scholarly journals Chlamydiae from Down Under: The Curious Cases of Chlamydial Infections in Australia

2019 ◽  
Vol 7 (12) ◽  
pp. 602
Author(s):  
Martina Jelocnik
Keyword(s):  
Chlamydia Pneumoniae ◽  
Research Field ◽  
Chlamydia Psittaci ◽  
Indigenous Populations ◽  
Future Directions ◽  
Sexually Transmitted ◽  
Chlamydial Species ◽  
Chlamydia Pecorum ◽  
Animal Pathogens ◽  
Human Infections

In Australia, the most researched and perhaps the most successful chlamydial species are the human pathogen Chlamydia trachomatis, animal pathogens Chlamydia pecorum and Chlamydia psittaci. C. trachomatis remains the leading cause of sexually transmitted infections in Australians and trachoma in Australian Indigenous populations. C. pecorum is globally recognised as the infamous koala and widespread livestock pathogen, whilst the avian C. psittaci is emerging as a horse pathogen posing zoonotic risks to humans. Certainly not innocuous, the human infections with Chlamydia pneumoniae seem to be less prevalent that other human chlamydial pathogens (namely C. trachomatis). Interestingly, the complete host range for C. pecorum and C. psittaci remains unknown, and infections by other chlamydial organisms in Australian domesticated and wildlife animals are understudied. Considering that chlamydial organisms can be encountered by either host at the human/animal interface, I review the most recent findings of chlamydial organisms infecting Australians, domesticated animals and native wildlife. Furthermore, I also provide commentary from leading Australian Chlamydia experts on challenges and future directions in the Chlamydia research field.

scholarly journals Chlamydiaceae: Diseases in Primary Hosts and Zoonosis

2019 ◽  
Vol 7 (5) ◽  
pp. 146 ◽  
Author(s):  
Heng Choon Cheong ◽  
Chalystha Yie Qin Lee ◽  
Yi Ying Cheok ◽  
Grace Min Yi Tan ◽  
Chung Yeng Looi ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Sexually Transmitted Diseases ◽  
Community Acquired Pneumonia ◽  
Gram Negative ◽  
Sexually Transmitted ◽  
Obligate Intracellular ◽  
Current Review ◽  
Chlamydial Species ◽  
Mucosal Surfaces ◽  
Animal Pathogens

Bacteria of the Chlamydiaceae family are a type of Gram-negative microorganism typified by their obligate intracellular lifestyle. The majority of the members in the Chlamydiaceae family are known pathogenic organisms that primarily infect the host mucosal surfaces in both humans and animals. For instance, Chlamydia trachomatis is a well-known etiological agent for ocular and genital sexually transmitted diseases, while C. pneumoniae has been implicated in community-acquired pneumonia in humans. Other chlamydial species such as C. abortus, C. caviae, C. felis, C. muridarum, C. pecorum, and C. psittaci are important pathogens that are associated with high morbidities in animals. Importantly, some of these animal pathogens have been recognized as zoonotic agents that pose a significant infectious threat to human health through cross-over transmission. The current review provides a succinct recapitulation of the characteristics as well as transmission for the previously established members of the Chlamydiaceae family and a number of other recently described chlamydial organisms.

scholarly journals Production of a Proteolytically Active Protein, Chlamydial Protease/Proteasome-Like Activity Factor, by Five Different Chlamydia Species

2005 ◽  
Vol 73 (3) ◽  
pp. 1868-1872 ◽  
Author(s):  
Feng Dong ◽  
Youmin Zhong ◽  
Bernard Arulanandam ◽  
Guangming Zhong
Keyword(s):  
Transcription Factors ◽  
Chlamydia Trachomatis ◽  
Chlamydia Pneumoniae ◽  
Chlamydia Psittaci ◽  
Active Protein ◽  
Chlamydia Muridarum ◽  
Chlamydial Species ◽  
Activity Factor ◽  
In Cells

ABSTRACT We have previously identified a chlamydial protein, chlamydial protease/proteasome-like activity factor (CPAF), for degrading host transcription factors in cells infected with the human chlamydial species Chlamydia trachomatis or Chlamydia pneumoniae. We now report that functional CPAF was also produced during infection with the species Chlamydia muridarum, Chlamydia psittaci, and Chlamydia caviae, which primarily infect nonhuman hosts.

scholarly journals Оновлення таксономічної класифікації мікроорганізмів порядку Chlamydiales

2019 ◽  
pp. 207-215 ◽  
Author(s):  
В. К. Зезекало ◽  
С. Б. Передера ◽  
Н.С. Щербакова
Keyword(s):  
Chlamydia Trachomatis ◽  
Research Methods ◽  
Chlamydia Pneumoniae ◽  
Chlamydia Psittaci ◽  
Taxonomic Classification ◽  
Chlamydia Muridarum ◽  
Detailed Explanation ◽  
Chlamydia Pecorum ◽  
Chlamydia Suis

Мета статті – надати актуальну на сьогоднішній день таксономічну класифікацію порядку Chlamydiales та детально роз’яснити терміни: «Chlamydia-related bacteria (CRB)» (хламідіє-споріднені бактерії,) «Chlamydia-like organisms (CLO)» (хламідіє-подібні організми), «environmental chlamydiae» (екологічні хламідії, хламідії довкілля). Методика дослідження. Використано такі методи дослідження: системний аналіз доступних наукових джерел, історичний метод (для вивчення виникнення, формування та розвитку таксономії хламідійних видів у хронологічній послідовності), емпіричний метод (щодо комплексної оцінки сучасного стану об’єкта дослідження), абстрактно-логічний ‒ для уточнення суті основних понять та графічне відображення даних. Результати дослідження. Внаслідок розвитку молекулярної біології за останні 15 років класифікація хламідій зазнала істотних змін і має тенденцію до подальшого вдосконалення. У статті  узагальнено історичний досвід і найбільш важливі зміни в таксономії порядку Chlamydiales за останні роки. Ускладнення сучасної класифікації бактерій порядку Chlamydiales свідчить про накопичені знання щодо нових представників цієї групи мікроорганізмів. На сьогодні до порядку Chlamydiales входять 9 родин: Chlamydiaceae, Waddliaceae, Parachlamydiaceae, Criblamydiaceae, Simkaniaceae, Candidatus Clavochlamydiaceae, Candidatus Rhabdochlamydiaceae, Candidatus Piscichlamydia, Candidatus Parilichlamydiaceae, чотири з яких перебувають у статусі кандидатів. До родини Chlamydiaceae, роду Chlamydia тепер належать 14 видів бактерій (Chlamydia abortus, Chlamydia avium, Chlamydia caviae, Chlamydia felis, Chlamydia gallinacea, Chlamydia muridarum, Chlamydia pecorum, Chlamydia pneumoniae, Chlamydia psittaci, Chlamydia suis, Chlamydia trachomatis, Candidatus Chlamydia ibidis, Candidatus Chlamydia sanzinia, Candidatus Chlamydia corallus), три з яких перебувають у статусі кандидатів. Родини: Waddliaceae, Parachlamydiaceae, Criblamydiaceae, Simkaniaceae, Ca. Clavochlamydiaceae, Ca. Rhabdochlamydiaceae, Ca. Piscichlamydia, Ca. Parilichlamydiaceae з їхніми численними представниками називають хламідіє-спорідненими бактеріями, або хламідіє-подібними організмами, через їх генетичну і фенотипову подібність та філогенетичну відокремленість від родини Chlamydiaceae. Елементи наукової новизни. У цій статті представлено актуальну  таксономічну класифікацію порядку Chlamydiales та надано детально роз’яснено терміни: «Chlamydia-related bacteria (CRB)» (хламідіє-спорідненені бактерії,) «Chlamydia-like organisms (CLO)» (хламідіє-подібні організми), «environmental chlamydiae» (екологічні хламідії, хламідії довкілля). Практична значущість. Надана інформація може бути використана в наукових дослідженнях, впроваджена в навчальний процес при підготовці спеціалістів у галузі ветеринарної медицини, а також використовуватися практикуючими лікарями ветеринарної медицини задля покращення лікування та профілактики хламідіозів тварин та людини. The purpose of the article is to provide the currently relevant taxonomic classification of the Order Chlamydiales, and give a detailed explanation of the terms: “Chlamydia-related bacteria (CRB)”, “Chlamydia-like organisms (CLO)”, "Environmental chlamydiae" (ecological chlamidiae). Research methods. The following research methods were used: system analysis of the available scientific sources, historical method (to study the origin, formation and development of the taxonomy of chlamydia species in chronological order), empirical method (concerning the comlex assessment of the current state of the research object), abstract-logical – to clarify the essence of the basic notions and graphical reflection of the data. The results of the study. As a result of   molecular biology development during the recent 15 years, the classification of chlamydia has undergone significant changes and has the tendency to further improvement. This review article is aimed at summarizing the historical experience and the most important changes in the taxonomy of the Order Chlamydiales in recent years. The complication of the modern classification of the Order Chlamydiales bacteria is the inevitable consequence of accumulating knowledge about the new representatives of this group of microorganisms. Consequently at present there are 9 families in the Order Chlamydiales: Chlamydiaceae, Waddliaceae, Parachlamydiaceae, Criblamydiaceae, Simkaniaceae, Candidatus Clavochlamydiaceae, Candidatus Rhabdochlamydiaceae, Candidatus Piscichlamydia, Candidatus Parilichlamydiaceae, four of them are in the status of candidates. Currently, 14 species of bacteria belong to the family Chlamydiaceae, the genus Chlamydia (Chlamydia abortus, Chlamydia avium, Chlamydia caviae, Chlamydia felis, Chlamydia gallinacea, Chlamydia muridarum, Chlamydia pecorum, Chlamydia pneumoniae, Chlamydia psittaci, Chlamydia suis, Chlamydia trachomatis, Candidatus Chlamydia ibidis, Candidatus Chlamydia sanzinia, Candidatus Chlamydia corallus), three of which are the candidates. Such families as: Waddliaceae, Parachlamydiaceae, Criblamydiaceae, Simkaniaceae, Ca. Clavochlamydiaceae, Ca. Rhabdochlamydiaceae, Ca. Piscichlamydia, Ca. Parilichlamydiaceae with their numerous representatives are called Сhlamydia-related bacteria, or Сhlamydia-like organisms, due to their genetic and phenotypic similarity, and phylogenetic isolation from the Chlamydiaceae family. The elements of scientific novelty. The currently relevant taxonomic classification of Chlamydiales is presented in the article and also given a detailed explanation of the terms: “Chlamydia-related bacteria (CRB)”, “Chlamydia-like organisms (CLO)”, "Environmental chlamydiae". Practical significance. The provided information can be used in scientific research, introduced into the educational process for training specialists of veterinary medicine, and also be used by practicing veterinary doctors in order to improve the treatment and prevention of animals and human chlamydioses.

Molecular mimicry and horror autotoxicus: do chlamydial infections elicit autoimmunity?

2006 ◽  
Vol 8 (29) ◽  
pp. 1-23 ◽  
Author(s):  
Robert H. Swanborg ◽  
Dov L. Boros ◽  
Judith A. Whittum-Hudson ◽  
Alan P. Hudson
Keyword(s):  
Chlamydial Infection ◽  
Chlamydia Pneumoniae ◽  
Molecular Mimicry ◽  
Community Acquired Pneumonia ◽  
Respiratory Pathogen ◽  
Human Pathogens ◽  
Sexually Transmitted ◽  
Obligate Intracellular ◽  
Chlamydial Species ◽  
Preventable Blindness

All species of the order Chlamydiales are obligate intracellular eubacterial pathogens of their various hosts. Two chlamydial species, Chlamydia trachomatis and Chlamydia pneumoniae, are primarily human pathogens, and each is known to cause important diseases. Some strains of C. trachomatis are sexually transmitted and frequently cause severe reproductive problems, primarily in women. Other strains of the organism serve as the aetiological agents for blinding trachoma, still the leading cause of preventable blindness in underdeveloped nations. C. pneumoniae is a respiratory pathogen known to cause community-acquired pneumonia. Importantly, both organisms engender an immunopathogenic response in the human host, and both have been associated with widely diverse, relatively common and currently idiopathic chronic diseases, most of which include an important autoimmune component. In this article, we explore the available experimental data regarding the possible elicitation of autoimmunity in various contexts by chlamydial infection, and we suggest several avenues for research to explore this potentially important issue further.

Specificity of the microimmunofluorescence assay for the serodiagnosis of Chlamydia pneumoniae infections

1992 ◽  
Vol 38 (11) ◽  
pp. 1185-1189 ◽  
Author(s):  
Gérard Ozanne ◽  
Johanne Lefebvre
Keyword(s):  
Chlamydia Trachomatis ◽  
Key Words ◽  
Chlamydia Pneumoniae ◽  
Species Specificity ◽  
Chlamydia Psittaci ◽  
Serological Evidence ◽  
Recent Infection ◽  
Cross Reactions ◽  
Chlamydial Species ◽  
Microimmunofluorescence Test

Chlamydia pneumoniae infections are mostly confirmed using an indirect microimmunofluorescence test for which potential cross-reactions between antigens from different chlamydial species are not well documented. Using this assay, 928 sera (507 subjects) submitted for Chlamydia pneumoniae serology were tested for specific IgM and IgG to this bacteria using the TW-183 antigen. IgM and IgG reactivities to Chlamydia trachomatis serotypes C, D, E, and L2 and Chlamydia psittaci strain 6BC antigens were also tested. A sample was interpreted as positive only when evenly fluorescent elementary bodies were observed. Twenty-five subjects (4.9%) showed serological evidence of recent Chlamydia pneumoniae infection (IgM positive and (or) IgG seroconversion); 11 of them also showed serological evidence of recent infection with at least one other chlamydial species. Specificity was 50 and 63% for IgM and IgG detection, respectively. These results suggest that mixed or temporally related infections might occur, or, more likely, that some Chlamydia pneumoniae IgM or IgG reactivities might be due to heterotypic antibodies. Key words: TWAR serology, TWAR infections, TWAR cross-reactions.

Green Synthesized Nanomaterials as Theranostic Platforms for Cancer Treatment: Principles, Challenges and the Road Ahead

2019 ◽  
Vol 26 (8) ◽  
pp. 1311-1327 ◽  
Author(s):  
Pala Rajasekharreddy ◽  
Chao Huang ◽  
Siddhardha Busi ◽  
Jobina Rajkumari ◽  
Ming-Hong Tai ◽  
...  
Keyword(s):  
Nanoparticle Synthesis ◽  
Research Field ◽  
Synthesis Methods ◽  
Synthetic Approach ◽  
Future Directions ◽  
The Road ◽  
New Methods ◽  
Recent Developments ◽  
Theranostic Applications ◽  
Insight Into

With the emergence of nanotechnology, new methods have been developed for engineering various nanoparticles for biomedical applications. Nanotheranostics is a burgeoning research field with tremendous prospects for the improvement of diagnosis and treatment of various cancers. However, the development of biocompatible and efficient drug/gene delivery theranostic systems still remains a challenge. Green synthetic approach of nanoparticles with low capital and operating expenses, reduced environmental pollution and better biocompatibility and stability is a latest and novel field, which is advantageous over chemical or physical nanoparticle synthesis methods. In this article, we summarize the recent research progresses related to green synthesized nanoparticles for cancer theranostic applications, and we also conclude with a look at the current challenges and insight into the future directions based on recent developments in these areas.

A Survey on Document-level Neural Machine Translation

2021 ◽  
Vol 54 (2) ◽  
pp. 1-36
Author(s):  
Sameen Maruf ◽  
Fahimeh Saleh ◽  
Gholamreza Haffari
Keyword(s):  
Machine Translation ◽  
Language Processing ◽  
Research Field ◽  
Translation Process ◽  
Future Directions ◽  
Translation Quality ◽  
Current State ◽  
Evaluation Strategies ◽  
Almost All ◽  
Document Level

Machine translation (MT) is an important task in natural language processing (NLP), as it automates the translation process and reduces the reliance on human translators. With the resurgence of neural networks, the translation quality surpasses that of the translations obtained using statistical techniques for most language-pairs. Up until a few years ago, almost all of the neural translation models translated sentences independently , without incorporating the wider document-context and inter-dependencies among the sentences. The aim of this survey article is to highlight the major works that have been undertaken in the space of document-level machine translation after the neural revolution, so researchers can recognize the current state and future directions of this field. We provide an organization of the literature based on novelties in modelling and architectures as well as training and decoding strategies. In addition, we cover evaluation strategies that have been introduced to account for the improvements in document MT, including automatic metrics and discourse-targeted test sets. We conclude by presenting possible avenues for future exploration in this research field.

scholarly journals The role of airborne volcanic ash for the surface ocean biogeochemical iron-cycle: a review

2009 ◽  
Vol 6 (4) ◽  
pp. 6441-6489 ◽  
Author(s):  
S. Duggen ◽  
N. Olgun ◽  
P. Croot ◽  
L. Hoffmann ◽  
H. Dietze ◽  
...  
Keyword(s):  
Large Scale ◽  
Volcanic Ash ◽  
Volcanic Eruptions ◽  
Research Field ◽  
Ash Deposition ◽  
Future Directions ◽  
Iron Cycle ◽  
Surface Ocean ◽  
Wide Range

Abstract. Iron is a key micronutrient for phytoplankton growth in the surface ocean. Yet the significance of volcanism for the marine biogeochemical iron-cycle is poorly constrained. Recent studies, however, suggest that offshore deposition of airborne ash from volcanic eruptions is a way to inject significant amounts of bio-available iron into the surface ocean. Volcanic ash may be transported up to several tens of kilometres high into the atmosphere during large-scale eruptions and fine ash may encircle the globe for years, thereby reaching even the remotest and most iron-starved oceanic areas. Scientific ocean drilling demonstrates that volcanic ash layers and dispersed ash particles are frequently found in marine sediments and that therefore volcanic ash deposition and iron-injection into the oceans took place throughout much of the Earth's history. The data from geochemical and biological experiments, natural evidence and satellite techniques now available suggest that volcanic ash is a so far underestimated source for iron in the surface ocean, possibly of similar importance as aeolian dust. Here we summarise the development of and the knowledge in this fairly young research field. The paper covers a wide range of chemical and biological issues and we make recommendations for future directions in these areas. The review paper may thus be helpful to improve our understanding of the role of volcanic ash for the marine biogeochemical iron-cycle, marine primary productivity and the ocean-atmosphere exchange of CO2 and other gases relevant for climate throughout the Earth's history.

scholarly journals Novel Genital Alphapapillomaviruses in Baboons (Papio hamadryas Anubis) With Cervical Dysplasia

2012 ◽  
Vol 50 (1) ◽  
pp. 200-208 ◽  
Author(s):  
I. L. Bergin ◽  
J. D. Bell ◽  
Z. Chen ◽  
M. K. Zochowski ◽  
D. Chai ◽  
...  
Keyword(s):  
Cervical Dysplasia ◽  
Intraepithelial Neoplasia ◽  
Papio Hamadryas ◽  
Primate Species ◽  
Low Grade ◽  
Sexually Transmitted ◽  
Olive Baboons ◽  
Papio Hamadryas Anubis ◽  
Squamous Intraepithelial Neoplasia ◽  
Human Infections

Genital Alphapapillomavirus (αPV) infections are one of the most common sexually transmitted human infections worldwide. Women infected with the highly oncogenic genital human papillomavirus (HPV) types 16 and 18 are at high risk for development of cervical cancer. Related oncogenic αPVs exist in rhesus and cynomolgus macaques. Here the authors identified 3 novel genital αPV types (PhPV1, PhPV2, PhPV3) by PCR in cervical samples from 6 of 15 (40%) wild-caught female Kenyan olive baboons ( Papio hamadryas anubis). Eleven baboons had koilocytes in the cervix and vagina. Three baboons had dysplastic proliferative changes consistent with cervical squamous intraepithelial neoplasia (CIN). In 2 baboons with PCR-confirmed PhPV1, 1 had moderate (CIN2, n = 1) and 1 had low-grade (CIN1, n = 1) dysplasia. In 2 baboons with PCR-confirmed PhPV2, 1 had low-grade (CIN1, n = 1) dysplasia and the other had only koilocytes. Two baboons with PCR-confirmed PhPV3 had koilocytes only. PhPV1 and PhPV2 were closely related to oncogenic macaque and human αPVs. These findings suggest that αPV-infected baboons may be useful animal models for the pathogenesis, treatment, and prophylaxis of genital αPV neoplasia. Additionally, this discovery suggests that genital αPVs with oncogenic potential may infect a wider spectrum of non-human primate species than previously thought.

scholarly journals Comparative Analysis of Chlamydia psittaci Genomes Reveals the Recent Emergence of a Pathogenic Lineage with a Broad Host Range

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Timothy D. Read ◽  
Sandeep J. Joseph ◽  
Xavier Didelot ◽  
Brooke Liang ◽  
Lisa Patel ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
New World ◽  
Evolutionary Dynamics ◽  
Chlamydia Psittaci ◽  
South American ◽  
Content Type ◽  
Sexually Transmitted ◽  
Genome Wide ◽  
Life Threatening ◽  
History Of

ABSTRACT Chlamydia psittaci is an obligate intracellular bacterium. Interest in Chlamydia stems from its high degree of virulence as an intestinal and pulmonary pathogen across a broad range of animals, including humans. C. psittaci human pulmonary infections, referred to as psittacosis, can be life-threatening, which is why the organism was developed as a bioweapon in the 20th century and is listed as a CDC biothreat agent. One remarkable recent result from comparative genomics is the finding of frequent homologous recombination across the genome of the sexually transmitted and trachoma pathogen Chlamydia trachomatis. We sought to determine if similar evolutionary dynamics occurred in C. psittaci. We analyzed 20 C. psittaci genomes from diverse strains representing the nine known serotypes of the organism as well as infections in a range of birds and mammals, including humans. Genome annotation revealed a core genome in all strains of 911 genes. Our analyses showed that C. psittaci has a history of frequently switching hosts and undergoing recombination more often than C. trachomatis. Evolutionary history reconstructions showed genome-wide homologous recombination and evidence of whole-plasmid exchange. Tracking the origins of recombinant segments revealed that some strains have imported DNA from as-yet-unsampled or -unsequenced C. psittaci lineages or other Chlamydiaceae species. Three ancestral populations of C. psittaci were predicted, explaining the current population structure. Molecular clock analysis found that certain strains are part of a clonal epidemic expansion likely introduced into North America by South American bird traders, suggesting that psittacosis is a recently emerged disease originating in New World parrots. IMPORTANCE Chlamydia psittaci is classified as a CDC biothreat agent based on its association with life-threatening lung disease, termed psittacosis, in humans. Because of the recent remarkable findings of frequent recombination across the genome of the human sexually transmitted and ocular trachoma pathogen Chlamydia trachomatis, we sought to determine if similar evolutionary dynamics occur in C. psittaci. Twenty C. psittaci genomes were analyzed from diverse strains that may play a pathogenic role in human disease. Evolution of the strains revealed genome-wide recombination occurring at a higher rate than for C. trachomatis. Certain strains were discovered to be part of a recent epidemic clonal expansion originating in South America. These strains may have been introduced into the United States from South American bird traders, suggesting that psittacosis is a recently emerged disease originating in New World parrots. Our analyses indicate that C. psittaci strains have a history of frequently switching hosts and undergoing recombination.

Sign in / Sign up

Export Citation Format

Share Document