Hévila Oliveira Salles

Safety, beneficial and technological properties of Enterococcus faecium isolated from Brazilian cheeses

This study aimed to characterize the safety and technological properties of Enterococcus faecium strains isolated from Brazilian Coalho cheeses. High levels of co-aggregation were observed between Enterococcus faecium strains EM485 and EM925 and both Escherichia coli and Clostridium perfringens . Both strains presented low levels of hydrophobicity. E. faecium EM485 and EM925 were both able to grow in the presence of 0.5% of the sodium salts of taurocholic acid (TC), taurodeoxycholic acid (TDC), glycocholic acid (GC), and glycodeoxycholic acid (GDC), although they showed the ability to deconjugate only GDC and TDC. Both strains showed good survival when exposed to conditions simulating the gastro intestinal tract (GIT). When tested for the presence of virulence genes, only tyrosine decarboxylase and vancomycin B generated positive PCR results.

Lectin, hemolysin and protease inhibitors in seed fractions with ovicidal activity against Haemonchus contortus

Bioactive molecules of plant species are promising alternatives for the chemical control of gastrointestinal nematodes in ruminants. Extracts of native and exotic seed species from Brazils semi-arid region were tested in vitro in an egg hatch assay and the bioactivity of their proteins was investigated. Each seed species was subjected to three extractions with three types of solvents. All the seeds showed ovicidal activity, which varied according to the solvents. Higher ovicidal activity was found in the molecule fractions of low molecular weight (<12 kDa) for Albizia lebbeck, Ipomoea asarifolia, Jatropha curcas, Libidibia ferrea, Moringa oleifera and Ricinus communis (P<0.05, Bonferroni test). The two fractions of Crotalaria spectabilis showed the same ovicidal activity (P>0.05, Bonferroni test). Hemagglutinating activity was detected in the fractions of C. spectabilis and M. oleifera fractions, hemolysin activity in the A. lebbeck and M. oleifera fractions, serine protease inhibitory activity in the A. lebbeck, I. asarifolia, J. curcas, M. oleifera and R. communis fractions, cysteine protease inhibitor activity in the M. oleifera fraction, and no protein activity in the L. ferrea fraction. The results of this work reveal new plant species with a potential for use in controlling nematode parasites in goats, thus opening a new field of research involving plant protein molecules with ovicidal properties.

Functional Properties of Lactobacillus mucosae Strains Isolated from Brazilian Goat Milk

The search for probiotic candidates among lactic acid bacteria (LAB) isolated from food may uncover new strains with promising health and technological properties. Lactobacillus mucosae strains attracted recent research attention due to their ability to adhere to intestinal mucus and to inhibit pathogens in the gastrointestinal tract, both related to a probiotic potential. Properties of interest and safety aspects of three Lb. mucosae strains (CNPC006, CNPC007, and CNPC009) isolated from goat milk were investigated employing in vitro tests. The presence of genetic factors related to bile salt hydrolase production (bsh), intestinal adhesion properties (msa, map, mub, and ef-tu), virulence, and biogenic amine production were also verified. All strains exhibited the target map, mub, and ef-tu sequences; the msa gene was detected in CNPC006 and CNPC007 strains. Some of the searched sequences for virulence factors were detected, especially in the CNPC009 strain; all strains carried the hyl gene, related to the production of hyaluronidase. Lb. mucosae CNPC007 exhibited a high survival rate in simulated gastric and enteric conditions. Besides, all strains exhibited the bsh sequence, and CNPC006 and CNPC007 were able to deconjugate salts of glycodeoxycholic acid (GDC). Regarding technological properties for dairy product applications, a relatively higher milk acidification and clotting capacity, diacetyl production, and proteolytic activity were registered for CNPC007 in comparison to the other strains. Collectively, the results aim at Lb. mucosae CNPC007 as a promising probiotic candidate for application in dairy products, deserving further studies to confirm and explore its potential.

Degradabilidade in situ do bagaço de cana-de-açúcar para pequenos ruminantes de raças naturalizadas do Nordeste brasileiro

Com o crescimento da industria sucroalcooleira, buscam-se alternativas de uso dos residuos gerados por ela. Os pequenos ruminantes de racas naturalizadas do Nordeste brasileiro mostram-se como grupos potenciais para que seja utilizado o bagaco de cana-de-acucar (BCA) nas dietas. Nesse contexto, objetivou-se determinar a degradabilidade ruminal in situ da materia seca (MS) e da fibra em detergente neutro (FDN) do BCA e os parâmetros ruminais em caprinos Moxoto e ovinos Morada Nova, fistulados no rumen. Contidos em sacos de nailon, 3g de BCA foram incubados no rumen nos tempos seis, 24 e 96 horas, determinando-se o conteudo de MS e FDN nos residuos obtidos. Nos tempos zero, seis e 12 horas apos a primeira refeicao, mediram-se no liquido ruminal pH e nitrogenio amoniacal (N-NH3) ruminal. O CMS nao diferiu entre caprinos e ovinos. O potencial de maxima degradacao da MS foi semelhante entre especies, e da FDN foi superior em caprinos. Ovinos apresentaram maiores tempo de colonizacao, taxa de degradacao e degradabilidade efetiva da MS e FDN. O pH nao diferiu entre as especies. Observou-se maior concentracao de N-NH3 ruminal em caprinos, no tempo zero. Diante da maior velocidade de degradacao da MS do BCA pelos ovinos, essa especie se mostra detentora de uma microbiota ruminal com crescimento mais eficiente sobre o BCA.

Partial purification and thermal stability of two peroxidases from Pithecellobium dulce (Roxb.) Benth. Aril.

Two peroxidase (POX) forms, named PdPI and PdPII, were partially purified from the Pithecellobium dulce aril, using ammonium sulfate precipitation and anion exchange chromatography. Zymography of the proteins obtained after precipitation in the range of 60-90% ammonium sulfate (F6090 fraction) showed two bands with peroxidase activity. In DE-52 cellulose column, the peroxidase activity was detected in unadsorbed peak (PdPI) and adsorbed peak eluted with 0.2 mol L -1 NaCl (PdPII) suggesting that PdPI (~114 kDa) and PdPII (~77 kDa) are basic and acidic proteins, respectively, being PdPI stable at 80oC. This is the first report of partial purification of POX from P. dulce aril, indicating that this species may be a new source of enzymes for use in biosensors and other biotechnological applications.