scholarly journals Genetic Analysis of Helicobacter pylori Strain Populations Colonizing the Stomach at Different Times Postinfection

2007 ◽  
Vol 189 (10) ◽  
pp. 3834-3845 ◽  
Author(s):  
Nina R. Salama ◽  
Gerardo Gonzalez-Valencia ◽  
Brooke Deatherage ◽  
Francisco Aviles-Jimenez ◽  
John C. Atherton ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Genetic Divergence ◽  
Random Amplified Polymorphic Dna ◽  
Genetic Exchange ◽  
Comparative Genomic ◽  
New Host ◽  
Genetic Changes ◽  
Individual Host ◽  
Single Host ◽  
The One

ABSTRACT Genetic diversity of the human gastric pathogen Helicobacter pylori in an individual host has been observed; whether this diversity represents diversification of a founding strain or a mixed infection with distinct strain populations is not clear. To examine this issue, we analyzed multiple single-colony isolates from two to four separate stomach biopsies of eight adult and four pediatric patients from a high-incidence Mexican population. Eleven of the 12 patients contained isolates with identical random amplified polymorphic DNA, amplified fragment length polymorphism, and vacA allele molecular footprints, whereas a single adult patient had two distinct profiles. Comparative genomic hybridization using whole-genome microarrays (array CGH) revealed variation in 24 to 67 genes in isolates from patients with similar molecular footprints. The one patient with distinct profiles contained two strain populations differing at 113 gene loci, including the cag pathogenicity island virulence genes. The two strain populations in this single host had different spatial distributions in the stomach and exhibited very limited genetic exchange. The total genetic divergence and pairwise genetic divergence between isolates from adults and isolates from children were not statistically different. We also analyzed isolates obtained 15 and 90 days after experimental infection of humans and found no evidence of genetic divergence, indicating that transmission to a new host does not induce rapid genetic changes in the bacterial population in the human stomach. Our data suggest that humans are infected with a population of closely related strains that vary at a small number of gene loci, that this population of strains may already be present when an infection is acquired, and that even during superinfection genetic exchange among distinct strains is rare.

scholarly journals Slow Genetic Divergence of Helicobacter pylori Strains during Long-Term Colonization

2005 ◽  
Vol 73 (8) ◽  
pp. 4818-4822 ◽  
Author(s):  
Annelie Lundin ◽  
Britta Björkholm ◽  
Ilya Kupershmidt ◽  
Magnus Unemo ◽  
Peter Nilsson ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Genetic Divergence ◽  
Bacterial Species ◽  
Pcr Amplification ◽  
Genetic Change ◽  
Genetic Changes ◽  
Single Strain ◽  
Divergent Gene ◽  
Asymptomatic Adult ◽  
H Pylori

ABSTRACT The genetic variability of Helicobacter pylori is known to be high compared to that of many other bacterial species. H. pylori is adapted to the human stomach, where it persists for decades, and adaptation to each host results in every individual harboring a distinctive bacterial population. Although clonal variants may exist within such a population, all isolates are generally genetically related and thus derived from a common ancestor. We sought to determine the rate of genetic change of H. pylori over 9 years in two asymptomatic adult patients. Arbitrary primed PCR confirmed the relatedness of individual subclones within a patient. Furthermore, sequencing of 10 loci (∼6,000 bp) in three subclones per time and patient revealed only two base pair changes among the subclones from patient I. All sequences were identical among the patient II subclones. However, PCR amplification of the highly divergent gene amiA revealed great variation in the size of the gene between the subclones within each patient. Thus, both patients harbored a single strain with clonal variants at both times. We also studied genetic changes in culture- and mouse-passaged strains, and under both conditions no genetic divergence was found. These results suggest that previous estimates of the rate of genetic change in H. pylori within an individual might be overestimates.

scholarly journals Helicobacter pylori cag pathogenicity island genotype diversity within the gastric niche of a single host

2007 ◽  
Vol 56 (5) ◽  
pp. 664-669 ◽  
Author(s):  
Mario José Matteo ◽  
Gabriela Granados ◽  
Cecilia Valeria Pérez ◽  
Martín Olmos ◽  
Cristian Sanchez ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Clinical Presentation ◽  
Random Amplified Polymorphic Dna ◽  
Positive Culture ◽  
Pathogenicity Island ◽  
Empty Site ◽  
Multiple Biopsies ◽  
Single Host ◽  
Dna Pcr ◽  
Positive Half

cag pathogenicity island (PAI) integrity was investigated in isolates from multiple biopsies recovered from 40 patients in an attempt to determine the co-existence of a varying cagPAI-positive to cagPAI-negative ratio in a single host. Six biopsies were obtained from each patient during the same endoscopic session. cagPAI analysis included amplification of seven loci (cagA, cagE, cagG, cagM, cagT, HP0527 and HP0524) and the left end of cagII (LEC). Absence of the island was confirmed by empty-site PCR. lspA-glmM RFLP and random amplified polymorphic DNA PCR were used for strain delineation. The number of biopsies with Helicobacter pylori-positive culture ranged from three to six per patient and a total of 218 isolates were recovered. Mixed infection was only found in two patients. Nearly one-third of the 40 patients harboured isolates with an intact cagPAI in all niches, another third of the isolates were empty-site-positive in all niches, whilst the remaining third of the isolates had a disrupted cagPAI in all or at least one of the niches. Co-existence of variants of the same strain with different cagPAI genotypes was observed in one-quarter of patients. The variations in cagPAI genotype included co-existence of: diverse cagPAI deletions in different niches, variants with intact and with partially deleted islands, variants with empty-site-positive and with partially deleted cagPAIs, and variants with an intact cagPAI and with empty-site-positive. Half of the patients with different cagPAI genotypes harboured an intact cagPAI in at least one niche. Co-existence of diverse genotypes of putative virulence factors in a single host must be considered when drawing a correlation with clinical presentation.

scholarly journals Pentastomids infecting an invader lizard, Hemidactylus mabouia (Gekkonidae) in northeastern Brazil

2008 ◽  
Vol 68 (3) ◽  
pp. 611-615 ◽  
Author(s):  
LA. Anjos ◽  
WO. Almeida ◽  
A. Vasconcellos ◽  
EMX. Freire ◽  
CFD. Rocha
Keyword(s):  
Feeding Habits ◽  
Infection Intensity ◽  
First Record ◽  
Host Population ◽  
Northeastern Brazil ◽  
Parasitism Rate ◽  
Intensity Of Infection ◽  
New Host ◽  
Single Host ◽  
Hemidactylus Mabouia

From January to April 2006, 37 specimens of Hemidactylus mabouia were collected in houses, in the municipality of Barbalha (7° 20' S and 39° 18' W), Ceará State, Northeast Brazil. Among the individuals captured, 17 were infected with pentastomids, totalling a prevalence of 45.9%, which did not differ between sexes. Host size did not influence the infection intensity. Two species of pentastomids were found: Raillietiella frenatus and R. mottae. The prevalence of R. frenatus (43.2%) was higher than R. mottae (2.7%), whereas the infection intensity of R. frenatus was comparatively lower (1.8 ± 1.4) than R. mottae (36 parasites in a single host). Overall mean intensity of infection was 3.8 ± 8.4 pentastomids. We found no pentastomid infecting juvenile geckos. The parameters of infection in this host population are in accordance to the findings of other studies, in which the high parasitism rate was associated to the feeding habits of geckos living in houses and buildings. Hemidactylus mabouia is a new host to R. mottae and the infection by R. frenatus is the first record of the occurrence this pentastomid species in Brazil.

Dilemmas in Prenatal Chromosomal Diagnosis Revealed Through a Single Center's 30 Years' Experience and 90,000 Cases

2015 ◽  
Vol 38 (3) ◽  
pp. 218-232 ◽  
Author(s):  
Christopher Konialis ◽  
Constantinos Pangalos ◽  
. InterGenetics
Keyword(s):  
Detection Rate ◽  
Chromosomal Abnormalities ◽  
Diagnostic Yield ◽  
Prenatal Testing ◽  
Minimal Invasive ◽  
Molecular Diagnostic ◽  
Comparative Genomic ◽  
High Detection Rate ◽  
Molecular Approaches ◽  
The One

Introduction: The aim of this article is to provide a perspective of prenatal chromosomal diagnosis (PCD) derived from a single center's evolving experience from ∼90,000 consecutive prenatal cases and to highlight important issues and current dilemmas. Materials and Methods: Prenatal cases in this study (1985-2013) were referred for various indications, and PCD was performed by standard karyotype in 84,255 cases, multiplex ligation-dependent probe amplification (MLPA) panel in 3,010 cases and standalone array comparative genomic hybridization (aCGH) in 3,122 cases. Results: Classic karyotype revealed 1.7 and 7.9% of pathological cases in amniotic fluid and CVS samples, respectively, with common aneuploidies accounting for 59.6 and 64.3% of the total abnormal. Molecular approaches increased the diagnostic yield by 0.6% for MLPA and 1.6% for aCGH, uncovering pathogenic chromosomal abnormalities undetectable by karyotype analysis. Conclusions: Current molecular diagnostic capabilities and the recent introduction of noninvasive prenatal testing (NIPT) point to one current major dilemma in PCD, with serious implications in genetic counseling, relating on the one hand to reaping the benefits from the high detection rate afforded through aCGH but accepting an invasive risk, and on the other hand, offering a lower detection rate practically only for Down syndrome, with minimal invasive risk.

Parasites of round goby, Neogobius melanostomus, currently invading the Elbe River

2019 ◽  
Vol 48 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Yuriy Kvach ◽  
Markéta Ondračková ◽  
Michal Janáč ◽  
Vadym Krasnovyd ◽  
Mária Seifertová ◽  
...  
Keyword(s):  
Round Goby ◽  
Parasite Community ◽  
Neogobius Melanostomus ◽  
Published Data ◽  
Tidal Zone ◽  
New Host ◽  
The North ◽  
Round Gobies ◽  
The Elbe River ◽  
The One

Abstract The round goby, Neogobius melanostomus, is a Ponto-Caspian fish species currently found in many parts of Europe, including the North Sea riverine deltas. The objective of this study was to examine the parasite community of fish caught in the lower Elbe (Süderelbe – tidal zone; Geesthacht – non-tidal) in Germany and compare it with published data from the upper Elbe (Ústí nad Labem) in the Czech Republic. Twelve parasite taxa were recorded in the lower Elbe, six in the Süderelbe and nine near the city of Geesthacht. Süderelbe fish were mainly infected with Angullicola crassus larvae, while gobies from Geesthacht – with glochidia and sporadically occurring Pomporhynchus laevis, and the opposite situation was observed at Ústí nad Labem. It appears that a large tidal weir at Geesthacht significantly contributes to the division of the round goby population, with the Geesthacht parasite community being more similar to that at Ústí nad Labem than the one from the Süderelbe, thus increasing the likelihood that shipping from Hamburg was the introduction vector to Ústí nad Labem. We also recorded Acanthocephalus rhinensis in the Elbe for the first time, and in a new host – the round goby. Thus, round gobies may represent a new vector for the introduction of this parasite along the Elbe.

scholarly journals Clonality Analysis ofHelicobacter pyloriin Patients Isolated from Several Biopsy Specimens and Gastric Juice in a Japanese Urban Population by Random Amplified Polymorphic DNA Fingerprinting

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Nariaki Toita ◽  
Shin-ichi Yokota ◽  
Nobuhiro Fujii ◽  
Mutsuko Konno
Keyword(s):  
Gastric Juice ◽  
Urban Population ◽  
Random Amplified Polymorphic Dna ◽  
Clonal Diversity ◽  
Japanese Patients ◽  
Upper Gastrointestinal Endoscopy ◽  
Rapd Fingerprinting ◽  
Biopsy Specimens ◽  
Single Host ◽  
H Pylori

Background. The number ofHelicobacter pyloriclones infecting a single host has been discussed in numerous reports. The number has been suggested to vary depending on the regions in the world.Aim. The purpose of this study was to examine the number of clones infecting a single host in a Japanese urban population.Materials and Methods. Thirty-one Japanese patients undergoing upper gastrointestinal endoscopy were enrolled in this study.H. pyloriisolates (total 104 strains) were obtained from biopsy specimens (antrum, corpus, and duodenum) and gastric juice. Clonal diversity was examined by the random amplified polymorphic DNA (RAPD) fingerprinting method.Results. The RAPD fingerprinting patterns of isolates from each patient were identical or very similar. And the isolates obtained from several patients with 5- to 9-year intervals showed identical or very similar RAPD patterns.Conclusion. Each Japanese individual of an urban population is predominantly infected with a singleH. pyloriclone.

scholarly journals Multiple in vivo passages enhance the ability of a clinical Helicobacter pylori isolate to colonize the stomach of Mongolian gerbils and to induce gastritis

2005 ◽  
Vol 39 (2) ◽  
pp. 221-229 ◽  
Author(s):  
A Bleich ◽  
I Köhn ◽  
S Glage ◽  
W Beil ◽  
S Wagner ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Bacterial Colonization ◽  
Underlying Mechanism ◽  
Mongolian Gerbils ◽  
Histopathological Changes ◽  
Genetic Changes ◽  
Colonization Ability ◽  
Colonization Factors ◽  
H Pylori

The Mongolian gerbil is an excellent animal model for Helicobacter pylori-induced gastritis in humans. In this study, initially low colonization rates of the H. pylori strains ATCC 43504, SS1, or HP87 inoculated into gerbils caused difficulties in establishing this model. In order to increase the colonization ability and pathogenicity, the clinical HP87 isolate was selected for adaptation to the gerbil stomach by multiple in vivo passages through gerbils. Development of gastritis was examined histologically at 4–52 weeks after infection. The proportion of gerbils which tested positive for H. pylori by culture at four weeks after inoculation gradually increased from 11.1% of gerbils inoculated with HP87 without prior in vivo passage (P0) to 100% of gerbils inoculated with HP87 with seven in vivo passages (P7). In addition, adaptation of HP87 resulted in more severe histopathological changes. Gerbils infected with adapted HP87 (P7) exhibited severe infiltration by monomorphonuclear and polymorphonuclear leukocytes in the mucosa, submucosa, and subserosa of the gastric antrum, as well as epithelial changes consisting of hyperplasia, erosion, and ulceration. Histopathological changes increased in severity from four to 52 weeks after infection. Adaptation of HP87 during its passages through gerbils could be due to genetic changes in bacterial colonization factors. Identification of these changes might be useful to understand the underlying mechanism of gastric adaptation and pathogenesis of H. pylori.

scholarly journals A Syntenic Region Conserved from Fish to Mammalian X Chromosome

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Guijun Guan ◽  
Meisheng Yi ◽  
Tohru Kobayashi ◽  
Yunhan Hong ◽  
Yoshitaka Nagahama
Keyword(s):  
X Chromosome ◽  
Sex Chromosomes ◽  
Random Amplified Polymorphic Dna ◽  
Comparative Genomic ◽  
X Chromosomes ◽  
Ancestral Origin ◽  
Dna Contents ◽  
Determining Factors ◽  
Unpaired Region ◽  
Syntenic Segment

Sex chromosomes bearing the sex-determining gene initiate development along the male or female pathway, no matter which sex is determined by XY male or ZW female heterogamety. Sex chromosomes originate from ancient autosomes but evolved rapidly after the acquisition of sex-determining factors which are highly divergent between species. In the heterogametic male system (XY system), the X chromosome is relatively evolutionary silent and maintains most of its ancestral genes, in contrast to its Y counterpart that has evolved rapidly and degenerated. Sex in a teleost fish, the Nile tilapia (Oreochromis niloticus), is determined genetically via an XY system, in which an unpaired region is present in the largest chromosome pair. We defined the differences in DNA contents present in this chromosome with a two-color comparative genomic hybridization (CGH) and the random amplified polymorphic DNA (RAPD) approach in XY males. We further identified a syntenic segment within this region that is well conserved in several teleosts. Through comparative genome analysis, this syntenic segment was also shown to be present in mammalian X chromosomes, suggesting a common ancestral origin of vertebrate sex chromosomes.

Host species of mistletoes (Loranthaceae and Viscaceae) in Australia

2020 ◽  
Vol 68 (1) ◽  
pp. 1
Author(s):  
Nicole F. Clark ◽  
Jen A. McComb ◽  
Andrew W. Taylor-Robinson
Keyword(s):  
Alien Species ◽  
Host Species ◽  
Current Knowledge ◽  
Sampling Effort ◽  
New Host ◽  
Host Family ◽  
Single Host ◽  
New Hosts ◽  
Host Families ◽  
New Host Species

In order to study the relationships between mistletoes and their host species, comprehensive collections of both mistletoes and hosts are needed. The effect of sampling effort on the estimation of mistletoe host range was demonstrated in a comparison of an inventory of host mistletoe interactions published by Downey in 1998 and a 2019 inventory presented here, which is based on data from collections in the Australian Virtual Herbarium and information in the literature. New hosts were recorded for 93% of the 90 Australian mistletoes. There were 338 previously known hosts recorded to be parasitised by additional mistletoe species, and 317 new host species that were not previously known as mistletoe hosts (25 being alien species). These were from 78 new host genera and 13 new host families. The total number of host species was 1186 within 327 genera from 92 host families. A total of 63% of all Australian mistletoes parasitise species of either Eucalyptus or Acacia or both these genera. The large rise in host species recorded in less than two decades between inventories suggests that current knowledge of hosts is still incomplete, such that further new hosts will be discovered in future. Some mistletoe species show a strong preference to one host family or genus but due to insufficient collecting it is premature to conclude that any of the three species known from a single host are host specific.

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