SIMPLE AND RAPID METHOD FOR SCREENING ANTIMICROBIAL ACTIVITIES OF BIFIDOBACTERIUM SPECIES OF HUMAN ISOLATES

The objective of this research was to develop a rapid procedure for the screening antimicrobial activities of Bifidobacterium species of human isolates. A bifidobacteria selective medium BIM-25 agar was modified by adding of 0.5 g/L cysteine-hydrochloride, 1.5 g/L lithium chloride, 1.0 g/L beef extract, and 5 mL/L Tween 20. This medium was inoculated (45C) with diluted fecal material from 5 subjects and overlaid into 0.1% Tween 20 BHI agar plates. Plates were incubated in anaerobic chamber at 37C for 48 h. Plates were then inverted to allow the two layers of agar to fall into the petri lid. BHI soft agar (0.45%) containing Micrococcus luteus (as indicator) was overlaid onto the other layers in the petri dish. Plates were incubated at 37C overnight and zone of growth inhibition was observed. This method is simple and rapid whereas the original method for screening of antimicrobial activities of bifidobacteria is a more time consuming and cumbersome procedure.     

Effect of red, far-red radiations on germination of cotton seed

Seeds of two cultivars, H-14 and J-34 of Gossypium hirsutumL. soaked in the dark for durations of 8, 12 and 16 hr wereexposed to red and far-red radiations alone and in differentsuccessions. While cv. J-34 was unresponsive to all light treatments,seed germinaiton in cv.H-14 was promoted by darkness and byexposure to far-red radiation and was inhibited by red andwhitelight.Seed germination depended upon what treatment was given at theend. The effect ofred light was reversed by far-red and viceversa. Although instances of light inhibition of seed germinationare known, the authors are not aware of any clear cut instancein the literature on far-red promotion of seed germination (Received November 4, 1970; )     

Effect of age on reproductive attributes of an aphidophagous ladybird, Cheilomenes sexmaculata

The effect of both male and female age was investigated on certain reproductive attributes, viz. mating incidence, mating duration, fecundity, percent egg viability, ratio of reproductive and non‐reproductive periods and reproductive rate, of an aphidophagous ladybird, Cheilomenes sexmaculata (Fabricius). Females started mating at the age of 8 hours post‐emergence (PE) and males at the age of 2 days PE. Mating in the laboratory was a male‐dominated phenomenon. The mating duration and reproductive rate of 10‐day‐old females when mated with males of varying ages increased up to the male age of 60 days, and thereafter decreased, whereas, fecundity, egg viability and ratio of reproductive and non‐reproductive periods increased up to the male age of 50 days, and thereafter declined. However, when females of varying ages were mated with 10‐day‐old males, fecundity and reproductive rate increased up to 40 days of female age, respectively, then decreased. The ratio of reproductive and non‐reproductive periods increased with increasing age of females. Mating age for optimal reproductive output was 10J50‐day‐old males and NE to 40‐day‐old females. Reproductive cessation in males was recorded after 50 days PE, whereas in females at the age of 40 days PE. Higher mating durations lead to elevated reproductive rates. Delay in the reproductive phase was positively correlated with longevity. The results of this study may aid mass multiplication of this ladybird by identifying and promoting usage of adults of optimal age. Our results also enhance our understanding of the effect of age on reproductive attributes in ladybirds.     

Structure and Function of Oak Forests in Central Himalaya. II. Nutrient Dynamics

This paper elucidates nutrient dynamics in oak forests previouslyinvestigated for dry matter dynamics. The nutrient concentrationsin different life forms were of the order: herb > shrub >tree, whereas the standing state of nutrients were of the order:tree > shrub > herb. Soil, litter and vegetation, respectively,accounted for 32·4–98·0 %; 0·3–3·5%, and 10·2–66·6 % of the total nutrientsin the system. Considerable reductions (8·5–41·7%)in concentrations of nutrients in leaves occurred during senescence.The uptake of nutrients by vegetation, and also by differentcomponents with and without adjustment for internal recycling,has been calculated separately. Annual transfer of litter (above+ below ground) to the soil by vegetation was 115·9–187N, 7·5–15·6 P, 122·7–195·1Ca, 36·1–48·8 K and 2·88–5·16Na kg ha^–1 yr^–1. Turnover rate and turnover timefor different nutrients ranged between 0·66–0·84yr^–1 and 1·19–1·56 yr^–1, respectively.Compartment models for nutrient dynamics have been developedto represent the distribution of nutrient contents and net annualfluxes within the system. Quercus leucotrichophora forest, Q.floribunda forest, Q. lanuginosa forest, Nutrient concentration, standing state, uptake, internal cycling, turnover