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1.
The genus Fusarium hosts a large number of economically significant phytopathogens with a global distribution. Surprisingly, only a limited number of studies have tried to identify the natural distribution of members of this genus in undisturbed soils. Members of the Fusarium incarnatum-equiseti species complex (FIESC) are increasingly associated with plant disease, and human and animal health problems. Recently, an outbreak of kikuyu poisoning of cattle was attributed to the F. incarnatum-equiseti species complex. Thus, it is of importance to identify the natural distribution of members of the FIESC from the environment. The aim of this study was to use the phylogenetic signal within the TEF 1α gene region to characterise 54 F. incarnatum-equiseti isolates obtained from undisturbed soils from the grassland biome of South Africa. These isolates were further compared with members of the FIESC previously associated with kikuyu poisoning of cattle. The phylogenetic analysis indicated a high level of variation within this species complex. Several members were closely related to isolates implicated in the death of cattle from infected kikuyu grass.  相似文献   

2.
Species of Anoplodiscus Sonsino, 1890 were previously only known from host members of Sparidae. A new species, Anoplodiscus hutsonae n. sp. is proposed for museum specimens originally collected from species of Scolopsis Cuvier (Nemipteridae) off Heron Island and Lizard Island, Australia. Additionally, Anoplodiscus tai Ogawa, 1994 is synonymised with Anoplodiscus cirrusspiralis Roubal, Armitage & Rohde, 1983 due to a lack of support for differential characters, and Anoplodiscus richiardii is considered a species inquirenda. Anoplodiscus cirrusspiralis causes visible lesions on the skin and fins of its host, and may also contribute to poor food conversion rates in sparid aquaculture. Anoplodiscus cirrusspiralis has been recorded from cultured sparids in Australia, Japan, South Africa, and South Korea, and was implicated as a disease agent in fish from the former two countries. However, the discovery of A. cirrusspiralis on Chrysoblephus gibbiceps (Valenciennes), Ch. laticeps (Valenciennes) and Cymatoceps nasutus (Castelnau) in South Africa, ?Pagrus major (Temminck & Schlegel) in South Korea, and P. auratus (Forster) in Australia, New Zealand and Japan suggests that this species may have a wide distribution and low host-specificity within the Sparidae. In South Africa, A. cirrusspiralis was first encountered on a morbid C. nasutus and Ch. gibbiceps from two public aquaria in 2009 (Two Oceans Aquarium, Cape Town and uShaka Sea World, Durban, respectively). Additional material was collected from C. laticeps kept at an abalone farm in Hermanus that originated from Struisbaai on the South African south coast. Anoplodiscus cirrusspiralis is redescribed from the South African specimens. This is the first record of a member of Anoplodiscidae Tagliani, 1912 from Africa.  相似文献   

3.
Due to limited data available on the presence of antibiotic-resistant (ABR) bacteria in faeces of wild herbivores in South Africa, this study analysed resistance patterns for Escherichia coli isolates from wildebeest, zebra and giraffe in addition to pet and farm pig faeces. Total and faecal coliforms and E. coli were quantified in faecal matter using a most probable number (MPN) guideline procedure. Antibiotic resistance profiles against 12 selected antibiotics representing seven classes were determined for 30 randomly selected E. coli isolates from each animal using the European Committee on Antimicrobial Susceptibility Testing (EUCAST) disk diffusion procedure. While log10 MPN values per gram of animal faeces for total/faecal coliforms ranged from 4.51/4.11 to 5.70/5.50, the E. coli MPN values were in a range of 3.43–5.14. The proportion of ABR E. coli isolates ranged from 43% (giraffe) to 93% (zebra). About 47% of E. coli isolates from zebra faeces were categorized as multidrug-resistant (MDR), while for wildebeest and giraffe, no MDR isolates were detected. In comparison, 10% of E. coli isolates from pet pig and about 7% from farm pig faeces were categorized as MDR. Although most MDR isolates were resistant to at least one β-lactam antibiotic, only one MDR isolate from farm pig faeces was resistant to both norfloxacin and ciprofloxacin, the two fluoroquinolones tested. However, no resistance was detected to the tested carbapenems and tigecycline. The results of this study indicate that indigenous South African herbivores may serve as potential reservoirs and vectors for the dissemination of ABR E. coli strains.  相似文献   

4.
Tricholoma matsutake is an ectomycorrhizal fungus usually associated with Pinus densiflora in South Korea. Fruiting bodies (mushrooms) of T. matsutake are economically important due to their attractive aroma; yet, T. matsutake is uncultivatable and its habitat is rapidly being eradicated due to global climate change. Root-associated bacteria can influence the growth of ectomycorrhizal fungi that co-exist in the host rhizosphere and distinctive bacterial communities are associated with T. matsutake. In this study, we investigated how these bacterial communities affect T. matsutake growth by isolating bacteria from the roots of P. densiflora colonized by ectomycorrhizae of T. matsutake and co-culturing rootassociated bacteria with T. matsutake isolates. Thirteen species of bacteria (27 isolates) were found in pine roots, all belonging to the orders Bacillales or Burkholderiales. Two species in the genus Paenibacillus promoted the growth of T. matsutake in glucose poor conditions, likely using soluble metabolites. In contrast, other bacteria suppressed the growth of T. matsutake using both soluble and volatile metabolites. Antifungal activity was more frequent in glucose poor conditions. In general, pine rhizospheres harbored many bacteria that had a negative impact on T. matsutake growth and the few Paenibacillus species that promoted T. matsutake growth. Paenibacillus species, therefore, may represent a promising resource toward successful cultivation of T. matsutake.  相似文献   

5.
Secondary metabolites of 22 fungal strains (genus Aspergillus, section Usti) isolated at diverse geographic regions, including the Arctic permafrost deposits, were studied. The studied strains were found to synthesize a variety of biologically active compounds, structurally identified as drimane sesqueterpenoids, isoquinoline alkaloids (TMC-120 A?C, derivative 1), meroterpenoids (austalides О and J), and anthraquinone pigments (averufin, versicolorin C). Desferritriacetylfusigen production by A. calidoustus isolates is reported for the first time. The individual spectra of secondary metabolites were used for reidentification of 17 strains, of which 15 were identified as A. calidoustus and two, as A. pseudodeflectus.  相似文献   

6.
Species of Alternaria are serious plant pathogens, causing major losses on a wide range of crops. Leaf blight symptoms were observed on tomato leaves, and samples were collected from various regions. Isolation was done from symptomatic tomato leaves, and 15 representatives were selected from a collection of 65 isolates of Alternaria species. The virulence of Alternaria isolates was investigated on detached leaves (DL) and whole plants of tomato cv. Super strain B. A phylogenetic analysis was performed based on three partial gene regions, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the RNA polymerase second largest subunit (RPB2) and the Alternaria major allergen gene (Alt a 1). The potentiality of Alternaria isolates to produce toxins was also investigated on the basis of thin-layer chromatography (TLC). Our investigations revealed that Alternaria isolates showed different levels of virulence either on tomato plants or DL. Based on the phylogeny of three genes, Alternaria isolates encompassed two species of small-spored morphospecies: A. alternata (14 isolates) and A. arborescens (single isolate). The produced toxins varied among Alternaria isolates with tenuazonic acid (TeA) being the most abundant mycotoxin produced by most isolates. This study highlighted on other Alternaria species in Egypt that might represent a serious concern for tomato producers as causal agents of leaf blight over other species, i.e. A. solani.  相似文献   

7.
Three new species of the genus Menimus are described from Yunnan Province, China. Over 70 species of Menimus are distributed in the tropical and subtropical zones from India to Oceania and New Zealand. A new subgenus, Sinomenimus subgen. n., is erected with the type species M. kabaki sp. n. characterized by the absence of eyes and by the presence of the spermatheca and sharp depression at the posterior margin of the thoracic metasternite. The following new synonymy is established: Menimus Sharp, 1876 = Neomenimus Kaszab, 1939, syn. n., with the following new combinations resulting: Menimus clavatus (Kaszab, 1939) = Neomenimus clavatus Kaszab, 1939, comb, n.; Menimus biroi (Kaszab, 1939) = Neomenimus biroi Kaszab, 1939, comb, n.; Menimus setosus (Kaszab, 1939) = Neomenimus setosus Kaszab, 1939, comb, n.; Menimus brevissimus (Kaszab, 1939) = Neomenimus brevissimus Kaszab, 1939, comb. n.  相似文献   

8.
A review of the Oriental genus Cochinchinula Volk. (Coleoptera, Buprestidae, Polycestinae, Acmaeoderini) comprising three species is presented. The new species C. thailandica and C. bilyi spp. n. and the new genus Thaichinula gen. n. (type species T. ohmomoi sp. n.) from Thailand are described. A key to species of the genera Cochinchinula and Thaichinula is provided. The Nearctic genus Paracmaeoderoides Bellamy and Westcott is transferred from the subtribe Nothomorphina to the subtribe Acmaeoderoidina, and the South African genus Richtersveldia Bellamy is transferred from the subtribe Nothomorphina of Acmaeoderini to the tribe Ptosimini. The generic status is restored for another South African genus, Brachmaeodera Volkovitsh and Bellamy. The main evolutionary trends are discussed, and the taxonomic composition and classification of the tribe Acmaeoderini are clarified.  相似文献   

9.
A new species, Eurytoma koreana Zerova et Fursov, sp. n., is described from South Korea. The new species is closely related to Eurytoma verticillata (Fabricius) but differs in the structure of the antennae and the fore wings in both sexes. The holotype and paratypes are deposited in the collection of the Institute of Zoology, National Academy of Sciences ofUkraine, Kyiv, Ukraine.  相似文献   

10.
An improved TLC method ofFusaria metabolites detection and quantitation has been elaborated. A total 92 isolates of Discolor sectionFusaria from cereals and potato have been examined from the point of view of cultures morphology and ability to produce characteristic mycotoxins. Low nutrient media (CLA, SNA) were found as suitable for production of uniform and typical macroconidia in studied cultures. All 26 isolates ofF. sambucinum Fuckel (=F.sulphureum, Schlecht) formed diacetoxyscirpenol in amount 20-1000 mg/kg and all 17.F. crookwellense Burgess N. & T. produced zearalenone (16-602 mg/kg).F. graminearum Schwabe produced: zearalenone 14/14 isolates, deoxynivalenol 11/14 isolates, both up to 77 mg/kg. Out of 26F. culmorum cultures originating from Poland 22 produced zearalenone up to 675 mg/kg, 17/26 3 acetyldeoxynivalenol up to 280 mg/kg and 16/26 deoxynivalenol up to 220 mg/kg. The difference in metabolism agrees with the difference in morphology of those species.  相似文献   

11.
Thirty-nine human isolates of Campylobacter jejuni obtained from a national university hospital during 2007–2010 and 38 chicken isolates of C. jejuni were collected from poultry farms during 2009–2010 in South Korea were used in this study. Campylobacter genomic species and virulence-associated genes were identified by PCR. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed to compare their genetic relationships. All isolates were highly resistant to ciprofloxacin, nalidixic acid, and tetracycline. Of all isolates tested, over 94% contained seven virulence associated genes (flaA, cadF, racR, dnaJ, cdtA, cdtB, and cdtC). All isolates were classified into 39 types by PFGE clustering with 90% similarity. Some chicken isolates were incorporated into some PFGE types of human isolates. MLST analysis for the 39 human isolates and 38 chicken isolates resulted in 14 and 23 sequence types (STs), respectively, of which 10 STs were new. STs overlapped in both chicken and human isolates included ST-21, ST-48, ST-50, ST-51, and ST-354, of which ST-21 was the predominant ST in both human and chicken isolates. Through combined analysis of PFGE types and STs, three chicken isolates were clonally related to the three human isolates associated with food poisoning (VII-ST-48, XXII-ST-354, and XXVIII-ST-51). They were derived from geographically same or distinct districts. Remarkably, clonal spread of food poisoning pathogens between animals and humans was confirmed by population genetic analysis. Consequently, contamination of campylobacters with quinolone resistance and potential virulence genes in poultry production and consumption may increase the risk of infections in humans.  相似文献   

12.
Aflatoxins are toxic and carcinogenic secondary metabolites produced primarily by the filamentous fungi Aspergillus flavus and Aspergillus parasiticus and cause toxin contamination in food chain worldwide. Aspergillus oryzae and Aspergillus sojae are highly valued as koji molds in the traditional preparation of fermented foods, such as miso, sake, and shoyu. Koji mold species are generally perceived of as being nontoxigenic and are generally recognized as safe (GRAS). Fungal isolates were collected from a California orchard and a few were initially identified to be A. sojae using β-tubulin gene sequences blasted against NCBI data base. These new isolates all produced aflatoxins B1, B2, G1, and G2 and were named as Pistachio Winter Experiment (PWE) strains. Thus, it is very important to further characterize these strains for food safety purposes. The full length of aflR gene of these new isolates was sequenced. Comparison of aflR DNA sequences of PWE, A. parasiticus and A. sojae, showed that the aflatoxigenic PWE strains had the six base insertion (CTCATG) similar to domesticated A. sojae, but a pre-termination codon TGA at nucleotide positions 1153–1155 was absent due to a nucleotide codon change from T to C. Colony morphology and scanning microscopic imaging of spore surfaces showed similarity of PWE strains to both A. parasiticus and A. sojae. Concordance analysis of multi locus DNA sequences indicated that PWE strains were closely linked between A. parasiticus and A. sojae. The finding documented the first report that such unique strains have been found in North America and in the world.  相似文献   

13.
During the first half of the twentieth century, two accidental cases of introduction of Pissodes weevils were recorded from the southern hemisphere. The weevils in South Africa were identified as the deodar weevil (Pissodes nemorensis) and those in South America as the small banded pine weevil (Pissodes castaneus). Wide distribution of the two species in their invasive range, general difficulty in identifying some Pissodes spp., and the varying feeding and breeding behaviours of the species in South Africa has necessitated better evidence of species identity and genetic diversity of both species and population structure of the species in South Africa. Barcoding and the Jerry-to-Pat region of the COI gene were investigated. Morphometric data of the South African species was analysed. Our results confirmed the introduction of only one Pissodes species of North American origin to South Africa. However, this species is not P. nemorensis, but an unrecognized species of the P. strobi complex or a hybrid between P. strobi and P. nemorensis. Only P. castaneus, of European origin, was identified from South America. We identified ten mitochondrial DNA haplotypes from South Africa with evidence of moderate genetic structure among geographic populations. Terminal leader and bole-feeding weevils did not differ at the COI locus. A single haplotype was identified from populations of P. castaneus in South America. Results of the present study will have implications on quarantine, research and management of these insect species.  相似文献   

14.
Most species of Tamarix originate in Eurasia and at least five species have become invasive around the world, including South Africa. However, T. usneoides is indigenous to southern Africa, where the potential for biological control of the invasive species is being investigated. Recent research on the invasive species is reviewed here with particular reference to these South African biocontrol efforts. The successful biological control programme against invasive Tamarix in the USA, using several species of “Tamarisk beetle”, is being used as a guide for the South African research. The South African programme is complicated by firstly, the presence of the indigenous T. usneoides which raises the precision of host-specificity required, and secondly, the introduced and indigenous Tamarix have a high intrinsic value for phytoremediation of mine tailings dams in South Africa. The phylogenetic proximity of these Tamarix species to each other has contributed to this challenge, which has nevertheless been successfully addressed by molecular techniques used to separate the species. In addition, classical morphological techniques have been used to separate the Tamarisk beetles, so that now they can generally be matched to Tamarix tree species. Overall, it is concluded that given the broad knowledge now available on the ecology and identity of both the trees and their biocontrol agents, the prospects for successful biological control of Tamarix in South Africa are good.  相似文献   

15.

Background

Klebsiella variicola was very recently described as a new bacterial species and is very closely related to Klebsiella pneumoniae; in fact, K. variicola isolates were first identified as K. pneumoniae. Therefore, it might be the case that some isolates, which were initially classified as K. pneumoniae, are actually K. variicola. The aim of this study was to devise a multiplex-PCR probe that can differentiate isolates from these sister species.

Result

This work describes the development of a multiplex-PCR method to identify K. variicola. This development was based on sequencing a K. variicola clinical isolate (801) and comparing it to other K. variicola and K. pneumoniae genomes. The phylogenetic analysis showed that K. variicola isolates form a monophyletic group that is well differentiated from K. pneumoniae. Notably, the isolate K. pneumoniae 342 and K. pneumoniae KP5-1 might have been misclassified because in our analysis, both clustered with K. variicola isolates rather than with K. pneumoniae. The multiplex-PCR (M-PCR-1 to 3) probe system could identify K. variicola with high accuracy using the shared unique genes of K. variicola and K. pneumoniae genomes, respectively. M-PCR-1 was used to assay a collection of multidrug-resistant (503) and antimicrobial-sensitive (557) K. pneumoniae clinical isolates. We found K. variicola with a prevalence of 2.1% (23/1,060), of them a 56.5% (13/23) of the isolates were multidrug resistant, and 43.5% (10/23) of the isolates were antimicrobial sensitive. The phylogenetic analysis of rpoB of K. variicola-positive isolates identified by multiplex-PCR support the correct identification and differentiation of K. variicola from K. pneumoniae clinical isolates.

Conclusions

This multiplex-PCR provides the means to reliably identify and genotype K. variicola. This tool could be very helpful for clinical, epidemiological, and population genetics studies of this species. A low but significant prevalence of K. variicola isolates was found, implying that misclassification had occurred previously. We believe that our multiplex-PCR assay could be of paramount importance to understand the population dynamics of K. variicola in both clinical and environmental settings.
  相似文献   

16.
A collection of Puccinia triticina isolates was characterized for polymorphism of microsatellite loci and estimated for their differentiation by geographic origin. The collection included 20 isolates from the Ural region, 31 from West Siberia, 53 from Central Europe, 32 from the Northwest region, 32 from the Volga region, and 40 from the North Caucasus (24 from Dagestan and 16 from Krasnodar and Stavropol). The studied isolates were represented by 65 virulence phenotypes. In the polymorphism analysis of 18 microsatellite loci, 69 genotypes were determined. The index values of genetic distances (F st, R st, KB c) between populations for microsatellite loci indicated differentiation of P. triticina isolates according to geographical origin, and they were clustered into three groups: (1) Asian, (2) European, and (3) North Caucasian. The North Caucasian isolates from Krasnodar and Stavropol regions were closer in similarity to European isolates than the Dagestan ones. Current analysis confirmed the assumption made earlier on the basis of the virulence analysis about the existence of several geographic fungi populations in Russia.  相似文献   

17.
18.
Streptococcus dysgalactiae subsp. equisimilis (SDSE), belonging to the group C and G streptococci, are human pathogens reported to cause clinical manifestations similar to infections caused by Streptococcus pyogenes. To scrutinize the distribution of gene coding for S. pyogenes virulence factors in SDSE, 255 isolates were collected from humans infected with SDSE in Vellore, a region in southern India, with high incidence of SDSE infections. Initial evaluation indicated SDSE isolates comprising of 82.35% group G and 17.64% group C. A multiplex PCR system was used to detect 21 gene encoding virulence-associated factors of S. pyogenes, like superantigens, DNases, proteinases, and other immune modulatory toxins. As validated by DNA sequencing of the PCR products, sequences homologous to speC, speG, speH, speI, speL, ssa and smeZ of the family of superantigen coding genes and for DNases like sdaD and sdc were detected in the SDSE collection. Furthermore, there was high abundance (48.12% in group G and 86.6% in group C SDSE) of scpA, the gene coding for C5a peptidase in these isolates. Higher abundance of S. pyogenes virulence factor genes was observed in SDSE of Lancefield group C as compared to group G, even though the incidence rates in former were lower. This study not only substantiates detection of S. pyogenes virulence factor genes in whole genome sequenced SDSE but also makes significant contribution towards the understanding of SDSE and its increasing virulence potential.  相似文献   

19.
The component composition and content of mycotoxins in perennial grasses of five species of the genus Trifolium, selected from natural biocenoses in different periods of vegetation, were studied. In the terrestrial parts of plants, the permanent presence of alternariol, cyclopiazonic acid, and emodin was shown. It was noted that differences in contamination are most clearly expressed in meadow clover Trifolium pratense L. and white clover Trifolium repens L., while alsike clover Trifolium hybridum L. occupies an intermediate position. It was found that zigzag clover Trifolium medium L. and mountain clover Trifolium montanum L., morphologically close to meadow clover, practically did not differ in the composition of toxic metabolites. The ways of formation of metabolic equilibrium in plants with participation of microscopic fungi are discussed.  相似文献   

20.
Cheilanthoid ferns (Cheilanthoideae sensu PPG 1 2016) constitute an important group within the Pteridaceae and are cosmopolitan in distribution. In South America, there are 155 species distributed in 13 genera, among which the largest are Adiantopsis (35), Cheilanthes (27), and Doryopteris (22). Most of the cheilanthoid species are morphologically adapted to grow in arid to semi-arid conditions and show convergent evolution, which has implied difficulties in defining the genera throughout their taxonomic history (Copeland 1947, Tryon & Tryon 1973, Gastony & Rollo 1995, 1998, Kirkpatrick Systematic Botany, 32: 504–518, 2007, Rothfels et al. Taxon, 57: 712–724, 2008). Here, we sequenced two plastid markers (rbcL?+?trnL-F) of 33 South American cheilanthoid species, most of which have not been included in phylogenetic analyses previously. The South American species were analyzed together with South African and Australasian Cheilanthes and representatives of related cheilanthoid genera. The phylogenetic analysis showed that most Cheilanthes species are related to the genus Hemionitis, constituting different groups according to their distribution; moreover, three species—C. hassleri, C. pantanalensis, and C. obducta—appear as the sister clade of Hemionitis. Cheilanthes micropteris, the type species, is strongly supported in a clade with Australasian Cheilanthes plus five South American Cheilanthes species, all of which show a reduction in the number of spores per sporangium; this feature would be a synapomorphy for core Cheilanthes s.s. We found no support uniting other South American Cheilanthes to either the group of South African Cheilanthes or to core Cheilanthes s.s. On the other hand, C. geraniifolia, C. goyazensis, and C. bradei formed a clade related to Doryopteris that, with further study, could be considered as a new genus. The phylogenetic hypotheses presented here contribute substantially to the delimitation of Cheilanthes s.s. and related groups and provide the basis for re-examining the generic taxonomy.  相似文献   

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