Microcystins are secondary metabolites produced by several freshwater, bloom-forming cyanobacterial species. Microcystin-producing cyanobacteria co-occur with a complex community of heterotrophic bacteria. Though conflicting, studies suggest that microcystins affect the physiology of heterotrophic bacteria by inducing oxidative stress and increasing cell envelope permeability. Based on these ob...

More than 400 achlorophyllous plant species in 87 genera are parasitic upon fungi, and exploit them as their principle source of carbon. With a few exceptions, most of these myco-heterotrophic plants are now thought to be 'cheats', stealing carbon and nutrients from the mycorrhizal associates of adjacent autotrophic plants. Most myco-heterotrophs are therefore considered to be epiparasitic on g...

Our survey of cooling tower water demonstrated that the highest density of legionellae, >/=10 CFU/100 ml, appeared in water containing protozoa, >/=10 MPN/100 ml, and heterotrophic bacteria, >/=10 CFU/100 ml, at water temperatures between 25 and 35 degrees C. Viable counts of legionellae were detected even in the winter samples, and propagation, up to 10 CFU/100 ml, occurs in summer. The counts...

Although reduced inorganic sulfur compound (RISC) oxidation in many chemolithoautotrophic sulfur oxidizers has been investigated in recent years, there is little information about RISC oxidation in heterotrophic acidophiles. In this study, Acidicaldus sp. strain DX-1, a heterotrophic sulfur-oxidizing acidophile, was isolated. Its genome was sequenced and then used for comparative genomics. Furt...

BACKGROUND The high numbers of heterotrophic microorganisms that have been cultured from dental unit waterlines (DUWs) have raised concern that this water may exceed suggested limits for heterotrophic plate counts (HPCs). The main purpose of this investigation was to examine HPC variability in DUWs and to examine in detail the effect of laboratory processing of water samples on HPC values. ME...

Biogeochemical implications of global imbalance between the rates of marine dinitrogen (N2) fixation and denitrification have spurred us to understand the former process in the Arabian Sea, which contributes considerably to the global nitrogen budget. Heterotrophic bacteria have gained recent appreciation for their major role in marine N budget by fixing a significant amount of N2. Accordingly,...

Heterotrophic nanoplankton flagellates and bacteria were quantified at regular intervals during a month in Limfjorden, Denmark. The number of flagellates averaged about 103 ml-l and ranged from < 2 X 102 to about 3 X 103 ml-l. The composition of this fauna was dominated by choanoflagellates, non-plgmented chrysomonads and bicoecids; other forms are rarer. A substantial part of this fauna is ass...

The pelagic ocean harbors one of the largest ecosystems on Earth. It is responsible for approximately half of global primary production, sustains worldwide fisheries, and plays an important role in the global carbon cycle. Ocean warming caused by anthropogenic climate change is already starting to impact the marine biota, with possible consequences for ocean productivity and ecosystem services....