Investigations into rhizosphere microflora

Summary Effect of light and dark treatments on rhizosphere and rhizoplane microflora of two crops,viz Triticum aestivum. Linn. andHordeum vulgare Linn. has been investigated. Higher microbial population was recorded from the rhizosphere of plants exposed to continuous light while continuous dark set harboured lesser microflora. The microflora in 12 hours alternate light and dark set exhibited an intermediate condition. Amino acids (both qualitatively and quantitatively) in root extracts were the least in continuous dark and the maximum in continuous light set. The variation in root leakage, physiological and morphological condition of the plants was thought to be the cause for change in microbial activity. A part of the Ph. D. thesis approved by University of Gorakhpur, Gorakhpur, India (1969).     

Ultra-violet induced mutations to growth factor requirement and penicillin resistance in a blue-green alga

Summary After exposures to UV, two mutant strains of Phormidium mucicola were isolated which are stable and inheritable:1. Strain 5/5 mL-1 is a photoheterotrophic mutant requiring addition of an organic growth factor to the basal medium which appears fulfilled by either casein hydrolysate, glucose, acetate or vitamin mixture and fails to grow heterotrophically.2. mr/p. This strain shows resistance upto 10.24 g/ml of penicillin whereas the parent does not survive beyond a penicillin dose of 0.1 g/ml.     

Identification of nuclear proteins that specifically interact with adeno-associated virus type 2 inverted terminal repeat hairpin DNA.

A palindromic hairpin duplex containing the inverted terminal repeat sequence of adeno-associated virus type 2 (AAV) DNA was used as a substrate in gel retardation assays to detect putative proteins that specifically interact with the AAV hairpin DNA structures. Nuclear proteins were detected in extracts prepared from human KB cells coinfected with AAV and adenovirus type 2 that interacted with the hairpin duplex but not in nuclear extracts prepared from uninfected, AAV-infected, or adenovirus type 2-infected KB cells. The binding was specific for the hairpin duplex, since no binding occurred with a double-stranded DNA duplex with the identical nucleotide sequence. Furthermore, in competition experiments, the binding could be reduced with increasing concentrations of the hairpin duplex but not with the double-stranded duplex DNA with the identical nucleotide sequence. S1 nuclease assays revealed that the binding was sensitive to digestion with the enzyme, whereas the protein-bound hairpin duplex was resistant to digestion with S1 nuclease. The nucleotide sequence involved in the protein binding was localized within the inverted terminal repeat of the AAV genome by methylation interference assays. These nuclear proteins may be likely candidates for the pivotal enzyme nickase required for replication or resolution (or both) of single-stranded palindromic hairpin termini of the AAV genome.     

Fecundity of two hillstream fishes, Garra lamta (Ham.) and Garra gotyla gotyla (gray)

The fecundity of two hillstream fishes, Garra lamta and G. gotyla gotyla, is related to their total body length (L), total body weight (W), ovary length (X) and ovary weight (V). The relationships to L, W, X and V were all linear. The correlation coefficient values (r) showed that total body length and total body weight were the best indices in fecundity estimates in both fishes.     

Electron microscopic studies on liver 5-aminolaevulinate synthase

The structure of chick embryo liver 5-aminolaevulinate synthase has been examined by electron microscopic studies using negative staining. From the different projections of the enzyme particles observed in electron micrographs, a model for the enzyme molecule has been proposed. In this model, an enzyme molecule consists of two curved and identical subunits associated in opposite polarities. From the dimensions of an enzyme molecule subunit measured from electron micrographs, the relative molecular mass of each subunit is estimated to be 70 000.