scholarly journals Protein Diversity and Immune Specificity of Hemocyanin From Shrimp Litopenaeus vannamei

2021 ◽  
Vol 12 ◽  
Author(s):  
Xianliang Zhao ◽  
Jie Qiao ◽  
Pei Zhang ◽  
Zehui Zhang ◽  
Jude Juventus Aweya ◽  
...  
Keyword(s):  
Litopenaeus Vannamei ◽  
Expression Profiles ◽  
Deae Cellulose ◽  
Antibacterial Activities ◽  
Immune Defense ◽  
Innate Immune ◽  
Immune Recognition ◽  
Proteomics Approach ◽  
Sugar Chains ◽  
First Time

Hemocyanin is an important non-specific innate immune defense molecule with phenoloxidase, antiviral, antibacterial, hemolytic, and antitumor activities. To better understand the mechanism of functional diversity, proteomics approach was applied to characterize hemocyanin (HMC) expression profiles from Litopenaeus vannamei. At first, hemocyanin was purified by Sephadex G-100 and DEAE-cellulose (DE-52) columns from shrimp serum, and 34 protein spots were identified as HMC on the 2-DE gels. Furthermore, we found that 9 HMC spots about 75 or 77 kDa were regulated by Streptococcus agalactiae and Vibrio parahaemolyticus infection at 6, 12, and 24 h. In addition, 6 different pathogen-binding HMC fractions, viz., HMC-Mix, HMC-Vp, HMC-Va, HMC-Vf, HMC-Ec, and HMC-Sa, showed different agglutinative and antibacterial activities. Moreover, lectin-blotting analysis showed significant differences in glycosylation level among HMC isomers and bacteria-binding HMC fractions. Particularly, the agglutinative activities of the HMC fractions were almost completely abolished when HMC was deglycosylated by O-glycosidase, which suggest that O-linked sugar chains of HMC played important roles in the innate immune recognition. Our findings demonstrated for the first time that L. vannamei HMC had molecular diversity in protein level, which is closely associated with its ability to recognize diverse pathogens, whereas glycan modification probably contributed to HMC’s diversity and multiple immune activities.

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 Protease-dependent mechanisms of complement evasion by bacterial pathogens

2012 ◽  
Vol 393 (9) ◽  
pp. 873-888 ◽  
Author(s):  
Michal Potempa ◽  
Jan Potempa
Keyword(s):  
Antibacterial Activity ◽  
Complement System ◽  
Antibacterial Activities ◽  
Immune Defense ◽  
Innate Immune ◽  
Human Pathogens ◽  
Human Immune System ◽  
Common Strategy ◽  
Human Immune ◽  
The Complement System

Abstract The human immune system has evolved a variety of mechanisms for the primary task of neutralizing and eliminating microbial intruders. As the first line of defense, the complement system is responsible for rapid recognition and opsonization of bacteria, presentation to phagocytes and bacterial cell killing by direct lysis. All successful human pathogens have mechanisms of circumventing the antibacterial activity of the complement system and escaping this stage of the immune response. One of the ways in which pathogens achieve this is the deployment of proteases. Based on the increasing number of recent publications in this area, it appears that proteolytic inactivation of the antibacterial activities of the complement system is a common strategy of avoiding targeting by this arm of host innate immune defense. In this review, we focus on those bacteria that deploy proteases capable of degrading complement system components into non-functional fragments, thus impairing complement-dependent antibacterial activity and facilitating pathogen survival inside the host.

A typical C-type lectin, perlucin-like protein, is involved in the innate immune defense of whiteleg shrimp Litopenaeus vannamei

2020 ◽  
Vol 103 ◽  
pp. 293-301 ◽  
Author(s):  
Jingxiu Bi ◽  
Mingxiao Ning ◽  
Xiaojun Xie ◽  
Weifeng Fan ◽  
Yanlan Huang ◽  
...  
Keyword(s):  
Litopenaeus Vannamei ◽  
Immune Defense ◽  
Innate Immune ◽  
Innate Immune Defense ◽  
Whiteleg Shrimp

scholarly journals Identification of Natural Target Proteins Indicates Functions of a Serralysin-Type Metalloprotease, PrtA, in Anti-Immune Mechanisms

2009 ◽  
Vol 75 (10) ◽  
pp. 3120-3126 ◽  
Author(s):  
Gabriella Felf�ldi ◽  
Judit Marokh�zi ◽  
Mikl�s K�pir� ◽  
Istv�n Venekei
Keyword(s):  
Immune Defense ◽  
Innate Immune ◽  
Coagulation Cascade ◽  
Sequence Information ◽  
Specific Substrate ◽  
Immune Recognition ◽  
Host Pathogen ◽  
Substrate Proteins

ABSTRACT Serralysins are generally thought to function as pathogenicity factors of bacteria, but so far no hard evidence of this (e.g., specific substrate proteins that are sensitive to the cleavage by these proteases) has been found. We have looked for substrate proteins to a serralysin-type proteinase, PrtA, in a natural host-pathogen molecular interaction system involving Manduca sexta and Photorhabdus luminescens. The exposure in vitro of hemolymph to PrtA digestion resulted in selective cleavage of 16 proteins, provisionally termed PAT (PrtA target) proteins. We could obtain sequence information for nine of these PrtA sensitive proteins, and by searching databases, we could identify six of them. Each has immune-related function involving every aspect of the immune defense: β-1,3 glucan recognition protein 2 (immune recognition), hemocyte aggregation inhibitor protein (HAIP), serine proteinase homolog 3, six serpin-1 variants, including serpin-1I (immune signaling and regulation), and scolexins A and B (coagulation cascade effector function). The functions of the identified PrtA substrate proteins shed new light on a possible participation of a serralysin in the virulence mechanism of a pathogen. Provided these proteins are targets of PrtA in vivo, this might represent, among others, a complex suppressive role on the innate immune response via interference with both the recognition and the elimination of the pathogen during the first, infective stage of the host-pathogen interaction. Our results also raise the possibility that the natural substrate proteins of serralysins of vertebrate pathogens might be found among the components of the innate immune system.

scholarly journals Toll-like receptor 10 is involved in induction of innate immune responses to influenza virus infection

2014 ◽  
Vol 111 (10) ◽  
pp. 3793-3798 ◽  
Author(s):  
Suki M. Y. Lee ◽  
Kin-Hang Kok ◽  
Martial Jaume ◽  
Timothy K. W. Cheung ◽  
Tsz-Fung Yip ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Immune Responses ◽  
Viral Infection ◽  
Influenza Virus Infection ◽  
Immune Defense ◽  
Innate Immune ◽  
Immune Recognition ◽  
Innate Immune Responses ◽  
Infected Cells

Toll-like receptors (TLRs) play key roles in innate immune recognition of pathogen-associated molecular patterns of invading microbes. Among the 10 TLR family members identified in humans, TLR10 remains an orphan receptor without known agonist or function. TLR10 is a pseudogene in mice and mouse models are noninformative in this regard. Using influenza virus infection in primary human peripheral blood monocyte-derived macrophages and a human monocytic cell line, we now provide previously unidentified evidence that TLR10 plays a role in innate immune responses following viral infection. Influenza virus infection increased TLR10 expression and TLR10 contributed to innate immune sensing of viral infection leading to cytokine induction, including proinflammatory cytokines and interferons. TLR10 induction is more pronounced following infection with highly pathogenic avian influenza H5N1 virus compared with a low pathogenic H1N1 virus. Induction of TLR10 by virus infection requires active virus replication and de novo protein synthesis. Culture supernatants of virus-infected cells modestly up-regulate TLR10 expression in nonvirus-infected cells. Signaling via TLR10 was activated by the functional RNA–protein complex of influenza virus leading to robust induction of cytokine expression. Taken together, our findings identify TLR10 as an important innate immune sensor of viral infection and its role in innate immune defense and immunopathology following viral and bacterial pathogens deserves attention.

Chemical Constituents and Antibacterial Activity of Cissus Aralioides.

2020 ◽  
Vol 17 ◽  
Author(s):  
Balogun Olaoye Solomon ◽  
Ajayi Olukayode Solomon ◽  
Owolabi Temitayo Abidemi ◽  
Oladimeji Abdulkarbir Oladele ◽  
Liu Zhiqiang
Keyword(s):  
Plant Extract ◽  
Chemical Constituents ◽  
Ethyl Acetate Fraction ◽  
Antibacterial Activities ◽  
Sub Saharan Africa ◽  
Chromatographic Purification ◽  
Whole Plant ◽  
Sub Saharan ◽  
First Time

: Cissus aralioides is a medicinal plant used in sub-Saharan Africa for treatment of infectious diseases; however the chemical constituents of the plant have not been investigated. Thus, in this study, attempt was made at identifying predominant phytochemical constituents of the plant through chromatographic purification and silylation of the plant extract, and subsequent characterization using spectroscopic and GC-MS techniques. The minimum inhibitory concentration (MICs) for the antibacterial activities of the plant extract, chromatographic fractions and isolated compounds were also examined. Chromatographic purification of the ethyl acetate fraction from the whole plant afforded three compounds: β-sitosterol (1), stigmasterol (2) and friedelin (3). The phytosterols (1 and 2) were obtained together as a mixture. The GC-MS analysis of silylated extract indicated alcohols, fatty acids and sugars as predominant classes, with composition of 24.62, 36.90 and 26.52% respectively. Results of MICs indicated that friedelin and other chromatographic fractions had values (0.0626-1.0 mg/mL) comparable with the standard antibiotics used. Characterization of natural products from C. aralioides is being reported for the first time in this study.

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