Thirty-two actinomycetes strains were isolated from sediment samples from 12 different sites at Lagos Lagoon and identified using standard physiological and biochemical procedures as well as 16S rDNA gene sequence ana...Thirty-two actinomycetes strains were isolated from sediment samples from 12 different sites at Lagos Lagoon and identified using standard physiological and biochemical procedures as well as 16S rDNA gene sequence analysis. Secondary metabolites were extracted from the strains and their anticancer activity on the K562 (Human acute myelocytic leukemia), HeLa (cervical carcinoma), AGS (Human gastric), MCF- 7 (breast adenocarcinoma) and HL-60 (Human acute promyelocytic leukemia) cell lines was determined. The metabolic extracts exhibited cytotoxicity with IC50 values ranging from 0.030 mg/mL to 4.4 mg/mL. The Streptomyces bingchenggensis ULS14 extract was cytotoxic against all the cell lines tested. The bioactivity-guided extraction and purification of the metabolic extracts from this strain yielded two purified anticancer compounds: ULDF4 and ULDF5. The structures of the extracted compounds were determined using spectroscopic analyses, including electrospray ionization mass spectrophotometer and nuclear magnetic resonance (1 Dimensional and 2 Dimensional), and were shown to be structurally similar to staurosporine and kigamicin. The IC50 of ULDF4 and ULDF5 against the HeLa cell line was 0.034 mg/mL and 0.075 mg/mL, respectively. This study is the first to reveal the anticancer potential of actinomycetes from Lagos Lagoon, which could be exploited for therapeutic purposes.展开更多
Lanthanide triflates are stable in water. It is possible for lanthanides to undergo many organic reactions in environmentally friendly solvents. This makes lanthanides very promising in the field of green chemistry. T...Lanthanide triflates are stable in water. It is possible for lanthanides to undergo many organic reactions in environmentally friendly solvents. This makes lanthanides very promising in the field of green chemistry. This review describes the recent development of the lanthanide-catalyzed organic reactions in protic solvents. Those reac-tions include Diels-Alder, Aldol, Allylation, acetalization, pericyclization, radical reactions as well as some newly-developed lanthnides-based catalysts.展开更多
ABO blood group system was firstly recognized by Landsteiner in 1900[1].Since then,the antigens of the ABO system (A,B and H determinants,respectively)have been shown to encompass complex carbohydrate structures [2].A...ABO blood group system was firstly recognized by Landsteiner in 1900[1].Since then,the antigens of the ABO system (A,B and H determinants,respectively)have been shown to encompass complex carbohydrate structures [2].A and B antigen were synthesized by the sequential action of glycosyltransferases,with A and B glycosyltransferases catalyzing the addition of N-acetylgalactosamine and D-galactose to precursor H antigen,respectively. Group O individuals lack such transferase enzymes and consequently continue to express the basic H structure only [3,4].It is determined that approximate 2million ABH glycan antigen sites are presented on each red blood cell [5].Additionally,the ABH antigens are widely expressed in other human ceils and tissues,including the sensory neurons,epithelium,the vascular endothelium and platelets [6].展开更多
Dear Editor,The human gastrointestinal tract is colonized by trillions of microorganisms,the majority of which cannot be cultured (Wu et al.,2018).Numerous glycans are expressed on the surface of gut microbiota that a...Dear Editor,The human gastrointestinal tract is colonized by trillions of microorganisms,the majority of which cannot be cultured (Wu et al.,2018).Numerous glycans are expressed on the surface of gut microbiota that are characteristic of different strains,and the diversity of these glycans is partially attributed to variations in their monosaccharides.展开更多
基金supported by the University of Lagos Central Research Committee Grant (Grant No: ULCRC 2012/08)
文摘Thirty-two actinomycetes strains were isolated from sediment samples from 12 different sites at Lagos Lagoon and identified using standard physiological and biochemical procedures as well as 16S rDNA gene sequence analysis. Secondary metabolites were extracted from the strains and their anticancer activity on the K562 (Human acute myelocytic leukemia), HeLa (cervical carcinoma), AGS (Human gastric), MCF- 7 (breast adenocarcinoma) and HL-60 (Human acute promyelocytic leukemia) cell lines was determined. The metabolic extracts exhibited cytotoxicity with IC50 values ranging from 0.030 mg/mL to 4.4 mg/mL. The Streptomyces bingchenggensis ULS14 extract was cytotoxic against all the cell lines tested. The bioactivity-guided extraction and purification of the metabolic extracts from this strain yielded two purified anticancer compounds: ULDF4 and ULDF5. The structures of the extracted compounds were determined using spectroscopic analyses, including electrospray ionization mass spectrophotometer and nuclear magnetic resonance (1 Dimensional and 2 Dimensional), and were shown to be structurally similar to staurosporine and kigamicin. The IC50 of ULDF4 and ULDF5 against the HeLa cell line was 0.034 mg/mL and 0.075 mg/mL, respectively. This study is the first to reveal the anticancer potential of actinomycetes from Lagos Lagoon, which could be exploited for therapeutic purposes.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29928004).
文摘Lanthanide triflates are stable in water. It is possible for lanthanides to undergo many organic reactions in environmentally friendly solvents. This makes lanthanides very promising in the field of green chemistry. This review describes the recent development of the lanthanide-catalyzed organic reactions in protic solvents. Those reac-tions include Diels-Alder, Aldol, Allylation, acetalization, pericyclization, radical reactions as well as some newly-developed lanthnides-based catalysts.
基金financially supported by the State Key Laboratory of Microbial Technology Projects Fund and the National Natural Science Foundation of China (31770997)the Science and Technology Program of Guangdong Province (2016A020216021)+1 种基金the Major International Joint Research Program of China (31420103901)the Program of Introducing Talents of Discipline to Universities (B16021)
文摘ABO blood group system was firstly recognized by Landsteiner in 1900[1].Since then,the antigens of the ABO system (A,B and H determinants,respectively)have been shown to encompass complex carbohydrate structures [2].A and B antigen were synthesized by the sequential action of glycosyltransferases,with A and B glycosyltransferases catalyzing the addition of N-acetylgalactosamine and D-galactose to precursor H antigen,respectively. Group O individuals lack such transferase enzymes and consequently continue to express the basic H structure only [3,4].It is determined that approximate 2million ABH glycan antigen sites are presented on each red blood cell [5].Additionally,the ABH antigens are widely expressed in other human ceils and tissues,including the sensory neurons,epithelium,the vascular endothelium and platelets [6].
基金supported by the State Key Laboratory of Microbial Technology Projects Fundthe National Natural Science Foundation of China(31770997,31500648)
文摘Dear Editor,The human gastrointestinal tract is colonized by trillions of microorganisms,the majority of which cannot be cultured (Wu et al.,2018).Numerous glycans are expressed on the surface of gut microbiota that are characteristic of different strains,and the diversity of these glycans is partially attributed to variations in their monosaccharides.