Feedback regulation between atypical E2Fs and APC/CCdh1 coordinates cell cycle progression.

E2F transcription factors control the oscillating expression pattern of multiple target genes during the cell cycle. Activator E2Fs, E2F1-3, induce an upswing of E2F targets, which is essential for the G1-to-S phase transition, whereas atypical E2Fs, E2F7 and E2F8, mediate a downswing of the same targets during late S, G2, and M phases. Expression of atypical E2Fs is induced by E2F1-3, but it is unknown how atypical E2Fs are inactivated in a timely manner. Here, we demonstrate that E2F7 and E2F8 are substrates of the anaphase-promoting complex/cyclosome (APC/C). Removal of CDH1, or mutating the CDH1-interacting KEN boxes, stabilized E2F7/8 from anaphase onwards and during G1. Expressing KEN mutant E2F7 during G1 impairs S phase entry and eventually results in cell death. Furthermore, we show that E2F8, but not E2F7, interacts also with APC/C(C) (dc20). Importantly, atypical E2Fs can activate APC/C(C) (dh1) by repressing its inhibitors cyclin A, cyclin E, and Emi1. In conclusion, we discovered a feedback loop between atypical E2Fs and APC/C(C) (dh1), which ensures balanced expression of cell cycle genes and normal cell cycle progression.

Occurrence and antimicrobial resistance pattern of E. coli O157:H7 isolated from foods of Bovine origin in Dessie and Kombolcha towns, Ethiopia.

E. coli are frequently isolated food-borne pathogens from meat, milk, and their products. Moreover, there has been a significant rise in the antimicrobial resistance patterns of E. coli O157:H7 to commonly used antibiotics. A cross-sectional study was conducted from October 2019 to July 2021 to estimate prevalence and identify associated factors of E. coli and E. coli O157:H7 and to determine antibiotic resistance pattern of E. coli O157:H7 from foods of bovine origin in Dessie and Kombolcha towns. A total of 384 samples were collected. Systematic and simple random sampling techniques were employed for sampling carcasses and milking cows, respectively. E. coli and E. coli O157:H7 were detected according to recommended bacteriological protocols. E. coli O157:H7 strains were evaluated for in vitro antimicrobial susceptibility using agar disk diffusion method. Both descriptive and inferential statistical techniques were applied to analyze the data. Overall prevalence rates of E. coli and E. coli O157:H7 were 54.7% and 6.5%, respectively. Highest prevalence rates of E. coli (79.6%) and E. coli O157:H7 (16.7%) were obtained from carcass swabs and milk tank samples, respectively. Unlike E. coli O157:H7, a statistically significant difference in the E. coli prevalence (P<0.05) was observed among the different sample types. Multidrug resistance was observed among all isolates of E. coli O157:H7. All E. coli O157:H7 isolates (100.0%) were susceptible to Ampicillin, Sulfamethoxazole-trimethoprim, and Norfloxacin. On the contrary, all of the isolates (100%) were resistant to Penicillin G, Vancomycin, and Oxacillin. The current study indicated that different foods of bovine origin in the study area were unsafe for human consumption. Hence, good hygienic production methods should be employed to ensure the safety of foods of bovine origin.

Gross and histopathological studies on pulmonary lesions of camel (Camelus dromedarius) slaughtered at Addis Ababa abattoir, Ethiopia.

This study was carried out with the aim of identifying types of gross and histopathological lesions in lungs of camels slaughtered between October 2009 and April 2010 at Addis Ababa abattoir enterprise, Ethiopia. All camels were originated from Borana and Kereyu areas. A total of 387 slaughtered camel lungs were inspected during the study period. Of which, one or more gross lesions were encountered on 300 lungs. Lesions were further subjected for detail gross and histopathological examinations. The occurrence of pulmonary lesions was 77.5%. The gross and histopathological examination of these lesions had revealed 60.2% emphysema, 21.2% hydatidosis, 18.6% pneumonia, 10.6% atelectasis, 4.9% aspiration of blood, 3.9% pneumoconiosis, 2.6% pulmonary edema and congestion, 1.6% abscess, 1% pleurisy, and 0.8% granulomatous pneumonia. Most camels had one or more pulmonary lesions on postmortem examination, but they were apparently healthy during antemortem inspection. Therefore, the prevailing stressful environmental condition coupled with the existing poor level of veterinary service in camel-rearing areas of the country might reverse these hidden inactive lesions and thereby contributed for the higher occurrence of respiratory diseases in camels.

Isolation, characterization, and antimicrobial susceptibility pattern of Escherichia coli O157:H7 from foods of bovine origin in Mekelle, Tigray, Ethiopia.

Escherichia coli O157:H7 is an emerging and major zoonotic foodborne pathogen. It has an increasing concern about the spread of antimicrobial-resistant strains. This study aimed to isolate and characterize Shiga toxin-producing E. coli O157:H7 from raw milk, yogurt, and meat of bovine origin and determine their antimicrobial susceptibility pattern. A cross-sectional study was conducted from December 2014 to June 2015, and a total of 284 milk and meat samples were collected from different sources in Mekelle. The collected samples were analyzed for the presence of E. coli and Shiga toxin-producing E. coli O157:H7 and the determination of their antimicrobial susceptibility pattern following the standard bacteriological and molecular techniques and procedures and antimicrobial sensitivity test. Out of the total 284 samples, 70 (24.6%) were bacteriologically positive for E. coli and 14.3% were found to be Shiga toxin-producing E. coli O157:H7. Of note, 100% of E. coli isolates carried the pal gene and 41.7% eaeA gene (EHEC). Of these EHEC isolates, 40% and 60% were positive for stx1 and stx2, respectively. E. coli isolates showed the highest level of susceptibility to gentamycin (91.7%) but the highest level of resistance to amoxicillin (95.8%). Of the tested isolates, 18 (75%) of E. coli showed multidrug-resistant. This study revealed the occurrence of Shiga toxin-producing E. coli O157:H7 in foods of bovine origin in the study area. In conclusion, a nationwide phenotypic and molecular characterization, in-depth typing, and drug-resistant gene identification of E. coli O157:H7 should be undertaken.

Isolation, identification, and antimicrobial susceptibility pattern of Campylobacter jejuni and Campylobacter coli from cattle, goat, and chicken meats in Mekelle, Ethiopia.

Campylobacter jejuni and Campylobacter coli are globally recognized as a major cause of bacterial foodborne gastroenteritis. A cross-sectional study was conducted from October 2015 to May 2016 in Mekelle city to isolate, identify, and estimate the prevalence of C. jejuni and C. coli in raw meat samples and to determine their antibiotic susceptibility pattern. A total of 384 raw meat samples were randomly collected from bovine (n = 210), goat (n = 108), and chicken (n = 66), and isolation and identification of Campylobacter spp. were performed using standard bacteriological techniques and PCR. Antibiotic susceptibility test was performed using disc diffusion method. Of the total 384 raw meat samples, 64 (16.67%) were found positive for Campylobacter spp. The highest prevalence of Campylobacter spp. was found in chicken meat (43.93%) followed by bovine meat (11.90%) and goat meat (9.25%). The most prevalent Campylobacter spp. isolated from meat samples was C. jejuni (81.25%). The overall prevalence of Campylobacter in restaurants, butcher shops, and abattoir was 43.93%, 18.30%, and 9.30%, respectively. 96.8%, 81.25%, 75%, and 71% of the Campylobacter spp. isolates were sensitive to norfloxacin, erythromycin, chloramphenicol, and sulphamethoxazole-trimethoprim, respectively. However, 96.9%, 85.9%, and 50% of the isolates were resistant to ampicillin, amoxicillin, and streptomycin, respectively. Strains that developed multi-drug resistant were 68.7%. The result of this study revealed the occurrence of Campylobacter in bovine, goat, and chicken meats. Hence, there is a chance of acquiring infection via consumption of raw or undercooked meat. Thus, implementation of hygienic practices from a slaughterhouse to the retailers, proper handling and cooking of foods of meat are very important in preventing Campylobacter infection.

Isolation and Identification of Methicillin-Resistant Staphylococcus aureus (MRSA) from Milk in Shire Dairy Farms, Tigray, Ethiopia.

Antibiotic-resistant Staphylococcus aureus isolates pose a severe challenge to both veterinary and health professions and dairy cattle producers. Cross-sectional study was conducted from November 2014 to May 2015 to isolate and identify S. aureus from mastitic cows' milk and estimate the occurrence of MRSA in the dairy farms of Shire. Physical examination and California mastitis test were performed on a total of 220 dairy cows. Bacteriological isolation and identification and antibiogram testing were performed. Furthermore, multiplex polymerase chain reaction (PCR) was done for the detection of mec A and fem A genes. Out of the 220 dairy cows, 64 (29.09%) were positive for bovine mastitis, and of these, 32.81% were coagulase-positive S. aureus (CoPS). Antibiogram test results showed 100% of the isolates were resistant to penicillin G, nalidixic acid, and ampicillin, and 33.33% of the CoPS showed resistance to oxacillin (phenotypically MRSA positive). But 38.09% of the CoPS were found to be resistant and susceptible to vancomycin. PCR amplification of the seven phenotypically MRSA isolates revealed that 42.9% and 71.4% of them were found to carry fem A and mec A genes, respectively. The current study revealed the existence of alarming level of CoPS and development of multidrug resistance.

Parasites of pigs in two farms with poor husbandry practices in Bishoftu, Ethiopia.

A cross-sectional study was conducted from November 2011 to April 2012 on a total of 384 pigs from two privately owned intensive farms in Bishoftu, Ethiopia. The objectives of the study were to identify and determine the prevalence of common parasites of pigs. For the determination of gastrointestinal (GIT) parasites, faecal samples were collected from the study animals and subjected to standard parasitological examination techniques. Physical examination was conducted for the presence of skin parasitic lesions and skin scrapings were collected to determine prevalence of ectoparasites. The overall prevalence of GIT parasites in the pigs was 25% (96/384). Examination of faecal samples revealed the ova or oocysts of four different gastrointestinal parasites, namely Coccidia (12%), Strongyles (5.2%), Ascaris suum (4.9%) and Trichuris suis (2.9%). Mixed infection by at least two parasite species was observed in 3.65% (14/384) of the pigs. The only ectoparasite species identified was Sarcoptes scabiei var. suis, with a prevalence of 2.6%. This study indicates that pig parasites are a major problem in the study area, hence implementation of strategic control measures and appropriate hygienic management systems are recommended to reduce the prevalence of parasites.

Study on mange mite of camel in Raya-Azebo district, northern Ethiopia.

A cross-sectional study was carried out to determine the prevalence and species of camel mange mite infestation in Raya-Azebo district, Northern part of Ethiopia. Accordingly, Three hundred and eighty-four camels were examined and mange mite infestation was detected on 64 of camels. Only Sarcoptes scabiei var. cameli was identified as the only mite species in all skin scraping samples collected from the suspected mange mite lesions. There was significant difference in the prevalence of mange mite infestation between male and female camels (p < 0.05) but no significance difference was observed among the age groups and body condition score of camels (p > 0.05). The result indicated that camel mange mite infestation was a problem in northern part of Ethiopia, hence, further studies and strategic control measures are recommended to reduce the effect of mange mite infestation on camel husbandry.