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The variation of resistance to (60)Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20, 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell (60)Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL(50/30) = 218.2 Gy) was found greater than in cross-fecundation forms. These data point to a low radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon.  相似文献   

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Injecting ecdysterone makes pubescent males of Sphaeroma serratum enter proecdysis; they reach the D2 stage about 11 to 13 days later; however they remain then blocked at this stage, without leaving their old cuticle, before dying between the Days 10 and 20. The haemolymph of these animals correlatively undergoes variations, similar to those of a normal premolt: raising of calcemia and osmotic pressure, light lowering of the water content; between the stages D2 and D,E an important and sudden lowering of calcemia and osmotic pressure can be observed. At the same time on the contrary, the water content raises only slightly, for the old cuticle sets limits to the increasing volume of the Spherom. After injecting ecdysterone to nonpubescent animals, these leave their cuticle, and their water content raises as much as during a normal exuviation.The exuviation factor (Graf, 1972a and b, C. R. Acad. Sci.274, 1731—1734; 275, 2045–2048) produced by the Y organs (Blanchet, 1974, C. R. Acad. Sci.278, 509–512) would therefore perhaps control only cuticle leaving.  相似文献   

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Parastrongylus cantonensis is a parasite of murid rodents that can infect humans and cause health problems as eosinophilic meningitis. Although it is endemic in south Asia, the Pacific islands, Australia, USA, and a few Caribbean islands, it has been extended to new geographical regions. In the Canary Islands (Spain) a survey of helminths of Rattus rattus, Rattus norvegicus and Mus musculus domesticus was carried out. Furthermore, five species of molluscs were examined for nematode larvae to determine whether they are potential intermediate hosts of P. cantonensis. Nematodes were found in the lungs of 15% of 67 R. rattus examined in Tenerife, one of the four studied islands, with a prevalence of 20% in the highest focus of infection. Based on morphological and molecular analysis, with the complete internal transcribed spacer 2 (ITS-2) and a fragment of the small subunit ribosomal RNA (SSU rRNA) nucleotide sequences, nematodes were identified as P. cantonensis. Larval nematodes found from snails and slugs were identified as third-stage (L3) Metastrongyloidea, but the molecular study showed that they did not belong to P. cantonensis. This is the first finding of angiostrongyliasis in rats in the Canary Islands (Spain). New molecular data for this species and Parastrongylus dujardini are reported. The presence of P. cantonensis in Tenerife could be of importance from the public health point of view. Further studies are required in order to look for other potential foci of infections in the Canary Islands.  相似文献   

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Sergentomyia (Neophlebotomus) monticola, a new species of sand fly (Diptera: Psychodidae), from the Kani tribal settlements, Thiruvananthapuram District, Kerala, southern India was described. These settlements were located in the Western Ghats, which is one of the 25 biodiversity hotspots in the world. Morphological characters of male and female specimens of Sergentomyia (Neophlebotomus) monticola were described with illustrations and its taxonomic position is defined within the genus. The DNA barcode analysis showed that both male and female specimens of the species were belonging to a single taxonomic category. The genetic distance with the most similar taxonomic neighbour was 14.61%, which confirms its distinctness from its congeners. Voucher specimens of the new species were deposited at the museum, Vector Control Research Centre (Indian Council of Medical Research), Puducherry, India, Zoological Survey of India, India and Smithsonian National Museum of Natural History (NMNH), Washington, D.C., USA.  相似文献   

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Summary   Desportesius brevicaudatus (Dujardin, 1845) is redescribed on the basis of light-microscopy and SEM observations on specimens collected from the oesophagus and under the lining of the gizzard of Ixobrychus minutus (Ardeidae) from Bulgaria. New metrical data expand the known ranges of variation of the measurements of the body, tail, cordons, oesophagus and spicules. New information is provided on the variation of the shape of the deirids, the structure of the vagina, the complexity of the cordons, the pattern of the cuticular striation and the shape of the postdeirids. Cordons are described as consisting of a single row of serrate cuticular plates and a longitudinal cuticular ridge along the outer rims of the cuticular plates. The cuticular ridge is interpreted as homologous to the outer row of plates in the cordons of the genera Acuaria, Cheilospirura and Echinuria.  相似文献   

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Summary  The helminth fauna of lungs, small intestine, and rectum of 83 female specimens of Pelophylax kl. esculentus was investigated. Three helminth groups, Trematoda, Nematoda, and Acanthocephala were recorded. The sample was dominated by the class Trematoda. This class was represented by 8 adult and 2 larval species. Opisthioglyphe ranae and Pleurogenoides medians were the dominant fluke species. The data show the occurrence of Acanthocephalus ranae in frogs inhabiting Vojvodina Province. The most frequent Nematoda was Oswaldocruzia filiformis. The greatest number of parasitic species and individuals was isolated from the small intestine. Infestation of individual parasitic groups was greater than that of mixed groups. The most frequent combination was T/N while analysed organs were most frequently invaded by a parasitic species only. Antagonism between genus Rhabdias and Haematoloechus and between species Aplectana acuminata and Opisthioglyphe ranae was ascertained.  相似文献   

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Do Differences Between the Renal and Systemic Circulations Explain the Outcomes Observed With ARBs and ACE Inhibitors?  相似文献   

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The antigen Yk-a is detected in 92 and 98% of the American Caucasian and Negro populations, respectively. In population studies with anti-Yk-a and anti-Cs-a, association was demonstrated between the two antigens; however, in two of three informative families Yk-a and Cs-a segregated independently. The possibility that these antigens have a relationship with leucocyte antigens is discussed.  相似文献   

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Abstract. Serum and eluates known to contain anti-Ata failed to react with El (—) red cells. Conversely, anti-El failed to react with At(a-) red cells. These findings show that the same high-frequency antigen is being recognised by both anti-Ata and anti-El and it is suggested that the name Ata be retained.  相似文献   

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The Asian tiger mosquito Aedes albopictus, vector of various human viruses and parasites, has recently spread and established in many temperate regions including European countries. In the present study, we developed a simple PCR-based assay (the amplification of the internal transcribed spacer ITS2 within nuclear ribosomal rDNA) for molecular identification of A. albopictus and confirmed its presence in Corsica island. This assay may (i) facilitate future large scale studies and avoid misidentifications, especially because of the presence of co-occurring close species in this island and (ii) contribute to the monitoring of A. albopictus populations required for targeted control programs.  相似文献   

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Echinostomatid trematode Echinoparyphium limosorum n. sp. from the charadriiform bird Limosa limosa is described on basis of morphometrical study of museum material. The new species is characterized by medium-sized body up to 4.9 mm long, reniform head collar up to 511 wide, armed with 48–51 collar spines up to 91 μm, arranged in double row. The new species is largely similar to Echinoparyphium recurvatum, however, the most remarkable difference lays in the higher number of collar spines which are 48–51 in E. limosorum n. sp. but 45 in E. recurvatum. The authors discuss relative impact of numerical generic characters and propose an amending of the diagnosis of The genus Echinoparyphium given by Kostadinova (2005) as follows: Collar spines up to 51, sharply pointed, all in double row.  相似文献   

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The IgG and IgM anti-A and anti-B activities from several immune and non-immune O, A and B sera were tested against a panel of weak (A (A3, AX, AND Aend) and weak B (B3 and Bx) red cells. In all cases it is the IgM which agglutinated optimally Ax (or Bx) cells, while IgG and IgM anti-A (or anti-B) reacted similarly with A3 and Aend (or B3) cells. The agglutinating activity of all these ABO antibodies was found straightly related to their association constant for the A (or the B) receptor.  相似文献   

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Syphacia (Seuratoxyuris) hugoti n. sp. (Nematoda: Oxyuridae) is described from the cecum of Sooretamys angouya (Cricetidae: Sigmodontinae: Oryzomyini) captured in Formosa Province, Argentina. The diagnosis of the subgenus is emended, and the new species is separated from eight congeners by the distribution of submedian papillae and amphids, shape of the cephalic plate, presence of deirids, absence of cervical and lateral alae, length of the spicule, structure of the accessory hook of the gubernaculum and distance of excretory pore and vulva from the anterior extremity. The analysis suggests that S. (Se.) oryzomyos should be removed from Seuratoxyuris and redesignated as S. (Syphacia) oryzomyos n. comb. To date, of the species of Syphacia found in South and North American, 7 parasitize Oryzomyini rodents, of which two are distributed in Argentina. The present study constitutes the first record of the subgenus Seuratoxyuris from Argentina and the third record of a Syphacia species from rodents of the tribe Oryzomyini.  相似文献   

20.
Phylogenetic relationships among 21 species of mosquitoes in subgenus Nyssorhynchus were inferred from the nuclear white and mitochondrial NADH dehydrogenase subunit 6 (ND6) genes. Bayesian phylogenetic methods found that none of the three Sections within Nyssorhynchus (Albimanus, Argyritarsis, Myzorhynchella) were supported in all analyses, although Myzorhynchella was found to be monophyletic at the combined genes. Within the Albimanus Section the monophyly of the Strodei Subgroup was strongly supported and within the Myzorhynchella Section Anopheles antunesi and An. lutzii formed a strongly supported monophyletic group. The epidemiologically significant Albitarsis Complex showed evidence of paraphyly (relative to An. lanei-Myzorhynchella) and discordance across gene trees, and the previously synonomized species of An. dunhami and An. goeldii were recovered as sister species. Finally, there was evidence of complexes in several species, including An. antunesi, An. deaneorum, and An. strodei.  相似文献   

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