Prática Investigativa: experimentando o mundo da microbiologia

Dentro de uma imagem construtivista a experimentação apresenta características peculiares, como o uso de conhecimentos prévios, dialogo, reflexão, problematização, interdisciplinaridade, e relações ao cotidiano, apresentando-se como uma atividade de investigação, em que o aluno deve refletir, discutir, explicar e relatar, caracterizando assim uma investigação científica Este trabalho tem como objetivo promover aprendizagem significativa do conteúdo de microbiologia, considerado um conteúdo abstrato, através de atividades empíricas se utilizando do método por investigação, desmistificando a informação de que microrganismos são apenas agentes patogênicos ao focar ecologia e importância econômica de alguns desses seres, e sensibilizando quanto à importância da higienização correta dos alimentos ingeridos crus. Abordagem foi realizada no 2º ano do ensino médio em uma escola pública, conveniada ao PIBID/UFRN/Biologia. Concretizada pela aplicação de duas atividades experimentais baseadas na problematização: “Agora eu vi, realmente existem!” e “Comer, comer para poder crescer”. Os experimentos foram realizados em aulas diferentes e caracterizam-se em sensibilização da higienização de alimentos consumidos crus, e análise da função e importância econômica de alguns microrganismos. A exposição do estudante a um problema em que ele pode vivenciar no se dia-a-dia o encoraja a envolver-se no seu próprio processo de aprendizagem, além de orientá-lo a aplicar o conhecimento adquirido em situações práticas, desenvolvendo desta forma habilidades especificas que possibilitem a continuidade de sua educação. Concluímos então que utilização de atividades experimentais realizadas pelo método de investigação gera aprendizagem de procedimentos e atitudes, além da aprendizagem de conceitos/conteúdos.

Fatores que afetam a competitividade do queijo artesanal: um estudo exploratório no Seridó/RN

This article presents a study on the research of the factors that affect the competitiveness of cheese produced in a craft in the Seridó of Rio Grande do Norte in the perception of rural producers. His theory is based on factors of competitiveness and definitions of craft production. This research was performed in the important area of production and marketing of cheeses from the state. The methodology used was exploratory research descriptive type survey. The research field of 213 returned questionnaires validated. those interviewed were rural producers of artisanal cheese, with properties distributed in the districts located in the region. The results showed the production of artisanal cheese in Seridó / RN's main points of difficulty to compete: the great marketing in the informality, workforce has low skills and education, has little technical assistance, low acceptance by technological innovations and absence of integration between producers which creates low productivity and qualification of the production chain

Diagnóstico regional do processo de queijo coalho comercializado em Natal/RN

Coalho cheese is a typical product of the Northeastern Brazil, which is consumed both raw and cooked. The present work aimed to study the characteristics of artisanal and industrial processes in the production of coalho cheese sold in Natal / RN in order to evaluate its quality and consumer s profile. Four artisanal cheeses plants were monitored and a questionnaire was sent to different cheese industries. Besides this, eight cheese samples (four artisanal and four industrial) were evaluated in regard to the microbiological quality, physical-chemical and sensory attributes. The sensory acceptance was evaluated by using 108 non-trained panelists by using the hedonic scale. The consumer s profile survey was applied to 400 consumers of coalho cheese. The lack of hygiene control was detected at the artisanal cheese production, which uses raw milk as its raw material. Research has shown that the industrialized cheeses are made from pasteurized milk provided by their own production or by a third party, as observed in cheese making dairies. In general, the results indicate variation in the manufacturing process of coalho cheese, which results in the lack of product standardization. Regarding the physical-chemical analysis, most artisanal and industrial samples presented moisture content between 36 and 40 %, classified as medium moisture cheese, which is the only parameter that showed no significant difference (p>0.05). However, the water activity (Aw), pH and acidity results differed significantly. All artisanal samples showed coliform contamination at 35 °C, which confirms the poor hygienic conditions. In regard to coliforms at 45 °C, 75 % of artisanal coalho cheese samples had value higher than 103 MPN / g, a value above the lawful limits determined by RDC nº 12. Fifty percent of industrial coalho cheese samples showed coagulase-positive Staphylococcus values above the limit allowed by the RDC nº 12, indicating poor handling. The sensory evaluation revealed that the taste was the only parameter that showed significant difference, and this difference was only between two industrial brands. The consumer s survey showed that the coalho cheese flavor is the most important reason for buying this kind of cheese. Although coalho cheese is mainly bought in supermarkets, open street markets and country shops are still important selling points. It is concluded that there is no coalho cheese standardization in the RN state, which leads to variations in physical-chemical and sensory attributes. Moreover, it is necessary greater hygiene control in the production and handling procedures of coalho cheese.

Recuperação e purificação de proteínas do soro de queijo tipo coalho usando cromatografia de troca iônica e interação hidrofóbica em leito na forma expandida

Expanded Bed Adsorption plays an important role in the downstream processing mainly for reducing costs as well as steps besides could handling cells homogenates or fermentation broth. In this work Expanded Bed Adsorption was used to recover and purify whey proteins from coalho cheese manufacture using Streamline DEAE and Streamline SP both ionic resins as well as a hydrophobic resin Streamline Phenyl. A column of 2.6 cm inner diameter with 30 cm in height was coupled to a peristaltic pump. Hydrodynamics study was carried out with the three resins using Tris-HCl buffer in concentration of 30, 50 and 70 mM, with pH ranging from 7.0 to 8.0. In this case, assays of the expansion degree as well as Residence Time Distribution (RTD) were carried out. For the recovery and purification steps, a whey sample of 200 mL, was submitted to a column with 25mL of resin previously equilibrated with Tris/HCl (50 mM, pH 7.0) using a expanded bed. After washing, elution was carried out according the technique used. For ionic adsorption elution was carried out using 100 mL of Tris/HCl (50 mM, pH 7.0 in 1M NaCl). For Hydrophobyc interaction elution was carried out using Tris/HCl (50 mM, pH 7.0). Adsorption runs were carried out using the three resins as well as theirs combination. Results showed that for hydrodynamics studies a linear fit was observed for the three resins with a correlation coefficient (R2) about 0.9. In this case, Streamline Phenyl showed highest expansion degree reaching an expansion degree (H0/H) of 2.2. Bed porosity was of 0.7 when both resins Streamline DEAE and Streamline SP were used with StremLine Phenyl showing the highest bed porosity about 0.75. The number of theorical plates were 109, 41.5 and 17.8 and the axial dipersion coefficient (Daxial) were 0.5, 1.4 and 3.7 x 10-6 m2/s, for Streamline DEAE, Streamline SP and Streamline Phenyl, respectively. Whey proteins were adsorved fastly for the three resins with equilibrium reached in 10 minutes. Breakthrough curves showed that most of proteins stays in flowthrough as well as washing steps with 84, 77 and 96%, for Streamline DEAE, Streamline SP and Streamline Phenyl, respectively. It was observed protein peaks during elution for the three resins used. According to these peaks were identified 6 protein bands that could probably be albumin (69 KDa), lactoferrin (76 KDa), lactoperoxidase (89 KDa), β-lactoglobulin (18,3 KDa) e α-lactoalbumin (14 KDa), as well as the dimer of beta-lactoglobulin. The combined system compound for the elution of Streamline DEAE applied to the Streamline SP showed the best purification of whey proteins, mainly of the α-lactoalbumina

Prática Investigativa: experimentando o mundo da microbiologia

Dentro de uma imagem construtivista a experimentação apresenta características peculiares, como o uso de conhecimentos prévios, dialogo, reflexão, problematização, interdisciplinaridade, e relações ao cotidiano, apresentando-se como uma atividade de investigação, em que o aluno deve refletir, discutir, explicar e relatar, caracterizando assim uma investigação científica Este trabalho tem como objetivo promover aprendizagem significativa do conteúdo de microbiologia, considerado um conteúdo abstrato, através de atividades empíricas se utilizando do método por investigação, desmistificando a informação de que microrganismos são apenas agentes patogênicos ao focar ecologia e importância econômica de alguns desses seres, e sensibilizando quanto à importância da higienização correta dos alimentos ingeridos crus. Abordagem foi realizada no 2º ano do ensino médio em uma escola pública, conveniada ao PIBID/UFRN/Biologia. Concretizada pela aplicação de duas atividades experimentais baseadas na problematização: “Agora eu vi, realmente existem!” e “Comer, comer para poder crescer”. Os experimentos foram realizados em aulas diferentes e caracterizam-se em sensibilização da higienização de alimentos consumidos crus, e análise da função e importância econômica de alguns microrganismos. A exposição do estudante a um problema em que ele pode vivenciar no se dia-a-dia o encoraja a envolver-se no seu próprio processo de aprendizagem, além de orientá-lo a aplicar o conhecimento adquirido em situações práticas, desenvolvendo desta forma habilidades especificas que possibilitem a continuidade de sua educação. Concluímos então que utilização de atividades experimentais realizadas pelo método de investigação gera aprendizagem de procedimentos e atitudes, além da aprendizagem de conceitos/conteúdos.

Estádios larvais e ocorrência saxonal de imaturos de Psaroniocompsa incrustata (Lutz,1910)(Diptera:Smimuliidae) no Rio Pium, município de Nísia Floesta, RN

The larval instars, seasonal occurrence and environmental factors influence on Psaroniocompsa incrustata (Lutz, 1910) (Diptera: Simuliidae) immature were studied according to its physical and chemical aspects of breeding water. Four collects were made at vegetal substrate from margin, middle and floating on the Pium river, city of Nísia Floresta, state of Rio Grande do Norte, Brazil at dry and wet season. Some of larval characters were used to determinate the larval instars number like lateral length of cephalic capsulae, antennae and the distance among cephalic apodema, as well as pH, water temperature, width, depth, stream velocity, discharge and pluviometric precipitation were used for physical factors. Seven larval instars were determined for this P. incrustata community being the lateral length of cephalic capsulae as the best structure with this meaning propose. The seasonality immature abundance of this species were found in dry season and a positive correlation with pH, stream velocity and precipitation

Abundância das formas imaturas de Psaroniocompsa incrustata ( Lutz, 1910) (Diptera: Simuliidae) em um criadouro natural no rio Pium/RN, e sua fauna associada

The species psaroniocompsa incrustata (Lutz, 1910) was studied in relation to its abundance in different and seasonal periods, the physico-chemical of the breending ground and the fauna predation added to the immature of the species. The study was developed during eight months, from April to July, 2005 (rainy season) and from October, 2005 to January, 2006 (drought season), in one natural breending ground situated in the Pium river, that is part of the hydrographical basin of the Pirangi river in Rio Grande do Norte. The immature of Simuliidae were collected manually in vegetal substrate. At the same place, it was made one sampling of the associated fauna using Suber collectors and the measurement of the environment variants. It was also made one analysis of the stomach content of possible enemies of the simulídeos, to observe the predation of the associated fauna. It was collected 7.713 samples, all from de species P. Incrustata, it was observed a bigger abundance in the drought season, and the entomologic fauna associated totalizing 20.1314 species, distributed in the kinds: Diptera, Ephemeroptera, Odonata, Trichoptera, e Hemiptera, with a bigger representativity of Dipteros. The analysis of the stomach content of the species from the families Libellulidae and Hydropsychidae showed the presence of the simulídeos in only 4% of the material analysed, therefore it was not confirmed the presence of one efficient biological control of the simulídeos in this breending ground

Metagenômica: busca de novos genes envolvidos com a biodegradação de hidrocarbonetos

Industrial activities, oil spills and its derivatives, as well as the incomplete combustion of fossil fuels have caused a great accumulation of hydrocarbons in the environment. The number of microorganisms on the planet is estimated at 1030 and prokaryotes the most abundant. They colonized diverse environments for thousands of years, including those considered extreme and represent an untapped source of metabolic and genetic diversity with a large biotechnological potential. It is also known that certain microorganisms have the enzymatic capacity to degrade petroleum hydrocarbons and, in many ecosystems, there is an indigenous community capable of performing this function. The metagenomic has revolutionized the microbiology allowing access uncultured microbial communities, being a powerful tool for elucidation of their ecological functions and metabolic profiles, as well as for identification of new biomolecules. Thus, this study applied metagenomic approaches not only for functional selection of genes involved in biodegradation and emulsification processes of the petroleum-derived hydrocarbons, but also to describe the taxonomic and metabolic composition of two metagenomes from aquatic microbiome. We analyzed 123.116 (365 ± 118 bp) and 127.563 sequences (352 ± 120 bp) of marine and estuarine metagenomes, respectively. Eight clones were found, four involved in the petroleum biodegradation and four were able to emulsify kerosene indicating their abilities in biosurfactants synthesis. Therefore, the metagenomic analyses performed were efficient not only in the search of bioproducts of biotechnological interest and in the analysis of the functional and taxonomic profile of the metagenomes studied as well

Avaliação in vitro da atividade antimicrobiana de diferentes soluções a base de hidróxido de cálcio

The science of Dentistry wishes obtains the ideal solution for the dental plaque chemical control. This research evaluated antimicrobial action capacity in calcium hydroxide and tergentol various solutions starting for the CHD 20, a root canals irrigating solution with a reason of 80% calcium hydroxide saturated solution and 20% tergentol detergent with the aim of evaluate this drug mouth rinse indication with prevention or combat objective for dental caries and periodontal diseases. Antibiogram disks and biofilm tests were accomplished for the microorganisms: Streptococcus mutans, Streptococcus sanguis, Streptococcus sobrinus and Lactobacillus casei. Different reasons of detergent for the calcium hydroxide saturated solution, tergentol and distillated water solution, 0,12% clorhexydine digluconate solution was positive control and distillated water was negative control. The results showed better performance of clorhexydine in relation to calcium hydroxide directing to not accept this (CHD20) as mouth rinse solution

Avaliação das condições higiênico-sanitárias da produção de refeições à base de carne da alimentação escolar no município de Natal-RN

The National School Nutrition Program is the oldest program in the country directed at food and nutrition safety. Its aims are to offer nutritional food as a supplement to students of public and philanthropic schools. Studying school nutrition transcends the investigation as a purely social program, given that it reaches the fields of public health, nutrition and food, using a wide variety of approaches. Thus, it is characterized by a multidisciplinary study, where the disciplines work side by side in distinct aspects of a single problem. Aim: This study aims to assess hygiene practices during the preparation of meat-based meals in public schools in the city of Natal, Brazil. Methods: A list was applied at 27 schools to identify the procedures of good food preparation practices. In addition, cooking and meal distribution temperature were measured and a microbiological analysis of the final preparation and of the water used in preparing it was performed. For microbiological analyses of the food, we analyzed coliforms at 45°C, coliforms at 35°C and Enterococcus, and for the water, we analyzed thermotolerant coliforms and total coliforms, using the methods recommended by APHA, 1995. Results: Most of the schools did not meet the required standards in all the variables related to good food preparation practices, except for the time spent preparing the meat, in which 89% were within the norm. Cooking temperature of the meals was within the standard; however, the temperature at distribution and the time spent dispensing the meals were inadequate. Of the 27 schools, 22 (81.5%) showed the presence of coliforms at 35° C in at least one meal sample and 18 (66.7%) had values above the recommended limit for coliforms at 45°C. The presence of E. coli was identified in 6.1% of the samples analyzed. The presence of Enterococcus was not found at any of the schools. With respect to the water, the North district of the city was the only one that did not meet the standards for the two indicators evaluated. The contamination found was not associated with the hygiene or food storage problems observed. Conclusions: The results show that the hygiene-sanitary conditions of meat-based public school meals were unsatisfactory, demonstrating the need for improvements in the production process to preserve the health of the student population. Multidisciplinarity: Researchers from the areas of food microbiology, nutrition, public health and statistics took part in this study, a decisive factor for characterizing the research as multidisciplinary

Avaliação das condições higiênico-sanitárias de manipuladores de alimentos e utensílios de mesa de escolas públicas municipais de Natal, RN

In Brazil school food is constitutionally guaranteed to public school students at the preschool and elementary level. This food must be nutritious, hygienic and sanitary. The aim of the present study was to assess the hygienic/sanitary conditions of food and table utensil handlers in municipal public schools in Natal, Brazil. In total, 27 public schools were assessed, using a checklist and microbiological analysis of the hands and table utensils. For the microbiological analyses of the hands, coliforms were analyzed at 45ºC and for the utensils aerobic mesophilic bacteria, using methods recognized by AOAC, 2002 and APHA, 1992, respectively. Most of the schools studied did not exhibit good food and utensil handling practice procedures in any of the variables analyzed. It was shown that 74.1% of the handlers received no periodic training, 51.9% did not undergo annual health examinations and 100% did not practice proper hand hygiene, which reflected significantly (p < 0.05) in hand contamination, where fecal coliforms were detected on 55.6% of the hands analyzed. With respect to the utensils, it was found that 100% of the schools studied did not follow correct hygiene practices and most were classified as very bad ; that is, aerobic mesophilic bacteria values above the limits established by PAHO (Pan American Health Organization), with schools in the north and south districts recording the highest percentages. The results show that the hygienic-sanitary conditions of the food and utensil handlers in the schools studied were inadequate, demonstrating the need for implanting good handling practices aimed at protecting the health of children that take part in the program and offering safer foods. Researchers from the areas of food microbiology, nutrition, public health and statistics participated in this study, a decisive factor for characterizing it as multidisciplinary

Caracterização fenotípica e genotípica de Staphylococcus aureus resistentes à meticilina isolados na cidade do Natal/RN

Staphylococcus aureus resistente à meticilina (MRSA) é um dos principais agentes de infecções associadas a serviços de saúde em todo o mundo. No Brasil, há a predominância de um clone de MRSA multirresistente denominando clone epidêmico brasileiro (CEB). Entretanto, novos clones nãomultirresistentes com alta virulência têm sido descritos em infecções comunitárias e hospitalares. O objetivo desse estudo foi realizar a caracterização fenotípica e genotípica de cepas de MRSA isoladas na cidade do Natal/RN. Inicialmente avaliamos 60 amostras de S. aureus quanto a resistência à meticilina através de diferentes técnicas fenotípicas, utilizando a detecção do gene mecA por PCR como padrão. O antibiograma de todas as cepas foi realizado utilizando 12 antimicrobianos conforme descrito pelo CLSI. As cepas de MRSA foram caracterizadas geneticamente através da tipagem do cassete cromossômico estafilocócico mec (SCCmec) e da eletroforese em campo elétrico alternado (PFGE). Dos 60 S. aureus estudados, 45 foram resistentes à meticilina. Observamos que para algumas cepas de MRSA os testes de triagem em ágar com 6μg/mL de oxacilina e difusão em meio sólido com oxacilina-1μg apresentaram dificuldades na sua interpretação. No entanto, todas as 45 amostras de MRSA, foram facilmente detectadas pelos testes com o disco de cefoxitina-30μg e pesquisa da PBP2a. A análise molecular das cepas de MRSA mostrou 8 padrões distintos de PFGE (A-H), com predominância do padrão A (73%), relacionado ao CEB. Estas carreavam o SCCmec tipo IIIA, e apresentaram uma considerável variedade de subtipos (A1-A16). Cinco cepas de MRSA portando SCCmec IV também foram xiv identificadas, três delas relacionadas geneticamente ao clone USA800 (Padrão B). Destas cinco, três (2 padrão F e 1 padrão B) foram altamente susceptíveis as drogas testadas, entretanto, dois outros isolados, padrão B, apresentaram multirresistência. As amostras restantes pertenciam a padrões de PFGE distintos dos clones internacionais predominantes em nosso continente. Para realização deste projeto de pesquisa, a metodologia exigiu a interação com pesquisadores de áreas como: infectologia, microbiologia e biologia molecular. Portanto, esta dissertação apresentou um caráter de multidisciplinaridade e transdiciplinaridade no seu desenvolvimento

Efeito do ácido lático sobre as características microbiológicas, físico-químicas e sensoriais na carne do sol

The dried beef is a food traditionally eaten by Northeastern and has an extensive trade in the city of Natal-RN. It is usually produced in an empirical manner, without any standardization in production. Characterized as partially dehydrated meat product, so that the activity of water present is not sufficient to prevent microbial growth, degradation or the production of microbial toxins. The guarantee that the market dried beef is to provide a quality product hygienic, microbiological, physicochemical and sensory stable and adequate for the safety and consumer satisfaction, which has been increasingly attracted to food with natural preservatives. Thus, the meat industries are replacing the current seasonings and natural preservatives for similar, with it without affecting the shelf life of products. Lactic acid has been used to meet these requirements. In this sense, this study aimed to evaluate the effect of lactic acid on the physico-chemical, microbiological and sensory, besides knowing the consumer profile of dried meat of the City of Natal / RN. The results demonstrated that the use of lactic acid in concentrations of 1% and 2% during the processing of dried meat, had statistically significant effect (p < 0.05) on the physico-chemical (pH and water activity) and consequently reduced the microbial count does not alter the taste of the new product developed. Regarding the results on the consumer profile, it was found that the majority of respondents (71.75%) did not observe the presence of the stamp of the Federal Inspection Service (SIF) to buy this meat food that 81.55% of consumers check the hygiene conditions of the site and handlers, however, a large proportion of respondents not concerned with the guarantee of origin of typical regional products featuring a hazard to food safety for consumers of the city of Natal-RN

Avaliação de catalisadores a base de carbeto e nitreto de molibdênio na obtenção de lactitol via hidrogenação da lactose

Seeking a greater appreciation of cheese whey was developed to process the hydrogenation of lactose for the production of lactitol, a polyol with high added value, using the catalyst Ni / activated carbon (15% and 20% nickel), the nitride Mo2N, the bimetallic carbide Ni-Mo/ activated carbon and carbide Mo2C. After synthesis, the prepared catalysts were analyzed by MEV, XRD, laser granulometry and B.E.T. The reactor used in catalytic hydrogenation of lactose was the type of bed mud with a pressure (68 atm), temperature (120 oC) and stirring speed (500 rpm) remained constant during the experiments. The system operated in batch mode for the solid and liquid and semi-continuous to gas. Besides the nature of the catalyst, we studied the influence of pH of reaction medium for Mo2C carbide as well as evaluating the character of the protein inhibitor and chloride ions on the activity of catalysts Ni (20%)/Activated Carbon and bimetallic carbide Ni-Mo/Activated Carbon. The decrease in protein levels was performed by coagulation with chitosan and adsorption of chloride ions was performed by ion exchange resins. In the process of protein adsorption and chloride ions, the maximum percentage extracted was about 74% and 79% respectively. The micrographs of the powders of Mo2C and Mo2N presented in the form of homogeneous clusters, whereas for the catalysts supported on activated carbon, microporous structure proved impregnated with small particles indicating the presence of metal. The results showed high conversion of lactose to lactitol 90% for the catalyst Ni (20%)/Activated Carbon at pH 6 and 46% for the carbide Mo2C pH 8 (after addition of NH4OH) using the commercial lactose. Monitoring the evolution of the constituents present in the reaction medium was made by liquid chromatography. A kinetic model of heterogeneous Langmuir Hinshelwood type was developed which showed that the estimated constants based catalysts promoted carbide and nitride with a certain speed the adsorption, desorption and production of lactitol