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1.
World J Microbiol Biotechnol ; 38(9): 162, 2022 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-35834028

RESUMO

Brevinin2-CE (B2CE), a natural peptide containing 37 amino acids, was first isolated from the skin secretions of the Chinese forest frog Rana chensinensis. B2CE shows good antibacterial activity. In this study, a series of B2CE analogs with differences in cationicity, α-helicity, hydrophobicity and amphipathic properties were designed through chain-length deletion and amino acid substitution. The most potent, nontoxic analog, B2CE-N26V5K, was identified by examination of its antibacterial activity, hemolytic activity, and stability under physiological conditions. The increased cationicity, hydrophobicity and more obvious hydrophilic and hydrophobic surface of B2CE-N26-N16WA18KG23K did not improve the antibacterial activity but increased the hemolytic activity of this modified peptide. The helicity might promote antibacterial activity for brevinin-2 peptides, as the 15-aa analogs with lower helicity show decreased potency against different test bacteria (approximately 2- to 72-fold) compared to B2CE-N26V5K. Additionally, the results indicated that the "Rana box" does not affect the antimicrobial activity of brevinin-2 peptides, as B2CE, B2CE-nonDS and B2CE-C31-37 S have similar strong inhibitory effects on both gram-positive and gram-negative bacteria. However, the "Rana box" does affect the hemolytic activity, as the HC50 values of the 3 peptides range from 25 ~ 130 µM. Furthermore, B2CE-N26V5K caused obvious morphological alterations of the bacterial surfaces, as shown by atomic force microscopy. Additionally, B2CE-N26V5K exhibited strong membrane-disrupting activity when examined using the LIVE/DEAD Bac Light Bacterial Viability Kit. Thus, the antibacterial effect of B2CE-N26V5K on gram-negative and gram-positive bacteria may be caused by cell membrane attack. In conclusion, the excellent candidate B2CE-N26V5K was obtained and has application prospects as a novel anti-infective agent.


Assuntos
Anti-Infecciosos , Peptídeos Catiônicos Antimicrobianos , Animais , Antibacterianos/química , Anti-Infecciosos/metabolismo , Peptídeos Catiônicos Antimicrobianos/química , Bactérias/metabolismo , Bactérias Gram-Negativas , Bactérias Gram-Positivas/metabolismo , Hemólise , Testes de Sensibilidade Microbiana , Ranidae/metabolismo
2.
World J Microbiol Biotechnol ; 38(9): 158, 2022 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-35821348

RESUMO

In this mini-review, after a brief introduction into the widespread antimicrobial use of silver ions and nanoparticles against bacteria, fungi and viruses, the toxicity of silver compounds and the molecular mechanisms of microbial silver resistance are discussed, including recent studies on bacteria and fungi. The similarities and differences between silver ions and silver nanoparticles as antimicrobial agents are also mentioned. Regarding bacterial ionic silver resistance, the roles of the sil operon, silver cation efflux proteins, and copper-silver efflux systems are explained. The importance of bacterially produced exopolysaccharides as a physiological (biofilm) defense mechanism against silver nanoparticles is also emphasized. Regarding fungal silver resistance, the roles of metallothioneins, copper-transporting P-type ATPases and cell wall are discussed. Recent evolutionary engineering (adaptive laboratory evolution) studies are also discussed which revealed that silver resistance can evolve rapidly in bacteria and fungi. The cross-resistance observed between silver resistance and resistance to other heavy metals and antibiotics in bacteria and fungi is also explained as a clinically and environmentally important issue. The use of silver against bacterial and fungal biofilm formation is also discussed. Finally, the antiviral effects of silver and the use of silver nanoparticles against SARS-CoV-2 and other viruses are mentioned. To conclude, silver compounds are becoming increasingly important as antimicrobial agents, and their widespread use necessitates detailed understanding of microbial silver response and resistance mechanisms, as well as the ecological effects of silver compounds. Figure created with BioRender.com.


Assuntos
Anti-Infecciosos , Infecções Bacterianas , COVID-19 , Nanopartículas Metálicas , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Bactérias/metabolismo , Cobre/metabolismo , Humanos , Íons/metabolismo , Íons/farmacologia , SARS-CoV-2 , Prata/metabolismo , Prata/farmacologia , Compostos de Prata/metabolismo , Compostos de Prata/farmacologia
3.
Nat Commun ; 13(1): 4258, 2022 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-35871068

RESUMO

Phocaeicola vulgatus is one of the most abundant and ubiquitous bacterial species of the human gut microbiota, yet a comprehensive analysis of antibacterial toxin production by members of this species has not been reported. Here, we identify and characterize a previously undescribed antibacterial protein. This toxin, designated BcpT, is encoded on a small mobile plasmid that is largely confined to strains of the closely related species Phocaeicola vulgatus and Phocaeicola dorei. BcpT is unusual in that it requires cleavage at two distinct sites for activation, and we identify bacterial proteases that perform this activation. We further identify BcpT's receptor as the Lipid A-core glycan, allowing BcpT to target species of other Bacteroidales families. Exposure of cells to BcpT induces a response involving an unusual sigma/anti-sigma factor pair that is likely triggered by cell envelope stress, resulting in the expression of genes that partially protect cells from multiple antimicrobial toxins.


Assuntos
Anti-Infecciosos , Proteínas de Bactérias , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Anti-Infecciosos/metabolismo , Bactérias/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Bacteroides , Bacteroidetes/genética , Humanos , Plasmídeos/genética
4.
Mar Drugs ; 20(7)2022 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-35877716

RESUMO

Two novel natural products, the polyketide cuniculene and the peptide antibiotic aquimarin, were recently discovered from the marine bacterial genus Aquimarina. However, the diversity of the secondary metabolite biosynthetic gene clusters (SM-BGCs) in Aquimarina genomes indicates a far greater biosynthetic potential. In this study, nine representative Aquimarina strains were tested for antimicrobial activity against diverse human-pathogenic and marine microorganisms and subjected to metabolomic and genomic profiling. We found an inhibitory activity of most Aquimarina strains against Candida glabrata and marine Vibrio and Alphaproteobacteria species. Aquimarina sp. Aq135 and Aquimarina muelleri crude extracts showed particularly promising antimicrobial activities, amongst others against methicillin-resistant Staphylococcus aureus. The metabolomic and functional genomic profiles of Aquimarina spp. followed similar patterns and were shaped by phylogeny. SM-BGC and metabolomics networks suggest the presence of novel polyketides and peptides, including cyclic depsipeptide-related compounds. Moreover, exploration of the 'Sponge Microbiome Project' dataset revealed that Aquimarina spp. possess low-abundance distributions worldwide across multiple marine biotopes. Our study emphasizes the relevance of this member of the microbial rare biosphere as a promising source of novel natural products. We predict that future metabologenomics studies of Aquimarina species will expand the spectrum of known secondary metabolites and bioactivities from marine ecosystems.


Assuntos
Anti-Infecciosos , Produtos Biológicos , Flavobacteriaceae , Staphylococcus aureus Resistente à Meticilina , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Bacteroidetes/genética , Produtos Biológicos/metabolismo , Produtos Biológicos/farmacologia , Ecossistema , Flavobacteriaceae/genética , Humanos , Metaboloma , Filogenia
5.
Metabolomics ; 18(7): 47, 2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35781167

RESUMO

BACKGROUND: The rise of antimicrobial resistance at an alarming rate is outpacing the development of new antibiotics. The worrisome trends of multidrug-resistant Gram-negative bacteria have enormously diminished existing antibiotic activity. Antibiotic treatments may inhibit bacterial growth or lead to induce bacterial cell death through disruption of bacterial metabolism directly or indirectly. In light of this, it is imperative to have a thorough understanding of the relationship of bacterial metabolism with antimicrobial activity and leverage the underlying principle towards development of novel and effective antimicrobial therapies. OBJECTIVE: Herein, we explore studies on metabolic analyses of Gram-negative pathogens upon antibiotic treatment. Metabolomic studies revealed that antibiotic therapy caused changes of metabolites abundance and perturbed the bacterial metabolism. Following this line of thought, addition of exogenous metabolite has been employed in in vitro, in vivo and in silico studies to activate the bacterial metabolism and thus potentiate the antibiotic activity. KEY SCIENTIFIC CONCEPTS OF REVIEW: Exogenous metabolites were discovered to cause metabolic modulation through activation of central carbon metabolism and cellular respiration, stimulation of proton motive force, increase of membrane potential, improvement of host immune protection, alteration of gut microbiome, and eventually facilitating antibiotic killing. The use of metabolites as antimicrobial adjuvants may be a promising approach in the fight against multidrug-resistant pathogens.


Assuntos
Anti-Infecciosos , Metabolômica , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Anti-Infecciosos/metabolismo , Bactérias/metabolismo , Bactérias Gram-Negativas
6.
Front Immunol ; 13: 910112, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35837407

RESUMO

Signaling lymphocytic activation molecule family 8 (SLAMF8) is involved in the negative modulation of NADPH oxidase activation. However, the impact of SLAMF8 downregulation on macrophage functionality and the microbicide mechanism remains elusive. To study this in depth, we first analyzed NADPH oxidase activation pathways in wild-type and SLAMF8-deficient macrophages upon different stimulus. Herein, we describe increased phosphorylation of the Erk1/2 and p38 MAP kinases, as well as increased phosphorylation of NADPH oxidase subunits in SLAMF8-deficient macrophages. Furthermore, using specific inhibitors, we observed that specific PI3K inhibition decreased the differences observed between wild-type and SLAMF8-deficient macrophages, stimulated with either PMA, LPS, or Salmonella typhimurium infection. Consequently, SLAMF8-deficient macrophages also showed increased recruitment of small GTPases such as Rab5 and Rab7, and the p47phox subunit to cytoplasmic Salmonella, suggesting an impairment of Salmonella-containing vacuole (SCV) progression in SLAMF8-deficient macrophages. Enhanced iNOS activation, NO production, and IL-6 expression were also observed in the absence of SLAMF8 upon Salmonella infection, either in vivo or in vitro, while overexpression of SLAMF8 in RAW264.7 macrophages showed the opposite phenotype. In addition, SLAMF8-deficient macrophages showed increased activation of Src kinases and reduced SHP-1 phosphate levels upon IFNγ and Salmonella stimuli in comparison to wild-type macrophages. In agreement with in vitro results, Salmonella clearance was augmented in SLAMF8-deficient mice compared to that in wild-type mice. Therefore, in conclusion, SLAMF8 intervention upon bacterial infection downregulates mouse macrophage activation, and confirmed that SLAMF8 receptor could be a potential therapeutic target for the treatment of severe or unresolved inflammatory conditions.


Assuntos
Anti-Infecciosos , Proteínas de Membrana/metabolismo , Infecções por Salmonella , Animais , Anti-Infecciosos/metabolismo , Macrófagos/metabolismo , Camundongos , NADPH Oxidases/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Infecções por Salmonella/metabolismo , Família de Moléculas de Sinalização da Ativação Linfocitária/genética
7.
Sci Rep ; 12(1): 10176, 2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35715695

RESUMO

Selective isolation of soil Actinobacteria was undertaken to isolate a new class of antibiotics and bioactive molecules. A Streptomyces sp. PSAA01 (= MTCC 13,157), isolated from soil of Eastern Himalaya foothill was cultivated on a large scale for the production of the antimicrobial SM02. It has been found that the maximum amount of SM02 produced while PSAA01 was grown in ISP-2 medium (pH 7.0) for 7 days at 30 °C in shaking (180 rpm) condition. A significant zone of inhibition against Staphylococcus aureus MTCC 96 has been found with the crude cell-free culture media (50 µL) of 7 days grown PSAA01. After the purification and chemical structural characterization, we found that SM02 is a new antimicrobial having 746 dalton molecular weight. The compound SM02 contains pyrimidine moiety in it and is produced by a species of Streptomyces and thus we have named this antibiotic pyrimidomycin. The antimicrobial spectrum of pyrimidomycin has been found to be restricted in Gram-positive organisms with a MIC of 12 µg/mL. SM02 was found active against Mycobacterium sp. and also multi-drug resistant Gram-positive bacteria with similar potency and found to disrupt the bacterial cell wall. Pyrimidomycin also showed significant impairment in the biofilm formation by S. aureus. Furthermore, pyrimidomycin showed synergy with the most used antibiotic like ampicillin, vancomycin and chloramphenicol. Pyrimidomycin did not have cytotoxicity towards human cell lines indicating its limited activity within bacteria.


Assuntos
Anti-Infecciosos , Streptomyces , Antibacterianos/metabolismo , Anti-Infecciosos/metabolismo , Humanos , Testes de Sensibilidade Microbiana , RNA Ribossômico 16S/metabolismo , Solo , Staphylococcus aureus/metabolismo , Streptomyces/metabolismo
8.
Curr Microbiol ; 79(8): 222, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35704212

RESUMO

Endophytes often inhabit plant tissues and cause no disease symptoms. Lasiodiplodia is generally considered a pathogenic fungus, but such a genus is capable of producing high-value bioactive molecules, such as enzymes, secondary metabolites including antimicrobials. Therefore, Lasiodiplodia sp. endophyte was cultivated in static mode for 12 days and EtOAc extracts were obtained and evaluated against pathogens afterward. Fermentation parameters (glucose, sucrose and NaNO3) were optimized by the factorial design and response surface methodology, as these are powerful tools to provide reliable information about fungal culture conditions and EtOAc extract yields were considered as response variables. Lasiodiplodia growth curve indicated that optimal production of EtOAc extract mass was achieved after 12 days of fermentation (284 mg 300 mL-1 broth), which is in agreement with values obtained from validation tests. Minimum Inhibitory Concentration (MIC) and Minimum Microbicidal Concentration (MMC) essays suggested that the endophyte produce substances presenting antimicrobial and antifungal activities against ATCC Staphylococcus aureus and Candida albicans strains at optimum point under evaluated conditions. MIC values ranged between 50 and 100 µg mL-1 for both pathogens, while MMC of C. albicans ranged from 100 to 200 µg mL-1, which evidence its fungicidal effect. Furthermore, it was found that the EtOAc extract yield can be increased by optimizing carbon and nitrogen sources in endophyte cultivation, and there was good agreement between predicted and experimental values under optimized conditions. Thus, Lasiodiplodia fungi are promising sources of antimicrobials and changes in carbon and nitrogen sources can improve the yield of secondary metabolites according to the factorial design.


Assuntos
Anti-Infecciosos , Ascomicetos , Acetatos , Antibacterianos/farmacologia , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Ascomicetos/metabolismo , Candida albicans , Carbono/metabolismo , Meios de Cultura/metabolismo , Endófitos/metabolismo , Testes de Sensibilidade Microbiana , Nitrogênio/metabolismo , Extratos Vegetais/metabolismo , Extratos Vegetais/farmacologia
9.
Clin Lab ; 68(6)2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35704732

RESUMO

BACKGROUND: Nowadays, novel antimicrobial strategies are being developed which focus on debilitating, rather than killing the microorganisms. In this regard, anti-biofilm therapy is one of the important ways to combat bacterial infections. Therefore, the aim of the current study was to evaluate the anti-biofilm activity of Carvacrol against E. faecalis by means of its effects on biofilm formation as well as on the gene expression levels of the two biofilm related genes, Epa and Esp. METHODS: A total of 40 clinical strains of E. faecalis were collected from three hospitals in Tehran, Iran during 2020. These isolates were confirmed by biochemical and genotypic methods. Antibacterial and anti-biofilm activity of Carvacrol essence were determined according the standard protocol. Finally, expression level of the biofilm related genes (Epa and Esp) were evaluated before and after the treatment with Carvacrol. RESULTS: A total of 14 isolates were considered as strong biofilm producers and were used for analysis. Carvacrol essence showed the best antibacterial activity at 2,500 µg/mL concentration against all the isolates, the biofilm formation capacity was decreased by Carvacrol essence, and it was statistically significant (p < 0.05). Expression levels of the Esp gene were decreased in 5 isolates while increased in 3 isolates following the Carvacrol treatment. Ex-pression levels of the EpaI gene was significantly decreased (p < 0.05) in 4 isolates following the Carvacrol treatment. CONCLUSIONS: In conclusion, the results presented in this study suggest that carvacrol extract exhibits significant antimicrobial and anti-biofilm properties against E. faecalis, even against vancomycin resistant isolates.


Assuntos
Anti-Infecciosos , Infecções por Bactérias Gram-Positivas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Anti-Infecciosos/uso terapêutico , Biofilmes , Cimenos , Enterococcus faecalis/genética , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Irã (Geográfico) , Testes de Sensibilidade Microbiana
10.
Microb Pathog ; 168: 105611, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35660509

RESUMO

As a potential anti-Helicobacter pylori agent, zinc causes impairment of Helicobacter pylori growth, and this property of zinc is of broad interest to biological investigators. However, little is known about the molecular mechanisms by which zinc inhibits the growth of Helicobacter pylori. Here, an in vitro experiment revealed that zinc at specific concentrations inhibits Helicobacter pylori growth. Furthermore, an RNA sequencing-based investigation of the global regulatory response to zinc revealed that exposure to zinc altered the Helicobacter pylori transcriptional profile in numerous ways. A high concentration of zinc induced the upregulation of genes related to ribosomal subunit, ribosome biosynthesis, chaperone and adhesins. However, flagellar assembly genes and some type IV secretion system genes were repressed. In addition, the expression levels of some genes that encode transporters of metal ions and that play key roles in Helicobacter pylori pathogenicity were altered under conditions of zinc-induced stress. In summary, high concentrations of zinc initiated antimicrobial activity to Helicobacter pylori under the combined effect of multiple repressed or altered pathogenetic genes and metabolic pathways associated with bacteria growth. This result has significant implications for understanding not only the antimicrobial activity mechanism of zinc but also the role of zinc-mediated homeostasis in Helicobacter pylori.


Assuntos
Anti-Infecciosos , Infecções por Helicobacter , Helicobacter pylori , Anti-Infecciosos/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Perfilação da Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Infecções por Helicobacter/microbiologia , Helicobacter pylori/efeitos dos fármacos , Transcriptoma , Zinco/farmacologia
11.
J Mater Chem B ; 10(27): 5129-5153, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35735175

RESUMO

Biofilms are formed at interfaces by microorganisms, which congregate in microstructured communities embedded in a self-produced extracellular polymeric substance (EPS). Biofilm-related infections are problematic due to the high resistance towards most clinically used antimicrobials, which is associated with high mortality and morbidity, combined with increased hospital stays and overall treatment costs. Several new nanotechnology-based approaches have recently been proposed for targeting resistant bacteria and microbial biofilms. Here we discuss the impacts of biofilms on healthcare, food processing and packaging, and water filtration and distribution systems, and summarize the emerging nanotechnological strategies that are being developed for biofilm prevention, control and eradication. Combination of novel nanomaterials with conventional antimicrobial therapies has shown great potential in producing more effective platforms for controlling biofilms. Recent developments include antimicrobial nanocarriers with enzyme surface functionality that allow passive infection site targeting, degradation of the EPS and delivery of high concentrations of antimicrobials to the residing cells. Several stimuli-responsive antimicrobial formulation strategies have taken advantage of the biofilm microenvironment to enhance interaction and passive delivery into the biofilm sites. Nanoparticles of ultralow size have also been recently employed in formulations to improve the EPS penetration, enhance the carrier efficiency, and improve the cell wall permeability to antimicrobials. We also discuss antimicrobial metal and metal oxide nanoparticle formulations which provide additional mechanical factors through externally induced actuation and generate reactive oxygen species (ROS) within the biofilms. The review helps to bridge microbiology with materials science and nanotechnology, enabling a more comprehensive interdisciplinary approach towards the development of novel antimicrobial treatments and biofilm control strategies.


Assuntos
Anti-Infecciosos , Matriz Extracelular de Substâncias Poliméricas , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Biofilmes , Matriz Extracelular de Substâncias Poliméricas/metabolismo , Nanotecnologia
12.
World J Microbiol Biotechnol ; 38(7): 114, 2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35578144

RESUMO

Burkholderia ambifaria T16 is a bacterium isolated from the rhizosphere of barley plants that showed a remarkable antifungal activity. This strain was also able to degrade fusaric acid (5-Butylpyridine-2-carboxylic acid) and detoxify this mycotoxin in inoculated barley seedlings. Genes and enzymes responsible for fusaric acid degradation have an important biotechnological potential in the control of fungal diseases caused by fusaric acid producers, or in the biodegradation/bio catalysis processes of pyridine derivatives. In this study, the complete genome of B. ambifaria T16 was sequenced and analyzed to identify genes involved in survival and competition in the rhizosphere, plant growth promotion, fungal growth inhibition, and degradation of aromatic compounds. The genomic analysis revealed the presence of several operons for the biosynthesis of antimicrobial compounds, such as pyrrolnitrin, ornibactin, occidiofungin and the membrane-associated AFC-BC11. These compounds were also detected in bacterial culture supernatants by mass spectrometry analysis. In addition, this strain has multiple genes contributing to its plant growth-promoting profile, including those for acetoin, 2,3-butanediol and indole-3-acetic acid production, siderophores biosynthesis, and solubilisation of organic and inorganic phosphate. A pan-genomic analysis demonstrated that the genome of strain T16 possesses large gene clusters that are absent in the genomes of B. ambifaria reference strains. According to predictions, most of these clusters would be involved in aromatic compounds degradation. One genomic region, encoding flavin-dependent monooxygenases of unknown function, is proposed as a candidate responsible for fusaric acid degradation.


Assuntos
Anti-Infecciosos , Complexo Burkholderia cepacia , Burkholderia , Micotoxinas , Anti-Infecciosos/metabolismo , Burkholderia/metabolismo , Complexo Burkholderia cepacia/genética , Ácido Fusárico/metabolismo , Genoma Bacteriano , Micotoxinas/metabolismo
13.
Microb Cell Fact ; 21(1): 77, 2022 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35527241

RESUMO

The growing emergence of microorganisms resistant to antibiotics has prompted the development of alternative antimicrobial therapies. Among them, the antimicrobial peptides produced by innate immunity, which are also known as host defense peptides (HDPs), hold great potential. They have been shown to exert activity against both Gram-positive and Gram-negative bacteria, including those resistant to antibiotics. These HDPs are classified into three categories: defensins, cathelicidins, and histatins. Traditionally, HDPs have been chemically synthesized, but this strategy often limits their application due to the high associated production costs. Alternatively, some HDPs have been recombinantly produced, but little is known about the impact of the bacterial strain in the recombinant product. This work aimed to assess the influence of the Escherichia coli strain used as cell factory to determine the activity and stability of recombinant defensins, which have 3 disulfide bonds. For that, an α-defensin [human α-defensin 5 (HD5)] and a ß-defensin [bovine lingual antimicrobial peptide (LAP)] were produced in two recombinant backgrounds. The first one was an E. coli BL21 strain, which has a reducing cytoplasm, whereas the second was an E. coli Origami B, that is a strain with a more oxidizing cytoplasm. The results showed that both HD5 and LAP, fused to Green Fluorescent Protein (GFP), were successfully produced in both BL21 and Origami B strains. However, differences were observed in the HDP production yield and bactericidal activity, especially for the HD5-based protein. The HD5 protein fused to GFP was not only produced at higher yields in the E. coli BL21 strain, but it also showed a higher quality and stability than that produced in the Origami B strain. Hence, this data showed that the strain had a clear impact on both HDPs quantity and quality.


Assuntos
Anti-Infecciosos , alfa-Defensinas , Animais , Antibacterianos/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/metabolismo , Bovinos , Escherichia coli/genética , Escherichia coli/metabolismo , Bactérias Gram-Negativas/metabolismo , Bactérias Gram-Positivas/metabolismo , Humanos , alfa-Defensinas/química , alfa-Defensinas/genética , alfa-Defensinas/farmacologia
14.
Front Immunol ; 13: 789366, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35493523

RESUMO

Local tissue acidosis affects anti-tumor immunity. In contrast, data on tissue pH levels in infected tissues and their impact on antimicrobial activity is sparse. In this study, we assessed the pH levels in cutaneous Leishmania lesions. Leishmania major-infected skin tissue displayed pH levels of 6.7 indicating that lesional pH is acidic. Next, we tested the effect of low extracellular pH on the ability of macrophages to produce leishmanicidal NO and to fight the protozoan parasite Leishmania major. Extracellular acidification led to a marked decrease in both NO production and leishmanicidal activity of lipopolysaccharide (LPS) and interferon γ (IFN-γ)-coactivated macrophages. This was not directly caused by a disruption of NOS2 expression, a shortage of reducing equivalents (NAPDH) or substrate (L-arginine), but by a direct, pH-mediated inhibition of NOS2 enzyme activity. Normalization of intracellular pH significantly increased NO production and antiparasitic activity of macrophages even in an acidic microenvironment. Overall, these findings indicate that low local tissue pH can curtail NO production and leishmanicidal activity of macrophages.


Assuntos
Anti-Infecciosos , Leishmania major , Anti-Infecciosos/metabolismo , Antiparasitários/metabolismo , Macrófagos , Óxido Nítrico/metabolismo
15.
BMC Biol ; 20(1): 114, 2022 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-35578204

RESUMO

BACKGROUND: Intracellularly active antimicrobial peptides are promising candidates for the development of antibiotics for human applications. However, drug development using peptides is challenging as, owing to their large size, an enormous sequence space is spanned. We built a high-throughput platform that incorporates rapid investigation of the sequence-activity relationship of peptides and enables rational optimization of their antimicrobial activity. The platform is based on deep mutational scanning of DNA-encoded peptides and employs highly parallelized bacterial self-screening coupled to next-generation sequencing as a readout for their antimicrobial activity. As a target, we used Bac71-23, a 23 amino acid residues long variant of bactenecin-7, a potent translational inhibitor and one of the best researched proline-rich antimicrobial peptides. RESULTS: Using the platform, we simultaneously determined the antimicrobial activity of >600,000 Bac71-23 variants and explored their sequence-activity relationship. This dataset guided the design of a focused library of ~160,000 variants and the identification of a lead candidate Bac7PS. Bac7PS showed high activity against multidrug-resistant clinical isolates of E. coli, and its activity was less dependent on SbmA, a transporter commonly used by proline-rich antimicrobial peptides to reach the cytosol and then inhibit translation. Furthermore, Bac7PS displayed strong ribosomal inhibition and low toxicity against eukaryotic cells and demonstrated good efficacy in a murine septicemia model induced by E. coli. CONCLUSION: We demonstrated that the presented platform can be used to establish the sequence-activity relationship of antimicrobial peptides, and showed its usefulness for hit-to-lead identification and optimization of antimicrobial drug candidates.


Assuntos
Anti-Infecciosos , Escherichia coli , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/farmacologia , Peptídeos Antimicrobianos , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Camundongos , Testes de Sensibilidade Microbiana , Peptídeos Cíclicos , Prolina/metabolismo
16.
Probiotics Antimicrob Proteins ; 14(4): 603-612, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35525881

RESUMO

Endolysins are bacteriophage-derived lytic enzymes with antimicrobial activity. The action of endolysins against Gram-negative bacteria remains a challenge due to the physical protection of the outer membrane. However, recent research has demonstrated that signal-anchor-release (SAR) endolysins permeate the outer membrane of Gram-negative bacteria. This study investigates 2628 putative endolysin genes identified in 183,298 bacteriophage genomes. Previously, bioinformatic approaches resulted in a database of 66 SAR endolysins. This manuscript almost doubles the list with 53 additional SAR endolysin candidates. Forty-eight of the putative SAR endolysins described in this study contained one muramidase catalytic domain, and five included additional cell wall-binding domains at the C-terminus. For the moment, SAR domains are found in four protein families: glycoside hydrolase family 19 (GH19), glycoside hydrolase family 24 (GH24), glycoside hydrolase family 25 (GH25), and glycoside hydrolase family 108 (GH108). These SAR lysis are clustered in eight groups based on biochemical properties and domain presence/absence. Therefore, in this study, we expand the arsenal of endolysin candidates that might act against Gram-negative bacteria and develop a consult database for antimicrobial proteins derived from bacteriophages.


Assuntos
Anti-Infecciosos , Bacteriófagos , Anti-Infecciosos/metabolismo , Bacteriófagos/genética , Bacteriófagos/metabolismo , Endopeptidases/química , Endopeptidases/genética , Glicosídeo Hidrolases/metabolismo , Bactérias Gram-Negativas , Metagenômica
17.
Biotechnol Adv ; 59: 107977, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35580750

RESUMO

While there are many opportunities to use microalgae as antimicrobial agents, little has been done to develop them beyond the characterization phase to the biotechnology phase. One challenge when screening microalgae for antimicrobial activity is their ability to synthesize biologically active secondary metabolites in response to environmental triggers. In order to identify potential strains with good antimicrobial activity and to advance the development of microalgae as antimicrobial agents, a rigorous scientific approach is required. Microalgae are most commonly screened for antimicrobial activity using the disc diffusion assay but this assay is problematic and produces false-positive and false-negative results. Quantitative minimum inhibitory concentration (MIC) values generated in assays such as the microdilution broth assay are more reproducible and enable comparison of results between research groups. For the present review, a dataset was compiled of published MIC values for microalgae. The Cyanobacteria and Chlorophyta were the best represented and other phyla were under represented. This data was used for assessment of factors influencing antimicrobial activity, including test microorganisms, microalgae taxonomy, different solvents for extraction and the growth phase at harvest. Activity was considered good if MIC values were < 1 mg/mL, moderate if MIC values were 1-8 mg/mL and weak with MIC >8.0 mg/mL. Areas requiring more research are discussed including screening a greater diversity of species in appropriate assays, reporting negative results, testing the culture supernatant for activity, synergistic effects and identifying antimicrobial compounds in the Chlorophyta. The potential for successful development and commercialization of microalgae antimicrobial agents will increase as more microalgae are screened and compounds identified.


Assuntos
Anti-Infecciosos , Clorófitas , Microalgas , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Bioprospecção , Microalgas/metabolismo
18.
Food Chem ; 391: 133261, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35640336

RESUMO

Discovery of new selective anticancer, anti-inflammatory, and anti-microbial agents is a crucial and necessary step to ensure a pipeline for innovative products to improve disease management. Several new bioactive agents derived from plants have been investigated and an example is the steroidal glycoalkaloid (SGA) class of natural products found in plants, investigated for their health-beneficial biological activities. Among them, α-tomatine is a SGA derived from the plant parts of unripe green tomatoes. In this review we aimed at searching for two different perspectives to study α-tomatine from green tomatoes, namely from its dual action point of view: as an anti-nutrient and as a health promoter. The aspects associated to its synthesis and degradation were considered. Finally, the current strategies for its extraction from natural sources and the methodologies commonly used for its identification and quantification were discussed.


Assuntos
Anti-Infecciosos , Lycopersicon esculentum , Anti-Infecciosos/metabolismo , Anti-Inflamatórios/metabolismo , Humanos , Lycopersicon esculentum/metabolismo , Tomatina/análogos & derivados , Tomatina/metabolismo
19.
Front Immunol ; 13: 867630, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35464433

RESUMO

Erythroferrone is a recently identified erythroid regulator produced by erythroblasts in the mammalian bone marrow and extramedullary sites, known to be induced in conditions of anemia or blood loss. Iron metabolism is affected by erythroferrone through its capacity to inhibit hepcidin production, leading to the increase of iron availability required for erythropoiesis. However, little is known about erythroferrone function in other vertebrates, in particular teleost fish, that unlike mammals, present two different functional types of hepcidin, one type mostly involved in iron metabolism and the other in antimicrobial response. The study of erythroferrone evolution and its biological role in teleost fish can give us valuably new insights into its function. To address these questions, we characterized erythroferrone in the European sea bass (Dicentrarchus labrax), a species presenting two hepcidin types, and evaluated variations in its expression levels in response to different experimental conditions. During experimental anemia, erythroferrone responds by increasing its expression and suppressing hepcidin production, following the pattern observed in mammals, but it is not influenced by iron overload. However, during bacterial infection, erythroferrone is downregulated and hepcidin levels increase. Furthermore, administration of Hamp1 but not of Hamp2 peptides suppresses erythroferrone expression. In conclusion, in dual hepcidin teleost fish erythroferrone seems to only interact with type 1 hepcidin, known to be involved in iron homeostasis, but not with type 2, which has an almost exclusive antimicrobial role.


Assuntos
Anemia , Anti-Infecciosos , Bass , Anemia/metabolismo , Animais , Anti-Infecciosos/metabolismo , Bass/microbiologia , Hepcidinas/metabolismo , Ferro/metabolismo , Mamíferos/metabolismo
20.
Sci Rep ; 12(1): 5865, 2022 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-35440606

RESUMO

Rampant rise of multidrug resistant strains among Gram-negative bacteria has necessitated investigation of alternative antimicrobial agents with novel modes of action including antimicrobial proteins such as bacteriocins. The main hurdle in the clinical development of bacteriocin biologics is their narrow specificity and limited strain activity spectrum. Genome mining of bacteria for broadly active bacteriocins have identified a number of promising candidates but attempts to improve these natural multidomain proteins further, for example by combining domains of different origin, have so far met with limited success. We have found that domain swapping of Pseudomonas bacteriocins of porin type, when carried out between phylogenetically related molecules with similar mechanism of activity, allows the generation of highly active molecules with broader spectrum of activity, for example by abolishing strain resistance due to the presence of immunity proteins. The most broadly active chimera engineered in this study, S5-PmnH, exhibits excellent control of Pseudomonas aeruginosa infection in validated murine keratitis and lung infection models.


Assuntos
Anti-Infecciosos , Bacteriocinas , Ceratite , Infecções por Pseudomonas , Animais , Antibacterianos/farmacologia , Anti-Infecciosos/metabolismo , Bacteriocinas/genética , Bacteriocinas/metabolismo , Bacteriocinas/farmacologia , Quimera/metabolismo , Ceratite/tratamento farmacológico , Pulmão/metabolismo , Camundongos , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo
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