Genetic diversity ofBradyrhizobium japonicum within soybean growing regions of the north-eastern Great Plains of North America as determined by REP-PCR and ERIC-PCR profiling

While soybean (Glycine max [L.] Merr.) has been grown for several decades in several northern states in the United States, the introduction of early maturing cultivars of soybean in western Canada in the late 1990’s has resulted in a exponential increase in soybean production in the region. Soybean grows in a symbiotic association withBradyrhizobium japonicum [Kirchner] Jordan, which carries out biological nitrogen fixation within the plant roots. Previous studies have shown that rhizobia introduced from commercial inoculants tend to evolve quickly in soil. In this study, we examined the genetic diversity of 105B. japonicum isolates from the soybean growing areas of the north-eastern Great Plains of North America by genomic fingerprinting techniques — REP-PCR and ERIC-PCR profiling. High genetic diversity was detected among theB. japonicum isolates sampled across various sites in North Dakota, South Dakota and Minnesota in the United States, and southern Manitoba in Canada. Analysis of the genetic diversity by the unweighted pair group method with an arithmetic mean algorithm(UPGMA) indicated an interesting segregation of isolates between US and Canadian sites. Results of this study also suggest a relatively rapid rate of genetic change within theB. japonicum populations and some evidence that soil texture may influence genetic diversity of the bacterium in the region.     

Daily variation in body core temperature using radio-telemetry in aluminium industry shift-workers

The aim of this study was to investigate the diurnal variation in core temperature in aluminium shift-workers exposed to hot ambient conditions. Core temperature was continuously recorded via an ingestible radio-telemetry thermistor in 29 shift-workers. Data from the morning, afternoon and night shifts were aggregated for each participant to obtain 24-h recordings during work duties. Complete data were obtained from 10 participants. Results showed that body core temperatures recorded in the afternoon (from 12:00 h to 20:00 h) were significantly higher (P<0.05) than in the late evening, night and early morning (from 21:00 h to 08:00 h). In addition, core temperature displayed a circadian variation with a mesor of 37.45 (±0.19) °C, an amplitude of 0.23 (±0.12) °C and an acrophase at 16:36 h (±3:37 h). The peak values of core temperature recorded at each hour of the day on the work site followed the same pattern with an acrophase in the early afternoon. In summary, our data showed that shift-workers present higher core temperatures in the afternoon than in the morning or during the night. In addition, it was not the work duration but the hour-of-day that triggered the variation in core temperature. This result partly explains previous observations that workers under heat stress have a higher probability of heat illness during daytime shifts than during the night shift, and suggests that special care should be given to the afternoon shift and to the end of the morning shift.     

Thermal Stress Impacts on Reproductive Development and Grain Yield in Grain Legumes

Temperature stress (cold, heat) during reproductive development is one of the serious constraints to the productivity of grain legumes as their cultivation is expanding to warmer environments and temperature variability is increasing due to climate change. Grain legumes exposed to temperature below 10-15°C or above 30°C show flower abortion, pollen and ovule infertility, impaired fertilization, and reduced seed filling, leading to substantial reduction in grain yield. For managing these effects of temperature extremes, it is important to improve the resistance of grain legumes by using improved breeding and genetic engineering tools. In this review article, the impact of both high and low temperature stress on different phases of the reproductive stage, from meiosis to grain filling, and the sensitivity of different reproductive organs to temperature extremes are discussed. The review also covers the management options to improve resistance to temperature stress in grain legumes. Furthermore, innovative breeding, genetic and molecular strategies in grain legumes against temperature stress are also discussed.     

A Model for diffusion controlled bioavailability of crude oil components

Crude oil is a complex mixture ofseveral different structural classes of compoundsincluding alkanes, aromatics, heterocyclic polarcompounds, and asphaltenes. The rate and extent ofmicrobial degradation of crude oil depends on theinteraction between the physical and biochemicalproperties of the biodegradable compounds and theirinteractions with the non-biodegradable fraction. Inthis study we have systematically altered theconcentration of non-biodegradable material in thecrude oil and analyzed its impact on transport of thebiodegradable components of crude oil to themicroorganisms. We have also developed a mathematicalmodel that explains and accounts for the dependence ofbiodegradation of crude oil through a putativebioavailability parameter. Experimental resultsindicate that as the asphaltene concentration in oilincreases, the maximum oxygen uptake in respirometersdecreases. The mathematically fitted bioavailabilityparameter of degradable components of oil alsodecreases as the asphaltene concentration increases.     

Effects of artificial feeding on aggressive behaviour of rhesus monkeys in India

Artificial feeding of rhesus monkeys (Macaca mulatta), which provides the major food source for most rhesus groups in rural and urban habitats, is common practice in India. Such feeding results in significant increases in aggressive competition within the monkey groups: during feeding periods the frequencies of aggressive threats, chases, and attacks increased two to six times above those of non-feeding periods in each of eight different groups. Fighting behaviour did not increase in most groups studied, but did show a rise in one large urban group in Calcutta. The implications of these results for the management of primate breeding colonies are discussed.     

Disappearance of [1alpha-3H]-chlormadinone acetate in the plasma and red cells of rhesus monkey.

The half-life and metabolic clearance rate of chlormadinone acetate in 4 rhesus monkeys was computed after iv injection. Chlormadinone was analyzed as total, free, and conjugated radioactivity, and as recrystallized chlormadinone acetate. 55.0 mc Ci, 222 mc Ci/mg was injected iv in 5 ml ethanolic saline. There was an initial rapid disappearance, half-life 68 minutes, and a slower disappearance, half-life 35.1 hours. These half-lives are much longer than those of estradiol and progesterone, but are shorter in monkeys than in women. The metabolic clearance rate of chlormadinone acetate was 102.6 liters/day. The half-life in red cells of 1 monkey was similar to those seen in plasma, but the amount of chlormadinone acetate was much less.