Colcemid treatment of myeloma prior to cell fusion increases the yield of hybridomas between myeloma and splenocyte

Effect of Colcemid treatment of myeloma (X63-Ag8-6.5.3.) prior to fusion with mouse spleen cell was studied in terms of hybridoma formation. Spleen cells from BALB/c mice immunized with various soluble antigens were fused with the myeloma cells by using polyethylene glycol solution. Colcemid treatment of myeloma cells prior to fusion increased the average number of hybridoma colonies per well by 26-570%. The yield of hybridomas producing antigen-specific antibodies was also higher with the Colcemid treatment. The results suggest that most of the proliferative hybridomas are formed by fusion of cells in the M-phase of the cell cycle.     

Leaf traits of natural populations of <Emphasis Type="Italic">Adiantum reniforme</Emphasis> var. <Emphasis Type="Italic">sinensis</Emphasis>, endemic to the Three Gorges region in China

Leaf mass per unit area (LMA), carbon and nitrogen contents, leaf construction cost, and photosynthetic capacity (P _max) of Adiantum reniforme var. sinensis, an endangered fern endemic to the Three Gorges region in southwest China, were compared in five populations differing in habitat such as soil moisture and irradiance. The low soil moisture and high irradiance habitat population exhibited significantly higher LMA, area-based leaf construction (CC_A), and carbon content (C_A), but lower leaf nitrogen content per unit dry mass (N_M) than the other habitat populations. The high soil moisture and low irradiance habitat populations had the lowest CC_A, but their cost/benefic ratios of CCA/P _max were similar to the medium soil moisture and irradiance habitat population due to their lower leaf P _max. Hence A. reniforme var. sinensis prefers partially shaded, moist but well-drained, slope habitats. Due to human activities, however, its main habitats now are cliffs or steeply sloped bare rocks with poor and thin soil. The relatively high energy requirements and low photosynthetic capacity in these habitats could limit the capability of the species in extending population or interspecific competition and hence increase its endangerment.     

Morphological and molecular investigations of Tubulinosema ratisbonensis gen. nov., sp. nov. (Microsporidia: Tubulinosematidae fam. nov.), a parasite infecting a laboratory colony of Drosophila melanogaster (Diptera: Drosophilidae)

A new species of microsporidia from Drosophila melanogaster was investigated by light and electron microscopy and by ribosomal RNA (rRNA) sequencing. This microsporidium and the previously described Nosema kingi and Nosema acridophagus have been transferred to the new genus Tubulinosema gen. nov. with the following characters: nuclei are in diplokaryotic arrangement during the life cycle. All stages are in direct contact with the host cell cytoplasm, slightly anisofilar polar tube with the last coils being smaller in diameter arranged in one or two rows on both sides of the diplokaryon and small tubuli on the surface of late meronts. Spores are oval or slightly pyriform. Thick endospore wall, thinner over anchoring disc. This new genus and the genus Brachiola have been placed in a new family Tubulinosematidae fam. nov. Phylogenetic analysis of small subunit rRNA sequences by different methods placed Tubulinosema spp. in one clade with the genus Brachiola forming its sister clade, which is distant from the clade containing the true Nosema spp. including Nosema bombycis.     

稻纵卷叶螟感染Wolbachia的ftsZ基因和16S rDNA基因的序列分析

Wolbachia是一类胞质遗传的内共生菌, 广泛分布于节肢动物和其他动物中, 与宿主的生殖调控密切相关。通过研究迁飞性害虫稻纵卷叶螟Cnaphalocrocis medinalis (Guenée)的Wolbachia感染情况, 为探讨Wolbachia在迁飞性昆虫中的生殖调控和传递方式等提供基础资料。本研究应用Wolbachia的ftsZ基因和16S rDNA基因的特异性引物, 通过PCR扩增的方法对我国20个地区的稻纵卷叶螟样本进行了检测。结果表明: 中国不同地区的稻纵卷叶螟感染Wolbachia的现象较为普遍, 其中浙江温州和江苏扬州样本的感染率最高（90%）; 四川雅安、 湖南长沙和天津宁河样本的感染率最低（40%）。不同地区稻纵卷叶螟的Wolbachia ftsZ基因序列完全一致, 而且不同地区的Wolbachia 16S rDNA基因序列也完全相同。此外, 稻纵卷叶螟感染的Wolbachia ftsZ基因和16S rDNA基因序列与其他物种感染的Wolbachia B群的ftsZ基因序列和16S rDNA基因序列相似性分别在99%~100%和98%~99%之间, 说明我国稻纵卷叶螟感染的Wolbachia隶属B群。研究结果表明, 稻纵卷叶螟感染的Wolbachia类型较为单一, 这也是我国有关稻纵卷叶螟内共生菌Wolbachia的首次研究报道。     

Evaluation of the denitrifying microbiota of anoxic reactors

Removal of inorganic nitrogen compounds from wastewaters can be accomplished by a combination of the biological processes of nitrification and denitrification. The information on the microbiota present in denitrifying reactors is still scarce. In the present work the evaluation of the denitrifying microbiota of different reactor sludges was performed by specific activity measurements and MPN count of denitrifiers. We also present the isolation and physiological and phylogenetic characterisation of denitrifying bacteria from the anoxic reactor of a combined system treating landfill leachate. Specific denitrifying activity measurements were faster to perform and more reliable than MPN enumerations. 16S rDNA characterisation of the isolates showed that they belonged to the genera Thauera, Acidovorax and Alcaligenes and were closely related to microorganisms retrieved from ecosystems rich in recalcitrant compounds. Two of the isolates could grow on aromatic compounds as sole carbon source.     

Cell death induced by Pteris semipinnata L. is associated with p53 and oxidant stress in gastric cancer cells

In this study, we demonstrated that Ent-11alpha-hydroxy-15-oxo-kaur-16-en-19-oic-acid (5F) had stronger cytotoxicity against MKN-45, a gastric cancer cell line bearing wild-type p53 than MKN-28, another gastric cancer cell line containing missense mutation in p53. The rapid increase of ROS level was involved in the mechanism of cytotoxicity. Classical features of apoptosis induced by 5F were observed in MKN-45 cells only or more significant in MKN-45 cells than MKN-28 cells. Translocation of Bax from cytosol to mitochondria, reduction of delta psi m and DNA fragmentation were induced by 5F in the p53-dependent manner. We conclude that the expression of Bax and its downstream molecules requires the presentation of a wild-type p53 in the cells treated by 5F.     

Mitogenomic phylogeny of the Percichthyidae and Centrarchiformes (Percomorphaceae): comparison with recent nuclear gene-based studies and simultaneous analysis

Delineation of the fish family Percichthyidae (Percomorphaceae) has a long and convoluted history, with recent morphological-based studies restricting species members to South American and Australian freshwater and catadromous temperate perches. Four recent nuclear gene-based phylogenetic studies, however, found that the Percichthyidae was not monophyletic and was nested within a newly discovered inter-familial clade of Percomorphaceae, the Centrarchiformes, which comprises the Centrarchidae and 12 other families. Here, we reexamined the systematics of the Percichthyidae and Centrarchiformes based on new mitogenomic information. Our mitogenomic results are globally congruent with the recent nuclear gene-based studies although the overall amount of phylogenetic signal of the mitogenome is lower. They do not support the monophyly of the Percichthyidae, because the catadromous genus Percalates is not exclusively related to the freshwater percichthyids. The Percichthyidae (minus Percalates) and Percalates belong to a larger clade, equivalent to the Centrarchiformes, but their respective sister groups are unresolved. Because all recent analyses recover a monophyletic Centrarchiformes but with substantially different intra-relationships, we performed a simultaneous analysis for a character set combining the mitogenome and 19 nuclear genes previously published, for 22 centrarchiform taxa. This analysis furthermore indicates that the Centrarchiformes are divided into three lineages and the superfamily Cirrhitoidea is monophyletic as well as the temperate and freshwater centrarchiform perch-like fishes. It also clarifies some of the relationships within the freshwater Percichthyidae.     

TWO DIFFERENT SPECIES OF EUGLENA,E. GENICULATA AND E. MYXOCYLINDRACEA (EUGLENOPHYCEAE), ARE VIRTUALLY GENETICALLY AND MORPHOLOGICALLY IDENTICAL1

We investigated the similarity of a single Euglena myxocylindracea strain, isolated originally by Bold and MacEntee, to several Euglena geniculata strains on both morphological and DNA levels. We found the three DNA stretches, consisting of fragments coding for the parts of cytoplasmic and chloroplast small subunit rRNA, and the internal transcribed spacer (ITS2) of cytoplasmic rDNA, with the combined length of 4332 nucleotides, are identical in E. myxocylindracea and E. geniculata, strain SAG 1224‐4b. Morphological differences between E. myxocylindracea and any E. geniculata strain examined were well within the range of E. geniculata variability as well. The only difference behind the distinction of E. myxocylindracea from E. geniculata is the presence of the second chloroplast in the latter. However, we were able to induce the appearance of the second chloroplast in the cells of E. myxocylindracea and its disappearance in the cells of E. geniculata by changing the composition of the culture media. We therefore conclude that E. myxocylindracea Bold and MacEntee should be regarded as an environmental form of E. geniculata Dujardin. For the first time the morphology of E. geniculata chloroplasts was shown as revealed by confocal laser microscopy.     

南海野生斑节对虾的线粒体16S rRNA基因序列单倍型分析

采用聚合酶链式反应(PCR)技术对我国南海海域5个地点(三亚、深圳、阳江、湛江、北海)的野生斑节对虾100个个体的mtDNA 16S rRNA序列进行扩增,扩增产物经纯化后进行测序.用Clustal_X排序软件对所得的100个mtDNA 16S rRNA序列进行比对.通过ARLEQUIN软件对所得100个mtDNA 16S rRNA序列进行比较分析,共检测出28个变异位点,19种单倍型.19单倍型序列的碱基组成显示出较高的A T比例(69.0%).19种单倍型序列的遗传距离在0.002～0.033.根据构建的单倍型进化关系网,5个地点群体中的单倍型呈现一种混杂的分布格局.此外,根据单倍型在5个地点群体出现的频率和单倍型进化关系网,单倍型7是最为原始的单倍型,其他18种单倍型均起源于单倍型7.