Physical characterization of a glucose-dehydrogenase-bearing plasmid from ketoacid-producingErwinia herbicola

Erwinia herbicola (ATCC 21998), a facultative anaerobe, has two plasmids: pVQ1 and pVQ2. Curing with mitomycin C indicated that pVQ2 was cryptic but pVQ1, a 7.4-kb plasmid, bears a 4.3SacI fragment which strongly hybridized to the C-terminal region of the glucose dehydrogenase gene ofAcinetobacter calcoaceticus. A restriction map of plasmid pVQ1 is presented.The authors are with the Department of Biotechnology, Regional Research Laboratory, Canal Road, Jammu Tawi-180 001, India;     

Azadirachtin: I-interaction with the development of red cotton bugs

Azadirachtin, a material isolated from Azadirachta indica A. Juss, was applied to various stages of red cotton bugs (Dysdercus koenigii F.). The phytochemical evoked various specific and nonspecific effects during the course of development. Prolonged development, wing deformities unplasticisation of wing lobes, development of wingless adults and larval mortality were the characteristic features.

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Azadirachtine d'Azadirachta indica I: Interaction avec de développement de Dysdercus koenigii

Résumé L'azadirachtine, isolat de Azadirachta indica A. Juss a été utilisée (par traitement du substrat ou par dépôt sur l'insecte) sur un hétérométabole, Dysdercus koenigii F. Cette substance phytochimique provoque divers effets, spécifiques ou non, pendant le développement.Les modifications caractéristiques sont: un développement prolongé, de déformations alaires, une absence de plastification des bourgeons alaires, une production d'adultes sans ailes et une mortalité nymphale.De tels résultats suggèrent des études complémentaires pour mettre en évidence une hormone d'éclosion chez D. koenigii avec laquelle interférerait l'azadirachtine.

     

Glucofructosan biosynthesis in Fusarium oxysporum: Regulation and substrate specificity of fructosyl transferase and invertase

Mycelium of Fusarium oxysporum grown on a glucose-containing medium lacked fructosyl transferase and invertase activities. Synthesis of fructosyl t     

Plectranthoic acid,acetylplectranthoic acid and plectranthadiol,three triterpenoids from Plectranthus rugosus

Sitosterol and three new pentacyclic triterpenoids, plectranthoic acid, acetylplectranthoic acid and plectranthadiol, have been isolated from leaves of P. rugosus. From spectroscopic evidence and chemical behaviour the structure of plectranthoic acid was established as (19S)-3α-hydroxy-18α-urs-12-en-29β-oic acid and acetylplectranthoic acid is the 3α-acetyl derivative of this compound. Plectranthadiol is (19S)- 3α-hydroxy-18α-urs-12-en-29β-ol.     

Lipochromosome mediated gene transfer: Identification and probable specificity of localization of human chromosomal material and stability of the transferents

Summary Using lipochromosomes (phospholipid-entrapped chromosomes) we have transferred the human HGPRT gene into HGPRT deficient mouse cells (A9) with a frequency of approximately 1×10⁻⁵ (Mukherjee et al., Proc. Natl. Acad. Sci. USA 75: 1361–1365; 1978). Two other genes located on the long arm of the human X-chromosome were also expressed in two independently derived populations of transferents (A9/GT3 and A9/GT4). We report here the chromosomal and enzymatic composition of human HGPRT-positive clones from each subpopulation analyzed in detail with alkaline Giemsa-11 staining. All the clones expressed human PGK and HGPRT, but one (A9/GT4C6) lacked human G6PD. In each of four clones examined microscopically, a small piece of presumptive human chromatin was visible in the karyotypes of most cells. The chromatin fragment was free or attached in each cell of an individual clone. When integrated, the human chromosomal fragment in each clone appeared associated with the centromere of the same telocentric A9 chromosome (No. 6 by Q-banding). These data suggest that: (a) substantial human chromosomal fragments can be transferred into recipient cells using the lipochromosome technique; (b) clones from human HGPRT positive A9 transferent subpopulations may or may not possess other human X-linked markers; (c) the stability of lipochromosomally transferred genes varied from clone to clone and stability is generally poor in the absence of continuous selection pressure (e.g., HAT); (d) when multiple X-linked human genes were transferred to mouse cells a cytologically detectable human chromosomal fragment was identified free or attached to a host chromosome; and (e) integration of transferred human chromosomal material into mouse chromosomes may occur at preferential site(s) in the recipient genome. This research was sponsored in part by the Office of Health and Environmental Research U.S. Department of Energy under Contract W-7405-eng-26 with the Union Carbide Corporation.     

Developmental Expression of HNK-1-Reactive Antigens in Rat Cerebral Cortex and Molecular Heterogeneity of Sulfoglucuronylneolactotetraosylceramide in CNS Versus PNS

Monoclonal antibody HNK-1 reacts with a carbohydrate epitope present in proteins, proteoglycans, and sulfoglucuronylglycolipids (SGGLs). On high-performance TLC plates, SGGLs of the CNS from several species migrated consistently slower than those from the PNS, a result indicating possible differences in the structures. The structural characteristics of the major SGGL, sulfoglucuronylneolactotetraosylceramide (SGGL-1), from CNS was compared with those of SGGL-1 from PNS. Although the composition, sequence, and linkages of the carbohydrate moiety of the SGGL-1 species were identical, SGGL-1 from CNS contained mainly short-chain fatty acids, 16:0, 18:0, and 18:1, amounting to 85% of the total fatty acids, whereas SGGL-1 from PNS contained large proportions (59%) of long-chain fatty acids (greater than 18:0). These differences in the fatty acid composition accounted for the different migration pattern observed. The developmental expression of SGGLs and HNK-1-reactive proteins was studied in rat cerebral cortex between embryonic day (ED) 15 to adulthood. SGGLs in the rat cortex were maximally expressed around ED 19 and almost completely disappeared by postnatal day (PD) 20. This expression was contrary to their increasing expression in the cerebellum and sciatic nerve with postnatal development. Six to eight protein bands with a molecular mass of greater than 160 kDa were HNK-1 reactive in the rat cerebral cortex at different ages. The major HNK-1 reactivity to the 160-kDa protein band seen in ED 19 to PD 10 cortex decreased and completely disappeared from the adult cortex, whereas several other proteins remained HNK-1 reactive even in the adult. Western blot analyses of the neural cell adhesion molecules (N-CAMs) during development of the rat cortex with a polyclonal anti-N-CAM antibody showed that the major HNK-1-reactive protein bands were not N-CAMs. Between PD 1 and 10, 190-200-kDa N-CAM was the major N-CAM, and between PD 15 to adulthood, 180-kDa N-CAM was the only N-CAM present in the rat cortex.     

Metabolism of very low density lipoproteins--effect of sardine oil.

The effect of feeding fish oil on the metabolism of lipoproteins was studied in rats. Rats were fed diet containing 10% sardine or groundnut oil for 6 weeks. There was a significant decrease in the total cholesterol, phospholipids and triglycerides as well as the amount of the lipids associated with VLDL and LDL in serum in fish oil-fed rats. The synthesis and secretion of lipoproteins particularly apoB containing lipoproteins by primary cultures of hepatocytes from these rats were studied by 14(C)-acetate or 3(H)-leucine labelling. Primary cultures of hepatocytes derived from sardine oil-fed rats showed reduced incorporation of 3(H)-leucine into apoB containing lipoproteins secreted into the medium when compared to those fed groundnut oil, indicating a decreased synthesis and secretion of apoB. This was further confirmed by significantly lower incorporation of 14(C)-radioactivity into total and individual lipids of VLDL secreted into the medium, as well as that associated with different lipids in cell layer. The activity of lipoprotein lipase in adipose tissue and aorta was significantly higher in rats fed sardine oil which may cause an increased clearance of triglyceride-rich lipoproteins from circulation. These results indicate that the fish oil exerts hypolipidemic effect particularly by decreasing the synthesis and secretion of VLDL by liver and possibly by an increased clearance of triglyceride-rich lipoproteins from circulation.     

Oxalate binding to rat intestinal brush-border membrane in pyridoxine deficiency: a kinetic study

Oxalate bound specifically to the intestinal brush-border membrane (BBM) of pyridoxine-deficient rats, but not to BBM of control rats. The binding of oxalate to intestinal BBM of pyridoxine-deficient rats was rapid, reversible, dependent on concentration of oxalate, temperature sensitive and competitively inhibited by oxalate analogues. Kinetic analysis of the oxalate binding data revealed induction of two distinct classes of receptor site for oxalate. The high-affinity oxalate binding sites, reached saturation at 60-70 nM oxalate, had a Kd of 24.29 nM and the number of binding sites were 30 pmoles (i.e., 1.8.10(13) molecules). The low-affinity oxalate binding sites, could not be saturated under experimental conditions upto 1 microM oxalate. It had a Kd of 487.5 nM and the number of binding sites were 156 pmoles (i.e., 9.4.10(13) molecules). The apparent energy of activation was 19 kcal/mol. The half-saturation concentration of inhibitor (IC50) of oxalate was 0.4.10(-5) M, while all other structural analogues of oxalate had higher IC50 values. Among the competitive inhibitors tested IC50 was in the following order, pyruvate greater than maleate greater than oxaloacetate greater than glyoxylate greater than parabonate greater than oxalate. These kinetic characteristics indicate involvement of a membrane protein in oxalate binding and transport in rat intestinal brush-border membrane in pyridoxine deficiency.     

Cystinotic and normal fibroblasts: Differential susceptibility to cysteine toxicity in vitro

Summary Extracellular cysteine concentrations between 0.5 and 2.5 mM resulted in death of normal but not cystinotic cells grown in Eagle's minimal essential medium containing supplemental fetal bovine serum and antibiotics. Differential cell survival was determined by viable cell counting using Trypan Blue dye exclusion. In cocultivation experiments of [³H]thymidine-labelled cystinotic fibroblasts with nonradioactive normal fibroblasts, autoradiography confirmed the selective survival of cystinotic cells in medium containing 1 mM cysteine. At this concentration of 1 mM cysteine, intracellular cystine content increased slightly in surviving normal cells but not in cystinotic cells, which normally contain a high level of intracellular cystine. This comparative resistance of cystinotic fibroblasts to elevated extracellular cysteine concentrations forms the basis for an in vitro selective system for these mutant human cells. Further exploration of this resistance phenomenon may well expand the understanding of the molecular defect in cystinotic cells.