Bacteriophage amplification assay for detection of Listeria spp. using virucidal laser treatment

A protocol for the bacteriophage amplification technique was developed for quantitative detection of viable Listeria monocytogenes cells using the A511 listeriophage with plaque formation as the end-point assay. Laser and toluidine blue O (TBO) were employed as selective virucidal treatment for destruction of exogenous bacteriophage. Laser and TBO can bring a total reduction in titer phage (ca. 10(8) pfu/mL) without affecting the viability of L. monocytogenes cells. Artificially inoculated skimmed milk revealed mean populations of the bacteria as low as between 13 cfu/mL (1.11 log cfu/mL), after a 10-h assay duration. Virucidal laser treatment demonstrated better protection of Listeria cells than the other agents previously tested. The protocol was faster and easier to perform than standard procedures. This protocol constitutes an alternative for rapid, sensitive and quantitative detection of L. monocytogenes.

Efeito da Lecitina de Soja sobre os Lipídeos e Proteína C reativa e na prevenção da Hipertrofia Ventricular Esquerda de Camundongos Hiperlipidêmicos / Effect of soy lecithin on lipids and C-reactive protein and the prevention of Left Ventricular Hypertrophy in hyperlipidemic mice

A regulação do metabolismo lipídico com drogas ou alimentos naturais é um alvo importante para diminuir o risco de doenças cardiovasculares. O objetivo deste estudo foi verificar o efeito da lecitina de soja na dislipidemia e na hipertrofia ventricular de camundongos hipercolesterolêmicos. Utilizaram-se quatro grupos de camundongos LDLr-/- com 3 meses de idade que receberam a seguintes dietas: Grupo S- ração padrão; Grupo S+Lec- ração padrão e lecitina de soja; Grupo HL- ração hiperlipídica; e Grupo HL+Lec- ração hiperlipídica e lecitina de soja. Após 15 dias, o sangue foi coletado para análise sérica dos lipídeos e da proteína C reativa. O ventrículo esquerdo foi separado, a proporção peso ventricular (mg) pelo peso do animal (g) foi calculada e, em seguida, processado histologicamente. Cortes histológicos foram corados com hematoxilina/eosina e picrosírius red para avaliar alterações morfológicas e morfométricas ventriculares. A lecitina de soja apresentou efeito antidislipidêmico e aumentou os níveis séricos de HDL nos camundongos do grupo S+Lec. Entretanto, nos camundongos do grupo HL+lec, a lecitina de soja não preveniu a dislipidemia, apenas aumentou o nível sérico do HDL. Este efeito nestes animais influenciou no processo inflamatório cardiovascular, reduzindo o nível sérico de proteína C reativa; e prevenindo a hipertrofia ventricular esquerda. A utilização da lecitina de soja representa um tratamento e/ou uma prevenção alternativa de baixo custo para as dislipidemias não associadas com dieta hiperlipídica. Contudo, a lecitina de soja aumenta os níveis séricos do HDL prevenindo o desenvolvimento da HVE mesmo em dislipidemias associadas com dieta hiperlipídica.

The regulation of lipid metabolism with drugs or natural foods is an important target for reducing the risk of cardiovascular disease. The aim of this study was to investigate the effects of soy lecithin on left ventricular hypertrophy (LVH) and dyslipidemia in hypercholesterolemic mice. We used four experimental groups of LDLr-/- mice (aged 3 months), which received the following diets: Group S: standard diet, Group S+Lec: standard diet and soy lecithin; Group HL: hyperlipidic diet and Group HL+Lec: hyperlipidic diet and soy lecithin. After 15 days on these diets, blood was collected for analysis of serum lipids and C-reactive protein. The left ventricle was dissected out and weighed and the ratio of its weight to the body weight of the animal was calculated, after which it was processed histologically. Sections were stained with hematoxylin-eosin and picrosirius red, to assess morphological and morphometric changes in the ventricle. In Group S+Lec, the soy lecithin had an antidyslipidemic effect and enhanced the serum levels of HDL. However, in the mice in group HL+Lec, soy lecithin did not prevent dyslipidemia, only increasing the serum level of HDL. These effects in these animals influenced the cardiovascular inflammatory process, reducing the level of serum C-reactive protein and preventing LVH. Soy lecithin could thus be used as a treatment or a low-cost alternative preventative measure against dyslipidemia associated with a non-fat diet. However, soy lecithin increases the serum level of HDL, reducing the risk of LVH even in dyslipidemia associated with a high-fat diet.

Freqüência de anemia infecciosa em eqüinos no Acre, 1986 a 1996 / Frequency of equine infectious anemia in the State of Acre, Brazil, from 1986 to 1996

Foram analisadas as fichas de 9.963 eqüídeos do Acre, submetidos ao teste de imunodifusäo em gel de ágar (IDGA) para anemia infecciosa eqüina (AIE), no período de 1986 a 1996. As regiöes sócio-ecológicas da Bacia do Alto Juruá, Alto Acre e Alta Bacia do Purus apresentaram os maiores índices da doença, o que caracteriza a associaçäo entre regiäo e positividade. Essas áreas säo fronteiriças com o Peru, Bolívia e o Estado do Amazonas, säo distantes de Rio Branco, capital do Estado, onde muitas vezes é difícil o acesso pelas estradas, revelando serem áreas de risco. As regiöes Oriental e Rio Branco apresentaram baixos índices de positividade. Näo se observou diferença estatística entre animais positivos e negativos quanto à espécie, sexo, raça e idade

Metabolite and light regulation of metabolism in plants: lessons from the study of a single biochemical pathway

We are using molecular, biochemical, and genetic approaches to study the structural and regulatory genes controlling the assimilation of inorganic nitrogen into the amino acids glutamine, glutamate, aspartate and asparagine. These amino acids serve as the principal nitrogen-transport amino acids in most crop and higher plants including Arabidopsis thaliana. We have begun to investigate the regulatory mechanisms controlling nitrogen assimilation into these amino acids in plants using molecular and genetic approaches in Arabidopsis. The synthesis of the amide amino acids glutamine and asparagine is subject to tight regulation in response to environmental factors such as light and to metabolic factors such as sucrose and amino acids. For instance, light induces the expression of glutamine synthetase (GLN2) and represses expression of asparagine synthetase (ASN1) genes. This reciprocal regulation of GLN2 and ASN1 genes by light is reflected at the level of transcription and at the level of glutamine and asparagine biosynthesis. Moreover, we have shown that the regulation of these genes is also reciprocally controlled by both organic nitrogen and carbon metabolites. We have recently used a reverse genetic approach to study putative components of such metabolic sensing mechanisms in plants that may be conserved in evolution. These components include an Arabidopsis homolog for a glutamate receptor gene originally found in animal systems and a plant PII gene, which is a homolog of a component of the bacterial Ntr system. Based on our observations on the biology of both structural and regulatory genes of the nitrogen assimilatory pathway, we have developed a model for metabolic control of the genes involved in the nitrogen assimilatory pathway in plants