Ecological and health risk assessment of heavy metals: a case study of residential waste sites in Umuahia, South-East Nigeria.

This study assessed the human health hazards and ecological risks of heavy metals from waste sites in residential vicinity. The heavy metals analyzed were Cr, Pb, Cd, Ni, Cu, and Zn. A total of 40 soil samples were collected from waste sites in two residential estates located in the urban and suburb areas of Umuahia, Abia state.

Induced Acid-Tolerance Response Confers Limited Nisin Resistance on Listeria monocytogenes Scott A.

The presence of an inducible acid-tolerance response (ATR) in Listeria monocytogenes Scott A was established. Protection of cells with induced ATR against nisin-mediated inhibition and stress was also evaluated. ATR was induced in L.

Nisin dissipates the proton motive force of the obligate anaerobe Clostridium sporogenes PA 3679.

The influence of nisin on the proton motive force (delta p) generated by glucose-energized cells of the obligate putrefactive anaerobe Clostridium sporogenes PA 3679 was determined. The components of delta p, the transmembrane potential (delta psi) and the pH gradient (delta pH), were determined from the distributions of the lipophilic cation [3H]TPP+ ([3H]tetraphenylphosphonium bromide) and [14C]salicylic acid, respectively. The cells maintained a constant delta p of -111 mV, consisting of a delta pH of 0.

Differential Sensitivity of Clostridium botulinum Strains to Nisin is Not Biotype-Associated.

The sensitivities of proteolytic and nonproteolytic Clostridium botulinum strains to nisin and other bacteriocins were investigated. Although there were statistically different nisin sensitivities among vegetative cells from 18 C. botulinum strains, these differences were not biotype-associated.

Bacteriocin-mediated inhibition of Clostridium botulinum spores by lactic acid bacteria at refrigeration and abuse temperatures.

The bacteriocinogenicity of Lactococcus lactis ATCC 11454, Pediococcus pentosaceus ATCC 43200, P. pentosaceus ATCC 43201, Lactobacillus plantarum BN, L. plantarum LB592, L.