Conformational energy calculations of the pentapeptide PHE-DPHE-ASN-GLN-TYR of Tyrocidine

By virtue of employing a modified version of a popular program for the calculation of polypeptide conformational energies, the lowest energy conformation of the tyrocidine molecule is being sought. This antibiotic molecule, a cyclic decapeptide, invited study due to its role in the process of bacterial sporulation in the Bacillus Brevis ATCC 818!2 strain. In the process of performing this investigation, lists of monopeptide lowest energy conformations, as determined by x-ray crystallographic studies, were combined to yield all possible combinations of half of the polypeptide chain. Beginning with a dipeptide, the conformations of lowest energy were calculated within a \u27local-minimum\u27 range; hereafter, a tripeptide was created from this dipeptide, as specified above, and similar calculations were performed. Finally, the tripeptide and a dipeptide calculated previously were then combined to yield the pentapeptide PHE-DPHE-ASN-GLN-TYR, which then underwent minimizing calculations to yield a set of 11 conformations, one of which possessed a probability of existence of 51.8%. The resulting lowest energy conformations of the pentapeptide will be joined with a pentapeptide from the lowest energy minima of gramicidin-S, PRO-DPHE-LEU-ORN-VAL, to yield the tyrocidine conformation

Microbial transformations of selenite by methane-oxidizing bacteria

Abstract Methane oxidizing bacteria are well known for their role in the global methane cycle and their potential for microbial transformation of wide range of hydrocarbon and chlorinated hydrocarbon pollution. Recently, it has also emerged that methane-oxidizing bacteria interact with inorganic pollutants in the environment. Here we report what we believe to be the first study of the interaction of pure strains of methane-oxidizing bacteria with selenite. Results indicate that the commonly used laboratory model strains of methane oxidizing bacteria, Methylococcus capsulatus (Bath) and Methylosinus trichosporium OB3b are both able to reduce the toxic selenite (SeO32-) but not selenate (SeO42-) to red spherical nanoparticulate elemental selenium (Se0), which was characterised via EDX and EXAFS. The cultures also produced volatile selenium-containing species, which suggests that both strains may have an additional activity that can either transform Se0 or selenite into volatile methylated forms of selenium. Transmission electron microscopy (TEM) measurements and experiments with the cell fractions: cytoplasm, cell wall and cell membrane show that the nanoparticles are formed mainly on the cell wall. Collectively these results are promising for the use of methane-oxidizing bacteria for bioremediation or suggest possible uses in the production of selenium nanoparticles for biotechnology

‘Shades of Grey’: The Ethics of Social Work Practice in Relation to Un-prescribed Anabolic Androgenic Steroid Use

© 2018, © 2018 British Association of Social Workers. This paper reflects on some of the ethical dilemmas that social workers face when assessing risk in relation to those using substances. It explores how legislation and societal factors can impact not just on people’s choices and decisions but also on their ‘vulnerability’ and access to services. Vulnerability, a contested term, is linked, in this paper, to assessment of risk. There are ethical issues that arise when assessing risk with people who use Anabolic Androgenic Steroids (AAS) from both service user and professional perspectives. These ethical issues concern a person’s right to choose and make potentially harmful decisions. The paper argues that using substances such as AAS in and of itself does not suffice to make a person vulnerable but this does not mean that people using AAS are not in need of support. It suggests that there may be some groups of people who are more at risk to starting AAS use and that social workers should be aware of these. It also recommends the need for further qualitative research to understand the reasons for starting use and support to help people stop using AAS

Evidence-based Kernels: Fundamental Units of Behavioral Influence

This paper describes evidence-based kernels, fundamental units of behavioral influence that appear to underlie effective prevention and treatment for children, adults, and families. A kernel is a behavior–influence procedure shown through experimental analysis to affect a specific behavior and that is indivisible in the sense that removing any of its components would render it inert. Existing evidence shows that a variety of kernels can influence behavior in context, and some evidence suggests that frequent use or sufficient use of some kernels may produce longer lasting behavioral shifts. The analysis of kernels could contribute to an empirically based theory of behavioral influence, augment existing prevention or treatment efforts, facilitate the dissemination of effective prevention and treatment practices, clarify the active ingredients in existing interventions, and contribute to efficiently developing interventions that are more effective. Kernels involve one or more of the following mechanisms of behavior influence: reinforcement, altering antecedents, changing verbal relational responding, or changing physiological states directly. The paper describes 52 of these kernels, and details practical, theoretical, and research implications, including calling for a national database of kernels that influence human behavior