scholarly journals Aggregatibacter, a Low Abundance Pathobiont That Influences Biogeography, Microbial Dysbiosis, and Host Defense Capabilities in Periodontitis: The History of a Bug, and Localization of Disease

Pathogens ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 179 ◽  
Author(s):  
Daniel H. Fine ◽  
Helen Schreiner ◽  
Senthil Kumar Velusamy
Keyword(s):  
Host Defense ◽  
Host Response ◽  
Oral Microbiota ◽  
Local Damage ◽  
Distinct Form ◽  
Host Environment ◽  
Microbial Dysbiosis ◽  
Localized Juvenile Periodontitis ◽  
History Of ◽  
Local Host

Aggregatibacter actinomycetemcomitans, the focus of this review, was initially proposed as a microbe directly related to a phenotypically distinct form of periodontitis called localized juvenile periodontitis. At the time, it seemed as if specific microbes were implicated as the cause of distinct forms of disease. Over the years, much has changed. The sense that specific microbes relate to distinct forms of disease has been challenged, as has the sense that distinct forms of periodontitis exist. This review consists of two components. The first part is presented as a detective story where we attempt to determine what role, if any, Aggregatibacter plays as a participant in disease. The second part describes landscape ecology in the context of how the host environment shapes the framework of local microbial dysbiosis. We then conjecture as to how the local host response may limit the damage caused by pathobionts. We propose that the host may overcome the constant barrage of a dysbiotic microbiota by confining it to a local tooth site. We conclude speculating that the host response can confine local damage by restricting bacteremic translocation of members of the oral microbiota to distant organs thus constraining morbidity and mortality of the host.

scholarly journals Oral microbial dysbiosis and its performance in predicting oral cancer

2020 ◽  
Author(s):  
Shih-Chi Su ◽  
Lun-Ching Chang ◽  
Hsien-Da Huang ◽  
Chih-Yu Peng ◽  
Chun-Yi Chuang ◽  
...  
Keyword(s):  
Oral Cancer ◽  
Fusobacterium Nucleatum ◽  
Risky Behaviors ◽  
Health Condition ◽  
Oral Microbiome ◽  
Oral Microbiota ◽  
Microbial Dysbiosis ◽  
Anti Cancer ◽  
Betel Quid Chewing ◽  
Male Patients

Abstract Dysbiosis of oral microbiome may dictate the progression of oral squamous cell carcinoma (OSCC). Yet, the composition of oral microbiome fluctuates by saliva and distinct sites of oral cavity and is affected by risky behaviors (smoking, drinking and betel quid chewing) and individuals’ oral health condition. To characterize the disturbances in the oral microbial population mainly due to oral tumorigenicity, we profiled the bacteria within the surface of OSCC lesion and its contralateral normal tissue from discovery (n = 74) and validation (n = 42) cohorts of male patients with cancers of the buccal mucosa. Significant alterations in the bacterial diversity and relative abundance of specific oral microbiota (most profoundly, an enrichment for genus Fusobacterium and the loss of genus Streptococcus in the tumor sites) were identified. Functional prediction of oral microbiome shown that microbial genes related to the metabolism of terpenoids and polyketides were differentially enriched between the control and tumor groups, indicating a functional role of oral microbiome in formulating a tumor microenvironment via attenuated biosynthesis of secondary metabolites with anti-cancer effects. Furthermore, the vast majority of microbial signatures detected in the discovery cohort was generalized well to the independent validation cohort, and the clinical validity of these OSCC-associated microbes was observed and successfully replicated. Overall, our analyses reveal signatures (a profusion of Fusobacterium nucleatum CTI-2 and a decrease in Streptococcus pneumoniae) and functions (decreased production of tumor-suppressive metabolites) of oral microbiota related to oral cancer.

scholarly journals A Brief History of Race, Politics and Division in Trinidad and Guyana

2020 ◽  
Vol 5 ◽  
pp. 44-54
Author(s):  
Kahlia Brown
Keyword(s):  
Political Parties ◽  
Trinidad And Tobago ◽  
Racial Politics ◽  
Distinct Form ◽  
Race Politics ◽  
Large Numbers ◽  
Form Of Government ◽  
History Of ◽  
Racial Divide ◽  
History Of Race

This essay will act as an analysis of the Indo-Afro racial politics of two west Indian countries: Trinidad and Tobago, and Guyana. I will give the circumstances that led to the migration of large numbers of East Indians as indentured servants to Trinidad and Guyana, specifically. I will also explain how these conditions led to a distinct form of government and society. Through tables of electoral data in Trinidad, the racial voting patterns will be observed, and I will elaborate on how political parties do or do not pander to their respective racial communities. Finally, I will conclude by addressing how the racial divide in these two large Caribbean nations impact Caribbean regionalism on a larger scale.

scholarly journals Immune Immunomodulation in Coronavirus Disease 2019 (COVID-19): Strategic Considerations for Personalized Therapeutic Intervention

2020 ◽  
Author(s):  
Mark W Hall ◽  
Ila Joshi ◽  
Luis Leal ◽  
Eng Eong Ooi
Keyword(s):  
Immune Response ◽  
Critical Illness ◽  
Severe Acute Respiratory Syndrome ◽  
Systemic Inflammation ◽  
Host Defense ◽  
Shortest Path ◽  
Immune Suppression ◽  
Host Response ◽  
Repair Mechanisms ◽  
Anticytokine Therapy

Abstract We are learning that the host response to severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2) infection is complex and highly dynamic. Effective initial host defense in the lung is associated with mild symptoms and disease resolution. Viral evasion of the immune response can lead to refractory alveolar damage, ineffective lung repair mechanisms, and systemic inflammation with associated organ dysfunction. The immune response in these patients is highly variable and can include moderate to severe systemic inflammation and/or marked systemic immune suppression. There is unlikely to be a “one size fits all” approach to immunomodulation in patients with coronavirus disease 2019 (COVID-19). We believe that a personalized, immunophenotype-driven approach to immunomodulation that may include anticytokine therapy in carefully selected patients and immunostimulatory therapies in others is the shortest path to success in the study and treatment of patients with critical illness due to COVID-19.

scholarly journals Host defense against oral microbiota by bone-damaging T cells

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Masayuki Tsukasaki ◽  
Noriko Komatsu ◽  
Kazuki Nagashima ◽  
Takeshi Nitta ◽  
Warunee Pluemsakunthai ◽  
...  
Keyword(s):  
T Cells ◽  
Host Defense ◽  
Oral Microbiota

Unmasking cellular response of a bloom-forming alga to virus infection by resolving expression profiling at a single-cell level

2017 ◽  
Author(s):  
Shilo Rosenwasser ◽  
Miguel J. Frada ◽  
David Pilzer ◽  
Ron Rotkopf ◽  
Assaf Vardi
Keyword(s):  
Gene Expression ◽  
Viral Infection ◽  
Single Cell ◽  
Host Defense ◽  
Host Response ◽  
Expression Profiles ◽  
Life Cycles ◽  
Viral Gene ◽  
Single Cell Level ◽  
Cell Level

AbstractMarine viruses are major evolutionary and biogeochemical drivers of microbial life in the ocean. Host response to viral infection typically includes virus-induced rewiring of metabolic network to supply essential building blocks for viral assembly, as opposed to activation of anti-viral host defense. Nevertheless, there is a major bottleneck to accurately discern between viral hijacking strategies and host defense responses when averaging bulk population response. Here we use Emiliania huxleyi, a bloom-forming alga and its specific virus (EhV), as one of the most ecologically important host-virus model system in the ocean. Using automatic microfluidic setup to capture individual algal cells, we quantified host and virus gene expression on a single-cell resolution during the course of infection. We revealed high heterogeneity in viral gene expression among individual cells. Simultaneous measurements of expression profiles of host and virus genes at a single-cell level allowed mapping of infected cells into newly defined infection states and uncover a yet unrecognized early phase in host response that occurs prior to viral expression. Intriguingly, resistant cells emerged during viral infection, showed unique expression profiles of metabolic genes which can provide the basis for discerning between viral resistant and sensitive cells within heterogeneous populations in the marine environment. We propose that resolving host-virus arms race at a single-cell level will provide important mechanistic insights into viral life cycles and will uncover host defense strategies.

scholarly journals Interleukin-10 Negatively Regulates Local Cytokine and Chemokine Production but Does Not Influence Antibacterial Host Defense during Murine Pneumococcal Meningitis

2003 ◽  
Vol 71 (4) ◽  
pp. 2276-2279 ◽  
Author(s):  
Petra J. G. Zwijnenburg ◽  
Tom van der Poll ◽  
Sandrine Florquin ◽  
John J. Roord ◽  
A. Marceline van Furth
Keyword(s):  
Host Defense ◽  
Pneumococcal Meningitis ◽  
Inflammatory Responses ◽  
Interleukin 10 ◽  
Wild Type ◽  
Chemokine Production ◽  
Local Host ◽  
Antibacterial Host Defense ◽  
Local Cytokine

ABSTRACT To determine the role of endogenous interleukin-10 (IL-10) in local host defense during pneumococcal meningitis, the inflammatory responses of IL-10-gene-deficient and wild-type mice after the induction of meningitis were compared. The absence of IL-10 was associated with higher cytokine and chemokine concentrations and a more pronounced infiltrate, but antibacterial defense or survival was not influenced.

scholarly journals Aggregatibacter Actinomycetemcomitans: Clinical Significance of a Pathobiont Subjected to Ample Changes in Classification and Nomenclature

2019 ◽  
Author(s):  
Niels Nørskov-Lauritsen ◽  
Rolf Claesson ◽  
Anne Birkeholm Jensen ◽  
Carola Höglund-Åberg ◽  
Dorte Haubek
Keyword(s):  
Clinical Significance ◽  
Host Response ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Oral Microbiota ◽  
Aetiological Agent ◽  
Negative Bacterium ◽  
Complex Interplay ◽  
Gram Negative ◽  
Oral Infections ◽  
Exclusive Or

Aggregatibacter actinomycetemcomitans is a Gram-negative bacterium that is part of the oral microbiota. The aggregative nature of this pathogen or pathobiont is crucial to its involvement in human disease. It has been cultured from non-oral infections for more than a century, while the portrayal as an aetiological agent in periodontitis has emerged more recently. Although A. actinomycetemcomitans encodes several putative toxins, the complex interplay with other partners of the oral microbiota and the suppression of the initial host response may be central for inflammation and infection in the oral cavity. The aim of this review is to provide a comprehensive update on the clinical significance, classification, and characterisation of A. actinomycetemcomitans, which has exclusive or predominant host specificity for humans.

scholarly journals Adaptation by Ancient Horizontal Acquisition of Butyrate Metabolism Genes in Aggregatibacter actinomycetemcomitans

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Ahmed M. Moustafa ◽  
Senthil Kumar Velusamy ◽  
Lidiya Denu ◽  
Apurva Narechania ◽  
Daniel H. Fine ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Strong Association ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Short Chain ◽  
Oral Microbiota ◽  
Content Type ◽  
History Of ◽  
The Impact

ABSTRACT Like the bacterial residents of the human gut, it is likely that many of the species in the human oral microbiota have evolved to better occupy and persist in their niche. Aggregatibacter actinomycetemcomitans (Aa) is both a common colonizer of the oral cavity and has been implicated in the pathogenesis of periodontal disease. Here, we present a whole-genome phylogenetic analysis of Aa isolates from humans and nonhuman primates that revealed an ancient origin for this species and a long history of association with the Catarrhini, the lineage that includes Old World monkeys (OWM) and humans. Further genomic analysis showed a strong association with the presence of a short-chain fatty acid (SCFA) catabolism locus (atoRDAEB) in many human isolates that was absent in almost all nonhuman OWM isolates. We show that this locus was likely acquired through horizontal gene transfer. When grown under conditions that are similar to those at the subgingival site of periodontitis (anaerobic, SCFA replete), Aa strains with atoRDAEB formed robust biofilms and showed upregulation of genes involved in virulence, colonization, and immune evasion. Both an isogenic deletion mutant and nonhuman primate isolates lacking the ato locus failed to grow in a robust biofilm under these conditions, but grew well under the carbohydrate-rich conditions similar to those found above the gumline. We propose that the acquisition of the ato locus was a key evolutionary step allowing Aa to utilize SCFAs, adapt, and modulate subgingival disease. IMPORTANCE There has been considerable interest in the impact of short-chain fatty acids (SCFAs) on inflammatory effects related to the microbiome. Here, we present evidence that SCFAs may also be important in disease by providing an energy source or disease-associated cue for colonizing pathogens. We propose that SCFAs allow Aggregatibacter actinomycetemcomitans (Aa) to adapt to the subgingival anaerobic environment, which is the site of human periodontitis. Under anaerobic, SCFA-rich conditions, human-derived Aa strains that possess butyrate metabolism genes form strong biofilms and upregulate virulence genes. Our phylogenetic analysis highlights a long history of evolution of Aa with its primate hosts and suggests that the acquisition of butyrate metabolism genes may have been a critical step in allowing Aa to colonize a new niche and cause disease in humans. Overall, this study highlights the important role that horizontal gene transfer may play in microbial adaptation and the evolution of infectious disease.

scholarly journals Meta-analysis suggests the microbiome responds to Evolve and Resequence experiments in Drosophila melanogaster

2020 ◽  
Author(s):  
Lucas P Henry ◽  
Julien F Ayroles
Keyword(s):  
Drosophila Melanogaster ◽  
Bacterial Diversity ◽  
Experimental Evolution ◽  
Host Selection ◽  
Host Response ◽  
Meta Analysis ◽  
Response To Selection ◽  
Evolutionary Processes ◽  
History Of ◽  
Host Evolution

Experimental evolution has a long history of uncovering fundamental insights into evolutionary processes but has largely neglected one underappreciated component--the microbiome. As eukaryotic hosts evolve, the microbiome may also evolve in response. However, the microbial contribution to host evolution remains poorly understood. Here, we analyzed the metagenomes from 10 E&R experiments in Drosophila melanogaster to determine how the microbiome changes in response to host selection. Bacterial diversity was significantly different in 5/10 studies in traits associated with metabolism or immunity. Additionally, we find that excluding reads from a facultative symbiont, Wolbachia, in the analysis of bacterial diversity changes the inference, raising important questions for future E&R experiments in D. melanogaster. Our results suggest the microbiome often responds to host selection but highlights the need for more work to understand how the microbiome changes the host response to selection.

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