Stable symbiont communities persist in parents,gametes, and larvae of Montipora capitata across historical bleaching phenotypes

Coral Reefs - Parental effects on early life history stages of corals are poorly understood, but with severe environmental disturbances, these impacts may be increasingly important in understanding...     

Selective inhibition of flagellar activity in Chlamydomonas by nickel.

Flagellar activity in the biflagellate chlorophyte Chlamydomonas reinhardtii is selectively inhibited by Ni2+ or by treatment with Ca2+-chelating agents. Inhibitions of swimming speed, geotaxis, phototaxis, and pattern swimming result from qualitative and quantitative losses in the activity of individual flagella and in the coordination of activity between the 2 flagella of each cell. Addition of Ca2+ (a) prevents inhibition and (b) restores normal flagellar activity in inhibited cells. Mg2+ is partially effective in reversal of inhibition. Other ions do not cause similar inhibition or reversal of nickel inhibition. The characteristics of inhibition and reversal suggest that the primary target for nickel is a component of the flagellar apparatus, and that this component uses Ca2+ to perform its normal function in the regulation of flagellar activity. A 2nd target for nickel is a Ca-requiring process specific to phototaxis (and not involved in the photophobic response).     

Helper (OKT4) T cells from human T cell colonies produce potent colony-stimulating activity

Confluent T cell colonies were grown by culturing blood mononuclear cells in double agar layers containing autologous plasma and phytohemagglutinin (PHA) for one week (37 degrees C, 5% CO2). The plates were then overlaid with serum-free alpha medium which was harvested after 24 h. This medium was demonstrated to have colony-stimulating activity (CSA) of greater potency than conventionally prepared PHA-leukocyte conditioned medium, which was prepared by incubating cells from the same donors. Removal of OKT4-positive cells using a monoclonal antibody and complement abolished CSA production by cells from T cell colonies while the removal of OKT8-positive cells had no effect.     

Sensitive mRNA detection using unfixed tissue: combined radioactive and non-radioactive in situ hybridization histochemistry.

In the present study some experimental parameters for in situ hybridization histochemistry (ISHH) have been analysed using 35S-labelled and alkaline phosphatase-conjugated probes, in order to develop a reproducible double-labelling procedure. We have compared the total exclusion of tissue fixation with tissue sections fixed by immersion in formalin. In addition, the effect of dithiothreitol was assessed both when combining radiolabelled and non-radioactive probes on a single tissue section and when the probes were used separately. Hybridization of unfixed tissue resulted in stronger specific labelling and lower background both for radiolabelled and alkaline phosphatase-conjugated probes. No loss in tissue preservation was seen at the light microscopic level after hybridization of unfixed tissue. High concentrations (200 mM) of dithiothreitol strongly suppressed background when using 35S-labelled probes, whereas in the non-radioactive procedure, alkaline phosphatase labelling could only be achieved with very low dithiothreitol concentrations (less than 1 mM). This incompatibility led to a protocol using unfixed tissue sections and a sequential hybridization procedure, with the radiolabelled probe and high concentrations of dithiothreitol in the first step and the alkaline phosphatase-conjugated probe without dithiothreitol in the second step.     

Production of fumonisins B1, B2 and B3 byFusarium proliferatum Isolated from rye grains

Using the seed- plate technique, we have isolated a strain ofF. proliferatum from rye grains that produces 3 fumonisins, fumonisin B₁ (FB₁), FB₂ and FB₃ on inoculated rice and corn. Inoculated corn and rice were extracted with an aqueous methanol solution and fumonisin concentrations estimated using high performance liquid chromatography. Production of all 3 fumonisins (FB₁, FB₂ and FB₃) was much higher on rice than corn; ranging from 3816, 1068 and 985 ppm to 1643, 350 and 162 ppm respectively. We conclude that all natural substrates whereF. proliferatum is present as a component of the mycoflora should be monitored for the presence of fumonisins.     

Biosolubilization of low-rank coal by aTrametes versicolor siderophore-like product and other complexing agents

Summary A heat stable, low molecular weight (<1000) extracellular product inTrametes versicolor (=Coriolus versicolor=Polyporous versicolor) cultures was demonstrated to be a principal factor in the solubilization of leonardite and other low-rank coals. The solubilization of leonardite byT. versicolor cell-free cultures and active fractions was inhibited by Fe³⁺ and was mimicked by the siderophore desferal mesylate and the iron chelating agents EDTA and 8-hydroxyquinoline. Leonardite solubilization by these later compounds was also inhibited by Fe³⁺. The ferrated and unferrated form of the partially purified active component fromT. versicolor cultures demonstrated absorption spectra that were similar to the ferrated and unferrated form of desferal mesylate.