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1.
Ting Zhang Bai‐Ge Miao Bo Wang Yan‐Qiong Peng Clive T. Darwell 《Ecological Entomology》2019,44(6):844-848
1. Species interactions in tightly bound ecological mutualisms often feature highly specialised species' roles in which competitive exclusion may preclude multi‐species coexistence. Among the 800 fig (Ficus) species, it was originally considered that each was pollinated by their own wasp (Agaonidae). However, recent investigations show that this ‘one‐to‐one’ rule often breaks down, as fig species regularly host multiple agaonids but in ways suggesting that competitive processes still mediate biodiversity outcomes. 2. A phenological survey was conducted of the fig–fig wasp pair, Ficus microcarpa and its associated pollinating wasp, alongside its sister species, the cheating wasp, in Xishuangbanna, China. 3. Reproductive output underwent extreme seasonal variation. Seed and pollinator production fell markedly during cooler, drier months, although high levels of fig production continued. However, this resource was predominantly utilised by the cheater species, which offers no pollination services. Pollinators and cheaters rarely co‐occur, suggesting that temporal coexistence is constrained by competition for access to figs. 4. The overall findings indicate periodic rearrangements of mutualism dynamics, probably resulting from a strongly seasonal environment. Sympatric co‐occurrence may result from a window of opportunity for a functionally divergent agaonid, potentially due to constraints on the main pollinator in adapting to variable year‐round conditions that prevent competitive exclusion. 相似文献
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Antigen presenting cells (APCs) in skin can promote either antigen-specific effector functions or antigen tolerance, and thus determine clearance or persistence of cutaneous viral infections. Human papillomavirus (HPV) infections can persist in squamous epithelium in immunocompetent individuals, and some persisting HPV infections, particularly with HPV16, promote malignant epithelial transformation. Here, we investigate whether local expression of the HPV16 protein most associated with malignant transformation, HPV16-E7, affects the phenotype and function of APC subsets in the skin. We demonstrate an expanded population of Langerhans cells in HPV16-E7 transgenic skin with distinct cell surface markers which express immune-modulatory enzymes and cytokines not expressed by cells from non transgenic skin. Furthermore, HPV16-E7 transgene expression in keratinocytes attracts new APC subsets to the epidermis. In vivo migration and transport of antigen to the draining lymph node by these APCs is markedly enhanced in HPV16-E7 expressing skin, whereas antigen-processing, as measured by proteolytic cleavage of DQ-OVA and activation of T cells in vivo by APCs, is significantly impaired. These data suggest that local expression of HPV16-E7 in keratinocytes can contribute to persisting infection with this oncogenic virus, by altering the phenotype and function of local APCs. 相似文献
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Haiyan Miao Jingjing Lu Yibing Guo Hongquan Qiu Yu Zhang Xihao Yao Xiaohong Li Yuhua Lu 《Journal of cellular and molecular medicine》2021,25(7):3654-3664
Pancreatic ductal adenocarcinoma (PDAC) is an invasive and aggressive cancer that remains a major threat to human health across the globe. Despite advances in cancer treatments and diagnosis, the prognosis of PDAC patients remains poor. New and more effective PDAC therapies are therefore urgently required. In this study, we identified a novel host factor, namely the LncRNA TP73-AS1, as overexpressed in PDAC tissues compared to adjacent healthy tissue samples. The overexpression of TP-73-AS1 was found to correlate with both PDAC stage and lymph node metastasis. To reveal its role in PDCA, we targeted TP73-AS1 using LnRNA inhibitors in a range of pancreatic cancer (PC) cell lines. We found that the inhibition of TP73-AS1 led to a loss of MMP14 expression in PC cells and significantly inhibited their migratory and invasive capacity. No effects of TP73-AS1 on cell survival or proliferation were observed. Mechanistically, we found that TP73-AS1 suppressed the expression of the known oncogenic miR-200a. Taken together, these data highlight the prognostic potential of TP73-AS1 for PC patients and highlight it as a potential anti-PDAC therapeutic target. 相似文献
6.
Jin-Ying Cui Han Miao Li-Hong Ding Todd C. Wehner Pan-Na Liu Ye Wang Sheng-Ping Zhang Xing-Fang Gu 《PloS one》2016,11(2)
Spines or trichomes on the fruit of cucumbers enhance their commercial value in China. In addition, glabrous mutants exhibit resistance to aphids and therefore their use by growers can reduce pesticide residues. Previous studies have reported two glabrous mutant plants containing the genes, csgl1 and csgl2. In the present study, a new glabrous mutant, NCG157, was identified showing a gene interaction effect with csgl1 and csgl2. This mutant showed the glabrous character on stems, leaves, tendrils, receptacles and ovaries, and there were no spines or tumors on the fruit surface. Inheritance analysis showed that a single recessive gene, named csgl3, determined the glabrous trait. An F2 population derived from the cross of two inbred lines 9930 (a fresh market type from Northern China that exhibits trichomes) and NCG157 (an American processing type with glabrous surfaces) was used for genetic mapping of the csgl3 gene. By combining bulked segregant analysis (BAS) with molecular markers, 18 markers, including two simple sequence repeats (SSR), nine insertion deletions (InDel) and seven derived cleaved amplified polymorphism sequences (dCAPs), were identified to link to the csgl3 gene. All of the linked markers were used as anchor loci to locate the csgl3 gene on cucumber chromosome 6. The csgl3 gene was mapped between the dCAPs markers dCAPs-21 and dCAPs-19, at genetic distances of 0.05 cM and 0.15 cM, respectively. The physical distance of this region was 19.6 kb. Three markers, InDel-19, dCAPs-2 and dCAPs-11, co-segregated with csgl3. There were two candidate genes in the region, Csa6M514860 and Csa6M514870. Quantitative real-time PCR showed that the expression of Csa6M514870 was higher in the tissues of 9930 than that of NCG157, and this was consistent with their phenotypic characters. Csa6M514870 is therefore postulated to be the candidate gene for the development of trichomes in cucumber. This study will facilitate marker-assisted selection (MAS) of the smooth plant trait in cucumber breeding and provide for future cloning of csgl3. 相似文献
7.
Studies on the regeneration-restore and karyotype of protoplast in Metarhizium anisopliae var. majus
Abstract: The characteristics and regeneration-restore of protoplasts and its karyotype of an insect pathological fungus, Metarhizium anisopliae var. majus were studied. Among the protoplasts, 25.3% were without a nucleus, and 74.7% contained a nucleus. Among the nucleus protoplasts, 53.6% contained a single nucleus. The regeneration-restore of protoplasts was of three distinct shapes. Considering the frequency of regeneration and the growing speed of the colony, 0.7 mol/l glucose was the optimum as osmotic stabilizer of culture medium in the regeneration-restore of the protoplasts. The chromosomal DNA molecules of M. anisopliae var. majus have been separated into seven bands by pulsed-field gel electrophoreses. Using the Schizosaccharomyces pombe chromosomes as size standard, the size of chromosomal DNA was estimated to be 1.1–6.5 Mb and its karyotype exhibited polytypism among strains. 相似文献
8.
l-Phenylalanyl-l-Glutamate-Stimulated, Chloride-Dependent Glutamate Binding Represents Glutamate Sequestration Mediated by an Exchange System 总被引:7,自引:6,他引:1
Markus Kessler Gene Petersen Hai Minh Vu Michel Baudry Gary Lynch 《Journal of neurochemistry》1987,48(4):1191-1200
Stimulation of glutamate binding by the dipeptide L-phenylalanyl-L-glutamate (Phe-Glu) was inhibited by the peptidase inhibitor bestatin, suggesting that the stimulation was caused by glutamate liberated from the dipeptide and not by the dipeptide itself. It further suggests that this form of glutamate binding should be reinterpreted as glutamate sequestration and that stimulation of binding both by dipeptides and after preincubation with high concentrations of glutamate is likely to be due to counterflow accumulation. Several other criteria indicate that most of glutamate binding stimulated by chloride represents glutamate sequestration: Binding is reduced when the osmolarity of the incubation medium is increased, when membranes incubated with [3H]glutamate are lysed before filtration, and when membranes are made permeable by transient exposure to saponin. Moreover, dissociation of bound glutamate after a 100-fold dilution of the incubation medium is accelerated about 50 times by the addition of glutamate to the dilution medium. This result would be anomalous if glutamate were bound to a receptor site; it suggests instead that glutamate is transported in and out of membrane vesicles by a transport system that preferentially mediates exchange between internal and external glutamate. Glutamate binding contains a component of glutamate sequestration even when measured in the absence of chloride. Sequestration is adequately abolished only after treating membranes with detergents; even extensive lysis, sonication, and freezing/thawing may be insufficient. 相似文献
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叶绿体中存在着与细胞分裂素(CTK)专一结合的蛋白质。这一蛋白与6-苄氨基嘌呤(6 BA)的亲和力很强,解离常数达3.7×10~(-8)mol/L。最大结合量为10.7 pmol 6 BA/mg蛋白,Seatchard分析表明只有一类结合位点。不同的叶绿体纯化步骤对CTK结合蛋白的活性有不同的影响,分离步骤少而快速的差速离心法可以得到具有较高结合活性的叶绿体。叶绿体经分离纯化后,低温保存时的结合活性较稳定,-20℃以下可以较长期保存。用EDTA预处理叶绿体,不降低CTK结合蛋白对6 BA的结合活性,而用高浓度的NaCl处理,可以使叶绿体结合6BA的能力明显下降。这说明EDTA不能使CTK结合蛋白从叶绿体膜系统表面解离,而高浓度NaCl则有这种可能性。 相似文献