Cultural characteristics and zearalenone production by strains of<Emphasis Type="Underline">Fusarium</Emphasis> from wheat

Conidia of the speciesFusarium culmorum /W.G.Sm./ Sacc. andFusarium graminearum Schwabe are characterized by variability in zearalenone production and dimensions depending on the substrate. The sporulation of isolates from some wheat eultivars have been deprived in vivo and in vitro in the first passage, but not their pathogenicity and toxic metabolites production. Nonsporulating strains produced lower quantités of zearalenone than sporulating ones. Liquid filtrates of such nonsporulating strains had a high phytotoxic effect on wheat caryopses. The crystalline toxin DAS /0,25 ug/ml/ had low phytotoxic effect on wheat caryopses.     

Effect of endurance training and chronic isoproterenol treatment on skeletal muscle sensitivity to norepinephrine

The purpose of this study was to determine the influence of metabolic stresses, such as endurance training and chronic isoproterenol treatment, on skeletal muscle sensitivity to norepinephrine. Using an isolated perfused rat hindlimb preparation, dose-response curves for skeletal muscle oxygen consumption (VO2) and vascular resistance were obtained with control, endurance trained, and isoproterenol treated rats. No significant difference was found between control and experimental groups for non-stimulated VO2. In response to NE infusion, trained rats showed a significantly greater increase in VO2 compared to control rats while the response of the isoproterenol treated rats was of the same magnitude as the one for their respective control rats. At the highest dose of NE infused, the vasopressor response was significantly lower in trained rats compared to control rats. At none of the doses was there a significant difference in the vasopressor response between control and isoproterenol treated rats. These results suggest that repeated exposures to high levels of catecholamines, as produced during endurance training, leads to an increased sensitivity of skeletal muscle to the effect of norepinephrine.     

Performance ofin vitro propagatedAlnus glutinosa (L.) Gaertn. clones inoculated withFrankiae

Summary ThreeAlnus glutinosa (L.) Gaertn. clones, obtained byin vitro propagation techniques, were inoculated with four strains ofFrankia. The ability of these clones to nodulate and fix nitrogen was previously reported; this study deals with the performance of 12 different combinations of pairs of symbionts.Shoot fresh weight, shoot height and collar diameter were measured 60 and 82 days after inoculation. Shoot fresh weight seems to be more sensitive and reliable than the other parameters. Nitrogenase activity, measured by the acetylene reduction assay, was assayed 78 days after inoculation and was consistent with the biomass measurements.Better growth was observed when type N strains were used. Significant growth differences were observed between clones AG-2 and AG-8 on the one hand and clone AG-4 on the other. Thus, the use of genetically defined host plants and microsymbionts permitted the demonstration of significant performance variation even among cloned plants from the same provenance (AG-4 and AG-8).The duration of the experiment influenced the results with differences becoming less significant with time. This might be caused by an external limiting factor such as the pot size, competition for light,etc. But it could also be indicative of differences in nodulation speed among the treatments.     

Statistical mechanics of DNA and protein suitable for computer calculation

The metling behavior of DNA and formation of α-helices and β-strands in protein can be discussed rigorously by statistical mechanical treatment. To do this, however, appropriate formulations are required for fast computer calculation. New formalisms for DNA and protein in terms of recurrence relations suitable for computer calculation are presented.     

Seasonal changes in ovarian state in a eusocial halictine bee,Lasioglossum duplex,based on stages of the oldest oocytes in each ovariole (Hymenoptera: Halictidae)

Summary The changes in ovarian activity in the life cycle of the eusocial halictine beeLasioglossum (Evylaeus) duplex (Dalla Torre) was studied in both queens and workers by examining the stages of the terminal follicle in each of the six ovarioles. By this method, ovarian activities of both queens and workers were more quantitatively determined than by observation of gross ovarian features as usually conducted. Queen ovaries clearly exhibited two active periods, corresponding to the spring solitary phase and the summer eusocial phase, with distinctly greater activity in the latter. In ovaries of overwintering queens oosorption of young follicle was observed. Worker ovaries were found more active in orphan than in queenright colonies. The order of ovarian activity obtained from pooled data, summer queens>spring queens>orphan workers>queenright workers, was also recognized by comparison of individual females. Bionomics of the eusocial halictine beeLasioglossum duplex IX. Contribution No. 3107 from the Inst. Low Temp. Sci.     

On the dynamics of the mass mortality of Diadema antillarum in Barbados

Widespread mortality of the black sea urchin Diadema antillarum occurred in the Caribbean in 1983; beginning in Panama in January, and having its major impact at Barbados in September. Mortality on ten reefs surveyed in Barbados was 93.2%, with the highest being 99.9% and the lowest 86.9%. Mortality on each reef was independent of the pre-mortality density on the reef. Urchins with test diameters between 20 and 40 mm were more severely affected than smaller or larger urchins. Populations on reefs exposed to incoming oceanic water suffered heavier mortality than those on protected reefs. Mean size of urchins was smallest on high density reefs. This may indicate a negative effect of density on urchin growth. At post-mortality densities, urchins may grow faster and reach sexual maturity sooner.     

Distribution of corticotropin-releasing factor in ovine brain determined by radioimmunoassay

We have developed and used a sensitive and specific radioimmunoassay to demonstrate the presence of CRF-like immunoreactivity in extra-hypothalamic areas of ovine brain. Synthetic CRF displaced antibody bound tracer at an ED50 value of 200 pg and there was no cross-reactivity with LHRH, TRH, ACTH, beta-endorphin and several other peptides. Displacement of bound 125I-CRF by brain extracts exhibited curves parallel to synthetic CRF standards. Highest concentrations (1 ng/mg tissue) of CRF-like immunoreactivity were found in the median eminence but surprisingly, high concentrations of CRF-like immunoreactivity were found in frontal, parietal, occipital and particularly temporal areas of cerebral cortex. Much lower concentrations were found in other brain areas including the basal ganglia, limbic system and brain stem.     

Die malakologische gliederung einiger buchenwaldtypen in nordwest-Deutschland

Zusammenfassung Die Pflanzengesellschaften werden als objektive Einheiten der Erdoberfläche angesehen, die als Grundlage für biosoziologische Untersuchungen dienen können. Die verschiedenen bislang angewandten Untersuchungsverfahren zur quantitativen Erfassung des Tierartenbestandes eines einheitlichen Gebietes wereden angeführt und erörtert. Die eigenen Untersuchungen wurden in Probeflächen des Melico- und Carici-Fagetum durchgeführt. Dabei wurden mehrere Probequadrate von 25×25 cm abgesteckt und zu einer Probefläche zusammengefaßt. Zur Angabe der Frequenz und Abundanz wird ein Klassensystem benutzt (+, 1 bis 5). In Waldgesellschaften sind mindestens 8 Probequadrate erforderlich. Der Vergleich mehrerer einheitlicher Bestände ergibt die Konstanz (I bis V). Für das Carici-Fagetum lassen sich Abida secale, Clausilia parvula und Iphigena plicatula als Kenn-Arten ausscheiden. Die Artenzahl ist im Melico-Fagetum geringer. Einige Arten können evtl. als geographische Differentialarten angesehen werden.

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Summary The plant associations are considered to be objective units of the earth surface which may be a basis for biosociological researches. The different methods used for quantitative studies of the animal species of a homogeneous area are recorded and discussed. Own studies of the Melico-Fagetum and Carici-Fagetum have been carried out in northwestern Germany. Several sample squares of 25×25 cm are marked out and treated as a whole called sample area. Frequency and abundancy are represented by five classes (1 to 5). In wood communities 8 sample squares are necessary. The constancy means the frequency within several homogeneous sites (I to V). Thus it was found that the Carici-Fagetum is characterized by Abida secale, Clausilia parvula and Iphigena plicatula as euconstant species. The number of species is less in the Melico-Fagetum. Some species may be defined as geographically differentiating species.

     

Dual action of anti-sporozoite antibodies in vitro

With the use of a double staining technique that permits localization of the sporozoite during the process of entering a host cell, we studied the biologic effects of three mAb directed against determinants contained in the circumsporozoite of Plasmodium yoelii. These mAb, which included one IgM and two IgG3, were studied in primary cultures of rodent hepatocytes inoculated with sporozoites of P. yoelii. These results confirm previous reports of the extended action of antibodies on Plasmodium falciparum after entering hepatocytes by producing a strong intrahepatocyte inhibitory effect in addition to the inhibitory effect on sporozoite entry. As with P. falciparum the intracellular effects on P. yoelii liver stages are only observed when the antibodies are present at the time the sporozoite enters the cell. While carrying out experiments on this phenomenon, it was discovered that, at lowered antibody concentrations, an increase in number of maturing liver schizonts occurs, with the increase or enhancement of infection reaching up to 150% of that of controls. It was also observed that there was an inverse relationship between the antibody concentration that was inhibitory and that which enhanced parasite infectivity.