Ginkgo biloba Expresses Calreticulin,the Major Calcium-Binding Reticuloplasmin in Eukaryotic Cells

Calreticulin, the main Ca²⁺ binding protein in the endoplasmic reticulum of eukaryotic cells, was characterized in Ginkgo biloba L. pollen and seeds. Electrophoretic analysis of the partly purified extracts showed the presence of two protein bands of 57 and 50kDa apparent molecular masses, which strongly cross-reacted with antibodies against plant calreticulins. Amino acid sequence comparison with other plant and animal calreticulins revealed a much higher similarity of the N-terminus of Ginkgo calreticulins with the homologue from angiosperms rather than with that from mammals. The finding of calreticulin in Ginkgo is indicative of the conservation also in gymnosperms of Ca²⁺ homeostatic mechanisms, which seem to rely on the same molecular components as all eukaryotic cells.     

Personal Networks and Mortality Risk in Older Adults: A Twenty-Year Longitudinal Study

Background

Research on aging has consistently demonstrated an increased chance of survival for older adults who are integrated into rich networks of social relationships. Theoretical explanations state that personal networks offer indirect psychosocial and direct physiological pathways. We investigate whether effects on and pathways to mortality risk differ between functional and structural characteristics of the personal network. The objective is to inquire which personal network characteristics are the best predictors of mortality risk after adjustment for mental, cognitive and physical health.

Methods and Findings

Empirical tests were carried out by combining official register information on mortality with data from the Longitudinal Aging Study Amsterdam (LASA). The sample included 2,911 Dutch respondents aged 54 to 85 at baseline in 1992 and six follow-ups covering a time span of twenty years. Four functional characteristics (emotional and social loneliness, emotional and instrumental support) and four structural characteristics (living arrangement, contact frequency, number of contacts, number of social roles) of the personal network as well as mental, cognitive and physical health were assessed at all LASA follow-ups. Statistical analyses comprised of Cox proportional hazard regression models. Findings suggest differential effects of personal network characteristics on survival, with only small gender differences. Mortality risk was initially reduced by functional characteristics, but disappeared after full adjustment for the various health variables. Mortality risk was lowest for older adults embedded in large (HR = 0.986, 95% CI 0.979—0.994) and diverse networks (HR = 0.948, 95% CI 0.917—0.981), and this effect continued to show in the fully adjusted models.

Conclusions

Functional characteristics (i.e. emotional and social loneliness) are indirectly associated with a reduction in mortality risk, while structural characteristics (i.e. number of contacts and number of social roles) have direct protective effects. More research is needed to understand the causal mechanisms underlying these relations.     

The Microbiota and Abundance of the Class 1 Integron-Integrase Gene in Tropical Sewage Treatment Plant Influent and Activated Sludge

Bacteria are assumed to efficiently remove organic pollutants from sewage in sewage treatment plants, where antibiotic-resistance genes can move between species via mobile genetic elements known as integrons. Nevertheless, few studies have addressed bacterial diversity and class 1 integron abundance in tropical sewage. Here, we describe the extant microbiota, using V6 tag sequencing, and quantify the class 1 integron-integrase gene (intI1) in raw sewage (RS) and activated sludge (AS). The analysis of 1,174,486 quality-filtered reads obtained from RS and AS samples revealed complex and distinct bacterial diversity in these samples. The RS sample, with 3,074 operational taxonomic units, exhibited the highest alpha-diversity indices. Among the 25 phyla, Proteobacteria, Bacteroidetes and Firmicutes represented 85% (AS) and 92% (RS) of all reads. Increased relative abundance of Micrococcales, Myxococcales, and Sphingobacteriales and reduced pathogen abundance were noted in AS. At the genus level, differences were observed for the dominant genera Simplicispira and Diaphorobacter (AS) as well as for Enhydrobacter (RS). The activated sludge process decreased (55%) the amount of bacteria harboring the intI1 gene in the RS sample. Altogether, our results emphasize the importance of biological treatment for diminishing pathogenic bacteria and those bearing the intI1 gene that arrive at a sewage treatment plant.     

Human conjunctival epithelial precursor cells and their progeny in 3D organotypic culture

We report on an in vitro organ culture method to investigate human conjunctival epithelial basal precursor cells and their progeny within a more natural three-dimensional microenvironment. Conjunctival fragments were cultured on gelatin sponges in medium with 10% FBS. The conjunctival phenotype of the epithelium was confirmed by the expression and distribution of a panel of markers (p63, CK-13/CK-10, CK-19, Ki-67, PAS for goblet cells, CD45 for infiltrating interlamellar leukocytes and nestin for mesenchymal and ocular epithelial precursor cells). After 7 days, the epithelium had exfoliated its superficial layers (mostly CK-19( )positive cells and all goblets), maintaining only 1-2 layers of basal/parabasal cells, p63, CK-13/CK-10 and nestin positive cells, firmly attached to the specimen. After 14 days, a new multilayered epithelium was formed, consisting of p63, CK-13/CK-10, nestin positive cells and in the high-zone CK-19 positive cells with new goblets. Additionally, we found interlamellar leukocytes which had probably migrated from capillaries that continued to be well maintained in the subepithelial stroma. Cells dispersed from conjunctival epithelium and co-cultured with feeder post-mitotic NIH3T3 fibroblasts formed mosaics displaying a basal epithelial phenotype. These cells expressed CD133 as revealed by RT-PCR. These organ cultures provide new opportunities to investigate epithelial reconstitution of the conjunctival surface and changes that may have occurred to their stem/precursor cells during adaptation to varying conditions in vitro.     

Reduction of Pb and Zn bioavailable forms in metal polluted soils due to paper mill sludge addition. Effects on Pb and Zn transferability to barley

In the last few years solidification/stabilisation of acidic soils polluted by heavy metals with low-cost sorbents has been investigated. Paper mill sludges are produced in large amounts and their disposal is a serious environmental problem. The possibility was therefore studied of using paper mill sludge as a stabilizer to reduce the bioavailable metal forms in polluted soils and thus the transferability of metals to plants (barley). We first investigated the sorbing properties of paper mill sludge for Zn(II) and Pb(II) and then their fractionation both in a polluted soil and in the same soil amended with paper mill sludge in order to check the decrease in mobile forms. Finally in both soils we tested the uptake of two metals by common barley in order to assess the performance of soil remediation from an ecological point of view. The addition of paper mill sludge to a soil contaminated by lead and zinc induces a decrease in the mobile forms of both metals, probably due to the presence in sludge of organic matter and kaolinite, which are able to bind the metals very strongly. The decrease in the mobile forms, which are the most readily available for uptake by plants, corresponds to a decrease in plant uptake.     

Purification and molecular characterization of antibacterial compounds produced by Lactobacillus murinus strain L1

AIMS: The aim of this work was to purify and characterize antibacterial compounds produced by Lactobacillus murinus strain L1. METHODS AND RESULTS: Antagonistic activity was observed in a deferred agar-spot assay against spoilage and pathogenic bacteria, but not against lactobacilli. The inhibitory activity occurred between pH 3.0 and 5.0, and was heat stable. The active compounds were purified by gel filtration chromatography and two peaks of antibacterial activity were observed using Bacillus cereus ATCC 11778 and Shigella sonnei ATCC 11060 as indicator strains. Two active low molecular weight compounds were responsible for this phenomenon and UV spectroscopy, gas chromatography and mass spectrometry were used to characterize them. One of them is lactic acid, while the other is a mono-substituted aromatic ring apparently constituted by group residues of m/z 192 linked in tandem to phenylalanine. CONCLUSIONS: Lactobacillus murinus produces at least two low molecular weight compounds active against B. cereus and Sh. sonnei. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first purification of a new broad-spectrum antibacterial compound from Lact. murinus which inhibits various pathogenic and food spoilage bacteria without acting on other lactobacilli. Using it as a biotechnological control agent of bacterial spoilage may be a promising possibility for the food industry.     

Screening of yeasts as probiotic based on capacities to colonize the gastrointestinal tract and to protect against enteropathogen challenge in mice

Probiotics are defined as viable microorganisms that exhibit a beneficial effect on the host's health when they are ingested. Two important criteria are used for selection of probiotic microorganisms: they must be able to survive in the gastrointestinal environment and to present at least one beneficial function (colonization resistance, immunomodulation or nutritional contribution). Generally, in vitro assays demonstrating these properties were used to select probiotics but it is unclear if the data can be extrapolated to in vivo conditions. In the present work, twelve Saccharomyces cerevisiae strains isolated from different environments (insect association, tropical fruit, cheese and "aguardente" production) and pre-selected for in vitro resistance to simulated gastrointestinal conditions were inoculated in germ-free mice to evaluate their real capacity to colonize the mammal digestive tract. Using these data, one of the yeasts (S. cerevisiae 905) was selected and tested in gnotobiotic (GN) and conventional (CV) mice for its capacity to protect against oral challenge with two enteropathogenic bacteria (Salmonella Typhimurium and Clostridium difficile). The yeast reached populational levels potentially functional in the gastrointestinal portions where the enteropathogens tested act. No antagonism against either pathogenic bacterium by the yeast was observed in the digestive tract of GN mice but, after challenge with S. Typhimurium, mortality was lower and liver tissue was better preserved in CV animals treated with the yeast when compared with a control group (p<0.05). Histopathological results of intestines showed that the yeast also presented a good protective effect against oral challenge with C. difficile in GN mice (p<0.05). In conclusion, among the 12 S. cerevisiae tested, strain 905 showed the best characteristics to be used as a probiotic as demonstrated by survival capacity in the gastrointestinal tract and protective effect of animals during experimental infections.