RESUMO
Yeast-bacterium interaction has recently been investigated to benefit the production of cell-bound lipases (CBLs). Staphylococcus hominis AUP19 supported the growth of Magnusiomyces spicifer AW2 in a palm oil mill effluent (POME) medium to produce CBLs through a bioremediation approach, including oil and grease (O&G) and chemical oxygen demand (COD) removals. This research used the yeast-bacterium co-culture to optimize CBLs and cell biomass (CBM) productions through bioremediation using the statistical Plackett-Burman design and response surface methodology-central composite design. The CBLs were finally applied in biodiesel synthesis. The CBM of 13.8 g/L with CBLs activity at 3391 U/L was achieved after incubation at room temperature (RT, 30 ± 2 °C) for 140 h in 50% POME medium, pH 7.0, containing 1.23% (w/v) ammonium sulfate. Bacterium promoted yeast growth to achieve bioremediation with 87.9% O&G removal and 84.5% COD removal. Time course study showed that the CBLs activity was highest at 24 h cultivation (4103 U/L) and retained 80% and 60% of activities at 4 °C and RT after 5 weeks of storage. The CBLs application successfully yielded 77.3% biodiesel from oleic acid (esterification) and 86.4% biodiesel from palm oil (transesterification) within 72 h in solvent-free systems. This study highlights that yeast-bacterium co-culture and POME should receive more attention for potential low-cost CBLs production through bioremediation, i.e., O&G and COD removals, while the CBLs as biocatalysts are promising for significant contribution to an effective strategy for economic green biodiesel production.
Assuntos
Lipase , Óleos de Plantas , Solventes , Óleo de Palmeira , Lipase/metabolismo , Óleos de Plantas/metabolismo , Biocombustíveis , Staphylococcus hominis/metabolismo , Saccharomyces cerevisiae/metabolismo , Técnicas de CoculturaRESUMO
BACKGROUND: Tuberculosis currently stands as the second leading cause of deaths worldwide due to single infectious agent after Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The current challenges of drug resistance in tuberculosis highlight an urgent need to develop newer anti-mycobacterial compounds. In the present study, we report the serendipitous discovery of a bacterial laboratory contaminant (LC-1) exhibiting a zone of growth inhibition on an agar plate seeded with Mycobacterium tuberculosis. RESULTS: We utilized microbiological, biochemical and biophysical approaches to characterize LC-1 and anti-mycobacterial compound(s) in its secretome. Based on 16S rRNA sequencing and BIOLOG analysis, LC-1 was identified as Staphylococcus hominis, a human bacterial commensal. Anti-mycobacterial activity was initially found in 30 kDa retentate that was obtained by ultrafiltration of culture filtrate (CF). SDS-PAGE analysis of peak fractions obtained by size exclusion chromatography of 30 kDa retentate confirmed the presence of high molecular weight (≥ 30 kDa) proteins. Peak fraction-1 (F-1) exhibited inhibitory activity against M. bovis BCG, but not against M. smegmatis, E. coli and S. aureus. The active fraction F-1 was inactivated by treatment with Proteinase K and α-chymotrypsin. However, it retained its anti-mycobacterial activity over a wide range of heat and pH treatment. The anti-mycobacterial activity of F-1 was found to be maintained even after a long storage (~12 months) at - 20 °C. Mass spectrometry analysis revealed that the identified peptide masses do not match with any previously known bacteriocins. CONCLUSIONS: The present study highlights the anti-mycobacterial activity of high molecular weight protein(s) present in culture filtrate of LC-1, which may be tested further to target M. tuberculosis. The heat and pH stability of these proteins add to their characteristics as therapeutic proteins and may contribute to their long shelf life. LC-1 being a human commensal can be tested in future for its potential as a probiotic to treat tuberculosis.
Assuntos
Antituberculosos/química , Proteínas de Bactérias/química , Antituberculosos/isolamento & purificação , Antituberculosos/farmacologia , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/farmacologia , Estabilidade de Medicamentos , Endopeptidase K/metabolismo , Temperatura Alta , Humanos , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Mycobacterium bovis/efeitos dos fármacos , Staphylococcus hominis/metabolismoRESUMO
Here we report a jute endophyte Staphylococcus hominis strain MBL_AB63 isolated from jute seeds which showed promising antimicrobial activity against Staphylococcus aureus SG511 when screening for antimicrobial substances. The whole genome sequence of this strain, annotated using BAGEL4 and antiSMASH 5.0 to predict the gene clusters for antimicrobial substances identified a novel antimicrobial peptide cluster that belongs to the class I lantibiotic group. The predicted lantibiotic (homicorcin) was found to be 82% similar to a reported peptide epicidin 280 having a difference of seven amino acids at several positions of the core peptide. Two distinct peaks obtained at close retention times from a RP-HPLC purified fraction have comparable antimicrobial activities and LC-MS revealed the molecular mass of these peaks to be 3046.5 and 3043.2 Da. The presence of an oxidoreductase (homO) similar to that of epicidin 280- associated eciO or epilancin 15X- associated elxO in the homicorcin gene cluster is predicted to be responsible for the reduction of the first dehydrated residue dehydroalanine (Dha) to 2-hydroxypropionate that causes an increase of 3 Da mass of homicorcin 1. Trypsin digestion of the core peptide and its variant followed by ESI-MS analysis suggests the presence of three ring structures, one in the N-terminal and other two interlocking rings at the C-terminal region that remain undigested. Homicorcin exerts bactericidal activity against susceptible cells by disrupting the integrity of the cytoplasmic membrane through pore formation as observed under FE-SEM.
Assuntos
Bacteriocinas/análise , Endófitos/química , Staphylococcus hominis/química , Endófitos/metabolismo , Espectrometria de Massas , Staphylococcus hominis/metabolismoRESUMO
Staphylococcus hominis is part of the normal human microbiome. Two subspecies, S. hominis hominis (Shh) and S. hominis novobiosepticus (Shn), have clinical significance. Forty-nine S. hominis isolates were analyzed by the MicroScan automated system, SDS-PAGE and MALDI-TOF methods, followed by partial sequencing of the 16S rDNA gene. The trehalose fermentation test, disk diffusion and broth microdilution tests were used to identify (novobiocin test) and access the susceptibility to oxacillin and vancomycin of isolates. The SCCmec elements and genomic diversity were evaluated by PCR and PFGE methods, respectively. Profiles of 28 (57%; 8 Shh and 20 Shn) isolates corroborated with the results found in all the applied methods of identification. The remaining 21 (43%) isolates were phenotypically identified as Shh by MicroScan; however, they were identified as Shn by SDS-PAGE and mass spectral, and confirmed by 16S rDNA sequencing. Among 41 isolates identified as Shn by the molecular and mass spectrometry methods, 19 (41%) were novobiocin-sensitive, and the trehalose test indicated 11 positive isolates, which are considered atypical phenotypic results for this subspecies. In addition, 92.7% of the isolates identified as Shn by these methods carried mecA gene, while only 12.5% of the Shh isolates were positive. Together, the results highlighted the SDS-PAGE and MALDI-TOF MS methods as promising tools for discriminating S. hominis subspecies.
Assuntos
Proteínas de Bactérias/metabolismo , Eletroforese em Gel de Poliacrilamida , Proteoma , Proteômica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Staphylococcus hominis/classificação , Staphylococcus hominis/metabolismo , Humanos , Proteômica/métodosRESUMO
In the present study, a lead (Pb)-resistant bacterium, Staphylococcus hominis strain AMB-2 was isolated from Mandoli industrial area, Delhi and selected for heavy metal biosorption considering multiple heavy metal resistance. In the batch experiment, both living and dead biomasses of strain AMB-2 showed biosorption of Pb and cadmium (Cd) in single and binary systems as analyzed through Inductively coupled plasma-optical emission spectrometry. Living biomass exhibited more biosorption of metals than dead biomass in both single and binary systems. However, in the binary system, metals competed for the attachment sites on the bacterial surface, where Pb got more preference over Cd for the same. The underlying mechanism for the biosorption was attachment of the metal ions through functional groups onto the surface of the biomass as revealed by scanning electron microscope-energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction. Conclusively, this study displayed an effective biotreatment of Pb and Cd from aqueous medium using a low-cost biosorbent prepared from S. hominis strain AMB-2 considering biosafety of microorganisms and an eco-friendly approach.
Assuntos
Chumbo/metabolismo , Metais Pesados/metabolismo , Staphylococcus hominis/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Biodegradação Ambiental , Biomassa , Cádmio/metabolismo , Testes de Sensibilidade Microbiana , Filogenia , Microbiologia do Solo , Staphylococcus hominis/classificação , Staphylococcus hominis/isolamento & purificação , Staphylococcus hominis/ultraestruturaRESUMO
Mammals produce volatile odours that convey different types of societal information. In Homo sapiens, this is now recognised as body odour, a key chemical component of which is the sulphurous thioalcohol, 3-methyl-3-sulfanylhexan-1-ol (3M3SH). Volatile 3M3SH is produced in the underarm as a result of specific microbial activity, which act on the odourless dipeptide-containing malodour precursor molecule, S-Cys-Gly-3M3SH, secreted in the axilla (underarm) during colonisation. The mechanism by which these bacteria recognise S-Cys-Gly-3M3SH and produce body odour is still poorly understood. Here we report the structural and biochemical basis of bacterial transport of S-Cys-Gly-3M3SH by Staphylococcus hominis, which is converted to the sulphurous thioalcohol component 3M3SH in the bacterial cytoplasm, before being released into the environment. Knowledge of the molecular basis of precursor transport, essential for body odour formation, provides a novel opportunity to design specific inhibitors of malodour production in humans.
Assuntos
Proteínas de Bactérias/química , Proteínas de Transporte/química , Dipeptídeos/metabolismo , Regulação Bacteriana da Expressão Gênica , Hexanóis/metabolismo , Odorantes/análise , Staphylococcus hominis/metabolismo , Ácidos Sulfanílicos/metabolismo , Axila/microbiologia , Axila/fisiologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Transporte Biológico , Biotransformação , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Cristalografia por Raios X , Citoplasma/metabolismo , Dipeptídeos/química , Hexanóis/química , Humanos , Cinética , Modelos Moleculares , Odorantes/prevenção & controle , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Staphylococcus hominis/genética , Especificidade por Substrato , Ácidos Sulfanílicos/química , Suor/química , Suor/metabolismo , Suor/microbiologiaRESUMO
The worldwide increase in antibiotic-resistant pathogens means that identification of alternative antibacterial drug targets and the subsequent development of new treatment strategies are urgently required. One such new target is the quorum sensing (QS) system. Coral microbial consortia harbor an enormous diversity of microbes, and are thus rich sources for isolating novel bioactive and pharmacologically valuable natural products. However, to date, the versatility of their bioactive compounds has not been broadly explored. In this study, about two hundred bacterial colonies were isolated from a coral species (Pocillopora damicornis) and screened for their ability to inhibit QS using the bioreporter strain Chromobacterium violaceum ATCC 12472. Approximately 15% (30 isolates) exhibited anti-QS activity, against the indicator strain. Among them, a typical Gram-positive bacterium, D11 (Staphylococcus hominis) was identified and its anti-QS activity was investigated. Confocal microscopy observations showed that the bacterial extract inhibited the biofilm formation of clinical isolates of wild-type P. aeruginosa PAO1 in a dose-dependent pattern. Chromatographic separation led to the isolation of a potent QS inhibitor that was identified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR) spectroscopy as DL-homocysteine thiolactone. Gene expression analyses using RT-PCR showed that strain D11 led to a significant down-regulation of QS regulatory genes (lasI, lasR, rhlI, and rhlR), as well as a virulence-related gene (lasB). From the chemical structure, the target compound (DL-homocysteine thiolactone) is an analog of the acyl-homoserine lactones (AHLs), and we presume that DL-homocysteine thiolactone outcompetes AHL in occupying the receptor and thereby inhibiting QS. Whole-genome sequence analysis of S. hominis D11 revealed the presence of predicted genes involved in the biosynthesis of homocysteine thiolactone. This study indicates that coral microbes are a resource bank for developing QS inhibitors and they will facilitate the discovery of new biotechnologically relevant compounds that could be used instead of traditional antibiotics.
Assuntos
Antozoários/microbiologia , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Bactérias/isolamento & purificação , Bactérias/metabolismo , Percepção de Quorum/efeitos dos fármacos , Acil-Butirolactonas/isolamento & purificação , Acil-Butirolactonas/farmacologia , Animais , Bactérias/genética , Aderência Bacteriana/efeitos dos fármacos , Proteínas de Bactérias/genética , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , China , Chromobacterium , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Bactérias Gram-Positivas/isolamento & purificação , Bactérias Gram-Positivas/metabolismo , Ligases/genética , Metaloendopeptidases/genética , Consórcios Microbianos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/genética , Percepção de Quorum/genética , Água do Mar/microbiologia , Staphylococcus hominis/genética , Staphylococcus hominis/isolamento & purificação , Staphylococcus hominis/metabolismo , Simbiose , Transativadores/genética , Fatores de Transcrição/genética , Virulência/genética , Sequenciamento Completo do GenomaRESUMO
The immunostimulatory effect of phospholipopeptide biosurfactant from Staphylococcus hominis (GenBank Accession No: KJ564272) was assessed with Oreochromis mossambicus. The non-specific (serum lysozyme activity, serum antiprotease activity, serum peroxidase activity and serum bactericidal activity), specific (bacterial agglutination assay) immune responses and disease resistance activity against Aeromonas hydrophila were examined. Fish were intraperitonially injected with water soluble secondary metabolite (biosurfactant) of S. hominis at a dose of 2 mg, 20 mg and 200 mg kg(-1) body weight. Commercial surfactant surfactin (sigma) at 20 mg kg(-1) was used as standard and saline as negative control. All the doses of water soluble biosurfactant tested, significantly enhanced the specific, nonspecific immunity and disease resistance from the day of post administration of phospholipopeptide biosurfactant till the tail of the experimental period. These results clearly indicated that the secondary metabolite isolated from S. hominis stimulates the immunity of finfish thereby could enhance aquaculture production.
Assuntos
Lipoproteínas/imunologia , Peptídeos/imunologia , Staphylococcus hominis/metabolismo , Tensoativos , Tilápia/imunologia , Aeromonas hydrophila/fisiologia , Testes de Aglutinação , Animais , Aquicultura , Resistência à Doença , Doenças dos Peixes/imunologia , Infecções por Bactérias Gram-Negativas/imunologia , Infecções por Bactérias Gram-Negativas/veterinária , Imunização , Lipoproteínas/biossíntese , Muramidase/sangue , Peptídeos/metabolismo , Peroxidase/sangue , Inibidores de Proteases/sangue , Tensoativos/metabolismo , Tilápia/sangueRESUMO
Development of tumour that is resistant to chemotherapeutics and synthetic drugs, coupled with their life-threatening side effects and the adverse effects of surgery and hormone therapies, led to increased research on probiotics' anticancer potentials. The current study investigated the potential of live, heat-killed cells (HKC) and the cytoplasmic fractions (CF) of Enterococcus faecalis and Staphylococcus hominis as anti-breast cancer agents. MCF-7 cell line was treated with 25, 50, 100 and 200 µg/mL each of live, HKC and CF of the bacteria; and cytotoxicity was evaluated for 24, 48 and 72 h using MTT assay. The morphological features of the treated cells were examined by fluorescence microscopy. The stage of cell cycle arrest and apoptosis were quantified by flow cytometry. The bacterial effect on non-malignant breast epithelial cell line, MCF-10A, was assessed using MTT assay for 24, 48 and 72 h. All the three forms of the bacteria caused a significant decrease in MCF-7 (up to 33.29%) cell proliferation in concentration- and time-dependent manner. Morphological features of apoptosis like cell death, cell shrinkage and membrane blebbing were observed. Flow cytometry analyses suggested that about 34.60% of treated MCF-7 was undergoing apoptosis. A strong anti-proliferative activity was efficiently induced through sub-G1 accumulation (up to 83.17%) in treated MCF-7 and decreased number in the G0/G1 phase (74.39%). MCF-10A cells treated with both bacteria showed no significant difference with the untreated (>90% viability). These bacteria can be used as good alternative nutraceutical with promising therapeutic indexes for breast cancer because of their non-cytotoxic effects to normal cells.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Citoplasma/metabolismo , Enterococcus faecalis/metabolismo , Leite Humano/microbiologia , Staphylococcus hominis/metabolismo , Neoplasias da Mama/patologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Enterococcus faecalis/isolamento & purificação , Feminino , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Humanos , Células MCF-7 , Probióticos , Staphylococcus hominis/isolamento & purificaçãoRESUMO
The production of malodour by humans is mediated by bacterial transformation of naturally secreted, non-odorous molecules. Specifically in the underarm (axilla), malodour arises due to biotransformation by the microbiota of dipeptide-conjugated thioalcohols, particularly S-[1-(2-hydroxyethyl)-1-methylbutyl]-(L)-cysteinylglycine (Cys-Gly-3M3SH). This molecule, secreted by the axilla, has a well-established role in malodour when metabolized to free thioalcohol by bacteria. We present Cys-Gly-3M3SH biotransformation data from a library of skin-isolated corynebacteria and staphylococci and report a significant variation in thioalcohol generation across individual bacterial species. Staphylococcus hominis, Staphylococcus haemolyticus and Staphylococcus lugdunensis were particularly efficient Cys-Gly-3M3SH transformers. In contrast, Staphylococcus epidermidis and Corynebacterium tuberculostearicum, both highly prevalent axillary commensals, are low producers of 3M3SH. We also identify significant differences between the ability of several isolates to biotransform Cys-Gly-3M3SH compared to S-benzyl-L-Cys-Gly, a dipeptide-linked version of a commonly used malodour precursor substrate. Finally, using traditional biochemical assays we subsequently establish that Cys-Gly-3M3SH is actively transported into S. hominis, rather than passively diffusing across the membrane. This work significantly enhances our knowledge of Cys-Gly-3M3SH biotransformation by physiologically important bacteria in the axillary microbiota.
Assuntos
Álcoois/metabolismo , Axila/microbiologia , Hexanóis/metabolismo , Pele/microbiologia , Staphylococcus/isolamento & purificação , Staphylococcus/metabolismo , Ácidos Sulfanílicos/metabolismo , Biotransformação , Corynebacterium/classificação , Corynebacterium/isolamento & purificação , Corynebacterium/metabolismo , Humanos , Microbiota/fisiologia , Odorantes/análise , Pele/metabolismo , Staphylococcus/classificação , Staphylococcus epidermidis/metabolismo , Staphylococcus hominis/metabolismo , SimbioseRESUMO
Two studies from Jarosz et al. describe how [GAR(+)], a protein-based epigenetic determinant found mainly in wild yeast strains, can be activated by microbial cross-kingdom communication. With the aid of genetically and ecologically diverse bacteria, yeast can override an ancient regulatory mechanism of glucose repression, promoting both microbial diversity and lifespan extension.
Assuntos
Epigênese Genética , Príons/metabolismo , Saccharomyces cerevisiae/metabolismo , Staphylococcus hominis/metabolismoRESUMO
In experimental science, organisms are usually studied in isolation, but in the wild, they compete and cooperate in complex communities. We report a system for cross-kingdom communication by which bacteria heritably transform yeast metabolism. An ancient biological circuit blocks yeast from using other carbon sources in the presence of glucose. [GAR(+)], a protein-based epigenetic element, allows yeast to circumvent this "glucose repression" and use multiple carbon sources in the presence of glucose. Some bacteria secrete a chemical factor that induces [GAR(+)]. [GAR(+)] is advantageous to bacteria because yeast cells make less ethanol and is advantageous to yeast because their growth and long-term viability is improved in complex carbon sources. This cross-kingdom communication is broadly conserved, providing a compelling argument for its adaptive value. By heritably transforming growth and survival strategies in response to the selective pressures of life in a biological community, [GAR(+)] presents a unique example of Lamarckian inheritance.
Assuntos
Epigênese Genética , Príons/metabolismo , Saccharomyces cerevisiae/metabolismo , Staphylococcus hominis/metabolismo , Fermentação , Glucose/metabolismo , Saccharomyces cerevisiae/genética , Staphylococcus hominis/genética , Vinho/microbiologia , Leveduras/genética , Leveduras/metabolismoRESUMO
Hydramacin-1 (HM1) from the metazoan Hydra exerts antimicrobial activity against a wide range of bacterial strains. Notably, HM1 induces the aggregation of bacterial cells, accompanied by precipitation. To date, the proposed mechanism of peptide-lipid interaction, termed the barnacle model, has not been described on the molecular level. Here, we show by biochemical and biophysical techniques that the lipid-peptide interactions of HM1 are initiated by electrostatic and hydrophobic effects, in particular, by tryptophan and neighboring polar amino acid residues that cause an interfacial localization of the peptide between two self-contained lipid bilayers. The high binding constants of HM1 upon lipid interaction are in the range of other potent antimicrobial peptides, e.g., magainin, and can be reasonably explained by two distinct epitopes on the surface of the peptide's global structure, which both contain SWT(K/R) motifs. The residues of this motif favor localization of the peptide in the head group region of phospholipid bilayers up to a penetration depth of 4 Å and a minor participation of the lipids' hydrocarbon regions. Our results expand the knowledge about the molecular modes of action antimicrobial peptides use to tackle their target cells. Furthermore, the aggregation of living bacteria by HM1 was observed for a broad range of Gram-positive and Gram-negative bacteria. Therefore, the detailed view of peptide-lipid interactions described by the barnacle model consolidates it among the established models.
Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Membrana Celular/metabolismo , Bicamadas Lipídicas/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/metabolismo , Bactérias/metabolismo , Burkholderia cepacia/efeitos dos fármacos , Burkholderia cepacia/metabolismo , Membrana Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Bicamadas Lipídicas/química , Lipídeos , Ligação Proteica , Proteus mirabilis/efeitos dos fármacos , Proteus mirabilis/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/metabolismo , Staphylococcus haemolyticus/efeitos dos fármacos , Staphylococcus haemolyticus/metabolismo , Staphylococcus hominis/efeitos dos fármacos , Staphylococcus hominis/metabolismo , Eletricidade Estática , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/metabolismoRESUMO
Hominicin, antimicrobial peptide displaying potent activity against Staphylococcus aureus ATCC 25923, methicillin-resistant S. aureus (MRSA) ATCC 11435 and vancomycin-intermediate S. aureus (VISA) CCARM 3501, was purified by chloroform extraction, ion-exchange column chromatography and reverse-phase HPLC from culture supernatant of Staphylococcushominis MBBL 2-9. Hominicin exhibited heat stability up to 121 degrees C for 15min and activity under both acidic and basic conditions (from pH 2.0 to 10.0). Hominicin was cleaved into two fragments after treatment with proteinase K, resulting in the loss of its antibacterial activity, while it was resistant to trypsin, alpha-chymotrypsin, pepsin and lipase. The molecular mass of hominicin determined by mass spectrometry was 2038.4Da. LC-mass spectrometry and NMR spectroscopy analyses of the two fragments revealed the sequence of hominicin as DmIle-Dhb-Pro-Ala-Dhb-Pro-Phe-Dhb-Pro-Ala-Ile-Thr-Glu-Ile-Dhb-Ala-Ala-Val-Ile-Ala-Dmp, which had no similarity with other antimicrobial peptides previously reported. The present study is the first report of this novel antimicrobial peptide, which has uncommon amino acid residues like the ones in Class I group and shows potent activity against clinically relevant S. aureus, MRSA and VISA.
Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Proteínas de Bactérias/química , Farmacorresistência Bacteriana , Staphylococcus hominis/metabolismo , Sequência de Aminoácidos , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Staphylococcus hominis/genéticaRESUMO
AIMS: To isolate and characterize an antagonist for use as probiotic agent in the biocontrol of Staphylococcus aureus. METHODS AND RESULTS: Bacteria that exhibited antimicrobial activity against Gram-positive bacteria including Staph. aureus were isolated from 12 healthy women, with Staphylococcus hominis MBBL 2-9 showing the strongest activity. The bacteriocin produced by Staph. hominis MBBL 2-9 was purified by 60% ammonium sulfate saturation, ultrafiltration, HLB cartridge and reverse-phase HPLC. The molecular weight was estimated as 2038.2 Da by MALDI-TOF mass spectrometry. The antagonist survived up to 2 h in artificial gastric juice (pH 2.5) and grew in the presence of 1% porcine bile extract. In addition, Staph. hominis MBBL 2-9 adhered effectively to HT-29 epithelial cell line. CONCLUSION: Staphylococcus hominis MBBL 2-9 exhibited desirable probiotic traits such as acid tolerance, bile resistance and adherence to epithelial cell line. The bacterium also produced a bacteriocin with unique molecular weight and high antimicrobial activity similar to traditional antibiotics. SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first report of a bacteriocin-producing Staph. hominis MBBL 2-9 that has potential for use as a probiotic agent against Staph. aureus.
Assuntos
Probióticos , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/isolamento & purificação , Staphylococcus hominis/fisiologia , Vagina/microbiologia , Adulto , Antibacterianos/farmacologia , Antibiose , Aderência Bacteriana , Bacteriocinas/biossíntese , Bacteriocinas/isolamento & purificação , Linhagem Celular Tumoral , Feminino , Humanos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus hominis/metabolismoRESUMO
With increasing consumer demands for safer, healthier and more natural products, bacterially produced exopolysaccharides (EPSs) are becoming a viable option as an additive in designer-type foods. Fresh milk samples from cattle and sheep were collected from informal settlements in South Africa. After a three day incubation period at 25 degrees C, 550 bacterial strains were isolated and evaluated for EPS production from lactose as sole carbon source. Strains producing EPS on lactose were identified to species level with 16S rRNA gene sequencing and encompass 11 Gram-positive and 6 Gram-negative bacteria. EPS production was assigned for the first time to members of the species Staphylococcus hominis and Enterococcus lactis, and also to apparently novel species of the genera Sphingomonas and Acinetobacter. The polymers consisted mainly out of galactose and glucose, while a few isolates also incorporated rhamnose. Isolates produced diverse biopolymers as seen by significant differences in monomer ratios.
Assuntos
Bactérias/metabolismo , Hexoses/análise , Lactose/metabolismo , Leite/microbiologia , Polissacarídeos Bacterianos/biossíntese , Acinetobacter/isolamento & purificação , Acinetobacter/metabolismo , Animais , Bactérias/genética , Bactérias/isolamento & purificação , Sequência de Bases , Bovinos , Enterococcus/genética , Enterococcus/isolamento & purificação , Enterococcus/metabolismo , Fermentação , Hidrólise , Polissacarídeos Bacterianos/genética , RNA Ribossômico/análise , Homologia de Sequência , Ovinos , África do Sul , Sphingomonas/genética , Sphingomonas/isolamento & purificação , Sphingomonas/metabolismo , Staphylococcus hominis/genética , Staphylococcus hominis/isolamento & purificação , Staphylococcus hominis/metabolismoRESUMO
Staphylococcus hominis KQU-131, isolated from Thai fermented marine fish, produces a heat stable bacteriocin. Structural and genetic analysis indicated that the bacteriocin is a variant of nukacin ISK-1, a type-A(II) lantibiotic, and we termed the bacteriocin nukacin KQU-131. There were three different amino acid residues between nukacin ISK-1 and nukacin KQU-131, one residue in the leader peptide and the other two in the mature peptide.