Effects of storage on germination ofDioscorea composita (Dioscoreaceae) seeds

Effects of storage were tested on germination ofDioscorea composita (Dioscoreaceae) seeds. Freshly collected seeds and seeds stored at 25°C in paper bags from 1 to 11 mo or for 4 and 5 yr were used in most of the experiments. Seeds were tested for germination at 20, 25, 30, 35, 25–20, and 25–35°C in white light and in darkness. Initiation of germination was delayed in freshly harvested seeds, and dormancy was reduced in seeds stored for about 9 mo. Viability of the seeds decreased after 4 and 5 yr of storage.     

Juvenile hormone esterases of Lepidoptera

Summary The juvenile hormone esterase (JHE) titer was measured during the last larval instar of 11 species of Lepidoptera (Pieris rapae, Junonia coenia, Danaus plexippus, Hemileuca nevadensis, Pectinophora gossypiella, Spodoptera exigua, Orgyia vetusta, Ephestia elutella, Galleria mellonella, Manduca sexta andEstigmene acrea). All species had a peak of JHE at or near the time of wandering. The peak activity at this time ranged from 0.8 to 388 nmoles JH III cleaved/min·ml. All species exceptJ. coenia had a second peak of JHE during the late prepupal stage. The height of the second peak ranged from 0.4 to 98.4 nmoles/min·ml. However, there was no apparent correlation between size of the first and second JHE activity peaks for the lepidopteran species examined. There was an apparent relationship between the height of the first and second JHE peaks and reports on titer of JH just prior to these peaks. These data support, with some qualifications, the extension of developmental information obtained on several well studied species to a variety of Lepidoptera.Abbreviations JH juvenile hormone - JHE juvenile hormone esierase - PTTH prothoracotropic hormone - R _o -10-3108 1-(4-ethylphenoxy)-6,7-epoxy-3-ethyl-7-methylnonane     

Culture of Candida in vinasse and molasses: Effect of acid and salt addition on biomass and raw protein production

Species of the genera Candida grown in vinasse and molasses were studied under the following conditions: agitation of containers, pH 4.6, culture time of 24 hours at 30°C. The greatest biomass production of C. krusei grown in vinasse was obtained with the addition of 0.1% H₃PO₄, and of C. guilliermondii and C. utilis with the addition 0.02% urea plus 0.03% H₃PO₄. Protein levels near 50% were found in C. utilis in vinasse supplemented either with molasses, with 0.05% MgSO₄, or with 0.02% urea plus 0.03% H₃PO₄.     

Actin organization and fibrin-clot retractile activity of cultured mouse fibroblasts

Summary It is known that human and animal fibroblasts are able to induce the retraction of a fibrin clot. In the present study the correlation between (i) fibrinclot retractile (FCR) activity, (ii) the number of actin stress-lines in mouse fibroblasts during growth in culture, and (iii) the sensitivity of actin stress-lines to a powerful actin-depolymerizing factor (ADF), present in plasma and serum of humans and laboratory animals was investigated. Fibroblasts at early passages (2–4) were tested for these parameters at various intervals after seeding (24, 96, and 168 h). The number of actin stress-lines was progressively higher, while the sensitivity to ADF action was progressively lower in cells cultured from 24 to 168 h; the FCR capacity was significantly decreased at 168 h. These data suggest that cells containing weakly polymerized and/or stabilized actin are more active than those containing highly polymerized and/or stabilized actin in triggering fibroblast contraction.     

Age-dependent population diffusion with external constraint

We present a simple model for age dependent population diffusion when the dynamics is submitted to external constraints. Existence, uniqueness and dependence on the parameters of the solution are discussed.This work has been done within the framework of the cultural agreement between the Universities of Bordeaux and Rome     

Lysis of autologous human melanoma cells by in vitro allosensitized peripheral blood lymphocytes

Summary Peripheral blood lymphocytes (PBL) of melanoma patients were sensitized in vitro with lymphocytes of a single donor or with a pool of lymphocytes of 5–20 different donors. After 6–7 days, the cytotoxic activity of the sensitized PBL was tested against cultured autologous tumor cells and lymphocytes in a ⁵¹Cr-release assay. Tumor lysis was observed in 13 of 16 cases in which patients' PBL (Pt-PBL) were stimulated by a pool of allogeneic lymphocytes and in five out of seven cases when single sensitization was performed. In no case was lysis of autologous normal lymphocytes or blasts seen. Cultivation of Pt-PBL with irradiated autologous tumor cells never led to the induction of lymphocytes cytotoxic to melanoma cells. Lysability by pool-activated autologous Pt-PBL of fresh cryopreserved tumor cells was compared to that of short-term cultured tumor cells, and no significant differences were observed. Cold-target inhibition experiments indicated that the cytotoxicity of Pt-PBL was tumor-restricted since only autologous melanoma cells but not lymphocytes were able to inhibit the reaction. These results indicate that activation of Pt-PBL is necessary in order to elicit or amplify their antitumor activity.     

The Roberts syndrome

Summary Four siblings with the autosomal recessive Roberts syndrome are reported, and we discuss the phenotypic overlap of this syndrome with other similar radial, aplasia syndromes.     

Permeabilization of yeast for in situ determination of α-glucosidase

A quantitative in situ assay of yeast α-glucosidase involving permeabilization of the cells by freezing and thawing is described. The assay was applied to different strains in different physiological states and was shown to give results comparable to those obtained with total cell homogenates. The primary advantage of the in situ assay was the possibility of analyzing a large number of samples from the same culture during a growth curve using a very reduced cell mass.     

Pathogenesis of infection by the hyphomycetous fungus,Tolypocladium cylindrosporum inAedes sierrensis andCulex tarsalis [Dip.: Culicidae]

The mode of infection and cycle of development ofTolypocladium cylindrosporum Gams was examined inAedes sierrensis andCulex tarsalis. Larvae were found to be infected through the external cuticle, the pharynx and the midgut. Blastospores and conidia were both infective although for equal numerical concentrations blastospores proved more virulent causing high mortality within the first 48 h after inoculation (80 % for L2 larvae exposed to 5×10⁵ spores/ml), while conidia generally took 7–10 days to produce the same results. Sporulation did not occur on submerged cadavers. Conidia were produced only on floating cadavers in contact with air. Conidial production on floating 4th instar larvae was found to average 1.8×10⁷ conidia/larva. Invasion of the haemocoele and fairly extensive growth of the fungus almost invariably occurred before larvae were killed. This was particularly true forAedes sierrensis larvae. Details are presented of growth within the host and post-mortem penetration of the fungus out of the cadaver. AdultA. sierrensis sprayed with a conidial suspension proved susceptible to infection with 100 % mortality being recorded at 10 days. Infections originated in the thorax, suggesting, the integument or possibly the thoracic spiracles to be the most probable site of infection.