MOSP - Macao Scientific Publishers

文章

Aflatoxin contamination of foods in developing countries: Implications for hepatocellular carcinoma and chemopreventive strategies

E. Olatunde Farombi*

Abstract: Hepatocellular carcinoma (HCC) is the fifth leading cause of cancer mortality in the world and, in certain parts of Asia and Africa, it accounts for about 70% of cancer deaths. Chronic hepatitis B virus (HBV) infection and dietary exposure to aflatoxin B1 (AFB 1) are the two major risk factors in multi factorial aetiology of HCC. Multiple lines of evidence indicate synergistic interaction between these two agents in the development of HCC. Several mechanisms of interaction have been suggested including activation of cytochrome P450s by HBV infection leading to the metabolism of inactive AFB1 to the mutagenic AFB 1-8,9-epoxide as well as the generation of reactive oxygen species by HBV and AFB1 sensitising the cells to AFB1-induced p53 249ser mutations. The poor survival rate achieved by the current surgical procedures and chemotherapy treatment has motivated a number of scientific investigations to elucidating the molecular events involved in HCC thus providing the scientific rationale for prevention strategies, including primary and chemoprevention approaches. Recent findings have implicated intracellular signalling cascades involving nuclear factor kappa B (NF-kB) and nuclear transcription factor erythroid 2p45 (NF-E2)-related factor 2 (Nrf2) as molecular targets of a wide range of chemopreventive agents. The new findings thus raise the intriguing possibility that chemopreventives modulating these molecular targets in the liver might provide a novel therapeutic approach to the development of liver cancer.[...] Read More.

Keywords: Hepatocellular carcinoma, chronic hepatitis B virus, aflatoxin B1, chemoprevention.

Full text

Download：791

文章

Identification of metallo-lactamase from a clinical isolate at Saint Camillle medical Center of Ouagadougou, Burkina Faso

Identification of metallo-b-lactamase from a clinical isolate at Saint Camillle medical Center of Ouagadougou, Burkina Faso

Abstract: A metallo-b-lactamase was identified from a clinical sample. The host bacteria was identified to be Chryseobacterium indologenes. This preliminary characterization of the enzyme is reported here.[...] Read More.

Keywords:

Full text

Download：773

文章

Studies on the extraction and characterization of thermostable ï¡-amylase from pericarp of Borassus indica

Studies on the extraction and characterization of thermostable a-amylase from pericarp of Borassus indica

Abstract: Thermostable a-amylase was extracted and characterized from the fruits (pericarp) of Borassus indica. Analysis on the influence of various physico-chemical parameters on the extracted enzyme revealed a Vmax of 0.793 and a Km of 0.022. The optimum temperature was found to be 370C at pH 4.5. The stability studies on enzyme activity envisaged that the enzyme is stable up to 800C and retained its activity over a wide range of pH (4.0 – 8.5). Significant enhancement in the enzyme activity was observed in the presence of metal ions like Manganese and Strontium and an insignificant decrement in the presence of Sodium ions.[...] Read More.

Keywords: a-Amylase, Borassus indica, enzyme activity.

Full text

Download：794

文章

Temperature effect on dextransucrase production by Leuconostoc mesenteroides FT 045 B isolated from Alcohol and Sugar Mill Plant

Mariana CORTEZI, Rubens MONTI and Jonas CONTIERO*

Abstract: Temperature (23 to 31°C) and sucrose concentration (3 and 4%) effects on dextransucrase production by Leuconostoc mesenteroides NRRL B 512 (F) and Leuconostoc mesenteroides FT 045 B were studied. The conditions in all fermentations were: total reaction volume 2 L, 132 rev. min-1, 0.5 vvm and pH 6.0. The optimum temperature for enzyme yield for strain NRRL B 512 (F) was 23°C, where at 8-h fermentation was possible to achieve 49.3 DSU/mL. When FT 045 B strain was utilized, 3.2 DSU/mL was obtained at temperature 23 to 25 °C.[...] Read More.

Keywords: Dextran, dextransucrase, Leuconostoc mesenteroides NRRL B512 (F), Leuconostoc mesenteroides FT045 B, temperature, enzyme activity.

Full text

Download：808

文章

Methods of preparation and nutritional evaluation of dishes consumed in a malaria endemic zone in Cameroon (Ngali II)

Roger PONKA*, Elie FOKOU, Rose LEKE, Martin FOTSO, Jacob SOUOPGUI, Mercy ACHU BIH and Félicité MBIAPO TCHOUANGUEP

Abstract: This study deals with the description of the methods of preparation and determination of the nutritional potential of dishes consumed by Cameroonians living in a rural area, which is a malaria endemic zone, called Ngali II. The dishes consumed are prepared from leguminous seeds, seeds of the Cucurbitaceae family (egusi seeds), green leafy vegetables, tubers, cereals unripe bananas and plantains. The contents in moisture, ash, proteins, lipids, crude fibres and carbohydrates were determined by standard AOAC methods. The results obtained are expressed in percentage f.w for moisture and percentage d.w for ash, proteins, lipids, crude fibres and carbohydrates. The moisture content ranges from 57.77-86.17; ash, 0.66-14.74; proteins, 1.49-37.25; lipids, 0.26-54.98; crude fibres, 1.43-17.82 and carbohydrates, 3.51-95.76. This study revealed that a higher consumption of dishes made from leguminous seeds, egusi seeds, green leafy vegetables, and low consumption of tubers, unripe bananas and plantains will lead to a good nutritional balance. Keywords: Dishes, preparation, nutritional potential, malaria.[...] Read More.

Keywords: Dishes, preparation, nutritional potential, malaria.

Full text

Download：798

文章

Increase of nisin production by Lactococcus lactis in different media

Angela Faustino Jozala, Letícia Célia de Lencastre Novaes, Olivia Cholewa, Dante Moraes, Thereza Christina Vessoni Penna*

Abstract: Nisin production related to the growth conditions of Lactococcus lactis subsp. lactis ATCC 11454, the effects of various media components and concomitant release of nisin into the media, were studied through transfers (five times). Nisin production was assayed by agar diffusion using Lactobacillus sake ATCC 15521 as the sensitive test organism. The expression of nisin was strongly influenced by the addition of skimmed milk to both MRS and M17 broth, with the highest production obtained after the second and the fifth transfers, respectively, with maximum expression after 36 h of incubation.[...] Read More.

Keywords: Nisin, Lactococcus lactis, Lactobacillus sake, bacteriocin, milk.

Full text

Download：757

文章

Activity of essential oil and phenolic acid extracts of pepperfruit (Dennetia tripetala G. Barker; Anonaceae) against some food-borne microorganisms

B. O. Ejechi* and D. E. Akpomedaye

Abstract: A previous report showed that the essential oil and phenolic acid extracts of pepperfruit (Dennetia tripetala) inhibited the growth of tomato-rot fungi. The study was subsequently extended to other food-borne microorganisms (Staphylococcus aureus, Salmonella sp. Pseudomonas aeruginosa., Proteus sp., Escherichia coli., Enterococcus faecalis., Serratia sp., Bacillus sp., Clostridium sp., Penicillium sp., Aspergillus flavus) isolated from food products. All the isolates were susceptible to the extracts with a minimum inhibitory concentration (MIC) range of 1.0-4.0 mg/ml. The essential oil inhibited the food-borne organisms better (MIC: 1.0-2.5) than the phenolic acid (MIC: 1.5-4.0). The challenge organisms in fresh, boiled or roasted beef, treated with the extracts were either not detected, declined significantly in number (p0.05) after 7 days. A role for pepperfruit extracts in natural food protection is further indicated.[...] Read More.

Keywords: Essential oil, pepperfruit, dennetia tripetala, phenolic acid, food-borne microorganisms.

Full text

Download：827

文章

Isolation and Identification of a Brevibacterium linens strain degrading p-nitrophenol

Debananda Ningthoujam

Abstract: A bacterium was isolated from garden soil in basal salts medium containing p-nitrophenol (PNP). Subsequent subcultures in basal salts agar, nutrient agar plates and agar slants by streaking led to isolation of pure colonies. The pure culture could degrade up to 300 mg/L PNP in presence of yeast extract. It was Gram positive rods, mostly single, catalase-positive, hydrolyzing strach and casein but not urea. Gelatin liquefaction was positive whereas acid production from carbohydrates was negative. It showed tyrosine clearing and had meso-DAP as the characteristic cell wall amino acid. On the basis of the morphological, physiological, and biochemical tests the organism was identified as Brevibacterium linens. To our knowledge, this is the first report of any Brevibacterium strain able to degrade PNP.[...] Read More.

Keywords: p-Nitrophenol, nitroaromatics, (bio) degradation, isolation, Brevibacterium.

Full text

Download：800

文章

Effect of cultural conditions on xylanase production by Streptomyces sp. (strain Ib 24D) and its potential to utilize tomato pomace

Rifaat Rawashdeh, Ismail Saadoun* and Amjad Mahasneh

Abstract: The purpose of this study was to determine the effect of some cultural conditions on the xylanase enzyme production by Streptomyces sp. (strain Ib 24D) and to investigate its potential to produce xylanase utilizing tomato pomace as a substrate. Xylanase activity was detected using the dinitrosalicylic acid assay method. The crude enzyme was maximally active at pH 6.5 and 60°C. The maximal enzyme production was obtained when oat spelt xylan was used as a carbon source. When tomato pomace was used as carbon and nitrogen source, the maximal xylanase production was 1447 U/ml. SDS-PAGE and zymogram analysis revealed one band of 58 kDa with xylanolytic activity. The Streptomyces sp . (strain Ib 24D) was able to produce a considerable amount of xylanase with high levels of activity at a broad ranges of pH and temperature, in addition to its ability to utilize tomato pomace as a carbon and a nitrogen source.[...] Read More.

Keywords: Agricultural wastes, biodegradation, Streptomyces sp., xylanase.

Full text

Download：814

文章

Quantitative trait loci for head-bug resistance in sorghum

M. Deu, A. Ratnadass*, M. A. Hamada, J.L. Noyer, M. Diabate† & J. Chantereau

Abstract: QTLs were mapped in F2 progeny derived from a cross between the head-bug resistant sorghum cultivar Malisor 84- 7 and susceptible S 34. The phenotypic evaluation was conducted in Mali. The mapped population consisted of 217 F2 plants, with 345 homologous and heterologous RFLP probes and 49 microsatellite markers tested. Eighty-one RFLP markers revealed polymorphism between the two parents, and 14 microsatellite markers gave usable amplification products. A genetic map including 92 loci distributed over 13 linkage groups, and covering a total distance of 1160 cM was built. Three significant and seven putative QTLs were detected and placed on the map.[...] Read More.

Keywords: Head-bug, Eurystylus oldi, sorghum, resistance, RFLP, microsatellite, QTL.

Full text

Download：762

Search Filter