scholarly journals Involvement of Various Enzymes in the Physiology and Pathogenesis of Streptococcus suis

2020 ◽  
Vol 7 (4) ◽  
pp. 143
Author(s):  
Chengkun Zheng ◽  
Man Wei ◽  
Mengdie Jia ◽  
ManMan Cao

Streptococcus suis causes severe infections in both swine and humans, making it a serious threat to the swine industry and public health. Insight into the physiology and pathogenesis of S. suis undoubtedly contributes to the control of its infection. During the infection process, a wide variety of virulence factors enable S. suis to colonize, invade, and spread in the host, thus causing localized infections and/or systemic diseases. Enzymes catalyze almost all aspects of metabolism in living organisms. Numerous enzymes have been characterized in extensive detail in S. suis, and have shown to be involved in the pathogenesis and/or physiology of this pathogen. In this review, we describe the progress in the study of some representative enzymes in S. suis, such as ATPases, immunoglobulin-degrading enzymes, and eukaryote-like serine/threonine kinase and phosphatase, and we highlight the important role of various enzymes in the physiology and pathogenesis of this pathogen. The controversies about the current understanding of certain enzymes are also discussed here. Additionally, we provide suggestions about future directions in the study of enzymes in S. suis.

Author(s):  
Amelia U. Schirmer ◽  
Lucy M. Driver ◽  
Megan T. Zhao ◽  
Carrow I. Wells ◽  
Julie E. Pickett ◽  
...  

1997 ◽  
Vol 45 (1) ◽  
pp. 107-118 ◽  
Author(s):  
André Nadeau ◽  
Gilles Grondin ◽  
Richard Blouin

ZPK is a recently described protein serine/threonine kinase that has been originally identified from a human teratocarcinoma cell line by the polymerase chain reaction and whose function in signal transduction has not yet been elucidated. To investigate the potential role of this protein kinase in developmental processes, we have analyzed the spatial and temporal patterns of expression of the ZPK gene in mouse embryos of different gestational ages. Northern blot analysis revealed a single mRNA species of about 3.5 KB from Day 11 of gestation onwards. In situ hybridization studies demonstrated strong expression of ZPK mRNA in brain and in a variety of embryonic organs that rely on epithelio-mesenchymal interactions for their development, including skin, intestine, pancreas, and kidney. In these tissues, the ZPK mRNA was localized primarily in areas composed of specific types of differentiating cells, and this expression appeared to be upregulated at a time concomitant with the onset of terminal differentiation. Taken together, these observations raise the possibility that the ZPK gene product is involved in the establishment and/or maintenance of a fully cytodifferentiated state in a variety of cell lineages.


Author(s):  
Novriantika Lestari

Liver fibrosis is a reversible response to a wound healing with marked accumulation of extracellular matrix which caused by injury to the liver. Liver fibrosis can be caused by various factors including alcohol and non-alcohol steatohepatitis. The process of fibrosis serves to localize the inflammation during chronic exposure. The hepatic stem cell (HSC) has a key role in the pathogenesis of liver fibrosis. The HSC activation is characterized by increased profibrogenic mediators including members of the TGF-? superfamily. In order to enable signal transduction, the mediator needs to bind to its receptors. The serine/ threonine kinase receptor is a receptor that binds to the TGF-? superfamily ligand, including TGF-?, BMP, activin and other mediators. The ligand receptor-binding activity will stimulate signal transduction that will translocate into the nucleus and phosphorylate various transcription factors that play a role in cell proliferation, differentiation, or apoptosis. There is currently no standard therapy for liver fibrosis. Based on the central role of the serine/ threonine kinase receptor in the pathogenesis of liver fibrosis, it is thought that the use of serine/ threonine kinase inhibitors is a promising therapy.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Anahita Rahmani ◽  
Danial Kheradmand ◽  
Peyman Keyhanvar ◽  
Alireza Shoae-Hassani ◽  
Amir Darbandi-Azar

Fluoxetine (FLX) is a selective serotonin reuptake inhibitor (SSRI). Its action is possibly through an increase in neural cell survival. The mechanism of improved survival rate of neurons by FLX may relate to the overexpression of some kinases such as Akt protein. Akt1 (a serine/threonine kinase) plays a key role in the modulation of cell proliferation and survival. Our study evaluated the effects of FLX on mesenchymal stem cell (MSC) fate and Akt1 phosphorylation levels in MSCs. Evaluation tests included reverse transcriptase polymerase chain reaction, western blot, and immunocytochemistry assays. Nestin, MAP-2, andβ-tubulin were detected after neurogenesis as neural markers. TenμM of FLX upregulated phosphorylation of Akt1 protein in induced hEnSC significantly. Also FLX did increase viability of these MSCs. Continuous FLX treatment after neurogenesis elevated the survival rate of differentiated neural cells probably by enhanced induction of Akt1 phosphorylation. This study addresses a novel role of FLX in neurogenesis and differentiated neural cell survival that may contribute to explaining the therapeutic action of fluoxetine in regenerative pharmacology.


2005 ◽  
Vol 3 (2) ◽  
pp. 198-205
Author(s):  
Margaret von Mehren

Medical management of soft tissue sarcomas (STS) has been restricted by the limited availability of active drugs. A plethora of new oncologic agents are now available, many of which have specific therapeutic targets. Gemcitabine and docetaxel is a combination of drugs that have limited single-agent activity. Yondelis, a novel chemotherapeutic that binds DNA and functions partially by inhibiting transcription, is being tested alone and in combination with doxorubicin. Inhibitors of mTOR, a serine/threonine kinase that regulates cell cycle activation and cell growth, are also being tested. Growth factor receptor inhibitors are being evaluated in a variety of sarcomas that have been found to express the targets. In addition, a variety of agents are being assessed in gastrointestinal stromal tumors (GIST). Single agents and agents combined with imatinib are being tested in imatinib-refractory and in metastatic GIST. The increased use of targeted agents underscores the need for understanding sarcoma biology.


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