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1.
The highly polymorphic 60 kDa glycoprotein (GP60) of Cryptosporidium is an important tool for investigating the epidemiology of this parasite. Characterization of the GP60 gene has only been performed for 3 of the 20 known Cryptosporidium species, and has already enabled sub-typing and source tracking of species with human significance. We have characterised a fourth species, Cryptosporidium fayeri, at the GP60 locus using isolates (n = 26) from different marsupial hosts to assess the diversity of GP60 within this species. The analysis demonstrated that C. fayeri isolates could be assigned to 6 subtypes which were associated with host species and locality. The intra-species diversity for the host-adapted C. fayeri was less than the diversity for human pathogenic species suggesting that the GP60 locus is under less selective pressure in these than host-adapted species.  相似文献   

2.
Population genetic studies have been used to understand the transmission of pathogens in humans and animals, especially the role of zoonotic infections and evolution and dispersal of virulent subtypes. In this study, we analysed the genetic diversity and population structure of Cryptosporidium meleagridis, the only known Cryptosporidium species that infects both avian and mammalian hosts and is responsible for approximately 10% of human cryptosporidiosis in some areas. A total of 62 C. meleagridis specimens from children, AIDS patients, and birds in Lima, Peru were characterised by sequence analysis of the ssrRNA gene and five minisatellite, microsatellite and polymorphic markers in chromosome 6, including the 60 kDa glycoprotein (gp60), 47 kDa glycoprotein (CP47), a serine repeat antigen (MSC6-5), retinitis pigmentosa GTPase regulator (RPGR) and thrombospondin protein 8 (TSP8). The multilocus sequence analysis identified concurrent infections with Cryptosporidium hominis in four AIDS patients and three children. Unique subtypes of C. meleagridis ranged from eight at the gp60 locus (gene diversity –Hd = 0.651), three at the RPGR (Hd = 0.556), three at the MSC6-5 locus (Hd = 0.242), two at TSP8 (Hd = 0.198), to one at CP47 (monomorphic), much lower than that of C. hominis in the same area. Intragenic linkage disequilibrium was strong and complete at all gene loci. Intergenic linkage disequilibrium was highly significant (P < 0.001) for all pairs of polymorphic loci. Two major groups of subtypes were seen, with most subtypes belonging to group 1. Within group 1, there was no clear population segregation, and two of the 14 multilocus subtypes of C. meleagridis were found in both AIDS patients and birds. We believe that these results provide the first evidence of a clonal population structure of C. meleagridis and the likely occurrence of cross-species transmission of C. meleagridis between birds and humans.  相似文献   

3.
Cryptosporidium species (apicomplexan protists) are a major cause of diarrhoeal disease (= cryptosporidiosis) in humans worldwide. The impact of cryptosporidiosis is also compounded by the spread of HIV/AIDS and a lack of cost-effective anti-cryptosporidial chemotherapeutics or vaccines. Mitigation of the impact of cryptosporidiosis in humans needs to focus on prevention and control strategies, built on a sound understanding of the epidemiology of Cryptosporidium species. Refined epidemiological studies rely on the use of molecular tools employing informative genetic markers. Currently, the 60-kDa glycoprotein gene (gp60) is the most suitable and widely used genetic marker for Cryptosporidium species infecting humans. Here, we undertake an analysis of all publicly-available gp60 sequence data and associated literature for C. hominis and C. parvum, and yield useful insights into the richness, diversity and distribution of genetic variants, and link these variants to human cryptosporidiosis. This global analysis reveals that, despite high genetic richness in Cryptosporidium isolates from humans, there is a surprisingly low diversity. It also highlights limited knowledge about the genetics of cryptosporidiosis in developing nations and in many animals that might act as infection sources. Clearly, there is a major need for more comprehensive studies of Cryptosporidium infecting humans and other animals in Africa and Asia. As molecular technologies improve and become affordable, future studies should utilize “next generation” sequencing and bioinformatic platforms to conduct comparative ‘genome sequence surveys’ to test the validity of current genetic classifications based on gp60 data. Complemented by in vitro and in vivo investigations, these biotechnological advances will also assist significantly in the search for new intervention strategies against human cryptosporidiosis.  相似文献   

4.
Non-human primates (NHPs) are commonly infected with Cryptosporidium spp. and Giardia duodenalis. However, molecular characterisation of these pathogens from NHPs remains scarce. In this study, 2,660 specimens from 26 NHP species in China were examined and characterised by PCR amplification of 18S rRNA, 70 kDa heat shock protein (hsp70) and 60 kDa glycoprotein (gp60) gene loci for Cryptosporidium; and 1,386 of the specimens by ssrRNA, triosephosphate isomerase (tpi) and glutamate dehydrogenase (gdh) gene loci for Giardia. Cryptosporidium was detected in 0.7% (19/2660) specimens of four NHP species including rhesus macaques (0.7%), cynomolgus monkeys (1.0%), slow lorises (10.0%) and Francois’ leaf monkeys (6.7%), belonging to Cryptosporidium hominis (14/19) and Cryptosporidium muris (5/19). Two C. hominis gp60 subtypes, IbA12G3 and IiA17 were observed. Based on the tpi locus, G. duodenalis was identified in 2.2% (30/1,386) of specimens including 2.1% in rhesus macaques, 33.3% in Japanese macaques, 16.7% in Assam macaques, 0.7% in white-headed langurs, 1.6% in cynomolgus monkeys and 16.7% in olive baboons. Sequence analysis of the three targets indicated that all of the Giardia-positive specimens belonged to the zoonotic assemblage B. Highest sequence polymorphism was observed at the tpi locus, including 11 subtypes: three known and eight new ones. Phylogenetic analysis of the subtypes showed that most of them were close to the so-called subtype BIV. Intragenotypic variations at the gdh locus revealed six types of sequences (three known and three new), all of which belonged to so-called subtype BIV. Three specimens had co-infection with C. hominis (IbA12G3) and G. duodenalis (BIV). The presence of zoonotic genotypes and subtypes of Cryptosporidium spp. and G. duodenalis in NHPs suggests that these animals can potentially contribute to the transmission of human cryptosporidiosis and giardiasis.  相似文献   

5.
Two house mouse subspecies occur in Europe, eastern and northern Mus musculus musculus (Mmm) and western and southern Mus musculus domesticus (Mmd). A secondary hybrid zone occurs where their ranges meet, running from Scandinavia to the Black Sea. In this paper, we tested a hypothesis that the apicomplexan protozoan species Cryptosporidium tyzzeri has coevolved with the house mouse. More specifically, we assessed to what extent the evolution of this parasite mirrors divergence of the two subspecies. In order to test this hypothesis, we analysed sequence variation at five genes (ssrRNA, Cryptosporidium oocyst wall protein (COWP), thrombospondin-related adhesive protein of Cryptosporidium 1 (TRAP-C1), actin and gp60) in C. tyzzeri isolates from Mmd and Mmm sampled along a transect across the hybrid zone from the Czech Republic to Germany. Mmd samples were supplemented with mice from New Zealand. We found two distinct isolates of C. tyzzeri, each occurring exclusively in one of the mouse subspecies (C. tyzzeri-Mmm and C. tyzzeri-Mmd). In addition to genetic differentiation, oocysts of the C. tyzzeri-Mmd subtype (mean: 4.24 × 3.69 μm) were significantly smaller than oocysts of C. tyzzeri-Mmm (mean: 4.49 × 3.90 μm). Mmm and Mmd were susceptible to experimental infection with both C. tyzzeri subtypes; however, the subtypes were not infective for the rodent species Meriones unguiculatus, Mastomys coucha, Apodemus flavicollis or Cavia porcellus. Overall, our results support the hypothesis that C. tyzzeri is coevolving with Mmm and Mmd.  相似文献   

6.

Background

Polyunsaturated fatty acids (PUFAs) have antifungal properties, but the mode by which they induce their action is not always clear. The aim of the study was to investigate apoptosis as a mode of action of antifungal PUFAs (stearidonic acid, eicosapentaenoic acid and docosapentaenoic acid) which are inhibitory towards biofilm formation of C. albicans and C. dubliniensis.

Methods

Candida biofilms were grown in the absence or presence of 1 mM PUFAs (linoleic acid, stearidonic acid, eicosapentaenoic acid, docosapentaenoic acid) for 48 h at 37 °C. The effect of these PUFAs on the membrane fatty acid profile and unsaturation index, oxidative stress, mitochondrial transmembrane potential and apoptosis was evaluated.

Results

When biofilms of C. albicans and C. dubliniensis were exposed to certain PUFAs there was an increase in unsaturation index of the cellular membranes and accumulation of intracellular reactive oxygen species (ROS). This resulted in apoptosis, evidenced by reduced mitochondrial membrane potential and nuclear condensation and fragmentation. The most effective PUFA was stearidonic acid.

Conclusions

The resultant cell death of both C. albicans and C. dubliniensis is due to apoptosis.

General significance

Due to the increase in drug resistance, alternative antifungal drugs are needed. A group of natural antifungal compounds is PUFAs. However, understanding their mechanisms of action is important for further use and development of these compounds as antifungal drugs. This paper provides insight into a possible mode of action of antifungal PUFAs.  相似文献   

7.
Two species belonging to the genus Salvia (Salvia brachyodon Vandas and Salvia officinalis L.) from Dalmatian region were studied for their essential oil composition, genome size and base composition. These species showed the same chromosome number (2n = 14), similar genome size (0.95 and 0.97 pg/2C) and base composition (38.52 and 38.55 GC%), respectively. This is the first estimation of DNA content and base composition for both species.  相似文献   

8.
Several molecular methods have been employed for Borrelia species identification. Newly developed technology, real-time polymerase chain reaction (RT-PCR), combines simultaneous amplification, detection and differentiation of strains in one PCR run. The aim of the study was to perform and evaluate RT-PCR for Borreliaburgdorferi sensu lato species identification. Borrelia species identification was accomplished on 374 Borrelia strains using two approaches: 1.) MluI restriction of entire borrelial chromosome (MluI-large restriction fragment patterns, LRFP), and 2.) RT-PCR targeting hbb gene and specific melting temperature (Tm) detection. The results of the two molecular methods were compared. With MluI-RFLP we were able to differentiate all Borrelia species and their subtypes within particular species. RT-PCR based on Tm determination identified unique strains within the species Borreliaafzelii (Tm 66.11 °C), B. burgdorferi sensu stricto (Tm 68.18 °C), Borreliaspielmanii (Tm 59.45 °C) and Borreliavalaisiana (Tm 59.62 °C). We were not able to distinguish the last two species that shared almost identical Tm. The large majority of Borreliagarinii strains shared Tm 51.42 °C, while subtype Mlg4 was characterized by Tm 56.87 °C. Strains of Borrelialusitaniae species also were heterogeneous; human isolate had Tm 63.47 °C while two tick isolates shared Tm 61.77 °C. Differences inside hbb gene enabled differentiation of the majority of Borrelia species, and revealed two clusters within B. garinii and B. lusitaniae species, respectively, but it was not possible to distinguish B. spielmanii form B. valaisiana. The major advantage of RT-PCR was that it was easy to perform and that the results were obtained within a few hours.  相似文献   

9.
An external quality assessment (EQA) panel consisting of a total of 13 samples in broncho alveolar lavage (BAL) or transport medium was prepared to assess the proficiency of laboratories in the correct detection of Chlamydophila pneumoniae and Mycoplasma pneumoniae by nucleic acid amplification techniques (NAATs) (6 samples containing various concentrations (4.9-490 inclusion forming units (IFU)/ml) of C. pneumoniae, 5 samples containing various concentrations (20-5000 color-changing units (CCU)/ml) of M. pneumoniae and 2 samples negative for both).Seventy-nine laboratories from 18 countries participated in this EQA study. Sixty-four datasets were returned for C. pneumoniae (n = 5 conventional commercial, n = 10 conventional in-house, n = 4 real-time commercial, n = 43 real-time in-house, and n = 2 SDA). Sixty-seven datasets were obtained for M. pneumoniae (n = 5 conventional commercial, n = 10 conventional in-house, n = 4 real-time commercial, n = 46 real-time in-house, and n = 2 strand displacement amplification (SDA)). For the total panels, correct results per sample varied between 95.3% and 100% for C. pneumoniae and between 53.7% and 95.5% for M. pneumoniae. In general, commercial conventional NAATs showed possible sensitivity issues when compared to conventional in-house NAATs for both organisms. On the other hand, real-time commercial NAATs scored better than real-time in-house assays in terms of sensitivity for both organisms. For C. pneumoniae and M. pneumoniae, 0.8% and 2.2% true false-positive results and 1.9% and 2.0% false positives were reported in the samples spiked with the other organism.Analysis of the data for C. pneumoniae showed that the concentrations used were easily detectable by the vast majority of participants. The percentage of correct qualitative results for M. pneumoniae demonstrated that the concentrations included in this panel proved challenging for a number of participants.  相似文献   

10.
Apart from a single record in a shark, there have been no published studies conducted on Giardia genotypes in fish. The present study investigated the prevalence of Giardia in cultured fingerlings (= 227), wild freshwater (n = 227) and wild marine/estuarine species (n = 255) of fish in Western Australia by PCR amplification at the 18S rRNA, glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi) and beta-giardin (bg) loci. Results revealed a low prevalence of Giardia, 3.8% (27/709), in fish hosts. The zoonotic Giardia species, Giardia duodenalis assemblages A, B as well as G. duodenalis assemblage E and Giardia microti were detected. The identification of zoonotic species of Giardia highlights the public health importance of investigating parasites within fish host species.  相似文献   

11.
Four red-pigmented isolates, with optimum growth temperatures of approximately 55–60 °C and an optimum pH for growth between 7.5 and 8.5, were recovered from hot springs in Central France. Phylogenetic analysis of the 16S rRNA gene sequences showed that these organisms represented a new species of the genus Meiothermus. The new isolates could be distinguished from other strains of the species of the genus Meiothermus primarily by the glycolipid profile and fatty acid composition because these organisms lacked the hydroxy fatty acids and the glycolipid variant GL-1a found in all other isolates of the species of Meiothermus examined. On the basis of the results presented here we propose the name Meiothermus rufus for the new species, which is represented by strains CAL-4T (=DSM 22234T=LMG 24878T) and CAL-12 (=DSM 22235=LMG 24879). We also propose emending the genus Meiothermus to include strains that have only one glycolipid instead of two glycolipid variants.  相似文献   

12.
Knowledge of the social structure of a population is important for a range of fundamental and applied purposes. Group characteristics and population structure of chital (Axis axis) and sambar (Rusa unicolor) were studied in a deciduous habitat of Mudumalai Tiger Reserve, Western Ghats, India, during 2008-2009. Vehicle transects were monitored monthly to gather information on group-size and age-sex composition of chital and sambar. The average mean group size and crowding for chital and sambar was 13.1 ± 0.5 (n = 1020), 3.6 ± 0.2 (n = 377) and 33.3, 11.0 respectively. The average adult male:adult female:fawn ratio was 63.4:100:22.3 (n = 9391) and 43.9:100:23.7 (n = 1023) in chital and sambar respectively. The mean group size of chital and sambar varied significantly between seasons (Kruskal-Wallis test, p = <0.001). Peak fawning season was observed from February to May for chital and May to August for sambar. Group's sex-age composition influenced group formation in both species between seasons at different level. Adult male and fawn were the important predicting variables of change in group size. Skewed female sex ratio was probably due to selective male predation by large predators. Although fawning occurred throughout the year, both species showed seasonality in fawning. The above mentioned patterns differed between species depending upon their ecological adaptation in foraging strategies and habitat preference.  相似文献   

13.
Chemical implantation of Group 4 cations [Ti(III), Ti(IV), Zr(IV), Hf(IV)] has been carried out under mild conditions by the reaction of polycyclopentadienyl- (MCpn; M = Ti, n = 3, 4; M = Zr, Hf, n = 4), mixed cyclopentadienyl/N,N-dialkylcarbamato (MLx(O2CNEt2)y; M = Ti, L = Cp, C5Me5 (Cp*), x = 2, y = 1; M = Hf, L = Cp, x = 1, y = 3), and N,N-dialkylcarbamato (M(O2CNR2)n, M = Ti, n = 3, R = iPr; M = Ti, Hf, n = 4, R = Et; M = Zr, n = 4, R = iPr) derivatives, with the silanol groups of amorphous silica. Cyclopentadiene/pentamethylcyclopentadiene and/or carbon dioxide and the secondary amine are released in the process. The amount of implanted cations depends on the metal and on the ligands, the pentamethylcyclopentadienyl complex being less reactive than the unsubstituted congener. The starting complexes and the final products have been characterized by EPR or by 13C CP-MAS NMR spectroscopy.  相似文献   

14.
15.
In this study, we have investigated the association between osteoporosis and osteocalcin (BGLAP) − 298 C>T, estrogen receptor 1 (ER1) 397 T>C, collagen type1 alpha 1 (Col1A1) 2046 G>T and calcitonin receptor (CALCR) 1340 T>C polymorphisms. Genomic DNA was obtained from 266 persons (158 osteoporotic and 108 healthy controls). Genomic DNA was extracted from EDTA-preserved peripheral venous blood of patients and controls by a salting-out method and analyzed by PCR-RFLP. As a result, there was no statistically significant difference in the genotype and allele frequencies of patients and controls for BGLAP − 298 C>T, Col1A1 2046 G>T, ER1 397 T>C and CALCR 1340 T>C polymorphisms. However, ER1 CC genotype compared with TT + TC genotypes was found to increase the two fold the risk of osteoporosis [p = 0.039, OR = 2.156, 95% CI (1.083–4.293)] and CALCR CC genotype compared with TT + TC genotypes was found to have protective effect against osteoporosis [p = 0.045, OR = 0.471, 95% CI (0.237–0.9372)]. In the combined genotype analysis, ER1/CALCR TCCC combined genotype was estimated to have protective effect against osteoporosis [p = 0.0125, OR = 0.323, 95% CI (0.1383–0.755)] whereas BGLAP/Col1A1 CCTT and ER1/CALCR CCTT combined genotypes were estimated as risk factors for osteoporosis in Turkish population (p = 0.027, p = 0.009 respectively).  相似文献   

16.
Gram-negative, facultatively anaerobic bacteria were isolated from symptomatic oak tissue in the UK and USA. Partial gyrB sequencing placed ten strains in the genus Brenneria, with B. goodwinii as the closest phylogenetic relative. The strains were investigated further using a polyphasic approach including MLSA (based on partial gyrB, rpoB, infB and atpD gene sequences), 16S rRNA gene sequencing, DNA–DNA relatedness studies and both phenotypic and chemotaxonomic assays. The MLSA and 16S rRNA gene analyses separated the strains into two groups based on origin, suggesting that they belong to Brenneria as two novel species. However, the DNA–DNA relatedness values revealed a closer relationship between the groups and indicated that they should belong to the same species. As the two groups of strains from the UK and USA can be differentiated from each other phenotypically and by ERIC PCR fingerprints, it is proposed to classify them as novel subspecies of a novel Brenneria species. The name Brenneria roseae sp. nov. (FRB 222T = LMG 27714T = NCPPB 4581T) is proposed, with Brenneria roseae subsp. roseae ssp. nov. (FRB 222T = LMG 27714T = NCPPB 4581T) for the strains from the UK and Brenneria roseae subsp. americana ssp. nov. (FRB 223T = LMG 27715T = NCPPB 4582T) for the strains from the USA.  相似文献   

17.
Two red-pigmented isolates, with optimum growth temperatures between 45 and 50 °C, were recovered from a hot spring in the Furnas, Área da Fonte 1825 on the Island of São Miguel in the Azores. Phylogenetic analysis of the 16S rRNA gene sequences showed that these organisms represented a new species of the genus Meiothermus. These new isolates could be distinguished from other strains of the species of the genus Meiothermus primarily by the fatty acid composition and polar lipid pattern, since they did not possess 2-OH fatty acids or glycolipid variant GL-1a. Moreover, the two new isolates had the lowest growth temperature range of any of the known species of the genus Meiothermus. On the basis of the results presented here we propose the name Meiothermus granaticius for the new species represented by strains AF-68T (=DSM 23260T = LMG 25524T) and AF-49 (=DSM 23259 = LMG 25525).  相似文献   

18.
Two Gram-staining-negative, moderately halophilic bacteria, strains M1-18T and L1-16, were isolated from a saltern located in Huelva (Spain). They were motile, strictly aerobic rods, growing in the presence of 3–25% (w/v) NaCl (optimal growth at 7.5–10% [w/v] NaCl), between pH 4.0 and 9.0 (optimal at pH 6.0–7.0) and at temperatures between 15 and 40 °C (optimal at 37 °C). Phylogenetic analysis based on 16S rRNA gene sequence comparison showed that both strains showed the higher similarity values with Chromohalobacter israelensis ATCC 43985T (95.2–94.8%) and Chromohalobacter salexigens DSM 3043T (95.0–94.9%), and similarity values lower than 94.6% with other species of the genera Chromohalobacter, Kushneria, Cobetia or Halomonas. Multilocus sequence analysis (MLSA) based on the partial sequences of atpA, rpoD and secA housekeeping genes indicated that the new isolates formed an independent and monophyletic branch that was related to the peripheral genera of the family Halomonadaceae, Halotalea, Carnimonas and Zymobacter, supporting their placement as a new genus of the Halomonadaceae. The DNA–DNA hybridization between both strains was 82%, whereas the values between strain M1-18T and the most closely related species of Chromohalobacter and Kushneria were equal or lower to 48%. The major cellular fatty acids were C18:1ω7c/C18:1ω6c, C16:0, and C16:1ω7c/C16:1ω6c, a profile that differentiate this new taxon from species of the related genera. We propose the placement of both strains as a novel genus and species, within the family Halomonadaceae, with the name Larsenia salina gen. nov., sp. nov. The type strain is M1-18T (= CCM 8464 = CECT 8192T = IBRC-M 10767T = LMG 27461T).  相似文献   

19.
20.
Two newly isolated halotolerant obligately methylotrophic bacteria (strains C2T and SK12T) with the serine pathway of C1 assimilation are described. The isolates are strictly aerobic, Gram negative, asporogenous, non-motile rods, forming rosettes, multiplying by binary fission. Mesophilic and neutrophilic, accumulate intracellularly compatible solute ectoine and poly-β-hydroxybutyrate. The novel strains are able to grow at 0 up to 16% NaCl (w/v), optimally at 3–5% NaCl. The major cellular fatty acids are C18:1ω7c and C19:0cyc and the prevailing quinone is Q-10. The predominant phospholipids are phosphatidylcholine, phosphatidylglycerol, phosphatidyldimethylethanolamine and phosphatidylethanolamine. Assimilate NH4+ by glutamate dehydrogenase and via the glutamate cycle (glutamine synthetase and glutamate synthase). The DNA G + C contents of strains C2T and SK12T are 60.9 and 60.5 mol% (Tm), respectively. 16S rRNA gene sequence similarity between the two new isolates are 99% but below 94% with other members of the Alphaproteobacteria thus indicating that they can be assigned to a novel genus Methyloligella. Rather low level of DNA–DNA relatedness (53%) between the strains C2T and SK12T indicates that they represent two separate species of the new genus, for which the names Methyloligella halotolerans gen. nov., sp. nov. and Methyloligella solikamskensis sp. nov. are proposed. The type strain of Methyloligella halotolerans is C2T (=VKM B-2706T = CCUG 61687T = DSM 25045T) and the type strain of Methyloligella solikamskensis is SK12T (=VKM B-2707T = CCUG 61697T = DSM 25212T).  相似文献   

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