| 1. |
- Junker, Robert R., et al.
(författare)
-
Covariation and phenotypic integration in chemical communication displays : Biosynthetic constraints and eco-evolutionary implications
- 2018
-
Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 220:3, s. 739-749
-
Tidskriftsartikel (refereegranskat)abstract
- Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta-analysis to characterize patterns of covariation in CCDs and identified functional or biosynthetically constrained modules. Poorly integrated plant CCDs (i.e. low covariation between scent compounds) support the notion that plants often utilize one or few key compounds to repel antagonists or to attract pollinators and enemies of herbivores. Animal CCDs (mostly insect pheromones) were usually more integrated than those of plants (i.e. stronger covariation), suggesting that animals communicate via fixed proportions among compounds. Both plant and animal CCDs were composed of modules, which are groups of strongly covarying compounds. Biosynthetic similarity of compounds revealed biosynthetic constraints in the covariation patterns of plant CCDs. We provide a novel perspective on chemical communication and a basis for future investigations on structural properties of CCDs. This will facilitate identifying modules and biosynthetic constraints that may affect the outcome of selection and thus provide a predictive framework for evolutionary trajectories of CCDs in plants and animals.
|
|
| 2. |
- Manninen, AM, et al.
(författare)
-
The role of low-level ozone exposure and mycorrhizas in chemical quality and insect herbivore performance on Scots pine seedlings
- 2001
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013. ; 6:1, s. 111-121
-
Tidskriftsartikel (refereegranskat)abstract
- The effects of low-level ozone exposure and suppression of natural mycorrhizas on the above-ground chemical quality of Scots pine (Pinus sylvestris L.) needles and insect herbivore performance were studied in a two-year field experiment. Seedlings were fumigated with the ozone doses 1.5–1.7 times the ambient, and natural mycorrhizal infection level was about 35% reduced in roots with fungicide propiconazole. On ozone-exposed seedlings the mean relative growth rate (MRGR) of Lygus rugulipennis Popp. nymphs was lower than on ambient ozone seedlings, but Gilpinia pallida Klug sawfly larvae grew better on elevated ozone seedlings than on ambient ozone seedlings. MRGR of Schizolachnus pineti Fabr. and Cinara pinea L. aphid nymphs or Neodiprion sertifer Geoffr. sawfly larvae or the oviposition of L. rugulipennis and N. sertifer were not affected by ozone exposure. Although ozone exposure did not affect total phenolics, total terpene, total or individual resin acid, total free amino acid, nutrient or sugar concentrations in needles, MRGR of L. rugulipennis positively correlated with total terpenes and MRGR of G. pallida positively with total amino acids. In addition, ozone exposure increased serine and proline concentration and marginally also starch concentration in needles. When mycorrhizas were reduced with fungicide, only MRGR of L. rugulipennis nymphs increased, but performance of other insect herbivores studied was not changed. However, number of L. rugulipennis eggs correlated positively with mycorrhizal infection level and also with total sugars. Reduction of mycorrhizas did not strongly affect the concentrations of analysed compounds in needles, because only phosphorus and potassium and some individual resin acids were reduced by fungicide treatment. These results suggest that low-level ozone exposure and moderately declined mycorrhizal infection do not drastically affect either the above-ground chemical quality of Scots pine seedlings or performance of studied insect herbivores.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Falck, Emma, et al.
(författare)
-
Interaction of fusidic acid with lipid membranes: Implications to the mechanism of antibiotic activity
- 2006
-
Ingår i: Biophysical Journal. - : Elsevier BV. - 1542-0086 .- 0006-3495. ; 91:5, s. 1787-1799
-
Tidskriftsartikel (refereegranskat)abstract
- We have studied the effects of cholesterol and steroid-based antibiotic fusidic acid (FA) on the behavior of lipid bilayers using a variety of experimental techniques together with atomic-scale molecular dynamics simulations. Capillary electrophoretic measurements showed that FA was incorporated into fluid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine membranes. Differential scanning calorimetry in turn showed that FA only slightly altered the thermodynamic properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayers, whereas cholesterol abolished all endotherms when the mole fraction of cholesterol (X-chol) was > 0.20. Fluorescence spectroscopy was then used to further characterize the influence of these two steroids on DPPC large unilamellar vesicles. In the case of FA, our result strongly suggested that FA was organized into lateral microdomains with increased water penetration into the membrane. For cholesterol/DPPC mixtures, fluorescence spectroscopy results were compatible with the formation of the liquid-ordered phase. A comparison of FA and cholesterol-induced effects on DPPC bilayers through atomistic molecular dynamics simulations showed that both FA and cholesterol tend to order neighboring lipid chains. However, the ordering effect of FA was slightly weaker than that of cholesterol, and especially for deprotonated FA the difference was significant. Summarizing, our results show that FA is readily incorporated into the lipid bilayer where it is likely to be enriched into lateral microdomains. These domains could facilitate the association of elongation actor-G into lipid rafts in living bacteria, enhancing markedly the antibiotic efficacy of FA.
|
|
| 8. |
|
|
| 9. |
- Hintikka, E. -L., et al.
(författare)
-
Mycotoxins in the ventilation systems of four schools in Finland
- 2009
-
Ingår i: World Mycotoxin Journal. - 1875-0796. ; 2:4, s. 369-379
-
Tidskriftsartikel (refereegranskat)abstract
- Some fungal species have been listed as a problem causing fungi in indoor air and most of this group are known to produce mycotoxins. So far, mycotoxins have been found in building materials and in samples representing settled indoor air dust, as well in air samples from industrial or agricultural environments. The present paper presents the results of a mycological study and mycotoxin analyses of dust collected from mechanical ventilation systems in four school buildings in southern Finland. The aim of this work was to answer the question 'Are there mycotoxins in ventilation systems and if so, from where do they originate?' A total of 40 mycotoxins representing indoor and outdoor sources alike were screened in this study, while cultivable fungi were screened using four different cultivation media. Mycotoxins were present in all ventilation systems studied, both in the supply and the exhaust systems examined. The mycotoxins found included satratoxins, verrucarol, trichodermol, enniatins, beauvericin, penicillic acid, sterigmatocystin, chaetoglobosin A, and aflatoxins B-1. The mycotoxins were present in minute quantities (pg-ng/g or pg-ng/cm(2)). The fungal genera associated with respective mycotoxins were found in most of the same sources. Since much the same mycotoxins could be established in both exhaust and supply air systems, it would appear that the mycotoxins found in the schools studied do not for the most part originate from sources within the building but are either normal artefacts of incoming supply air or concentrate or are perhaps produced within the ventilation systems due to infrequent changing of filters and maintenance/cleaning of ventilation ducts and associated parts of the systems.
|
|
| 10. |
- Kasurinen, A, et al.
(författare)
-
Below-ground responses of silver birch trees exposed to elevated CO2 and O-3 levels during three growing seasons
- 2005
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 11:7, s. 1167-1179
-
Tidskriftsartikel (refereegranskat)abstract
- Field-growing silver birch (Betula pendula Roth) clones (clone 4 and 80) were exposed to elevated CO2 and O-3 in open-top chambers for three consecutive growing seasons (1999-2001). At the beginning of the OTC experiment, all trees were 7 years old. We studied the single and interaction effects of CO2 and O-3 on silver birch below-ground carbon pools (i.e. effects on fine roots and mycorrhizas, soil microbial communities and sporocarp production) and also assessed whether there are any clonal differences in these below-ground CO2 and O-3 responses. The total mycorrhizal infection level of both clones was stimulated by elevated CO2 alone and elevated O-3 alone, but not when elevated CO2 was used in fumigation in combination with elevated O-3. In both clones, elevated CO2 affected negatively light brown/orange mycorrhizas, while its effect on other mycorrhizal morphotypes was negligible. Elevated O-3, instead, clearly decreased the proportions of black and liver-brown mycorrhizas and increased that of light brown/orange mycorrhizas. Elevated O-3 had a tendency to decrease standing fine root mass and sporocarp production as well, both of these O-3 effects mainly manifesting in clone 4 trees. CO2 and O-3 treatment effects on soil microbial community composition (PLFA, 2- and 3-OH-FA profiles) were negligible, but quantitative PLFA data showed that in 2001 the PLFA fungi : bacteria-ratio of clone 80 trees was marginally increased because of elevated CO2 treatments. This study shows that O-3 effects were most clearly visible at the mycorrhizal root level and that some clonal differences in CO2 and O-3 responses were observable in the below-ground carbon pools. In conclusion, the present data suggests that CO2 effects were minor, whereas increasing tropospheric O-3 levels can be an important stress factor in northern birch forests, as they might alter mycorrhizal morphotype assemblages, mycorrhizal infection rates and sporocarp production.
|
|
| 11. |
|
|
| 12. |
- Siddiqui, T. A., et al.
(författare)
-
Bluetooth antenna for metal-cased smart jewellery
- 2020
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 1350-911X .- 0013-5194. ; 56:3, s. 115-117
-
Tidskriftsartikel (refereegranskat)abstract
- This Letter presents a Bluetooth antenna for metal-cased smart jewellery. The designed antenna is competent enough to operate in free space; moreover, antenna performance is investigated with cubical shape model which has the electrical properties similar to human body tissue. The measured prototype achieves 68% total efficiency in the free space and 27% total efficiency when measured with a cubical model in the Bluetooth frequency range of 2.4-2.48 GHz.
|
|
| 13. |
|
|
