Biology and potential biogeochemical impacts of novel predatory flavobacteria

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2010Predatory bacteria are ubiquitous in aquatic environments and may be important players in the ecology and biogeochemistry of microbial communities. Three novel strains belonging to two genera of marine flavobacteria, Olleya and Tenacibaculum, were cultured from coastal sediments and found to be predatory on other bacteria on surfaces. Two published species of the genus Tenacibaculum were also observed to grow by lysis of prey bacteria, raising the possibility that predation may be a widespread lifestyle amongst marine flavobacteria, which are diverse and abundant in a variety of marine environments. The marine flavobacterial clade is known to include species capable of photoheterotrophy, scavenging of polymeric organic substances, pathogenesis on animals, the degradation and lysis of phytoplankton blooms and, now, predation on bacterial communities. Strains from the two genera were found to exhibit divergent prey specificities and growth yields when growing predatorily. Olleya sp. predatory cells accumulated to an order of magnitude greater cell densities than Tenacibaculum sp. cells on equivalent prey cell densities. Experiments were conducted to constrain the potential of the novel isolates to affect prey communities under more environmentally relevant conditions. An investigation of the minimum number of predatory cells needed to generate clearings of prey cells found that the inoculation of individual predatory flavobacteria cells can ultimately result in dense lytic swarms. In some cases, the susceptibility of particular prey species to lysis by a flavobacterial predator was found to vary based on the growth state of the prey cells or the presence of their spent growth media. A novel methodology for the experimental study of biofilms was used to assess the impact of exposure to predatory marine flavobacteria on the release of macronutrients from prey biofilms. The Olleya sp. predator had a stimulative effect on macronutrient release while the Tenacibaculum sp. did not, further suggesting the two groups of predators are adapted to different ecological niches.Support by the National Science Foundation (NSF) Division of Molecular and Cellular Biosciences Grant (MCB- 0348425), the MIT Student Assistance Fund, the Woods Hole Oceanographic Institution (WHOI) Academic Programs Office, WHOI Coastal Ocean Institute (COI) and WHOI Ocean Venture Fund grant, COI and the WHOI Ocean Life Institute

Environmental regulation and competitiveness

The potential relationship between domestic environmental regulation and international competitiveness has evoked various speculations. The common neoclassical train of thought is that strict environmental regulation is detrimental to the competitiveness of industry, and that it induces phenomena such as ecological dumping, ecological capital flight, and regulatory ‘chill’ in environmental standards. A different view is that strict environmental regulation triggers industry’s innovation potential, and subsequently increases its competitiveness. The impact of environmental regulation on competitiveness has been analyzed in terms of international capital movements, new firm formation, and international trade. This paper focuses on a statistically rigorous analysis of international trade studies, using a technique that is known as meta-analysis. The paper presents a statistically supported evaluation of the literature, in order to assess what the main conclusions regarding the relationship between environmental regulation and competitiveness are when it comes to studies on international trade flows. The synthesis of the literature is subsequently used to present guidelines for future primary research in this area

Bovine Hydatidosis in Eastern Part of Ethiopia

A cross-sectional study was conducted on bovine hydatidosis from November 2010 to March 2011 with the aims of investigating its occurrence, risk factors and economic losses in Dire Dawa municipality abattoir. The study revealed 20.05% occurrence of hydatidosis based on the postmortem examination of1536 cattle. Age related infection was significant as older animals were more infected (P<0.05, x2 = 27.496).Among the lungs, liver, heart, spleen and kidneys examined in each carcass, the cysts were distributed in the lungs and livers only. Out of 1852 cysts, 1340 (72.3%) were found in liver while512 (27.7%) in lungs. Five hundred and twenty (53.94%) of 964 hydatid cysts were small, while268 (27.80%) medium and 176 (18.25%) large. These cysts were further characterized as fertile (80.08.7%), sterile (17.3%) and calcified (2.85%) and 53.7% of fertile cysts were viable. Based on the study, the direct economic loss was estimated to be 23,876 Ethiopian Birrs. Presence of hydatid cysts in edible organs has great public health significance as consumption of undercooked/raw meat is still in practice in many parts of Ethiopia.Keywords: Abattoir, Bovine, Carcass, Cysts, Hydatidosis, Eastern Ethiopia

Bibliography on HIV/AIDS in Ethiopia and Ethiopians in the Diaspora: The 2008 Update

This is the sixth update of the bibliography on HIV/AIDS in Ethiopia and Ethiopians in the Diaspora, which was originally published in this journal in 2003. That bibliography covered published and unpublished work on HIV/AIDS and related health conditions (e.g., other sexually transmitted infections, tuberculosis) for the period 1972 to 2002. Five subsequent updates werepublished in 2004, 2005, 2006, 2007 and 2008. The present update extends the bibliography to cover references not listed in previous updates and those recent publications or presentations that appeared in 2008

Magnitude and associated factors of virological failure among children on ART in Bahir Dar Town public health facilities, Northwest Ethiopia: a facility based cross-sectional study

Background Despite the rapid scale-up of antiretroviral therapy, virologic failure has become global public health concern and challenge, especially in developing countries. Viral load monitoring is an important approach to identify treatment failure and develop public health interventions in children receiving antiretroviral therapy. Thus, this study aims to assess the magnitude and associated factors of virological failure among children on antiretroviral therapy. Methods A facility-based cross-sectional study was conducted among 399 HIV-positive children on antiretroviral therapy from 2016 to 2019 in Bahir Dar Town public health facilities. Data were extracted from children’s charts using a standardized data extraction tool, adapted from ART intake and follow-up forms. Data were entered using Epi-Data Version 3.1, and analyzed using SPSS Version 25. Bivariable and multivariable binary logistic regression models were done to identify factors associated with virological failure. Variables with p-values < 0.25 were fitted into the multivariable analysis. Finally, variables with p-values <0.05 were considered as statistically significant factors. Results The period prevalence of virological failure was found to be 14.8% (95% CI: 11.5–19.3%). Opportunistic infections (AOR = 2.19, CI: 1.13–4.25), history of treatment interruption and restart (AOR = 2.21, CI: 1.09–4.54), younger age (AOR = 2.42, CI: 1.02–5.74), poor/fair ART adherence (AOR = 2.19, CI: 1.05–4.57), and advanced baseline WHO clinical staging (AOR = 2.32, CI: 1.14–4.74) were found to be factors significantly associated with virological failure. Conclusion The magnitude of virological failure among HIV-infected children remained high. Children with poor/fair ART adherence, history of treatment interruption, advanced baseline WHO clinical staging, younger age, and opportunistic infections were significantly associated with virologic failure. Thus, special attention should be given to children who had poor/fair ART adherence and presenting with opportunistic infections

Using Data on Social Influence and Collective Action for Parameterizing a Geographically-Explicit Agent-Based Model for the Diffusion of Soil Conservation Efforts

Social influence affects individual decision-making on soil conservation. Understanding the emergent diffusion of collective conservation effort is relevant to natural resource management at the river basin level. This study focuses on the effect of subjective norms and collective action on the diffusion of Soil Conservation Effort (SCE) in the Lake Naivasha basin (Kenya) for the period 1965–2010. A geographically-explicit Agent-Based Model (ABM) version of the CONSUMAT model was developed: the CONSERVAT model. In our model, we have represented heterogeneity in the physical environment and in the social network using empirical data. To parameterize the model, physical data, and social data from a household survey (n = 307) were used. Model simulation results show that it is possible to reproduce empirical spatiotemporal diffusion patterns of SCE levels which are quite sensitive to the way in which social survey data are used to initialize the model. Overall, this study demonstrates (i) that social survey data can effectively be used for parameterization of a geographically-explicit ABM, and (ii) that empirical knowledge on natural environment characteristics and social phenomena can be used to build an agent-based model at the river basin level. This study is an important first step towards including subjective norms for evaluating the effectiveness of alternative policy strategies for natural resource management.</p

Mental health stigma and discrimination in Ethiopia:evidence synthesis to inform stigma reduction interventions

BACKGROUND: People with mental illnesses are at an increased risk of experiencing human rights violations, stigma and discrimination. Even though mental health stigma and discrimination are universal, there appears to be a higher burden in low- and middle-income countries. Anti-stigma interventions need to be grounded in local evidence. The aim of this paper was to synthesize evidence on mental health stigma and discrimination in Ethiopia to inform the development of anti-stigma interventions.METHODS: This evidence synthesis was conducted as a part of formative work for the International Study of Discrimination and Stigma Outcomes (INDIGO) Partnership research program. Electronic searches were conducted using PubMed for scientific articles, and Google Search and Google Scholar were used for grey literature. Records fulfilling eligibility criteria were selected for the evidence synthesis. The findings were synthesized using a framework designed to capture features of mental health stigma to inform cultural adaptation of anti-stigma interventions.RESULTS: A total of 37 records (2 grey literature and 35 scientific articles) were included in the evidence synthesis. Some of these records were described more than once depending on themes of the synthesis. The records were synthesized under the themes of explanatory models of stigma (3 records on labels and 4 records on symptoms and causes), perceived and experienced forms of stigma (7 records on public stigma, 6 records on structural stigma, 2 records on courtesy stigma and 4 records on self-stigma), impact of stigma on help-seeking (6 records) and interventions to reduce stigma (12 records). Only two intervention studies assessed stigma reduction- one study showed reduced discrimination due to improved access to effective mental health care, whereas the other study did not find evidence on reduction of discrimination following a community-based rehabilitation intervention in combination with facility-based care.CONCLUSION: There is widespread stigma and discrimination in Ethiopia which has contributed to under-utilization of available mental health services in the country. This should be addressed with contextually designed and effective stigma reduction interventions that engage stakeholders (service users, service providers, community representatives and service developers and policy makers) so that the United Nations universal health coverage goal for mental health can be achieved in Ethiopia