Study On The Isolation, Identification, Bioactivity Screening And Secondary Metabolites Of Cockroach Symbiotic Actinomycetes

Nature products are important source of Medicine.Many important clinical medicine are microbial secondary metabolites.Actinomycetes have a distinguished advantage in the field of producing antibiotics.About 75%of antibiotics are produced by actinomycetes.Many types of novel compound with good biological activities are found from animal symbiotic microbes.And entomic symbiotic actinomycete and its secondary metabolite is a new area for scientists.By studying entomic symbiotic actinomycete,we may find new medicine candidates and it may also help us to solve the problem of resistant pathogen.In this thesis,actinomycetes are isolated from cockroaches which are captured in students' dormitory.50 strains of actinomycetes are isolated from intestine and other purtenance.By molecular identification,and compare the 16S rDNA sequence online.All isolated actinomycetes belong to genus streptomyces.In antimicrobial activity test,15 stains(30%of the total number) showed antimicrobial activities against one or more sensitive microbes(Bacillus subtilis, Bacillus pumilus,Escherichia coli,Staphlococcus aureus,Candida albicans, Aspergillus niger).But all 15 strains have weak antimicrobial activities.In antitumor acitivity test,39 strains(78%of the total number) showed inhibition to the growth of HeLa cells.15(30%of the total number) of them showed very strong inhibition to the growth of HeLa cells.In this thesis,the study of secondary metabolites was carried on the two selected strains(A2-7 and A0-1),which have strong inhibition to HeLa cells. With liquid fermentation,9 compounds were isolated from strain A2-7.4 of them are novel compound.Q7,Q19 and Q27 are terpenoid.Q10 is furoic acid. The other 5 compounds are known compounds.Q1B and Q26 are furanone, Q11 is benzeneacetic Acid Phenyl Ester,Q16 is fatty acid,Q17 is indole derivate.With solid fermentation,only 1 known compound was isolated form strain A2-7,Q31 is benzeneacetamide.With solid fermentation,4 know compounds were isolated from strain A0-1.Q42 is amino acid,Q43 and Q44 are anthraquinone,Q47 is hydroxyl acetophenone.In the antimicrobial and antitumor tests of isolated novel compounds, none of the compounds showed antimicrobial activity and antitumor activity.The study on the cockroach symbiotic actinomycetes and their secondary metabolites indicated cockroach symbiotic actinomycetes have antimicrobial activity and antitumor activity.And the secondary metabolites are abundant in types.Some of them have antimicrobial activity or antitumor activity.And they might be new sources for novel compound with good biological activity.The study on entomic symbiotic actinomycetes may help in developing new antimicrobial and antitumor medicine.