scholarly journals Focal Point Theory Models for Dissecting Dynamic Duality Problems of Microbial Infections

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
S.-H. Huang ◽  
W. Zhou ◽  
A. Jong
Keyword(s):  
Microbial Communities ◽  
Focal Point ◽  
Fundamental Problem ◽  
Point Theory ◽  
Microbial Infection ◽  
Dynamic Interactions ◽  
Microbial Infections ◽  
Specific Pathogen ◽  
Rational Control ◽  
Dynamic Duality

Extending along the dynamic continuum from conflict to cooperation, microbial infections always involve symbiosis (Sym) and pathogenesis (Pat). There exists a dynamic Sym-Pat duality (DSPD) in microbial infection that is the most fundamental problem in infectomics. DSPD is encoded by the genomes of both the microbes and their hosts. Three focal point (FP) theory-based game models (pure cooperative, dilemma, and pure conflict) are proposed for resolving those problems. Our health is associated with the dynamic interactions of three microbial communities (nonpathogenic microbiota (NP) (Cooperation), conditional pathogens (CP) (Dilemma), and unconditional pathogens (UP) (Conflict)) with the hosts at different health statuses. Sym and Pat can be quantitated by measuring symbiotic index (SI), which is quantitative fitness for the symbiotic partnership, and pathogenic index (PI), which is quantitative damage to the symbiotic partnership, respectively. Symbiotic point (SP), which bears analogy to FP, is a function of SI and PI. SP-converting and specific pathogen-targeting strategies can be used for the rational control of microbial infections.

scholarly journals Interspecies Interactions within Oral Microbial Communities

2007 ◽  
Vol 71 (4) ◽  
pp. 653-670 ◽  
Author(s):  
Howard K. Kuramitsu ◽  
Xuesong He ◽  
Renate Lux ◽  
Maxwell H. Anderson ◽  
Wenyuan Shi
Keyword(s):  
Microbial Communities ◽  
Focal Point ◽  
Bacterial Species ◽  
System Thinking ◽  
Learning System ◽  
Interspecies Interaction ◽  
Interspecies Interactions ◽  
Microbial Infections ◽  
New Research ◽  
Polymicrobial Disease

SUMMARY While reductionism has greatly advanced microbiology in the past 400 years, assembly of smaller pieces just could not explain the whole! Modern microbiologists are learning “system thinking” and “holism.” Such an approach is changing our understanding of microbial physiology and our ability to diagnose/treat microbial infections. This review uses oral microbial communities as a focal point to describe this new trend. With the common name “dental plaque,” oral microbial communities are some of the most complex microbial floras in the human body, consisting of more than 700 different bacterial species. For a very long time, oral microbiologists endeavored to use reductionism to identify the key genes or key pathogens responsible for oral microbial pathogenesis. The limitations of reductionism forced scientists to begin adopting new strategies using emerging concepts such as interspecies interaction, microbial community, biofilms, polymicrobial disease, etc. These new research directions indicate that the whole is much more than the simple sum of its parts, since the interactions between different parts resulted in many new physiological functions which cannot be observed with individual components. This review describes some of these interesting interspecies-interaction scenarios.

scholarly journals Effects of Malachite Green on the Microbiomes of Milkfish Culture Ponds

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 411
Author(s):  
Chu-Wen Yang ◽  
Yi-Tang Chang ◽  
Chi-Yen Hsieh ◽  
Bea-Ven Chang
Keyword(s):  
Infectious Diseases ◽  
Microbial Communities ◽  
Malachite Green ◽  
Fish Farming ◽  
Cyanobacterial Blooms ◽  
Anoxygenic Phototrophic Bacteria ◽  
Fish Mortality ◽  
Veterinary Drug ◽  
Degrading Bacteria ◽  
Microbial Infections

Intensive fish farming through aquaculture is vulnerable to infectious diseases that can increase fish mortality and damage the productivity of aquaculture farms. To prevent infectious diseases, malachite green (MG) has been applied as a veterinary drug for various microbial infections in aquaculture settings worldwide. However, little is known regarding the consequences of MG and MG-degrading bacteria (MGDB) on microbial communities in milkfish culture ponds (MCPs). In this study, small MCPs were used as a model system to determine the effects of MG on the microbial communities in MCPs. The addition of MG led to cyanobacterial blooms in the small MCP. The addition of MGDB could not completely reverse the effects of MG on microbial communities. Cyanobacterial blooms were not prevented. Microbial communities analyzed by next generation sequencing revealed that cyanobacterial blooms may be due to increase of nitrogen cycle (including nitrogen fixation, nitrate reduction and anammox) associated microbial communities, which raised the levels of ammonium in the water of the small MCP. The communities of anoxygenic phototrophic bacteria (beneficial for aquaculture and aquatic ecosystems) decreased after the addition of MG. The results of this investigation provide valuable insights into the effects of MG in aquaculture and the difficulties of bioremediation for aquatic environments polluted by MG.

Detection of Microbial Infections Through Innate Immune Sensing of Nucleic Acids

2018 ◽  
Vol 72 (1) ◽  
pp. 447-478 ◽  
Author(s):  
Xiaojun Tan ◽  
Lijun Sun ◽  
Jueqi Chen ◽  
Zhijian J. Chen
Keyword(s):  
Nucleic Acid ◽  
Nucleic Acids ◽  
Immune Defense ◽  
Innate Immune ◽  
Type I Interferons ◽  
Microbial Pathogens ◽  
Type I ◽  
Immune Recognition ◽  
Microbial Infection ◽  
Microbial Infections

Microbial infections are recognized by the innate immune system through germline-encoded pattern recognition receptors (PRRs). As most microbial pathogens contain DNA and/or RNA during their life cycle, nucleic acid sensing has evolved as an essential strategy for host innate immune defense. Pathogen-derived nucleic acids with distinct features are recognized by specific host PRRs localized in endolysosomes and the cytosol. Activation of these PRRs triggers signaling cascades that culminate in the production of type I interferons and proinflammatory cytokines, leading to induction of an antimicrobial state, activation of adaptive immunity, and eventual clearance of the infection. Here, we review recent progress in innate immune recognition of nucleic acids upon microbial infection, including pathways involving endosomal Toll-like receptors, cytosolic RNA sensors, and cytosolic DNA sensors. We also discuss the mechanisms by which infectious microbes counteract host nucleic acid sensing to evade immune surveillance.

scholarly journals STING signaling and host defense against microbial infection

2019 ◽  
Vol 51 (12) ◽  
pp. 1-10 ◽  
Author(s):  
Jeonghyun Ahn ◽  
Glen N. Barber
Keyword(s):  
Host Defense ◽  
Innate Immune ◽  
Type I Interferons ◽  
Type I ◽  
Microbial Infection ◽  
Immune Signaling ◽  
Pathogen Invasion ◽  
Innate Immune Signaling ◽  
Specific Pathogen ◽  
Microbial Dna

AbstractThe first line of host defense against infectious agents involves activation of innate immune signaling pathways that recognize specific pathogen-associated molecular patterns (PAMPs). Key triggers of innate immune signaling are now known to include microbial-specific nucleic acid, which is rapidly detected in the cytosol of the cell. For example, RIG-I-like receptors (RLRs) have evolved to detect viral RNA species and to activate the production of host defense molecules and cytokines that stimulate adaptive immune responses. In addition, host defense countermeasures, including the production of type I interferons (IFNs), can also be triggered by microbial DNA from bacteria, viruses and perhaps parasites and are regulated by the cytosolic sensor, stimulator of interferon genes (STING). STING-dependent signaling is initiated by cyclic dinucleotides (CDNs) generated by intracellular bacteria following infection. CDNs can also be synthesized by a cellular synthase, cGAS, following interaction with invasive cytosolic self-DNA or microbial DNA species. The importance of STING signaling in host defense is evident since numerous pathogens have developed strategies to prevent STING function. Here, we review the relevance of STING-controlled innate immune signaling in host defense against pathogen invasion, including microbial endeavors to subvert this critical process.

scholarly journals A three-dimensional culture system recapitulates placental syncytiotrophoblast development and microbial resistance

2016 ◽  
Vol 2 (3) ◽  
pp. e1501462 ◽  
Author(s):  
Cameron A. McConkey ◽  
Elizabeth Delorme-Axford ◽  
Cheryl A. Nickerson ◽  
Kwang Sik Kim ◽  
Yoel Sadovsky ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Maternal Blood ◽  
Microbial Infection ◽  
Microbial Resistance ◽  
Fetal Protection ◽  
Multinucleated Cells ◽  
Culture Model ◽  
Microbial Infections ◽  
Cells Cultured

In eutherians, the placenta acts as a barrier and conduit at the maternal-fetal interface. Syncytiotrophoblasts, the multinucleated cells that cover the placental villous tree surfaces of the human placenta, are directly bathed in maternal blood and are formed by the fusion of progenitor cytotrophoblasts that underlie them. Despite their crucial role in fetal protection, many of the events that govern trophoblast fusion and protection from microbial infection are unknown. We describe a three-dimensional (3D)–based culture model using human JEG-3 trophoblast cells that develop syncytiotrophoblast phenotypes when cocultured with human microvascular endothelial cells. JEG-3 cells cultured in this system exhibit enhanced fusogenic activity and morphological and secretory activities strikingly similar to those of primary human syncytiotrophoblasts. RNASeq analyses extend the observed functional similarities to the transcriptome, where we observed significant overlap between syncytiotrophoblast-specific genes and 3D JEG-3 cultures. Furthermore, JEG-3 cells cultured in 3D are resistant to infection by viruses and Toxoplasma gondii, which mimics the high resistance of syncytiotrophoblasts to microbial infections in vivo. Given that this system is genetically manipulatable, it provides a new platform to dissect the mechanisms involved in syncytiotrophoblast development and microbial resistance.

scholarly journals Effects of Age and Dietary Fibre Level on Caecal Microbial Communities of Conventional and Specific Pathogen-Free Rabbits

2003 ◽  
Vol 15 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Nadia Bennegadi ◽  
Gérard Fonty ◽  
Liliane Millet ◽  
Thierry Gidenne ◽  
Dominique Licois
Keyword(s):  
Microbial Communities ◽  
Dietary Fibre ◽  
Specific Pathogen Free ◽  
Specific Pathogen

Address of the President, Sir Ploward Florey, at the Anniversary Meeting, 30 November 1963

1964 ◽  
Vol 159 (976) ◽  
pp. 393-404
Keyword(s):  
Research Council ◽  
Infected Animal ◽  
Medical Research Council ◽  
Anaerobic Bacteria ◽  
Close Collaboration ◽  
Microbial Infections ◽  
Full Knowledge ◽  
Rational Control ◽  
Opening Up

The Copley Medal is awarded to Sir Paul Fildes, F. R. S. Sir Paul Fildes has the enviable distinction of being the pioneer chiefly responsible for opening up a vast new field of microbiological research. His early studies, over half a century ago, on the growth factors of Haemophilus influenzae and related organisms and his elucidation of conditions requisite for the sporulation and germination of anaerobic bacteria of the tetanus group, both in vitro and in the infected animal, were notable achievements in their own right. Their chief importance, however, lay in the fact that they convinced Fildes that the key to the rational control of microbial infections lay in a full knowledge of the nutritional requirements of the causative organisms and elucidation of the biosynthetic precursors involved in the utilization of essential nutrients. He was probably the first to recognize the necessity of close collaboration between bacteriologists and biochemists for fruitful investigations along this line of approach. To this end he established in 1934, under the auspices of the Medical Research Council, a team which, under his leadership, pioneered the way into the field of bacterial chemistry.

scholarly journals NK-DC Crosstalk in Immunity to Microbial Infection

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Rony Thomas ◽  
Xi Yang
Keyword(s):  
Immune Responses ◽  
Cell Activation ◽  
Nk Cell ◽  
Adaptive Immune Response ◽  
Microbial Infection ◽  
Adaptive Immune ◽  
Microbial Infections ◽  
Cellular Components ◽  
Secondary Lymphoid Organs ◽  
Dc Maturation

The interaction between natural killer (NK) cell and dendritic cell (DC), two important cellular components of innate immunity, started to be elucidated in the last years. The crosstalk between NK cells and DC, which leads to NK cell activation, DC maturation, or apoptosis, involves cell-cell contacts and soluble factors. This interaction either in the periphery or in the secondary lymphoid organs acts as a key player linking innate and adaptive immune responses to microbial stimuli. This review focuses on the mechanisms of NK-DC interaction and their relevance in antimicrobial responses. We specifically aim to emphasize the ability of various microbial infections to differently influence NK-DC crosstalk thereby contributing to distinct adaptive immune response.

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