RESUMO
Serine protease inhibitor, represented by serpin, plays an important inhibitory role on proteases involved in the immune responses. To clarify the immune characterizations of serpin, a novel serpin (Lvserpin3) encoding for 410 amino acids with a 23-amino acid signal peptide and a serpin domain was identified from the Pacific white shrimp Litopenaeus vannamei. Lvserpin3 expressed strongest in hepatopancreas, and was significantly up-regulated in the early stage upon Vibrio anguillarum, Micrococcus lysodeikticus or White Spot Syndrome Virus (WSSV) infection. Suppression of Lvserpin3 by dsRNA led to a significant increase in the transcripts of LvPPAF, LvproPO and phenoloxidase (PO) activity, and also led to the high cumulative mortality. The recombinant Lvserpin3 protein (rLvserpin3) inhibited the proteases secreted by M. lysodeikticus and Bacillus subtilis, and further exhibited inhibitory role on the growth of B. subtilis and M. lysodeikticu. Moreover, rLvserpin3 was found to be able to block the activation of prophenoloxidase system. Taken together, the results imply that Lvserpin3 may be involved in shrimp innate immunity via the inhibition of bacterial proteases and proteases involved in prophenoloxidase system.
Assuntos
Proteínas de Artrópodes/imunologia , Proteínas de Bactérias/antagonistas & inibidores , Catecol Oxidase/antagonistas & inibidores , Precursores Enzimáticos/antagonistas & inibidores , Penaeidae/imunologia , Inibidores de Serina Proteinase/imunologia , Serpinas/imunologia , Animais , Proteínas de Artrópodes/genética , Proteínas de Bactérias/metabolismo , Catecol Oxidase/metabolismo , Infecções por Vírus de DNA/imunologia , Infecções por Vírus de DNA/veterinária , DNA Complementar/genética , Precursores Enzimáticos/metabolismo , Infecções por Bactérias Gram-Positivas/imunologia , Infecções por Bactérias Gram-Positivas/veterinária , Micrococcus/crescimento & desenvolvimento , Dados de Sequência Molecular , Penaeidae/microbiologia , Penaeidae/virologia , Peptídeo Hidrolases/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Análise de Sequência de DNA , Inibidores de Serina Proteinase/genética , Vibrio/crescimento & desenvolvimento , Vibrioses/imunologia , Vibrioses/veterinária , Vírus da Síndrome da Mancha Branca 1RESUMO
BACKGROUND: The camel is an excellent source of high quality meat and camel meat might be a potential alternative for beef. This study aimed to manipulate the raw camel meat for the production of stable and acceptable emulsion sausage, as well as to study the effect of cooking at different core temperatures on the tenderness, sensory quality and microstructure of produced sausage. RESULTS: Increasing the cooking temperature of sausages resulted in reduction of the shear force values from 2.67 kgf after cooking at 85 °C to 1.57 kgf after cooking at 105 °C. The sensory scores of sausages have been improved by increasing the cooking core temperature of meat batter. The light and scanning electron microscope micrographs revealed solubilisation of the high quantity of connective tissue of camel meat. High emulsion stability values for the camel meat batter associated with high values of water-holding capacity for raw camel meat and meat batter have been recorded. CONCLUSION: Stable and acceptable camel meat emulsion can be developed from camel meat. Increasing the cooking core temperature of meat batter improved the quality of produced sausages. Therefore, camel meat emulsion sausages might be a potential alternative for beef particularly in Asian and African countries. © 2015 Society of Chemical Industry.
Assuntos
Camelus , Culinária , Qualidade dos Alimentos , Produtos da Carne/análise , Carne/análise , Animais , Tecido Conjuntivo/química , Tecido Conjuntivo/ultraestrutura , Egito , Emulsões , Fermentação , Preferências Alimentares/etnologia , Armazenamento de Alimentos , Temperatura Alta/efeitos adversos , Humanos , Carne/microbiologia , Produtos da Carne/microbiologia , Fenômenos Mecânicos , Micrococcus/crescimento & desenvolvimento , Micrococcus/metabolismo , Microscopia Eletrônica de Varredura , Músculo Esquelético/química , Músculo Esquelético/ultraestrutura , Refrigeração , Sensação , Resistência ao Cisalhamento , Água/análiseRESUMO
The analysis was carried out to detect mycobiota of tunica mucosa of mouth and surface of dental prostheses under orthopedic rehabilitation using removable acrylic laminar dental prostheses. The inoculation of biosamples received from examined patients permitted to isolate Candida albicans. The C. albicans from tunica mucosa of mouth of patients before prosthetics inoculated in low concentration making up 0.33±0.23 CFU/ml in comparison with concentration of 1.92±0.53 CFU/ml after prosthetics. The highest content of C. albicans was marked in biosample from surface of dental prostheses in comparison with biotope of tunica mucosa of mouth of patients. The concentration of microbiota from surface of dental prostheses signicantly surpassed the same on tunica mucosa of mouth of patients prior prosthetics. In patients with removable acrylic laminar dental prostheses under orthopedic rehabilitation various spectrum of representatives of microbiota was detected From biosamples from surface of dentalprostheses of patients the most frequently were inoculated such representatives of gram-positive microbiota as S. aureus, Micrococcus spp., S.haemolyticus, and of gram-negative microbiota Klebsiella pneumonae, Pseudomonas aeruginosa. The cultural analysis of biosamples from patients with removable acrylic laminar dental prostheses detected Candida albicans on tunica mucosa of mouth before and after prosthetics as well as on surfaces of prostheses. The highest concentration of C.albicans is established in case of colonization of removable acrylic laminar dental prostheses. The received data testifies possible involvement of fungi capable of expressed potential ofpathogenicity, in development and maintenance of inflammatory process of tunica mucosa of mouth under orthopedic rehabilitation using removable acrylic laminar dental prostheses.
Assuntos
Acrilatos , Prótese Parcial Removível/microbiologia , Mucosa Bucal/microbiologia , Boca/microbiologia , Técnicas de Tipagem Bacteriana , Candida albicans/crescimento & desenvolvimento , Candida albicans/isolamento & purificação , Contagem de Colônia Microbiana , Humanos , Klebsiella pneumoniae/crescimento & desenvolvimento , Klebsiella pneumoniae/isolamento & purificação , Microbiota/fisiologia , Micrococcus/crescimento & desenvolvimento , Micrococcus/isolamento & purificação , Pseudomonas aeruginosa/crescimento & desenvolvimento , Pseudomonas aeruginosa/isolamento & purificação , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/isolamento & purificação , Staphylococcus haemolyticus/crescimento & desenvolvimento , Staphylococcus haemolyticus/isolamento & purificaçãoRESUMO
This study investigates the antibacterial effects of the ruthenium(II) complex RuBP and the mechanism of RuBP action on bacteria. Results show that RuBP can inhibit the growth of Gram-positive bacteria, such as Staphylococcus aureus and Micrococcus tetragenus. Cellular uptake and laser confocal microscopic studies reveal the efficient uptake of RuBP by M. tetragenus cells. Scanning electron microscopic observations of the morphologies of M. tetragenus and S. aureus treated with RuBP further confirm that direct contact of both bacteria with RuBP can damage the cell membrane and membrane integrity, which may eventually induce growth inhibition and bacterial death. After RuBP treatment, the electrical conductivity of the bacterial suspensions increases. Spectroscopic studies and agarose gel electrophoresis indicate that intact DNA and RNA decrease or disappear in RuBP-treated bacterial cells, thus demonstrating that RuBP performs its antibacterial function by increasing the permeability of cell membranes. This study provides new insights for understanding the antibacterial actions of RuBP and designing metal complex antibiotics for other biomedical applications.
Assuntos
Antibacterianos/farmacologia , Permeabilidade da Membrana Celular/efeitos dos fármacos , Piridinas/química , Compostos de Rutênio/farmacologia , Testes de Sensibilidade Microbiana , Micrococcus/efeitos dos fármacos , Micrococcus/crescimento & desenvolvimento , Microscopia Eletrônica de Varredura , Compostos de Rutênio/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimentoRESUMO
The spore-forming bacterium Bacillus licheniformis is a common contaminant of milk and milk products. Strains of this species isolated from dairy products can be differentiated into three major groups, namely, G, F1, and F2, using random amplification of polymorphic DNA (RAPD) analysis; however, little is known about the genomic differences between these groups and the identity of the fragments that make up their RAPD profiles. In this work we obtained high-quality draft genomes of representative strains from each of the three RAPD groups (designated strain G-1, strain F1-1, and strain F2-1) and compared them to each other and to B. licheniformis ATCC 14580 and Bacillus subtilis 168. Whole-genome comparison and multilocus sequence typing revealed that strain G-1 contains significant sequence variability and belongs to a lineage distinct from the group F strains. Strain G-1 was found to contain genes coding for a type I restriction modification system, urease production, and bacitracin synthesis, as well as the 8-kbp plasmid pFL7, and these genes were not present in strains F1-1 and F2-1. In agreement with this, all isolates of group G, but no group F isolates, were found to possess urease activity and antimicrobial activity against Micrococcus. Identification of RAPD band sequences revealed that differences in the RAPD profiles were due to differences in gene lengths, 3' ends of predicted primer binding sites, or gene presence or absence. This work provides a greater understanding of the phylogenetic and phenotypic differences observed within the B. licheniformis species.
Assuntos
Bacillus/genética , DNA Bacteriano/genética , Laticínios/microbiologia , Genoma Bacteriano , Antibiose , Bacillus/classificação , Bacillus/isolamento & purificação , Bacillus/fisiologia , DNA Bacteriano/química , Genótipo , Micrococcus/crescimento & desenvolvimento , Dados de Sequência Molecular , Técnica de Amplificação ao Acaso de DNA Polimórfico , Análise de Sequência de DNARESUMO
The unique high isoelectric point of lysozyme (LYZ) restricts its application in composite antibacterial coating due to the unfavorable liability to electrostatic interaction with other components. In this work, the antibacterial activity of a dispersible LYZ-carboxymethyl konjac glucomannan (CMKGM) polyelectrolyte complex was evaluated. Kinetic analysis revealed that, compared with free LYZ, the complexed enzyme exhibited decreased affinity (Km) but markedly increased Vmax against Micrococcus lysodeikticus, and QCM and dynamic light scattering analysis confirmed that the complex could bind with the substrate but in a much lower ratio. The complexation with CMKGM did not alter the antibacterial spectrum of LYZ, and the complex exerted antibacterial function by delaying the logarithmic growth phase and impairing the cell integrity of Staphylococcus aureus. Since the LYZ-CMKGM complex is dispersible in water and could be assembled easily, it has great potential as an edible coating in food preservation.
Assuntos
Antibacterianos , Mananas , Muramidase , Staphylococcus aureus , Mananas/química , Mananas/farmacologia , Mananas/metabolismo , Muramidase/química , Muramidase/metabolismo , Muramidase/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Cinética , Micrococcus/efeitos dos fármacos , Micrococcus/crescimento & desenvolvimentoRESUMO
Twenty strains of bacteria resistant to high concentrations of chromate were isolated from different ecological niches. They were able to reduce chromate to compounds of trivalent chromium--nonsoluble chromium hydroxide or soluble crystalline hydrates of trivalent chromium. The growth features of these microorganisms on media containing chromate at high concentrations (up to 20.0 g/l) are described. Besides chromate bacteria can reduce vanadate to compounds of V(4+) and Mo(6+) to Mo(5+). The best reduction takes place on the media where MPB. glucose or ethanol serves as the source of carbon. The growth and reduction of anion-in-study did not occur on organic acids. It was shown that tungstate, chlorate or perchlorate were not toxic for the studied bacteria up to concentrations of 10.0 g/l, however were not reduced by these microorganisms. The most active strains belong to genera Pseudomonas, Oerskovia, Bacillus, Micrococcus.
Assuntos
Bacillus/metabolismo , Cromatos/metabolismo , Poluentes Ambientais/metabolismo , Micrococcus/metabolismo , Pseudomonas/metabolismo , Vanadatos/metabolismo , Bacillus/crescimento & desenvolvimento , Biodegradação Ambiental , Cloratos/química , Meios de Cultura , Etanol/metabolismo , Glucose/metabolismo , Lagos , Micrococcus/crescimento & desenvolvimento , Oxirredução , Percloratos/química , Pseudomonas/crescimento & desenvolvimento , EsgotosRESUMO
Transgenesis has been used for expressing human lysozyme (hLZ) in the milk of livestock to improve their disease resistance. Here we describe a human lactoferrin (hLF) BAC as a candidate vector for high-level expression of hLZ in the milk of transgenic mice. Using recombineering, hLF genomic DNA in the hLF BAC was replaced by the hLZ gene (from the ATG start codon to the TAA stop codon), and flanking regions of the hLF gene (a 90-kb 5' and a 30-kb 3') were used as transcriptional control elements for hLZ expression. When this construct was used to generate transgenic mice, rhLZ was highly expressed in the milk of four transgenic mouse lines (1.20-1.76 g/L), was expressed at a lower level in one additional line (0.21 g/L). rhLZ from the milk of these transgenic mice exhibited the same antibacterial activity as native hLZ. Our results suggest a potential approach for producing large amounts of hLZ in the milk of livestock.
Assuntos
Regulação Enzimológica da Expressão Gênica , Camundongos Transgênicos , Leite/metabolismo , Muramidase/biossíntese , Proteínas Recombinantes/biossíntese , Animais , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Western Blotting , Cromossomos Artificiais Bacterianos/genética , Cromossomos Artificiais Bacterianos/metabolismo , Feminino , Engenharia Genética/métodos , Vetores Genéticos/genética , Vetores Genéticos/metabolismo , Genoma Humano , Humanos , Lactoferrina/genética , Lactoferrina/metabolismo , Masculino , Camundongos , Testes de Sensibilidade Microbiana , Micrococcus/efeitos dos fármacos , Micrococcus/crescimento & desenvolvimento , Muramidase/genética , Muramidase/farmacologia , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacologia , Transcrição GênicaRESUMO
Rapid cooling of shell eggs by using liquid CO(2) has shown increased bactericidal effects along with saturation of the egg albumen with CO(2). Lysozyme is a bactericidal enzyme present in chicken eggs, and it lyses gram-positive bacteria. Newly laid chicken eggs have an initial pH of 7.6 to 8.5 and are saturated with CO(2). During storage, the pH gradually increases to 9.7, accompanied by a loss of CO(2). It is hypothesized that the lysozyme activity is influenced by either CO(2) concentration or pH changes resulting from CO(2) loss. The objective of this study was to determine the lytic activity of purified lysozyme and chicken egg white (unpurified lysozyme) under varying conditions of temperature, pH, and CO(2) gas concentration. Lytic activity was determined by a standard microbial assay using lyophilized Micrococcus lysodeikticus. A 2 × 4 × 2 × 2 × 3 factorial design consisting of 2 temperatures (5 and 22°C), 4 pH (4.5, 6.5, 8.0, and 9.5), 2 treatments (with and without CO(2)), 2 types of lysozyme (purified and unpurified egg white), and 3 replicates was used. The highest lytic activity was found at pH 6.5 and 22°C. At pH 4.5 and 8.0, the addition of CO(2) increased lytic activity by more than 50% at both temperatures. At pH 6.5, lytic activity was maintained with CO(2) addition at both temperatures. At pH 9.5, lytic activity without CO(2) addition was high; however, adding CO(2) reduced lytic activity to zero. In conclusion, both pH and CO(2) treatment influence lysozyme activity.
Assuntos
Dióxido de Carbono/farmacologia , Clara de Ovo/química , Muramidase/metabolismo , Animais , Galinhas , Temperatura Baixa , Clara de Ovo/microbiologia , Concentração de Íons de Hidrogênio , Micrococcus/crescimento & desenvolvimentoRESUMO
AIMS: In the present study, chromogenic (red) bacteria were used to simulate actual target bacteria during set-up and optimization of an isolation process of bacteria, designed for food samples. Isolation of bacteria from food in the context of molecular biological detection of food pathogens is a multistep process. Development of such a separation method requires continuous monitoring of the location of the presumable targets in the sample tubes. Therefore, red-coloured pigmented bacteria were used as substitutes for the actual target bacteria, during the establishment of a new sample preparation technique. METHODS AND RESULTS: The chromogenic bacteria Micrococcus roseus and Serratia marcescens were confirmed to withstand the physical (e.g. centrifugal forces) and chemical (e.g. lysis buffer composition) conditions required during establishment of the new technique. Furthermore, the suitability of these model bacteria to substitute for the actual target pathogens (Salmonella enterica subsp. enterica serovar Typhimurium and Listeria monocytogenes) was assured by testing the physical properties of the model bacteria with respect to the proposed separation methods. CONCLUSION: Visibility of the pigmented bacteria within the complex sample matrices served to allocate bacterial content during the various steps necessary for finalization of the method protocol. The presumptive bacterial targets can be allocated simply by visualization of their bright red colour silhouetted against the background sample matrix. SIGNIFICANCE AND IMPACT OF STUDY: The use of pigmented bacteria as substitutes for actual colourless target bacteria during design and development of a bacterial isolation method is a simple and inexpensive application. It saves a huge amount of time and resources, as the proof of principle of new methods is possible in rapid succession.
Assuntos
Microbiologia de Alimentos , Doenças Transmitidas por Alimentos/microbiologia , Micrococcus/crescimento & desenvolvimento , Modelos Biológicos , Pigmentação , Serratia marcescens/crescimento & desenvolvimento , Doenças Transmitidas por Alimentos/prevenção & controle , Micrococcus/citologia , Kit de Reagentes para Diagnóstico , Serratia marcescens/citologiaRESUMO
Micrococcus luteus and Azotobacter sp. cells grown in broth in contact with a dialysis membrane containing lead bromide were found to immobilize 4.9 and 3.1 x 10(2) milligrams of lead per gram of whole cells, on a dry weight basis, respectively. Culture turbidity and cell count measurements on these and other cell cultures show that lead bromide, lead iodide, and lead bromochloride in concentrations approaching solubility limits have no detectable effect on overall growth rate and cell viability. Analyses of cellular subfractions reveal that fractions of cell wall plus membrane contain 99.3 and 99.1 percent of the lead found associated with Micrococcus luteus and Azotobacter sp., respectively. The remainder is found associated with the cytoplasmic fractions.
Assuntos
Azotobacter/metabolismo , Chumbo/metabolismo , Micrococcus/metabolismo , Azotobacter/citologia , Azotobacter/crescimento & desenvolvimento , Brometos/metabolismo , Fracionamento Celular , Membrana Celular/análise , Parede Celular/análise , Citoplasma/análise , Chumbo/análise , Chumbo/farmacologia , Micrococcus/citologia , Micrococcus/crescimento & desenvolvimentoRESUMO
In this study we tested the antimicrobial activity of polyethylene films modified by means of plasma processes that were followed by the chemical immobilization of lysozyme, an antimicrobial enzyme. To chemically immobilize the enzyme in its active form at the surface of polyethylene, substrates that had been plasma treated under different experimental conditions were soaked in lysozyme solutions at different concentrations. The immobilization of the enzyme was checked, and the antimicrobial activity of the films was investigated by observing the death rate of Micrococcus lysodeikticus cells suspended in phosphate buffer in contact with the films. The results clearly indicate that plasma-treated films loaded with lysozyme are active against the selected microorganism. A modified version of the Gompertz equation was used to quantitatively valuate the dependence of the antimicrobial activity of the films under both plasma treatment conditions and lysozyme concentrations.
Assuntos
Antibacterianos/farmacologia , Embalagem de Medicamentos/métodos , Embalagem de Alimentos/métodos , Micrococcus/fisiologia , Muramidase/farmacologia , Contagem de Colônia Microbiana , Qualidade de Produtos para o Consumidor , Relação Dose-Resposta a Droga , Enzimas Imobilizadas , Microbiologia de Alimentos , Conservação de Alimentos/métodos , Testes de Sensibilidade Microbiana , Micrococcus/efeitos dos fármacos , Micrococcus/crescimento & desenvolvimento , PolietilenoRESUMO
In this study, cloth disfeaturement was investigated biologically. To clarify whether or not microbes can cause cloth disfeaturement, and to identify the microbes causing the disfeaturement, worn cloth samples were incubated on sweat-ingredient agar medium. Non-sterilized cloth samples became yellow-colored during incubation, and bacterial strains belonging to the genera Bacillus, Brevibacterium, Kocuria, Micrococcus and Staphylococcus were isolated from the yellow-colored parts. Two major isolates close to the genera Bacillus and Micrococcus were inoculated separately or together on cloth samples to examine whether or not these isolates can cause colorization. When the isolate close to Micrococcus was inoculated on its own or mixed with the isolate close to Bacillus, the samples turned yellow to a greater extent and a biofilm-like structure was observed by SEM on the colored areas. In contrast, the isolate close to Bacillus alone barely caused any colorization, and no biofilm-like structure was observed. From the yellow-colored samples, bacterial strains with the same 16S rRNA gene sequences as those of the inoculated strains were re-isolated. These results strongly suggest that the bacterial strain belonging to genus Micrococcus causes cloth colorization by forming a biofilm structure.
Assuntos
Bacillus/isolamento & purificação , Biofilmes/crescimento & desenvolvimento , Brevibacterium/isolamento & purificação , Micrococcus/isolamento & purificação , Staphylococcus/isolamento & purificação , Têxteis/microbiologia , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Brevibacterium/crescimento & desenvolvimento , Brevibacterium/metabolismo , Humanos , Micrococcus/crescimento & desenvolvimento , Micrococcus/metabolismo , Microscopia Eletrônica , Staphylococcus/crescimento & desenvolvimento , Staphylococcus/metabolismo , Suor/metabolismoRESUMO
Cassava fish (Pseudotolithus sp.) was naturally fermented on three different occasions at room temperature (28-30 degrees C) for 3 to 8 days and the microbial population and the occurrence of various bacterial species were monitored. In general, after a slight increase during the early stages of fermentation, the microbial population decreased as the fermentation progressed. A total of 224 isolates belonging to the genera Bacillus, Staphylococcus, Micrococcus, Streptococcus, Corynebacterim, Pseudomonas, Achromobacter and Alcaligenes were isolated from the fermenting fish samples and the predominant ones were identified at the species level. Bacillus spp. and Staphylococcus spp. were the predominant genera and accounted for 48.7% and 27.3% of the total number of isolates respectively. Bacillus subtilis and Bacillus licheniformis, Staphylococcus lentus and Staphylococcus xylosus and Micrococcus luteus were the representative strains isolated during the fermentation. Bacillus spp., Staphylococcus spp. and Micrococcus spp. initiated the fermentation but Micrococcus spp. were few in numbers and died off after four (4) days of fermentation while Bacillus spp. and Staphylococcus spp. persisted up to the end of fermentation. Enterobacteriaceae were fewer in numbers at the start of fermentation (10(2) cfu/g) and their numbers decreased to less than 10 cfu/g after two days of fermentation. Bacillus spp. as well as Staphylococcus spp. isolated possessed moderate proteolytic and lipolytic activities. Micrococcus spp. showed weak proteolytic activity and no lipolytic activity.
Assuntos
Bacillus/isolamento & purificação , Fermentação , Produtos Pesqueiros/microbiologia , Microbiologia de Alimentos , Staphylococcus/isolamento & purificação , Animais , Bacillus/crescimento & desenvolvimento , Bacillus/metabolismo , Contagem de Colônia Microbiana , Humanos , Micrococcus/crescimento & desenvolvimento , Micrococcus/isolamento & purificação , Micrococcus/metabolismo , Staphylococcus/crescimento & desenvolvimento , Staphylococcus/metabolismo , Temperatura , Fatores de TempoRESUMO
Magnetic poly(2-hydroxyethyl methacrylate) mPHEMA beads carrying Cibacron Blue F3GA were prepared by suspension polymerization of HEMA in the presence of Fe3O4 nano-powder. Average size of spherical beads was 80-120 microm. The beads had a specific surface area of 56.0m(2)/g. The characteristic functional groups of dye-attached mPHEMA beads were analyzed by Fourier transform infrared spectrometer (FTIR) and Raman spectrometer. mPHEMA with a swelling ratio of 68% and carrying 28.5 micromol CibacronBlueF3GA/g were used for the purification of lysozyme. Adsorption studies were performed under different conditions in a magnetically stabilized fluidized bed (i.e., pH, protein concentration, flow-rate, temperature, and ionic strength). Lysozyme adsorption capacity of mPHEMA and mPHEMA/Cibacron Blue F3GA beads were 0.8 mg/g and 342 mg/g, respectively. It was observed that after 20 adsorption-desorption cycle, mPHEMA beads can be used without significant loss in lysozyme adsorption capacity. Purification of lysozyme from egg white was also investigated. Purification of lysozyme was monitored by determining the lysozyme activity using Micrococcus lysodeikticus as substrate. The purity of the desorbed lysozyme was about 87.4% with recovery about 79.6%. The specific activity of the desorbed lysozyme was high as 41.586 U/mg.
Assuntos
Muramidase/isolamento & purificação , Triazinas/química , Animais , Galinhas , Magnetismo , Micrococcus/crescimento & desenvolvimento , Muramidase/química , Muramidase/farmacologia , Poli-Hidroxietil Metacrilato/químicaRESUMO
We determined the toxicity of various chlorophenols, especially pentachlorophenol (PCP), on five bacterial strains and studied PCP biodegradation in soils amended with an organomineral complex (OMC) prepared from humic acids (organic part) bound on zeolite (inorganic part). Both components of OMC have excellent sorption properties and are of natural origin and therefore suitable to be used in the environment. Toxicity of chlorophenols depends not only on the number of chlorine atoms but also on their position on aromatic ring, and is thus regiospecific. Biodegradation of PCP was studied in three real completely characterized soil samples, Chernozem, Fluvisol, and Regosol, with and without the addition of OMC. The soils were sterilized and bioaugmented with the bacterial isolate Comamonas testosteroni CCM 7530. The immobilization effect of OMC in relation to PCP depends on the concentration of humic acids (HAs), the PCP concentration, and the content of organic carbon in soil. The microbial activity and the simulated action of acid rains led to the gradual release and biodegradation of the reversibly bound PCP without no initial toxic effect on indigenous or bioaugmented microorganisms. OMC appeared to be a good trap for PCP with potential applications in remediation technology because it reduces the potential toxicity of PCP to microbial community by lowering its bioavailability and thus facilitates its biodegradation.
Assuntos
Substâncias Húmicas , Pentaclorofenol/química , Poluentes do Solo/química , Zeolitas/química , Adsorção , Alcaligenes/efeitos dos fármacos , Alcaligenes/crescimento & desenvolvimento , Aliivibrio fischeri/efeitos dos fármacos , Aliivibrio fischeri/crescimento & desenvolvimento , Aliivibrio fischeri/metabolismo , Biodegradação Ambiental , Clorofenóis/toxicidade , Comamonas testosteroni/efeitos dos fármacos , Comamonas testosteroni/crescimento & desenvolvimento , Luminescência , Micrococcus/efeitos dos fármacos , Micrococcus/crescimento & desenvolvimento , Pentaclorofenol/metabolismo , Pentaclorofenol/toxicidade , Poluentes do Solo/metabolismo , Poluentes do Solo/toxicidadeRESUMO
This study was carried out to investigate the antimicrobial effects of chopped garlic in ground beef and raw meatball (çig köfte), which is a traditional food product eaten raw. Fresh minced ground beef and raw meatball batter prepared with traditional methods were separated into groups. Chopped and crushed garlic was added to each batch in order to reach various concentrations from 0% to 10%. The ground beef samples were stored at refrigerator and ambient temperatures. The raw meatball samples were only stored at room temperature. All samples were analyzed in order to determine the microbial counts at the 2(nd), 6(th), 12(th), and 24(th) hours of storage. Garlic addition decreased the microbial growth in some ground beef samples kept either at room temperature or in the refrigerator. However, microbial growth increased in some ground beef samples kept in similar conditions. The difference was found in samples kept in the refrigerator for 24 hours in terms of total aerobic mesophilic bacteria and coliform bacteria when garlic used at 10%. The effects of garlic on the microbial growth of both coliforms and Staphylococcus/Micrococcus in the samples kept at room temperature were increased. The yeast and mold counts in ground beef samples kept in any condition were not affected by garlic addition. However, the addition of garlic to the raw meatball mix decreased the microbial count, in terms of total aerobic mesophilic bacteria and yeast and mold counts, when the garlic was added at 5% or 10% (P < .05). The addition of 10% garlic to raw meatball caused a permanent decrease in yeast and mold count, unlike in ground beef. The results of this study indicate that the chopped garlic has a slowing-down effect on microbiological growth in ground meat depending on the garlic concentration, but this effect was not at an expected level even at the highest concentration, because potential antimicrobial agents in chopped garlic were probably insufficiently extracted.
Assuntos
Anti-Infecciosos , Alho/química , Carne/microbiologia , Raízes de Plantas/química , Animais , Bovinos , Contagem de Colônia Microbiana , Enterobacteriaceae/crescimento & desenvolvimento , Conservação de Alimentos , Carne/análise , Micrococcus/crescimento & desenvolvimento , Staphylococcus/crescimento & desenvolvimento , Leveduras/crescimento & desenvolvimentoRESUMO
Microorganisms play a significant role in bioremediation of heavy metal contaminated soil and wastewater. In this study, heavy metal resistant fungi and bacteria were isolated from the soil samples of an electroplating industry, and the bioaccumulations of Cr(VI) and Ni(II) by these isolates were characterized to evaluate their applicability for heavy metal removal from industrial wastewaters. The optimum pH and temperature conditions for both the growth and heavy metal removal were determined for each isolate. The optimal pH for fungal isolates was lower (5-5.2) than that for bacterial isolates (7). The observed effect(s) of pH was attributable mainly to organism-specific physiology because in all the tested cases the cellular growth positively correlated with heavy metal removal. Batch and tolerance experiments provided information for solid retention time (SRT) design and the lethal tolerance limits for the isolated microorganisms. Experimental results indicated that expanded SRTs (stationary phase) can be recommended while using the fungal and bacterial Cr-resistant isolates for removing chromium. In the case of Ni-resistant bacterial isolate, a non-expanded SRT was recommended for designing continuous-flow completely stirred (CFCS) bioreactor so that a mid-log phase of cellular growth can be kept during the bioaccumulation process. The tolerance data with a high range of heavy metal concentrations revealed the Cr-resistant isolates, especially the fungal one, could tolerate chromium toxicity at up to 10,000 mg L(-1) chromium. Result indicates the applicability of the isolated Micrococcus sp. and Aspergillus sp. for the removal of chromium and nickel from industrial wastewater.
Assuntos
Aspergillus/metabolismo , Cromo/metabolismo , Micrococcus/metabolismo , Níquel/metabolismo , Poluentes Químicos da Água/metabolismo , Adsorção , Aspergillus/efeitos dos fármacos , Aspergillus/crescimento & desenvolvimento , Proteínas de Bactérias/metabolismo , Biodegradação Ambiental , Cromo/toxicidade , Proteínas Fúngicas/metabolismo , Concentração de Íons de Hidrogênio , Resíduos Industriais , Micrococcus/efeitos dos fármacos , Micrococcus/crescimento & desenvolvimento , Níquel/toxicidade , Temperatura , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodosRESUMO
This study examined the performance of the chitosan-immobilized cadmium-resistant bacteria Arthrobacter sp. and Micrococcus sp. on cadmium phytoremediation by Chlorophytum laxum in cadmium-polluted soil. These immobilized cadmium-resistant bacteria can survive in cadmium-contaminated soil and significantly increased soil cadmium solubility, but the ability of chitosan-immobilized cells to increase cadmium solubility was lower than that of free cells. A pot experiment demonstrated that chitosan-immobilized Micrococcus sp. promoted the growth of C. laxum planted in cadmium-contaminated soil. A significant increase in the cadmium concentration in the roots and aboveground parts of C. laxum was found in plants inoculated with free and chitosan-immobilized cells of these bacteria. The performance of Arthrobacter sp. free cells to augment cadmium accumulation in C. laxum was a little bit better than that of chitosan-immobilized Arthrobacter sp., except at 9 weeks after planting. The phytoextraction coefficient, bioaccumulation factor, and translocation factor of C. laxum inoculated with free and chitosan-immobilized cells of cadmium-resistant bacteria were higher than those of the uninoculated control and increased with time. Our findings suggest that chitosan-immobilized cells can be exploited to enhance the efficiency of cadmium phytoremediation by C. laxum.
Assuntos
Arthrobacter/crescimento & desenvolvimento , Asparagaceae/crescimento & desenvolvimento , Cádmio/análise , Quitosana/química , Micrococcus/crescimento & desenvolvimento , Poluentes do Solo/análise , Arthrobacter/efeitos dos fármacos , Asparagaceae/efeitos dos fármacos , Biodegradação Ambiental , Cádmio/toxicidade , Micrococcus/efeitos dos fármacos , Modelos Teóricos , Raízes de Plantas/crescimento & desenvolvimento , Solo/química , Microbiologia do Solo , Poluentes do Solo/toxicidadeRESUMO
To enhance the production of micrococcin GO5, a bacteriocin produced by Micrococcus sp. GO5, cultivation conditions and medium composition were optimized. The optimal initial pH and temperature for bacteriocin production were 7.0-9.0 and 37 degrees C, respectively. Micrococcus sp. GO5 displayed the highest micrococcin GO5 activity when grown in modified MRS medium that contained lactose or sucrose, rather than glucose, as a carbon source. The maximum bacteriocin activity was obtained in modified MRS medium containing 0.5% tryptone and 1.0% yeast extract as nitrogen sources instead of the other nitrogen sources present in MRS medium. Bacteriocin production was greatly affected by the concentration of K(2)HPO(4); strain GO5 produced eight-fold more bacteriocin in medium containing 2.0-2.5% K(2)HPO(4) than in medium containing 0.2% K(2)HPO(4). The optimal concentration of MgSO(4).7H(2)O for bacteriocin production was 0.5%. The production of micrococcin GO5 was increased 32-fold in shake flask culture and 16-fold in a bioreactor using the optimized medium (TY medium), compared with culturing in MRS medium.