常规石蜡切片方法的改良

针对传统石蜡切片方法中的缺陷,对制片方法进行了相应的改良。总结了切片制作过程中可能存在的问题以及处理对策;提出了一些能缩短实验周期,解决实验有毒物质二甲苯污染的方案。结合教学实践发现改良方案有助于提高石蜡切片的质量。     

黄梁木维管组织细胞激光显微切割技术体系建立

黄梁木是华南地区重要的速生用材树种,其快速的次生生长主要取决于包括形成层细胞在内的维管组织细胞的发育进程.为了精准获取维管组织形成层细胞与高质量RNA,该研究以黄梁木幼苗为材料,通过石蜡切片与激光显微切割(LMD)结合的方法,成功获得形成层、木质部和韧皮部细胞.结果表明:优化石蜡切片流程,以卡诺/丙酮作为固定剂(丙酮浓...     

Study on the role of Nocardia farcinica in enhancing the flow rate of crude oil

Microbial degradation of paraffin wax is an efficient method of removing wax deposition from pipelines and enhancing the flow rate of crude oil. The present study was carried out to isolate a potential paraffin-degrading organism from oil wells of Gujarat. Screening for bacteria-utilizing paraffin wax as the sole source of carbon was carried out using 2,6-dichlorophenol indophenol (DCPIP) dye as redox indicator. The selected organism was identified as Nocardia farcinica by 16S rRNA sequencing. Nocardia farcinica showed 100% degradation of heneicosane, 65.99% degradation of docosane, and 50.59% degradation of tricosane, the major components of paraffin wax, in 8 days, which was observed by gas chromatography. Eicosane (86%) and heneicosane (80%) were utilized more by the selected organism compared with octacosane (61%) and triacontane (58%) (DCPIP dye method). Gas chromatographic analysis revealed that the selected organism degraded 50% of paraffin crude oil in 10 days. To determine the ability of the selected organism to enhance flow rate, parameters such as viscosity (cps), surface tension (d/cm²), pour point (°C), and flow rate (min/2 ml) were determined, and the result showed significant reduction in all the parameters after the addition of Nocardia farcinica. The viscosity and surface tension of crude oil were reduced by 22 and 6.30 points, respectively, after the addition of Nocardia farcinica. Pour point and flow rate were reduced by 2 and 11 points, respectively, when compared with control. The above findings indicate that Nocardia farcinica isolated from crude oil plays a major role in enhancing the flow rate of crude oil.     

The use of histology in the study of plant tissue culture systems—Some practical comments

Summary Histological methods have contributed significantly to our understanding of in vitro culture systems. A good histological study based on anatomical and histochemical changes provides insight into cellular processes and provides clues that allow for the proposal of hypotheses for further experimentation. This article serves to draw attention to the use of a histological approach to one’s experimental system. Some of the common mistakes in the handling and processing of explants are discussed. A protocol for the plastic embedding method is detailed.     

半边莲营养器官结构与生态环境的关系

利用石蜡切片和光学显微镜,对半边莲的营养器官进行形态解剖学研究。结果表明:半边莲根和茎的次生结构不发达;地上茎表现为根的特征:茎皮层所占比例较大,茎中有明显的内皮层,内皮层上具凯氏带;根的皮层和茎的髓具通气组织,裂生型分泌道存在于茎的皮层;叶的气孔高于表皮,气孔只在上表皮有分布,叶尖具水孔。半边莲的形态结构特征表现出对水生生活的高度适应。对半边莲的系统位置也作了简单探讨。     

A cut-off based approach for gene expression analysis of formalin-fixed and paraffin-embedded tissue samples

Microarray analysis of formalin-fixed and paraffin-embedded (FFPE) tissue seems to be of importance for the detection of molecular marker sets in prostate cancer (PC). The compromised RNA integrity of FFPE tissue results in a high degree of variability at the probe level of microarray data as shown by degradation plot. We tested methods that reduce the variability by including all probes within 300 nucleotides, within 600 nucleotides, or up to a calculated breakpoint with reference to the 3'-end. Accepted PC pathways such as the Wnt signaling pathway could be observed to be significantly regulated within FFPE microarray datasets. The best representation of PC gene expression, as well as better comparability to meta-analysis and fresh-frozen microarray data, could be obtained with a 600-nucleotide cutoff. Beyond the specific impact for PC microarray data analysis we propose a cutoff of 600 nucleotides for samples for which the integrity of the RNA cannot be guaranteed.     

Components of the ant secretions

Studies on the chemistry of the secretions from various ant species have shown that the ants can be classified into four groups on the basis of the major component(s) in their secretions: group A, contains paraffins along with formic acid; group B, contains terpenes; group c, contains considerable amount of paraffins, terpenes and acyclic ketones; and group D, contains aromatic compounds.     

A simple method for studying whole sections of rice grain

We developed a new and simple method to collect sections of a whole brown rice kernel for investigation of histological properties. A single kernel of rice was dehydrated through a graded ethanol series, transferred to xylene, and embedded in paraffin. During sectioning of the blocks using a rotary microtome, we used a special adhesive tape to collect and place the sections on slides so they remained flat. The use of the adhesive tape technique combined with autofluorescence characteristics allowed us to visualize cell walls throughout an entire longitudinal or transverse section of a whole rice kernel. We obtained scanning electron microscopy images of the sections to determine section quality.     

Fibrinogen alpha amyloidosis: insights from proteomics

ABSTRACT

Introduction: Systemic amyloidosis is a diverse group of diseases that, although rare, pose a serious health issue and can lead to organ failure and death. Amyloid typing is essential in determining the causative protein and initiating proper treatment. Mass spectrometry-based proteomics is currently the most sensitive and accurate means of typing amyloid.

Areas covered: Amyloidosis can be systemic or localized, acquired or hereditary, and can affect any organ or tissue. Diagnosis requires biopsy, histological analysis, and typing of the causative protein to determine treatment. The kidneys are the most commonly affected organ in systemic disease. Fibrinogen alpha chain amyloidosis (AFib) is the most prevalent form of hereditary renal amyloidosis. Select mutations in the fibrinogen Aα (FGA) gene lead to AFib.

Expert commentary: Mass spectrometry is currently the most specific and sensitive method for amyloid typing. Identification of the mutated fibrinogen alpha chain can be difficult in the case of ‘private’ frameshift mutations, which dramatically change the sequences of the expressed fibrinogen alpha chain. A combination of expert pathologist review, mass spectrometry, and gene sequencing can allow for confident diagnosis and determination of the fibrinogen alpha chain mutated sequence.     

Assessment of Modeled Indoor Air Concentrations of Particulate Matter,Gaseous Pollutants,and Volatile Organic Compounds Emitted from Candles

Candle burning is regarded as an important source of airborne pollutants in indoor environments. Indoor concentrations of aldehydes, benzo(a)pyrene, sulphur dioxide (SO₂), nitrogen oxides (NO_x), and particulate matter (PM) produced from the burning of scented candles and raw materials with different melting point/oil content (50/1, 55/9, and 65/6) were predicted using a single compartment mass balance model and compared to regulatory or guideline limits. Scented candles may be responsible for indoor acrolein concentrations that could become relevant to health only in the case of chronic exposure. Indoor concentrations of fine PM and SO₂ emitted from 65/6 wax burning under worst-case environmental and behavioral conditions were greater than their respective acute guideline limits. However, other waxes had levels of PM and SO₂ well below the recommended values. Indoor concentrations of nitrogen dioxide emitted from raw wax burning should be further investigated. The degree of pureness of raw waxes significantly affected the predicted indoor concentrations of PM and SO₂. In particular, 65/6 wax was criticized for its high content of impurities.