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1.
Crit Rev Food Sci Nutr ; 63(24): 6946-6959, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35156482

RESUMO

It is well-known that some bacteria can promote human and animal health. Bacteria of the genus Carnobacterium, while underexplored, have demonstrated significant probiotic and bioprotective potential. In this review, the recent scientific advances in this area are discussed. There are several requirements for a strain to be considered a probiotic or bioprotective agent, including the absence of antimicrobial resistance and the ability to colonize the gastrointestinal tract. Several researchers have reported such features in Carnobacterium bacteria, especially with regard to the production of antimicrobial substances. Research into animal production has advanced, especially in the aquaculture field, wherein inhibitory activity has been demonstrated against several important pathogens (for example Vibrio), and improvement in zootechnical indexes is evident. With respect to human health-related applications, research is still in the early stages. However, excellent in vitro results against pathogens, such as Candida albicans and Pseudomonas aeruginosa, have been reported. Carnobacterium bacteria have been assessed for a variety of applications in food, including direct application to the matrix and application to smart packaging, with proven effectiveness against Listeria monocytogenes. However, there is a lack of in vivo studies on Carnobacterium applications, which hinders its applications in various industries despite its high potential.


Assuntos
Carnobacterium , Listeria monocytogenes , Animais , Humanos , Qualidade dos Alimentos , Inocuidade dos Alimentos , Microbiologia de Alimentos
2.
Crit Rev Food Sci Nutr ; 62(19): 5267-5283, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33554635

RESUMO

Population growth directly affects the global food supply, demanding a higher production efficiency without farmland expansion - in view of limited land resources and biodiversity loss worldwide. In such scenario, intensive agriculture practices have been widely used. A commonly applied method to maximize yield in animal production is the use of subtherapeutic doses of antibiotics as growth promoters. Because of the strong antibiotic selection pressure generated, the intense use of antibiotic growth promoters (AGP) has been associated to the rise of antimicrobial resistance (AMR). Also, cross-resistance can occur, leading to the emergence of multidrug-resistant pathogens and limiting treatment options in both human and animal health. Thereon, alternatives have been studied to replace AGP in animal production. Among such alternatives, essential oils and essential oil components (EOC) stand out positively from others due to, besides antimicrobial effectiveness, improving zootechnical indexes and modulating genes involved in resistance mechanisms. This review summarizes recent studies in essential oils and EOC for zoonotic bacteria control, providing detailed information about the molecular-level effects of their use in regard to AMR, and identifying important gaps to be filled within the animal production area.


Assuntos
Anti-Infecciosos , Óleos Voláteis , Animais , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Farmacorresistência Bacteriana , Óleos Voláteis/farmacologia
3.
Microbiology (Reading) ; 167(11)2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34738887

RESUMO

The genus Salmonella is closely associated with foodborne outbreaks and animal diseases, and reports of antimicrobial resistance in Salmonella species are frequent. Several alternatives have been developed to control this pathogen, such as cell-free supernatants (CFS). Our objective here was to evaluate the use of lactic acid bacteria (LAB) CFS against Salmonella in vitro. Seventeen strains of LAB were used to produce CFS, and their antimicrobial activity was screened towards six strains of Salmonella. In addition, CFS were also pH-neutralized and/or boiled. Those with the best results were lyophilized. MICs of lyophilized CFS were 11.25-22.5 g l-1. Freeze-dried CFS were also used to supplement swine and poultry feed (11.25 g kg-1) and in vitro simulated digestion of both species was performed, with Salmonella contamination of 5×106 and 2×105 c.f.u. g-1 of swine and poultry feed, respectively. In the antimicrobial screening, all acidic CFS were able to inhibit the growth of Salmonella. After pH neutralization, Lactobacillus acidophilus Llorente, Limosilactobacillus fermentum CCT 1629, Lactiplantibacillus plantarum PUCPR44, Limosilactobacillus reuteri BioGaia, Lacticaseibacillus rhamnosus ATCC 7469 and Pediococcus pentosaceus UM116 CFS were the only strains that partially maintained their antimicrobial activity and, therefore, were chosen for lyophilization. In the simulated swine digestion, Salmonella counts were reduced ≥1.78 log c.f.u. g-1 in the digesta containing either of the CFS. In the chicken simulation, a significant reduction was obtained with all CFS used (average reduction of 0.59±0.01 log c.f.u. ml-1). In general, the lyophilized CFS of L. fermentum CCT 1629, L. rhamnosus ATCC 7469 and L. acidophilus Llorente presented better antimicrobial activity. In conclusion, CFS show potential as feed additives to control Salmonella in animal production and may be an alternative to the use of antibiotics, minimizing problems related to antimicrobial resistance.


Assuntos
Lactobacillales , Probióticos , Salmonelose Animal , Animais , Lactobacillus , Probióticos/farmacologia , Salmonella , Salmonelose Animal/microbiologia , Suínos
4.
Intervirology ; 63(1-6): 33-45, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32966990

RESUMO

BACKGROUND: Arboviruses co-circulating within a population that are transmitted by the same vector have the potential to cause coinfections. Coinfections with dengue virus (DENV), Zika virus (ZIKV), and chikungunya virus (CHIKV) have been occurring in Brazil, but it is not well-understood how human responses vary during mono- or coinfections and whether they play different roles in pathogenesis. METHODS: We investigated the clinical, virological, and immunological status during patients' acute infections, focusing on the CCL/CXC chemokines, proinflammatory, as well as anti-inflammatory cytokines levels quantified by ELISAs. Viral load was determined by qRT-PCR in serum samples from 116 acute DENV, ZIKV, CHIKV, DENV/ZIKV, and CHIKV/ZIKV-infected adult patients from Brazil. RESULTS: Most of the acute patients displayed fever, headache, prostration, and myalgia, regardless of the type of arbovirus infection. Zika viral load was higher in CHIKV/ZIKV coinfected patients compared with ZIKV or DENV/ZIKV infections. All infected individuals presented increased concentrations of C-X-C motif chemokine ligand 10/interferon protein-10 (CXCL10/IP-10), C-C motif chemokine ligand 2/monocyte chemoattractant protein-1 (CCL2/MCP-1), and tumor necrosis factor alpha (TNF-α) compared to healthy donors. Interestingly, the ZIKV group separated from CHIKV/ZIKV due to higher levels of interleukin-10 (IL-10) and lower levels of TNF-α. While DENV/ZIKV differentiated from CHIKV due to their higher levels of CCL2/MCP-1, in CHIKV- and CHIKV/ZIKV-infected patients, levels of CXC10/IP-10, CCL2/MCP-1, and migration inhibitory factor (MIF) were associated with CHIKV viral load. By contrast, in DENV/ZIKV- and CHIKV/ZIKV-infected patients, levels of CXCL10/IP-10, CCL2/MCP-1, and TNF-α showed a significant inverse correlation with ZIKV viral load. CONCLUSIONS: From all the circulating mediators measured, we detected differences of IL-10, TNF-α, and CCL2/MCP-1 between arbovirus groups. We hypothesize that CXC10/IP-10, CCL2/MCP-1, and MIF in the CHIKV-infected group could regulate the CHIKV viral load, while CXC10/IP-10, CCL2/MCP-1, and TNF-α in DENV/ZIKV, and CHIKV/ZIKV groups, could regulate ZIKV viral load.


Assuntos
Febre de Chikungunya , Citocinas/sangue , Dengue , Infecção por Zika virus , Adulto , Brasil , Quimiocinas CC/sangue , Quimiocinas CXC/sangue , Febre de Chikungunya/imunologia , Febre de Chikungunya/virologia , Vírus Chikungunya/fisiologia , Coinfecção , Dengue/imunologia , Vírus da Dengue/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Carga Viral , Adulto Jovem , Zika virus/fisiologia , Infecção por Zika virus/imunologia , Infecção por Zika virus/virologia
5.
World J Microbiol Biotechnol ; 35(10): 158, 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31595344

RESUMO

Presence of bacterial contaminants at levels > 107 colony forming units per milliliter (CFU/mL) during ethanol production processes reduces the alcoholic fermentation yield by 30%. Antibiotics are currently used to control contamination, but their residues may be detected in yeast extract, restricting this by-product trade to several countries. Thus, the objective of this study was to assess antimicrobial activity of the natural compounds hops extract, 4-hydroxybenzoic acid, nisin Z, and lysozyme against Lactobacillus fermentum, Leuconostoc mesenteroides, and Saccharomyces cerevisiae, aiming development of a formula. Minimum Inhibitory Concentration of each antimicrobial was determined for bacteria and subsequently, nisin (30 mg/L) and hops extract (5 mg/L) were tested together, showing inhibitory effects combining doses of each antimicrobial that were equivalent to an eightfold reduction of their original Minimum Inhibitory Concentrations (3.75 and 0.625 mg/L, respectively), resulting in a FICIndex of 0.25. Thereon, a formula containing both compounds was developed and tested in fermentation assays, promoting reductions on bacterial population and no severe interferences in yeast viability or population even at extreme doses. Therefore, these compounds have great potential to successfully substitute conventional antibiotics in the ethanol industry.


Assuntos
Anti-Infecciosos/farmacologia , Etanol/metabolismo , Fermentação/fisiologia , Humulus/química , Extratos Vegetais/farmacologia , Antibacterianos/farmacologia , Microbiologia Industrial , Lactobacillales/efeitos dos fármacos , Limosilactobacillus fermentum/efeitos dos fármacos , Leuconostoc mesenteroides/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Muramidase/farmacologia , Nisina/análogos & derivados , Nisina/farmacologia , Parabenos/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharum/química
6.
J Sci Food Agric ; 98(14): 5235-5241, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29652439

RESUMO

BACKGROUND: Brazil produces approximately 63 million tons of corn kernels annually, which is commonly contaminated with fungi and mycotoxins. The objective of this study was to evaluate the efficacy of gaseous allyl isothiocyanate (AITC) to inhibit the growth of Aspergillus parasiticus and Fusarium verticillioides, and mycotoxin production (aflatoxins B1 , B2 , G1 and G2 , fumonisins B1 and B2 ) in corn during 180 days of storage. RESULTS: AITC at 50 µL L-1 resulted in a significant reduction of the fungal population (P < 0.05) after 180 days, decreasing 3.17 log(CFU g-1 ) and 3.9 log(CFU g-1 ) of A. parasiticus and F. verticillioides respectively in comparison with the control. In addition, 10 and 50 µL L-1 treatments prevented the production of fumonisin B1 for the whole period. Aflatoxins were not detected in either control or treated groups. Residual levels of AITC in corn treated with 10 µL L-1 and 50 µL L-1 were detected up to 14 days and 30 days respectively. CONCLUSION: Prophylactic treatment with AITC reduced the fungal population and inhibited fumonisin B1 production in stored corn, exhibiting great potential to be applied in corn silos to prevent fungi contamination and minimize mycotoxin levels. © 2018 Society of Chemical Industry.


Assuntos
Aspergillus/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Fusarium/efeitos dos fármacos , Isotiocianatos/farmacologia , Micotoxinas/metabolismo , Zea mays/microbiologia , Aspergillus/crescimento & desenvolvimento , Aspergillus/metabolismo , Contaminação de Alimentos/análise , Armazenamento de Alimentos , Fungicidas Industriais/química , Fusarium/crescimento & desenvolvimento , Fusarium/metabolismo , Isotiocianatos/química
7.
Pathogens ; 12(3)2023 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-36986399

RESUMO

Bioactive peptides (BAPs) derived from food proteins have been extensively studied for their health benefits, majorly exploring their potential use as nutraceuticals and functional food components. These peptides possess a range of beneficial properties, including antihypertensive, antioxidant, immunomodulatory, and antibacterial activities, and are naturally present within dietary protein sequences. To release food-grade antimicrobial peptides (AMPs), enzymatic protein hydrolysis or microbial fermentation, such as with lactic acid bacteria (LAB), can be employed. The activity of AMPs is influenced by various structural characteristics, including the amino acid composition, three-dimensional conformation, liquid charge, putative domains, and resulting hydrophobicity. This review discusses the synthesis of BAPs and AMPs, their potential for controlling foodborne pathogens, their mechanisms of action, and the challenges and prospects faced by the food industry. BAPs can regulate gut microbiota by promoting the growth of beneficial bacteria or by directly inhibiting pathogenic microorganisms. LAB-promoted hydrolysis of dietary proteins occurs naturally in both the matrix and the gastrointestinal tract. However, several obstacles must be overcome before BAPs can replace antimicrobials in food production. These include the high manufacturing costs of current technologies, limited in vivo and matrix data, and the difficulties associated with standardization and commercial-scale production.

8.
Anim Health Res Rev ; : 1-13, 2023 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-38073081

RESUMO

Animal husbandry is increasingly under pressure to meet world food demand. Thus, strategies are sought to ensure this productivity increment. The objective of this review was to gather advances in the use of bacterial probiotics in animal production. Lactobacilli correspond to the most used bacterial group, with several beneficial effects already reported and described, as well as the Enterococcus and Pediococcus genera - being the latter expressively used in aquaculture. Research on the Bifidobacterium genus is mostly focused on human health, which demonstrates great effects on blood biochemical parameters. Such results sustain the possibility of expanding its use in veterinary medicine. Other groups commonly assessed for human medicine but with prospective expansion to animal health are the genera Leuconostoc and Streptococcus, which have been demonstrating interesting effects on the prevention of viral diseases, and in dentistry, respectively. Although bacteria from the genera Bacillus and Lactococcus also have great potential for use in animal production, a complete characterization of the candidate strain must be previously made, due to the existence of pathogenic and/or spoilage variants. It is noteworthy that a growing number of studies have investigated the genus Propionibacterium, but still in very early stages. However, the hitherto excellent results endorse its application. In this way, in addition to the fact that bacterial probiotics represent a promising approach to promote productivity increase in animal production, the application of other strains than the traditionally employed genera may allow the exploitation of novel mechanisms and enlighten unexplored possibilities.

9.
Vet Res Commun ; 47(3): 1357-1368, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36823482

RESUMO

Lactic acid bacteria (LAB) are an important option for Salmonella control in animal production, resulting in lower antibiotic use. The objective of this research was to isolate LAB from meat products and from commercial probiotics sold as nutritional supplements for in vitro verification of their bioprotective potential. Eleven bacteria were identified as Pediococcus acidilactici, two as Lacticaseibacillus rhamnosus, one as Lacticaseibacillus paracasei paracasei, one as Limosilactobacillus fermentum, and one as a consortium of Lactobacillus delbrueckii bulgaricus and L. fermentum. All bacteria showed inhibitory activity against Salmonella, with emphasis on the inhibition of P. acidilactici PUCPR 011 against Salmonella Enteritidis 33SUSUP, S. Enteritidis 9SUSP, S. Enteritidis 56301, S. Enteritidis CRIFS 1016, Salmonella Typhimurium ATCC™ 14,028®, and Salmonella Gallinarum AL 1138, with inhibition halos of 7.3 ± 0.5 mm, 7.7 ± 1.0 mm, 9.0 ± 1.8 mm, 7.3 ± 0.5 mm, 7.7 ± 1.0 mm, and 7.3 ± 0.5, respectively. The isolates P. acidilactici PUCPR 011, P. acidilactici PUCPR 012, P. acidilactici PUCPR 014, L. fermentum PUCPR 005, L. paracasei paracasei PUCPR 013, and L. rhamnosus PUCPR 010 showed inhibition greater than 2 mm against at least 3 Salmonella and were used for encapsulation and in vitro digestion. The encapsulation efficiency ranged from 76.89 ± 1.54 to 116.48 ± 2.23%, and the population after 12 months of storage was from 5.31 ± 0.17 to 9.46 ± 0.09 log CFU/g. When simulating swine and chicken digestion, there was a large reduction in bacterial viability, stabilizing at concentrations close to 2.5 log CFU/mL after the analyses. The analyzed bacteria showed strong in vitro bioprotective potential; further analyses are required to determine in vivo effectiveness.


Assuntos
Lactobacillales , Animais , Suínos , Lactobacillales/fisiologia , Antibacterianos/farmacologia , Galinhas , Salmonella typhimurium
10.
Nutrients ; 14(24)2022 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-36558415

RESUMO

The estimated and concerning rise in world population over the next few years and the consequent increase in food demand will lead to a deterioration in global food security. To avoid or reduce this world crisis, informed and empowered consumers are turning to sustainable and nutrient-rich foods that substitute animal products, also reducing their associated environmental impact. Moreover, due to the demonstrated influence of diet on the risk of high incidence and mortality of noncommunicable diseases, the current established food pattern is focused on the consumption of foods that have functionality for health. Among these new foods, traditional and underutilized plants are gaining interest as alternative protein sources providing nutritional and biological properties. In this work, the potential of Erythrina edulis (chachafruto) proteins as a source of multifunctional peptides after transit through the gastrointestinal tract has been demonstrated, with antioxidant and immunostimulating effects in both biochemical assays and cell culture. While low molecular weight peptides released during the digestive process were found to be responsible for protection against oxidative stress mediated by their radical scavenging activity, high molecular weight peptides exerted immunostimulating effects by upregulation of immunoresponse-associated biomarkers. The findings of this study support the promising role of chachafruto proteins as a new antioxidant and immunostimulatory ingredient for functional foods and nutraceuticals.


Assuntos
Erythrina , Animais , Erythrina/química , Erythrina/metabolismo , Antioxidantes/metabolismo , Peptídeos/química , Proteínas , Digestão
11.
Pathogens ; 11(5)2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35631030

RESUMO

Introduction: It is a consensus that inflammatory mediators produced by immune cells contribute to changes in endothelial permeability in dengue. We propose to relate inflammatory mediators seen in dengue patients with the in vitro alteration of endothelial cells (ECs) cultured with serum from these patients. Methods: Patients with mild (DF) to moderate and severe dengue (DFWS/Sev) were selected. ELISA quantified inflammatory mediators. Expression of adhesion molecules and CD147 were evaluated in the ECs cultured with the patient's serum by flow cytometry. We assessed endothelial permeability by measuring transendothelial electrical resistance in cocultures of ECs with patient serum. Results: Dengue infection led to an increase in inflammatory mediators-the IL-10 distinguished DF from DFWS/Sev. There were no changes in CD31, CD54, and CD106 but decreased CD147 expression in ECs. DFWS/Sev sera induced a greater difference in endothelial permeability than DF sera. Correlation statistical test indicated that low IL-10 and IFN-γ and high CCL5 maintain the integrity of ECs in DF patients. In contrast, increased TNF, IFN-γ, CXCL8, and CCL2 maintain EC integrity in DFWS/Sev patients. Conclusions: Our preliminary data suggest that a subset of inflammatory mediators may be related to the maintenance or loss of endothelial integrity, reflecting the clinical prognosis.

12.
Viruses ; 14(2)2022 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-35215843

RESUMO

High levels of T helper 17 cell (Th17)-related cytokines have been shown in acute Zika virus (ZIKV) infection. We hypothesized that the high levels of Th17-related cytokines, associated with a regulatory environment during pregnancy, create a favorable milieu for the differentiation of CD4+Th17 cells. We present data from a cross-sectional study on mothers who confirmed ZIKV infection by qRT-PCR and their children. We also recruited non-pregnant women infected with ZIKV in the same period. ZIKV infection occurred between 2015 and 2017. We collected samples for this study between 2018 and 2019, years after the initial infection. We highlight that, after in vitro stimulation with ZIKV CD4 megapool (ZIKV MP), we found a lower frequency of IL-17-producing CD4+ T cells (Th17), especially in the mothers, confirmed by the decrease in IL-17 production in the supernatant. However, a higher frequency of CD4+ IL-17+ IFN-γ+ T cells (Th1Th17) responding to the ZIKV MP was observed in the cells of the mothers and children but not in those of the non-pregnant women. Our data indicate that the priming of CD4 T cells of the Th1Th17 phenotype occurred preferentially in the mothers who gave birth to children with CZS and in the children.


Assuntos
Mães , Complicações Infecciosas na Gravidez/imunologia , Subpopulações de Linfócitos T/imunologia , Células Th17/imunologia , Infecção por Zika virus/imunologia , Adulto , Linfócitos T CD4-Positivos/imunologia , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Interferon gama/imunologia , Interleucina-17/imunologia , Células T de Memória/imunologia , Pessoa de Meia-Idade , Gravidez , Receptores CCR6/imunologia , Células Th1/imunologia , Adulto Jovem , Zika virus/imunologia
13.
PLoS One ; 17(11): e0277612, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36395285

RESUMO

Mayaro virus (MAYV, Togaviridae) and Oropouche orthobunyavirus (OROV, Peribunyaviridae) are emerging enzootic arboviruses in Latin America. Outbreaks of febrile illness associated with MAYV and OROV have been reported among humans mainly in the northern region of Brazil since the 1980s, and recent data suggest these viruses have circulated also in more populated areas of western Brazil. MAYV shares mosquito vectors with yellow fever virus and it has been historically detected during yellow fever epidemics. Aiming to investigate the transmission of OROV and MAYV at the human-animal interface during a yellow fever, chikungunya and Zika outbreaks in Brazil, we conducted a retrospective molecular investigation in 810 wild and domestic animals, 106 febrile patients, and 22.931 vectors collected from 2016 to 2018 in Cuiaba and Campo Grande metropolitan regions, western Brazil. All samples tested negative for OROV and MAYV RNA by RT-qPCR. Findings presented here suggest no active circulation of MAYV and OROV in the sampled hosts. Active surveillance and retrospective investigations are instrumental approaches for the detection of cryptic and subclinical activity of enzootic arboviruses and together serve as a warning system to implement appropriate actions to prevent outbreaks.


Assuntos
Arbovírus , Orthobunyavirus , Febre Amarela , Infecção por Zika virus , Zika virus , Animais , Humanos , Brasil/epidemiologia , Estudos Retrospectivos , Orthobunyavirus/genética , Arbovírus/genética
14.
Cells ; 10(5)2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-34064728

RESUMO

Th17 cells are recognized as indispensable in inducing protective immunity against bacteria and fungi, as they promote the integrity of mucosal epithelial barriers. It is believed that Th17 cells also play a central role in the induction of autoimmune diseases. Recent advances have evaluated Th17 effector functions during viral infections, including their critical role in the production and induction of pro-inflammatory cytokines and in the recruitment and activation of other immune cells. Thus, Th17 is involved in the induction both of pathogenicity and immunoprotective mechanisms seen in the host's immune response against viruses. However, certain Th17 cells can also modulate immune responses, since they can secrete immunosuppressive factors, such as IL-10; these cells are called non-pathogenic Th17 cells. Here, we present a brief review of Th17 cells and highlight their involvement in some virus infections. We cover these notions by highlighting the role of Th17 cells in regulating the protective and pathogenic immune response in the context of viral infections. In addition, we will be describing myocarditis and multiple sclerosis as examples of immune diseases triggered by viral infections, in which we will discuss further the roles of Th17 cells in the induction of tissue damage.


Assuntos
Miocardite/imunologia , Células Th17/metabolismo , Viroses/imunologia , Adenoviridae , Animais , Doenças Autoimunes/imunologia , Vírus Chikungunya , Citocinas/imunologia , Vírus da Dengue , Humanos , Sistema Imunitário , Imunossupressores/farmacologia , Inflamação , Interleucina-10/biossíntese , Linfócitos/citologia , Esclerose Múltipla/imunologia , Esclerose Múltipla/metabolismo , Esclerose Múltipla/virologia , Miocardite/metabolismo , Miocardite/virologia , Orthomyxoviridae , SARS-CoV-2 , Simplexvirus , Células Th1/citologia , Células Th2/citologia , Viroses/tratamento farmacológico , Viroses/metabolismo , Zika virus
15.
Nat Commun ; 12(1): 367, 2021 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-33446650

RESUMO

Xylanolytic enzymes from glycoside hydrolase family 43 (GH43) are involved in the breakdown of hemicellulose, the second most abundant carbohydrate in plants. Here, we kinetically and mechanistically describe the non-reducing-end xylose-releasing exo-oligoxylanase activity and report the crystal structure of a native GH43 Michaelis complex with its substrate prior to hydrolysis. Two distinct calcium-stabilized conformations of the active site xylosyl unit are found, suggesting two alternative catalytic routes. These results are confirmed by QM/MM simulations that unveil the complete hydrolysis mechanism and identify two possible reaction pathways, involving different transition state conformations for the cleavage of xylooligosaccharides. Such catalytic conformational promiscuity in glycosidases is related to the open architecture of the active site and thus might be extended to other exo-acting enzymes. These findings expand the current general model of catalytic mechanism of glycosidases, a main reaction in nature, and impact on our understanding about their interaction with substrates and inhibitors.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/metabolismo , Xanthomonas/enzimologia , Proteínas de Bactérias/genética , Sítios de Ligação , Catálise , Domínio Catalítico , Cristalografia por Raios X , Glicosídeo Hidrolases/genética , Cinética , Modelos Moleculares , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Xanthomonas/química , Xanthomonas/genética , Xilose/química , Xilose/metabolismo
16.
Nat Commun ; 12(1): 4049, 2021 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-34193873

RESUMO

Xyloglucans are highly substituted and recalcitrant polysaccharides found in the primary cell walls of vascular plants, acting as a barrier against pathogens. Here, we reveal that the diverse and economically relevant Xanthomonas bacteria are endowed with a xyloglucan depolymerization machinery that is linked to pathogenesis. Using the citrus canker pathogen as a model organism, we show that this system encompasses distinctive glycoside hydrolases, a modular xyloglucan acetylesterase and specific membrane transporters, demonstrating that plant-associated bacteria employ distinct molecular strategies from commensal gut bacteria to cope with xyloglucans. Notably, the sugars released by this system elicit the expression of several key virulence factors, including the type III secretion system, a membrane-embedded apparatus to deliver effector proteins into the host cells. Together, these findings shed light on the molecular mechanisms underpinning the intricate enzymatic machinery of Xanthomonas to depolymerize xyloglucans and uncover a role for this system in signaling pathways driving pathogenesis.


Assuntos
Parede Celular/metabolismo , Citrus/microbiologia , Glucanos/metabolismo , Glicosídeo Hidrolases/metabolismo , Fatores de Virulência/genética , Xanthomonas/metabolismo , Xilanos/metabolismo , Proteínas de Bactérias/metabolismo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Ativação Transcricional , Sistemas de Secreção Tipo III/metabolismo , Fatores de Virulência/metabolismo , Xanthomonas/genética , Xanthomonas/patogenicidade
17.
Front Immunol ; 12: 610456, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33679748

RESUMO

Background: Zika virus (ZIKV) infection causes for mild and self-limiting disease in healthy adults. In newborns, it can occasionally lead to a spectrum of malformations, the congenital Zika syndrome (CZS). Thus, little is known if mothers and babies with a history of ZIKV infection were able to develop long-lasting T-cell immunity. To these issues, we measure the prevalence of ZIKV T-cell immunity in a cohort of mothers infected to the ZIKV during pregnancy in the 2016-2017 Zika outbreak, who gave birth to infants affected by neurological complications or asymptomatic ones. Results: Twenty-one mothers and 18 children were tested for IFN-γ ELISpot and T-cell responses for flow cytometry assays in response to CD4 ZIKV and CD8 ZIKV megapools (CD4 ZIKV MP and CD8 ZIKV MP). IFN-γ ELISpot responses to ZIKV MPs showed an increased CD4 and CD8 T-cell responses in mothers compared to children. The degranulation activity and IFN-γ-producing CD4 T cells were detected in most mothers, and children, while in CD8 T-cells, low responses were detected in these study groups. The total Temra T cell subset is enriched for IFN-γ+ CD4 T cells after stimulation of CD4 ZIKV MP. Conclusion: Donors with a history of ZIKV infection demonstrated long-term CD4 T cell immunity to ZIKV CD4 MP. However, the same was not observed in CD8 T cells with the ZIKV CD8 MP. One possibility is that the cytotoxic and pro-inflammatory activities of CD8 T cells are markedly demonstrated in the early stages of infection, but less detected in the disease resolution phase, when the virus has already been eliminated. The responses of mothers' T cells to ZIKV MPs do not appear to be related to their children's clinical outcome. There was also no marked difference in the T cell responses to ZIKV MP between children affected or not with CZS. These data still need to be investigated, including the evaluation of the response of CD8 T cells to other ZIKV peptides.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Memória Imunológica , Infecção por Zika virus/imunologia , Zika virus/imunologia , Adulto , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linfócitos T CD8-Positivos/metabolismo , Reações Cruzadas/imunologia , Estudos Transversais , Feminino , Humanos , Imunidade Materno-Adquirida , Imunofenotipagem , Testes de Neutralização , Gravidez , Complicações Infecciosas na Gravidez , Adulto Jovem , Infecção por Zika virus/sangue , Infecção por Zika virus/epidemiologia
18.
Artigo em Inglês | MEDLINE | ID: mdl-32500063

RESUMO

The glycoside hydrolase family 39 (GH39) is a functionally expanding family with limited understanding about the molecular basis for substrate specificity and extremophilicity. In this work, we demonstrate the key role of the positive-subsite region in modulating substrate affinity and how the lack of a C-terminal extension impacts on oligomerization and structural stability of some GH39 members. The crystallographic and SAXS structures of a new GH39 member from the phytopathogen Xanthomonas citri support the importance of an extended C-terminal to promote oligomerization as a molecular strategy to enhance thermal stability. Comparative structural analysis along with site-directed mutagenesis showed that two residues located at the positive-subsite region, Lys166 and Asp167, are critical to substrate affinity and catalytic performance, by inducing local changes in the active site for substrate binding. These findings expand the molecular understanding of the mechanisms involved in substrate recognition and structural stability of the GH39 family, which might be instrumental for biological insights, rational enzyme engineering and utilization in biorefineries.

19.
Mater Sci Eng C Mater Biol Appl ; 114: 111031, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32993990

RESUMO

Surface-modified hydrogel films were designed to control the bacterial colonization on their surface and to promote cell proliferation through the gradual insertion of highly hydrophobic functional monomers. These hydrogel films were deposited via spin-coating technique, using muscovite mica as a substrate. These samples were then exposed to different external stimuli to produce wrinkled patterns. The relationship between the monomers which compose the hydrogel, was varied to alter the hydrophobic/hydrophilic balance of the final composite. Contact angle and confocal Raman spectroscopy measurements were carried out to characterize the surface and the bulk of the hydrogel film. Cell proliferation and antimicrobial tests were performed using premyoblastic murine cells (C2C12-GFP) and RAW 264.7 (ATCC® TIB-71) macrophagic cell lines, and also for bacteria strains, Staphylococcus aureus and Escherichia coli. The results indicate that the inclusion of the TFPMA produces an increase in cell proliferation, together with a decrease in living bacterial colonies after 48 h, both for Gram-positive or Gram-negative species.


Assuntos
Hidrogéis , Metilgalactosídeos , Animais , Antibacterianos/farmacologia , Hidrogéis/farmacologia , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Staphylococcus aureus
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