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1.
Galba truncatula snails were experimentally infected with either of two different isolates of Fasciola gigantica, originating from Egypt or China, to determine the influence of these isolates on the characteristics of snail infections. The survival rates of G. truncatula on day 30 post-exposure were 90.0% and 60.2% in the Egyptian and Chinese groups, respectively. The frequency of cercaria-shedding snails within the Egyptian group was 79.8%, whereas in the Chinese group it was 22.4%. The parasite origin had a significant effect on the durations of the prepatent and patent periods. The mean number of cercariae shed from the Egyptian group was significantly greater than that shed from the Chinese group (a mean of 275.5 per cercaria-shedding snail compared with 29.0). These results could be explained by the fact that G. truncatula might be a natural intermediate host for F. gigantica in Egypt, and the greater adaptability of the Egyptian miracidia of F. gigantica to unusual snail hosts. These results demonstrate the influence of the geographic origin of the parasite on the success of trematodes infecting snails. 相似文献
2.
Karina?M.?Rebello Luzia?M.?C.?C?rtes Bernardo?A.?S.?Pereira Bernardo?M.?O.?Pascarelli Suzana?C?rte-Real Léa?C.?Finkelstein Rosa?T.?Pinho Claudia?M.?d’Avila-Levy Carlos?R.?Alves 《Parasitology research》2009,106(1):95-104
Leishmania (Viannia) braziliensis is the major causative agent of American tegumentary leishmaniasis, a disease that has a wide geographical distribution and
is a severe public health problem. The cysteine proteinase B (CPB) from Leishmania spp. represents an important virulence factor. In this study, we characterized and localized cysteine proteinases in L. (V.) braziliensis promastigotes. By a combination of triton X-114 extraction, concanavalin A-affinity, and ion exchange chromatographies, we
obtained an enriched fraction of hydrophobic proteins rich in mannose residues. This fraction contained two proteinases of
63 and 43 kDa, which were recognized by a CPB antiserum, and were partially sensitive to E-64 in enzymatic assays with the
peptide Glu-Phe-Leu. In confocal microscopy, the CPB homologues localized in the peripheral region of the parasite. This data
together with direct agglutination and flow cytometry assays suggest a surface localization of the CPB homologues. The incubation
of intact promastigotes with phospholipase C reduced the number of CPB-positive cells, while anti-cross-reacting determinant
and anti-CPB antisera recognized two polypeptides (63 and 43 kDa) derived from phospholipase C treatment, suggesting that
some CPB isoforms may be glycosylphosphatidylinositol-anchored. Collectively, our results suggest the presence of CPB homologues
in L. braziliensis surface and highlight the need for further studies on L. braziliensis cysteine proteinases, which require enrichment methods for enzymatic detection. 相似文献
3.
Mes [Vet Parasitol (2003) 115:311–320] recently reported a quantitative study of repeated measurements of nematode egg counts in faecal samples from dairy cattle, in order to compare the faecal egg counts resulting from two different laboratory techniques, the widely used McMaster method and a newer salt-sugar flotation (SSF) method. He concluded that the SSF technique requires much smaller sample sizes, and is also potentially simpler to carry out, making it the method of choice. Here I re-analyse these data to show that if the comparison is done on the most appropriate measurement scale (lognormal), and the large difference in multiplication factors is taken into account, then there is little to choose between the McMaster and SSF techniques as far as the required sample size is concerned. In particular, the treatment of the data as normally rather than lognormally distributed leads to incorrect statistical tests, power analyses and confidence intervals. 相似文献
4.
5.
Yellow oat-grass plants (Trisetum flavescens L.) with mild mosaic and pronounced dwarfing symptoms were observed at different locations in the Czech Republic. Electron
microscope observations of symptomatic plants revealed the presence of filamentous particles and inclusion bodies characteristic
of the family Potyviridae. The virus was readily mechanically transmitted to its original host plus a narrow host range of monocot species. Serological
assays of infected plant extracts using antiserum specific to the closest species in the family Potyviridae were negative. The 3′ end of the viral genome was cloned, sequenced and compared to sequences of species in the family Potyviridae. The virus is more closely related to viruses in the genus Tritimovirus than to other genera within the Potyviridae. Based on phylogenetic analyses of the coat protein cistron and flanking genomic regions, we propose this is a distinct viral
species of the genus Tritimovirus, tentatively named Yellow oat-grass mosaic virus (YOgMV). 相似文献
6.
Cryptosporidium molnari was experimentally transmitted to gilthead sea bream (Sparus aurata) and European sea bass (Dicentrachus labrax) by oral infection with infected stomach scrapings. The infection was also cross-transmitted from infected gilthead sea bream to sea bass by cohabitation. The course of the infection was assessed after necropsy by three microscopic diagnostic methods and their sensitivity was compared. At the end of all the experiments the prevalence of infection reached 100%. In the oral experiments, both fish hosts appeared infected as early as 7 days post exposure (p.e.), but gilthead sea bream exhibited a higher intensity of infection and infection proceeded at a faster rate than in sea bass. The cellular host reaction was stronger in sea bass than in sea bream, whereas the histopathological effect was lower in the former. Transmission could be favoured by cannibalism among cohabiting fish. This is the first report on piscine Cryptosporidium transmission. The implications for the aquaculture industry are discussed. 相似文献
7.
Summary. The nucleotide sequences of the 3 terminal region of the genomes of Alstroemeria mosaic virus (AlsMV) and the Amazon lily mosaic virus (ALiMV) have been determined. These sequences contain the complete coding region of the viral coat protein (CP) gene followed by a 3-untranslated region (3-UTR). AlsMV and ALiMV share 74.9% identity in the amino acid sequence of the CP, and 55.6% identity in the nucleotide sequence of the 3-UTR. Phylogenetic analysis of these CP genes and 3-UTRs in relation to those of 79 potyvirus species revealed that AlsMV and ALiMV should be assigned to the Potato virus Y (PVY) subgroup. AlsMV and ALiMV were concluded to have arisen independently within the PVY subgroup. 相似文献
8.
María del Rosario Robles James E. Loudon John M. Kinsella Mandala Hunter-Ishikawa David S. Miller Michelle L. Sauther Frank P. Cuozzo 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2010,55(3):270-275
Lemuricola (Madoxyuris) bauchoti Chabaud, Brygoo et Petter, 1965 is redescribed from material collected from the ring-tailed lemur, Lemur catta, from the Beza Mahafaly Special Reserve in Madagascar using the scanning electron microscope. This is a new host record and
the first oxyurid reported from the ring-tailed lemur. Previously, records of each species of the subgenus Madoxyuris have been restricted to a single host species, but the close relationship between these nematodes and their Strepsirrhini
hosts will only be proven when additional records fill in the gaps in their distribution. 相似文献
9.
10.
Santoro GF das Graças Cardoso M Guimarães LG Salgado AP Menna-Barreto RF Soares MJ 《Parasitology research》2007,100(4):783-790
In the present work, we have investigated the effect of essential oils obtained from Origanum vulgare L. (oregano) and Thymus vulgaris L. (thyme) on growth and ultrastructure of diverse evolutive forms of Trypanosoma cruzi. Culture epimastigotes and bloodstream trypomastigotes were incubated for 24 h with different concentrations of oregano or
thyme essential oils and with thymol (the main constituent of thyme), and the inhibitory concentration (IC)50 was determined by cell counting. Crude extract of oregano essential oil inhibited epimastigote growth (IC50/24 h = 175 μg/ml) and also induced trypomastigote lysis (IC50/24 h = 115 μg/ml). Thyme essential oil presented IC50/24 h values of 77 μg/ml for epimastigotes and 38 μg/ml for trypomastigotes, while treatment with thymol resulted in an IC50/24 h of 62 μg/ml for epimastigotes and 53 μg/ml for trypomastigotes. Scanning electron microscopy of treated cells showed
few morphological alterations at the plasma membrane. Observation by transmission electron microscopy showed cytoplasmic swelling
with occasional morphological alterations in plasma and flagellar membrane. Our data indicate that oregano and thyme essential
oils are effective against T. cruzi, with higher activity of thyme, and that thymol may be the main component responsible for the trypanocidal activity. 相似文献
11.
Virus isolate T217L was obtained from a diseased tomato (Solanum lycopersicum) plant showing leaf deformation and chlorotic mottle symptoms near Maracaibo in the state of Zulia, Venezuela. Full-length
DNA-A and DNA-B molecules of T217L were cloned and sequenced. The genome organization of T217L was identical to the bipartite
genomes of other begomoviruses described from the Americas. Characteristic disease symptoms were reproduced in S. lycopersicum and Capsicum annum plants inoculated using the cloned viral DNA-A and DNA-B components, confirming disease aetiology. A sequence analysis of
DNA-A showed that the T217L isolate has the highest sequence identity (84%) with sida yellow mosaic Yucatan virus (SiYMYuV),
sida golden mosaic Honduras virus (SiGMHV) and bean dwarf mosaic virus (BDMV) isolates. This is less than the 89% identity
in the DNA-A component that has been defined as the threshold value for the demarcation of species in the genus Begomovirus. The molecular data show that isolate T217L belongs to a novel tentative begomovirus species, for which the name tomato chlorotic
leaf distortion virus is proposed. TCLDV was also detected in symptomatic C. chinense plants growing near the T217L-infected plant. 相似文献
12.
The outlying mean index (OMI) method was used to test for seasonal microhabitat partitioning in Pseudodactylogyrus anguillae and Pseudodactylogyrus bini communities parasitising European eel ( Anguilla anguilla L.) in four seasons. No differences in the occurrence of parasites were found in different seasons or on different gill arches. The OMI analysis showed that hemibranch separation and gill segments were the main factors explaining the variation in parasite niche occupation for the first factorial axis, which was generally more significant than the second factorial axis. The OMI and tolerance indices were compared for both species in the seasons studied, and the main differences between species indices were recorded. P. anguillae and P. bini communities were partitioned in the seasons with high epidemiological parameters of the infection. In the seasons with low epidemiological parameters, or in seasons when the parasite species preferred gill arches, the characters of gill division (lower level of gill division than gill arches) were not important for the partitioning of the Pseudodactylogyrus communities. 相似文献
13.
Adriana García-Vásquez Haakon Hansen Kevin W. Christison James E. Bron Andrew P. Shinn 《Acta parasitologica / Witold Stefański Institute of Parasitology, Warszawa, Poland》2011,56(1):20-33
Three new species of Gyrodactylus are described from two species of Oreochromis (Cichlidae): Gyrodactylus hildae sp. nov. from the Nile tilapia, Oreochromis niloticus niloticus, and from an unconfirmed cichlid in Ethiopia; Gyrodactylus ulinganisus sp. nov. from a South African population of Mozambique tilapia, Oreochromis mossambicus; and, Gyrodactylus yacatli sp. nov. from O. n. niloticus reared in Mexico. The hamuli and marginal hooks of G. hildae sp. nov. and G. yacatli sp. nov. differ notably from G. cichlidarum, a species commonly found on O. n. niloticus. The hooks of G. ulinganisus sp. nov., however, are morphologically similar to those of G. cichlidarum, but the two species were found to differ by 42 nucleotide substitutions (24 within the 342 bp long ITS1; 18 within the 303
bp long ITS2) and by 1 insertion/deletion. This study confirms that Nile and Mozambique tilapia harbour a number of different
species of Gyrodactylus, with G. cichlidarum being the most frequently encountered and being associated with mortalities of juvenile O. n. niloticus. This study discusses the host specificity of gyrodactylids on commercial cichlid species and the potential repercussions
of their movement on stocks of fish into new environments where cichlids are already present. 相似文献
14.
Edílson Damke Joyce K Tsuzuki Diógenes AG Cortez Izabel CP Ferreira Thâmara A Bertoni Márcia R Batista Lucélia Donati Terezinha IE Svidzinski Márcia EL Consolaro 《BMC complementary and alternative medicine》2011,11(1):35
Background
Study of in vivo antifungal activity of the hydroalcoholic extract (HE) and n-BuOH extract (BUTE) of Sapindus saponaria against azole-susceptible and -resistant human vaginal Candida spp. 相似文献15.
Pepo aphid-borne yellows virus (PABYV) has been proposed as a putative representative of a new species in the genus Polerovirus in the family Luteoviridae. The genomes of two South African (SA) isolates of cucurbit-infecting PABYV were described in this record. Total RNA, extracted from a pattypan (Cucurbita pepo L.) and a baby marrow (C. pepo L.) leaf samples, was subjected to next-generation sequencing (NGS) on the HiSeq Illumina platform. Sanger sequencing was subsequently used to authenticate the integrity of PABYV’s genome generated from de novo assembly of the NGS data. PABYV genome of SA isolates consists of 5813 nucleotides and displays an organisation typical of poleroviruses. Genome sequence comparisons of the SA PABYV isolates to other poleroviruses support the classification of PABYV as a new species in the genus Polerovirus. Recombination analyses showed that PABYV and Cucurbit aphid-borne yellows virus (CABYV) shared the same ancestor for the genome part situated between breaking points. Phylogenetic analyses of the RNA-dependent RNA polymerase and the coat protein genes showed that SA PABYV isolates shared distant relationship with CABYV and Suakwa aphid-borne yellows virus. Based on our results, we propose that PABYV is a distinct species in the genus Polerovirus. 相似文献
16.
Passero LF Carvalho AK Bordon ML Bonfim-Melo A Toyama MH Corbett CE Laurenti MD 《Inflammation research》2012,61(3):255-263
Objective
Leishmania (Viannia) shawi was characterized only recently, and few studies concerning the immunogenic and protective properties of its antigens have been performed. The present study aimed to evaluate the protective potential of the five antigenic fractions isolated from L. (V.) shawi promastigotes in experimental cutaneous leishmaniasis. 相似文献17.
All trypanosome species classified in the subgenus Herpetosoma in sciurid hosts have been recorded from ground and tree squirrels to date, but not from any flying squirrels. We describe in this paper a novel trypanosome species, Trypanosoma (Herpetosoma) kuseli sp. n., from Siberian flying squirrels (Pteromys volans) imported from China, and compare it with T. (H.) otospermophili in Richardson's ground squirrels (Spermophilus richardsonii) and Columbian ground squirrels (Spermophilus columbianus) from the USA. Due to a short free flagellum, the new species appeared stumpy compared with T. otospermophili (length of free flagellum 7.0 +/- 0.8 microm, total length 32.1 +/- 0.8 microm, n = 13 and length of free flagellum 15.5 +/- 1.6 microm, total length 35.9 +/- 1.0 microm, n = 13, respectively). Another conspicuous morphological feature of the new species was an anteriorly positioned kinetoplast, found approximately at the midpoint between the nucleus and the posterior end. These characters have not been recorded from any squirrel Herpetosoma trypanosome species. Comparison of the nucleotide sequences of the small and large subunit rRNA genes indicated that T. kuseli sp. n. was more homologous to T. otospermophili than murid Herpetosoma species, such as T. grosi, T. lewisi, T. musculi, T. microti and T. evotomys. 相似文献
18.
Silva-Lopez RE Morgado-Díaz JA Alves CR Côrte-Real S Giovanni-De-Simone S 《Parasitology research》2004,93(4):328-331
Extracellular proteolytic activity was detected in a Leishmania (L.) amazonensis culture supernatant and a 56-kDa protein was purified using (NH4)2SO4 precipitation followed by affinity chromatography on aprotinin–agarose. A rabbit serum obtained against the 56-kDa extracellular serine protease was used in order to analyze its location in L. (L.) amazonensis parasites. Immunocytochemistry studies revealed that the enzyme is mainly found in the flagellar pocket and cytoplasmic vesicles of promastigote forms, whereas in amastigotes, it is located in electron-dense structures resembling megasomes. These results indicate that the 56-kDa serine protease is released into the extracellular environment through the flagellar pocket; and its intracellular location suggests either a correlated enzymatic activity or intracellular trafficking. 相似文献
19.
Ivanov PA Mukhamedzhanova AA Smirnov AA Rodionova NP Karpova OV Atabekov JG 《Virus genes》2011,42(2):268-271
A southeastern European isolate of Alternanthera mosaic virus (AltMV-MU) of the genus Potexvirus (family Flexiviridae) was purified from the ornamental plant Portulaca grandiflora. The complete nucleotide sequence (6606 nucleotides) of AltMV-MU genomic RNA was defined. The AltMV-MU genome is different
from those of all isolates described earlier and is most closely related to genomes of partly sequenced portulaca isolates
AltMV-Po (America) and AltMV-It (Italy). Phylogenetic analysis supports the view that AltMV-MU belongs to a new “portulaca”
genotype distinguishable from the “phlox” genotype. 相似文献
20.
Weihuan Huang Xiaoli Zhang Yifei Wang Wencai Ye Vincent EC Ooi Hau Yin Chung Yaolan Li 《Chinese medicine》2010,5(1):23