scholarly journals Global Changes in Mycoplasma gallisepticum Phase-Variable Lipoprotein GenevlhAExpression duringIn VivoInfection of the Natural Chicken Host

2015 ◽  
Vol 84 (1) ◽  
pp. 351-355 ◽  
Author(s):  
K. Pflaum ◽  
E. R. Tulman ◽  
J. Beaudet ◽  
X. Liao ◽  
S. J. Geary
Keyword(s):  
Gene Expression ◽  
Phase Variation ◽  
Mycoplasma Gallisepticum ◽  
Chronic Respiratory Disease ◽  
Etiologic Agent ◽  
Economic Losses ◽  
Global Changes ◽  
Phase Variable ◽  
Content Type ◽  
Host Interaction

Mycoplasma gallisepticumis the primary etiologic agent of chronic respiratory disease in poultry, a disease largely affecting the respiratory tract and causing significant economic losses worldwide. Immunodominant proteins encoded by members of the variable lipoprotein and hemagglutinin (vlhA) gene family are thought to be important for mechanisms ofM. gallisepticum-host interaction, pathogenesis, and immune evasion, but their exact role and the overall nature of their phase variation are unknown. To better understand these mechanisms, we assessed global transcriptomicvlhAgene expression directly fromM. gallisepticumpopulations present on tracheal mucosae during a 7-day experimental infection in the natural chicken host. Here we report differences in both dominant and minorvlhAgene expression levels throughout the first week of infection and starting as early as day 1 postinfection, consistent with a functional role not dependent on adaptive immunity for driving phase variation. Notably, data indicated that, at given time points, specificvlhAgenes were similarly dominant in multiple independent hosts, suggesting a nonstochastic temporal progression of dominantvlhAgene expression in the colonizing bacterial population. The dominant expression of a givenvlhAgene was not dependent on the presence of 12-copy GAA trinucleotide repeats in the promoter region and did not revert to the predominatevlhAgene when no longer faced with host pressures. Overall, these data indicate thatvlhAphase variation is dynamic throughout the earliest stages of infection and that the pattern of dominantvlhAexpression may be nonrandom and regulated by previously unrecognized mechanisms.

scholarly journals Variable Lipoprotein Hemagglutinin A Gene (vlhA) Expression in VariantMycoplasmagallisepticumStrainsIn Vivo

2018 ◽  
Vol 86 (11) ◽  
Author(s):  
K. Pflaum ◽  
E. R. Tulman ◽  
J. Beaudet ◽  
J. Canter ◽  
S. J. Geary
Keyword(s):  
Gene Family ◽  
No Reduction ◽  
Phase Variation ◽  
Chronic Respiratory Disease ◽  
Etiologic Agent ◽  
Economic Losses ◽  
Wild Type ◽  
Exact Role ◽  
Content Type ◽  
Host Interaction

ABSTRACTMycoplasma gallisepticum, the primary etiologic agent of chronic respiratory disease, is a significant poultry pathogen, causing severe inflammation and leading to economic losses worldwide. Immunodominant proteins encoded by the variable lipoprotein and hemagglutinin (vlhA) gene family are thought to be important forM. gallisepticum-host interaction, pathogenesis, and immune evasion, but their exact role remains unknown. Previous work has demonstrated thatvlhAphase variation is dynamic throughout the earliest stages of infection, withvlhA3.03 being the predominantvlhAexpressed during the initial infection, and that the pattern of dominantvlhAexpression may be nonrandom and regulated by previously unrecognized mechanisms. To further investigate this gene family, we assessed thevlhAprofile of two well-characterized vaccine strains, GT5 and Mg7, avlhA3.03 mutant strain, and anM. gallisepticumpopulation expressing an alternative immunodominantvlhA. Here, we report that twoM. gallisepticumvaccine strains show differentvlhAprofiles over the first 2 days of infection compared to that of wild-type Rlow, while the population expressing an alternative immunodominantvlhAgene reverted to a profile indistinguishable from that of wild-type Rlow. Additionally, we observed a slight shift in thevlhAgene expression profile but no reduction in virulence in avlhA3.03 mutant. Taken together, these data further support the hypothesis thatM. gallisepticum vlhAgenes change in a nonstochastic temporal progression of expression and thatvlhA3.03, while preferred, is not required for virulence. Collectively, these data may be important in elucidating mechanisms of colonization and overall pathogenesis ofM. gallisepticum.

scholarly journals Analysis of Invasive NontypeableHaemophilus influenzaeIsolates Reveals Selection for the Expression State of Particular Phase-Variable Lipooligosaccharide Biosynthetic Genes

2019 ◽  
Vol 87 (5) ◽  
Author(s):  
Zachary N. Phillips ◽  
Charles Brizuela ◽  
Amy V. Jennison ◽  
Megan Staples ◽  
Keith Grimwood ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phase Variation ◽  
Phase Variable ◽  
Chronic Infections ◽  
Biosynthetic Genes ◽  
Content Type ◽  
Invasive Infections ◽  
Acetyl Group ◽  
Overt Disease ◽  
Expression Status

ABSTRACTNontypeableHaemophilus influenzae(NTHi) is a major human pathogen, responsible for several acute and chronic infections of the respiratory tract. The incidence of invasive infections caused by NTHi is increasing worldwide. NTHi is able to colonize the nasopharynx asymptomatically, and the exact change(s) responsible for transition from benign carriage to overt disease is not understood. We have previously reported that phase variation (the rapid and reversible ON-OFF switching of gene expression) of particular lipooligosaccharide (LOS) glycosyltransferases occurs during transition from colonizing the nasopharynx to invading the middle ear. Variation in the structure of the LOS is dependent on the ON/OFF expression status of each of the glycosyltransferases responsible for LOS biosynthesis. In this study, we surveyed a collection of invasive NTHi isolates for ON/OFF expression status of seven phase-variable LOS glycosyltransferases. We report that the expression state of the LOS biosynthetic genesoafAON andlic2AOFF shows a correlation with invasive NTHi isolates. We hypothesize that these gene expression changes contribute to the invasive potential of NTHi. OafA expression, which is responsible for the addition of anO-acetyl group onto the LOS, has been shown to impart a phenotype of increased serum resistance and may serve as a marker for invasive NTHi.

scholarly journals Systematic Analysis of REBASE Identifies Numerous Type I Restriction-Modification Systems with Duplicated, Distinct hsdS Specificity Genes That Can Switch System Specificity by Recombination

mSystems ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
John M. Atack ◽  
Chengying Guo ◽  
Thomas Litfin ◽  
Long Yang ◽  
Patrick J. Blackall ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Phase Variation ◽  
Dna Methyltransferases ◽  
Inverted Repeats ◽  
Global Changes ◽  
Type I ◽  
Phase Variable ◽  
Global Methylation ◽  
Content Type ◽  
Restriction Modification

ABSTRACT N6-Adenine DNA methyltransferases associated with some Type I and Type III restriction-modification (R-M) systems are able to undergo phase variation, randomly switching expression ON or OFF by varying the length of locus-encoded simple sequence repeats (SSRs). This variation of methyltransferase expression results in genome-wide methylation differences and global changes in gene expression. These epigenetic regulatory systems are called phasevarions, phase-variable regulons, and are widespread in bacteria. A distinct switching system has also been described in Type I R-M systems, based on recombination-driven changes in hsdS genes, which dictate the DNA target site. In order to determine the prevalence of recombination-driven phasevarions, we generated a program called RecombinationRepeatSearch to interrogate REBASE and identify the presence and number of inverted repeats of hsdS downstream of Type I R-M loci. We report that 3.9% of Type I R-M systems have duplicated variable hsdS genes containing inverted repeats capable of phase variation. We report the presence of these systems in the major pathogens Enterococcus faecalis and Listeria monocytogenes, which could have important implications for pathogenesis and vaccine development. These data suggest that in addition to SSR-driven phasevarions, many bacteria have independently evolved phase-variable Type I R-M systems via recombination between multiple, variable hsdS genes. IMPORTANCE Many bacterial species contain DNA methyltransferases that have random on/off switching of expression. These systems, called phasevarions (phase-variable regulons), control the expression of multiple genes by global methylation changes. In every previously characterized phasevarion, genes involved in pathobiology, antibiotic resistance, and potential vaccine candidates are randomly varied in their expression, commensurate with methyltransferase switching. Our systematic study to determine the extent of phasevarions controlled by invertible Type I R-M systems will provide valuable information for understanding how bacteria regulate genes and is key to the study of physiology, virulence, and vaccine development; therefore, it is critical to identify and characterize phase-variable methyltransferases controlling phasevarions.

scholarly journals GAA Trinucleotide Repeat Region Regulates M9/pMGA Gene Expression in Mycoplasma gallisepticum

2000 ◽  
Vol 68 (2) ◽  
pp. 871-876 ◽  
Author(s):  
Li Liu ◽  
Kevin Dybvig ◽  
Victor S. Panangala ◽  
Vicky L. van Santen ◽  
Christopher T. French
Keyword(s):  
Gene Expression ◽  
Trinucleotide Repeat ◽  
Mycoplasma Gallisepticum ◽  
Avian Host ◽  
Phase Variable ◽  
Repeat Region ◽  
Chromosomal Dna ◽  
Promoter Regions ◽  
Variable Expression ◽  
Gaa Repeats

ABSTRACT Mycoplasma gallisepticum, the cause of chronic respiratory infections in the avian host, possesses a family of M9/pMGA genes encoding an adhesin(s) associated with hemagglutination. Nucleotide sequences of M9/pMGA gene family members indicate extensive sequence similarity in the promoter regions of both the transcribed and silent genes. The mechanism that regulates M9/pMGA gene expression is unknown, but studies have revealed an apparent correlation between gene expression and the number of tandem GAA repeat motifs located upstream of the putative promoter. In this study, transposon Tn4001was used as a vector with the Escherichia coli lacZ gene as the reporter system to examine the role of the GAA repeats in M9/pMGA gene expression in M. gallisepticum. A 336-bp M9 gene fragment (containing the GAA repeat region, the promoter, and the translation start codon) was amplified by PCR, ligated with alacZ gene from E. coli, and inserted into the Tn4001-containing plasmid pISM2062. This construct was transformed into M. gallisepticum PG31. Transformants were filter cloned on agar supplemented with 5-bromo-4-chloro-3-indolyl-β-d-galactopyranoside (X-Gal) to monitor lacZ gene expression on the basis of blue/white color selection. Several cycles of filter cloning resulted in cell lineages in which lacZ gene expression alternated between the On and Off states in successive generations of progeny clones. The promoter regions of the M9-lacZ hybrid genes of individual progeny clones were amplified by PCR and sequenced. The only differences between the promoter regions of the blue and white colonies were in the number of GAA repeats. Clones that expressedlacZ had exactly 12 tandem copies of the GAA repeat. Clones that did not express lacZ invariably had either more than 12 (14 to 16) or fewer than 12 (5 to 11) GAA repeats. Southern analysis of M. gallisepticum chromosomal DNA confirmed that the phase-variable expression of the lacZ reporter gene was not caused by Tn4001 transposition. These data strongly indicate that changes in the length of the GAA repeat region are responsible for regulating M9/pMGA gene expression.

scholarly journals Role of the GapA and CrmA Cytadhesins of Mycoplasma gallisepticum in Promoting Virulence and Host Colonization

2013 ◽  
Vol 81 (5) ◽  
pp. 1618-1624 ◽  
Author(s):  
Ivana Indiková ◽  
Peter Much ◽  
László Stipkovits ◽  
Karin Siebert-Gulle ◽  
Michael P. Szostak ◽  
...  
Keyword(s):  
Point Mutation ◽  
Mycoplasma Gallisepticum ◽  
Chronic Respiratory Disease ◽  
Host Colonization ◽  
Content Type ◽  
Inner Organs ◽  
Avian Pathogen ◽  
Low Passage

ABSTRACTMycoplasma gallisepticumis an important avian pathogen that commonly induces chronic respiratory disease in chicken. To better understand the mycoplasma factors involved in host colonization, chickens were infected via aerosol with two hemadsorption-negative (HA−) mutants, mHAD3 and RCL2, that were derived from a low passage of the pathogenic strain R (Rlow) and are both deficient in the two major cytadhesins GapA and CrmA. After 9 days of infection, chickens were monitored for air sac lesions and for the presence of mycoplasmas in various organs. The data showed that mHAD3, in which thecrmAgene has been disrupted, did not promote efficient colonization or significant air sac lesions. In contrast, the spontaneous HA−RCL2 mutant, which contains a point mutation in thegapAstructural gene, successfully colonized the respiratory tract and displayed an attenuated virulence compared to that of Rlow. It has previously been shownin vitrothat the point mutation of RCL2 spontaneously reverts with a high frequency, resulting in on-and-off switching of the HA phenotype. Detailed analyses further revealed that such an event is not responsible for the observedin vivooutcome, since 98.4% of the mycoplasma populations recovered from RCL2-infected chickens still display the mutation and the associated phenotype. Unlike Rlow, however, RCL2 was unable to colonize inner organs. These findings demonstrate the major role played by the GapA and CrmA proteins inM. gallisepticumhost colonization and virulence.

scholarly journals Phasevarions Mediate Epigenetic Regulation of Antimicrobial Susceptibility in Neisseria meningitidis

2014 ◽  
Vol 58 (7) ◽  
pp. 4219-4221 ◽  
Author(s):  
Freda E.-C. Jen ◽  
Kate L. Seib ◽  
Michael P. Jennings
Keyword(s):  
Gene Expression ◽  
Neisseria Meningitidis ◽  
Epigenetic Regulation ◽  
Antimicrobial Susceptibility ◽  
Bacterial Pathogens ◽  
Phase Variation ◽  
Dna Methyltransferases ◽  
Global Methylation ◽  
Content Type ◽  
Multiple Genes

ABSTRACTPhase variation is a common feature of host-adapted bacterial pathogens such asNeisseria meningitidis. Recently, we reported that this rapid on/off switching of gene expression occurs in DNA methyltransferases, altering expression in multiple genes via changes in global methylation. In the current study, we compared MIC values of strains with ModA11, ModA12, and ModD1 phasevarions, revealing MIC differences due to ModA11 and ModA12 switching, with a ModA11_OFF strain showing 4-fold reduced susceptibilities to ceftazidime and ciprofloxacin.

scholarly journals Phenotypic Switching in Mycoplasma gallisepticum Hemadsorption Is Governed by a High-Frequency, Reversible Point Mutation

2003 ◽  
Vol 71 (3) ◽  
pp. 1265-1273 ◽  
Author(s):  
Florian Winner ◽  
Ivana Markovà ◽  
Peter Much ◽  
Albin Lugmair ◽  
Karin Siebert-Gulle ◽  
...  
Keyword(s):  
High Frequency ◽  
Stop Codon ◽  
Phase Variation ◽  
Mycoplasma Gallisepticum ◽  
Chronic Respiratory Disease ◽  
Transcription Unit ◽  
Phenotypic Switching ◽  
Base Substitution ◽  
Mutational Event ◽  
Repeated Motifs

ABSTRACT Mycoplasma gallisepticum is a flask-shaped organism that commonly induces chronic respiratory disease in chickens and infectious sinusitis in turkeys. Phenotypic switching in M. gallisepticum hemadsorption (HA) was found to correlate with phase variation of the GapA cytadhesin concurrently with that of the CrmA protein, which exhibits cytadhesin-related features and is encoded by a gene located downstream of the gapA gene as part of the same transcription unit. In clones derived from strain Rlow, detailed genetic analyses further revealed that on-off switching in GapA expression is governed by a reversible base substitution occurring at the beginning of the gapA structural gene. In HA− variants, this event generates a stop codon that results in the premature termination of GapA translation and consequently affects the expression of CrmA. Sequences flanking the mutation spot do not feature any repeated motifs that could account for error-prone mutation via DNA slippage and the exact mechanism underlying this high-frequency mutational event remains to be elucidated. An HA− mutant deficient in producing CrmA, mHAD3, was obtained by disrupting the crmA gene by using transposition mutagenesis. Despite a fully functional gapA gene, the amount of GapA detected in this mutant was considerably lower than in HA+ clonal variants, suggesting that, in absence of CrmA, GapA might be subjected to a higher turnover.

scholarly journals Transcriptome Profiling of Botrytis cinerea Conidial Germination Reveals Upregulation of Infection-Related Genes during the Prepenetration Stage

2013 ◽  
Vol 12 (4) ◽  
pp. 614-626 ◽  
Author(s):  
Michaela Leroch ◽  
Astrid Kleber ◽  
Evelyn Silva ◽  
Tina Coenen ◽  
Dieter Koppenhöfer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Botrytis Cinerea ◽  
Transcriptome Profiling ◽  
Gray Mold ◽  
Secretory Proteins ◽  
Global Changes ◽  
Lytic Enzymes ◽  
Chitin Deacetylase ◽  
Specific Expression ◽  
Content Type

ABSTRACTBotrytis cinereacauses gray mold on a great number of host plants. Infection is initiated by airborne conidia that invade the host tissue, often by penetration of intact epidermal cells. To mimic the surface properties of natural plant surfaces, conidia were incubated on apple wax-coated surfaces, resulting in rapid germination and appressorium formation. Global changes in gene expression were analyzed by microarray hybridization between conidia incubated for 0 h (dormant), 1 h (pregermination), 2.5 h (postgermination), 4 h (appressoria), and 15 h (early mycelium). Considerable changes were observed, in particular between 0 h and 1 h. Genes induced during germination were enriched in those genes encoding secreted proteins, including lytic enzymes. Comparison of wild-type and a nonpathogenic MAP kinase mutant (bmp1) revealed marked differences in germination-related gene expression, in particular related to secretory proteins. Using promoter-GFP reporter strains, we detected a strictly germination-specific expression pattern of a putative chitin deacetylase gene (cda1). In contrast, a cutinase gene (cutB) was found to be expressed only in the presence of plant lipids, in a developmentally less stringent pattern. We also identified a coregulated gene cluster possibly involved in secondary metabolite synthesis which was found to be controlled by a transcription factor also encoded in this cluster. Our data demonstrate that early conidial development inB. cinereais accompanied by rapid shifts in gene expression that prepare the fungus for germ tube outgrowth and host cell invasion.

scholarly journals Identification of Strain-Specific Sequences That Distinguish a Mycoplasma gallisepticum Vaccine Strain from Field Isolates

2016 ◽  
Vol 55 (1) ◽  
pp. 244-252 ◽  
Author(s):  
Camir Ricketts ◽  
Larissa Pickler ◽  
John Maurer ◽  
Saravanaraj Ayyampalayam ◽  
Maricarmen García ◽  
...  
Keyword(s):  
Vaccine Strain ◽  
Reference Genome ◽  
Hypothetical Protein ◽  
Mycoplasma Gallisepticum ◽  
Economic Losses ◽  
Poultry Production ◽  
Content Type ◽  
Field Isolates ◽  
Avian Mycoplasmosis ◽  
A Cell

ABSTRACTDespite attempts to control avian mycoplasmosis through management, vaccination, and surveillance,Mycoplasma gallisepticumcontinues to cause significant morbidity, mortality, and economic losses in poultry production. Live attenuated vaccines are commonly used in the poultry industry to control avian mycoplasmosis; unfortunately, some vaccines may revert to virulence and vaccine strains are generally difficult to distinguish from natural field isolates. In order to identify genome differences among vaccine revertants, vaccine strains, and field isolates, whole-genome sequencing of theM. gallisepticumvaccine strain ts-11 and several “ts-11-like” strains isolated from commercial flocks was performed using Illumina and 454 pyrosequencing and the sequenced genomes compared to theM. gallisepticumRlowreference genome. The collective contigs for each strain were annotated using the fully annotatedMycoplasmareference genome. The analysis revealed genetic differences amongvlhAalleles, as well as among genes annotated as coding for a cell wall surface anchor protein (mg0377) and a hypothetical protein gene,mg0359, unique toM. gallisepticumts-11 vaccine strain. PCR protocols were designed to target 5 sequences unique to theM. gallisepticumts-11 strain:vlhA3.04a,vlhA3.04b,vlhA3.05,mg0377, andmg0359. All ts-11 isolates were positive for the five gene alleles tested by PCR; however, 5 to 36% of field isolates were also positive for at least one of the alleles tested. A combination of PCR tests forvlhA3.04a,vlhA3.05, andmg0359was able to distinguish theM. gallisepticumts-11 vaccine strain from field isolates. This method will further supplement current approaches to quickly distinguishM. gallisepticumvaccine strains from field isolates.

scholarly journals An In Vitro Antibacterial Activity Test of Meniran Herbs’(Phyllanthus Niruri L.) Ethanol ExtractAgainst Mycoplasma gallisepticum causes Chronic Respiratory Disease (CRD) in Broiler Chickens

2017 ◽  
Vol 3 (6) ◽  
pp. 48 ◽  
Author(s):  
Emy Koestanti Sabdoningrum ◽  
Sri Hidanah ◽  
Retno Sri Wahjuni ◽  
Sri Chusniati ◽  
Arimbi Arimbi
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Respiratory Disease ◽  
Broiler Chickens ◽  
Inhibitory Concentration ◽  
Mycoplasma Gallisepticum ◽  
Chronic Respiratory Disease ◽  
Economic Losses ◽  
Dilution Method ◽  
Phyllanthus Niruri

Chronic Respiratory Disease (CRD) is a chicken respiratory disease that attacks both broilers and layers. Chronic Respiratory Disease (CRD) has important economic significance in the intensification of chicken farms because this disease can cause huge economic losses. Meniran plant (Phyllanthus niruri Linn) is one of the plants that can be used as prevention and alternative treatment as a substitute of antibiotic caused by Mycoplasma galisepticum causes Chronic Respiratory Disease (CRD) in broiler chickens. The chemicals contained in meniran include tannins, saponins, alkaloids as antibacterials. The purpose of this study is to determine the activity of meniran herbs’ (Phyllanthus Niruri Linn) as antibacterial to eradicate Mycoplasma galisepticum. The method of this study is dilution method which included Minimum Inhibitory Concentration [MIC) and Minimum Bactericidal Concentration (MBC). Minimum Inhibitory Concentration [MIC) was taken by making the concentration of meniran extract as much 65%, 62,5%; 60%; 55%; 50%; 45%; 40%. It was then added Mycoplasma gallisepticum bacteria. The result of this study is Meniran’s activation test on Mycoplasma galisepticum obtained a dose of 62,5% could eradicate Mycoplasma galisepticum causes Chronic Respiratory Disease (CRD) in broiler chickens. Meniran herbs’ (Phyllanthus niruri linn) is effective as antibacterial at concentrations of 30% against Mycoplasma gallisepticum causes Chronic Respiratory Disease (CRD) in broiler chickens. Keywords: Meniran herbs’ (Phyllanthus Niruri Linn), Mycoplasma Galisepticum, Chronic Respiratory Disease (CRD)

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