China
Africa
Explore chapters and articles related to this topic
Escherichia
Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017
Fimbriae (pili), which are of two kinds, common or conjugative. Common fimbriae (about 100–1000 per cell) comprise mainly an acidic hydrophobic protein called fimbrin and may be divided into seven groups according to the amino acid sequence of their major fimbrin. Conjugative fimbriae (also known as sex pili, usually number one or a few copies per cell) facilitate contact between the donor and recipient bacteria, permitting transfer of DNA during conjugation. Fimbriae are highly antigenic and contain many F antigens.
Gateways of Pathogenic Bacterial Entry into Host Cells—Salmonella
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Balakrishnan Senthilkumar, Duraisamy Senbagam, Chidambaram Prahalathan, Kumarasamy Anbarasu
SipC, one of the components of bacterial translocon, consists of two membrane-spanning domain, s120 amino acid N-terminus and 209 amino acid C-terminus, while the C-terminus extends into the host cytoplasm (Hayward and Koronakis 1999). C-terminal domain of SipC nucleates the gathering of actin filaments, resulting in rapid filament growth from the pointed ends (Hayward and Koronakis 1999). Notably, the SipC C-terminus is also required for translocation of effector protein, suggesting that it modulates both translocon assembly and activities. Chang et al. (2005) has demonstrated that actin nucleation and effector translocation are detachable. A short region proximately next to the second transmembrane domain of SipC (residues 201–220) is responsible for promoting actin nucleation, whereas the C-terminal 88 residues are accountable for effector translocation. Actin filament polymerization has been promoted by a second effector protein, SipA; by sinking the monomer concentration, it is essential for filament assembly by which improving the filament bundling activity of fimbrin, a host protein and influencing nucleation function of SipC (Zhou et al. 1999; McGhie et al. 2001). Besides, SipA binds to assembled filaments and prevents depolymerization (McGhie et al. 2004). Topological analysis indicates that SipA acts as a “molecular staple” using two extended arm domains to truss actin monomers. So, the synergistic activity of SipC and SipA supports the formation of actin filaments in the vicinity to the attached host bacteria, and they become stable over these filaments by host regulatory proteins (Lilic et al. 2003).
MAPK signaling in spermatogenesis and male infertility
Published in Rajender Singh, Molecular Signaling in Spermatogenesis and Male Infertility, 2019
Archana Devi, Bhavana Kushwaha, Gopal Gupta
In mammalian testes, germ cells are anchored to the seminiferous epithelium through different types of anchoring junctions including cell-cell actin-based adhesion junctions, such as testis-specific ectoplasmic specializations and tubulobulbar complexes, cell-cell intermediate filament-based desmosome junctions (6). The testis-specific ectoplasmic specializations (ES) are basically found at the Sertoli-Sertoli and Sertoli–germ cell interface in the seminiferous epithelium and are classified as basal ES (at Sertoli-Sertoli cell interface restricted to BTB coexisting with TJs) and apical ES (at Sertoli-spermatid interface lacking TJs) with morphological similarity (22). The ES is a crucial anchoring device that is prominently involved in the movement of primary germ cells. It is known to provide an additional anchoring function to retain germ cells, specifically spermatids, in the epithelium until spermiation. Multiprotein complexes are found in the ES, namely, the cadherin/catenin, the afadin/nectin/ponsin and the integrin/laminin. Both cadherin/catenin and the nectin/afadin complexes are found at the apical and basal ES regions, though the integrin/laminin complex is restricted to the apical ES region (23). The cadherin/catenin, nectin-2/afadin and β1-integrin/FAK complexes, which are found at the apical ES, interact with cadherins, nectin 2/-3 and laminin-g3, present on the surface of spermatids (24). A group of molecules, including transmembrane adhesion proteins (e.g., adherins, integrins, laminins and nectins, etc.), adaptors (e.g., α-, β- and γ-catenins, afadin, α-actinin, cortactin, fimbrin, paxillin, vinculin, zonula occludens-1 [ZO-1] etc.) and signaling molecules (e.g., protein/lipid kinases and phosphatases) constitute functional adhesion complexes that endow adhesiveness between the two cell types (25). These transmembrane adhesion proteins form a complex with different adaptor proteins in order to interact with the integral membrane protein in the cytoskeleton and facilitate the recruitment of other signaling molecules. Overall, this cytoskeletal complex of proteins supports cell-adhesion and germ cell movement (26,22). The complex dynamic architecture of ES allows it to make fine changes and restructure the ES complex in order to carry out the relay of an extracellular stimulus. Critical events such as the expression level of proteins, phosphorylation status, presence of essential proteins, adaptors, kinases, phosphatases and the actin cytoskeleton drive ES disassembly and reorganization (22).
Plastin 3 down-regulation augments the sensitivity of MDA-MB-231 cells to paclitaxel via the p38 MAPK signalling pathway
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2019
Yan Ma, Wenjia Lai, Minzhi Zhao, Chunyan Yue, Fanghao Shi, Ren Li, Zhiyuan Hu
Herein, we report that another effector molecule, plastin 3 (PLS3), is involved in the regulation of PTX-induced apoptosis. PLS3 (a T-plastin, also named T-fimbrin) functions as filamentous actin (F-actin)-bundling protein to polymerize actin fibres by inhibiting depolymerization [16,17]. PLS3 plays an important role in early cancer diagnosis and therapy [18,19]. Since the 1980s, several studies have reported that PLS3 expression was associated with cellular resistance to chemotherapeutic drugs and cancer progression. Compared with the PLS3 expression level in cisplatin-sensitive human cancer cell lines (e.g. bladder, prostate, and head and neck cancer cell lines), that in their cisplatin-resistant counterparts was increased [20]. The down-regulation of PLS3 expression increased the sensitivity not only to cisplatin in bladder cancer cells but also to VP-16 in human liver cells [21]. These findings indicated that PLS3 may be a novel marker of drug resistance in cancer cells and that the relationship between its expression and drug sensitivity might be due to its involvement in apoptosis. However, the exact details behind the relevance of PLS3 expression to drug therapy and cancer progression are still unknown. In this present study, we sought to identify the role that PLS3 plays in PTX-induced apoptosis in cancer cells. To this end, we conducted PLS3 gene-silencing studies using a TNBC cell line, MDA-MB-231 and compared the responses of the gene-silenced cells under PTX and ABR exposure.
Stenotrophomonas maltophilia biofilm: its role in infectious diseases
Published in Expert Review of Anti-infective Therapy, 2019
Samantha Flores-Treviño, Paola Bocanegra-Ibarias, Adrián Camacho-Ortiz, Rayo Morfín-Otero, Humberto Antonio Salazar-Sesatty, Elvira Garza-González
S. maltophilia fimbriae (SMF-1) mediate S. maltophilia adherence to epithelial cells and participate in early stages of biofilm formation, as well as agglutination in species-specific red blood cells [21]. SMF-1 are peritrichous semiflexible fimbriae of 5–7 nm width composed of a 17 kDa fimbrin subunit [21], which includes the SMF-1 fimbrial operon [22]. The fimbriae encoding gene smf-1 was detected in 23% of clinical S. maltophilia strains and 42% of environmental strains. Only isolates harboring the smf-1 gene were able to produce biofilm [23]. Both SMF-1 and flagella are involved in promoting intimate attachment to the surface, thus assisting biofilm formation [7] and respiratory tract colonization by S. maltophilia in CF patients [24].
Methyl and methylene vibrations response in amino acids of typical proteins in water solution under high-frequency electromagnetic field
Published in Electromagnetic Biology and Medicine, 2019
Emanuele Calabrò, Salvatore Magazù
The role of methylene (CH2) group in proteins is important, as well. Particularly in full-length proteins, the CH2 molecule determines distinct functions of fimbrin-plastins (Klein et al. 2004). It was found that CH2 acts as the main regulator in the modulation of conformational plasticity of fimbrins-plastins, regulating the interaction of CH domain-containing proteins with F-actin (Zhang, Chang, and Zhang 2016).