Effects of two TMV strains on the synthesis and stability of chloroplast ribosomal RNA in tobacco leaves

Summary Multiplication of TMV-strains vulgare (light-green/dark-green mosaic symptoms) and flavum (severe yellow/green mosaic) had different effects on the ribosomal RNA of tobacco leaf chloroplasts. Vulgare inhibited chloroplast ribosomal RNA synthesis while having no effect on cytoplasmic ribosomal RNA synthesis (Fig. 2). Flavum inhibited chloroplast ribosomal RNA synthesis more severely than vulgare, and caused an earlier degradation of chloroplast ribosomal RNA than in control or vulgare-infected leaves (Fig. 1). Flavum also inhibited cytoplasmic ribosomal RNA synthesis. A connection between these differing effects on chloroplast ribosomal RNA metabolism and severity of visible symptoms is suggested, and discussed in relation to a possible influence on symptoms of denatured virus coat protein.Abbreviations TMV Tobacco Mosaic Virus - RNA Ribonucleic acid - DNA Deoxyribonucleic acid - m millions (in molecular weight values)     

E. coli ribosomal proteins are cross reactive with antibody prepared against Chlamydomonas reinhardi chloroplast ribosomal subunit

Summary Antisera prepared against purified Chlamydomonas reinhardi small chloroplast ribosomal subunit, judged homogenous by sucrose gradient velocity sedimentation and RNA gel electrophoresis was immunologically cross reactive with E. coli ribosomal proteins. The results of three different experimental approaches, namely Ouchterlony double diffusion, sucrose gradient velocity sedimentation and two dimensional crossed immunoelectrophoresis indicate that both E. coli ribosomal subunits and the chloroplast large ribosomal subunit contain proteins which show antigenic similarity to the chloroplast small ribosomal subunit proteins. However, cytoplasmic ribosomal subunits did not contain proteins which were cross reactive with immune antisera.     

DNA synthesis in UV-irradiated Escherichia coli K-12 strains carrying dnaA mutations.

Summary In this article we describe some in vivo properties of a coldsensitive ribosomal mutant from Escherichia coli. The mutation affects the rplV gene which is the structural gene of ribosomal protein L22.Our work shows that at 22°C, the biosynthesis of both ribosomal subunits and the maturation processing of 16S and 23S ribosomal RNA are impaired. Integration of our results in a general model of in vivo ribosomal assembly in E. coli is presented.     

Comparison of ribosomal proteins of chloroplast from spinach and of E. coli

Summary A comparison of ribosomal proteins from Escherichia coli and from chloroplasts of Spinach was made using two separate methods: electrophoretic migration and immunochemical cross-reaction between blotted E. coli ribosomal proteins and chloroplast ribosomal subunits antisera. It is shown that L2 from E. coli (E-12) and L4 from chloroplasts (CS-L4) comigrated and that E-L4 immunologically cross-reacted with the isolated CS-L4 antibody. Co-migration was observed for three additional couples of 50S ribosomal proteins. It is also shown that at least one 30S E. coli ribosomal protein immuno-cross reacted with a 30S chloroplast antiserum and that three couples of 30S ribosomal proteins comigrated.     

Homology between the ribosomal DNA of Escherichia coli and mitochondrial DNA preparations of maize is principally to sequences other than mitochondrial rRNA genes

E. coli ribosomal DNA has been used to probe maize mitochondrial DNA. It hybridizes primarily with chloroplast ribosomal DNA sequences and with fungal and bacterial sequences which may contaminate the mtDNA preparations. It also hybridizes to the chloroplast 16S ribosomal RNA gene sequence present in the mitochondrial genome (1) as well as to the mitochondrial 18S ribosomal RNA gene sequence. Weak sequence homology was detected between E. coli rDNA and the mitochondrial 26S ribosomal RNA gene.     

Characterization of cloned rat ribosomal DNA fragments

Summary Two Charon 4A lambda bacteriophage clones were characterized which contain all and part of the 18S ribosomal DNA of the rat. One clone contained two Eco RI fragments which include the whole 18S ribosomal RNA region and part of 28S ribosomal RNA region. The other clone contained an Eco RI fragment which covers part of 18S ribosomal RNA region. There were differences between the two clones in the non-transcribed spacer regions suggesting that there is heterogeneity in the non-transcribed spacer regions of rat ribosomal genes. The restriction map of the cloned mouse ribosomal DNA. Eco RI, Hind III, Pst I, and Bam HI sites in 18S ribosomal RNA region were in the same places in mouse and rat DNA but the restriction sites in the 5-spacer regions were different.     

Isolation of the ribosomal protein gene S6 from Schizosaccharomyces pombe

Summary We screened a Schizosaccharomyces pombe genomic library using the ribosomal protein gene SI0 from Saccharomyces cerevisiae as a probe. Hybrid-selected translation of the positive clones revealed a ribosomal protein of S. pombe which is probably equivalent to the ribosomal protein SI0 from S. cerevisiae.     

Homology between Drosophila melanogaster and Escherichia coli ribosomal proteins

Summary Antibodies raised against D. melanogaster ribosomal proteins were used to examine possible structural relationships between eukaryotic and prokaryotic ribosomal proteins. The antisera were raised against either groups of ribosomal proteins or purified individual ribosomal proteins from D. melanogaster. The specificity of each antiserum was confirmed and the identity of the homologous E. coli ribosomal protein was determined by immunochemical methods. Immuno-overlay assays indicated that the antiserum against the D. melanogaster small subunit protein S14 (anti-S14) was highly specific for protein S14. In addition, anti-S14 showed a cross-reaction with total E. coli ribosomal proteins in Ouchterlony double immunodiffusion assays and with only E. coli protein S6 in immuno-overlay assays. From these and other experiments with adsorption of anti-S14 with individual purified proteins, the E. coli protein homologous to the D. melanogaster protein S14 was established as protein S6.     

Comparison of the nuclear ribosomal units of five Chlamydomonas species

The organization of the nuclear ribosomal units of five different species of Chlamydomonas has been examined by hybridization of their nuclear DNA fragments produced by several restriction endonucleases with a radioactively labelled probe consisting of the two cloned BamHI ribosomal fragments of C. reinhardii. The results indicate that a) the ribosomal units of these five species are structurally related, b) changes in the non transcribed spacer occur in C. eugametos and in C. globosa, c) the rDNA unit of C. intermedia contains either an enlarged internal transcribed spacer or a ribosomal intervening sequence, d) the rDNA units of C. reinhardii and C. callosa are indistinguishable.     

利用基因组学和MALDI-TOF MS技术鉴定放线菌纲细菌的核糖体蛋白质标志物

【目的】基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)法基于微生物的特征蛋白指纹图谱鉴定菌种,本研究利用基因组学和MALDI-TOFMS技术鉴定放线菌纲细菌的核糖体蛋白质标志物。【方法】从MALDI-TOF MS图谱数据库选取放线菌纲代表菌种,在基因组数据库检索目标菌种,获取目标菌株或其参比菌株的核糖体蛋白质序列,计算获得分子质量理论值,用于注释目标菌株MALDI-TOFMS指纹图谱中的核糖体蛋白质信号。【结果】从8目,24科,53属,114种,142株放线菌的MALDI-TOFMS图谱中总共注释出31种核糖体蛋白质。各菌株的指纹图谱中核糖体蛋白质信号数量差异显著。各种核糖体蛋白质信号的注释次数差异显著。总共15种核糖体蛋白质在超过半数图谱中得到注释,注释次数最高的是核糖体大亚基蛋白质L36。【结论】本研究找到了放线菌纲细菌MALDI-TOF MS图谱中常见的15种核糖体蛋白质信号,可为通过识别核糖体蛋白质的质谱特征峰鉴定放线菌的方法建立提供依据。     

Proteolytic degradation of ribosomal proteins during isolation of ribosomes and ribosomal subunits from Tetrahymena

A preparation procedure previously used to isolate active ribosomal subunits from an amicronucleate strain of Tetrahymena of undefined phenoset (T. «pyriformis CGL) yields inactive subunits when applied to other amicronucleate or to micronucleate strains of this protozoa.Proteolytic degradation of a small number of ribosomal proteins during preparation of ribosomal subunits from these strains explains this results. If cell extraction and ribosome isolation are carried out in the presence of iodoacetamide, proteolytic activity is inhibited and active ribosomal subunits are obtained. Comparison of the protein complements of active ribosomal subunits prepared in the presence of iodoacetamide from three amicronucleate strains of Tetrahymena reveals small but significant differences.     

Purification and characterization of 30S ribosomal proteins from Bacillus subtilis: correlation to Escherichia coli 30S proteins

Summary Twenty proteins were isolated from the 30S ribosomal subunits of Bacillus subtilis and their amino acid compositions and amino-terminal amino acid sequences were determined. These results were compared with the data of Escherichia coli 30S ribosomal proteins and the structural correspondence of individual ribosomal proteins has been established between B. subtilis and E. coli.Post-translational modifications of amino-terminal amino acids of the ribosomal proteins which have been found in E. coli are almost absent in B. subtilis with the exception of acetylated forms of S9.     

A missense mutation in the gene coding for ribosomal protein S17 (rpsQ) leading to ribosomal assembly defectivity in Escherichia coli.

Summary The conditionally lethal mutation, 286lmis, has been mapped inside the ribosomal protein gene cluster at 72 minutes on the Escherichia coli chromosome and was found to cotransduce at 97% with rpsE (S5). The 2861mis mutation leads to thermosensitivity and impaired assembly in vivo of 30S ribosomal particles at 42°C. The strain carrying the mutation has an altered S17 ribosomal protein; the mutational alteration involves a replacement of serine by phenylalanine in protein S17. Spontaneous reversion to temperature independence can restore the normal assembly in vivo of 30S ribosomal subunits at 42°C and the normal chromatographical sehaviour of the S17 ribosomal protein in vitro. We conclude therefore that the 2861mis mutation affects the structural gene for protein S17 (rpsQ).     

Effective Immunity to Dental Caries: Protection of Gnotobiotic Rats by Local,Immunization with a Ribosomal Preparation from Streptococcus mutans

A ribosomal preparation from Streptococcus mutans 6715 was characterized for its ability to induce an immune response in gnotobiotic rats which was protective against S. mutans-induced dental caries. Animals injected in the salivary gland region with the S. mutans ribosomal vaccine developed significantly higher (P < 0.01) salivary IgA and serum IgG antibody activities against whole S. mutans cells and ribosomal preparations than nonimmunized rats. Vaccinated animals had significantly lower (67%; P < 0.01) levels of S. mutans adherent to their molar surfaces than the control rats after infection with the homologous, cariogenic S. mutans. The immunized animals had significantly fewer (P < 0.01) carious lesions on their buccal, sulcal, and proximal molar surfaces than the nonimmunized rats following challenge with the virulent organism. Animals injected with the ribosomal preparation developed salivary IgA and serum IgG antibodies with specificities to various cell surface-associated antigens such as lipoteichoic acid and glucosyltransferase, suggesting that the observed protection may be due to antibodies against cell surface contaminants of the ribosomal vaccine. These results are the first demonstration that a ribosomal preparation from S. mutans protected rats from caries formation after challenge with the homologous, virulent S. mutans.     

Phylogenetic analysis of the rplA genes encoding ribosomal protein L1

Previously we have identified therplA gene encoding ribosomal protein L1 inStreptomyces aureofaciens. Sequence comparison of ribosomal protein L1 among several bacterial genera revealed a high level of conservation. Based on this conservation, these proteins were used as a phylogenetic tool to compare evolutionary relationships among eubacteria and archaebacteria. This phylogenetic analysis of L1 ribosomal proteins including theS. aureofaciens rplA gene product revealed, except similar bacterial groupings, some new evolutionary relationships.     

AN INTERGENERIC HYBRID IN THE SAXIFRAGACEAE: EVIDENCE FROM RIBOSOMAL RNA GENES

The tandemly repeated multigene families encoding the 5S and 18S-25S ribosomal RNAs were studied at the restriction enzyme level in Tolmiea menziesii, Tellima grandiflora, and in a putative intergeneric hybrid. Using restriction endonucleases that cut once per repeat, the repeat lengths of the 5S and 18S-25S ribosomal genes were estimated. The 5S ribosomal gene repeat length is approximately 480 and 450 base pairs, respectively, in Tolmiea and Tellima. The repeat length of the 18S-25S ribosomal genes varied from 11–13 kb in Tolmiea, and was only about 9 kb in Tellima. The putative hybrid combined the repeat lengths of both Tolmiea and Tellima for both the 5S and the 18S-25S ribosomal genes. These data substantiate the occurrence of natural hybridization between Tolmiea and Tellima. For both the 5S and 18S-25S gene experiments, the hybrid appears to contain fewer repeats corresponding to Tolmiea than to Tellima.     

Ribonuclease-sensitive ribosomal vaccines

This paper presents an analysis of the protective properties of the components in ribonuclease (RNase)-sensitive ribosomal vaccines, in particular the ribonucleic acid (RNA). The protective activities in mice of purified ribosomes derived fromPseudomonas aeruginosa and fromListeria monocytogenes were compared. Both ribosomal vaccines had to be combined with the adjuvant dimethyldioctadecylammonium bromide (DDA) in order to be protective, and both lost their activity after RNase treatment. The ribosomal vaccines as well as RNA purified from the ribosomes induced non-specific protection. Intraperitoneal injection of RNA with DDA induced an influx of peritoneal cells. Furthermore, RNA with DDA activated macrophages as shown by, a.o., enhanced phagocytic activity and killing capacity forL. monocytogenes. The results suggest that the observed macrophage activation is probably T-cell-independent. With regard to the ribosomal vaccine ofP. aeruginosa it is concluded that RNA also contributed to the protective activity by increasing the humoral response against suboptimal concentrations of contaminating cell surface antigens. In conclusion, it is proposed that ribosomal vaccines may be considered as a combination of a non-specific immunomodulator (RNA) with pathogen-specific cell surface antigens. This concept of ribosomal vaccines is discussed in relation to the literature concerning RNase-sensitive ribosomal vaccines.     

Characterization of the ribosomal DNA units in two related Prunus species (P. Cerasifera and P. Spinosa)

Summary The genetic relationships between two Prunus species, involved in rootstock breeding, were examined at the level of the ribosomal RNA genes. Twenty clones of P. cerasifera, a diploid species, and 12 clones of P. spinosa, a tetraploid wild species, were studied. The use of three heterologous ribosomal DNA probes covering different regions of the ribosomal tandem repeats enabled us to construct restriction maps for EcoRI and BamHI. We identified two unit types (unit I and unit II) in P. cerasifera. In P. spinosa, P. cerasifera units were present in addition to a third ribosomal unit type (unit III). These results appeared to confirm previous cytological studies (Salesses 1973) indicating that one of the genomes in P.spinosa has homology with the one from P. cerasifera.