scholarly journals Biology and intracellular life of chlamydia

2011 ◽  
Vol 64 (11-12) ◽  
pp. 561-564 ◽  
Author(s):  
Maja Vivoda ◽  
Ivana Cirkovic ◽  
Djordje Aleksic ◽  
Lazar Ranin ◽  
Slobodanka Djukic
Keyword(s):  
Host Cell ◽  
Active Form ◽  
Developmental Cycle ◽  
Elementary Body ◽  
Reticulate Body ◽  
Long Time ◽  
Developmental Form ◽  
Obligate Intracellular Bacteria ◽  
Infectious Form

Introduction. Chlamydiae are Gram-negative obligate intracellular bacteria. The developmental cycle of Chlamydiae is specific and different from other bacteria. The elementary body is the infectious form of the organism, responsible for attaching to the target host cell and promoting its entry. The reticulate body is the larger, metabolically active form of the organism, synthesizing deoxyribonucleic acid, ribonucleic acid and proteins. The elementary body and reticulate body represent evolutionary adaptations to extracellular and intracellular environments. Intracellular persistence of Chlamydia. Predisposition of Chlamydia to persist within the host cell has been recognized as a major factor in the pathogenesis of chlamydial disease. The persistence implies a long-term association between chlamydiae and their host cell that may not manifest as clinically recognizable disease. The ability of chlamydia to remain within one morphological state for a long time in response to exogenous factors suggests an innate ability of these organisms to persist intracellulary in a unique developmental form. Chlamydiae induce interferon ? and exhibit growth inhibition in their presence. While the high levels of interferon ? completely restrict the development of chlamydia, its low levels induce the development of morphologically aberrant intracellular forms. The persistent forms contain reduced levels of major outer membrane protein but high levels of chlamydial heat shock protein. Conclusion. Immunopathogenesis of chlamydial infection is one of the main focal points of current research into Chlamydia. Chlamydial infections are highly prevalent, usually asymptomatic and associated with serious sequelae. Screening programmes are the most important in the prevention of a long-term sequele.

scholarly journals Initial Characterization of the Two ClpP Paralogs ofChlamydia trachomatisSuggests Unique Functionality for Each

2018 ◽  
Vol 201 (2) ◽  
Author(s):  
Nicholas A. Wood ◽  
Krystal Y. Chung ◽  
Amanda M. Blocker ◽  
Nathalia Rodrigues de Almeida ◽  
Martin Conda-Sheridan ◽  
...  
Keyword(s):  
Host Cells ◽  
Developmental Cycle ◽  
Intracellular Bacteria ◽  
Clp Protease ◽  
Content Type ◽  
Sexually Transmitted ◽  
Obligate Intracellular ◽  
Developmental Form ◽  
Obligate Intracellular Bacteria

ABSTRACTMembers ofChlamydiaare obligate intracellular bacteria that differentiate between two distinct functional and morphological forms during their developmental cycle, elementary bodies (EBs) and reticulate bodies (RBs). EBs are nondividing small electron-dense forms that infect host cells. RBs are larger noninfectious replicative forms that develop within a membrane-bound vesicle, termed an inclusion. Given the unique properties of each developmental form of this bacterium, we hypothesized that the Clp protease system plays an integral role in proteomic turnover by degrading specific proteins from one developmental form or the other.Chlamydiaspp. have five uncharacterizedclpgenes,clpX,clpC, twoclpPparalogs, andclpB. In other bacteria, ClpC and ClpX are ATPases that unfold and feed proteins into the ClpP protease to be degraded, and ClpB is a deaggregase. Here, we focused on characterizing the ClpP paralogs. Transcriptional analyses and immunoblotting determined that these genes are expressed midcycle. Bioinformatic analyses of these proteins identified key residues important for activity. Overexpression of inactiveclpPmutants inChlamydiaspp. suggested independent function of each ClpP paralog. To further probe these differences, we determined interactions between the ClpP proteins using bacterial two-hybrid assays and native gel analysis of recombinant proteins. Homotypic interactions of the ClpP proteins, but not heterotypic interactions between the ClpP paralogs, were detected. Interestingly, protease activity of ClpP2, but not ClpP1, was detectedin vitro. This activity was stimulated by antibiotics known to activate ClpP, which also blocked chlamydial growth. Our data suggest the chlamydial ClpP paralogs likely serve distinct and critical roles in this important pathogen.IMPORTANCEChlamydia trachomatisis the leading cause of preventable infectious blindness and of bacterial sexually transmitted infections worldwide. Chlamydiae are developmentally regulated obligate intracellular pathogens that alternate between two functional and morphologic forms, with distinct repertoires of proteins. We hypothesize that protein degradation is a critical aspect to the developmental cycle. A key system involved in protein turnover in bacteria is the Clp protease system. Here, we characterized the two chlamydial ClpP paralogs by examining their expression inChlamydiaspp., their ability to oligomerize, and their proteolytic activity. This work will help understand the evolutionarily diverse Clp proteases in the context of intracellular organisms, which may aid in the study of other clinically relevant intracellular bacteria.

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.

Chlamydiosis

2011 ◽  
Author(s):  
Margaret Sillis ◽  
David Longbottom
Keyword(s):  
Control Strategies ◽  
Risk Groups ◽  
Developmental Cycle ◽  
Zoonotic Infections ◽  
The United Kingdom ◽  
Reticulate Body ◽  
Wide Range ◽  
Poultry Processing ◽  
Variable Success ◽  
Obligate Intracellular Bacteria

Chlamydial pathogens cause a wide-range of infections and disease, known as chlamydioses, in humans, other mammals and birds. The causative organisms are Gram-negative obligate intracellular bacteria that undergo a unique biphasic developmental cycle involving the infectious elementary body and the metabolically-active, non-infectious reticulate body. At least two species, Chlamydophila psittaci and Chlamydophila abortus, are recognized as causes of zoonotic infections in humans worldwide, mainly affecting persons exposed to infected psittacine and other birds, especially ducks, turkeys, and pigeons, and less commonly to animals, particularly sheep. Outbreaks occur amongst aviary workers, poultry processing workers, and veterinarians. Infection is transmitted through inhalation of infected aerosols contaminated by avian droppings, nasal discharges, or products of ovine gestation or abortion. Person to person transmission is rare. Control strategies have met with variable success depending on the degree of compliance or enforcement of legislation. In the United Kingdom control is secondary, resulting from protection of national poultry flocks by preventing the importation of Newcastle disease virus using quarantine measures. Improved standards of husbandry, transport conditions, and chemoprophylaxis are useful for controlling reactivation of latent avian chlamydial infection. Vaccination has had limited effect in controlling ovine infection. Improved education of persons in occupational risk groups and the requirement for notification may encourage a more energetic approach to its control.

scholarly journals The small molecule H89 inhibits Chlamydia inclusion growth and production of infectious progeny

2021 ◽  
Author(s):  
Karissa J. Muñoz ◽  
Kevin Wang ◽  
Lauren M. Sheehan ◽  
Ming Tan ◽  
Christine Sütterlin
Keyword(s):  
Protein Kinases ◽  
Small Molecule ◽  
Specific Protein ◽  
Human Infection ◽  
Developmental Cycle ◽  
Growth State ◽  
Reticulate Body ◽  
Fold Reduction ◽  
Membrane Bound ◽  
Infectious Form

Chlamydia is an obligate intracellular bacterium and the most common reportable cause of human infection in the U.S. This pathogen proliferates inside a eukaryotic host cell, where it resides within a membrane-bound compartment called the chlamydial inclusion. It has an unusual developmental cycle, marked by conversion between a replicating form, the reticulate body (RB), and an infectious form, the elementary body (EB). We found that the small molecule H89 slowed inclusion growth and decreased overall RB replication by 2-fold, but caused a 25-fold reduction in infectious EBs. This disproportionate effect on EB production was mainly due to a defect in RB-to-EB conversion and not to the induction of chlamydial persistence, which is an altered growth state. Although H89 is a known inhibitor of specific protein kinases and vesicular transport to and from the Golgi, it did not cause these anti-chlamydial effects by blocking the protein kinases PKA or PKC, or by inhibiting protein or lipid transport. H89 is thus a novel anti-chlamydial compound that has a unique combination of effects on the intracellular Chlamydia infection.

scholarly journals A central role of glutamine in Chlamydia infection

2019 ◽  
Author(s):  
Karthika Rajeeve ◽  
Nadine Vollmuth ◽  
Sudha Janaki-Raman ◽  
Thomas Wulff ◽  
Maximilian Schmalhofer ◽  
...  
Keyword(s):  
Host Cell ◽  
Metabolic Reprogramming ◽  
Glutamine Metabolism ◽  
Chlamydia Infection ◽  
Developmental Cycle ◽  
Dependent Manner ◽  
Obligate Intracellular ◽  
A Cell ◽  
Obligate Intracellular Bacteria

AbstractObligate intracellular bacteria like Chlamydia trachomatis undergo a complex developmental cycle between infectious non-replicative (EBs) and non-infectious replicative (RBs) forms. EBs shortly after entering a host cell transform to RBs, a crucial process in infection, initiating chlamydial replication. As Chlamydia fail to replicate outside the host cell it is currently unknown how the transition from EBs to RBs is initiated. Here we show in a cell-free approach in axenic media that uptake of glutamine by the bacteria is critical to initiate EB-RB transition. These bacteria utilize glutamine to synthesize cell wall peptidoglycan which has recently been detected in the septa of replicating intracellular Chlamydia. The increased requirement for glutamine in infected cells is achieved by reprogramming the glutamine metabolism in a c-Myc-dependent manner. Glutamine was effectively taken up by the glutamine transporter SLC1A5 and metabolized via glutaminase. Interference with this metabolic reprogramming limited growth of Chlamydia. Intriguingly, Chlamydia failed to produce progeny in SLC1A5 knockout mice. Thus, we report on the central role of glutamine for the development of an obligate intracellular pathogenic bacterium and the reprogramming of host glutamine metabolism, which may provide a basis for innovative anti-infective strategies.

scholarly journals A Coming of Age Story: Chlamydia in the Post-Genetic Era

2015 ◽  
Vol 84 (3) ◽  
pp. 612-621 ◽  
Author(s):  
Anna J. Hooppaw ◽  
Derek J. Fisher
Keyword(s):  
Global Economy ◽  
Financial Burden ◽  
Developmental Cycle ◽  
Intracellular Bacteria ◽  
Content Type ◽  
Sexually Transmitted ◽  
Obligate Intracellular ◽  
Reticulate Body ◽  
Technological Advances ◽  
Obligate Intracellular Bacteria

Chlamydiaspp. are ubiquitous, obligate, intracellular Gram-negative bacterial pathogens that undergo a unique biphasic developmental cycle transitioning between the infectious, extracellular elementary body and the replicative, intracellular reticulate body. The primaryChlamydiaspecies associated with human disease areC. trachomatis, which is the leading cause of both reportable bacterial sexually transmitted infections and preventable blindness, andC. pneumoniae, which infects the respiratory tract and is associated with cardiovascular disease. Collectively, these pathogens are a significant source of morbidity and pose a substantial financial burden on the global economy. Past efforts to elucidate virulence mechanisms of these unique and important pathogens were largely hindered by an absence of genetic methods. Watershed studies in 2011 and 2012 demonstrated that forward and reverse genetic approaches were feasible withChlamydiaand that shuttle vectors could be selected and maintained within the bacterium. While these breakthroughs have led to a steady expansion of the chlamydial genetic tool kit, there are still roads left to be traveled. This minireview provides a synopsis of the currently available genetic methods forChlamydiaalong with a comparison to the methods used in other obligate intracellular bacteria. Limitations and advantages of these techniques will be discussed with an eye toward the methods still needed, and how the current state of the art for genetics in obligate intracellular bacteria could direct future technological advances forChlamydia.

Enhancing the power generation of Rhodopseudomonas palustris-based MFC

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1261-1268
Author(s):  
Shu Otani ◽  
Dang-Trang Nguyen ◽  
Kozo Taguchi
Keyword(s):  
Activated Carbon ◽  
Rhodopseudomonas Palustris ◽  
Ozone Treatment ◽  
Maximum Power Density ◽  
On Demand ◽  
Long Time ◽  
Dry Conditions ◽  
Carbon Sheet ◽  
Uv Ozone

In this study, a portable and disposable paper-based microbial fuel cell (MFC) was fabricated. The MFC was powered by Rhodopseudomonas palustris bacteria (R. palustris). An activated carbon sheet-based anode pre-loaded organic matter (starch) and R. palustris was used. By using starch in the anode, R. palustris-loaded on the anode could be preserved for a long time in dry conditions. The MFC could generate electricity on-demand activated by adding water to the anode. The activated carbon sheet anode was treated by UV-ozone treatment to remove impurities and to improve its hydrophilicity before being loaded with R. palustris. The developed MFC could generate the maximum power density of 0.9 μW/cm2 and could be preserved for long-term usage with little performance degradation (10% after four weeks).

Charlemagne’s Health in ‘Old Age’: Did It Affect Carolingian Military Strategy?

Mediaevistik ◽  
2020 ◽  
Vol 32 (1) ◽  
pp. 11-53
Author(s):  
Bernard S. Bachrach
Keyword(s):  
Old Age ◽  
The Political ◽  
Military Strategy ◽  
The West ◽  
Long Time

During the first thirty-three years of his reign as king of the Franks, i.e., prior to his coronation as emperor on Christmas day 800, Charlemagne, scholars generally agree, pursued a successful long-term offensive and expansionist strategy. This strategy was aimed at conquering large swaths of erstwhile imperial territory in the west and bringing under Carolingian rule a wide variety of peoples, who either themselves or their regional predecessors previously had not been subject to Frankish regnum.1 For a very long time, scholars took the position that Charlemagne continued to pursue this expansionist strategy throughout the imperial years, i.e., from his coronation on Christmas Day 800 until his final illness in later January 814. For example, Louis Halphen observed: “comme empereur, Charles poursuit, sans plus, l’oeuvre entamée avant l’an 800.”2 F. L. Ganshof, who also wrote several studies treating Charlemagne’s army, was in lock step with Halphen and observed: “As emperor, Charlemagne pursued the political and military course he had been following before 25 December 800.”3

The Spread of Pollutants from Harbour Sludge Depots

1984 ◽  
Vol 16 (3-4) ◽  
pp. 623-633
Author(s):  
M Loxham ◽  
F Weststrate
Keyword(s):  
Time Scales ◽  
Molecular Diffusion ◽  
Near Field ◽  
Parameter Analysis ◽  
Migration Patterns ◽  
Long Time ◽  
Dilution Effects ◽  
Short Time ◽  
Harbour Sludge

It is generally agreed that both the landfill option, or the civil techniques option for the final disposal of contaminated harbour sludge involves the isolation of the sludge from the environment. For short time scales, engineered barriers such as a bentonite screen, plastic sheets, pumping strategies etc. can be used. However for long time scales the effectiveness of such measures cannot be counted upon. It is thus necessary to be able to predict the long term environmenttal spread of contaminants from a mature landfill. A model is presented that considers diffusion and adsorption in the landfill site and convection and adsorption in the underlaying aquifer. From a parameter analysis starting form practical values it is shown that the adsorption behaviour and the molecular diffusion coefficient of the sludge, are the key parameters involved in the near field. The dilution effects of the far field migration patterns are also illustrated.

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