The Bay of Quinte, a Z-shaped embayment at the northeastern end of Lake Ontario, has a long history of eutrophication problems primarily manifested as spatially extensive algal blooms and predominance of toxic cyanobacteria. The purpose of this study was to identify the structural changes of the phytoplankton community induced by two environmental alterations: point-source phosphorus (P) loadin...

One hundred representative strains of Bacillus cereus were selected from a total collection of 372 B. cereus strains using two typing methods (RAPD and FT-IR) to investigate if emetic toxin-producing hazardous B. cereus strains possess characteristic growth and heat resistance profiles. The strains were classified into three groups: emetic toxin (cereulide)-producing strains (n=17), strains con...

Freshwater dinoflagellates may form dense blooms during winter in ice-covered lakes. Unlike their marine counterparts, freshwater dinoflagellates are rarely considered to be potential toxin producers. Here we tested whether the winter species Peridinium aciculiferum produces a toxin(s) and investigated the potential adaptive function of that toxin, i.e., predator defense or inhibition of compet...

Cyanobacteria are a potential threat to aquatic ecosystems and human health because of their ability produce cyanotoxins, such as microcystins (MCs). MCs regularly monitored in fresh waters, but rarely estuarine marine waters despite the possibility downstream export. Over period two years, we monthly analyzed intracellular (in phytoplankton) extracellular (dissolved water) at five stations alo...

Phytoplankton populations can display high levels of genetic diversity that, when reflected by phenotypic variability, may stabilize a species response to environmental changes. We studied the effects of increased temperature and CO(2) availability as predicted consequences of global change, on 16 genetically different isolates of the diatom Skeletonema marinoi from the Adriatic Sea and the Ska...

Coastal California is a dynamic upwelling region where nitrogen (N) and iron (Fe) can both limit productivity and influence biogeochemistry over different spatial and temporal scales. With global change, the flux of nitrate from upwelling is expected to increase over the next century, potentially driving additional oceanic regions toward Fe limitation. In this study we explored the effect of ch...

A temperate phage coding for constitutive hypertoxigenicity has been constructed in Vibrio cholerae strain 569B and used to lysogenise the low-toxin-producing strain MAK 757; 18% of lysogens showed 10-100-fold increase in toxin production. This property was also transmitted at low frequency to second generation lysogens. Thus temperate phage can increase toxin production in a low-toxin-producin...

background and objectives: infectious diarrhoeal diseases are great problem throughout the world and are responsible for considerable morbidity and mortality. shiga toxin-producing escherichia coli (stec) is a major cause of gastroenteritis that may be complicated by hemorrhagic colitis (hc) or the hemolytic uremic syndrome (hus), which is the main cause of acute renal failure in children. food...

The quality of drinking water may be significantly reduced by the presence of cyanobacteria capable of producing toxins, taste, and odor. Several different genera of cyanobacteria are capable of producing microcystin toxins. Moreover, toxin-producing cyanobacteria share specific ribosomal RNA (rRNA) sequences not found in non-toxin-producing strains. Consequently, an rRNA gene probe can be a us...