955 resultados para Plutella xylostella (Linnaeus 1758)
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采用活体注射秋水仙碱制备鱼类肾细胞染色体、PHA肌肉注射制备肾细胞染色体和鱼类早期胚胎制备染色体等多种方法。以空气干燥法制片Giemsa染色,对鲻鱼Mugil cephalus Linnaeus、真鲷Pagrosomus major(Temminck et Schlegel)、黑鲷Sparus macrocephalus(Basilewsky)、黑鮶Sebastes schlegeli (Hilgendorf)、石鲽Kareius bicoloratus (Basilewsky)、牙鲆Paralichthys olivaceus (Temminck et Schlegel)等分属四目、五科的六种海产鱼的染色体组型进行了考察和分析。研究结果表明:1、一般活体注射秋水仙碱制备海产鱼肾细胞染色体方法的有丝分裂指数虽然略低于PHA制备肾细胞染色体方法的有丝分裂指数。但它是最快最简便且很有效的方法,利用鱼类早期胚胎制备海产鱼染色体标本的方法也很有效,但要受到生物季节的限制。2、通过对六种海产鱼染色体组型分析得到,鲻鱼为48条端部着丝点染色体;真鲷的二倍体2n=48,有1对亚端部着丝点染色体。其余全部为端部着丝点染色体;黑鲷的二倍体2n=48。有3对中部着丝点染色体。2对亚中部着丝点染色体,其余全部为端部着丝点染色体。黑鮶的二倍体2n=48,有1对中部着丝点染色体,其余全部为端部着丝点染色体,石鲽的二倍体2n=48。全部为端部着丝点染色体;牙鲆的二倍体2n=48,全部为端部着丝点染色体。本文还对鱼类染色体的多态现象以及染色与进化的关系进行了讨论。
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近年来,在“清洁生产”、“生态养殖”以及“生物修复”理论的指导下,在贝类稚贝培育和成贝养殖过程中实施贝藻混合模式,已经成为国内外学者研究的热点之一。本文在封闭水体中进行了龙须菜(Gracilaria lemaneiformis Weber-van Bosse)和文蛤(Meretrix meretrix Linnaeus)稚贝以及成贝的混养实验,初步探索了混养系统中的互利机制,监测了水体中理化因子和生物因子的变化规律,测定了养殖生物的生长情况及营养成分,构建了混养系统中贝藻混养的合理模式。并且采用新技术-T-RFLP监测了养殖水体中细菌的动态变化。主要研究成果如下: 1. 在龙须菜与稚贝混养实验中,平均水温为17.5±3.2℃。研究结果表明较低的温度抑制了龙须菜的生长,总平均日生长率最高为0.81%/d,小于与成贝混养实验的最高特定生长率1.79%/d。养殖水体中氨氮和磷酸盐是最主要的无机污染物,而龙须菜对养殖水体营养盐的去除作用显著, 35天后混养系统中养殖水体的氨氮和磷酸盐平均浓度较单养系统低43.37μmol/L、1.23μmol/L,分别相差95.06%、94.85%。 2. 在龙须菜与成贝混养实验中,平均水温为23.1±2.3℃,适合龙须菜的生长,结果表明龙须菜对氨氮和亚硝氮的吸收高达86%~98%,对无机磷的吸收可达99%,养殖生物的生长情况良好,养殖生物体内的营养成分要好于单养系统中的养殖生物。对于氨基酸总含量,加入龙须菜的养殖系统中文蛤体内的氨基酸总含量要比单养系统中文蛤体内氨基酸总含量高26.0mg/g,高出后者5.01%。引入龙须菜在一定程度上可以抑制异养细菌和致病性弧菌的生长,相对抑制率达到77.75%。在本实验中,尽管龙须菜可以抑制异养细菌的生长,但如果引入过多会导致嗜江蓠细菌过度增加,可能反而会破坏原有的微生态平衡。 3. 采用T-RFLP技术对养殖水体中的总细菌群落进行了分析,摸索出合理的方法和步骤,通过聚类分析将养殖水体中细菌群落分为两个群落,并且认为在养殖水体中,微生物群落的变化是及其复杂的,第六周时两个群落变化不一致。并且相对来说,龙须菜的引入可能会对某些群落造成抑制,但也可能会对其它细菌群落起到促进作用。 4. 稚贝和成贝分别与龙须菜的混养实验结果表明,在养殖系统中引入龙须菜可以改善养殖环境,龙须菜和文蛤的适宜混合比例为1:1能取得较好的生态效应。
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本文研究了典型有毒赤潮藻——亚历山大藻(Alexandrium)对海湾扇贝(Argopecten irradians Lamarck)、文蛤(Meretrix meretrix Linnaeus)和太平洋牡蛎(Ostrea gigas Thunberg)受精卵孵化的影响和致毒机制以及对蒙古裸腹溞(Moina mongolica Daday)生命活动的影响。此外,还针对我国赤潮发生特点,模拟研究了我国东海大规模赤潮对菲律宾蛤仔(Ruditapes philippinarum (Adams et Reeve))受精卵孵化和蒙古裸腹溞种群数量的影响。 结果发现:8株产PSP毒素的亚历山大藻:塔玛亚历山大藻( ATHK, AT5-1, AT5-3, ATCI02, ATCI03),链状亚历山大藻, A. lusitanicum、微小亚历山大藻和2株不产PSP毒素的相关亚历山藻(AC-1, AS-1)对海湾扇贝受精卵的孵化均有显著抑制作用,说明在亚历山大藻属中,这种抑制作用具有一定的普遍性,并与PSP毒素的产生无直接关系,表明存在非PSP毒素的其它毒性物质。一种PSP标准毒素STX也没有这种抑制作用,进一步证明该抑制作用与PSP毒素不直接相关。 相关亚历山大藻AC-1对海湾扇贝、文蛤和太平洋牡蛎受精卵孵化的有显著的毒害作用,其藻液、重悬液、去藻液和内容物均显著影响受精卵的孵化。相关亚历山大藻AC-1对海湾扇贝、文蛤和太平洋牡蛎担轮幼虫细胞的超微结构有显著破坏作用,破坏膜结构和胞内结构,影响细胞内的功能器官如溶酶体的稳定性,使卵黄颗粒萎缩变形;对文蛤和太平洋牡蛎的受精卵显示出极强的毒害作用: 3000cells•ml-1时,使二者胚胎完全溶掉消失;在2000cells•ml-1的藻液中培养2h后,担轮幼虫的外膜发生溶解,整个幼体呈葡萄串样。相关亚历山大藻AC-1产生的这种毒性物质可能对贝类胚胎细胞的结构和功能有影响。 亚历山大藻对蒙古裸腹溞的毒性效应与不同藻种/藻株密切有关:塔玛亚历山大藻(AT-6, ATCI02)、链状亚历山大藻、A. lusitanicum和微小亚历山大藻不影响蒙古裸腹溞的存活,而塔玛亚历山大藻(ATHK、ATCI03和AT5-1)和相关亚历山大藻(AC-1, AS-1)有显著影响。蒙古裸腹溞能摄食塔玛亚历山大藻(AT-6, ATHK, ATCI02, ATCI03, AT5-1),链状亚历山大藻, A. lusitanicum和微小亚历山大藻,很少或基本不摄食相关亚历山大藻。亚历山大藻影响蒙古裸腹溞的RNA/DNA比值和蛋白质含量以及Na+,K+-ATP酶活性。相关亚历山大藻AC-1对蒙古裸腹溞的存活有极强的毒性作用,藻液、重悬液、内容物和碎片均有显著影响;即使与3×106cells•ml-1小球藻混合,10和50cells•ml-1的相关亚历山大藻AC-1仍能使蒙古裸腹溞的产幼数和存活时间显著下降。亚历山大藻对蒙古裸腹溞生命活动的影响不仅与PSP毒素有关,还与非PSP毒素有关;蒙古裸腹溞可能也是研究有害藻急性和慢性毒性的一种理想生物。 应用菲律宾蛤仔胚胎和蒙古裸腹溞评价我国东海特大规模赤潮对海洋生物资源的潜在危害时发现:单种链状亚历山大藻对菲律宾蛤仔受精卵的孵化和蒙古裸腹溞的种群增长均有显著不利影响;单种东海原甲藻(1~10×104cells•ml-1)对菲律宾蛤仔受精卵的孵化没有影响;较低密度的东海原甲藻能维持蒙古裸腹溞(2~5×104cells•ml-1)的种群增长;较高密度的东海原甲藻对蒙古裸腹溞(10×104cells•ml-1)种群有显著的抑制作用。两种藻以赤潮密度混合后,适当密度的东海原甲藻能在一定程度上减轻链状亚历山大藻对菲律宾蛤仔受精卵和蒙古裸腹溞的毒性。可见,东海连年爆发的大规模赤潮不仅对浮游生态系统有不利影响,若同时爆发亚历山大藻赤潮,则对海洋浮游生态系统和贝类资源的恢复产生更加不利的影响。
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恶性肿瘤是严重威胁人类健康的疾病,目前的抗肿瘤药物虽然具有一定疗效,但存在选择性差、毒副作用大等缺点,药物治疗期待着新的突破。因此,寻找高效低毒的抗肿瘤药物已经成为当前肿瘤研究的重要内容。传统抗肿瘤天然药物的来源局限在陆地,近年来在海洋来源的具有抗肿瘤活性物质的开发上取得了很多成果,获得了多种高活性、毒副作用小、作用机制新颖的活性化合物,为新型抗肿瘤药物的研发提供了新思路。 本研究采用硫酸铵分级沉淀、弱阳离子交换层析、疏水层析、强阴离子交换层析等分离技术,结合MTT活性追踪方法,从海洋软体动物文蛤体液中纯化得到单一蛋白组份MML,SDS-PAGE检测其分子量约为40kD。该蛋白在体外具有显著的抗人肝癌细胞BEL-7402的活性,其IC50达到52µg/mL。相差显微镜下观察发现,MML起效较快,细胞处理半小时后,形态开始发生改变,细胞膜逐渐与胞内物质分离,最终形成明显的空泡状结构。 为进一步研究MML的作用方式,分别从细胞膜毒性、细胞周期阻滞及诱导肿瘤细胞凋亡的角度开展了相关研究。在细胞膜毒性方面,采用扫描电镜观察、Hoechst33342/ PI双染色和乳酸脱氢酶漏出率检测的方法,初步证明了MML对BEL-7402具有细胞膜毒性。结合流式细胞仪、微管蛋白免疫荧光检测技术,研究了MML作用后的细胞周期及微管蛋白的变化情况,结果发现MML的抗肿瘤作用方式可能是通过改变肿瘤细胞膜通透性,进而破坏微管蛋白聚合、阻滞细胞周期,产生抑制肿瘤细胞增殖的活性。DNA Ladder琼脂糖凝胶电泳分析发现,MML作用后的细胞出现一定程度的凋亡,这种凋亡现象的产生是由于MML的直接诱导,还是间接作用产生,尚有待于深入研究。
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Silicateins, members of the cathepsin L family, are enzymes that have been shown to be involved in the biosynthesis/condensation of biosilica in spicules from Demospongiae (phylum Porifera), e. g. Tethya aurantium and Suberites domuncula. The class Hexactinellida also forms spicules from this inorganic material. This class of sponges includes species that form the largest biogenic silica structures on earth. The giant basal spicules from the hexactinellids Monorhaphis chuni and Monorhaphis intermedia can reach lengths of up to 3 m and diameters of 10 mm. The giant spicules as well as the tauactines consist of a biosilica shell that surrounds the axial canal, which harbours the axial filament, in regular concentric, lamellar layers, suggesting an appositional growth of the spicules. The lamellae contain 27 kDa proteins, which undergo post-translational modification (phosphorylation), while total spicule extracts contain additional 70 kDa proteins. The 27 kDa proteins cross-reacted with anti-silicatein antibodies. The extracts of spicules from the hexactinellid Monorhaphis displayed proteolytic activity like the silicateins from the demosponge S. domuncula. Since the proteolytic activity in spicule extracts from both classes of sponge could be sensitively inhibited by E-64 (a specific cysteine proteinase inhibitor), we used a labelled E-64 sample as a probe to identify the protein that bound to this inhibitor on a blot. The experiments revealed that the labelled E-64 selectively recognized the 27 kDa protein. Our data strongly suggest that silicatein(-related) molecules are also present in Hexactinellida. These new results are considered to also be of impact for applied biotechnological studies.
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Karyotype and chromosomal location of the major ribosomal RNA genes were studied in the hard clam (Mercenaria mercenaria Linnaeus) using fluorescence in situ hybridization (FISH). Metaphase chromosomes were obtained from early embryos. Internal transcribed spacers (ITS) between major RNA genes were amplified and used as FISH probes. The probes were labeled with digoxigenin-11-dUTP by polymerase chain reaction and detected with fluorescein-labeled anti-digoxigenin antibodies. FISH with the ITS probes produced two to four signals per nucleus or metaphase. M. mercenaria had a haploid number of 19 chromosomes with a karyotype of seven metacentric, four metacentric or submetacentric, seven submetacentric, and one submetacentric or subtelocentric chromosomes (7M + 4M/SM + 7SM + 1SM/ST). Two ITS loci were observed: one located near the centromere on the long arm of Chromosome 10 and the other at the telomere of the short arm of Chromosome 12. FISH signals on Chromosome 10 are strong and consistent, while signals on Chromosome 12 are variable. This study provides the first karyotype and chromosomal assignment of the major RNA genes in M. mercenaria. Similar studies in a wide range of species are needed to understand the role of chromosomal changes in bivalve evolution.
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The mixture of the feces and urine of the red fox (Vulpes vulpes Linnaeus) was used to increase the perception of predation risk of plateau pikas (Ochotona curzoniae Hodgson) in the field. The influence of the predation risk on the reproduction and behavior of plateau pikas was examined through comparing reproductive characteristics and five different kinds of behavior between treatment and control plots. The results showed that 1) the body weight of the pikas was not significantly different between treatment and control plots. 2) The reproductive period of the pikas extended from March to later August in both treatment and control plots. The pregnant ratio, developed testes ratio, reproductive success and sex ratio of the pikas were not significantly different between the treatment and control plots. 3) The pikas increased their observing and calling frequencies and decreased their moving and feeding frequencies when exposed to red fox's feces and urine. 4) The increased red fox's feces and urine had no influence on the behavior of the pikas when the number of their natural enemies increased; the pikas obviously increased the observing frequencies and sharply decreased the calling frequency so as to decrease the direct predation risk. 5) There were no significantly behavioral differences between males and females as well as between adults and young. 6) The results reject the hypothesis 1 that the red fox's feces and urine as indirect predation risk suppresses the reproduction of the pikas and support the hypothesis 2 that the pikas can make decision by changing behavior to avoid the predation risk they encountered whenever.
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During preparation of the account of Stellaria L (Caryophyllaceae) for the Flora of China, Volume 6, it was noticed that two names are illegitimate later homonyms: Stellaria arenaria Maximowicz, non Linnaeus, and Stellaria pilosa Franchet, non Dulac. Therefore, the following ne names (nomina nova) are provided here: Stellaria arenarioides Shi L. Chen, Rabeler & Turland and Stellaria pilosoides Shi L. Chen, Rabeler & Turland.
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The dissertation focuses on the petrology, geochemistry of the volcanic rocks in east Tibet and southeast Yunnan. It lucubrates the Magmatic process, forming mechanism and the possible tectonic settings of the volcanic rocks. The volcanic rocks of Nangqen basin in east Tibet, Qinghai province are mainly Cenozoic intermediate-acid shoshonites. The rocks are LREE enriched and the LREE/HREE = 3~34; (La/Yb)_N = 18.17-53.59, and ΣREE 222~1260μg/g. There are no Eu anomaly, and Nb, Ta, Zr, Hf, Ti are markedly depleted. The isotopic composition is ~(87)Sr/~(86)Sr = 0.70497~0.70614, ~(206)Pb/~(204)Pb = 18.622~18.974, ~(208)Pb/~(204)Pb = 38.431~38.996, ~(207)Pb/~(204)Pb = 15.511~15.613, respectively. K-Ar age of the whole rocks and the single mineral are between 32.0-36.5Ma. Based on the trace elements and isotopic elements, we get the conclusion that the partial melting is one of the dominated forming mechanisms for the volcanic rocks in Naneqen basin. The magma did not experience the crustal contamination en route to the surface; however, the complex mixture took place in the upper mantle before the melt was formed. There are at least two kinds of mixed sources that can be identified. The basalt in southeast Yunnan province is studied. They are distributed in Maguan, Tongguan, and Pingbian County, which is located on the both sides of the Red River belt, and the ultrabasic xenolith are cursory introduced. The volcanic rocks belongs to the alkali series, which can be subdivided into trachybasalt and basanite(Ol normal molecule >5). The volcanic rocks are characteristics by high Ti and low Mg#. According to the magma calculation model, the original rocks of the basalt in southeast Yunnan province are Spinel Lherzolite in Tongguan, Garnet Lherzolite in Pingbian and Maguan, while Togguan undergoes 2-5 percent and percent of partial melting, whereas volcanism in Maguan and Pingbian was so complex to calculate. The fractional crystallization took place during the magma evoltion in southeast Yunnan. The basalt is enriched in LREE with LREE/HREE=9.23-20.19. All of the trace elements display weak Nb, Ta peak, and the depletion of Zr, Hf and Ti in Maguan and pingbian represent the presence of Garnet in the source. The composition of the isotope ratio are ~(87)Sr/~(86)Sr = 0.70333-0.70427, ~(143)Nd/~(144)Nd = 0.512769-0.512940, ~(206)Pb/~(204)Pb = 18.104-18.424, ~(207)Pb/~(204)Pb = 15.483 -15.527; ~(208)Pb/~(204)Pb = 37.938-38.560, respectively, which shows the characteristics of the HIMU type OIB. The volcanic rocks of the southwest Yunnan are derived from the enriched, OIB type mantle sources by synthesizing all the data from trace and isotope elements. It is similar to that of the volcanic rocks in Hawaii, a typical kind of the mixtures of the recycled oceanic crust plume and depleted asthenosphere. To sum up, the volcanic rocks in southeast Yunnan are formed by the intraplate hotpot volcanism.