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31.
Opale Coutant Céline Jézéquel Karel Mokany Isabel Cantera Raphaël Covain Alice Valentini Tony Dejean Sébastien Brosse Jérôme Murienne 《Global Change Biology》2023,29(7):1741-1758
Freshwater ecosystems are among the most endangered ecosystem in the world. Understanding how human activities affect these ecosystems requires disentangling and quantifying the contribution of the factors driving community assembly. While it has been largely studied in temperate freshwaters, tropical ecosystems remain challenging to study due to the high species richness and the lack of knowledge on species distribution. Here, the use of eDNA-based fish inventories combined to a community-level modelling approach allowed depicting of assembly rules and quantifying the relative contribution of geographic, environmental and anthropic factors to fish assembly. We then used the model predictions to map spatial biodiversity and assess the representativity of sites surveyed in French Guiana within the EU Water Framework Directive (WFD) and highlighted areas that should host unique freshwater fish assemblages. We demonstrated a mismatch between the taxonomic and functional diversity. Taxonomic assemblages between but also within basins were mainly the results of dispersal limitation resulting from basin isolation and natural river barriers. Contrastingly, functional assemblages were ruled by environmental and anthropic factors. The regional mapping of fish diversity indicated that the sites surveyed within the EU WFD had a better representativity of the regional functional diversity than taxonomic diversity. Importantly, we also showed that the assemblages expected to be the most altered by anthropic factors were the most poorly represented in terms of functional diversity in the surveyed sites. The predictions of unique functional and taxonomic assemblages could, therefore, guide the establishment of new survey sites to increase fish diversity representativity and improve this monitoring program. 相似文献
32.
Environmental influences on local amphibian diversity: the role of floods on river basins 总被引:2,自引:1,他引:1
We tested two hypotheses about boundary units and seven about environmental control of species diversity in order to explain geographical trends in the richness of amphibian species in the Mediterranean watershed of the southern coast of the Iberian Peninsula. The number of amphibian species tends to decrease from west to east. The longitudinal trend in the richness of amphibian species actually occurs on passing from one basin to another, but there is not any longitudinal trend within the basins. Multivariate analyses confirmed that the disturbances of episodic river-basin floodings were the principal factor which controls the richness of amphibian species. They explained 94.8% of the observed variations in the richness of amphibian species in this area, according to the intermediate disturbance hypothesis.We propose hydrographic basins as suitable geographical units for further biogeographical analysis and for considering the role of disturbances produced by floods in the environmental control of species diversity. 相似文献
33.
Wing Y. Cheung Jean-Charles Côté Diane L. Benoit Benoit S. Landry 《Plant Molecular Biology Reporter》1993,11(2):142-155
We have designed a simple and rapid assay for chloroplast-based triazine resistance in higher plants using PCR amplification
of thepsbA gene coupled toMaeI digestion of the amplified product to distinguish triazine resistant from sensitive biotypes. Our assay is universal and
avoids the need of lengthy procedures of previously published assays, which either required spraying of seedlings in a controlled
environment, quantification of chlorophyll fluorescence of leaf discs after incubation in triazine solution, DNA sequencing
of thepsbA gene, or Southern-blot analysis. Our diagnostic system is qualitative, reliable, fast and simple. More than 100 seedlings
taken directly from the field can be analyzed in one day. This system has a direct application towards a more rational use
of herbicides in production fields. It also represents a valuable tool to monitor spreading of resistant biotypes through
time and space and can serve as a model system applicable to other gene monitoring needs. 相似文献
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35.
Flavio Alexandre Carvalho Natália Valadares de Moraes Antônio Eduardo Miller Crotti Eduardo José Crevelin André Gonzaga dos Santos 《化学与生物多样性》2023,20(9):e202300492
Casearia species are found in the America, Africa, Asia, and Australia and present pharmacological activities, besides their traditional uses. Here, we reviewed the chemical composition, content, pharmacological activities, and toxicity of the essential oils (EOs) from Casearia species. The EO physical parameters and leaf botanical characteristics were also described. The bioactivities of the EOs from the leaves and their components include cytotoxicity, anti-inflammatory, antiulcer, antimicrobial, antidiabetic, antioxidant, antifungal, and antiviral activities. The main components associated with these activities are the α-zingiberene, (E)-caryophyllene, germacrene D, bicyclogermacrene, spathulenol, α-humulene, β-acoradiene, and δ-cadinene. Data on the toxicity of these EOs are scarce in the literature. Casearia sylvestris Sw. is the most studied species, presenting more significant pharmacological potential. The chemical variability of EOs components was also investigated for this species. Caseria EOs have relevant pharmacological potential and must be further investigated and exploited. 相似文献
36.
37.
Ricardo O. Louro Teresa Catarino Carlos A. Salgueiro Jean LeGall António V. Xavier 《Journal of biological inorganic chemistry》1996,1(1):34-38
Using potentiometric titrations, two protons were found to participate in the redox-Bohr effect observed for cytochrome c
3 from Desulfovibrio vulgaris (Hildenborough). Within the framework of the thermodynamic model previously presented, this finding supports the occurrence
of a concerted proton-assisted 2e– step, ideally suited for the coupling role of cytochrome c
3 to hydrogenase. Furthermore, at physiological pH, it is shown that when sulfate-reducing bacteria use H2 as energy source, cytochrome c
3 can be used as a charge separation device, achieving energy transduction by energising protons which can be left in the acidic
periplasmic side and transferring deenergised electrons to sulfate respiration. This mechanism for energy transduction, using
a full thermodynamic data set, is compared to that put forward to explain the proton-pumping function of cytochrome c oxidase. 相似文献
38.
39.
A five year study was conducted in a 100–120 year old even-aged sugar maple stand in southern Quebec (46°07N 73° 56W; 305 m altitude) to explore the effect of different fertilization formulations aimed at 1) correcting the most common nutrient deficiencies observed in declining maple stands (K and Mg), 2) decreasing soil acidity, and 3) simulating enrichment with atmospheric N. Seven fertilizer mixtures were applied in the spring of 1987: 400 kg ha-1 of K2SO4, CaCO3, CaMg(CO3)2, (NH4)2SO4, complete fertilizer (Maplegro) and 800 kg ha-1 of an equal mixture of K2SO4+CaCO3 or K2SO4+CaMg(CO3)2. The site was divided into twenty-four 25×25 m plots and treatments including control were replicated three times. Leaves and soils (organic and mineral) were sampled in 1987, 1988 and 1991. Trees were cored at 1.2 m to measure their response in diameter growth. The application of K2SO4+CaMg(CO3)2 was the only treatment that significantly increased (+13%) the average growth rate over the five year period after fertilization. The application of (NH4)2SO4, Maplegro, CaMg(CO3)2 and K2SO4 reduced growth relative to the control for the five year period by 29, 24, 20 and 12 %, respectively. Positive and negative effects on growth can be explained mainly in terms of changes in leaf K. Both the application of Maplegro and (NH4)2SO4 increased soil P availability. Overall, the rate of growth showed a cubic pattern of change over the 5 year period with peaks in 1988 and 1991. Trees in control plots went from a limiting foliar status of Ca and Mg, and surplus N in 1987 to a surplus of Ca and Mg, and lower N concentration in 1991. Our results suggest that nutrient deficiencies observed at our site were associated with a disturbance of the biogeochemical cycle of nutrients rather than soil nutrient depletion.Abbreviations BS
base saturation
- CEC
cation exchange capacity
- DRIS
diagnosis and recommendation integrated system 相似文献
40.
Fresh and dry body weights (FW, DW) were greater for adult southern green stink bug,Nezara viridula (L.) than for the brown stink bug,Euschistus heros F. throughout the year in southern Brazil. FemalesN. viridula significantly increased FW and DW in late summer-early autumn, and during mid-spring; femaleE. heros did not show the same rates of increase in FW and DW. FemaleN. viridula were heavier than males, particularly during summer; however, female and maleE. heros were generally similar in weight.E. heros contained significantly greater amounts of lipid thanN. viridula, during mid-autumn to early-spring (April–September). Survivorship (%) and total longevity ofE. heros adults provided water only was greater (34.6–24.6 days, for females and males) than that forN. viridula (14.8–13.0 days); without water and food, longevity was drastically reduced (<7 days) for both species. 相似文献