Levels of five mycotoxins in grains harvested in Atlantic Canada as measured by high performance liquid chromatography.

An analytical protocol using high performance liquid chromatography (HPLC) was used to analyze samples of spring wheat, winter wheat, 2-row barley, and 6-row barley over a period of three years for the presence of five mycotoxins. These included deoxynivalenol, zearalenone, T-2 toxin, HT-2 toxin, and diacetoxyscirpenol. The protocol employed a single extraction step using acetonitrile-water and two cleanup procedures.

Cadmium transport, resistance, and toxicity in bacteria, algae, and fungi.

Cadmium is an important environmental pollutant and a potent toxicant to bacteria, algae, and fungi. Mechanisms of Cd toxicity and resistance are variable, depending on the organism. It is very clear that the form of the metal and the environment it is studied in, play an important role in how Cd exerts its effect and how the organism(s) responds.

THE INHERITANCE OF COURTSHIP BEHAVIOR AND ITS ROLE AS A REPRODUCTIVE ISOLATING MECHANISM IN TWO SPECIES OF SCHIZOCOSA WOLF SPIDERS (ARANEAE; LYCOSIDAE).

The courtship behaviors of two morphologically similar spider species, Schizocosa ocreata and S. rovneri, are distinctive and prevent interbreeding. We used "forced" copulation between these species to investigate the mode of inheritance of the courtship behavior and to determine whether postmating isolating mechanisms exist.

The development of tolerance to antilipolytic agents by isolated rat adipocytes.

Using an isolated rat epididymal adipocyte system we have studied the development of tolerance to and cross-tolerance between nicotinic acid, 5-methylpyrazole-3-carboxylic acid and pyridyl-3-tetrazole. Preincubating isolated adipocytes with any one of these compounds results in a reduction of the antilipolytic activity of that compound when the cells are exposed to a subsequent challenge dose. Furthermore, preincubation with nicotinic acid, 5-methylpyrazole-3-carboxylic acid or pyridyl-3-tetrazole results in a reduction of the antilipolytic response to challenge with either of the other two compounds.

The development of tolerance to antilipolytic agents in rats.

The development of tolerance to the action of certain antilipolytic agents has been investigated in vivo in rats. Tolerance to oral nicotinic acid developed during twice daily dosing for 4 days at 100 and 250 mg/kg but not at 10, 25 or 50 mg/kg. Tolerance induced by high doses of nicotinic acid was no longer detectable after a further week without treatment.

Stimulation of flux through hepatic pyruvate dehydrogenase by 3-mercaptopicolinate.

Isolated hepatocytes from 24-h-starved rats were used to assess the possible effect of the hypoglycaemic agent 3-mercaptopicolinate on flux through the hepatic pyruvate dehydrogenase complex. Increasing the extracellular pyruvate concentration from 1 mM to 2 mM or 5 mM resulted in an increase in flux through pyruvate dehydrogenase and the tricarboxylic acid cycle as measured by 14CO2 evolution from [1-14C]pyruvate and [3-14C]pyruvate. Gluconeogenesis was inhibited by 3-mercaptopicolinate from both 1 mM and 2 mM pyruvate, but significant increases in malate and citrate concentrations only occurred in cells incubated with 1 mM pyruvate.

Variation in the social grouping tendency of a communal web-building spider.

The orb web-building spider, Metepeira spinipes, from Mexico occurs solitarily and, more frequently, in aggregations of 5 to 150 or more individuals. Although communal, individuals maintain webs and retreats within the colony and capture their own prey. Group size and interindividual distance apparently vary in response to climate and availability of prey.

Effect of acetone on the toxicity of atrazine towards photosynthesis in Anabaena.

The effect of acetone on the toxicity of atrazine towards photosynthesis in the blue-green algae Anabaena inaequalis, A. variabilis and A. cylindrica was investigated.

The effect of nickel on the growth, photosynthesis, and nitrogenase activity of Anabaena inaequalis.

Anabaena inaequalis was sensitive to nickel ion in the order of decreasing sensitivity of growth, photosynthesis, and acetylene reduction. At a culture density of 9 x 10(4) cells per millilitre, growth after 12 days was completely inhibited by 0.125 ppm (microgram/mL) Ni2+.

Effect of mercuric ion on the growth, photosynthesis, and nitrogenase activity of Anabaena inaequalis.

Anabaena inaequalis was sensitive to mercuric ion (Hg2+) in the ppb (nanogram per milliliter) range. Growth was inhibited significantly at concentrations of metal ion as low as 2 ppb, and 100 ppb was required to inhibit photosynthesis and acetylene reduction. Low levels of Hg2+ stimulated acetylene reduction and photosynthesis.

Molecular and metabolic heterogeneity of liver glycogen.

On refeeding after starvation, the resynthesis of rabbit-liver glycogen proceeds inhomogeneously and over-produces material of low molecular weight. The fate of radioactivity incorporated into glycogen from D-glucose-14C can be explained if glycogen of high molecular weight is synthesised on a protein backbone. Confirmation of this view is given by the effect upon glycogen of reagents that break disulphide bonds; these cause loss of the polysaccharide of high molecular weight.

The influence of lysosomes on glycogen metabolism.

Lysosome-rich fractions were isolated from rat liver homogenates. In some fractions the lysosomes were separated from the contaminating mitchondria by the use of discontinuous Ficoll/sucrose gradients. Some glycogen was associated with lysosome fractions.