scholarly journals Growth and Development of Tetracycline-ResistantChlamydia suis

2001 ◽  
Vol 45 (8) ◽  
pp. 2198-2203 ◽  
Author(s):  
J. Lenart ◽  
A. A. Andersen ◽  
D. D. Rockey
Keyword(s):  
Tissue Culture ◽  
Chlamydia Trachomatis ◽  
Sus Scrofa ◽  
Growth And Development ◽  
Clinical Importance ◽  
Developmental Cycle ◽  
Front Line ◽  
Single Inclusion ◽  
Swine Strain ◽  
Sequential Infection

ABSTRACT Tetracycline (TET) is a front-line antibiotic for the treatment of chlamydial infections in both humans and animals, and the emergence of TET-resistant (Tetr) Chlamydia is of significant clinical importance. Recently, several Tetrchlamydial strains have been isolated from swine (Sus scrofa) raised in production facilities in Nebraska. Here, the intracellular development of two Tetr strains, R19 and R27, is characterized through the use of tissue culture and immunofluorescence. The strains grow in concentrations of up to 4 μg of TET/ml, while a TET-sensitive (Tets) swine strain (S45) and a strain of the human serovar L2 (LGV-434) grow in up to 0.1 μg of TET/ml. Although inclusions form in the presence of TET, many contain large aberrant reticulate bodies (RBs) that do not differentiate into infectious elementary bodies. The percentage of inclusions containing typical developmental forms decreases with increasing TET concentrations, and at 3 μg of TET/ml 100% of inclusions contain aberrant RBs. However, upon removal of TET the aberrant RBs revert to typical RBs, and a productive developmental cycle ensues. In addition, inclusions were found that contained bothC. suis R19 and Chlamydia trachomatis L2 after sequential infection, demonstrating that two biologically distinct chlamydial strains could both develop within a single inclusion.

scholarly journals GrgA controls Chlamydia trachomatis growth and development by regulating expression of transcription factors Euo and HrcA

2020 ◽  
Author(s):  
Wurihan Wurihan ◽  
Yi Zou ◽  
Alec M. Weber ◽  
Korri Weldon ◽  
Yehong Huang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcription Factors ◽  
Chlamydia Trachomatis ◽  
Virulence Factor ◽  
Growth And Development ◽  
Developmental Cycle ◽  
Mrna Levels ◽  
Late Genes ◽  
Transcriptomic Changes

ABSTRACTThe obligate intracellular bacterium Chlamydia trachomatis is an important human pathogen whose biphasic developmental cycle consists of an infectious elementary body and a replicative reticulate body. Whereas σ66, the primary sigma factor, is necessary for transcription of most chlamydial genes throughout the developmental cycle, σ28 is required for expression of some late genes. We previously showed that the Chlamydia-specific transcription factor GrgA physically interacts with both of these sigma factors and activates transcription from σ66- and σ28-dependent promoters in vitro. Here, we investigate the organismal functions of GrgA. We show that GrgA overexpression decreased RB proliferation via time-dependent transcriptomic changes. Significantly, σ66-dependent genes that code for two important transcription repressors are among the direct targets of GrgA. One of these repressors is Euo, which prevents the expression of late genes during early phases. The other is HrcA, which regulates gene expression in response to heat shock. The direct regulon of GrgA also includes a σ28-dependent gene that codes for the putative virulence factor PmpI. Conditional overexpression of Euo and HrcA also inhibited chlamydial growth and affected GrgA expression. Transcriptomic studies suggest that GrgA, Euo, and HrcA have distinct but overlapping indirect regulons. Furthermore, overexpression of either GrgA leads to decreased expression of numerous tRNAs. These findings indicate that a GrgA-mediated transcriptional regulatory network controls C. trachomatis growth and development.IMPORTANCEChlamydia trachomatis is the most prevalent sexually transmitted bacterial pathogen worldwide and is a leading cause of preventable blindness in under-developed areas as well as developed countries. Previous studies showed that the novel transcription factor GrgA activated chlamydial gene transcription in vitro, but did not addressed the organismal function of GrgA. Here, we demonstrate growth inhibition in C. trachomatis engineered to conditionally overexpress GrgA. GrgA overexpression immediately increases the expression of two other critical transcription factors (Euo and HrcA) and a candidate virulence factor (PmpI), among several other genes. We also reveal chlamydial growth reduction and transcriptomic changes including decreased GrgA mRNA levels in response to either Euo or HrcA overexpression. Thus, the transcription network controlled by GrgA likely plays a crucial role in chlamydial growth and pathogenesis.

scholarly journals The ClpX and ClpP2 Orthologs of Chlamydia trachomatis Perform Discrete and Essential Functions in Organism Growth and Development

2019 ◽  
Author(s):  
Nicholas A. Wood ◽  
Amanda M. Blocker ◽  
Mohamed A. Seleem ◽  
Martin Conda-Sheridan ◽  
Derek J. Fisher ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Protein Turnover ◽  
Growth And Development ◽  
Drug Targets ◽  
Developmental Cycle ◽  
Transmitted Infection ◽  
Plasmid Copy ◽  
Cycle Progression ◽  
Aaa Atpase

Abstract:Chlamydia trachomatis (Ctr) is an obligate intracellular bacterium that undergoes a complex developmental cycle in which the bacterium differentiates between two functionally and morphologically distinct forms, the EB and RB, each of which expresses its own specialized repertoire of proteins. Both primary (EB to RB) and secondary (RB to EB) differentiation require protein turnover, and we hypothesize that proteases are critical for mediating differentiation. The Clp protease system is well conserved in bacteria and important for protein turnover. Minimally, the system relies on a serine protease subunit, ClpP, and a AAA+ ATPase, such as ClpX, that recognizes and unfolds substrates for ClpP degradation. In Chlamydia, ClpX is encoded within an operon 3’ to clpP2. We present evidence that the chlamydial ClpX and ClpP2 orthologs are essential to organism viability and development. We demonstrate here that chlamydial ClpX is a functional ATPase and forms the expected homohexamer in vitro. Overexpression of a ClpX mutant lacking ATPase activity had a limited impact on DNA replication or secondary differentiation but, nonetheless, reduced EB viability with observable defects in EB morphology noted. Conversely, the overexpression of a catalytically inactive ClpP2 mutant significantly impacted developmental cycle progression by reducing the overall number of organisms. Blocking clpP2X transcription using CRISPR interference led to a decrease in bacterial growth, and this effect was complemented in trans by a plasmid copy of clpP2. Taken together, our data indicate that ClpX and the associated ClpP2 serve distinct functions in chlamydial developmental cycle progression and differentiation.ImportanceChlamydia trachomatis is the leading cause of infectious blindness globally and the most reported bacterial sexually transmitted infection both domestically and internationally. Given the economic burden, the lack of an approved vaccine, and the use of broad-spectrum antibiotics for treatment of infections, an understanding of chlamydial growth and development is critical for the advancement of novel, targeted antibiotics. The Clp proteins comprise an important and conserved protease system in bacteria. Our work highlights the importance of the chlamydial Clp proteins to this clinically important bacterium. Additionally, our study implicates the Clp system playing an integral role in chlamydial developmental cycle progression, which may help establish models of how Chlamydia spp. and other bacteria progress through their respective developmental cycles. Our work also contributes to a growing body of Clp-specific research that underscores the importance and versatility of this system throughout bacterial evolution and further validates Clp proteins as drug targets.

scholarly journals The ClpX and ClpP2 Orthologs of Chlamydia trachomatis Perform Discrete and Essential Functions in Organism Growth and Development

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Nicholas A. Wood ◽  
Amanda M. Blocker ◽  
Mohamed A. Seleem ◽  
Martin Conda-Sheridan ◽  
Derek J. Fisher ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Protein Turnover ◽  
Growth And Development ◽  
Developmental Cycle ◽  
Transmitted Infection ◽  
Plasmid Copy ◽  
Cycle Progression ◽  
Content Type ◽  
Aaa Atpase

ABSTRACT Chlamydia trachomatis is an obligate intracellular bacterium that undergoes a complex developmental cycle in which the bacterium differentiates between two functionally and morphologically distinct forms, the elementary body (EB) and reticulate body (RB), each of which expresses its own specialized repertoire of proteins. Both primary (EB to RB) and secondary (RB to EB) differentiations require protein turnover, and we hypothesize that proteases are critical for mediating differentiation. The Clp protease system is well conserved in bacteria and important for protein turnover. Minimally, the system relies on a serine protease subunit, ClpP, and an AAA+ ATPase, such as ClpX, that recognizes and unfolds substrates for ClpP degradation. In Chlamydia, ClpX is encoded within an operon 3′ to clpP2. We present evidence that the chlamydial ClpX and ClpP2 orthologs are essential to organism viability and development. We demonstrate here that chlamydial ClpX is a functional ATPase and forms the expected homohexamer in vitro. Overexpression of a ClpX mutant lacking ATPase activity had a limited impact on DNA replication or secondary differentiation but, nonetheless, reduced EB viability with observable defects in EB morphology noted. Conversely, overexpression of a catalytically inactive ClpP2 mutant significantly impacted developmental cycle progression by reducing the overall number of organisms. Blocking clpP2X transcription using CRISPR interference led to a decrease in bacterial growth, and this effect was complemented in trans by a plasmid copy of clpP2. Taken together, our data indicate that ClpX and the associated ClpP2 serve distinct functions in chlamydial developmental cycle progression and differentiation. IMPORTANCE Chlamydia trachomatis is the leading cause of infectious blindness globally and the most reported bacterial sexually transmitted infection both domestically and internationally. Given the economic burden, the lack of an approved vaccine, and the use of broad-spectrum antibiotics for treatment of infections, an understanding of chlamydial growth and development is critical for the advancement of novel targeted antibiotics. The Clp proteins comprise an important and conserved protease system in bacteria. Our work highlights the importance of the chlamydial Clp proteins to this clinically important bacterium. Additionally, our study implicates the Clp system playing an integral role in chlamydial developmental cycle progression, which may help establish models of how Chlamydia spp. and other bacteria progress through their respective developmental cycles. Our work also contributes to a growing body of Clp-specific research that underscores the importance and versatility of this system throughout bacterial evolution and further validates Clp proteins as drug targets.

scholarly journals Effects ofMentha suaveolensEssential Oil onChlamydia trachomatis

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Rosa Sessa ◽  
Marisa Di Pietro ◽  
Fiorenzo De Santis ◽  
Simone Filardo ◽  
Rino Ragno ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Substantial Reduction ◽  
Developmental Cycle ◽  
Elementary Body ◽  
Promising Candidate ◽  
Common Cause ◽  
Sexually Transmitted ◽  
Reticulate Body ◽  
Preventative Strategy

Chlamydia trachomatis, the most common cause of sexually transmitted bacterial infection worldwide, has a unique biphasic developmental cycle alternating between the infectious elementary body and the replicative reticulate body.C. trachomatisis responsible for severe reproductive complications including pelvic inflammatory disease, ectopic pregnancy, and obstructive infertility. The aim of our study was to evaluate whetherMentha suaveolensessential oil (EOMS) can be considered as a promising candidate for preventingC. trachomatisinfection. Specifically, we investigated thein vitroeffects of EOMS towardsC. trachomatisanalysing the different phases of chlamydial developmental cycle. Our results demonstrated that EOMS was effective towardsC. trachomatis, whereby it not only inactivated infectious elementary bodies but also inhibited chlamydial replication. Our study also revealed the effectiveness of EOMS, in combination with erythromycin, towardsC. trachomatiswith a substantial reduction in the minimum effect dose of antibiotic. In conclusion, EOMS treatment may represent a preventative strategy since it may reduceC. trachomatistransmission in the population and, thereby, reduce the number of new chlamydial infections and risk of developing of severe sequelae.

scholarly journals Chlamydial infection and disease in the koala

2005 ◽  
Vol 26 (2) ◽  
pp. 65 ◽  
Author(s):  
Peter Timms
Keyword(s):  
Chlamydia Trachomatis ◽  
Chlamydial Infection ◽  
Developmental Cycle ◽  
Elementary Body ◽  
Obligate Intracellular ◽  
Molecular Approaches ◽  
Reticulate Body ◽  
Wide Range ◽  
The Family ◽  
Serious Disease

Chlamydiae are obligate intracellular bacterial pathogens able to infect and cause serious disease in humans, birds and a remarkably wide range of warm and cold-blooded animals. The family Chlamydiaciae have traditionally been defined by their unique biphasic developmental cycle, involving the interconversion between an extracellular survival form, the elementary body and an intracellular replicative form, the reticulate body. However, as with many other bacteria, molecular approaches including 16SrRNA sequence are becoming the standard of choice. As a consequence, the chlamydiae are in a taxonomic state of flux. Prior to 1999, the family Chlamydiaceae consisted of one genus, Chlamydia, and four species, Chlamydia trachomatis, C. psittaci, C. pecorum and C. pneumoniae. In 1999, Everett et al proposed a reclassification of Chlamydia into two genera (Chlamydia and Chlamydophila) and nine species (Chlamydia trachomatis, C. suis, and C. muridarum and Chlamydophila psittaci, C. pneumoniae, C. felis, C. pecorum, C. abortus, and C. caviae). While some of these species are thought to be host specific (C. suis ? pigs, C. muridarum ? mice, C. felis ? cats, C. caviae ? guinea pigs) many are known to infect and cause disease in a wide range of hosts.

scholarly journals Quantitative Monitoring of the Chlamydia trachomatis Developmental Cycle Using GFP-Expressing Bacteria, Microscopy and Flow Cytometry

PLoS ONE ◽  
2014 ◽  
Vol 9 (6) ◽  
pp. e99197 ◽  
Author(s):  
François Vromman ◽  
Marc Laverrière ◽  
Stéphanie Perrinet ◽  
Alexandre Dufour ◽  
Agathe Subtil
Keyword(s):  
Flow Cytometry ◽  
Chlamydia Trachomatis ◽  
Developmental Cycle ◽  
Quantitative Monitoring

scholarly journals Transcriptional Expression of the ompA, cpaf, tarp, and tox Genes of Chlamydia trachomatis Clinical Isolates at Different Stages of the Developmental Cycle

2019 ◽  
Vol 7 (6) ◽  
pp. 153 ◽  
Author(s):  
Suvi Korhonen ◽  
Kati Hokynar ◽  
Laura Mannonen ◽  
Jorma Paavonen ◽  
Eija Hiltunen-Back ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chlamydia Trachomatis ◽  
Cultured Cells ◽  
Expression Patterns ◽  
Clinical Isolates ◽  
Gene Expression Patterns ◽  
Developmental Cycle ◽  
Passage Number ◽  
Low Passage ◽  
Reference Strains

The transcriptional gene expression patterns of Chlamydia trachomatis have mainly been studied using reference strains propagated in cultured cells. Here, using five low-passage-number C. trachomatis clinical isolates that originated from asymptomatic or symptomatic female patients, the in vitro expression of the ompA, cpaf, tarp, and tox genes was studied with reverse transcriptase real-time PCR during the chlamydial developmental cycle. We observed dissimilarities in the gene expression patterns between the low-passage-number clinical isolates and the reference strains. The expression of ompA and the peak of the tox expression were observed earlier in the reference strains than in most of the clinical isolates. The expression of cpaf was high in the reference strains compared with the clinical isolates at the mid-phase (6–24 hours post infection) of the developmental cycle. All of the strains had a rather similar tarp expression profile. Four out of five clinical isolates exhibited slower growth kinetics compared with the reference strains. The use of low-passage-number C. trachomatis clinical isolates instead of reference strains in the studies might better reflect the situation in human infection.

scholarly journals STUDIES ON THE PSITTACOSIS-LYMPHOGRANULOMA GROUP

1952 ◽  
Vol 96 (3) ◽  
pp. 233-246 ◽  
Author(s):  
Anthony J. Girardi ◽  
Emma G. Allen ◽  
M. Michael Sigel
Keyword(s):  
Tissue Culture ◽  
Infectious Virus ◽  
Virus Titer ◽  
Subsequent Development ◽  
Developmental Cycle ◽  
In Ovo ◽  
Virus Inoculation ◽  
Virus Adsorption ◽  
Infectious Form

The pattern of growth of meningopneumonitis virus in vitro seemed to be similar to that occurring in ovo and thus the initial stages of development, the adsorption and the latent periods, were investigated by the use of tissue culture procedures. The initial increment of infectivity in allantoic membrane suspensions following virus inoculation in ovo was due to prolonged adsorption of virus and not to immediate virus reproduction. The length of the adsorption period varied with the virus dilution employed. The reduction of virus titer in allantoic membrane suspensions subsequent to adsorption was due to a change of infectious virus to a non-infectious form and this seemed to be a part of the normal developmental cycle of the virus. The possible causes for both prolonged virus adsorption and for the subsequent development of a non-infectious form are discussed.

scholarly journals The Future of Restorative Neurosciences in Stroke: Driving the Translational Research Pipeline From Basic Science to Rehabilitation of People After Stroke

2008 ◽  
Vol 23 (2) ◽  
pp. 97-107 ◽  
Author(s):  
◽  
Binith Cheeran ◽  
Leonardo Cohen ◽  
Bruce Dobkin ◽  
Gary Ford ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Translational Research ◽  
Basic Science ◽  
Clinical Importance ◽  
Small Scale ◽  
Front Line ◽  
Pressure Groups ◽  
The United Kingdom ◽  
Public Sector Research

Background. Major advances during the past 50 years highlight the immense potential for restoration of function after neural injury, even in the damaged adult human brain. Yet, the translation of these advances into clinically useful treatments is painstakingly slow. Objective. Here, we consider why the traditional model of a “translational research pipeline” that transforms basic science into novel clinical practice has failed to improve rehabilitation practice for people after stroke. Results. We find that (1) most treatments trialed in vitro and in animal models have not yet resulted in obviously useful functional gains in patients; (2) most clinical trials of restorative treatments after stroke have been limited to small-scale studies; (3) patient recruitment for larger clinical trials is difficult; (4) the determinants of patient outcomes and what patients want remain complex and ill-defined, so that basic scientists have no clear view of the clinical importance of the problems that they are addressing; (5) research in academic neuroscience centers is poorly integrated with practice in front-line hospitals and the community, where the majority of patients are treated; and (6) partnership with both industry stakeholders and patient pressure groups is poorly developed, at least in the United Kingdom where research in the translational restorative neurosciences in stroke depends on public sector research funds and private charities. Conclusions. We argue that interaction between patients, front-line clinicians, and clinical and basic scientists is essential so that they can explore their different priorities, skills, and concerns. These interactions can be facilitated by funding research consortia that include basic and clinical scientists, clinicians and patient/carer representatives with funds targeted at those impairments that are major determinants of patient and carer outcomes. Consortia would be instrumental in developing a lexicon of common methods, standardized outcome measures, data sharing and long-term goals. Interactions of this sort would create a research-friendly, rather than only target-led, culture in front-line stroke rehabilitation services.

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