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81.
82.
Jia-Xing Fang Da-Feng Chen Xia Shi Su-Fang Zhang Fu Liu Wei-Xing Shen Chun-Yan Jia Shen-Cheng Ma Zhen Zhang Xiang-Bo Kong 《植物分类学报:英文版》2023,61(3):498-505
Cuticular hydrocarbons of Cerambycidae species can function as signals for sex recognition. Little is known about the copulatory signals of the juniper bark borer Semanotus bifasciatus, a major economic threat to Platycladus orientalis Franco in China. Here, we investigated the cuticular hydrocarbons of both sexes of S. bifasciatus to determine the chemically mediated mating signals using the solid-phase microextraction (SPME) technique with carbowax/divinylbenzene fibers (CAR/DVB) and then analyzed by coupled gas chromatography-mass spectrometry (GC-MS). A series of aliphatic saturated straight-chain n-alkanes (n-C23 to n-C28), internally branched monomethylalkanes at carbons 3, 11, or 13, and dimethylalkanes were identified, which showed no qualitative differences in either sex and were similar in the samples with SPME fiber extraction and those with hexane extraction. The bioassay showed that 11-methylpentacosane (11-MeC25), 11-methylhexacosane (11-MeC26), and 11-methylheptacosane (11-MeC27) have sex-specific recognition functions that triggered more mating attempts at a female-specific ratio of 100:4:60 than at a male-specific ratio of 100:85:50. In addition, the female-specific ratio of 11-methylalkanes can elicit about 70% of male mating attempts within about 60 s, whereas live females elicit about 98% of male mating attempts within 25 s. The discrepancy in the initiation of mating attempts by synthetic mixtures and live females suggests that the methyl isomers 3-MeC25, 3-MeC27, and/or 11,15-diMeC27 may also be involved in the mating behavior of S. bifasciatus. These results suggest that 11-MeC25, 11-MeC26, and 11-MeC27 constitute the contact sex pheromone of S. bifasciatus, with the presence or absence of 11-MeC26 in particular playing an important role in mate recognition by males. 相似文献
83.
Jing‐Fang Guo Baosheng Wang Zhan‐Lin Liu Jian‐Feng Mao Xiao‐Ru Wang Wei Zhao 《植物分类学报:英文版》2023,61(1):143-156
Endemic species are important components of regional biodiversity and hold the key to understanding local adaptation and evolutionary processes that shape species distributions. This study investigated the biogeographic history of a relict conifer Pinus bungeana Zucc. ex Endl. confined to central China. We examined genetic diversity in P. bungeana using genotyping-by-sequencing and chloroplast and mitochondrial DNA markers. We performed spatial and temporal inference of recent genetic and demographic changes, and dissected the impacts of geography and environmental gradients on population differentiation. We then projected P. bungeana's risk of decline under future climates. We found extremely low nucleotide diversity (average π 0.0014), and strong population structure (global FST 0.234) even at regional scales, reflecting long-term isolation in small populations. The species experienced severe bottlenecks in the early Pliocene and continued to decline in the Pleistocene in the western distribution, whereas the east expanded recently. Local adaptation played a small (8%) but significant role in population diversity. Low genetic diversity in fragmented populations makes the species highly vulnerable to climate change, particularly in marginal and relict populations. We suggest that conservation efforts should focus on enhancing gene pool and population growth through assisted migration within each genetic cluster to reduce the risk of further genetic drift and extinction. 相似文献
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86.
天兰冰草染色体对小冰麦外植体再生能力的影响及基因的染色体定位 总被引:1,自引:1,他引:0
本文研究了天兰冰草(Agropyronintermedium2n=42)染色体导入小麦后对小冰麦外植体再生能力的影响,从而分析调控再生能力的基因所在天兰冰草染色体的定位。对异源八倍体小冰麦的研究表明,与天兰冰草强再生能力有关的基因主要分布在附加到中2的冰草染色体组上;对7个异附加系小冰麦的研究进一步表明,冰草强再生能力的性状由多基因调控,这些基因主要分布在附加到TAI-11、TAI-12、TAI-13的冰草染色体上。此外,小冰麦杂种F1的研究表明,在组织培养中同样能够表现出杂种优势。 相似文献
87.
Glutamate-induced swelling of cultured astrocytes is mediated by metabotropic glutamate receptor 总被引:1,自引:0,他引:1
The effects of glutamate and its agonists and antagonists on the swelling of cultured astrocytes were studied. Swelling of astrocytes was measured by [3H]-O-methyl-D-glucose uptake. Glutamate at 0.5, 1 and 10mmol/L and irons-l-aminocyclopentane-1,3-dicarboxylic acid (trans-ACPD), a metabotropic glutamate receptor (mGluR) agonist, at 1 mmol/L caused a significant increase in astrocytic volume, whereas alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid (AMPA) was not effective. L-2-amino-3-phosphonopropionic acid (L-AP3), an antagonist of mGluR, blocked the astrocytic swelling induced by trans-ACPD or glutamate. In Ca2+-free condition, glutamate was no longer effective. Swelling of astrocytes induced by glutamate was not blocked by CdCl2 at 20 μmol/L, but significantly reduced by CdCl2 at 300 μmol/L and dantrolene at 30 μmol/L. These findings indicate that mGluR activation results in astrocytic swelling and both extracellular calcium and internal calcium stores play important roles in the genes 相似文献
88.
David A. Randolph James W. Verbsky Liping Yang Yifu Fang Razqallah Hakem Larry E. Fields 《Transgenic research》1996,5(6):413-420
Gene targeting by double homologous recombination in murine embryonic stem (ES) cells is a powerful tool used to study the cellular consequences of specific genetic mutations. A typical targeting construct consists of a neomycin phosphotransferase (neo) gene flanked by genomic DNA fragments that are homologous to sequences in the target chromosomal locus. Homologous DNA fragments are typically cloned from a murine genomic DNA library. Here we describe an alternative approach whereby the inducible nitric oxide synthase (NOS2) gene locus is partially mapped and homologous DNA sequences obtained using a long-range PCR method. A 7 kb NOS2 amplicon is used to construct a targeting vector where theneo gene is flanked by PCR-derived homologous DNA sequences. The vector also includes a thymidine kinase (tk) negative-selectable marker gene. Following transfection into ES cells, the PCR-based targeting vector undergoes efficient homologous recombination into the NOS2 locus. Thus, PCR-based gene targeting can be a valuable alternative to the conventional cloning approach. It expedites the acquisition of homologous genomic DNA sequences and simplifies the construction of targeting plasmids by making use of defined cloning sites. This approach should result in substantial time and cost savings for appropriate homologous recombination projects. 相似文献
89.
Esculentoside A (EsA) is a saponin isolated from the roots of Phytolacca esculenta. Previous experiments have shown that it has strong anti-inflammatory effects. Tumour necrosis factor (TNF) is a very important inflammatory mediator. It is known that there are two types of TNF-TNFalpha is from macrophages/monocytes and TNFbeta is from activated lymphocytes. In order to study the mechanism of the anti-inflammatory effect of EsA, it was determined whether TNFalpha production from human peripheral monocytes was altered by EsA under lipopolysaccharide (LPS)-stimulated conditions. EsA was found to decrease TNFalpha production in a dose-dependent manner at concentrations higher than 1 mumol/l EsA. Recent studies have shown that EsA has a curative effect on chocolate cyst and other inflammatory diseases. Our previous studies have shown that EsA could reduce the release of platelet activating factor (PAF) from rat macrophages, and inhibit interleukin-1 and interleukin-6 production from routine macrophages. The reducing effects of EsA on the release of TNFalpha, IL-1, IL-6 and PAF may explain its anti-inflammatory effect. 相似文献
90.
采后大蒜鳞茎的生理生化变化及其贮藏技术 总被引:2,自引:0,他引:2
采后大蒜鳞茎的生理生化变化及其贮藏技术刘淑娴,李月标,陈芳,张东林,蒋跃明(中国科学院华南植物研究所,广州510650)摘要大蒜鳞茎在室温下贮藏2个月后,胚芽开始生长.随着胚芽生长,呼吸速率、蛋白质和维生素C含量逐渐增高;而可溶性糖和干物质含量下降。... 相似文献