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Emma Wanjiru Gachomo, Olusola Olusoji Shonukan and Simeon Oloni Kotchoni *
Abstract: Interactions between disease resistance (R) genes in plants and their corresponding pathogen avirulence (Avr) genes are the key determinants of whether a plant is susceptible or resistance to a pathogen attack. Evidence has emerged that these gene-for -gene interactions in the perception of pathogenic invasions and development of acquired resistance in plants involve different molecular and hormonal transduction pathways, which are still poorly understood. It has become apparent that plants actively produce several phytohormones such as ethylene, jasmonate, salicylic acid, and reactive oxygen intermediates prior to upregulation of R genes. The physiological role of these molecules in plant resistance to pathogens is beginning to attract attention. The use of transgenic plants in recent attempts, including development of mutants with altered R genes, has provided new insights into the mechanisms involved in pathogen perception, signal transduction and subsequent resistance to disease in plants. This review tries to summarize current knowledge of pathogen-related genes in plants, and how they can be use to improve disease resistance in agronomically valuable plants. It also describes the molecular basis of defense mechanisms in plants under pathogen attack.[...] Read More.
Keywords: Avr, resistance gene, hypersensitivity, pathogenesis-related proteins, transgenic, plant-defense.
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文章
N. A. Amusa*, O. A. Ashaye, M. O. Oladapo and O.O. Kafaru
Abstract: The etiology of pre-harvest deterioration of Soursop (Annona muricata) fruit in Ibadan, southwestern Nigeria and the effects on its nutrient composition was investigated. Four fungal pathogens including Botryodiplodia theobromae, Fusarium sp., Rhizopus stolonifer and Aspergillus niger were found associated with the pre-harvest deteriorating soursop . B. theobromae was the most prevalent and the most pathogenic inducing rot of 75 mm in diameter within four days of inoculation. There was a remarkable reduction in carbohydrate and protein contents of the fungal infected fruits while all other nutrients and mineral assayed were higher in the infected fruits than the non-infected ones.[...] Read More.
Keywords: Annona muricata, fungal pathogens, pre-harvest deterioration.
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Desouky Abd-El-Haleem*, Usama Beshay, Abdu O. Abdelhamid, Hassan Moawad and Sahar Zaki
Abstract: Using Ca-alginate immobilized cells of Acinetobacter sp. strain W-17, the effects of ammonium-N and nitrate- N on the biodegradation of phenol were investigated. Degradation experiments in three different culture media; minimal salts medium (MSM), simulated (SW) and modified simulated wastewater (MSW) were performed. With the freely suspended cells (cell dry weight 0.2 g/l), complete phenol (500 mg/l) degradation was achieved after incubation for 120 h. Using the immobilized cells, the time was reduced to 24 h in MSM medium, and 15 h in the MSW. The results also indicate that strain W-17 can tolerate to high concentrations of NH4+-N (63 mg/l) and NO3--N (1000 mg/l) without a significant loss in the phenol biodegradation rate. Moreover, the presence of 500 mg/l phenol in the MSW had no considerable effect on the removal of both ammonium-N and nitrate-N. Repeated use of immobilized cells revealed that they could be used as much as five times without loss of activity. Our findings could be extended to enhance biotreatment of phenol contamination in a variety of biological treatment processes.[...] Read More.
Keywords: Phenol, biodegradation, immobilization, Acinetobacter, Ca-alginate, ammonium, nitrate.
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Nyerhovwo J. Tonukari , *, John S. Scott-Craig and Jonathan D. Walton
Abstract: The expression of four Cochliobolus carbonum endo-1,4- -xylanase genes (XYL1, XYL2, XYL3, XYL4), and an exo-1,4- -xylosidase gene (XYP1) was studied following the growth of the fungus in minimal medium containing glucose, sucrose, xylose, xylan, pectin, or cellulose. The XYL1 and XYL2 genes were expressed only when the culture medium contained xylan or cellulose. Both XYL3 and XYL4 are induced by xylose and xylan, and XYP1 expression is induced by xylose, xylan, pectin and cellulose. None of these genes is expressed in glucose or sucrose media. The differential expression of these enzymes may provide means for the fungus to adapt to different conditions.[...] Read More.
Keywords: Cell wall degrading enzymes, Cochliobolus carbonum, xylan, xylanase.
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文章
J. Abiodun Elegbede* and Michael N. Gould
Abstract: Perillyl alcohol and d-limonene are naturally occurring plant compounds that exhibited anti-carcinogenic activities in mammary tumor models. The effects of these monoterpenes at the initiation stage of aflatoxin B1-induced hepatocarcinogenesis were investigated. Male F344 rats were fed Control or treatment diets throughout the study and exposed to aflatoxin for 5 days. Three days after the last aflatoxin dose, blood and liver samples were obtained. Analysis of liver samples showed that both limonene and perillyl alcohol significantly inhibited (p[...] Read More.
Keywords: Aflatoxin B1, hepatocarcinogenesis, monoterpenes, chemoprevention.
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Sagadevan G Mundree *, Bienyameen Baker, Shaheen Mowla, Shaun Peters, Saberi Marais, Clare Vander Willigen, Kershini Govender, Alice Maredza, Samson Muyanga, Jill M Farrant and Jennifer A Thomson
Abstract: Water is a major limiting factor in world agriculture. In general, most crop plants are highly sensitive to even a mild dehydration stress. There are however, a few genera of plants unique to Southern Africa, called “resurrection plants” which can tolerate extreme water loss or desiccation. We have used Xerophyta viscosa, a representative of the monocotyledonous resurrection plants to isolate genes that are associated with osmotic stress tolerance. Several genes that are differentially expressed, and that confer functional sufficiency to osmotically-stressed Escherichia coli are being studied at the molecular and biochemical levels. In this review, we use this as a basis to discuss the physiological and molecular insights into drought tolerance.[...] Read More.
Keywords: Drought stress, reactive oxygen species, osmoprotectants, abscisic acid, transcription factors.
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Ayobola A Iyanda
Abstract: Trace elements are essential micronutrients required in minute amount by a number of metabolic processes. In many parts of Africa, kerosene is widely available since it is the most commonly used fuel for cooking purposes. As a result of this common availability, excessive exposure to this product has been described. The aim of this study is to identify if exposure to trace amount of kerosene is capable of causing depletion in magnesium and trace element levels. Eighteen Wistar rats divided equally into three groups were used for the study. Administration of trace amount of kerosene (0.4 ml/kg body weight) by oral or dermal route resulted in significant increase (p[...] Read More.
Keywords: kerosene; magnesium, trace elements
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Adediran Olufemi Sola, Okpara Ihunanya Chinyere*, Adeniyi Olasupo Stephen, Jimoh Ahmed Kayode
Abstract: There is a global rise in the prevalence of obesity in both developed and developing countries reaching epidemic levels. It has therefore become an important health issue globally. This study aims at determining the prevalence of obesity in an urban and rural area in the Federal Capital Territory (FCT) Abuja – Nigeria. In a cross sectional community based study, and by a stratified random sampling method, 229 subjects were selected. A pretested structured questionnaire was administered to obtain sociodemographic characteristics. Anthropometric data were measured by standard methods. The body mass index (BMI) was calculated and in conjunction with waist WC were used as measures of obesity. The overall prevalence of obesity was 22.3%. Prevalence rates were higher in the urban area than rural area (40.7% versus 4.3%, χ2 =43.81,p[...] Read More.
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Eric Nagaonlé Somé*, Issaka Zongo, Félicité Nana, Daouda Sané, Maxime Drabo, Roger Sombié
Abstract: In Burkina Faso, the prevalence of HBs antigen is estimated at 9.1%. We aimed to describe the therapeutic and evolutionary aspects of chronic HBeAg-negative viral hepatitis B outpatients at the University Hospital Yalgado Ouédraogo. Methods: It was a cross-sectional descriptive study including 325 participants with a retrospective data collection from January 2004 to April 2016. Results: The mean age was 38.7 years and the sex ratio, 1.5. The mean concentration of HBsAg and HBV Viral load was 7861.6 IU/mL and 32 237.20 IU/mL, respectively. A total of 84 participants were on antiviral therapy; 73 (86.9%) and six (7.1%) patients were on tenofovir and lamivudine, respectively. Under tenofovir, the virological response was complete and ALT was normal in 44.4% and 77.7% of the patients after one year. HBV DNA was undetectable and ALT normal under Lamivudine in 50% of the patients after four years. The adherence to the treatment was high, moderate or low in 71.4%, 21.4% and 7.2% of the cases, respectively. In high adherent group, HBV DNA was undetectable and ALT normal in 91.6% and 95% of cases, respectively. Under tenofovir and lamivudine, we noted an HBsAg seroconversion after 2 and seven years of treatment, respectively. CONCLUSION: The prevalence of chronic HBeAg negative hepatitis B patients is currently increasing. The HBs seroconversion is still low. The sensitization of the population to avoid the viral hepatitis infection mainly by a systematic immunization of the population remains the most effective weapon to fight this disease.[...] Read More.
Keywords: hepatitis B infection, HBs antigen, HBe antigen, antiviral treatment, adherence, sub Saharan Africa.
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文章
Alka Bhatia*, Yashwant kumar and Anjali Solanki Kathpalia
Abstract: Granulomatous inflammation is considered to be an immune mechanism against infections or certain non-neoplastic conditions. Rarely granuloma formation may be noted in neoplastic disorders also. However a granulomatous response in the lymph nodes draining cancers is unusual. Such granulomas may sometimes show tumour cells in their centre. The exact cause of this phenomenon is not known but an immunologic reaction to tumour antigens has been suggested. A close scrutiny of such granuloma is necessary to avoid under diagnosis of a metastatic disease. Subtle morphological fea-tures which may be helpful in differentiating a co-existing infection or tumour induced granuloma need to be addressed. Moreover the biologic significance of such a granulomatous response in inducing tu-mour remission or in shielding tumour cells from host lymphocytes also requires further investigation.[...] Read More.
Keywords: Granuloma, cancer, metastasis.
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