title: [Diversity of cultivable actinobacteria in Xinghu wetland sediments].
abstract: OBJECTIVE
  To study the diversity of cultivable actinobacteria in Xinghu wetland and screen actinobacteria with a pharmaceutical potential for producing biologically active secondary metabolites.
  
  
  METHODS
  We studied the diversity of actinobacteria isolated from Xinghu wetland by using different selective isolation media and methods. The high bioactive actinobacteria were identified and further investigated for the presence of polyketide synthases (PKS-I, PKS-II), nonribosomal peptide synthetases (NRPS), 3-amino-5-hydroxybenzoic acid synthases (AHBA) and 3-hydroxy-3-methylglutaryl Coenzyme A (HMG CoA) sequences by specific amplification.
  
  
  RESULTS
  More than 300 actinobacteria were isolated, and 135 isolates were selected on the basis of their morphologies on different media and were further characterized by 16S rRNA gene sequencing. The isolates belonged to 7 orders, 10 families, 13 genera, Streptomyces was the most frequently isolated genus, followed by the genera Micromonospora and Nocardia. Twenty-four isolates showed high activity against Staphylococcus aureus and Escherichia coli, but there no strain displaying antagonistic activity against Salmonella sp. High frequencies of positive PCR amplification were obtained for PKS-I (16.7%, 4/24), PKS-II (62.5%,15/24), NRPS (16.7%, 4/24), HMG CoA (29.2%, 7/24) and AHBA (12.5%, 3/24) biosynthetic systems. High Performance Liquid Chromatography showed that strain XD7, XD114, XD128 produce lots of secondary metabolites.
  
  
  CONCLUSIONS
  This study indicated that actinobacteria isolated from Xinghu wetland are abundant and have potentially beneficial and diverse bioactivities which should be pursued for their biotechnical promise.
authors.forename: Dong
authors.initials: D
authors.lastname: Xue
authors.forename: Guozhen
authors.initials: G
authors.lastname: Zhao
authors.forename: Qing
authors.initials: Q
authors.lastname: Yao
authors.forename: Haiquan
authors.initials: H
authors.lastname: Zhao
authors.forename: Honghui
authors.initials: H
authors.lastname: Zhu
mesh_terms: D039903:Actinobacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification*; D044822:Biodiversity; D002681:China; D019015:Geologic Sediments / Q000382:microbiology*; D008969:Molecular Sequence Data; D010802:Phylogeny; D053833:Wetlands