RESUMO
Microorganisms isolated from contaminated areas play an important role in bioremediation processes. They promote heavy metal removal from the environment by adsorbing ions onto the cell wall surface, accumulating them inside the cells, or reducing, complexing, or precipitating these substances in the environment. Microorganism-based bioremediation processes can be highly efficient, low-cost and have low environmental impact. Thus, the present study aimed to select Pb2+-resistant bacteria and evaluate the growth rate, biological activity, and the presence of genes associated with metal resistance. Serratia marcescens CCMA 1010, that was previously isolated from coffee processing wastewater, was selected since was able to growth in Pb2+ concentrations of up to 4.0 mM. The growth rate and generation time did not differ from those of the control (without Pb2+), although biological activity decreased in the first hour of exposure to these ions and stabilized after this period. The presence of the zntR, zntA and pbrA genes was analysed, and only zntR was detected. The zntR gene encodes a protein responsible for regulating the production of ZntA, a transmembrane protein that facilitates Pb2+ extrusion out of the cell. S. marcescens CCMA 1010 demonstrated a potential for use as bioindicator that has potential to be used in bioremediation processes due to its resistance to high concentrations of Pb2+, ability to grow until 24 h of exposure, and possession of a gene that indicates the existence of mechanisms associated with resistance to lead (Pb2+).
Assuntos
Metais Pesados , Purificação da Água , Cádmio/metabolismo , Serratia marcescens/genética , Serratia marcescens/metabolismo , Chumbo/metabolismo , Metais Pesados/metabolismo , Íons/metabolismo , Biodegradação AmbientalRESUMO
This work aimed to investigate the production of prodigiosin by S. marcescens UCP 1549 in solid-state fermentation (SSF), as a sustainable alternative for reducing the production costs and environmental impact. Thus, different agro-industrial substrates were used in the formulation of the prodigiosin production medium, obtaining the maximum yield of pigment (119.8 g/kg dry substrate) in medium consisting of 5 g wheat bran, 5% waste soybean oil and saline solution. The pigment was confirmed as prodigiosin by the maximum absorbance peak at 535 nm, Rf 0.9 in TLC, and the functional groups by infrared spectrum (FTIR). Prodigiosin demonstrated stability at different values of temperature, pH and NaCl concentrations and antimicrobial properties, as well as not show any toxicity. These results confirm the applicability of SSF as a sustainable and promising technology and wheat bran as potential agrosubstrate to produce prodigiosin, making the bioprocess economic and competitive for industrial purposes.
Assuntos
Microbiologia Industrial , Prodigiosina , Serratia marcescens , Antibacterianos/biossíntese , Meios de Cultura/química , Fermentação , Microbiologia Industrial/métodos , Prodigiosina/biossíntese , Serratia marcescens/metabolismoRESUMO
Serratia marcescens is an enteric bacterium that can function as an opportunistic pathogen with increasing incidence in clinical settings. This is mainly due to the ability to express a wide range of virulence factors and the acquisition of antibiotic resistance mechanisms. For these reasons, S. marcescens has been declared by the World Health Organization (WHO) as a research priority to develop alternative antimicrobial strategies. In this study, we found a PhoP-binding motif in the promoter region of transcriptional regulator RamA of S. marcescens RM66262. We demonstrated that the expression of ramA is autoregulated and that ramA is also part of the PhoP/PhoQ regulon. We have also shown that PhoP binds directly and specifically to ramA, mgtE1, mgtE2, lpxO1, and lpxO2 promoter regions and that RamA binds to ramA and lpxO1 but not to mgtE1 and lpxO2, suggesting an indirect control for the latter genes. Finally, we have demonstrated that in S. marcescens, RamA overexpression induces the AcrAB-TolC efflux pump, required to reduce the susceptibility of the bacteria to tetracycline and nalidixic acid. In sum, we here provide the first report describing the regulation of ramA under the control of the PhoP/PhoQ regulon and the regulatory role of RamA in S. marcescens. IMPORTANCE We demonstrate that in S. marcescens, the transcriptional regulator RamA is autoregulated and also controlled by the PhoP/PhoQ signal transduction system. We show that PhoP is able to directly and specifically bind to ramA, mgtE1, mgtE2, lpxO1, and lpxO2 promoter regions. In addition, RamA is able to directly interact with the promoter regions of ramA and lpxO1 but indirectly regulates mgtE1 and lpxO2. Finally, we found that in S. marcescens, RamA overexpression induces the AcrAB-TolC efflux pump, required to reduce susceptibility to tetracycline and nalidixic acid. Collectively, these results further our understanding of the PhoP/PhoQ regulon in S. marcescens and demonstrate the involvement of RamA in the protection against antibiotic challenges.
Assuntos
Proteínas de Bactérias/metabolismo , Resistência Microbiana a Medicamentos/genética , Serratia marcescens/genética , Serratia marcescens/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Gênica , Antibacterianos , Proteínas de Bactérias/genética , Cloranfenicol , Microbioma Gastrointestinal , Regulação Bacteriana da Expressão Gênica , Homeostase , Lipídeo A , Ácido Nalidíxico , Fenótipo , Regulon , Transdução de Sinais , Tetraciclina , Fatores de VirulênciaRESUMO
A novel pigmented bacterium, initially identified as 11E, was isolated from a site historically known to have various iron-related ores. Phylogenetic analysis of this bacterial strain showed that it belongs to Serratia marcescens. This pigmented S. marcescens 11E cultured individually with glucose, acetate, and glycerol as electron donors along with the soluble electron acceptor iron (Fe) (III) citrate offered a large reduction extent (45.3 %, 31.4 %, and 13.5 %, respectively). On the other hand, when iron oxide (Fe2O3) is used as electron acceptor, the pigmented strain produced a null reduction extent. Surprisingly, the absence of prodigiosin on the bacterial surface (non-pigmented strain) resulted in a large reduction extent of the non-soluble iron form (20-49%). All these extents were comparable and, in some cases, superior to those presented in the literature. Additionally, in the present study, it was found that anthraquinone sulfonate (AQS) stimulated Fe(III) reduction of soluble and non-soluble Fe species only with pigmented S. marcescens. In contrast, in the culture media with the non-pigmented strain, the presence of AQS did not stimulate the Fe(III) reduction. These results suggest that the pigmented phenotype of S. marcescens 11E may perform non-soluble Fe(III) reduction by electron shuttling. In contrast, for the non-pigmented phenotype of this bacterium, non-soluble Fe(III) reduction seems to proceed by direct contact. Our study demonstrates that this bacterium may be used in bioreduction process of heavy metals or as a biocatalyst in bioelectrochemical devices.
Assuntos
Compostos Férricos/metabolismo , Prodigiosina/metabolismo , Serratia marcescens , Enzimas , Filogenia , RNA Ribossômico 16S/genética , Serratia marcescens/genética , Serratia marcescens/isolamento & purificação , Serratia marcescens/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
Background: Prodigiosin has been demonstrated to be an important candidate in investigating anticancer drugs and in many other applications in recent years. However, industrial production of prodigiosin has not been achieved. In this study, we found a prodigiosin-producing strain, Serratia marcescens FZSF02, and its fermentation strategies were studied to achieve the maximum yield of prodigiosin. Results: When the culture medium consisted of 16.97 g/L of peanut powder, 16.02 g/L of beef extract, and 11.29 mL/L of olive oil, prodigiosin reached a yield of 13.622 ± 236 mg/L after culturing at 26 °C for 72 h. Furthermore, when 10 mL/L olive oil was added to the fermentation broth at the 24th hour of fermentation, the maximum prodigiosin production of 15,420.9 mg/L was obtained, which was 9.3-fold higher than the initial level before medium optimization. More than 60% of the prodigiosin produced with this optimized fermentation strategy was in the form of pigment pellets. To the best of our knowledge, this is the first report on this phenomenon of pigment pellet formation, which made it much easier to extract prodigiosin at low cost. Prodigiosin was then purified and identified by absorption spectroscopy, HPLC, and LCMS. Purified prodigiosin obtained in this study showed anticancer activity in separate experiments on several human cell cultures: A549, K562, HL60, HepG2, and HCT116. Conclusions: This is a promising strain for producing prodigiosin. The prodigiosin has potential in anticancer medicine studies.
Assuntos
Prodigiosina/biossíntese , Prodigiosina/farmacologia , Serratia marcescens/metabolismo , Antineoplásicos/farmacologia , Arachis/química , Pós , Prodigiosina/isolamento & purificação , Espectrometria de Massas , Células Tumorais Cultivadas/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Cromatografia Líquida , Técnicas de Cultura de Células , Fermentação , Azeite de Oliva/química , Acetatos , NitrogênioRESUMO
Serratia marcescens is an opportunistic pathogen with increasing incidence in clinical settings. This is mainly attributed to the timely expression of a wide diversity of virulence factors and intrinsic and acquired resistance to antibiotics, including ß-lactams, aminoglycosides, quinolones, and polypeptides. For these reasons, S. marcescens has been recently categorised by the World Health Organization as one priority to strengthen efforts directed to develop new antibacterial agents. Therefore, it becomes critical to understand the underlying mechanisms that allow Serratia to succeed within the host. S. marcescens ShlA pore-forming toxin mediates phenotypes that alter homeostatic and signal transduction pathways of host cells. It has been previously demonstrated that ShlA provokes cytotoxicity, haemolysis and autophagy and also directs Serratia egress and dissemination from invaded nonphagocytic cells. However, molecular details of ShlA mechanism of action are still not fully elucidated. In this work, we demonstrate that Ni2+ selectively and reversibly blocks ShlA action, turning wild-type S. marcescens into a shlA mutant strain phenocopy. Combined use of Ni2+ and calcium chelators allow to discern ShlA-triggered phenotypes that require intracellular calcium mobilisation and reveal ShlA function as a calcium channel, providing new insights into ShlA mode of action on target cells.
Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Canais de Cálcio/metabolismo , Proteínas Hemolisinas/antagonistas & inibidores , Níquel/farmacologia , Serratia marcescens/efeitos dos fármacos , Fatores de Virulência/metabolismo , Animais , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/toxicidade , Toxinas Bacterianas/metabolismo , Células CHO , Cálcio/metabolismo , Cricetulus , Eritrócitos/microbiologia , Proteínas Hemolisinas/metabolismo , Proteínas Hemolisinas/toxicidade , Hemólise/efeitos dos fármacos , Interações Hospedeiro-Patógeno/efeitos dos fármacos , Humanos , Fenótipo , Serratia marcescens/metabolismo , Serratia marcescens/patogenicidadeRESUMO
BACKGROUND: Biosurfactants are surface-active agents produced by microorganisms that have higher efficiency and stability, lower toxicity and higher biocompatibility and biodegradability than chemical surfactants. Despite its properties and potential application in a wide range of environmental and industrial processes, biosurfactants are still not cost-competitive when compared to their synthetic counterparts. Cost effective technologies and renewable raw substrates as agro-industrial and regional waste from northeast of Brazil as cassava flour wastewater, supplemented with lactose and corn oil are mainly the chemically media for growing microorganism and in turn the production of the biosurfactant of quality. This study aimed to obtained biosurfactant by Serratia marcescens UCP 1549 containing cassava flour wastewater (CWW), by application of a full-factorial design, as sustainable practices in puts the production process in promising formulation medium. The characterization of the biomolecule was carried out, as well as the determination of its stability and toxicity for cabbage seeds. In addition, its ability to stimulate seed germination for agriculture application and oil spill bioremediation were investigated. RESULTS: Serratia marcescens showed higher reduction of surface tension (25.92 mN/m) in the new medium containing 0.2% lactose, 6% cassava flour wastewater and 5% corn waste oil, after 72 h of fermentation at 28 °C and 150 rpm. The substrate cassava flour wastewater showed a promising source of nutrients for biosurfactant production. The isolate biosurfactant exhibited a CMC of 1.5% (w/v) and showed an anionic and polymeric structure, confirmed by infrared spectra. The biomolecule demonstrated high stability under different temperatures, salinity and pH values and non-toxicity against to cabbage seeds. Thus, exploring biosurfactant their potential role in seeds germinations and the promotion and agricultural applications was investigated. In addition, the effectiveness of biosurfactant for removal burned motor oil adsorbed in sand was verified. CONCLUSIONS: The use of medium containing CWW not only reduces the cost of process of biosurfactant production, but also the environmental pollution due to the inappropriate disposal of this residue. This fact, added to the high stability and non-toxicity of the biosurfactant produced by S. marcescens UCP 1549, confirms its high environmental compatibility, make it a sustainable biocompound that can be replace chemical surfactants in diverse industries. In addition, the effectiveness of biosurfactant for stimulate seed germination and removing burned motor oil from sand, suggests its suitability for agriculture and bioremediation applications.
Assuntos
Biodegradação Ambiental , Serratia marcescens/metabolismo , Tensoativos/metabolismo , Reatores Biológicos , Brassica/efeitos dos fármacos , Brassica/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Serratia marcescens/química , Serratia marcescens/crescimento & desenvolvimento , Cloreto de Sódio/química , Poluentes do Solo/química , Poluentes do Solo/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier , Tensão Superficial , Tensoativos/química , Tensoativos/toxicidade , TemperaturaRESUMO
BACKGROUND: Proteomics is an important tool for the investigation of dynamic physiological responses of microbes under heavy metal stress. To gain insight into how bacteria respond to manganese (II) and identify the proteins involved in Mn (II) oxidation, the shotgun proteomics approach was applied to a potential Mn (II)-oxidizing Serratia marcescens strain cultivated in the absence and presence of Mn (II). RESULTS: The LG1 strain, which grew equally well in the two conditions, was found to express a set of proteins related to cellular processes vital for survival, as well as proteins involved in adaptation and tolerance to Mn (II). The multicopper oxidase CueO was identified, indicating its probable participation in the Mn (II) bio-oxidation; however, its expression was not modulated by the presence of Mn (II). A set of proteins related to cell and metabolic processes vital to the cells were downregulated in the presence of Mn (II), while cell membrane-related proteins involved in the maintenance of cell integrity and survival under stress were upregulated under this condition. CONCLUSIONS: These findings indicate that the LG1 strain may be applied successfully in the bioremediation of Mn (II), and the shotgun approach provides an efficient means for obtaining the total proteome of this species.
Assuntos
Proteínas de Bactérias/metabolismo , Manganês/metabolismo , Serratia marcescens/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteoma/química , Proteoma/genética , Proteoma/metabolismo , Proteômica , Serratia marcescens/química , Serratia marcescens/genética , Serratia marcescens/crescimento & desenvolvimentoRESUMO
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
Ants use pheromones to coordinate their communal activity. Volatile pyrazines, for instance, mediate food resource gathering and alarm behaviors in different ant species. Here we report that leaf-cutter ant-associated bacteria produce a family of pyrazines that includes members previously identified as ant trail and alarm pheromones. We found that L-threonine induces the bacterial production of the trail pheromone pyrazines, which are common for the host leaf-cutter ants. Isotope feeding experiments revealed that L-threonine along with sodium acetate were the biosynthetic precursors of these natural products and a biosynthetic pathway was proposed.
Assuntos
Formigas/metabolismo , Feromônios/metabolismo , Pirazinas/metabolismo , Serratia marcescens/metabolismo , Animais , Ecossistema , Cromatografia Gasosa-Espectrometria de Massas/métodos , Feromônios/química , Pirazinas/química , Acetato de Sódio/química , Acetato de Sódio/metabolismo , Treonina/química , Treonina/metabolismoRESUMO
The ability to detect and measure danger from an environmental signal is paramount for bacteria to respond accordingly, deploying strategies that halt or counteract potential cellular injury and maximize survival chances. Type VI secretion systems (T6SSs) are complex bacterial contractile nanomachines able to target toxic effectors into neighboring bacteria competing for the same colonization niche. Previous studies support the concept that either T6SSs are constitutively active or they fire effectors in response to various stimuli, such as high bacterial density, cell-cell contact, nutrient depletion, or components from dead sibling cells. For Serratia marcescens, it has been proposed that its T6SS is stochastically expressed, with no distinction between harmless or aggressive competitors. In contrast, we demonstrate that the Rcs regulatory system is responsible for finely tuning Serratia T6SS expression levels, behaving as a transcriptional rheostat. When confronted with harmless bacteria, basal T6SS expression levels suffice for Serratia to eliminate the competitor. A moderate T6SS upregulation is triggered when, according to the aggressor-prey ratio, an unbalanced interplay between homologous and heterologous effectors and immunity proteins takes place. Higher T6SS expression levels are achieved when Serratia is challenged by a contender like Acinetobacter, which indiscriminately fires heterologous effectors able to exert lethal cellular harm, threatening the survival of the Serratia population. We also demonstrate that Serratia's RcsB-dependent T6SS regulatory mechanism responds not to general stress signals but to the action of specific effectors from competitors, displaying an exquisite strategy to weigh risks and keep the balance between energy expenditure and fitness costs.IMPORTANCESerratia marcescens is among the health-threatening pathogens categorized by the WHO as research priorities to develop alternative antimicrobial strategies, and it was also recently identified as one major component of the gut microbiome in familial Crohn disease dysbiosis. Type VI secretion systems (T6SSs) stand among the array of survival strategies that Serratia displays. They are contractile multiprotein complexes able to deliver toxic effectors directed to kill bacterial species sharing the same niche and, thus, competing for vital resources. Here, we show that Serratia is able to detect and measure the extent of damage generated through T6SS-delivered toxins from neighboring bacteria and responds by transcriptionally adjusting the expression level of its own T6SS machinery to counterattack the rival. This strategy allows Serratia to finely tune the production of costly T6SS devices to maximize the chances of successfully fighting against enemies and minimize energy investment. The knowledge of this novel mechanism provides insight to better understand bacterial interactions and design alternative treatments for polymicrobial infections.
Assuntos
Antibiose , Proteínas de Bactérias/genética , Sistemas de Secreção Tipo VI/genética , Sistemas de Secreção Tipo VI/metabolismo , Acinetobacter/genética , Acinetobacter/metabolismo , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Serratia marcescens/genética , Serratia marcescens/metabolismoRESUMO
The intrinsic polymyxin resistance displayed by Serratia marcescens makes the acquisition of carbapenemase encoding genes a worrisome event. This study report a SME-4-producing S. marcescens isolate causing septic shock in Brazil. The insertion of novel resistance determinants and their consequent spread in our territory is noteworthy.
Assuntos
Proteínas de Bactérias/metabolismo , Infecções por Serratia/microbiologia , Serratia marcescens/isolamento & purificação , Antibacterianos/uso terapêutico , Brasil , Farmacorresistência Bacteriana/efeitos dos fármacos , Feminino , Humanos , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Infecções por Serratia/tratamento farmacológico , Serratia marcescens/metabolismo , beta-Lactamases/metabolismoRESUMO
This work addresses the production of prodigiosin from ram horn peptone (RHP) using MO-1, a local isolate in submerged culture. First, a novel gram-negative and rod-shaped bacterial strain, MO-1, was isolated from the body of the grasshopper (Poecilemon tauricola Ramme 1951), which was collected from pesticide-contaminated fields. Sequence analysis of 16S rDNA classified the microbe as Serratia marcescens. The substrate utilization potential (BIOLOG) and fatty acid methyl ester profile (FAME) of S. marcescens were also determined. The effect of RHP on the production of prodigiosin by S. marcescens MO-1 was investigated, and the results showed that RHP supplementation promoted the growth of MO-1 and increased the production of prodigiosin. A concentration of 0.4% (w/v) RHP resulted in the greatest yield of prodigiosin (277.74 mg/L) after 48 h when mannitol was used as the sole source of carbon. The pigment yield was also influenced by the types of carbon sources and peptones. As a result, RHP was demonstrated to be a suitable substrate for prodigiosin production. These results revealed that prodigiosin could be produced efficiently by S. marcescens using RHP.
Assuntos
Meios de Cultura/química , Peptonas/metabolismo , Prodigiosina/metabolismo , Serratia marcescens/crescimento & desenvolvimento , Serratia marcescens/metabolismo , Animais , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , Citosol/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácidos Graxos/análise , Gafanhotos/microbiologia , Dados de Sequência Molecular , Filogenia , Pigmentos Biológicos/metabolismo , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Serratia marcescens/classificação , Serratia marcescens/isolamento & purificaçãoRESUMO
This work addresses the production of prodigiosin from ram horn peptone (RHP) using MO-1, a local isolate in submerged culture. First, a novel gram-negative and rod-shaped bacterial strain, MO-1, was isolated from the body of the grasshopper (Poecilemon tauricola Ramme 1951), which was collected from pesticide-contaminated fields. Sequence analysis of 16S rDNA classified the microbe as Serratia marcescens. The substrate utilization potential (BIOLOG) and fatty acid methyl ester profile (FAME) of S. marcescens were also determined. The effect of RHP on the production of prodigiosin by S. marcescens MO-1 was investigated, and the results showed that RHP supplementation promoted the growth of MO-1 and increased the production of prodigiosin. A concentration of 0.4% (w/v) RHP resulted in the greatest yield of prodigiosin (277.74 mg/L) after 48 h when mannitol was used as the sole source of carbon. The pigment yield was also influenced by the types of carbon sources and peptones. As a result, RHP was demonstrated to be a suitable substrate for prodigiosin production. These results revealed that prodigiosin could be produced efficiently by S. marcescens using RHP.
Assuntos
Animais , Meios de Cultura/química , Peptonas/metabolismo , Prodigiosina/metabolismo , Serratia marcescens/crescimento & desenvolvimento , Serratia marcescens/metabolismo , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , Citosol/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácidos Graxos/análise , Gafanhotos/microbiologia , Dados de Sequência Molecular , Filogenia , Pigmentos Biológicos/metabolismo , /genética , Análise de Sequência de DNA , Serratia marcescens/classificação , Serratia marcescens/isolamento & purificaçãoRESUMO
This work addresses the production of prodigiosin from ram horn peptone (RHP) using MO-1, a local isolate in submerged culture. First, a novel gram-negative and rod-shaped bacterial strain, MO-1, was isolated from the body of the grasshopper (Poecilemon tauricola Ramme 1951), which was collected from pesticide-contaminated fields. Sequence analysis of 16S rDNA classified the microbe as Serratia marcescens. The substrate utilization potential (BIOLOG) and fatty acid methyl ester profile (FAME) of S. marcescens were also determined. The effect of RHP on the production of prodigiosin by S. marcescens MO-1 was investigated, and the results showed that RHP supplementation promoted the growth of MO-1 and increased the production of prodigiosin. A concentration of 0.4% (w/v) RHP resulted in the greatest yield of prodigiosin (277.74 mg/L) after 48 h when mannitol was used as the sole source of carbon. The pigment yield was also influenced by the types of carbon sources and peptones. As a result, RHP was demonstrated to be a suitable substrate for prodigiosin production. These results revealed that prodigiosin could be produced efficiently by S. marcescens using RHP.(AU)
Assuntos
Animais , Meios de Cultura/química , Peptonas/metabolismo , Prodigiosina/metabolismo , Serratia marcescens/crescimento & desenvolvimento , Serratia marcescens/metabolismo , Técnicas de Tipagem Bacteriana , Análise por Conglomerados , Citosol/química , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácidos Graxos/análise , Gafanhotos/microbiologia , Dados de Sequência Molecular , Filogenia , Pigmentos Biológicos/metabolismo , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Serratia marcescens/classificação , Serratia marcescens/isolamento & purificaçãoRESUMO
BACKGROUND: The adapted arcometer has been validated for use in adults. However, its suitability for use in children can be questioned given the structural differences present in these populations. OBJECTIVE: To verify the concurrent validity, repeatability, and intra- and inter-reproducibility of the adapted arcometer for the measurement of the angles of thoracic kyphosis and lumbar lordosis in children. METHOD: Forty children were evaluated using both sagittal radiography of the spine and the adapted arcometer. The evaluations using the arcometer were carried out by two trained evaluators on two different days. In the statistical treatment, the intraclass correlation coefficient (ICC), Pearson's product moment correlation, Spearman's rho, the paired t test, and Wilcoxon's test were used (α=.05). RESULTS: A moderate and significant correlation was found between the x-ray and the adapted arcometer regarding thoracic kyphosis, but no correlation was found regarding lumbar lordosis. Repeatability and intra-evaluator reproducibility of the thoracic kyphosis and lumbar lordosis were confirmed, which was not the case of inter-evaluator reproducibility. CONCLUSION: The adapted arcometer can be used to accompany postural alterations in children made by the same evaluator, while its use for diagnostic purposes and continued evaluation by different evaluators cannot be recommended. Further studies with the aim of adapting this instrument for use in children are recommended. .
Assuntos
Proteínas de Bactérias/análise , Glicoproteínas de Membrana/análise , Glicoproteínas de Membrana/genética , Prodigiosina/biossíntese , Serratia marcescens/metabolismo , Centrifugação com Gradiente de Concentração , Eletroforese em Gel de Poliacrilamida , Peso Molecular , Glicoproteínas de Membrana/biossíntese , Solubilidade , Sarcosina/análogos & derivados , Serratia marcescens/análiseRESUMO
Serratia marcescens is a Gram-negative bacterium that thrives in a wide variety of ambient niches and interacts with an ample range of hosts. As an opportunistic human pathogen, it has increased its clinical incidence in recent years, being responsible for life-threatening nosocomial infections. S. marcescens produces numerous exoproteins with toxic effects, including the ShlA pore-forming toxin, which has been catalogued as its most potent cytotoxin. However, the regulatory mechanisms that govern ShlA expression, as well as its action toward the host, have remained unclear. We have shown that S. marcescens elicits an autophagic response in host nonphagocytic cells. In this work, we determine that the expression of ShlA is responsible for the autophagic response that is promoted prior to bacterial internalization in epithelial cells. We show that a strain unable to express ShlA is no longer able to induce this autophagic mechanism, while heterologous expression of ShlA/ShlB suffices to confer on noninvasive Escherichia coli the capacity to trigger autophagy. We also demonstrate that shlBA harbors a binding motif for the RcsB regulator in its promoter region. RcsB-dependent control of shlBA constitutes a feed-forward regulatory mechanism that allows interplay with flagellar-biogenesis regulation. At the top of the circuit, activated RcsB downregulates expression of flagella by binding to the flhDC promoter region, preventing FliA-activated transcription of shlBA. Simultaneously, RcsB interaction within the shlBA promoter represses ShlA expression. This circuit offers multiple access points to fine-tune ShlA production. These findings also strengthen the case for an RcsB role in orchestrating the expression of Serratia virulence factors.
Assuntos
Autofagia/genética , Proteínas de Bactérias/genética , Toxinas Bacterianas/genética , Proteínas Hemolisinas/genética , Serratia marcescens/genética , Transcrição Gênica/genética , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Células Epiteliais/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Flagelos/genética , Flagelos/metabolismo , Proteínas Hemolisinas/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/genética , Serratia marcescens/metabolismoRESUMO
With the goal of understanding the chitinolytic mechanism of the potential biological control strain Serratia marcescens CFFSUR-B2, genes encoding chitinases ChiA, ChiB and ChiC, chitobiase (Chb) and chitin binding protein (CBP) were cloned, the protein products overexpressed in Escherichia coli as 6His-Sumo fusion proteins and purified by affinity chromatography. Following affinity tag removal, the chitinolytic activity of the recombinant proteins was evaluated individually and in combination using colloidal chitin as substrate. ChiB and ChiC were highly active while ChiA was inactive. Reactions containing both ChiB and ChiC showed significantly increased N-acetylglucosamine trimer and dimer formation, but decreased monomer formation, compared to reactions with either enzyme alone. This suggests that while both ChiB and ChiC have a general affinity for the same substrate, they attack different sites and together degrade chitin more efficiently than either enzyme separately. Chb and CBP in combination with ChiB and ChiC (individually or together) increased their chitinase activity. We report for the first time the potentiating effect of Chb on the activity of the chitinases and the synergistic activity of a mixture of all five proteins (the three chitinases, Chb and CBP). These results contribute to our understanding of the mechanism of action of the chitinases produced by strain CFFSUR-B2 and provide a molecular basis for its high potential as a biocontrol agent against fungal pathogens.
Assuntos
Acetilglucosaminidase/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/metabolismo , Quitina/metabolismo , Quitinases/metabolismo , Serratia marcescens/enzimologia , Acetilglucosaminidase/genética , Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Quitinases/genética , Cromatografia de Afinidade , Clonagem Molecular , Escherichia coli/genética , Expressão Gênica , Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Serratia marcescens/genética , Serratia marcescens/metabolismoRESUMO
Background: Light can be absorbed by bacterial pigment and affects its growth. Prodigiosin is a red pigment found in various bacterial species. The purpose of this study was to investigate the impacts of light on prodigiosin production, biomass formation, and membrane integrity of Serratia marcescens y2. Results: S. marcescens y2 grew better and produced more intracellular prodigiosin in darkness than in illumination. The pigment leakage ratio from cells was detected more in light than in darkness conditions. Ethidium bromide uptake assay could visually prove the prodigiosin-related loss of membrane integrity under illumination. A higher concentration of malondialdehyde (MDA) was detected in light-treated culture than in darkness. Tests of different light treatments (red, yellow, blue and green) showed that the maximum extracellular pigment and the minimum biomass formation and intracellular pigment were obtained in green light. Conclusions: Prodigiosin could absorb light, and then initiate phototoxicity damage of the cytomembrane.