تأثير بعض الظروف البيئية في نمو الفطر Microsprum canis المعزول من السعفة الحلقية في الإنسان وانتاجه لانزيم البروتيز المحلل للكيراتين

Abstract

Microsprum canis was isolated from the arm of patient suffering from Tinea corporis . The fungus was identified according to morphological (cultural and microbial) characteristics. The effects of environmental conditions on growth of the fungus were studied , the results showed M.canis appaered optimum growth on Sabourauds glucose agar (SGA) then Mycobiotic agar (MBA) and Potato glucose agar (PGA) at 25˚C for 14 days. The optimum temperature for fungus growth is 25˚C (35.5 mm on SGA agar plat for 14 days), whereas the fungus growth reached 33mm and 24mm on the same medium at 30˚C and 20˚C respectively and at the same incubation period. While the fungus had no ability to grow at 37˚C. The fungus growth appeared relationship with increasing incubation period up to 14 days. The growth reached 35.5mm at 14days,wherase the growth reached to 19, 25, 32.8 mm at 5, 7, 10 days respectivelly.The effects of environmental conditions on keratinolytic protease production from M.canis were studied using four type of proteins as sole nitrogenous source in medium including 2.6 gm/L of human hair, 2.6 gm/L of pepton, 2.6 gm/L of wheat bran , 1% gm/L of casein , as a result the fungus appeared an ability to produce different types of proteases . The fungus appeared enzyme activity 124U/ml in pepton broth filtrate, whereas the protease activity reached to 20 and 48.5 U/ml in wheat bran filtrate and hair medium filtrate respectivelly.while the casein medium filtrate contain 16 U/ml of enzyme activity. The fungus was induced to produce keratinolytic protease in human hair medium at different hair concentrations , the results appeared that 5.2gm/ L of human hair was the best concentration to reach maximum enzyme production (40 U/ml), whereas the activity reduced to 3U/ml at 13 gm/ L human hair. The optimum pH of maximum enzyme production is 9 in comparison with neutral and acid pH of production media. The effect of temperature on enzyme production was studied using 5.2 gm/L human hair medium at 9pH , the results appeared the optimum temperature for enzyme production (45U/ml) was 35˚C but at 20˚C the production was reduced and the activity reached to 5U/ml. The aeration and agitation of production media is effected on enzyme production from M.canis , the maxium production (49.5 U/ml) occurred with non continuously aeration (without aeration for five days after that aerated for five days) in comparison with continuously or non aerated . The maximum enzyme production reached after nin days of incubation period with non continuously aeration.