丹桂和籽银桂花芽分化的研究

采用石蜡切片技术, 对不育的丹桂(Osmanthus fragrans ‘Dangui’ )和可育的籽银桂(Osmanthus fragrans ‘Ziyingui’)花芽分化的过程进行了研究。结果表明, 桂花(Osmanthus fragrans Lour.)花芽形态分化可分为花芽分化初始期、总苞分化期、花原基分化期、顶花花被分化期、雄蕊分化期和雌蕊分化期6个阶段。雄蕊的发育在丹桂和籽银桂之间基本没有区别, 都能形成完整的花粉囊和成熟的花粉粒。但是, 雌蕊的发育在可育的籽银桂与不育的丹桂之间存在明显差异。根据花芽分化的过程证明, 丹桂的不育是由于雌蕊发育不正常导致的。     

Comparison between gene expression of conidia and germinating phase in Trichophyton rubrum

Trichophyton rubrum is a dominating superficial dermatophyte, whose conidial germination is correlated to pathopoiesis and a highly important developmental process. To investigate the changes of physiology, biochemistry and cytology during the germination, we selected 3364 function identified ESTs from T. rubrum cDNA library to construct cDNA microarrays, and compared the gene expression levels of conidia and germinating phase. Data analysis indicated that 335 genes were up-regulated during the germination, which mainly encoded translated, modified proteins and structural proteins. The constituents of cell wall and cell membrane were synthetized abundantly, suggesting that they are the foundation of cell morphogenesis. The ingredients of the two-component signal transduction system were up-regulated, presuming that they were important for the conidial germination. Genes of various metabolic pathways were expressed prosperously, especially the genes that participated in glycolysis and oxidative phosphorylation were up-regulated on the whole, demonstrating that in the environment with sufficient oxygen and glucose, conidia obtained energy through aerobic respiration. This paper provides important clues which are helpful to understanding the changes in gene expression, signal conduction and metabolism characteristics during T. rubrum conidial germination, and possess significant meaning to the study of other superficial dermatophytes. Supported by the National High Technology Research and Development Program of China (Grant No. 2001AA223021) and National Key Technologies R&D Programme (Grant No. 2002BA711A14)     

The Shanita fauna (Permian foraminifera) from Baoshan area, western Yunnan Province, China

Studies in the past decade have proven the Shanita fauna to be an excellent marker of the northern peri-Gondwana tectonic blocks.Thus,a study of the Shanita fauna from the Baoshan area in western Yunnan Province,China,could provide pivotal paleontological evidence for the paleogeographic reconstruction of the Baoshan block.We systematically analyzed the composition and the age of the Shanita fauna from the Permian Da'aozi Formation in Woniusi Section of the Baoshan area.Results suggested that the characteristic genera Shanita and Hemigordiopsis in this fauna comprised eight species (including two new species),and ten genera of other nonfusulinid foraminifera were also recognized from this fauna.Further comparative study showed that the Shanita fauna from the Baoshan area were probably late Maokouan (Lengwuan)to Wuchiapingian in age.In general composition,this fauna is comparable to those Shanita faunas from Shan State of Burma,Peninsular Thailand,and Nagri of Tibet,China.However,the relatively low generic diversity and occurrence of some endemic species,as well as the absence of fusulinids,indicate certain regional features of the Shanita fauna from the Baoshan area.     

FRET-based biosensors for protein kinases: illuminating the kinome

Protein kinases are crucial components of intracellular signaling pathways which transmit signals by phosphorylation of downstream targets, altering their function. Efficient signal transduction requires precise kinase regulation within specific biological contexts, making tools that allow study of their dynamics in situ critical for understanding kinase function. Highlighted in this article is the design of genetically-encodable, FRET-based kinase biosensors with examples of their implementation to study kinase regulation in live biological contexts with high spatial and temporal resolution.     

1H, 13C, and 15N resonance assignments of human phosphohistidine phosphatase 1 (PHPT1)

Phosphohistidine phosphatase 1 (PHPT1) is the first protein histidine phosphatase identified in vertebrates. The NMR assignments of human PHPT1 are essential for solution structure determination and NMR study of the protein interactions of PHPT1 with its potential substrates.     

Transducing the Hedgehog signal across the plasma membrane

Cell signaling mediated by the Hedgehog (Hh) family of secreted proteins is essential for metazoan development and its malfunction causes congenital disorders and cancer. The seven-transmembrane protein Smoothened (Smo) transduces the Hh signal across the plasma membrane in both vertebrates and invertebrates but the underlying mechanisms remain ill defined. In Drosophila, Hh induces phosphorylation of Smo at multiple sites by PKA and CK1, leading to its cell surface accumulation and activation. Recently, we have obtained evidence that Hh-induced phosphorylation promotes Smo activity by inducing a conformational switch and dimerization of its carboxy-terminal cytoplasmic tail (C-tail). Furthermore, we provided evidence that a similar mechanism regulates mammalian Smo. We discuss how Smo conformational change regulates the intracellular signaling complex and how Smo transduces the graded Hh signaling activities through different conformational states.     

Development of a RP-HPLC method for screening potentially counterfeit anti-diabetic drugs

Pharmaceutical counterfeiting is becoming a serious problem in the world, especially in developing countries including China. Herein an isocratic reversed-phase high performance liquid chromatography (RP-HPLC) method was developed for screening counterfeit medicines and adulterated dietary supplement products. The developed method could be employed to separate and determine simultaneously six anti-diabetic drugs (glipizide, gliclazide, glibenclamide, glimepiride, gliquidone, repaglinide) on an isocratic solvent system using an Alltima C18 column (5 microm, 150 mmx4.6 mm) with an isocratic mobile phase of methanol-phosphate buffer (pH 3.0; 0.01 mol/L) (70:30, v/v), at a flow rate of 1.0 mL/min and at a wavelength of 230 nm. The proposed method was successfully applied to the analysis of medicinal and dietary supplement samples purchased from the local market in China.     

Membrane subproteomic analysis of Mycobacterium bovis bacillus Calmette-Guérin

Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccine has been known for a long time to prevent tuberculosis (TB) worldwide since 1921. Nonetheless, we know little about BCG membrane proteome. In the present study, we utilized alkaline incubation and Triton X-114-based methods to enrich BCG membrane proteins and subsequently digested them using proteolytic enzyme. The recovered peptides were further separated by 2-D LC and identified by ESI-MS/MS. As a result, total 474 proteins were identified, including 78 integral membrane proteins (IMPs). Notably, 18 BCG IMPs were described for the first time in mycobacterium. Further analysis of the 78 IMPs indicated that the theoretical molecular mass distribution of them ranged from 8.06 to 167.86 kDa and pI scores ranged from 4.40 to 11.60. Functional classification revealed that a large proportion of the identified IMPs (67.9%, 53 out of 78) were involved in cell wall and cell processes functional group. In conclusion, here we reported a comprehensive profile of the BCG membrane subproteome. The present investigation may allow the identification of some valuable vaccine and drug target candidates and thus provide basement for future designing of preventive, diagnostic, and therapeutic strategies against TB.     

Characterization and fine mapping of <Emphasis Type="Italic">RppQ</Emphasis>, a resistance gene to southern corn rust in maize

Southern corn rust (SCR) is a fungal disease caused by Puccinia polysora Underw, which can infect maize and may result in substantial yield losses in maize production. The maize inbred line Qi319 carries the SCR resistance gene RppQ. In order to identify molecular markers linked to the RppQ gene, several techniques were utilized including random amplified polymorphic DNA (RAPD), simple sequence repeat (SSR), and amplified fragment length polymorphism (AFLP). In addition, sequence characterized amplified region (SCAR) techniques combined with bulked segregant analysis (BSA) were used. Seven RAPD markers, eight SSR markers, and sixty-three AFLP primer combinations amplified polymorphisms between two parents and two bulk populations. A large F₂ population was used for genetic analysis and for fine mapping of the RppQ gene region. One AFLP polymorphic band, M-CAA/E-AGC₃₂₄, was converted to a SCAR marker, MA7, which was mapped to a position 0.46 cM from RppQ. Finally, the RppQ gene was mapped between the SCAR marker MA7 and the AFLP marker M-CCG/E-AGA₁₅₇ with distances of 0.46 and 1.71 cM, respectively.     

Tissue expression and cellular localization of phospholipid hydroperoxide glutathione peroxidase (PHGPx) mRNA in male mice

Phospholipid hydroperoxide glutathione peroxidase (PHGPx) is an ubiquitous antioxidant enzyme, but the exact expression pattern in mammalian tissues is still unknown. The expression and cellular localization of PHGPx mRNA were examined in male mice using real time-polymerase chain reaction and in situ hybridization techniques. The rank order of PHGPx mRNA expression across tissues exhibiting substantial levels of expression was:testes ≫ heart > cerebrum ≥ ileum > stomach = liver = jejunum ≥ epididymis. In testes, PHGPx mRNA was highly expressed in spermiogenic cells and Leydig cells. The signal was also expressed in the molecular layer, Purkinje cell layer, and white matter of cerebellum, the pituicytes of neurohypophysis, the parafollicular cells and follicular basement membrane of thyroid, the exocrine portion of pancreas, the tubular epithelium of kidney, the smooth muscle cells of arteries, and the red pulp of spleen. In the gastrointestinal tract, PHGPx mRNA expression was mainly observed in the keratinized surface epithelium of forestomach, the submucosal glands and serosa layers, and further the Paneth cells of intestines. PHGPx mRNA appeared to be ubiquitously expressed in the parenchyma of heart, liver, and lung. These results indicate that PHGPx exhibits a cell- and tissue-specific expression pattern in mice.