scholarly journals Chlamydia trachomatis YtgA is an iron-binding periplasmic protein induced by iron restriction

Microbiology ◽  
2009 ◽  
Vol 155 (9) ◽  
pp. 2884-2894 ◽  
Author(s):  
J. D. Miller ◽  
M. S. Sal ◽  
M. Schell ◽  
J. D. Whittimore ◽  
J. E. Raulston
Keyword(s):  
Chlamydia Trachomatis ◽  
Iron Acquisition ◽  
Periplasmic Protein ◽  
Iron Starvation ◽  
Sexually Transmitted ◽  
Iron Restriction ◽  
Abc Transport ◽  
Transmission Electron ◽  
Biochemical Assays

Chlamydia trachomatis is a Gram-negative obligate intracellular bacterium that is the causative agent of common sexually transmitted diseases and the leading cause of preventable blindness worldwide. It has been observed that YtgA (CT067) is very immunogenic in patients with chlamydial genital infections. Homology analyses suggested that YtgA is a soluble periplasmic protein and a component of an ATP-binding cassette (ABC) transport system for metals such as iron. Since little is known about iron transport in C. trachomatis, biochemical assays were used to determine the potential role of YtgA in iron acquisition. 59Fe binding and competition studies revealed that YtgA preferentially binds iron over nickel, zinc or manganese. Western blot and densitometry techniques showed that YtgA concentrations specifically increased 3–5-fold in C. trachomatis, when cultured under iron-starvation conditions rather than under general stress conditions, such as exposure to penicillin. Finally, immuno-transmission electron microscopy provided evidence that YtgA is more concentrated in C. trachomatis during iron restriction, supporting a possible role for YtgA as a component of an ABC transporter.

scholarly journals Chlamydia trachomatis and urogenital mycoplasms in nonconococcal urethirits in men

2010 ◽  
Vol 63 (1-2) ◽  
pp. 47-50
Author(s):  
Sonja Vesic ◽  
Jelica Vukicevic ◽  
Eleonora Gvozdenovic ◽  
Dusan Skiljevic ◽  
Slobodanka Janosevic ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Ureaplasma Urealyticum ◽  
Mycoplasma Hominis ◽  
Sexually Active ◽  
Transmitted Infection ◽  
Sexually Transmitted ◽  
Nongonococcal Urethritis ◽  
Etiological Agents ◽  
The One

Introduction. Nongonococcal urethritis is the most common sexually transmitted infection in men, with vast majority of the etiological agents such as Chlamydia trachomatis, followed by urogenital mycoplasmas. The aim of this study was to determine the prevalence of Chlamydia trachomatis, Ureaplasma urealyticum and Mycoplasma hominis in nongonococcal urethritis in men, and to examine infections associated with these agents. Material and methods. 299 sexually active, heterosexual men with nongonococcal urethritis were included into the study. Urethral samples were taken with a dacron swab placed into the urethra up to 2-3 cm. The Direct immunojluorescence tehnique was performed for identification of Chlamydia trachomatis. Ureaplasma urealyticum and Mycoplasma hominis were detected with Mycoplasma 1ST assay. Results. Chlamydia trachomatis was detected in 22.75%, Uraeplasma urealyticum in 21.08% and Mycoplasma hominis in 8.02% cases. We found no significant differences in prevalence between Chlamydia trachomatis and Ureaplasma urealyticym (p>0.05). Monoinjections were found in 51.85% with significantly higher rate (p<0.01) than associated infections (11.70%). Among associated infections, coinfection of Chlamydia trahomatis and Ureaplasma urealyticum was predominant. Association of Chlamydia trachomatis with urogenital mycoplasmas was significantly higher (p<0.05) than the one between Ureaplasma urealyticum and Mycoplasma hominis. In 36.45% patients no patogenic microorganisms were detected. Conclusion. These results confirmed the etiological role of Chlamydia trachomatis and urogenital mycoplasmas in nongonococcal urethritis with prevalence of 51.85% in monoinfections and 11.70% in associated infections. In 36.45% of cases the etiology of urethritis was not elucidated. These results suggest that more sensitive diagnostic tool should be applied when searching for the detailed etiology of nongonococcal urethritis.

scholarly journals Chlamydia trachomatis infection: a challenge for the urologist

2011 ◽  
Vol 2 (1) ◽  
pp. 14 ◽  
Author(s):  
Tommaso Cai ◽  
Sandra Mazzoli ◽  
Nicola Mondaini ◽  
Gianni Malossini ◽  
Riccardo Bartoletti
Keyword(s):  
Chlamydia Trachomatis ◽  
Bacterial Infections ◽  
Reproductive Tract ◽  
Diagnosis And Treatment ◽  
Everyday Clinical Practice ◽  
Chlamydia Trachomatis Infection ◽  
Sexually Transmitted ◽  
New Findings ◽  
Asymptomatic Infections

<p>The role of <em>Chlamydia trachomatis</em> (Ct) in everyday clinical practice is now on the increase because Ct infections are the most prevalent sexually transmitted bacterial infections worldwide. Ct can cause urethritis, cervicitis, pharyngitis, or epididymitis, although asymptomatic infections are quite common. Ct infection remains asymptomatic in approximately 50% of infected men and 70% of infected women, with risk for reproductive tract sequelae both in women and men. A proper early diagnosis and treatment is essential in order to prevent persistent consequences. An accurate comprehension of the pathology, diagnosis and treatment of this entity is essential for the urologist. We review the literature about the new findings in diagnosis and treatment of Ct infection in sexually active young men.</p>

scholarly journals The Transcriptomic and Bioinformatic Characterizations of Iron Acquisition and Heme Utilization in Avibacterium paragallinarum in Response to Iron-Starvation

2021 ◽  
Vol 12 ◽  
Author(s):  
Caiyun Huo ◽  
Ximin Zeng ◽  
Fuzhou Xu ◽  
Fangbing Li ◽  
Donghai Li ◽  
...  
Keyword(s):  
Iron Homeostasis ◽  
Iron Acquisition ◽  
Control Group ◽  
Rna Seq ◽  
Iron Starvation ◽  
Transcriptomic Response ◽  
Iron Restriction ◽  
Infectious Coryza ◽  
Avibacterium Paragallinarum ◽  
Restriction Group

Avibacterium paragallinarum is the pathogen of infectious coryza, which is a highly contagious respiratory disease of chickens that brings a potentially serious threat to poultry husbandry. Iron is an important nutrient for bacteria and can be obtained from surroundings such as siderophores and hemophores. To date, the mechanisms of iron acquisition and heme utilization as well as detailed regulation in A. paragallinarum have been poorly understood. In this study, we investigated the transcriptomic profiles in detail and the changes of transcriptomes induced by iron restriction in A. paragallinarum using RNA-seq. Compared with the iron-sufficiency control group, many more differentially expressed genes (DEGs) and cellular functions as well as signaling pathways were verified in the iron-restriction group. Among these DEGs, the majority of genes showed decreased expression and some were found to be uniquely present in the iron-restriction group. With an in-depth study of bioinformatic analyses, we demonstrated the crucial roles of the Hut protein and DUF domain-containing proteins, which were preferentially activated in bacteria following iron restriction and contributed to the iron acquisition and heme utilization. Consequently, RT-qPCR results further verified the iron-related DEGs and were consistent with the RNA-seq data. In addition, several novel sRNAs were present in A. paragallinarum and had potential regulatory roles in iron homeostasis, especially in the regulation of Fic protein to ensure stable expression. This is the first report of the molecular mechanism of iron acquisition and heme utilization in A. paragallinarum from the perspective of transcriptomic profiles. The study will contribute to a better understanding of the transcriptomic response of A. paragallinarum to iron starvation and also provide novel insight into the development of new antigens for potential vaccines against infectious coryza by focusing on these iron-related genes.

scholarly journals Lactobacillus crispatus BC1 Biosurfactant Counteracts the Infectivity of Chlamydia trachomatis Elementary Bodies

2021 ◽  
Vol 9 (5) ◽  
pp. 975
Author(s):  
Claudio Foschi ◽  
Carola Parolin ◽  
Barbara Giordani ◽  
Sara Morselli ◽  
Barbara Luppi ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Hela Cells ◽  
Myristic Acid ◽  
Contact Time ◽  
Therapeutic Agents ◽  
Inhibitory Effects ◽  
Sexually Transmitted ◽  
Lactobacillus Crispatus ◽  
Novel Therapeutic

Lactobacilli-derived biosurfactants (BS) have shown promising effects as antimicrobial molecules. Since Lactobacillus crispatus plays a crucial role in maintaining vaginal eubiosis, BS from this species could represent novel therapeutic agents to counteract sexually transmitted pathogens, such as Chlamydia trachomatis (CT). The aim of the present study was to assess the inhibitory effects of a BS produced by the vaginal strain L. crispatus BC1 on the infectivity of CT elementary bodies (EBs). For concentrations ranging between 1 and 0.5 mg/mL at 60-min contact time, L. crispatus BC1 BS displayed a highly significant anti-CT activity, with about 50% reduction of EB infectivity towards HeLa cells. To identify the components responsible for chlamydial inhibition, a panel of selected fatty acids, including those present in BS lipopeptidic structure, was tested against CT EBs. Pentadecanoic acid, myristic acid, β-hydroxy-myristic acid, and β-hydroxy-palmitic acid were able to significantly reduce EBs infectivity up to 5–0.5 µg/mL, concentrations that resulted to be non-toxic for HeLa cells. These data can contribute to the understanding of the biological role of lactobacilli in the vaginal niche, as well as to promote the application of their produced BS as an innovative and antibiotic-sparing anti-chlamydial strategy.

scholarly journals Alterations of Vaginal Microbiota in Women With Infertility and Chlamydia trachomatis Infection

2021 ◽  
Vol 11 ◽  
Author(s):  
Hongliang Chen ◽  
Li Wang ◽  
Lanhua Zhao ◽  
Lipei Luo ◽  
Shuling Min ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Female Genital Tract ◽  
Operational Taxonomic Unit ◽  
Vaginal Microbiota ◽  
Rrna Gene ◽  
Tubal Infertility ◽  
Chlamydia Trachomatis Infection ◽  
Sexually Transmitted ◽  
Female Genital

Chlamydia trachomatis (C. trachomatis) is the most common etiological agent of bacterial sexually transmitted infections (STIs) worldwide and causes serious health sequelae such as cervicitis, pelvic inflammatory disease, and even infertility if ascending from the lower to the upper female genital tract. Previous studies have revealed the pivotal role of vaginal microbiota in susceptibility to STIs. However, alterations in the vaginal microbiota in women who are infertile and infected with C. trachomatis remain unknown. This study used metagenomic analysis of sequenced 16S rRNA gene amplicons to examine the vaginal microbial profiles of women with tubal infertility who were C. trachomatis-negative and those who were C. trachomatis-positive pre- and post-antibiotic treatment. Women who were C. trachomatis-negative and deemed healthy were recruited as references of eubiosis and dysbiosis. Women with tubal infertility and C. trachomatis infection presented a unique Lactobacillus iners-dominated vaginal microbiota rather than one dominated by Lactobacillus crispatus and displayed a decrease in Lactobacillus, Bifidobacterium, Enterobacter, Atopobium, and Streptococcus, accompanied by decreased levels of cytokines such as interferon (IFN)-γ and interleukin (IL)-10. This altered vaginal microbiota could be restored with varying degrees after standard treatment for C. trachomatis. This shift could be a predictive vaginal microbiota signature for C. trachomatis infection among females with tubal infertility, while no significant differences in phylum, class, and operational taxonomic unit (OTU) levels were observed between women with tubal infertility who were C. trachomatis-negative and healthy controls. This is the first study to provide data on the association of vaginal microbiota with C. trachomatis infection among women with tubal infertility and highlights unprecedented potential opportunities to predict C. trachomatis infection.

scholarly journals Update on Chlamydia trachomatis Vaccinology

2017 ◽  
Vol 24 (4) ◽  
Author(s):  
Luis M. de la Maza ◽  
Guangming Zhong ◽  
Robert C. Brunham
Keyword(s):  
Chlamydia Trachomatis ◽  
Mouse Model ◽  
Female Mouse ◽  
Disease Exacerbation ◽  
Content Type ◽  
Sexually Transmitted ◽  
Acute Infections ◽  
The 1960S

ABSTRACT Attempts to produce a vaccine to protect against Chlamydia trachomatis-induced trachoma were initiated more than 100 years ago and continued for several decades. Using whole organisms, protective responses were obtained. However, upon exposure to C. trachomatis, disease exacerbation developed in some immunized individuals, precluding the implementation of the vaccine. Evidence of the role of C. trachomatis as a sexually transmitted pathogen started to emerge in the 1960s, and it soon became evident that it can cause acute infections and long-term sequelae in women, men, and newborns. The main focus of this minireview is to summarize recent findings and discuss formulations, including antigens, adjuvants, routes, and delivery systems for immunization, primarily explored in the female mouse model, with the goal of implementing a vaccine against C. trachomatis genital infections.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

Transmission Electron Microscopy studies of texture of Cr underlayer of magnetic recording hard disk

1991 ◽  
Vol 49 ◽  
pp. 580-581
Author(s):  
L. Tang ◽  
G. Thomas ◽  
M. R. Khan ◽  
S. L. Duan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Magnetic Recording ◽  
Magnetic Thin Films ◽  
Magnetic Films ◽  
Substrate Bias ◽  
Epitaxial Relationship ◽  
Transmission Electron

Cr thin films are often used as underlayers for Co alloy magnetic thin films, such as Co1, CoNi2, and CoNiCr3, for high density longitudinal magnetic recording. It is belived that the role of the Cr underlayer is to control the growth and texture of the Co alloy magnetic thin films, and, then, to increase the in plane coercivity of the films. Although many epitaxial relationship between the Cr underlayer and the magnetic films, such as ﹛1010﹜Co/ {110﹜Cr4, ﹛2110﹜Co/ ﹛001﹜Cr5, ﹛0002﹜Co/﹛110﹜Cr6, have been suggested and appear to be related to the Cr thickness, the texture of the Cr underlayer itself is still not understood very well. In this study, the texture of a 2000 Å thick Cr underlayer on Nip/Al substrate for thin films of (Co75Ni25)1-xTix dc-sputtered with - 200 V substrate bias is investigated by electron microscopy.

Transmission Electron Microscopy of Evaporated Perylene Thin Films

1990 ◽  
Vol 48 (2) ◽  
pp. 336-337
Author(s):  
C. Ewins ◽  
J.R. Fryer
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Molecular Electronics ◽  
High Vacuum ◽  
Amorphous Layer ◽  
Electric Heater ◽  
Transmission Electron ◽  
Polycyclic Aromatic

The preparation of thin films of organic molecules is currently receiving much attention because of the need to produce good quality thin films for molecular electronics. We have produced thin films of the polycyclic aromatic, perylene C10H12 by evaporation under high vacuum onto a potassium chloride (KCl) substrate. The role of substrate temperature in determining the morphology and crystallography of the films was then investigated by transmission electron microscopy (TEM).The substrate studied was the (001) face of a freshly cleaved crystal of KCl. The temperature of the KCl was controlled by an electric heater or a cold finger. The KCl was heated to 200°C under a vacuum of 10-6 torr and allowed to cool to the desired temperature. The perylene was then evaporated over a period of one minute from a molybdenum boat at a distance of 10cm from the KCl. The perylene thin film was then backed with an amorphous layer of carbon and floated onto copper microscope grids.

Fine structure and possible functions of the hermaphrodite duct of some pulmonate snails (Mollusca: Gastropoda)

1990 ◽  
Vol 48 (3) ◽  
pp. 68-69
Author(s):  
Alan N. Hodgson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Seminal Vesicle ◽  
Reproductive Biology ◽  
Light Microscope ◽  
Light Microscope Level ◽  
Transmission Electron ◽  
Standard Techniques

The hermaphrodite duct of pulmonate snails connects the ovotestis to the fertilization pouch. The duct is typically divided into three zones; aproximal duct which leaves the ovotestis, the middle duct (seminal vesicle) and the distal ovotestis duct. The seminal vesicle forms the major portion of the duct and is thought to store sperm prior to copulation. In addition the duct may also play a role in sperm maturation and degredation. Although the structure of the seminal vesicle has been described for a number of snails at the light microscope level there appear to be only two descriptions of the ultrastructure of this tissue. Clearly if the role of the hermaphrodite duct in the reproductive biology of pulmonatesis to be understood, knowledge of its fine structure is required.Hermaphrodite ducts, both containing and lacking sperm, of species of the terrestrial pulmonate genera Sphincterochila, Levantina, and Helix and the marine pulmonate genus Siphonaria were prepared for transmission electron microscopy by standard techniques.

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