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1.
Nat Commun ; 11(1): 5431, 2020 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-33110079

RESUMO

Physical forces have profound effects on cellular behavior, physiology, and disease. Perhaps the most intruiguing and fascinating example is the formation of catch-bonds that strengthen cellular adhesion under shear stresses. Today mannose-binding by the Escherichia coli FimH adhesin remains one of the rare microbial catch-bond thoroughly characterized at the molecular level. Here we provide a quantitative demonstration of a catch-bond in living Gram-positive pathogens using force-clamp spectroscopy. We show that the dock, lock, and latch interaction between staphylococcal surface protein SpsD and fibrinogen is strong, and exhibits an unusual catch-slip transition. The bond lifetime first grows with force, but ultimately decreases to behave as a slip bond beyond a critical force (~1 nN) that is orders of magnitude higher than for previously investigated complexes. This catch-bond, never reported for a staphylococcal adhesin, provides the pathogen with a mechanism to tightly control its adhesive function during colonization and infection.


Assuntos
Adesinas Bacterianas/química , Infecções Estafilocócicas/microbiologia , Staphylococcus/metabolismo , Adesinas Bacterianas/genética , Adesinas Bacterianas/metabolismo , Aderência Bacteriana , Fibrinogênio/química , Fibrinogênio/metabolismo , Humanos , Ligação Proteica , Análise Espectral , Infecções Estafilocócicas/metabolismo , Staphylococcus/química , Staphylococcus/genética , Staphylococcus/crescimento & desenvolvimento
2.
PLoS One ; 15(8): e0236713, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32750089

RESUMO

Coagulase-negative staphylococci (CoNS) are the most common isolates from blood culture in neonates resulting in high mortality and morbidity. This study investigated CoNS obtained from blood cultures of neonates for antibiotic resistance and virulence factors, and possible association with inflammatory response (C-reactive protein). A total of 93 CoNS isolates were collected from 76 blood cultures of neonates at the Maternity hospital in Kuwait in a six-month period and investigated for susceptibility to antibiotics, carriage of staphylococcal cassette chromosome mec (SCCmec), and virulence-associated genes. The 93 CoNS isolates consisted of S. epidermidis (76; 81.7%), S. capitis (12; 12.9%), S. hominis (2; 2.1%), S. warneri (2; 2.1%) and S. haemolyticus (1; 1.0%). Eighty-six (92.4%) of the isolates were resistant to cefoxitin (MR-CoNS) while 49 (52.7%) expressed multi-antibiotic resistance. The methicillin-resistant isolates (MR-CoNS) carried SCCmec III, SCCmec IVa and four combinations of SCCmec types including SCCmec types I+IVa (one S. warneri and 25 S. epidermidis isolates), types I+III (one S. epidermidis isolate), types III+IVa (six S. epidermidis isolates) and types I+III+IVa (one S. epidermidis isolate). The most common virulence-related genes were icaC, seb, arc detected in 69.7%, 60.5%, 40.8% of the isolates respectively. Two isolates were positive for tst1. No association between C-reactive protein and antibiotic resistance or virulence factors was established. This study revealed that S. epidermidis carrying different SCCmec genetic elements, was the dominant CoNS species isolated from neonatal blood cultures with 90.3% and 36.6% of the isolates positive for genes for biofilm and ACME production respectively.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Recém-Nascido Prematuro , Infecções Estafilocócicas/microbiologia , Staphylococcus/efeitos dos fármacos , Toxinas Bacterianas/genética , Biofilmes , Coagulase/metabolismo , Feminino , Genes Bacterianos , Humanos , Recém-Nascido , Kuweit , Masculino , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Staphylococcus/enzimologia , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismo , Fatores de Virulência/genética , Fatores de Virulência/metabolismo
3.
Appl Environ Microbiol ; 86(17)2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32591386

RESUMO

Staphylococcus aureus and other coagulase-positive Staphylococcus spp. bind the Fc region of IgG antibodies through expression of protein A (SpA). These species have consequently been a source of false-positive signals in antibody-based assays designed to detect other target bacteria. Here, flow cytometry was used to study the influence of a number of factors on the SpA-mediated binding of single cells to an anti-human IgG antibody, including strain, heat killing, overnight storage, growth phase, cell physiology, surface adhesion, and growth in model food systems. Through the costaining of antibody-stained cells with the permeability dye propidium iodide and calcein violet AM, the cell physiological status was related to SpA-mediated antibody binding. Generally, permeabilized cells lacking esterase activity did not strongly bind antibody. The binding of a number of commercially available polyclonal IgG antibodies to non-Staphylococcus spp. was also characterized. Not all SpA-expressing species showed strong binding of mouse IgG, and one species not known to express SpA showed strong binding. Most SpA-expressing strains bound rabbit IgG antibodies to some extent, whereas only one strain bound goat IgG. To reduce or eliminate SpA-mediated IgG binding, the following products were evaluated as blocking reagents and applied prior to staining with primary or secondary antibody: normal rabbit serum, mouse IgG isotype control, goat IgG, and a commercial FcR blocking reagent. Only the FcR blocking reagent consistently reduced SpA-mediated binding of Staphylococcus spp. to antibodies against other species and could be recommended as a blocking reagent in immunoassays designed to detect non-Staphylococcus species.IMPORTANCE This study characterizes a widespread but little-studied problem associated with the antibody-based detection of microbes-the Staphylococcus protein A (SpA)-mediated binding of IgG antibodies-and offers a solution: the use of commercial FcR blocking reagent. A common source of false-positive signals in the detection of microbes in clinical, food, or environmental samples can be eliminated by applying this study's findings. Using flow cytometry, the authors demonstrate the extent of heterogeneity in a culture's SpA-mediated binding of antibodies and that the degree of SpA-mediated antibody binding is strain, growth phase, and food matrix dependent and influenced by simulated food processing treatments and cell adherence. In addition, our studies of SpA-mediated binding of Staphylococcus spp. to antibodies against other bacterial species produced a very nuanced picture, leading us to recommend testing against multiple strains of S. aureus and S. hyicus of all antibodies to be incorporated into any immunoassay designed to detect a non-Staphylococcus spp.


Assuntos
Anticorpos Antibacterianos/imunologia , Receptores Fc/metabolismo , Proteína Estafilocócica A/imunologia , Staphylococcus/metabolismo , Anticorpos Antibacterianos/metabolismo , Citometria de Fluxo , Ligação Proteica , Proteína Estafilocócica A/metabolismo
4.
Chemosphere ; 258: 127386, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32559495

RESUMO

Contamination of agricultural land with heavy metal is a serious biological and environmental issue. Such threat can be challenged by exploring the plant symbiotic microbes that can improve plant growth through phyto-hormones secretion and chromate chelation. In the current study, chromate resistant rhizospheric Staphylococcus arlettae strain MT4 was isolated from the rhizosphere of Malvestrum tricuspadatum L. The strain showed potential to secrete phytohormones and plant growth promoting secondary metabolites under induced chromate stress, making it a best suitable candidate in chromate stress alleviation. Moreover, the rhizobacterium MT4 significantly promoted the net assimilation and relative growth rate of sunflower grown in the presence of chromate (100 ppm). Chromate stress alleviation strategy of MT4 strain was three-fold. MT4 alleviated chromate stress and promoted the sunflower growth by suppressing the chromate intake by the host, modulating phytohormones and strengthening of the host's antioxidant system. The improved antioxidant system was confirmed by noticing lower ROS accumulation and improved ROS scavenging, lower peroxidase activity and higher accumulation of phenols and flavonoids.


Assuntos
Antioxidantes/metabolismo , Cromatos/toxicidade , Helianthus/efeitos dos fármacos , Reguladores de Crescimento de Planta/metabolismo , Rizosfera , Poluentes do Solo/toxicidade , Staphylococcus/crescimento & desenvolvimento , Biodegradação Ambiental , Cromatos/metabolismo , Helianthus/metabolismo , Helianthus/microbiologia , Oxirredução , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Poluentes do Solo/metabolismo , Staphylococcus/metabolismo
5.
Balkan Med J ; 37(4): 215-221, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32270947

RESUMO

Background: Coagulase-negative staphylococci, which belong to the normal microbiota of the skin and mucous membranes, are opportunistic pathogens. sasX, a newly described protein, is thought to play an important role in nasal colonization and methicillin-resistant Staphylococcus aureus virulence, and it may be acquired from coagulase-negative staphylococci by horizontal gene transfer. It has been considered that understanding the function of sasX gene may help clarify the relevance of the different adhesion mechanisms in the pathogenesis of infections associated with biofilm. Aims: To investigate the sasX gene presence, staphylococcal cassette chromosome mec types, and antimicrobial resistance patterns of invasive and noninvasive coagulase-negative staphylococci isolates. Study Design: Cross-sectional study. Methods: The study included a total of 180 coagulase-negative staphylococci strains. Non-invasive isolates (n=91) were obtained from the hands of healthy volunteers who do not work at the hospital (n=30), the nasal vestibule of healthy volunteer hospital workers (n=26), and central venous catheter (n=35). Invasive isolates (n=89) were isolated from peripheral blood cultures of inpatients who do not have catheters. All isolates were identified by conventional microbiological methods, automated systems, and, if needed, with matrix-assisted laser desorption/ionization-time of flight. Staphylococcal cassette chromosome mec typing, sasX and mec gene detection, antibiotic susceptibility, and sasX gene sequence analysis were performed. Results: Peripheral blood, central venous catheter colonization, and nasal vestibule isolates were positive for the sasX gene, whereas hand isolates were negative. sasX gene was present in 17 isolates, and no statistical significance was found between invasive and noninvasive isolates (p=0.173). Sequence analysis of the sasX genes showed high homology to related proteins of Staphylococcus phage SPbeta-like and Staphylococcus epidermidis RP62A. staphylococcal cassette chromosome mec type V was the most prevalent regardless of species. staphylococcal cassette chromosome mec type II was more frequent in invasive isolates and found to be statistically important for invasive and noninvasive S. epidermidis isolates (p=0.029). Staphylococcus haemolyticus isolates had the overall highest resistance rates. Resistance to ciprofloxacin, trimethoprim-sulfamethoxazole, and erythromycin was found to be higher in isolates from catheter and blood culture. Staphylococcus hominis isolates had the highest rate for inducible clindamycin resistance. None of the isolates were resistant to vancomycin, teicoplanin, and linezolid. Conclusion: The sasX gene is detected in 9.44% of the isolates. There is no statistical difference between the sasX-positive and -negative isolates in terms of antibacterial resistance and the presence of sasX and SCCmec types. Further studies about the role of sasX at virulence in coagulase-negative staphylococci, especially from clinical samples such as tracheal aspirate and abscess isolates, and distribution of staphylococcal cassette chromosome mec types are needed.


Assuntos
Coagulase/análise , Staphylococcus/genética , Staphylococcus/metabolismo , Coagulase/sangue , Coagulase/metabolismo , Estudos Transversais , Humanos , Testes de Sensibilidade Microbiana/métodos , Staphylococcus/isolamento & purificação , Staphylococcus capitis/genética , Staphylococcus capitis/isolamento & purificação , Staphylococcus epidermidis/genética , Staphylococcus epidermidis/isolamento & purificação , Staphylococcus haemolyticus/genética , Staphylococcus haemolyticus/isolamento & purificação , Staphylococcus hominis/genética , Staphylococcus hominis/isolamento & purificação , Staphylococcus lugdunensis/genética , Staphylococcus lugdunensis/isolamento & purificação , Staphylococcus saprophyticus/genética , Staphylococcus saprophyticus/isolamento & purificação
6.
Nat Commun ; 11(1): 1539, 2020 03 24.
Artigo em Inglês | MEDLINE | ID: mdl-32210242

RESUMO

Idiopathic pulmonary fibrosis (IPF) is a chronic and fatal disease of unknown etiology; however, apoptosis of lung alveolar epithelial cells plays a role in disease progression. This intractable disease is associated with increased abundance of Staphylococcus and Streptococcus in the lungs, yet their roles in disease pathogenesis remain elusive. Here, we report that Staphylococcus nepalensis releases corisin, a peptide conserved in diverse staphylococci, to induce apoptosis of lung epithelial cells. The disease in mice exhibits acute exacerbation after intrapulmonary instillation of corisin or after lung infection with corisin-harboring S. nepalensis compared to untreated mice or mice infected with bacteria lacking corisin. Correspondingly, the lung corisin levels are significantly increased in human IPF patients with acute exacerbation compared to patients without disease exacerbation. Our results suggest that bacteria shedding corisin are involved in acute exacerbation of IPF, yielding insights to the molecular basis for the elevation of staphylococci in pulmonary fibrosis.


Assuntos
Proteínas Reguladoras de Apoptose/imunologia , Proteínas de Bactérias/imunologia , Fibrose Pulmonar Idiopática/imunologia , Peptídeos/imunologia , Staphylococcus/imunologia , Idoso , Animais , Apoptose/imunologia , Proteínas Reguladoras de Apoptose/análise , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Bactérias/análise , Proteínas de Bactérias/metabolismo , Líquido da Lavagem Broncoalveolar/química , Líquido da Lavagem Broncoalveolar/imunologia , Modelos Animais de Doenças , Células Epiteliais/imunologia , Células Epiteliais/patologia , Feminino , Voluntários Saudáveis , Humanos , Fibrose Pulmonar Idiopática/genética , Fibrose Pulmonar Idiopática/microbiologia , Fibrose Pulmonar Idiopática/patologia , Pulmão/imunologia , Pulmão/microbiologia , Pulmão/patologia , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Transgênicos , Peptídeos/análise , Peptídeos/metabolismo , Staphylococcus/metabolismo , Staphylococcus/patogenicidade , Exacerbação dos Sintomas , Linfócitos T Reguladores/imunologia , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/imunologia
7.
J Dairy Sci ; 103(4): 3076-3081, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32037175

RESUMO

Our objective was to assess the enterotoxigenic potential of coagulase-negative staphylococci (CNS) isolated from bovine milk in Poland. We analyzed CNS isolates collected from 133 bovine milk batches from dairy farms in the Western Pomerania district during 2 milking seasons. A total of 163 isolates were screened by multiplex/duplex PCR for the presence of 18 of 25 enterotoxin genes identified so far in Staphylococcus aureus. The CNS strains presumed to be potentially enterotoxigenic were identified at the species level based on MALDI-TOF mass spectrometry analysis. Based on the presence of an amplicon matching D, G, or O enterotoxin genes, we initially identified 32 of the 163 CNS isolates tested as potentially enterotoxigenic. However, only 8 of these strains were confirmed as such. All 8 of these CNS strains, identified as Staphylococcus haemolyticus, harbored the seg genes, a prerequisite for enterotoxin G production, but so far not connected with staphylococcal foodborne poisoning cases. None of the CNS bovine milk isolates tested was a potential producer of classical A to E staphylococcal enterotoxins. Results of our surveys revealed a low prevalence of enterotoxigenic CNS among the milk isolates from dairy farms in the Western Pomerania district, Poland, suggesting that they pose only a mild health risk in milk. In our opinion, confirmed formation of nonspecific amplicons leading to false-positive results excludes multiplex/duplex PCR as the sole method for assessing the enterotoxigenic potential of CNS.


Assuntos
Enterotoxinas/metabolismo , Leite/microbiologia , Infecções Estafilocócicas/veterinária , Staphylococcus/genética , Animais , Bovinos , Enterotoxinas/genética , Enterotoxinas/isolamento & purificação , Feminino , Polônia/epidemiologia , Reação em Cadeia da Polimerase/veterinária , Infecções Estafilocócicas/microbiologia , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismo , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação
8.
Infect Immun ; 88(5)2020 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-32094259

RESUMO

The intracellular lifestyle of bacteria is widely acknowledged to be an important mechanism in chronic and recurring infection. Among the Staphylococcus genus, only Staphylococcus aureus and Staphylococcus pseudintermedius have been clearly identified as intracellular in nonprofessional phagocytic cells (NPPCs), for which the mechanism is mainly fibronectin-binding dependent. Here, we used bioinformatics tools to search for possible new fibronectin-binding proteins (FnBP-like) in other Staphylococcus species. We found a protein in Staphylococcus delphini called Staphylococcus delphini surface protein Y (SdsY). This protein shares 68% identity with the Staphylococcus pseudintermedius surface protein D (SpsD), 36% identity with S. aureus FnBPA, and 39% identity with S. aureus FnBPB. The SdsY protein possesses the typical structure of FnBP-like proteins, including an N-terminal signal sequence, an A domain, a characteristic repeated pattern, and an LPXTG cell wall anchor motif. The level of adhesion to immobilized fibronectin was significantly higher in all S. delphini strains tested than in the fibronectin-binding-deficient S. aureus DU5883 strain. By using a model of human osteoblast infection, the level of internalization of all strains tested was significantly higher than with the invasive-incompetent S. aureus DU5883. These findings were confirmed by phenotype restoration after transformation of DU5883 by a plasmid expression vector encoding the SdsY repeats. Additionally, using fibronectin-depleted serum and murine osteoblast cell lines deficient for the ß1 integrin, the involvement of fibronectin and ß1 integrin was demonstrated in S. delphini internalization. The present study demonstrates that additional staphylococcal species are able to invade NPPCs and proposes a method to identify FnBP-like proteins.


Assuntos
Fagócitos/metabolismo , Fagócitos/microbiologia , Staphylococcus/metabolismo , Staphylococcus/patogenicidade , Adesinas Bacterianas/metabolismo , Animais , Aderência Bacteriana/fisiologia , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Linhagem Celular , Parede Celular/metabolismo , Fibronectinas/metabolismo , Humanos , Integrina beta1/metabolismo , Camundongos
9.
J Phys Chem Lett ; 11(5): 1934-1939, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32067463

RESUMO

Slow polypeptide conformational changes on time scales of >1 s are generally assumed to be highly cooperative two-state transitions, reflecting the high energy barrier. However, few experimental characterizations have tested the validity of this assumption. We performed residue-specific NMR thermodynamic analysis of the 27-residue lantibiotic peptide, nukacin ISK-1, to characterize the isomerization between two topological states on the second time scale. Unexpectedly, the thermal transition behaviors were distinct among peptide regions, indicating that the topological isomerization process is a mosaic of different degrees of cooperativity. The conformational change path between the two NMR structures was deduced by a targeted molecular dynamics simulation. The unique side-chain threading motions through the monosulfide rings are the structural basis of the high energy barrier, and the nonlocal interactions in the hydrophobic core are the structural basis of the cooperativity. Taken together, we provide an energetic description of the topological isomerization of nukacin ISK-1.


Assuntos
Bacteriocinas/química , Ressonância Magnética Nuclear Biomolecular , Bacteriocinas/metabolismo , Dicroísmo Circular , Isomerismo , Simulação de Dinâmica Molecular , Staphylococcus/metabolismo , Termodinâmica
10.
Sci Rep ; 10(1): 330, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941915

RESUMO

Carotenoids are associated with several important biological functions as antenna pigments in photosynthesis or protectives against oxidative stress. Occasionally they were also discussed as part of the cold adaptation mechanism of bacteria. For two Staphylococcus xylosus strains we demonstrated an increased content of staphyloxanthin and other carotenoids after growth at 10 °C but no detectable carotenoids after grow at 30 °C. By in vivo measurements of generalized polarization and anisotropy with two different probes Laurdan and TMA-DPH we detected a strong increase in membrane order with a simultaneous increase in membrane fluidity at low temperatures accompanied by a broadening of the phase transition. Increased carotenoid concentration was also correlated with an increased resistance of the cells against freeze-thaw stress. In addition, the fatty acid profile showed a moderate adaptation to low temperature by increasing the portion of anteiso-branched fatty acids. The suppression of carotenoid synthesis abolished the effects observed and thus confirmed the causative function of the carotenoids in the modulation of membrane parameters. A differential transcriptome analysis demonstrated the upregulation of genes involved in carotenoid syntheses under low temperature growth conditions. The presented data suggests that upregulated synthesis of carotenoids is a constitutive component in the cold adaptation strategy of Staphylococcus xylosus and combined with modifications of the fatty acid profile constitute the adaptation to grow under low temperature conditions.


Assuntos
Carotenoides/metabolismo , Fluidez de Membrana/fisiologia , Staphylococcus/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Carotenoides/análise , Cromatografia Líquida de Alta Pressão , Temperatura Baixa , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Staphylococcus/genética , Staphylococcus/crescimento & desenvolvimento , Estresse Fisiológico , Regulação para Cima , Xantofilas/análise , Xantofilas/metabolismo
11.
Meat Sci ; 159: 107917, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494521

RESUMO

In this study, effects of ingoing nitrite level (0, 50, 100 and 150 mg/kg), use of sodium ascorbate, addition of starter culture (Lactobacillus plantarum GM77 + Staphylococcus xylosus GM92) and cooking level (control, medium, medium well, well done and very well done) on nitrosamine formation in heat-treated sucuk, a type of semi-dry fermented sausage, were investigated. The use of ascorbate had no significant effect on NDMA (N-Nitrosodimethylamine) and NPIP (N-Nitrosopiperidine) contents in the presence of starter culture. A higher NPYR (N- Nitrosopyrrolidine) content was detected in the group with starter culture at 150 mg/kg nitrite level in comparison to the group without starter culture. Cooking level affected all identified nitrosamines very significantly. Ingoing nitrite level × cooking level interaction was only effective on NPIP and advanced cooking levels (well done and very well done) at higher ingoing nitrite levels (100 and 150 mg/kg) resulted in significant increases in NPIP content.


Assuntos
Ácido Ascórbico/química , Culinária , Dimetilnitrosamina/química , Produtos da Carne/análise , Nitritos/química , Animais , Bacteriocinas , Bovinos , Microbiologia de Alimentos , Temperatura Alta , Fosfatos de Inositol , Lactobacillus plantarum/metabolismo , Produtos da Carne/microbiologia , Carne Vermelha , Staphylococcus/metabolismo
12.
Meat Sci ; 160: 107958, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31669862

RESUMO

This study focused on sarcoplasmic and myofibrillar protein degradation and the formation of peptides with antioxidant activity by mixed starters (Lactobacillus plantarum CD101 and Staphylococcus simulans NJ201). Gel electrophoresis indicated that the mixed starters can hydrolyze both sarcoplasmic and myofibrillar proteins, and the concentration of peptides increased (P < .05). Compared with the control group, using mixed starters led to a significant increase (P < .05) in the DPPH radical scavenging activity, Fe2+ chelating activity, and ABTS radical scavenging activity of sarcoplasmic proteins, but demonstrated no significant difference in myofibrillar proteins. Two hydrophobic fractions (C2, C5) separated by RP-HPLC in the inoculation groups with sarcoplasmic proteins showed high DPPH radical scavenging activity (66.60%, 60.50%). Eighteen peptides were identified by LC-MS/MS, which mainly arose from triosephosphate isomerase, creatine kinase M-type, and glyceraldehyde-3-phosphate dehydrogenase. Hydrophobic amino acids accounted for a large proportion. Our results indicate that mixed starters affect proteolytic characterization and contribute to the formation of peptides with antioxidant capacity in sarcoplasmic proteins.


Assuntos
Lactobacillus plantarum/metabolismo , Produtos da Carne/microbiologia , Proteólise , Staphylococcus/metabolismo , Animais , Antioxidantes/química , Fermentação , Proteínas Musculares/metabolismo , Miofibrilas/metabolismo , Peptídeos/metabolismo , Suínos
13.
Int J Food Microbiol ; 315: 108419, 2020 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-31734616

RESUMO

The effects of glucose and sucrose on the gene expression of nitric oxide synthase (NOS) in Staphylococcus vitulinus and colour formation in dry sausages were investigated. The results showed that sucrose addition promoted nitric oxide (NO) production in media when compared with glucose. In addition, sucrose could up-regulate nos (encoding NOS) and katA (encoding catalase KatA) gene expression by enhancing oxidative stress levels. In the sausages inoculated with S. vitulinus, a*-values (indicating redness) of the sausages with added sucrose were higher than those of samples with added glucose (P < 0.05) but did not differ from those in the nitrite treatment group (P > 0.05). The UV-vis spectra results showed that nitrosylmyoglobin (NO-Mb) was formed in the sausages with either S. vitulinus or nitrite added. In the S. vitulinus-inoculated sausages, sucrose addition led to a higher NO-Mb content than that after glucose addition, which was attributed to up-regulation of the nos gene. This study provides a potential method to enhance NO yield in S. vitulinus and colour formation in dry sausages without nitrite addition.


Assuntos
Catalase/biossíntese , Glucose/metabolismo , Óxido Nítrico Sintase/biossíntese , Staphylococcus/metabolismo , Sacarose/metabolismo , Animais , Catalase/genética , Cor , Produtos da Carne/análise , Mioglobina/biossíntese , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/genética , Nitritos/metabolismo , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Staphylococcus/enzimologia , Staphylococcus/genética , Ativação Transcricional , Regulação para Cima
14.
Mol Microbiol ; 113(2): 369-380, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31732993

RESUMO

The NreB-NreC two-component system of Staphylococcus carnosus for O2 sensing cooperates with the accessory nitrate sensor NreA in the NreA-NreB-NreC system for coordinated sensing and regulation of nitrate respiration by O2 and nitrate. ApoNreA (NreA in the absence of nitrate) interacts with NreB and inhibits NreB autophosphorylation (and activation). NreB contains the phosphatase motif DxxxQ. The present study shows that NreB on its own was inactive for the dephosphorylation of the phosphorylated response regulator NreC (NreC-P), but co-incubation with NreB and NreA stimulated NreC-P dephosphorylation. Either the presence of NreA · NO 3 - instead of apoNreA or mutation of the phosphatase motif (D160 or Q164) of NreB abrogated phosphatase activity of NreB. Phosphatase activity was observed for anoxic (active) NreB as well as oxic NreB, therefore the functional state of NreB is not relevant for phosphatase activity. Thus, NreB is a bifunctional sensor kinase with an integral cryptic phosphatase activity. Activation of phosphatase activity and dephosphorylation of NreC-P requires NreA as a cofactor. Accordingly, NreA and nitrate have major and dual roles in NreA-NreB-NreC regulation by (i) inhibiting NreB phosphorylation and (ii) triggering a kinase/phosphatase switch of NreB when present as apoNreA.


Assuntos
Fosfotransferases/metabolismo , Staphylococcus/metabolismo , Proteínas de Bactérias/metabolismo , Nitratos/metabolismo , Oxigênio/metabolismo , Monoéster Fosfórico Hidrolases , Fosforilação
15.
Int Microbiol ; 23(2): 253-261, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31485794

RESUMO

The potential of indigenous bacterial strains to accumulate three metals (Cr, Ni, Pb) was exploited here to remediate the polluted environment. In the present study, metal resistance profiles identified three most potential isolates which could tolerate 700-1000 µg/ml of Ni, 500-1000 µg/ml of Cr, and 1000-1600 µg/ml of Pb. These three bacterial strains were identified as Stenotrophomonas sp. MB339, Klebsiella pneumoniae MB361, and Staphylococcus sp. MB371. UV-Visible and atomic absorption spectrophotometric (AAS) analysis revealed gradual increase in percentage accumulation with increase in time due to increased biomass. Quantitative assessments exhibited maximum removal of Cr (83.51%) by Klebsiella pneumoniae MB361, Pb (85.30%), and Ni (48.78%) by Stenotrophomonas MB339, at neutral pH and 37 °C, whereas Staphylococcus sp. MB371 sorbed 88.33% of Pb at slightly acidic pH. The present study therefore supports the effective utilization of indigenous bacteria for comprehensive treatment of metal-rich industrial effluents.


Assuntos
Bactérias/metabolismo , Bioacumulação , Resíduos Industriais , Metais Pesados/metabolismo , Bactérias/classificação , Bactérias/isolamento & purificação , Biodegradação Ambiental , Cromo/metabolismo , Klebsiella pneumoniae/isolamento & purificação , Klebsiella pneumoniae/metabolismo , Chumbo/metabolismo , Níquel/metabolismo , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismo , Stenotrophomonas/isolamento & purificação , Stenotrophomonas/metabolismo
16.
Meat Sci ; 161: 108022, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31838366

RESUMO

Three coagulase-negative staphylococci (CNS) species were investigated for gene expression of nitric oxide synthase (NOS) and the ability of nitrosomyoglobin (NO-Mb) formation in a dry sausage model without nitrite addition. The expression of nos gene was systematically proven from DNA to RNA to protein, and nitric oxide (NO) generation was also directly detected. In the dry sausage model system, the redness (a*-values) of samples inoculated with the three CNS species were higher than those inoculated with Pediococcus pentosaceus and the control (P < 0.05). The results from UV-vis and electron spin resonance spectroscopies revealed that pentacoordinate NO-Mb was formed in the sausages with either CNS or nitrite added. The sausage inoculated with Staphylococcus vitulinus had the highest NO-Mb content among the CNS-treated sausages. Dimer interface residues and phosphorylation sites of NOS in . itulinus differ from the other two CNS species as revealed by amino acid sequences, which may be responsible for the different catalytic activities.


Assuntos
Microbiologia de Alimentos/métodos , Produtos da Carne/microbiologia , Mioglobina/biossíntese , Óxido Nítrico Sintase/metabolismo , Carne de Porco/microbiologia , Staphylococcus/metabolismo , Animais , Produtos da Carne/análise , Modelos Teóricos , Carne de Porco/análise , Suínos
17.
Environ Sci Pollut Res Int ; 26(35): 35968-35977, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31709483

RESUMO

Coal dust from open-cast mines is a significant air pollutant; thus, dust particles and toxins contained in the dust are a severe threat to human health and ecosystems. Microbially induced carbonate precipitation (MICP) is a low-cost and environmentally friendly way to suppress coal dust. With high urease activity and tolerance to coal dust, a bacterial strain, Staphylococcus succinus J3, was isolated from soil in a mine area. Thus, in dust suppression experiments, we used coal dust dominated by fine granule particles (100-250 µm) from an open-cast mine. Consequently, four factors were identified: initial bacterial biomass, calcium concentration, urea concentration, and spraying frequency; we investigated their effects on MICP as a dust suppression technique using one-factor-at-a-time experiments. Maximum threshold broken wind speed (45.5 m s-1) and pressure (912 kPa) were obtained under the following condition: OD600 = 0.7, 40 mmol calcium, 6% (w/w) urea in the bonding solution which was sprayed five times in 35 days. Pearson correlation analysis described that urea concentration and spraying frequency both significantly positive correlations with the threshold broken wind speed and pressure via Pearson analysis. When the coal dust suppression process was complete, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy showed that a solidified layer of calcareous precipitate had formed on the surface of the dust. These results indicate that Staphylococcus succinus J3 has considerable potential for use in MICP as a coal dust suppression technique.


Assuntos
Biodegradação Ambiental , Carbonatos/metabolismo , Carvão Mineral , Poeira , Staphylococcus/metabolismo , Poluição do Ar , Biomassa , Minas de Carvão , Ecossistema , Microscopia Eletrônica de Varredura , Minerais , Mineração , Espectrometria por Raios X , Ureia , Urease
18.
Sci Rep ; 9(1): 17834, 2019 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-31780689

RESUMO

We previously showed that doxycycline (DOX) and carprofen (CPF), a veterinary non-steroidal anti-inflammatory drug, have synergistic antimicrobial activity against methicillin-resistant Staphylococcus pseudintermedius (MRSP) carrying the tetracycline resistance determinant TetK. To elucidate the molecular mechanism of this synergy, we investigated the effects of the two drugs, individually and in combination, using a comprehensive approach including RNA sequencing, two-dimensional differential in-gel electrophoresis, macromolecule biosynthesis assays and fluorescence spectroscopy. Exposure of TetK-positive MRSP to CPF alone resulted in upregulation of pathways that generate ATP and NADH, and promote the proton gradient. We showed that CPF is a proton carrier that dissipates the electrochemical potential of the membrane. In the presence of both CPF and DOX, the energy compensation strategy was attenuated by downregulation of all the processes involved, such as citric acid cycle, oxidative phosphorylation and ATP-providing arginine deiminase pathway. Furthermore, protein biosynthesis inhibition increased from 20% under DOX exposure alone to 75% upon simultaneous exposure to CPF. We conclude that synergistic interaction of the drugs restores DOX susceptibility in MRSP by compromising proton-motive-force-dependent TetK-mediated efflux of the antibiotic. MRSP is unable to counterbalance CPF-mediated PMF depletion by cellular metabolic adaptations, resulting in intracellular accumulation of DOX and inhibition of protein biosynthesis.


Assuntos
Antibacterianos/farmacologia , Carbazóis/farmacologia , Doxiciclina/farmacologia , Farmacorresistência Bacteriana Múltipla , Prótons , Staphylococcus/metabolismo , Trifosfato de Adenosina/metabolismo , Proteínas de Bactérias/metabolismo , Sinergismo Farmacológico , Transporte de Íons , Proteínas de Membrana Transportadoras/metabolismo , Resistência a Meticilina , NADP/metabolismo , Staphylococcus/efeitos dos fármacos , Staphylococcus/genética , Resistência a Tetraciclina
20.
Reprod Biol Endocrinol ; 17(1): 85, 2019 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-31656198

RESUMO

BACKGROUND: Voluntary control of fertility is of paramount importance to the modern society. But since the contraceptive methods available for women have their limitations such as urinary tract infections, allergies, cervical erosion and discomfort, a desperate need exists to develop safe methods. Vaginal contraceptives may be the answer to this problem, as these are the oldest ways of fertility regulation, practiced over the centuries. With minimal systemic involvement, these are also the safest. Natural substances blocking or impairing the sperm motility offer as valuable non-cytotoxic vaginal contraceptives. Antimicrobial peptides (AMPs) isolated from plants, animals and microorganisms are known to possess sperm immobilizing and spermicidal properties. Following this, in the quest for alternative means, we have cloned, over expressed and purified the recombinant sperm agglutinating factor (SAF) from Staphylococcus warneri, isolated from the cervix of a woman with unexplained infertility. METHODS: Genomic library of Staphylococcus warneri was generated in Escherichia coli using pSMART vector and screened for sperm agglutinating factor (SAF). The insert in sperm agglutinating transformant was sequenced and was found to express ribonucleotide-diphosphate reductase-α sub unit. The ORF was sub-cloned in pET28a vector, expressed and purified. The effect of rSAF on motility, viability, morphology, Mg++-dependent ATPase activity and acrosome status of human sperms was analyzed in vitro and contraceptive efficacy was evaluated in vivo in female BALB/c mice. RESULTS: The 80 kDa rSAF showed complete sperm agglutination, inhibited its Mg2+-ATPase activity, caused premature sperm acrosomal loss in vitro and mimicked the pattern in vivo showing 100% contraception in BALB/c mice resulting in prevention of pregnancy. The FITC labeled SAF was found to bind the entire surface of spermatozoa. Vaginal application and oral administration of rSAF to mice for 14 successive days did not demonstrate any significant change in vaginal cell morphology, organ weight and tissue histology of reproductive and non-reproductive organs and had no negative impact in the dermal and penile irritation tests. CONCLUSION: The Sperm Agglutinating Factor from Staphylococcus warneri, natural microflora of human cervix, showed extensive potential to be employed as a safe vaginal contraceptive.


Assuntos
Colo do Útero/microbiologia , Anticoncepcionais Femininos/farmacologia , Aglutinação Espermática/efeitos dos fármacos , Motilidade Espermática/efeitos dos fármacos , Staphylococcus/metabolismo , Acrossomo/efeitos dos fármacos , Acrossomo/fisiologia , Animais , Anticoncepcionais Femininos/metabolismo , Feminino , Biblioteca Genômica , Humanos , Infertilidade Feminina , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Gravidez , Staphylococcus/genética
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