• Title/Summary/Keyword: cell infection

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Signaling Pathways Controlling Microglia Chemotaxis

  • Fan, Yang;Xie, Lirui;Chung, Chang Y.
    • Molecules and Cells
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    • v.40 no.3
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    • pp.163-168
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    • 2017
  • Microglia are the primary resident immune cells of the central nervous system (CNS). They are the first line of defense of the brain's innate immune response against infection, injury, and diseases. Microglia respond to extracellular signals and engulf unwanted neuronal debris by phagocytosis, thereby maintaining normal cellular homeostasis in the CNS. Pathological stimuli such as neuronal injury induce transformation and activation of resting microglia with ramified morphology into a motile amoeboid form and activated microglia chemotax toward lesion site. This review outlines the current research on microglial activation and chemotaxis.

AN EXPERIMENTAL STUDY ON THE EFFECT OF ALCOHOL INJECTION IN RAT ORAL MUCOSA (알콜(Alcohol)주사가 구강조직에 미치는 영향에 관한 실험적 연구)

  • Min, Byong-Il
    • The Journal of the Korean dental association
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    • v.15 no.12
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    • pp.957-962
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    • 1977
  • The author has observed the tissue reaction of the absolute alcohol infection of rat oral mucosa. 0.5ml absolute alcohol was injected subcutaneously on the mucobuccal fold of rat. And the rats were sacrifieced at intervals of one day, 3rd, 1 week, 2 week and 4 week after alcohol injection. The microscopic tissue sections were made and stained with hematoxylin and eosin. The results were are as follows; 1. Degeneration and shrinkage of fibroblasts and coagulative necrosis were observed one day to and three day after alcohol injection. 2. Although coagulative necrosis and tissue degeneration occurred, the inflammatory infiltration was not prominent especially there were scarcely any polymorphonuclear leukocytes in that field. 3. Granulation tissue with moderate small round cell infiltration were replaced the necrotic area at one week after injection and the fibroblast proliferate into the granulation tissue at two week group. 4. At four week after injection, the damaged area recovered by fibroblastic proliferation and collage formation, but there were

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Genetic and Environmental Control of Salmonella Invasion

  • Altier, Craig
    • Journal of Microbiology
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    • v.43 no.spc1
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    • pp.85-92
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    • 2005
  • An early step in the pathogenesis of non-typhoidal Salmonella species is the ability to penetrate the intestinal epithelial monolayer. This process of cell invasion requires the production and transport of secreted effector proteins by a type III secretion apparatus encoded in Salmonella pathogenicity island I (SPI-1). The control of invasion involves a number of genetic regulators and environmental stimuli in complex relationships. SPI-1 itself encodes several transcriptional regulators (HilA, HilD, HilC, and InvF) with overlapping sets of target genes. These regulators are, in turn, controlled by both positive and regulators outside SPI-1, including the two-component regulators BarA/SirA and PhoP/Q, and the csr post-transcriptional control system. Additionally, several environmental conditions are known to regulate invasion, including pH, osmolarity, oxygen tension, bile, $Mg^{2+}$ concentration, and short chain fatty acids. This review will discuss the current understanding of invasion control, with emphasis on the interaction of environmental factors with genetic regulators that leads to productive infection.

CD1b in immature dendritic cells acquires increased phagocytotic function (수지상세포의 CD1b 분자와 포식작용의 증가)

  • Liew, Hyunjeong
    • Korean Journal of Microbiology
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    • v.54 no.3
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    • pp.222-227
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    • 2018
  • Mycobacterium tuberculosis (MTB)-originated lipid antigen is presented on the antigen-presenting cell surface with CD1b. When monocyte-derived dendritic cells phagocytosed MTB H37Rv (Multiplicity of infection 10, infectivity: 46.89%), the CD1b expression level decreased slowly. Since this was just a live MTB-mediated phenomenon, it was not detected from heat-killed MTB or mycolic acid, which is a unique antigen of MTB. We confirmed that the phosphorylation of CD1b molecules using 2D electrophoresis with staining could phosphorylate and induce the presentation of the lipid antigen using the phagocytosis assay.

Investigation on Lipopolysaccharide Activated Microglia by Phosphoproteomics and Phosphoinositide Lipidomics

  • Kim, Young Jun;Kim, Hackyoung;Noh, Kwangmo
    • Mass Spectrometry Letters
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    • v.5 no.3
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    • pp.70-78
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    • 2014
  • Microglia are the confined immune cells of the central nervous system (CNS). In response to injury or infection, microglia readily become activated and release proinflammatory mediators that are believed to contribute to microglia-mediated neurodegeneration. In the present study, inflammation was induced in the immortalized murine microglial cell line BV-2 by lipopolysaccharide (LPS) treatment. We firstly performed phosphoproteomics analysis and phosphoinositide lipidomics analysis with LPS activated microglia in order to compare phosphorylation patterns in active and inactive microglia and to detect the pattern of changes in phosphoinositide regulation upon activation of microglia. Mass spectrometry analysis of the phosphoproteome of the LPS treatment group compared to that of the untreated control group revealed a notable increase in the diversity of cellular phosphorylation upon LPS treatment. Additionally, a lipidomics analysis detected significant increases in the amounts of phosphoinositide species in the LPS treatment. This investigation could provide an insight for understanding molecular mechanisms underlying microglia-mediated neurodegenerative diseases.

Nitrogen Sources Inhibit Biofilm Formation by Xanthomonas oryzae pv. oryzae

  • Ham, Youngseok;Kim, Tae-Jong
    • Journal of Microbiology and Biotechnology
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    • v.28 no.12
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    • pp.2071-2078
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    • 2018
  • Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight, which results in severe economic damage to rice farms. Xoo produces biofilms for pathogenesis and survival both inside and outside the host. Biofilms, which are important virulence factors, play a key role in causing the symptoms of Xoo infection. In the present study, we investigated the nutritional conditions for biofilm formation by Xoo. Although Xoo biofilm formation may be initiated by interactions with the host, Xoo biofilm cannot mature without the support of favorable nutritional conditions. Nitrogen sources inhibited Xoo biofilm formation by overwhelming the positive effect that cell growth has on it. However, limited nutrients with low amino acid concentration supported biofilm formation by Xoo in the xylem sap rather than in the phloem sap of rice.

Antimicrobial and Immunomodulatory Effects of Bifidobacterium Strains: A Review

  • Lim, Hyun Jung;Shin, Hea Soon
    • Journal of Microbiology and Biotechnology
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    • v.30 no.12
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    • pp.1793-1800
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    • 2020
  • Bifidobacterium strains can provide several health benefits, such as antimicrobial and immunomodulatory effects. Some strains inhibit growth or cell adhesion of pathogenic bacteria, including multidrug-resistant bacteria, and their antibacterial activity can be intensified when combined with certain antibiotics. In addition, some strains of bifidobacteria reduce viral infectivity, leading to less epithelial damage of intestinal tissue, lowering the virus shedding titer, and controlling the release of antiviral substances. Furthermore, bifidobacteria can modulate the immune system by increasing immunoglobulins, and inducing or reducing pro- or anti-inflammatory cytokines, respectively. In particular, these anti-inflammatory effects are helpful in the treatment of patients who are already suffering from infection or inflammatory diseases. This review summarizes the antimicrobial effects and mechanisms, and immunomodulatory effects of Bifidobacterium strains, suggesting the potential of bifidobacteria as an alternative or complementary treatment option.

Exploring Staphylococcus aureus Virulence Factors; Special Emphasis on Staphyloxanthin

  • Yehia, Fatma Al-zahraa A.;Yousef, Nehal;Askoura, Momen
    • Microbiology and Biotechnology Letters
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    • v.49 no.4
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    • pp.467-477
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    • 2021
  • Staphylococcus aureus is a well-known pathogen that can cause diseases in humans. It can cause both mild superficial skin infections and serious deep tissue infections, including pneumonia, osteomyelitis, and infective endocarditis. To establish host infection, S. aureus manages a complex regulatory network to control virulence factor production in both temporal and host locations. Among these virulence factors, staphyloxanthin, a carotenoid pigment, has been shown to play a leading role in S. aureus pathogenesis. In addition, staphyloxanthin provides integrity to the bacterial cell membrane and limits host oxidative defense mechanisms. The overwhelming rise of Staphylococcus resistance to routinely used antibiotics has necessitated the development of novel anti-virulence agents to overcome this resistance. This review presents an overview of the chief virulence determinants in S. aureus. More attention will be paid to staphyloxanthin, which could be a possible target for anti-virulence agents.

A Study on the Preparation of 5(6)-Carboxyflurescein-supported Phospholipid Liposomes and Evaluation of Bacterial Sensing Ability (5(6)-Carboxyflurescein을 담지한 인지질 리포좀의 제조 및 박테리아 센싱 능력 평가에 대한 연구)

  • Han, Minho;Jeon, Jaewoo;Lee, Junyoung;Shin, Eunsuk;Kim, Woojin;Kim, Samsoo
    • Textile Coloration and Finishing
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    • v.33 no.4
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    • pp.338-347
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    • 2021
  • In the case of occlusive dressings currently used in dressings for burn treatment, it is impossible to confirm the replacement time, so replacement is delayed, resulting in additional infection. To solve this problem, liposomes capable of bacterial sensing were prepared using 5(6)-Carboxyfluorescein, Phosphatidylcholine, 1,2-Dipalmitoyl-sn-glycero-3-phosphocholine, Cholesterol, and 10,12-Tricosadiynoic acid. In this study, evaluation of changes in drug encapsulation rate in liposomes according to changes in three types of phosphatidylcholine phospholipids during liposome production, high-performance phosphatidylcholine phospholipids selected through vesicle size analysis, low and high temperature stability evaluation, bacterial sensitization ability evaluation, animals cell responses were assessed.