The infection process of Armillaria mellea and Armillaria solidipes

2020 ◽  
Vol 112 ◽  
pp. 101543
Author(s):  
Pratima Devkota ◽  
Raymond Hammerschmidt
Keyword(s):  
Infection Process ◽  
Armillaria Mellea

Infection of Escherichia coli with bacteriophages

1969 ◽  
Vol 27 ◽  
pp. 370-371
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Nucleic Acid ◽  
Cell Surface ◽  
Virus Type ◽  
Infection Process ◽  
Adsorption Site ◽  
The Other ◽  
Specific Receptors ◽  
Bacterial Receptors

The first step in the infection of a bacterium by a virus consists of a collision between cell and bacteriophage. The presence of virus-specific receptors on the cell surface will trigger a number of events leading eventually to release of the phage nucleic acid. The execution of the various "steps" in the infection process varies from one virus-type to the other, depending on the anatomy of the virus. Small viruses like ØX 174 and MS2 adsorb directly with their capsid to the bacterial receptors, while other phages possess attachment organelles of varying complexity. In bacteriophages T3 (Fig. 1) and T7 the small conical processes of their heads point toward the adsorption site; a welldefined baseplate is attached to the head of P22; heads without baseplates are not infective.

Infection process of wheat streak mosaic virus in clinostated Apogee wheat plants

2003 ◽  
Vol 8 (5-6) ◽  
pp. 211-215 ◽  
Author(s):  
L.T. Mischenko ◽  
◽  
T. Kiihne ◽  
I.A. Mischenko ◽  
A.L. Boyko ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Wheat Streak Mosaic Virus ◽  
Infection Process

POSSIBILITIES OF BIOLOGICAL AND MATHEMATICAL MODELING OF THE INFECTION CAUSED BY EPSTEIN–BARR VIRUS

2020 ◽  
Vol 99 (6) ◽  
pp. 226-231
Author(s):  
A.V. Permyakova ◽  
◽  
A.V. Sazhin ◽  
E.V. Melekhina ◽  
A.V. Gorelov ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Immune Regulation ◽  
Epstein Barr Virus ◽  
Virus Isolation ◽  
Biological Fluids ◽  
Infection Process ◽  
Host Organism ◽  
Barr Virus ◽  
Virus Excretion ◽  
Epstein Barr

The review presents the existing biological and mathematical models of the infection process caused by the Epstein–Barr virus. The existence of the Epstein–Barr virus in the host organism can be described by a model representing a cycle of six consecutive stages, each of them has its own independent variant of immune regulation. The phenomenon of virus excretion in biological fluids, in particular, in saliva, is modeled using differential equations. Usage of mathematical modeling allows us to supplement existing knowledge about the pathogenesis of the infectious process caused by the Epstein–Barr virus, as well as to determine threshold levels of virus isolation in non-sterile environments for the diagnosis of active forms of infection.

scholarly journals Effects of heterogeneity in infection-exposure history and immunity on the dynamics of a protozoan parasite

2007 ◽  
Vol 4 (16) ◽  
pp. 841-849 ◽  
Author(s):  
Maite Severins ◽  
Don Klinkenberg ◽  
Hans Heesterbeek
Keyword(s):  
Dynamic Behaviour ◽  
Protozoan Parasite ◽  
Host Population ◽  
Infection Process ◽  
Control Measures ◽  
Complex Dynamic ◽  
Systems Models ◽  
Exposure History ◽  
The Relationship ◽  
Initial Contamination

Infection systems where traits of the host, such as acquired immunity, interact with the infection process can show complex dynamic behaviour with counter-intuitive results. In this study, we consider the traits ‘immune status’ and ‘exposure history’, and our aim is to assess the influence of acquired individual heterogeneity in these traits. We have built an individual-based model of Eimeria acervulina infections, a protozoan parasite with an environmental stage that causes coccidiosis in chickens. With the model, we simulate outbreaks of the disease under varying initial contaminations. Heterogeneity in the traits arises stochastically through differences in the dose and frequency of parasites that individuals pick up from the environment. We find that the relationship between the initial contamination and the severity of an outbreak has a non-monotonous ‘wave-like’ pattern. This pattern can be explained by an increased heterogeneity in the host population caused by the infection process at the most severe outbreaks. We conclude that when dealing with these types of infection systems, models that are used to develop or evaluate control measures cannot neglect acquired heterogeneity in the host population traits that interact with the infection process.

scholarly journals Biofilm Formation in Xanthomonas arboricola pv. pruni: Structure and Development

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 546
Author(s):  
Pilar Sabuquillo ◽  
Jaime Cubero
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Environmental Changes ◽  
Nutrient Content ◽  
Infection Process ◽  
Bacterial Attachment ◽  
Key Factors ◽  
Cell Structures ◽  
Microscopy Techniques

Xanthomonasarboricola pv. pruni (Xap) causes bacterial spot of stone fruit and almond, an important plant disease with a high economic impact. Biofilm formation is one of the mechanisms that microbial communities use to adapt to environmental changes and to survive and colonize plants. Herein, biofilm formation by Xap was analyzed on abiotic and biotic surfaces using different microscopy techniques which allowed characterization of the different biofilm stages compared to the planktonic condition. All Xap strains assayed were able to form real biofilms creating organized structures comprised by viable cells. Xap in biofilms differentiated from free-living bacteria forming complex matrix-encased multicellular structures which become surrounded by a network of extracellular polymeric substances (EPS). Moreover, nutrient content of the environment and bacterial growth have been shown as key factors for biofilm formation and its development. Besides, this is the first work where different cell structures involved in bacterial attachment and aggregation have been identified during Xap biofilm progression. Our findings provide insights regarding different aspects of the biofilm formation of Xap which improve our understanding of the bacterial infection process occurred in Prunus spp and that may help in future disease control approaches.

scholarly journals The YadA Protein of Yersinia pseudotuberculosis Mediates High-Efficiency Uptake into Human Cells under Environmental Conditions in Which Invasin Is Repressed

2002 ◽  
Vol 70 (9) ◽  
pp. 4880-4891 ◽  
Author(s):  
Julia Eitel ◽  
Petra Dersch
Keyword(s):  
Extracellular Matrix ◽  
Mammalian Cells ◽  
Yersinia Pseudotuberculosis ◽  
High Efficiency ◽  
Environmental Parameters ◽  
Infection Process ◽  
Nutrient Concentrations ◽  
Integrin Receptors ◽  
Uptake Process ◽  
High Level

ABSTRACT The YadA protein is a major adhesin of Yersinia pseudotuberculosis that promotes tight adhesion to mammalian cells by binding to extracellular matrix proteins. In this study, we first addressed the possibility of competitive interference of YadA and the major invasive factor invasin and found that expression of YadA in the presence of invasin affected neither the export nor the function of invasin in the outer membrane. Furthermore, expression of YadA promoted both bacterial adhesion and high-efficiency invasion entirely independently of invasin. Antibodies against fibronectin and β1 integrins blocked invasion, indicating that invasion occurs via extracellular-matrix-dependent bridging between YadA and the host cell β1 integrin receptors. Inhibitor studies also demonstrated that tyrosine and Ser/Thr kinases, as well as phosphatidylinositol 3-kinase, are involved in the uptake process. Further expression studies revealed that yadA is regulated in response to several environmental parameters, including temperature, ion and nutrient concentrations, and the bacterial growth phase. In complex medium, YadA production was generally repressed but could be induced by addition of Mg2+. Maximal expression of yadA was obtained in exponential-phase cells grown in minimal medium at 37°C, conditions under which the invasin gene is repressed. These results suggest that YadA of Y. pseudotuberculosis constitutes another independent high-level uptake pathway that might complement other cell entry mechanisms (e.g., invasin) at certain sites or stages during the infection process.

scholarly journals A hSCARB2-transgenic mouse model for Coxsackievirus A16 pathogenesis

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yanli Chen ◽  
Heng Li ◽  
Jinxi Yang ◽  
Huiwen Zheng ◽  
Lei Guo ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Scavenger Receptor ◽  
Clinical Signs ◽  
Foot And Mouth Disease ◽  
Infection Process ◽  
Coxsackievirus A16 ◽  
Class B ◽  
Suitable Animal Model ◽  
Limited Host Range ◽  
Brain Tissues

Abstract Background Coxsackievirus A16 (CA16) is one of the neurotropic pathogen that has been associated with severe neurological forms of hand, foot, and mouth disease (HFMD), but its pathogenesis is not yet clear. The limited host range of CA16 make the establishment of a suitable animal model that can recapitulate the neurological pathology observed in human HFMD more difficult. Because the human scavenger receptor class B, member 2 (hSCARB2) is a cellular receptor for CA16, we used transgenic mice bearing human SCARB2 and nasally infected them with CA16 to study the pathogenicity of the virus. Methods Coxsackievirus A16 was administered by intranasal instillation to groups of hSCARB2 transgenic mice and clinical signs were observed. Sampled at different time-points to document and characterize the mode of viral dissemination, pathological change and immune response of CA16 infection. Results Weight loss and virus replication in lung and brain were observed in hSCARB2 mice infected with CA16, indicating that these animals could model the neural infection process. Viral antigens were observed in the alveolar epithelia and brainstem cells. The typical histopathology was interstitial pneumonia with infiltration of significant lymphocytes into the alveolar interstitial in lung and diffuse punctate hemorrhages in the capillaries of the brainstem. In addition, we detected the expression levels of inflammatory cytokines and detected high levels of interleukin IL-1β, IL-6, IL-18, and IFN-γ in nasal mucosa, lungs and brain tissues. Conclusions The hSCARB2-transgenic mice can be productively infected with CA16 via respiratory route and exhibited a clear tropism to lung and brain tissues, which can serve as a model to investigate the pathogenesis of CA16 associated respiratory and neurological disease.

scholarly journals The key amino acids of E protein involved in early flavivirus infection: viral entry

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tao Hu ◽  
Zhen Wu ◽  
Shaoxiong Wu ◽  
Shun Chen ◽  
Anchun Cheng
Keyword(s):  
Amino Acids ◽  
Conformational Changes ◽  
Viral Entry ◽  
Envelope Protein ◽  
Cell Attachment ◽  
Envelope Proteins ◽  
Infection Process ◽  
Early Infection ◽  
Protein Amino Acids ◽  
Α Helix

AbstractFlaviviruses are enveloped viruses that infect multiple hosts. Envelope proteins are the outermost proteins in the structure of flaviviruses and mediate viral infection. Studies indicate that flaviviruses mainly use envelope proteins to bind to cell attachment receptors and endocytic receptors for the entry step. Here, we present current findings regarding key envelope protein amino acids that participate in the flavivirus early infection process. Among these sites, most are located in special positions of the protein structure, such as the α-helix in the stem region and the hinge region between domains I and II, motifs that potentially affect the interaction between different domains. Some of these sites are located in positions involved in conformational changes in envelope proteins. In summary, we summarize and discuss the key envelope protein residues that affect the entry process of flaviviruses, including the process of their discovery and the mechanisms that affect early infection.

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