New secondary metabolites from an engineering mutant of endophytic Streptomyces sp. CS.

In previous work, a series of bioactive natural products had been isolated from the plant endophytic Streptomyces sp. CS, which was isolated from Maytenus hookeri. To mine new active metabolites, we describe introducing an alien carbamoyltransferase (asm21) gene into the strain CS by conjugal transfer. As a result, three recombinatorial mutants named CS/asm21-1, CS/asm21-2 and CS/asm21-4 were successfully constructed. Three mutants and wild type CS were cultured on solid medium, and the extracts were detected and analyzed by liquid chromatography-mass spectrometry (LC-MS). The LC-MS profiles showed several unknown peaks that were present in the spectra of extracts of the CS/asm21-4 cultured on oatmeal solid medium. Then, three new naphthomycins O-Q (1-3), a new macrolide hookerolide (4) as well as nine known compounds were obtained from the solid cultured medium. Their structures were identified by spectra data. These new compounds showed moderate antimicrobial activities.

Genome sequence and comparative analysis of Jiangella alba YIM 61503T isolated from a medicinal plant Maytenus austroyunnanensis.

A draft genome sequence of Jiangella alba YIM 61503T revealed a genome size of 7,664,864 bp arranged in 33 scaffolds. The genome was predicted to contain 7196 predicted genes, including 51 coding for RNA. Phylogenetic and comparative analyses of the draft genome of J. alba YIM 61503T with the available genomes of other Jiangella species suggested a proximal similarity between strains J. alba YIM 61503T and J. muralis DSM 45357T, while indicating a high divergence between J. gansuensis YIM 002T and other Jiangella species. The genome of J. alba YIM 61503T also revealed genes involved in indole-3-acetic acid biosynthesis and an alkylresorcinols gene cluster. Further, detection of phosphotransferase genes in the genome of all Jiangella species indicated that they can uptake and phosphorylate sugars. The presences of TreX-Z, TreS and OtsA-OtsB genes in some of the Jiangella strains also indicated a possible mechanism for their tolerance of high salinity. Besides providing new insights into its genetic features, our results suggested that J. alba YIM 61503T could be a potential strain for further genome mining studies. The release of this genome may, therefore, provide a better prospect for understanding "evolutionary taxonomy" about this genus in future.

Antimicrobial metabolites from endophytic Streptomyces sp. YIM61470.

Six compounds were isolated from Streptomyces sp. YIM61470, and their structures elucidated by spectral analysis as (R)-1-O-(phenylacetyl)glycerol (1), 4',5-dihydroxy-6-(3,3-dimethylallyl)-7-methoxyflavanone (2), (32R,33R,34S) -32,33,34,35-bacteriohopanetetrol (3), MKN-003C (4), cyclo (L-Pro-L-Gly) (5), and cyclo(L-Pro-L-Tyr) (6). Compound 1, an chiral monoacylglycerol, was isolated from a natural source for the first time. Compound 2 was first found in microorganisms, and compound 3, a bacteriohopanoid, was found first in the genus Streptomyces. Compounds 1-6 showed weak anti-microbial activity.

Promicromonospora xylanilytica sp. nov., an endophytic actinomycete isolated from surface-sterilized leaves of the medicinal plant Maytenus austroyunnanensis.

A novel xylan-degrading actinomycete, strain YIM 61515(T), was isolated from surface-sterilized leaves of the medicinal plant Maytenus austroyunnanensis. Cells were Gram-positive and non-spore-forming, produced primary branches and formed white to yellowish white colonies on the media tested. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 61515(T) was most similar to Promicromonospora aerolata V54A(T) and Promicromonospora vindobonensis V45(T) (99.4 and 99.1% sequence similarity, respectively). The isolate formed a separate lineage in a cluster containing P. aerolata V54A(T). 16S rRNA gene sequence similarity between the isolate and other members of the genus Promicromonospora ranged from 96.3 to 98.4%. Chemotaxonomic data, including major menaquinones, fatty acid compositions and polar lipid profiles, supported the placement of strain YIM 61515(T) in the genus Promicromonospora. DNA-DNA relatedness, physiological and biochemical data showed that strain YIM 61515(T) could be distinguished from members of all known species of the genus Promicromonospora and therefore represented a novel species. The name Promicromonospora xylanilytica sp. nov. is proposed, with YIM 61515(T) (=DSM 21603(T)=CCTCC AA 208046(T)) as type strain.

Molecular and morphological markers for rapid distinction between 2 Colletotrichum species.

Endophytic microorganisms reside asymptomatically within plants and are a source of new bioactive products for use in medicine, agriculture, and industry. Colletotrichum (teleomorph Glomerella) is a fungus widely cited in the literature as a producer of antimicrobial substances. Identification at the species level, however, has been a problem in this type of study. Several authors have reported the presence of endophytic fungi from the medicinal plant Maytenus ilicifolia ("espinheira-santa") in Brazil that has antimicrobial activity against various pathogens. Therefore, Colletotrichum strains were isolated from M. ilicifolia and identified based on morphology, RAPD markers, sequence data of the internal transcribed spacer regions (ITS-1 and ITS-2), the 5.8S gene, and species-specific PCR. The analyses suggested the presence of 2 species, Colletotrichum gloeosporioides and Colletotrichum boninense. Two morphological markers were characterized to allow C. gloeosporioides and C. boninense to be distinguished quickly and accurately. The molecular diagnosis of C. boninense was confirmed by using Col1 and ITS4 primers. This species of Colletotrichum is reported for the first time in M. ilicifolia.

Glycomyces scopariae sp. nov. and Glycomyces mayteni sp. nov., isolated from medicinal plants in China.

Two actinomycete strains, designated YIM 56256(T) and YIM 61331(T), were isolated from the roots of Scoparia dulcis and Maytenus austroyunnanensis, two Chinese medicinal plants, and their taxonomic status was established based on a polyphasic investigation. The organisms were found to have chemical and morphological markers typical of members of the genus Glycomyces. 16S rRNA gene sequence analysis showed that they were closely related to each other and to Glycomyces sambucus E71(T). A battery of physiological characteristics and levels of DNA-DNA relatedness indicated that strains YIM 56256(T) and YIM 61331(T) represent two novel species, clearly different from the related known Glycomyces species. On the basis of the data presented, it is evident that each of these strains represents a novel species of the genus Glycomyces, for which the names Glycomyces scopariae sp. nov. (type strain YIM 56256(T) =KCTC 19158(T) =DSM 44968(T)) and Glycomyces mayteni sp. nov. (type strain YIM 61331(T) =KCTC 19527(T) =CCTCC AA 208004(T)) are proposed.

Streptomyces mayteni sp. nov., a novel actinomycete isolated from a Chinese medicinal plant.

An actinomycete strain, designated YIM 60475(T), was isolated from the roots of Maytenus austroyunnanensis and was characterized by using a polyphasic approach. The strain was determined to belong to the genus Streptomyces, based on its phenotypic and phylogenetic characteristics. The strain produced spiral spore chains on aerial mycelium. The cell wall contained LL-diaminopimelic acid. Whole-cell hydrolysates contained galactose, glucose, and xylose. The phospholipid was type II. The DNA G+C content of the type strain was 73.3 mol%. DNA-DNA hybridization and comparison of physiological and chemical characteristics suggested that strain YIM 60475(T) is a new Streptomyces species, for which the name Streptomyces mayteni sp. nov. is proposed. The type strain is YIM 60475(T) (=CCTCC AA 207005(T) = KCTC 19383(T)).

Saccharopolyspora endophytica sp. nov., an endophytic actinomycete isolated from the root of Maytenus austroyunnanensis.

A Gram-positive, aerobic, non-motile, non-acid-alcohol-fast strain, designated YIM 61095(T), was isolated from the root of Maytenus austroyunnanensis collected from a tropical rainforest of Xishuangbanna in Yunnan Province, south-west China. Strain YIM 61095(T) exhibited chemotaxonomic and morphological characteristics that were consistent with members of the genus Saccharopolyspora. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YIM 61095(T) was a member of the genus Saccharopolyspora and was most closely related to Saccharopolyspora flava AS 4.1520(T) (97.7% sequence similarity). The major fatty acids were iso-C(15:0), iso-C(16:0), iso-C(17:0) and anteiso-C(17:0). The predominant quinone detected was MK-9(H(4)). The DNA G+C content was 66.2 mol%. The phenotypic characteristics and DNA-DNA hybridization relatedness data indicated that strain YIM 61095(T) should be distinguished from Saccharopolyspora flava AS 4.1520(T). On the basis of the evidence presented in this study, strain YIM 61095(T) represents a novel species of the genus Saccharopolyspora, for which the name Saccharopolyspora endophytica sp. nov. is proposed. The type strain is YIM 61095(T) (=KCTC 19397(T)=CCTCC AA 208003(T)).

Bioprospecting highly diverse endophytic Pestalotiopsis spp. with antibacterial properties from Maytenus ilicifolia, a medicinal plant from Brazil.

Thirteen endophytic fungal strains of the genus Pestalotiopsis were isolated from the medicinal plant Maytenus ilicifolia Mart. ex. Reiss (commonly known as "espinheira santa") and their antimicrobial properties were investigated. Two isolates were successful in inhibiting the growth of the tested microorganisms (Escherichia coli, Klebsiella pneumoniae, Micrococcus luteus, Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA)) using the technique of bioautographic thin-layer chromatography (TLC) agar overlay assay. An analysis based on a polyphasic approach integrating taxonomic information, morphological traits, RAPD markers, and the sequencing of the ITS1-5.8S-ITS2 of the rDNA led to the assignment of the isolates as belonging to the species Pestalotiopsis microspora, Pestalotiopsis vismiae, and Pestalotiopsis leucothoes. Therefore, the present study presents a new approach to the study of endophytic fungi of the genus Pestalotiopsis.