Cheng-Hang Sun

Roseomonas vinacea sp. nov., a Gram-negative coccobacillus isolated from a soil sample

Strain CPCC 100056(T), which was isolated from a soil sample collected from the Qinghai-Tibet plateau, China, was subjected to a polyphasic taxonomic study. The organism was coccobacillus-shaped, non-motile and formed vinaceous colonies on ISP2 agar medium. The respiratory quinone was ubiquinone-10. The major fatty acids were C(18:1)omega7c and C(16:1)omega7c and/or C(16:1)omega6c. The G+C content of the genomic DNA was 67.3 mol%. A comparison of sequences in GenBank revealed that strain CPCC 100056(T) exhibited highest 16S rRNA gene sequence similarity (84.5-95.5%) with Roseomonas species. Strain CPCC 100056(T) could be distinguished from all Roseomonas species with validly published names by differences in phenotypic and genotypic properties. In view of the combined phenotypic, chemotaxonomic and phylogenetic data, strain CPCC 100056(T) should be classified as a representative of a novel species in the genus Roseomonas, Roseomonas vinacea sp. nov.; the type strain is CPCC 100056(T) (=KCTC 22045(T) =CCM 7468(T)).

Antimycin A 18 produced by an endophytic Streptomyces albidoflavus isolated from a mangrove plant

Antimycin A 18 produced by an endophytic Streptomyces albidoflavus isolated from a mangrove plant

Chemomicin A, a New Angucyclinone Antibiotic Produced by Nocardia mediterranei subsp. kanglensis 1747-64

A new angucyclinone antibiotic, chemomicin A was isolated from cultured broth of Nocardia mediterranei subsp. kanglensis 1747-64. Its chemical structure was determined to be 1,2,3,4a,5,6,6a,12a,12b-nonahydro-1,2,3,8,12,12b-hexahydroxy-3-methyl-6a,12a-epoxybenz[a]anthracen-4,7(12H)-dione by a detailed spectroscopic analysis. Chemomicin A had antimicrobial activity against Bacillus subtilis and Enterococcus faecium with MIC values of 10.2 and 20.4 μM, respectively, and showed cytotoxicity against human colorectal cancer HCT116 cells and human esophageal carcinoma YES-2 cells with IC50 values of 127 and 153 μM, respectively.

PJS, a novel isocoumarin with hexahydropyrimidine ring from Bacillus subtilis PJS

Amicoumacin group of antibiotics, such as baciphelacin,1 amicoumacins,2 AI-77s,3 xenocoumacins,4 Y-05460M-A,5 PM94128,6 Sg17-1-4,7 bacilosarcins A, B8 and lipoamicoumacins A–D,9 is a small family of isocoumarin, which possesses the common chromophore, 3, 4-dihydro-8-hydroxyisocoumarin. Most members of amicoumacin group of antibiotics are produced by the genus Bacillus and exhibit various important bioactivities. The chromophore shows specific UV absorbance at 247 and 314 nm in methanol. Thus, a project based on HPLC-diode array screening and HPLC-MS dereplication was carried out to find new amicoumacin analogues from the secondary metabolites of Bacillus spp. As a result, PJS (1), a new isocoumarin antibiotic was discovered from the fermentation broth of Bacillus subtilis PJS. In this study, we wish to report the fermentation, isolation, physico chemical properties, structural elucidation and biological activities of (1) (Figure 1). The producing strain Bacillus subtilis PJS was isolated from the leaf of an unidentified plant collected at Luopu county, Hetian area, Xinjiang Province, People’s Republic of China. On the basis of analysis of 16S rRNA, it was identified as Bacillus subtilis subsp. inaquosorum. A stock culture of the strain Bacillus subtilis PJS was maintained on modified Gause’s no. 1 agar slant consisting of soluble starch (Beijing Qi Te Xin Chemical Co. Ltd. China) 20.0 g, NaCl 50.0 g, K2HPO4 0.5 g, KNO3 1.0 g, MgSO4 1.0 g, FeSO4 0.02 g, glucose 1.0 g, peptone 0.5 g, tryptone 0.3 g and agar 20.0 g in 1.0 l distilled water (pH 8.0) at 4 1C. The stock culture was inoculated into 250 ml Erlenmeyer flasks containing 50 ml of seed medium, which was the same modified Gause’s no.1 liquid medium as above, but no agar. The culture was incubated on a rotary shaker (180 r.p.m.) at 28 1C for 24 h. Fifty millilitres of the seed culture was transferred to a 5000 ml Erlenmeyer flask containing 1000 ml of the producing medium, which was the same as the seed medium. The fermentation was carried out at 28 1C for 48 h on a rotary shaker (180 r.p.m.). Eighty liters of the fermentation broth was centrifuged at 4500 r.p.m. for 20 min, then, the supernatant was obtained and was extracted twice with 40 l of ethyl acetate each time. The organic layer was pooled and concentrated under reduced pressure at 37 1C to give yellow syrup (2.3 g). It was then separated by preparative thin layer chromatography on 10 10 cm plates (silica gel 60F254, Merck KGaA, Darmstadt, Germany) using CHCl3-MeOH, 65:35 (v/v) as the developing solvent. Under UV 365 nm, bands with light blue fluorescence at Rf 1⁄4 0.35 were scraped and then eluted with methanol to yield a semipurified sample (260 mg). After dissolved in 1 ml methanol, the sample was filtered through a 0.22mm membrane and was further purified by HPLC on a shim-Pack PRC-ODS column (250 20 mm, Shimadzu Corp., Tokyo, Japan) with MeOH-H2O, 55:45 (v/v) at 2 ml min 1. Peak at Rt1⁄4 26 min, showed UV absorbance at 247 and 314 nm detected by prominence diode array detector (SPD-M20A, Shimadzu), was collected and pooled to yield 10.4 mg of (1) as a white powder. Compound (1) was soluble in dimethyl sulfoxide (DMSO), MeOH, CHCl3 and pyridine. Its m.p. was 79–80 1C. MW of (1) was found to be 435 by high-resolution ESI-MS, which showed [MþH]þ at m/z 436.2089 (calcd 436.2079). The molecular formula was then established as C21H29O7N3, which has nine degrees of unsaturation. 13C-NMR and DEPT spectra of (1) indicated 21 carbon signals could be attributed to three carbonyl carbons, six aromatic carbons and 12 aliphatic carbons including six carbons bonded to nitrogen or oxygen. The UV absorption of (1) at lmax MeOH nm (e): 202(29 930), 246(6491) and 314(3491) was almost identical with that of isocoumarin compounds, such as Sg17-1-4, PM-94128, Y-05460M-A, bacilosarcins and AI-77-B. The IR spectrum (film) of (1) exhibited absorption bands at 3343, 2956, 1668, 1620, 1539, 1231, 807, 697 cm 1, which indicated the presence of a benzoic acid moiety with a phenolic hydroxyl group and an amide group. All data above revealed (1) had a

Actinopolymorpha cephalotaxi sp. nov., a novel actinomycete isolated from rhizosphere soil of the plant Cephalotaxus fortunei

An actinomycete, strain I06-2230(T), was isolated from rhizosphere soil of the plant Cephalotaxus fortunei, collected from Yunnan province, south China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belongs to the genus Actinopolymorpha. Cells grew on agar surfaces, with no penetration even after prolonged cultivation. Aerial hyphae were absent. Cells were irregularly shaped and remained attached as chains or aggregates. Chemotaxonomic data, which showed ll-diaminopimelic acid in the cell wall, glucose as the whole-cell sugar, type PI phospholipids and MK-9(H4) as the predominant menaquinone, supported the affiliation of strain I06-2230(T) to the genus Actinopolymorpha. The major fatty acids were iso-C(15 : 0), iso-C(16 : 0) and iso-C(16 : 1) H. The genomic DNA G+C content was 69.3 mol%. DNA-DNA hybridization data, in combination with chemotaxonomic, physiological and biochemical data, demonstrated that strain I06-2230(T) should be classified as representing a novel species of the genus Actinopolymorpha. The name Actinopolymorpha cephalotaxi sp. nov. is proposed, with strain I06-2230(T) (=DSM 45117(T)=CCM 7466(T)=KCTC 19293(T)) as the type strain.

Preliminary report on the biological effects of space flight on the producing strain of a new immunosuppressant, Kanglemycin C.

Kanglemycin C (K-C) is a new immunosuppressant isolated from the culture broth of Nocardia mediterranei var. kanglensis 1747-64. To improve the productivity of K-C and to study the biological effects of space flight on its producing strain, spores from five K-C producing strains (U-10, U-15, U-7, M-13, γ-33) mutated from the wild strain N. mediterranei var. kanglensis 1747-64 were carried into space by an unmanned spaceship, “Shenzhou III” (Divine Vessel III) on March 25, 2002. Comparatively, the strain U-7 was the highest K-C producing strain among the above five starting strains when cultivated in 500-ml Erlenmeyer flasks. After a 6xa0day and 18xa0h flight, the treated spores went through serial screening processes to screen for high-yield K-C mutant strains, using thin layer chromatography and high performance liquid chromatography (HPLC). The K-C yield produced by one mutant strain, designated as F-16, derived from the starting strain U-7 was increased by up to 200% when compared to that produced by the starting strain U-7 in 500-ml Erlenmeyer flasks after careful postflight HPLC analysis. Another mutant strain, designated as F-210, derived from the starting strain M-13 showed reduced productivity of K-C as well as exhibited changes in some morphological and physiological characteristics. For example, the broth color of the strain F-210 changed from yellow to purple after 96xa0h of culture, but that of the ground control strain M-13 remained yellow. Similarly, the mycelium morphological change from filamentous to coccoid of F-210 occurred later than that of ground control M-13. Examination of the survivability of postflight spores indicated that exposure to radiation, during the 162xa0h of space flight, plays a critical role in the survival rates of spores such that spores exposed to strong radiation exhibited lower survival rates than spores exposed to weak radiation.

In Vivo Antibacterial Activity of Vertilmicin, a New Aminoglycoside Antibiotic

ABSTRACT Vertilmicin is a novel aminoglycoside antibiotic with potent activity against gram-negative and -positive bacteria in vitro. In this study, we further evaluated the efficacy of vertilmicin in vivo in systemic and local infection animal models. We demonstrated that vertilmicin had relatively high and broad-spectrum activities against mouse systemic infections caused by Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecalis. The 50% effective doses of subcutaneously administered vertilmicin were 0.63 to 0.82 mg/kg, 0.18 to 0.29 mg/kg, 0.25 to 0.99 mg/kg, and 4.35 to 7.11 mg/kg against E. coli, K. pneumoniae, S. aureus, and E. faecalis infections, respectively. The therapeutic efficacy of vertilmicin was generally similar to that of netimicin, better than that of gentamicin in all the isolates tested, and better than that of verdamicin against E. coli 9612 and E. faecalis HH22 infections. The therapeutic efficacy of vertilmicin was further confirmed in local infection models of rabbit skin burn infection and mouse ascending urinary tract infection.

In Vitro Antibacterial Activity of Vertilmicin and Its Susceptibility to Modifications by the Recombinant AAC(6′)-APH(2″) Enzyme

ABSTRACT Vertilmicin is a new semisynthetic aminoglycoside with a structure similar to that of netilmicin except for a methyl group at the C-6′ position. In the present study, the in vitro antibacterial activity of vertilmicin was studied, and its susceptibility to modifications by the recombinant aminoglycoside bifunctional modifying enzyme AAC(6′)-APH(2″) was compared with those of verdamicin and netilmicin. A total of 1,185 clinical isolates collected from hospitals in Beijing between 2000 and 2001 were subjected to the in vitro antibacterial activity evaluations, including MIC, minimum bactericidal concentration (MBC), and time-kill curve tests. The MICs were evaluated in non-gentamicin-resistant (gentamicin-susceptible and gentamicin-intermediate) strains and gentamicin-resistant strains, respectively. For most of the non-gentamicin-resistant bacteria (except for the isolates of Pseudomonas spp.), the MIC90s of vertilmicin were in the range of 0.5 to 8 μg/ml, comparable to those of the reference aminoglycosides. For the gentamicin-resistant isolates, the three semisynthetic aminoglycosides (vertilmicin, netilmicin, and amikacin) demonstrated low MIC50s and/or MIC90s, as well as high percent susceptibility values. Among the study drugs, vertilmicin showed the lowest MIC90s, 16 μg/ml, for the gram-positive gentamicin-resistant isolates of Staphylococcus aureus and Staphylococcus epidermidis. Meanwhile, vertilmicin was a potent bactericidal agent, with MBC/MIC ratios in the range of 1 to 2 for Escherichia coli, Klebsiella pneumoniae, and S. aureus and 1 to 4 for S. epidermidis. The time-kill curve determination further demonstrated that this effect was rapid and concentration dependent. In evaluations of susceptibility to modifications by the recombinant AAC(6′)-APH(2″) with maximum rate of metabolism/Km measurements, vertilmicin exhibited susceptibilities to both acetylation and phosphorylation lower than those of netilmicin and verdamicin.