25 research outputs found

    Chemoenzymatic Preparation of Sugar-Based Hydrogels

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    We have prepared sugar-based hydrogels using a chemoenzymatic synthetic approach. Specifically, the regioselectivity of enzymes was used to prepare sugar acrylate monomers. These monomers were polymerized with a crosslinker in a standard free radical polymerization. The polymers consist of a polyacrylate backbone with sucrose, (α-methyl glucoside, or β-methyl galactoside pendant groups. These materials are highly water absorbent swelling to more than 100 times their initial weight when placed in water. The degree of swelling for poly(β-methyl galactoside 6-acrylate) hydrogel was relatively insensitive to pH (from pH 4.5-9) and ionic strength (0.15-3 M NaCl). Potential applications of these materials include waterabsorbents and drug delivery systems

    Global genetic diversity, lineage distribution, and Wolbachia infection of the alfalfa weevil Hypera postica (Coleoptera: Curculionidae)

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    The alfalfa weevil (Hypera postica) is a well‐known example of a worldwide‐distributed pest with high genetic variation. Based on the mitochondrial genes, the alfalfa weevil clusters into two main mitochondrial lineages. However, there is no clear picture of the global diversity and distribution of these lineages; neither the drivers of its diversification are known. However, it appears likely that historic demographic events including founder effects played a role. In addition, Wolbachia, a widespread intracellular parasite/symbiont, likely played an important role in the evolution of the species. Wolbachia infection so far was only detected in the Western lineage of H. postica with no information on the infecting strain, its frequency, and its consequences on the genetic diversity of the host. We here used a combination of mitochondrial and nuclear sequences of the host and sequence information on Wolbachia to document the distribution of strains and the degree of infection. The Eastern lineage has a higher genetic diversity and is found in the Mediterranean, the Middle East, Eastern Europe, and eastern America, whereas the less diverse Western lineage is found in Central Europe and the western America. Both lineages are infected with the same common strain of Wolbachia belonging to Supergroup B. Based on neutrality tests, selection tests, and the current distribution and diversification of Wolbachia in H. postica, we suggested the Wolbachia infection did not shape genetic diversity of the host. The introduced populations in the United States are generally genetically less diverse, which is in line with founder effects
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