Exclusion of the phosphoinositide-specific phospholipase Cβ3 (PLCB3) gene as a candidate for multiple endocrine neoplasia type 1

The predisposing genetic defect in multiple endocrine neoplasia type 1 has been assigned to chromosomal region 11q13. Our previous attempts to identify the MEN1 gene have resulted in the isolation of the phospholipase Cβ3 gene from the actual region. PLCB3 plays an important role in signal transduction and, moreover, shows loss of expression in some endocrine tumors, in accordance with a putative tumor suppressor gene function, and thus appears to be an excellent candidate for MEN1. We have therefore undertaken screening for constitutional mutations in individuals from MEN1 families. Several sequence alterations have been discovered, none of them however fulfilling the criteria for a disease-related mutation. We can now exclude PLCB3 from candidacy as the MEN1 gene. Received: 24 July 1996 / Revised: 16 August 1996     

Changes in pectinmethylesterase (PME) activity caused by ethylene applied at different temparatures

At 25?C the activity of pectinmethylesterase (PME) solutionincubated in ethylene atmosphere (100 µl/liter) was lowerthan that of PME solution incubated in air. On the other hand,at 6?C the activity of the ethylene-incubated PME was higherthan that of the air-incubated solution. The effects of bothtemparature and ethylene on PME-solution activity are reversiblephenomena. Ethylene accelerated both softening was acceleratedas PME activity in avocado fruit at 25?C. However at 6?C softeningwas accelerated as PME activity was promoted by ehtylene treatment.Ethylene had similar effects on PME activity in both purifiedenzyme solution and in vivo systems. (Received ; )     

Multiple forms of Vitis vinifera catechol oxidase

Grape catechol oxidase shows multiple forms upon ion exchange chromatography, acrylamide gel electrophoresis and gel filtration. Conversion of some bands into others, which occurs during isolation and storage, is enhanced by dilution and by treatment with urea or acid pH. Estimation of MWs suggested that the conversions might be due to dissociation of the enzyme into subunits, but attempts to induce reassociation were unsuccessful. The effects of urea and acid pH could be imitated by partial enzymic proteolysis of the enzyme. Analysis of the various bands observed in gel electrophoresis suggested that some of the enzyme forms have the same MWs but differ in charge distribution.     

Germination, Growth, and Sporulation of Bacillus thuringiensis subsp. israelensis in Excreted Food Vacuoles of the Protozoan Tetrahymena pyriformis

Spores of Bacillus thuringiensis subsp. israelensis and their toxic crystals are bioencapsulated in the protozoan Tetrahymena pyriformis, in which the toxin remains stable. Each T. pyriformis cell concentrates the spores and crystals in its food vacuoles, thus delivering them to mosquito larvae, which rapidly die. Vacuoles containing undigested material are later excreted from the cells. The fate of spores and toxin inside the food vacuoles was determined at various times after excretion by phase-contrast and electron microscopy as well as by viable-cell counting. Excreted food vacuoles gradually aggregated, and vegetative growth of B. thuringiensis subsp. israelensis was observed after 7 h as filaments that stemmed from the aggregates. The outgrown cells sporulated between 27 and 42 h. The spore multiplication values in this system are low compared to those obtained in carcasses of B. thuringiensis subsp. israelensis-killed larvae and pupae, but this bioencapsulation represents a new possible mode of B. thuringiensis subsp. israelensis recycling in nontarget organisms.     

Δ9-Tetrahydrocannabinol: Depression of ventilatory regulation; Other respiratory and cardiovascular effects

Δ⁹-Tetrahydrocannabinol, administered intravenously in doses of 1.0, 0.5 and 0.25 mg/kg, caused marked decrease of ventilatory response to carbon dioxide in anesthetized dogs. The drug also resulted in mild decrease of total pulmonary resistance, in marked bradycardia and in transient arterial hypotension. These results clearly demonstrate that marijuana can cause depression in the regulation of ventilation.     

DIFFUSION BOUNDARY LAYER TRANSPORT IN GRACILARIA CONFERTA (RHODOPHYTA)1

A theoretical framework on the combined effect of water velocity and solute concentration on the photosynthetic performance of the red alga Gracilaria conferta (Rhodophyta) is developed. This is based on the balance between the rate of transport through boundary layers and Michaelis-Menten-type equations for carbon consumption and for production of oxygen and hydroxyl ions. By comparing the theoretical models with experimental data, we found that the mechanism of enhancing photosynthetic rates by increasing water velocity cannot be attributed to enhanced bicarbonate and CO₂ transport, nor to CO₂ as a sole source of carbon. Velocity-facilitated photosynthesis may be due to the enhanced removal of OH^? ions, which inhibit photosynthesis when accumulated on the algal surface. Oxygen had no inhibitory effect on Gracilaria conferta.     

Copper content and amino acid composition of catechol oxidase from clairette grapes

Catechol oxidase was purified 330 × from chloroplasts of Clairette grapes. The MW of the enzyme is 80 000 and its Cu content is half an atom per molecule. The amino acid composition of the enzyme is also described.