Observations on the division characterization of diploid nuclear in <Emphasis Type="Italic">Porphyra</Emphasis> (Bangiales,Rhodophyta)

Nuclear divisions of carpospores, conchocelis and conchospores of Porphyra yezoensis, P. haitanensis, P. katadai var. hemiphylla and P. oligospermatangia from China were investigated. The observations showed diploid chromosome numbers of 2n = 6 for P. yezoensis and P. oligospermatangia, and 2n = 10 for P. haitanensis and P. katadai var. hemiphylla. For all four species, somatic pairing of chromosome sets was observed in late prophase. Sister chromosomes separated at anaphase as mitosis took place in carpospores, conchocelis filamentous cells, conchosporangial branch cells and sporangial cells (conchospore formation). Chromosome configurations of tetrad and ring-shaped in conchospore germination were observed, demonstrating the occurrence of meiosis. The characteristics of diploid nuclear division in 2n = 6 species are the same as those of 2n = 10 species. The influence of somatic pairing on nuclear division of diploid cells in Porphyra was discussed.     

Association of Plasma IL-6 and Hsp70 with HRV at Different Levels of PAHs Metabolites

Background

Exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with reduced heart rate variability (HRV), a strong predictor of cardiovascular diseases, but the mechanism is not well understood.

Objectives

We hypothesized that PAHs might induce systemic inflammation and stress response, contributing to altered cardiac autonomic function.

Methods

HRV indices were measured using a 3-channel digital Holter monitor in 800 coke oven workers. Plasma levels of interleukin-6 (IL-6) and heat shock protein 70 (Hsp70) were determined using ELISA. Twelve urinary PAHs metabolites (OH-PAHs) were measured by gas chromatography-mass spectrometry.

Results

We found that significant dose-dependent relationships between four urinary OH-PAHs and IL-6 (all P _trend<0.05); and an increase in quartiles of IL-6 was significantly associated with a decrease in total power (TP) and low frequency (LF) (P _trend = 0.014 and 0.006, respectively). In particular, elevated IL-6 was associated in a dose-dependent manner with decreased TP and LF in the high-PAHs metabolites groups (all P _trend<0.05), but not in the low-PAHs metabolites groups. No significant association between Hsp70 and HRV in total population was found after multivariate adjustment. However, increased Hsp70 was significantly associated with elevated standard deviation of NN intervals (SDNN), TP and LF in the low-PAHs metabolites groups (all P _trend<0.05). We also observed that both IL-6 and Hsp70 significantly interacted with multiple PAHs metabolites in relation to HRV.

Conclusions

In coke oven workers, increased IL-6 was associated with a dose-response decreased HRV in the high-PAHs metabolites groups, whereas increase of Hsp70 can result in significant dose-related increase in HRV in the low-PAHs metabolites groups.     

蛇足石杉内生真菌Shiraia sp. Slf14中赖氨酸脱羧酶基因的克隆、表达及功能

【目的】阿尔茨海默症治疗药物石杉碱甲(Huperzine A,Hup A)的生物合成途径起始于赖氨酸脱羧酶(Lysine decarboxylase,LDC)。本研究克隆及表达了来源于产Hup A的植物内生真菌的LDC基因,并研究了其功能。【方法】采用RT-PCR扩增法,从一株产Hup A的蛇足石杉内生真菌Shiraia sp.Slf14获得LDC基因,构建表达质粒p ET-22b-LDC与p ET-32a-LDC,转化感受态细胞E.coli BL21,加入IPTG至终浓度为1×10~(–3) mol/L,于24°C、200 r/min培养8 h,诱导表达LDC蛋白质;通过Ni~(2+)金属亲和层析纯化重组LDC并建立酶促反应体系,利用TLC检测了LDC催化活性。利用生物信息学软件分析了LDC的理化性质及蛋白质的空间结构。【结果】成功克隆并异源表达出重组蛋白LDC与Trx-LDC,经SDS-PAGE电泳鉴定分子量分别为24.4 k Da和42.7 k Da,与预计大小相符。TLC结果表明LDC与Trx-LDC均具有赖氨酸脱羧酶活性。【结论】本研究从产Hup A的蛇足石杉内生真菌Shiraia sp.Slf14中成功克隆到LDC基因并进行了异源表达,检测到了其催化活性,为丰富LDC分子信息及阐明内生真菌中Hup A生物合成机制提供参考数据。     

陕南早寒武世ANABARITES壳体内部结构及亲缘关系探讨

陕南灯影组宽川铺段的小壳化石具完好的三维保存方式。Anabarites是三辐射对称、单管底栖群居生物,亲缘关系不明。作者通过对陕南宁强下寒武统宽川铺段进行数次系统采样,经过对样品的醋酸溶蚀处理和电子扫描电镜照像后,发现Anabarites壳体内部具螺旋状微结构;经测试分析后认为该结构可能与中槽的深浅成正相关,两者的形成可能与微环境中水体的变化有关。探讨其可能的亲缘关系及其演化序列。     

虫害马尾松(Pinus massoniana Lamb)邻枝针叶挥发物及其内源茉莉酸甲酯的快速变化

对盆栽马尾松针叶进行接虫咬食危害处理后,通过TCT-GC/MS分析了同一株受害枝相邻的健康枝针叶挥发物的成分及相对含量的时序变化。结果表明：萜烯类化合物是邻枝针叶挥发物的主要成分,其次是含氧化合物、含氮化合物等。与对照相比,多数挥发物的相对含量1h略高于对照,2h维持较高水平。同时,用GC/MS分析了邻枝针叶不同时间序列中茉莉酸甲酯的含量,结果表明：虫害马尾松邻枝针叶1h茉莉酸甲酯含量就有所升高,2h显著高于对照,是对照的近1倍。证明马尾松受到虫害后,启动了体内的防御系统,并诱导邻枝产生抗性。     

A hybrid model for erythrocyte membrane: a single unit of protein network coupled with lipid bilayer

To investigate the nanomechanics of the erythrocyte membrane we developed a hybrid model that couples the actin-spectrin network to the lipid bilayer. This model features a Fourier space Brownian dynamics model of the bilayer, a Brownian dynamics model of the actin protofilament, and a modified wormlike-chain model of the spectrin (including a cable-dynamics model to predict the oscillation in tension). This model enables us to predict the nanomechanics of single or multiple units of the protein network, the lipid bilayer, and the effect of their interactions. The present work is focused on the attitude of the actin protofilament at the equilibrium states coupled with the elevations of the lipid bilayer through their primary linkage at the suspension complex in deformations. Two different actin-spectrin junctions are considered at the junctional complex. With a point-attachment junction, large pitch angles and bifurcation of yaw angles are predicted. Thermal fluctuations at bifurcation may lead to mode-switching, which may affect the network and the physiological performance of the membrane. In contrast, with a wrap-around junction, pitch angles remain small, and the occurrence of bifurcation is greatly reduced. These simulations suggest the importance of three-dimensional molecular junctions and the lipid bilayer/protein network coupling on cell membrane mechanics.     

Quantitative response of cell growth and Tuber polysaccharides biosynthesis by medicinal mushroom Chinese truffle Tuber sinense to metal ion in culture medium

During the submerged fermentation of medicinal mushroom Chinese truffle Tuber sinense, there was no significant effect of metal ion on the cell growth and the production of intracellular polysaccharides, while metal ion and its concentration significantly affected the production of extracellular polysaccharides (EPS). By using the approach of "one-variable-at-a-time", 50 mM Mg2+ was identified to be the most favorable for EPS production, and the next was 10 mM K+. A mathematical model, constructed by response surface methodology combination with full factorial design, was applied to study the synergic effect of Mg2+ and K+. EPS production reached its peak value of 5.86 g/L under their optimal combination of 30 mM Mg2+ and 5 mM K+ predicted by the model, which was higher by 130.7% compared with the basal fermentation medium without metal ion. The validation experiment showed the experimental values agreed with the predicted values well. EPS production obtained in this work was the highest reported in the culture of T. sinense.