Zeaxanthin,an oxygenated carotenoid derivative with potent antioxidative properties,is produced by many organism taxa.Flavobacteriaceae are widely distributed in marine environments;however,the zeaxanthin biosynthesis...Zeaxanthin,an oxygenated carotenoid derivative with potent antioxidative properties,is produced by many organism taxa.Flavobacteriaceae are widely distributed in marine environments;however,the zeaxanthin biosynthesis property in this family remains incompletely explored.Here,we characterized zeaxanthin production by marine Flavobacteriaceae strains and elucidated underlying molecular mechanisms.Eight Flavobacteriaceae strains were isolated from the phycosphere of various dinoflagellates.Analyses of the zeaxanthin production in these strains revealed yields ranging from 5 to 3289μg/g of dry cell weight.Genomic and molecular biology analyses revealed the biosynthesized zeaxanthin through the mevalonate(MVA)pathway diverging from the 2-C-methyl-d-erythritol-4-phosphate(MEP)pathway commonly observed in most Gram-negative bacteria.Furthermore,comprehensive genome analyses of 322 culturable marine Flavobacteriale strains indicated that the majority of Flavobacteriaceae members possess the potential to synthesize zeaxanthin using precursors derived from the MVA pathway.These data provide insight into the zeaxanthin biosynthesis property in marine Flavobacteriaceae strains,highlighting their ecological and biotechnological relevance.展开更多
Fucoidan, a polysaccharide containing abundant fucose and sulfate ester group, was prepared from Laminaria japonica. In order to obtain fucoidan-degrading enzyme, bacteria capable of degrading fucoidan were screened f...Fucoidan, a polysaccharide containing abundant fucose and sulfate ester group, was prepared from Laminaria japonica. In order to obtain fucoidan-degrading enzyme, bacteria capable of degrading fucoidan were screened from kelp. A bacterial strain named RC2-3 was obtained, which degraded fucoidan by the maximum extent of 54% ± 1.3%, the highest among all bacterial isolates. High-performance size exclusion chromatography(HPSEC) showed that the molecular weight of fucoidan was gradually reduced by RC2-3 with culturing time, suggesting the production of fucoidan-degrading enzyme by RC2-3. Phylogenetic analysis of partial 16S ribosomal RNA gene(16S rDNA) sequence showed that RC2-3 belonged to the family Flavobacteriaceae. However, it showed different physiological and biochemical characteristics from the known Flavobacteriaceae members producing fucoidan-degrading enzyme, thus RC2-3 was proposed to be a new member of this family.展开更多
Objective:To investigate the clinical and epidemiological features and outcome of Chryseobacterium and Elizabethkingia spp.infections in children,together with antimicrobial susceptibilities.Methods:This retrospective...Objective:To investigate the clinical and epidemiological features and outcome of Chryseobacterium and Elizabethkingia spp.infections in children,together with antimicrobial susceptibilities.Methods:This retrospective study was conducted at a tertiary pediatric hospital in Turkey.All patients infected with Chryseobacterium/Elizabethkingia spp.among those presenting to Ankara City Hospital between March 2014 and March 2022 were included.Results:A total of 49 cases were included and 29 cases were identified as Elizabethkingia.The median age was 14(0.2-185.0)months.The majority(89.8%)of these patients had an underlying disease,including malignancy(42.9%).Bacteremia(46.9%)and central line-associated bloodstream infection(28.6%)were the most common infections.The thirty-day all-cause mortality rate was 12.2%.The most commonly used antibiotics were ciprofloxacin and trimethoprim-sulfamethoxazole(TMP-SMX).Forty-five(91.8%)isolates were susceptible to ciprofloxacin,44(91.6%)to TMP-SMX,and 21(87.5%)to levofloxacin.Conclusions:Chryseobacterium and Elizabethkingia spp.are emergent,nosocomial pathogens and the majority of cases were older than the neonatal period.They were mainly seen in patients with long hospital stays,indwelling devices,and those who have received antibiotics within the last month,especially carbapenems.In addition,they were associated with bloodstream infection and malignancy.The most commonly useful antibiotics according to the resistance patterns were ciprofloxacin and TMP-SMX.展开更多
基金provided by the Guangdong Basic and Applied Basic Research Foundation(2022B1515020017,2021A1515110426)the National Natural Science Foundation of China(32070113).
文摘Zeaxanthin,an oxygenated carotenoid derivative with potent antioxidative properties,is produced by many organism taxa.Flavobacteriaceae are widely distributed in marine environments;however,the zeaxanthin biosynthesis property in this family remains incompletely explored.Here,we characterized zeaxanthin production by marine Flavobacteriaceae strains and elucidated underlying molecular mechanisms.Eight Flavobacteriaceae strains were isolated from the phycosphere of various dinoflagellates.Analyses of the zeaxanthin production in these strains revealed yields ranging from 5 to 3289μg/g of dry cell weight.Genomic and molecular biology analyses revealed the biosynthesized zeaxanthin through the mevalonate(MVA)pathway diverging from the 2-C-methyl-d-erythritol-4-phosphate(MEP)pathway commonly observed in most Gram-negative bacteria.Furthermore,comprehensive genome analyses of 322 culturable marine Flavobacteriale strains indicated that the majority of Flavobacteriaceae members possess the potential to synthesize zeaxanthin using precursors derived from the MVA pathway.These data provide insight into the zeaxanthin biosynthesis property in marine Flavobacteriaceae strains,highlighting their ecological and biotechnological relevance.
基金the financial support from the National Natural Science Foundation of China(No.30800858)
文摘Fucoidan, a polysaccharide containing abundant fucose and sulfate ester group, was prepared from Laminaria japonica. In order to obtain fucoidan-degrading enzyme, bacteria capable of degrading fucoidan were screened from kelp. A bacterial strain named RC2-3 was obtained, which degraded fucoidan by the maximum extent of 54% ± 1.3%, the highest among all bacterial isolates. High-performance size exclusion chromatography(HPSEC) showed that the molecular weight of fucoidan was gradually reduced by RC2-3 with culturing time, suggesting the production of fucoidan-degrading enzyme by RC2-3. Phylogenetic analysis of partial 16S ribosomal RNA gene(16S rDNA) sequence showed that RC2-3 belonged to the family Flavobacteriaceae. However, it showed different physiological and biochemical characteristics from the known Flavobacteriaceae members producing fucoidan-degrading enzyme, thus RC2-3 was proposed to be a new member of this family.
文摘Objective:To investigate the clinical and epidemiological features and outcome of Chryseobacterium and Elizabethkingia spp.infections in children,together with antimicrobial susceptibilities.Methods:This retrospective study was conducted at a tertiary pediatric hospital in Turkey.All patients infected with Chryseobacterium/Elizabethkingia spp.among those presenting to Ankara City Hospital between March 2014 and March 2022 were included.Results:A total of 49 cases were included and 29 cases were identified as Elizabethkingia.The median age was 14(0.2-185.0)months.The majority(89.8%)of these patients had an underlying disease,including malignancy(42.9%).Bacteremia(46.9%)and central line-associated bloodstream infection(28.6%)were the most common infections.The thirty-day all-cause mortality rate was 12.2%.The most commonly used antibiotics were ciprofloxacin and trimethoprim-sulfamethoxazole(TMP-SMX).Forty-five(91.8%)isolates were susceptible to ciprofloxacin,44(91.6%)to TMP-SMX,and 21(87.5%)to levofloxacin.Conclusions:Chryseobacterium and Elizabethkingia spp.are emergent,nosocomial pathogens and the majority of cases were older than the neonatal period.They were mainly seen in patients with long hospital stays,indwelling devices,and those who have received antibiotics within the last month,especially carbapenems.In addition,they were associated with bloodstream infection and malignancy.The most commonly useful antibiotics according to the resistance patterns were ciprofloxacin and TMP-SMX.
