Effect of relative humidity on the airborne survival of rotavirus SA11.

Rotavirus SA11, suspended in tryptose phosphate broth with 2.5 mg of rhodamine B per ml, was aerosolized (Collison nebulizer) into a rotating drum, and the aerosols were held at 20 +/- 1 degree C with the desired relative humidity (RH). An all-glass impinger with tryptose phosphate broth was used to collect 1-min (5.6-liter) samples of air from the drum. The virus was found to survive best at medium (50 +/- 5%) RH, where its half-life was nearly 40 h. The half-life of the virus at the low (25 +/- 5%) RH level was about 9 h. Even at 72 h of aerosol age, 45 and 21% of the infectious virus remained detectable in the air at the medium and low RH levels, respectively. The high (80 +/- 5%) RH level was found to be the least favorable to the survival of the virus, since 50% of the infectious virus became undetectable within 2 h of aerosolization. In a separate experiment at the midrange RH, 3% of the infectious virus was detectable in the drum air after 223 h (9 days) of aerosol age. Rotaviruses could, therefore, survive in air for prolonged periods, thus making air a possible vehicle for their dissemination.     

Tsc2 Is a Molecular Checkpoint Controlling Osteoblast Development and Glucose Homeostasis

Insulin signaling in osteoblasts regulates global energy balance by stimulating the production of osteocalcin, a bone-derived protein that promotes insulin production and action. To identify the signaling pathways in osteoblasts that mediate insulin''s effects on bone and energy metabolism, we examined the function of the tuberous sclerosis 2 (Tsc2) protein, a key target important in coordinating nutrient signaling. Here, we show that loss of Tsc2 in osteoblasts constitutively activates mTOR and destabilizes Irs1, causing osteoblasts to differentiate poorly and become resistant to insulin. Young Tsc2 mutant mice demonstrate hypoglycemia with increased levels of insulin and undercarboxylated osteocalcin. However, with age, Tsc2 mutants develop metabolic features similar to mice lacking the insulin receptor in the osteoblast, including peripheral adiposity, hyperglycemia, and decreased pancreatic β cell mass. These metabolic abnormalities appear to result from chronic elevations in undercarboxylated osteocalcin that lead to downregulation of the osteocalcin receptor and desensitization of the β cell to this hormone. Removal of a single mTOR allele from the Tsc2 mutant mice largely normalizes the bone and metabolic abnormalities. Together, these findings suggest that Tsc2 serves as a key checkpoint in the osteoblast that is required for proper insulin signaling and acts to ensure normal bone acquisition and energy homeostasis.     

Assessment of the influence of intrinsic environmental and geographical factors on the bacterial ecology of pit latrines

Improving the rate and extent of faecal decomposition in basic forms of sanitation such as pit latrines would benefit around 1.7 billion users worldwide, but to do so requires a major advance in our understanding of the biology of these systems. As a critical first step, bacterial diversity and composition was studied in 30 latrines in Tanzania and Vietnam using pyrosequencing of 16S rRNA genes, and correlated with a number of intrinsic environmental factors such as pH, temperature, organic matter content/composition and geographical factors. Clear differences were observed at the operational taxonomic unit, family and phylum level in terms of richness and community composition between latrines in Tanzania and Vietnam. The results also clearly show that environmental variables, particularly substrate type and availability, can exert a strong structuring influence on bacterial communities in latrines from both countries. The origins and significance of these environmental differences are discussed. This work describes the bacterial ecology of pit latrines in combination with inherent latrine characteristics at an unprecedented level of detail. As such, it provides useful baseline information for future studies that aim to understand the factors that affect decomposition rates in pit latrines.     

Sequencing and Utilization of the Gossypium Genomes

Revealing the genetic underpinnings of cotton productivity will require understanding both the prehistoric evolution of spinnable fibers, and the results of independent domestication processes in both the Old and New Worlds. Progress toward a reference sequence for the smallest Gossypium genome is a logical stepping-stone toward revealing diversity in the remaining seven genomes (A, B, C, E, F, G, K) that permitted Gossypium species to adapt to a wide range of ecosystems in warmer arid regions of the world, and toward identifying the emergent properties that account for the superior productivity and quality of tetraploid cottons. The greatest challenge facing the cotton community is not genome sequencing per se but the conversion of sequence to knowledge.     

The spermatheca of Melanoplus sanguinipes (Fabr.). I. Morphology,histology, and histochemistry

The spermatheca of Melanoplus sanguinipes consists of a preapical and an apical diverticulum, and a long, thin ductus seminalis. Histologically, the three components are identical. The wall of the spermatheca includes a basement membrane, secretory and epithelial cells, and a cuticular intima. Small, discrete bundles of muscle occur outside the basement membrane. In each secretory cell is a large central cavity which connects with a cuticular channel (efferent ductule) running through the epithelial cell to the spermathecal lumen. During sexual maturation, light- and dark-staining vesicles accumulate in the secretory cells and discharge their contents into the central cavity. Simultaneously, glycogen accumulates in the epithelial cells. Allatectomy of newly emerged females renders the secretory cells unable to produce material, an effect which can be reversed by topical application of synthetic juvenile hormone. The secretion contains protein and acidic mucopolysaccharide. After insemination the quantities of secretion in the lumen and of glycogen in the epithelial cells diminish in the preapical diverticulum where almost all sperm are stored. As the number of sperm declines, the secretion and glycogen are replenished.     

Comparing aflatoxin contamination in chilies from Punjab,Pakistan produced in summer and winter

A comparison was made of total aflatoxins (AFs) in 43 samples of chilies collected during winter and 42 in summer to determine the effect of season on contamination. The samples were analyzed by HPLC with fluorescence detection. The limits of detection and quantification for AFB₁ and AFG₁ were 0.05 μg/kg and 0.50 μg/kg, whilst for AFG₂ and AFB₂ they were 0.10 μg/kg and 0.60 μg/kg. In the winter samples, AFs were detected in 18 (72%) whole and 14 (60%) ground chilies, with concentration ranges 0.00-52.30 μg/kg and 0.00-74.60 μg/kg respectively. In the summer samples, 17 (64%) whole and 12 (76%) ground chilies were contaminated with AFs at concentrations 0.00-61.50 μg/kg and 0.00-95.90 μg/kg respectively. The percentage of samples greater than the European Union statutory limit for AFB₁ and total AF for whole chilies were 48 and 36%, compared with ground chili values of 50 and 45%, respectively, in the winter season. In the summer season, the samples greater than the European Union limit for AFB₁ and total AF in whole chilies were 52 and 38%, compared with values of 54 and 49% in ground chilies respectively. AF contamination was found to be higher in summer chili samples and hence winter chilies may provide a better quality product with respect to AF contamination. The ability to undertake this analysis in Pakistan will enhance greatly the ability to improve chili production in that country, as described herein.     

Brn-4 transcription factor expression targeted to the early developing mouse pancreas induces ectopic glucagon gene expression in insulin-producing beta cells

The endocrine pancreas is comprised of beta and alpha cells producing the glucostatic hormones insulin and glucagon, respectively, and arises during development by the differentiation of stem/progenitor cells in the foregut programmed by the beta cell lineage-specific homeodomain protein Idx-1. Brain-4 (Brn-4) is expressed in the pancreatic anlaga of the mouse foregut at e10 in the alpha cells and transactivates glucagon gene expression. We expressed Brn-4 in pancreatic precursors or beta cell lineage in transgenic mice by placing it under either Idx-1 or insulin promoter (rat insulin II promoter) control, respectively. Idx-1 expression occurs at developmental day e8.5, and insulin expression occurs at e9.5, respectively. Misexpression of Brn-4 by the Idx-1 promoter results in ectopic expression of the proglucagon gene in insulin-expressing pancreatic beta cells, whereas misexpression by rat insulin II promoter did not. The early developmental expression of Brn-4 appears to be a dominant regulator of the glucagon expressing alpha cell lineage, even in the context of the beta cell lineage.     

Differences in the BAL proteome after <Emphasis Type="Italic">Klebsiella pneumoniae</Emphasis> infection in wild type and SP-A-/- mice

Background  

Surfactant protein-A (SP-A) has been shown to play a variety of roles related to lung host defense function. Mice lacking SP-A are more susceptible to infection than wild type C57BL/6 mice. We studied bronchoalveolar lavage (BAL) protein expression in wild type and SP-A-/- mice infected with Klebsiella pneumoniae by 2D-DIGE.     

Aflatoxin concentrations in chilies vary depending on variety

Aflatoxin (AF) contamination was determined in 40 chili samples, representing 3 varieties from Punjab, Pakistan, by HPLC with fluorescence detection. Total AF were determined in varieties Longi (n = 15), Wonder hot (n = 12), and Skyline 1 (n = 13), and the concentrations were high in some samples. AF were detected in 9 (60%), 8 (67%), and 7 (54%) of Longi, Wonder hot, and Skyline 1 samples, respectively; concentration ranged from 4.7 to 34.6, 1.0 to 14.3, and 7.8 to 15.6 μg/kg, respectively. The percentage of samples greater than the European Union statutory limit for AFB₁ and total AF in spices were 53% and 53%, 53% and 8%, and 53% and 38% for Longi, Wonder hot, and Skyline 1, respectively. Significant differences at α < 0.05 between mean concentration of AF in Longi (15.9 ± 0.6 μg/kg) and Wonder hot (5.8 ± 0.3 μg/kg) were determined. In conclusion, choosing the variety demonstrating the lowest AF concentration from various chili samples will assist in improving product quality. This preferred variety is Wonder Hot as described herein.