崖爬藤的生态生物学特征及其扦插繁殖技术

崖爬藤为葡萄科常绿或半常绿藤本,具有重要园林绿化价值。该研究采用叶片离析法和石蜡切片法研究其叶片的形态结构。结果表明:崖爬藤平均叶面积(23.1 cm~2)较大,单位叶面积干重(4.4 mg·cm~(-2))较小,成熟叶厚约为195.5μm,栅栏组织不发达,胞间隙大。利用便携式LI-6400光合测定仪、PAM-2100荧光测定仪对崖爬藤光合生理生态指标进行研究。结果表明:其PSⅡ的最大光化学效率Fv/Fm(0.818)较高;叶片的净光合速率日变化呈单峰型,没有明显的光合午休现象,最大净光合速率Pn为3.691μmol·m~(-2)·s~(-1),出现在14:00时,变化趋势与光合有效辐射Par、大气温度T、蒸腾速率Tr、气孔导度Gs等因子相同,与胞间CO_2浓度Ci相反,同时具有较高的水分利用效率(3.056μmol·mmol~(-1))。这都显示了崖爬藤喜阴湿环境,不耐寒且具有一定的耐旱特性,适合栽植于我国温度较高的南方地区。此外,以崖爬藤1~2年生老枝和当年生嫩枝为材料,经梯度溶液IBA处理进行扦插生根实验,结果表明,崖爬藤扦插繁殖迅速,生根率较高,以当年生嫩枝不经IBA处理直接扦插为最佳。该研究结果将为崖爬藤的栽培及开发利用提供重要的理论和技术指导。     

Mcm10 deficiency causes defective-replisome-induced mutagenesis and a dependency on error-free postreplicative repair

Mcm10 is a multifunctional replication factor with reported roles in origin activation, polymerase loading, and replication fork progression. The literature supporting these variable roles is controversial, and it has been debated whether Mcm10 has an active role in elongation. Here, we provide evidence that the mcm10–1 allele confers alterations in DNA synthesis that lead to defective-replisome-induced mutagenesis (DRIM). Specifically, we observed that mcm10–1 cells exhibited elevated levels of PCNA ubiquitination and activation of the translesion polymerase, pol-ζ. Whereas translesion synthesis had no measurable impact on viability, mcm10–1 mutants also engaged in error-free postreplicative repair (PRR), and this pathway promoted survival at semi-permissive conditions. Replication gaps in mcm10–1 were likely caused by elongation defects, as dbf4–1 mutants, which are compromised for origin activation did not display any hallmarks of replication stress. Furthermore, we demonstrate that deficiencies in priming, induced by a pol1–1 mutation, also resulted in DRIM, but not in error-free PRR. Similar to mcm10–1 mutants, DRIM did not rescue the replication defect in pol1–1 cells. Thus, it appears that DRIM is not proficient to fill replication gaps in pol1–1 and mcm10–1 mutants. Moreover, the ability to correctly prime nascent DNA may be a crucial prerequisite to initiate error-free PRR.     

Imitation Switch chromatin remodeling factors and their interacting RINGLET proteins act together in controlling the plant vegetative phase in Arabidopsis

During their life cycle, flowering plants must experience a transition from vegetative to reproductive growth. Here, we report that double mutations in the Arabidopsis thaliana IMITATION SWITCH (AtISWI) genes, CHROMATIN REMODELING11 (CHR11) and CHR17, and the plant‐specific DDT‐domain containing genes, RINGLET1 (RLT1) and RLT2, resulted in plants with similar developmental defects, including the dramatically accelerated vegetative‐to‐reproductive transition. We demonstrated that AtISWI physically interacts with RLTs in preventing plants from activating the vegetative‐to‐reproductive transition early by regulating several key genes that contribute to flower timing. In particular, AtISWI and RLTs repress FT, SEP1, SEP3, FUL, and SOC1, but promote FLC in the leaf. Furthermore, AtISWI and RLTs may directly repress FT and SEP3 through associating with the FT and SEP3 loci. Our study reveals that AtISWI and RLTs represent a previously unrecognized genetic pathway that is required for the maintenance of the plant vegetative phase.     

Analyzing surface EMG signals to determine relationship between jaw imbalance and arm strength loss

ABSTRACT: BACKGROUND: This study investigated the relationship between dental occlusion and arm strength; in particular, the imbalance in the jaw can cause loss in arm strength phenomenon. One of the goals of this study was to record the maximum forces that the subjects can resist against the pull-down force on their hands while biting a spacer of adjustable height on the right or left side of the jaw. Then EMG measurement was used to determine the EMG-Force relationship of the jaw, neck and arms muscles. This gave us useful insights on the arms strength loss due to the biomechanical effects of the imbalance in the jaw mechanism. METHODS: In this study to determine the effects of the imbalance in the jaw to the strength of the arms, we conducted experiments with a pool of 20 healthy subjects of both genders. The subjects were asked to resist a pull down force applied on the contralateral arm while biting on a firm spacer using one side of the jaw. Four different muscles -- masseter muscles, deltoid muscles, bicep muscles and trapezoid muscles -- were involved. Integrated EMG (iEMG) and Higuchi fractal dimension (HFD) were used to analyze the EMG signals. RESULTS: The results showed that (1) Imbalance in the jaw causes loss of arm strength contra-laterally; (2) The loss is approximately a linear function of the height of the spacers. Moreover, the iEMG showed the intensity of muscle activities decreased when the degrees of jaw imbalance increased (spacer thickness increased). In addition, the tendency of Higuchi fractal dimension decreased for all muscles. CONCLUSIONS: This finding indicates that muscle fatigue and the decrease in muscle contraction level leads to the loss of arm strength.     

植物的隐花色素及其光信号转导

介绍了近年来植物隐花色素介导的光信号转导分子机制的研究进展.     

Complete Genome Sequences of Highly Divergent Torque Teno Virus Type II from Swine Herds

Through routine and nested PCR amplifications, four complete genome sequences of porcine Torque teno virus (TTV) type II were obtained from swine herds. By comparison with the TTV genome sequences deposited in GenBank, we found the most divergent types so far described. The level of genetic diversity between these genomes is higher than would be expected within a single virus species. A nucleotide and amino acid phylogenetic tree was constructed.     

Oxaliplatin long-circulating liposomes improved therapeutic index of colorectal carcinoma

Background  

Cytotoxic drugs are non-selective between normal and pathological tissue, and this poses a challenge regarding the strategy for treatment of tumors. To achieve sufficient antitumor activity for colorectal carcinoma, optimization of the therapeutic regimen is of great importance. We investigated the ability of oxaliplatin long-circulating liposomes (PEG-liposomal L-oHP) to provide an improved therapeutic index of colorectal carcinoma.     

Effect of Optogenetic Stimulus on the Proliferation and Cell Cycle Progression of Neural Stem Cells

Modulation of stem cell proliferation is a crucial aspect of neural developmental biology and regenerative medicine. To investigate the effect of optical stimulation on neural stem cell proliferation, cells transduced with channelrhodopsin-2 (ChR2) were used to analyze changes in cell proliferation and cell cycle distribution after light stimulation. Blue light significantly inhibited cell proliferation and affected the cell cycle, which increased the percentage of cells in G₁ phase and reduced the percentage in S phase. It is likely that the influence of blue light on cell proliferation and the cell cycle was mediated by membrane depolarization, which induced accumulation of p21 and p27 proteins. Our data provide additional specific evidence that membrane depolarization may inhibit neural stem cell proliferation.     

黔西北马缨杜鹃花红色素的毒性试验

马缨杜鹃（ＲｈｏｄｏｄｅｎｄｒｏｎｄｅｌａｖａｙｉＦｒａｎｃｈ．）是贵州省分布较广的一种植物。为提高其利用价值,对花的红色素进行了毒性试验。结果表明：急性毒性试验属实际无毒范围,Ａｍｅｓ试验,骨髓细胞微核试验和精子畸形试验均未显示诱变作用。为开发马缨杜鹃花资源提供了科学依据