两株枯草芽孢杆菌的噬菌体

从三门峡酶制剂厂分离到与过去形态不同的两种噬菌体BS3l和BS32。BS31有收缩尾鞘,头部为六边形;BS32有复杂的短尾,形态与φ29相似,寄主范围窄且有差异,用限制酶分析,噬菌体DNA的分子量分别为62kb和17kb。根据解链温度计算噬菌体DNA的G十c含量分别为45．7mol％和40．7mol％。两株噬菌体的结构蛋白经SDS聚丙烯酰胺凝胶电沫测定,BS3l有2条主带,10条次带;BS32有3条主带和6条次带。     

枯草芽孢杆菌AS1.398的温和噬菌体

中性蛋白酶生产菌 Bacillus subtilis ASI．398为双溶源菌,能产细菌素,经紫外线和丝裂霉素C诱导,分离到二林温和噬菌体BSLl 0和BSLll。电镜观察表明,二株噬菌体形态相似,均属长尾噬菌体科的成员,经EcoRl限制酶消解,将BSLl0和RSLll分别切割成6和14个片段,经电泳方法测定其分子量分别为22．6kb和51．7kb。BSLl0和BSLll DNA的G十C含量分别为65mol％和60．2mol％。两者蛋白经SDS-聚丙烯酰胺凝肢电泳检测发现分别有3和4条主带。     

小单孢菌40027菌株噬菌体的分离及其生物学特性的研究

以福堤霉素A产生菌──小单孢菌40027菌株为指示菌,从土壤中分离得到三株噬菌体:ΦHAU7、ΦHAU9和ΦHAU11。三株噬菌体的寄主专一性较强,在测试的15株放线菌菌株中,三株噬菌体能感染小单孢菌40027菌株和A-M-01菌株,ΦHAU9和ΦHAU11还能感染蔷薇小单孢菌(Micromonospora purprea)。三株噬菌体都是由多面体的头部和尾部组成;形成噬菌斑时培养基中适宜的Ca2 、Mg2 浓度分别为32mM和30mM;ΦHAU7在储存液中适宜的pH范围为6~12,而其它两株噬菌体的适宜的pH范围为6~10;在储存过程中三株噬菌体适宜的温度范围为28~37℃,经60℃保温30min后,除ΦHAU7仍有53%活力之外,其它两株噬菌体全部失活。限制性内切酶酶切结果表明:三株噬菌体基因组DNA均为双链DNA;基因组大小分别约为60kb、58kb和55kb。高压脉冲电泳结果揭示:三株噬菌体基因组DNA均具有粘性末端。     

碱性蛋白酶生产菌——地衣芽孢杆菌(B. licheniformis)的温和噬菌体

碱性蛋白酶生产菌——地衣芽孢杆菌经丝裂霉素C或紫外线处理,均可诱导释放噬菌体,电镜观察表明噬菌体头部外廓呈六边形,有不收缩的尾部(头部40nm×40nm,尾部107×5,7nm),噬菌体BLL1 DNA对限制酶Eco R Ⅰ,HindⅢ和Bam H Ⅰ敏感,分别切割成8,15,和9个片段,经电泳法测定。噬菌体DNA分子量约相当于23.4kb,根据解链温度计算出噬菌体的G+C含量约为31.2摩尔％,噬菌体提纯的外壳蛋白经SDS-聚丙烯酰胺凝胶电泳呈现5条主带,其分子量分别约为78000,72000,55000,39000,35000。     

铜绿假单胞菌噬菌体的分离鉴定及耐噬菌体突变频率测定

用铜绿假单胞菌为宿主菌自污水中分离到3株不同的铜绿假单胞菌噬菌体,命名为PaP1、PaP2及PaP3者均为DNA双链噬菌体,基因组大小分别约为47kb、34kb及24kb。3株噬菌体原液滴度（pfu）分别为109/mL、1011/mL和1011/mL。PaP1为裂菌性噬菌体,PaP2及PaP3为溶原性噬菌体。电镜观察,3株噬菌体头部均为多面体立体对称颗粒,直径分别约为70nm、55nm和65nm。PaP1属肌尾噬菌体科,PaP2和PaP3属短尾噬菌体科。研究中还发现了铜绿假单胞菌的耐噬菌体现象及耐受菌与敏感菌之间的“菌群交替”现象,经测定铜绿假单胞菌耐噬菌体的突变机率在1.4×10-7～7.9×10-7之间。     

一株苏云金杆菌噬菌体的形态结构及其蛋白质性质

从武汉微生物药厂苏云金杆菌发酵裂解液中分离到1株具有独特形态结构的苏云金杆菌噬菌体GP-1。电镜观察发现,这株噬菌体的头部呈长六棱柱状,具一短直尾和一“衣领”状结构,并首次发现了“衣领”状结构是由8～10个颗粒亚单位组成。该株噬菌体所具有的这8～10个颗粒亚单位对于噬菌体牢固地吸附于宿主表面应具有很强的促进作用,对于进一步研究噬菌体与宿主之间的关系提供一个结构上的证据。该株噬菌体的蛋白经SDS-聚丙烯酰胺凝胶电泳法测定,呈现一条主带,分子量为58892 D,一条次主带和七条次带,表明该株噬菌体的蛋白是由9种蛋白质构成。     

三株苏云金杆菌噬菌体的形态结构及其蛋白性质的比较研究

对来自武汉微生物药厂的发酵裂解液中的噬斑形态、大小不同的 3株苏云金杆菌噬体的形态结构及其蛋白性质进行了比较研究。电镜观察发现 ,所有噬菌体的头部都呈长六棱柱状 ,具一短尾和一“衣领”状结构 ,并首次发现了“衣领”状结构是由 8～ 10个颗粒亚单位组成。 3株噬菌体所具有的这 8～ 10个颗粒亚单位对于噬菌体牢固地吸附于宿主表面应具有很强的促进作用 ,对于进一步研究噬菌体与宿主之间的关系提供一个结构上的证据。3株噬菌体的蛋白经SDS 聚丙烯酰胺凝胶电泳测定 ,都呈现 1条主带 ,分子量为 5 8884u ,1条次主带和 7条次带 ,表明 3株噬菌体的蛋白都是由 9种蛋白质构成。     

8株动物源编码Stx2短尾噬菌体的生物学特性

[目的]对8株源自大肠杆菌O157编码Stx2毒素的噬菌体生物学特性进行研究.[方法]丝裂霉素C诱导8株大肠杆菌O157菌株释放噬菌体,采用PCR作初步鉴定,分离、纯化噬菌体基因组,随机引物法地高辛(DIG)标记stx2基因片段作为探针,对纯化的噬菌体采用Southernblot进行Stx2噬菌体再次鉴定,透射电子显微镜观察纯化的8株Stx2噬菌体的形态特征,通过限制性内切酶图谱分析,确定噬菌体的核酸类型和基因组大小、以及限制性内切酶酶切片段多态性,并分析噬菌体的蛋白质组成特征.[结果]Southern blot证实分离的8株噬菌体为Stx2噬菌体,电镜下观察的各株Stx2噬菌体形态一致,头部均为正六边形,尾部很短,属于短尾噬菌体科,各株噬菌体之间存在相同的蛋白结构模式,基因组为双链DNA,限制性内切酶片段长度表现出一定的多态性,噬菌体的基因组大小从48.0-65.3 kb不等.[结论]来源不同菌株的8株编码Stx2噬菌体均为短尾噬菌体,其蛋白结构模式一致,但基因组具有不同组成.     

枯草芽孢杆菌携带PBSX类缺陷性原噬菌体的普遍性调查

【目的】对来自中国典型培养物保藏中心(CCTCC)的39株枯草芽孢杆菌中的PBSX类缺陷性原噬菌体进行普遍性调查。【方法】对实验菌株进行丝裂霉素C(MMC)诱导,得到诱导后的裂解液上清。通过裂解液上清中13 kb DNA片段的存在情况,及其对PBSX敏感菌Bacillus subtilis W23的攻击作用,判断该菌株是否携带PBSX类缺陷性原噬菌体。同时利用透射电镜检测裂解液上清中噬菌体状颗粒。【结果】39株检测菌株中,24株菌裂解液上清含有13 kb DNA片段,对W23也具有较强的攻击能力,为PBSX溶源菌;1株菌裂解液上清中含有13 kb DNA片段,但不能攻击W23;5株菌裂解液上清中不含13 kb DNA片段,但依然对W23具有一定的攻击能力;另外9株裂解液上清中不含13 kb DNA片段,对W23也不具备攻击能力,其中3株菌株裂解液上清中能检测到大小不同于PBSX的噬菌体状颗粒。【结论】39株检测菌株中,携带有PBSX的菌株占61.5%的比重,具有一定普遍性;而工业菌株以及分离自神农架土壤中的野生菌株中含有不同于PBSX的多种噬菌体状颗粒。本文结果为进一步揭示PBSX对于宿主菌的作用提供了更多的理论依据。     

铜绿假单胞菌噬菌体的分离鉴定及耐噬菌体突变频率测定*

用铜绿假单胞菌为宿主菌自污水中分离到3株不同的铜绿假单胞菌噬菌体,命名为PaP1、PaP2及PaP3者均为DNA双链噬菌体,基因组大小分别约为47kb、34kb及24kb。3株噬菌体原液滴度（pfu）分别为10⁹/mL、10¹¹/mL和10¹¹/mL。PaP1为裂菌性噬菌体,PaP2及PaP3为溶原性噬菌体。电镜观察,3株噬菌体头部均为多面体立体对称颗粒,直径分别约为70nm、55nm和65nm。PaP1属肌尾噬菌体科,PaP2和PaP3属     

Bacteriophage of Haemophilus influenzae III. Morphology, DNA Homology, and Immunity Properties of HP1c1, S2, and the Defective Bacteriophage from Strain Rd

The phages HP1c1 and S2 and a defective phage of Haemophilus influenzae have been compared. The morphology of the phages and the mol wt of their DNAs are similar, although the defective phage appears to have a different tail plate region. Electron microscope observation indicates that the defective phage does not attach to the cell surface, and its DNA appears to lack cohesive ends. The homology of the DNAs of the phages has been measured by hydridization. DNA from the defective phage shows little or no homology with the other phage DNAs. HP1c1 and S2 DNAs show a high level of homology. Each of these phages can form plaques on lawns of the lysogen of the other phage but at reduced plating efficiencies, suggesting that the two phages have related but not identical immunity systems.     

Thirteen Virulent and Temperate Bacteriophages of Lactobacillus bulgaricus and Lactobacillus lactis Belong to a Single DNA Homology Group

Thirteen virulent phages and two temperate phages of two closely related bacterial species (Lactobacillus lactis and L. bulgaricus) were compared for their protein composition, their antigenic properties, their restriction endonuclease patterns, and their DNA homology. The immunoblotting studies and the DNA-DNA hybridizations showed that the phages could be differentiated into two groups. One group contained 2 temperate phages of L. bulgaricus and 11 virulent phages of L. lactis. Inside each group, at least two common proteins of identical sizes could be detected for each phage. These proteins were able to cross-react in immunoblotting experiments with an antiserum raised against one phage of the same group. Temperate phage DNAs showed partial homology with DNAs from some virulent phages. These homologies seem to be located on the region coding for the structural proteins since recombinant plasmids coding for one of the major phage proteins of one phage were able to hybridize with the DNAs from phages of the same group. These results suggest that temperate and virulent phages may be related to one another.     

Characterization of two inducible bacteriophages, alpha 1 and alpha 2, isolated from Clostridium botulinum type A 190L and their deoxyribonucleic acids

Two inducible bacteriophages, alpha 1 and alpha 2, isolated from Clostridium botulinum type A strain 190L and their deoxyribonucleic acids (DNAs) were purified and characterized. Phage alpha 1, which is unable to form plaques on any strain of C. botulinum, was produced in large quantities after treatment with mitomycin C (MC), whereas phage alpha 2, which was induced in much lower quantities than phage alpha 1, propagated in cultures of type A strain Hall. The phage DNAs were exclusively synthesized after induction with MC. Alpha 1 and alpha 2 DNAs had sedimentation coefficients of 34.0 and 30.6 S, corresponding to molecular weights of 31.9 x 10(6) and 23.5 x 10(6), respectively. The buoyant density in CsC1 was 1.682 g/cm3 for alpha 1 DNA and 1.680 g/cm3 for alpha 2 DNA. Based on thermal denaturation characteristics, the genomes of both phages were shown to be double-stranded DNAs. Agarose gel electrophoretic profiles of the phage DNAs digested with restriction endonuclease EcoRI revealed nine fragments for alpha 1 DNA and six fragments for alpha 2 DNA. The molecular weights of the phage DNAs as determined by restriction enzyme analysis were 30.55 x 10(6) for alpha 1 DNA and 25.83 x 10(6) for alpha 2 DNA. Nontoxigenic mutants obtained from strain 190L could, like the toxigenic parent strain, produce the two phages after treatment with MC. Lysogenic conversion to toxigenicity by phage alpha 2 was not observed with the nontoxigenic mutants. It seems likely that there is no relationship between either phage genome and the toxigenicity of C. botulinum type A.     

Characterization of bacteriophage nucleic acids obtained from Clostridium botulinum types C and D.

Nontoxigenic strains of Clostridium botulinum types C and D are converted to toxigenic strains by infection with specific Tox+ bacteriophages. The nucleic acids were extracted from five converting phages, c-st, c-468, c-203, c-d6f, and d-1873, and one nonconverting phage, c-n71, and treated with nucleases. The nucleic acids isolated were not digested by RNase A, but were digested by DNase I and exonuclease III, indicating that they were double-stranded DNA. On the basis of the restriction endonuclease digestion patterns on 0.8% agarose gel electrophoresis, the length of c-st, c-n71, c-468, and c-d6f phage DNAs was estimated to be about 110 kilobase pairs and that of c-203 and d-1873 was about 150 kilobase pairs. The digestion patterns of c-st, c-468, and c-n71 phage DNAs by PstI and HindIII were very similar. High homology was observed in the dot hybridization test. For other phages and nucleases, a good similarity was not observed. Only a little similarity was observed between c-203 and c-d6f phages. The existence of the structural genes for the toxin in both c-st and c-n71 phages was confirmed by the hybridization test with these phage DNAs and the oligonucleotide probe which represented the DNA sequence predicted for the N-terminal amino acids (2 to 17) of C. botulinum type C toxin. The loss of the converting ability of c-n71 phage may be caused not by the deletion of the tox+ gene but rather by the base mutation in c-st phage DNA.     

Characterization of bacteriophage nucleic acids obtained from Clostridium botulinum types C and D

Nontoxigenic strains of Clostridium botulinum types C and D are converted to toxigenic strains by infection with specific Tox+ bacteriophages. The nucleic acids were extracted from five converting phages, c-st, c-468, c-203, c-d6f, and d-1873, and one nonconverting phage, c-n71, and treated with nucleases. The nucleic acids isolated were not digested by RNase A, but were digested by DNase I and exonuclease III, indicating that they were double-stranded DNA. On the basis of the restriction endonuclease digestion patterns on 0.8% agarose gel electrophoresis, the length of c-st, c-n71, c-468, and c-d6f phage DNAs was estimated to be about 110 kilobase pairs and that of c-203 and d-1873 was about 150 kilobase pairs. The digestion patterns of c-st, c-468, and c-n71 phage DNAs by PstI and HindIII were very similar. High homology was observed in the dot hybridization test. For other phages and nucleases, a good similarity was not observed. Only a little similarity was observed between c-203 and c-d6f phages. The existence of the structural genes for the toxin in both c-st and c-n71 phages was confirmed by the hybridization test with these phage DNAs and the oligonucleotide probe which represented the DNA sequence predicted for the N-terminal amino acids (2 to 17) of C. botulinum type C toxin. The loss of the converting ability of c-n71 phage may be caused not by the deletion of the tox+ gene but rather by the base mutation in c-st phage DNA.     

Bacteriophages of methanotrophs isolated from fish.

Bacteriophages of methanotrophic bacteria were isolated from 67 fish. Only two phages isolated from two fish species specifically lysed Methylocystis sp. and Flavobacterium gasotypicum. The phages lysing these species were designated 63-F and CMF-1-F, respectively. The isolated phages differed greatly in the fine structure of the virion, plaque morphology, spectrum of lytic action, serological properties, and UV sensitivity. At the same time, they had identical one-step growth characteristics: their latent period equalled 5 h, lysis time was 3 to 4 h, and burst size was about 240 virions. The phages had guanine- and cytosine-rich double-stranded DNAs consisting of common nitrogen bases. The molecular masses of the DNAs as determined by the sums of restriction endonuclease cleavage fragments were 28 X 10(6) daltons for phage 63-F and 31 X 10(6) daltons for phage CMF-1-F.     

Bacteriophages of methanotrophs isolated from fish

Bacteriophages of methanotrophic bacteria were isolated from 67 fish. Only two phages isolated from two fish species specifically lysed Methylocystis sp. and Flavobacterium gasotypicum. The phages lysing these species were designated 63-F and CMF-1-F, respectively. The isolated phages differed greatly in the fine structure of the virion, plaque morphology, spectrum of lytic action, serological properties, and UV sensitivity. At the same time, they had identical one-step growth characteristics: their latent period equalled 5 h, lysis time was 3 to 4 h, and burst size was about 240 virions. The phages had guanine- and cytosine-rich double-stranded DNAs consisting of common nitrogen bases. The molecular masses of the DNAs as determined by the sums of restriction endonuclease cleavage fragments were 28 X 10(6) daltons for phage 63-F and 31 X 10(6) daltons for phage CMF-1-F.     

Lytic bacteriophages ofStreptococcus mutans

Three phages ofStreptococcus mutans were obtained and partially characterized. The three phages, designated M102, e10, and f1, were found to be strictly lytic, with host ranges restricted to only serotype c, e, and f strains of this species, respectively. Phage sensitivity was not correlated with the presence of plasmids, at least in host strains of serotypes c and e. Each phage produced clear plaques in a number of standard media, even in the presence of sucrose, indicating that the extracellular glucan polysaccharides (mutan) produced by the hosts from this substrate do not prevent phage adsorption and growth. The phages were similar in size and morphology, having icosahedral heads and long (283–287 nm), flexible, noncontractile tails. The genome of each phage was found to consist of linear, double-stranded DNA, 31–35 kb in length, with a base composition of 37–38% G+C. Restricting phage DNAs with four enzymes produced fragment patterns unique to each phage, but common bands between M102 and e10 and between e10 and f1 were produced byBamHI. Labeled e10 and M102 DNAs hybridized strongly with all three phage DNAs, indicating that they share some common sequences. The three phages appear to be more similar than expected and probably evolved from a common ancestor.     

Genomic relatedness of Staphylococcus aureus phages of the International Typing Set and detection of serogroup A, B, and F prophages in lysogenic strains

On the basis of HindIII-restriction digest analysis of genomic DNAs, the S. aureus bacteriophages of the International Typing Set were divided into five clusters designated as A, F, Ba, Bb, and Bc. The clusters A and F include all the phages of serogroups A and F and correspond to species 3A and 77 proposed by Ackermann and DuBow (1987). On the other hand, the phages of serogroup B were divided into three clusters designated as Ba, Bb, and Bc that differ significantly each from the other in their restriction patterns. The clusters Ba and Bb may represent two separate species, while the cluster Bc may include more than one phage species. For each of the phage serogroups A, B, and F, common HindIII-restriction fragments of phage 3A (1700 bp), of 53 (4060 bp), and of 77 (8300 bp) were used for the preparation of probes specific to the phages of serogroups A, B, and F. These probes were very effective, making it possible to detect up to three different prophages in a given lysogenic strain at the same time. Restriction enzyme maps of phages 3A, 53, and 77, each representing a different serogroup, were constructed. The restriction maps of phage 3A and that of phage 77 are linear, whereas that of phage 53 is circular and exhibits a circular permutation. DNAs of the phages of serogroups A and F have cohesive ends. On each restriction map, the sites corresponding to specific probes are indicated. The size of intact genomic DNA of all phages estimated by PFGE varies within the range of 41.5-46.2 kb.     

Structural Similarity and Genetic Homology between Lactobacillus casei Bacteriophages Isolated in Japan and in Finland

Three Lactobacillus casei bacteriophages, LC-Nu, PL-1, and ?FSW, were compared. Phage LC-Nu, which has not been previously characterized, originated from a local cheese plant in Finland. Phages PL-1 and ?FSW (isolated in Japan) represent the most thoroughly studied L.casei phages so far. All three phages had similar morphotypes, but still had different patterns of structural proteins, as analyzed by SDS-PAGE. The phages differed also in types of genome organization: LC-Nu and PL-1 had cohesive ends in their DNAs, and the DNA of ?FSW was circularly permuted. The initiation site and orientation of packaging of ?FSW DNA were identified. The homologies between the phage genomes were analyzed by Southern hybridization. About one-third of each phage gem me was highly homologous with other phages (homology over 85%), and two-thirds were slightly homologous (homology between 65% and 76%). DNAs from five industrial L. casei strains were also tested for homology with phage LC-Nu DNA. Phage LC-Nu related sequences were present in all the L. casei strains tested.