Bioemulsifier production by Microbacterium sp. strains isolated from mangrove and their application to remove cadmiun and zinc from hazardous industrial residue

The contamination of ecosystems with heavy metals is an important issue in current world and remediation technologies should be in according to environmental sustainability concept. Bioemulsifier are promising agents to be used in metal removal and could be effective to many applications in environmental industries. The aims of this work was screening the potential production of bioemulsifier by microorganisms isolated from an oil contaminated mangrove, and evaluate cadmium and zinc removal potential of those strains from a hazardous industrial residue. From that, bioemulsifier-producing bacteria were isolated from urban mangrove sediments. Four isolates were identified as Microbacterium sp by 16S rRNA analysis and were able to reduce up to 53.3 percent of culture medium surface tension (TS) when using glucose as carbon and energy source and 20.2 percent when sucrose was used. Suspensions containing bioemulsifier produced by Microbacterium sp. strains show to be able to remove cadmium and zinc from contaminated industrial residue, and its ability varied according carbon source. Significant differences in metal removal were observed by all strains depending on the carbon source. When glucose was used, Cd and Zn removal varied from 17 to 41 percent, and 14 to 68 percent, respectively. However, when sucrose was used it was observed only 4 to a maximum of 15 percent of Cd removal, and 4 to 17 percent of Zn removal. When the same tests were performed after ethanol precipitation, the results were different: the percentages of removal of Zn (7-27 percent) and Cd (14-32 percent) were higher from sucrose cultures. This is the first report of heavy metals removal by bioemulsifier from Microbacterium sp.

Removal of heavy metals from paint industry's wastewater using Leca as an available adsorbent

The ability of light expanded clay aggregate to remove Pb++ and Cd++ from paint industry's effluents was studied at different levels of adsorbent, contact time and pH in April 2008. For this purpose, Pb and Cd removal from paint industry effluents were studied in batch reactors. Pb and Cd measurements have been taken with non-flame atomic absorption techniques and test methods were adapted from 19 th edition of standard methods for the examination of water and wastewater. In this study, different amounts of Leca [1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 g/L] were investigated. The amount of adsorbed Pb [II] and Cd [II] exposure to Leca increased from 1.41 to 3 mg/g and 0.22 to 0.75 mg/g, respectively. The maximum removal efficiency for Pb was 93.75% at pH = 7 and exposure to 10 g/L of Leca, while for Cd, it was nearly 89.7% at the same condition. In this study, adsorption process of lead and cadmium was fitted with Freundlich adsorption isotherm [R2Pb = 0.97 and R2Cd = 0.98]. The sufficient contact time was deemed 1-2 h for Cd and Pb. According to the results, Leca is recommended as a low cost and available adsorbent to remove lead and cadmium from industrial wastewater

Genotipificación de aislados clínicos de Helicobacter pylori en base a genes asociados a virulencia cagA, vacA y babA2: Primer aislamiento de una cepa babA2 positiva en pacientes chilenos / Genotypying of clinical isolates of Helicobacter pylori by cagA, vacA and babA2 virulence associated genes: First detection of a babA2 positive strain in Chilean patients

Background: Helicobacter pylori-associated gastroduodenal diseases depends on host characteristics, environmental conditions and bacterial virulence factors, such as cagA, vacA y babA2 gene products. Moreover, peptic ulcer disease has been related with cagA+, vacAs1m1 strains, while metaplasia and gastric cancer has been associated to cagA+, vacAs1 and babA2+ H pylori strains. Gene babA2 has not yet been described in clinical isolates from Chilean patients. Aim: To investigate the presence of cagA, vacA (s and m) and babA2 genes in clinical isolates of H pylori from Chilean patients. Material and Methods: Sixty six isolates from 41 patients were genotyped by PCR, using primers for s1a, s1b, s2, m1, m2, cagA and babA2 genes as previously described. Results: cagA gene was detected in 16 isolates (24.2 percent) while vacAs1a, vacAs1b, vacAs2, vacAm1 and vacAm2 were detected in 28 (42.4 percent), 14 (21.2 percent), 17 (25.8 percent), 21 (31.8 percent) and 29 isolates (43.9 percent), respectively. One isolate (1.5 percent) was babA2 positive, being the first isolate with this genotype described in Chile. Besides the babA2+ genotype this clinical isolate also presented cagA+ and vacAs1a which has been related with metaplasia or gastric cancer. Five isolates showed an ulcerogenic profile cagA+, vacAs1m1. Conclusions: The results presented indicate the prevalence of vacAs1m1 genotype among the clinical isolates analyzed, and a low frequency of babA2 genotype.

Evaluación de los niveles de la adhesina P1 en fimbrias de Streptococcus mutans aisladas de pacientes susceptibles y resistentes a la caries dental / Evaluation of P1 adhesin levels in Streptococcus mutans fimbriae isolated from caries susceptible and caries resistant patients

El objetivo de este trabajo fue la determinación de los niveles de P1 en fimbrias aisladas de S. mutans, provenientes de pacientes susceptibles (CS) y resistentes (CR) a la caries dental. El análisis electroforético de las preparaciones demostró la existencia de 5 bandas mayores migrando a 200, 175, 157, 86 y 66 kDa, tanto en los CR como en los CS. La inmunotransferencia indicó la presencia de las mismas 5 bandas, que fueron reconocidas por el antisuero antifimbria S. mutans. Adicionalmente, la banda de 175 kDa fue reconocida por el anticuerpo anti-P1. El análisis de la inmunotransferencia demostró que los niveles de componentes reactivos con las fimbrias y P1 fueron mayores en los sujetos CS que en los CR. Estos resultados sugieren que las diferencias existentes en la composición de las fimbrias de S. mutans de CS y CR pueden jugar un papel importante en la virulencia de este microorganismo en la caries dental.

Frequency of pap and pil operons in Escherichia coli strains associated with urinary infections

Strains of E. coli isolated from patients with urinary tract infection were examined for P and type 1 adhesin production by colony hybridization with pap and pil operons. The P pili probe detected 45 (46.4 per cent) of the total of 97 strains studied and the type 1 pili probe detected 83 (85.6 per cent). The pap operon was detected in 39 (53.4 per cent) of 73 strains isolated from urine of patients with urinary disease and in 6 (25.0 per cent) of 24 strains isolated from feces of healthy individuals employed as controls (P = 0.029), and the pil operon was detected in 67 (91.8 per cent) of the urinary strains and in 16 (66.6 per cent) of the fecal strains (P = 0.007). Our data did not show significant differences in frequency of P pili among isolates from pyelonephritis (78.5 per cent), cystitis (45.8 per cent) and asymptomatic bacteriuria (54.5 per cent). Type 1 pili were not associated with the different types of infection; the frequency of these pili was 100 per cent in pyelonephritis and in asymptomatic bacteriuria, and 87.5 per cent in cystitis. The incidence of pap operon in strains isolated from pyelonephritis and from asymptomatic bacteriuria was higher in 11-to 40-year old women. These data show a high frequency of pap and pil operons among uropathogenic strains of E. coli, which seems to be an important factor in the development of urinary infection.