Mutagenic and membranal effect of a phytotoxic molecule isolated from olive leaves parasitized by the fungusCycloconium oleaginum Cast

A phytotoxic substance (C₂₃H₄₄O₃) which is named Substance A, was purified from olive leaves infected withCycloconium oleaginum Cast. The mutagenic effect of this substance was detected using TA 100 and TA 102 strains ofSalmonella in the Ames test usingBacillus subtilis strains M45 rec^–, H17 rec⁺ in the rec assay. Another substance manifesting the mutagenic effect was found in the extract from theCycloconium oleaginum culture. This substance was not detected in the extract from contaminated olive leaves. Substance A increased electrolytes leakage from tissue of olive leaves, thus manifesting its phytotoxicity.     

Analysis of stimulating products involved in primary and secondary allogenic proliferation in man

HLA-D typing, primed lymphocyte test (PLT), and DR (Ia-like) serology were compared in a population and family study. A significant positive correlation was observed between theHLA-D region products detected by these three techniques. The strongest correlation observed was between PLT and DR serology, indicating a very close functional similarity between PL and DRw antigens. The DRw antigens and/or PL products appear to be mainly responsible for secondary proliferation. Data are presented which suggest that DRw and/or PL products could be distinct from the Dw products, involved in primary MLR. Nevertheless, a DRw disparity associated with a Dw incompatability is able to increase the intensity of a primary MLR, suggesting that DRw antigens also influence a primary proliferative response.     

In vitro stimulation of prolactin release by vasoactive intestinal peptide

The effect of vasoactive intestinal peptide (VIP) on anterior pituitary hormone release was examined in a variety of in vitro preparations. Synthetic VIP was capable of stimulating increased prolactin (PRL) release from male rat hemipituitaries in doses as low as 10⁻⁹ M only when the enzyme inhibitor bacitracin was present in the incubation medium. Natural porcine VIP was similarly capable of stimulating PRL release, but only at higher doses (10⁻⁶ M). Additionally, synthetic VIP was capable of stimulating PRL release from dispersed anterior pituitary cells harvested from adult male and lactating female rats and from an enriched population of lactotrophs obtained by unit gravity sedimentation of similar dispersed cells from infantile female rats. No effect of VIP on luteinizing hormone, growth hormone or thyroid stimulating hormone release was seen. These findings taken in concert with the presence of VIP in the hypothalamus, pituitary and hypophyseal portal plasma of the rat suggest a physiological role for VIP in the control of PRL secretion.     

Spontaneous neurite outgrowth and vasoactive intestinal peptide-Iike immunoreactivity of cultures of human paraganglioma cells from the glomus jugulare

Summary The chief cells of paraganglionic tissues have morphological and functional similarities to adrenal chromaffin cells, and both cell types are derived from the neural crest. In the present investigation cells from two glomus jugulare paragangliomas were studied in culture. Approximately 50% of the cells from one tumor, and 7% from the other spontaneously formed neurite-like processes. Numerous granular and agranular synaptic-like vesicles also appeared in the process-forming cells. In contrast to findings with normal and neoplastic adrenal chromaffin cells, addition of nerve growth factor (NGF) to the culture medium had no major effects on proportion of cells with processes. Dexamethasone caused only a small decrease in process length. Culturing of the tumors also appeared to promote production of material with VIP-like immunoreactivity. It is concluded that the phenotype of paraganglioma as well as pheochromocytoma cells may be altered in vitro. Responsiveness to specific factors such as NGF or steroids, however, may vary for related tumor cell types in different anatomic locations.     

Segregation analysis in hereditary retinoblastoma

Summary Segregation analysis was performed on 211 nuclear families belonging to 166 pedigrees of hereditary retinoblastoma found in a number of series which have been gathered from the literature. Bilaterally affected carriers appear homogeneous. The segregation ratio in their offspring is 0.49, and the proportion of bilateral cases among affected offspring is 0.87. Both unilaterally affected and unaffected carriers appear heterogeneous. The very low segregation ratio (0.08) in the offspring of unilateral carriers who are not detected through an affected child, suggests the possiblity of two types of carriers, high and low transmitters. The proportions of low transmitters was estimated as 0.14 among all familial unilateral carriers and as 0.45 among all detected unaffected carriers. Unilateral and unaffected high transmitters give a significantly lower segregation ratio than bilaterally affected carriers.On the one hand, the existence of these two different types of carriers provides arguments in support of the hypothesis of delayed mutation. On the other hand, the differences in penetrance among high transmitters, according to their phenotype, supports the hypothesis of host resistance. Under the two-mutation hypothesis, the possibility that the mutation rate is variable among individuals and partly genetically determined, is suggested.     

Method for the determination of mean densitometric profiles of chromosomes

When comparing the densitometric profiles of corresponding chromosomes registered from different metaphases or homologous pairs, one is always faced with the variability of their length and overall height. This makes difficult the quantitative comparison of a given chromosome treated by various staining procedures. — A simple and rapid method has been developed for normalizing the densitometric profiles and averaging them in order to obtain a mean density pattern of each chromosome. The analysis involves: photographic images, digitalization of the densitometric profiles and processing of the data by a mini-computer. — The method, based on a linear relationship between the area of the densitometric profiles and their length, has been applied to five human chromosomes (1, 2, 6, 12 and 16) stained by ethidium bromide, quinacrine mustard (with or without acidic hydrolysis), pararosaniline and bisaminophenyl-oxadiazole (Feulgen reaction).     

Individual and combined toxicity of three heavy metals,Cu, Cd and Cr for the marine copepod Tisbe holothuriae

The acute toxicity of Cu, Cd and Cr to the marine copepod Tisbe holothuriae, Humes, was estimated by static bioassays and the LC _inf50 ^su48h (in mg/l) was calculated. Copper proved to be the most toxic (LC _inf50 ^su48h = 0,08 ± 0,01 mg/l) and chromium the least toxic (LC _inf50 ^su48h = 8,14 ± 0,05 mg/l), while cadmium showed an intermediate toxicity (LC _inf50 ^su48h = 0,97 ± 0,04 mg/l).In mixtures of the two metals an obvious synergism of the effects was observed in all cases. In all three combinations with two metals (Cu + Cd, Cu + Cr, and Cd + Cr) the mortality was higher than that expected on a purely additive basis. The mixture of the three metals presented a higher toxicity than that of the individual metals acting separately, but lower than that of all two metals mixture.     

Octopine Ti-plasmid deletion mutants of agrobacterium tumefaciens with emphasis on the right side of the T-region

One hundred and twelve Agrobacterium tumefaciens mutants with a deleted octopine Ti plasmid were isolated. They originated from four insertion mutants, each of which carried the transposon Tn904 at a different position in the Ti plasmid. The deletion mutants were selected on the basis of loss of the capacity encoded by the Ti plasmid to degrade octopine. They were tested for the expression of other Ti-plasmid coded functions: tumor induction, presence of lysopine dehydrogenase activity in the tumor, and exclusion of phage Ap-1. For 21 mutants affected in at least one of these functions, the map position of the deletions was determined. It was found that deletions at two separated loci give rise to an Occ^? phenotype. Genes for Ap-1 exclusion were mapped on a small region just outside and to the right of the T_L + T_R region. Most of the T_R region, present as T_R-DNA in a limited number of crown gall tissues only, was shown to be unnecessary for tumor formation, since it could be deleted without affecting virulence (tested on various plant species) of the mutants. However, if the T_R region together with a small part of the adjacent T_L region, which is always present as T_L-DNA in normal crown gall tissues, was deleted the mutants became weakly virulent on Kalanchoë and Nicotiana rustica and avirulent on tomato. We hypothesize that in this case a region necessary for T-DNA integration has been deleted. The same region was found to be essential for lysopine dehydrogenase activity in the tumors.