Transglutaminase-mediated cross-linking of GerQ in the coats of Bacillus subtilis spores

The spores of Bacillus subtilis show remarkable resistance to many environmental stresses, due in part to the presence of an outer proteinaceous structure known as the spore coat. GerQ is a spore coat protein essential for the presence of CwlJ, an enzyme involved in the hydrolysis of the cortex during spore germination, in the spore coat. Here we show that GerQ is cross-linked into higher-molecular-mass forms due in large part to a transglutaminase. GerQ is the only substrate for this transglutaminase identified to date. In addition, we show that cross-linking of GerQ into high-molecular-mass forms occurs only very late in sporulation, after mother cell lysis. These findings, as well as studies of GerQ cross-linking in mutant strains where spore coat assembly is perturbed, lead us to suggest that coat proteins must assemble first and that their cross-linking follows as a final step in the spore coat formation pathway.     

Parathymosin affects the binding of linker histone H1 to nucleosomes and remodels chromatin structure

Linker histone H1 is the major factor that stabilizes higher order chromatin structure and modulates the action of chromatin-remodeling enzymes. We have previously shown that parathymosin, an acidic, nuclear protein binds to histone H1 in vitro and in vivo. Confocal laser scanning microscopy reveals a nuclear punctuate staining of the endogenous protein in interphase cells, which is excluded from dense heterochromatic regions. Using an in vitro chromatin reconstitution system under physiological conditions, we show here that parathymosin (ParaT) inhibits the binding of H1 to chromatin in a dose-dependent manner. Consistent with these findings, H1-containing chromatin assembled in the presence of ParaT has reduced nucleosome spacing. These observations suggest that interaction of the two proteins might result in a conformational change of H1. Fluorescence spectroscopy and circular dichroism-based measurements on mixtures of H1 and ParaT confirm this hypothesis. Human sperm nuclei challenged with ParaT become highly decondensed, whereas overexpression of green fluorescent protein- or FLAG-tagged protein in HeLa cells induces global chromatin decondensation and increases the accessibility of chromatin to micrococcal nuclease digestion. Our data suggest a role of parathymosin in the remodeling of higher order chromatin structure through modulation of H1 interaction with nucleosomes and point to its involvement in chromatin-dependent functions.     

A comparative volumetric analysis of the amygdaloid complex and basolateral division in the human and ape brain

The amygdaloid complex functions to facilitate effective appraisal of the social environment and is an essential component of the neural systems subserving social behavior. Despite its critical role in mediating social interaction, the amygdaloid complex has not attracted the same attention as the isocortex in most evolutionary analyses. We performed a comparative analysis of the amygdaloid complex in the hominoids to address the lack of comparative information available for this structure in the hominoid brain. We demarcated the amygdaloid complex and the three nuclei constituting its basolateral division, the lateral, basal, and accessory basal nuclei, in 12 histological series representing all six hominoid species. The volumes obtained for these areas were subjected to allometric analyses to determine whether any species deviated from expected values based on the other hominoids. Differences between groups were addressed using nonparametric comparisons of means. The human lateral nucleus was larger than predicted for an ape of human brain size and occupied the majority of the basolateral division, whereas the basal nucleus was the largest of the basolateral nuclei in all ape species. In orangutans the amygdala and basolateral division were smaller than in the African apes. While the gorilla had a smaller than predicted lateral nucleus, its basal and accessory basal nuclei were larger than predicted. These differences may reflect volumetric changes occurring in interconnected cortical areas, specifically the temporal lobe and orbitofrontal cortex, which also subserve social behavior and cognition, suggesting that this system may be acted upon in hominoid and hominid evolution.     

Berry fruits as a source of biologically active compounds: the case of Lonicera caerulea

Background: Lonicera caerulea L. (blueberry honeysuckle, Caprifoliaceae) is a traditional crop in northern Russia, China, and Japan. Its fruits are little known as edible berries in North America and Europe. This review deals with the botany and chemical composition of L. caerulea and the biological activity of its main constituents, focusing on the potential health benefits of the berries. Methods and Results: PubMed, Science Direct and ISI Web of Knowledge(SM) databases were used for this paper. Literature sources include the period 1935-2007. L. caerulea berries a are rich source of phenolic compounds such as phenolic acids as well as anthocyanins, proanthocyanidins and other flavonoids, which display potential health promoting effects. Chemopreventive, antimicrobial, anti-adherence and antioxidant benefits, among others are described for these compounds. Conclusions: The potential of L. caerulea berries to prevent chronic diseases such as diabetes mellitus, cardiovascular diseases and cancer seems to be related above all to their phenolic content.     

The crystal structure of annexin A8 is similar to that of annexin A3

Annexin A8 is a relatively infrequent and poorly studied member of this large family of calcium-binding and membrane-binding proteins. It is, however, associated with a specific disease, acute promyelocytic leukemia. We have solved its three-dimensional structure, which includes a moderately long and intact N terminus. The structure is closest to that of annexin A3 and highlights several important regions of inherent flexibility in the annexin molecule. The N terminus resembles that of annexin A3, as it lies along the concave surface of the molecule and inserts partially into the hydrophilic channel in its centre. Since both annexins A3 and A8 are expressed in promyelocytic cells during their differentiation, the similarity in their structures might suggest a functional relationship.     

Risk factors for cardiovascular diseases in physicians

The aim of the study was to determine the prevalence of risk factors for cardiovascular diseases among physicians at a teaching hospital. In total, 203 men and 167 women were included in the study. The participants filled in a questionnaire; their height, weight, blood pressure, serum cholesterol and glucose levels were added. 19.2 % males and 13.8 % females were smokers, hypertension was diagnosed in 10 % of males and in 6.6 % of females, 52.2 % males and 17.4 % females were overweight, 37 % males and 43.1 % females had hypercholesterolemia. The above findings suggest that Czech physicians have more favourable values of all the studied cardiovascular diseases risk factors than the general Czech population. However, Czech physicians smoke more than those in other countries and their level of cardiovascular diseases risk factors is unsatisfactory and calls for further intensive prevention. Preliminary outcomes of the study repeated after two years show no positive trends as well as physicians' low willingness to actively participate in lowering cardiovascular diseases risk factors.