Rigid structural requirement of the 5' terminus of mRNA for translational activity.

Oxidation by sodium periodate of the ribose cis-diol of the 5′ terminal of liver mRNA to the corresponding dialdehyde virtually destroyed its template activity in the wheat germ translation system. The rigid structural requirement for the ribose cis-diol is indicated by the failure of reduction of the dialdehyde to the corresponding primary alcohols to restore the template activity of the mRNA. Sodium periodate alone inhibited the translational system at concentrations above 0.25 mM. Purification of the periodate oxidized mRNA by sucrose density gradient centrifugation or exclusion on Sephadex G-100 did not increase its template activity. Periodate oxidized mRNA was not inhibitory to translation of untreated mRNA.     

Effect of CO2 on the germination of conidiospores of Aspergillus niger

Summary The effect of different concentrations of CO₂ on the germination of conidiospores of Aspergillus niger A 5 has been studied using Pardee's buffer mixtures which maintain constant CO₂ tensions. The beneficial effect of CO₂ on germination is maximum at 0.5% CO₂ concentration, when 70–90% of the spores germinate within 6 hours, whereas in controls with air containing 0.03% CO₂ there is only 15–20% germination at 6 hours. At higher CO₂ concentrations this beneficial effect of CO₂ on germination diminishes and at 3% there is a complete inhibition of spore germination.The spore density and the ph of the medium have a noticeable effect on germination rates in presence of 0.5% CO₂. The germination rates decrease at spore densities higher than 5 · 10⁵/ml and at a ph of 6.8.Communication No. 431.     

Effect of acidicpH on the protein carmin from safflower seed (Carthamus tinctorius)

The effect of a decrease inpH on the structural integrity of carmin has been monitored by a variety of biophysical techniques. The protein undergoes initial dissociation up topH 3.5–4.0 without any significant denaturation. Below thispH the process of dissociation and denaturation appears to be simultaneous. Further, in thepH range of 2.5–1.6 the protein reassociates to probably a different polymer resulting from possibly, an entropically driven hydrophobic interaction. The process of dissociation appears to be reversible to a large extent. The process of denaturation appears to be governed by the kinetic path that the denatured protein molecule follows either by a sudden decrease inpH or through a gradual decrease inpH. These results are interpreted while keeping in view the oligomeric and globular structure of carmin at neutralpH. The results would help in understanding of structure-function relationship of the protein and its role in hydrogen ion bindingin vivo.     

Dicarboxylic aminoaciduria associated with mental retardation

Summary Five hundred mentally retarded children (of both sexes and under 15 years of age) referred to our institute were screened for aminoacid disorders. One case of dicarboxylic aminoaciduria was found in a girl.     

An inducible acetate transport system in Neurospora crassa conidia

Neurospora crassa conidia possess an active transport system for the uptake of acetate. This system was characterized as: (a) energy dependent; (b) taking place against a concentration gradient; (c) saturating at higher substrate concentrations and (d) competitively inhibited by propionate.Activity of the acetate transport system can be further enhanced by preincubating conidia in 1 mM acetate medium for 180 min (the inducible transport system). The conidial system and the inducible system have similar properties. The development of the inducible transport was dependent on RNA and protein synthesis. A genetic control of this system was further confirmed by isolating a mutant (acp⁻ⁱ acetate permease, inducible) that fails to develop the inducible transport system.