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Sökning: hsv:(NATURVETENSKAP) hsv:(Biologi) hsv:(Zoologi) > RISE

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1.
  • Jägerbrand, Annika, 1972-, et al. (författare)
  • Dose–effects in behavioural responses of moths to light in a controlled lab experiment
  • 2023
  • Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Insects play a critical role in providing numerous ecosystem services. However, insect diversity and biomass have been declining dramatically, with artificial light being suggested as a contributing factor. Despite the importance of understanding the dose–effect responses of insects to light emissions, these responses have been rarely studied. We examined the dose–effect responses of the greater wax moth (Galleria mellonella L.) to different light intensities (14 treatments and a dark control) by observing their behavioural responses in a light-tight box equipped with a LED light source (4070 K) and infrared cameras. Our findings reveal dose–effect responses to light, as the frequency of walking on the light source increased with higher light intensity. Additionally, moths exhibited jumps in front of the light source and jump frequency increased with light intensity. No direct flight-to-light behaviour or activity suppression in response to light was observed. Based on our analysis of the dose–effect responses, we identified a threshold value of 60 cd/m2 for attraction (walking on the light source) and the frequency of jumps. The experimental design in this study offers a valuable tool for investigating dose–effect relationships and behavioural responses of various species to different light levels or specific light sources. © 2023, The Author(s).
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2.
  • Kjellberg Jensen, Johan, et al. (författare)
  • Quantifying the influence of urban biotic and abiotic environmental factors on great tit nestling physiology
  • 2023
  • Ingår i: Science of the Total Environment. - : Elsevier B.V.. - 0048-9697 .- 1879-1026. ; 859
  • Tidskriftsartikel (refereegranskat)abstract
    • There is a long history of avian studies investigating the impacts of urbanization. While differences in several life-history traits have been documented, either between urban and rural populations or across generalized urbanization gradients, a detailed understanding of which specific environmental variables cause these phenotypic differences is still lacking. Here, we quantified several local environmental variables coupled to urbanization (air pollution, tree composition, ambient temperature, and artificial light at night [ALAN]) within territories of breeding great tits (Parus major). We linked the environmental variables to physiological measures of the nestlings (circulating fatty acid composition [FA], antioxidant capacity and an oxidative damage marker [malondialdehyde; MDA]), to garner a mechanistic understanding of the impact of urbanization. We found that the antioxidant capacity of nestlings decreased with higher numbers of oak trees and levels of PM2.5 (airborne particulate matter with a diameter < 2.5 μm). Furthermore, the ratio of ω6:ω3 polyunsaturated FAs, important for immune function, was positively correlated with PM2.5 concentration, while being negatively associated with ambient temperature and number of non-native trees in the territory. Body mass and wing length both increased with the number of local oak trees. We also show, through a principal component analysis, that while the environmental variables fall into an urbanization gradient, this gradient is insufficient to explain the observed physiological responses. Therefore, accounting for individual environmental variables in parallel, and thus allowing for interactions between these, is crucial to fully understand of the urban ecosystem. © 2022 The Authors
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3.
  • Lindgren, Johan, et al. (författare)
  • Fossil insect eyes shed light on trilobite optics and the arthropod pigment screen
  • 2019
  • Ingår i: Nature. - : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 573:7772, s. 122-125
  • Tidskriftsartikel (refereegranskat)abstract
    • Fossilized eyes permit inferences of the visual capacity of extinct arthropods1–3. However, structural and/or chemical modifications as a result of taphonomic and diagenetic processes can alter the original features, thereby necessitating comparisons with modern species. Here we report the detailed molecular composition and microanatomy of the eyes of 54-million-year-old crane-flies, which together provide a proxy for the interpretation of optical systems in some other ancient arthropods. These well-preserved visual organs comprise calcified corneal lenses that are separated by intervening spaces containing eumelanin pigment. We also show that eumelanin is present in the facet walls of living crane-flies, in which it forms the outermost ommatidial pigment shield in compound eyes incorporating a chitinous cornea. To our knowledge, this is the first record of melanic screening pigments in arthropods, and reveals a fossilization mode in insect eyes that involves a decay-resistant biochrome coupled with early diagenetic mineralization of the ommatidial lenses. The demonstrable secondary calcification of lens cuticle that was initially chitinous has implications for the proposed calcitic corneas of trilobites, which we posit are artefacts of preservation rather than a product of in vivo biomineralization4–7. Although trilobite eyes might have been partly mineralized for mechanical strength, a (more likely) organic composition would have enhanced function via gradient-index optics and increased control of lens shape.
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4.
  • Lindgren, Johan, et al. (författare)
  • Molecular preservation of the pigment melanin in fossil melanosomes.
  • 2012
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 3:Online 08 May 2012
  • Tidskriftsartikel (refereegranskat)abstract
    • Fossil feathers, hairs and eyes are regularly preserved as carbonized traces comprised of masses of micrometre-sized bodies that are spherical, oblate or elongate in shape. For a long time, these minute structures were regarded as the remains of biofilms of keratinophilic bacteria, but recently they have been reinterpreted as melanosomes; that is, colour-bearing organelles. Resolving this fundamental difference in interpretation is crucial: if endogenous then the fossil microbodies would represent a significant advancement in the fields of palaeontology and evolutionary biology given, for example, the possibility to reconstruct integumentary colours and plumage colour patterns. It has previously been shown that certain trace elements occur in fossils as organometallic compounds, and hence may be used as biomarkers for melanin pigments. Here we expand this knowledge by demonstrating the presence of molecularly preserved melanin in intimate association with melanosome-like microbodies isolated from an argentinoid fish eye from the early Eocene of Denmark.
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5.
  • Moodie, Lindon W. K., et al. (författare)
  • Probing the Structure-Activity Relationship of the Natural Antifouling Agent Polygodial against both Micro- and Macrofoulers by Semisynthetic Modification
  • 2017
  • Ingår i: Journal of natural products (Print). - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 80:2, s. 515-525
  • Tidskriftsartikel (refereegranskat)abstract
    • The current study represents the first comprehensive investigation into the general antifouling activities of the natural drimane sesquiterpene polygodial. Previous studies have highlighted a high antifouling effect toward macrofoulers, such as ascidians, tubeworms, and mussels, but no reports about the general antifouling effect of polygodial have been communicated before. To probe the structural and chemical basis for antifouling activity, a library of 11 polygodial analogues was prepared by semisynthesis. The library was designed to yield derivatives with ranging polarities and the ability to engage in both covalent and noncovalent interactions, while still remaining within the drimane sesquiterpene scaffold. The prepared compounds were screened against 14 relevant marine micro- and macrofouling species. Several of the polygodial analogues displayed inhibitory activities at sub-microgram/mL concentrations. These antifouling effects were most pronounced against the macrofouling ascidian Ciona savignyi and the barnacle Balanus improvisus, with inhibitory activities observed for selected compounds comparable or superior to several commercial antifouling products. The inhibitory activity against the microfouling bacteria and microalgae was reversible and significantly less pronounced than for the macrofoulers. This study illustrates that the macro- and microfoulers are targeted by the compounds via different mechanisms.
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