A major focus in evolutionary biology is to understand how the evolution of organisms relates to changes in their physical environment. In the terrestrial realm, the interrelationships among climate, vegetation, and herbivores lie at the heart of this question. Here we introduce and test a scoring scheme for functional traits present on the worn surfaces of large mammalian herbivore teeth to capture their relationship to environmental conditions. We modeled local precipitation, temperature, primary productivity, and vegetation index as functions of dental traits of large mammal species in 13 national parks in Kenya over the past 60 y. We found that these dental traits can accurately estimate local climate and environment, even at small spatial scales within areas of relatively uniform climate (within two ecoregions), and that they predict limiting conditions better than average conditions. These findings demonstrate that the evolution of key functional properties of organisms may be more reflective of demands during recurring adverse episodes than under average conditions or during isolated severe events.herbivorous mammals | dental traits | ecometrics | Kenya | paleoecology
In this work, magnetite (Fe(3)O(4)) nanoparticles with an average size 10 nm modified by sodium oleate were prepared by the modified controlled chemical coprecipitation method, which can be well dispersed in water and linked well with protein molecules because of the presence of -COOH on their surface. Then magnetic poly(lactic acid) (PLA) and poly(lactic-co-glycolic acid) (PLGA) microspheres containing interferon alpha-2b (IFN-a-2b) were prepared by the modified water-in-oil-in-water solvent evaporation procedure. X-ray powder diffraction analysis, particle size analysis, transmission electron microscopy, scanning electron microscopy, and vibrating-sample magnetometer (VSM) analysis were carried out to examine phase composition, surface and interior morphology, size and size distribution, and magnetic properties of the magnetic microspheres. Also the effects of some important parameters on the magnetic biodegradable microspheres were investigated, such as magnetite dosage in the preparation system, stirring rate of the suspension medium, and concentration of the external aqueous phase. And the antiviral activity of IFN-a-2b encapsulated in the magnetic polymeric microspheres was evaluated by the vesicular stomatitis virus (VSV) cytopathicity inhibition assay. The results showed that the properties of IFN-loaded magnetic PLGA and PLA microspheres were better than the conventional protein-loaded polymeric microspheres, such as perfect magnetic properties, higher protein encapsulation efficiency, and less effect on the antiviral activity of protein. These indicated that the magnetic PLA and PLGA microspheres containing IFN-a-2b exhibited strong potential as targeted-drug delivery vehicles, which could be rapidly localized to the immunization-related tissues easily by an external magnetic field.
The inhibitors present in dilute acid-treated lignocellulosic hydrolysates would show great effect on the growth and product formation of microorganisms. To understand their inhibitory law and mechanism on oleaginous microorganism could help improving the efficiency of lignocellulose hydrolysis, detoxification, and lipid fermentation. The effects of four representative alcohol compounds present in lignocellulosic hydrolysates, including furfuryl alcohol, vanillyl alcohol, catechol, hydroquinone on the cell growth and lipid accumulation of Trichosporon fermentans were systematically investigated in this work. The toxicity of selected alcohol compounds was well related to their log P value except furfuryl alcohol, whose log P value was the minimum but with the highest toxicity to T. fermentans. The inhibition of all the alcohol compounds on the growth of T. fermentans was more serious than on the lipid synthesis. Also, the growth of T. fermentans was more sensitive to the variation of inoculum size, temperature, and initial pH than lipid synthesis in the presence of alcohol compounds. Initial pH had more profound influence on the lipid fermentation than inoculum size and cultural temperature did. Careful control of fermentation conditions could be helpful for improving lipid yield of T. fermentans in lignocellulosic hydrolysates. Among the four alcohol compounds tested, most alcohol compounds showed inhibition on both sugar consumption and malic enzyme activity of T. fermentans. However, vanillyl alcohol had little influence on the malic enzyme activity. Similarly, all alcohol compounds except vanillyl alcohol exerted damage on the cell membrane of T. fermentans.
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