Age dependent alterations in phospholipid composition of a saprophytic and a pathogenic strain of Nocardia

Nocardia polychromogenes (saprophytic) and Nocardia asteroides (pathogenic) showed characteristic patterns in changes of cellular lipids during growth. Total lipids and total phospholipids decreased with the age of the culture in the saprophytic strain, whereas in the pathogenic strain total lipids increased throughout the culture period and the total phospholipids decreased in the late stationary phase. The decrease in total phospholipids in saprophytic strain was reflected in the individual phosphatides. In the pathogenic strain, the phosphatidylinositomannoside content doubled in early stationary phase. Differences were observed in fatty acid composition of phosphatides at various stages of growth, but the ratio of saturated to unsaturated fatty acids remained unaltered.     

Multiple immunoreplica Technique: screening for specific proteins with a series of different antibodies using one polyacrylamide gel

A simple method for immunological identification of proteins resolved electrophoretically is presented. Proteins from one polyacrylamide gel can be subjected to a series of electrophoretic transfers to nitrocellulose paper (partial “western-blots”), providing several replicas of the gel. Each replica can be reacted with a series of different antisera (at least three), where the preceding antibody is removed by treatment with pH 2.2. The antigen-antibody complexes are visualized using ¹²⁵I-Protein A. Reactivity and antigenic specificity of proteins immobilized on nitrocellulose paper is not affected by repeated incubations and low pH treatments. Identical size of the replicas and superimposable profiles of proteins detected by antibodies allow a precise localization of particular polypeptides in the original gel.     

FBJ murine osteosarcoma virus: identification and molecular cloning of biologically active proviral DNA

A 12.0-kilobase EcoRI restriction fragment containing FBJ murine osteosarcoma virus (FBJ-MSV) proviral DNA was identified in FBJ-MSV-transformed nonproducer rat cells and molecularly cloned in bacteriophage Charon 30 (lambda FBJ-1). A 5.8-kb HindIII fragment containing the entire FBJ-MSV proviral DNA was isolated from lambda FBJ-1 and subsequently subcloned in plasmid pBR322 (pFBJ-2). The DNA from recombinant plasmid pFBJ-2 was able to induce morphological transformation of rat fibroblasts in tissue culture. Transfected cells contained the p55 and p39 antigens specific for cells transformed by FBJ-MSV (T. Curran and N. M. Teich, J. Virol. 42:114-122, 1982). The organization of the FBJ-MSV provirus was analyzed by restriction endonuclease mapping, and a region of nonhomology with the helper virus was delineated. Sequences specific for this region (presumably the viral fos gene) were subcloned and used as a probe to identify related sequences present in the normal genomes of cells from a variety of mammalian species (cellular fos). A single-size (3.4 kilobases long) class of RNA hybridizing to the viral fos probe was identified in FBJ-MSV-transformed cells.     

Analysis of the env gene of a molecularly cloned and biologically active Moloney mink cell focus-forming proviral DNA.

A biologically active molecular clone of BALB/Moloney mink cell focus-forming (Mo-MCF) proviral DNA has been reconstructed in vitro. It contains the 5' half of BALB/Moloney murine leukemia virus (Mo-MuLV) DNA and the 3' half of BALB/Mo-MCF DNA. The complete nucleotide sequence of the env gene and the 3' long terminal repeat (LTR) of the cloned Mo-MCF DNA has been determined and compared with the sequence of the corresponding region of parental Mo-MuLV DNA. The substitution in the Mo-MCF DNA encompasses 1,159 base pairs, beginning in the carboxyl terminus of the pol gene and extending to the middle of the env gene. The Mo-MCF env gene product is predicted to be 29 amino acids shorter than the parental Mo-MuLV env gene product. The portion of the env gene encoding the p15E peptide is identical in both viral DNAs. There is an additional A residue in the Mo-MCF viral DNA in a region just preceding the 3' LTR. The nucleotide sequence of the 3' LTR of Mo-MCF DNA is similar to that of the 5' LTR of BALB/Mo-MuLV DNA with the exception of two single base substitutions. We conclude that the sequence substitution in the env gene is responsible for the dual-tropic properties of Mo-MCF viruses.     

Surface layers ofXanthomonas malvacearum,the cause of bacterial blight of cotton

Mureins were isolated from two strains ofXanthomonas malvacearum, a phytopathogenic bacterium causing bacterial blight of cotton. The purity of murein was 70–95 % and the amino acid and amino sugar components (glutamic acid, alanine, meso-diaminopimelic acid, muramio acid and glucosamine) were present at the molar ratio of 1: 1.9: 1: 1.12: 0.85. The bacterium secreted a copious amount of slime which masked its surface structure. The slime was composed of densely interwoven network of filamentous material originating from the cell surface and extended into the medium without any discernable boundary. The slime was secreted through surface layers pores by force, giving the effect of a spray or jet. Slime also played a role in chain formation of bacterial cells.     

E. coli membranes become permeable to ions following T7-virus-infection

Summary Infection of E. coli with the viruses T7 or T3 leads to a dramatic efflux of potassium ions. This ion efflux is caused by the virus particle since no concomitant protein synthesis is required. T7 mutants carrying deletions in the M-gene (Schweiger et al., 1975), however, yield virus particles disturbed in the ion release.     

Oral D2O administration and enzymatic changes in rat testis.

Heavy water caused marked gradual decrease in the weight of the body as well as the testes throughout the treatment interval ranging from 1 to 6 weeks. Following D2O oral administration, an overall significant fall in the activity of acid phosphatase and glucose-6-phosphatase was registered. On the other hand, the activity of lactic and succinic dehydrogenases, alkaline phosphatase and adenosine triphosphatase increases following D2O treatment. These changes in the enzyme activity are suggestive of an altered metabolism of the testes in response to D2O administration. Our data corroborate the view that biological systems do discriminate between H2 and D2.