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Johanna L. Baily Guillaume Méric Sion Bayliss Geoffrey Foster Simon E. Moss Eleanor Watson Ben Pascoe Jane Mikhail Romain Pizzi Robert J. Goldstone David G. E. Smith Kim Willoughby Ailsa J. Hall Mark P. Dagleish 《Molecular ecology》2015,24(1):208-221
Environmental pollution often accompanies the expansion and urbanization of human populations where sewage and wastewaters commonly have an impact on the marine environments. Here, we explored the potential for faecal bacterial pathogens, of anthropic origin, to spread to marine wildlife in coastal areas. The common zoonotic bacterium Campylobacter was isolated from grey seals (Halichoerus grypus), an important sentinel species for environmental pollution, and compared to isolates from wild birds, agricultural sources and clinical samples to characterize possible transmission routes. Campylobacter jejuni was present in half of all grey seal pups sampled (24/50 dead and 46/90 live pups) in the breeding colony on the Isle of May (Scotland), where it was frequently associated with histological evidence of disease. Returning yearling animals (19/19) were negative for C. jejuni suggesting clearance of infection while away from the localized colony infection source. The genomes of 90 isolates from seals were sequenced and characterized using a whole‐genome multilocus sequence typing (MLST) approach and compared to 192 published genomes from multiple sources using population genetic approaches and a probabilistic genetic attribution model to infer the source of infection from MLST data. The strong genotype‐host association has enabled the application of source attribution models in epidemiological studies of human campylobacteriosis, and here assignment analyses consistently grouped seal isolates with those from human clinical samples. These findings are consistent with either a common infection source or direct transmission of human campylobacter to grey seals, raising concerns about the spread of human pathogens to wildlife marine sentinel species in coastal areas. 相似文献
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Samuel K. Sheppard Lu Cheng Guillaume Méric Caroline P. A. de Haan Ann‐Katrin Llarena Pekka Marttinen Ana Vidal Anne Ridley Felicity Clifton‐Hadley Thomas R. Connor Norval J. C. Strachan Ken Forbes Frances M. Colles Keith A. Jolley Stephen D. Bentley Martin C. J. Maiden Marja‐Liisa Hänninen Julian Parkhill William P. Hanage Jukka Corander 《Molecular ecology》2014,23(10):2442-2451
Homologous recombination between bacterial strains is theoretically capable of preventing the separation of daughter clusters, and producing cohesive clouds of genotypes in sequence space. However, numerous barriers to recombination are known. Barriers may be essential such as adaptive incompatibility, or ecological, which is associated with the opportunities for recombination in the natural habitat. Campylobacter jejuni is a gut colonizer of numerous animal species and a major human enteric pathogen. We demonstrate that the two major generalist lineages of C. jejuni do not show evidence of recombination with each other in nature, despite having a high degree of host niche overlap and recombining extensively with specialist lineages. However, transformation experiments show that the generalist lineages readily recombine with one another in vitro. This suggests ecological rather than essential barriers to recombination, caused by a cryptic niche structure within the hosts. 相似文献
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Samuel K. Sheppard Xavier Didelot Keith A. Jolley Aaron E. Darling Ben Pascoe Guillaume Meric David J. Kelly Alison Cody Frances M. Colles Norval J. C. Strachan Iain D. Ogden Ken Forbes Nigel P. French Philip Carter William G. Miller Noel D. McCarthy Robert Owen Eva Litrup Michael Egholm Jason P. Affourtit Stephen D. Bentley Julian Parkhill Martin C. J. Maiden Daniel Falush 《Molecular ecology》2013,22(4):1051-1064
Hybridization between distantly related organisms can facilitate rapid adaptation to novel environments, but is potentially constrained by epistatic fitness interactions among cell components. The zoonotic pathogens Campylobacter coli and C. jejuni differ from each other by around 15% at the nucleotide level, corresponding to an average of nearly 40 amino acids per protein‐coding gene. Using whole genome sequencing, we show that a single C. coli lineage, which has successfully colonized an agricultural niche, has been progressively accumulating C. jejuni DNA. Members of this lineage belong to two groups, the ST‐828 and ST‐1150 clonal complexes. The ST‐1150 complex is less frequently isolated and has undergone a substantially greater amount of introgression leading to replacement of up to 23% of the C. coli core genome as well as import of novel DNA. By contrast, the more commonly isolated ST‐828 complex bacteria have 10–11% introgressed DNA, and C. jejuni and nonagricultural C. coli lineages each have <2%. Thus, the C. coli that colonize agriculture, and consequently cause most human disease, have hybrid origin, but this cross‐species exchange has so far not had a substantial impact on the gene pools of either C. jejuni or nonagricultural C. coli. These findings also indicate remarkable interchangeability of basic cellular machinery after a prolonged period of independent evolution. 相似文献
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Shantanu Kundu Vikas Kumar Kaomud Tyagi Rajasree Chakraborty Kailash Chandra 《Ecology and evolution》2019,9(18):10854-10868
The characterization of a complete mitogenome is widely used in genomics studies for systematics and evolutionary research. However, the sequences and structural motifs contained within the mitogenome of Testudines taxa have rarely been examined. The present study decodes the first complete mitochondrial genome of the Indian Tent Turtle, Pangshura tentoria (16,657 bp) by using next‐generation sequencing. This denovo assembly encodes 37 genes: 13 protein‐coding genes (PCGs), 22 transfer RNA (tRNAs), two ribosomal RNA, and one control region (CR). Most of the genes were encoded on majority strand, except for one PCG (NADH dehydrogenase subunit 6) and eight tRNAs. Most of the PCGs were started with an ATG initiation codon, except for Cytochrome oxidase subunit 1 with “GTG” and NADH dehydrogenase subunit 5 with “ATA.” The termination codons, “TAA” and “AGA” were observed in two subunits of NADH dehydrogenase gene. The relative synonymous codon usage analysis revealed the maximum abundance of alanine, isoleucine, leucine, and threonine. The nonsynonymous/synonymous ratios were <1 in all PCGs, which indicates strong negative selection among all Geoemydid species. The study also found the typical cloverleaf secondary structure in most of the tRNA genes, except for serine with the lack of the conventional DHU arm. The comparative study of Geoemydid mitogenomes revealed the occurrence of tandem repeats was frequent in the 3′ end of CR. Further, two copies of a unique tandem repeat “TTCTCTTT” were identified in P. tentoria. The Bayesian and maximum‐likelihood phylogenetic trees using concatenation of 13 PCGs revealed the close relationships of P. tentoria with Batagur trivittata in the studied dataset. All the Geoemydid species showed distinct clustering with high bootstrap support congruent with previous evolutionary hypotheses. We suggest that the generations of more mitogenomes of Geoemydid species are required, to improve our understanding of their in‐depth phylogenetic and evolutionary relationships. 相似文献
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The apostome family Colliniidae includes species that are adapted to the hemocoel/blood of various invertebrates, particularly crustaceans. To explore the phylogeny of these sanguicolous apostomes, Metacollinia luciensis was collected in August 2015 at Roscoff from the amphipod host, Orchestia gammarellus. Ciliates were Protargol stained and DNA was extracted. The small subunit rRNA (SSUrRNA) and cytochrome c oxidase subunit I (cox1) genes were amplified. Molecular phylogenetic analyses of the SSUrRNA genes unambiguously grouped M. luciensis with other apostomes with robust bootstrap support, but separated it distinctly from the pseudocolliniid clade. While there are only cox1 sequences for a subset of these apostomes, M. luciensis was also distant from the pseudocolliniids and separated from them by species of the exuviotrophic apostome Hyalophysa. These results confirm the distinctness of the families Colliniidae and Pseudocolliniidae. 相似文献
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An immunomagnetic separation/loop‐mediated isothermal amplification method for rapid direct detection of thermotolerant Campylobacter spp. during poultry production 
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下载免费PDF全文 M.R. Romero M. D'Agostino A. Pérez Arias S. Robles C. Fernández Casado L. Orueta Iturbe O. Gurrutxaga Lerma M. Andreou N. Cook 《Journal of applied microbiology》2016,120(2):469-477
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Campylobacter and Salmonella are prevalent in broiler farms in Kyushu,Japan: results of a 2‐year distribution and circulation dynamics audit 下载免费PDF全文
下载免费PDF全文 W. Yamazaki R. Uemura S. Sekiguchi J.‐B. Dong S. Watanabe Y. Kirino H. Mekata N. Nonaka J. Norimine M. Sueyoshi Y. Goto Y. Horii M. Kurogi S. Yoshino N. Misawa 《Journal of applied microbiology》2016,120(6):1711-1722
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Jing Wang Richard J. Abbott Pär K. Ingvarsson Jianquan Liu 《Ecology and evolution》2014,4(7):1019-1029
Because of introgressive hybridization, closely related species can be more similar to each other in areas of range overlap (parapatry or sympatry) than in areas where they are geographically isolated from each other (allopatry). Here, we report the reverse situation based on nuclear genetic divergence between two fir species, Abies chensiensis and Abies fargesii, in China, at sites where they are parapatric relative to where they are allopatric. We examined genetic divergence across 126 amplified fragment length polymorphism (AFLP) markers in a set of 172 individuals sampled from both allopatric and parapatric populations of the two species. Our analyses demonstrated that AFLP divergence was much greater between the species when comparisons were made between parapatric populations than between allopatric populations. We suggest that selection in parapatry may have largely contributed to this increased divergence. 相似文献
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Guilherme H. S. Freitas Anderson V. Chaves Lílian M. Costa Fabrício R. Santos Marcos Rodrigues 《Ibis》2012,154(4):738-755
We describe Cinclodes espinhacensis (Furnariidae), a new species discovered at high elevation in the southern portion of the Espinhaço Range, in the state of Minas Gerais, southeastern Brazil. This new taxon is closely related to the Long‐tailed Cinclodes Cinclodes pabsti, endemic to Serra Geral, southern Brazil. We present diagnostic morphological, genetic and vocal characters that support the rank of species for this allopatric taxon. It is readily distinguishable from C. pabsti by its much darker back, chest and flanks, lower body mass, shorter tarsus‐length, lower frequency of vocalizations, and longer duration of calls. DNA sequence data estimate that the divergence time between this new species and Cinclodes pabsti occurred c. 220 000 years ago, during the late Pleistocene. This discovery illustrates remarkable biogeographical connections among the cold regions of South America. The new species has a restricted range and we suggest it meets the criteria of the IUCN Red List category of Endangered. 相似文献