A hydrocarbon model of the modern aquatic plant Gloeocapsa and the aquatic animal mantis shrimp was found in thermal simulating experiment. The results show that the modern aquatic plant Gloeocapsa is characterized by...A hydrocarbon model of the modern aquatic plant Gloeocapsa and the aquatic animal mantis shrimp was found in thermal simulating experiment. The results show that the modern aquatic plant Gloeocapsa is characterized by late generation, late termination and a long duration of oil generation, while the aquatic animal mantis shrimp is characterized by early generation, early termination and a short duration of oil generation. The nalkanes from Gloeocapsa and mantis shrimp are characterized by peak carbon C 15 -C 17 . With increasing thermal simulating temperature, the peak carbon changes from C 17 to C 15 , and the odd-even predominance of nalkanes becomes less clear. The products from Gloeocapsa contain abundant phenanthrene and naphthalene compounds, and even a little retene, while those from mantis shrimp are dominated by naphthalene compounds, and are poor in phenanthrene compounds. Gloeocapsa and mantis shrimp are rich in C 27 sterane, relatively rich in tricyclic terpanes (C 19 -C 29 ) and hopanes (C 27 -C 35 ), poor in 5α,14β,17β sterane, and coprostane does not disappear until 450 ℃. The tricyclic terpanes in Gloeocapsa are characterized by peak carbon C 23 and C 23 >C 21 , and in mantis shrimp by C 21 and C 21 >C 23 . The content of pregnanes is very low at low temperature of thermal simulation, while above 360 ℃, high levels of pregnane series compounds and even degraded C 25 and C 26 steranes occur in thermal simulation products.展开更多
A unicellular-colonial cyanobacterium,designated“BRSZ,”was isolated from a neutral-alkaline hot spring in Thai-land.Morphological characterization revealed distinctive features consistent with those of the genus Glo...A unicellular-colonial cyanobacterium,designated“BRSZ,”was isolated from a neutral-alkaline hot spring in Thai-land.Morphological characterization revealed distinctive features consistent with those of the genus Gloeocapsa.Physiological assessments demonstrated that BRSZ is a moderately thermophilic and halotolerant cyanobacterium with the potential for chemoheterotrophic growth in dark conditions.Molecular phylogenetic analysis based on 16S ribosomal RNA(rRNA)gene sequences placed BRSZ within a well-defined Gloeocapsa clade,a finding cor-roborated by 16S-23S internal transcribed spacer(ITS)rRNA secondary structure analyses.Genome compar-isons,including average nucleotide identity(ANI),genome-to-genome distance(GGD),and digital DNA-DNA hybridization(dDDH),between strain BRSZ and closely related taxa showed an ANI value of 95.45%,near the lower boundary of the species delineation threshold(95-96%).A GGD of 0.0374(>0.0258)and dDDH of 69%(<70%)further supported genomic differentiation.Genome-based analysis revealed a mycosporine-like amino acid biosynthetic gene cluster likely involved in sunscreen compound production.Cultivation-based production of a UV-absorbing compound confirmed the functional relevance of this gene cluster.These findings expand the described diversity within the Gloeocapsa complex and enhance our understanding of the taxonomy of this group.In addition,they underscored the importance of hot spring environments as sources of novel extremophiles.展开更多
Since the first discovery of cyanobacterian plasmids in 1973, more than 60 strains have been found to have extra-chromosomal DNA, and their distribution covers almost all groups of the cyanobacteria. However, they wer...Since the first discovery of cyanobacterian plasmids in 1973, more than 60 strains have been found to have extra-chromosomal DNA, and their distribution covers almost all groups of the cyanobacteria. However, they were not discovered in the two unicellular genera Gloeocapsa and Gloeothece, and no further report was there on them ever since. Some species of these two genera having the ability to fix atmospheric nitrogen aerobically carry展开更多
基金the project 211at China University of Geosciences
文摘A hydrocarbon model of the modern aquatic plant Gloeocapsa and the aquatic animal mantis shrimp was found in thermal simulating experiment. The results show that the modern aquatic plant Gloeocapsa is characterized by late generation, late termination and a long duration of oil generation, while the aquatic animal mantis shrimp is characterized by early generation, early termination and a short duration of oil generation. The nalkanes from Gloeocapsa and mantis shrimp are characterized by peak carbon C 15 -C 17 . With increasing thermal simulating temperature, the peak carbon changes from C 17 to C 15 , and the odd-even predominance of nalkanes becomes less clear. The products from Gloeocapsa contain abundant phenanthrene and naphthalene compounds, and even a little retene, while those from mantis shrimp are dominated by naphthalene compounds, and are poor in phenanthrene compounds. Gloeocapsa and mantis shrimp are rich in C 27 sterane, relatively rich in tricyclic terpanes (C 19 -C 29 ) and hopanes (C 27 -C 35 ), poor in 5α,14β,17β sterane, and coprostane does not disappear until 450 ℃. The tricyclic terpanes in Gloeocapsa are characterized by peak carbon C 23 and C 23 >C 21 , and in mantis shrimp by C 21 and C 21 >C 23 . The content of pregnanes is very low at low temperature of thermal simulation, while above 360 ℃, high levels of pregnane series compounds and even degraded C 25 and C 26 steranes occur in thermal simulation products.
基金supported in part by the following research grants:Thai-land Science research and Innovation fund Chulalongkorn University(FOOD_FF_68_121_2300_022)(to RWS)the Singapore Ministry of Ed-ucation MOE-T2EP30123-0007(to RWS&SBP)+1 种基金the Research Institute of Meijo University(to HK)Postdoctoral Fellowship,the Second Century Fund(C2F),Chulalongkorn University(to SS).
文摘A unicellular-colonial cyanobacterium,designated“BRSZ,”was isolated from a neutral-alkaline hot spring in Thai-land.Morphological characterization revealed distinctive features consistent with those of the genus Gloeocapsa.Physiological assessments demonstrated that BRSZ is a moderately thermophilic and halotolerant cyanobacterium with the potential for chemoheterotrophic growth in dark conditions.Molecular phylogenetic analysis based on 16S ribosomal RNA(rRNA)gene sequences placed BRSZ within a well-defined Gloeocapsa clade,a finding cor-roborated by 16S-23S internal transcribed spacer(ITS)rRNA secondary structure analyses.Genome compar-isons,including average nucleotide identity(ANI),genome-to-genome distance(GGD),and digital DNA-DNA hybridization(dDDH),between strain BRSZ and closely related taxa showed an ANI value of 95.45%,near the lower boundary of the species delineation threshold(95-96%).A GGD of 0.0374(>0.0258)and dDDH of 69%(<70%)further supported genomic differentiation.Genome-based analysis revealed a mycosporine-like amino acid biosynthetic gene cluster likely involved in sunscreen compound production.Cultivation-based production of a UV-absorbing compound confirmed the functional relevance of this gene cluster.These findings expand the described diversity within the Gloeocapsa complex and enhance our understanding of the taxonomy of this group.In addition,they underscored the importance of hot spring environments as sources of novel extremophiles.
文摘Since the first discovery of cyanobacterian plasmids in 1973, more than 60 strains have been found to have extra-chromosomal DNA, and their distribution covers almost all groups of the cyanobacteria. However, they were not discovered in the two unicellular genera Gloeocapsa and Gloeothece, and no further report was there on them ever since. Some species of these two genera having the ability to fix atmospheric nitrogen aerobically carry
