Bacterial xanthan and ramnolipid simultaneous production using industrial oil produced water.

The present work aimed to give an economical destiny to the produced water, a residue generated by the oil and gas industry by means of producing bioactives such as xanthan gum and ramnolipid. These compounds are often used in combination during enhanced oil recovery strategies. On the other hand, reports on co-culture of bacterial strains that are responsible for their production are rare. This research shows a factorial design method associated with surface response analysis to optimize carbon sources, sucrose and crude glycerin, and fermentation agents for culturing Xanthomonas campestris and Pseudomonas aeruginosa using the described conditions. After the critical point validation resulting in xanthan and ramnolipid production of 8.69 and 4.80 g L-1, quality tests showed an apparent viscosity of 1006 cP with an emulsifying activity abouve 50% for 94 h.

Screening and testing potential inhibitors of sulphide gas production by sulphate-reducing bacteria.

Sulphate-reducing bacteria are commonly associated with biological causes of oil well souring. Biosulphetogenesis can directly affect oil quality and storage due to the accumulation of sulphides. In addition, these microorganisms can create bio-incrustation that can clog pipes. Sulphite reductase (SIR) is the enzyme responsible for converting ion sulphite into sulphide and several substances may interfere or control such activity. This interference can hinder growth of the sulphate-reducing bacteria and, consequently, it reduces sulphide accumulation in situ. This work focuses on molecular modelling techniques along with in vitro experiments in order to investigate the potential of two essential oils and one vegetable oil as main inhibitors of sulphite reductase activity. Docking simulation identified several substances present in Rosmarinus officinalis, Tea tree and Neem extractable oils as potential inhibitors of SIR. Substances present in Neem vegetable oil are the most potent inhibitors, followed by Rosmarinus officinalis and Tea tree essential oils. The Neem oil mixture showed a superior effectiveness in intracellular SIR inhibitory effects.

aPDT using nanoconcentration of 1,9-dimethylmethylene blue associated to red light is efficacious in killing Enterococcus faecalis ATCC 29212 in vitro.

The Enterococcus faecalis is a microorganism that causes multiple forms of resistance to a wide range of drugs used clinically. aPDT is a technique in which a visible light activates photosensitizer (PS), resulting in generation of reactive oxygen species that kill bacteria unselectively via an oxidative burst. aPDT is an alternative to antibiotics with the advantage of not causing resistance. The search for an alternative treatment of infections caused by E. faecalis, without using antibiotics, is off great clinical importance. The aim of present investigation was to assess the efficacy of using 3.32 ηg/mL of 1,9-dimethylmethylene blue (DMMB) as photosensitizer associated with the use of either Laser (λ660 nm) or LED (λ632 ±â€¯2 nm) using different energy densities (6, 12 and 18 J/cm2) to kill E. faecalis in vitro. Under different experimental conditions, 14 study groups, in triplicate, were used to compare the efficacy of the aPDT carried out with either the laser or LED lights using different energy densities associated to DMMB. The most probable number method (MPN) was used for quantitative analysis. Photodynamic antimicrobial effectiveness was directly proportional to the energy density used, reaching at 18 J/cm2, 99.999998% reduction of the counts of E. faecalis using both light sources. The results of this study showed that the use of 3.32 ηg/mL of DMMB associated with the use 18 J/cm2 of LED light (λ632 ±â€¯2 nm) reduced >7-log counts of planktonic culture of E. faecalis.

A novel technique of antimicrobial photodynamic therapy - aPDT using 1,9-dimethyl-methylene blue zinc chloride double salt-DMMB and polarized light on Staphylococcus aureus.

Antimicrobial Photodynamic Therapy (aPDT) is an alternative to conventional treatments of local infections such as the use of antibiotics, which may lead to the development of resistance. aPDT besides requiring the use of a photosensitiser also needs a light source do be carried out. In the search for efficient and low-cost procedure the use of multispectral polarized light (λ400-2000 nm) emerges as a possibility for the execution of aPDT. The use of a highly effective photosensitizer is also of great importance. 1,9-Dimethyl-Methylene Blue Zinc Chloride Double Salt - DMMB is a potent phenothiazine derivative that presents high photodynamic action due to its high lipophilicity as well as a greater quantum yield of Singlet oxygen and phototoxicity when compared to other Photosensitizers. The aim of this study was to assess, In Vitro, the efficacy of aPDT on Staphylococcus aureus (ATCC 25923) using different concentrations of DMMB associated to a Polarized light source (Bioptron®, 40 mW, ᴓ = 15.8 cm2) using different energy densities. Based on the IC50, 150 and 300 ng/mL of DMMB concentrations were chosen for this study. Twelve experimental groups were used: (Control, PLs, PSs and aPDTs). Serial dilutions (up to 10-8) of the bacterial inoculum were used and the DMMB was added using the two previously determined concentrations. After 5 min of preincubation the dilutions of the inoculum were illuminated by the polarized light source. Subsequently, 100 µL of each dilution, in triplicate, were inoculated into Petri dishes containing TSA medium and incubated in a bacteriological oven at 37 °C for 24-h and quantification of UFCs was done. The results showed significant exponential reduction (p < .0001) of 99.93% (150 ng/mL + LP 10 J/cm2) and 99.97% (300 ng/mL + LP 5 J/cm2) the CFU counts in comparison to non-illuminated control. The results of this study allow to conclude that aPDT carried out with 1,9-Dimethyl-Methylene Blue Zinc Chloride Double Salt-DMMB and a PL souce was efficacious on the reduction (99.97%), in vitro, of the bacterial counts of S. aureus.

The potential impact of using a surfactant and an alcoholic co-surfactant on SRB activity during EOR.

Surfactants and co-surfactants play an important role in enhanced oil recovery for they improve petroleum solubility and reduce interfacial tensions between oil, water and the rock formation. Ethanol is receiving renewed attention as potential co-surfactant because of the negative results obtained with the use of salts and alkaline substances. Sulphate-reducing bacteria (SRB) can use surfactants and co-surfactants as carbon sources and, consequently, this can increase the biological accumulation of sulphide (souring). The aim of this research is to correlate SRB activity with different concentrations of co-surfactant (ethanol) as an attempt to quantifying in which concentration such compound can potentially increase or inhibit souring. The results show that the combination of surfactant (lauryl glucoside) and co-surfactant (ethanol) can increase SRB activity to about 2.3-fold. The highest sulphate consumption rate of 591 µg l-1 h-1 was observed in experiments with 0.03% and 1.5% (v/v) of surfactant and ethanol, respectively. The experiments indicated that SRB activity is only controlled by ethanol concentrations above 6.5% (v/v). Ethanol can potentially decrease costs with the use of biocides and significantly increase oil recovery ratios. Tests with the model Desulfovibrio vulgaris were not comparable with the results obtained with the SRB consortium.

Pharmacophore and structure-based drug design, molecular dynamics and admet/tox studies to design novel potential pad4 inhibitors.

We have used docking (GLIDE), pharmacophore modeling (Discovery Studio), long trajectory molecular dynamics (Discovery Studio) and ADMET/Tox (QikProp and DEREK) to investigate PAD4 in order to determine potential novel inhibitors and hits. We have carried out virtual screening in the ZINC natural compounds database. Pharmacokinetics and Toxicity of the best hits were assessed using databases implemented in softwares that create models based on chemical structures taking into account consideration about the toxicophoric groups. A wide variety of pharmaceutical relevant properties are determined in order to make decisions about molecular suitability. After screening and analysis, the 6 most promising PAD4 inhibitors are suggested, with strong interactions (pi-stacking, hydrogen bonds, hydrophobic contacts) and suitable pharmacotherapeutic profile as well.

Effects of photostimulation on the catabolic process of xenobiotics.

Light biotechnology is a promising tool for enhancing recalcitrant compounds biodegradation. Xenobiotics can cause a significant impact on the quality of the results achieved by sewage treatment systems due to their recalcitrance and toxicity. The optimization of bioremediation and industrial processes, aiming to increase efficiency and income is of great value. The aim of this study was to accelerate and optimize the hydrolysis of Remazol Brilliant Blue R by photo stimulating a thermophilic bacterial consortium. Three experimental groups were studied: control group; LED Group and Laser Group. The control group was exposed to the same conditions as the irradiated groups, except exposure to light. The samples were irradiated in Petri dishes with either a Laser device (λ660 nm, CW, θ = 0.04 cm2, 40 mW, 325 s, 13 J/cm2) or by a LED prototype (λ632 ±â€¯2 nm, CW, θ = 0.5 cm2, 145 mW, 44 s, 13 J/cm2). We found that, within 48-h, statistically significant differences were observed between the irradiated and the control groups in the production of RNA, proteins, as well as in the degradation of the RBBR. It is concluded that, both Laser and LED light irradiation caused increased cellular proliferation, protein production and metabolic activity, anticipating and increasing the catabolism of the RBBR. Being the economic viability a predominant aspect for industrial propose our results indicates that photo stimulation is a low-cost booster of bioprocesses.

Photobiological effect of Laser or LED light in a thermophilic microbial consortium.

Cellulose has a highly diversified architecture and its enzymatic complexes are studied for achieving an efficient conversion and a high level of efficiency in the deconstruction of cellulolytic biomass into sugars. The aim of this investigation was to evaluate the effect of Laser or LED light in the cellulolytic activity (CMCase) and on the proliferation of the thermophilic microbial consortium used on the degradation process of a lignocellulosic biomass of green coconut shell. The irradiation protocol consisted of six Laser irradiations (λ660 ηm, 40 mW, 270 s, 13 J/cm2) or LED (λ632 ±â€¯2 ηm, 145 mW, 44 s, 13 J/cm2) with 12- h time intervals in nutrient deprivation conditions. After irradiation, the consortium was inoculated into a lignocellulosic biomass (coconut fibers). Non- irradiated consortium was also inoculated and acted as control. Cell proliferation and endoglucanase activity were quantified during the experimental time. Experiments were carried out in triplicate. The results showed an increase of 250 % of thermo-cellulolytic microorganisms for the LED group and 200% for the Laser group when compared to the control. The enzymatic index (red Congo method), showed a statistically significant difference in the process of degradation of the lignocellulosic biomass between the Laser and LED groups compared to the control group [p < 0.0029; p < 0.029, respectively] 48-hs after the inoculation of the microorganisms. At the end of 72-h, this significant difference was maintained for both irradiated groups (p < 0.0212). Based upon the protocol used on the present study, it is possible to concluded that LED light enhanced cell proliferation of the thermophilic microbial consortium while the Laser light increase the enzymatic index of the lignocellulosic biomass of green coconut shell.

Effects of PACT using phenothiazine-derived drugs and red light on the macrophage x S. aureus interface.

The aim of this study was to evaluate the lethal potential of macrophages infected with Staphylococcus aureus after PACT (Photochemical Antimicrobial Chemotherapy) using phenothiazine derivatives (a solution containing 1:1 methylene blue and O toluidine blue) and laser (660 nm, 40 mW, 60 s, 12 J/cm2) or LED (632 ±â€¯2 nm, 145 mW, 40 s, 12 J/cm2). Six experimental groups were evaluated: Control Group (untreated); Photosensitizer group (phenothiazines - 12.5 µg/mL); Laser Group; LED Group; Laser PACT Group; and LED PACT Group. The pre-irradiation time used in this study was 5 min. Macrophages and bacteria were cultured in specific culture media and/or allowed interaction between the cell types. Subsequently, tests were carried out to evaluate microbial proliferation, ROS production by macrophages and survival capacity of S. aureus after phagocytosis. Fluorescence microscopy assays were performed with the H2DCFDA probe, after PACT, at the initial time (0 h), 4-h and 12-h. The tests were performed in triplicate and the statistical test used was ANOVA with Tukey post-test. After PACT, a statistically significant difference (p > 0.0001) was observed between the microbial growth of the control group and the PACTs groups. Laser PACT and LED PACT groups presented, respectively, reductions of 84.2% and 81.5% when compared to control and 53.3% and 46% when compared to the photosensitizer group. It is concluded that the therapeutic protocols presented in this study increased the phagocytic capacity, the response rate of the phagocytes and the consequent reduction of the numbers of S. aureus for both PACT protocols, however the increase in ROS production was only observed in the group irradiated with Laser light.

Photodynamic Antimicrobial Chemotherapy (PACT) in osteomyelitis induced by Staphylococcus aureus: Microbiological and histological study.

Osteomyelitis is an inflammation either of medullar spaces or of the surface of cortical bones, which represents a bacterial infection. Photodynamic Antimicrobial Chemotherapy (PACT) is a treatment based on a cytotoxic photochemical reaction that induces a series of metabolic reactions and culminates in bacterial suppression. Such effect led to the idea that it could be used as a treatment of osteomyelitis. Following approval by the Animal Experimentation Committee of the School of Dentistry of the Federal University of Bahia, the present randomized study used eighty Wistar rats with the aim to evaluate, by microbiological and histological analysis, the effects of Photodynamic Antimicrobial Chemotherapy - PACT on tibial surgical bone defects in rats infected by Staphylococcus aureus. The animals were divided in groups: Control (non-infected); Control Osteomyelitis Induction; Saline solution; Photosensitizer; Red Laser and PACT - on this group, a diode laser (40mW; λ660nm ∅=0.04cm(2), CW, 10J/cm(2)) was used in combination with 5µg/ml of toluidine blue as the photosensitizer. On the microbiological study, immediately after treatment, the PACT group presented a bacterial reduction of 97.4% (p<0.001). Thirty days after treatment, there was a bacterial reduction of more than 99.9% (p<0.001). In the histological study, it was observed that the PACT group demonstrated an intense presence of osteocytes and absence of bone sequestration and micro-abscesses. The PACT using toluidine blue was effective in reducing the number of S. aureus enabling a better quality bone repair.

Souring control in fluid samples of oil industry using a multiple ligand simultaneous docking (MLSD) strategy.

We have used docking techniques in order to propose potential inhibitors to the enzymes adenosine phosphosulfate reductase and adenosine triphosphate sulfurylase that are responsible, among other deleterious effects, for causing souring of oil and gas reservoirs. Three candidates selected through molecular docking revealed new and improved polar and hydrophobic interactions with the above-mentioned enzymes. Microbiological laboratory assays performed subsequently corroborated the results of computer modelling that the three compounds can efficiently control the biogenic sulfide production.

Novel potential inhibitors for adenylylsulfate reductase to control souring of water in oil industries.

The biogenic production of hydrogen sulfide gas by sulfate-reducing bacteria (SRB) causes serious economic problems for natural gas and oil industry. One of the key enzymes important in this biologic process is adenosine phosphosulfate reductase (APSr). Using virtual screening technique we have discovered 15 compounds that are novel potential APSr inhibitors. Three of them have been selected for molecular docking and microbiological studies which have shown good inhibition of SRB in the produced water from the oil industry.

A new preclinical approach for treating chronic osteomyelitis induced by Staphylococcus aureus: in vitro and in vivo study on photodynamic antimicrobial therapy (PAmT).

Osteomyelitis is an acute or chronic inflammation in the marrow spaces in the superficial or cortical bone, and can be associated with bacterial or fungal infections. Chronic osteomyelitis represents a major health problem due to its difficult treatment and increased morbidity. Photodynamic antimicrobial therapy (PAmT) is a treatment based on a cytotoxic photochemical reaction in which a bright light produced by a laser system and an active photosensitizer absorbed by cells leads to a process of activation that induces a series of metabolic reactions that culminates a bacterial killing. The aim of the present randomized study was to evaluate, by in vitro and in vivo microbiological analysis, the effects of PAmT on tibial surgical bone defects in rats infected by Staphylococcus aureus using bacterial counts carried out immediately and after 30 days after treatment as outcome measure. In the preliminary in vitro study, a diode laser (λ660 nm; 40 mW; ϕ = 0.4 cm(2); 5 or 10 J/cm(2)) and 5, 10, and 15 µg/mL toluidine blue were tested, and the best parameter was chosen for the in vivo study. The concentration of 5 µg/mL was selected to perform the decontamination of S. aureus-infected tibial bone defects in rats. The findings were subjected to statistical analysis. For all PAmTs groups, with the different concentrations, treatment showed significant reductions (p < 0.001) in the amount of bacteria. The in vivo study PAmT group presented a bacterial reduction of 97.4% (p < 0.001). The PAmT using toluidine blue was effective in reducing the number of S. aureus in both in vitro and in vivo studies.

Growth of Chlorella vulgaris on sugarcane vinasse: the effect of anaerobic digestion pretreatment.

Microalgae farming has been identified as the most eco-sustainable solution for producing biodiesel. However, the operation of full-scale plants is still limited by costs and the utilization of industrial and/or domestic wastes can significantly improve economic profits. Several waste effluents are valuable sources of nutrients for the cultivation of microalgae. Ethanol production from sugarcane, for instance, generates significant amounts of organically rich effluent, the vinasse. After anaerobic digestion treatment, nutrient remaining in such an effluent can be used to grow microalgae. This research aimed to testing the potential of the anaerobic treated vinasse as an alternative source of nutrients for culturing microalgae with the goal of supplying the biodiesel industrial chain with algal biomass and oil. The anaerobic process treating vinasse reached a steady state at about 17 batch cycles of 24 h producing about 0.116 m(3)CH4 kgCODvinasse (-1). The highest productivity of Chlorella vulgaris biomass (70 mg l(-1) day(-1)) was observed when using medium prepared with the anaerobic digester effluent. Lipid productivity varied from 0.5 to 17 mg l(-1) day(-1). Thus, the results show that it is possible to integrate the culturing of microalgae with the sugarcane industry by means of anaerobic digestion of the vinasse. There is also the advantageous possibility of using by-products of the anaerobic digestion such as methane and CO2 for sustaining the system with energy and carbon source, respectively.

Molecular detection and genetic diversity of norovirus in hospitalized young adults with acute gastroenteritis in Bahia, Brazil.

The molecular epidemiology of a recent norovirus (NoV) outbreak in Brazil performed by comparative analysis with Genebank NoV sequences showed that the GII.4 strain was responsible for 72.5% of all NoV-positive cases (58/80). Other detected NoV strains included GII.3 (7/80; 8.8%) and GII.9 (8/80; 10%). This is the first outbreak reported in Bahia state, Brazil, during June-July of 2006, where NoV was identified as the principal etiologic agent in hospitalized young adults with acute gastroenteritis symptoms. These findings suggest that GII.4 is a predominant circulating genotype in NoV outbreaks in Brazil.

Ação moduladora da microbiota de portadores de síndrome de Down sobre bactérias cariogênicas / Modulating action of microbiota of carriers of Down’s syndrome on cariogenic microbiota

Os portadores da Síndrome de Down possuem baixa prevalência de cárie, apesar de apresentarem uma higiene oral deficiente. O estudo foi realizado para detectar cepas produtoras de bacteriocinas, com o intuito de avaliar a sua possível ação como moduladoras da microbiota cariogênica dos sindrômicos. Streptococcus mutans e Streptococcus sobrinus são os principais produtores de ácidos na cavidade oral. Em função disso, esses estreptococos foram testados antagonicamente com cepas isoladas dos indivíduos com Síndrome de Down, para que fosse avaliado se havia inibição das bactérias cariogênicas pelas cepas dos sindrômicos. Streptococcus mutans e Streptococcus sobrinus foram isolados utilizando o meio ágar sacarose bacitracina e identificados através de provas bioquímicas. Uma amostra de placa supragengival dos sindrômicos foi coletada e semeada por disseminação em Ágar Mitis-Salivarius, após o isolamento foram cultivados em caldo BHI. Dez culturas dos sindrômicos foram semeadas no Ágar Muller Hinton. Após o crescimento, as placas foram tratadas com clorofórmio. Sucessivamente, uma porção das culturas de bactérias cariogênicas foi transferida para meio semi-sólido BHI e vertidas nas placas com as culturas testes. Duas das dez cepas testadas apresentaram halo de inibição de crescimento contra cepas de Streptococcus mutans. A descoberta de cepas que produzem substâncias antimicrobianas pode ser responsável pela baixa prevalência de cárie em indivíduos com Síndrome de Down. Esse achado pode ajudar a entender a relação entre microbiota oral e patologia da cárie dentária.

Microbiota estreptocócica associada com a formação inicial da placa dental / Streptococci microbiota associated with initial formation of dental plaque

A identificação e quantificação dos estreptococos que iniciam a colonização das superfícies dos dentes no biofilme complexo da placa dental, bem como a compreensão das relações funcionais entre eles e outros membros são fundamentais para avaliar e, possivelmente, controlar os processos que essa comunidade inicial desempenha. Placas bacterianas foram assepticamente removidas de dentes de pessoas sadias e experimentalmente inoculadas em unidades dentárias esterilizadas e previamente cobertas com fluido oral estéril. Cada unidade dentária (UD) inoculada foi incubada a 37°C em uma câmara úmida. Após a formação da placa, a UD foi colocada em uma solução desagregadora da placa (SD) constituída de 0,1 por cento de água peptonada, 0,1 por cento de tween 80 e 0,5 por cento de areia calcinada (p/v). A UD foi submetida sucessiva e progressivamente à agitação em cinco velocidades controladas. Imediatamente após cada agitação, alíquotas foram coletadas e diluídas em tampão fosfato estéril, pH 7,2. Após cada coleta das alíquotas e antes de nova agitação, a UD era lavada em solução PBS estéril e novamente imersa em nova SD. Experimentos in vivo foram também efetuados, em unidades dentárias recentemente extraídas, usando a mesma técnica. Alíquotas das diluições foram semeadas na superfície de meios apropriados por disseminação usando uma alça de Drigalsky. As placas foram incubadas a 37°C em anaerobiose por 48 horas, quando, então, efetuavam-se as contagens total e diferencial das colônias. Cada tipo colonial era subcultivado e submetido a testes padrões para identificação bacteriana. De um total de 86 culturas de Streptococcus estudadas, 40,7 por cento foram identificadas como S. sanguis, 37,2 por cento como S. oralis, 8,1 por cento como S. mutans, 7,0 por cento como S. gordonii e 7,0 por cento como outros estreptococos. Análises das culturas isoladas da última velocidade de agitação mostraram que, nos experimentos in vitro, somente S. oralis (66,7 por cento) e S. sanguis...

Listeria monocytogenes: importância e distribuiçäo nos alimentos / Listeria monocytogenes: importance and distribution in the victuals

Listeria monocytogenes é uma bactéria Gram positiva, patogênica, cuja transmissäo, amplamente reconhecida, se dá através de alimentos contaminados. A listeriose está associada primariamente com alimentos processados prontos para consumo. A maioria dos surtos e casos esporádicos de listeriose envolve pessoas com deficiência imunológica, mulheres grávidas e seus fetos, recém-nascidos e idosos. Devido à severidade das infecçöes produzidas, vários países do mundo têm adotado uma política severa para o controle desse microrganismo. No entanto, o seu controle é difícil devido principalmente à sua distribuiçäo ubíqua, natureza psicrotrófica e tolerância a muitos agentes preservativos. Além disso, é necessário desenvolver um método mais conveniente para detectar L.monocytogenes.

Avaliaçäo e controle da qualidade microbiológica de mäos de manipuladores de alimentos / Microbial evaluations and control workers' hands

Foi conduzido monitoramento microbiológico das mäos de manipuladores de alimentos como parte de um estudo para implantaçäo do Sistema de Análise de Perigos e Pontos Críticos de Controle em um restaurante institucional, através da contagem padräo de aeróbios mesófilos e anaeróbios facultativos, S. aureus, C. perfringens e presença de Salmonella spp. Foram observadas contagens de microrganismos aeróbios mesófilos e anaeróbios facultativos em níveis de até 10 7 UFC/mäo, contaminaçöes por S. aureus e C. perfringens e oportunidades de contaminaçäo cruzada por essas mäos principalmente no fatiamento da carne assada. Salmonella spp. näo foram isoladas. Foram adotadas medidas corretivas para este ponto crítico de controle, constatando de lavagem das mäos dos manipuladores com água corrente e sabonete líquido neutro seguida de antissepsia com iodóforo. Foram observadas reduçöes da contagem de aeróbios mesófilos em até 2,6 ciclos log e, apesar desta reduçäo näo ser a ideal, ela demonstra a contribuiçäo que esta prática pode trazer aos serviços de alimentaçäo, além do que näo foram mais detectados microrganismos patogênicos como S. aureus e C. perfringens