Dopaminergic neurons in the brain and dopaminergic innervation of the albumen gland in mated and virgin helisoma duryi (mollusca: pulmonata).
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BACKGROUND: Dopamine was shown to stimulate the perivitelline fluid secretion by the albumen gland. Even though the albumen gland has been shown to contain catecholaminergic fibers and its innervation has been studied, the type of catecholamines, distribution of fibers and the precise source of this neural innervation has not yet been deduced. This study was designed to address these issues and examine the correlation between dopamine concentration and the sexual status of snails. RESULTS: Dopaminergic neurons were found in all ganglia except the pleural and right parietal, and their axons in all ganglia and major nerves of the brain. In the albumen gland dopaminergic axons formed a nerve tract in the central region, and a uniform net in other areas. Neuronal cell bodies were present in the vicinity of the axons. Dopamine was a major catecholamine in the brain and the albumen gland. No significant difference in dopamine quantity was found when the brain and the albumen gland of randomly mating, virgin and first time mated snails were compared. CONCLUSIONS: Our results represent the first detailed studies regarding the catecholamine innervation and quantitation of neurotransmitters in the albumen gland. In this study we localized catecholaminergic neurons and axons in the albumen gland and the brain, identified these neurons and axons as dopaminergic, reported monoamines present in the albumen gland and the brain, and compared the dopamine content in the brain and the albumen gland of randomly mating, virgin and first time mated snails. (+info)
Emended description of Buttiauxella agrestis with recognition of six new species of Buttiauxella and two new species of Kluyvera: Buttiauxella ferragutiae sp. nov., Buttiauxella gaviniae sp. nov., Buttiauxella brennerae sp. nov., Buttiauxella izardii sp. nov., Buttiauxella noackiae sp. nov., Buttiauxella warmboldiae sp. nov., Kluyvera cochleae sp. nov., and Kluyvera georgiana sp. nov.
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A total of 219 strains belonging to the genera Buttiauxella and Kluyvera were studied; 171 of these strains were isolated from mollusks, mainly snails and slugs, obtained from around the world. On the basis of DNA-DNA hybridization data, the strains were grouped into 11 genomospecies. A total of 44 phenotypic characters were used to differentiate the genera Buttiauxella and Kluyvera at the genus level and to identify genomospecies. There were significantly higher phenotypic probability distances between the genomospecies in the genus Battiauxella and the genomospecies in the genus Kluyvera than between the genomospecies in the same genus. Therefore, the existence of Buttiauxella and Kluyvera as different genera was confirmed. The existence of new species necessitated broadening the definitions of both genera. In two cases, Buttiauxella species could not be quantitatively differentiated biochemically, and several other pairs of species could be separated only by the results of one biochemical test. Nonetheless, combinations of several characteristics were used in differentiate all of the species with levels of certainly ranging from log 10.79 to log 57.77 (calculated as probability distances). The following new species are proposed: Buttiauxella ferragutiae (type strain, ATCC 51602 [DSM 9390]), Buttiauxella gaviniae (type strain, ATCC 51604 [DSM 9393]), Buttiauxella brennerae (type strain, ATCC 51605 [DSM 9396]), Buttiauxella izardii (type strain, ATCC 51606 [DSM 9397]), Buttiauxella noackiae (type strain, ATCC 51607 [DSM 9401]), Buttiauxella warmboldiae (type strain, ATCC 51608 [DSM 9404]), Kluyvera cochleae (type strain, ATCC 51609 [DSM 9406]), and Kluyvera georgiana (type strain, ATCC 51603 [DSM 9409]). (+info)
Behavior and reproduction of invertebrate animals during and after a long-term microgravity: space experiments using an Autonomous Biological System (ABS).
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Aquatic invertebrate animals such as Amphipods, Gastropods (pond snails), Ostracods and Daphnia (water flea) were placed in water-filled cylindrical vessels together with water plant (hornwort). The vessels were sealed completely and illuminated with a fluorescent lamp to activate the photosynthesis of the plant for providing oxygen within the vessels. Such ecosystem vessels, specially termed as Autonomous Biological System or ABS units, were exposed to microgravity conditions, and the behavior of the animals and their reproduction capacity were studied. Three space experiments were carried out. The first experiment used a Space shuttle only and it was a 10-day flight. The other two space experiments were carried out in the Space station Mir (Shuttle/Mir mission), and the flight units had been kept in microgravity for 4 months. Daphnia produced their offspring during a 10-day Shuttle flight. In the first Mir experiment, no Daphnia were detected when recovered to the ground. However, they were alive in the second Mir experiment. Daphnia were the most fragile species among the invertebrate animals employed in the present experiments. All the animals, i.e., Amphipods, pond snails, Ostracods and Daphnia had survived for 4 months in space, i.e., they had produced their offspring or repeated their life-cycles under microgravity. For the two Mir experiments, in both the flight and ground control ecosystem units, an inverse relationship was noted between the number of Amphipods and pond snails in each unit. Amphipods at 10 hours after the recovery to the ground frequently exhibited a movement of dropping straight-downward to the bottom of the units. Several Amphipods had their legs bent abnormally, which probably resulted from some physiological alterations during their embryonic development under microgravity. From the analysis of the video tape recorded in space, for Ostracods and Daphnia, a half of their population were looping under microgravity. Such looping animals could be observed still at the end of the 4 month stay in space. No looping behavior was noted for Amphipods and pond snails. (+info)
Concluding remarks of Autonomous Biological Systems (ABS) experiments.
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Team efforts for analysis on the Autonomous Biological Systems (ABS) space experiments are summarized here to conclude scientific findings, and to scope the extended studies in future. From the three experiments on Space Shuttle and Space Station Mir, a closed ecological system modeled by the ABS was verified to be capable of sustaining its members of animals and plants under space environment for a period of several months. The animals successfully completed their life cycle in space during the course of these experiments, this was the first time that the life cycle of higher organisms had been completed in space and ecological system. Importance of gravity for ecology was proven at the same time. Gravity is a dominant factor for ecology by formulating spatial patterns and distribution of members of ecological system. Under microgravity, the fate of ecological system was found highly sensitive against the variation of environmental factor, such as light illumination cycle. (+info)
Biogeographical concordance and efficiency of taxon indicators for establishing conservation priority in a tropical rainforest biota.
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Prioritizing areas for conservation requires the use of surrogates for assessing overall patterns of biodiversity. Effective surrogates will reflect general biogeographical patterns and the evolutionary processes that have given rise to these and their efficiency is likely to be influenced by several factors, including the spatial scale of species turnover and the overall congruence of the biogeographical history. We examine patterns of surrogacy for insects, snails, one family of plants and vertebrates from rainforests of northeast Queensland, an area characterized by high endemicity and an underlying history of climate-induced vicariance. Nearly all taxa provided some level of prediction of the conservation values for others. However, despite an overall correlation of the patterns of species richness and complementarity, the efficiency of surrogacy was highly asymmetric; snails and insects were strong predictors of conservation priorities for vertebrates, but not vice versa. These results confirm predictions that taxon surrogates can be effective in highly diverse tropical systems where there is a strong history of vicariant biogeography, but also indicate that correlated patterns for species richness and/or complementarity do not guarantee that one taxon will be efficient as a surrogate for another. In our case, the highly diverse and narrowly distributed invertebrates were more efficient as predictors than the less diverse and more broadly distributed vertebrates. (+info)
Equine monocytic Ehrlichiosis (Potomac horse fever) in horses in Uruguay and southern Brazil.
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A disease named locally as churrio or churrido equino (i.e., equine scours) has occurred for at least 100 years in Uruguay and southern Brazil in farms along both shores of the Merin lake. This report describes cases of churrido equino and provides serologic, pathologic, and DNA-based evidence indicating that the disease is in fact equine monocytic ehrlichiosis (Potomac horse fever). Results of an epidemiological investigation conducted on an endemic farm are also presented. Clinical signs in 12 horses were fever, depression, diarrhea, dehydration, and sometimes colic and distal hind limb edema. Postmortem findings of 3 horses were of acute enterocolitis. Inclusion bodies containing ehrlichial organisms were found in the cytoplasm of macrophages of the large colon of 1 horse. Eleven of the 12 horses were serologically positive to Ehrlichia risticii (indirect fluorescent antibody assay) and, of 3 paired samples, 2 showed seroconversion. Ehrlichia risticii DNA was identified by a nested polymerase chain reaction in peripheral blood of an affected horse. A healthy horse inoculated with peripheral blood from an affected horse developed the disease and antibodies to E. risticii. The disease had a peak incidence in March (summer) and was statistically associated with a marshy ecosystem near the Merin lake, where large numbers of Pomacea spp. (Ampullariidae) snails were found. Incidence density was almost 8 times higher in nonnative horses than in native horses. It was concluded that the previous diarrheic disease of horses known in Uruguay and southern Brazil as churrido equino is equine monocytic ehrlichiosis. (+info)
Schistosomiasis epidemiology and control: how did we get here and where should we go?
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Although a disease of great antiquity, scientific studies of schistosomiasis began only 150 years ago. The complete life-cycle was not described until just before the First World War, making it possible at last to plan proper community control programmes. Inadequate tools prevented their effective implementation until well after the Second World War when new tools became available, thanks to the newly formed World Health Organization. Molluscicides spearheaded control programmes until the late 1970s but were then replaced by the newly developed, safe drugs still used today. Whatever the method used, the initial goal of eradication was, in the light of experience and cost, gradually replaced by less ambitious targets; first to stop transmission and then to reduce morbidity. The most successful programmes combined several methods to minimise reinfection after chemotherapy. Comparisons between different programmes are difficult without using appropriate, standardised diagnostic techniques and the correct epidemiological measurements. Some examples will be presented, mainly from our studies on Schistosoma mansoni in Kenya. Drug resistance on a scale comparable with malaria has not occurred in schistosomiasis but the likely withdrawal of all drugs except praziquantel leaves its control extremely vulnerable to this potential problem. An effective, affordable vaccine for use in endemic countries is unlikely to be ready for at least 5 years, and developing strategies for its use could take a further decade or more, judging from experience with drugs and molluscicides. In the interim, by analogy with malaria, the most cost-effective approach would the use of drugs combined with other methods to stop transmission, including molluscicides. The cost of molluscicides needs to be reduced and fears allayed about their supposedly adverse ecological effects. (+info)
Invading freshwater snails and biological control in Martinique Island, French West Indies.
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Eight alien freshwater snail species were introduced into Martinique Island during the last 50 years. The introduced snails include four planorbids (Biomphalaria straminea, Helisoma duryi, Amerianna carinata and Gyraulus sp.), three thiarids (Melanoides tuberculata, M. amabilis and Tarebia granifera) and one ampullarid (Marisa cornuarietis). Four of these species rapidly colonized the whole Martinican hydrographic system whereas the other four remained restricted to some particular sites. The invasion processes were documented during the last 20 years and showed (i) a rapid invasion of the island by several morphs of M. tuberculata at the beginning of the 80's; (ii) the introduction of T. granifera in 1991 and M. amabilis in 1997; and (iii) the rapid spread of these last two species throughout the island. In the years following its introduction, M. tuberculata was used in biological control experiments against the snail hosts of schistosomiasis, B. glabrata and B. straminea. Experiments were conducted with success in several groups of water-cress beds which constituted the latest transmission sites for schistosomiasis at the beginning of the 80's. A malacological survey carried out in 2000 all over the island showed the absence of B. glabrata but the presence of some residual populations of B. straminea. Long-term studies carried out in Martinique have shown that the thiarids are able to maintain relatively stable populations over a long period of time, thus preventing recolonization by the snail hosts. Within this context the invasion of the hydrographic system of Martinique by thiarid snails has resulted in an efficient and sustainable control of the intermediate hosts of schistosomiasis. (+info)