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.

     

Inverse Diauxy in the Yeast Hansenula anomala: Mutants Derepressed for Malic Acid Utilization in the Presence of Glucose

Utilization of l-malic acid by yeast strain Hansenula anomala IGC 4380 is subject to glucose repression. Derepressed mutants were obtained with UV light by use of the nonmetabolizable glucose analog 2-deoxyglucose as a selective agent. Three mutant strains degraded l-malic acid in the presence of up to 30% (wt/vol) glucose and are of potential interest for the biological deacidification of grape must. The mutant strains, as compared with the parent strain, displayed inverse diauxy in glucose-malate medium, glucose being metabolized only after malate consumption had been completed.     

A possible mechanism of high temperature dormancy regulation in seeds of Avena sativa L. (cv. Moyencourt)

Embryos of Avena sativa L. (cv. Moyencourt) show no high temperature dormancy. The dormancy is induced by the presence of endosperm-aleurone part of the seed. Germination of isolated embryos at 30°C can be prevented by ABA and the inhibition is reversed by GA. Inhibitors of GA synthesis also inhibit embryo germination. The embryos of dormant and non-dormant seeds vary greatly in their sensitivity to exogenous ABA. High temperature dormancy of the entire seeds can be relieved by low concentrations of ethanol. On the basis of these facts a hypothetic model is proposed showing how interaction between endogenous GA and ABA-like inhibitory substance, may regulate the high temperature dormancy of the seeds.     

Behavioral changes in pottos (Perodicticus potto): Effects of naturalizing an exhibit

Observations of the potto (Perodicticus potto),a nocturnal prosimian primate,indicated a limited behavioral repertoire and prompted renovation of their exhibit at the Frankin Park Zoo (Boston, MA). We used the natural history of this species to direct the exhibit modifications, which used only nonsynthetic items. We added live plants, soil, bamboo, shelf fungi, grapevines, a hollow tree, and a log containing an insect dispenser to the exhibit at little expense. They provided new textures, odors, pathways, stimulation and cover for this secretive species. The changes produced a heightened aesthetic appeal to the nocturnal exhibit and improved its educational value by representing the animals’ habitat more accurately. The exhibit modifications also resulted in a significant increase in activity, an expansion of the pottos’ behavioral repertoire,the emergence of sexual behaviors, and an increased visibility to the public.     

Somatic embryogenesis,organogenesis and callus growth kinetics of flax

The effects of plant growth regulators (PGR) on calli induction, morphogenesis and somatic embryogenesis of flax were studied. The organogenic and callus formation capacity were assessed for different types of source explants. Root and shoot explants were equally good material for calli production but the former produced calli without shoot regeneration capacity. Under the experimental conditions tested, 2,4-dichlorophenoxyacetic acid (2,4-D) + zeatin was the most efficient PGR combination on calli induction and biomass production. The calli were green but with no rhizogenic capacity. In contrast, and at similar concentrations, indole-3-butyric acid (IBA) + kinetin induced white or pale green friable calli with a good root regeneration capacity (60%). A factorial experiment with different combinations of 2,4-D + zeatin + gibberellic acid (GA₃) levels revealed that the direction of explant differentiation was determined by specific PGR interactions and concentrations. The results from these experiments revealed that the morphogenetic pathway (shoot versus root differentiation) can be manipulated on flax explants by raising the 2,4-D level from 0.05 to 3.2 mg l^?1 in the induction medium. The induction and development of somatic embryos from flax explants was possible in a range of 2,4-D + zeatin concentrations surrounding 0.4 mg l^?1 2,4-D and 1.6 mg l^?1 zeatin, the most efficient growth regulator combination.     

The management of European estuaries: A comparison of the features,controls and management framework of the Tagus (Portugal) and Humber (England)

The paper describes the local, national, European and wider-area framework, statutes, and formal and voluntary mechanisms for managing European estuaries. These aspects are discussed in relation to two large and representative estuarine systems, the Tagus, Portugal, and the Humber, on the English North Sea coast As estuaries are sites of many activities and uses, most of which are encouraged or at least condoned, management has the role of preventing and resolving conflicts between those uses and users. Accepted uses of estuaries include the discharge and dumping of waste materials, fin and shell-fisheries, conservation, land reclamation, natural usage, abstraction by industry, and recreation. Estuarine management is now being carried out within the constraints of local and regional government planning, planning and activities of water pollution control bodies, fisheries control bodies, and navigation and port authorities The Tagus and Humber estuaries support all of the above activities and uses, and have controls within a European legislative framework but have differing histories of management and planning in order to resolve conflicts. In addition the Humber is subject to controls placed on North Sea areas. The paper discusses the relevant national and European legislation (Directives) and accepted practices for management. Furthermore, the paper discusses the formulation and practice of estuarine management plans as used by various bodies (nature conservation, water quality and regional authority). It is of particular note that the lessons from these two estuaries are relevant to many other European estuaries.