Prevalence and Determinants of Adult Under-Nutrition in Botswana

Background

To estimate the prevalence and determinants of adult under-nutrition in Botswana.

Methods

A cross-sectional survey was conducted where a nationally representative sample of people aged 20 to 49 years was used for the analysis. The outcome measure of under-nutrition was measured as BMI<18.5 kg/m².

Results

Of the total sample, 19.5% of males and 10.1% of females were underweight (BMI<18.5 kg/m²). The wealth index showed that 30.9% of the adult population with low a BMI belongs to the poorest 20% of the households while only 9.6% comprised of the richest 20% of the households. Results from logistic regression analysis indicated that both adult men and women who had no education and belonged to the low socioeconomic group had a statistically significant association with low BMI. Among the female adult population, being young and not having watched TV at least once a week were significantly associated with low BMI. For the male adult population, being unmarried was significantly associated with low BMI.

Conclusions

Programme interventions aimed at improving the nutritional status of adults can use these findings to make appropriate policy, to establish baselines and study nutritional changes over time and its covariates.     

Directed evolution of enzymes and pathways for industrial biocatalysis

Directed evolution has become a powerful tool for developing enzyme and whole cell based biocatalysts. Significant recent advances include the creation of novel enzyme functions and the development of several new efficient directed evolution methods. The combination of directed evolution and rational design promises to accelerate the development of biocatalysts for applications in the pharmaceutical, chemical and food industries.     

Finding the right balance between resistance and sensitivity: a review of the cardiac manifestations of the syndrome of resistance to thyroid hormone and the implications for treatment

ObjectiveTo review cardiac manifestations in the syndrome of resistance to thyroid hormone (RTH) and to question the general recommendation that the thyroidstimulating hormone (TSH) value be the guide to thyroid hormone replacement.MethodsThe syndrome of RTH is caused by mutations in the carboxyterminal portion of the β isoform of the thyroid hormone receptor, resulting in variable clinical manifestations. It is generally recommended that the replacement of thyroid hormone in patients with RTH be guided by the serum TSH concentration. The variable responsiveness of tissues to thyroid hormone, however, makes it difficult to balance the correct replacement dose. We present a case that brings into question the conventional wisdom about the replacement dose of thyroid hormone in this scenario, and we review the pertinent literature.ResultsA 54- year-old man with RTH was treated with levothyroxine and increasing doses of liothyronine sodium as part of an evaluation of RTH. On day 10 of theprotocol, he developed atrial fibrillation despite a normal level of TSH (1.1 mIU/L). Administration of liothyronine was discontinued, and cardioversion was planned; however, the patient’s heart rhythm converted spontaneously to normal sinus rhythm.ConclusionReplacement of thyroid hormone in patients with RTH should include careful monitoring of thyrotoxic cardiac side effects in addition to consideration of normalization of the TSH level. (Endocr Pract. 2012;18:252- 255)     

Stability of Adult Emergence and Activity/Rest Rhythms in Fruit Flies Drosophila melanogaster under Semi-Natural Condition

Here we report the results of a study aimed at examining stability of adult emergence and activity/rest rhythms under semi-natural conditions (henceforth SN), in four large outbred fruit fly Drosophila melanogaster populations, selected for emergence in a narrow window of time under laboratory (henceforth LAB) light/dark (LD) cycles. When assessed under LAB, selected flies display enhanced stability in terms of higher amplitude, synchrony and accuracy in emergence and activity rhythms compared to controls. The present study was conducted to assess whether such differences in stability between selected and control populations, persist under SN where several gradually changing time-cues are present in their strongest form. The study revealed that under SN, emergence waveform of selected flies was modified, with even more enhanced peak and narrower gate-width compared to those observed in the LAB and compared to control populations in SN. Furthermore, flies from selected populations continued to exhibit enhanced synchrony and accuracy in their emergence and activity rhythms under SN compared to controls. Further analysis of zeitgeber effects revealed that enhanced stability in the rhythmicity of selected flies under SN was primarily due to increased sensitivity to light because emergence and activity rhythms of selected flies were as stable as controls under temperature cycles. These results thus suggest that stability of circadian rhythms in fruit flies D. melanogaster, which evolved as a consequence of selection for emergence in a narrow window of time under weak zeitgeber condition of LAB, persists robustly in the face of day-to-day variations in cycling environmental factors of nature.     

Role of anionic charges of osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium SL1344 in mice virulence

opgB gene of Salmonella enterica serovar Typhimurium was identified earlier in a genome-wide screen for mice virulence (Valentine et al. in Infect Immun 66:3378-3383, 1998). Although mutation in opgB resulted in avirulent Salmonella strain, how this gene contributes to pathogenesis remains unclear. Based on DNA homology, opgB is predicted to be responsible for adding phosphoglycerate residues to osmoregulated periplasmic glucans (OPGs) giving them anionic characteristics. In Escherichia coli, yet another gene, opgC, is also reported to contribute to anionic characteristics of OPGs by adding succinic acid residues. We constructed opgB, opgC, and opgBC double mutants of S. enterica serovar Typhimurium strain SL1344. As predicted opgBC mutant synthesized neutral OPGs that were devoid of any anionic substituents. However, opgB, opgC, and opgBC mutations had no significant impact on mice virulence as well as on competitive organ colonization. In low osmotic conditions, opgB, opgC, and opgBC mutants exhibited delay in growth initiation in the presence of sodium deoxycholate. Anionic substituents of OPGs from Salmonella although appear to be needed to overcome resistance of deoxycholate in hypoosmotic growth media, no evidence was found for their role in mice virulence.     

Peptidyl-prolyl isomerase Pin1 controls down-regulation of conventional protein kinase C isozymes

The down-regulation or cellular depletion of protein kinase C (PKC) attendant to prolonged activation by phorbol esters is a widely described property of this key family of signaling enzymes. However, neither the mechanism of down-regulation nor whether this mechanism occurs following stimulation by physiological agonists is known. Here we show that the peptidyl-prolyl isomerase Pin1 provides a timer for the lifetime of conventional PKC isozymes, converting the enzymes into a species that can be dephosphorylated and ubiquitinated following activation induced by either phorbol esters or natural agonists. The regulation by Pin1 requires both the catalytic activity of the isomerase and the presence of a Pro immediately following the phosphorylated Thr of the turn motif phosphorylation site, one of two C-terminal sites that is phosphorylated during the maturation of PKC isozymes. Furthermore, the second C-terminal phosphorylation site, the hydrophobic motif, docks Pin1 to PKC. Our data are consistent with a model in which Pin1 binds the hydrophobic motif of conventional PKC isozymes to catalyze the isomerization of the phospho-Thr-Pro peptide bond at the turn motif, thus converting these PKC isozymes into species that can be efficiently down-regulated following activation.     

Design principles underpinning the regulatory diversity of protein kinases

Protein phosphorylation in eukaryotes is carried out by a large and diverse family of protein kinases, which display remarkable diversity and complexity in their modes of regulation. The complex modes of regulation have evolved as a consequence of natural selection operating on protein kinase sequences for billions of years. Here we describe how quantitative comparisons of protein kinase sequences from diverse organisms, in particular prokaryotes, have contributed to our understanding of the structural organization and evolution of allosteric regulation in the protein kinase domain. An emerging view from these studies is that regulatory diversity and complexity in the protein kinase domain evolved in a 'modular' fashion through elaboration of an ancient core component, which existed before the emergence of eukaryotes. The core component provided the conformational flexibility required for ATP binding and phosphoryl transfer in prokaryotic kinases, but evolved into a highly regulatable domain in eukaryotes through the addition of exaggerated structural features that facilitated tight allosteric control. Family and group-specific features are built upon the core component in eukaryotes to provide additional layers of control. We propose that 'modularity' and 'conformational flexibility' are key evolvable traits of the protein kinase domain that contributed to its extensive regulatory diversity and complexity.