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1.
J Immunol ; 207(7): 1735-1746, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34462314

RESUMO

The house dust mite is the most common cause of allergic diseases, and TLR4 acts as an overarching receptor for allergic responses. This study aimed to identify novel allergen binding to TLR4 in house dust mites and unveil its unique role in allergic responses. Der p 38 was purified and characterized by liquid chromatography tandem mass spectrometry-based peptide mapping. Biolayer interferometry and structure modeling unveiled TLR4-binding activity and the structure of recombinant Der p 38. The allergenicity of Der p 38 was confirmed by a skin prick test, and basophil activation and dot blot assays. The skin prick test identified 24 out of 45 allergic subjects (53.3%) as Der p 38+ subjects. Der p 38-augmented CD203c expression was noted in the basophils of Der p 38+ allergic subjects. In animal experiments with wild-type and TLR4 knockout BALB/c mice, Der p 38 administration induced the infiltration of neutrophils as well as eosinophils and exhibited clinical features similar to asthma via TLR4 activation. Persistent Der p 38 administration induced severe neutrophil inflammation. Der p 38 directly suppressed the apoptosis of allergic neutrophils and eosinophils, and enhanced cytokine production in human bronchial epithelial cells, inhibiting neutrophil apoptosis. The mechanisms involved TLR4, LYN, PI3K, AKT, ERK, and NF-κB. These findings may contribute to a deep understanding of Der p 38 as a bridge allergen between eosinophilic and neutrophilic inflammation in the pathogenic mechanisms of allergy.


Assuntos
Antígenos de Dermatophagoides/imunologia , Eosinófilos/imunologia , Hipersensibilidade/imunologia , Neutrófilos/fisiologia , Mucosa Respiratória/imunologia , Animais , Antígenos de Dermatophagoides/isolamento & purificação , Células Cultivadas , Modelos Animais de Doenças , Mapeamento de Epitopos , Feminino , Humanos , Imunomodulação , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Ativação de Neutrófilo , Ligação Proteica , Transdução de Sinais , Testes Cutâneos , Receptor 4 Toll-Like/metabolismo
2.
Int J Mol Sci ; 22(16)2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34445142

RESUMO

It is difficult to treat allergic diseases including asthma completely because its pathogenesis remains unclear. House dust mite (HDM) is a critical allergen and Toll-like receptor (TLR) 4 is a member of the toll-like receptor family, which plays an important role in allergic diseases. The purpose of this study was to characterize a novel allergen, Der f 38 binding to TLR4, and unveil its role as an inducer of allergy. Der f 38 expression was detected in the body and feces of Dermatophagoides farinae (DF). Electron microscopy revealed that it was located in the granule layer, the epithelium layer, and microvilli of the posterior midgut. The skin prick test showed that 60% of allergic subjects were Der f 38-positive. Der f 38 enhanced surface 203c expression in basophils of Der f 38-positive allergic subjects. By analysis of the model structure of Der p 38, the expected epitope sites are exposed on the exterior side. In animal experiments, Der f 38 triggered an infiltration of inflammatory cells. Intranasal (IN) administration of Der f 38 increased neutrophils in the lung. Intraperitoneal (IP) and IN injections of Der f 38 induced both eosinophils and neutrophils. Increased total IgE level and histopathological features were found in BALB/c mice treated with Der f 38 by IP and IN injections. TLR4 knockout (KO) BALB/c mice exhibited less inflammation and IgE level in the sera compared to wild type (WT) mice. Der f 38 directly binds to TLR4 using biolayer interferometry. Der f 38 suppressed the apoptosis of neutrophils and eosinophils by downregulating proteins in the proapoptotic pathway including caspase 9, caspase 3, and BAX and upregulating proteins in the anti-apoptotic pathway including BCL-2 and MCL-1. These findings might shed light on the pathogenic mechanisms of allergy to HDM.


Assuntos
Alérgenos/imunologia , Antígenos de Dermatophagoides/imunologia , Proteínas de Artrópodes/imunologia , Dermatophagoides farinae/imunologia , Hipersensibilidade/imunologia , Ligação Proteica/imunologia , Receptor 4 Toll-Like/imunologia , Sequência de Aminoácidos , Animais , Epitopos/imunologia , Feminino , Humanos , Imunoglobulina E/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Pyroglyphidae/metabolismo , Testes Cutâneos/métodos
3.
J Environ Manage ; 297: 113268, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34280865

RESUMO

The fossil fuel utilization adversely affected the environmental health due to the rising emission levels of greenhouse gases. Consequently, the challenges of climate change loaded great stress on renewable energy sources. It is noted that extreme consumption of fossil fuels increased the earth temperature by 1.9 °C that adversely influenced the life and biodiversity. Biorefinery is the sustainable process for the production of biofuels and other bio-products from biomass feedstock using different conversion technologies. Biofuel is an important component of renewable energy sources contributing to overall carbon-neutral energy system. Studies reported that on global scale, over 90% of petroleum goods could be produced from renewable resources by 2023, whereas, 33% chemicals, and 50% of the pharmaceutical market share is also expected to be bio-based. This study details the brief review of operation, development, application, limitations, future perspectives, circular bioeconomy, and life cycle assessment of biorefinery. The economic and environmental aspects of biofuels and biorefineries are briefly discussed. Lastly, considering the present challenges, the future perspectives of biofuels and biorefineries are highlighted.


Assuntos
Biocombustíveis , Carbono , Biomassa , Combustíveis Fósseis
4.
Int J Med Sci ; 17(4): 498-509, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32174780

RESUMO

S100A8 and S100A9 are important proteins in the pathogenesis of allergy. Asthma is an allergic lung disease, characterized by bronchial inflammation due to leukocytes, bronchoconstriction, and allergen-specific IgE. In this study, we examined the role of S100A8 and S100A9 in the interaction of cytokine release from bronchial epithelial cells, with constitutive apoptosis of neutrophils. S100A8 and S100A9 induce increased secretion of neutrophil survival cytokines such as MCP-1, IL-6 and IL-8. This secretion is suppressed by TLR4 inhibitor), LY294002, AKT inhibitor, PD98059, SB202190, SP600125, and BAY-11-7085. S100A8 and S100A9 also induce the phosphorylation of AKT, ERK, p38 MAPK and JNK, and activation of NF-κB, which were blocked after exposure to TLR4i, LY294002, AKTi, PD98059, SB202190 or SP600125. Furthermore, supernatants collected from bronchial epithelial cells after S100A8 and S100A9 stimulation suppressed the apoptosis of normal and asthmatic neutrophils. These inhibitory mechanisms are involved in suppression of caspase 9 and caspase 3 activation, and BAX expression. The degradation of MCL-1 and BCL-2 was also blocked by S100A8 and S100A9 stimulation. Essentially, neutrophil apoptosis was blocked by co-culture of normal and asthmatic neutrophils with BEAS-2B cells in the presence of S100A8 and S100A9. These findings will enable elucidation of asthma pathogenesis.


Assuntos
Asma/metabolismo , Calgranulina A/uso terapêutico , Calgranulina B/farmacologia , Apoptose/efeitos dos fármacos , Western Blotting , Caspase 3/metabolismo , Caspase 9/metabolismo , Linhagem Celular , Citocinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Eosinófilos/efeitos dos fármacos , Eosinófilos/metabolismo , Humanos , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Receptor 4 Toll-Like/metabolismo
5.
J Environ Manage ; 270: 110909, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32721343

RESUMO

This review summarizes the recent development and studies of anaerobic membrane bioreactor (AnMBR) to control fouling issues. AnMBR is an emerging waste water treatment technology mainly because of its low sludge residual, high volumetric organic removal rate, complete liquid-solid separation, better effluent quality, efficient resource recovery and the small footprint. This paper surveys the fundamental aspects of AnMBRs, including its applications, membrane configurations, and recent progress for enhanced reactor performance. Furthermore, the membrane fouling, a major restriction in the practical application of AnMBR, its mechanism and antifouling strategies like membrane cleaning, quorum quenching, ultrasonic treatment, membrane modifications, and antifouling agents are briefly discussed. Based on the review, the key issues that require urgent attention to facilitate large scale and integrated application of AnMBR technology are identified and future research perspectives relating to the prevalent issues are proposed.


Assuntos
Reatores Biológicos , Purificação da Água , Anaerobiose , Membranas Artificiais , Esgotos , Eliminação de Resíduos Líquidos , Águas Residuárias
6.
Int J Med Sci ; 16(8): 1116-1122, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31523174

RESUMO

This study investigated the anti-allergic effect of Poncirus trifoliata (L.) Raf. (PT) on human keratinocytic HaCaT cells in vitro and on 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis-like lesions in vivo. The release of TARC, MCP-1, IL-6 and IL-8 is increased by IFN-γ and TNF-α in HaCaT cells, and PT extract suppressed the increased production of TARC, MCP-1, IL-6, and IL-8. PT extract recovered the expression of filaggrin decreased by IFN-γ and TNF-α. in vivo experiment, PT administration decreased the skin severity score, thickening of the epidermis, movement of inflammatory cells into the dermis, and serum IgE level as compared to DNCB treatment. Moreover, the decrease of filaggrin and loricrin induced by DNCB treatment was recovered by PT administration. The levels of IL-4, IL-5, IL-13 and eotaxin in mouse splenocytes increased after treatment with concanavalin A, and the secretions of IL-4, IL-5, IL-13 and eotaxin were lower in the PT-treated group than in the DNCB group. These findings may indicate that PT is useful in drug development for the treatment of AD.


Assuntos
Dermatite Atópica/tratamento farmacológico , Queratinócitos/efeitos dos fármacos , Queratinócitos/patologia , Extratos Vegetais/farmacologia , Poncirus/química , Animais , Linhagem Celular , Quimiocina CCL11/metabolismo , Citocinas/metabolismo , Dermatite Atópica/induzido quimicamente , Dermatite Atópica/patologia , Dinitroclorobenzeno/toxicidade , Feminino , Proteínas Filagrinas , Humanos , Imunoglobulina E/sangue , Interferon gama/farmacologia , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos , Proteínas S100/metabolismo , Baço/citologia , Baço/metabolismo , Fator de Necrose Tumoral alfa/farmacologia
7.
Int J Med Sci ; 16(12): 1604-1613, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31839748

RESUMO

Chaenomeles sinensis Koehne (CS) has been used in a traditional oriental medicine for treating throat diseases, anaphylaxis, viral infection, and inflammation. This study investigated the underlying mechanism of anti-allergic effect of CS. Leaves of CS plants were dried, powdered, and then underwent extraction with DMSO. Both ELISA and western blotting were performed to evaluate cytokine concentration and the expression and activation of filaggrin and JNK. Five-week-old female NC/Nga mice were used as an AD-like mouse model by treating them with 2,4-dinitrochlorobenzene (DNCB). The secretion of TARC, MCP-1, and IL-8 is increased by TNF-α and IFN-γ in HaCaT cells, and CS extract inhibited the increased production of TARC, MCP-1, and IL-8. TNF-α and IFN-γ suppressed filaggrin expression by activating JNK. CS extract recovered the expression of filaggrin decreased by TNF-α and IFN-γ by blocking the activation of JNK. In vivo experiment, CS administration reduced thickening of the epidermis and infiltration of inflammatory cells into the dermis as compared to DNCB treatment. Moreover, the decrease of filaggrin expression due to DNCB treatment was recovered by CS administration. The serum IgE level was decreased by CS treatment. The levels of IL-4, IL-5, IL-13 and eotaxin in mouse splenocytes increased after treatment with concanavalin A, and the secretions of IL-4, IL-5, IL-13 and eotaxin were lower in the CS-treated group than in the DNCB group. These results may contribute to the development of a CS-based drug for the treatment of atopic dermatitis.


Assuntos
Citocinas/genética , Dermatite Atópica/tratamento farmacológico , Proteínas de Filamentos Intermediários/genética , Rosaceae/química , Animais , Dermatite Atópica/genética , Dermatite Atópica/patologia , Dinitroclorobenzeno/farmacologia , Modelos Animais de Doenças , Proteínas Filagrinas , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Inflamação/tratamento farmacológico , Inflamação/genética , Inflamação/patologia , Interferon gama/genética , Queratinócitos/efeitos dos fármacos , Camundongos , Extratos Vegetais/química , Extratos Vegetais/farmacologia
8.
Antibiotics (Basel) ; 13(2)2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38391498

RESUMO

Staphylococcus aureus sequence type (ST) 398 is a lineage affecting both humans and livestock worldwide. However, the mechanisms underlying its clonal evolution are still not clearly elucidated. We applied whole-genome sequencing (WGS) typing to 45 S. aureus strains from China and Canada between 2005 and 2014, in order to gain insight into their evolutionary pathway. Based on WGS phylogenetic analysis, 42 isolates were assigned to the human-associated clade (I/II-GOI) and 3 isolates to livestock-associated clade (IIa). Phylogeny of ϕSa3 sequences revealed five phage groups (Groups 1-5), with Group 1 carrying ϕSa3-Group 1 (ϕSa3-G1), Group 2 carrying ϕSa3-G2, Group 3 carrying ϕSa3-G3, Group 4 carrying ϕSa3-G4 and Group 5 lacking ϕSa3. ϕSa3-G1 was only found in strains that accounted for the most ancestral human clade I, while ϕSa3-G2, ϕSa3-G3 and ϕSa3-G4 were found restricted to sublineages within clade II-GOI. Some isolates of clade II-GOI were also found to be ϕSa3-negative or resistant to methicillin which are unusual characteristics for human-adapted isolates. This study demonstrated a strong association between phylogenetic grouping and phage type, suggesting an important role of ϕSa3 prophage in the evolution of human-adapted ST398 subclones. In addition, our results suggest that this subclone slowly began to adapt to animal hosts by losing ϕSa3 and acquiring methicillin resistance, which was observed in some strains of human-associated clade II-GOI, an intermediate human to livestock transmission clade.

9.
Brain Sci ; 13(5)2023 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-37239189

RESUMO

Stroke is the fourth leading cause of mortality and is estimated to be one of the major reasons for long-lasting disability worldwide. There are limited studies that describe the application of physical therapy interventions to prevent disabilities in stroke survivors and promote recovery after a stroke. In this review, we have described a wide range of interventions based on impairments, activity limitations, and goals in recovery during different stages of a stroke. This article mainly focuses on stroke rehabilitation tactics, including those for sensory function impairments, motor learning programs, hemianopia and unilateral neglect, flexibility and joint integrity, strength training, hypertonicity, postural control, and gait training. We conclude that, aside from medicine, stroke rehabilitation must address specific functional limitations to allow for group activities and superior use of a hemiparetic extremity. Medical doctors are often surprised by the variety of physiotherapeutic techniques available; they are unfamiliar with the approaches of researchers such as Bobath, Coulter, and Brunnstrom, among others, as well as the scientific reasoning behind these techniques.

10.
Children (Basel) ; 10(5)2023 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-37238390

RESUMO

Spasticity is a common issue among children, especially those with bilateral spastic cerebral palsy (CP). Selective dorsal rhizotomy (SDR) is a surgical procedure that is often used to decrease lower limb rigidity, alongside other treatment options such as intrathecal medication, peripheral nerve surgery, and deep brain stimulation (DBS). The objective of these therapies is to improve the standard of living for young individuals. This article intends to explain the motor deficits observed in spastic diplegia and a rehabilitation program using physical therapy after SDR. The information can help with counseling parents about the prognosis and developing a clinical treatment plan. The article presents a case study of a 12-year-old girl who recently underwent L3, L4, and L5 nerve root rhizotomy in the physical therapy department. It highlights the importance of long-term physical therapy follow-up and orthotic usage in the management of spastic diplegia.

11.
Adv Colloid Interface Sci ; 306: 102718, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35714572

RESUMO

This review discusses the classification, characteristics, and applications of biosurfactants. The biosynthesis pathways for different classes of biosurfactants are reviewed. An in-depth analysis of reported research is carried out emphasizing the synthetic pathways, culture media compositions, and influencing factors on production yield of biosurfactants. The environmental, pharmaceutical, industrial, and other applications of biosurfactants are discussed in detail. A special attention is given to the biosurfactants application in combating the pandemic COVID-19. It is found that biosurfactant production from waste materials can play a significant role in enhancing circular bioeconomy and environmental sustainability. This review also details the life cycle assessment methodologies for the production and applications of biosurfactants. Finally, the current status and limitations of biosurfactant research are discussed and the potential areas are highlighted for future research and development. This review will be helpful in selecting the best available technology for biosynthesis and application of particular biosurfactant under specific conditions.


Assuntos
COVID-19 , Tensoativos , Humanos , Tensoativos/metabolismo
12.
Front Immunol ; 12: 646316, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34691014

RESUMO

Atopic dermatitis (AD) is a chronic relapsing pruritic disease encompassing skin inflammation and barrier dysfunction. House dust mites are key allergens that augment the development of atopic dermatitis. We aimed to investigate the pathogenic mechanism of AD due to Der p 38, recently identified by us. The frequency of IgE reactivity to Der p 38 in AD subjects was 52.6% (10/19) in the skin prick test and 57.9% (11/19) in the dot blot assay. In human keratinocyte HaCaT cells, Der p 38 triggered the impairment of filaggrin expression and induced pro-inflammatory cytokines such as IL-6, IL-8 and MCP-1 through TLR4, PI3K, AKT, c-Jun N-terminal kinase (JNK) and NF-κB pathway. Supernatants from Der p 38-treated cells blocked filaggrin expression and neutrophil apoptosis. The anti-apoptotic effect of the Der p 38-released molecules on neutrophils was accomplished by inhibition of the caspase 9/3 pathway, and by increased MCL-1 expression and BCL-2/BAX expression ratio. In C57BL/6 wild type (WT) mice, Der p 38 induced a dose-dependent increase of AD-like skin lesions, with enhanced expressions of total and Der p 38-specific IgE. Der p 38 also diminished the expressions of skin barrier proteins and induced JNK activation. However, the AD-like features following cutaneous Der p 38 exposure were observed to be reduced in the TLR4 knockout (KO) group, as compared to the WT group. Skin infiltration of neutrophils, eosinophils and mast cells was increased in the WT mice, but was not portrayed in the TLR4 KO mice. These findings indicate that Der p 38 is a novel mite allergen that triggers AD by lowering skin barrier proteins and increasing inflammatory cells. Results of this study have thereby paved the way to unveil the pathogenic mechanisms of AD.


Assuntos
Antígenos de Dermatophagoides/imunologia , Proteínas de Artrópodes/imunologia , Dermatite Atópica/imunologia , Dermatophagoides farinae/imunologia , Queratinócitos/imunologia , Pele/imunologia , Receptor 4 Toll-Like/metabolismo , Adulto , Animais , Antígenos de Dermatophagoides/genética , Antígenos de Dermatophagoides/metabolismo , Apoptose , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Artrópodes/genética , Proteínas de Artrópodes/metabolismo , Citocinas/metabolismo , Dermatite Atópica/genética , Dermatite Atópica/metabolismo , Dermatite Atópica/patologia , Dermatophagoides farinae/genética , Dermatophagoides farinae/metabolismo , Modelos Animais de Doenças , Eosinófilos/imunologia , Eosinófilos/metabolismo , Eosinófilos/patologia , Feminino , Proteínas Filagrinas/metabolismo , Células HaCaT , Humanos , Imunoglobulina E/sangue , Mediadores da Inflamação/metabolismo , Queratinócitos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Pessoa de Meia-Idade , Neutrófilos/imunologia , Neutrófilos/metabolismo , Neutrófilos/patologia , Transdução de Sinais , Pele/metabolismo , Pele/patologia , Receptor 4 Toll-Like/genética , Adulto Jovem
13.
Front Immunol ; 11: 1258, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32903598

RESUMO

S100A8 and S100A9 function as essential factors in inflammation and also exert antitumor or tumorigenic activity depending on the type of cancer. Chronic eosinophilic leukemia (CEL) is a rare hematological malignancy having elevated levels of eosinophils and characterized by the presence of the FIP1L1-PDGFRA fusion gene. In this study, we examined the pro-apoptotic mechanisms of S100A8 and S100A9 in FIP1L1-PDGFRα+ eosinophilic cells and hypereosinophilic patient cells. S100A8 and S100A9 induce apoptosis of the FIP1L1-PDGFRα+ EoL-1 cells via TLR4. The surface TLR4 expression increased after exposure to S100A8 and S100A9 although total TLR4 expression decreased. S100A8 and S100A9 suppressed the FIP1L1-PDGFRα-mediated signaling pathway by downregulating FIP1L1-PDGFRα mRNA and protein expression and triggered cell apoptosis by regulating caspase 9/3 pathway and Bcl family proteins. S100A8 and S100A9 also induced apoptosis of imatinib-resistant EoL-1 cells (EoL-1-IR). S100A8 and S100A9 blocked tumor progression of xenografted EoL-1 and EoL-1-IR cells in NOD-SCID mice and evoked apoptosis of eosinophils derived from hypereosinophilic syndrome as well as chronic eosinophilic leukemia. These findings may contribute to a progressive understanding of S100A8 and S100A9 in the pathogenic and therapeutic mechanism of hematological malignancy.


Assuntos
Apoptose , Calgranulina A/metabolismo , Calgranulina B/metabolismo , Síndrome Hipereosinofílica/etiologia , Síndrome Hipereosinofílica/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Células Cultivadas , Doença Crônica , Resistencia a Medicamentos Antineoplásicos , Feminino , Expressão Gênica , Humanos , Síndrome Hipereosinofílica/tratamento farmacológico , Síndrome Hipereosinofílica/patologia , Mesilato de Imatinib/farmacologia , Mesilato de Imatinib/uso terapêutico , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Modelos Biológicos , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/genética , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Proteínas Recombinantes
14.
Front Microbiol ; 10: 2219, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31608039

RESUMO

An increasing number of severe infections caused by Staphylococcus aureus ST398 strains has been observed. However, it has not been elucidated whether all ST398 strains are equally virulent. We collected 13 strains from China and Canada to test in a Caenorhabditis elegans infection model and compared their whole genome sequences (WGS) to explore potential insights into their virulence. All isolates belonged to ST398-methicillin-susceptible S. aureus (MSSA) with variant spa types (t034, t571, t1451, t1250). Pulsed field gel electrophoresis (PFGE) and WGS analyses showed that the 13 isolates clustered into 3 genomic types (Types A-C). WGS and prophage phylogenetic analyses also revealed that the strains could be divided into 3 phage groups (Groups 1-3), which correlated with high-, moderate-, and low-nematocidal activities, with mean killing rates of 94, 67, and 40%, respectively. Group 1 carried ϕSa3-Group 1 (ϕSa3-G1), Group 2 carried ϕSa3-G2, and Group 3 lacked ϕSa3. Interestingly, strain GD1706 (that genetically clustered within Type C) and strain GD487 (within Type B) both carried ϕSa3-G1 like phages and killed 92% of the nematodes, similar to the Type A strains carrying ϕSa3-G1. This study demonstrated that different ST398 sub-lineages possess variable virulence capacities, depending on the presence or absence, as well as the structure of the prophage ϕSa3 that carries virulence factors. IMPORTANCE: Since first being reported in the early 2000s, Staphylococcus aureus ST398 has not only become recognized as a frequent colonizing strain in economically important livestock animals, but has also proven to be a concern for infection in humans and, in particular, has been linked to higher rates of severe invasive human infections. We collected ST398 strains from China and Canada to test in a worm (Caenorhabditis elegans) infection model and compared their whole genome sequences to gain insight into pathogenesis. We have shown that different ST398 sub-strains differ in their virulence potential based on the presence or absence and structure of prophage ϕSa3, which carries important virulence factors. Our observations suggest that ST398 strains are relatively heterogeneous from a clinical perspective, and more studies are needed to differentiate between virulent and non-virulent ST398 strains to determine the true global spread of relevant sub-strains.

15.
Front Microbiol ; 9: 1531, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30042755

RESUMO

The genomic comparison of virulent (TW20), moderately virulent (CMRSA6/CMRSA3), and avirulent (M92) strains from a genetically closely-related MRSA ST239 sub-lineage revealed striking similarities in their genomes and antibiotic resistance profiles, despite differences in virulence and pathogenicity. The main differences were in the spa gene (coding for staphylococcal protein A), lpl genes (coding for lipoprotein-like membrane proteins), cta genes (genes involved in heme synthesis), and the dfrG gene (coding for a trimethoprim-resistant dihydrofolate reductase), as well as variations in the presence or content of some prophages and plasmids, which could explain the virulence differences of these strains. TW20 was positive for all genetic traits tested, compared to CMRSA6, CMRSA3, and M92. The major components differing among these strains included spa and lpl with TW20 carrying both whereas CMRSA6/CMRSA3 carry spa identical to TW20 but have a disrupted lpl. M92 is devoid of both these traits. Considering the role played by these components in innate immunity and virulence, it is predicted that since TW20 has both the components intact and functional, these traits contribute to its pathogenesis. However, CMRSA6/CMRSA3 are missing one of these components, hence their intermediately virulent nature. On the contrary, M92 is completely devoid of both the spa and lpl genes and is avirulent. Mobile genetic elements play a potential role in virulence. TW20 carries three prophages (ϕSa6, ϕSa3, and ϕSPß-like), a pathogenicity island and two plasmids. CMRSA6, CMRSA3, and M92 contain variations in one or more of these components. The virulence associated genes in these components include staphylokinase, entertoxins, antibiotic/antiseptic/heavy metal resistance and bacterial persistence. Additionally, there are many hypothetical proteins (present with variations among strains) with unknown function in these mobile elements which could be making an important contribution in the virulence of these strains. The above mentioned repertoire of virulence components in TW20 likely contributes to its increased virulence, while the absence and/or modification of one or more of these components in CMRSA6/CMRSA3 and M92 likely affects the virulence of the strains.

16.
ACS Omega ; 2(12): 8760-8769, 2017 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-31457406

RESUMO

The aromatic amino acids, Tyr or Trp, which line the active-site walls of esterases, stabilize the catalytic His loop via hydrogen bonding. A Tyr residue is preferred in extremophilic esterases (psychrophilic or hyperthermophilic esterases), whereas a Trp residue is preferred in moderate-temperature esterases. Here, we provide evidence that Tyr and Trp play distinct roles in cold adaptation of the psychrophilic esterase EstSP1 isolated from an Arctic bacterium Sphingomonas glacialis PAMC 26605. Stern-Volmer plots showed that the mutation of Tyr191 to Ala, Phe, Trp, and His resulted in reduced conformational flexibility of the overall protein structure. Interestingly, the Y191W and Y191H mutants showed increased thermal stability at moderate temperatures. All Tyr191 mutants showed reduced catalytic activity relative to wild-type EstSP1. Our results indicate that Tyr with its phenyl hydroxyl group is favored for increased conformational flexibility and high catalytic activity of EstSP1 at low temperatures at the expense of thermal stability. The results of this study suggest that, in the permanently cold Arctic zone, enzyme activity has been selected for psychrophilic enzymes over thermal stability. The results presented herein provide novel insight into the roles of Tyr and Trp residues for temperature adaptation of enzymes that function at low, moderate, and high temperatures.

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