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1.
《环境昆虫学报》2013,35(1):95-101
昆虫对苏云金杆菌(Bacillus thuringiensis, Bt)毒素产生抗性的机理很多,其中Bt毒素与中肠细胞膜上受体结合能力的变化、Bt毒蛋白在中肠中水解作用的变化是抗性产生的两个主要环节。本文综述了昆虫取食Bt毒素后其体内中肠蛋白酶、解毒酶及保护酶活性的变化及这些变化与抗性之间的关系。结果表明,室内及田间对Bt毒素产生抗性的昆虫品系,可能与这三大酶系存在一定的关系。研究分析昆虫对Bt毒素的抗性机理,将有助于建立早期的抗性监测技术、实施抗性治理方案,实现Bt农药与转Bt基因作物的可持续利用。  相似文献   

2.
苏云金杆菌(Bacillus thuringiensis,Bt)Bt33菌株是从736株野生型Bt菌中筛选分离的1株对烟草粉螟具有高效杀虫活性的菌株,鉴定为科尔默亚种。本研究对Bt33菌株进行了初始接种量、培养基及发酵条件优化,晶体蛋白质电镜观察和SDS-PAGE分析,在室内及烟叶仓库中进行了防治效果测定,对施用Bt33后的烟叶进行了化学成分分析及单体烟评吸。结果表明,应用Bt33防治烟草粉螟效果好;对烟叶的化学成分影响不大;单体烟评吸分显著高于对照,用Bt33防治烟叶仓库害虫烟草粉螟有一定的发展潜力。  相似文献   

3.
种植转Bt基因棉土壤中Bt蛋白的分布   总被引:2,自引:0,他引:2  
采用盆栽试验结合酶联免疫法(ELISA)测定了转Bt基因抗虫棉及常规棉花不同生育期根际及非根际土壤中的Bt蛋白含量.结果表明:红壤、黄棕壤及黄褐土种植转Bt基因棉花后根际土中Bt蛋白含量显著高于非根际土,而种植常规棉花的根际土与非根际土中Bt蛋白含量差异不显著.在初蕾期转Bt基因棉根际土中的Bt蛋白含量为黄褐土>黄棕壤>红壤,分别为常规棉根际土的144%、121%和238%;而在盛花期为黄棕壤>黄褐土>红壤,分别为常规棉根际土的156%、116%和197%.无论种植转Bt基因棉还是常规棉,供试土壤的根际和非根际土中Bt蛋白含量都随棉花生育期的推进先增加后减少,在盛花期达最大值.整个生育期内,转Bt基因棉根际土中的Bt蛋白含量大于其非根际土;种植转Bt基因棉土壤中Bt蛋白含量高于常规棉,说明转Bt基因棉花的Bt蛋白可释放到根际土中.  相似文献   

4.
Bt杀虫晶体蛋白基因及其转基因育种研究进展   总被引:9,自引:0,他引:9  
本文简要介绍了Bt杀虫晶体蛋白及其编码基因,以及目前通过基因工程方法获得的转Bt杀虫晶体蛋白基因植物,着重分析和探讨了目前转Bt杀虫晶体蛋白基因植物及转基因育种研究中存在的一些问题,并就这些问题及合理持续利用Bt杀虫晶体蛋白提出了一些见解。  相似文献   

5.
廖文宇  吕卓鸿  张友军  杨中侠 《昆虫学报》2022,65(11):1547-1564
作为最成功的生物农药,苏云金芽孢杆菌Bacillus thuringiensis (Bt)杀虫剂已在农业生产中应用了约80年。Bt由于其特异性强、安全高效的特点而得到广泛、成功的应用,极大减少了化学农药的用量,为环境保护作出了巨大贡献。然而,由于长期使用,一些靶标害虫逐渐对Bt产生抗性。本文对昆虫体液免疫及昆虫Bt抗性机制的研究成果进行了总结,已有研究认为害虫对Bt产生抗性的主要原因是毒素激活受阻及(或)毒素受体突变或减少。然而近年越来越多的研究表明,昆虫的Bt抗性还与其免疫系统,特别是与Toll, IMD和proPO-AS等体液免疫通路有关。由此,本文对昆虫体液免疫系统参与昆虫Bt抗性形成的主要通路进行了归纳和推论。IMD免疫通路可能通过MAPK信号通路参与调节昆虫Bt抗性,或可能通过多种免疫反应对抗因中肠组织被Bt破坏而引起的败血症,并通过JNK信号通路促使中肠组织愈合,进而提高其对Bt的抗性。从体液免疫系统切入研究,可能成为深入探索昆虫Bt抗性机制的新方向。  相似文献   

6.
转Bt基因抗虫水稻的研究进展与生态安全评价   总被引:17,自引:3,他引:14  
表达杀虫蛋白的转Bt基因植物正在改革着现代农业.综述了国内外转Bt基因水稻及其抗虫性的研究进展及水稻害虫对Bt水稻的抗性风险及抗性管理策略,提出了对转基因Bt水稻进行生态安全风险评价的具体内容.  相似文献   

7.
影响苏云金芽孢杆菌基因在转基因植物中表达的因素   总被引:3,自引:0,他引:3  
苏云金芽孢杆菌(Bacillus thuringiensis,Bt)杀虫晶体蛋白基因是植物抗虫基因工程中应用最广泛的基因资源。影响Bt基因在转基因植物中表达的因素繁多,阐明这些因素的效应对于获得Bt基因在受体植物中的稳定高效表达具有重要意义。现对Bt基因表达的主要影响因子,如Bt基因表达单元、植物发育、外部环境条件、受体植物遗传背景、整合位点及Bt基因沉默现象等进行了综述。  相似文献   

8.
随着Bt作物种植面积的逐年增加, 人们对Bt作物释放后潜在的安全性也越来越关注。Bt作物释放的Bt蛋白可以主要通过秸秆还田方式进入土壤进而可能会对土壤生态系统造成影响。本文综述了Bt作物秸秆还田释放的Bt蛋白在土壤中的降解及对土壤生态系统影响的研究进展。重点阐述了①Bt作物秸秆还田释放的Bt蛋白在土壤中的降解; ②Bt作物秸秆还田对土壤微生物的影响; ③Bt作物秸秆还田对土壤动物的影响; ④Bt作物秸秆还田对土壤酶活性的影响; ⑤Bt作物秸秆还田对土壤养分含量的影响。从而为Bt作物秸秆还田对土壤环境的生态风险评价提供参考。  相似文献   

9.
迄今为止,全球已有2个Bt株菌株完成了全基因组测序,1个Bt菌株正在拼接中,15个Bt菌株正在进行测序中.已有22个Bt质粒完成了全序列测定.Bt是作为生物农药使用最广泛的微生物菌株,也是最为成功地将其杀虫晶体蛋白基因应用于植物转基因的微生物.在基因组进化、新基因发现、基因表达调控等方面一直是科学家研究的热点,并取得了相当多的成果.本文概述了苏云金芽孢杆菌基因组测序现状、基因组特征及比较基因学等方面的研究进展.  相似文献   

10.
 在盆栽种植条件下,比较研究了两个转Bt基因棉(Gossypium hirsutum)与对照棉对根际土壤细菌、放线菌、真菌和主要功能类群及多样性的影 响差异。结果表明:两个转Bt基因棉根际土壤均可检测到Bt蛋白,且不同转Bt基因棉根系分泌Bt蛋白量以及Bt蛋白在根际土壤中的降解率不同 。与各自对照相比,转Bt基因棉对细菌和真菌生长繁殖有促进作用,对放线菌、好气固氮菌和钾细菌数量没有显著影响。苗期和花期转Bt基因 棉均可显著提高氨化细菌、显著降低无机溶磷菌数量,花期均可显著提高好气纤维分解菌、显著降低有机溶磷菌数量,‘Bt冀668’苗期也可显 著提高好气纤维分解菌数量。转Bt基因棉根际土壤好气纤维分解菌、有机和无机溶磷菌多度发生了变化。尽管功能类群总数转Bt基因棉高于各 自对照常规棉,但群落多样性和均匀度都有所下降,优势集中性表现明显,且花期转Bt基因棉多样性参数值以及功能类群数量的变化幅度大于 苗期。  相似文献   

11.
The Cuban species of Calisto are reviewed based on the morphology of adult and immature stages, as well as DNA sequences of six genes (COI, EF1α, wingless, GAPDH, RpS5, CAD). A new species, Calisto occultasp. n., is described from the northeastern Cuban mountains. Calisto smintheus Bates, 1935 and Calisto bruneri, Michener 1949 are revised and revalidated. A new status, the species level, is proposed for Calisto brochei, Torre 1973, Calisto muripetens, Bates 1939 and Calisto bradleyi, Munroe 1950. The immature stages of Calisto smintheus, Calisto brochei,and Calisto occulta are described for the first time, and those of Calisto herophile, Hübner 1823 are redescribed. Useful morphological characters for adults are the shape and conspicuousness of androconial patch, the number and relative size of white dots on underside of hindwing, the shape of aedeagus, the shape of digitiform projection of genitalia valve, the shape and relative size of tegumen and uncus, the relative size of female genitalia, the height of sterigmal ring dorsal crown of the latter, and the relative size of corpus bursae and ductus bursae. For the immature stages, the most important characters are the color pattern of head capsule, the number and width of longitudinal lines of body, in the larvae; and the color pattern and the absence or presence of dorsal ridges on the abdomen of pupae. The phylogenetic relationships between the Cuban Calisto species are quite robust and well-supported; however, conflict between mitochondrial and nuclear datasets was detected in Calisto brochei, Calisto muripetens and to a lesser degree in Calisto bradleyi.  相似文献   

12.
B. A. Manny  D. Kenaga 《Hydrobiologia》1991,219(1):269-279
Despite extensive urbanization of its watershed, the Detroit River still supports diverse fish and wildlife populations. Conflicting uses of the river for waste disposal, water withdrawals, shipping, recreation, and fishing require innovative management. Chemicals added by man to the Detroit River have adversely affected the health and habitats of the river's plants and animals. In 1985, as part of an Upper Great Lakes Connecting Channels Study sponsored by Environment Canada and the U.S. Environmental Protection Agency, researchers exposed healthy bacteria, plankton, benthic macroinvertebrates, fish, and birds to Detroit River sediments and sediment porewater. Negative impacts included genetic mutations in bacteria; death of macroinvertebrates; accumulation of contaminants in insects, clams, fishes, and ducks; and tumor formation in fish. Field surveys showed areas of the river bottom that were otherwise suitable for habitation by a variety of plants and animals were contaminated with chlorinated hydrocarbons and heavy metals and occupied only by pollution-tolerant worms. Destruction of shoreline wetlands and disposal of sewage and toxic substances in the Detroit River have reduced habitat and conflict with basic biological processes, including the sustained production of fish and wildlife. Current regulations do not adequately control pollution loadings. However, remedial actions are being formulated by the U.S. and Canada to restore degraded benthic habitats and eliminate discharges of toxic contaminants into the Detroit River.Contribution 738 of the National Fisheries Research Center-Great Lakes, 1451 Green Road, Ann Arbor, MI 48105, U.S.A.  相似文献   

13.
Nine of 10 genera and 119 of approximately 240 species of the Pinaceae occur in China, including 67 endemic species and two endemic genera. In this paper, the distributional maps of all the genera of the Pinaceae are presented (fig. 1-8). The horizontal and vertical distributions of species in each genus are discussed. The analysis of the distribution patterns of the genera indicates that some genera, such as Keteleeria, Tsuga, Pseudotsuga, Cathaya and Pseudolarix, are restricted to the area south of the Qinling Mountains and the Huaihe River, and the others, i. e. Picea, Abies, Larix and Pinus, extend northward to northeastern China. However, all of the genera except Keteleeria and Pinus are not found in very dry areas and tropical mountainous regions of China. The monotypic genera, Cathaya and Pseudolarix, are distributed in eastern and central China. The genus Keteleeria consists of 10 species, 7 of which are concentrated in southern Guizhou, northern Guangxi, southwestern Hunan and easternmost Yunnan. The distribution of the remaining 6 genera shows the maximum concentration in western Sichuan and northwestern Yunnan. (Figs. 2-8). Furthermore, more than third of species of the Pinaceae (37.8%) are also concentrated in western Sichuan and northwestern Yunnan. where a great variety of habitats and different topographic features occur. It is apparent that to conduct our systematic and evolutionary studies on this family in these region is especially needed. The relations between the areal size and the tolerance of species are discussed. The distributions of macrofossils and microfossils of the genera of the Pinaceae ia China are given, and it has been proved that areas of most genera of the family were considerably larger in the past. than at present.  相似文献   

14.
The Hierarchical Taxonomy of Psychopathology (HiTOP) is a scientific effort to address shortcomings of traditional mental disorder diagnoses, which suffer from arbitrary boundaries between psychopathology and normality, frequent disorder co‐occurrence, heterogeneity within disorders, and diagnostic instability. This paper synthesizes evidence on the validity and utility of the thought disorder and detachment spectra of HiTOP. These spectra are composed of symptoms and maladaptive traits currently subsumed within schizophrenia, other psychotic disorders, and schizotypal, paranoid and schizoid personality disorders. Thought disorder ranges from normal reality testing, to maladaptive trait psychoticism, to hallucinations and delusions. Detachment ranges from introversion, to maladaptive detachment, to blunted affect and avolition. Extensive evidence supports the validity of thought disorder and detachment spectra, as each spectrum reflects common genetics, environmental risk factors, childhood antecedents, cognitive abnormalities, neural alterations, biomarkers, and treatment response. Some of these characteristics are specific to one spectrum and others are shared, suggesting the existence of an overarching psychosis superspectrum. Further research is needed to extend this model, such as clarifying whether mania and dissociation belong to thought disorder, and explicating processes that drive development of the spectra and their subdimensions. Compared to traditional diagnoses, the thought disorder and detachment spectra demonstrated substantially improved utility: greater reliability, larger explanatory and predictive power, and higher acceptability to clinicians. Validated measures are available to implement the system in practice. The more informative, reliable and valid characterization of psychosis‐related psychopathology offered by HiTOP can make diagnosis more useful for research and clinical care.  相似文献   

15.
The development of new taxonomical theories and approaches, particularly molecular phylogenetics, has led to the expansion of traditional morphology-based taxonomy into the concept of "integrative taxonomy." Taxonomic knowledge has assumed greater significance in recent years, particularly because of growing concerns over the looming biodiversity crisis. Since its establishment in 1938, the Kunming Institute of Botany (KIB), which is located in Yunnan province in Southwest China, has focused attention on the taxonomy and conservation of the flora of China. For the forthcoming 80th anniversary of KIB, we review the achievements of researchers at KIB and their associates with respect to the taxonomy of land plants, fungi, and lichen. Major taxonomic advances are summarized for families of Calymperaceae, Cryphaeaceae, Lembophyllaceae, Neckeraceae, Polytrichaceae and Pottiaceae of mosses, Pteridaceae and Polypodiaceae of ferns, Taxaceae and Cycadaceae of gymnosperms, Asteraceae, Begoniaceae, Ericaceae, Euphorbiaceae, Gesneriaceae, Lamiaceae, Orchidaceae, Orobanchaceae, Poaceae, Theaceae and Urticaceae of angiosperms, Agaricaceae, Amanitaceae, Boletaceae, Cantharellaceae, Physalacriaceae Russulaceae, Suillaceae and Tuberaceae of fungi, and Ophioparmaceae and Parmeliaceae of lichens. Regarding the future development of taxonomy at KIB, we recommend that taxonomists continue to explore the biodiversity of China, integrate new theories and technologies with traditional taxonomic approaches, and engage in creative monographic work, with support from institutions, funding agencies, and the public.  相似文献   

16.
A key is presented for use in identifying asymmetrically winged fruits (samaras) with either proximal or distal locules. It aids identification based on dispersed fuit morphology and can be used to identify undetermined extant herbarium specimens or fossil fruits to the correct extant family and genus. The 39 genera from 11 families (Aceraceae, Anacardiaceae, Fabaceae, Malpighiaceae, Phytolaccaceae, Polygalaceae, Polygonaceae, Rutaceae, Sapindaceae, Trigoniaceae, Ulmaceae) are distinguished on the basis of wing venation, size of fruit, presence and position of attachment surface, presence and type of subsidiary wings on the ovary wall. ornamentation, size and shape of the ovary, locule position, shape of locule cross section, style position and ornamentation, distinction between ovary wall and wing, and angle of attachment between individual samaras. The developmental origins of some of these features are discussed.  相似文献   

17.
Numbers of species and genera,endemic genera,extant primitive genera,relationship and distribution patterns of presently living Chenopodiaceae(two subfamilies,12 tribes,and 118 genera)are analyzed and compared for eight distributional areas,namely central Asia,Europe,the Mediterranean region,Africa,North America,South America, Australia and East Asia. The Central Asia,where the number of genera and diversity of taxa are greater than in other areas,appears to be the center of distribution of extant Chenopodiaceae.North America and Australia are two secondary centers of distribution. Eurasia has 11 tribes out of the 12,a total of 70 genera of extant chenopodiaceous plants,and it contains the most primitive genera of every tribe. Archiatriplex of Atripliceae,Hablitzia of Hablitzeae,Corispermum of Corispermeae,Camphorosma of Camphorosmaea,Kalidium of Salicornieae,Polecnemum of Polycnemeae,Alexandra of Suaedeae,and Nanophyton of Salsoleae,are all found in Eurasia,The Beteae is an Eurasian endemic tribe,demonstrating the antiquity of the Chenopodiaceae flora of Eurasia.Hence,Eurasia is likely the place of origin of chenopodiaceous plants. The presence of chenopodiaceous plants is correlated with an arid climate.During the Cretaceous Period,most places of the continent of Eurasia were occupied by the ancient precursor to the Mediterranean,the Tethys Sea.At that time the area of the Tethys Sea had a dry and warm climate.Therefore,primitive Chenopodiaceae were likely present on the beaches of this ancient land.This arid climatic condition resulted in differentiation of the tribes Chenopodieae,Atripliceae,Comphorosmeae,Salicornieae,etc.,the main primitive tribes of the subfamily Cyclolobeae. Then following continental drift and the Laurasian and Gondwanan disintegration, the Chenopodiaceae were brought to every continent to propagate and develop, and experience the vicissitudes of climates, forming the main characteristics and distribution patterns of recent continental floras. The tribes Atripliceae, Chenopodieae, Camphorosmeae, and Salicornieae of recent Chenopodiaceae in Eurasia, North America, South America, southern Africa, and Australia all became strongly differentiated. However, Australia and South America, have no genera of Spirolobeae except for a few maritime Suaeda species. The Salsoleae and Suaedeae have not arrived in Australia and South America, which indicates that the subfamily Spirolobeae developed in Eurasia after Australia separated from the ancient South America-Africa continent, and South America had left Africa. The endemic tribe of North America, the tribe Sarcobateae, has a origin different from the tribes Salsoleae and Suaedeae of the subfamily Spirolobeae. Sarcobateae flowers diverged into unisexuality and absence of bractlets. Clearly they originated in North America after North America had left the Eurasian continent. North America and southern Africa have a few species of Salsola, but none of them have become very much differentiated or developed, so they must have arrived through overland migration across ancient continental connections. India has no southern African Chenopodiaceae floristic components except for a few maritime taxa, which shows that when the Indian subcontinent left Africa in the Triassic period, the Chenopodiaceae had not yet developed in Africa. Therefore, the early Cretaceous Period about 120 million years ago, when the ancient Gondwanan and Laurasian continents disintegrated, could have been the time of origin of Chenopodiaceae plants.The Chinese flora of Chenopodiaceae is a part of Chenopodiaceae flora of central Asia. Cornulaca alaschnica was discovered from Gansu, China, showing that the Chinese Chenopodiaceae flora certainly has contact with the Mediterranean Chenopodiaceae flora. The contact of southeastern China with the Australia Chenopodiaceae flora, however, is very weak.  相似文献   

18.
Chemical basis of inflammation-induced carcinogenesis   总被引:11,自引:0,他引:11  
Chronic inflammation induced by biological, chemical, and physical factors has been associated with increased risk of human cancer at various sites. Inflammation activates a variety of inflammatory cells, which induce and activate several oxidant-generating enzymes such as NADPH oxidase, inducible nitric oxide synthase, myeloperoxidase, and eosinophil peroxidase. These enzymes produce high concentrations of diverse free radicals and oxidants including superoxide anion, nitric oxide, nitroxyl, nitrogen dioxide, hydrogen peroxide, hypochlorous acid, and hypobromous acid, which react with each other to generate other more potent reactive oxygen and nitrogen species such as peroxynitrite. These species can damage DNA, RNA, lipids, and proteins by nitration, oxidation, chlorination, and bromination reactions, leading to increased mutations and altered functions of enzymes and proteins (e.g., activation of oncogene products and/or inhibition of tumor-suppressor proteins) and thus contributing to the multistage carcinogenesis process. Appropriate treatment of inflammation should be explored further for chemoprevention of human cancers.  相似文献   

19.
Athyrisinine brachiopods from the Upper Silurian of Russia and the Lower–Middle Devonian of China and north Vietnam include over 70 species belonging to Athyrisina and Parathyrisina ; generic and subfamilial diagnoses are emended. Five genera are considered synonyms of Athyrisina and three of Parathyrisina . A neotype is selected and illustrated for Athyrisina squamosa , the type species of Athyrisina . Four nomina nova , Athyrisina xui , Parathyrisina wani , P. minima , and P. cheni , are suggested as new substitute names for Athyrisina tumida Wang, in Xu et al. 1978 (primary homonymy), Athyrisinoides ganxiensis Wan, in Xu et al. 1978, Parathyrisina minor Zhang, in Zhang and Fu 1983, and Athyrisinoides tudilingensis Chen, 1979 (secondary homonyms) respectively. A new genus, Bruntosina , is described from the Emsian to Eifelian of the Qinling region. A new subfamily, Homeathyridinae, is erected within the Athyrididae with Homeathyris , Pseudohomeospira , and Squamathyris included, revised and their diagnoses emended. Homeathyris incisus sp. nov. is described from the Ludfordian of Novaya Zemlya. Ikella is revised and excluded from the athyrisinins. The origin and dispersal of the homeathyridins and the athyrisinins are discussed.  相似文献   

20.
Summary Parasitic flowering plants from 23 genera in 7 families (Convolvulaceae, Lauraceae, Loranthaceae, Orobanchaceae, Santalaceae, Scrophulariaceae and Viscaceae) have been cultured in vitro. These plants include both hemiparasites and holoparasites that parasitize stems and roots of angiosperms and gymnosperms. This review highlights relevant information on each genus with regard to its biology, distribution, host range, and tissue culture procedures. Tissue culture has been used to study aspects of the development, metabolism, reproduction, physiology and nutritional requirements of these plants under controlled conditions. Studies of host-parasite relationships, including potential roles of signals/receptors that influence host development and physiology, and factors influencing seed germination and haustorium formation, have been conducted. The effects of chemicals and herbicides on the physiology and biochemistry of parasite embryo and seedling development have been studied, as well as the influence of inhibitors or stimulants on seed germination. Tissue culture has provided a method for propagation and genetic improvement of plants with commercial value.  相似文献   

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