The kinetics of lipase activity and hydrolytic rancidity of raw, parboiled, and extruded rice bran during storage

The main problem related to rice bran use is that it goes rancid right after its production. The objective of the present study was to apply a mathematical model to evaluate the kinetics of the lipase activity and hydrolytic rancidity of the raw rice bran (RRB), extruded rice bran (ERB), and parboiled rice bran (PRB) stored in low density polyethylene bags at room temperature for 180 days. Extrusion and parboiling were efficient in preventing free fatty acid formationin ERB and PRB.Extrusion reduced the velocity constant of lipase activity as compared to that of RRB while parboiling increased it, and both decreased the lipase activity after equilibrium from 150 days. The extrusion and parboiling treatments increased the velocity constants for the liberation of free fatty acids although the equilibrium was reached with reduced production of free fatty acids in relation to the production of raw rice bran after 150 days ofstorage. Extrusion proved the best treatment under the storage temperature conditions of rice bran from cultivar BRS Primavera.

Secretion of five extracellular enzymes by strains of chromoblastomycosis agents

The gelatinase, urease, lipase, phospholipase and DNase activities of 11 chromoblastomycosis agents constituted by strains of Fonsecaea pedrosoi, F. compacta, Phialophora verrucosa, Cladosporium carrionii, Cladophialophora bantiana and Exophiala jeanselmei were analyzed and compared. All strains presented urease, gelatinase and lipase activity. Phospholipase activity was detected only on five of six strains of F. pedrosoi. DNase activity was not detected on the strains studied. Our results indicate that only phospholipase production, induced by egg yolk substrate, was useful for the differentiation of the taxonomically related species studied, based on their enzymatic profile.

Avaliação comparativa da eficácia e toxicidade do antimoniato de N-metil-glucamina e do Estibogluconato de Sódio BP88® no tratamento da leishmaniose cutânea localizada

Foi realizado ensaio clínico randomizado simples cego para comparar a eficácia e a toxicidade do estibogluconato de Na+ (ES) e o antimoniato de N-metil glucamina, o Glucantime®(GL). Sessenta e três pacientes foram distribuídos em um dos dois grupos: 32 pacientes foram tratados com GL e 31 pacientes com o ES. Ambos os grupos receberam 15mg Sb+5/kg/dia durante 20 dias. A toxicidade foi avaliada através do ECG, dosagens de uréia, creatinina, TGO, TGP, fosfatase alcalina, amilase, e lipase, avaliados antes do tratamento, nos dias 10 e 20 do tratamento, e 90 dias após o término do mesmo. No grupo tratado com GL 81% (26/32) dos pacientes curaram, comparados com 77% (24/31) no grupo do ES. Um paciente em cada grupo não respondeu ao tratamento. TGO, TGP, amilase, e lipase foram mais elevadas no grupo que usou o ES (p < 0,05). Concluiu-se que, a eficácia de ambos os tratamentos foram similares, apesar da maior toxicidade observada no grupo tratado com ES.

Digestibilidade aparente dos nutrientes e energia de ração suplementada com enzimas digestivas exógenas para juvenis de tambaqui (Colosssoma macropomum Cuvier, 1818)

O experimento foi conduzido com o objetivo de avaliar o efeito da adição de um compelxo multienzimático exógeno composto de amilase, protease, lipase e celulase, em rações de juvenis de tambaqui, sobre os coeficientes de digestibilidade aparente (CDa) da proteína bruta (PB), extrato etéreo (EE), carboidratos (ENN) e energia bruta (EB). O delineamento experimental foi inteiramente casualizado com quatro tratamentos (quatro níveis de inclusão de enzimas, 0,0; 0,05; 0,10; e 0,15 %), três repetições (no tempo) e 10 peixes por unidade experimental. Foram utilizados 40 juvenis de tambaqui, com peso médio de 155,0 ± 0,49 g, distribuídos em quatro tanques de alimentação de 500 l, recebendo refeições à vontade das 8 às 12h, a cada hora. Em seguida os animais foram transferidos para coletores de fezes (200 l), onde permaneceram até às 18h, sendo a coleta de dejetos realizada a cada hora. A determinação dos CDa foi realizada pelo método indireto, sendo utilizado como indicador externo 0,5% de óxido de cromo-III (Cr2O3) incorporado à ração. Os resultados demonstraram que a suplementação das dietas com enzimas exógenas para juvenis de tambaqui aumenta a digestibilidade aparente dos nutrientes e energia bruta, no nível de inclusão de 0,05% (P<0,05%).

Índice lipásido Seabra: seu valor no diagnóstico da tuberculose

The determination of blood lipase has been proposed by SEABRA as a method for detecting predisposition to initial or subsequent stages of tuberculosis; normal subjects having high titers (8-12 units), tuberculous patients low ones (5-7), falling to zero in advanced stages of the disease. An assay of the method has been made by the AA. in sera of 238 non tuberculous subjects (419 tests) and 207 tuberculous ones (456 tests) following the technical procedures described by SEABRA. All of them had their Roentgenographies taken at the same day of blood collection. Factors interfering with blood lipase values in tuberculosis are discussed. A relationship between the course of the disease and the serum lipase could not be confirmed. High and low values were found in initial as well as in advanced cases. Our results are in agreement with those recorded in the literature (Figs. I and II). It seems that the general condition, rather than pulmonary lesions are responsible for the blood lipase values. There was no direct relationship between blood lipase titer and severity of pulmonary tuberculosis; however the data presented in this paper do not agree with such correlation, stated by SEABRA, FERNANDES and VICENTE.

Clearing factor pancreático

Dosou-se o "clearing factor" (lipase lipoproteica), em pâncreas de ratos normais após serem submetidos a algumas condições experimentais. As seguintes conclusões podem ser extraídas: a) O pãncreas é o órgão mais rico nesta enzima (8 vezes mais que o tecido adiposo, até então considerado o mais rico em CF); b) O jejum total de 48 horas diminui significamente a atividade de CF; c) O complamin, o derivado do ácido nicotínico, agindo sobre a arteriosclerose experimental, não afeta a atividade da enzima; d) O ácido épsilon-aminocapróico (AEAC) potente antagonista da heparina, inibe a ativdade do Cf pancreático; e) Ratos com arteriosclerose experimental apresentam níveis diminuídos desta enzima no pâncreas.

On the mechanism of protective action of cold acclimatization against carbon tetrachloride - and ethionine-induced fatty liver

In this study the hepatic lipoprotein lipase (LPL), activity was evaluated in adult female mice acclimatized at 5-C and submitted to carbon tetrachloride (CCI) or ethionine, in order to determine the possible role of this enzuyme in the fatty liver. The results were compared with those obtained in mice kept at room temperature (27-C) that the same hepatoesteatosis inducing agent. In contrast to animals kept at room temperature, in cold aclimatized mice neither the enhancement of the LPL-liver activity by the action of CCI or ethionine occurred nor the development of fatty infiltration in the liver was observed. We conclude that the low temperature induced a protective effect against CCI or ethionine-induced fatty liver that was correlated with the no-increase of the hepatic LPL activity.

Study of virulence factors in coagulase-negative staphylococci isolated from newborns

Coagulase-negative staphylococci (CNS) have been identified as the etiological agent in various infections and are currently the microorganisms most frequently isolated in nosocomial infections. However, little is known about the virulence factors produced by CNS that contribute to the pathogenesis of infections caused by these microorganisms. The study of CNS isolated from infectious processes of newborns hospitalized in the Neonatal Unit of the Hospital of the Botucatu Medical School, Unesp, indicated Staphylococcus epidermidis as the most frequently isolated species (77.8%), which was also associated with clinically significant situations. The analysis of virulence factors revealed the production of slime in 20 (17.1%) of all CNS samples isolated and the synthesis of a broad spectrum of enzymes and toxins, including hemolysins (19.6%), lipase (17.1%), lecithinase (3.4%), DNAse (15.4%), thermonuclease (7.7%), and enterotoxin A, B or C (37.6%). Taking into consideration that the etiological importance of CNS has often been neglected, the present investigation confirmed that these microorganisms should not be ignored or classified as mere contaminants.

Enzimas digestivas exógenas na alimentação de juvenis de tambaqui

O objetivo deste trabalho foi avaliar o efeito da adição na ração das enzimas digestivas exógenas amilase, lipase e protease sobre o desempenho de tambaqui, em três experimentos independentes. Em cada experimento foi avaliado o efeito da inclusão de uma enzima na ração em diferentes porcentagens: 0,0, 0,05, 0,1 e 0,2%, cada uma com quatro repetições, com 28 dias de duração. Foram realizadas biometrias do peso inicial, para homogeneização da amostra, e do peso final a fim de verificar o efeito dos tratamentos sobre o desempenho dos peixes. Em cada unidade experimental foram estocados dez peixes, alimentados duas vezes ao dia (8 e 14h) até a saciedade aparente, com ração comercial extrusada com 28% de proteína bruta, triturada, adicionada de enzima e depois peletizada. Ao final do experimento, o ganho de peso, a conversão alimentar aparente e o crescimento específico dos peixes, apresentaram diferenças significativas entre os tratamentos. As enzimas exógenas amilase a 0,05% e lipase a 0,2% na ração influenciaram o desempenho zootécnico de juvenis de tambaqui. A adição de protease exógena não apresenta a mesma influência.

Desempenho e atividades enzimáticas em girinos de rã-touro

O objetivo deste trabalho foi avaliar o desempenho e as atividades das enzimas digestivas de girinos de rã-touro, alimentados com ração comercial durante 60 dias, com um girino por litro, em caixas com 30 L de água. Os parâmetros medidos quinzenalmente foram: sobrevivência, comprimento, peso final, consumo de ração, e a atividade de amilase, lipase e tripsina. O maior crescimento dos girinos foi do 15º ao 45º dia - 20,61 mm. Durante os primeiros 15 dias, os girinos apresentaram a maior taxa de crescimento específico, 16,73% por dia. Do 45º ao 60º dia, os girinos apresentaram o maior ganho de peso, 3,98±0,73 g, o maior consumo de ração, 14,40±1,14 g, e a melhor conversão alimentar, 3,67:1,0±0,18. Houve aumento significativo da atividade enzimática depois do 30º dia. Observaram-se relações entre as atividades específicas das enzimas e os distintos estágios de desenvolvimento dos girinos.

O emprego de lipases como agentes de resolução cinética de enantiômeros em síntese orgânica: aspectos gerais sobre a influência do solvente

In organic synthesis, lipases are the most frequently used biocatalysts. They are efficient stereoselective catalysts in the kinetic resolution of a wide variety of chiral compounds. The discovery that enzymes possess catalytic activity in organic solvents has made it possible to address the question of reaction medium influence on enzymatic specificity. Perhaps the most exciting and significant development in this emerging area is the discovery that enzyme specificity, in particular enantioselectivity, can be affected by changing from one organic solvent to another. This article discusses the scope and possible mechanistic models of this phenomenon in hydrolases, specially lipases, as well as directions of future research in the area.

Aplicação de lipases microbianas na obtenção de concentrados de ácidos graxos poliinsaturados

Several polyunsaturated fatty acids (PUFA) belonging to the ômega 6 series, such as cis-6,9,12 gamma-linolenic acid, as well as those of the ômega 3 series, such as cis-5,8,11,14,17-eicosapentaenoic acid and cis-4,7,10,13,16,19-docosahexaenoic acid are of considerable interest due to their nutritional and therapeutic properties. Methods used for the concentration of PUFA from natural sources include urea adduct formation, solvent winterization, supercritical fluid extraction and lipase-catalyzed reaction. Lipases are known to have little reactivity on PUFA and these acids can be enriched by selective hydrolysis, direct esterification of glycerol with PUFA and interesterification. Since lipase reactions are advantageous with respect to fatty acid, positional specificities and mild incubation condition, these enzymes are considered to be suitable for the production of PUFA concentrates for medical purposes.

Modificação de óleos e gorduras por biotransformação

The oleochemical industry has a permanent interested in controlling the physical, functional and organoleptical properties of their products and in producing useful derivatives from their raw materials. The potential of biotechnology for developing novel or well-known products at more competitive costs meets the need of this industrial segment in expanding their goals. In this work some technical aspects, problems and perspectives related to the production of oil and fat derivatives using biotransformation techniques are discussed. Particular emphasis is given to the description of biotransformation processes using lipase as catalyst, in view of the great versatility of this enzyme class to mediate typical reactions in this technological sector.

Aplicações sintéticas de lipases imobilizadas em polímeros

The application of biocatalysis is a promising field related to new technologies for organic synthesis. The development of immobilization techniques is very important due to the multiple or repetitive use of a single batch of enzymes and the ability to stop the reaction rapidly, at any stage, by removing the enzymes. In most cases, after immobilization, enzymes and microorganisms maintain or even increase their activity and stability. This work presents an overview of the common methods for lipase immobilization in polymers and applications of these systems to obtain compounds of synthetic interest.

Potencial de biocatálise enantiosseletiva de lipases microbianas

Microbial lipases have a great potential for commercial applications due to their stability, selectivity and broad substrate specificity because many non-natural acids, alcohols or amines can be used as the substrate. Three microbial lipases isolated from Brazilian soil samples (Aspergillus niger; Geotrichum candidum; Penicillium solitum) were compared in terms of their stability and as biocatalysts in the enantioselective esterification using racemic substrates in organic medium. The lipase from Aspergillus niger showed the highest activity (18.2 U/mL) and was highly thermostable, retaining 90% and 60% activity at 50 ºC and 60 ºC after 1 hour, respectively. In organic medium, this lipase provided the best results in terms of enantiomeric excess of the (S)-active acid (ee = 6.1%) and conversion value (c = 20%) in the esterification of (R,S)-ibuprofen with 1-propanol in isooctane. The esterification reaction of the racemic mixture of (R,S)-2-octanol with decanoic acid proceeded with high enantioselectivity when lipase from Aspergillus niger (E = 13.2) and commercial lipase from Candida antarctica (E = 20) were employed.