Antimicrobial/cytolytic peptides from the venom of the North African scorpion, Androctonus amoreuxi: Biochemical and functional characterization of natural peptides and a single site-substituted analog

The venoms of scorpions are complex cocktails of polypeptide toxins that fall into two structural categories: those that contain cysteinyl residues with associated disulfide bridges and those that do not. As the majority of lethal toxins acting upon ion channels fall into the first category, most research has been focused there. Here we report the identification and structural characterization of two novel 18-mer antimicrobial peptides from the venom of the North African scorpion, Androctonus amoreuxi. Named AamAP1 and AamAP2, both peptides are C-terminally amidated and differ in primary structure at just two sites: Leu?Pro at position 2 and Phe?Ile at position 17. Synthetic replicates of both peptides exhibited a broad-spectrum of antimicrobial activity against a Gram-positive bacterium (Staphylococcus aureus), a Gram-negative bacterium (Escherichia coli) and a yeast (Candida albicans), at concentrations ranging between 20µM and 150µM. In this concentration range, both peptides produced significant degrees of hemolysis. A synthetic replicate of AamAP1 containing a single substitution (His?Lys) at position 8, generated a peptide (AamAP-S1) with enhanced antimicrobial potency (3-5µM) against the three test organisms and within this concentration range, hemolytic effects were negligible. In addition, this His?Lys variant exhibited potent growth inhibitory activity (ID(50) 25-40µm) against several human cancer cell lines and endothelial cells that was absent in both natural peptides. Natural bioactive peptide libraries, such as those that occur in scorpion venoms, thus constitute a unique source of novel lead compounds with drug development potential whose biological properties can be readily manipulated by simple synthetic chemical means.

Identifying optimal sites for natural recovery and restoration of impacted biogenic habitats in a special area of conservation using hydrodynamic and habitat suitability modelling

Selection of sites for successful restoration of impacted shellfish populations depends on understanding the dispersion capability and habitat requirements of the species involved. In Strangford Lough, Northern Ireland, the horse mussel (Modiolus modiolus) biogenic reefs cover only a fraction of their historical range with the remaining reefs badly damaged and requiring restoration. Previous experimental trials suggest that translocation of horse mussels accelerates reef recovery and has therefore been proposed as a suitable restoration technique. We used a series of coupled hydrodynamic and particle dispersal models to assess larval dispersion from remnant and translocated populations to identify suitable areas for adult live M. modiolus translocation in Strangford Lough, Northern Ireland. A maximum entropy model (MAXENT) was used to identify if dispersing larvae could reach habitat suitable for adult M. modiolus. From these we predicted if translocated mussels will reseed themselves or be able to act as larval sources for nearby reefs. The dispersal models showed that the remnant M. modiolus populations are largely self-recruiting with little connectivity between them. The majority of larvae settled near the sources and movement was largely dependent on the tides and not influenced by wind or waves. Higher reef elevation resulted in larvae being able to disperse further away from the release point. However, larval numbers away from the source population are likely to be too low for successful recruitment. There was also little connectivity between the Irish Sea and Strangford Lough as any larvae entering the Lough remained predominantly in the Strangford Narrows. The areas covered by these self-seeding populations are suitable for M. modiolus translocation according to the MAXENT model. As a result of this work and in conjunction with other field work we propose a combination of total protection of all remaining larval sources and small scale translocations onto suitable substrata in each of the identified self-recruiting areas.

Sequence divergence of measles virus haemagglutinin during natural evolution and adaptation to cell culture

Phylogenetic analysis of the sequence of the H gene of 75 measles virus (MV) strains (32 published and 43 new sequences) was carried out. The lineage groups described from comparison of the nucleotide sequences encoding the C-terminal regions of the N protein of MV were the same as those derived from the H gene sequences in almost all cases. The databases document a number of distinct genotype switches that have occurred in Madrid (Spain). Well-documented is the complete replacement of lineage group C2, the common European genotype at that time, with that of group D3 around the autumn of 1993. No further isolations of group C2 took place in Madrid after this time. The rate of mutation of the H gene sequences of MV genotype D3 circulating in Madrid from 1993 to 1996 was very low (5 x 10(-4) per annum for a given nucleotide position). This is an order of magnitude lower than the rates of mutation observed in the HN genes of human influenza A viruses. The ratio of expressed over silent mutations indicated that the divergence was not driven by immune selection in this gene. Variations in amino acid 117 of the H protein (F or L) may be related to the ability of some strains to haemagglutinate only in the presence of salt. Adaptation of MV to different primate cell types was associated with very small numbers of mutations in the H gene. The changes could not be predicted when virus previously grown in human B cell lines was adapted to monkey Vero cells. In contrast, rodent brain-adapted viruses displayed a lot of amino acid sequence variation from normal MV strains. There was no convincing evidence for recombination between MV genotypes.

Arsenic removal from soil with high iron content using a natural surfactant and phosphate

An environment friendly arsenic removal technique from contaminated soil with high iron content has been studied. A natural surfactant extracted from soapnut fruit, phosphate solution and their mixture was used separately as extractants. The mixture was most effective in desorbing arsenic, attaining above 70 % efficiency in the pH range of 4–5. Desorption kinetics followed Elovich model. Micellar solubilization by soapnut and arsenic exchange mechanism by phosphate are the probable mechanisms behind arsenic desorption. Sequential extraction reveals that the mixed soapnut–phosphate system is effective in desorbing arsenic associated with amphoteric–Fe-oxide forms. No chemical change to the wash solutions was observed by Fourier transform-infrared spectra. Soil:solution ratio, surfactant and phosphate concentrations were found to affect the arsenic desorption process. Addition of phosphate boosted the performance of soapnut solution considerably. Response surface methodology approach predicted up to 80 % desorption of arsenic from soil when treated with a mixture of ≈1.5 % soapnut, ≈100 mM phosphate at a soil:solution ratio of 1:30.

Combining and integrating life /social sciences and citizen trainers in Nurse Education - a N. Ireland initiative

Before commencement of the academic year 2012/2013 the social sciences, public health and the biomedical sciences were taught to separate modules. This reinforced the idea off separate disciplines certainly for some of the younger students and a failure to appreciate the interconnectedness (whole person) perspective on health; separately modules taught and assessed in separate silos. There was limited understanding by the lecturers of the other areas that they were not teaching to -reflecting perhaps a dis-coordinated approach to health sciences (Mason and Whitehead 2003). As a result of significant discussion and interdisciplinary negotiation the life, social sciences public health/ health education were drawn together in the one module for the academic year 2012/13. The module provides the undergraduate students with an introduction to an understanding of Life Sciences, psychology, sociology and public health and their contribution within the context of nursing and midwifery. Each week’s teaching seeks to reflect against the other module delivered in first year - addressing clinical skills. The teaching is developing innovative e-learning approaches, including the use of a virtual community. The intention is to provide the student with a more integrated understanding and teaching to the individual’s health and to health within a social context (Lin 2001; Iles- Shih 2011). The focus is on health promotion rather than disease management. The module runs in three phases across the student’s first-year and teachers to the field of adult mental health, learning disability, children’s nursing and the midwifery students -progressively building on the student’s clinical experience. The predominant focus of the module remains on health and reflecting aspects of life and social life within N. Ireland. One of the particular areas of interest and an area of particular sensitivity is engaging the students to the context of the Northern Ireland civil unrest (the Troubles); this involves a co-educational initiative with service users, only previously attempted with social work students (Duffy 2012). The service users are represented by WAVE an organisation offering care and support to bereaved, traumatised or injured as a result of the violent civil conflict `the Troubles’. The `Troubles’ had ranged over an extended period and apart from the more evident and visual impact of death and injury, the community is marked by a disproportionate level of civil unrest, the extremes of bereavement, imprisonment, displacement antisocial behaviour and family dysfunction (Coulter et al. 2012). As co-educators with the School of Nursing and Midwifery, WAVE deliver a core lecture (augmented by online material), then followed by tutorials. The tutorials are substantially led by those who had been involved with and experienced loss and trauma as a result of the conflict (Health Service users) as `citizen trainers’ and provide an opportunity for them to share their experience and their recollection of personal interaction with nursing and midwifery students; in improving their understanding of the impact of `The Troubles’ on patients and clients affected by the events (Coulter et al. 2012) and to help better provide a quality of care cognisant of the particular needs of those affected by `the Troubles’ in N.Ireland. This approach is relatively unique to nursing in N. Ireland in that it involves many of those directly involved with and injured by the `Troubles’ as `citizen trainers’ and clearly reflects the School’s policy of progressively engaging with users and carers of nursing and midwifery services as co-educators to students (Repper & Breeze 2006). Only now could perhaps such a sensitive level of training to student nurses and midwives be delivered across communities with potential educative lessons for other communities experiencing significant civil unrest and sectarian conflict.

Dynamic Modeling and Interaction of Hybrid Natural Gas and Electricity Supply System in Microgrid

Natural gas (NG) network and electric network are becoming tightly integrated by microturbines in the microgrid. Interactions between these two networks are not well captured by the traditional microturbine (MT) models. To address this issue, two improved models for single-shaft MT and split-shaft MT are proposed in this paper. In addition, dynamic models of the hybrid natural gas and electricity system (HGES) are developed for the analysis of their interactions. Dynamic behaviors of natural gas in pipes are described by partial differential equations (PDEs), while the electric network is described by differential algebraic equations (DAEs). So the overall network is a typical two-time scale dynamic system. Numerical studies indicate that the two-time scale algorithm is faster and can capture the interactions between the two networks. The results also show the HGES with a single-shaft MT is a weakly coupled system in which disturbances in the two networks mainly influence the dc link voltage of the MT, while the split-shaft MT is a strongly coupled system where the impact of an event will affect both networks.