Diversity of Lactic Acid Bacteria Isolated from Brazilian Water Buffalo Mozzarella Cheese

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Covalent immobilization of laccase in green coconut fiber and use in clarification of apple juice

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sub-MICs of Mentha piperita essential oil and menthol inhibits AHL mediated quorum sensing and biofilm of Gram-negative bacteria

Bacterial quorum sensing (QS) is a density dependent communication system that regulates the expression of certain genes including production of virulence factors in many pathogens. Bioactive plant extract/compounds inhibiting QS regulated gene expression may be a potential candidate as antipathogenic drug. In this study anti-QS activity of peppermint (Menthe piperita) oil was first tested using the Chromobacterium violaceum CVO26 biosensor. Further, the findings of the present investigation revealed that peppermint oil (PMO) at sub-Minimum Inhibitory Concentrations (sub-MICs) strongly interfered with acyl homoserine lactone (AHL) regulated virulence factors and biofilm formation in Pseudomonas aeruginosa and Aeromonas hydrophila. The result of molecular docking analysis attributed the QS inhibitory activity exhibited by PMO to menthol. Assessment of ability of menthol to interfere with QS systems of various Gram-negative pathogens comprising diverse AHL molecules revealed that it reduced the AHL dependent production of violacein, virulence factors, and biofilm formation indicating broad-spectrum anti-QS activity. Using two Escherichia colt biosensors, MG4/pKDT17 and pEAL08-2, we also confirmed that menthol inhibited both the las and pqs QS systems. Further, findings of the in vivo studies with menthol on nematode model Caenorhabditis elegans showed significantly enhanced survival of the nematode. Our data identified menthol as a novel broad spectrum QS inhibitor.

Denture stomatitis--presence of bacteria and yeasts

The presence of yeasts and bacteria was studied in 26 patients with denture stomatites, and the results compared with the data of the normal mucosa foi edentoulous patients, who used or not upper dentures. The use of dentures caused an increase in the amount of yeasts, and there was a correlation with the severity of the stomatitis. Gram positives cocci and bacilus predominated in all studied groups, but in cases of stomatitis there was an increase in the amount of Gram negative cocci and filamentous. These results suggest that besides yeasts, modifications of the bacteria flora can be relevant for the development of denture stomatitis.

Formation of a ternary complex for selenocysteine biosynthesis in bacteria

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Nanocompósitos multifuncionas de fibroína reforçados com biocelulose

This work shows the preparation and characterization of the new nanocomposites based on fibroin and biocellulose. Bacterial cellulose (BC) is an exopolysaccharide produced by bacteria of the genus Gluconacetobacter, which it has identical chemical structure of the cellulose from plants and it has gained attention in the field of research for its unique properties as excellent mechanical properties when dry and hydrated , higher capacity of water retention, moldability , biodegradability and excellent biological affinity . Silk fibroin (SF) is a structural protein present in the cocoon of the silkworm, Bombyx mori, has been identified as suitable for developing optical devices, tissue engineering application, enzyme immobilization, controlled release drug agent biopolymer. Silk fibroin/bacterial cellulose nanocomposite films were prepared impregnating different cellulose charges (0.5 %, 1.0 %, 1.5 %, 2.5 %, 5.0 % and 10.0 %) weight/weight. According mechanical tests and water and Paynes's cup permeability showed that SF/BC 1% nanocomposite has the most relevant results. Poliethylenoglicol (PEG) containing SF films improved optical and mechanical properties when compared to pristine SF film. New SF/BC nanocomposites could be applied in Medicine, as biodegradable packaging and flexible substrates for OLEDs.

Study of physical-chemical stability in contaminated conditioners by bacteria

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation of the use of probiotic acid lactic bacteria in the development of chicken hambúrguer

The objective of this study was to investigate the effect of fermentation with Lactobacillus acidophilus CRL 1014 on the physicochemical, microbiological and sensory characteristics of a hamburger product like processed with chicken meat and okara flour, with reduction of curing salts. A mixture of ingredients containing 90% chicken meat and 10% okara flour was subjected to the following treatments: F1: fermented with Lactobacillus acidophilus; F2:75 mg nitrite/kg and fermented with Lactobacillus acidophilus; F3: 150 mg nitrite/kg and unfermented. The quality of the “hamburgers” was assessed by physical and chemical analysis (pH, cooking yield and shrinkage), chemical composition, microbiological tests (Salmonella spp., count of sulphite-reducing clostridia, staphylococos coagulase-positive, total coliforms and Escherichia coli) and sensory analysis (sensory acceptance and purchase intent). During the first six days of fermentation, there was a decrease in pH from approximately 6.33 to 5.10. All the samples showed the same chemical composition (p < 0.05). The fermentation process was observed to inhibit the multiplication of microorganisms of several groups: coagulasepositive staphylococci, sulphite-reducing clostridia, Salmonella spp. and E. coli. The different “hamburgers” formulations showed high scores for all the sensory attributes evaluated, without differing from each other (p < 0.05). The results showed that the use of L. acidophilus CRL 1014 enabled the production of a safe product, with good physicochemical and sensory characteristics, in the absence of curing salts.

Bacteria on the hands of school-age children at a Pediatric Hospitalization Unit

Objective. To estimate the prevalence of bacteria isolated in samples from the hands of school-age children at a hospitalization unit. Methodology. In 2009, strains were cultured from the hands of 90 school-age children at the pediatric hospitalization unit of Hospital Estadual Bauru (São Paulo, Brazil). After culture of the samples, the isolated bacteria were identified. Results. In 98% of the samples taken from the children, bacteria were isolated. Coagulase-negative Staphilococcus was isolated in 64% of the samples, followed by Staphilococcus aureus (5%) and Pseudomonas aeruginosa (1%). Conclusion. In most of the samples from the children’s hands, bacteria were isolated. Therefore, educative actions about hygiene habits in- and outside the hospital environment should be reinforced, aimed at children and their companions.

P-215-Quantitative variation of some gut bacteria in Crohn's disease can be related to the patient's gender

Background: Imbalance in bacterial species composition of the gut microbiota is one of the factors associated with the cause or complication of the symptoms of Crohn's disease (CD). This disequilibrium consists in the reduction of biodiversity, decrease of genus such as Bifidobacterium and elevation of species such as Escherichia coli. Human microbiota varies among subjects of a same population irrespective of their health condition and among individuals living in distinct geographic locations. In animal models, sex related differences could also be observed in gut bacterial species composition under some pathological conditions. Experiments conducted with mice have demonstrated that the manifestation of type 1 diabetes (T1D) could be under the influence of the animal sex and its serum level of testosterone, which in turn could be modulated by a particular gut microbiota. Considering the existence of similar features between T1D and CD, such as strong genetic component and malfunctioning of the immune system, we investigated whether differences could be observed in the gut microbiota dysbiosis of male and female CD patients. Methods: Fifty and 5 gut mucosal biopsies from 25 adult CD patients (11 males and 14 females) and 43 specimens of an equivalent clinical material from 22 control subjects (11 males and 11 females) were screened for bacterial biodiversity by analyzing sequences of 16SrDNA V6 region. A number of 2-3 samples each from distinct gut segments (from ileum to rectum) were taken from each subject. The 16SrDNA sequences were obtained by sequencing PCR amplicons of the corresponding gene in the Ion torrent PGM sequencer. Identification and classification of the bacterial groups followed the Ribosomal Database Project (RDP) website pipeline. The relationships of the bacterial taxa with each of the study parameters was performed by compiling the data in a MS Excel and the level of statistical significance determined by the Chi-square test. Results: A total of 3203 16SrDNA sequences were detected in the 98 biopsies samples, the majority of which matching Proteobacteria, Firmicutes, Bacterioidetes, and Actinobacteria. The percentage of DNA sequences for each of these phyla found in Male control subjects/Male CD patients was 40.5/33, 32.7/32.4, 20.8/24.5, and 4.4/4,4 for Proteobacteria, Firmicutes, Bacterioidetes, and Actinobacteria, respectively. In Female comparisons, these values were 35.6/42, 39.2/26.3, 19.8/23.3, 5.2/7. Both Male and Female CD patients presented higher numbers of sequences of Actinobacteria and Bacterioidetes than those of control subjects of the same gender. Case-control differences for Firmicutes could be observed only in female comparisons and, for Proteobacteria, although case-control differences were observed in both genders, the nature of difference was distinct, since while in CD female patients a higher number of sequences matching this phylum was detected, in males a reduced number was observed, in comparison with controls. The species responsible for the Proteobacteria variation in both gender was Escherichia coli. Conclusions: The data presented above suggest that any analysis of dysbiosis in CD must take in account the patient's gender, an observation particularly relevant for Escherichia coli, whose association with CD has been most intensively investigated and for which the present study shows a reverse quantitative variation regarding the patients' gender.

Nitrogen immobilization by Congo grass roots impairs cotton initial growth

In crop-livestock integration systems the presence of both grass roots in the soil and straw on the surface can temporarily immobilize nitrogen. This study examined the persistence of grass residues in the system as well as their effects on cotton response to N when grown after Congo grass (Brachiaria ruziziensis, Syn. Urochloa ruziziensis). Congo grass was grown in pots with soil. Next, cotton was grown in the same pots without residues, with whole plant residues (Congo grass roots and shoots) or root residues (grass roots) and fertilized with N as ammonium nitrate. Congo grass and cotton roots were separated using stable carbon isotope fractioning. Congo grass roots showed higher C/N ratio than shoots, losing 14% of its mass after 45 days and increasing soil N immobilization. The lower N availability resulted in N deficient and shorter cotton plants with lower dry matter yields. Nevertheless, the application of 80 to 120 mg kg-1 of N compensated the immobilization by the soil microorganisms, allowing cotton to show normal growth. When Congo grass is present in the cropping system, the effects of the decaying roots on soil N dynamics and availability are more important than those of the straw left on the soil surface.

Gamma irradiation can control the number of psychotrophic bacteria in Agaricus bisporus during storage

We evaluated the effect of gamma irradiation doses (0, 125, 250, and 500 Gy) in control of psychrotrophic bacteria in different strains of Agaricus bisporus (ABI-07/06, ABI-05/03, and PB-1) during storage, cultivated in composts based on oat straw (Avena sativa) and Brachiaria spp. The experimental design was completely randomized in a factorial scheme 4  2  3 (irradiation doses  composts  strains), with 24 treatments, each consisting of 2 replicates, totaling 48 experimental units (samples of mushrooms). The mushrooms collected from all culture conditions were packaged in plastic polypropylene with 200 g each and subjected to Cobalt-60 irradiator, type Gammacell 220, and dose rate 0.740 kGy h–1 , according to the treatments. Subsequently, the control (nonirradiated) and other treatments were maintained at 4 ± 1°C and 90% relative humidity (RH) in a climatic chamber to perform the microbiological analysis of mushrooms on the 1st and 14th day of storage. According to the results, it was found that the highest mean colony psychotrophic count, after 14 days of storage, was observed in strain ABI-07/06 1.30 × 108 g -1 most probable number (MPN) in nonirradiated mushrooms, coming from Brachiaria grass-based compost, and this same strain under the same storage conditions, coming from the same type of compost that underwent a dose of 500 Gy, obtained a significant reduction in mean colonies of psychrotrophic bacteria (2.25 × 104 g –1 MPN). Thus, the irradiation doses tested favored reducing the number of colonies of psychrotrophic bacteria, regardless of the type of compound and strain of A. bisporus.

MSNBC - Gold-plated bacteria

No Abstract

Immobilization of cholesterol oxidase in LbL films and detection of cholesterol using ac measurements

The preserved activity of immobilized biomolecules in layer-by-layer (LbL) films can be exploited in various applications. including biosensing. In this study, cholesterol oxidase (COX) layers were alternated with layers of poly(allylamine hydrochloride) (PAH) in LbL films whose morphology was investigated with atomic force microscopy (AFM). The adsorption kinetics of COX layers comprised two regimes, a fast, first-order kinetics process followed by a slow process fitted with a Johnson-Mehl-Avrami (JMA) function. with exponent similar to 2 characteristic of aggregates growing as disks. The concept based on the use of sensor arrays to increase sensitivity, widely employed in electronic tongues, was extended to biosensing with impedance spectroscopy measurements. Using three sensing units, made of LbL films of PAH/COX and PAHIPVS (polyvinyl sulfonic acid) and a bare gold interdigitated electrode, we were able to detect cholesterol in aqueous solutions down to the 10(-6) M level. This high sensitivity is attributed to the molecular-recognition interaction between COX and cholesterol, and opens the way for clinical tests to be made with low cost. fast experimental procedures. (C) 2008 Published by Elsevier B.V.

Influence of the use of Aliquat 336 in the immobilization procedure in sol-gel of lipase from Bacillus sp ITP-001

Aliquat 336, a liquid hydrophobic material, was used at different concentrations (0.5-3.0%, w/v) as an additive in the preparation of encapsulated lipase from Bacillus sp. ITP-001 on sol-gel silica matrices using tetraethoxysilane (TEOS) as the precursor. The resulting hydrophobic matrices and immobilized lipases were characterized with regard to specific surface area (BET method), adsorption-desorption isotherms, pore volume (Vp) and size (dp) by nitrogen adsorption (BJH method) and scanning electron microscopy (SEM). The catalytic activities and the corresponding coupling yields were assayed in the hydrolysis of olive oil. In comparison with pure silica matrices, the immobilization process in the presence of Aliquat 336 decreased the values for specific surface area and increased the values for pore specific volume (Vp) and mean pore diameter (dp). This behavior may be related to the partial adsorption of the enzyme on the external surface of the hydrophobic matrix as indicated by scanning electron microscopy. Aliquat 336 concentrations in the range from 0.5 to 1.5% (w/v) provided immobilized derivatives with higher coupling yields and better substrate affinity. The highest coupling yield (Y-A = 71%) was obtained for the immobilized enzyme prepared in the presence of 1.5% Aliquat which gave the following morphological properties: specific surface area = 183 m(2)/g, pore specific volume (Vp) = 0.36 cc/g and mean pore diameter (dp)= 91 angstrom. (c) 2012 Elsevier B.V. All rights reserved.