Antimicrobial activity of marine bacteria associated with sponges from the waters off the coast of South East India

Seventy-five marine bacterial strains associated with four species of sponges (Echinodictyum sp., Spongia sp., Sigmadocia fibulatus and Mycale mannarensis) were isolated from the Tuticorin coast, Gulf of Mannar region. The agar-overlay method was used to screen for antibiotic production by these strains against four bacteria, viz., Bacillus subtilis, Escherichia coli, Vibrio parahaemolyticus, and Vibrio harveyi and one fungal pathogen, viz., Candida albicans. Twenty-one per cent of the bacterial strains were found to be antibiotic producers and their activities ranged from broad spectral to species specific. A strain coded SC3 was found to be highly potent and was mass cultured. The ethyl acetate extract of the culture broth was further fractionated by reverse phase HPLC and the active fraction identified. In addition, SC3 was subjected to morphological and physiological characterization. The results of the tests showed SC3 to be a Gram-positive rod, sporulating, motile, catalase and oxidase positive. Phylogenetic analysis based on comparative analysis of sequenced 16s rRNA of the active strains indicated a preponderance of bacteria belonging to Vibrio and Bacillus genera with 95-99% sequence similarities. To our knowledge this is the first report on phylogenetic identification of antibiotic producing bacteria associated with sponges from Indian waters.     

The guidelines for social life cycle assessment of products: just in time!

Purpose  

Authors of different sustainability journals, including authors of articles in past issues of the International Journal of Life Cycle Assessment have acknowledged the rising interest and the pressing need for a social and socio-economic life cycle assessment methodology and identified challenges in its development and implementation. Social life cycle assessment (LCA) allows identification of key issues, assessing, and telling the story of social conditions in the production, use, and disposal of products. In this article, the United Nations Environment Programme/The Society of Environmental Toxicology and Chemistry Guidelines for Social Life Cycle Assessment of Products will be presented.     

Plants as bioreactors for the production of vaccine antigens

Plants have been identified as promising expression systems for commercial production of vaccine antigens. In phase I clinical trials several plant-derived vaccine antigens have been found to be safe and induce sufficiently high immune response. Thus, transgenic plants, including edible plant parts are suggested as excellent alternatives for the production of vaccines and economic scale-up through cultivation. Improved understanding of plant molecular biology and consequent refinement in the genetic engineering techniques have led to designing approaches for high level expression of vaccine antigens in plants. During the last decade, several efficient plant-based expression systems have been examined and more than 100 recombinant proteins including plant-derived vaccine antigens have been expressed in different plant tissues. Estimates suggest that it may become possible to obtain antigen sufficient for vaccinating millions of individuals from one acre crop by expressing the antigen in seeds of an edible legume, like peanut or soybean. In the near future, a plethora of protein products, developed through ‘naturalized bioreactors’ may reach market. Efforts for further improvements in these technologies need to be directed mainly towards validation and applicability of plant-based standardized mucosal and edible vaccines, regulatory pharmacology, formulations and the development of commercially viable GLP protocols. This article reviews the current status of developments in the area of use of plants for the development of vaccine antigens.     

Determination of coefficient of friction for self-expanding stent-grafts

Migration of stent-grafts (SGs) after endovascular aneurysm repair of abdominal aortic aneurysms is a serious complication that may require secondary intervention. Experimental, analytical, and computational studies have been carried out in the past to understand the factors responsible for migration. In an experimental setting, it can be very challenging to correctly capture and understand the interaction between a SG and an artery. Quantities such as coefficient of friction (COF) and contact pressures that characterize this interaction are difficult to measure using an experimental approach. This behavior can be investigated with good accuracy using finite element modeling. Although finite element models are able to incorporate frictional behavior of SGs, the absence of reliable values of coefficient of friction make these simulations unreliable. The aim of this paper is to demonstrate a method for determining the coefficients of friction of a self-expanding endovascular stent-graft. The methodology is demonstrated by considering three commercially available self-expanding SGs, labeled as A, B, and C. The SGs were compressed, expanded, and pulled out of polymeric cylinders of varying diameters and the pullout force was recorded in each case. The SG geometries were recreated using computer-aided design modeling and the entire experiment was simulated in ABAQUS 6.8/STANDARD. An optimization procedure was carried out for each SG oversize configuration to determine the COF that generated a frictional force corresponding to that measured in the experiment. The experimental pullout force and analytically determined COF for SGs A, B, and C were in the range of 6-9 N, 3-12 N, and 3-9 N and 0.08-0.16, 0.22-0.46, and 0.012-0.018, respectively. The computational model predicted COFs in the range of 0.00025-0.0055, 0.025-0.07, and 0.00025-0.006 for SGs A, B, and C, respectively. Our results suggest that for SGs A and B, which are exoskeleton based devices, the pullout forces increase upto a particular oversize beyond which they plateau, while pullout forces showed a continuous increase with oversize for SG C, which is an endoskeleton based device. The COF decreased with oversizing for both types of SGs. The proposed methodology will be useful for determining the COF between self-expanding stent-grafts from pullout tests on human arterial tissue.     

Laboratory diagnosis of melioidosis: Past,present and future

Melioidosis is an emerging, potentially fatal disease caused by Burkholderia pseudomallei, which requires prolonged antibiotic treatment to prevent disease relapse. However, difficulties in laboratory diagnosis of melioidosis may delay treatment and affect disease outcomes. Isolation of B. pseudomallei from clinical specimens has been improved with the use of selective media. However, even with positive cultures, identification of B. pseudomallei can be difficult in clinical microbiology laboratories, especially in non-endemic areas where clinical suspicion is low. Commercial identification systems may fail to distinguish between B. pseudomallei and closely related species such as Burkholderia thailandensis. Genotypic identification of suspected isolates can be achieved by sequencing of gene targets such as groEL which offer higher discriminative power than 16S rRNA. Specific PCR-based identification of B. pseudomallei has also been developed using B. pseudomallei-specific gene targets such as Type III secretion system and Tat-domain protein. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry, a revolutionary technique for pathogen identification, has been shown to be potentially useful for rapid identification of B. pseudomallei, although existing databases require optimization by adding reference spectra for B. pseudomallei. Despite these advances in bacterial identification, diagnostic problems encountered in culture-negative cases remain largely unresolved. Although various serological tests have been developed, they are generally unstandardized “in house” assays and have low sensitivities and specificities. Although specific PCR assays have been applied to direct clinical and environmental specimens, the sensitivities for diagnosis remain to be evaluated. Metabolomics is an uprising tool for studying infectious diseases and may offer a novel approach for exploring potential diagnostic biomarkers. The metabolomics profiles of B. pseudomallei culture supernatants can be potentially distinguished from those of related bacterial species including B. thailandensis. Further studies using bacterial cultures and direct patient samples are required to evaluate the potential of metabolomics for improving diagnosis of melioidosis.     

Normal Grief and Complicated Bereavement Among Traumatized Cambodian Refugees: Cultural Context and the Central Role of Dreams of the Dead

This article profiles bereavement among traumatized Cambodian refugees and explores the validity of a model of how grief and post-traumatic stress disorder (PTSD) interact in this group to form a unique bereavement ontology, a model in which dreams of the dead play a crucial role. Several studies were conducted at a psychiatric clinic treating Cambodian refugees who survived the Pol Pot genocide. Key findings included that Pol Pot deaths were made even more deeply disturbing owing to cultural ideas about “bad death” and the consequences of not performing mortuary rites; that pained recall of the dead in the last month was common (76 % of patients) and usually caused great emotional and somatic distress; that severity of pained recall of the dead was strongly associated with PTSD severity (r = .62); that pained recall was very often triggered by dreaming about the dead, usually of someone who died in the Pol Pot period; and that Cambodians have a complex system of interpretation of dreams of the deceased that frequently causes those dreams to give rise to great distress. Cases are provided that further illustrate the centrality of dreams of the dead in the Cambodian experiencing of grief and PTSD. The article shows that not assessing dreams and concerns about the spiritual status of the deceased in the evaluation of bereavement results in “category truncation,” i.e., a lack of content validity, a form of category fallacy.