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.     

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。     

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.     

Topoisomerase I‐Mediated Antiproliferative Activity of 10‐Substituted and 12‐Substituted Homocamptothecins

Homocamptothecin (hCPT) is an E‐ring modified camptothecin (CPT) analogue, which showed pronounced inhibitory activity of topoisomerase I. In search of novel hCPT‐type anticancer agents, two series of hCPT derivatives were synthesized and evaluated in vitro against three human tumor cell lines. The results indicated that the 10‐substituted hCPT derivatives had a considerably higher cytotoxic activity than the 12‐substituted ones. Among the 10‐substituted compounds, 8a, 8b, 9b , and 9i showed an equivalent or even more potent activity than the positive control drug topotecan against the lung cancer cell line A‐549. Moreover, the hCPT analogues 8a and 8b exhibited a higher topoisomerase I inhibitory activity than CPT at a concentration of 100 μM .     

Use of DNA methylation for cancer detection and molecular classification

Conjugation of the methyl group at the fifth carbon of cytosines within the palindromic dinucleotide 5'-CpG-3' sequence (DNA methylation) is the best studied epigenetic mechanism, which acts together with other epigenetic entities: histone modification, chromatin remodeling and microRNAs to shape the chromatin structure of DNA according to its functional state. The cancer genome is frequently characterized by hypermethylation of specific genes concurrently with an overall decrease in the level of 5-methyl cytosine, the pathological implication of which to the cancerous state has been well established. While the latest genome-wide technologies have been applied to classify and interpret the epigenetic layer of gene regulation in the physiological and disease states, the epigenetic testing has also been seriously explored in clinical practice for early detection, refining tumor staging and predicting disease recurrence. This critique reviews the latest research findings on the use of DNA methylation in cancer diagnosis, prognosis and staging/classification.