Molecular analysis of the pheromone and pheromone receptor genes of Ustilago hordei.

Cell-cell signaling is an integral part of the sexual and disease cycles of the smut fungi, which must mate to be pathogenic. This study reports the cloning and characterization of the pheromone genes Uhmfa1 and Uhmfa2 from MAT-1 and MAT-2 mating types of U. hordei, respectively, and the pheromone receptor gene Uhpra2 from MAT-2 cells. Similar to other fungal pheromone genes, Uhmfa1 and Uhmfa2 encode precursor peptides. Uhpra2 encodes a protein with sequence similarity to the 7-transmembrane class of G-protein coupled receptors. Deletion of Uhmfa1 and Uhpra1, and their subsequent replacement, confirmed the role of these genes in initiation of the sexual cycle. Uhmfa1 and Uhmfa2 were differentially expressed in various cell types and when opposite mating-type cells were grown together. The predicted mature pheromones of each mating type were synthesized, and each specifically induced conjugation tube formation in cells of the opposite mating type.

Characterization of a Vascular Wilt of Erythroxylum coca Caused by Fusarium oxysporum f. sp. erythroxyli Forma Specialis Nova.

A new forma specialis of Fusarium oxysporum (F. oxysporum f. sp. erythroxyli) pathogenic to Erythroxylum coca and E. novogranatense is described. The pathogen was isolated from the vascular tissue of diseased plants from an Erythroxylum plantation in Hawaii. This pathogen causes vascular wilt symptoms and death in both E. coca and E. novogranatense plants as soon as 7 weeks after soil infestation. The pathogenicity of seven isolates from the affected field was determined in field and growth-chamber studies. Genetic variation was not detected among the seven Hawaiian isolates, using arbitrarily primed polymerase chain reaction. The seven isolates could be differentiated from a strain isolated from a diseased E. coca plant from South America. All Hawaiian isolates and the South American isolate belonged to a single vegetative compatibility group.

Endophytic taxol-producing fungi from bald cypress, Taxodium distichum.

Pestalotiopsis microspora occurs as a range of strains in bald cypress, Taxodium distichum. The organisms live as endophytes in the bark, phloem and xylem, and isolates show differences in cultural and microscopic characteristics on common laboratory media. Many of these fungi make taxol as determined by the reactivity of partially purified culture extracts with specific monoclonal antibodies against taxol. In the case of one strain of P. microspora (CP-4), taxol was isolated from culture medium and was shown to be identical to authentic taxol by chromatographic and spectroscopic means.

Gluconeogenesis from propionate produced in the colon of the horse.

The production of propionate has been measured in the large colon of two ponies fitted with cannulas and fed on a standard diet of hay or hay and wheat bran. A continuous infusion of 14C-labelled sodium propionate was made into a cannula in the right ventral colon and samples of ingesta were obtained from another cannula near the end of the right dorsal colon. A simultaneous intravenous infusion of [2-3H]-labelled glucose was made to measure total glucose entry. Colonic propionate production on the hay diet was 146 (range 110-176) mg/h per kg body weight and, on the hay and bran, 195 (range 130-273) mg/h per kg body weight. Mean total glucose production for the two diets was 120 (range 98-143) and 92 (range 79-116) mg/h per kg body weight, respectively. The results obtained indicate that 50% of the glucose was synthesized from propionate produced in the colon in ponies on the hay diet and 61% in ponies on the hay and bran diet.

Cortisol in pregnancy toxaemia of sheep.

Of 31 pregnant ewes with clinical signs of pregnancy toxaemia, 24 had hypoglycaemia and hyperketonaemia at the time that a single blood sample was obtained. Twenty-five of these had a plasma cortisol concentration in excess of 10 ng/ml and six had a value below this. All the seven animals which did not show both hypoglycaemia and hyperketonaemia had a plasma cortisol concentration in excess of 10 ng/ml. Taking all the sheep together, 80% had a high plasma cortisol concentration. This could be the consequence of increased adrenal output or reduced excretion by the liver.

An enzyme-linked immunoassay for the measurement of the concentration of cortisol in sheep plasma.

An enzyme-linked immunoassay has been adapted for the assay of cortisol in sheep plasma. The results are similar to those obtained by radioimmunoassay but an enzyme-linked immunoassay does not require the use of radioactive compounds or expensive equipment to measure radioactivity.

Liquid flow and capacity of the caecum and colon of the horse.

The rate of flow of fluid from the caecum and from the large colon was measured in four Shetland-type ponies fed a hay diet. In two ponies with cannulas in the caecum and at the origin of the right ventral colon, a continuous intracaecal infusion of a solution of chromium EDTA was used and samples were obtained from the cannula at the origin of the right ventral colon. Based on four determinations, the liquid flow from the caecum was 54.2 +/- 1.89 litres d-1. In the other two ponies with cannulas in the origin of the right ventral colon and near the end of the right dorsal colon, a continuous infusion of chromium EDTA was made into the right ventral colon and samples were obtained from the right dorsal colon. The flow rate towards the end of the dorsal colon was 49.4 +/- 1.25 litres d-1, based on four determinations. The capacities of the caecum and large colon after death were 7.0 +/- 0.8 and 17.7 +/- 3.7 litres, respectively.

Further studies on the diagnostic value of gamma-glutamyl transpeptidase and 5'-nucleotidase in cattle, sheep and horses.

The distribution of 5'-nucleotidase (5'-NT) and gamma-glutamyl transpeptidase (gamma-GT) is similar in the tissues of the sheep, calf and horse, except that there is relatively less gamma-GT in calf liver than in the liver of the other two species. The liver lesion produced by the oral administration of chloroform is similar in the three species and is accompanied by the release of 5'-NT into the plasma of the sheep and calf but not of the horse. Conversely, gamma-GT is released into plasma of the horse but not of the sheep or calf. This difference is not related to the tissue distribution of the two enzymes. The kidney lesion in sheep produced by the intravenous administration of mercuric chloride is accompanied by a reduction in the rate of excretion of an injected dose of inulin and by an increase in the concentration of urea in plasma and in the activity of gamma-GT in plasma and urine. There was no increase in 5'-NT activity in plasma or urine.

The activity of diagnostic enzymes and the concentration of lipids in the blood vessels of cattle.

Blood vessel walls are shown to contain creatine phosphokinase, lactate dehydrogenase, gamma glutamyl transpeptidase and aspartate transaminase activity. The activity of these enzymes in the serum may be enhanced by leakage from damaged blood vessels. The activity of the enzymes alanine transaminase and alkaline phosphatase as well as the content of triglycerides, cholesterol and lipoproteins are very low in the vascular tissue and are unlikely to be of diagnostic value in vascular tissue injury.

The effect of induced liver, kidney and lung lesions on the toxicity of levamisole and diazinon in calves.

Liver damage in calves, produced by the oral administration of the flukecide, carbon tetrachloride, increased the toxic effect of diazinon but not of levamisole, whereas the presence of a renal tubular lesion caused by mercuric chloride enhanced the toxicity of both commonly used anthelmintic compounds. The toxicity of diazinon was increased in calves with a lung lesion caused by oral dosing with tryptophan, an agent implicated in 'fog fever' of cattle.

Effect of pretreatment with hepatic microsomal enzyme inducers on the toxicity of diazinon in calves.

The pretreatment of calves with a single dose of 10 mg kg-1 dieldrin or 21 daily doses of 10 mg kg-1 phenobarbitone increased the toxicity of diazinon as reflected by the development of more severe clinical signs and greater depression in whole blood cholinesterase activity in the pretreated calves. Induction by dieldrin or phenobarbitone of the hepatic microsomal enzyme amidopyrine-N-demethylase was also accompanied by a concurrent rise in the liver carboxylesterase activity.

Distribution of 5'-nucleotidase in the tissues of sheep and the effect of kidney and liver lesions on the activity of the enzyme in plasma and urine.

The distribution of 5'-nucleotidase (5'-NT) activity in the tissues of the sheep differs from that of gamma glutamyl transferase (GGT). Nevertheless, both enzymes are released into the plasma of sheep which have been infected with Fasciola hepatica or in which the bile duct has been ligated. In a sheep dosed with sporidesmin, a fungal toxin which damages the biliary tract, there was an increase in GGT activity in the plasma and urine but no change in 5'-NT activity. Neither enzyme was released into the plasma or urine of sheep dosed with carbon tetrachloride. In sheep with renal tubular necrosis and hepatocellular necrosis caused by dosage with hexachlorobutadiene, both enzymes were released into the plasma, and GGT, but not 5'-NT activity was found in urine. In sheep with tubular necrosis of the kidney caused by the administration of mercuric chloride, GGT activity, but not 5'-NT, increased in the plasma and urine.