Allometric relations of total volumes of prolactin cells and corticotropic cells to body length in the annual cyprinodont Cynolebias whitei: effects of environmental salinity,stress and ageing

Summary An analysis of the allometric relations of the total volumes occupied by prolactin (PRL) and corticotropic (ACTH) cells (PRL volume and ACTH volume, respectively) to body length and a study of the immunocytochemical staining intensity of PRL and ACTH cells were used to determine the differences in activity of PRL and ACTH cells in freshwater-reared and in saltwater-reared Cynolebias whitei during the entire lifespan of this annual cyprinodont fish. An inflection in the allometric relation of PRL volume to body length was observed in fish of one-week old. The relatively large PRL volume in younger fish may be related to PRL cell activity before hatching. No inflections were observed in the allometric relations of PRL volume and ACTH volume to body length at the onset of maturation and the onset of ageing, indicating that the increased pituitary growth in maturing and ageing C. whitei is not the result of changes in PRL or ACTH cells. The slope of the allometric relation of PRL volume to body length in freshwater-reared fish was significantly steeper than the slope in saltwater-reared fish. The PRL volume in adult freshwater-reared fish was eight times larger than that in saltwater-reared fish of the same length. The intensity of immunocytochemical staining of saltwater PRL cells was significantly reduced. These volumetric and staining differences correspond to the low functional demand put upon PRL cells in saltwater-adapted fish. In contrast, the slope of the allometric relation of ACTH volume to body length and the intensity of immunocytochemical staining of ACTH cells were similar in freshwater-reared and in saltwater-reared fish. It is concluded that the functional demand put upon ACTH cells is similar in freshwater-reared and saltwater-reared C. whitei; the involvement of ACTH cells in the osmoregulation of the fish in both environments is similar.     

Agonistic behaviours in colonies of the bumblebeeBombus terrestris

The first aim of this study was to investigate whether specific changes in the frequencies of behavioural characteristics are correlated with the cause or reflect the onset of the laying of haploid eggs by the queen, and whether these changes cause the onset of egg laying and aggressive behaviour by workers. The second aim was to obtain a better understanding of the occurrence of the behaviours in relation to the physiology and function of the queen and the workers. No behavioural characteristics of workers which could predict the occurrence of the queen's switch to haploid egg laying was found nor did any such behaviour indicate that the switch had already occurred. The onset of worker oviposition was not found to be the consequence of the level or the type of agonistic actions between the workers and the queen. With the onset of worker oviposition the agonistic behaviours called trembling and buzzing, which are directed at the queen, disappear. At the same time the frequency of a non-directed behaviour, called humming, increases. This behaviour is seen particularly in the small housebees with developed ovaries. Before worker oviposition begins, the frequencies with which individual workers perform agonistic behaviour are not correlated with the conditions of their ovaries nor correlated with other characteristics of the workers. However, these frequencies are related to the sequence in which workers emerge. The correlations with age are due to the fact that workers of the first brood have higher activity levels than those of the later broods. The first egg layers are to be found among the first workers. In the period of worker oviposition, humming and the aggressive behaviours of darting and attack are performed by workers with developed ovaries. These behaviours are directed particularly towards workers who also have active ovaries. If the queen has disappeared 1 worker usually becomes dominant. This worker is characterized by the relatively high frequency with which she engages in darting and attacks. In addition, this worker is characterized by a specific behaviour, called pumping, which is directed at workers that have mature eggs in their ovaries. Behavioural domination, however, is no guarantee that the bee concerned will eventually become the most productive one. Although at an apparently pre-determined moment in the ontogeny of the colony the queen loses control over worker oviposition and related behaviours, she remains dominant in various other behavioural hierarchies. It is therefore concluded that the queen never loses dominance completely.     

Age,seasonal and diel variations of the uricolytic enzymatic system in the snailsXeropicta arenosa (Ziegler) andCernuella virgata (Da Costa)

Summary The nitrogen catabolism of two snail species,Xeropicta arenosa andCermuella virgata, living on coastal dunes, was studied at different seasons and times of the day and at different ages. All the nitrogenous metabolites of the uricolytic enzymatic system were found in body homogenates of the snails, although uric acid was most abundant. The highest levels of these catabolites were observed during the day when the snails were inactive, while the lowest levels occurred during the night when excretion probably took place. The levels of most of the nitrogenous catabolites and the activities of the enzymes were higher in juveniles than in adults.All the enzymes of the uricolytic pathway were shown to be present in bothX. arenosa andC. virgata.     

A new species of pagamea (Rubiaceae) from the Brazilian Guayana

Pagamea aracaënsis Boom, endemic to Serra Aracá, Brazil is described and illustrated, and its relationship toP. anisophylla Standley & Steyerm, is discussed.     

Rapid detection and identification of Legionella pneumophila by a membrane immunoassay.

Legionella pneumophila was detected and identified by an immunoblot assay using a monoclonal antibody specific to serogroups 1 to 8. Samples containing L. pneumophila were plated on buffered charcoal yeast extract agar supplemented with glycine, vancomycin, and polymyxin B. After incubation at 35 degrees C for 3 days, colonies were transferred to nitrocellulose membranes by blotting. Simultaneous detection and identification of L. pneumophila were done by treating the membrane with the monoclonal antibody and a peroxidase conjugate to mouse immunoglobulins. A diffuse cross-reaction was observed with Pseudomonas fluorescens colonies, but this was a low-level reaction that could easily be differentiated from the strong specific reactions to L. pneumophila.     

Lucigenin chemiluminescence and its relationship to mitochondrial respiration in phagocytic cells

Unstimulated alveolar macrophages, but not polymorphonuclear leukocytes, elicit chemiluminescence from lucigenin which cannot be entirely accounted for by the resting level of superoxide generation. This chemiluminescence was inhibited by both superoxide scavengers and inhibitors of mitochondrial respiration. Although 12-O-tetradecanoyl phorbol-13-acetate addition resulted in a significant increase in cellular superoxide generation, an unexpected decrease in lucigenin chemiluminescence was noted. These results suggest that mitochondria in alveolar macrophages may be a site of lucigenin accumulation and dioxygenation and that 12-O-tetradecanoyl phorbol-13-acetate may modulate this activity.     

Transformation of mouse BALB 3T3 cells by enterobacterial plasmid misrepair gene mucAB.

The enterobacterial plasmid misrepair gene mucAB, ligated to the metal-inducible mammalian MT-1 promoter, was introduced into the genome of mouse BALB 3T3 cells. In the presence of zinc ions, MucA but not MucB protein was produced, and the whole-cell population of each mucAB+ clone started to show the transformation phenotype in a few days. Foci appeared in the transformed cell population after 4 weeks, and cells from the foci produced tumors in nude mice, indicating malignant transformation by the mucA product. Growth of mucAB+ cells was stimulated by zinc-induced expression of mucA. The transformation phenotype was reversed by removing zinc ions from the culture, indicating that the transformation was due not to MucA-mediated mutation in the mouse genome but to the direct transforming activity of MucA protein.