Haploid plant regeneration from unpollinated ovule cultures of niger (<Emphasis Type="Italic">Guizotia abyssinica</Emphasis> (L. f.) Cass.)

Haploid plants were regenerated in vitro from unpollinated ovules of niger (Guizotia abyssinica (L. f.) (Cass.) on Murashige and Skoog nutrient medium (MS) supplemented with 10 μM naphthaleneacetic acid or 10 μM NAA + 1.5 μM kinetin and 30 g/l sucrose. Gamborg (B5) medium was the best for plant regeneration (in comparison with MS, Nitsch and Nitsch (NN), and Chu (N6) media) from cultured ovules, and 6.66 and 7.33 ovules of JNC-6 and Ootacamund cultivars were involved in direct plant regeneration on this medium. Matured ovules (ovules collected one day before anthesis or on the day of anthesis) only responded to cultural regimes and involved in direct plantlet development. Cytological preparation of root tips and chloroplast counts in the guard cells of leaf stomata of regenerated plants confirmed their haploid nature. This text was submitted by the authors in English.     

DNA-Launched Alphavirus Replicons Encoding a Fusion of Mycobacterial Antigens Acr and Ag85B Are Immunogenic and Protective in a Murine Model of TB Infection

There is an urgent need for effective prophylactic measures against Mycobacterium tuberculosis (Mtb) infection, particularly given the highly variable efficacy of Bacille Calmette-Guerin (BCG), the only licensed vaccine against tuberculosis (TB). Most studies indicate that cell-mediated immune responses involving both CD4+ and CD8+ T cells are necessary for effective immunity against Mtb. Genetic vaccination induces humoral and cellular immune responses, including CD4+ and CD8+ T-cell responses, against a variety of bacterial, viral, parasitic and tumor antigens, and this strategy may therefore hold promise for the development of more effective TB vaccines. Novel formulations and delivery strategies to improve the immunogenicity of DNA-based vaccines have recently been evaluated, and have shown varying degrees of success. In the present study, we evaluated DNA-launched Venezuelan equine encephalitis replicons (Vrep) encoding a novel fusion of the mycobacterial antigens α-crystallin (Acr) and antigen 85B (Ag85B), termed Vrep-Acr/Ag85B, for their immunogenicity and protective efficacy in a murine model of pulmonary TB. Vrep-Acr/Ag85B generated antigen-specific CD4+ and CD8+ T cell responses that persisted for at least 10 wk post-immunization. Interestingly, parenterally administered Vrep-Acr/Ag85B also induced T cell responses in the lung tissues, the primary site of infection, and inhibited bacterial growth in both the lungs and spleens following aerosol challenge with Mtb. DNA-launched Vrep may, therefore, represent an effective approach to the development of gene-based vaccines against TB, particularly as components of heterologous prime-boost strategies or as BCG boosters.     

Effect of continuous application of manures and fertilizers on rhizosphere microflora in arecanut palm

Summary The rhizosphere microflora of arecanut palm under continuous application of organic manures and inorganic fertilizers was studied. The nutrients applied are 100 g N, 40 g P₂O₅ and 140 g K₂O/palm/year in the form of organics and inorganics. The application of organic manure increased the microbial population. The increase in microbial population was observed between the rhizosphere samples collected at 0–30cm and 30–60 cm depths. The surface cultivation of soil increased the microbial population.Trichoderma sp. andAspergillus sp. dominated in therhizosphere of arecanut palm. Contribution No. 208. Central Plantation Crops Research Institute, Vittal-574243, Karnataka, India.     

Sporotrichum thermophile Growth, Cellulose Degradation, and Cellulase Activity

The activity of components of the extracellular cellulase system of the thermophilic fungus Sporotrichum thermophile showed appreciable differences between strains; β-glucosidase (EC 3.2.1.21) was the most variable component. Although its endoglucanase (EC 3.2.1.4) and exoglucanase (EC 3.2.1.91) activities were markedly lower, S. thermophile degraded cellulose faster than Trichoderma reesei. The production of β-glucosidase lagged behind that of endoglucanase and exoglucanase. The latter activities were produced during active growth. When growth was inhibited by cycloheximide treatment, the hydrolysis of cellulose was lower than in the control in spite of the presence of both endoglucanase and exoglucanase activities in the culture medium. Degradation of cellulose was a growth-associated process, with cellulase preparations hydrolyzing cellulose only to a limited extent. The growth rate and cell density of S. thermophile were similar in media containing cellulose or glucose. A distinctive feature of fungal development in media incorporating cellulose or lactose (inducers of cellulase activity) was the rapid differentiation of reproductive units and autolysis of hyphal cells to liberate propagules which were capable of renewing growth immediately.     

Metabolism of all-trans-retinol and all-trans-retinoic acid in rabbit tracheal epithelial cells in culture

As reported previously squamous cell differentiation of rabbit tracheal epithelial (RTE) cells in culture is a multi-step process. This program of differentiation is inhibited by retinoic acid and retinol; retinoic acid is about 100 times more effective than retinol. To examine the metabolism of these agents in this in vitro model system, RTE cells were grown in the presence of all-trans-[3H]retinol or all-trans-[3H]retinoic acid and their metabolites analyzed by high-pressure liquid chromatography. RTE cells converted most of the retinol to retinyl esters, predominantly retinyl palmitate. A small fraction was metabolized to polar compounds, one of which coeluted with retinoic acid. After methylation this compound eluted as 13-cis-methyl retinoate and as all-trans-methyl retinoate. Conversion to 13-cis-retinol was also observed. All-trans-retinoic acid was rapidly taken up by RTE cells and converted to more polar (peak 1) and less polar (peak 3) metabolites. A proportion of all-trans-[3H]retinoic acid was metabolized to 13-cis-[3H]retinoic acid. These metabolic reactions appeared to be constitutive and were not induced by pretreatment with retinoic acid. The peak 1 metabolites were rapidly secreted into the medium whereas the peak 3 metabolites were retained by the cells and were not detected in the medium. Alkaline hydrolysis of the metabolites in peak 3 yielded retinoic acid, indicating the formation of retinoyl derivatives. Our results establish that RTE cells can convert all-trans-retinol to 13-cis-retinol and retinoic acid. RTE can metabolize all-trans-retinoic acid to 13-cis-retinoic acid and to an unidentified ester of retinoic acid.     

Stabilization of cetyltrimethylammonium bromide permeabilized yeast whole cell lactase

Summary Cetyltrimethylammonium bromide-permeabilized cells ofK. fragilis loose -galactosidase activity due to leaking of the enzyme into the medium. This leakage of the enzyme can be prevented by storing the permeabilized cells either in buffer containing 50% glycerol or by treating the permeabilized cells with 0.2% glutaraldehyde at 4°C for 10 min. In repeated batch hydrolysis of lactose in milk, glutaraldehyde treated cells could be repeatedly used very efficiently.     

Alpha B-crystallin is expressed in kidney epithelial cell lines and not in fibroblasts

We have recently shown the presence of alpha B-crystallin in non-ocular tissues of diverse embryological origins such as the heart, brain, spinal cord, kidney, retina, etc. Using an alpha B-crystallin-specific antiserum and immunofluorescence, immunoblotting, immunoprecipitation and peptide mapping with Staphylococcus aureus protease, we demonstrate differential expression of alpha B-crystallin in epithelial and fibroblast cell lines. alpha B-Crystallin was detectable only in epithelial cell lines such as MDBK, MDCK, LLCPK1 and JTC-12, and was not observed in two kidney fibroblast cell lines, one skin fibroblast cell line, and one corneal fibroblast cell line. Differential expression of the alpha B-crystallin gene was also confirmed by Northern blot analysis of the RNAs isolated from these cell lines. These data suggest a cell-type-specific role for alpha B.