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排序方式: 共有75条查询结果,搜索用时 15 毫秒
1.
Matthew J Christmas Julia C Jones Anna Olsson Ola Wallerman Ignas Bunikis Marcin Kierczak Valentina Peona Kaitlyn M Whitley Tuuli Larva Alexander Suh Nicole E Miller-Struttmann Jennifer C Geib Matthew T Webster 《Molecular biology and evolution》2021,38(8):3126
Evidence is accumulating that gene flow commonly occurs between recently diverged species, despite the existence of barriers to gene flow in their genomes. However, we still know little about what regions of the genome become barriers to gene flow and how such barriers form. Here, we compare genetic differentiation across the genomes of bumblebee species living in sympatry and allopatry to reveal the potential impact of gene flow during species divergence and uncover genetic barrier loci. We first compared the genomes of the alpine bumblebee Bombus sylvicola and a previously unidentified sister species living in sympatry in the Rocky Mountains, revealing prominent islands of elevated genetic divergence in the genome that colocalize with centromeres and regions of low recombination. This same pattern is observed between the genomes of another pair of closely related species living in allopatry (B. bifarius and B. vancouverensis). Strikingly however, the genomic islands exhibit significantly elevated absolute divergence (dXY) in the sympatric, but not the allopatric, comparison indicating that they contain loci that have acted as barriers to historical gene flow in sympatry. Our results suggest that intrinsic barriers to gene flow between species may often accumulate in regions of low recombination and near centromeres through processes such as genetic hitchhiking, and that divergence in these regions is accentuated in the presence of gene flow. 相似文献
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Müllberg J Geib T Jostock T Hoischen SH Vollmer P Voltz N Heinz D Galle PR Klouche M Rose-John S 《Journal of immunology (Baltimore, Md. : 1950)》2000,164(9):4672-4677
The genome of human herpes virus 8, which is associated with Kaposi's sarcoma, encodes proteins with similarities to cytokines and chemokines including a homologue of IL-6. Although the function of these viral proteins is unclear, they might have the potential to modulate the immune system. For viral IL-6 (vIL-6), it has been demonstrated that it stimulates IL-6-dependent cells, indicating that the IL-6R system is used. IL-6 binds to IL-6R, and the IL-6/IL-6R complex associates with gp130 which dimerizes and initiates intracellular signaling. Cells that only express gp130 but no IL-6R cannot be stimulated by IL-6 unless a soluble form of the IL-6R is present. This type of signaling has been shown for hematopoietic progenitor cells, endothelial cells, and smooth muscle cells. In this paper we show that purified recombinant vIL-6 binds to gp130 and stimulates primary human smooth muscle cells. IL-6R fails to bind vIL-6 and is not involved in its signaling. A Fc fusion protein of gp130 turned out to be a potent inhibitor of vIL-6. Our data demonstrate that vIL-6 is the first cytokine which directly binds and activates gp130. This property points to a possible role of this viral cytokine in the pathophysiology of human herpes virus 8. 相似文献
4.
Julia C Jones Carmelo Fruciano Falk Hildebrand Hasan Al Toufalilia Nicholas J Balfour Peer Bork Philipp Engel Francis LW Ratnieks William OH Hughes 《Ecology and evolution》2018,8(1):441-451
There is growing recognition that the gut microbial community regulates a wide variety of important functions in its animal hosts, including host health. However, the complex interactions between gut microbes and environment are still unclear. Honey bees are ecologically and economically important pollinators that host a core gut microbial community that is thought to be constant across populations. Here, we examined whether the composition of the gut microbial community of honey bees is affected by the environmental landscape the bees are exposed to. We placed honey bee colonies reared under identical conditions in two main landscape types for 6 weeks: either oilseed rape farmland or agricultural farmland distant to fields of flowering oilseed rape. The gut bacterial communities of adult bees from the colonies were then characterized and compared based on amplicon sequencing of the 16S rRNA gene. While previous studies have delineated a characteristic core set of bacteria inhabiting the honey bee gut, our results suggest that the broad environment that bees are exposed to has some influence on the relative abundance of some members of that microbial community. This includes known dominant taxa thought to have functions in nutrition and health. Our results provide evidence for an influence of landscape exposure on honey bee microbial community and highlight the potential effect of exposure to different environmental parameters, such as forage type and neonicotinoid pesticides, on key honey bee gut bacteria. This work emphasizes the complexity of the relationship between the host, its gut bacteria, and the environment and identifies target microbial taxa for functional analyses. 相似文献
5.
Whole‐cell biotransformation of oleanolic acid by free and immobilized cells of Nocardia iowensis: Characterization of new metabolites 下载免费PDF全文
Benjamin Ludwig Doris Geib Christiane Haas Juliane Steingroewer Thomas Bley Kai Muffler Roland Ulber 《Engineering in Life Science》2015,15(1):108-115
In this study, Nocardia iowensis was used to transform oleanolic acid (OA) into oleanane derivatives. The first derivative, which was found after 24 h of cultivation, was the known and already described OA methyl ester. After 1 week, two other derivatives (oleanonic acid methyl ester and an unknown metabolite) were identified as new products of a biotransformation by N. iowensis. These oleanane metabolites were characterized by HPLC, HPLC‐ESI‐MS, and HPLC‐1H NMR spectroscopy. The biotransformation was performed by suspended and immobilized cells (ICs) of N. iowensis. Cells immobilized in alginate beads were used in order to prepare a continuous process. The substrate uptake of free and ICs was similar, whereas the peak area of OA methyl ester of the ICs was only about 10% of the native cells. However, the final product (oleanonic acid methyl ester) concentrations were similar in both approaches, whereas the unknown metabolite 3 was only detected transiently in the medium of ICs. Based on these results, a new biosynthetic pathway for the biotechnological production of oleanonic acid methyl ester is proposed. 相似文献
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Julian R. Dupuis Sheina B. Sim Michael San Jose Luc Leblanc M. Aftab Hoassain Daniel Rubinoff Scott M. Geib 《Biological invasions》2018,20(5):1211-1228
Population genetics is a powerful tool for invasion biology and pest management, and useful for a range of questions from tracing invasion pathways to informing management decisions with inference of population demographics. Genomics greatly increases the resolution of population-scale analyses, yet outside of model species with extensive genomic resources, few studies have used population genomics in invasion biology. We use genome-wide single nucleotide polymorphisms (SNPs) to investigate population genomic structure with samples from across the range of melon fly, Bactrocera cucurbitae (Coquillett, 1849), a highly polyphagous pest of commercial produce. We then make use of a chromosome-scale genome assembly and gene set to compare signatures of selection across the melon fly’s genome, both across our sampling as a whole and in the context of two independent, established introductions. Using multiple approaches, we find support for six genetic clusters across melon fly’s distribution. Some of these agree with previously identified genetic clusters using microsatellites, but consensus of clusters in mainland and oceanic southeast Asia is confounded by variable sampling between studies. We find few adaptive signatures across the genome, and virtually no unique signatures when comparing the two independent introductions, which suggests that similar management strategies are appropriate across melon fly’s range. This is the first use of genome-wide data to characterize population structure in tephritid fruit fly pests, and our SNP dataset provides a foundation for objective and cost-effective genotyping of previously collected melon fly specimens. Future research needs to focus on truly comprehensive sampling across melon fly’s range to overcome the historic variability of range-wide estimates of population structure for this pest. 相似文献
8.
S H Hoischen P Vollmer P M?rz S Ozbek K S G?tze C Peschel T Jostock T Geib J Müllberg S Mechtersheimer M Fischer J Gr?tzinger P R Galle S Rose-John 《European journal of biochemistry》2000,267(12):3604-3612
Human herpes virus-8 (HHV8) encodes a cytokine named viral interleukin-6 (vIL-6) that shares 25% amino-acid identity with its human homologue. Human IL-6 is known to be a growth and differentiation factor of lymphatic cells and plays a potential role in the pathophysiology of various lymphoproliferative diseases. vIL-6 is expressed in HHV8-associated-diseases including Kaposi's sarcoma, Body-cavity-based-lymphoma and Castleman's disease, suggesting a pathogenetic involvement in the malignant growth of B-cell associated diseases and other malignant tumours. We expressed vIL-6 in Escherichia coli as a fusion protein with recombinant periplasmic maltose binding protein. After cleavage from the maltose binding protein moiety and purification, vIL-6 was shown to be correctly folded using circular dichroism spectroscopy. A rabbit antiserum was raised against the recombinant vIL-6 protein. vIL-6 turned out to be active on cells that expressed gp130 but no IL-6 receptor (IL-6-R) suggesting that, in contrast to human IL-6, vIL-6 stimulated gp130 directly. Accordingly, vIL-6 activity could be inhibited by a soluble gp130 Fc Fusion protein. vIL-6 was shown to induce neuronal differentiation of rat pheochromocytoma cells and to stimulate colony formation of human hematopoietic progenitor cells. Thus, vIL-6 exhibits biologic activity that has only been observed for the IL-6/soluble IL-6-R complex but not for IL-6 alone. These properties are important for the evaluation of the pathophysiological potential of vIL-6. 相似文献
9.
Scott M. Geib Maria del Mar Jimenez-Gasco John E. Carlson Ming Tien Randa Jabbour Kelli Hoover 《Microbial ecology》2009,58(1):199-211
Many insects harbor specific bacteria in their digestive tract, and these gut microbiota often play important roles in digestion
and nutrient provisioning. While it is common for a given insect species to harbor a representative gut microbial community
as a population, how this community is acquired and maintained from generation to generation is not known for most xylophagous
insects, except termites. In this study, we examined acquisition of gut microbiota by the wood-feeding beetle, Anoplophora glabripennis, by identifying and comparing microbial community members among different life stages of the insect and with microbes it
encounters in the environment. Automated ribosomal intergenic spacer analysis was employed to compare bacterial communities
present in the egg and larval stages of A. glabripennis as well as with microbes found in the oviposition site and the surrounding woody tissue. Multivariate analyses were used
to identify relationships between sample type and specific bacterial types (operational taxonomic units). From this analysis,
bacteria that were derived from the environment, the oviposition site, and/or the egg were identified and compared with taxa
found in larvae. Results showed that while some larval microbes were derived from environmental sources, other members of
the larval microbial community appear to be vertically transmitted. These findings could lead to a better understanding of
which microbial species are critical for the survival of this insect and to development of techniques that could be used to
alter this community to disrupt the digestive physiology of the host insect as a biological control measure. 相似文献