A novel gene——samfR involved in early stage of Streptomyces ansochromogenes differentiation

A 4.6 kb DNA fragment was cloned from the DNA library of Streptomyces ansochromogenes using a partial DNA fragment located in the downstream of promoter-P_(TH4) as probe. The experiments revealed that this DNA fragment consists of saw D gene and a 1.4 kb Pvu Ⅱ fragment which can accelerate mycelium formation of S. ansochromogerms. The nucleofide sequence of 1.4 kb DNA fragment was determined and analysed; the result indicated that the fragment contains one complete open reading frame (ORF) which encodes a protein with 213 amino acids, and this gene was desiguated as samfR. The deduced protein has 36% amino acid identities and 52% amino acid similarities in comparison with that encoded by hppR gene, which is involved in the regulation of catabolism for 3-(3-hydroxyphenyl) propionate (3HPP) in Rhodococcus globerulus. The function of samfR gene was studied using strategy of gene disruption, and the resulting samfR mutant failed to form aerial hyphae and spores, its development and differentiation stopped     

鹦鹉源I型禽副粘病毒F和HN基因序列测定与分析

Virion RNA was abstracted from purified type I Avian paramyxovirus strain YN-PA01(isolated from parrot)and used as a template. The fragment containing the fusion gene(F) and hemagglutinin-neuraminidase gene(HN) of the isolate was amplified by RT-PCR and cloned to the pMD18-T Vector. Using primer walking method the complete sequence of F-HN genes was obtained finally.And the respective amino acid sequence was deduced. Through relative software the phylogenetic trees on F gene and HN gene were constructed between strain YN-PA01 and reference strains. The results showed that strain YN-PA01 comparing with reference strains displays 98.7%-83.2% nucleotide homology and 98.1%-86.2% amino acid homology on F gene; 97.4%-79.1% nucleotide homology and 97.2%-83.2% amino acid homology on HN gene. Additional 6 amino acids are encoded by the HN gene ORF of strain YN-PA01 comparing with national reference strains.The studied strain YN-PA01 exhibits highest identities with strain JS/5[O1/Go either analyzed on F gene or HN gene.     

耐辐射奇球菌超氧化物歧化酶基因的克隆与序列分析

By using a 453 bp length gene fragment of superoxide dismutase(SOD)as a probe,which was firstly amplified from Deinococcus radiodurans genomic DNA by PCR with degenerate oligonucleotide primers corresponding to the conservative regions of known SODs,a putative SOD gene was identified from the database of D.radiodurans whole genome.Its 636 bp length open reading frame and 5′ and 3′ flanking sequence was determined.The conventional E.coli ribosomal and RNA polymerase binding sites were found upstream from SOD encoding region and an inverted repeat sequence downstream of the termination codon.The deduced 211 amino acid sequence of the structural gene showed a high similarity to other manganese and iron containing SODs in normally conserve regions.     

猪瘟病毒石门株NS2-3基因片段的序列测定及比较

A couple of CSFV specific primer (PF 5648 and PR 6604) was designed with the aid of computer primer designation software and synthesized based upon the relative conserved regions of published sequences of C strain. NS2-3 gene (p125 gene) fragment of CSFV Shimen strain was amplified successfully by RT-PCR from the anticoagulant blood of infected pig. The product length is 957 bp, located in the central of NS3, a putative NTPase and helicase domain. The obtained PCR product was cloned and then sequenced. The sequence showed that this fragment contained all of seven typical conserved segments of helicase superfamily, including two common NTP-binding motifs, namely, “A” site (GXGKT/S) and “B” site (3hy, 2x) D. Sequence homology analysis revealed that Shimen strain had the highest homology with Japanese strains (ALD and GPE^-), and slightly lower homology with other three CSFV strains (C, BresciaandAlfort). Shimen strain had also significant homology with two BVDV strains (NADL and SD-1). The deduced amino acid sequence homology of Shimen strain with five CSFV and two BVDV strains was all upper than 90%. It is further confirmed that this fragment is the most conserved in pestivirus amino acid sequence. It is consistent with its essential function in replication and translation of virus genome and in processing of polyprotein precursor.     

我国婴幼儿中存在不同基因型杯状病毒的感染

Human caliciviruses were detected from stool specimens collected from infants with diarrhea from Beijing and Anhui Province by using RT PCR PCR products with molecular weight around 330 were obtained by using the primer pair of 289/290,which is proved to be able to amplify both Norwalk like and Sapporo like human caliciviruses The PCR products amplified from specimens collected in Beijing(CR480) and Anhui(A141) were cloned into the T A cloning vector pUCm T and sequenced The cDNA fragment amplified from CR480 is 319bp in length,which is consistent with the molecular weight of the cDNA fragment amplified from Norwalk like viruses with the primer pair 289/290,whereas the cDNA fragment amplified from A141 is 331 bp in length,which is the size of the cDNA fragment from Sapporo like viruses The sequence analysis revealed that the cDNA from CR480(the stool specimen collected in Beijing) shared higher nucleotide and amino acid identities with selected Norwalk like viruses (from 60% to 97% and 62% to 99%,respectively)than with selected Sapporo like viruses(less than 58%),having the highest identity with Takl 1999 jp and ARG320,which belong to genotype Ⅱ of Norwalk like viruses The sequence of the cDNA from A141 (collected form Anhui Province) shared higher nucleotide and amino acid identities with selected Sapporo like viruses(from 68% to 92% and 75% to 96%,respectively) than with selected Norwalk like viruses(less than 52%) It suggests that both Norwalk like and Sapporo like human caliciviruses are circulating in China and cause diarrhea in infants and young childeren     

Identification of a Differentially Expressed Gene PPP1CB between Porcine Longissimus dorsi of Meishan and Large White×Meishan Hybrids

To study the molecular basis of heterosis,suppression subtractive hybridization was used toinvestigate the differences in gene expression between porcine Longissimus dorsi of F1 hybrids LargeWhite×Meishan and their female parents Meishan.From two specific subtractive cDNA libraries,the clonesselected by reverse Northern high-density blot screening were chosen to clone full-length cDNA by rapidamplification of cDNA ends.An expression-upregulated gene for Meishan skeletal muscle,designated proteinphosphatase 1,catalytic subunit,beta isoform(PPPICB),was identified.Porcine PPPICB contains an openreading frame encoding 327 amino acid residues with 13 and 1763 nucleotides in the 5′ and 3′ untranslatedregions,respectively.A DNA fragment of 721 nucleotides was amplified and a mutation that creates/disruptsa restriction site for endonuclease RsaI was found.The derived amino acid sequence of PPPICB has highhomology with the PPPICB of three species,Mus musculus(99%),human(99%)and mouse(100%).Thetissue expression analysis indicated that the swine PPP1CB gene is generally expressed in most tissues.Thepossible role of PPP1CB and its relation to porcine heterosis are discussed.     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.