Four species of harbour porpoise (Phocoena phocoena) and one herring (Clupea harengus) sample from the southern Baltic Sea were analysed in an attempt to study the concentration and biomagnification of 17 chlordane related compounds (CHLs) including 12 components present in technical chlordane, the toxic metabolites oxychlordane and cis-hepatchlorepoxide and the photoconversion products photoheptachlor and two photo-cis-chlordanes. The concentration and biomagnification ability of CHLs were also compared to other organochlorines such as HCHs (hexachlorocyclohexanes), hexachlorobenzene, DDTs, dieldrin, mirex and PCBs (polychlorinated biphenyls). Of the CHLs analysed, 16 were detected in porpoise and 15 in herring including the photoconversion products. In both species the highest concentrations were found for PCBs and DDTs. The concentration of PCBs and CHLs in porpoise varied from 5700-16,000 and 470-1250 ng/g lipid, and in herring from 1300 and 49 ng/g lipid, respectively. The biomagnification factor (BMF: concentration in organism/concentration in food; all lipid normalized) in porpoise was found to be high for CHLs followed by dieldrin and lowest for HCHs. Among the CHLs, a big variation of BMF (BMF range approximately 1-50) was found e.g., the nonachlorinated compounds biomagnified to the highest degree followed by cis-heptachlorepoxide, photoheptachlor and oxychlordane.

Animals↗

PubMedDate not supplied

Cell segregation and lysis have profound effects on the growth of Escherichia coli in high cell density fed batch cultures.

Cell segregation into nondividing states and lysis was found to dominate the growth behavior of high cell density fed batch cultures of Escherichia coli. When the specific growth rate declined below a critical value, the biomass production, oxygen consumption, and carbon dioxide formation rates declined sharply. Concomitantly, an extensive loss of colony-forming ability (cfu) and accumulation of extracellular proteins was observed. A segregated model that considered different physiological states, including dividing, nondividing, and lysed cells, was developed and applied to experimental data from high cell density cultures of E. coli.

Bacterial Proteins↗