Ultrastructure de Quelques Stades de la Microsporidie Octosporea muscaedomesticae Flu, Parasite de Ceratitis capitata (Wiedemann) (Diptère, Trypetidae)

La présence de diplocaryons à tous les stades de la sporulation d'Octosporea muscaedomesticae Flu, 1911 est mise en évidence ainsi qu'une membrane pansporoblastique autour des sporoblastes en développement et des spores. Le problème présenté par ces 2 faits est discuté. Une évolution étrange des ribosomes périnucléaires et démontrée. Une telle étude ultrastructurale est nécessaire et intéressante car O. muscaedomesticae est l'espèce-type du genre Octosporea.     

Feline Leukaemia Viral Antigens and Antisera to the Group Specific Antigens of the Murine Leukaemia Viruses

GEERING et al.¹ reported that feline leukaemia viruses shared one of the group specific antigens of the murine leukaemia viruses, gs-3, as detected by immunoprecipitation in agar gels with broadly reactive rat antisera to the group specific antigens of the murine leukaemia viruses (MuLV). Subsequently, they found that this shared group specific antigen was also present in the hamster and rat C-type viruses². Work by Schafer³ and our own immunodiffusion⁴ and complement fixation studies have confirmed the immunological reactivity between the feline leukaemia viral antigens and broad-reacting murine leukaemia group specific antisera. We have now applied this interspecies immunological reaction between the murine and feline C-type viruses to quantitative studies of the feline leukaemia viruses. Broad-reactive murine leukaemia-sarcoma group specific antisera prepared in rats by the induction of murine sarcoma virus (MSV) tumours^{5, 6} were found to be as useful and nearly as sensitive as a feline leukaemia-sarcoma specific, group specific antiserum for the in vitro detection and assay of the noncytopathogenic feline leukaemia virus (FeLV).     

Marine Ostracoda of the Galapagos Islands and Ecuador

Marine algae collected from rock pools on Hood, Fernandina and Mosquera, in the Galapagos Islands, have provided a fauna of 26 ostracod species of which 14 are new. One genus, belonging to the Hemicytheridae, is also new and appears to be endemic to the Islands. From two littoral algal samples collected from Punta Canoa and San Pedro beach, Ecuador, an assemblage of some nine species, four of which are new, is also described. Two ostracods: Touroconcha lapidiscola and Loxoconcha (Lox-ocorniculum) lenticuloides , are the only species so far known to be present both in the Galapagos Islands and off the coast of Central and South America. One species: Cytherelloidea praecipua recorded from off Tobago and Clipperton Islands may be present in the Galapagos but this has not definitely been confirmed. The evolution in the Gulf Coast/Caribbean region of several ostracods and their subsequent dispersal westwards is discussed.     

Isolation of the Antheridiogen of Anemia phyllitidis

The antheridiogen (antheridium-inducing substance) of the fern species Anemia phyllitidis has been obtained in pure form based on the isolation procedure described below. Pure antheridiogen is active to a dilution of 10 μg/l in antheridium formation and 0.3 μg/l in dark-germination. Its molecular formula is C₁₉H₂₂O₅.     

End Product Inhibition of Serotonin Synthesis in the Rat Striatum

THE synthesis of serotonin (5-HT) in central serotoninergic neurones seems to depend on the intraneuronal concentrations of the amine. After acute or chronic treatment with a monoamine oxidase inhibitor (MAOI), which induced more than a three-fold increase in 5-HT concentrations, we observed a reduced formation of ³H-5-HT from ³H-tryptophan in the rat brain¹. More precisely, this effect could be seen by measuring the accumulation of ³H-5-HT in tissues 15 min after the intracisternal injection of ³H-tryptophan at various times after pheniprazine or pargyline treatments. The ³H-amine accumulation was much less after 3 h than 0.5 h after the MAOI injections. The existence of a 5-HT synthesis regulation by end product inhibition occurring at the first limiting step was proposed to explain these results¹.     

C-Type Virus associated with Gibbon Lymphosarcoma

C-TYPE viruses have been established as the causal agents of leukaemia in murine and feline species and have been characterized^1,2. C-type virus is also probably associated with fibrosarcoma in non-human primates^3–6. To determine whether viruses with identical characteristics are associated with other neoplasms in simian species, we looked for C-type viruses in cases of leukaemia. A gibbon (Hylobates lar) with a disseminated tumour (later confirmed as lymphosarcoma) was made available to the Comparative Oncology Laboratory by Dr Malcolm Jones of the University of California, San Francisco Medical Center. The principal sites of involvement (lymph node, liver and bone marrow) were extensively overrun with massive neoplastic cells, which were predominantly prolymphocytic forms. Electron microscopy revealed C-type particles identical to those observed in vitro in sections from lymph nodes, liver, spleen and bone marrow.     

Distribution of planktonic ciliates in highly coloured subtropical lakes: comparison with clearwater ciliate communities and the contribution of myxotrophic taxa to total autotrophic biomass

SUMMARY 1. The planktonic ciliate communities of eleven organically coloured north and central Florida lakes representing a variety of trophic conditions were examined during 1979–80. The total abundance and biomass of ciliates were not significantly different from comparable clearwater lakes and only minor taxonomic replacements were noted at the order level.
2. Timing of population peaks of oligotrophic lakes was dissimilar to clearwater lakes of the same trophic state, but seasonality in meso-trophic and eutrophic lakes resembled patterns described for comparable clearwater lakes.
3. Various ciliate components were strongly correlated with chlorophyll a concentrations, but only moderately correlated to dominant phytoplankton groups. No significant correlations were found between ciliate components and bacterial abundance.
4. Myxotrophic taxa numerically dominated oligotrophic systems, particularly during midsummer, and accounted for a large percentage of the total ciliate biomass. Estimates of the ciliate contribution to total autotrophic biomass indicate that these zoochlorellae-bearing protozoa may account for much of the autotrophic biomass during midsummer periods in coloured lakes, and thus may lead to an overestimation of phytoplankton standing crops available to zooplankton grazers if chlorophyll a is used as a surrogate measure of algal biomass.     

Comparative day and night feeding strategies of shorebird species in a tropical environment

A study was carried out in northeastern Venezuela to determine whether or not shorebirds feed at night in tropical environments. Results show that some Neotropical residents and Nearctic winter migrants feed during darkness. During daylight, Black-winged Stilts Himantopus himantopus, mexicanus group, were predominantly visual foragers (75% attempts were pecking), performing a tactile type of feeding technique (immersion of the whole head and portion of the neck while searching for food through soft mud) on other occasions. During night-time, they were almost equally visual (pecking) and tactile (multiple scythelike sweeps) foragers. Greater and Lesser Yellowlegs Tringa melanoleuca and T. flavipes foraged visually during daylight and tactilely (sidesweeping) at night. Short-billed Dowitchers Limnodromus griseus were tactile feeders (probers) both by day and by night while Semipalmated Plovers Charadrius semipalmatus during daylight and at night and Wilson's Plovers C. tvilsonia by night were sight feeders (peckers). Prey abundance was higher at night than during daylight. Black-winged Stilts and yellowlegs seemed to feed at night on food items at least partly different from those they fed upon during daylight.     

Maternal attendance and the maintenance of family groups in common earwigs (Forficula auricularia): a field experiment

Abstract.  1. Understanding the evolution of subsocial behaviour and parental care requires experimental tests of the functional significance of such behaviours and the role of tending parents in the maintenance of family groups. Studies in subsocial insects addressing these issues experimentally and in the field are still relatively rare.
2. In such a field experiment, it is demonstrated here that the presence of tending females enhances the maintenance of family groups in common earwigs, Forficula auricularia (Dermaptera; Forficulidae). Experimental removal of tending mothers resulted in substantially decreased recovery of occupied nest burrows and larvae. This effect may have been because of decreased survival among experimental larvae, although a possible role for enhanced larval dispersal could not be fully ruled out.
3. Experimental (motherless) larvae were partly observed in family groups with a tending female, in both experimental and control nest burrows, suggesting that these larvae had been adopted by family groups moving to new nest burrows, and/or that experimental larvae may have actively joined other family groups.
4. This study demonstrates under field conditions the functional importance of maternal attendance for the maintenance of family groups in common earwigs, and suggests that adoption and clutch-joining are factors affecting the social structure of this species.     

Moral Sentiments and Material Interests: The Foundations of Cooperation in Economic Life

Moral Sentiments and Material Interests: The Foundations of Cooperation in Economic Life . Herbert Gintis, Samuel Bowles, Robert Boyd, and Ernst Fehr, eds. Cambridge: MIT Press, 2005. 404 pp.