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Simbiose feij?o-caupi e riz?bio: diversidade de bact?rias associadas aos n?dulos / Symbiosis cowpea and rhizobia: bacteria diversity associated to root nodulesLEITE, Jakson 27 February 2015 (has links)
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Previous issue date: 2015-02-27 / CAPES / Cowpea [Vigna unguiculata (L.) Walp] is an important crop in northeastern Brazil with strategic advantages for production in semi-arid region, such its drought tolerance and good performance in low fertility soils. In addition, the nitrogen (N) fixed in symbiosis with rhizobia eliminates the demand for N fertilizers, with economic, social and environmental benefits. Little is known about the genetic diversity of bacteria associated to cowpea nodules in Brazilian semi-arid. The aim of the study was to characterize the bacterial diversity of Brazilian semi-arid soils associated with nodules of different cowpea cultivars by dependent and independent bacterial cultivation strategy. Initially a collection of 86 bacteria cowpea nodules isolated from semiarid soils was genetically characterized by partial 16S rRNA gene sequencing and symbiotic genes nifH and nodC. The sequences were compared with the NCBI database to identify isolates and phylogenetic relationships were built. In another study, we applied the independent cultivation method to evaluate bacterial communities associated with the nodules of two cowpea cultivars (BRS and BRS Acau? Pujante), in Ultisol with no history of cowpea cultivation. Nodules (N) were collected 35 days after germination, and soil samples (BS) from 0-20 cm deeper. DNA was extracted for analysis of bacterial communities with 454 pyrosequencing of the 16S ribosomal gene rRNA. The analysis of the diversity of the bacterial collection of the nodules 54 of the 86 isolates were Bradyrhizobium. Other (32) belong to Rhizobium (13) and Microvirga (1), Alfaproteobact?ria class; Burkholderia (8), and Ralstonia (1), Betaproteobacteria class; Acinetobacter (1), Cronobacter (3), Enterobacter (1), and Pantoea (1), Gamaproteobact?ria; and Leifsonia (3), phylum Actinobacteria. As Bradyrhizobium predominated, analyzes were performed with the almost full 16S rRNA, nifH and nodC and isolates were distributed in 5 lines: 16S rRNA type I (44 isolates), type II (6), Type III (1), Type IV ( 2) and type IV (1). Phylogenetic analysis of the 16S rRNA gene grouped the Type I strain in the large group Bradyrhizobium japonicum and close to the type strain of Bradyrhizobium yuanmingense. The analyses of the nifH and nodC gene separated the isolates in 5 symbiotic lines (I, II, III, IV and IV) and were congruent among them, which supports the theory of monophyletic in origin symbiotic gene Bradyhrizobium. The symbiotic lineages I and II are nearby and correspond to all isolates with 16S rRNA type I, being the dominant group associated with nodules. The partial 16S rRNA gene sequencing of bacterial communities showed high diversity in the three environments (BS, RS and N). The communities associated with the nodes were significantly different (p> 0.01) from the surrounding nodules (LS and RS). Phyla Actinobacteria, Bacteriodetes, Proteobacteria were plentiful for BS and RS. In nodes, the Proteobacteria and Bacteriodetes phyla predominated, Gammaproteobacteria being (58.8%) and Alphaproteobacteria (37.4%) in the phylum Proteobacteria and dominant Flavobacteriia (84.8%) and Sphingobacteriia (10.9%) in the phylum Bacteriodetes. For gender, Chryseobacterium, Entreobacter and Bradyrhizobium dominate in all nodes samples where Chryseobacterium prevailed in BRS Acau? and Enterobacter in BRS Pujante. / O feij?o-caupi [Vigna unguiculata (L.) Walp] ? uma das principais culturas no Nordeste do Brasil com vantagens estrat?gicas para produ??o no semi?rido, como toler?ncia a seca e bom desempenho em solos de baixa fertilidade. Al?m disso, fixa N em simbiose com riz?bios eliminando a demanda de fertilizantes nitrogenados, com benef?cios econ?micos, sociais e ambientais. Pouco se sabe sobre a diversidade gen?tica de bact?rias associadas aos n?dulos de feij?o-caupi no semi?rido. O objetivo do estudo foi caracterizar a diversidade de bact?rias de solos do semi?rido brasileiro associadas aos n?dulos de diferentes cultivares de feij?o-caupi com arbordagem que depende e independe de cultivo das bact?rias. Inicialmente uma cole??o de 86 bact?rias de n?dulos de feij?o-caupi isoladas de solos do semi?rido foi caracterizada geneticamente pelo sequenciamento parcial do gene 16S rRNA e dos genes simbi?ticos nifH e nodC. As sequ?ncias foram comparadas com as do banco de dados do NCBI para identificar os isolados e as rela??es filogen?ticas dos mesmos com as de esp?cies conhecidas. Em outro estudo, aplicou-se o m?todo independente de cultivo para avaliar comunidades de bact?rias associadas aos n?dulos de dois cultivares de feij?o-caupi (BRS Pujante e BRS Acau?), em Argissolo Amarelo sem hist?rico de uso com a lavoura. Os n?dulos (N) foram coletados 35 dias ap?s a germina??o e a amostragem do solo (BS) de 0-20 cm. O DNA das amostras foi extra?do para an?lises das comunidades bacterianas com 454 pirosequenciamento do gene ribossomal 16S rRNA. Na an?lise da diversidade da cole??o de n?dulos 54 dos 86 dos isolados foram de Bradyrhizobium. Os demais (32) pertencem aos g?neros Rhizobium (13) e Microvirga (1), classe Alfaproteobact?ria; Burkholderia (8) e Ralstonia (1), classe Betaproteobact?ria; Acinetobacter (1), Cronobacter (3), Enterobacter (1) e Pantoea (1), Gamaproteobact?ria; e Leifsonia (3), filo Actinobact?ria. Como Bradyrhizobium predominou, foram feitas an?lises com os genes 16S rRNA, nifH e nodC e os isolados distribu?ram-se em 5 linhagens: 16S rRNA tipo I (44 isolados), tipo II (6), tipo III (1), tipo IV (2) e tipo IV (1). A an?lise filogen?tica do gene 16S rRNA agrupou a linhagem tipo I no grande grupo Bradyrhizobium japonicum e pr?ximo da estirpe tipo de Bradyrhizobium yuanmingense. A an?lise dos genes nifH e nodC separou os isolados em 5 linhagens simbi?ticas (I, II, III, IV e IV) e as ?rvores foram congruentes, o que suporta a teoria da origem monofil?tica de genes simbi?ticos em Bradyhrizobium. As linhagens simbi?ticas I e II s?o pr?ximas e correspondem a todos os isolados com 16S rRNA tipo I, sendo o grupo dominante associado aos nodulos. O sequenciamento parcial do gene 16S rRNA das comunidades bacterianas mostrou alta diversidade nos tr?s ambientes (BS, RS e N). As comunidades associadas aos n?dulos foram significativamente diferentes (p> 0,01) das que cercam os n?dulos (LS e RS). Os filos Actinobacteria, Bacteriodetes, Proteobacteria foram abundantes para BS e RS. Em n?dulos, os filos Proteobacteria e Bacteriodetes predominaram, sendo Gammaproteobacteria (58,8%) e Alphaproteobacteria (37,4%) dominantes no filo Proteobacteria e Flavobacteriia (84,8%) e Sphingobacteriia (10,9%) no filo Bacteriodetes. Para g?nero, Chryseobacterium, Entreobacter e Bradyrhizobium dominam em todas as amostras de n?dulos, onde Chryseobacterium predominou em BRS Acau? e Enterobacter em BRS Pujante.
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Estudo de diversidade gen?tica e produ??o de enzimas celulol?ticas em bact?rias associadas ao trato digestivo de invertebrados sapr?fagos / Study of genetic diversity and production of cellulolytic enzymes in bacterias associated to the intestinal tract of saprophages invertebratesCORREIA, Dayana da Silva 26 March 2014 (has links)
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Previous issue date: 2014-03-26 / CAPES / CNPq / The symbiosis between soil invertebrates and micro"organisms is a major ally in promoting the decomposition of plant residues in the soil. The micro"organisms in turn, have an immense genetic diversity and play crucial roles in maintaining ecosystems. One of these functions is the production of extracellular enzymes that assist the mineralization of organic matter. The possibility of developing new biotechnological processes based on the exploration of microbial diversity is immense, due to the great variability that exists between biological systems and it can be optimized to improve the agricultural production systems in a sustainable manner. The objective of this work was to study the profile of the bacterial community and cellulolytic potential of bacteria isolated from three different species of invertebrates saprophages. The experiments were performed at the Experimental Station of Embrapa Agrobiology, Serop?dica, Rio de Janeiro State. Millipede, of the Trigoniulus corallinus species, were collected in piles of plant compounds from local experimental field sites, which were subsequently incubated for 60 days under six different diets. Bacterial diversity in the intestinal tract of invertebrates was analyzed by PCR"DGGE of 16S rDNA gene amplification by PCR electrophoresis in denaturing gradient gel (DGGE); two domains were used, Bacteria and Actinobacteria. Some bands of the DGGE gel were extracted and sequenced. To assess the potential for production of cellulases in response to the presence of carboxy methyl cellulose (CMC) of isolates, the technique Congo red stain was used and the values were expressed as means (Ie) enzymatic index. From the highest values of (Ie) twenty" three bacteria were selected for the analysis of 16S rDNA. After the phylogenetic identification, the cellulolytic potential was rated, through cellulolytic activity of endoglucanase (CMCase), and endo" and exoglucanases (FPase) tests. To determine the molecular weight and activity of the enzymes polyacrylamide gels (SDS"PAGE) and zymography were performed. The results obtained in the technique of DGGE, the profiles of DGGE bands, showed that the intestinal microbiota of the invertebrates has distinct bacterial groups. It is possible to infer that, despite the communities having similar abundance, such as in the Trigoniulus corallinus and Cubaris murine species, the groups that make up this abundance were different among the invertebrate?s species. From the clones of the incised bands, three phyla members, Proteobacteria, Firmicutes and Bacteroidetes, were sequenced. Through phylogenetic analysis, it was possible to identify the 23 species of bacteria. Presenting two distinct Actinomycetes and Firmicutes phylum, the largest genus identified was Streptomyces, followed by an isolated Bacillus, Paenibacillus, and Staphylococcus. The intestinal tract of the three species of saprophages invertebrates showed to be an adequate environment for prospection of bacteria with cellulolytic efficiency, with high potential for future biotechnological studies. / A simbiose entre invertebrados do solo e microrganismos ? um grande aliado no auxilio da decomposi??o de res?duos vegetais presentes no solo. Os microrganismos por sua vez, apresentam uma imensa diversidade gen?tica e desempenham fun??es cruciais na manuten??o dos ecossistemas, uma dessas fun??es ? a produ??o de enzimas extracelulares que auxiliam na mineraliza??o da mat?ria org?nica. A possibilidade de desenvolver novos processos biotecnol?gicos com base na prospec??o da diversidade microbiana ? imensa, em decorr?ncia da grande variabilidade que existe entre os sistemas biol?gicos e que podem ser aperfei?oados para melhorar os sistemas de produ??o agr?colas de forma sustent?vel. O objetivo deste trabalho foi estudar o perfil da comunidade bacteriana e potencial celulol?tico de bact?rias isoladas de tr?s diferentes esp?cies de invertebrados sapr?fagos. Os experimentos foram montados no Campo Experimental da Embrapa Agrobiologia, Serop?dica, Rio de Janeiro. Gong?los, da esp?cie Trigoniulus corallinus, foram coletados em pilhas de compostos vegetais presentes em torno do campo experiemental, que posteriormente foram incubados durante 60 dias, sob seis diferentes dietas. A diversidade bacteriana do trato intestinal dos invertebrados foi analisada atrav?s da t?cnica de PCR"DGGE por amplifica??o do gene 16S rDNA PCR por eletroforese em gel com gradiente desnaturante (DGGE); foram utilizados dois dom?nios Bacteria e Actinobact?ria. Algumas bandas do gel de DGGE foram extra?das e sequenciadas. Para avaliar o potencial quanto ? produ??o de celulases em resposta ? presen?a de carboxi"metil"celulose (CMC) das bact?rias isoladas, foi utilizada a t?cnica de colora??o vermelho Congo, e os valores foram expressos atrav?s de (Ie) ?ndice enzim?tico. A partir dos maiores valores de (Ie), foram selecionadas vinte e tr?s bact?rias para a an?lise de sequenciamento do gene 16S rDNA. Ap?s a identifica??o filogen?tica, foi avaliado o potencial celulol?tico, atrav?s de testes de atividade celulol?tica de endoglucanases (CMCase) e endo e exoglucanases (FPase). Para determinar a massa molecular e atividade das enzimas foram realizados g?is de poliacrilamida (SDS"PAGE) e zimograma. Os resultados obtidos na t?cnica de DGGE, os perfis de bandas de DGGE mostrou que a microbiota intestinal dos invertebrados, det?m grupos bacterianos distintos. Pode"se inferir neste ponto, que apesar das comunidades possu?rem abund?ncia similar, como as esp?cies de Trigoniulus corallinus e Cubaris murina, os grupos que comp?em esta abund?ncia foram diferentes entre as esp?cies de invertebrados. A partir dos clones de bandas incisadas, foram sequ?nciados membros de tr?s filos, Proteobacteria, Firmicutes e Bacteroidetes. Atrav?s da an?lise filogen?tica, foi poss?vel identificar as 23 esp?cies de bact?rias. Apresentando dois filos distintos Actinomicetos e Firmicutes, o maior g?nero identificado foi Streptomyces, seguido de um isolado para Bacillus, Paenibacillus e Staphylococcus. O trato intestinal das tr?s esp?cies de invertebrados sapr?fagos revelou ser um ambiente h?bil ? prospec??o de bact?rias com efici?ncia celulol?tica, com alto potencial para futuros estudos biotecnol?gico.
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Re-Evaluierung, methodische Optimierung und weitergehende Charakterisierung der Empfindlichkeitstestung von Mycobacterium tuberculosis mit dem BacT/Alert 3D (bioMérieux)Knigge, Anna Sophie 07 April 2014 (has links) (PDF)
Es erfolgte die Re-Evaluierung der Empfindlichkeitstestung von Tuberkuloseerregern mit dem BacT/Alert-3D-System (bioMérieux) unter besonderer Berücksichtigung des Materialwechsels der Kulturflasche von Glas auf Plastik. Dazu wurden insgesamt 61 vergleichende MHK-Bestimmungen mit diesen beiden Flaschentypen durchgeführt, wobei sechs Antituberkulotika (INH, RMP, EMB, SM, PTH und MOX) sowie zwölf Mykobakterienstämme (davon neun Mtb.) untersucht wurden. Dabei findet sich kein Unterschied in den MHK-Werten zwischen Glas- und Plastikflaschen. Die Plastikflaschen sind folglich ebenso wie die Glasflaschen zur Empfindlichkeitstestung von Tuberkuloseerregern mit dem BacT/Alert-3D-System geeignet. Bei der bisherigen Methode wurde bei der PZA-Testung auf die Verwendung der Kontrollflasche zur Festlegung der Untersuchungszeit verzichtet, weil der erniedrigte pH-Wert ein unverhältnismäßig langsames oder gar fehlendes Wachstum in dieser Flasche bewirkt. Durch Optimierung von pH-Wert (pH 5,9) und PZA-Testkonzentration (200 mg/l) wurde erreicht, dass die PZA-Testung nach der gleichen Methode wie auch bei den anderen Antituberkulotika praktiziert, durchgeführt werden kann. Im weiteren wurde untersucht, wie hoch der Anteil resistenter Mutanten in Mischkulturen sein muss, um erkannt zu werden. Dazu wurden dem sensiblen Stamm H37Rv jeweils isogene Mutanten mit Monoresistenzen gegen INH, RMP oder SM bzw. EMB- und PZA-resistente Stämme in verschiedenen Anteilen zugesetzt. Es zeigte sich, dass ein Anteil von 1% resistenter Stämme noch nicht sicher detektiert wird. / The purpose of this paper is to optimize and reevaluate the methods of susceptibility testing of M.tuberculosis with the BacT/Alert 3D System (bioMérieux). The key aspect was the comparison between culture bottles from glass between those made out of plastic material. Therefore 61 comparative MIC-tests were carried out, with six antituberculous drugs (INH, RMP; EMB, SM, PTH and MOX) and twelve mycobacterial strains (nine Mtb.) in order to compare the MIC in the two different bottle types. The MIC of 40 comparative tests between plastic culture bottles were identical to those in glass material. Only 18 test results deviated between the two bottle types. In each of those tests the discrepancy was only one degree of dilution, which is considered as not relevant. Resistant strains were found in three tests, with no difference between glass and plastic bottles. The deviant twelve results of Mtb. strains show a six times higher MIC-value in plastic bottles and a six times lower MIC in plastic bottles. In the case of the substance INH all four discrepant results had a higher MIC in the plastic bottle. Since these results were known by the Institut für Medizinische Mikrobiologie und Infektionsepidemiologie of the University Leipzig, it was consequently used with good results in the laboratory routine, as well as in external quality control (INSTAND-Ringversuche 2009 to 2011).
The second topic of this study was to optimize the current method of susceptibility testing of Mtb. concerning pyrazinamide (PZA). In the current method the low pH of the dilution (5.5) with the resulting weak growth of the strains forced the laboratory assistant to abandon the 1% control bottle as endpoint of measurement. The new and optimized pH of 5.9 and a concentration of PZA of 200 mg/l allows the susceptibility testing of PZA with the same method as practiced for the other antituberculous drugs.
Yet another focus of this study was the sensitivity of the BacT/Alert 3D System to detect heteroresistant clones in the mycobacterial broth. Resistant clones and fully susceptible Mtb. strain (H37Rv) were mixed in different percentages and susceptibility testing was performed. It could be shown, that a secure detection of resistant clones is not possible at a percentage 1% of resistant clones in the culture.
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Detec??o de bact?rias periodontopatog?nicas cultiv?veis e n?o cultiv?veis em placas ateromatosasAquino, Ana Rafaela Luz de 12 January 2009 (has links)
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Previous issue date: 2009-01-12 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Periodontal infections consist of a group of inflammatory conditions caused by microorganisms that colonize the tooth surface through the formation of dental biofilm. Chronic infections such as periodontitis have been associated to the development and progression of atherosclerosis. AIM: Detect cultivatable and non-cultivatable periodontopathogenic bacteria in atheromatous plaques; search for factors associated to the presence of these bacteria in the atheromatous plaques and characterize the presence of cultivatable and non-cultivatable bacteria in these plaques. METHODOLOGY: A cross-sectional study was performed with a sample of 30 patients diagnosed with atherosclerosis in the carotid, coronary or femoral arteries and surgically treated with angioplasty and stent implant, bypass or endarterectomy. The plaques were collected during surgery and analyzed using the PCR molecular technique for the presence of the DNA of the cultivatable bacteria Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Treponema denticola and of the non-cultivatable Synergistes phylotypes. The patients were examined in the infirmary, after the surgery, where they also responded to a questionnaire aimed at determining factors associated to the presence of periodontopathogenic bacteria in the atheromatous plaques. RESULTS: All patients with tooth (66,7%) possessed disease periodontal, being 95% severe and 65% widespread. No periodontopathogenic bacteria were found in the atheromatous plaques. However, four samples (13.3%) were positive for the presence of bacteria. Of these, three participants were dentate, being two carriers of widespread severe chronic periodontite and one of located severe chronic periodontitis. None of them told the accomplishment of procedures associated to possible bacteremia episodes, as treatment endodontic, extraction the last six months or some procedure surgical dental. CONCLUSION: The periodontopathogenic bacteria studied were not found in the atheromatous plaques, making it impossible to establish the prevalence of these pathogens or the factors associated to their presence in plaques, the detection of positive samples for bacteria suggests that other periodontal and non-periodontal pathogens be studied in an attempt at discovering the association or not between periodontal disease and/or others infections and atherosclerosis, from the presence of these bacteria in atheromas / As infec??es periodontais compreendem um grupo de condi??es inflamat?rias, causadas por microrganismos que colonizam a superf?cie dent?ria, atrav?s da forma??o do biofilme dent?rio. Atualmente, infec??es cr?nicas como as periodontais t?m sido associadas ao desenvolvimento e progress?o da aterosclerose. OBJETIVOS: Detectar bact?rias periodontopatog?nicas cultiv?veis e n?o cultiv?veis em placas ateromatosas; buscar fatores associados ? presen?a destas bact?rias nas placas ateromatosas e caracterizar a presen?a de bact?rias cultiv?veis e n?o cultiv?veis em placas ateromatosas. METODOLOGIA: Foi realizado um estudo seccional, utilizando uma amostra de 30 pacientes que apresentaram o diagn?stico de aterosclerose nas art?rias car?tidas, coronarianas ou femorais, e foram tratados cirurgicamente atrav?s da realiza??o dos procedimentos de angioplastia com implante de stent, bypasse ou endartarectomia. As placas foram coletadas durante as cirurgias realizadas e analisadas atrav?s da t?cnica molecular de PCR para a presen?a de DNA das bact?rias periodontais cultiv?veis Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis e Treponema denticola e o filotipo n?o-cultiv?vel Synergistes species. Os pacientes foram examinados no leito da enfermaria, ap?s as cirurgias, onde tamb?m responderam a um question?rio cujo objetivo foi buscar fatores associados ? presen?a de bact?rias periodontopatog?nicas nas placas ateromatosas. RESULTADOS: Todos os pacientes dentados (66,7%) possu?am doen?a periodontal, sendo 95% severa e 65% generalizada.Nenhuma bact?ria periodontopatog?nica pesquisada foi encontrada nas placas ateromatosas. No entanto, quatro amostras (13,3%) foram positivas para a presen?a de bact?rias. Destas, tr?s participantes eram dentados, sendo dois portadores de periodontite cr?nica severa generalizada e um de periodontite cr?nica severa localizada. Nenhum deles relatou a realiza??o de procedimentos associados a poss?veis epis?dios de bacteremia, como tratamento endod?ntico, exodontia nos ?ltimos seis meses ou algum procedimento cir?rgico odontol?gico. CONCLUS?O: As bact?rias periodontopatog?nicas estudadas n?o foram encontradas nas placas ateromatosas, n?o pudendo ser estabelecida a preval?ncia destes pat?genos e nem os fatores associados ? presen?a deles nas placas, mas, a detec??o das amostras positivas para bact?rias abre caminhos para que outros pat?genos periodontais e n?o periodontais sejam estudados na tentativa de elucidar de maneira definitiva a associa??o ou n?o entre a doen?a periodontal e/ou outras infec??es e a aterosclerose, atrav?s da presen?a destas bact?rias nos ateromas
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Prote?mica de Chromobacterium violaceum submetida ? microgravidade simuladaSantos, Jonathas Diego Lima 15 December 2017 (has links)
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Previous issue date: 2017-12-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Chromobcterium violaceum (C. violaceum) ? uma bact?ria Gram-negativa, encontrada em regi?es tropicais e subtropicais, considerada organismo modelo de vida livre. Alguns estudos prote?micos realizados com esta bact?ria demonstraram sua capacidade de adapta??o a desafios ambientais, como alta concentra??o de ferro e exposi??o ao estresse oxidativo. No entanto, nenhum estudo foi feito com esta esp?cie submetida ? microgravidade simulada (MGS), ou seja, em condi??es em que a gravidade ? artificialmente reduzida para menos de 1xg. Estudos MGS podem ser importantes para entender as modula??es em n?vel molecular sofridas pelos organismos vivos. Portanto, o objetivo deste estudo foi caracterizar a resposta de C. violaceum, como organismo modelo de vida livre, cultivado em MGS, usando t?cnicas de prote?mica para entender como a bact?ria responde a esse estresse. A MGS foi conseguida por meio da rota??o do vessel ao redor do eixo horizontal perpendicular ao vetor gravitacional nos sistemas de cultura de c?lulas rotativas - Rotating Cell Culture Systems ? (RCCS4). MGS foi conduzido a uma velocidade de 40 rpm por um per?odo de 12 horas para obter a curva de crescimento a cada 2 horas. Prote?nas totais foram extra?das de amostras de cultura de c?lulas bacteriana coletada ?s 5 e 12 horas, correspondendo as fases exponenciais inicial (MG5) e tardia (MG12), respectivamente, tendo a curva de crescimento como refer?ncia. Ap?s a tripsiniza??o, as amostras foram analisadas em espectr?metro de massas Q-TOF. Como resultado um total de 212 prote?nas durante ?s 5h de crescimento e 192 ?s 12h foram detectadas, das quais 144 delas foram comuns em ambos os per?odos. No proteoma de C. violaceum obitido em 5h de crescimento 195 prote?nas foram identificadas em gravidade normal (GN5) e 155 prote?nas foram identificadas em MG5, sendo 18 upreguladas, 19 downreguladas e 17 expressas somente na condi??o de MG5. No proteoma obtido em 12h de crescimento, 165 prote?nas foram identificadas em gravidade normal (GN12) e 173 em MG12, das quais, 17 foram upreguladas, 22 downreguladas e 28 expressas somente na condi??o de MG12 Al?m disso, foi poss?vel identificar 25 prote?nas com fun??o desconhecida em MG5 e MG12. Utilizando ferramentas computacionais foi poss?vel construir redes de intera??es prote?na-prote?na (PPI) e as sub-redes contendo grupo de prote?nas com fun??es correlacionadas, analisar vias metab?licas, processos biol?gicos, contexto gen?mico e busca por dom?nios conservados e sequ?ncias hom?logas de prote?nas com fun??o desconhecida. Como resultado, identificamos sub-redes relacionadas com a bioss?ntese de prote?nas, regula??o da transcri??o e tradu??o, resposta ao estresse e metabolismo energ?tico, conclu?mos que as respostas celulares associadas ? express?o diferencial induzida pela MGS levaram ? diminui??o do crescimento de C. violaceum, acompanhado pela regula??o negativa de prote?nas relacionadas com processos transcricionais, traducionais e libera??o de energia por vias aer?bicas e pela regula??o positiva de prote?nas envolvidas no estresse oxidativo, na via anaer?bica e na sobreviv?ncia celular. / Chromobcterium violaceum (C.violaceum) is a Gram-negative bacteria, which has been found at tropical and subtropical regions, considered a free living model organism. Some proteomic studies performed with this bacterium have demonstrated its ability to adapt to environmental challenges such as high iron concentration and oxidative stress exposure. However, no study was made with this specie submitted to simulated microgravity (SMG), that is, under conditions in which the gravity is artificially reduced to less than 1xg. MGS studies may be important in understanding the molecular-level modulations undergone by living organisms. Therefore, the aim of this study was to characterize the response of C. violaceum, as free-living model organism, cultured at MGS, using proteomics techniques in order to understand how this bacterium response to this stress. The SMG was achieved by rotating the vessel around the horizontal axis perpendicular to the gravitational vector in Rotating Cell Culture Systems (RCCS4). SMG was conducted at a speed of 40 rpm for a period of 12 hours to obtain the growth curve every 2 hours. Total protein extraction was made in two times: 5 and 12 hours, corresponding to early (MG5) and late (MG12) exponential phase, respectively, taking the growth curve as a reference. After trypsinization, samples were analyzed with Q-TOF mass spectrometer. As a result a total of 212 proteins during 5h of growth and 192 at 12h were detected, of which 144 of them were common in both periods. We detected 155 proteins during MG5, from which 18 proteins were upregulated, 19 down-regulated and 17 proteins were exclusive when compared to GN5. In the proteome obtained in 12h of growth, 165 proteins were identified in normal gravity (GN12) and 173 in MG12, of which, 17 were upregulated, 22 were downregulated and 28 expressed only in MG12 condition. In addition, it was possible to identify 25 proteins with unknown function in MG5 and MG12. Using computational tools it was possible to construct networks of protein-protein interactions (PPI) and sub-networks containing group of proteins with correlated functions, to analyze metabolic pathways, biological processes, genomic context and search for conserved domains and homologous sequences of proteins with unknown function . As a result, we identified sub-networks related to protein biosynthesis, transcription regulation and translation, stress response and energetic metabolism, we conclude that the cellular responses associated with differential expression induced by MGS led to a decrease in the growth of C. violaceum, accompanied by the negative regulation of proteins related to transcriptional, translational and energy release by aerobic pathways and by the positive regulation of proteins involved in oxidative stress, anaerobic pathway and cell survival.
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Uso da terapia larval no tratamento de ?lceras cr?nicas em pacientes diab?ticos no Hospital Universit?rio Onofre Lopes- Natal, RNPinheiro, Mar?lia Augusta Rocha de Queiroz 27 May 2014 (has links)
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Previous issue date: 2014-05-27 / A terapia larval ? a utiliza??o de larvas est?reis no desbridamento de feridas. Atualmente essa t?cnica vem sendo bastante utilizada na Europa, Estados Unidos da Am?rica e Israel, dentre outros pa?ses, entretanto, ainda n?o foi implementada rotineiramente no Brasil e n?o h? relatos de sua aplica??o utilizando larvas da mosca Chrysomya megacephala em pacientes humanos. O presente trabalho objetivou avaliar o desbridamento de ?lceras de dif?cil cicatriza??o utilizando larvas de C. megacephala. Cinco pacientes com ?lceras cr?nicas foram inclu?dos no estudo ap?s responderem a um question?rio, serem esclarecidos sobre os poss?veis riscos e benef?cios da terapia larval e assinarem o Termo de Consentimento Livre e Esclarecido ? TCLE. Antes das aplica??es, foram colhidas amostras para identifica??o das bact?rias presentes nas ?lceras. Ap?s essa etapa, as ?lceras foram avaliadas antes e durante o tratamento atrav?s de registro fotogr?fico, mensura??o de di?metros e avalia??o dos percentuais de tecido necr?tico e de granula??o. A avalia??o foi seguida da aplica??o de aproximadamente cinco larvas est?reis de 2? est?dio de C. megacephala por cm2 de les?o. Os curativos com larvas foram trocados ap?s 48 horas e com 48 horas de intervalo entre as aplica??es. As ?lceras dos pacientes inclu?dos no trabalho apresentaram car?ter polimicrobiano e em todas elas foi isolada a esp?cie Pseudomonas aeruginosa. Todos os pacientes submetidos ? terapia larval apresentaram redu??o significativa do percentual de necrose e aumento do tecido de granula??o na superf?cie das ?lceras e uma consequente melhora no decorrer do tratamento. / Larval therapy is the use of sterile larvae in the debridement of wounds. Currently this technique has been widely used in Europe, the U.S.A., and Israel, among other countries, however, has not been implemented in Brazil yet, and there are no reports of its application using larvae of the fly Chrysomya megacephala in human patients. This study aimed to evaluate the debridement of ulcers difficult to heal by using larvae of C. megacephala. Five patients with chronic ulcers were included in the study after answering a questionnaire, to be informed about the possible risks and benefits of larval therapy and signed a Free, Prior and Informed Consent. Before the applications, samples were collected for identification of the bacteria in the ulcers. After this step, the ulcers were evaluated before and during treatment by photographic recording, measurement and evaluation of diameters, percentage of necrotic tissue and granulation. The evaluation was followed by the application of approximately 5 second instar sterile larvae of C. megacephala per cm2 of lesion. Dressings with larvae were exchanged after 48 hours with 48 hours between applications. The patients? ulcers included in this study had polymicrobial nature and in all of them was isolated Pseudomonas aeruginosa species. All patients underwent larval therapy showed a reduction in the percentage of necrosis, increase of granulation tissue on the surface of ulcers and a consequent improvement during treatment.
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Neue Untersuchungsmöglichkeiten mit dem BacT/Alert 3D (bioMèrieux) Mykobakterien-Testsystem: -Empfindlichkeitstestung von M. tuberculosis gegenüber Protionamid und Linezolid- Testung von Wirkstoffkombinationen bei MykobakterienUlber, Heidi 25 January 2017 (has links)
In der vorliegenden Arbeit wurden neue Untersuchungsmöglichkeiten mit dem BacT/Alert 3D Mykobakterien-Testsystem erprobt. Erstens wurden Untersuchungen durchgeführt, um die Testkonzentrationen für Protionamid (PTH) und Linezolid (LIZ) für die standardmäßige Empfindlichkeitstestung von M. tuberculosis (Mtb) mit dem BacT/Alert 3D-System festzulegen. Dazu wurden die MHK-Werte für 32 Mtb-Stämme bestimmt: Referenzstamm Mtb H37Rv, sensible Patientenstämme, Patientenstämme mit verschiedenen Resistenzen (u. a. PTH-Resistenz) sowie eigens für die Arbeit isolierte LIZ-resistente Mutanten. Die PTH-MHK betrug für 20 von 21 sensiblen Mtb-Stämmen einschließlich des Referenzstammes Mtb H37Rv 0,125 - 1 mg/l (0,25 mg/l bei 11 von 21 Stämmen). Lediglich ein Stamm mit Resistenz gegenüber Isoniazid, Ethambutol und Streptomycin fiel mit einer etwas erhöhten PTH-MHK von 2 mg/l auf. Sechs PTH-resistente Stämme (z. T. mit anderen Resistenzen gegenüber Erstrang-Antituberkulotika) zeigten PTH-MHK von 4 - 16 mg/l. Die Gruppen der PTH-sensiblen und resistenten Stämme zeigten ein bimodales Verteilungsmuster, das mit einem Schwellenwert von 2 mg PTH/l gut zu differenzieren ist. Für die standardmäßige Durchführung der Empfindlichkeitstestung gegenüber PTH mit dem BacT/Alert 3D-System empfehlen wir deshalb eine PTH-Testkonzentration von 2 mg/l.
Die LIZ-MHK betrug für 20 sensible Mtb-Stämme (inklusive Referenzstamm Mtb H37Rv) und sieben Stämme mit verschiedenen Resistenzen gegenüber Erstrang-Antituberkulotika 0,25 - 2 mg/l (0,5 mg/l bei 17 von 27 Stämmen). Für die vier isolierten LIZ-resistenten Mutanten betrug die LIZ-MHK 8 - 16 mg/l. Es zeigt sich auch bei der Verteilung der LIZ-MHK ein bimodales Verteilungsmuster; die Gruppen der sensiblen und resistenten Stämme sind gut zu differenzieren. Wir empfehlen für die standardmäßige Durchführung der Empfindlichkeitstestung gegenüber LIZ mit dem BacT/Alert 3D-System eine LIZ-Testkonzentration von 4 mg/l. Die festgestellten MHK-Werte von PTH und LIZ und die vorgeschlagenen Testkonzentrationen entsprechen Ergebnissen aus der Literatur, die mit ähnlichen Methoden erhoben wurden.
Zweitens wurden mit dem BacT/Alert 3D-System Untersuchungen zur Kombinationstestung von Antituberkulotika bei Mtb und Stämmen des MAC-Komplexes durchgeführt, bisher liegen keine Publikationen für Untersuchungen von Wirkstoff-Kombinationen bei Mykobakterien mit diesem System vor. Es wurde geprüft, ob die MHK eines Antituberkulotikums durch die Zugabe einer subinhibitorischen Menge eines anderen Antituberkulotikums verändert wird. Bei Mtb wurden dazu folgende Kombinationen geprüft: Rifampicin (RMP) + LIZ, Moxifloxacin + LIZ, Isoniazid + PTH, RMP + PTH, PTH + LIZ. In keinem Fall konnten signifikante Effekte beobachtet werden. Ein tendenziell synergistischer Effekt der PTH-RMP-Kombination beim Stamm Mtb H37Rv (Reduktion der RMP-MHK um eine Stufe) wurde durch die Analyse der Wachstumskinetik des Stammes unterstützt. Bei zufällig ausgewählten Stämmen des MAC-Komplexes wurde die Kombination Ciprofloxacin (CIP) + Ethambutol (EMB) geprüft. Es zeigte sich bei sieben von zehn Stämmen eine Reduzierung der CIP-MHK um mindestens drei Stufen bei Zugabe einer subinhibitorischen Konzentration von EMB. Dieser synergistische Effekt wurde bereits in den 1990er Jahren mit einer ähnlichen Methode festgestellt, allerdings ohne die Stämme des MAC-Komplexes zu differenzieren (Arbeitsgruppe von S. Hoffner). Interessanterweise handelte es sich bei den von uns untersuchten Stämmen, bei denen dieser synergistische Effekt nachgewiesen wurde, um M. avium-Stämme. Diese Problematik sollte weiter verfolgt werden, da sich daraus Konsequenzen für die Therapieempfehlung ergeben könnten.
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Identifica??o e determina??o de resist?ncia antimicrobiana em isolados nosocomiais de Acinetobacter baumanniiRaro, Ot?vio Hallal Ferreira 30 September 2011 (has links)
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Previous issue date: 2011-09-30 / Acinetobacter baumannii is an important opportunistic pathogen commonly associated with nosocomial infections, especially in patients hospitalized in intensive care units (ICUs). This microorganism is renowned for its ability to survive under adverse conditions in the environment for extended periods, as well as to rapidly acquire resistance to antimicrobial drugs. Nowadays, the increasing antimicrobial resistance of A. baumannii has been a great challenge for the medical community, since there are few effective options for the treatment of infections caused by this organism. The aim of this study was to evaluate the presence of the A. baumannii from an ICU environment and to characterize the antimicrobial drug resistance of the isolates obtained, as well as of the isolates from patients in ICU of the same hospital in which it was collected environmental samples. For this, 886 environmental and gloves samples were collected from an ICU of S?o Lucas Hospital, Porto Alegre, Brazil, and 46 clinical isolates were obtained from the Laboratory of the same hospital. After the identification of the isolates as A. baumannii by PCR using as target 16S rDNA and blaOXA-51 genes, the resistance to 20 antimicrobial drugs and the production of metallo-beta-lactamases were evaluated in isolates presenting carbapenem reduced susceptibility. Also, it was evaluated the presence of integrons and blaOXA-23 and blaIMP genes by PCR. A. baumannii was identified in 9.6% of environmental and glove samples collected. High percentage of multiresistant (MDR) isolates was found, as well as it was detected high rates of reduced susceptibility to carbapenems. All 89 isolates integron positive were MDR. Between isolates with reduced susceptibility to carbapenems, all presented blaOXA-23, and 41.4% non-clinical and 54% clinical carried the blaIMP. High resistance to polymyxin B was detected, mainly in non-clinical isolates. Although high prevalence has been found in clinical and non-clinical isolates, the latter constitute a great concern, because they can indicate the hospital environment as a reservoir of MDR A. baumannii. / Acinetobacter baumannii ? um importante pat?geno oportunista comumente associado a infec??es nosocomiais, especialmente em pacientes hospitalizados em unidades de tratamento intensivo (UTIs). Este organismo ? reconhecido por sua capacidade de sobreviver em condi??es adversas no ambiente por per?odos prolongados, bem como de facilmente adquirir resist?ncia a drogas antimicrobianas. Atualmente, a crescente resist?ncia antimicrobiana de A. baumannii tem constitu?do um grande desafio para a comunidade m?dica, uma vez que existem poucas op??es efetivas para o tratamento de infec??es causadas por este microrganismo. O objetivo deste estudo foi avaliar a presen?a de A. baumannii no ambiente de uma UTI e caracterizar a resist?ncia a drogas antimicrobianas dos isolados obtidos, bem como de isolados de pacientes internados na UTI do mesmo hospital no qual as amostras ambientais foram coletadas. Para tanto, 886 amostras ambientais e de luvas foram coletadas de uma UTI do Hospital S?o Lucas, Porto Alegre, Brasil, e 46 isolados cl?nicos foram obtidos no Laborat?rio do mesmo hospital. Ap?s a identifica??o dos isolados como A. baumannii atrav?s de PCR utilizando como alvos os genes rDNA 16S e blaOXA-51, foram determinadas a resist?ncia a 20 drogas antimicrobianas previstas pelo CLSI e a produ??o de metalo-betalactamases em isolados com suscetibilidade reduzida aos carbapen?micos. Tamb?m foi avaliada a presen?a de integrons e dos genes blaOXA-23 e blaIMP atrav?s de PCR. A. baumannii foi identificado em 9,6% das amostras ambientais e de luvas coletadas. Obteve-se um alto percentual de isolados multirresistentes (MDR), assim como foram detectadas alta taxas de suscetibilidade reduzida aos carbapen?micos. Todos os 89 isolados que apresentaram integrons foram MDR. Dentre os isolados com suscetibilidade reduzida aos carbapen?micos, todos apresentaram o gene blaOXA-23, e 41,4% n?o-cl?nicos e 54% cl?nicos carrearam o gene blaIMP. Alta resist?ncia ? polimixina B foi detectada, principalmente em isolados n?o-cl?nicos. Embora alta preval?ncia de resist?ncia antimicrobiana tenha sido encontrada em isolados cl?nicos e n?o cl?nicos, os ?ltimos constituem grande preocupa??o, pois podem indicar o ambiente hospitalar como um reservat?rio de A. baumannii MDR.
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Caracteriza??o de biofilmes polimicrobianos de Candida parapsilosis com Staphylococcus aureus ou Acinetobacter sp. e avalia??o de sua sensibilidade a sanitizantes e a antimicrobianosMattiello , Shaiana Paula 25 February 2015 (has links)
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Previous issue date: 2015-02-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Funda??o de Amparo ? Pesquisa do Estado do Rio Grande do Sul - FAPERGS / The species of the ?C. parapsilosis complex? are common etiological agents of nosocomial candidemia, and C. parapsilosis sensu stricto is one of non-albicans Candida species with the highest incidences in clinical infections, primarily related to implanted medical devices. In this study, we identified 29 isolates comprising the ?C. parapsilosis complex? to species level, all previously obtained from the hospital environment and medical tools. The isolates were also characterized for in vitro activity of aspartyl proteinase and phospholipase, as well as for their ability to form biofilms. The isolates identified as C. parapsilosis sensu stricto were also evaluated for their capability to interact with Staphylococcus aureus and Acinetobacter sp. in two-species polymicrobial biofilms. These biofilms were then analyzed for their tolerance to treatments with increasing concentrations of antimicrobials drugs and sanitizers. The results indicated that 75.9% of the isolates were identified as C. parapsilosis sensu stricto, 24.1% as Candida metapsilosis and none as Candida orthopsilosis. Regarding C. parapsilosis sensu stricto, all isolates were very strong producers of aspartyl proteinase, and 13.6% of phospholipase. Regarding C. metapsilosis, 71.4% and 14.3% of the isolates showed very strong aspartyl proteinase and phospholipase activity, respectively. Moreover, all isolates were able to form biofilm on polystyrene surface. Among the C. parapsilosis sensu stricto isolates, 9.1%, 45.4% and 45.4% were strong, moderate and weak biofilm producers, respectively. Regarding C. metapsilosis, 71.4% were moderate and 28.6% were weak biofilm producers.We also demonstrated that C. parapsilosis sensu stricto was capable of associating synergistically with both bacteria tested, since in polymicrobial biofilms a significantly higher number of bacterial cells adhered, compared to their own monomicrobial condition. However, bacterial cells did not interfere on the efficiency of yeast biofilm formation. When testing sanitizers, we showed that 70% ethyl alcohol and 1% sodium hypochlorite were effective to significantly decrease the number of viable cells, although they have not been able to eliminate the microbial populations of the biofilms. Our data also showed that the cells from all monomicrobial biofilms exhibited elevated tolerance to their respective antimicrobial drugs, at higher doses than their pre-determined minimal inhibitory concentration values. Nevertheless, biofilms of 6, 12 and 24 h of C. parapsilosis sensu stricto presented some decrease in cell viability to the treatment with ketoconazole, whereas 48 h biofilms were resistant to this antifungal. In polymicrobial biofilms, the bacterial cells did not affect the tolerance of yeast isolates to this antimicrobial. Conversely, S. aureus and Acinetobacter sp. cells were even more tolerant to the treatment with vancomycin and polymyxin B, respectively, when they were in polymicrobial biofilms, which was significantly different from their respective monomicrobial condition.The results from this work revealed the ability of ?C. parapsilosis complex? isolates from nosocomial environment to express important virulence factors, as well as to interact synergistically with bacterial species of clinical importance. This data is clinically relevant, since such phenotypic features may represent an important risk in terms of nosocomial infection to hospitalized patients. / As esp?cies do ?complexo Candida parapsilosis? mostram-se como frequentes agentes etiol?gicos de candidemias nosocomiais, sendo a C. parapsilosis sensu stricto uma das esp?cies n?o-albicans de Candida de maior incid?ncia em infec??es cl?nicas, estando relacionada principalmente com dispositivos m?dicos implantados. Neste estudo, identificamos, em n?vel de esp?cie, 29 isolados pertencentes ao ?complexo Candida parapsilosis?, todos previamente obtidos a partir do ambiente hospitalar e de dispositivos m?dicos. Os isolados tamb?m foram caracterizados quanto ? atividade in vitro de aspartil proteinase e fosfolipase, e quanto ? habilidade de formar biofilmes. Os isolados identificados como C. parapsilosis sensu stricto foram avaliados quanto ? capacidade de interagir com Staphylococcus aureus e Acinetobacter sp. no desenvolvimento de biofilmes polimicrobianos de duas esp?cies. Estes biofilmes foram ent?o analisados quanto ? sua capacidade de tolerar o tratamento com concentra??es crescentes de f?rmacos antimicrobianos e sanitizantes. Como resultados, 75,9% dos isolados foram identificados como C. parapsilosis sensu stricto, 24,1% como Candida metapsilosis e nenhum como Candida orthopsilosis. Em rela??o ? C. parapsilosis sensu stricto, todos os isolados mostraram-se como produtores muito fortes de aspartil proteinase e 13,6% de fosfolipase. Em rela??o ? C. metapsilosis, 71,4% e 14,3% dos isolados apresentaram atividade muito forte de aspartil proteinase e fosfolipase, respectivamente.Al?m disso, todos os isolados foram capazes de formar biofilme em superf?cie de poliestireno. Dentre os isolados de C. parapsilosis sensu stricto, 9,1%, 45,4% e 45,4% mostraram-se como produtores fortes, moderados e fracos de biofilme, respectivamente. Em rela??o aos de C. metapsilosis, 71,4% foram moderados e 28,6% foram fracos formadores de biofilme. Demonstramos tamb?m que a C. parapsilosis sensu stricto foi capaz de se associar de forma sin?rgica com ambas as bact?rias testadas, pois nos biofilmes polimicrobianos um n?mero significativamente maior de c?lulas bacterianas se aderiram em compara??o ? sua condi??o monomicrobiana. Entretanto, as bact?rias n?o interferiram na efici?ncia de forma??o de biofilmes da levedura. O tratamento com sanitizantes mostrou que o ?lcool et?lico a 70% e o hipoclorito de s?dio a 1% foram eficazes em diminuir significativamente o n?mero de c?lulas vi?veis, mas n?o foram capazes, mesmo assim, de eliminar as popula??es microbianas dos biofilmes. Al?m disso, nossos dados mostraram que as c?lulas integrantes de todos os biofilmes monomicrobianos avaliados apresentaram elevada toler?ncia aos seus respectivos antimicrobianos, em doses superiores aos seus valores de concentra??o inibit?ria m?nima, previamente determinados.Mesmo assim, os biofilmes de C. parapsilosis sensu stricto de 6, 12 e 24 h mostraram alguma perda de viabilidade celular ao tratamento com cetoconazol, enquanto biofilmes de 48 h se mostraram resistentes a este antif?ngico. Nos biofilmes polimicrobianos, a presen?a das c?lulas bacterianas n?o influenciou a toler?ncia das leveduras ao antimicrobiano. Por outro lado, as c?lulas de S. aureus e Acinetobacter sp. foram ainda mais tolerantes ao tratamento com vancomicina e polimixina B, respectivamente, quando em biofilmes polimicrobianos, de forma significativa em compara??o ?s suas respectivas condi??es monomicrobianas. Os resultados deste trabalho revelaram a capacidade de isolados do ?complexo C. parapsilosis? do ambiente nosocomial de expressar importantes fatores de virul?ncia, bem como de interagir sinergicamente com bact?rias de import?ncia cl?nica. Em conjunto, estas informa??es mostram-se de grande relev?ncia cl?nica, em fun??o de tais caracter?sticas fenot?picas representarem um importante risco em termos de infec??o hospitalar a pacientes internados.
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Uso da espectroscopia do infravermelho pr?ximo e t?cnicas multivariadas para diferenciar escherichia coli e salmonella enteritidis inoculadas em polpa de fruta (abacaxi)Marques, Aline de Sousa 31 July 2013 (has links)
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Previous issue date: 2013-07-31 / Aiming to consumer s safety the presence of pathogenic contaminants in
foods must be monitored because they are responsible for foodborne outbreaks
that depending on the level of contamination can ultimately cause the death of
those who consume them. In industry is necessary that this identification be fast
and profitable. This study shows the utility and application of near-infrared (NIR)
transflectance spectroscopy as an alternative method for the identification and
classification of Escherichia coli and Salmonella Enteritidis in commercial fruit pulp
(pineapple). Principal Component Analysis (PCA), Independent Modeling of Class
Analogy (SIMCA) and Discriminant Analysis Partial Least Squares (PLS-DA) were
used in the analysis. It was not possible to obtain total separation between
samples using PCA and SIMCA. The PLS-DA showed good performance in
prediction capacity reaching 87.5% for E. coli and 88.3% for S. Enteritides,
respectively. The best models were obtained for the PLS-DA with second
derivative spectra treated with a sensitivity and specificity of 0.87 and 0.83,
respectively. These results suggest that the NIR spectroscopy and PLS-DA can be
used to discriminate and detect bacteria in the fruit pulp / Visando ? seguran?a do consumidor, ? de extrema import?ncia identificar
a presen?a de contaminantes patog?nicos nos alimentos, pois os mesmos s?o
respons?veis por surtos alimentares que dependendo do n?vel de contamina??o
pode chegar a causar a morte de quem os consome. Na industria h? uma
necessidade de que essa identifica??o de contaminantes seja r?pida e rent?vel.
Este estudo mostra a aplica??o e utilidade de medidas espectrais de
transflect?ncia no infravermelho pr?ximo (NIR) como um m?todo alternativo para
a identifica??o e classifica??o de Escherichia coli e Salmonella Enteritidis em
polpa de fruta comercial (abacaxi). An?lise de Componentes Principais (PCA),
Modelagem Independente por Analogia Classe (SIMCA) e An?lise Discriminante
por M?nimos Quadrados Parciais (PLS-DA) foram utilizados na an?lise. N?o foi
poss?vel obter uma separa??o total entre as amostras usando PCA e SIMCA. O
PLS-DA apresentou bom desempenho na capacidade de predi??o alcan?ando
87,5% para E. coli e 88,3% para S. Enteritides, respectivamente. Os melhores
modelos obtidos para o PLS-DA com os espectros tratados com segunda
derivada apresentaram sensibilidade e especificidade de 0,87 e 0,83,
repectivamente. Estes resultados sugerem que a espectroscopia NIR e PLS-DA
podem ser usados para discriminar e detectar bact?rias na polpa da fruta
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