Complete nucleotide sequences of all three poliovirus serotype genomes. Implication for genetic relationship, gene function and antigenic determinants

The complete nucleotide sequences of the genomes of the type 2 ( P712 , Ch, 2ab ) and type 3 (Leon 12a1b ) poliovirus vaccine strains were determined. Comparison of the sequences with the previously established genome sequence of type 1 (LS-c, 2ab ) poliovirus vaccine strain revealed that 71% of the nucleotides in the genome RNAs were common, that the 5' and 3' termini of the genomes were highly homologous, and that more than 80% of the nucleotide differences in the coding region occurred in the third letter position of in-phase codons, resulting in a low frequency of amino acid difference. These results strongly suggested that the serotypes of poliovirus derived from a common prototype. A comparison of the amino acid sequences predicted from the genome sequences showed highest variation in the capsid protein region, whereas non-structural proteins are highly conserved. Initiation of polyprotein synthesis occurs in all three strains more than 740 nucleotides downstream from the 5' end. An analysis of the non-coding region suggests that small peptides that could potentially originate from this region are conserved. The amino acid sequences immediately surrounding the cleavage signals, however, show a higher than average degree of variation. The analysis of the amino acid sequences of the capsid protein VP1 of all serotypes has led to the prediction of potential antigenic sites on the virion involved in neutralization.     

猪垂体总mRNA的提取、鉴定及其cDNA的合成

 用改进的LiCl沉淀法和寡聚(dT)-纤维素亲和层析法由猪垂体制得总mRNA。在兔网织红细胞无细胞翻译体系中进行体外翻译的结果表明,制得的总mRNA具有一定的翻译活力。翻译产物与兔抗猪生长激素抗血清发生免疫沉淀,沉淀物占总翻译产物的10％左右。SDS聚丙烯酰胺凝胶电泳的结果表明翻译产物有一条很深的带,分子量约为24,000道尔顿,与猪前生长激素的分子量相近。以制备的mRNA为模板反转录合成了双链cDNA。第一链的合成产率为10—35％,第二链的合成产率为84—115％。cDNA的平均分子长度为825bp。     

Abscisic acid induction of cloned cotton late embryogenesis-abundant (Lea) mRNAs

Summary Earlier studies found that cotton (Gossypium hirsutum L.) cotyledons contain several mRNAs which are more abundant during late embryogenesis than in mid-embryogenesis or early germination. They are here termed Late embryogenesis-abundant mRNAs, encoded by Lea loci. Complementary DNA clones for 18 such mRNA sequences, defined at a hybridization criterion of T_m-15°C, were identified in a mature embryo cDNA library by differential cDNA hybridization. At a lower hybridization criterion, some sequence homology was found within several of these cloned Lea mRNA sequences. Each Lea mRNA sequence comprises 0.04–1.3% of mature embryo poly(A)⁺ mRNA, a level ten-fold to several hundred-fold higher than in young embryo or 24 h seedling poly(A)⁺ mRNA. Of 18 Lea mRNA sequences examined in cultured young embryos, the level of at least 13 are specifically increased by exogenous abscisic acid (ABA), several to a level near that in normal mature embryos. However, the abundance of several of the sequences does not appear to be significantly modulated by ABA. The LEA polypeptides encoded by 10 Lea mRNA sequences were identified by hybrid-arrested translation. They include most of the late embryogenesis-abundant, ABA-inducible, polypeptides previously identified. Preliminary results suggest that many of the individual Lea mRNA sequences are transcribed from 1–3 genes in each of cotton's two subgenomes.     

Comparison of the Ames assay and the induction of sister chromatid exchanges: Results with ten pharmaceuticals and five selected agents

Seven antischistosomal drugs, two antimalarial drugs, and one antiamoebic drug were tested in all five Ames strains for induction of mutation, as well as for induction of cytotoxicity, inhibition of cellular progression, and the induction of sister chromatid exchanges in two cultured mammalian cell lines. We found that two agents shown to be negative in the Ames test were positive for sister chromatid exchange induction. Based on qualitative and quantitative evaluation, we find that all but three of the pharmaceuticals should be considered to be potential human carcinogens.Abbreviations AA 2-aminoanthracene - 9AACC 9-aminoacridine - AM amoscanate - BrdUU bromodeoxyuridine - CA chloroquine diphosphate - CHO Chinese hamster ovary - CQ chloroquine - DAPI 46-diamidino-2-phenylindole - DHY dehydroemetine - DMSO dimethyl sulfoxide - EB ethidium bromide - FCS fetal calf serum - FN 4-fluoro-3-nitrophenyl azide - HY hycanthone - ICP inhibiting cell progression - LU lucanthone - MEM minimal essential medium - 2NF 2-nitrofurantoin - 4NPD 4-nitro-O-phenylenediamine - NZ niridazole - OL oltipraz - OX oxaminiquine - PBS phosphate buffered saline - PQ primaquine - PZ praziquantel - SA sodium azide - SCE sister chromatid exchange     

Isolation and characterization of a human interleukin 2 gene

An interleukin 2 (IL-2) gene was isolated from a Charon 4A human gene library. Electron microscopic examination of 15 heteroduplexes formed between the genomic DNAs and the IL-2 cDNAs demonstrated that the size of the IL-2 gene is about 5.1 +/- 0.5 kb and that there are at least two introns in this gene. Nucleotide sequence of the 5' flanking region of the IL-2 gene showed a homology with that of the corresponding region of the human immune interferon gene.     

脊髓灰质炎病毒中Ⅰ9株基因组克隆及其部分结构分析

以脊髓灰质炎病毒RNA为模板,反转录合成了长链ds-cDNA。将合成的脊灰病毒中I9株ds—cDNA片段重组到质粒pAT153上,获得了约占脊灰病毒中I9基因组95％以上的cDNA克隆。对克隆的中I9cDNA部分片段作了限制性内切酶图谱分析和部分核酸的序列分析,发现脊灰病毒中I9部分核酸顺序有所改变。     

单克隆抗体γ3重链可变区cDNA的合成与克隆

用异硫氰酸胍法从分泌单克隆抗体的杂交瘤细胞中提取总RNA,经oligo(dT)-纤维素柱亲和层析获得poly(A)~ RNA后,用恒定区5′端第122—125号氨基酸密码的互补序列3′A-T-A-G-G-T-G-A-C-C 5′做为引物,进行逆转录酶反应,合成双链cDNA,大小为300bp左右,与重链可变区基因的长度相符。用dC:dG接尾的方法,将ds-cDNA插入pUC19质粒,转化E.coli HB101。分离出重组体之后,经菌落原位杂交,酶切重组质粒DNA及Southern印迹,证明插入片段是重链可变区基因。     

大麦条纹花叶病毒新疆株(BSMV-XJ)RNA_2的cDNA克隆及5′端序列分析

分离了大麦条纹花叶病毒(BSMV)新疆株基因组的3个RNA组份。以RNA2为模板,3′端互补寡核苷酸为引物,合成了第一条cDNA链和第二条cDNA链,将ds-cDNA重组在pUC9质粒中,转化大肠杆菌细胞,获得含RNA3′端的克隆,并证明所选克隆的cDNA含有新疆株几近全长的RNA2组份。对于插入片段为3.3kbp的112号克隆进行了酶谱分析,得到了与国外典型株类似的结果;用双脱氧终止法分析了相当于RNA 2 5′端250bp的cDNA酶切片段,表明与国外典型株有十分相似的一级结构。     

Artificial Feeding Systems for Plant-Parasitic Nematodes

Feeding of an "obligate" plant-parasitic nematode (nonfungal feeder), Pratylenchus scribneri, in the absence of plant tissue was demonstrated in an artificial system consisting of liquid media and indicator dyes including amaranth and various nontoxic food colors. Among the compounds tested, sucrose, dextrose, Gamborg''s B5 medium, and DL-methionine stimulated a small percentage of feeding (12-36%). A high percentage of feeding (90-100%) occurred in a filtrate from excised corn roots cultured in Gamborg''s B5 medium. This feeding system has the potential to develop an artificial medium for plant-parasitic nematodes and to screen novel nematicides that are stomach poisons.