RESUMO
Serratia marcescens is a bacterial species that produces an antibacterial pigment (Prodigiosin) showing a wide adaptive response to environmental stresses. The study aimed to investigate Prodigiosin production in S. marcescens wild-type strains, as well as its relation to photoprotection and antigenotoxicity against UVB. Prodigiosin yield was spectrophotometrically assayed in extracts of bacterial strains grown in different culture media. In vitro photoprotection efficacy was evaluated using the in vitro indices sun protection factor (SPFin vitro ) and critical wavelength (λc). The percentage of UVB antigenotoxicity estimates (%GI) in the SOS Chromotest was also evaluated. Correlation analysis was used to examine the relationship between Prodigiosin yield, SPFin vitro , %GI estimates and environmental traits (altitude, temperature, rainfall and solar irradiance). Prodigiosin yield in S. marcescens strains varied depending on culture media used for its growth, and it was correlated with environmental variables such as temperature and solar irradiance. SPFin vitro estimates were well correlated with Prodigiosin concentration and %GI values in the bacterial strains being studied. UVB photoprotective efficacy of the extracts obtained from S. marcescens strains depends on the strain's Prodigiosin yield and its antigenotoxic potential. The extracts with Prodigiosin yield higher than ~17 µg mL-1 could be used as sources of sunscreen ingredients.
Assuntos
Prodigiosina , Serratia marcescens , Colômbia , Meios de Cultura , Extratos Vegetais , Prodigiosina/farmacologia , Serratia marcescens/fisiologiaRESUMO
A plethora of bacteria-fungal interactions occur on the extended fungal hyphae network in soil. The mycosphere of saprophytic fungi can serve as a bacterial niche boosting their survival, dispersion, and activity. Such ecological concepts can be converted to bioproducts for sustainable agriculture. Accordingly, we tested the hypothesis that the well-characterised beneficial bacterium Serratia marcescens UENF-22GI can enhance plant growth-promoting properties when combined with Trichoderma longibrachiatum UENF-F476. The cultural and cell interactions demonstrated S. marcescens and T. longibrachiatum mutual compatibility. Bacteria cells were able to attach, forming aggregates to biofilms and migrating through the fungal hyphae network. Long-distance bacterial migration through growing hyphae was confirmed using a two-compartment Petri dishes assay. Fungal inoculation increased the bacteria survival rates into the vermicompost substrate over the experimental time. Also, in vitro indolic compound, phosphorus, and zinc solubilisation bacteria activities increased in the presence of the fungus. In line with the ecophysiological bacteria fitness, the bacterium-fungal combination boosted tomato and papaya plantlet growth when applied into the plant substrate under nursery conditions. Mutualistic interaction between mycosphere-colonizing bacterium S. marcescens UENF-22GI and the saprotrophic fungi T. longibrachiatum UENF-F467 increased the ecological fitness of the bacteria alongside with beneficial potential for plant growth. A proper combination and delivery of mutual compatible beneficial bacteria-fungal represent an open avenue for microbial-based products for the biological enrichment of plant substrates in agricultural systems.
Assuntos
Carica/crescimento & desenvolvimento , Hypocreales/fisiologia , Serratia marcescens/fisiologia , Microbiologia do Solo , Solanum lycopersicum/crescimento & desenvolvimento , Biofilmes , Carica/microbiologia , Hifas/fisiologia , Solanum lycopersicum/microbiologia , Plântula/crescimento & desenvolvimento , Plântula/microbiologiaRESUMO
BACKGROUND: Serratia marcescens becomes an apparent nosocomial pathogen and causes a variety of infections. S. marcescens possess various virulence factors that are regulated by intercellular communication system quorum sensing (QS). Targeting bacterial virulence is a proposed strategy to overcome bacterial resistance. Sitagliptin anti-QS activity has been demonstrated previously and we aimed in this study to investigate the effects of antidiabetic drugs vildagliptin and metformin compared to sitagliptin on S. marcescens pathogenesis. METHODS: We assessed the effects of tested drugs in subinhibitory concentrations phenotypically on the virulence factors and genotypically on the virulence encoding genes' expressions. The protection of tested drugs on S. marcescens pathogenesis was performed in vivo. Molecular docking study has been conducted to evaluate the interference capabilities of tested drugs to the SmaR QS receptor. RESULTS: Vildagliptin reduced the expression of virulence encoding genes but did not show in vitro or in vivo anti-virulence activities. Metformin reduced the expression of virulence encoding genes and inhibited bacterial virulence in vitro but did not show in vivo protection. Sitagliptin significantly inhibited virulence factors in vitro, reduced the expression of virulence factors and protected mice from S. marcescens. Docking study revealed that sitagliptin is more active than metformin and fully binds to SmaR receptor, whereas vildagliptin had single interaction to SmaR. CONCLUSION: The downregulation of virulence genes was not enough to show anti-virulence activities. Hindering of QS receptors may play a crucial role in diminishing bacterial virulence.
Assuntos
Antibacterianos/farmacologia , Reposicionamento de Medicamentos , Hipoglicemiantes/farmacologia , Infecções por Serratia/tratamento farmacológico , Serratia marcescens/efeitos dos fármacos , Animais , Antibacterianos/química , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Humanos , Hipoglicemiantes/química , Metformina/química , Metformina/farmacologia , Camundongos , Simulação de Acoplamento Molecular , Infecções por Serratia/microbiologia , Serratia marcescens/genética , Serratia marcescens/patogenicidade , Serratia marcescens/fisiologia , Vildagliptina/química , Vildagliptina/farmacologia , Virulência/efeitos dos fármacos , Fatores de Virulência/química , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
In nature, microorganisms often exhibit competitive behavior for nutrients and limited space, allowing them to alter the virulence determinants of pathogens. The human pathogenic yeast Cryptococcus neoformans can be found organized in biofilms, a complex community composed of an extracellular matrix which confers protection against predation. The aim of this study was to evaluate and characterize antagonistic interactions between two cohabiting microorganisms: C. neoformans and the bacteria Serratia marcescens. The interaction of S. marcescens with C. neoformans expressed a negative effect on biofilm formation, polysaccharide capsule, production of urease, and melanization of the yeast. These findings evidence that competition in mixed communities can result in dominance by one species, with direct impact on the physiological modulation of virulence determinants. Such an approach is key for understating the response of communities to the presence of competitors and, ultimately, rationally designing communities to prevent and treat certain diseases.
Assuntos
Biofilmes , Cryptococcus neoformans , Interações Microbianas , Serratia marcescens , Cryptococcus neoformans/patogenicidade , Cryptococcus neoformans/fisiologia , Interações Microbianas/fisiologia , Serratia marcescens/patogenicidade , Serratia marcescens/fisiologia , Fatores de Virulência/metabolismoRESUMO
Serratia marcescens is a γ-Proteobacterium and an opportunistic animal and insect pathogen. The bacterium exhibits a complex extracellular protein 'secretome' comprising numerous enzymes, toxins and effector molecules. One component of the secretome is the 'chitinolytic machinery', which is a set of at least four chitinases that allow the use of insoluble extracellular chitin as sole carbon source. Secretion of the chitinases across the outer membrane is governed by the chiWXYZ operon encoding a holin/endopeptidase pair. Expression of the chiWXYZ operon is co-ordinated with the chitinase genes and is also bimodal, as normally only 1% of the population expresses the chitinolytic machinery. In this study, the role of the ChiR protein in chitinase production has been explored. Using live cell imaging and flow cytometry, ChiR was shown to govern the co-ordinated regulation of chiWXYZ with both chiA and chiC. Moreover, overexpression of chiR alone was able to increase the proportion of the cell population expressing chitinase genes to >60â%. In addition, quantitative label-free proteomic analysis of cells overexpressing chiR established that ChiR regulates the entire chitinolytic machinery. The proteomic experiments also revealed a surprising link between the regulation of the chitinolytic machinery and the production of proteins involved in the metabolism of nitrogen compounds such as nitrate and nitrite. The research demonstrates for the first time that ChiR plays a critical role in controlling bimodal gene expression in S. marcescens, and provides new evidence of a clear link between chitin breakdown and nitrogen metabolism.
Assuntos
Proteínas de Bactérias/metabolismo , Quitinases/metabolismo , Serratia marcescens/fisiologia , Proteínas de Bactérias/genética , Quitinases/genética , Citometria de Fluxo , Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Microscopia de Fluorescência , Mutação , Compostos de Nitrogênio/metabolismo , Óperon , Proteômica , Serratia marcescens/genética , Serratia marcescens/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Capsicum peppers have not been investigated as sources of quorum sensing (QS) inhibitors. This study aimed to identify compounds in pimenta-malagueta (Capsicum frutescens) and red pepper (Capsicum annuum) extracts and to evaluate their effect on violacein production in Chromobacterium violaceum ATCC 12472 and C. violaceum CV026, as well as biofilm formation (BF) in Pseudomonas aeruginosa PAO1 and Serratia marcescens MG1. Among the extracts, pimenta-malagueta methanolic extract (PMME) was chosen because it contained capsaicin, dihydrocapsaicin, and luteolin in greater amount than the other extracts. In general, PMME partially inhibited bacterial growth at 2.5 and 5.0 mg/mL, as well as capsaicin at 100 µg/mL and luteolin at 62.5, 125, and 250 µg/mL. At lower concentrations, PMME and luteolin reduced violacein production in C. violaceum ATCC 12472 without affecting growth, a result that was not observed with capsaicin. We show that violacein inhibition by PMME is likely due to luteolin. In silico docking evaluation showed that luteolin binds to the CviR QS regulator. Crystal violet staining and confocal microscopy revealed that BF was increased by PMME and capsaicin, being remarkably superior for P. aeruginosa PAO1 at 30 °C. Capsaicin is not an effective QS inhibitor, while luteolin should be further investigated for its potential effects in QS regulated phenotypes. PRACTICAL APPLICATION: Quorum sensing (QS) is a form of bacterial communication targeted for studies aiming to inhibit bacterial virulence. QS regulates phenotypes that influence microbial activities across many areas, including Food Science. Capsicum frutescens is a type of chili pepper consumed in Brazil, rich in bioactive compounds such as capsaicin (which gives its pungency) and luteolin (a phenolic compound). We show that C. frutescens extract and luteolin inhibit QS in a model bacterium, along with the possible molecular mechanism of inhibition. Capsaicin did not inhibit QS neither biofilm formation. Luteolin should be further investigated for its QS inhibition properties and biotechnological applications.
Assuntos
Capsaicina/farmacologia , Capsicum/química , Luteolina/farmacologia , Extratos Vegetais/farmacologia , Percepção de Quorum/efeitos dos fármacos , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Brasil , Capsaicina/análogos & derivados , Capsaicina/análise , Chromobacterium/efeitos dos fármacos , Frutas/química , Luteolina/análise , Fenótipo , Extratos Vegetais/química , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Serratia marcescens/efeitos dos fármacos , Serratia marcescens/fisiologiaRESUMO
BACKGROUND: Plant-bacteria associations have been extensively studied for their potential in increasing crop productivity in a sustainable manner. Serratia marcescens is a species of Enterobacteriaceae found in a wide range of environments, including soil. RESULTS: Here we describe the genome sequencing and assessment of plant growth-promoting abilities of S. marcescens UENF-22GI, a strain isolated from mature cattle manure vermicompost. In vitro, S. marcescens UENF-22GI is able to solubilize P and Zn, to produce indole compounds (likely IAA), to colonize hyphae and counter the growth of two phytopathogenic fungi. Inoculation of maize with this strain remarkably increased seedling growth and biomass under greenhouse conditions. The S. marcescens UENF-22GI genome has 5 Mb, assembled in 17 scaffolds comprising 4662 genes (4528 are protein-coding). No plasmids were identified. S. marcescens UENF-22GI is phylogenetically placed within a clade comprised almost exclusively of non-clinical strains. We identified genes and operons that are likely responsible for the interesting plant-growth promoting features that were experimentally described. The S. marcescens UENF-22GI genome harbors a horizontally-transferred genomic island involved in antibiotic production, antibiotic resistance, and anti-phage defense via a novel ADP-ribosyltransferase-like protein and possible modification of DNA by a deazapurine base, which likely contributes to its competitiveness against other bacteria. CONCLUSIONS: Collectively, our results suggest that S. marcescens UENF-22GI is a strong candidate to be used in the enrichment of substrates for plant growth promotion or as part of bioinoculants for agriculture.
Assuntos
Compostagem , Genoma Bacteriano/genética , Serratia marcescens/genética , Serratia marcescens/fisiologia , Zea mays/crescimento & desenvolvimento , Zea mays/microbiologia , Biofilmes , Transporte Biológico/genética , Biomassa , Fusarium/crescimento & desenvolvimento , Transferência Genética Horizontal , Esterco/microbiologia , Controle Biológico de Vetores , Fenóis/metabolismo , Fósforo/química , Fósforo/metabolismo , Serratia marcescens/isolamento & purificação , Serratia marcescens/metabolismo , Solubilidade , Espermidina/biossíntese , Zinco/química , Zinco/metabolismoRESUMO
Corals harbor a wide diversity of bacteria associated with their mucus. These bacteria can play an important role in nutrient cycling, degradation of xenobiotics and defense against pathogens by producing antimicrobial compounds. However, the diversity of the cultivable heterotrophic bacteria, especially in the Brazilian coral species, remains poorly understood. The present work compares the diversity of cultivable bacteria isolated from the mucus and surrounding environments of four coral species present along the Brazilian coast, and explores the antibacterial activity of these bacteria. Bacteria belonging to the phyla Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes were isolated. The mucus environment presented a significantly different bacteria composition, compared to the water and sediment environments, with high abundance of Alcanivorax, Acinetobacter, Aurantimonas and Erythrobacter. No difference in the inhibition activity was found between the isolates from mucus and from the surrounding environment. Eighty-three per cent of the bacteria isolated from the mucus presented antimicrobial activity against Serratia marcescens, an opportunistic coral pathogen, suggesting that they might play a role in maintaining the health of the host. Most of the bacteria isolates that presented positive antimicrobial activity belonged to the genus Bacillus.
Assuntos
Antozoários/microbiologia , Antibiose , Bacillus/fisiologia , Microbiota/fisiologia , Água do Mar/microbiologia , Serratia marcescens/fisiologia , Acinetobacter/classificação , Acinetobacter/genética , Acinetobacter/isolamento & purificação , Acinetobacter/fisiologia , Actinobacteria/classificação , Actinobacteria/genética , Actinobacteria/isolamento & purificação , Actinobacteria/fisiologia , Alcanivoraceae/classificação , Alcanivoraceae/genética , Alcanivoraceae/isolamento & purificação , Alcanivoraceae/fisiologia , Animais , Bacillus/classificação , Bacillus/genética , Bacillus/isolamento & purificação , Brasil , Variação Genética , Processos Heterotróficos , Filogenia , RNA Ribossômico 16S/genética , Estações do Ano , Sphingomonadaceae/classificação , Sphingomonadaceae/genética , Sphingomonadaceae/isolamento & purificação , Sphingomonadaceae/fisiologiaRESUMO
AIMS: To evaluate the antibiofilm potential of water-soluble Moringa oleifera seed lectin (WSMoL) on Serratia marcescens and Bacillus sp. METHODS AND RESULTS: WSMoL inhibited biofilm formation by S. marcescens at concentrations lower than 2·6 µg ml-1 and impaired bacterial growth at higher concentrations, avoiding biofilm formation. For Bacillus sp., the lectin inhibited bacterial growth at all concentrations. The antibiofilm action of WSMoL is associated with damage to bacterial cells. WSMoL did not disrupt preformed S. marcescens biofilms but was able to damage cells inside them. On the other hand, the lectin reduced the number of cells in Bacillus sp. biofilm treated with it. WSMoL was able to control biofilm formation when immobilized on glass surface (116 µg cm-2 ), damaging S. marcescens cells and avoiding adherence of Bacillus sp. cells on glass. The Bacillus sp. isolate is member of Bacillus subtilis species complex and closely related to species of the conspecific 'amyloliquefaciens' group. CONCLUSION: WSMoL prevented biofilm development by S. marcescens and Bacillus sp. and the antibiofilm effect is also observed when the lectin is immobilized on glass. SIGNIFICANCE AND IMPACT OF THE STUDY: Taking together, our results provide support to the potential use of WSMoL for controlling biofilm formation by bacteria.
Assuntos
Antibacterianos/farmacologia , Bacillus/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Lectinas/farmacologia , Moringa oleifera/química , Extratos Vegetais/farmacologia , Serratia marcescens/efeitos dos fármacos , Antibacterianos/isolamento & purificação , Bacillus/fisiologia , Lectinas/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Sementes/química , Serratia marcescens/fisiologiaRESUMO
The induction of DNA synthesis in various tissues of Anopheles albimanus, in response to challenge with Saccharomyces cerevisiae, Micrococcus luteus, and Serratia marcescens, was analyzed by 5-bromo-2-deoxy-uridine (BrdU) incorporation. Microorganism-inoculated mosquitoes were fed with a sucrose solution containing BrdU and maintained alive for 5 days. Alternatively, abdominal carcasses of microorganisms-inoculated mosquitoes were cultivated in Roswell Park Memorial Institute (RPMI) medium supplemented with BrdU for 5 days. Control groups were inoculated with RPMI alone. In both experiments, DNA synthesis, evidenced by epifluorescence with an anti-BrdU fluorescein-labeled antibody, occurred in fat body, epithelial cells of pleural membranes, dorsal vessel, and the oviducts. Relative quantification of DNA synthesis, evaluated by ELISA using an anti-BrdU peroxidase-labeled antibody, was higher in abdomen tissues of microorganisms-inoculated mosquitoes than controls in in vitro and in vivo experiments. The intensity of DNA synthesis varied among the different microorganism challenges, but was higher in in vivo experiments, compared to cultured samples. These differences in DNA synthesis suggest a compartmentalization of the immune response, probably mediated by different signaling pathways.
Assuntos
Anopheles/imunologia , Anopheles/metabolismo , DNA/biossíntese , Animais , Anopheles/genética , Anopheles/microbiologia , Bromodesoxiuridina/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Imunofluorescência , Micrococcus luteus/fisiologia , Especificidade de Órgãos , Saccharomyces cerevisiae/fisiologia , Serratia marcescens/fisiologia , Especificidade da EspécieRESUMO
In insects, a rapid and massive synthesis of antimicrobial peptides (AMPs) is activated through signaling pathways (Toll and Imd) to combat invading microbial pathogens. However, it is still unclear whether different types of bacteria provoke specific responses. Immune response mechanisms and the activation of specific genes were investigated by challenging Apis mellifera workers with the Gram-negative bacterium Serratia marcescens or the Gram-positive bacterium Micrococcus luteus. The immune system responded by activating most genes of the Toll and Imd pathways, particularly AMP genes. However, genes specifically regulated by M. luteus or S. marcescens were not detected, suggesting an interaction between the signaling pathways that lead to immune effectors synthesis. Despite this finding, kappaB motifs in the 5'-UTRs of selected genes suggest a pathway-specific control of AMP and transferrin-1 gene expression. Regulation by miRNAs was also investigated and revealed a number of candidates for the post-transcriptional regulation of immune genes in bees.
Assuntos
Abelhas/microbiologia , Abelhas/fisiologia , Regulação da Expressão Gênica , Micrococcus luteus/fisiologia , Serratia marcescens/fisiologia , Animais , Abelhas/genética , Abelhas/imunologia , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , MicroRNAs/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transferrina/genética , Transferrina/metabolismoRESUMO
The potential of three Serratia marcescens strains (CFFSUR-B2, CFFSUR-B3 and CFFSUR-B4) isolated from tropical regions in Mexico to inhibit the mycelial growth and conidial germination of Colletotrichum gloeosporioides, causal agent of fruit anthracnose, was evaluated. The ability of these strains to produce prodigiosin and chitinases when cultivated in oil seed-based media (peanut, sesame, soybean and castor bean) and in Luria-Bertani medium was determined. All of the strains exhibited similar fungal antagonistic activities and inhibited myceliar growth by more than 40% while inhibiting conidial germination by 81-89% (P = 0.01). The highest level of prodigiosin (40 µg/ml) was produced in the peanut-based medium while growth in soybean-based medium allowed the highest production of chitinases (56 units/ml), independent of the strain used. Strain CFFSUR-B2 grown in peanut medium was used to evaluate the effect of inoculum density and initial pH on metabolite production. The amount of prodigiosin produced increased with greater inoculum densities, with an initial density of 1 × 10(12) resulting in the highest production (60 µg/ml). Prodigiosin production was not affected by pH. The strains studied have the advantage of being adapted to tropical climates and are able to produce chitinases in the absence of chitin induction in vitro. These characteristics suggest their potential as biocontrol agents for fungal pathogens in tropical regions of the world.
Assuntos
Agentes de Controle Biológico , Quitinases/biossíntese , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Prodigiosina/biossíntese , Serratia marcescens/fisiologia , Proteínas de Bactérias/biossíntese , Sequência de Bases , Carica/microbiologia , Colletotrichum/patogenicidade , Meios de Cultura , DNA Girase/genética , DNA Bacteriano/genética , Frutas/microbiologia , Genes Bacterianos , Mangifera/microbiologia , México , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Serratia marcescens/genética , Serratia marcescens/isolamento & purificação , Clima TropicalRESUMO
Insects are able to combat infection by initiating an efficient immune response that involves synthesizing antimicrobial peptides and a range of other defense molecules. These responses may be costly to the organism, resulting in it exploiting endogenous resources to maintain homeostasis or support defense to the detriment of other physiological needs. We used queenless worker bees on distinct dietary regimes that may alter hemolymph protein storage and ovary activation to investigate the physiological costs of infection with Serratia marcescens. The expression of the genes encoding the storage proteins vitellogenin and hexamerin 70a, the vitellogenin receptor, and vasa (which has a putative role in reproduction), was impaired in the infected bees. This impairment was mainly evident in the bees fed beebread, which caused significantly higher expression of these genes than did royal jelly or syrup, and this was confirmed at the vitellogenin and hexamerin 70a protein levels. Beebread was also the only diet that promoted ovary activation in the queenless bees, but this activation was significantly impaired by the infection. The expression of the genes encoding the storage proteins apolipophorins-I and -III and the lipophorin receptor was not altered by infection regardless the diet provided to the bees. Similarly, the storage of apolipophorin-I in the hemolymph was only slightly impaired by the infection, independently of the supplied diet. Taken together these results indicate that, infection demands a physiological cost from the transcription of specific protein storage-related genes and from the reproductive capacity.
Assuntos
Abelhas/metabolismo , Interações Hospedeiro-Patógeno , Proteínas de Insetos/metabolismo , Animais , Abelhas/genética , Abelhas/microbiologia , Dieta , Feminino , Ovário/fisiologia , Reprodução , Infecções por Serratia/metabolismo , Serratia marcescens/fisiologiaRESUMO
Phlebotomine sand flies are the vectors of medically important Leishmania. The Leishmania protozoa reside in the sand fly gut, but the nature of the immune response to the presence of Leishmania is unknown. Reactive oxygen species (ROS) are a major component of insect innate immune pathways regulating gut-microbe homeostasis. Here we show that the concentration of ROS increased in sand fly midguts after they fed on the insect pathogen Serratia marcescens but not after feeding on the Leishmania that uses the sand fly as a vector. Moreover, the Leishmania is sensitive to ROS either by oral administration of ROS to the infected fly or by silencing a gene that expresses a sand fly ROS-scavenging enzyme. Finally, the treatment of sand flies with an exogenous ROS scavenger (uric acid) altered the gut microbial homeostasis, led to an increased commensal gut microbiota, and reduced insect survival after oral infection with S. marcescens. Our study demonstrates a differential response of the sand fly ROS system to gut microbiota, an insect pathogen, and the Leishmania that utilize the sand fly as a vehicle for transmission between mammalian hosts.
Assuntos
Imunidade/imunologia , Leishmania mexicana/imunologia , Psychodidae/imunologia , Espécies Reativas de Oxigênio/imunologia , Serratia marcescens/imunologia , Sequência de Aminoácidos , Animais , Antioxidantes/administração & dosagem , Antioxidantes/farmacologia , Catalase/classificação , Catalase/genética , Catalase/metabolismo , Feminino , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/parasitologia , Técnicas de Inativação de Genes , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Interações Hospedeiro-Patógeno/imunologia , Peróxido de Hidrogênio/metabolismo , Imunidade/efeitos dos fármacos , Proteínas de Insetos/classificação , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Insetos Vetores/imunologia , Insetos Vetores/microbiologia , Insetos Vetores/parasitologia , Leishmania mexicana/fisiologia , Dados de Sequência Molecular , Peroxirredoxinas/classificação , Peroxirredoxinas/genética , Peroxirredoxinas/metabolismo , Filogenia , Psychodidae/enzimologia , Psychodidae/genética , Espécies Reativas de Oxigênio/metabolismo , Homologia de Sequência de Aminoácidos , Serratia marcescens/fisiologia , Superóxido Dismutase/classificação , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Ácido Úrico/administração & dosagem , Ácido Úrico/farmacologiaRESUMO
Serratia marcescens is an opportunistic human pathogen that represents a growing problem for public health, particularly in hospitalized or immunocompromised patients. However, little is known about factors and mechanisms that contribute to S. marcescens pathogenesis within its host. In this work, we explore the invasion process of this opportunistic pathogen to epithelial cells. We demonstrate that once internalized, Serratia is able not only to persist but also to multiply inside a large membrane-bound compartment. This structure displays autophagic-like features, acquiring LC3 and Rab7, markers described to be recruited throughout the progression of antibacterial autophagy. The majority of the autophagic-like vacuoles in which Serratia resides and proliferates are non-acidic and have no degradative properties, indicating that the bacteria are capable to either delay or prevent fusion with lysosomal compartments, altering the expected progression of autophagosome maturation. In addition, our results demonstrate that Serratia triggers a non-canonical autophagic process before internalization. These findings reveal that S. marcescens is able to manipulate the autophagic traffic, generating a suitable niche for survival and proliferation inside the host cell.
Assuntos
Autofagia , Serratia marcescens/fisiologia , Vacúolos/microbiologia , Cloreto de Amônio/farmacologia , Androstadienos/farmacologia , Animais , Células CHO , Linhagem Celular , Cricetinae , Células Epiteliais/microbiologia , Técnica Indireta de Fluorescência para Anticorpo , Gentamicinas/farmacologia , Humanos , Macrolídeos/farmacologia , Microscopia Confocal , Serratia marcescens/efeitos dos fármacos , WortmaninaRESUMO
This report provides the first account of the pathological changes associated with infection by Serratia marcescens in an adult male axolotl. The infection resulted in septicaemia with severe multifocal necrotizing myocarditis. The latter lesion evolved to cardiac rupture, haemopericardium and death resulting from cardiac tamponade. This animal was exposed to higher than usual temperatures (24-25 °C) 2 weeks before the onset of disease and this may have resulted in immunocompromise and opportunistic bacterial infection. S. marcescens was isolated from the coelomic and pericardial cavity. Both isolates were identical and were resistant to ß-lactam antibiotics, but not to aminoglycosides or fluoroquinolones. The production of red prodigiosin pigment by the bacterium suggested an environmental origin. Overall, the clinical and histopathological presentation suggests that S. marcescens should be included in the list of aetiological agents of the 'red-leg'/bacterial dermatosepticaemia syndrome of amphibians.
Assuntos
Ambystoma mexicanum , Miocardite/veterinária , Infecções por Serratia/veterinária , Serratia marcescens/isolamento & purificação , Animais , Miocardite/microbiologia , Miocardite/patologia , Necrose , Infecções por Serratia/patologia , Serratia marcescens/fisiologiaRESUMO
In this paper, the lytic activity of two variants of Serratia marcescens against promastigotes of Leishmania braziliensis was studied. In vitro assays showed that S. marcescens variant SM365 lyses L. braziliensis promastigotes, while the variant DB11 did not. Scanning electron microscopy (SEM) revealed that S. marcescens SM365 adheres to all cellular body and flagellum of the parasite. Several filamentous structures were formed and identified as biofilms. After 120min incubation, they connect the protozoan to the developing bacterial clusters. SEM also demonstrated that bacteria, adhered onto L. braziliensis promastigote surface, formed small filamentous structures which apparently penetrates into the parasite membrane. d-mannose protects L. braziliensis against the S. marcescens SM365 lytic effect in a dose dependent manner. SM365 variant pre cultivated at 37 degrees C did not synthesize prodigiosin although the adherence and lysis of L. braziliensis were similar to the effect observed with bacteria cultivated at 28 degrees C, which produce high concentrations of prodigiosin. Thus, we suggest that prodigiosin is not involved in the lysis of promastigotes and that adherence promoted by bacterial mannose-sensitive (MS) fimbriae is a determinant factor in the lysis of L. braziliensis by S. marcescens SM365.
Assuntos
Fímbrias Bacterianas/metabolismo , Leishmania braziliensis/metabolismo , Prodigiosina/metabolismo , Serratia marcescens/fisiologia , Animais , Aderência Bacteriana , Carboidratos/farmacologia , Fímbrias Bacterianas/efeitos dos fármacos , Cinética , Leishmania braziliensis/efeitos dos fármacos , Leishmania braziliensis/ultraestrutura , Manose/farmacologia , Microscopia Eletrônica de Varredura , Prodigiosina/isolamento & purificação , Serratia marcescens/química , Serratia marcescens/ultraestruturaRESUMO
Studies on the lysis of L. chagasi caused by the bacteria Serratia marcescens were carried out. In vitro experiments demonstrated that S. marcescens variant SM 365, a prodigiosin pigment producer, lysed this species of Leishmania but variant DB11, a nonpigmented bacteria, was unable to lyse the parasite. High concentrations of d-mannose were found to protect L. chagasi markedly diminishing the lysis by S. marcescens SM 365. Promastigotes of L. chagasi bound the lectin Concanavalin A conjugated with FITC, the fluorescence was intensely found at the base of the flagellum (flagellar pocket). Scanning electron microscopy revealed that the bacteria adherence occurred mainly in the flagellar pocket. S. marcescens SM 365 formed filamentous structures, identified as biofilms, which connect the protozoan to the developing bacterial clusters, in low concentrations of bacteria after 30 min incubation time. We suggest that bacterial mannose-sensitive (MS) fimbriae are relevant to S. marcescens SM 365 in the lysis of L. chagasi.
Assuntos
Leishmania infantum/microbiologia , Serratia marcescens/fisiologia , Animais , Aderência Bacteriana/fisiologia , Biofilmes , Concanavalina A/química , Relação Dose-Resposta a Droga , Fímbrias Bacterianas/fisiologia , Flagelos/microbiologia , Flagelos/ultraestrutura , Fluoresceína-5-Isotiocianato/análogos & derivados , Fluoresceína-5-Isotiocianato/química , Interações Hospedeiro-Patógeno , Cinética , Leishmania infantum/metabolismo , Leishmania infantum/ultraestrutura , Manose/metabolismo , Manose/farmacologia , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência , Microscopia de Interferência , Serratia marcescens/ultraestruturaRESUMO
Serratia marcescens strains are ubiquitous bacteria isolated from environmental niches, such as soil, water, and air, and also constitute emergent nosocomial opportunistic pathogens. Among the numerous extracellular factors that S. marcescens is able to produce, the PhlA phospholipase is the only described exoprotein secreted by the flagellar apparatus while simultaneously being a member of the flagellar regulon. To gain insight into the regulatory mechanism that couples PhlA and flagellar expression, we conducted a generalized insertional mutagenesis and screened for PhlA-deficient strains. We found that three independent mutations in the wec cluster, which impaired the assembly of enterobacterial common antigen (ECA), provoked the inhibition of PhlA expression. Swimming and swarming assays showed that in these strains, motility was severely affected. Microscopic examination and flagellin immunodetection demonstrated that a strong defect in flagellum expression was responsible for the reduced motility in the wec mutant strains. Furthermore, we determined that in the ECA-defective strains, the transcriptional cascade that controls flagellar assembly was turned off due to the down-regulation of flhDC expression. These findings provide a new perspective on the physiological role of the ECA, providing evidence that in S. marcescens, its biosynthesis conditions the expression of the flagellar regulon.
Assuntos
Antígenos de Bactérias/fisiologia , Flagelos/fisiologia , Serratia marcescens/fisiologia , Antígenos de Bactérias/genética , Sequência de Bases , Primers do DNA , Elementos de DNA Transponíveis , DNA Bacteriano/genética , Humanos , Dados de Sequência Molecular , Mutagênese , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Serratia marcescens/genética , Serratia marcescens/isolamento & purificação , Infecções Urinárias/microbiologiaRESUMO
A few days after blood meal the number of bacteria in the anterior midgut (stomach) of Rhodnius prolixus, a vector of Trypanosoma cruzi, the causative agent of Chagas' disease, increases dramatically. Many of the bloodstream trypomastigotes of the pathogenic protozoan as well as ingested erythrocytes are lysed in the stomach. Incubation of T. cruzi with Serratia marcescens variant SM365, lead to parasite lysis. In the present study, this bacterium rapidly adhered to the protozoan surface through d-mannose recognizing fimbriae and rapidly induced its complete lysis. In contrast, the DB11 variant of the same bacterial species did not adhere and did not induce protozoan lysis. Scanning and transmission electron microscopy revealed that following bacteria-protozoan attachment there is an assembly of long filamentous structures, identified as a biofilm, which connect the protozoan to the bacteria forming bacterial clusters. We conclude that parasite lysis and biofilm formation mechanisms are important for understanding parasite-microbiota interactions in the gut of insect vectors of trypanosomatids.