Nosocomial Vaccinia Infection

Although hospital-associated spread of vaccinia has been reported in the past, there have been no recent reports. This paper describes hospital-associated spread of vaccinia virus infection, supplies data on the environmental survival of vaccinia virus and offers recommendations for the management of patients with vaccinia that may minimize the hazard of infection in other high-risk patients.     

First identification of an amber nonsense mutation in Schizosaccharomyces pombe: major differences in the efficiency of homologous versus heterologous yeast suppressor tRNA genes

Summary In Saccharomyces cerevisiae ochre and opal, as well as amber mutations are known, whereas in the fission yeast Schizosaccharomyces pombe no amber alleles have been described. We have characterized trp1-566, an amber allele in the trp1 locus of S. pombe. The identification of trp1-566 as an amber allele is based on the following results: (a) The nonsense allele can be converted to an ochre allele by nitrosoguanidine mutagenesis. (b) trp1-566 is suppressed by a bona fide S. pombe amber suppressor tRNA, supSI. The supSI gene was obtained by primer-directed in vitro mutagenesis of a tRNASer from S. pombe. Unexpectedly, an S. cerevisiae amber suppressor tRNASer, supR21, transformed into S. pombe, failed to suppress trp1-566. Northern analysis of S. pombe transformants, containing supRL1 or S. cerevisiae tRNA^Leu or tRNA^Tyr genes reveals that these genes are not transcribed in the fission yeast. As an additional tool for the analysis of nonsense mutations in S. pombe, we obtained by nitrosoguanidine mutagenesis two unlinked amber suppressor alleles, sup13 and sup14, which act on trp1-566.     

The parathyroid gland of the woodchuck (Marmota monax): a study of seasonal variations in the chief cells

The ultrastructure of the parathyroid chief cell in the woodchuck, Marmota monax, was studied during the four seasons of the year. Spring chief cells have stacks of granular endoplasmic reticulum, prominent multiple Golgi zones and many clumped mitochondria. Summer cells resemble those seen in the spring but the mitochondria are associated with stacks of granular endoplasmic reticulum. Multiple areas of stacked granular endoplasmic reticulum characterize the fall chief cells. Their Golgi zones are large and are associated with many dense core secretory granules. Lipoid vacuoles are frequently noted. Winter chief cells have secretory granules and phagolysosomes (dense bodies). Some of these cells contain stacked arrays of granular endoplasmic reticulum associated with mitochondria, others have only short segments. The above morphological findings are discussed in relation to those in other hibernators, the parafollicular (C) cell, and to the cyclic seasonal activities of the woodchuck.     

Global gene expression profiling in Escherichia coli K12: effects of oxygen availability and ArcA

The ArcAB two-component system of Escherichia coli regulates the aerobic/anaerobic expression of genes that encode respiratory proteins whose synthesis is coordinated during aerobic/anaerobic cell growth. A genomic study of E. coli was undertaken to identify other potential targets of oxygen and ArcA regulation. A group of 175 genes generated from this study and our previous study on oxygen regulation (Salmon, K., Hung, S. P., Mekjian, K., Baldi, P., Hatfield, G. W., and Gunsalus, R. P. (2003) J. Biol. Chem. 278, 29837-29855), called our gold standard gene set, have p values <0.00013 and a posterior probability of differential expression value of 0.99. These 175 genes clustered into eight expression patterns and represent genes involved in a large number of cell processes, including small molecule biosynthesis, macromolecular synthesis, and aerobic/anaerobic respiration and fermentation. In addition, 119 of these 175 genes were also identified in our previous study of the fnr allele. A MEME/weight matrix method was used to identify a new putative ArcA-binding site for all genes of the E. coli genome. 16 new sites were identified upstream of genes in our gold standard set. The strict statistical analyses that we have performed on our data allow us to predict that 1139 genes in the E. coli genome are regulated either directly or indirectly by the ArcA protein with a 99% confidence level.     

Determinants of exclusive breastfeeding in rural South India

Background

While breastfeeding rates have improved globally, disparities in breastfeeding practices persist particularly in rural and low resource settings. In India, only 56% of Indian mothers practice exclusive breastfeeding (EBF) for the recommended six months. As India leads the world in the number of preterm births, under 5 years of age malnutrition and neonatal mortality, understanding the factors associated with EBF can help improve the nutritional status for millions of infants. We assessed the factors associated with EBF in rural Mysore, India.

Methods

This cross-sectional analysis was nested within a cohort study assessing the feasibility and uptake of mobile prenatal care and HIV counseling and testing intervention in Mysore District. Multivariable logistic regression was used to identify the factors associated with EBF for infants between birth and six months. Exclusive breastfeeding was defined as breastfeeding with no other liquids or breastfeeding substitutes given to infants exceptfor medicine or oral rehydration solution, between birth and 6 months and was assessed at six months postpartum.

Results

We surveyed mothers who delivered in rural Mysore taluk between 2008 and March 2011. A total of 1292 mothers participated in the study. The overall breastfeeding rate at six months postpartum was 74.9% and the EBF rate was 48.5%. Factors associated with EBF included higher maternal age (Adjusted Odds Ratio[aOR] 1.04; 95% Confidence Interval [CI] 1.00, 1.09), lower maternal education (aOR1.56, 95% CI 1.10, 2.21), and 7–10 antenatal visits (aOR 1.57; 95% CI 1.09, 2.27). The most common reason for non-exclusive breastfeeding was the mother’s feeling that she did not have enough milk (23.7%). Infants that were not exclusively breastfed were most commonly fed formula/animal milk (42.6%) or castor oil/ghee (18.4%).

Conclusions

Less than half of the mothers in our sample reported exclusive breastfeeding in a rural region of Karnataka, India in the first six months, a rate lower than national and state level rates. Future interventions should evaluate whether antenatal education can improve breastfeeding outcomes. The only modifiable factor was number of antenatal visits. Breastfeeding education should be emphasized at every antenatal visit so that even mothers with fewer than 7–10 antenatal visits can learn the best techniques and benefits of breastfeeding.

     

Protein Synthesis in the Developing Neocortex at Near-Atomic Resolution Reveals Ebp1-Mediated Neuronal Proteostasis at the 60S Tunnel Exit

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Social evolution in the shadow of asymmetrical relatedness

The persistence of altruism and spite remains an enduring problem of social evolution. It is well known that selection for these actions depends on the structure of the population—that is, on actors'' genetic relationships to recipients and to the ‘neighbourhood’ upon which the effects of their actions redound. Less appreciated, however, is that population structure can cause genetic asymmetries between partners whereby the relatedness (defined relative to the neighbourhood) of an individual i to a partner j will differ from the relatedness of j to i. Here, we introduce a widespread mechanism of kin recognition to a model of dispersal in subdivided populations. In so doing, we uncover three remarkable consequences of asymmetrical relatedness. First, altruism directed at phenotypically similar partners evolves more easily among migrant than native actors. Second, spite directed at dissimilar partners evolves more easily among native than migrant actors. Third, unlike migrants, natives can evolve to pay costs that far outstrip those they spitefully impose on others. We find that the frequency of natives relative to migrants amplifies the asymmetries between them. Taken together, our results reveal differentiated patterns of ‘phenocentrism’ that readily arise from asymmetries of relatedness.