Seed dispersal distance, seed weight, and height of fruits were measured for both flower types, and the effects of phenology and year were also taken into account. The dispersal experiment was performed indoors, using plants transplanted from natural populations to pots. CL seeds were thrown significantly further than were CH seeds, though there was a considerable overlap in dispersal distances. There was also a significant positive relationship between seed weight and dispersal distance. No relationship was found between fruit height and dispersal distance. The results of this study contradict the common view that CL progeny should always be dispersed closer to the mother plant than CH progeny. The ecological implications of the dispersal difference are unclear, especially since it is uncertain whether CH seeds are generally outcrossed or not. Variation in dispersal distance in O. acetosella seems to be mainly dependent on a combination of reproductive mode and variation in seed weight.
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| 3. |
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| 4. |
- Acharya, Kamal Prasad, et al.
(författare)
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Latitudinal variation of life-history traits of an exotic and a native impatiens species in Europe
- 2017
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 81, s. 40-47
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the responses of invasive and native populations to environmental change is crucial for reliable predictions of invasions in the face of global change. While comparisons of responses across invasive species with different life histories have been performed before, comparing functional traits of congeneric native and invasive species may help to reveal driving factors associated with invasion. Here we compared morphological functional trait patterns of an invasive species (Impatiens parviflora) with its congeneric native species (I. noli-tangere) along an approximately 1600 km European latitudinal gradient from France (49 degrees 34'N) to Norway (63 degrees 40'N). Soil nitrogen was recorded during six weeks of the growing season, and light, soil moisture, and nutrient availability were estimated for each sampled population using community weighted means of indicator values for co-occurring species. Temperature data were gathered from nearby weather stations. Both the native and invasive species are taller at higher latitudes and this response is strongest in the invasive species. Seed mass and number of seeds per capsule increase in I. noli-tangere but decrease in I. parviflora towards higher latitudes. Surprisingly, plant height in the invasive I. parviflora decreases with increasing soil nitrogen availability. The latitudinal pattern in seed mass is positively related to temperature in I. noli-tangere and negatively in I. parviflora. Leaf area of both species decreases with increasing Ellenberg indicator values for nitrogen and light but increases with increasing soil moisture. Soil nitrogen concentrations and Ellenberg indicator values for nitrogen have significant positive (I. nolitangere) and negative (I. parviflora) effects on the number of seeds per capsule. Our results show that the native I. noli-tangere has efficient reproduction at its range edge while the invasive I. parviflora shows a marked decrease in seed size and seed number per capsule. These patterns are unrelated to the growth and obtained size of the plants: even low soil nitrogen availability in the north seemed not to limit plant growth and size. Our results suggest that the invasive I. parviflora tends to become more invasive at lower latitudes by producing heavier seeds and more seeds per capsule.
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| 5. |
- Bienau, Miriam J., et al.
(författare)
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Synchronous flowering despite differences in snowmelt timing among habitats of Empetrum hermaphroditum
- 2015
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 69, s. 129-136
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Tidskriftsartikel (refereegranskat)abstract
- The topography within arctic-alpine landscapes is very heterogeneous, resulting in diverse snow distribution patterns, with different snowmelt timing in spring. This may influence the phenological development of arctic and alpine plant species and asynchronous flowering may promote adaptation of plants to their local environments. We studied how flowering phenology of the dominant dwarf shrub Empetrum hermaphroditum varied among three habitats (exposed ridges, sheltered depressions and birch forest) differing in winter snow depth and thus snowmelt timing in spring, and whether the observed patterns were consistent across three different study areas. Despite significant differences in snowmelt timing between habitats, full flowering of E. hermaphroditum was nearly synchronous between the habitats, and implies a high flowering overlap. Our data show that exposed ridges, which had a long lag phase between snowmelt and flowering, experienced different temperature and light conditions than the two late melting habitats between snowmelt and flowering. Our study demonstrates that small scale variation seems matter less to flowering of Empetrum than interannual differences in snowmelt timing.
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| 6. |
- Blixt, Torbjörn, et al.
(författare)
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Clear-cuts in production forests: From matrix to neo-habitat forbutterflies
- 2015
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Ingår i: Acta Oecologica. - : Elsevier. - 1146-609X .- 1873-6238. ; 69, s. 71-77
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Tidskriftsartikel (refereegranskat)abstract
- Butterfly conservation in Europe is mainly focused on well-defined grassland habitat patches. Such anapproach ignores the impact of the surrounding landscape, which may contain complementary resourcesand facilitate dispersal. Here, we investigated butterfly species richness and abundance in a habitatnormally regarded as unsuitable matrix: production forestry clear-cuts. Butterflies were recorded in 48clear-cuts in southern Sweden differing with regards to the time since clear-cutting and land-use history(meadow or forest based on historical maps from the 1870s). All clear-cuts had been managed as productionforests for at least 80e120 years. A total of 39 species were found in clear-cuts of both land-usehistories, but clear-cuts with a history as meadow had on average 34% higher species richness and 19%higher abundance than did clear-cuts with a history as forest. No effect of the time since clear-cuttingwas found, irrespective of land-use history, which was likely due to the narrow timespan sampled (<8years). The absence of temporal effect suggests that clear-cuts may provide butterflies with valuableresources for 10e15 years. Assuming a 100 year forest rotational cycle, this means that 10e15% of thetotal forested area are made up by clear-cuts valuable to butterflies, which corresponds to an area aboutfour times as large as that of species-rich semi-natural grasslands. The study illustrates the importance ofconsidering land-use legacies in ecological research and question the landscape-ecological view thatclear-cuts make up an unsuitable matrix for butterflies. Moreover, forest conservation management withspecial attention to land-use history may increase the quality of the landscape, thus facilitating butterflymetapopulation persistence. Given their large area and assets of nectar and host plant resources, clearcutsmust be considered as a butterfly habitat in its own right. Being a man-made environment withshort history, we might call it a neo-habitat.
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| 7. |
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| 8. |
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| 9. |
- Haussmann, Natalie, et al.
(författare)
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Contrasting nurse plants and nurse rocks The spatial distribution of seedlings of two sub-Antarctic species : The spatial distribution of seedlings of two sub-Antarctic species
- 2010
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 36:3, s. 299-305
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Tidskriftsartikel (refereegranskat)abstract
- Positive plant interactions, such as those associated with nurse plants, have been suggested to dominate over negative interactions in environments with high abiotic stress. Here we demonstrate that the sub-Antarctic cushion plant species, Azorella selago (Apiaceae), positively affects the distribution of both its own seedlings and those of the perennial grass, Agrostis magellanica (Poaceae). As a result of the light weight and small size of seeds of both species, coupled with strong winds experienced in the study area, we consider it unlikely that these patterns are the result of very localized seed dispersal from the study cushions themselves. Instead, we suggest that both cushions and rocks act as seed traps, trapping seeds dispersed by wind, runoff and/or downslope sediment transport through frost creep. In addition, increased A. selago seedling numbers around cushions, but not around rocks, suggest that cushions provide a biological nurse effect, such as improving soil nutrient status or providing mychorrizae, to seedlings of their own kind.
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| 10. |
- Hedberg, H. Roberta, et al.
(författare)
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A new player in the Panamanian fig tree – fig wasp mutualism : a study on the effect of gall midges on Ficus citrifolia
- 2024
-
Ingår i: Acta Oecologica. - : Elsevier. - 1146-609X .- 1873-6238. ; 122
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Tidskriftsartikel (refereegranskat)abstract
- The mutualism between the fig tree and the pollinating fig wasps is a keystone interaction in tropical forests. However, many antagonistic interactions also occur in the system, taking advantage of the fig trees and the pollinator. One such example is an antagonistic gall midge (Cecidomyiidae) that develops inside figs. Gall midges inside figs have been documented in a few Ficus species around the world, but to our knowledge they have not previously been observed in Panama. In this study the newly observed Panamanian fig gall midge is documented, together with its parasitoid wasp. The fig gall midge was only found in Ficus citrifolia figs. We investigated the effect of fig gall midge presence on the number of seeds and the number of pollinating wasps (Pegoscapus tonduzi) in a fig and aimed to identify the species based on morphology and barcoding of the COI region. We found that the fig gall midge had no, or a negligible effect, on the reproduction of the fig tree - fig wasp mutualism. The fig gall midge most likely belongs to the genus Ficiomyia, close to Ficiomyia perarticulata. The parasitoid belongs to the genus Physothorax, close to Physothorax russelli. This study suggests that the potentially newly arrived fig gall midge currently has no major effect on the fig tree - fig wasp mutualism. However, should infestation rates increase, it is likely that the fig gall midge would affect the mutualism negatively as it has in other parts of the world. More studies on the fig gall midge species distributions in this region would be valuable and would connect these newly observed species to a larger community, adding yet another species to this complex but classic example of a mutualism.
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| 11. |
- Jonsson, Micael
(författare)
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Species richness effects on ecosystem functioning increase with time in an ephemeral resource system
- 2006
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Ingår i: Acta Oecologica. - : Elsevier. - 1146-609X .- 1873-6238. ; 29:1, s. 72-77
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Tidskriftsartikel (refereegranskat)abstract
- Extrapolating the results from experiments on effects of species loss to natural systems is difficult since most studies, with the exception of microbial microcosm studies, have been performed on relatively short time-scales. One problem with short-term, experimental studies is that complex interactions between species in natural systems may alter the importance of underlying mechanisms over time thus making the effects observed in the experiments representative of a transient phase. Although some evidence indicates that initial effects of species richness observed in short-term experiments may be persistent, other results suggest that effects may change over time. Using detritivorous insect larvae in freshwater mesocosms, where both facilitation and niche differentiation mechanisms were operating and where resources were gradually decreasing, I examined the effects of species richness over time. I found that the initial effect of species richness on ecosystem function was enhanced over time when systems of high and low diversity were compared. There was an overall effect of species composition on larval growth, and when analysing the growth of each species separately it was found that one species was significantly affected by species richness, one showed a marginally insignificant effect of species richness, and the third species was significantly, differently affected by species richness over time. Thus, the results show that species loss initially leading to small, negative, or even undetectable, effects on ecosystem function may increase in importance over the long-term.
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| 12. |
- Lehtilä, Kari, et al.
(författare)
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Seed size as an indicator of seed quality : a case study of Primula veris
- 2005
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 28:3, s. 207-212
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Tidskriftsartikel (refereegranskat)abstract
- Seed size is a widely accepted measure of seed quality, because many earlier studies have shown that large seeds have high seedling survival, growth and establishment. We tested whether ovule loss increases size of the remaining seeds and whether such size increase affects seedling establishment. We removed all except one flower from inflorescences of Primula veris L. (Primulaceae), a perennial hemicryptophyte herb, at a late stage of flowering. Flower removal (FR) increased seed size by 33% compared to the control plants. We then divided the seeds within each treatment to small, middle-sized and large seeds and carried out a sowing experiment in the field, Within each experimental group, seedling establishment was positively associated with seed size. However, despite size differences, seeds from the FIR and control groups had the same seedling establishment probability. Seeds from FR plants had a higher seedling emergence in May than those from control plants, but the number of seedlings alive per sowing plot in the late summer was the same in both experimental groups. Increase in seed mass after partial FR thus did not enhance seedling performance, although seed size variation due to other causes was positively correlated with seedling establishment. Further studies are needed to show whether plastic changes of seed size are usually adaptive or not.
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| 13. |
- Lindwall, Frida, et al.
(författare)
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Reindeer grazing has contrasting effect on species traits in Vaccinium vitis-idaea L. and Bistorta vivipara (L.) Gray
- 2013
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 53, s. 33-37
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Tidskriftsartikel (refereegranskat)abstract
- That reindeer grazing can have large effects on plant communities is well known, but how reindeer grazing affects plant traits and plant carbon (C) and nitrogen (N) allocation has not been studied to the same extent. This study was conducted in a sub-arctic dry heath in northern Sweden. 17-year-old reindeer exclosures were used to test whether reindeer grazing affects the C:N ratio (a plant quality index), and the delta C-13 and delta N-15 (indicators of changes in C and N dynamics) as well as the C and N content of above- and below ground parts of the evergreen dwarf shrub Vaccinium vitis-idaea L. and the perennial forb Bistorta vivipara (L) Gray. A lower C:N ratio was found in B. vivipara compared to V. vitis-idaea suggesting a higher grazing pressure on that species. We found that grazing reduced the total C content, by 26%, and increased the delta N-15, by 1 parts per thousand, in the leaves of B. vivipara, while no changes were observed in V. vitis-idaea. Fine roots of B. vivipara had higher delta C-13 (1 parts per thousand) and delta N-15 (2.5 parts per thousand) than the leaves, while such differences were not found in V. vitis-idaea. The results also highlight the importance of analysing both above- and belowground plant parts when interpreting natural variations in delta C-13 and delta N-15. (C) 2013 The Authors. Published by Elsevier Masson SAS. All rights reserved.
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| 14. |
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| 15. |
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| 16. |
- Mattsson, Elisabet, et al.
(författare)
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Are there any positive consequences of childhood cancer? : A review of the literature
- 2008
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Ingår i: Acta Oecologica. - : Informa UK Limited. - 1146-609X .- 1873-6238 .- 0284-186X .- 1651-226X. ; 47:2, s. 199-206
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Forskningsöversikt (refereegranskat)abstract
- The aim was to investigate whether there are any positive consequences of childhood cancer. Studies published 1990-2005 reporting survivors' descriptions of positive consequences of childhood cancer were identified through a search in the databases CINAHL, PsycINFO, and PubMed. According to a manifest content analysis, positive consequences were referred to three themes: life values, relations to others, and relation to self. A second search in the same databases was conducted to identify studies investigating whether survivors of childhood cancer differ from comparison groups with regard to variables assigned to these themes. In these studies, no conclusions about positive consequences with regard to the theme life values can be drawn, as only one study was identified. In addition, only a small minority of findings from comparative studies indicate that childhood cancer has any positive consequences with regard to relations to others and relation to self. A majority of the results indicate that survivors do not differ from comparison groups, whereas some findings highlight that friendship and marital status are areas of concern, and parenthood and sexuality are areas of potential concern. It is recommended that survivors of childhood cancer are followed up by a multi-professional team, focusing not only on the survivors' health status but also on relations to family, friends, and partners.
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| 17. |
- Mero, Sarah A., et al.
(författare)
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Environmental factors and non-chemical methods to suppress growth of the invasive plant Gutenbergia cordifolia
- 2023
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Ingår i: Acta Oecologica. - 1146-609X .- 1873-6238. ; 119
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Tidskriftsartikel (refereegranskat)abstract
- Little is known about preferred environmental conditions and non-chemical control of invasive Gutenbergia cordifolia. We assessed the effects of different A. annua crude extract concentrations, synthetic herbicide (glyphosate), fire regime and shade to G. cordifolia germination, shoot and root dry biomass, seedling height and leaf chlorophyll. High concentrations (75%) of A. annua crude extracts significantly reduced germination percentage of G. cordifolia by 25% (F2,4=77.2, p < 0.001), and suppressed shoot and root dry biomass (F2,4 = 80.3, p < 0.001; F2,4=46.104, p < 0.001, respectively) as well as seedling height and leaf chlorophyll (F2,4 = 12.02, p < 0.002; F2,4 = 15.9, p < 0.001), respectively. Medium temperature (60 °C) and long exposure time (5 min) significantly increased G. cordifolia germination percentage (F2,7 = 32.6, p < 0.001) while extreme temperatures (≥150 °C) at both (1 min) short and (5 min) long exposure time completely suppressed germination of G. cordifolia. Under high shade, while germination percentage was a third that of other treatments (F 2, 4 = 20.9, p = 0.008), mean germination took twice as long (F2, 4 = 17.9, p = 0.010) and shoot fresh biomass was reduced by half (F 2, 4 = 16.92, p = 0.004). Shoot and root dry biomass were reduced to more than a third under high shade, seedling height reduced to half but leaf chlorophyll content was not affected (F 2,4 = 6.3, p = 0.030; F 2,4 = 9.1, p = 0.020; F 2,4 = 18.3, p = 0.003; F 2,4 = 3.02, p = 0.120, respectively). We suggest using A. annua as a potential bio-herbicide and highlight considering fire and shade as suppressor tools to control G. cordifolia, but first include in-situ trials to assess their impacts to both native plants and animals.
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| 18. |
- Mpondo, Faith T., et al.
(författare)
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Traditional rangeland management can conserve insect pollinators in a semi-arid rangeland, northern Tanzania
- 2021
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 113
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Tidskriftsartikel (refereegranskat)abstract
- Globally, pollinators are threatened by land-use changes, including habitat degradation. East African rangelands are under pressure due to livestock population increase and overutilization, which lead to degradation of vegetation and soils. While traditional grazing management is widely used to restore vegetation, little is known how this affects insect pollinators. We investigated whether differently managed rangeland areas harbor different insect pollinator abundance, richness and diversity in Simanjiro, Tanzania. We established twelve blocks in four grazing areas under different management categories (private and communal enclosures, wet and dry season grazing lands) and used pan traps and sweep nets to collect insect pollinators. We collected a total of 1977 insects, representing 44 families and 239 species. Beetles were most frequently trapped, with 646 (33%) individuals, followed by 522 bees (26%). Pollinator abundance was twice as high in the private enclosure compared to the communal dry grazing area (χ2 = 27.63, P < 0.001). We found a strong positive correlation between floral and pollinator abundances (r = 0.68, P = 0.015) but not for pollinator species richness and diversity. Bee species abundance and diversity were also significantly higher (χ2 = 68.00, P < 0.0001) in enclosures compared to open rangelands and were significantly influenced by season (χ2 = 220.73, P < 0.0001). Apis mellifera (honey bee) and Lasioglossum of the subgenus Ipomalictus were the most abundant bee species with 107 (21%) and 105 (20%) individuals, respectively. We noticed a significant interaction between season and management on influencing bee pollinator numbers (χ2 = 19.84, P = 0.0002). We conclude that traditional rangeland management can strongly influence pollinator abundance and communities. Our study will aid in developing rangeland management strategies to promote conservation of and enhance pollinator availability in tropical rangelands.
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| 19. |
- Pasanen-Mortensen, Marianne, et al.
(författare)
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Land cover effects on mesopredator abundance in the presence and absence of apex predators
- 2015
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 67, s. 40-48
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Tidskriftsartikel (refereegranskat)abstract
- Trophic downgrading due to loss of apex consumers has been detected in many ecosystems. Loss of larger predators implies that medium-sized mesopredators rise to the status of apex predators which are limited bottom-up rather than top-down. Hence the density of medium-sized predators should be more strongly related to land cover in absence of larger predators. We investigate this hypothesis at a continental scale (Eurasia) for a medium-sized predator, the red fox Vulpes vulpes, in presence and absence of an apex predator, the Eurasian lynx Lynx lynx. We predicted that in absence of lynx, fox density should be positively associated with open land covers, as these could favour foxes due to high prey availability. Our results showed that fox abundance was independent of land cover in presence of lynx. However, in absence of lynx, fox density was positively but asymptotically related to cropland, while negatively related to grassland. Fox density was highest when cropland constituted approximately 30% of the landscape, likely reflecting an optimal composition of foraging and breeding habitat. Grassland was associated with low productivity, likely reflecting low prey availability. Thus, cropland is favourable for red fox, but only in absence of top-down limitation by lynx. We suggest that there are two ecosystem states in Eurasia, one northern where lynx is present as an apex predator, and one south-eastern where red fox assumes the apex predator position and its abundance is subsidised by anthropogenic land cover.
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| 20. |
- Ramula, Satu
(författare)
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Population dynamics of a monocarpic thistle : simulated effects of reproductive timing and grazing of flowering plants
- 2008
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 33:2, s. 231-239
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Tidskriftsartikel (refereegranskat)abstract
- In monocarpic plants, which die after flowering once, the timing of reproduction plays an important role. The optimal time for reproduction is when reproductive output and survival are maximized. This optimum may be altered by herbivores that consume reproductive plants of different sizes disproportionally. I examined plant survival, flowering probability, reproductive output and the probability of becoming grazed in relation to plant size in two populations of the short-lived monocarpic herb Cirsium palustre. Moreover, I simulated the consequences of changes in reproductive timing and grazing preference for population dynamics. Plant survival, flowering probability and reproductive output tended to increase with plant size, whereas the probability of becoming grazed was unaffected by plant size. According to the stochastic simulations, intense grazing would have been required to significantly reduce the stochastic population growth rate (log's) and therefore, the observed levels of grazing had no impact on log's in the study populations. Stochastic simulations conducted with selective grazing focusing on either early or late flowering plants and with different reproductive timings revealed that the grazing of early flowering plants had a constant effect on log lambda(s) despite the proportions of early and late flowering plants in the population, suggesting that there is no optimal time for reproduction. The grazing of late flowering plants reduced log lambda(s) with delayed reproduction, favouring reproduction early in the life cycle.
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| 21. |
- Rawat, Monika, et al.
(författare)
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Litter decomposition above the treeline in alpine regions : A mini review
- 2021
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Ingår i: Acta Oecologica. - Issy-les-Moulineaux : Elsevier. - 1146-609X .- 1873-6238. ; 113
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Forskningsöversikt (refereegranskat)abstract
- Litter decomposition is a key driver of ecosystem processes and carbon cycling. Decomposition rate is influenced by numerous factors, such as temperature, humidity, litter properties, soil properties, and properties of soil fauna/microbial communities. The aim of this review was to summarize current knowledge on litter decomposition above the treeline in alpine regions worldwide and identify: I) factors that have been studied in great detail, II) factors that have been less intensively investigated, III) geographical regions that have been less well studied, and IV) factors with consistent or inconsistent effects on decomposition. The review showed inconsistent results for all factors covered by two or more studies regarding their effect on decomposition rate (positive, negative, no effect), usually a result of interactions between factors. Studies examining one or several factors in the physical environment (i.e., altitude, experimental warming, microclimate, snow cover and soil moisture) were most common, while studies on different aspects of resource quality were the second most common. The impacts of trophic interactions on soil microbes and fauna were less frequently studied. Europe and Asia were the best-represented regions, in terms of number of studies and geographical distribution, while there were no studies from Africa and very few from South America and Australia. North American studies were all from Colorado, and those from Asia were all from China. In order to obtain better global representation, there is a need for studies in Africa, South America, and Australia. There is also a need for more studies to explain the large variation in responses of litter decomposition rates to different influencing factors in alpine environments. Future research should focus on interactions between different factors and on experiments testing specific relationships, such as the potential interaction between temperature and soil moisture and its effect on litter decomposition above the treeline in alpine regions. © 2021 The Authors
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| 22. |
- Schatz, Bertrand, et al.
(författare)
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Pollinator conservation in the context of global changes with a focus on France and Belgium
- 2021
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Ingår i: Acta Oecologica. - : Elsevier BV. - 1146-609X .- 1873-6238. ; 112
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Tidskriftsartikel (refereegranskat)abstract
- The decline of pollinators has been demonstrated scientifically and this phenomenon is widely recognized by both the general public and by stakeholders. Since pollinators face different threats that are all linked to human activities, there is a unique and unprecedented responsibility for people to conserve pollinators, requiring political action to counter the substantial worldwide risk of pollinator loss. As our perception of the situation is rapidly changing, as a result of the steady accumulation of international and national reports as well as new scientific findings, we propose here to provide an updated overview of pollinator conservation globally. We present the key messages and the proposed solutions found in international reports and assessments, how European countries have interpreted these solutions proposed in the context of existing international frameworks. Next, we analyze how scientific research is addressing the issue of pollinator conservation through different international, European and national programs. The analysis of the keywords used in published scientific articles also allows us to characterize how the scientific community has engaged with this issue over time. Finally, we focus on how France and Belgium have reacted to the observed decline of pollinators, and examine their national interpretations, conservation actions and research contributions.
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| 23. |
- van Kolfschoten, Lisette, et al.
(författare)
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Specialist fig-consuming lepidopterans can inflict costs to plant reproductive success that are mitigated by ant bodyguards
- 2024
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Ingår i: Acta Oecologica. - : Elsevier. - 1146-609X .- 1873-6238. ; 124
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Tidskriftsartikel (refereegranskat)abstract
- Insect herbivores can inflict substantial costs on plant reproductive success. Seed herbivory impacts directly by reducing the number of seeds and therefore the dispersal and reproductive potential of the plant. Fig trees, Ficus, provide keystone resources for tropical forests. The pollinating fig wasps develop inside figs, so consumption of unripe figs results in trees not only losing seeds but also their pollen dispersers. Selection to defend figs should therefore be strong. Seed herbivory is understudied in tropical forests and most data has been collected from fallen fruits. Here we use canopy sampling to identify fig-consuming larvae in central Panama and quantify both their consequences for the fig trees' reproductive success and the defensive value that ants provide against these larvae. Field surveys of 46 crops from nine fig species revealed that larvae could destroy up to 80% of figs on a tree. From seven Ficus species we barcoded (using COI) 51 individual fig consuming larvae (mainly Lepidoptera) that grouped into seven molecular operational taxonomic units. Lepidopteran larvae formed two feeding strategies, either stationary within a fig or tunneling between figs. Within the context of our study, stationary larvae were specialists whereas tunneling larvae were either specialists or generalists found on different Ficus species. Trees with ants had significantly fewer figs consumed by larvae (9% +/- 17% (mean +/- SD) for trees with azteca ants and 16% +/- 24% for trees with other ants) than did trees without ants (51% +/- 27%). Our results corroborate earlier findings that hosting ants can be an effective defensive mechanism for trees against seed herbivores or other antagonistic insects. Our study contributes to a wider body of research around the networks of insects associated with figs that highlights the importance of a multitrophic approach for understanding mutualism stability and persistence in the face of antagonism.
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| 24. |
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| 25. |
- Watz, Johan, 1977-, et al.
(författare)
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Effects of fragmentation per se on slug movement
- 2021
-
Ingår i: Acta Oecologica. - : Elsevier. - 1146-609X .- 1873-6238. ; 112
-
Tidskriftsartikel (refereegranskat)abstract
- To predict the effects of habitat alterations on animal populations we need insight into how the habitat configuration influences local scale movements. This relationship may be particularly important for effective management of pest species. We tracked 80 PIT-tagged Spanish slugs (Arion vulgaris) in 16 × 16 m arenas with manipulated habitat fragmentation. The arenas had habitat patches consisting of high grass residing within a matrix of short grass, and the arenas with a high degree of fragmentation had 12 large (2 × 2 m), 13 medium-sized (1 × 1 m) and 12 small (0.5 × 0.5 m) patches, whereas the arenas with low fragmentation had four 4 × 4 m patches, resulting in equal amounts of total habitat patch area in the two treatments. The measured mean distance moved per day was 3.8 m, and between 0 and 25% of the slugs left the arenas each day. Fragmentation treatment had no effect on these two measurements. In the treatment with patches of different sizes, slugs distributed themselves among the patch size classes according to the total amount of habitat area for each habitat patch class, whereas patch edge did not explain the distribution pattern. All in all, fragmentation per se seems to play a minor role in the local movement and distribution of Spanish slugs.
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| 26. |
- Westerberg, Lars, et al.
(författare)
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Spatial pattern of occurrence of epiphytic lichens on oaks in a heterogeneous landscape
- 2017
-
Ingår i: Acta Oecologica. - : ELSEVIER SCIENCE BV. - 1146-609X .- 1873-6238. ; 84, s. 64-71
-
Tidskriftsartikel (refereegranskat)abstract
- Quercus robur (oaks) provides an important substrate for many epiphytic lichens, and with increasing age the bark becomes suitable for some rare species. These species may respond to environmental and landscape factors differently, and at different spatial scales. We tested the effect of factors related to the individual tree and the surrounding landscape on the occurrence and richness patterns of lichens species. The study system consisted of 213 oaks selected in a grid system within a 400 km(2) heterogeneous oak-rich area in south-eastern Sweden. Oaks had been selected to be relatively uniform in size (circumference 3.1-4.1 m), and as uniformly distributed as possible in the study area. Landscape factors were calculated for various spatial scales (circles with radius ranging from 28 to 1225 m from a studied oak). One of the landscape factors stands out as of general importance oak density in the surrounding while the others (amount of forest, water, houses and arable field) had no effects, or weak effects on only some species. Among the tree specific variables, circumference was consistently important (despite ranging from only 3.1-4.1 m) while inconsistent effects were seen by sun exposure of oak trunk (Chaenotheca phaeocephala, Ramalina baltica) and density of shrubs and trees near the tree (Ch. phaeocephala). The occurrence patterns of Cliostomum corrugatum, Ch. phaeocephala, R. baltica and richness (number of eleven target lichens) were best explained by the density of oaks within radii of 401, 199, 199 and 303 m, respectively. In conclusion, our study highlighted the importance of spatial scale for understanding the occurrence of epiphytic lichens and suggests spatial scales and oak densities that could be targeted for landscape and conservation planning. (C) 2017 Elsevier Masson SAS. All rights reserved.
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| 27. |
- Bruun, Hans Henrik, et al.
(författare)
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Exudation of low molecular weight organic acids by germinating seeds of two edaphic ecotypes of Silene nutans L.
- 2001
-
Ingår i: Acta Oecologica. - 1146-609X. ; 22:5-6, s. 285-291
-
Tidskriftsartikel (refereegranskat)abstract
- Two parapatric ecotypes of Silene nutans, exhibiting distinct allozyme patterns, morphology and autecology were investigated for differences in exudation of low molecular weight organic acids from germinating seeds, and for differences in seed phosphorus content. The calcicolous ecotype is restricted to calcareous soils, and the silicicolous one predominantly occurs on acid soils, and sometimes, although less frequently, on neutral to alkaline soils. No clear difference was found between ecotypes. However, within the silicicolous ecotype seed samples showed marked differences in exudation pattern and seed phosphorus content depending on origin along the soil acidity gradient. Seeds of low-pH origin exuded more dicarboxylic acids (malic + succinic acid, oxalic acid) and had a lower phosphorus content than seeds of high pH origin. The exudation of dicarboxylic acids from seeds of low pH origin is probably an adaptation to adverse conditions (aluminium toxicity) on acid soils. The pattern is similar to that found among different cultivars of wheat. It is contrasted to the pattern found on comparison of a suite of calcifugous and calcicolous species, where exudation of di- and tricarboxylic acids is associated with solubilisation of recalcitrantly bound phosphorus and iron in calcareous soils. (C) 2001 Editions scientifiques et medicales Elsevier SAS.
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| 28. |
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| 29. |
- Olsson, Mikael
(författare)
-
A new test method for measuring the galling resistance between metal powders and die tool materials in powder compaction
- 2011
-
Ingår i: Wear. - Amsterdam : Elsevier. - 0043-1648 .- 1873-2577. ; 273:1, s. 49-54
-
Tidskriftsartikel (refereegranskat)abstract
- The friction characteristics and galling resistance between metal powder and die tool material in metal powder compaction is of outmost importance since they will influence the porosity and surface quality of the green body and consequently the porosity, tolerances and surface quality of the final sintered product. In the present study, a new test method for evaluating the tribological performance of die tool materials aimed for powder compaction is presented. The test method is based on controlled scratch testing using a commercial scratch tester but instead of the commonly used Rockwell C diamond stylus a sample holder with a small green body of compacted powder particles is drawn over the surface in a well controlled multi pass linear reciprocating sliding contact. The capability of the test method was evaluated for different types of tool materials including two PVD coatings in contact with different types of metal powders to determine the friction characteristics and the adhesion and material transfer tendency at the sliding interface. Post-test examination of the tool surfaces using FEG-SEM and EDS were performed in order to evaluate the mechanisms controlling the friction behavior and the material transfer tendency. The results show that the proposed test is a simple and fast method to obtain relevant data regarding the friction and galling characteristics of die tool materials in metal powder compaction. The mechanisms prevailing at the green body/die tool material interface, e.g. cold welding, can easily be monitored by the friction and acoustic emission signals. Of the die tool materials investigated the low friction PVD a-C:Cr coating displayed the lowest friction and highest galling resistance.
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| 30. |
- Alarcon, Sonia, et al.
(författare)
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Endocrine, metabolic and apical effects of in utero and lactational exposure to non-dioxin-like 2,2 ',3,4,4 ',5,5 '-heptachlorobiphenyl (PCB 180) : A postnatal follow-up study in rats
- 2021
-
Ingår i: Reproductive Toxicology. - : Elsevier. - 0890-6238 .- 1873-1708. ; 102, s. 109-127
-
Tidskriftsartikel (refereegranskat)abstract
- PCB 180 is a persistent and abundant non-dioxin-like PCB (NDL-PCB). We determined the developmental toxicity profile of ultrapure PCB 180 in developing offspring following in utero and lactational exposure with the focus on endocrine, metabolic and retinoid system alterations. Pregnant rats were given total doses of 0, 10, 30, 100, 300 or 1000 mg PCB 180/kg bw on gestational days 7-10 by oral gavage, and the offspring were sampled on postnatal days (PND) 7, 35 and 84. Decreased serum testosterone and triiodothyronine concentrations on PND 84, altered liver retinoid levels, increased liver weights and induced 7-pentoxyresorufin O-dealkylase (PROD) activity were the sensitive effects used for margin of exposure (MoE) calculations. Liver weights were increased together with induction of the metabolizing enzymes cytochrome P450 (CYP) 2B1, CYP3A1, and CYP1A1. Less sensitive effects included decreased serum estradiol and increased luteinizing hormone levels in females, decreased prostate and seminal vesicle weight and increased pituitary weight in males, increased cortical bone area and thickness of tibial diaphysis in females and decreased cortical bone mineral density in males. Developmental toxicity profiles were partly different in male and female offspring, males being more sensitive to increased liver weight, PROD induction and decreased thyroxine concentrations. MoE assessment indicated that the 95th percentile of current maternal PCB 180 concentrations do not exceed the estimated tolerable human lipid-based PCB 180 concentration. Although PCB 180 is much less potent than dioxin-like compounds, it shares several toxicological targets suggesting a potential for interactions.
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| 31. |
- Andreucci, Alessandro, et al.
(författare)
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Cadmium may impair prostate function as measured by Prostate Specific Antigen in semen: a cross-sectional study among European and Inuit men.
- 2015
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 1873-1708 .- 0890-6238. ; 53:Feb 3, s. 33-38
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated the association between cadmium in blood and the concentration of the prostate specific antigen (PSA) in semen, including the modifying effects of zinc or the CAG polymorphism in the androgen receptor (AR). Blood and semen samples were collected from 504 partners of pregnant women in Greenland, Poland and Ukraine. We found an inverse trend between cadmium and PSA (log (ß)= -0.121, 95% Confidence Interval (CI):-0.213; -0.029, P=0.0103) in Greenlandic men. Similar results were observed in men with a high number of CAG repeats (CAG 24) (log (ß)=-0.231, 95% CI:-0.363; -0.098, P=0.0009). Inverse trends between cadmium and PSA were found when semen zinc concentrations were below the median value for men from Ukraine and Greenland. These outcomes suggest that cadmium may impair prostate function, as measured by PSA in semen, while high zinc levels and a low number of CAG repeats protects against this action.
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| 32. |
- Baburamani, Ana A, et al.
(författare)
-
Microglia toxicity in preterm brain injury
- 2014
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 48, s. 106-112
-
Tidskriftsartikel (refereegranskat)abstract
- Microglia are the resident phagocytic cells of the central nervous system. During brain development they are also imperative for apoptosis of excessive neurons, synaptic pruning, phagocytosis of debris and maintaining brain homeostasis. Brain damage results in a fast and dynamic microglia reaction, which can influence the extent and distribution of subsequent neuronal dysfunction. As a consequence, microglia responses can promote tissue protection and repair following brain injury, or become detrimental for the tissue integrity and functionality. In this review, we will describe microglia responses in the human developing brain in association with injury, with particular focus on the preterm infant. We also explore microglia responses and mechanisms of microglia toxicity in animal models of preterm white matter injury and in vitro primary microglia cell culture experiments. © 2014 The Authors.
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| 33. |
- Bereketoglu, Ceyhun, et al.
(författare)
-
The brominated flame retardants TBECH and DPTE alter prostate growth, histology and gene expression patterns in the mouse
- 2021
-
Ingår i: Reproductive Toxicology. - : Elsevier. - 0890-6238 .- 1873-1708. ; 102, s. 43-55
-
Tidskriftsartikel (refereegranskat)abstract
- The brominated flame retardants (BFRs), 1,2-dibromo-4-(1,2 dibromoethyl)cyclohexane (TBECH) and 2,3-dibromopropyl-2,4,6-tribromophenyl ether (DPTE) bind to the androgen receptor (AR). In vitro bioassays have shown that TBECH is a potent androgen agonist while DPTE is a potent AR antagonist. Both TBECH and DPTE alter gene expression associated with AR regulation. However, it remains to be determined if TBECH and DPTE can affect the prostate. For this reason, we exposed CD1 mice to a 1:1 mixture of TBECH diastereomers α and β, a 1:1 mixture of γ and δ, and to DPTE, and tested their effects on prostate growth, histology and gene expression profiles. Castrated (C) mice were used to study the androgenic effects of TBECHαβ and TBECHγδ while the antagonistic effects of DPTE were studied in non-castrated (NC) mice. We observed that testosterone and TBECHγδ increased body and prostate weights while TBECHαβ affected neither of them; and that DPTE had no effect on body weight but reduced prostate weight drastically. Histomorphometric analysis of the prostate revealed epithelial and glandular alterations in the TBECHγδ group comparable to those in testosterone group while alterations in the TBECHαβ group were less pronounced. DPTE displayed androgen antagonist activity reminiscent of castration. The transcription profile of the prostate was altered by castration and exposure to testosterone and to TBECHγδ reversed several of these changes. Testosterone and TBECHγδ also regulated the expression of several androgen responsive genes implicated in prostate growth and cancer. While DPTE resulted in a drastic reduction in prostate weight, it only affected a small number of genes. The results indicate that TBECHγδ and DPTE are of high human health concern as they may contribute to changes in prostate growth, histology and function.
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| 34. |
- Beronius, Anna, et al.
(författare)
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Risk to all or none? A comparative analysis of controversies in the health risk assessment of Bisphenol A
- 2010
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 29:2, s. 132-146
-
Tidskriftsartikel (refereegranskat)abstract
- Bisphenol A (BPA) is an endocrine disruptor for which health risk assessment has proven controversial. Conclusions regarding health risks of BPA vary between assessments from "there is no risk to any part of the population" to "there is risk to the entire population". We have carried out a literature study investigating what might be the scientific and/or policy-related reasons for these differences. Ten risk assessments for BPA were scrutinized and several factors were compared between assessments, including estimations of exposure levels, identification of critical study and NOAEL, assessment factors and significance attributed to reports of low-dose effects. Differences in conclusions were mainly influenced by the evaluation of low-dose effects and the uncertainties surrounding the significance of these data for health risk assessment. The results illustrate the impact of differences in risk assessment policy and expert judgment on the risk assessment process and highlight the importance of transparency in this process.
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| 35. |
- Björk, Christel, et al.
(författare)
-
Androgen receptor CAG repeat length modifies the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on receptor activity in human prostate cells.
- 2012
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 1873-1708 .- 0890-6238.
-
Tidskriftsartikel (refereegranskat)abstract
- Increased incidence of prostate cancer has been reported in men exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). TCDD acts through the aryl hydrocarbon receptor (AhR), which interacts with the androgen receptor (AR). The AR gene contains a polymorphic CAG repeat that influences its transcriptional activity. We investigated the influence of TCDD on prostate cancer cells (PC-3) and non-tumor prostate cells (PNT1A) on 5α-dihydrotestosterone-activated ARs containing CAG repeats within normal length range (16, 22, and 28). The AhR target gene CYP1A1 mRNA expression was induced by TCDD, but was not affected by the AR CAG length. TCDD had no effect on AR activity in PC-3 cells, whereas the shortest AR variant was induced by TCDD in PNT1A cells. In conclusion, the CAG length dependent effect of TCDD on AR activity in PNT1A, but not in PC-3 cells, indicates as a cell-specific effect of TCDD on AR activity.
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| 36. |
- Björk, Christel, et al.
(författare)
-
Persistent organic pollutants have dose and CAG repeat length dependent effects on androgen receptor activity in vitro
- 2011
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 32, s. 293-297
-
Tidskriftsartikel (refereegranskat)abstract
- Recently, the effect of exposure to persistent organic pollutants (POPS) on sperm concentration was only seen in men with a short androgen receptor (AR) gene CAG repeat. In order to investigate whether these effects could be observed also in vitro, we tested the impact of 2,2’,4,4’,5,5’-hexachlorobiphenyl (CB-153) and 1,1-bis-(4-chlorophenyl)-2,2-dichloroethene (4,4’-DDE) on 5 alpha-dihydrotestosterone activated ARs containing 16,22 and 28 CAG repeats, respectively. Single exposure to 4,4’-DDE had the most pronounced effect on the AR activity containing 16 CAG repeats, whereas 28 CAG was the most sensitive variant when a mixture of the two compounds was added. Thus, our in vitro results have confirmed the in vivo data indicating a CAG repeat length dependent effect of endocrine disrupters on the AR activity.
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| 37. |
- Bondesson, Maria, et al.
(författare)
-
A CASCADE of effects of bisphenol A.
- 2009
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 28:4, s. 563-7
-
Tidskriftsartikel (refereegranskat)
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| 38. |
- Borg, D., et al.
(författare)
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Tissue distribution of S-35-labelled perfluorooctane sulfonate (PFOS) in C57Bl/6 mice following late gestational exposure
- 2010
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 30:4, s. 558-565
-
Tidskriftsartikel (refereegranskat)abstract
- Exposure of rodents in utero to perfluorooctane sulfonate (PFOS) impairs perinatal development and survival Following intravenous or gavage exposure of C57Bl/6 mouse dams on gestational day (GD) 16 to S-35-PFOS (12 5 mg/kg) we determined the distribution in dams fetuses (GD18 and GD20) and pups (postnatal day 1 PND1) employing whole-body autoradiography and liquid scintillation counting In dams levels were highest in liver and lungs After placental transfer S-35-PFOS was present on GD18 at 2-3 times higher levels in lungs liver and kidneys than in maternal blood In PND1 pups levels in lungs were significantly higher than in GD18 fetuses A heterogeneous distribution of S-35-PFOS was observed in brains of fetuses and pups with levels higher than in maternal brain This first demonstration of substantial localization of PFOS to both perinatal and adult lungs is consistent with evidence describing the lung as a target for the toxicity of PFOS at these ages.
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| 39. |
- Bredhult, Carolina, et al.
(författare)
-
Effects of some endocrine disruptors on the proliferation and viability of human endometrial endothelial cells in vitro
- 2007
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 23:4, s. 550-559
-
Tidskriftsartikel (refereegranskat)abstract
- Endocrine disrupting chemicals (EDCs) pose a potential threat to human reproductive health. We studied the proliferation and viability of human endometrial endothelial cells (HEECs) in vitro after exposure to 2,2-bis(o,p-chlorophenyl)-1,1,1-trichloroethane (o,p′-DDT), 3,3′,4,4′-tetrachlorobiphenyl (CB 77), 3,3′,4,4′,5-pentachlorobiphenyl (CB 126), di-n-butyl phthalate (DBP), bisphenol A (BPA), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and 17β-oestradiol, progesterone, 17α-ethynyl oestradiol and levonorgestrel. Cell proliferation was studied using immunocytochemistry for PCNA expression and a 5-bromo-2′-deoxyuridine assay. Cell viability was studied by vital staining with propidium iodide and Hoechst 33258. HEECs in primary culture responded with increased proliferation to oestradiol and with decreased proliferation to levonorgestrel and the EDCs. Some EDCs also affected cell viability and increased the proportion of necrotic cells. However, the decrease in proliferation in response to DBP and TCDD cannot be explained by cell death. In light of these results, it is possible that the EDCs could have effects in vivo as well as in vitro, and influence processes involving for example endometrial angiogenesis.
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| 40. |
- Bredhult, Carolina, et al.
(författare)
-
Gene expression analysis of human endometrial endothelial cells exposed to Bisphenol A
- 2009
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 28:1, s. 18-25
-
Tidskriftsartikel (refereegranskat)abstract
- Bisphenol A (BPA) can affect reproductive tissues in several species. Recently, treatment of human endometrial endothelial cells (HEECs) with 100 microM BPA decreased their proliferation and viability. In the present study, 50 microM BPA decreased HEEC proliferation, and microarray analyses of five HEEC cultures revealed that BPA affected biological processes associated with proliferation. Expression of three of the most differentially expressed genes identified in the gene array analysis, SPBC25, SGOL2 and CDCA8, was verified by real-time qRT-PCR in five HEEC cultures obtained from women in the proliferative phase and in five cultures obtained from women in the secretory phase of the menstrual cycle after treatment with BPA. This study supports our previous findings of decreased cell proliferation and increased cell death in response to BPA, and may offer important clues to the mechanisms of action of BPA. Furthermore, the study implies a possible impact of BPA on female fertility functions.
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| 41. |
- Bredhult, Carolina, et al.
(författare)
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Study of the relation between the incidence of uterine leiomyomas and the concentrations of PCB and DDT in Baltic gray seals
- 2008
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 25:2, s. 247-255
-
Tidskriftsartikel (refereegranskat)abstract
- Exposure to environmental contaminants is believed to be associated with the previously described decrease in the reproduction rate of Baltic gray seals. In the present study the prevalence of uterine leiomyomas was investigated in 257 Baltic gray seal females examined during 1973-2007, in relation to the levels of polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT) in Baltic biota, using an estimated exposure index. Additionally, the proliferative activity in leiomyomas, occurrence of corpora lutea, and blubber concentrations of PCB and DDT were investigated in a subset of females. Leiomyomas were only found in females 22-41 years old, at a prevalence of 65%. No differences in blubber concentrations of PCB or DDT were detected between the subset of leiomyoma-bearing females and reference females, but the estimated exposure index indicated that the PCB level in Baltic biota might be related to the leiomyoma prevalence in Baltic gray seal females.
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| 42. |
- Brokken, Leon, et al.
(författare)
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Interactions between polymorphisms in the aryl hydrocarbon receptor signalling pathway and exposure to persistent organochlorine pollutants affect human semen quality.
- 2014
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 1873-1708 .- 0890-6238. ; 49:Jul 30, s. 65-73
-
Tidskriftsartikel (refereegranskat)abstract
- Persistent organic pollutants (POPs) may affect male reproductive function. Many dioxin-like POPs exert their effects by activation of the aryl hydrocarbon receptor (AHR) signalling pathway. We analysed whether gene-environment interactions between polymorphisms in AHR (R554K) and AHR repressor (AHRR P185A) and serum levels of markers of POP exposure 1,1-bis-(4-chlorophenyl)-2,2-dichloroethene (p,p'-DDE) and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) are associated with 21 parameters of male reproductive function in 581 proven-fertile European and Greenlandic men. In Greenlandic men, AHR variants significantly modified the association between serum levels of both p,p'-DDE and CB-153 and inhibin B levels, sperm chromatin integrity, and seminal zinc levels. In the total cohort, interactions between AHRR variants and serum levels of CB-153 were associated with sperm chromatin integrity and the expression of the pro-apoptotic marker protein Fas. The data indicate that susceptibility to adverse effects of POP exposure on male reproductive function is dependent on polymorphisms in genes involved in AHR signalling.
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| 43. |
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| 44. |
- Carlsson, Gunnar, et al.
(författare)
-
Developmental toxicity of albendazole and its three main metabolites in zebrafish embryos
- 2011
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 32, s. 129-137
-
Tidskriftsartikel (refereegranskat)abstract
- Albendazole (ABZ) is used as an anthelmintic drug in humans and animals. ABZ has been shown to cause developmental toxicity in experimental animals, however it is not clear if this is caused by the parent compound or a metabolite. Zebrafish embryos were exposed from 1 to 144 hpf (hours post fertilization) to investigate the developmental toxicity of ABZ, the first metabolite albendazole sulphoxide and the subsequent metabolites albendazole sulphone (ABZSO(2)) and albendazole-2-aminosulphone (ABZSO(2)NH(2)). The results showed that ABZ caused malformations of head and tail and embryonic lethality from 0.3 mu M. In contrast, the metabolites did not display developmental toxicity at any tested concentration. Dechorionation did not influence the developmental toxic potential of ABZ and ABZSO, indicating that bioavailability was not a limiting factor. Chemical analysis showed that at sublethal concentrations, most of ABZ was metabolized to ABZSO. The results demonstrate that in zebrafish embryos ABZ rather than ABZSO displays developmental toxicity. (C) 2011 Elsevier Inc. All rights reserved.
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| 45. |
- Chelslín, Felix, 1991-, et al.
(författare)
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Smoking during pregnancy is associated with the placental proteome
- 2023
-
Ingår i: Reproductive Toxicology. - : Elsevier. - 0890-6238 .- 1873-1708. ; 119
-
Tidskriftsartikel (refereegranskat)abstract
- Maternal smoking during pregnancy (MSDP) is a significant risk factor for the development of foetal, neonatal, and childhood morbidities. We hypothesized that infants exposed to MSDP have a distinct proteomic expression in their term placentas compared to infants without such an exposure. A total of 39 infants exposed (cord blood cotinine levels of >1ng/ml) and 44 infants not exposed to MSDP were included in the study. Women with chronic disease, body mass index of >30, or a history of uterine surgery were excluded. Total proteome abundance was analysed with quantitative mass spectrometry. For univariate analysis of differences in placental protein levels between groups, ANOVA with multiple testing corrections by the Benjamini-Hochberg method was used. For multivariate analysis, we used principal component analysis, partial least squares, lasso, random forest, and neural networks. The univariate analyses showed four differentially abundant proteins (PXDN, CYP1A1, GPR183, and KRT81) when heavy and moderate smoking groups were compared to non-smokers. With the help of machine learning, we found that an additional six proteins (SEPTIN3, CRAT, NAAA, CD248, CADM3, and ZNF648) were discriminants of MSDP. The placental abundance of these ten proteins together explained 74.1% of the variation in cord blood cotinine levels (p = 0.002). Infants exposed to MSDP showed differential abundance of proteins in term placentas. We report differential placental abundance of several proteins for the first time in the setting of MSDP. We believe that these findings supplement the current understanding of how MSDP affects the placental proteome.
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| 46. |
- Christensen, P S, et al.
(författare)
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Environmental cadmium and lead exposure and anti-Müllerian hormone in pregnant women
- 2016
-
Ingår i: Reproductive Toxicology. - : Elsevier BV. - 1873-1708 .- 0890-6238. ; 61, s. 114-119
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Anti-Müllerian Hormone (AMH) has been suggested as a marker for ovarian function. Cadmium and lead have been suggested to reduce female fecundity. In this study we aimed to investigate whether environmental exposure to cadmium and lead was associated with alterations in serum-AMH.MATERIALS AND METHOD: The associations between serum-AMH and whole blood cadmium or lead were investigated by general linear models in a population-based sample of 117 pregnant women.RESULTS: The mean concentrations of blood cadmium and lead were 0.71μg/L and 17.4μg/L, respectively. The mean serum-AMH was 17.3pmol/L. No association between lead and AMH was detected. In the cadmium analysis the adjusted mean AMH level (95% CI) in the highest exposure tertile was 12.4 (6.4;23.8) compared to 5.6 (2.7;11.4) in the lowest exposure tertile (p=0.06).CONCLUSION: The study provides suggestive evidence that environmental exposure to cadmium, but not lead, may alter the level of AMH.
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| 47. |
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| 48. |
- Danielsson, Bengt R., et al.
(författare)
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Embryonic cardiac arrhythmia and generation of reactive oxygen species : common teratogenic mechanism for IKr blocking drugs
- 2007
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 0890-6238 .- 1873-1708. ; 24:1, s. 42-56
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Tidskriftsartikel (refereegranskat)abstract
- In the adult organism, it is well established that hypoxia followed by reperfusion may be fatal and result in generation of reactive oxygen species (ROS) and subsequent tissue damage. There is also considerable evidence that temporary decrease or interruption in oxygen supply to the embryo and ROS generation during reperfusion result in tissue damage in embryonic tissues. A wide spectrum of different malformations by transient embryonic hypoxia could be produced, depending on the duration, extent, and timing of the hypoxic event. It is the contention of this paper that drugs that block the potassium channel IKr, either as an intended pharmacologic effect or as an unwanted side-effect, are potentially teratogenic by a common ROS related mechanism. Drugs blocking the IKr channel, such as almokalant, dofetilide, phenytoin, cisapride and astemizole, do all produce a similar pattern of hypoxia-related malformations. Mechanistic studies show that the malformations are preceded by embryonic cardiac arrhythmia and periods of hypoxia/reoxygenation in embryonic tissues. Pretreatment or simultaneous treatment with radical scavengers with capacity to capture ROS, markedly decrease the teratogenicity of different IKr blocking drugs. A second aim of this review is to demonstrate that the conventional design of teratology studies is not optimal to detect malformations caused by IKr blocking drugs. Repeated high doses result in high incidences of embryonic death due embryonic cardiac arrhythmia, thus masking their teratogenic potential. Instead, single dosing on specific days is proposed to be a better way to characterize the teratogenic potential of Ikr blocking drugs.
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| 49. |
- Danielsson, Bengt, et al.
(författare)
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Use of ondansetron during pregnancy and congenital malformations in the infant.
- 2014
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 1873-1708 .- 0890-6238. ; 50, s. 134-137
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Tidskriftsartikel (refereegranskat)abstract
- The study investigates teratogenic risks with ondansetron (Zofran(®)). Data from the Swedish Medical Birth Register combined with the Swedish Register of Prescribed Drugs were used to identify 1349 infants born of women who had taken ondansetron in early pregnancy, 1998-2012. Presence of congenital malformations in the offspring was identified with three national health registers. In a Mantel-Haenszel analysis adjustment was made for year of delivery, maternal age, parity, smoking in early pregnancy and pre-pregnancy body mass index. Risks were expressed as odds or risk ratios with 95% confidence intervals. No statistically significantly increased risk for a major malformation was found. The risks for a cardiovascular defect and notably a cardiac septum defect were increased and statistically significant (OR=1.62, 95% CI 1.04-2.14, and RR 2.05, 95% CI 1.19-3.28, respective). The teratogenic risk with ondansetron is low but an increased risk for a cardiac septum defect is likely.
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| 50. |
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