Effects of Polychlorinated Biphenyls on Growth and Respiration of Heterotrophic Marine Bacteria

Abstract

A number of marine bacterial isolates from both near-shore and open-ocean environments were tested for growth inhibition with exposure to low concentrations (1 to 100 ,ug/liter) of Aroclor 1254, a commercial mixture of polychlorinated biphenyls (PCBs). Of over 17 bacterial cultures tested, growth of only two openocean isolates, one a pseudomonad and the other a tetrad-forming coccus, was consistently inhibited by Aroclor at concentrations as low as 10 ,ug/liter (10 ppb). Growth inhibition was dose dependent over a concentration range of 10 to 100

Effects of Polychlorinated Biphenyls on Macromolecular Synthesis by a Heterotrophic Marine Bacterium

“…By 4 h posttreatment, RNA/protein, DNA/protein, and DNA/RNA ratios were similar in the total cell fraction from an untreated control culture and one in which growth was completely inhibited. Furthermore, cells whose growth was stopped by PCBs grew at normal rates without a lag when transferred to PCBfree medium (1). These findings indicated that Aroclor-treated cells did not selectively degrade their nucleic acids or proteins during the period their growth was arrested.…”

“…In this medium without Aroclor it grew in chains of from 2 to 10 cells, and, with 10 to 50,g of PCBs per liter present, it grew in long filaments. In seawater-Casamino Acids-yeast extract medium (SWCAA) (1), it grew as single, motile cells in the absence of PCBs and in short chains of cells when Aroclor was present at 10 to 100 ,tg/liter. SWCAA medium was developed in response to the need for accurate estimates of cell numbers in the work to be described.…”

“…(vol/vol), a level at which no effects on cell growth, morphology, or physiology could be detected. Aroclor 1254, methods of handling it, and methods of cleaning culture glassware have been described (1).…”

“…It was previously reported that Aroclor 1254, a mixture of isomers of polychlorinated biphenyls (PCBs), when added to cultures at a concentration of 10 to 100 ,ug/liter (ppb), inhibited growth of two marine heterotrophic bacterial isolates but did not impair, on a per-cell basis, their ability to take up and oxidize amino acids or carbohydrates tested (1). With 10 Ag of Aroclor per liter in the medium, cells of one of these, a pseudomonad, had subnormal carotenoid levels and grew with altered, filamentous morphology.…”

Influence of PCBs on the predator-prey relation between bacteria and protozoa in soil

“…More ecological approaches were conducted on marine or fresh water with bacteria [3], algae [4] and protozoa [5,6]. The last authors tested the response of indigenous protozoan communities to complex river effluent supply: they observed the colonization of artificial substrates supplemented or not by the effluents by the protozoa in laboratory microecosystems and then, they validated the laboratory predictions using similar sampling methods in the field.…”