scholarly journals Dynamic modelling of viral impact on cyanobacterial populations in shallow lakes: implications of burst size

2006 ◽  
Vol 86 (3) ◽  
pp. 537-542 ◽  
Author(s):  
Herman J. Gons ◽  
Hans L. Hoogveld ◽  
Stefan G.H. Simis ◽  
Marjolijn Tijdens
Keyword(s):  
Burst Size ◽  
Dynamic Modelling ◽  
Nutrient Status ◽  
Host Cells ◽  
Ecological Implication ◽  
Eutrophic Lakes ◽  
Host Interaction ◽  
Water Columns ◽  
Single Host ◽  
Large Burst

Laboratory experiments with whole water-columns from shallow, eutrophic lakes repeatedly showed collapse of the predominant filamentous cyanobacteria. The collapse could be due to viral activity, from the evidence of electron microscopy of infected cyanobacterial cells and observed dynamics of virus-like particles. Burst-size effects on single-host single-virus dynamics was modelled for nutrient-replete growth of the cyanobacteria and fixed viral decay rate in the water column. The model combined previously published equations for nutrient-replete cyanobacterial growth and virus–host relationship. According to the model results, burst sizes greater than 200 to 400 virions per cell would result in host extinction, whereas lower numbers would allow coexistence, and even stable population densities of host and virus. High-nutrient status of the host cells might accommodate a large burst size. The ecological implication could be that burst-size increase accompanying a transition from phosphorus to light-limited cyanobacterial growth might destabilize the virus–host interaction and result in the population collapse observed in the experiments.

scholarly journals Revisiting Ehrlichia ruminantium Replication Cycle Using Proteomics: The Host and the Bacterium Perspectives

2021 ◽  
Vol 9 (6) ◽  
pp. 1144
Author(s):  
Isabel Marcelino ◽  
Philippe Holzmuller ◽  
Ana Coelho ◽  
Gabriel Mazzucchelli ◽  
Bernard Fernandez ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Host Cell ◽  
Cell Metabolism ◽  
Replication Cycle ◽  
Host Cells ◽  
Ehrlichia Ruminantium ◽  
Host Interaction ◽  
Infected Cells ◽  
Related Proteins

The Rickettsiales Ehrlichia ruminantium, the causal agent of the fatal tick-borne disease Heartwater, induces severe damage to the vascular endothelium in ruminants. Nevertheless, E. ruminantium-induced pathobiology remains largely unknown. Our work paves the way for understanding this phenomenon by using quantitative proteomic analyses (2D-DIGE-MS/MS, 1DE-nanoLC-MS/MS and biotin-nanoUPLC-MS/MS) of host bovine aorta endothelial cells (BAE) during the in vitro bacterium intracellular replication cycle. We detect 265 bacterial proteins (including virulence factors), at all time-points of the E. ruminantium replication cycle, highlighting a dynamic bacterium–host interaction. We show that E. ruminantium infection modulates the expression of 433 host proteins: 98 being over-expressed, 161 under-expressed, 140 detected only in infected BAE cells and 34 exclusively detected in non-infected cells. Cystoscape integrated data analysis shows that these proteins lead to major changes in host cell immune responses, host cell metabolism and vesicle trafficking, with a clear involvement of inflammation-related proteins in this process. Our findings led to the first model of E. ruminantium infection in host cells in vitro, and we highlight potential biomarkers of E. ruminantium infection in endothelial cells (such as ROCK1, TMEM16K, Albumin and PTPN1), which may be important to further combat Heartwater, namely by developing non-antibiotic-based strategies.

scholarly journals Cyanobiont-bearing Dinoflagellate Ornithocercus in Temperate Coastal Waters: Cyanobiont Genetic Diversity and Host Specificity

2020 ◽  
Author(s):  
Miran Kim ◽  
Dong Choi ◽  
Myung Park
Keyword(s):  
Genetic Diversity ◽  
Coastal Waters ◽  
Host Cells ◽  
Genetic Types ◽  
Four Seasons ◽  
Wide Range ◽  
Single Host ◽  
Unicellular Organisms ◽  
Miseq Platform ◽  
Bacterial Groups

Abstract Cyanobacteria are ubiquitous in marine environments and play an important role as primary producers. Some cyanobacteria, the so called cyanobionts (cyanobacterial symbionts), have a symbiotic relationship with unicellular organisms. Among these relationships, in particular, the nature (e.g., genetic diversity, host or cyanobiont specificity, and cyanobionts seasonality) of the cyanobionts-dinoflagellate host consortia remain poorly understood. In this study, 16S rDNA of cyanobionts in a total of 138 single host cells isolated over four seasons in temperate waters were sequenced using the MiSeq platform. Genetic analysis of cyanobionts from the dinoflagellate host Ornithocercus revealed that three genetic types of Synechococcales cyanobionts occurred at a wide range of water temperatures (11–24°C) and their distribution seems to be closely associated with the variation in salinity. Furthermore, this study showed the presence of some degree of host (or cyanobiont) specificity in cyanobionts (or host) among Ornithocercus species as well as among other dinophysoid species (i.e. Amphisolenia, Citharistes, and Histioneis). In addition to Synechococcales cyanobionts, this study identified some OTU sequences affiliated with the Vampirovibrionales and Chroococcidiopsidales in some Ornithocercus cells, suggesting that Ornithocercus species seem to be an additional new habitat for those bacterial groups.

HERBAL FORMULATION (IMMUHELP) IN THE MANAGEMENT OF UPPER RESPIRATORY TRACT INFECTION.

2021 ◽  
pp. 10-19
Author(s):  
Yamini Bhusan Tripathi ◽  
Priyanka Mishra ◽  
Harsh Pandey ◽  
Priya Shree ◽  
Nikhil Pandey ◽  
...  
Keyword(s):  
Medicinal Plants ◽  
Tract Infection ◽  
Respiratory Tract ◽  
Respiratory Tract Infection ◽  
Animal Experiments ◽  
Upper Respiratory Tract Infection ◽  
Host Cells ◽  
Upper Respiratory Tract ◽  
Host Interaction ◽  
Upper Respiratory

The Upper respiratory tract infection is mainly attributed to viral infections so focus should be given to inhibition of viral-host interaction, their entry and replication in the host cells and release of inammatory st cytokines, resulting physiological disturbances. The host's immune system is the 1 line of defence against such threats so multitargeted herbal immune-boosters, with antioxidant, anti-inammatory and tissue repair potential would be preferred. The natural cocktail of medicinal plants has shown promising results both by using bioinformatics based drug docking studies, in animal experiments and in clinical trials. Here we have reviewed the 6-medicinal plants, used in making “Immuhelp”, towards their established role in management of viral-host interaction, activation of innate and adaptive immunity, inhibition-potential against release of inammatory cytokines, immunosuppressive and chemoattractant agents and antioxidant potentials.

scholarly journals The Regulation of Flavivirus Infection by Hijacking Exosome-Mediated Cell–Cell Communication: New Insights on Virus–Host Interactions

Viruses ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 765
Author(s):  
José Manuel Reyes-Ruiz ◽  
Juan Fidel Osuna-Ramos ◽  
Luis Adrián De Jesús-González ◽  
Selvin Noé Palacios-Rápalo ◽  
Carlos Daniel Cordero-Rivera ◽  
...  
Keyword(s):  
Viral Infections ◽  
Cell Communication ◽  
Cell Interaction ◽  
Host Cells ◽  
Human Pathogens ◽  
Cellular Functions ◽  
Cellular Targets ◽  
Host Interaction ◽  
Flavivirus Infection

The arthropod-borne flaviviruses are important human pathogens, and a deeper understanding of the virus–host cell interaction is required to identify cellular targets that can be used as therapeutic candidates. It is well reported that the flaviviruses hijack several cellular functions, such as exosome-mediated cell communication during infection, which is modulated by the delivery of the exosomal cargo of pro- or antiviral molecules to the receiving host cells. Therefore, to study the role of exosomes during flavivirus infections is essential, not only to understand its relevance in virus–host interaction, but also to identify molecular factors that may contribute to the development of new strategies to block these viral infections. This review explores the implications of exosomes in flavivirus dissemination and transmission from the vector to human host cells, as well as their involvement in the host immune response. The hypothesis about exosomes as a transplacental infection route of ZIKV and the paradox effect or the dual role of exosomes released during flavivirus infection are also discussed here. Although several studies have been performed in order to identify and characterize cellular and viral molecules released in exosomes, it is not clear how all of these components participate in viral pathogenesis. Further studies will determine the balance between protective and harmful exosomes secreted by flavivirus infected cells, the characteristics and components that distinguish them both, and how they could be a factor that determines the infection outcome.

scholarly journals Expression of a Single, Host-Specific, Bacterial Pathogenicity Gene in Plant Cells Elicits Division, Enlargement, and Cell Death

1999 ◽  
Vol 12 (6) ◽  
pp. 556-560 ◽  
Author(s):  
Y. P. Duan ◽  
A. Castañeda ◽  
G. Zhao ◽  
G. Erdos ◽  
D. W. Gabriel
Keyword(s):  
Single Gene ◽  
Plant Cells ◽  
Host Cells ◽  
Microbial Pathogens ◽  
Bacterial Pathogenicity ◽  
Site Of Action ◽  
Single Host ◽  
Protein Secretion System ◽  
Type Iii Protein Secretion ◽  
Specific Symptoms

A fundamental question about microbial pathogens is how they elicit host-specific symptoms. We report here that expression of a single gene from a plant-pathogenic bacterium in plant cells elicits host-specific symptoms diagnostic of the disease caused by the pathogen. Expression of pthA from Xanthomonas citri in citrus cells is sufficient to cause division, enlargement, and death of host cells. Since elicitation of these symptoms depends on a functional type III protein secretion system in X. citri, we deduce that the PthA protein is a specific plant signal, its site of action is inside the plant cell, and it is a major determinant of host range.

scholarly journals Sulfated Glycans and Related Digestive Enzymes in the Zika Virus Infectivity: Potential Mechanisms of Virus-Host Interaction and Perspectives in Drug Discovery

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Vitor H. Pomin
Keyword(s):  
Neural Development ◽  
Zika Virus ◽  
Molecular Mechanisms ◽  
Surface Proteins ◽  
Host Cells ◽  
Future Research ◽  
Virus Infectivity ◽  
Virus Attachment ◽  
Chemical Structures ◽  
Host Interaction

As broadly reported, there is an ongoing Zika virus (ZIKV) outbreak in countries of Latin America. Recent findings have demonstrated that ZIKV causes severe defects on the neural development in fetuses in utero and newborns. Very little is known about the molecular mechanisms involved in the ZIKV infectivity. Potential therapeutic agents are also under investigation. In this report, the possible mechanisms of action played by glycosaminoglycans (GAGs) displayed at the surface proteoglycans of host cells, and likely in charge of interactions with surface proteins of the ZIKV, are highlighted. As is common for the most viruses, these sulfated glycans serve as receptors for virus attachment onto the host cells and consequential entry during infection. The applications of (1) exogenous sulfated glycans of different origins and chemical structures capable of competing with the virus attachment receptors (supposedly GAGs) and (2) GAG-degrading enzymes able to digest the virus attachment receptors on the cells may be therapeutically beneficial as anti-ZIKV. This communication attempts, therefore, to offer some guidance for the future research programs aimed to unveil the molecular mechanisms underlying the ZIKV infectivity and to develop therapeutics capable of decreasing the devastating consequences caused by ZIKV outbreak in the Americas.

scholarly journals Surface Glycans of Candida albicans and Other Pathogenic Fungi: Physiological Roles, Clinical Uses, and Experimental Challenges

2004 ◽  
Vol 17 (2) ◽  
pp. 281-310 ◽  
Author(s):  
James Masuoka
Keyword(s):  
Fungal Infections ◽  
Pathogenic Fungi ◽  
Host Cells ◽  
Composition Analysis ◽  
Fungal Cell ◽  
Whole Cells ◽  
Host Interaction ◽  
Rapid Characterization ◽  
Cell Fractions

SUMMARY Although fungi have always been with us as commensals and pathogens, fungal infections have been increasing in frequency over the past few decades. There is a growing body of literature describing the involvement of carbohydrate groups in various aspects of fungal disease. Carbohydrates comprising the cell wall or capsule, or as a component of glycoproteins, are the fungal cell surface entities most likely to be exposed to the surrounding environment. Thus, the fungus-host interaction is likely to involve carbohydrates before DNA, RNA, or even protein. The interaction between fungal and host cells is also complex, and early studies using whole cells or crude cell fractions often produced seemingly conflicting results. What was needed, and what has been developing, is the ability to identify specific glycan structures and determine how they interact with immune system components. Carbohydrate analysis is complicated by the complexity of glycan structures and by the challenges of separating and detecting carbohydrates experimentally. Advances in carbohydrate chemistry have enabled us to move from the foundation of composition analysis to more rapid characterization of specific structures. This, in turn, will lead to a greater understanding of how fungi coexist with their hosts as commensals or exist in conflict as pathogens.

scholarly journals Fitness benefits of low infectivity in a spatially structured population of bacteriophages

2014 ◽  
Vol 281 (1774) ◽  
pp. 20132563 ◽  
Author(s):  
Pavitra Roychoudhury ◽  
Neelima Shrestha ◽  
Valorie R. Wiss ◽  
Stephen M. Krone
Keyword(s):  
Transmission Rate ◽  
Burst Size ◽  
Structured Populations ◽  
Host Cells ◽  
Structured Population ◽  
Spatially Structured Populations ◽  
Lysis Time ◽  
Evolution Experiment ◽  
Spatially Structured Population ◽  
And Diffusion

For a parasite evolving in a spatially structured environment, an evolutionarily advantageous strategy may be to reduce its transmission rate or infectivity. We demonstrate this empirically using bacteriophage (phage) from an evolution experiment where spatial structure was maintained over 550 phage generations on agar plates. We found that a single substitution in the major capsid protein led to slower adsorption of phage to host cells with no change in lysis time or burst size. Plaques formed by phage isolates containing this mutation were not only larger but also contained more phage per unit area. Using a spatially explicit, individual-based model, we showed that when there is a trade-off between adsorption and diffusion (i.e. less ‘sticky’ phage diffuse further), slow adsorption can maximize plaque size, plaque density and overall productivity. These findings suggest that less infective pathogens may have an advantage in spatially structured populations, even when well-mixed models predict that they will not.

scholarly journals Mathematical Analysis of Growth and Interaction Dynamics of Streptomycetes and a Bacteriophage in Soil

2000 ◽  
Vol 66 (9) ◽  
pp. 3868-3877 ◽  
Author(s):  
N. J. Burroughs ◽  
P. Marsh ◽  
E. M. H. Wellington
Keyword(s):  
Liquid Culture ◽  
Burst Size ◽  
Agar Plate ◽  
Quantitative Agreement ◽  
Host Population ◽  
Soil Environment ◽  
Host Interaction ◽  
Primary Determinant ◽  
Host Life ◽  
Underlying Mechanisms

ABSTRACT We observed the infection cycle of the temperate actinophage KC301 in relation to the growth of its host Streptomyces lividansTK24 in sterile soil microcosms. Despite a large increase in phage population following germination of host spores, there was no observable impact on host population numbers as measured by direct plate counts. The only change in the host population following infection was the establishment of a small subpopulation of KC301 lysogens. The interaction of S. lividans and KC301 in soil was analyzed with a population-dynamic mathematical model to determine the underlying mechanisms of this low susceptibility to phage attack relative to aquatic environments. This analysis suggests that the soil environment is a highly significant component of the phage-host interaction, an idea consistent with earlier observations on the importance of the environment in determining host growth and phage-host dynamics. Our results demonstrate that the accepted phage-host interaction and host life cycle, as determined from agar plate studies and liquid culture, is sufficient for quantitative agreement with observations in soil, using soil-determined rates. There are four significant effects of the soil environment: (i) newly germinated spores are more susceptible to phage lysis than are hyphae of developed mycelia, (ii) substrate mycelia in mature colonies adsorb about 98% of the total phage protecting susceptible young hyphae from infection, (iii) the burst size of KC301 is large in soil (>150, 90% confidence) relative to that observed in liquid culture (120, standard error of the mean [SEM], 6), and (iv) there is no measurable impact on the host in terms of reduced growth by the phage. We hypothesize that spatial heterogeneity is the principal cause of these effects and is the primary determinant in bacterial escape of phage lysis in soil.

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