Nelma de Mello Silva Oliveira

Microbial profile of a kefir sample preparations - grains in natura and lyophilized and fermented suspension

Probiotics are supplementary foods developed by microbial strains that improve animal health beyond basic nutrition. Probiotics are consumed orally, regardless of being considered as normal inhabitants of the intestines, able to survive in enzimatic and biliary secretions. Kefir is a probiotic originated from the old continent, fermented by several bacteria and yeasts, encapsulated in a polyssacharide matrix, and resembles jelly grains. Kefir is also presented as its sourish product both in sugary or milky suspensions containing vitamins, aminoacids, peptides, carbohydrates, ethanol, and volatile compounds. Kefir is known to have a diverse microbial content depending on the country and fermentative substrates, which cause distinct probiotic effects. In this sense, the purpose of this work was to isolate, identify, and quantify the microbial content of a native sugary kefir sample (fermented suspension and lyophilized natural grains). Serial dilutions were plated on Rogosa agar (AR) and De Man, Rogosa and Sharpe (MRS), for Lactobacillus; Brain Heart Infusion (BHI), for total bacteria; Sabouraud-Dextrose-Agar (SDA), for yeasts and filamentous fungi; Thioglycolate Agar (TA), for Streptococcus, Acetobacteria and Leuconostoc; and Coconut Water Agar (CWA), and CWA supplemented with yeast extract (CWAY), for various genera. Genera and species for all strains were identified through biochemical reactions and specific API systems. The microbial profile of kefir was different from other sources of grains despite the presence of similar microorganisms and others which have not been reported yet. The data obtained with the CWA and CWAE media suggest that both substrates are alternative and salutary media for culture of kefir strains.

Ozônio e ultra-som: processos alternativos para o tratamento do café despolpado

There is a growing interest in technologies that improve food quality, as well as food safety aspects. After water, coffee is the most consumed beverage in the planet, with a rising demand for special types, such as fermented coffee, in some importing countries. This type of coffee is obtained by removing the mucilage, submitting the coffee to fermentation, a process that varies with the climate and the associated natural micro-organisms, among other factors, and that can lead to detrimental effects to the quality of the product and to the health of consumers. Thus, it is necessary to investigate new technologies that can help obtain better standardized products, of higher quality and that offer greater food safety. Ozone and ultrasound are technologies used in various areas, with great flexibility and promising results in the production and treatment of an infinity of food products. The potent oxidant and antimicrobial characteristics of both are well-known, however, their mechanisms are still not clearly understood when used in live tissues. Their effects on the various quality parameters must be studied, understood and adjusted, before widespread use in the food industry. In the present paper, ozone or ultrasound were applied as pre-treatments before coffee fermentation, demonstrating their efficacy in improving food safety of the fermented coffee, without perceptible changes in the quality of the beverage.

Disparity between Multilocus Enzyme Electrophoresis, Microsatellite Markers and Pulsed-Field Gel Electrophoresis in epidemiological tracking of Candida albicans

Various molecular systems are available for epidemiological, genetic, evolutionary, taxonomic and systematic studies of innumerable fungal infections, especially those caused by the opportunistic pathogen C. albicans. A total of 75 independent oral isolates were selected in order to compare Multilocus Enzyme Electrophoresis (MLEE), Electrophoretic Karyotyping (EK) and Microsatellite Markers (Simple Sequence Repeats - SSRs), in their abilities to differentiate and group C. albicans isolates (discriminatory power), and also, to evaluate the concordance and similarity of the groups of strains determined by cluster analysis for each fingerprinting method. Isoenzyme typing was performed using eleven enzyme systems: Adh, Sdh, M1p, Mdh, Idh, Gdh, G6pdh, Asd, Cat, Po, and Lap (data previously published). The EK method consisted of chromosomal DNA separation by pulsed-field gel electrophoresis using a CHEF system. The microsatellite markers were investigated by PCR using three polymorphic loci: EF3, CDC3, and HIS3. Dendrograms were generated by the SAHN method and UPGMA algorithm based on similarity matrices (S(SM)). The discriminatory power of the three methods was over 95%, however a paired analysis among them showed a parity of 19.7-22.4% in the identification of strains. Weak correlation was also observed among the genetic similarity matrices (S(SM)(MLEE)xS(SM)(EK)xS(SM)(SSRs)). Clustering analyses showed a mean of 9+/-12.4 isolates per cluster (3.8+/-8 isolates/taxon) for MLEE, 6.2+/-4.9 isolates per cluster (4+/-4.5 isolates/taxon) for SSRs, and 4.1+/-2.3 isolates per cluster (2.6+/-2.3 isolates/taxon) for EK. A total of 45 (13%), 39 (11.2%), 5 (1.4%) and 3 (0.9%) clusters pairs from 347 showed similarity (S(J)) of 0.1-10%, 10.1-20%, 20.1-30% and 30.1-40%, respectively. Clinical and molecular epidemiological correlation involving the opportunistic pathogen C. albicans may be attributed dependently of each method of genotyping (i.e., MLEE, EK, and SSRs) supplemented with similarity and grouping analysis. Therefore, the use of genotyping systems that give results which offer minimum disparity, or the combination of the results of these systems, can provide greater security and consistency in the determination of strains and their genetic relationships.

Evaluation of the mutagenicity and antimutagenicity of Ziziphus joazeiro Mart. bark in the micronucleus assay

The aim of this study was to evaluate the mutagenicity (clastogenicity/aneugenicity) of a glycolic extract of Ziziphus joazeiro bark (GEZJ) by the micronucleus assay in mice bone marrow. Antimutagenic activity was also assessed using treatments associated with GEZJ and doxorubicin (DXR). Mice were evaluated 24–48 h after exposure to positive (N-nitroso-N-ethylurea, NEU - 50 mg.kg−1 and DXR - 5 mg.kg−1) and negative (150 mM NaCl) controls, as well as treatment with GEZJ (0.5–2 g.kg−1), GEZJ (2 g.kg−1) + NEU and GEZJ (2 g.kg−1) + DXR. There were no significant differences in the frequencies of micronucleated polychromatic erythrocytes in mice treated with GEJZ and GEJZ + DXR compared to the negative controls, indicating that GEZJ was not mutagenic. Analysis of the polychromatic:normochromatic erythrocyte ratio revealed significant differences in the responses to doses of 0.5 g.kg−1 and 1–2 g.kg−1 and the positive control (NEU). These results indicated no systemic toxicity and moderate toxicity at lower and higher doses of GEZJ. The lack of mutagenicity and systemic toxicity in the antimutagenic assays, especially for treatment with GEZJ + DXR, suggested that phytochemical compounds in Z. joazeiro bark attenuated DXR-induced mutagenicity and the moderate systemic toxicity of a high dose of Z. joazeiro bark (2 g.kg−1). Further studies on the genotoxicity of Z. joazeiro extracts are necessary to establish the possible health risk in humans and to determine the potential as a chemopreventive agent for therapeutic use.

Efeito anti-inflamatório da lipoproteína de alta densidade no sistema cardiovascular de camundongos hiperlipidêmicos

Resumo Fundamento Camundongos knouckout para o gene do receptor de lipoproteina de baixa densidade (LDLr−/−) sao hiperlipidemicos espontâneos e resistentes ao desenvolvimento de lesoes neointimais. Objetivos O presente estudo teve como objetivo determinar o fator que previne o processo inflamatorio, as lesoes neointimais cardiovasculares e a resistencia insulinica nos camundongos LDLr−/−. Material e metodos Utilizaram-se tres grupos experimentais de camundongos machos com tres meses de idade: Grupo WT, camundongos selvagens; Grupo S, camundongos LDLr−/− que receberam racao padrao; Grupo HL, camundongos LDLr−/− que receberam racao hiperlipidica. Apos 15 dias, o sangue foi coletado para analise plasmatica dos lipideos, glicose e insulina. O indice de Homa foi calculado para determinar a resistencia a insulina. O coracao e aorta foram removidos e processados histologicamente. Cortes histologicos do coracao foram processados imunoistoquimicamente com anticorpo anti-CD40L para avaliar a presenca de processo inflamatorio. Cortes histologicos das arterias foram corados com hematoxilina/eosina e picrosirius red para avaliar alteracoes morfologicas e morfometricas. Resultados Os camundongos S foram resistentes ao processo inflamatorio, caracterizado por baixa imunorreatividade para o CD40L, com niveis plasmaticos de HDL elevados, e nao desenvolveram resistencia insulinica, mesmo com hiperlipidemia moderada em relacao aos WT. Os camundongos HL apresentaram uma hiperlipidemia grave, aumento na imunorreatividade cardiaca para o CD40L, pronunciadas alteracoes morfologicas na parede da aorta e resistencia insulinica, associadas a um decrescimo nos niveis plasmaticos do HDL em relacao aos S. Esta hiperlipidemia grave dos camundongos HL pode ser considerada o fator metabolico indutor do maior estresse oxidativo no sistema cardiovascular, aumentando a peroxidacao lipidica da molecula de HDL e consequentemente sua remocao hepatica, com consequente diminuicao dos niveis plasmaticos do HDL. Conclusao O nivel plasmatico elevado de HDL e o fator protetor contra o desenvolvimento de processos inflamatorios cardiovasculares e resistencia insulinica nos camundongos LDLr−/−, impedindo o desenvolvimento das lesoes neointimais.

In vitro mutagenicity assay (Ames test) and phytochemical characterization of seeds oil of Helianthus annuus Linné (sunflower)

The objective of this research was to investigate the genotoxic potential of the oil of H. annuus L. (sunflower) seeds via the Ames test as well as its oxidative properties and lipid composition. The pre-incubation method, system metabolic activation (S9 fraction) and five S. typhimurium strains (TA97, TA98, TA100, TA1535 and TA102) were employed for the Ames test. The oxidative stability and fatty acid composition were analyzed by standard methods and gas chromatography. A revertant analysis showed no significant differences between the treatment doses (10–200 μl/plate) and the negative controls, regardless of S9+ and S9−, and included all of the S. typhimurium strains. Chromatographic analysis showed high levels of polyunsaturated fatty acids, followed by monounsaturated, saturated and total trans-isomers. Among the polyunsaturated, monounsaturated and saturated fatty acids, linoleic, oleic and palmitic acids predominated. The results suggest that the sunflower oil is not genotoxic as indicated by frameshift mutations and base pair substitutions regardless of the treatment dose, but shows dose-dependent toxicity. The oxidative properties of the sunflower oil were consistent with the requirements of national and international standards. However, its composition could also indicate phytotherapeutic properties.

Características microbiológicas e físico-químicas do leite de cabra submetido à pasteurização e ao congelamento, comercializado na cidade de Alfenas-MG doi: http://dx.doi.org/10.5892/ruvrv.2013.111.224233

Demand for goat milk has increased in Brazil along the years. This food represents a high quality protein and calcium resource besides being an alternative for individuals who are allergic to cow milk. However, it is highly susceptible to contamination and subjected to fraud. Therefore, this paper was aimed at verifying the quality of goat milk commercialized in Alfenas, Minas Gerais, and at evaluating the effect of pasteurization and of freezing on its microbiological and physicochemical characteristics. Microbiological and physicochemical analysis were carried out in three lots of raw, pasteurized and pasteurized-frozen goat milk for 90 days, during 9 months, a milk-lot being purchased every 90 days. Data obtained underwent analysis of variance and Turkey test (p<0.05). It was observed that pasteurization was efficient to improve microbiological quality of milk, which was kept by freezing. Physicochemical characteristics were in accordance with legislation and pasteurization and freezing for 90 days did not alter them. It was concluded that goat milk commercialized in Alfenas, Minas Gerais presents microbiological and physicochemical qualities within the standards established by legislation and that pasteurization and freezing did not interfere with those qualities.

Anti-inflammatory effect of high-density lipoprotein on the cardiovascular system of hyperlipidemic mice

Abstract Introduction LDLr-/- mice are spontaneously hyperlipidemic and resistant to the development of neointimal lesions. Objectives This study aimed to determine the factor that prevents the inflammatory process and neointimal lesions and insulin resistance in LDLr-/- mice. Methods Three groups of 3-month-old male mice were used: wild-type mice (WT group); LDLr-/- mice fed a standard diet (S group); and LDLr-/- mice fed a high-fat diet (HF group). After 15 days, blood was collected for analysis of plasma lipids, glucose and insulin. The HOMA index was calculated to determine insulin resistance. The heart and aorta were removed for histological study. Histological sections of the heart were processed immunohistochemically with anti-CD40L antibodies to evaluate the inflammatory process. Histological sections of the aorta were stained with hematoxylin/eosin and picrosirius red to assess morphological and morphometric alterations. Results The S mice were resistant to the inflammatory process, as shown by low immunoreactivity to CD40L, with high plasma HDL levels, and did not develop insulin resistance, even with moderate hyperlipidemia compared to WT. The HF mice showed severe hyperlipidemia, increased cardiac immunoreactivity to CD40L, pronounced morphological changes in the aortic wall and insulin resistance, associated with a decrease in plasma HDL levels, compared to S. This severe hyperlipidemia in the HF mice can be considered the major metabolic factor inducing oxidative stress in the cardiovascular system, increasing the lipid peroxidation of HDL and hence its removal by the liver, with consequent lowering of plasma HDL levels. Conclusion High HDL plasma levels are a protective factor against the development of cardiovascular inflammation and insulin resistance in LDLr-/- mice, preventing the development of neointimal lesions.

Determination of the antimicrobial activity in the hydroalcoholic extract of the plant Plectranthus ornatus Codd (Bilberry Chinese)

Plectranthus ornatus Codd is a plant from Mediterranean and Near East countries. It is indicated for liver illnesses and digestion problems in popular medicine. It is used in the treatment for the control of gastritis, dyspepsia, heartburn, gastric discomfort, and hangover. This study aims to evaluate the antimicrobial activity in extracts of P. ornatus using 15 standardized micro-organisms. Antimicrobial tests were performed on Mueller Hinton agar through the technique of wells. Broth microdilution tests were used for the determination of the minimum inhibitory concentration (MIC), and seeding on plates containing Mueller Hinton agar for the determination of the minimum microbicide concentration (MMC). The broth microdilution tests demonstrated that the extract inhibited the growth of Bacillus cereus, Streptococcus pyogenes, and Enterococcus faecalis at the concentrations of 20.31, 325, and 650 mg/mL, respectively. The microdilution tests showed growth inhibition of Saccharomyces cerevisiae at a concentration of 1,300 mg/mL. The extract did not show inhibitory activity on the other tested strains. As a result of increased multiple resistances to antibiotics, microbial research in the development of new drugs that are economically viable and offer an effective safety margin have won space in the scientific community.