维生素B2产生菌原生质体诱变选育

Studies on preparation, regeneration and ultraviolet-mutagenesis of protoplasts of vitamin B2 producer Eremothecium aohbyii were reported. By using a complex enzyme system (0.5% snial digestase + 0.5% cellulase), a great number of protoplasts were obtained. Ultraviolet-mutagenesising positive mutation ratio is 14.29%. The HPLC analysis indicated that a lot of mutants were screened by using ultraviolet-mutagenesis mutation of protoplasts, Vitamin B2 produced by the mutant E3 increased 116.4%.     

Pyrethroid resistance in mosquitoes

Repeated blood feedings throughout their life span have made mosquitoes ideal transmitters of a wide variety of disease agents. Vector control is a very important part of the current global strategy for the control of mosquito-associated diseases and insecticide application is the most important component in this effort. Pyrethroids, which account for 25% of the world insecticide market, are currently the most widely used insecticides for the indoor control of mosquitoes and are the only chemical recommended for the treatment of mosquito nets, the main tool for preventing malaria in Africa. However, mosquito-borne diseases are now resurgent, largely because of insecticide resistance that has developed in mosquito vectors and the anti-parasite drug resistance of parasites. This paper reviews our current knowledge of the molecular mechanisms governing metabolic detoxification and the development of target site insensitivity that leads to pyrethroid resistance in mosquitoes.     

东亚钳蝎中一个中性哺乳动物神经毒素全长cDNA的克隆和分析

构建了东亚钳蝎毒腺cDNA文库,根据东亚钳蝎中性哺乳动物神经毒素BmKM4的氨基酸序列设计并合成引物,用PCR方法从文库中筛选到BmKM4全长cDNA序列.它由5′UTR、可读框和3′UTR组成.与其他东亚钳蝎哺乳动物神经毒素cDNA的相应区域相比,BmKM4cDNA的5′UTR高度保守,而其3′UTR则变异较大.AUG的旁侧序列为AAAATGAA,与绝大多数蝎毒素基因一致.在BmKM4mRNApoly(A)尾上游17nt处,有一典型的腺苷化信号(AATAAA).可读框编码84个氨基酸的毒素前体,包括N端19个氨基酸残基组成的信号肽,中间64个氨基酸残基组成的成熟毒素,以及C末端的额外碱性氨基酸Arg.椐据一般规律,尾端Arg在毒素前体的成熟过程中会被切除。 Abstract:A full-length cDNA sequence encoding the precursor of a neutral mammalian neurotoxin,BmKM4,was first isolated from a cDNA library made from thc venom gland of Chinese scorpion Buthus martensii Karsch.ABmKM4-specific primer and a primer corresponding to the partial sequence of pSPORT1 vector were used as forward primer and reverse primer,respectively,to screen the cDNA library by PCR reaction.Sequence analysis of positive clones showed that the BmKM4 cDNA is composed of three parts:5'UTR,open reading frame and 3'UTR.Compared with the corresponding regions of other scorpion mammalian neurotoxin cDNAs,the 5'UTR of BmKM4 cDNA is highly conservative versus highly variable for 3'UTR.The lateral sequence of initiation codon (AUG) is AAATGAA which is in consistent with that of most scorpion toxin genes.On the 3'-end,a putative polyadenylation signal (AATAAA) was 1Tnt upstream of Poly (A) tail.The open reading frame encodes a precursor of 84 amino acid residues,including a signal peptide of 19 residues,a mature toxin(BmKM4) of 64 residues,and a basic residue (Arg) tailwhich would be removed in the processing step.     

Responses of Caryopsis Germination, Seedling Emergence, and Development to Sand Water Content of Agropyron cristatum （L.） Gaertn. and Bromus inermis Leyss.

Responses of caryopsis germination, seedling emergence, and development of Agropyron cristatum （L.） Gaertn. （Gramineae） and Bromus inermis Leyss. （Gramineae）, two dominant perennial grasses in the Otindag Sandland of China, to different sand water content （SWC; 1%, 2%, 3%, 4%, 6%, 8%, 12%, 16%, and 20%） were studied comparatively. The results showed that the germination responses of the two grasses to SWC were similar （i.e. caryopses could not germinate when the SWC was below 3%; at SWC ranging from 3% to 12%, the higher the SWC, the higher the germination percentage; and at a SWC of 12%-20%, germination reached similarly high percentages）. At a sand burial depth of 0.5 cm, the threshold of SWC for seedling emergence was 6% forA. cristatum and 8% forB. inermis; at 12%-20% SWC, the seedling emergence of both species reached similarly high percentages. The seedling growth responses of these two species to SWC gradients were different. For A. cristatum, the biomass of seedlings increased with SWC from 6% to 12%, and decreased with SWC from 12% to 20%. For B. inermis, the biomass of seedlings always increased with SWC from 8% to 20%. The results also showed that the seedlings of both species allocated more biomass to the roots with decreases in SWC. The SWC changes from April to October in natural microhabitats of both species suggested that the SWC may play an important role in caryopsis germination, seedling emergence, and the growth characteristics of the two grasses. The responses of caryopsis germination, seedling emergence, and the growth characteristics of these two species to SWC may determine their distribution pattems in the Otindag Sandland.     

阴道毛滴虫染色体组型观察

采用火焰干燥法制备阴道毛滴虫染色体标本,按 Levan等方法,进行核型分析。阴道毛滴虫的染色体数目为n＝10,2n ＝20,染色体的组型为3m、3sm、1st和3T。 Abstract：　The chromosomes ofTrichomonas vaginaliswere prepared by flame-drying method. Data of chromosome were measured and calculated. According to Levan's method, analysis of karyotype was described. The results showed that the chromosome number ofT. vaginalisconsisted of twenty pairs(2n=20) and chromosome type was 3m, 3sm, 1st and 3T.     

Relationship of HLA-A, -Cw Polymorphisms with HIV/AIDS in Chinese Yi Ethnic Group of Sichuan Province1

The relationship of HLA-A, -Cw alleles on HIV infection and AIDS disease progression in the Chinese Yi ethnic group of Sichuan province were investigated. The genetic polymorphisms of HLA-A, -Cw alleles of 102 unrelated healthy Chinese Yi ethnic individuals, 68 HIV-1 infected and 21 HIV positive long-time survivors were typed by PCR-SSP assay. Statistic signifiance was determined by the χ^2 test with the SPSS software. No significant differences were observed between the HLA-A, -Cw alleles of the 68 HIV-1 infected and 102 non-infected Chinese Yi control individuals. Whereas the prevalence of A＊3601,Cw＊14（01-03）and Cw＊0304 was significantly higher in 21 long time survivors compared with 102 healthy controls with P values of 0.016, 0.016 and 0.000 by χ^2 or the Fisher exact test respectively. The result implies that A＊3601,Cw＊14（01-03） and Cw＊0304 may be associated with slow AIDS disease progression in the Chinese Yi ethnic group, further studies on this association may yield insight on the pathogenesis of HIV-1 infection.     

The genetic equidistance result: misreading by the molecular clock and neutral theory and reinterpretation nearly half of a century later

In 1963,Margoliash discovered the unexpected genetic equidistance result after comparing cytochrome c sequences from different species.This finding,together with the hemoglobin analyses of Zuckerkandl and Pauling in 1962,directly inspired the ad hoc molecular clock hypothesis.Unfortunately,however,many biologists have since mistakenly viewed the molecular clock as a genuine reality,which in turn inspired Kimura,King,and Jukes to propose the neutral theory of molecular evolution.Many years of studies have found numerous contradictions to the theory,and few today believe in a universal constant clock.What is being neglected,however,is that the failure of the molecular clock hypothesis has left the original equidistance result an unsolved mystery.In recent years,we fortuitously rediscovered the equidistance result,which remains unknown to nearly all researchers.Incorporating the proven virtues of existing evolutionary theories and introducing the novel concept of maximum genetic diversity,we proposed a more complete hypothesis of evolutionary genetics and reinterpreted the equidistance result and other major evolutionary phenomena.The hypothesis may rewrite molecular phylogeny and population genetics and solve major biomedical problems that challenge the existing framework of evolutionary biology.     

CLUSTERING POPULATIONS BY MIXED LINEAR MODELS

INTRODUCTIONInevolutionstudiesandplant(oranimal)breedingresearch,clusteranalysesarewidelyusedforgroupingpopulations.Therehavebeenalotofmethodsdevelopedforgroupingpopulations(SneathandSokal,1973;Eve-ritt,1993).Variousmethodsaredifferedinthewaysfordistance(…     

Preparation and evaluation of a new releasable PEGylated tumor necrosis factor-α(TNF-α) conjugate for therapeutic application

To design a releasable PEGylated TNF-α(rPEG-TNF-α ), a cathepsin B-sensitive dipeptide (Val-Cit moiety) was inserted into conventional PEG-modified TNF- (PEG-TNF- ), facilitating its clinical use for anti-tumor therapy. Comparative pharmaco- kinetic and pharmacodynamic studies showed that the half-lives of both PEGylated forms of TNF-α were ~60-fold greater than that of unmodified TNF-α . In addition, the in vitro bioactivity of rPEG-TNF-α was greater than that of PEG-TNF-α with the same degree of PEG modification. Release of TNF-α from rPEG-TNF-α in vitro was dependent on the presence of cathepsin B and was inhibited by a cathepsin B inhibitor. Despite the potent cytotoxicity of unmodified TNF-α against normal cells, its PEGylated forms at higher TNF-α concentrations showed low cytotoxic activity against these cells. In contrast, both forms of PEGylated TNF-α showed potent cytotoxic activity against the B16 and L929 cell lines, with rPEG-TNF-α being 5- and 9- fold more potent, respectively, than PEG-TNF-α . Moreover, rPEG-TNF-α was a more potent in vivo antitumor agent than PEG-TNF-α .