Rhodotorula glutinis and Its Two Mutants Ameliorate Hepato-Renal Dysfunction Induced by Ochratoxin A on Rats.

Aim: This study was designed to investigate the possible curative effect of Rhodotorula glutinis (R. glutinis) and its two mutants (Col-1R1 and Col-1R3) against hepatorenal toxicity induced by ochratoxin (OA) in rat. Methods: The strains of yeast Col- 1R1 and Col- 1R3 have been genetically improved and isolated from R. glutinis after colchicines treatment. OA was produced and determined from Aspergillus ochracus isolate from Egyptian corn. Experimental design: Five groups of rats were treated as follows: group 1, was the control group orally given 4 ml / Kg 0.1 M NaCOH3; group 2 treated with OA (1.7 mg /Kg).Groups 3, 4 and 5 orally administered the R. glutinis and its two mutants (50 X106 colony forming unit (cfu) / 10 ml saline / kg body weight) prior 1hr of OA -treatment for 15 successive days. Results: The studied autoploidy strains showed significant increase in caratenoids level, protease, β-1, 3-glucanase and chitinase activities when compared with the parental strain. Biochemical results revealed that OA significantly decreased serum total antioxidant capacity (TAC) and it caused elevation inserum transaminases (AST, ALT), creatinine, uric acid, nitric oxide (NO), tumor necrosis factor alpha (TNF-α) and carcinoembryonic antigen (CEA) (P <0.05) as compared with the control group. The three tested yeasts significantly decreased the elevated values toward the normal levels and improved the pathological feature in liver and kidney tissues. Moreover, R. glutinis and the two mutants significantly reduced hepatorenal damaged arias, increased optical density of DNA and alleviated ochratoxin A-induced caspase-3 activation. The resultant effect of the two mutant strains had more powerful effect more than the wild strainto ameliorate hepatorenal dysfunction in ochratoxicosis-rat. Conclusion: Col-1R3 was more effective than Col-1R1 may be due to its higher contents of carotenoids, glucane and chitine, which act as antioxidants.

Identification of Some Rice Genotypes Resistant to Blast Disease in Egypt.

Blast disease caused by Pyricularia oryzae, is the most important disease of rice in Egypt and in the world. Field surveys in main production regions, revealed that the highest disease incidence was recorded in El-Behera Governorate. Seven rice cultivars were screened for resistance to blast disease. Resistance to disease was studied under both artificially and naturally with local pathogen. A bioassay was developed based on (0-9) scale, Area Under the Disease Progress Curve (AUDPC), disease area and sporulation. Differential expression to pathogen was observed between cultivars. Among seven cultivars, Sakha 101 and Sakha 103 were highly resistant and Giza 175 and Giza 178 were highly susceptible to three strains of fungus P. oryzae. Meanwhile other lines showed moderate resistance and susceptible. At the same time there were great differences concerning the growth rate and yield between different rice cultivars.

Biocontrol potential of salinity tolerant mutants of Trichoderma harzianum against Fusarium oxysporum

A exposição de uma cepa selvagem de Trichoderma harzianum à irradiação gama induziu dois mutantes tolerantes a sal (Th50M6 e Th50M11). Em condições salinas, os dois mutantes foram muito superiores à cepa selvagem em relação à velocidade de multiplicação, esporulação e eficiência contra Fusarium oxysporum, o agente causador da doença wilt do tomate. Os mutantes tolerantes foram capazes de multiplicação e esporulação em meio de cultura contendo NaCl até 69 mM. Em comparação à cepa selvagem, os dois mutantes possuíam conteúdo mais elevado de prolina e hidroxiprolina, conteúdo de sódio superior ao de potássio, cálcio ou magnésio e conteúdo elevado de fenóis totais. A análise eletroforética das proteínas totais solúveis no mutante Th50M6 apresentou bandas diferentes acumuladas em resposta a NaCl 69 mM. Os resultados também indicaram que os mutantes produzem alguns metabólitos ativos como quitinases, celulases, b-galactosidades e antibióticos como tricodermina, gliotoxina e gliovirina. Os mutantes de Trichoderma reduziram significativamente a incidência da doença e melhoraram o rendimento e o conteúdo de minerais do tomate tanto em condições salinas como não-salinas e também em condições naturais e de infestação. Quando comparados à cepa selvagem, os mutantes de Trichoderma foram também mais eficientes em diminuir o crescimento de F. oxysporum na rizosfera.A densidade populacional de ambos mutantes na rizosfera excedeu muito a da cepa selvagem.