MOSP - Macao Scientific Publishers

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Aflatoxin control and prevention strategies in key crops of Sub-Saharan Africa

Kerstin Hell* and Charity Mutegi

Abstract: Aflatoxins are secondary fungal metabolites that contaminate agricultural commodities and can cause sickness or death in humans and animals. Risk of aflatoxin contamination of food and feed in Africa is increased due to environmental, agronomic and socio-economic factors. Environmental conditions especially high humidity and temperature favour fungal proliferation, but also drought conditions increase risk of aflatoxin contamination. Low-input farming practices compound fungal and aflatoxin contamination of crops. The socio-economic and food security status of the majority of inhabitants of sub-Saharan Africa leaves them few options for choosing low-risk and high quality products. Several technologies have been tested in Africa to reduce aflatoxin risk. Field management practices that increase yields can reduce the risk of aflatoxin development. They include use of resistant varieties, crop rotation, well-timed planting, weed control, pest control especially control of insect pests and avoiding drought and nutritional stress through fertilization and irrigation. Measures to stop the infection process by controlling the aflatoxin causing fungi in the field are achieved through use of pesticides and atoxigenic fungi to competitively displace toxigenic fungi, and timely harvest. Post-harvest interventions that reduce aflatoxin include rapid and proper drying, proper transportation and packaging, sorting, cleaning, drying, smoking, post harvest insect control, and the use of botanicals or synthetic pesticides as storage protectants. Another approach is to reduce the frequent consumption of ‘high risk’ foods (especially maize and groundnut) by consuming a more varied diet, and diversifying the diet into less risky staples like sorghum and millet. Chemo-preventive measures that can reduce aflatoxin effect include daily consumption of chlorophyllin or oltipraz and incorporating hydrated sodium calcium alumino-silicates into the diet. Reduction and detoxification of aflatoxin is often achieved physically (sorting, physical segregation, flotation etc.), chemically (e.g. calcium hydroxide, ammonia) and microbiologically by incorporating pro-biotics or lactic acid bacteria into the diet. Millers can use blending of less and more contaminated products to reduce the overall risk. There is need for efficient monitoring and surveillance with cost-effective sampling and analytical methods to reduce risk in Africa. Public education and awareness can sensitize the population on aflatoxin risk and its management.[...] Read More.

Keywords: Aflatoxin, Sub-Saharan Africa, control measures.

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Microbiological investigation of stool in patients with acute diarrhea

Turan Gunduz, Sedat Cumen, Ali Ari, M. Mete Demirel, Serdag Etiz and Ziya Tay

Abstract: Acute gastroenteritis is an important health public issue especially in developing countries. The aim of this study was to determine the most common microbial agents responsible for acute diarrheas in our city. The study was performed prospectively between December 2005 and January 2006 in Manisa, Turkey. Stool samples were collected from patients with acute diarrhea who attended to different hospitals of the city (University Hospital, Government Hospitals, Pediatrics Hospital and Health Public Laboratory). The stool samples of 300 patients (50 children, 250 adults) were investigated. Standard cultivation methods were performed to determine Salmonella ve Shigella spp. Escherichia coli 0157:H7 was tested by ImmunoCard STAT! E. coli 0157 Plus. The strains that were identified as sorbitol negative E. coli were investigated by E. coli 0157: H7 antiserum. The isolated microorganisms were as follows: Salmonella spp. 7 (2.3%), Shigella spp. 5 (1.6%), Giardia intestinalis 12 (4%), Enterobius vermicularis 5 (1.6%), Rotavirus 2 (0.6%) and sorbitol negative E. coli 18 (6%). Only one Sorbitol negative E. coli colony showed agglutination with E. coli 0157:H7 antiserum.The most common pathogens were identified as G. intestinalis in children and E. coli in adults. Sorbitol negative E. coli were isolated in 18 of the stool samples, and only one of them showed agglutination with E. coli 0157:H7. Although rare, this strain may lead serious complications and it should be kept in mind in patients with acute diarrhea.[...] Read More.

Keywords: Escherichia coli 0157, diarrhea, Salmonella spp., Shigella spp., Giardia intestinalis.

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Isolation and identification of some fruit spoilage fungi: Screening of plant cell wall degrading enzymes

Full Length Research Paper

Abstract: This study investigates the current spoilage fruit fungi and their plant cell wall degrading enzymes of various fresh postharvest fruits sold in Jeddah city and share in establishment of a fungal profile of fruits. Ten fruit spoilage fungi were isolated and identified as follows Fusarium oxysporum (banana and grape), Aspergillus japonicus (pokhara and apricot), Aspergillus oryzae (orange), Aspergillus awamori (lemon), Aspergillus phoenicis (tomato), Aspergillus tubingensis (peach), Aspergillus niger (apple), Aspergillus flavus (mango), Aspergillus foetidus (kiwi) and Rhizopus stolonifer (date). The plant cell wall degrading enzymes xylanase, polygalacturonase, cellulase and -amylase were screened in the cell-free broth of all tested fungi cultured on their fruit peels and potato dextrose broth (PDB) as media. Xylanase and polygalacturonase had the highest level contents as compared to the cellulase and - amylase. In conclusion, Aspergillus spp. are widespread and the fungal polygalacturonases and xylanses are the main enzymes responsible for the spoilage of fruits.[...] Read More.

Keywords: Aspergillus, Fusarium, Rhizopus, fruits, xylanase, polygalacturonase.

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Evaluation of methicillin resistance Staphylococcus aureus isolated from patients in Golestan province-north of Iran

Hamid Vaez, Alijan Tabaraei, Abdolvahab Moradi and Ezzat A. Ghaemi*

Abstract: Methicillin resistant Staphylococcus aureus (MRSA) is a main cause of nosocomial infections with consequence of increasing hospitalization, costs of treatment and rate of mortality. This study was aimed to demonstrate distribution of MRSA strains and their antibiotic resistance pattern. In this descriptive study, 185 clinical isolates of S. aureus that were collected from different infections during September 2008 to 2009 were tested by polymerase chain reaction (PCR) and micro dilution broth. All the MRSA and methicillin sensitive Staphylococcus aureus (MSSA) isolates were tested for antibiotic resistance pattern by disk diffusion method with 14 different antibiotics. Data were entered in SPSS software version 16 and analyzed by chi-square test. P value of 8 µg/ml were mecA positive. MRSA is spreading worldwide with increasing levels of resistance, and accurate and early detection of these strains is encouraged.[...] Read More.

Keywords: Staphylococcus aureus, methicillin resistant Staphylococcus aureus, methicillin sensitive Staphylococcus aureus, minimum inhibitory concentration, mecA

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A study of various biological wastewater treatment processes

AYANDA Olushola Sunday* and AKINSOJI Olatunbosun Seun

Abstract: Nitrification is an important biological process in nitrogen cycling and has a significant effect on effluent quality in wastewater treatment. Nitrification occurs in two steps by two types of chemoautotrophic bacteria, the ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). The ammonia oxidizing bacteria is responsible for the oxidation of ammonia with oxygen into nitrite and is often the rate-limiting step in nitrification in wastewater treatment plants. Hence, a better understanding of the ecology, microbiology and chemistry of ammonia oxidizing bacteria in biological wastewater treatment systems is necessary in order to enhance treatment performance and control. A detailed review of various biological wastewater treatment processes, ammonia oxidizing bacteria and archaea; economic importance, problems, various molecular techniques for the investigation of the diversity and community structure, as well as the isolation of ammonia oxidizing bacteria were discussed.[...] Read More.

Keywords: Wastewater, activated sludge process, nitrification, ammonia oxidizing bacteria, ammonia oxidizing archaea, nitrite oxidizing bacteria, PCR primers.

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Assessment of the H9N2 virus spreading in various organs of the infected SPF chickens at different days after inoculation

Somayeh Asadzadeh Manjili, Iradj sohrabi Haghdoost, Pejman Mortazavi, Hamid Habibi, Hadi lashini and Esmaeil Saberfar*

Abstract: H9N2 Avian influenza virus (AVI) infection is a major cause of economic losses in poultry industry. Therefore further study to explain the virus pathogenesis is necessary. In this study tissue tropism and dissemination of A/chicken/Iran/11T/99(H9N2) virus in various organs of specific pathogen free (SPF) chickens were investigated. Fifty 2-week-old chickens hatched from SPF eggs were divided randomly into two groups. Forty chicks in the experimental and ten chicks in the control group. Experimental chicks were inoculated intranasally-intraorally with the virus. Samples of lung, trachea, pancreas, thymus, spleen, brain, bursa of fabricius, proventriclus, cloaca and kidney were aseptically collected at 1, 3, 5, 7, 9 and 10 day post inoculation (DPI). A reverse transcriptase polymerase chain Reaction (RT-PCR) test was performed for virus detection. Viral RNA was detected in the respiratory system on days 3, 5 and 7 PI. The virus was also found in the kidney on days 3,5,7,9 PI and in the pancreas on days 3 and 5 PI. Viral RNA was observed only on day 5 PI in cloaca. The virus was not detected in the blood, brain and immune system. The virus was not found from any organs on day 10 PI. These results suggest that H9N2 AIV has tropism for respiratory, digestive and urinary system following intranasal/intraoral inoculation.[...] Read More.

Keywords: Avian influenza, H9N2, SPF, RT-PCR.

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Assessment of the ahyI gene affected biofilm formation, motility, extracellular virulence and the pathogenicity in a fish model of infection

Weihua Chu*, Yan Jiang, Liu Yongwang and Wei Zhu

Abstract: Aeromonas hydrophila is a pathogen that causes disease in a wide range of homeothermic and poikilothermic hosts due to its multifactorial virulence. The production of many of these virulence determinants is associated with high cell density, a phenomenon that might be regulated by quorum sensing. The quorum sensing system regulates the expression of several virulence factors in a wide variety of pathogenic bacteria. To investigate the pathogenic role of quorum sensing system in A. hydrophila, We constructed an ahyI mutant strain of a fish-clinical isolate YJ-1, named YJ-1∆AhyI. Compared with the wild-type strain, the ahyI mutant strain exhibited a significant decrease of total extracellular virulent activity, and decreased in biofilm formation, intraperitoneal LD50 of YJ-1∆AhyI were more than 109 CFU, about 104 times higher than the parent strain. These results suggest that A. hydrophila is able to regulate its extracellular virulent factors and biofilm formation by quorum sensing systems, and indicate that disruption of quorum sensing could be a good alternative strategy to combat infections caused by A. hydrophila.[...] Read More.

Keywords: Aeromonas hydrophila, quorum sensing, biofilm, virulence factors.

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Identification of a potent antiviral terpenes and coumarins from Tunisian caprifig latex, Jrani variety

Houda LAZREG AREF*, Mahjoub AOUNI, Jean Pierre CHAUMON, Khaled SAID and Abdelwaheb FEKIH

Abstract: The aim of this study was to search for new antiviral agents from Tunisian Jrani caprifig latex (Ficus carica L., Moraceae). Terpenes and coumarins were identified by gas chromatography–mass spectrometry (GC-MS) analysis in hexane and hexane ethyl-acetate (1:1, v/v) extracts, and used in experiments to test their influence on a series of viruses, namely Herpes simplex (HSV-1), Adenovirus (ADV) and Echovirus type 11 (ECV-11). To evaluate the capacity of the extracts inhibition of viruses replication cycles by preventing their adsorption and their penetrations in the cells (by interaction with the cellular receivers designed for these viruses) or by inhibition of their intracellular replication or by virus inhibition after a direct contact under microscopic observation of cytopathic effect (CPE). Extracts inhibited virus multiplication in tested techniques at the concentrations of 19.5 and 39 µg/ml, respectively. All extracts had no cytotoxic effect on Vero cells at all tested concentrations. In conclusion, some compounds of Jrani latex which possess antiviral activities may be due to the high level of Triterpens. Their mode of action against the tested viruses was found to be at all stages of multiplication, suggesting the potential use of this compound for treatment of the infection caused by these viruses.[...] Read More.

Keywords: Ficus carica, caprifig, latex, HSV-1, HSV-2, ECV-11, ADV, coumarins, terpens.

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Gamma irradiation mediated agriculture

Issa. Piri, Mehdi. Babayan*, Abolfazl. Tavassoli and Mehdi. Javaheri

Abstract: Lately, radiation technology is widely used to produce changes in the product characteristics leading to the development of new products. Gamma irradiation is capable of hydrolyzing chemical bonds, thereby cleaving large molecules of starch into smaller fragments of dextrin that may be either electrically charged or uncharged as free radicals. These changes may affect the physical and rheological properties of irradiated foods, resulting in increased solubility of starch, decreased swelling power, and decreased viscosity of starch paste. Irradiation of gamma rays on bud wood can produce higher frequencies of mutation, leading to the creation of new variants compared to the control. Macronutrients (carbohydrates, proteins and lipids) content are relatively stable against irradiation doses up to 10 kGy, on the other hand, gamma irradiation affects proteins by causing conformational changes, oxidation of amino acids, rupturing of covalent bonds and formation of protein free radicals. Radiation mediated morphological, structural and functional changes in a plant are governed by the intensity and duration of the gamma irradiation.[...] Read More.

Keywords: Irradiation, Foods sterilized, Mutation, Biochemical change, Agriculture.

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Significance and use of walnut, Juglans regia Linn: A review

Nael Abu Taha and Mohammed A. Al-wadaan

Abstract: Juglans regia Linn is a medicinal plant that has been widely used in traditional medicine for a wide array of ailments that include helminthiasis, diarrhea, sinusitis, stomachache, arthritis, asthma, eczema, scrofula, skin disorders, and various endocrine diseases such as diabetes mellitus, anorexia, thyroid dysfunctions, cancer and infectious diseases. The present review, attempts to provide comprehensive information on the ethnobotanical use, pharmacology, nutritional value, preclinical and clinical studies, toxicity, other uses and current research prospects of the Juglans regia L. Currently, there is a renewed interest in walnut, and several investigations aimed at scientific validation of its traditional uses and a humble scientific investigation aimed at isolation and identification of active constituents of crude extracts.[...] Read More.

Keywords: Juglans regia, nutritional value, bioactivity, clinical trial, traditional use, toxicity.

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