The taxonomic relationship of Chinese GeBdium tsengii and Gelidium johnstonii was ambiguous. For almost 20 years they have been regarded as distinct taxa and until 2002 G.johnstonii was considered as a misapplied name...The taxonomic relationship of Chinese GeBdium tsengii and Gelidium johnstonii was ambiguous. For almost 20 years they have been regarded as distinct taxa and until 2002 G.johnstonii was considered as a misapplied name of G. tsengii. In this study, herbarium specimens that initially attributed to G. tsengii and fresh G. tsengii specimens were used to address the taxonomic issues. In phylogenetic studies, G. tsengii from Dayawan, China, near the type locality of G. tsengii and G.johnstonii from Sonora, Mexico, the type locality of G. johnstonii, formed a monophyletic group with maximum support in rbcL and COl genes analyses, indicating that they were genetically identical. In morphological studies, G. tsengii was similar to G. johnstonii in branching pattern, inner structures and fructiferous organs. Consequently, we considered that semi-circular outline of G. tsengii could no longer be treated as a discrimating fea^re. G.johnstonii had priority of publication and according to the International Code of Botanical Nomenclature, G. tsengii was proposed as a synonym of G. johnstonii. Gelidium honghaiwanense sp. nov. was described from Guangdong, China on the basis of morphological and molecular data. For vegetative structures, it was characterized by flattened upright frond, regular two-three times branches pinnate or alternate and clavate ultimate branchlets. For reproductive structures, the tetrasporangial sori were in the apical part of branches and the tetrasporangial branchlets were distichously distributed along second order branches. The present study clarified the relationship between G. tsengii and G. johnstonii from Guangdong and added a new Gelidium species to the Chinese algal flora.展开更多
A newly discovered enzyme, that can catalyze the formation of phosphotriester/-diester bonds between nucleic acids, was found to be associated with plant and animal viruses; （i.e. southern bean mosaic virus, brome mo...A newly discovered enzyme, that can catalyze the formation of phosphotriester/-diester bonds between nucleic acids, was found to be associated with plant and animal viruses; （i.e. southern bean mosaic virus, brome mosaic virus, influenza virus, avian virus and mouse retrovirus）. A partially purified enzyme from maize developing endosperms was prepared through 15%-35% ammonium sulfate fractionation, DEAE-cellulose anion exchange column chromatography and Sephadex GI50 gel filtration. The enzyme preparation was then used to demonstrate its main functional characteristics. The enzyme can use varieties of short and long chain length of nucleotides as substrates. However, the enzyme requires at least a minimum of 3 to 4 units of nucleotide chain length for the reaction to occur. The enzyme activity shows an optimum reaction in 50 mM sodium acetate buffer at pH 5.4 and is significantly inhibited by 6-azauridine as compared to other nucleotide analogs. By analyzing the data documented in literature and the results from the present study of the association of this enzyme with viruses and the distinctive inhibitory effect of 6-azauridine, it is speculated that this enzyme is likely associated with many other plant and animal viruses. The association of this enzyme on the surface of virus particles can be explored as a common antigen for developing a versatile antiviral vaccine.展开更多
基金Supported by the Strategic Leading Science and Technology Projects of Chinese Academy of Sciences(Nos.XDA11020404,XDA11020304)the China Postdoctoral Science Foundation(No.2016M592260)+1 种基金the National Natural Science Foundation of China(No.41376164)the Scientific and Technological Innovation Project fi nancially supported by Qingdao National Laboratory for Marine Science and Technology(No.2016ASKJ02)
文摘The taxonomic relationship of Chinese GeBdium tsengii and Gelidium johnstonii was ambiguous. For almost 20 years they have been regarded as distinct taxa and until 2002 G.johnstonii was considered as a misapplied name of G. tsengii. In this study, herbarium specimens that initially attributed to G. tsengii and fresh G. tsengii specimens were used to address the taxonomic issues. In phylogenetic studies, G. tsengii from Dayawan, China, near the type locality of G. tsengii and G.johnstonii from Sonora, Mexico, the type locality of G. johnstonii, formed a monophyletic group with maximum support in rbcL and COl genes analyses, indicating that they were genetically identical. In morphological studies, G. tsengii was similar to G. johnstonii in branching pattern, inner structures and fructiferous organs. Consequently, we considered that semi-circular outline of G. tsengii could no longer be treated as a discrimating fea^re. G.johnstonii had priority of publication and according to the International Code of Botanical Nomenclature, G. tsengii was proposed as a synonym of G. johnstonii. Gelidium honghaiwanense sp. nov. was described from Guangdong, China on the basis of morphological and molecular data. For vegetative structures, it was characterized by flattened upright frond, regular two-three times branches pinnate or alternate and clavate ultimate branchlets. For reproductive structures, the tetrasporangial sori were in the apical part of branches and the tetrasporangial branchlets were distichously distributed along second order branches. The present study clarified the relationship between G. tsengii and G. johnstonii from Guangdong and added a new Gelidium species to the Chinese algal flora.
文摘A newly discovered enzyme, that can catalyze the formation of phosphotriester/-diester bonds between nucleic acids, was found to be associated with plant and animal viruses; （i.e. southern bean mosaic virus, brome mosaic virus, influenza virus, avian virus and mouse retrovirus）. A partially purified enzyme from maize developing endosperms was prepared through 15%-35% ammonium sulfate fractionation, DEAE-cellulose anion exchange column chromatography and Sephadex GI50 gel filtration. The enzyme preparation was then used to demonstrate its main functional characteristics. The enzyme can use varieties of short and long chain length of nucleotides as substrates. However, the enzyme requires at least a minimum of 3 to 4 units of nucleotide chain length for the reaction to occur. The enzyme activity shows an optimum reaction in 50 mM sodium acetate buffer at pH 5.4 and is significantly inhibited by 6-azauridine as compared to other nucleotide analogs. By analyzing the data documented in literature and the results from the present study of the association of this enzyme with viruses and the distinctive inhibitory effect of 6-azauridine, it is speculated that this enzyme is likely associated with many other plant and animal viruses. The association of this enzyme on the surface of virus particles can be explored as a common antigen for developing a versatile antiviral vaccine.
