A new oralMycoplasma isolated from the tonsils of two patients suffering from scarlatina

From the tonsils of 38 patients suffering from scarlatina and undergoing a penicillin treatment, no L forms of streptococci could be obtained.From the tonsils of two patients two strains of a newMycoplasma were isolated.Growth characteristics and antigenic structure of these strains differ from previously isolated human strains. We could not identify them with any animal strains.The sameMycoplasma was isolated from a tissue culture of human embryonic lung originally received from Dr. Davis (U.S.A.).     

The influence of hopanoids on growth of Mycoplasma mycoides

Hopane glycolipid, isolated from Bacillus acidocaldarius, was studied in its ability to support growth from Mycoplasma mycoides var. capri as substitute for sterols. All attempts to culture Mycoplasma on hopane glycolipid failed. When added together with cholesterol, the effect of HGL was a reduction in growth rate.The hopanoid diplopterol moderately supported growth of Mycoplasma. This effect was strikingly enhanced in diplopterol adapted cultures. Application of diplopterol via dipalmitoyl-phosphatidylcholine liposomes resulted in an improved growth rate. These results suggested that diplopterol can fullfill sterol function in Mycoplasma membranes.Abbreviations HGL Hopane glycolipid 1-(O--N-acylglucosaminyl)-2,3,4-tetrahydroxypentane-29-hopane - diplopterol 22-hydroxy-hopane - DPPC dipalmitoyl-phosphatidylcholine - PC phosphatidylcholine     

Microorganisms of thePleuropneumonia group (family ofMycoplasmataceae) in man

Summary Sixty one strains of pleuropneumonia-like organisms (P.P.L.O.) have been isolated in man: 25 from the discharge of patients with urogenital disorders, 13 from women who were pregnant or who had borne a child 6 weeks previously. In women the frequency of positive cultures increased with the disappearance of Lactobacilli. Twenty three strains were cultivated from the buccal mucosa of 27 healthy subjects. Classification by means of cultural appearance and biochemical behaviour allowed of differentiation into 4 groups, three of which were in conformity with three species ofMycoplasma described byEdward andFreundt. The only difference as compared with this latter classification is that with our methodM. fermentans andM. salivarius regularl gave clearcut hemolysis, which was not found byEdward. Two urogenital strains which grew well on not specially enriched media could not be identified.     

Fatty acid composition of membranes of L-forms ofStreptococcus faecalis andProteus mirabilis cultured at different osmolalities

The fatty acid composition of membranes of L-forms ofStreptococcus faecalis andProteus mirabilis cultured at different osmolalities and in different osmotic stabilizers was examined.S. faecalis L-forms cultured with sucrose in the medium showed a decrease in the unsaturated fatty acid C₁₈₁ and an increase in the C₁₈ fatty acid and C₁₉ cyclopropane fatty acid. Fatty acid composition ofS. faecalis L-forms cultured in medium containing 1.8% NaCl was similar to the fatty acid composition of L-forms cultured in brain-heart infusion broth (BHI) without osmotic stabilizer and was between the composition of fatty acids of L-forms in BHI with sucrose and that in BHI without 0.5 M sucrose. InProteus mirabilis L-forms, there were differences between L-forms cultured with and without sucrose, but these differences were not comparable to the changes observed inS. faecalis L-forms.P. mirabilis L-forms cultured with and without NaCl in the medium had similar fatty acid compositions.     

Insertion mutations at the maizeOpaque2 locus induced by transposable element familiesAc, En/Spm andBg

Eight independently isolated unstable alleles of theOpaque2 (O2) locus were analysed genetically and at the DNA level. The whole series of mutations was isolated from a maize strain carrying a wild-typeO2 allele and the transposable elementActivator (Ac) at thewx-m7 allele. Previous work with another unstable allele of the same series has shown that it was indeed caused by the insertion of anAc element. Unexpectedly, the remaining eight mutations were not caused by the designatedAc element, but by other insertions that are structurally similar or identical to one of two different autonomous transposable elements. Six mutations were caused by the insertion of a transposable element of theEnhancer/Suppressor-Mutator (En/Spm) family. Two mutations were the result of the insertion of a transposable element of theBergamo (Bg) family. Genetic tests carried out with plants carrying the unstable mutations demonstrated that all were caused by the insertion of an autonomous transposable element.     

Arginine and proline genes ofAspergillus niger

Summary Aspergillus niger mutants defective in arginine or proline biosynthesis have been isolated and 12 genetic loci were identified. Mutation was induced by low doses UV, and mutants were isolated after filtration enrichment. The mutants were classified according to their phenotype in growth tests and were further characterized in complementation tests. The arginine auxotrophic mutants represent nine complementation groups. Three additional complementation groups were found for mutants that could grow on proline (two of them on arginine too). Linkage group analysis was done in somatic diploids obtained from a mutant and a master strain with genetic markers on six chromosomes. Thearg genes belong to six different linkage groups and thepro genes to two. Onearg-mutant could be complemented by transformation with theA. nidulans arg B ⁺ gene, and thisA. niger gene thus appeared to be homologous to theA. nidulans arg B. We isolated anA. niger strain with theargB gene tightly linked with thenicA1 marker. This strain is very suitable as acceptor for transformation with anargB-plasmid, because transformants with inserts on the homologous site can be recognized and analyzed genetically using thenicA1 marker gene.     

L-forms ofHaemophilus influenzae: Growth and reversion as influenced by a strain ofNeisseria perflava

Factors excreted into the medium by various bacteria and fungi exert a significant effect on the growth and revertibility of bacterial L-forms. Studies with L-forms ofHaemophilus influenzae have been facilitated by a strain ofNeisseria perflava, which not only promotes the growth of the L-forms on media of normal osmolarity (horse blood agar), but also enhances the revertibility of the L-forms to the parent bacterium. L-forms derived fromN. perflava also exhibit this growth-enhacing property, an effect that does not appear to be related to X and V factors. Preliminary characterization of the active component produced byNeisseria perflava indicates that it is present in broth filtrate, diffusible through agar, heat labile, and of large molecular size.     

Altered mitochondrial ribosomes in a cold-sensitive mutant of Saccharomyces cerevisiae

A mutation at a new locus denotedtsr1 which lies very close to theery1 locus and 21S rRNA gene in mitochondrial DNA ofSaccharomyces cerevisiae, confers conditional respiratory deficiency on cells grown at low temperature, namely 18°. Studies on mitochondria isolated from a strain carrying the mutatedtsr1 locus demonstrate that the rate of mitochondrial protein synthesis is cold-sensitive at 18°. The large subunit of the mitochondrial ribosomes isolated from the mutant strain is unstable during extraction and the isolated ribosomes are shown to be defective in catalyzing the poly U-directed synthesis of polyphenylalanine. It is concluded that thetsr1 locus is involved in the determination of the properties of the large subunit of the mitochondrial ribosome.     

Alterations of the L-forms of a sporebearing bacillus

A large pleomorphic gram-negative bacillus developed as a contaminant on blood-agar. Spores were formed in one culture. L-forms were produced with penicillin on blood-agar with 2.5% NaCl; they grew well when transplanted to agar with 0.5% NaCl. After several transplants and long incubation of the L-forms without penicillin, in three transplants small gram-negative pleomorphic bacilli grew, but no L-forms. This occurred once on blood-agar and twice on 30% gelatin. The growth obtained from these small bacilli was similar in morphology and in the physical properties of the organisms to the altered L-forms of Proteus and Salmonella. Multiplication of the pleomorphic organisms and development of branching filaments from the round forms was apparent. The original large gram-negative bacillus was regularly recovered from the L-forms, and was recovered several times from the descendants of the small bacilli. These observations are essentially similar to those made with L-forms of Proteus and with an L-form studied in 1952, indicating alterations in L-forms of bacteria which do not produce B type L-forms.     

A ribosomal RNA gene ofEscherichia coli (rrnD) on λ daroE specialized transducing phages

Summary Lambda-transducing phages carrying segments of theEscherichia coli chromosome in thearoE-trkA region have been isolated and shown by hybridization to carry an rRNA gene (rrnD). The most likely gene order istrkA aroE rrnD. TheEcoRI andSmaI endonuclease cutting pattern of therrnD gene is identical with the one ofrrnB, but differented fromrrnC.     

Overall similarity and DNA base composition of someAcinetobacter strains

Six namedAcinetobacter anitratus and 23 namedA. lwoffii strains, most of them isolated in Hungary, were numerically analyzed. A set of 56 selected, distinctive features was used. All features giving an identical response were omitted. There are three interrelated groups. One group contains all of theA. anitratus and one of theA. lwoffii strains; it is largely glucidolytic and nearly all strains have 42.5±0-5 % GC. The second group consists ofA. lwoffii strains with % GC values below 43. The third and largest group containsA. lwoffii strains with % GC between 44.5 and 47. There are no sharp boundaries between the three groups.     

Phylogenetic measurement in procaryotes by primary structural characterization

Summary Oligonucleotide cataloguing has been used to characterize a number of 5S RNA species from various Procaryotes. Such catalogs can be used to establish certain and detailed phylogenetic relationships among organisms. Confining attention at present to four Families of Procaryotes, theEnterobacteriaceae, theBacillaceae, theAchromobacteraceae, and thePseudomonadaceae, we have shown that the conventionally accepted classification of these organisms which places the first three in the orderEubacteriales, and the last in the orderPseudomonadales, is not phylogenetically valid.     

Genetic analysis of a lactococcal plasmid replicon

Summary The sequence and genetic organization was determined of the 2508 by lactococcal portion of pFX2, which was derived from a crypticLactococcus lactis subsp.lactis plasmid and used as the basis for construction of a series of lactococcal vectors. A lactococcal plasmid plus origin and two replication protein-coding regions (repA andrepB) were located. RepA has a helix-turn-helix motif, a geometry typical of DNA-binding proteins. RepB shows a high degree of homology to the plasmid replication initiation proteins from other gram-positive bacteria andMycoplasma. The transcribed inverted repeat sequence betweenrepA andrepB could form an attenuator to regulate pFX2 replication. Upstream of theori site, and in a region which was non-essential for replication, a 215 by sequence identical to the staphylococcal plasmid pE194 and carrying the RS_A site was identified. The genetic organization of this lactococcal plasmid replicon shares significant similarity with pE194 group plasmids.     

Studies on the Minimum Reproducible Unit of Staphylococcal L-Forms

The minimum size of a reproducible unit of staphylococcal L-forms was determined by filtration and electron microscopic methods. Ultrathin sections of an induced strain of Staphylococcal L-forms (STA-EMT-1) in liquid medium revealed several types of structures, all of which were bound by a single membrane and most of which possessed ribosome-like granules. Many of the small granules were less than 0.3 μm and were attached to the membrane of the large bodies. Using a serial filtration method, it was observed that viable L-forms were still detected in 0.22 μm filtrate, but the viable cell count of L-forms decreased in number with the decrease in pore size of membrane filters. A fractionation technique, using L-forms filtered through a membrane filter with a 0.45 μm pore size, revealed that there were three classes of small bodies but only the first class with ribosome-like granules over approximately 0.2 μm in diameter seems to be able to reproduce.     

L forms of Streptococcus in the cultures of blood from patients with rheumatic fever in the active and inactive phases

It was shown that L-forms of streptococci were constantly isolated by means of the method used by the authors from patients with rheumatism, irrespective of the activity and the course of the disease. The data obtained pointed to the presence of septicemia caused by the L-forms of streptococci in patients with rheumatism both at the active and inactive phase. In this connection it should be noted that modern clinical criteria of the activity of rheumatic process are unreliable.     

The genome of the non-cultured,bacterial-like organism associated with citrus greening disease contains thenusG-rplKAJL-rpoBC gene cluster and the gene for a bacteriophage type DNA polymerase

We have recently cloned three DNA fragments (In-2.6, In-1.0, and In-0.6) of the noncultured, bacterial-like organism (BLO) associated with citrus greening disease. Nucleotide sequence determination has shown that fragment In-2.6 is part of therplKAJL-rpoBC gene cluster, a well-known operon in eubacteria. The DNA fragment upstream of and partially overlapping with In-2.6 could be isolated and was shown to be thenusG gene. InEscherichia coli, nusG is also immediately upstream ofrplKAJL-rpoBC. Fragment In-1.0 carries the gene for a bacteriophage type DNA polymerase. Fragment In-0.6 could not be identified.When In-2.6 was used, at high stringency, as a probe to detect greening BLO strains in infected plants, hybridization was obtained with all Asian strains tested, but not with the African strain examined. At lower stringencies, In-2.6 was able to detect also the African strain. The implications of these reults in the taxonomical position of the greening BLO are discussed.     

Cloning,sequence and expression of the gene coding for rhamnogalacturonase ofAspergillus aculeatus; a novel pectinolytic enzyme

Rhamnogalacturonase was purified from culture filtrate ofAspergillus aculeatus after growth in medium with sugar-beet pulp as carbon source. Purified protein was used to raise antibodies in mice and with the antiserum obtained a gene coding for rhamnogalacturonase (rhgA) was isolated from a λ cDNA expression library. The clonedrhgA gene has an open-reading frame of 1320 base pairs encoding a protein of 440 amino acids with a predicted molecular mass of 45 962 Da. The protein contains a potential signal peptidase cleavage site behind Gly-18 and three potential sites forN-glycosylation. Limited homology withA. niger polygalacturonase amino acid sequences is found. A genomic clone ofrhgA was isolated from a recombinant phage λ genomic library. Comparison of the genomic and cDNA sequences revealed that the coding region of the gene is interrupted by three introns. Furthermore, amino acid sequences of four different peptides, derived from purifiedA. aculeatus rhamnogalacturonase, were also found in the deduced amino acid sequence ofrhgA.A. aculeatus strains overexpressing rhamnogalacturonase were obtained by cotransformation using either theA. niger pyrA gene or theA. aculeatus pyr A gene as selection marker. For expression of rhamnogalacturonase inA. awamori theA. awamori pyrA gene was used as selection marker. Degradation patterns of modified hairy regions, determined by HPLC, show the recombinant rhamnogalacturonase to be active, and the enzyme was found to have a positive effect in the apple hot-mash liquefaction process.     

Only C-2 specific glucose oxidase activity is expressed in ligninolytic cultures of the white rot fungus Phanerochaete chrysosporium

Hydroxylamine oxidation was measured in four recently isolated heterotrophic nitrate-reducing bacteria belonging to the generaPseudomonas, Moraxella, Arthrobacter andAeromonas. A hydroxylamine-cytochromec oxidoreductase activity was detected in periplasmic fractions of thePseudomonas andAeromonas spp. and in total soluble fractions of theArthrobacter sp. A monomeric 19-kDa non-haem iron hydroxylamine-cytochromec oxidoreductase was purified from thePseudomonas species and shown to be similar to hydroxylaminecytochromec oxidoreductase ofParacoccus denitrificans.Abbreviations AMO Ammonia monoxygenase - HAO Hydroxylamine-cytochromec oxidoreductase