Uterine involvement in guineapig salmonellosis

Of 334 mature breeding guineapigs, 53 (15.9%) died in a disease outbreak involving Salmonella typhimurium serotypes 1, 4, 5 and 12 : i : 1,2. The uterus was consistently involved. Nine other Salmonella-free mature female guineapigs when inoculated with a pure isolate from the outbreak, using the subcutaneous, intramuscular or per os route, succumbed to salmonellosis, reproducing signs and lesions observed during the outbreak. Abortion was not recorded during the outbreak despite many pregnant sows being affected. The isolate was sensitive to gentamicin, tetracycline, ampicillin and cefuroxime but resistant to co-trimoxazole, erythromycin and penicillin.     

Preliminary study on ecology of Bulinus jousseaumei in Schistosoma haematobium endemic rural community of Nigeria

The endemicity of schistosomiasis depends to a large extent on the presence of appropriate freshwater snail species with latent infection, and the quality of the microhabitat of the snails may favour or hinder their development and growth. Monthly in situ determinations of water temperature, pH, total dissolved solid (TDS), conductivity and dissolved oxygen were carried out. Monthly sampling of snails was also conducted. The planorbid snail species morphologically identified were Gyraulus costulatus, Biomphalaria pfeifferi, Bulinus globosus, B. senegalensis, B. jousseaumei, Segmentorbis augustus, Ferrisia sp and Lymnaea natalensis. The most abundant snail species was Gyraulus costulatus (62.2%). Snail density correlated positively with dissolved oxygen (r = 0.349; P = 0.266), while a negative relationship occurred between snail density and conductivity (r = ?0.064; P = 0.843). None of the B. globosus examined shed cercariae, while 12.5% of B. jousseaumei shed cercariae. The occurrence of B. jousseaumei in this study proves its presence in Nigeria and suggests its combined roles with B. globosus in the transmission of urogenital schistosomiasis in the endemic rural communities of Yewa North Local Government Area of Ogun State, Nigeria. Further studies on the geographical distribution of B. jousseaumei are recommended for better understanding of its epidemiological contribution to schistosomiasis in Nigeria.     

Leveraging knowledge engineering and machine learning for microbial bio-manufacturing

Genome scale modeling (GSM) predicts the performance of microbial workhorses and helps identify beneficial gene targets. GSM integrated with intracellular flux dynamics, omics, and thermodynamics have shown remarkable progress in both elucidating complex cellular phenomena and computational strain design (CSD). Nonetheless, these models still show high uncertainty due to a poor understanding of innate pathway regulations, metabolic burdens, and other factors (such as stress tolerance and metabolite channeling). Besides, the engineered hosts may have genetic mutations or non-genetic variations in bioreactor conditions and thus CSD rarely foresees fermentation rate and titer. Metabolic models play important role in design-build-test-learn cycles for strain improvement, and machine learning (ML) may provide a viable complementary approach for driving strain design and deciphering cellular processes. In order to develop quality ML models, knowledge engineering leverages and standardizes the wealth of information in literature (e.g., genomic/phenomic data, synthetic biology strategies, and bioprocess variables). Data driven frameworks can offer new constraints for mechanistic models to describe cellular regulations, to design pathways, to search gene targets, and to estimate fermentation titer/rate/yield under specified growth conditions (e.g., mixing, nutrients, and O₂). This review highlights the scope of information collections, database constructions, and machine learning techniques (such as deep learning and transfer learning), which may facilitate “Learn and Design” for strain development.     

Heartwater infection (cowdriosis) in a sitatunga (Tragelaphus spekei) in Nigeria

Cowdria ruminantium was isolated from a natural infection of heartwater in a captive sitatunga (Tragelaphus spekei) which died after a short illness in Jos Zoo, Nigeria. The isolate killed laboratory mice in a shorter period of time than did isolates of C. ruminantium recovered from natural cases in cattle. This is the first confirmed case of heartwater in a captive wild ruminant in Nigeria, where the disease is endemic.     

Exploring the binding interactions of structurally diverse dichalcogenoimidodiphosphinate ligands with α-amylase: Spectroscopic approach coupled with molecular docking

Postprandial hyperglycemia has orchestrated untimely death among diabetic patients over the decades and regulation of α-amylase activity is now becoming a promising management option for type 2 diabetes. The present study investigated the binding interactions of three structurally diverse dichalcogenoimidodiphosphinate ligands with α-amylase to ascertain the affinity of the ligands for α-amylase using spectroscopic and molecular docking methods. The ligands were characterized using ¹H and ³¹P NMR spectroscopy and CHN analysis. Diselenoimidodiphosphinate ligand (DY300), dithioimidodiphosphinate ligand (DY301), and thioselenoimidodiphosphinate ligand (DY302) quenched the intrinsic fluorescence intensity of α-amylase via a static quenching mechanism with bimolecular quenching constant (Kq) values in the order of x10¹¹ M^-1s^-1, indicating formation of enzyme-ligand complexes. A binding stoichiometry of n≈1 was observed for α-amylase, with high binding constants (Ka). α-Amylase inhibition was as follow: Acarbose > DY301>DY300>DY302. Values of thermodynamic parameters obtained at temperatures investigated (298, 304 and 310 K) revealed spontaneous complex formation (ΔG<0) between the ligands and α-amylase; the main driving forces were hydrophobic interactions (with DY300, DY301, except DY302). UV–visible spectroscopy and Förster resonance energy transfer (FRET) affirmed change in enzyme conformation and binding occurrence. Molecular docking revealed ligands interaction with α-amylase via some key catalytic site amino acid residues (Asp197, Glu233 and Asp300). DY301 perhaps showed highest α-amylase inhibition (IC₅₀, 268.11 ± 0.74 μM) due to its moderately high affinity and composition of two sulphide bonds unlike the others. This study might provide theoretical basis for development of novel α-amylase inhibitors from dichalcogenoimidodiphosphinate ligands for management of postprandial hyperglycemia.     

An epizootic infection of Citrobacter freundii in a guineapig colony: short communication

An epizootic infection of Citrobacter freundii in a guineapig colony is reported. From 1300 guineapigs maintained in a colony, a total of 115 guineapigs died. Lesions found postmortem were suggestive of acute pneumonia and enteritis. Citrobacter freundii was consistently isolated from necropsy specimens of lung, liver, spleen and intestines of the animals. The source of infection was not ascertained.