Interactions of cultured endothelial cells with TGF-beta, bFGF, PDGF and IGF-I

Endothelial cells in culture synthesize the growth factors transforming growth factor beta (TGF-beta), basic fibroblast growth factor (bFGF), platelet derived growth factor (PDGF) and, perhaps, insulin like growth factor I (IGF-I). We have previously demonstrated that IGF-I and PDGF have both high affinity receptors and stimulate glucose and AIB uptake in the microvessel cells under study and that IGF-I, but not PDGF, has similar high affinity receptors in cultured large vessel endothelial cells. In the present study, cultured bovine endothelial cells were exposed to these four growth factors to determine a) their effects on the acute metabolic processes of neutral amino acid (AIB) and glucose uptake and b) their interactions at the endothelial cell surface. In microvessel endothelial cells, each growth factor stimulated AIB and glucose uptake 2-4 fold whereas in large vessel endothelial cells only bFGF stimulated glucose uptake. Each growth factor had specific high affinity binding to the microvessel cells that was not influenced by the presence of the other growth factors. In large vessel endothelial cells, similar high affinity binding was present only for IGF-I and to a lesser degree TGF-beta. When cells were exposed to a given growth factor for 18 hours, homologous receptor downregulation was observed, with a maximal 60-95% decrease in surface binding. These findings suggest several potential levels of interaction of the growth factors TGF-beta, bFGF, PDGF and IGF-I in cultured vascular endothelial cells.     

Fruiting at High Temperature and Its Genetic Control in the Basidiomycete Flammulina velutipes

Of 10 geographic strains of Flammulina velutipes, 4 were found capable of fruiting at 22°C (Fr_H) rather than at the typical 15°C (Fr_L). Crosses made between Fr_H and Fr_L monokaryons were never observed to fruit at 22°C. However, some hybrids did fruit at the intermediate temperature of 18°C when grown on appropriate substrates, indicating incomplete dominance of the low-temperature requirement. Analysis of progeny of five Fr_H × Fr_L crosses indicated that a minimum of two genes appears to control the requirement for fruiting at ≤15°C. The genes are not closely linked to either incompatibility locus.     

Initial stages in the course of adventitious bud formation on embryos of Picea abies

Adventitious buds on embryos of Picea abies (L.) Karst. developed after a pulse treatment with 250 μ M benzyladenine (BA) of pH 5.5 for 2 h. Light and temperature regimes were not critical during the initial stages. Adventitious buds developed faster after a pulse treatment and the variation among different experiments was lower compared to when the embryos were cultured on media supplemented with BA. Various stages of the differentiation of adventitious buds were identified: stage 1 - appearance of meristematic centres (approximately the first two weeks); stage 2 - development of adventitious bud primordia (approximately the third week); stage 3 - adventitious bud development (from approximately the 4th to the 8th week). This system may be used for further studies on bud differentiation.     

Initiation and development of wound tissue and roots on hypocotyl cuttings of Pinus sylvestris in vitro

The rooting of hypocotyl cuttings from 20-day-old seedlings of Pinus sylvestris L. cultured in vitro is discussed. About 40% of the cuttings cultured on medium lacking activated charcoal produced roots during the first two months. When activated charcoal was added to the medium, either root formation (75% formed roots) or wound tissue growth (95% formed large wound tissues) was stimulated in different experiments. These large wound tissues did not develop any roots. The anatomical changes in the basal part of the cuttings were similar during the first two weeks in all the cuttings studied. A vascular cylinder composed of short tracheids with many pores developed. Thereafter the differentiation process became varied. The amount of wound tissue produced and the time for rooting differed among the cuttings. Tracheid nests which were in contact with the vascular system in the hypocotyl via short tracheids were observed after three weeks. Subsequently, roots developed from the tracheid nests. The longer root formation was delayed, the larger the wound tissue became.
Short tracheids were found close to the wound tissue surface. Their ability to adsorb nutrients and water is discussed.     

Transient enhancement of serum somatomedin levels prior to weaning of growth-impaired vasopressin-deficient Brattleboro rats

Somatomedin serum levels of congenitally vasopressin-deficient Brattleboro rats were determined postnatally between day 1 and 55, and compared with heterozygous control values. Assays were performed with a radioimmunoassay of insulin-like growth factor 1 (IGF-1). A transient enhancement of immunoreactive IGF-1 levels between day 8 and 21 of age and a reduction in adulthood was found. This observation shows that the early growth impairments of the Brattleboro mutant are not due to a deficiency of IGF-1.     

Separation of isoenzymatic forms of human serum galactosyltransferase by chromatofocusing and isoelectric focusing. Application to cancerology

Chromatofocusing is used to separate the multiple isoenzyme forms of human serum galactosyltransferase. At least 11 major peaks of activity are observed in normal sera, which are eluted between pH 4.3 and 6.9; a fraction of activity is eluted above pH 7.0. The normal patterns are compared with those obtained with sera from cancer patients and with an ascitic fluid. Chromatofocusing appears as resolutive as agarose isoelectric focusing.     

Antibodies to spiroperidol and their anti-idiotypes as probes for studying dopamine receptors

Spiroperidol was covalently conjugated to bovine serum albumin (BSA). Conjugated spiroperidol was almost as efficient as free spiroperidol in its binding capacity to dopamine receptor. Antibodies to spiroperidol were produced in rabbits following repeated immunizations with the conjugate of spiroperidol and BSA. The obtained antibodies have an apparent K_D of 0.02 nM for [³H]-spiroperidol. These antibodies bind also to other butyrophenones with IC₅₀ values three to four orders of magnitude higher than the IC₅₀ obtained with unlabeled spiroperidol. Antibodies were purified from anti-spiroperidol sera by affinity chromatography. Anti-idiotypic antibodies were raised in rabbits by immunization with the purified anti-spiroperidol antibodies. Some rabbits produced anti-idiotypic antibodies which bind to rat and calf striatum.     

Monoclonal antibodies modify acetylcholine-induced ionic channel properties in cultured chick myoballs

Summary Monoclonal antibodies directed against the cholinergic binding site of the acetylcholine receptor were found to alter the ion channel properties in cultured chick myoballs. Time and dose dependent reduction in acetylcholine sensitivity was observed. Noise analysis experiments indicated a decrease in the mean single channel conductance and an increase in the mean single channel open time.     

Mass rearing,distribution and colonization ofPteroptrix smithi (Compere) in Israel

Pteroptrix smithi (Compere) is a gregarious internal parasite of the diaspine scaleChrysomphalus aonidum. During the last few years, both host and parasite were mass reared in the laboratory on squash fruits. Releases were made in scaleinfested citrus orchards that were not reached by the parasite’s natural spread. Parasites were recovered from many of the release sites.