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Four distinct viruses with double-stranded DNA are known to replicate in Chlorella-like algae symbiotic with hydras and paramecia. An attempt was made to infect a number of cultured Chlorella strains derived from invertebrate hosts with these viruses. One of the viruses, PBCV-1, replicated in two of the algal strains. Restriction endonuclease analysis of the viral DNA showed that the infectious progeny virus was identical to the input virus; thus, Koch's postulates were fulfilled. Viral infection of the two Chlorella strains has allowed the large-scale production of a eukaryotic algal virus and the development of a plaque assay for the virus. 相似文献
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外源共生基因对紫云英根瘤菌共生效率的影响 总被引：2，自引：0，他引：2
将豌豆根瘤菌共生质粒pJB5JI、含紫云英根瘤菌共生基因的重组质粒pRaZ15及含苜蓿根瘤菌共生基因的重组质粒pRmSL26导入紫云英根瘤菌野生型菌株7653R，然后对3种转移接合子的共生固氮效率进行了比较全面的测定。结果表明：转移接合子7653R（pJB5JI）的共生固氮能力较出发菌株7653R大幅度提高，而且表现出较高的竞争结瘤能力，转移接合子7653R（pRmSL26）在固氮酶活性、植物干重及结瘤数方面亦显著高于对照菌株7653R；转移接合子7653R（pRaZ15）虽然在固氮酶活性及植物干重方面没有发现显著性差异，但结瘤数显著减少。 相似文献
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Genome-wide characterization of miRNA and siRNA pathways in the parasitoid wasp Pteromalus puparum 
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下载免费PDF全文 XIAO Shan FANG Qi LIU Ming-ming ZHANG Jiao WANG Bei-bei YAN Zhi-chao WANG Fang David W. STANLEY YE Gong-yin 《农业科学学报》2022,21(4):1106-1115
microRNAs (miRNAs) and small interfering RNAs (siRNAs) are small non-coding RNAs (ncRNAs) that trigger RNA interference (RNAi) in eukaryotic organisms. The biogenesis pathways for these ncRNAs are well established in Drosophila melanogaster, Aedes aegypti, Bombyx mori and other insects, but lacking in hymenopteran species, particularly in parasitoid wasps. Pteromalus puparum is a parasitoid of pupal butterflies. This study identified and analyzed two pathways by interrogating the P. puparum genome. All core genes of the two pathways are present in the genome as a single copy, except for two genes in the siRNA pathway, R2D2 (two copies) and Argonaute-2 (three). Conserved domain analyses showed the protein structures in P. puparum were similar to cognate proteins in other insect species. Phylogenetic analyses of hymenopteran Dicer and Argonaute genes suggested that the siRNA pathway-related genes evolved faster than those in the miRNA pathway. The study found a decelerated evolution rate of P. puparum Dicer-2 with respect to Dicer-1, which was contrary to other hymenopterans. Expression analyses revealed high mRNA levels for all miRNA pathway genes in P. puparum adults and the siRNA related genes were expressed in different patterns. The findings add valuable new knowledge of the miRNA and siRNA pathways and their regulatory actions in parasitoid wasps. 相似文献
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植物MADS-box基因的研究进展 总被引：5，自引：0，他引：5
MADS-box基因是一类调控植物生长发育的关键基因,散布在整个植物基因组中.迄今,植物中已发现数以百计的MADS-box基因.多数MADS-box基因在植物生殖发育过程中起重要作用,同时也参与调节营养生长、子房发育、种皮发育、根的形成、胚形态建成和共生诱导等. 相似文献
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溶瘤病毒通过感染癌细胞,引起病毒性细胞病变并诱发宿主抗肿瘤免疫反应,从而选择性感染和杀死癌细胞。美国食品药品监督管理局(FDA)和欧洲药物管理局(EMA)最近批准了世界上第一个用于治疗恶性黑色素瘤的溶瘤病毒制剂,命名为Imlygic。Imlygic为表达人粒细胞-巨噬细胞集落刺激因子(GM-CSF) 的单纯疱疹病毒I型(HSV-1)活病毒颗粒,经直接注射入肿瘤组织引起肿瘤细胞裂解和机体抗肿瘤免疫双重效应。除了HSV-1外,尚有许多不同类型的病毒已经进入临床试验,评估其生物安全性和抗肿瘤疗效。这些正在临床试验的溶瘤病毒包括腺病毒、痘病毒、麻疹病毒和呼肠孤病毒等。治疗的肿瘤包括卵巢癌、腹膜癌、肝癌、胶质瘤和黑色素瘤等。目前,溶瘤病毒治疗肿瘤的临床试验约有67项,一些临床试验已经取得了有希望的结果,从而进展到第三期临床试验。该文重点讨论目前正在临床试验中用于治疗各类癌症的溶瘤病毒,并讨论这些溶瘤病毒作为一类新的癌症治疗药物的机遇和挑战。 相似文献
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【目的】探明转地放蜂过程中常见蜜蜂病毒和寄生虫的流行规律,及不同地区工蜂肠道中两种主要共生菌Gilliamella apicola和Snodgrassella alvi的变化情况。【方法】在转地放蜂过程中,对同一意大利蜜蜂(Apis mellifera ligustica)蜂场的固定蜂群连续取样,采用RT-PCR方法检测蜂群中病毒和寄生虫的感染情况,使用SPSS 17.0软件对不同地区、不同季节样本的病毒和寄生虫感染率进行卡方检验。以蜜蜂β-actin为内参基因,对不同地区样本中的共生菌G.apicola和S.alvi进行荧光定量PCR分析,检测转地过程中工蜂肠道中这两种细菌的变化情况,并采用Kendall Rank相关系数对病原物感染率和共生菌含量进行相关性分析。【结果】转地放蜂7个地区的样本中,仅检测出以色列急性麻痹病毒(IAPV)、黑蜂王台病毒(BQCV)和蜜蜂残翅病毒(DWV)3种蜜蜂病毒。其中IAPV和BQCV在所有地区均有检出且感染率较高,不同地区之间感染率差异显著;DWV感染率相对较低,不同地区之间感染率差异极显著。西方蜜蜂微孢子虫(Nosema apis)在各地区样本中均未检出,东方蜜蜂微孢子虫(Nosema ceranae)在4个地区的样本中检出,且不同地区间感染率差异极显著,熊蜂微孢子虫(Nosema bombi)在各个地区均有检出,不同地区间感染率差异显著;季节性差异分析表明,IAPV在不同季节的感染率差异不显著,而BQCV、DWV、N.ceranae和N.bombi在不同季节的感染率差异显著,且春夏季的感染率普遍高于秋冬季;不同转地地区的工蜂肠道内均含有共生菌G.apicola和S.alvi,且两种共生菌含量在不同地区间均差异极显著;相关性分析表明,S.alvi和IAPV之间呈显著负相关作用。【结论】转地蜂场工蜂病原微生物的检测结果表明IAPV、BQCV、DWV和微孢子虫在蜂群中普遍存在;蜜蜂病原物的感染率和肠道共生菌的含量在不同地理区域间差异显著;部分病原物与肠道共生菌间呈显著负相关关系;转地放蜂方式对蜜蜂的健康状况有一定影响。 相似文献
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Giraud E Moulin L Vallenet D Barbe V Cytryn E Avarre JC Jaubert M Simon D Cartieaux F Prin Y Bena G Hannibal L Fardoux J Kojadinovic M Vuillet L Lajus A Cruveiller S Rouy Z Mangenot S Segurens B Dossat C Franck WL Chang WS Saunders E Bruce D Richardson P Normand P Dreyfus B Pignol D Stacey G Emerich D Verméglio A Médigue C Sadowsky M 《Science (New York, N.Y.)》2007,316(5829):1307-1312
Leguminous plants (such as peas and soybeans) and rhizobial soil bacteria are symbiotic partners that communicate through molecular signaling pathways, resulting in the formation of nodules on legume roots and occasionally stems that house nitrogen-fixing bacteria. Nodule formation has been assumed to be exclusively initiated by the binding of bacterial, host-specific lipochito-oligosaccharidic Nod factors, encoded by the nodABC genes, to kinase-like receptors of the plant. Here we show by complete genome sequencing of two symbiotic, photosynthetic, Bradyrhizobium strains, BTAi1 and ORS278, that canonical nodABC genes and typical lipochito-oligosaccharidic Nod factors are not required for symbiosis in some legumes. Mutational analyses indicated that these unique rhizobia use an alternative pathway to initiate symbioses, where a purine derivative may play a key role in triggering nodule formation. 相似文献
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为建立水稻-根瘤菌共生固氮体系,将百脉根共生信号转导途径中的4个功能基因(LHK1、NSP1、NSP2和NIN)转入水稻,获得稳定转化的转基因水稻,并初步检测转基因水稻的表型和转录组水平上的差异。根瘤菌感染试验结果显示,根瘤菌侵染对照(转入空载体)和转基因水稻的根毛和表皮的比率没有显著变化,但接种根瘤菌14d后,对照与转基因水稻的侧根原基数有显著差异,转共生基因水稻的侧根原基明显增多。利用水稻cDNA芯片,检测转基因水稻组与对照组在接种根瘤菌7d和不接种根瘤菌条件下根的转录组变化,结果显示,转基因组与对照组水稻在植物防御反应、激素信号转导途径相关基因均有差异性表达,表明豆科共生基因影响了水稻对根瘤菌的反应。 相似文献
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为研究西北干旱地区豆科植物柠条锦鸡儿(Caragana korshinskii)根瘤菌的系统发育地位及共生基因多样性,对从甘肃省分离得到的菌株进行16SrRNA PCR-RFLP和序列分析,构建系统发育树,确定其分类地位,并通过分析共生基因nodA和nifH,确定种群共生类型。结果表明:从柠条根瘤内分离到64株菌,共有7个PCR-RFLP 16SrRNA基因型,主要归属于Ensifer(占分离总数43.8%)、Mesorhizobium(31.2%)、Rhizobium(25%),其中,Ensifer为主要类群,约占34.4%。共生基因nodA和nifH与Ensifer和Mesorhizobium模式菌株同源性较高,与16SrRNA基因确定的根瘤菌分类地位相比,发现部分共生基因与16S rRNA基因确定的分类地位不同,揭示了共生基因横向转移现象的发生。 相似文献
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Rho家族蛋白是一类含有GTPase结构域的高度保守蛋白的总称,它是真核生物中Ras超家族主要成员之一。通过同源比对以及RACE等技术从丛枝菌根真菌（Rhizophagus irregularis）DAOM197198中分离到了3个Rho家族小G蛋白。通过与其他真菌Rho蛋白家族成员进行系统进化分析,结果表明,所分离到的RiCDC42,RiRac1,RiRho1属于高度保守的Rho蛋白家族成员;利用实时荧光定量PCR方法对这3个基因在前共生阶段和共生阶段的表达模式进行分析,结果发现RiRho1在萌发孢子中的表达量最高,而在共生时期表达下调,RiRac1和RiCDC42基因在共生时期的表达量比共生前期高。此外,本研究还利用酵母CDC42,Rho1温度敏感性突变株,稻瘟病菌ΔMgCDC42突变株以及HIGS技术对Rhizophagus irregularis Rho蛋白家族成员进行进一步研究。结果显示,RiRho1与RiCDC42基因能够互补酵母Rho1与CDC42温度敏感型表型;对RiCDC42与RiRac1进行HIGS时,Rhizophagus irregularis 丛枝发生明显的降解;RiCDC42基因能够互补稻瘟病菌ΔMgCDC42突变体部分表型,但不同的是互补菌株不产黑色素。由此推测Rho蛋白家族成员可能在丛枝菌根真菌共生关系建立的过程中具有重要的作用。 相似文献
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A common onc gene sequence transduced by avian carcinoma virus MH2 and by murine sarcoma virus 3611 总被引：17，自引：0，他引：17
N C Kan C S Flordellis G E Mark P H Duesberg T S Papas 《Science (New York, N.Y.)》1984,223(4638):813-816
A common cellular sequence was independently transduced by avian carcinoma virus MH2 (v-mht) and murine sarcoma virus (MSV) 3611 (v-raf). Comparison of the nucleotide sequences of v-mht and v-raf revealed a region of homology that extends over 969 nucleotides. The homology between the corresponding amino acids was about 95 percent with only 19 of 323 amino acids being different. With this example, 5 of the 19 known different viral onc genes have been observed in viruses of different taxonomic groups. These data indicate that (i) the number of cellular proto-onc genes is limited because, like other viruses of different taxonomic groups, MH2 and MSV 3611 have transduced the same onc gene-specific sequences from different cell species and (ii) that specific deletion and linkage of the same proto-onc sequences to different viral vector elements affect the oncogenic potential of the resulting viruses. The difference in transformation capabilities of MH2 and MSV 3611 serves as an example. 相似文献
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基于前期对华癸中慢生根瘤菌(Mesorhizobium huakuii)7653RsRNA(small non-coding RNA,sRNA)的生物信息学预测,经Northern blot验证获得SraGsRNA。本研究采用RACE与转录组高通量深度测序确定了SraG全长,并分别利用RNAfold软件和TargetRNA软件预测了SraG二级结构和靶位点,进而构建了M.huakuii 7653R的SraG插入失活突变体(M.huakuii SraGmut),并对突变体接种紫云英的共生表型进行了检测。盆栽试验结果表明,与野生型菌株M.huakuii 7653R相比,接种突变株M.huakuii SraGmut的固氮能力显著下降,突变株固氮酶活性下降约40%,植株鲜质量和根瘤数目也显著降低。结果表明,SraG的功能与M.huakuii 7653R的共生固氮过程相关,作为sRNA可能参与根瘤菌的共生固氮调控过程。 相似文献
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Biological control (biocontrol) is a safe, sustainable approach that takes advantage of natural enemies such as predators, parasitic insects or pathogens to manage pests in agroecosystems. Parasitoid wasps, a very large evolutionary group of hymenopteran insects, are well-known biological control agents for arthropod pests in agricultural and forest ecosystems. Here, we summarize the recent progress on the application of parasitoid wasps in biocontrol in China for the last five years. These include species diversity of parasitoid wasps, identification of dominant parasitoid wasps associated with insect pests and biocontrol practices (three types of biological control, i.e., classical, augmentative and conservation biological control) in several Chinese agroecosystems. We then treat different mass-rearing and release technologies and the commercialization of several parasitoid wasp species. We also summarize other work that may have a potential use in biocontrol, including the effect of plant volatiles on parasitoids and recent advance in the molecular mechanisms underlying the host regulation by parasitoid wasps. Future research area and applied perspectives are also discussed, noting that advances in biocontrol technologies in Chinese agriculture informs research at the global level. 相似文献
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A dimeric hemoglobin was purified from nitrogen-fixing root nodules formed by association of Rhizobium with a nonleguminous plant, Parasponia. The oxygen dissociation rate constant is probably sufficiently high to allow Parasponia hemoglobin to function in a fashion similar to that of leghemoglobin, by oxygen buffering and transport during symbiotic nitrogen fixation. The identification of hemoglobin in a nonlegume raises important questions about the evolution of plant hemoglobin genes. 相似文献
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Major pol gene progenitors in the evolution of oncoviruses 总被引：24，自引：0，他引：24
I M Chiu R Callahan S R Tronick J Schlom S A Aaronson 《Science (New York, N.Y.)》1984,223(4634):364-370
The genetic relationships among molecularly cloned prototype viruses representing all of the major oncovirus genera were investigated by molecular hybridization and nucleotide sequence analysis. One of the major progenitors of the pol genes of such viruses gives rise to mammalian type C viruses and another gives rise to type A, B, D, and avian type C oncoviruses. Evidence of unusual patterns of homology among the env genes of mammalian type C and D oncoviruses illustrates that genetic interactions between their progenitors contributed to the evolution of oncoviruses. 相似文献
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从GenBank上下载所有1978—2009年在中国分离的H1N1亚型流感病毒的HA和NA基因及所有同期在中国分离的A型流感病毒(宿主包括人、猪和禽)的PB1、PB2、PA、NS、NP和M基因的序列,将这些基因序列与2009年在中国发生的墨西哥H1N1流感病毒的对应基因序列进行BMCMC法分析,绘制BMCMC进化树,结果揭示中国发生的墨西哥H1N1流感病毒的HA和NA基因相对独立于中国季节性H1N1流感病毒;M基因相对独立于中国国内的季节性流感病毒和禽源流感病毒;PB1基因包含在季节性流感病毒的分群内;PB2基因和NS基因与国内重排的流感病毒相关,但相对独立于国内的季节性流感病毒和禽源流感病毒;PA基因包含在国内禽流感病毒的分群内;NP基因则与国内传统的猪流感病毒相关,但相对独立于国内的季节性流感病毒和禽源流感病毒. 相似文献
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测定了7株不同来源不同毒力新城疫病毒的V基因,并对它们的差异性和遗传进化关系进行了比对分析.结果显示:7株病毒V基因之间的核苷酸同源性为81.7%-99.7%,推导氨基酸残基的同源性为75.8%-99.6%;遗传进化分析显示,7株病毒分别处在3个不同的进化分支上,毒力相似的毒株聚类在同一进化分支上,而这与基于F基因的基因分型一致.由结果可推测,新城疫病毒V基因可能与F基因具有相似的遗传变异率,V基因也适合作为病毒基因分型分析的候选靶基因. 相似文献