Chaetoceros Ehrenberg is one of the most diverse genera of planktonic diatoms.The species in section Chaetoceros are characterized by cells and setae having numerous chloroplasts and being widely distributed.However,t...Chaetoceros Ehrenberg is one of the most diverse genera of planktonic diatoms.The species in section Chaetoceros are characterized by cells and setae having numerous chloroplasts and being widely distributed.However,the delimitations of some species are problematic because of limited morphological information in the classical descriptions.Monoclonal strains of the section Chaetoceros were established,morphological features were studied using light and electron microscopy,and the hypervariable D 1-D 3 region of the nuclear ribosomal large subunit gene was sequenced to address phylogenetic relationships.Fifteen species belonging to the section Chaetoceros were recorded,including two new species,C.hainanensis sp.nov.and C.tridiscus sp.nov.Chaetoceros hainanensis was characterized by straight chains,narrowly lanceolate to hexagonal apertures,sibling setae diverging in nearly right angles,stipule-shaped spines on terminal setae and arrowhead-shaped spines on intercalary setae.C.tridiscus had short straight chains,narrowly lanceolate apertures,arrowhead-shaped spines and circular poroids arranged in a grid pattern on terminal and intercalary setae.The phylogenetic analyses revealed six groups formed by 19 species within the section Chaetoceros,which was found to be monophyletic.The subdivision of the section is still not well understood.The morphological characters within each group varied considerably and molecular information on more species are needed to enrich the phylogenetic profiling.展开更多
本文对16个食线虫真菌(节丛孢属、隔指孢属和单顶孢属)菌株和3个其他相关丝孢菌(顶辐孢属和单端孢属)菌株的28S rDNA 片段进行了扩增, 并用限制性内切酶Sau3A I, Msp I, Rsa I and Hae III对PCR产物进行了消化。采用UPGMA法对 PCR 产物...本文对16个食线虫真菌(节丛孢属、隔指孢属和单顶孢属)菌株和3个其他相关丝孢菌(顶辐孢属和单端孢属)菌株的28S rDNA 片段进行了扩增, 并用限制性内切酶Sau3A I, Msp I, Rsa I and Hae III对PCR产物进行了消化。采用UPGMA法对 PCR 产物的限制性图谱特征进行了聚类分析。结果表明,捕食性真菌的聚类群与捕食器官类型相对应,顶辐孢属和单端孢属与捕食性真菌的遗传距离较远。该结果与rDNA 的ITS区间、5.8S和18S的序列分析结果一致。展开更多
A yeast-like fungus strain B1 isolated from wild fungus Tremella aurantialba was identified and initially characterized. Two phylogenetic trees were generated based on the sequences of large subunit ribosomal RNA gene...A yeast-like fungus strain B1 isolated from wild fungus Tremella aurantialba was identified and initially characterized. Two phylogenetic trees were generated based on the sequences of large subunit ribosomal RNA gene D1/D2 regions and internal transcribed spacer (ITS) regions of related fungi, respectively. The analysis of D1/D2 regions and ITS sequences showed that fungus B1 was clustered together with T. aurantialba, T. aurantia and T. microspore in the phylogenetic trees. Both the morphological characteristic and phylogenetic analysis established that fungus B1 was one of the anamorph strains of T. aurantialba and belongs to Tremella genus. A fermentation medium for exopolysaccharides (EPS) production by T. aurantialba B1 . Plackett-Burmen design was used to evaluate the effects of different components in the culture medium. Glucose and yeast extract have significant influence on the EPS production. The concentrations of two factors were optimized subsequently using central composite design and response surface analysis. The results showed that 49.2 g/L glucose and 10.4 g/L yeast extract could lead to the maximum production of EPS (4.99 g/L). The optimized medium led to a 1.5-fold enhancement of the production of EPS by T. aurantialba B1 , as compared with that without optimization.展开更多
基金Supported by the Joint Fund of National Natural Science Foundation of China and Chinese Shandong Province(No.U 2106205)the National Natural Science Foundation of China(No.32170206)the National Key Research and Development Program of China(No.2022YFC3105201)。
文摘Chaetoceros Ehrenberg is one of the most diverse genera of planktonic diatoms.The species in section Chaetoceros are characterized by cells and setae having numerous chloroplasts and being widely distributed.However,the delimitations of some species are problematic because of limited morphological information in the classical descriptions.Monoclonal strains of the section Chaetoceros were established,morphological features were studied using light and electron microscopy,and the hypervariable D 1-D 3 region of the nuclear ribosomal large subunit gene was sequenced to address phylogenetic relationships.Fifteen species belonging to the section Chaetoceros were recorded,including two new species,C.hainanensis sp.nov.and C.tridiscus sp.nov.Chaetoceros hainanensis was characterized by straight chains,narrowly lanceolate to hexagonal apertures,sibling setae diverging in nearly right angles,stipule-shaped spines on terminal setae and arrowhead-shaped spines on intercalary setae.C.tridiscus had short straight chains,narrowly lanceolate apertures,arrowhead-shaped spines and circular poroids arranged in a grid pattern on terminal and intercalary setae.The phylogenetic analyses revealed six groups formed by 19 species within the section Chaetoceros,which was found to be monophyletic.The subdivision of the section is still not well understood.The morphological characters within each group varied considerably and molecular information on more species are needed to enrich the phylogenetic profiling.
文摘本文对16个食线虫真菌(节丛孢属、隔指孢属和单顶孢属)菌株和3个其他相关丝孢菌(顶辐孢属和单端孢属)菌株的28S rDNA 片段进行了扩增, 并用限制性内切酶Sau3A I, Msp I, Rsa I and Hae III对PCR产物进行了消化。采用UPGMA法对 PCR 产物的限制性图谱特征进行了聚类分析。结果表明,捕食性真菌的聚类群与捕食器官类型相对应,顶辐孢属和单端孢属与捕食性真菌的遗传距离较远。该结果与rDNA 的ITS区间、5.8S和18S的序列分析结果一致。
基金Supported by the Key Project of National 9th Five-Year Plan Program (No.96-C02-03-06)
文摘A yeast-like fungus strain B1 isolated from wild fungus Tremella aurantialba was identified and initially characterized. Two phylogenetic trees were generated based on the sequences of large subunit ribosomal RNA gene D1/D2 regions and internal transcribed spacer (ITS) regions of related fungi, respectively. The analysis of D1/D2 regions and ITS sequences showed that fungus B1 was clustered together with T. aurantialba, T. aurantia and T. microspore in the phylogenetic trees. Both the morphological characteristic and phylogenetic analysis established that fungus B1 was one of the anamorph strains of T. aurantialba and belongs to Tremella genus. A fermentation medium for exopolysaccharides (EPS) production by T. aurantialba B1 . Plackett-Burmen design was used to evaluate the effects of different components in the culture medium. Glucose and yeast extract have significant influence on the EPS production. The concentrations of two factors were optimized subsequently using central composite design and response surface analysis. The results showed that 49.2 g/L glucose and 10.4 g/L yeast extract could lead to the maximum production of EPS (4.99 g/L). The optimized medium led to a 1.5-fold enhancement of the production of EPS by T. aurantialba B1 , as compared with that without optimization.
