958 resultados para 16S RDNA


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A new species of the genus Gluconacetobacter, for which the name Gluconacetobacter sacchari sp. nov. is proposed, was isolated from the leaf sheath of sugar cane and from the pink sugar-cane mealy bug, Saccharicoccus sacchari, found on sugar cane growing in Queensland and northern New South Wales, Australia, The nearest phylogenetic relatives in the alpha-subclass of the Proteobacteria are Gluconacetobacter liquefaciens and Gluconacetobacter diazotrophicus, which have 98.8-99.3% and 97.9-98.5% 16S rDNA sequence similarity, respectively, to members of Gluconacetobacter sacchari. On the basis of the phylogenetic positioning of the strains, DNA reassociation studies, phenotypic tests and the presence of the Q10 ubiquinone, this new species was assigned to the genus Gluconacetobacter. No single phenotypic characteristic is unique to the species, but the species can be differentiated phenotypically from closely related members of the acetic acid bacteria by growth in the presence of 0.01% malachite green, growth on 30% glucose, an inability to fix nitrogen and an inability to grow with the L-amino acids asparagine, glycine, glutamine, threonine and tryptophan when D-mannitol was supplied as the sole carbon and energy source. The type strain of this species is strain SRI 1794(T) (= DSM 12717(T)).

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A previously unknown chemolithoautotrophic arsenite-oxidizing bacterium has been isolated from a gold mine in the Northern Territory of Australia. The organism, designated NT-26, was found to be a gram-negative motile rod with two subterminal flagella. In a minimal medium containing only arsenite as the electron donor (5 mM), oxygen as the electron acceptor, and carbon dioxide-bicarbonate as the carbon source, the doubling time for chemolithoautotrophic growth was 7.6 h. Arsenite oxidation was found to be catalyzed by a periplasmic arsenite oxidase (optimum pH, 5.5). Based upon 16S rDNA phylogenetic sequence analysis, NT-26 belongs to the Agrobacterium/Rhizbium branch of the alpha-Proteobacteria and may represent a new species. This recently discovered organism is the most rapidly growing chemolithoautotrophic arsenite oxidizer known.

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There has been much progress in our understanding of the phylogeny and evolution of ticks, particularly hard ticks, in the past 5 years. Indeed, a consensus about the phylogeny of the hard ticks has emerged. Our current working hypothesis for the phylogeny of ticks is quite different to the working hypothesis of 5 years ago. So that the classification reflects our knowledge of ticks, several changes to the nomenclature of ticks are imminent. One subfamily, the Hyalomminae, will probably be sunk, yet another, the Bothriocrotoninae n. subfamily, will be created. Bothriocrotoninae n. subfamily, and Bothriocroton n. genus, are being created to house an early-diverging ('basal') lineage of endemic Australian ticks that used to be in the genus Aponomma (ticks of reptiles). There has been progress in our understanding of the subfamily Rhipicephalinae. The genus Rhipicephalus is almost certainly paraphyletic with respect to the genus Boophilus. Thus, the genus Boophilus will probably become a subgenus of Rhipicephalus. This change to the nomenclature, unlike other options, will keep the name Boophilus in common usage. Rhipicephalus (Boophilus) microplus may still called B. microplus, and Rhipicephalus (Boophilus) annulatus may still be called B. annulatus, but the nomenclature will have been changed to reflect our knowledge of the phylogeny and evolution of these ticks. New insights into the historical zoogeography of ticks will also be presented.

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The genus Macrobrachium Bate, 1868 is one of the best examples of widespread crustacean genera distributed globally throughout tropical and subtropical waters. Previous investigators have noted the systematic complexity of the group, and have suggested rearrangements within the family Palaemonidae. Our phylogenetic analysis of new mitochondrial DNA sequences of 58 species of Macrobrachium distributed mainly in America support the hypothesis of monophyly of this genus, if Cryphiops Dana, 1852 is accepted as a generic synonym. We concluded that the independent evolution of different types of life cycle (abbreviated larval development-ALD and extended larval development-ELD) must have occurred more than once in the history of the group. Similarly, we also concluded that the current type species of the genus, Macrobrachium americanum Bate, 1868, should not be considered valid, as previously proposed. The synonymy of two members of the `olfersi` species complex (M. birai Lobao, Melo&Fernandes, 1986 and M. holthuisi Genofre&Lobao, 1978) with M. olfersi (Wiegmann, 1836) was confirmed. Similar results were found in comparing M. petronioi Melo, Lobao&Fernandes, 1986 and M. potiuna (Muller, 1880), in which the genetic divergence placed M. petronioi within the level of intraspecific variation of M. potiuna. The taxonomic status of the genus Cryphiops, as well as theories on the origin of Macrobrachium, is also called into question.

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Bacteria phenotypically resembling members of the phylogenetically distinct planctomycete group of the domain Bacteria were isolated from postlarvae of the giant tiger prawn, Penaeus monodon. A selective medium designed in the light of planctomycete antibiotic resistance characteristics was used for this isolation. Planctomycetes were isolated from both healthy and monodon baculovirus-infected prawn postlarvae, The predominant colony type recovered from postlarvae regardless of viral infection status was nonpigmented. Other, less commonly observed types were pink or orange pigmented, A planctomycete-specific 16S rRNA-directed probe was designed and used to screen the isolates for their identity as planctomycetes prior to molecular phylogenetic characterization. 16S rRNA genes from nine prawn isolates together with two planctomycete reference strains (Planctomyces brasiliensis and Gemmata obscuriglobus) were sequenced and compared with reference sequences from the planctomycetes and other members of the domain Bacteria, Phylogenetic analyses and sequence signatures of the 16S rRNA genes demonstrated that the prawn isolates were members of the planctomycete group, Five representatives of the predominant nonpigmented colony type were members of the Pirellula group within the planctomycetes, as were three pink-pigmented colony type representatives. Homology values and tree topology indicated that representatives of the nonpigmented and pink-pigmented colony types formed two discrete clusters within the Pirellula group, not identical to any known Pirellula species, A sole representative of the orange colony type was a member of the Planctomyces group, virtually identical in 16S rDNA sequence to P. brasiliensis, and exhibited distinctive morphology.

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Analysis of the 16S rDNA sequence of Conglomeromonas largomobilis subsp. largomobilis supports a phylogenetic relationship with the species of the genus Azospirillum. This confirms results of previous nucleic acid hybridization studies (FALK, E. C., J. L. JOHNSON, V. D. L. BALDANI, J. DOBEREINER, and N. R. KRIEG. 1986. Int. J. Syst. Bacteriol. 36: 80-85). Conglomeromonas largomobilis subsp. largomobilis was most closely related to the species Azospirillim lipoferum and Azospirillum brasilense but sufficiently distant to warrant separate species status. Conglomeromonas largomobilis subsp. parooensis was more distantly related to the existing species of Azospirillum and represents an isolated subline of descent. On the basis of the phylogenetic evidence a prosposal is made to transfer the subspecies Conglom-eromonas largomobilis subsp. largomobilis to the genus Azospirillum as Azospirillum largomobile comb. nov. and to retain the genus Conglomeromonas by elevating the subspecies C. largomobilis subsp. parooensis to the type species of Conglomeromonas as Conglomeromonas parooensis sp. nov.

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Introduction: Denture stomatitis is a common lesion that affects denture wearers. Its multifactorial etiology seems to depend on a complex and poorly characterized biofilm. The purpose of this study was to assess the composition of the microbial biofilm obtained from complete denture wearers with and without denture stomatitis using culture-independent methods. Methods: Samples were collected from healthy denture wearers and from patients with denture stomatitis. Libraries comprising about 600 cloned 16S ribosomal DNA (rDNA) bacterial sequences and 192 cloned eukaryotic internal transcribed spacer (ITS) region sequences, obtained by polymerase chain reactions, were analyzed. Results: The partial 16S rDNA sequences revealed a total of 82 bacterial species identified in healthy subjects and patients with denture stomatitis. Twenty-seven bacterial species were detected in both biofilms, 29 species were exclusively present in patients with denture stomatitis, and 26 were found only in healthy subjects. Analysis of the ITS region revealed the presence of Candida sp. in both biofilms. Conclusion: The results revealed the extent of the microbial flora, suggesting the existence of distinct biofilms in healthy subjects and in patients with denture stomatitis.

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Due to a suspected human case of Brazilian Lyme-like disease in the city of Goiatins, Tocantins State, an epidemiological survey was carried out in eight counties in this region during September 2007 and February 2008, where 1,890 ticks were collected from domestic animals and from the environment. A total of eight tick species were identified: Rhipicephalus sanguineus, Rhipicephalus (Boophilus) microplus, Dermacentor nitens, Amblyomma cajennense, Amblyomma oblongoguttatum, Amblyomma ovale, Amblyomma parvum and Amblyomma tigrinum. The last four species were described for the first time in this region. Although human parasitism by ticks is frequently described in Goiatins, no ticks collected from humans were analyzed. The Study of ixodids in this region contributes with the survey of Brazilian ticks, as well as the elucidation of the possible transmission of the agent that caused the Brazilian Lyme-like disease case in Goiatins.

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Carios mimon is an argasid tick common on Chiroptera, originally described from larvae collected on bats Mimon crenulatum from Bolivia and Eptesicus brasiliensis from Uruguay. Later it was also registered from Argentina and recently included among the Brazilian tick fauna. In Brazil, this species is very aggressive to man, resulting in intense inflammatory response and pain. It is known only by the larval description and its morphology resembles that from other species currently included into the genus Carios, formerly classified into the subgenus Alectorobius, genus Ornithodoros. Here we describe adults and redescribe the larva of C. mimon, based on light and scanning electron microscopy. Remarks about its morphological similarity with other species of this genus are also discussed. Molecular analysis inferred from a portion of the 16S rRNA mitochondrial gene placed C. mimon in a cluster supported by maximal bootstrap value (100%) with other argasid species (mostly bat parasites in the New World), which have been classified into either the genus Ornithodoros or Carios, depending on the Argasidae classification adopted by different authors.

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Phylogenetic analyses based on mitochondrial 16S rDNA sequences were generated from Rhipicephalus sanguineus group specimens collected in 29 localities among 9 Latin-American countries, plus ticks collected in South Africa, Spain, and Italy. Sequences from Latin America generated six different haplotypes (A, B, C, D, E, and F). Phylogenetic analyses generated trees that segregated our tick sequences into two distinct clades: one is represented by haplotypes A-C, and South African R. sanguineus and Rhipicephalus turanicus ticks; the second clade is represented by haplotypes D-F, and European R. sanguineus and R. turanicus ticks. When haplotypes A-Fare plotted in the Latin America map according to their geographical coordinates, it is clearly seen that haplotypes D-F are restricted to the southern portion of this continent, whereas haplotypes A-C are distributed in areas between northern Mexico and Brazil (except for the extreme south of this last country, where haplotype E was present). Hence, our phylogenetic analyses separated New World specimens of R. sanguineus into two distinct clades, one represented by tropical and subtropical populations (haplotypes A-C), here designated as the `tropical` species. On the other hand, haplotypes D-F are here designated as the `temperate` species because of their distribution in the southern portion of South America. Until recently, it was assumed that the R. sanguineus group was represented by a single species in the New World, namely R. sanguineus. While the present results coupled with recent studies support the presence of at least two species under the taxon R. sanguineus in the New World, they also show that even in the Old World, the taxon R. sanguineus might be represented by more than one species, since our phylogenetic analysis segregated European and South African R. sanguineus ticks into two distinct clades. The same can be applied for Spanish and South African R. turanicus. (C) 2010 Elsevier B.V. All rights reserved.

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Males, females, and larvae of Carios fonsecai sp. nov. are described from free-living ticks collected in a cave at Bonito, state of Mato Grosso do Sul, Brazil. The presence of cheeks and legs with micromammillate cuticle makes adults of C. fonsecai morphologically related to a group of argasid species (mostly bat-associated) formerly classified into the subgenus Alectorobius, genus Ornithodoros. Examination of larvae indicates that C. fonsecai is clearly distinct from most of the previously described Carios species formerly classified into the subgenus Alectorobius, based primarily on its larger body size, dorsal setae number, dorsal plate shape, and hypostomal morphology. On the other hand, the larva of C. fonsecai is most similar to Carios peropteryx, and Carios peruvianus, from which differences in dorsal plate length and width, tarsal setae, and hypostome characteristics are useful for morphological differentiation. The mitochondrial 16S rDNA sequence of C. fonsecai showed to be closest (85-88% identity) to several corresponding sequences of different Carios species available in GenBank. Bats identified as Peropteryx macrotis and Desmodus rotundus were found infested by C. fonsecai larvae in the same cave where the type series was collected. C. fonsecai showed to be aggressive to humans in the laboratory.

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The tick Amblyomma parkeri Fonseca and Arago was described in 1952, based on female and immature ticks collected in the states of So Paulo and Santa Catarina, Brazil. Thereafter, there has been no further report of A. parkeri, and the male has remained unknown. Herein, we examined ticks collected on porcupines from a locality in the state of So Paulo. Some of the ticks were identified as Amblyomma longirostre (Koch, 1844), whereas others as A. parkeri, including male specimens, for which we provide the first description. We also provide additional reports of A. parkeri after examining collections of A. longirostre and Amblyomma geayi Neumann, 1899 from different tick collections. Morphological evidence to support the original description of A. parkeri is presented, supported by molecular analyses of portions of the 16S rRNA and 12S rRNA mitochondrial genes. Morphological particularities to separate A. parkeri, A. longirostre, and A. geayi are provided.

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We inferred the phylogeny of 33 species of ticks from the subfamilies Rhipicephalinae and Hyalomminae from analyses of nuclear and mitochondrial DNA and morphology. We used nucleotide sequences from 12S rRNA, cytochrome c oxidase I, internal transcribed spacer 2 of the nuclear rRNA, and 18S rRNA. Nucleotide sequences and morphology were analyzed separately and together in a total-evidence analysis. Analyses of the five partitions together (3303 characters) gave the best-resolved and the best-supported hypothesis so far for the phylogeny of ticks in the Rhipicephalinae and Hyalomminae, despite the fact that some partitions did not have data for some taxa. However, most of the hidden conflict (lower support in the total-evidence analyses compared to that in the individual analyses) was found in those partitions that had taxa without data. The partitions with complete taxonomic sampling had more hidden support (higher support in the total-evidence analyses compared to that in the separate-partition analyses) than hidden conflict. Mapping of geographic origins of ticks onto our phylogeny indicates an African origin for the Rhipicephalinae sensu lato (i.e., including Hyalomma spp.), the Rhipicephalus-Boophilus lineage, the Dermacentor-Anocentor lineage, and the Rhipicephalus-Booophilus-Nosomma-Hyalomma-Rhipicentor lineage. The Nosomma-Hyalomma lineage appears to have evolved in Asia. Our total-evidence phylogeny indicates that (i) the genus Rhipicephalus is paraphyletic with respect to the genus Boophilus, (ii) the genus Dermacentor is paraphyletic with respect to the genus Anocentor, and (iii) some subgenera of the genera Hyalomma and Rhipicephalus are paraphyletic with respect to other subgenera in these genera. Study of the Rhipicephalinae and Hyalomminae over the last 7 years has shown that analyses of individual datasets (e.g., one gene or morphology) seldom resolve many phylogenetic relationships, but analyses of more than one dataset can generate well-resolved phylogenies for these ticks. (C) 2001 Academic Press.

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Aim-To analyse the microflora of subgingival plaque from patients with Papillon-Lefevre syndrome (PLS), which is a very rare disease characterised by palmar-plantar hyperkeratosis with precocious periodontal destruction. Methods-Bacterial isolates were identified using a combination of commercial identification kits, traditional laboratory tests, and gas liquid chromatography. Some isolates were also subjected to partial 16S rDNA sequencing. Plaque samples were also assayed for the presence of Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans in a quantitative enzyme linked immunosorbent assay (ELISA) using monoclonal antibodies. Results-The culture results showed that most isolates were capnophilic and facultatively anaerobic species-mainly Capnocytophaga spp and Streptococcus spp. The latter included S constellatus, S oralis, and S sanguis. Other facultative bacteria belonged to the genera gemella, kingella, leuconostoc, and stomatococcus. The aerobic bacteria isolated were species of neisseria and bacillus. Anaerobic species included Prevotella intermedia, P melaninogenica, and P nigrescens, as well as Peptostreptococcus spp. ELISA detected P gingivalis in one patient in all sites sampled, whereas A actinomycetemcomitans was detected in only one site from the other patient. Prevotella intermedia was present in low numbers. Conclusions-Patients with PLS have a very complex subgingival flora including recognised periodontal pathogens. However, no particular periodontopathogen is invariably associated with PLS.

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The option for biological nitrogen removal has recently been broadened with the description of simultaneous nitrification/denitrification, anaerobic ammonium oxidation (ANAMMOX) and the concept of CANON (completely autotrophic nitrogen removal over nitrite). An autotrophic anaerobic ammonium oxidation (AAAO) consortium was successfully selected and enriched from municipal treatment plant sludges in Sydney, Australia, but not from industrial coke-oven wastewater sludges. Chemolithoautotrophic basic salt (CLABS) medium was used in the selection of AAAO organisms and chloramphenicol was added to the initial stage of selection to eliminate denitrifiers. Two different temperatures, 37degreesC and 55degreesC, were used in the selection of mesophilic and thermophilic consortia, respectively. Thermophilic AAAO organisms were not selected at 55degreesC. Mesophilic AAAO activities, however, were evident in both batch and continuous cultures, whereby ammonium was consumed concurrently with a decrease of nitrite, giving a ratio of 1:1-1:1.3 in ammonium removal rate over nitrite consumption rate. A continuous-mode mesophilic fixed-bed reactor was established to enrich the AAAO consortium. After 1 year, biofilms, pinkish in color, had developed on the support media and side wall of the feed-line tubing. Ammonium and nitrite consumption increased from similar to15 mg to 60 mg d(-1) L-1 over a period of 243 days. Later, transmission electron microscopy (TEM) and fluorescence in situ hybridization (FISH) techniques revealed that the dominant cell type in the AAAO consortium had a similar morphology and 16S rDNA sequence homology to that of the recently described ANAMMOX organism, Brocadia anammoxidans.