Dietary hexachlorocyclohexane induced changes in blood and liver lipids in albino mice.

Dietary intake of technical hexachlorocyclohexane (HCH) by albino mice for 2 weeks (at 400 and 800 ppm) resulted in hyperlipemia. Significant increase in triglycerides, phospholipids and cholesterol fractions of blood was observed in these animals. Dietary intake of gamma-isomer of HCH for 2 weeks (at 200 ppm) did not have any effect on blood lipid profile, but at 400 ppm level produced higher contents of phospholipids and cholesterol. The hepatomegaly produced by dietary technical HCH or gamma-HCH was not accompanied by fatty metamorphosis of liver. Hypertriglyceridemia caused by HCH was accompanied by lower triglyceride levels in liver, suggesting a possible higher rate of secretion from liver.     

Superoxide anion radical induces lipid phase transitions that mimic temperature-induced phase-transition phenomenon of membrane lipids

A biological membrane is shown to undergo lipid-phase transition leading to increased membrane fluidity when exposed to extraneously generated superoxide anion radical. This phase-transition is several folds higher in magnitude when compared to the temperature-induced fluidity change at the transition temperatures. This finding could have significant importance since an altered membrane configuration may involve aspects of biochemistry, biophysics or physiology.     

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.     

Dark requirement for cell regeneration and colony formation by mesophyll protoplasts ofNicotiana plumbaginifolia Viv.

Summary The protoplasts ofNicotiana plumbaginifolia required darkness for cell regeneration and colony formation. Maximal plating efficiency of the protoplasts could be achieved by keeping the cultures in dark instead of light or dark/light sequence. Only two days of darkness prior to the illumination at 400 or 3,000 lux resulted in appreciable plating efficiency, than those of light from the beginning, but these values could not match the high plating efficiency in total darkness.     

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.