Publications by authors named "Zegeye E"

High-quality DNA with sufficient yield is the goal of DNA extraction protocols. We present an optimized, cost-effective method for extracting next-generation sequencing (NGS)-quality genomic DNA from Bacillus and Clostridium species using the chloroform-isoamyl approach. The protocol involves two main procedures: cultivation of the bacteria under appropriate conditions, followed by DNA extraction through cell lysis, phase separation, DNA precipitation, and cleanup.

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Species within the Bacillus cereus sensu lato group, known for their spore-forming ability, are recognized for their significant role in food spoilage and food poisoning. The spores of B. cereus are adorned with numerous pilus-like appendages, referred to as S-ENAs and L-ENAs.

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In pathogenic Bacillota, spores can form an infectious particle and can take up a central role in the environmental persistence and dissemination of disease. A poorly understood aspect of spore-mediated infection is the fibrous structures or 'endospore appendages' (ENAs) that have been seen to decorate the spores of pathogenic Bacilli and Clostridia. Current methodological approaches are opening a window on these long enigmatic structures.

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Enterotoxigenic Escherichia coli (ETEC) strains, which produce the heat-stable enterotoxin (ST) either alone or in combination with the heat-labile enterotoxin, contribute to the bulk of the burden of child diarrheal disease in resource-limited countries and are associated with mortality. Developing an effective vaccine targeting ST presents challenges due to its potent enterotoxicity, non-immunogenicity, and the risk of autoimmune reaction stemming from its structural similarity to the human endogenous ligands, guanylin, and uroguanylin. This study aimed to assess a novel synthetic vaccine carrier platform employing a single chemical coupling step for making human ST (STh) immunogenic.

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Article Synopsis
  • Genetic manipulation of Bacillus species, specifically B. thuringiensis and B. cereus, is challenging due to the difficulties in transforming plasmid DNA, especially larger shuttle plasmids like pMAD.
  • The article outlines effective protocols for transforming both small and large plasmid constructs into B. thuringiensis, emphasizing the importance of preparing electrocompetent cells using a cell wall-weakening agent and optimized wash solutions.
  • Additionally, it highlights that using unmethylated plasmid DNA significantly enhances the efficiency of transformation in B. thuringiensis.
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Heat-stable enterotoxin (ST) producing enterotoxigenic (ETEC) strains are among the top four enteropathogens associated with moderate-to-severe diarrhea in children under five years in low-to-middle income countries, thus making ST a target for an ETEC vaccine. However, ST must be mutated to abolish its enterotoxicity and to prevent a potential immunological cross-reaction due to its structural resemblance to the human peptides uroguanylin and guanylin. To reduce the risk of eliciting cross-reacting antibodies with our lead STh-A14T toxoid, L9 was chosen as an additional mutational target.

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The endospores (spores) of many sensu lato species are decorated with multiple hair/pilus-like appendages. Although they have been observed for more than 50 years, all efforts to characterize these fibers in detail have failed until now, largely due to their extraordinary resilience to proteolytic digestion and chemical solubilization. A recent structural analysis of endospore appendages (Enas) using cryo-electron microscopy has revealed the structure of two distinct fiber morphologies: the longer and more abundant "Staggered-type" (S-Ena) and the shorter "Ladder-like" type (L-Ena), which further enabled the identification of the genes encoding the S-Ena.

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Article Synopsis
  • Bacillus cereus sensu lato is a diverse group of Gram-positive bacteria known for their endospore formation and unique microscopic appendages called endospore appendages (Enas), whose identities and functions were previously unclear.
  • Researchers isolated these Enas from a food poisoning strain and identified two main types, S- and L-Ena, with S-Enas showing characteristics of a novel class of pili that provide resistance to extreme conditions.
  • The ena-gene cluster related to these appendages is widely present in various B. cereus species, indicating their potential importance in survival across different environments, including clinical and food-related contexts.
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Despite the discovery of the tubercle bacillus more than 130 years ago, its physiology and the mechanisms of virulence are still not fully understood. A comprehensive analysis of the proteomes of members of the human-adapted complex (MTBC) lineages 3, 4, 5, and 7 was conducted to better understand the evolution of virulence and other physiological characteristics. Unique and shared proteomic signatures in these modern, pre-modern and ancient MTBC lineages, as deduced from quantitative bioinformatics analyses of high-resolution mass spectrometry data, were delineated.

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The microbial catabolism of chitin, an abundant and ubiquitous environmental organic polymer, is a fundamental cog in terrestrial and aquatic carbon and nitrogen cycles. Despite the importance of this critical bio-geochemical function, there is a limited understanding of the synergy between the various hydrolytic and accessory enzymes involved in chitin catabolism. To address this deficit, we synthesized activity-based probes (ABPs) designed to target active chitinolytic enzymes by modifying the chitin subunits N-acetyl glucosamine and chitotriose.

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Soil microorganisms play fundamental roles in cycling of soil carbon, nitrogen, and other nutrients, yet we have a poor understanding of how soil microbiomes are shaped by their nutritional and physical environment. In this study, we investigated the successional dynamics of a soil microbiome during 21 weeks of enrichment on chitin and its monomer, -acetylglucosamine. We examined succession of the soil communities in a physically heterogeneous soil matrix as well as a homogeneous liquid medium.

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Infection with enterotoxigenic (ETEC) is a common cause of childhood diarrhea in low- and middle-income countries, as well as of diarrhea among travelers to these countries. In children, ETEC strains secreting the heat-stable toxin (ST) are the most pathogenic, and there are ongoing efforts to develop vaccines that target ST. One important challenge for ST vaccine development is to construct immunogens that do not elicit antibodies that cross-react with guanylin and uroguanylin, which are endogenous peptides involved in regulating the activity of the guanylate cyclase-C (GC-C) receptor.

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Background: While local context costing evidence is relevant for healthcare planning, budgeting and cost-effectiveness analysis, it continues to be scarce in Ethiopia. This study assesses the cost of providing a prevention of mother-to-child transmission of HIV/AIDS (PMTCT) service across heterogeneous prevalence (high, low) and socio-economic (urban, rural) contexts.

Methods: A total of 12 health facilities from six regions in Ethiopia were purposively selected from the latest 2012 antenatal sentinel HIV prevalence report.

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Multiple regulatory mechanisms including post-translational modifications (PTMs) confer complexity to the simpler genomes and proteomes of Mycobacterium tuberculosis (Mtb). PTMs such as glycosylation play a significant role in Mtb adaptive processes. The glycoproteomic patterns of clinical isolates of the Mycobacterium tuberculosis complex (MTBC) representing the lineages 3, 4, 5 and 7 were characterized by mass spectrometry.

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Background: Prevention of Mother-to-Child HIV Transmission (PMTCT) coverage has been low in Ethiopia and the service has been implemented in a fragmented manner. Solutions to this problem have mainly been sought on the supply-side in the form of improved management and allocation of limited resources. However, this approach largely ignores the demand-side factors associated with low PMTCT coverage in the country.

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Health technology assessment (HTA) has previously been implemented only in a fragmented manner in the Ethiopian health sector decision-making cycle, and the sector has been hampered by limited institutional capacity and skilled human resources to inform evidence-based decision making. The country is in the midst of widescale implementation of a community-based health insurance scheme and is preparing for the launch of a social health insurance scheme. The country continues to face a limited financial resource envelope, undergoing an epidemiological transition, and is facing a much greater burden of noncommunicable diseases, for which the essential health benefit package, defined 12 years ago, may no longer be suitable.

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Infection with enterotoxigenic (ETEC) is an important cause of diarrhea-related illness and death among children under 5 years of age in low- and middle-income countries (LMIC). Recent studies have found that it is the ETEC subtypes that produce the heat-stable enterotoxin (ST), irrespective of whether they also secrete the heat-labile enterotoxin (LT), which contribute most importantly to the disease burden in children from LMIC. Therefore, adding an ST toxoid would importantly complement ongoing ETEC vaccine development efforts.

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Enterotoxigenic (ETEC), which secretes the heat-stable toxin (ST) is among the four most important enteropathogens that cause moderate-to-severe diarrhea in children in low- and middle-income countries. ST is an intestinal molecular antagonist causing diarrhea and hence an attractive vaccine target. A non-toxic and safe ST vaccine should include one or more detoxifying mutations, and rigorous characterization of such mutants requires structurally intact peptides.

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HIV/AIDS impacts significantly on pregnant women and on children in Ethiopia. This impact has a multiplier effect on household economies and on productivity losses, and is expected to vary across rural and urban settings. Applying the human capital approach to data collected from 131 respondents, this study estimated productivity losses per HIV-positive pregnant woman-infant pair across urban and rural health facilities in Ethiopia, which in turn were used to estimate the national productivity loss.

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In order to decipher the nature of the slowly growing .tuberculosis) lineage 7, the differentially abundant proteins in strains of lineage 7 and lineage 4 were defined. Comparative proteomic analysis by mass spectrometry was employed to identify, quantitate and compare the protein profiles of strains from the two lineages.

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Importance: Comprehensive and timely monitoring of disease burden in all age groups, including children and adolescents, is essential for improving population health.

Objective: To quantify and describe levels and trends of mortality and nonfatal health outcomes among children and adolescents from 1990 to 2015 to provide a framework for policy discussion.

Evidence Review: Cause-specific mortality and nonfatal health outcomes were analyzed for 195 countries and territories by age group, sex, and year from 1990 to 2015 using standardized approaches for data processing and statistical modeling, with subsequent analysis of the findings to describe levels and trends across geography and time among children and adolescents 19 years or younger.

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Mismatch repair (MMR) is a near ubiquitous pathway, essential for the maintenance of genome stability. Members of the MutS and MutL protein families perform key steps in mismatch correction. Despite the major importance of this repair pathway, MutS-MutL are absent in almost all Actinobacteria and many Archaea.

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Background: Globally, economic evaluation (EE) is increasingly being considered as a critical tool for allocating scarce healthcare resources. However, such considerations are less documented in low-income countries, such as in Ethiopia. In particular, to date there has been no assessment conducted to evaluate the perception and practice of and barriers to health EE.

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Background: A deeply rooted phylogenetic lineage of Mycobacterium tuberculosis (M. tuberculosis) termed lineage 7 was discovered in Ethiopia. Whole genome sequencing of 30 lineage 7 strains from patients in Ethiopia was performed.

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A mechanistic mathematical model was developed to predict the performance of cationic polymers for flocculating salt water cultivated microalgae. The model was validated on experiments carried out with Neochloris oleoabundans and three different commercial flocculants (Zetag 7557®, Synthofloc 5080H® and SNF H536®). For a wide range of biomass concentrations (0.

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