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921.
Punita Juneja Jewelna Osei-Poku Yung S. Ho Cristina V. Ariani William J. Palmer Arnab Pain Francis M. Jiggins 《PLoS neglected tropical diseases》2014,8(1)
The mosquito Aedes aegypti transmits some of the most important human arboviruses, including dengue, yellow fever and chikungunya viruses. It has a large genome containing many repetitive sequences, which has resulted in the genome being poorly assembled — there are 4,758 scaffolds, few of which have been assigned to a chromosome. To allow the mapping of genes affecting disease transmission, we have improved the genome assembly by scoring a large number of SNPs in recombinant progeny from a cross between two strains of Ae. aegypti, and used these to generate a genetic map. This revealed a high rate of misassemblies in the current genome, where, for example, sequences from different chromosomes were found on the same scaffold. Once these were corrected, we were able to assign 60% of the genome sequence to chromosomes and approximately order the scaffolds along the chromosome. We found that there are very large regions of suppressed recombination around the centromeres, which can extend to as much as 47% of the chromosome. To illustrate the utility of this new genome assembly, we mapped a gene that makes Ae. aegypti resistant to the human parasite Brugia malayi, and generated a list of candidate genes that could be affecting the trait. 相似文献
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Jae Il Lee Seung Kyoon Woo Keun Il Kim Kyung Chan Park Sung Hee Baek Yung Joon Yoo Chin Ha Chung 《Biological procedures online》1998,1(1):92-99
A general method for the assay of deubiquitinating enzymes was described in detail using 125I-labeled ubiquitin-fused αNH-MHISPPEPESEEEEEHYC (referred to as Ub-PESTc) as a substrate. Since the tyrosine residue in the
PESTc portion of the fusion protein was almost exclusively radioiodinated under a mild labeling condition, such as using IODO-BEADS,
the enzymes could be assayed directly by simple measurement of the radioactivity released into acid soluble products. Using
this assay protocol, we could purify six deubiquitinating enzymes from chick skeletal muscle and yeast and compare their specific
activities. Since the extracts of E. coli showed little or no activity against the substrate, the assay protocol should be useful for identification and purification
of eukaryotic deubiquitinating enzymes cloned and expressed in the cells. 相似文献
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Caulobacter crescentus is known to tolerate high levels of uranium [U(VI)], but its detoxification mechanism is poorly understood. Here we show that C. crescentus is able to facilitate U(VI) biomineralization through the formation of U-Pi precipitates via its native alkaline phosphatase activity. The U-Pi precipitates, deposited on the cell surface in the form of meta-autunite structures, have a lower U/Pi ratio than do chemically produced precipitates. The enzyme that is responsible for the phosphatase activity and thus the biomineralization process is identified as PhoY, a periplasmic alkaline phosphatase with broad substrate specificity. Furthermore, PhoY is shown to confer a survival advantage on C. crescentus toward U(VI) under both growth and nongrowth conditions. Results obtained in this study thus highlight U(VI) biomineralization as a resistance mechanism in microbes, which not only improves our understanding of bacterium-mineral interactions but also aids in defining potential ecological niches for metal-resistant bacteria. 相似文献
929.
Biosynthesis of bacterial glycogen: purification and structural and immunological properties of Rhodopseudomonas sphaeroides ADPglucose synthetase. 下载免费PDF全文
ADPglucose synthetase from the photosynthetic bacterium Rhodopseudomonas sphaeroides was purified to greater than 95% purity. The molecular weight of the R. sphaeroides enzyme, as determined by sucrose density gradient ultracentrifugation, was approximately 204,000. The subunit molecular weight of the enzyme based on sodium dodecyl sulfate-gel electrophoresis was 46,000. Although the amino acid composition of the enzyme was similar to that found for the enzymes from Escherichia coli, Salmonella typhimurium, and Rhodospirillum tenue, no apparent homology has been observed between the N-terminal or C-terminal amino acid sequences. Antisera prepared against the ADPglucose synthetase could inhibit the activities of the enzyme from other photosynthetic bacteria. Therefore, some sequence homology may exist within the internal portion of their peptide chain. 相似文献
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Morphological changes of the optic lobe from late embryonic to adult stages in oval squids Sepioteuthis lessoniana 下载免费PDF全文
Yung‐Chieh Liu Wen‐Sung Chung Chun‐Chieh Yu Su‐Ting Hsu Fung‐Lan Chan Tsung‐Han Liu Chia‐Hao Su Yeukuang Hwu N. Justin Marshall Chuan‐Chin Chiao 《Journal of morphology》2018,279(1):75-85
The optic lobe is the largest brain area within the central nervous system of cephalopods and it plays important roles in the processing of visual information, the regulation of body patterning, and locomotive behavior. The oval squid Sepioteuthis lessoniana has relatively large optic lobes that are responsible for visual communication via dynamic body patterning. It has been observed that the visual behaviors of oval squids change as the animals mature, yet little is known about how the structure of the optic lobes changes during development. The aim of the present study was to characterize the ontogenetic changes in neural organization of the optic lobes of S. lessoniana from late embryonic stage to adulthood. Magnetic resonance imaging and micro‐CT scans were acquired to reconstruct the 3D‐structure of the optic lobes and examine the external morphology at different developmental stages. In addition, optic lobe slices with nuclear staining were used to reveal changes in the internal morphology throughout development. As oval squids mature, the proportion of the brain making up the optic lobes increases continuously, and the optic lobes appear to have a prominent dent on the ventrolateral side. Inside the optic lobe, the cortex and the medulla expand steadily from the late embryonic stage to adulthood, but the cell islands in the tangential zone of the optic lobe decrease continuously in parallel. Interestingly, the size of the nuclei of cells within the medulla of the optic lobe increases throughout development. These findings suggest that the optic lobe undergoes continuous external morphological change and internal neural reorganization throughout the oval squid's development. These morphological changes in the optic lobe are likely to be responsible for changes in the visuomotor behavior of oval squids from hatching to adulthood. 相似文献