Meio modificado de cultura para caracterização de Salmonella lactose positiva

Foi desenvolvido um meio modificado de cultura para isolamento e caracterização de enterobactérias, visando especialmente salmonelas fermentadoras da lactose. No chamado "Meio modificado" as colônias das duas estirpes de Salmonella (lactose positivas e lactose negativas) apresentam a morfologia idêntica, o que não ocorre quando são empregados os meios rotineiros à base de lactose, para isolamento de enterobactérias. Esse meio é uma modificação do meio de Hektoen Enteric Agar, do qual retirou-se lactose e adicionou-se xilose e L-lisina. Foi verificado que há possibilidade de diferenciar-se os diversos grupos de enterobactérias, empregando um meio de cultura sem lactose e usando como sistema diferenciador xilose e L-lisina. O meio modificado foi também avaliado quantitativamente comparando o seu poder enriquecedor ou inibitório, ao dos meios de Hektoen Enteric Agar, Brilliant Green Agar e SS Agar para diferentes grupos de enterobactérias.

Isolamento de Salmonella typhimurium fermentadora de lactose, em caso autoctone no Rio de Janeiro

Relata-se o primeiro isolamento no Rio de Janeiro, a partir de um caso de gastroenterite infantil, da variante de Salmonella typhimurium, que se tornou prevalente na cidade de São Paulo. O mesmo padrão de resistência múltipla a agentes antibacterianos foi observado, com sensibilidade à gentamicina, colimicina e a associação sulfametaxazol-trimetoprim. Discutem-se características bacteriológicas das amostras de mesmo comportamento, enfatizando-se a necessidade de adaptação das técnicas bacterio­lógicas visando a sua detecção, que provavelmente vem passando desapercebida pelas técnicas tradicionais.

Análise genética de Salmonella typhimurium ferment adoras de lactose isoladas no Rio de Janeiro

Salmonella typhimurium fermentadoras de lactose são comuns em São Paulo, porém, raras no Rio de Janeiro, onde descrevemos dois isolamentos. Um plasmídeo de 7,4 megadáltons, não auto-transferível, termorresistente e não eliminável pelo alaranjado de acridinafoi identificado em cada uma das duas linhagens isoladas no Rio de Janeiro. O fato de uma dessas linhagens ser derivada de um plasmídeo que originalmente não expressa o caráter fermentação de lactose, permite-nos especular acerca da origem deste caráter nas Salmonellas brasileiras.

Chronic lactose intake modifies the gastric emptying of monosaccharides but not of disaccharides in weanling rats

Ninety-six weanling male Wistar rats were fed for four weeks one of two different chows: a normal rat chow containing 55.5% (w/w) starch (control group, N = 48) or a rat chow in which starch was partially replaced by lactose, in such a way that the experimental group (N = 48) received 35.5% (w/w) starch and 20% (w/w) lactose. The gastric emptying of fluid was then studied by measuring the gastric retention of four test meals containing lactose (5% or 10%, w/v) or glucose + galactose (5% or 10%, w/v). Homogenates of the small intestine were assayed for lactase activity. The gastric retention values were obtained 15 min after orogastric infusion of the liquid meals. The median values for gastric retention of the 5% lactose solutions were 37.7% for the control group and 37.0% for the experimental group (P>0.02). For the 10% lactose solution the median values were 51.2% and 47.9% (P>0.02) for the control and experimental groups, respectively. However, for the 2.5% glucose + 2.5% galactose meal the median gastric retention was lower (P<0.02) in the group fed a lactose-enriched chow (38.5%) than in the control group (41.6%). For the 5% glucose + 5% galactose solution the median values were not statistically different between groups, 65.0% for the control group and 58.8% for the experimental group. The median values of the specific lactase activity in the small intestine homogenate was 0.74 U/g in the control group and 0.91 U/g in the experimental group. These values were not statistically different (P>0.05). These results suggest that the prolonged ingestion of lactose by young adult rats changes the gastric emptying of a solution containing 5% monosaccharides. This adaptation may reflect the desensitization of intestinal nutrient receptors, possibly by an osmotic effect of lactose present in the chow.

Use of nucleotides in weanling rats with diarrhea induced by a lactose overload: effect on the evolution of diarrhea and weight and on the histopathology of intestine, liver and spleen

Until recently, dietary sources of nucleotides were thought not to be essential for good nutrition. Certain states with higher metabolic demands may require larger amounts that cannot be provided by endogenous production. The objective of the present study was to determine the action of nucleotides on the recovery from lactose-induced diarrhea in weaned rats. Thirty-six weanling Fisher rats were divided into two groups. Group 1 received a standard diet and group 2 received a diet containing lactose in place of starch. On the 10th day, six animals per group were sacrificed for histopathological evaluation. The remaining animals were divided into two other subgroups, each with 6 animals, receiving a control diet, a control diet with nucleotides (0.05% adenosine monophosphate, 0.05% guanosine monophosphate, 0.05% cytidine monophosphate, 0.05% uridine monophosphate and 0.05% inosine monophosphate), a diet with lactose, and a diet with lactose and nucleotides. On the 32nd day of the experiment all animals were sacrificed. Animals with diarrhea weighed less than animals without diarrhea. The introduction of nucleotides did not lead to weight gain. Mean diet consumption was lower in the group that continued to ingest lactose, with the group receiving lactose plus nucleotides showing a lower mean consumption. Animals receiving lactose had inflammatory reaction and deposits of periodic acid-Schiff-positive material in intestinal, hepatic and splenic tissues. The introduction of nucleotides led to an improvement of the intestinal inflammatory reaction. In lactose-induced diarrhea, when the stimulus is maintained - lactose overload - the nucleotides have a limited action on the weight gain and on recovery of intestinal morphology, although they have a protective effect on hepatic injury and improve the inflammatory response.

Correlation between lactose absorption and the C/T-13910 and G/A-22018 mutations of the lactase-phlorizin hydrolase (LCT) gene in adult-type hypolactasia

The C/T-13910 mutation is the major factor responsible for the persistence of the lactase-phlorizin hydrolase (LCT) gene expression. Mutation G/A-22018 appears to be only in co-segregation with C/T-13910. The objective of the present study was to assess the presence of these two mutations in Brazilian individuals with and without lactose malabsorption diagnosed by the hydrogen breath test (HBT). Ten milk-tolerant and 10 milk-intolerant individuals underwent the HBT after oral ingestion of 50 g lactose (equivalent to 1 L of milk). Analyses for C/T-13910 and G/A-22018 mutations were performed using a PCR-based method. Primers were designed for this study based on the GenBank sequence. The CT/GA, CT/AA, and TT/AA genotypes (lactase persistence) were found in 10 individuals with negative HBT. The CC/GG genotype (lactase non-persistence) was found in 10 individuals, 9 of them with positive HBT results. There was a significant agreement between the presence of mutations in the LCT gene promoter and HBT results (kappa = -0.9, P < 0.001). The CT/AA genotype has not been described previously and seems to be related to lactase persistence. The present study showed a significant agreement between the occurrence of mutations G/A-22018 and C/T-13910 and lactose absorption in Brazilian subjects, suggesting that the molecular test used here could be proposed for the laboratory diagnosis of adult-type primary hypolactasia.

Produção de lactosacarose por β-frutofuranosidase de bacillus sp nº417 a partir de lactose e sacarose

Entre 1341 linhagens de microrganismos isolados a partir de amostras de solos, flores e frutos e testados quanto à produção de β-frutofuranosidase com atividade de transferência para produção de lactosacarose foi selecionado uma linhagem, identificada como Bacillus sp n°417. Verificou-se que após 8 horas de reação, a proporção de lactose e sacarose 1:1 (p/p) e 20% de concentração de açúcares totais, a uma temperatura de 45°C e pH 5,6 foram as melhores condições para produção de lactosacarose.

Not any type of rice performs equally to improve lactose-induced diarrhea characteristics in rats: is amylose an antidiarrheal factor?

The effectiveness of different types of rice in relation to their ability to accelerate diarrhea recovering was evaluated in a rat model of osmotic diarrhea (OD). Animals (90-100 g) received protein free diet until reaching up to 20% weight loss, followed by lactose rich diet (LRD) to induce osmotic diarrhea. Rats presenting osmotic diarrhea were divided into 4 groups, which received lactose rich diet for 4 days from 8 am to 8 pm, and one of three experimental products containing 6% rice flour differing in amylose content during the night: high (HA), intermediate (IA), and low (LA). A group fed stock diet containing equivalent amount of lactose was taken as control and allowed to recover spontaneously. Amylose and viscosity (cp at 25 °C, 10 rpm) of final products were determined. Effectiveness was expressed as the ratio between percentages of normal vs. diarrheic stools during the treatment. Fecal characteristics in this rat model improved only as result of feeding high amylose content (HA) type of rice. In this experimental model of osmotic diarrhea in young rats, the antidiarrheal effects of rice were strongly dependent on the type of diet used and appear to be related to its amylose content.

Lactose hydrolysis potential and thermal stability of commercial β-galactosidase in UHT and skimmed milk

Abstract The commercial enzyme (E.C. = 3.2.1.23) from Kluyveromyces lactis (liquid) and Aspergillus oryzae(lyophilized) was investigated for its hydrolysis potential in lactose substrate, UHT milk, and skimmed milk at different concentrations (0.7; 1.0 and 1.5%), pH values (5.0; 6.0; 6.5 and 7.0), and temperature (30; 35; 40 and 55 ºC). High hydrolysis rates were observed for the enzyme from K. lactis at pH 7.0 and 40 ºC, and from A. oryzae at pH 5.0 and 55 ºC. The enzyme from K. lactis showed significantly higher hydrolysis rates when compared to A. oryzae. The effect of temperature and β-galactosidase concentration on the lactose hydrolysis in UHT milk was higher than in skimmed milk, for all temperatures tested. With respect to the thermal stability, a decrease in hydrolysis rate was observed at pH 6.0 at 35 ºC for K. lactisenzyme, and at pH 6.0 at 55 ºC for the enzyme from A. oryzae. This study investigate the hydrolysis of β-galactosidase in UHT and skimmed milk. The knowledge about the characteristics of the β-galactosidase fromK. lactis and A. oryzae enables to use it most efficiently to control the enzyme concentration, temperature, and pH in many industrial processes and product formulations.

Lactose intolerance and cow's milk protein allergy

Abstract Adverse reactions to food intake have very diverse etiology and symptomatology. Regarding milk, its food allergy is presented as lactose intolerance, the sugar in milk, or allergy to milk protein. Despite having different symptomatology, confusions among allergic conditions to dairy and its mediators are common. Milk protein allergy originates from protein components present in milk, causing reactions to either the protein fractions in emulsion (caseins) or in whey (milk albumin). The allergic reaction is type IV mediated by T lymphocytes. The allergic reaction produces severe cellular damage and it triggers physical, mental and emotional symptomatology that may vary in time, intensity and severity. Lactose intolerance is originated by total or partial absence of the enzyme that digests this disaccharide. Lactose intolerance can be primary or congenital and secondary; the former being more rare and severe, the latter being more common. Lactase deficiency can be diagnosed by symptoms associated with cramping and diarrhea. Thus, the objective of this study was to conduct a review of available literature on cow’s milk protein allergy and lactose intolerance.

Nôvo meio para isolamento de enterobacteriáceas e diferenciação simultânea das colônias de Proteus e Providência

Um nôvo meio é proposto para o isolamento de enterobacteriáceas. Baseia-se na propriedade de desanimar a fenil-alanina que possuem tôdas as bactérias dos grupos Proteus e Providencia. As colônias dêstes microrganismos apresentam no meio descrito coloração marrom característica. As colônias das outras enterobacteriáceas, fermentadoras rápidas ou lentas e não fermentadoras da lactose, apresentam aspecto diferente.

Testagem do 1 - beta - D - Ribofuranosil, 1.2.4 - triazole - 3 - carboxamide em pacientes com hepatite

Realizou-se estudo do tipo duplo anonimato em 18 pacientes com hepatite aguda benigna. O gruoo experimental foi testado com uma provável droga de ação antiviral: 1-BETA-D-RIBOFURANOSIL, 1,2,4-TRIAZOLE-3- CARBOXAMIDE. O grupo controle ingeriu um placebo de lactose. Teve-se especial cuidado na seleção de pacientes, incluindo apenas pacientes que preenchessem critérios bem estabelecidos. Os pacientes foram seguidos semanalmente, avaliando-os clínica e laboratorialmente. Os resultados não evidenciaram diferenças significativas entre os dois grupos, sugerindo-se estudos com casuística mais numerosa e em regime de internação hospitalar.

The effects of glutamine-supplemented diet on the intestinal mucosa of the malnourished growing rat

Glutamine is the most abundant amino acid in the blood and plays a key role in the response of the small intestine to systemic injuries. Mucosal atrophy is an important phenomenon that occurs in some types of clinical injury, such as states of severe undernutrition. Glutamine has been shown to exert powerful trophic effects on the gastrointestinal mucosa after small bowel resection or transplant, radiation injury, surgical trauma, ischemic injury and administration of cytotoxic drugs. Since no study has been performed on the malnourished animal, we examined whether glutamine exerts a trophic effect on the intestinal mucosa of the malnourished growing rat. Thirty-five growing female rats (aged 21 days) were divided into 4 groups: control - chow diet; malnutrition diet; malnutrition+chow diet; and malnutrition+glutamine-enriched chow diet (2%). For the first 15 days of the experiment, animals in the test groups received a malnutrition diet, which was a lactose-enriched diet designed to induce diarrhea and malnutrition. For the next 15 days, these animals received either the lactose-enriched diet, a regular chow diet or a glutamine-enriched chow diet. After 30 days, the animals were weighed, sacrificed, and a section of the jejunum was taken and prepared for histological examination. All the animals had similar weights on day 1 of experiment, and feeding with the lactose-enriched diet promoted a significant decrease in body weight in comparison to the control group. Feeding with both experimental chow-based diets promoted significant body weight gains, although the glutamine-enriched diet was more effective. RESULTS: The morphological and morphometric analyses demonstrated that small intestinal villous height was significantly decreased in the malnourished group, and this change was partially corrected by the two types of chow-based diet. Crypt depth was significantly increased by malnutrition, and this parameter was partially corrected by the two types of chow-based diet. The glutamine-enriched diet resulted in the greatest reduction of crypt depth, and this reduction was also statistically significant when compared with control animals. CONCLUSIONS: Enteral glutamine has some positive effects on body weight gain and trophism of the jejunal mucosa in the malnourished growing rat.

Avaliação da concentração de proteínas e da atividade de α-galactosidases nos cotilédones e no eixo embrionário de sementes de Dalbergia nigra durante a germinação

Este trabalho teve como objetivos a quantificação de proteínas e da atividade da enzima α-galactosidase, no eixo embrionário e nos cotilédones, de sementes de Dalbergia nigra (jacarandá-da-bahia) durante a germinação. As sementes foram colocadas para embeber em água por sete dias, sendo retiradas amostras para a avaliação bioquímica e cinética da enzima. A atividade da enzima α-galactosidase aumenta com a embebição das sementes nos dois compartimentos, embora não esteja presente no eixo embrionário de sementes secas. A diferença na atividade da enzima entre os cotilédones e o eixo embrionário foi significativa. O pH 5,5 foi o de máxima atividade para as enzimas de ambos os compartimentos. A temperatura que mais estimulou a atividade da enzima nos cotilédones foi 50 ºC e de 50 a 60 ºC no eixo embrionário. A atividade da α-galactosidase foi inibida por β-mercaptoetanol e cobre, em ambos os compartimentos, enquanto a lactose e o cloreto de sódio estimularam a atividade tanto nos cotilédones como no eixo embrionário. Os valores de K M para enzimas do eixo embrionário e dos cotilédones foram de 0,239 e 0,228 mM, respectivamente.

Fermentação de carbohidratos por células desaccharomyces carlsbergensis adaptadas à "Emulsan Al"

Células de Saccharomyces carlsbergensis (IZ-1834) foram crescidas e adaptadas, progressivamente ao meio de caldo de cana esterilizado e contendo 0,001%, 0,002%, 0,003%, 0,004% e 0,00% de emulsan Al (v/v) além do tratamento testemunho isento de Emulsan Al. Estas células, levadas a Warburg fermentaram: glicose, rafinose. Não fermentaram: galactose, maltose e lactose. Não exibiram praticamente fermentação endógena. Glicose e caldo de cana tiveram seus rendimentos elevados, no caso das células utilizadas serem aquelas adaptadas aos diferentes teores de Emulsan Al. A fermentação da rafinose sofreu notável aceleração quando as células utilizadas foram adaptadas à Emulsan Al, sendo que a aceleração foi da ordem de 2 a 3 vêzes àquela observada no experimento com células crescidas em meio isento de Emulsan Al. A diferença da permeabilidade entre um e outro tipo de célula parece explicar o fenômeno.