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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.
四川大头茶净光合作用生理生态的初步研究 总被引:6,自引:0,他引:6
为了探讨重要生理生态因子在自然条件下对四川大头茶净光合作用(p_n)的影响,本文采用改良半叶法测定净光合作用的日变化和年变化。结果表明:春夏秋三季晴天p_n日变化呈双峰曲线型,即上,下午各出现一次P_n高峰,蜂谷则是P_n中午降低现象。冬季晴天P_n呈单峰曲线型。5月至11月P_n平均值为9.00mg·dm~(-2)·h~(-1)最高值23.44mg·dm~(-2)·h~(-1)出现在8月底。 一定程度上,P_n年变化曲线与温度年变化曲线相似,可以明显地区分为三部分。第一部分是从1月至5月,P_n随着温度的逐步上升而逐步升高。5月至10月为第二部分,此间P_n波动较大。10月至12月为第三部分,P_n随着逐步下降的温度而逐步降低。P_n季节变化显著,与植物生长、发育节奏相关。 温度和光照强度是影响P_n最重要的生态因子,相对湿度,叶绿素含量和SLW对P_n影响不大。温度与P_n呈一不对称钟形曲线,P_n的最低温度是4—5℃,最适温度是25—30℃,或稍高于30℃,最高温度则大于30℃。P_n的光饱和点在70,000lx左右,光补偿点约为3,000lx.在最适温度(25—30℃)范围内,P_n主要由光强所控制,并与光强呈正相关,一旦低于或超过最适温度,P_n则主要由温度所决定,与温度呈正相关。 遮阴实验表明,四川大头茶是具相当耐阴能力的阳性植物。 相似文献
9.
5—羟色胺对大鼠下丘脑脑薄片室旁核神经元自发电活动的作用 总被引:2,自引:1,他引:1
在20个下丘脑脑片上,用玻璃微电极细胞外记录了46个室旁核神经元的自发放电单位,观察了5-羟色胺对它们的作用。当薄片用含5-羟色胺(10~(-6)mol/L)的人工脑脊液灌流后,有16个单位放电频率明显增加,反应的潜伏期为1.21±1.21 min。这种反应可被5-羟色胺的阻断剂噻庚啶所阻断。3个单位放电频率明显减少,27个单位无明显反应。实验结果表明约1/3的下丘脑室旁核神经元能被5-羟色胺所激活。 相似文献
10.
荔枝蝽象卵寄生蜂——平腹小蜂体外培育研究 总被引:3,自引:0,他引:3
本文报道用人造寄主卵繁殖平腹小蜂Anastatus japonicus Ashmead***成功的结果.筛选出最佳卵壳材料为32—36μm的聚丙烯膜,培养基为柞蚕蛹血淋巴44.4%、10%麦乳精33.3%、鸡蛋黄11.1%、尼氏盐11.1%.体外连代培养平腹小蜂的结果表明,除蛹化率(72—83%)外,各代间在寄生率(40—44%)、孵化率(94—96%)、羽化率(91—96%)、展翅率(97—99%)方面无明显的差别,且人造卵育出的各代蜂在身体大小、寿命及繁殖力方面均与柞蚕卵育出蜂基本相似或优于柞蚕卵育出蜂.筛选出的人工培养基的氨基酸种类与蓖麻蚕卵和柞蚕卵相同,但量上差异比较明显.本文还报道了平腹小蜂在人造寄主卵上的产卵过程. 相似文献