香果树根萌苗生长特性及影响因子分析

香果树(Emmenopterys henryi)为我国Ⅱ级野生保护植物,由于生境遭到破坏、过度开发利用以及种群自然更新能力差等原因,导致自然环境下香果树种群数量迅速衰减。运用方差分析、多重比较、主成分分析等方法,对自然环境下香果树种群的根萌苗生长状况及其主要影响因子进行了研究。结果表明:香果树根萌苗的数量随着苗龄的增长逐渐减少,1a根萌苗的死亡率最高;苗高和基径均随苗龄的增大呈指数增长;香果树根萌苗主要生长在母树东南方120°~150°(以正北方为0°按顺时针方向旋转,下同)位置、距母树树干2 m以内及直径2 cm、长度30 cm的露根上;根萌苗苗高受母树方位影响较小,受露根直径、露根长度以及与母树间距离的影响稍大;母树南向(168.75°)根萌苗的基径显著大于其它方向的根萌苗基径;与北向和南向相比,母树东向和西向根萌苗的冠幅较大;根萌苗苗高、基径和冠幅等形态指标均随着与母树树干间距离的增加而降低,但随着露根直径的增加各形态指标均呈先升高后降低的趋势(露根直径6.5 cm时苗高和基径达到最大值),随着露根长度的增加各形态指标呈先降低后升高的趋势;与树冠内根萌苗相比,香果树母树树冠外根萌苗的死亡率较高。主成分分析结果表明,随着林内光照条件的改善、土壤中有机质含量的增加、砾石覆盖率的增加以及适度的人为干扰均有利于香果树根萌苗的生长。因此,减小林冠郁闭度、增加人工抚育措施对维持香果树的种群发展、实现其种群自然更新具有重要作用。     

再治疗根管内三种细菌检出及其与临床表征关系的分析研究

目的检测根管再治疗患者根管内白色假丝酵母菌、变形链球菌、古细菌三种细菌的检出率情况,并分析再治疗患者根管内白色假丝酵母菌、变形链球菌、古细菌三种细菌与临床症状之间的关系。方法临床选取89名根管再治疗患者,通过记录患牙的临床相关体征、症状等信息,去除根管内原有充填物,插入无菌纸尖60 s,与H锉刮取物一同放入EP管中,提取基因组DNA,通过PCR反应检测白色假丝酵母菌、变形链球菌、古细菌三种细菌的16S RNA,检测根管再治疗患者根管内白色假丝酵母菌、变形链球菌、古细菌三种细菌的检出率情况,并分析再治疗患者根管内白色假丝酵母菌、变形链球菌、古细菌三种细菌与临床症状之间的关系。结果根管再治疗患者根管内白色假丝酵母菌、变形链球菌、古细菌三种细菌的检出率分别为31.46%、29.21%、19.10%。在临床症状中叩痛病例组中的变形链球菌检出率高于无叩痛病例组(P0.05)。结论根管再治疗患者根管内变形链球菌的检出与临床症状中的叩痛密切相关,与根尖周破坏呈正相关。根管再治疗患者根管可以检测出白色假丝酵母菌、变形链球菌、古细菌三种细菌。     

中国酶工程的兴旺与崛起

酶工程是生物工程的重要组成部分,工业生物催化技术被认为是继医药、农业之后的第三个浪潮。在25年中,中国在酶工程领域研究中取得很大进展,本综述集中介绍在中国酶工程会议上,酶的基因工程、酶的蛋白质工程、生物合成、微生物转化和生物传感器方面的成果和我国酶制剂工业的进展。     

Ultrasensitive proteome analysis using paramagnetic bead technology

In order to obtain a systems‐level understanding of a complex biological system, detailed proteome information is essential. Despite great progress in proteomics technologies, thorough interrogation of the proteome from quantity‐limited biological samples is hampered by inefficiencies during processing. To address these challenges, here we introduce a novel protocol using paramagnetic beads, termed Single‐Pot Solid‐Phase‐enhanced Sample Preparation (SP3). SP3 provides a rapid and unbiased means of proteomic sample preparation in a single tube that facilitates ultrasensitive analysis by outperforming existing protocols in terms of efficiency, scalability, speed, throughput, and flexibility. To illustrate these benefits, characterization of 1,000 HeLa cells and single Drosophila embryos is used to establish that SP3 provides an enhanced platform for profiling proteomes derived from sub‐microgram amounts of material. These data present a first view of developmental stage‐specific proteome dynamics in Drosophila at a single‐embryo resolution, permitting characterization of inter‐individual expression variation. Together, the findings of this work position SP3 as a superior protocol that facilitates exciting new directions in multiple areas of proteomics ranging from developmental biology to clinical applications.     

Role of tertiary structures on the Root effect in fish hemoglobins

Many fish hemoglobins exhibit a marked dependence of oxygen affinity and cooperativity on proton concentration, called Root effect. Both tertiary and quaternary effects have been evoked to explain the allosteric regulation brought about by protons in fish hemoglobins. However, no general rules have emerged so far. We carried out a complementary crystallographic and microspectroscopic characterization of ligand binding to crystals of deoxy-hemoglobin from the Antarctic fish Trematomus bernacchii (HbTb) at pH 6.2 and pH 8.4. At low pH ligation has negligible structural effects, correlating with low affinity and absence of cooperativity in oxygen binding. At high pH, ligation causes significant changes at the tertiary structural level, while preserving structural markers of the T state. These changes mainly consist in a marked displacement of the position of the switch region CD corner towards an R-like position. The functional data on T-state crystals validate the relevance of the crystallographic observations, revealing that, differently from mammalian Hbs, in HbTb a significant degree of cooperativity in oxygen binding is due to tertiary conformational changes, in the absence of the T–R quaternary transition. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.     

A high‐throughput sample preparation method for cellular proteomics using 96‐well filter plates

A high‐throughput sample preparation protocol based on the use of 96‐well molecular weight cutoff (MWCO) filter plates was developed for shotgun proteomics of cell lysates. All sample preparation steps, including cell lysis, buffer exchange, protein denaturation, reduction, alkylation and proteolytic digestion are performed in a 96‐well plate format, making the platform extremely well suited for processing large numbers of samples and directly compatible with functional assays for cellular proteomics. In addition, the usage of a single plate for all sample preparation steps following cell lysis reduces potential samples losses and allows for automation. The MWCO filter also enables sample concentration, thereby increasing the overall sensitivity, and implementation of washing steps involving organic solvents, for example, to remove cell membranes constituents. The optimized protocol allowed for higher throughput with improved sensitivity in terms of the number of identified cellular proteins when compared to an established protocol employing gel‐filtration columns.     

Thymoquinone causes multiple effects,including cell death,on dividing plant cells

Thymoquinone (TQ) is a major constituent of Nigella sativa oil with reported anti-oxidative activity and anti-inflammatory activity in animal cells. It also inhibits proliferation and induces programmed cell death (apoptosis) in human skin cancer cells. The present study sought to detect the influence of TQ on dividing cells of three plant systems and on expression of Bcl2-associated athanogene-like (BAG-like) genes that might be involved during the process of cell death. BAG genes are known for the regulation of diverse physiological processes in animals, including apoptosis, tumorigenesis, stress responses, and cell division. Synthetic TQ at 0.1 mg/mL greatly reduced wheat seed germination rate, whereas 0.2 mg/mL completely inhibited germination. An Evans blue assay revealed moderate cell death in the meristematic zone of Glycine max roots after 1 h of TQ treatment (0.2 mg/mL), with severe cell death occurring in this zone after 2 h of treatment. Light microscopy of TQ-treated (0.2 mg/mL) onion hairy root tips for 1 h revealed anti-mitotic activity and also cell death-associated changes, including nuclear membrane disruption and nuclear fragmentation. Transmission electron microscopy of TQ-treated cells (0.2 mg/mL) for 1 h revealed shrinkage of the plasma membrane, leakage of cell lysate, degradation of cell walls, enlargement of vacuoles and condensation of nuclei. Expression of one BAG-like gene, previously associated with cell death, was induced 20 min after TQ treatment in Glycine max root tip cells. Thus, TQ has multiple effects, including cell death, on dividing plant cells and plants may serve as a useful system to further investigate the mechanisms underlying the response of eukaryotic cells to TQ.     

Concepts and strategies of soybean seed proteomics using the shotgun proteomics approach

ABSTRACT

Introduction: The last decade has yielded significant developments in the field of proteomics, especially in mass spectrometry (MS) and data analysis tools. In particular, a shift from gel-based to MS-based proteomics has been observed, thereby providing a platform with which to construct proteome atlases for all life forms. Nevertheless, the analysis of plant proteomes, especially those of samples that contain high-abundance proteins (HAPs), such as soybean seeds, remains challenging.

Areas covered: Here, we review recent progress in soybean seed proteomics and highlight advances in HAPs depletion methods and peptide pre-fractionation, identification, and quantification methods. We also suggest a pipeline for future proteomic analysis, in order to increase the dynamic coverage of the soybean seed proteome.

Expert opinion: Because HAPs limit the dynamic resolution of the soybean seed proteome, the depletion of HAPs is a prerequisite of high-throughput proteome analysis, and owing to the use of two-dimensional gel electrophoresis-based proteomic approaches, few soybean seed proteins have been identified or characterized. Recent advances in proteomic technologies, which have significantly increased the proteome coverage of other plants, could be used to overcome the current complexity and limitation of soybean seed proteomics.