Characterization and distribution of esterase activity in activated sludge

The location and activity of esterase enzymes in activated Sludge from three Municipal wastewater treatment plants were characterized using model Substrate, and denaturing and nondenaturing polyacrylamide gel electrophoresis (PAGE) Of particulate, freeze thaw (primarily periplasmic enzymes and those associated with outer cell surfaces) and extracellular fractions of activated sludge bacteria. Particulate and freeze thaw fractions had a similar spectrum of substrate specificity and contained significant levels of protein and esterase activity against model substrates, C-2 C-18 monoesters or p-nitrophenol and C-2 C-8 diesters of fluorescein. Esterase activity was highest with substrates that had short alkyl chains (C-4) and decreased as the chain lengths increased beyond C-8. Extracellular fractions contained very low levels of protein

Early childhood feeding practices and dental caries among Australian preschoolers

Published: 11 February 2020BACKGROUND:Recent reviews have proposed a causal relationship between prolonged breastfeeding and early childhood caries (ECC), but the evidence to date is inconsistent, with few cohort studies and limited investigation of key confounders. OBJECTIVE:This study aimed to investigate the relationship between dietary practices and early childhood caries in a birth cohort of Australian preschoolers. METHODS:Participants underwent a standardized dental examination at 2-3 y of age to determine the prevalence of ECC (based on the presence of decayed, missing, or filled tooth surfaces). Breastfeeding practices were reported at 3, 6, 12, and 24 mo of age. Intakes of free sugars were assessed at 1 and 2 y of age. Multivariable regression models generated prevalence ratios (PR) for the association between ECC and breastfeeding duration, and between ECC and sleep feeding practices at 1 y, controlling for sociodemographic factors and free sugars intake. RESULTS:There was no independent association between breastfeeding beyond 1 y of age and ECC (PR 1.42, 95% CI: 0.85, 2.38), or between breastfeeding to sleep and ECC (PR 1.12, 95% CI: 0.67, 1.88), although the direction of effect was suggestive of an association. The only factors independently associated with ECC were high free sugars intakes (PR 1.97, 95% CI: 1.13, 3.44), and greater socioeconomic disadvantage (PR 2.15, 95% CI: 1.08, 4.28). Most participants who were breastfed at 1 y of age had ceased by 18 mo or 2 y. CONCLUSIONS:Breastfeeding practices were not associated with ECC. Given the wide-ranging benefits of breastfeeding, and the low prevalence of sustained breastfeeding in this study and Australia in general, recommendations to limit breastfeeding are unwarranted, and breastfeeding should be promoted in line with global and national recommendations. To reduce the prevalence of early childhood caries, improved efforts are needed to limit foods high in free sugars.Gemma Devenish, Aqif Mukhtar, Andrea Begley, A John Spencer, W Murray Thomson, Diep Ha, Loc Do, and Jane A Scot

Calculations of surface core level shifts for the lanthanides

Available from British Library Document Supply Centre- DSC:6609.025(DL/SCI/P--667/T) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Dandruff-associated Malassezia genomes reveal convergent and divergent virulence traits shared with plant and human fungal pathogens

Fungi in the genus Malassezia are ubiquitous skin residents of humans and other warm-blooded animals. Malassezia are involved in disorders including dandruff and seborrheic dermatitis, which together affect >50% of humans. Despite the importance of Malassezia in common skin diseases, remarkably little is known at the molecular level. We describe the genome, secretory proteome, and expression of selected genes of Malassezia globosa. Further, we report a comparative survey of the genome and secretory proteome of Malassezia restricta, a close relative implicated in similar skin disorders. Adaptation to the skin environment and associated pathogenicity may be due to unique metabolic limitations and capabilities. For example, the lipid dependence of M. globosa can be explained by the apparent absence of a fatty acid synthase gene. The inability to synthesize fatty acids may be complemented by the presence of multiple secreted lipases to aid in harvesting host lipids. In addition, an abundance of genes encoding secreted hydrolases (e.g., lipases, phospholipases, aspartyl proteases, and acid sphingomyelinases) was found in the M. globosa genome. In contrast, the phylogenetically closely related plant pathogen Ustilago maydis encodes a different arsenal of extracellular hydrolases with more copies of glycosyl hydrolase genes. M. globosa shares a similar arsenal of extracellular hydrolases with the phylogenetically distant human pathogen, Candida albicans, which occupies a similar niche, indicating the importance of host-specific adaptation. The M. globosa genome sequence also revealed the presence of mating-type genes, providing an indication that Malassezia may be capable of sex.