The Research Of Identification And Inhibitory Activity Of The Metabolic Products From Two Derived Fungi Isolated From Scleractinia

A wide variety of Scleractinia are an important branch of marine resources.At present,there are many studies about terrigenous fungi and its active products.While fewer studies focus on marine fungi.In some studies,it has shown that the symbiotic and epiphyte microorganisms in marine invertebrates can produce abundant antibacterial active substances.Besides,the ocean has breed lots of microbial populations and active products with novel structure due to its particular characteristics,such as hypoxia,high salinity and high pressure,which makes the marine symbiotic and epiphyte fungi a hotspot in the current researches.However,most scholars only researched on the active products of symbiotic and epiphyte fungi in the ocean,but it is rare to report on morphological studies.The population induction of marine fungi,as a basis for better developing and using active products of marine fungi,has yet to be further improved.Meanwhile,we need to take its optimum living conditions as references to know about the characteristics of coral-derived fungi.Therefore,I researched on two strains of coral-derived fungi with special structure,making identification of their species and exploring their physiological characteristics and biological activity,for the future development and utilization of these two strains of coral-derived fungi.(1)Morphological and molecular biological identification of two derived fungi isolated from Scleractinia:In combination with morphological and molecular identification methods,XWC14-13 was identified as Gongronella butleri.At initial stage of culture,The hypha is translucent and smooth,production small,smooth and transparent circular sporangium,culture in the late,form receptacle,the number of sporangium was increased,dark brown,round oval,flask,partial ripening and fall of,a large number of sporangiospores were released.And the strain XWC21-23 is Acremonium sclerotigenum.The mycelium is thin and transparent,conidia are transparent or brown,long oval,the outer wall is smooth,conidia from the top of the conidia stem to the side,the mucus glued the spores to a false head.(2)Physiologic characteristics of two derived fungi isolated from Scleractinia:MEA medium is the optimum medium for the growth of two coral-derived fungi.Through crossing method,measure the growth of colony under different gradients of temperature,p H and salinity.For temperature,the strain XWC14-13 can grow in the range of 15~35 ? rather than in the range of 0~10 ? and 40~50 ?.Its optimum growth temperature is 30 ?.As for the strain XWC21-23,the optimum growth temperature is 25 ?.It can grow in the temperature range of 15~30 ? rather than in temperature range of 0~10 ? and 35~50 ?.They are both suitable for growing in moderate temperature without characteristics of enduring high temperature and low temperature.In terms of p H,the strain XWC14-13 can grow in the range of 3~11 so that has an extensive tolerance of acid and alkali.Its optimum growth p H range is 8~8.5;the strain XWC21-23 can grow in the p H range of 6~11 but failure to grow below p H 6 and its optimum p H is 8.5.As a result,the strain has a little acid tolerance,but suitable for growing in alkaline conditions.For the salt concentration,the strain XWC14-23 can grow at the concentration of 0~10 %,and the optimum salt concentration is 1 %.The strain XWC21-23 can grow in the salt concentration range of 0~15 % and the optimum salt concentration is 3 %.Consequently,they can grow no matter there is salt or salt-free conditions,judged as facultative marine fungi.(3)Enzyme production characteristics and antimicrobial activities of two derived fungi isolated from Scleractinia:Two strains are cultured in enzyme producing medium in a way of hydrolyzed circle caused,of which value D stands for the size of enzyme.And the results showed that,the strain XWC13-14 has no ability of producing enzyme in all four medium.As for the strain XWC21-13,it can only produce cellulase and amylase.Both two strains have antimicrobial activity to aerugo pseudomonas SL1 by double-layer plate method.And through the shake-flask fermentation,we can improve its antimicrobial ability in a certain cultivate group and fermentation conditions.The result showed that,the best culture medium for the strain XWC14-13 is SDB medium,with 2 g of sucrose,1g of yeast extract,0.04 g of K2HPO4,under the condition of p H 8.5,30 ?and 150 rmp.Therefore,it will reach the best antimicrobial activity to the 7th day.The best culture medium for the strain XWC21-23 is PDB medium,with 2 g of glucose,no nitrogen source,0.04 g of K2HPO4,under the condition of p H 7,25 ?and 150 rmp,so that it can achieve the best antimicrobial activity in the 9th day.The activity products of two strains of culture broth were analyzed by thin layer chromatography,all contain amino acid,phenols,reducing substances,terpenes,steroid,anthracene,quinones,cholis acid,fatty acid,flavones,aromatic amines.The research has found that there are rare fungus on the surface of coral,for the first time,Gongronella butleri was isolated in the coral-derived fungi,of which the two strains not only have facultative marine fungi characteristics,but also have abilities of enzyme producing and antimicrobial activity.In this field,the deeper researches are needed on the completion of variety of coral-derived fungi as well as the activity development.