Tens of millions of people in Southeast Asia drink groundwater contaminated with naturally occurring arsenic. How arsenic is released from the sediment into the water remains poorly understood. Here, we show in laboratory experiments that phosphate-limited cells of Burkholderia fungorum mobilize ancillary arsenic from apatite. We hypothesize that arsenic mobilization is a by-product of mineral weathering for nutrient acquisition. The released arsenic does not undergo a redox transformation but appears to be solubilized from the apatite mineral lattice during weathering. Analysis of apatite from the source area in the Himalayan basin indicates the presence of elevated levels of arsenic, with an average concentration of 210 mg/kg. The rate of arsenic release is independent of the initial dissolved arsenic concentration and occurs at phosphate levels observed in Bangladesh aquifers. We also demonstrate the presence of the microbial phenotype that releases arsenic from apatite in Bangladesh aquifer sediments and groundwater. These results suggest that microbial mineral weathering for nutrient acquisition could be an important mechanism for arsenic mobilization.
Infections caused by Campylobacter spp. continue to be a serious health burden worldwide. The importance of Campylobacter jejuni/coli for the development of acute gastroenteritis in Bulgaria has not been studied well yet, especially in early childhood. In this study, we report the incidence and the course of infection with C. jejuni/coli in early childhood and the antibiotic resistance of the clinical isolates tested. Bacteriological examination, followed by Multiplex polymerase chain reaction (PCR), was used. A total of 139 isolates of Campylobacter spp. were obtained from 368 fecal samples from children aged 0-5 years. The C. jejuni strains were 122 (87.8%), and C. coli strains 17 (12.2%). Antibiotic resistance was determined using disc diffusion tests. Resistance to tetracycline (38.1%) and ciprofloxacin (22.1%) was observed, as well as coresistance to both antibiotics (15.1%). There is a relatively high incidence of campylobacteriosis in hospitalized children with diarrhea. The increasing resistance to quinolone and non-quinolone antibiotics is of concern.
The article presents the results of experimental data characterizing the yield and quality of double-spore champignon mushrooms obtained by their cultivation on the substrate with the use of organic additives of plant and animal origin - waste of food and processing industries: sunflower husks, meat and buckwheat meal and coarse grains. The yield of mushrooms is estimated by periods of substrate preparation (winter and summer) and fruit-bearing waves. Higher yield of mushrooms of mushrooms of double-spore champignon was obtained on the substrate prepared in summer for two waves of fruiting. Assessment of the quality of mushrooms involved studying the content of protein, fiber, fat and ash elements (potassium, phosphorus, calcium, sodium and magnesium). The results show that sunflower husk and meat and bone meal are the best organic additives that not only increase the yield of mushrooms, but also their quality. The study shows that the quality of mushrooms obtained in the second wave is significantly higher than the quality of mushrooms obtained in the previous wave. Positive is the fact that the use of organic waste in industrial mushroom production contributes to the efficient management of, as a rule, little used by-products of food and processing industries.
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