RESUMEN
Sulfate-reducing bacteria (SRB) play an important role in the sediments of bay areas, estuaries, and lakes. However, information regarding the genetic diversity of SRB in the sediments of drinking water reservoirs is scarce. In this study, we collected sediment samples from different sites in the Zhou Cun drinking water reservoir between April and June 2012. To explore the genetic diversity of SRB, we used the most-probable-number (MPN) method, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE), and a cloning approach. The average content of acid-volatile sulfide at the deepest sampling site was 205.87 µg/g sediment. This result is often associated with a large abundance of SRB in the associated sediment. The highest MPN estimate (1.15 x 10(5) cells/g sediment) was detected in May at the deepest sampling site. The PCR-DGGE fingerprints of SRB based on the dissimilatory sulfite reductase beta subunit (dsrB) gene varied according to the different sampling sites and dates. The highest abundance of SRB in the sediments was predominantly found at the deepest sampling sites, as expected from the acid-volatile sulfide content. The dominant species were Desulfobulbus sp, Desulfobacterium sp, and uncultured sulfate-reducing bacteria. Redundancy analysis revealed that organic matter and the concentrations of nitrogen and phosphorus in the sediments were significantly correlated with the diversity of SRB communities present. The results of this study provide a better understanding of the sulfate-reducing microbial species in the sediments of the Zhou Cun drinking water reservoir.
Asunto(s)
Variación Genética , Hidrogenosulfito Reductasa/genética , Sulfatos/metabolismo , Bacterias Reductoras del Azufre/genética , China , Agua Potable/química , Agua Potable/microbiología , Sedimentos Geológicos , Filogenia , ARN Ribosómico 16S/genética , Bacterias Reductoras del Azufre/metabolismoRESUMEN
Thirteen children between the ages of six months and six years with acute diarrheal syndrome were investigated for Small Bowel Transit Time (SBTT). The results were compared with another study made by our section in which eleven children were studied; seven with chronic non-specific diarrhea and four controls. All the subjects had a double lumen catheter positioned in the small intestine with ports located 1 meter apart. A bolus of 4% P.E.G. was delivered into the stomach and the rate of appearance was monitored at the two collecting ports. Four normal children had a small bowel transit time of 60 min/m; one subject with shigella revealed a small bowel transit time of 30 min. Eight children with acute non-specific diarrhea had a mean of 90. Seven with chronic non-specific diarrhea had a mean of 99 min/m. Four patients with serotype positive E. coli had a mean of 83. In each case where SBTT was delayed there was also an increase in luminal free bile acids. In conclusion, diarrheal syndrome in children may present accelerated or delayed SBTT according to the etiology of each. Children with diarrheal syndrome showed an abnormal bile acid pattern in the duodenum which may represent a bacterial overgrowth and introduce a pathogenic role in the disease.
Asunto(s)
Ácidos y Sales Biliares/metabolismo , Diarrea Infantil/fisiopatología , Duodeno/fisiopatología , Infecciones por Escherichia coli/fisiopatología , Motilidad Gastrointestinal , Ácidos y Sales Biliares/análisis , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Factores de TiempoRESUMEN
Eight patients with inflammation of the skin about the cutaneous stoma responded to local application of a 20% cholestyramine ointment in a short period of time. Two children treated with the hydrophilic base (Aquaphor) alone did not respond to treatment. The ileal bile acid patterns of two children with ileostomies were found to be different from that of the control group. Ileostomy patients had a higher concentration for total bile acids and a higher percentage of free bile acids.