The genomic sequence for Prader-Willi/Angelman syndromes' loci of human is apparently conserved in the great apes

Chromosomal changes through pericentric inversions play an important role in the origin of species. Certain pericentric inversions are too minute to be detected cytogenetically, thus hindering the complete reconstruction of hominoid phylogeny. The advent of the fluorescence in situ hybridization (FISH) technique has facilitated the identification of many chromosomal segments, even at the single gene level. Therefore the cosmid probe for Prader-Willi (PWS)/Angelman syndrome to the loci on human chromosome 15 [ql 1-12] is being used as a marker to highlight the complementary sequence in higher primates. We hybridized metaphase chromosomes of chimpanzee (PTR), gorilla (GGO), and orangutan (PPY) with this probe (Oncor) to characterize the chromosomal segments because the nature of these pericentric inversions remains relatively unknown. Our observations suggest that a pericentric inversion has occurred in chimpanzee chromosome (PTR 16) which corresponds to human chromosome 15 at PTR 16 band pl 112, while in gorilla (GGO 15) and orangutan (PPY 16) the bands q11-12 complemented to human chromosome 15 band q11-12. This approach has proven to be a better avenue to characterize the pericentric inversions which have apparently occurred during human evolution. Genetic divergence in the speciation process which occurs through chromosomal rearrangement needs to be reevaluated and further explored using newer techniques.Correspondence to: R.S. Verma     

Circadian variation in renal function of the obese rat.

The influence of food and water intake on renal function was assessed by comparisons between the hyperphagic Zucker obese rat and its lean littermate, which demonstrates nocturnal dominance in activity. Serum creatinine and cortisol levels, creatine kinase activities, creatinine and urine clearances, and sodium and potassium excretion rates were measured over a 24-hour period in both lean and obese rats (n = 24 each). Six rats in each group were studied every 8 h to permit characterization over a 12-hour light/dark cycle at 2-hour intervals. Urine and creatinine clearances were increased in lean rats during the dark phase coincident with onset of eating. Similarly, renal sodium and potassium excretion rates were markedly increased during the dark cycle, despite relatively constant serum potassium and sodium levels over the 24-hour period. In contrast, no circadian patterns in urine and creatinine clearances were found in the obese rat, which exhibits continuous feeding habits throughout the 24-hour period. Moreover, renal electrolyte excretion in the obese rat was modestly increased during the dark cycle, unlike the significant differences over time observed in lean rats. Serum creatinine levels were increased during the dark cycle in both rat groups. Creatine kinase activity, a measure of ambulatory activity, was constant in lean rats during the study period. Although creatine kinase activity was increased in obese rats during the dark cycle, no correlations with renal functional parameters were found. These results indicate that differences in food and water intake are significant determinants in diurnal cyclic changes in renal function.     

Inhibitory effects of orotate on precursor incorporation into nucleic acids.

The influence of orotic acid on the incorporation of precursors into nucleic acids was studied in mice and rats and in isolated cells. In vivo, orotate levels were modified by two diets which are known to increase the rate of pyrimidine nucleotide synthesis in rat liver. Of these diets, a 1% orotate diet had greater inhibitory effects than an arginine-deficient diet on the incorporation of [3H]orotate into RNA of mouse kidney than mouse liver. This contrasted with the situation in the rat where there was a greater effect in the liver than the kidney. The situation in the rat was more readily interpreted than in the mouse in terms of previously established effects of these diets on ribonucleotide pool sizes. However, studies using [3H]adenosine as a precursor for incorporation into RNA suggested that even in the mouse the effects of orotate were on pool sizes rather than an inhibitory effect on RNA synthesis. The incorporation of [3H]thymidine into DNA was inhibited by orotate to a similar degree in cultured HTC hepatoma cells and a line of rat liver epithelial cells. An effect on DNA synthesis rather than solely on pool sizes was suggested by the observation that the pool size of dTTP was not increased by 5 mM orotate under conditions in which there was a four-fold increase in the level of UTP in HTC cells. An inhibitory effect of orotate on DNA synthesis was further supported by an observation of decreased incorporation of [3H]deoxyadenosine into DNA and a lower rate of cellular proliferation.     

A simple technique for estimation ofDrechslera nodulosa (Berk. & Curt.) Subram. and Jain propagules in soil

Summary A baiting technique was developed to estimate the population ofDrechslera nodulosa (Berk. and Curt.) Subram. and Jain in soil by using susceptible ragi (Eleusine coracana Gaertn.) culms. The number of lesions developed on baited culms were reduced with the reduction in concentration ofD. nodulosa propagules in both sterilized and unsterilized soils. Based on this a standard correlation (concentrationvs infection probability) was established which was found to be quite efficient method to estimate the population in soil and to bait even when the inoculum level was 4 propagules per g of soil.     

Intersexual variation in the foraging ecology of sexually monochromatic Western Wood‐Pewees

ABSTRACT Investigators generally pool observations of males and females in studies of the foraging behavior of sexually monochromatic songbirds. However, such pooling can obscure possible intersexual differences. We compared the foraging behavior of male and female Western Wood‐Pewees (Contopus sordidulus), a sexually monochromatic species, in the Sierra Nevada Mountains of California during the breeding seasons of 2007 and 2008. We recorded 143 foraging observations (male N= 74, female N= 69). Overall, mean foraging rates of females (2.8 attacks/min) were higher (P < 0.001) than those of males (1.1 attacks/min). In addition, female foraging rates were significantly higher during incubation than during the nest building, nestling, and fledgling periods. When foraging, males perched higher above ground than females (means = 17.1 and 6.7 m, respectively). Differences between male and female Western Wood‐Pewees in foraging rates and perch heights suggest that males may spend more time on vigilance while females focus on foraging quickly during incubation and when feeding nestlings. Because metrics such as foraging attack rates are sometimes used as indicators of habitat quality and we found that rates can differ between the sexes and among nesting stages, investigators should consider the possibility of such differences when assessing habitat quality, especially for sexually monochromatic species of birds.     

Effects of chemical and botanical insecticides used for locust control on Metarhizium anisopliae var. acridum conidia after short- to medium-term storage at 30°C

The short- to medium-term viability and growth of Metarhizium anisopliae var. acridum conidia were investigated when combined with six insecticides, at three different concentrations. All of the insecticides used in this study were suitable for immediate spraying with M. anisopliae var. acridum conidia except for fenitrothion. Fipronil, teflubenzuron, and fenitrothion formulations significantly reduced conidial viability over time. The 10% teflubenzuron treatment caused loss of viability relatively quickly with 9.9% germination after 28 days. Mycelial growth was affected by all the treatments except fenitrothion.     

Post‐fire development of faunal habitat depends on plant regeneration traits

The concept that vegetation structure (and faunal habitat) develops predictably with time since fire has been central to understanding the relationship between fire and fauna. However, because plants regenerate after fire in different ways (e.g. resprouting from above‐ground stems vs. underground lignotubers), use of simple categories based on time since fire might not adequately represent post‐fire habitat development in all ecosystems. We tested the hypothesis that the post‐fire development of faunal habitat structure differs between ecosystems, depending on fire regeneration traits of the dominant canopy trees. We measured 12 habitat components at sites in foothill forests (n = 38), heathy woodlands (n = 38) and mallee woodlands (n = 98) in Victoria, Australia, and used generalised additive models to predict changes in each variable with time since fire. A greater percentage of faunal habitat variables responded significantly to time since fire in mallee woodlands, where fires typically are stand‐replacing, than in foothill forests and heathy woodlands, where canopy tree stems generally persist through fire. In the ecosystem with the highest proportion of epicormic resprouters (foothill forests), only ground cover and understorey vegetation responded significantly to time since fire, compared with all but one variable in the ecosystem dominated by basal resprouters (mallee woodlands). These differences between ecosystems in the post‐fire development of key habitat components suggest there may also be fundamental differences in the role of fire in shaping the distribution of fauna. If so, this challenges the way in which many fire‐prone ecosystems currently are categorised and managed, especially the level of dependence on time since fire and other temporal surrogates such as age‐classes and successional states. Where time since fire is a poor surrogate for habitat structural development, additional complexity (e.g. fire severity, topography and prior land‐use history) could better capture processes that determine faunal occurrence in fire‐prone ecosystems.