ABSTRACT
Two novel cyclopeptides with special skeleton, namely, dolyemycins A (1) and B (2) were isolated from Streptomyces griseus subsp. griseus HYS31 by bio-guided isolation. Their structures were elucidated by detailed analysis of spectroscopic data. These two compounds were cyclopeptides containing eleven amino acids including five unusual amino acids (hydroxyglycine, 3-hydroxyleucine, 3-phenylserine, ß-hydroxy-O-methyltyrosine, 2,3-diaminobutyric acid) in both of them and an extra nonprotein amino acids (3-methylaspartic acid) in Dolyemycin B only. Dolyemycins A and B performed antiproliferative activity against human lung cancer A549 cells with IC50 values of 1.0 and 1.2 µM, respectively.
Subject(s)
Peptides, Cyclic/chemistry , Streptomyces griseus/chemistry , A549 Cells , Amino Acid Sequence , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Antineoplastic Agents/pharmacology , Humans , Models, Molecular , Peptides, Cyclic/metabolism , Peptides, Cyclic/pharmacology , Protein Conformation , Streptomyces griseus/metabolismABSTRACT
Two novel γ-butyrolactones ghanamycins A (1) and B (2) were isolated from the fermentation broth of marine-derived Streptomyces ghanaensis TXC6-16. Their structures were elucidated by spectroscopic analysis. These two novel compounds exhibited antimicrobial activities against some phytopathogens. The minimum IC (MIC) of 2 against Pseudomonas syringae and Erwinia sp. were 50 µg ml-1.
Subject(s)
4-Butyrolactone/analogs & derivatives , 4-Butyrolactone/isolation & purification , Anti-Infective Agents/isolation & purification , Streptomyces/metabolism , 4-Butyrolactone/chemistry , 4-Butyrolactone/pharmacology , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Erwinia/drug effects , Fermentation , Microbial Sensitivity Tests , Pseudomonas syringae/drug effects , Spectrum AnalysisABSTRACT
An effective CO2 supply system of a spraying absorption tower combined with an outdoor ORWP (open raceway pond) for microalgae photoautotrophic cultivation is developed in this paper. The microalgae yield, productivity and CO2 fixation efficiency were investigated, and compared with those of bubbling method. The maximum yield and productivity of biomass were achieved 0.927gL(-1) and 0.114gL(-1)day(-1), respectively. The fixation efficiency of CO2 by microalgae with the spraying tower reached 50%, whereas only 11.17% for bubbling method. Pure CO2 can be used in the spraying absorption tower, and the flow rate was only about one third of the bubbling cultivation. It shows that this new method of quantifiable control CO2 supply can meet the requirements of the growth of microalgae cultivation on large-scale.
Subject(s)
Carbon Dioxide/chemistry , Microalgae/growth & development , Biomass , Carbon Dioxide/metabolism , Conservation of Energy Resources , Photobioreactors , PhotosynthesisABSTRACT
Two new cyclic lipopeptides maribasins A (1) and B (2) were isolated from the fermentation broth of the marine microorganism Bacillus marinus B-9987 isolated from Suaeda salsa in Bohai coastline of P. R. China. Both structures were established to be cyclo (D-Pro-L-Gln-L-Asn-L-Ser-D-Asn¹-D-Tyr-D-Asn²-D-ß-aminoisopentadecanoic acid) (1) and cyclo (D-Pro-L-Gln-L-Asn-L-Ser-D-Asn¹-D-Tyr-D-Asn²-D-ß-aminoanteisopentadecanoic acid) (2) by spectroscopic analysis and exhibited broad-spectrum activity against phytopathogens by the antifungal bioassay.
Subject(s)
Antifungal Agents/chemistry , Bacillus/metabolism , Lipopeptides/chemistry , Peptides, Cyclic/chemistry , Amino Acid Sequence , Antifungal Agents/isolation & purification , Antifungal Agents/pharmacology , Lipopeptides/isolation & purification , Lipopeptides/pharmacology , Magnetic Resonance Spectroscopy , Microbial Sensitivity Tests , Molecular Conformation , Peptides, Cyclic/isolation & purification , Peptides, Cyclic/pharmacologyABSTRACT
To study the spectral characteristic of TiO2/SnO2, TiO2/SnO2 composite oxide with SnO2 inside kernel was fabricated by colloid chemistry method, and was studied with UV-visible absorption spectrum, X-ray diffraction and infrared spectrum. The results showed that the bandgap widths of TiO2 and TiO2/SnO2 were 4.13 and 3.86 eV, respectively. TiO2/SnO2 had a widest and strong absorption band in the ultraviolet range. There was a quantum effect. In the X-ray diffraction, the station of TiO2 (110) diffraction peak moved 1.6 degrees, and its intensity changed. Compared with TiO2 infrared spectrum, the Ti--O stretching vibration of TiO2/SnO2 moved from 500 to 656 cm(-1), and had 560 cm(-1) shoulder peak. The intensity of the peaks near 1 650 and 3 420 cm(-1) corresponding to water absorbing peaks increased.
ABSTRACT
Quantitative detection of a biological affinity reaction, the biotin/avidin recognition, was achieved using our newly developed photoelectrochemical analytical system. The system is based on the operation mechanism of the well-developed dye-sensitized photoelectrochemical solar cells and comprises a ruthenium tris(2,2'-bipyridine) (Ru-bipy) derivative as the photoelectrochemical signal-generating molecule, oxalate as the sacrificial electron donor, and tin oxide nanoparticle as the semiconductor electrode material. To perform the affinity reaction, avidin was immobilized on SnO(2) electrode by passive adsorption. Biotin-linked bovine serum albumin (BSA) was labeled with an NHS-ester derivative of Ru-bipy. After binding of BSA to the surface-immobilized avidin through biotin, photoelectrochemical measurement was carried out in the presence of oxalate. Anodic photocurrent was turned on and off repeatedly by control of incidental light. The action spectrum of the photocurrent resembled the absorption spectrum of Ru-bipy, proving the photocurrent was generated from the metal complex. A linear relationship between photocurrent and BSA concentration was obtained in the range of 1-100 microg/mL. This is the first case of quantitative photoelectrochemical detection of a biological affinity interaction.
