Biology subjects

Abebe, A.

Publications and source records attributed to Abebe, A..

5 recordsLinked to original sources

bioRxiv2026

Impact of Fragmentation on the Metapopulation Structure of wild olive

Habitat fragmentation disrupts metapopulation dynamics by altering environmental conditions and constraining demographic processes critical for persistence and recruitment. In the dry Afromontane forests of northern Ethiopia, we investigated how natural and anthropogenic drivers affect seedlings, saplings, and mature tree dynamics of Olea europaea subsp. cuspidata across 34 patches. We used dynamic occurrence models to quantify effects of patch area, altitude, browsing, and disturbance. Our results indicate that high disturbance reduces seedling occurrence probability lower disturbance sites has seedling in 30% of survey plots, high disturbance would bring this down to 10% (median = -1.322, 95% CI: -2.703 to -0.283). Disturbance makes seedling less likely to persist, while large patch size help seedling persists (median = -0.93, 9 5 % CrI -1.87 - -0.02). For mature individuals, disturbance was the only significant predictor of occurrence probability, suggesting greater resistance to environmental and spatial variability compared to earlier life stages. These findings emphasize that while mature trees display resilience, the successful regeneration of Olea europaea is constrained by disturbance, but current level of browsing is not a threat. Management strategies for conservation should prioritise reducing disturbance through community engagement and forest stewardship to enhance regeneration potential and ensure long-term population viability.

ecology↗

bioRxiv2026

MaRNAV-1 infection of Plasmodium vivax is associated with increased parasite transmission and host inflammatory responses

MaRNAV-1 is an RNA virus recently identified in Plasmodium vivax-infected samples, but definitive evidence that it infects the parasite and influences malaria pathogenesis remains unknown. Here, we demonstrate that MaRNAV-1 is an intracellular virus that is present in P. vivax at various stages of its life cycle, including blood, sporozoite, and liver stages. Viral prevalence varied geographically between Cambodian and Ethiopian parasites. MaRNAV-1 presence and load were positively associated with parasite transmission potential, as reflected by increased gametocyte abundance and higher oocyst prevalence and intensity in membrane feeding assays. MaRNAV-1 loads were higher in symptomatic compared to asymptomatic infections, and higher MaRNAV-1 loads were associated with elevated body temperature, independently of parasitemia. MaRNAV-1 infection elicits an antibody response and is associated with dendritic cell activation, a shift from Th2 to a Th1-driven immune response, and an increased frequency of double-negative B cells. Accordingly, MaRNAV-1-infected patients had higher concentrations of circulating cytokines, such as IFN-{gamma}, CXCL10, IL-1RA, and IL-6, independently of parasitemia. Together, these findings demonstrate that MaRNAV-1 is a genuine parasite-infecting virus associated with increased parasite transmission potential and with modulation of clinical outcomes in, and host immune response to, P. vivax infections. Our study broadens the conventional view of host-pathogen interactions in malaria by revealing complex virus-parasite-host relationships.

microbiology↗

bioRxiv2026

Autolab HBH: A Rapid Hyperbaric Heating Device for Streamlined, PCR-Ready Sample Preparation Across Diverse Biological Matrices and Organisms

Traditional nucleic acid extraction methods are costly, lengthy, and highly variable depending on the complexity of the sample matrix or the organism of interest. Workflows may exceed twenty steps, require separate kits for RNA and DNA, and demand expensive instrumentation, creating barriers to both speed and scalability. The AutolabTM HBH system addresses these limitations by using hyperbaric heating (HBH) to achieve temperatures above 100 {degrees}C in a sealed, pressurized environment through induction heating, enabling rapid lysis of diverse organisms and neutralization of macromolecular PCR inhibitors within minutes. The combination of extreme heat and HBH-optimized lyophilized reagents rapidly inactivates nucleases while preserving free nucleic acids. The workflow is streamlined to two steps: heating up to 1 mL of sample in the proprietary HBH bullet, followed by a brief centrifugation to pellet additives. The resulting supernatant is immediately compatible with real-time reverse transcription polymerase chain reaction (RT-PCR) and other downstream molecular assays. Here, we evaluate the systems broad compatibility with diverse sample buffers, matrices, and organisms. Comparative testing was conducted alongside Qiagen extraction methods to benchmark performance.

molecular biology↗

bioRxiv2021

The natural adaptation and human selection history of African sheep genomes

African sheep manifest diverse but distinct physio-anatomical traits which are the outcomes of natural- and human-driven selection. Here, we generated 34.8 million variants from 150 indigenous African sheep genomes sequenced at an average depth of [~]54x for 130 samples (Ethiopia, Libya) and [~]10x for 20 samples (Sudan), representing sheep from diverse environments, tail morphology and post-Neolithic introductions to Africa. Phylogenetic and model-based admixture analysis provided evidence of four genetic groups that correspond to altitudinal geographic origins and tail morphotypes. Comparative genomic analysis identified targets of selection spanning conserved haplotype structures overlapping genes and gene families relating to hypoxia responses, caudal vertebrae and tail skeleton length, ear morphology, and tail fat-depot structure. Our findings provide novel insights underpinning variation and response to human selection and environmental adaptation, and possible pleiotropic gene interactions in indigenous African sheep genomes, which guaranteed the successful establishment of the species on the continent.

genomics↗

bioRxiv2019

Undiagnosed and diagnosed hypertension in a community setting at Hosanna town: Uncovering the burden

BackgroundHypertension is a leading cause of cardio-vascular diseases and its attributed mortality. No previous study, however, assessed the prevalence and associated factors of hypertension in the study area. MethodsWe recruited a representative sample of 627 adult individuals from selected kebeles of Hosanna town. A multi-stage sampling technique was employed in the study. A structured questionnaire using the WHO STEPS approach was employed to conduct a face to face interview and physical measurements. For each participant, we measured blood pressure two times after giving 10 minutes breaks between the measurements and we took the average. Hypertension status was defined as "systolic blood pressure [≥]140mmhg and/or diastolic blood pressure [≥]90mmhg". Undiagnosed hypertension was defined as participants who had raised blood pressure on measurement, but not aware of it before. We used Multivariable logistic regression model to determine factors associated with hypertension. ResultsThe overall prevalence of hypertension was found to be 17.2% (95% CI 14.5 - 19.9), 19.3% among men and 14.2% among women, of which 10.2% were unaware of it before. Hypertension was significantly associated with old age [≥]35 years, excess alcohol intake, consumption of saturated oil/fat), consumption of unspecified different types of oil/fat and overweight/obesity. ConclusionThe prevalence of hypertension (both diagnosed and undiagnosed) in the town is unacceptably high. This is also related to modifiable risk factors like excessive alcohol intake, overweight/obesity and consumption of saturated fat/oil. Therefore, designing health information provision systems on the risk factors of hypertension and promotion of good health practices should be considered. Moreover, the health departments should facilitate blood pressure screening programs at community levels to identify and treat undiagnosed hypertension.

epidemiology↗