NADH and NADPH peroxidases as antioxidant defense mechanisms in intestinal sulfate-reducing bacteria.

Animal and human feces typically include intestinal sulfate-reducing bacteria (SRB). Hydrogen sulfide and acetate are the end products of their dissimilatory sulfate reduction and may create a synergistic effect. Here, we report NADH and NADPH peroxidase activities from intestinal SRB Desulfomicrobium orale and Desulfovibrio piger. We sought to compare enzymatic activities under the influence of various temperature and pH regimes, as well as to carry out kinetic analyses of enzymatic reaction rates, maximum amounts of the reaction product, reaction times, maximum rates of the enzyme reactions, and Michaelis constants in cell-free extracts of intestinal SRB, D. piger Vib-7, and D. orale Rod-9, collected from exponential and stationary growth phases. The optimal temperature (35 °C) and pH (7.0) for both enzyme's activity were determined. The difference in trends of Michaelis constants (Km) during exponential and stationary phases are noticeable between D. piger Vib-7 and D. orale Rod-9; D. orale Rod-9 showed much higher Km (the exception is NADH peroxidase of D. piger Vib-7: 1.42 ± 0.11 mM) during the both monitored phases. Studies of the NADH and NADPH peroxidases-as putative antioxidant defense systems of intestinal SRB and detailed data on the kinetic properties of this enzyme, as expressed by the decomposition of hydrogen peroxide-could be important for clarifying evolutionary mechanisms of antioxidant defense systems, their etiological role in the process of dissimilatory sulfate reduction, and their possible role in the development of bowel diseases.

The Incidence of Scabies and Head Lice and Their Associated Risk Factors among Displaced People in Cham Mishko Camp, Zakho City, Duhok Province, Iraq.

This study was conducted to estimate the incidence and the effects of associated risk factors of scabies and head lice on displaced people in Cham Mishko camp, Zakho city, Duhok Province, Iraq. The study included 1300 internally displaced people (IDPs) who visited the dermatology clinic and health care center in Cham Mishko camp from January 2018 to December 2019. Participants' bio-information was collected on special questionnaire form after receiving permission from the camp's health authorities and verbal consent from the participants. Monthly weather data were collected from Duhok Directorate of Meteorology and Seismology. The total rate of ectoparasites was 81.2% (45% for scabies and 36.2% for head lice). Ages from 1-10, 21-30, and 31-40 years showed the highest rates with scabies (48.1%, 46.7% and 46.1%, respectively), while the highest rates of head pediculosis were at ages from 1-10 and 11-20 years (40% and 36.6%, respectively). Scabies rate was slightly higher in males than females (46.6% vs. 43.4%), while the rate of head pediculosis was significantly higher in females than males (58.2% vs. 13.9%). Families with more than ten people showed the highest rates of scabies and head pediculosis (49.5% and 74.5%). Scabies was more common in cold months than in summer while head pediculosis was more common in hot months. The number of scabies and head pediculosis cases increased by 123 and 85 cases, respectively, in 2019. It is inferred that the effects of scabies and head pediculosis in IDPs will be considerable, with a higher carriage rate than other studies in Iraq.