The cloning and expression of transfer RNA gene cluster of Vibrio eltor phage e4

Vibrio eltor phage e4 codes for five different tRNA species (S. Chattopadhyay and R. K. Ghosh, 1988, Virology, 165, 606-608). The tRNA genes contained in a 3.4-kb KpnI fragment (S. Chattopadhyay and R. K. Ghosh, 1988, Virology, 162, 337-345) have been cloned in pUC 19 at the KpnI site. Two recombinant plasmids, pSR216 and pSR112, produced four of the five tRNA species (arginine, isoleucine, tyrosine, and tryptophan) encoded in the phage genome. The tRNA genes were located on a 1.45-kb KpnI-HindIII subfragment.

Toxin profiles of Vibrio cholerae non-O1 from environmental sources in Calcutta, India

A collection of Vibrio cholerae non-O1 isolated from the aquatic environs of Calcutta, a cholera-hyperendemic area, were examined for the production of cholera toxin (CT), Shiga-like toxins (Vero toxins), heat-stable enterotoxin, and hemolysins. Two (0.5%) V. cholerae non-O1 isolates produced CT. The DNA from both these isolates also hybridized with a DNA probe containing sequences encoding the A subunit of CT. None of the strains produced Shiga-like toxins or heat-stable enterotoxin. Hemolytic activity was observed in 89.7% of the strains, of which 36.1% exhibited biological activity in the suckling mouse. However, none of them produced a hemolysin that cross-reacted with the thermostable direct hemolysin of Vibrio parahaemolyticus. It appears from this study that a small percentage of environmental V. cholerae non-O1 strains do possess the potential for causing cholera-like diarrhea.

Characterization of phage-specific transfer RNA molecules coded by Vibrio eltor phage e4

Transfer RNAs were isolated from phage e4-infected Vibrio eltor Mak 757 cells. These were aminoacylated with 14 individual 3H-labeled L-amino acids. Hybridization of these [3H]aminoacyl-tRNAs with phage e4 DNA revealed that the phage e4 encodes tRNAs for arginine, tryptophan, tyrosine, leucine, and isoleucine. Direct aminoacylation of phage-coded tRNA molecules isolated from phage DNA-RNA hybrids also confirmed this observation.

Localization of transfer RNA genes on the physical map of Vibrio eltor phage e4 genome

Transfer RNAs were isolated from uninfected and phage e4-infected Vibrio eltor Mak 757 cells. These tRNAs were then aminoacylated with 3H-labeled amino acids and hybridized to DNA isolated from phage e4. Significant hybridization was observed only with tRNA isolated from phage e4-infected cells. Restriction enzyme digestion of phage e4 DNA followed by Southern blot using [32P]tRNA from infected cells revealed that tRNA genes were contained in a 3.4-kb Kpnl fragment. The tRNA genes were located on the physical map of the phage genome 19 kb from one of the termini.

Characterization of Vibrio eltor typing phages: properties of the Eltor phage e4

Biophysical characteristics of Vibrio eltor phage e4, a key phage in the Vibrio cholerae typing scheme were studied. This icosahedral phage was found to contain 12 structural polypeptides with mol. wt. ranging from 25,000 to 120,000. One of these polypeptides of mol. wt. 50,000 accounted for most of the structural proteins present and was probably the major phage capsid protein. The phage genome comprised a single linear, double-stranded DNA molecule, 69.2 kbp in length (45.6 X 10(6) mol. wt.) as determined by electron microscopy and restriction fragment analyses. The G + C content was 34.6%. Electron microscopy data indicated that unlike the DNAs of other cholera phages, phage e4 DNA is not circularly permuted. Adsorption under normal conditions was biphasic with rate constants of 1.02 X 10(-9)/ml/min up to 60% adsorption and 3 X 10(-10)/ml/min thereafter. Intracellular phage multiplication was characterized by a latent period of 27 min. The burst size was approximately 100 phage particles per infected cell.

Plant regeneration from shoot callus of rosewood (Dalbergia latifolia Roxb.)

In vitro propagation of trees using cell, tissue and organ culture is a fast emerging area. We report here the clonal propagation of Indian rosewood (Dalbergia latifolia Roxb.) from shoot callus cultures of 5 year old trees. Bud regeneration was obtained on MS media supplemented with BA and NAA. About 35% of the cultures showed organogenesis. Shoots measuring about 3-5 cm can be excised and rooted in White's medium supplemented with 1-2 mg/L IAA. Rooted plants were successfully established in soil.

Effect of ectopic pituitary homograft on the physiological status of rat testis

Pituitary glands grafted under the kidney capsule provide a continuous supply of prolactin due to the absence of hypothalamic inhibitory factor. Increase in the level of prolactin in the rat may affect availability of hormone for reproductive function. Single pituitaries were transplanted under the kidney capsule of male rats. After six weeks of the transplant, the recipient rats were sacrificed and trophic activity of testosterone and intratesticular functions were assessed. The weights of ventral prostate and seminal vesicles, full and empty, showed significant increase from the control value. The activity of beta-glucuronidase in kidney, an androgen inducible enzyme, also increased in comparison with the control value. Incorporation of 32P in the nucleic acid fraction showed an increase. The increased rate of testosterone production and an alteration in spermatogenesis was associated with increased activity of acid phosphatase and decreased activity of beta-glucuronidase. The active mediation of lysosomal enzyme in testicular function as altered by prolactin was indicated.

Effect of intratesticular administration of serum on the physiological status of rat testis

The effect of loss of integrity of seminiferous tubules on intracellular mechanisms in the testis of rats was studied after intratesticular administration of homologous serum. The increased weights of ventral prostate, seminal vesicles and increased activity of beta glucuronidase in kidney reflected an increased availability of testosterone to the target organs. The pulse labelling of 32P in the nucleic acid fraction of testis was significantly increased. The concentration of testicular DNA was increased while the ascorbic acid was slightly decreased. Activities of the lysosomal enzymes, acid phosphatase and beta glucuronidase increased. The involvement of lysosomal enzymes in the testicular function under altered condition was indicated.

Involvement of lysosomal enzymes in flutamide-induced stimulation of rat testis

Flutamide, an antiandrogen, increases the levels of plasma luteinizing hormone (LH), stimulates steroidogenesis in the testis and antagonizes the biological expression of androgen on target organs. flutamide was administered to rats to study intracellular mechanism in the testis where steroidogenesis was stimulated in the presence of an antiandrogen. The weights of ventral prostate and seminal vesicles showed antiandrogenic effects of flutamide. However, the availability of testosterone was reflected by the increased activity of kidney beta glucuronidase. The weight of testis and the incorporation of 32P in its nucleic acid fraction at 45 minutes were increased. The concentrations of testicular DNA and ascorbic acid were decreased. Activity of the lysosomal enzymes, acid phosphatase and beta glucuronidase, increased in the free state. Thus flutamide provided a condition where changes in the lysosomal stability in association with the alteration of testicular function was demonstrated.

Justicisaponin-I, a new triterpenoid saponin from Justicia simplex

A new triterpenoid saponin, named justicisaponin-I, has been isolated from Justicia simplex D. Don. (Acanthaceae). It has been assigned oleanolic acid-3-O-beta-D-glucopyranosyl-4'-O-ferulate structure (1) on the basis of chemical transformation and comprehensive spectral evidence. Justicisaponin-I has produced significant sperm acrosomal membrane stabilizing action and may prove to be a potent antifertility agent.

An improved 11 alpha-hydroxylation of progesterone by Aspergillus ochraceus TS

1. The stereospecific hydroxylation of progesterone exclusively to its 11 alpha-hydroxy derivative by Aspergillus ochraceus TS is reported. 2. There is no secondary metabolite (6beta, 11 alpha-dihydroxyprogesterone) formed even when the transformation was attempted with different concentrations of the substrate (200 microgram/ml-200 mg/ml) for prolonged with Zn2+ at a concentration of 50 microgram/ml identical results were obtained. 3. Similar results were also obtained at different pH values of the culture medium.

High-molecular-weight RNAs of AKR, NZB, and wild mouse viruses and avian reticuloendotheliosis virus all have similar dimer structures

Several 50 to 70S tumor viral RNAs have previously been shown by electron microscopy to be dimers, with the two monomer subunits joined near their 5' ends. Five additional naturally occurring type C RNA tumor viruses have now been examined: AKR, and endogenous murine ecotropic virus; NZB, an endogenous murine xenotropic virus; and ecotropic and an amphotropic virus isolated from a wild mouse; and the avian reticuloendotheliosis virus (REV). All five 50 to 70S RNAs have similar 5'-to-5' dimer structures. Therefore, the observations support the hypothesis that the dimer linkage is a structural feature common to all type C mammalian viruses. REV is the first example of an avian virus with a clear 5'-to 5' dimer linkage. All of the mammalian viral RNAs, but not REV, showed symmetrically placed loops in each subunit of the dimer. Possible molecular structures and biological functions of the dimer linkages and loops are discussed.