Effect of an alkaloidal fraction of Tabernaemontana elegans (Stapf.) on selected micro-organisms

Ethnopharmacological relevance: Bacterial infections remain a significant threat to human health. Due to the emergence of widespread antibiotic resistance, development of novel antibiotics is required in order to ensure that effective treatment remains available. There are several reports on the ethnomedical use of Tabernaemontana elegans pertaining to antibacterial activity. Aim of the study: The aim of this study was to isolate and identify the fraction responsible for the antimicrobial activity in T. elegans (Stapf.) root extracts. Materials and methods: The active fraction was characterised by thin layer chromatography (TLC) and gas chromatography – mass spectrometry (GC-MS). Antibacterial activity was determined using the broth micro-dilution assay and antimycobacterial activity using the BACTEC radiometric assay. Cytotoxicity of the crude extract and fractions was assessed against primary cell cultures; lymphocytes and fibroblasts; as well as a hepatocarcinoma (HepG2) and macrophage (THP-1) cell line using the Neutral Red uptake and MTT assays. Results: The crude root extracts were found to contain a high concentration of alkaloids (1.2% w/w). GC-MS analysis identified the indole alkaloids, voacangine and dregamine, as major components. Antibacterial activity was limited to the Grampositive bacteria and Mycobacterium species, with MIC values in the range of 64 – 256 μg/ml. When combined with antibiotics, additive antibacterial effects were observed. Marked cytotoxicity to all cell lines tested was evident in the MTT and Neutral Red uptake assays, with IC50 values < 9.81 μg/ml.Conclusions: This study confirms the antibacterial activity of T. elegans and supports its potential for being investigated further for the development of a novel antibacterial compound.National Research Foundationhttp://www.elsevier.com/locate/jethphar

Clouds, shadows, or twilight? Mayfly nymphs recognise the difference

1. We examined the relative changes in light intensity that initiate night-time locomotor activity changes in nymphs of the mayfly, Stenonema modestum (Heptageniidae). Tests were carried out in a laboratory stream to examine the hypothesis that nymphs increase their locomotion in response to the large and sustained reductions in relative light intensity that take place during twilight but not to short-term daytime light fluctuations or a minimum light intensity threshold. Ambient light intensity was reduced over a range of values representative of evening twilight. Light was reduced over the same range of intensities either continuously or in discrete intervals while at the same time nymph activity on unglazed tile substrata was video recorded. 2. Nymphs increased their locomotor activity during darkness in response to large, sustained relative light decreases, but not in response to short-term, interrupted periods of light decrease. Nymphs did not recognise darkness unless an adequate light stimulus, such as large and sustained relative decrease in light intensity, had taken place. 3. We show that nymphs perceive light change over time and respond only after a lengthy period of accumulation of light stimulus. The response is much lengthier than reported for other aquatic organisms and is highly adaptive to heterogeneous stream environments

A population-based, cross-sectional study of the prevalence and correlates of sedentary behaviour of adults with intellectual disabilities

Background: High levels of sedentary behaviour have a negative impact on health and well-being. There is limited evidence on the prevalence and correlates of sedentary behaviour of adults with intellectual disabilities (ID). Methods: A population-based sample of adults with ID were invited to take part in a comprehensive health check programme. Demographic and health data were collected during a structured interview and physical examination. Screen time was used as a proxy measure of sedentary behaviour. Bivariate and multivariate statistical modelling examined correlates of screen time. Results: Fifty per cent of the 725 participants reported four or more hours of screen time per day. Male gender, higher levels of intellectual ability, mobility problems, obesity, not having hearing impairment and not having epilepsy were all significantly associated with higher screen time in the final multivariate model (R2 = 0.16; Hosmer–Lemeshow goodness of fit statistic P = 0.36). Conclusions: This is the first study to publish population-based data on the prevalence and correlates of sedentary behaviour in adults with ID. Compared with adults who do not have ID, adults with ID have higher levels, and different correlates, of sedentary behaviour. A better understanding of the social context of sedentary behaviour will inform the design of effective behaviour change programmes for adults with ID

‘What are you going to do, confiscate their passports?’ Professional perspectives on cross-border reproductive travel

Objective: This article reports findings from a UK-based study which explored the phenomenon of overseas travel for fertility treatment. The first phase of this project aimed to explore how infertility clinicians and others professionally involved in fertility treatment understand the nature and consequences of cross-border reproductive travel. Background: There are indications that, for a variety of reasons, people from the UK are increasingly travelling across national borders to access assisted reproductive technologies. While research with patients is growing, little is known about how ‘fertility tourism’ is perceived by health professionals and others with a close association with infertility patients. Methods: Using an interpretivist approach, this exploratory research included focussed discussions with 20 people professionally knowledgeable about patients who had either been abroad or were considering having treatment outside the UK. Semi-structured interviews were recorded, transcribed verbatim and subjected to a thematic analysis. Results: Three conceptual categories are developed from the data: ‘the autonomous patient’; ‘cross-border travel as risk’, and ‘professional responsibilities in harm minimisation’. Professionals construct nuanced, complex and sometimes contradictory narratives of the ‘fertility traveller’, as vulnerable and knowledgeable; as engaged in risky behaviour and in its active minimisation. Conclusions: There is little support for the suggestion that states should seek to prevent cross-border treatment. Rather, an argument is made for less direct strategies to safeguard patient interests. Further research is required to assess the impact of professional views and actions on patient choices and patient experiences of treatment, before, during and after travelling abroad

New enzymes with potential for PET surface modification

This work describes newly isolated organisms and their potential to modify the surface of polyethylene terephthalate (PET). Out of the different screening processes, four bacterial and five fungal strains were isolated. A PET model substrate was synthesized (bis (benzoyloxyethyl) terephthalate) and used in the screening process, mimicking the polymer in its crucial properties and having the advantage of defined hydrolysis products. On this model substrate, extracellular enzyme preparations from the isolated microorganisms showed a maximum activity of 8.54 nkat/L. All enzyme preparations showed esterase activity on p-nitrophenyl-acetate while no activity was found on p-nitrophenyl decanoate or p-nitrophenyl palmitate. Increased hydrophilicity of PET fabrics after enzyme treatment was found based on rising height and water dissipation measurements

The Relational Power of Education: The immeasurability of knowledge, value and meaning

Recognizing the challenge of adequate evaluation in higher education, this essay introduces some of the critical, alternative-seeking conversation about educational measurement. The thesis is that knowledge, value, and meaning emerge in the relational dynamics of education, thus requiring complex approaches to evaluation, utilizing relational criteria. The method of the essay is to analyse two educational case studies à à à ¢ a travel seminar and a classroom course à à à ¢ in dialogue with educational literature and a process-relational philosophy of education. Building from this analysis, the essay concludes with proposals for relational criteria of evaluation: relations with self, community and culture, difference, earth, and social structures

Topological constraints strongly affect chromatin reconstitution in silico

The fundamental building block of chromatin, and of chromosomes, is the nucleosome, a composite material made up from DNA wrapped around a his-tone octamer. In this study we provide the first com-puter simulations of chromatin self-assembly, start-ing from DNA and histone proteins, and use these to understand the constraints which are imposed by the topology of DNA molecules on the creation of a polynucleosome chain. We take inspiration from the in vitro chromatin reconstitution protocols which are used in many experimental studies. Our simulations indicate that during self-assembly, nucleosomes can fall into a number of topological traps (or local folding defects), and this may eventually lead to the forma-tion of disordered structures, characterised by nu-cleosome clustering. Remarkably though, by intro-ducing the action of topological enzymes such as type I and II topoisomerase, most of these defects can be avoided and the result is an ordered 10-nm chromatin fibre. These findings provide new insight into the biophysics of chromatin formation, both in the context of reconstitution in vitro and in terms of the topological constraints which must be overcome during de novo nucleosome formation in vivo, e.g. following DNA replication or repair