Inhibition of protein and lipid synthesis in muscle by 2,4-dinitrofluorobenzene, an inhibitor of creatine phosphokinase

A photoaffinity label, 4-azidobenzoyltrimethionine has been synthesized. It competitively inhibits trimethionine uptake in the yeast C. albicans. Upon UV irradiation it irreversibly and specifically blocks oligopeptide uptake. These results give the first example of photoinhibition of peptide uptake in yeast.     

De novo organogenesis and plant regeneration in <Emphasis Type="Italic">Pongamia pinnata</Emphasis>, oil producing tree legume

Role of Thidiazuron (TDZ) in inducing adventitious organogenesis in Pongamia was studied. TDZ at different concentrations (0, 0.45, 2.27, 4.54, 6.71, 9.08, 11.35, 13.12 and 22.71 μM) were used for induction of caulogenic bud formation in deembryonated cotyledon explants. Each cotyledon was cut into three segments and identified as proximal, middle and distal. Duration of TDZ exposure, influence of the segment and orientation of the explant were studied. TDZ at 11.35 μM concentration was optimum for the induction of shoots and rapid elongation. Shoots induced at higher concentration elongated after several passages in growth regulator free medium, thereby extending the period of differentiation. Exposure of the explant for 20 days yielded more number of buds than 10 days. Proximal segment of the cotyledon was more responsive. Contact of abaxial surface in the medium was more effective and generated more buds than the adaxial side. Buds differentiated and elongated on transfer to MS basal medium for 8–12 passages of 15 days each. Rooting and elongation of shoots was achieved in charcoal supplemented half-strength MS medium. Rooted plantlets survived on transfer to sand soil mixture. The plants were hardened and transferred to green house. This is the first report on in vitro regeneration of Pongamia pinnata via adventitious organogenesis using TDZ. This protocol may find application in studies in genetic transformation, isolation of somaclonal variants and in induction of mutants. It also provides a system to study the inhibitory role of TDZ on shoot differentiation.     

Effect of chemical modification on the binding of gossypol by gossypin (11S protein) and congossypin (7S protein) of cottonseed

Binding of gossypol by gossypin and congossypin and their succinylated and sulfhydryl group-blocked derivatives has been measured. The binding by gossypin and congossypin is characterized by weak interaction. Succinylation of gossypin decreases the binding affinity whereas that of congossypin increases it. Blocking of sulfhydryl groups of both the proteins does not significantly affect gossypol binding, Succinylation dissociates gossypin and causes conformational changes whereas it does not dissociate congossypin but causes conformational changes. Sulfhydryl group blocking does not dissociate gossypin or congossypin, nor does it cause any conformational changes.     

Field response of chickpea to inoculation withGlomus versiforme

The response ofCicer arietinum to inoculation withGlomus versiforme under field conditions was investigated in a phosphorus deficient sandy loam soil. Inoculation with the mycorrhizal fungusGlomus versiforme increased the rate of VAM development in chickpea. The weight of nodules and the number of nodules per plant were higher in inoculated than in uninoculated plants. The phosphorus content of the shoots and its total uptake, were increased by either the application of single super-phosphate, or by inoculation withG. versiforme. Inoculation increased shoot dry weights and grain yields by 12% and 25% respectively, as compared with the 33% and 60% increases respectively produced by P-treated plants.