Syphacia muris: Water permeability of eggs and its effect on hatching

As a result of a previous study, it appeared that hatching of eggs of Syphacia muris is activated by the application of heat (37 °C) or cysteine or trypsin but that these are not the essential stimuli. In the present study it has been established that exposure of eggs prior to hatching for several hours to 37 °C or cysteine or trypsin, or for 3 days to 22 °C, accelerated hatching. Pretreatment with 37 °C or cysteine or trypsin also increased permeability of the eggshell to water; however, it did not induce the operculum to open. The operculum opened only if the eggs, after pretreatment, were immersed in water. The larvae could leave the opened eggs only in water and not in any other medium such as paraffin oil. These data made it possible to distinguish between three stages in the hatching process. During Stage 1, the eggshell becomes permeable to water. This can be induced by dissolving the proteins of the eggshell in a trypsin solution or by stimulating the larvae with temperature or cysteine. The permeability of the eggshell is essential to successful hatching. In Stage 2, which occurs only in the presence of water, the larvae dissolve the chitinous seal between the operculum and the eggshell. In Stage 3 the larvae probably increase their size by water absorption and leave the eggs. In the discussion it has been proposed that all nematodes, both those hatching in the intestine and the species hatching in the open, could well have an identical hatching mechanism to the one observed in Syphacia muris.     

家蚕胚胎发育过程的组织形态显微观察

胚胎发育是动物许多重要器官与性状发育的重要时期。本文利用石蜡切片法,对家蚕的胚胎发育进行了观察,并在显微镜可见光明场下拍照记录胚胎发育的形态特殊时期及其经历的发育时间,直观地获得家蚕胚胎发育完整过程。实验完整记录了家蚕胚胎发育的5个胚胎发育时期及其相对应:卵裂与胚盘形成期、胚带形成期、器官形成期和完成期及其相对应的发育时间。为进一步研究家蚕个体发育,器官的形成与分化奠定基础。     

海桑和无瓣海桑叶片结构的比较研究

为了探讨外来植物无瓣海桑的潜在危害,采用石蜡切片法对海桑(Sonneratia caseolaris Engl.)、无瓣海桑(S.apetala B.Ham)叶片进行了解剖学研究。实验结果显示,两种植物的叶片均为等面叶;中脉维管束为周韧维管束;具4级侧脉,第1级侧脉为半周韧维管束;成熟叶片叶肉组织具发达的贮水薄壁细胞,具含单宁成分的薄壁细胞,具晶体细胞和石细胞;盐腺由表皮细胞发育而成,可分为3个发育阶段。作为外来植物的无瓣海桑,其中脉维管束具微弱形成层,叶脉维管组织比海桑更发达;贮藏组织中含单宁细胞、晶体细胞较多;栅栏组织含叶绿体多于海桑等特点,使其比海桑对环境具有更大的适应性。因此,无瓣海桑有可能成为入侵植物。     

不结球白菜雄性不育系及其保持系花药发育的细胞学观察

以不结球白菜（Brassica campestris ssp．chinensis Makino）雄性不育系及其保持系为试验材料,选择不同发育阶段的花蕾,取其花药,制成石蜡切片和超薄切片,经染色后在电子显微镜下观察。结果表明,不结球白菜雄性不育系与保持系的花药发育有明显的不同：不育系花药发育受阻于花粉母细胞分化期,形成1～3个药室,并形成正常的四分体小孢子,此时细胞组织逐步解体,形成空腔花药;最后向内皱缩;保持系花粉母细胞能形成正常的四分体,进而形成小孢子,最终形成充满正常花粉粒的花药。     

An in situ hybridization protocol for planarian embryos: monitoring myosin heavy chain gene expression

The monitoring of gene expression is fundamental for understanding developmental biology. Here we report a successful experimental protocol for in situ hybridization in both whole-mount and sectioned planarian embryos. Conventional in situ hybridization techniques in developmental biology are used on whole-mount preparations. However, given that the inherent lack of external morphological markers in planarian embryos hinders the proper interpretation of gene expression data in whole-mount preparations, here we used sectioned material. We discuss the advantages of sectioned versus whole-mount preparations, namely, better probe penetration, improved tissue preservation, and the possibility to interpret gene expression in relation to internal morphological markers such as the epidermis, the embryonic and definitive pharynges, and the gastrodermis. Optimal fixatives and embedding methods for sectioning are also discussed. A. Cardona and J. Fernández have contributed equally to this work.     

荷花“重瓣化”的花器官形态发育比较观察

荷花（Nelumbo nucifera）的花型可分5种,最原始为单瓣型,然后由单瓣演化出半重瓣、重瓣、重台和千瓣型。为了揭示荷花重瓣化的分子机理,有必要从花器官的形态发育特征探究荷花花型成因及“重瓣化”的形态发育特征。实验分别选取5种荷花花型的代表品种：‘单洒锦’（单瓣型）、‘大洒锦’（重瓣型）、‘中山红台’（重台型）、‘至尊千瓣’（全重瓣型）、‘千瓣莲’（千瓣型）为材料,进行花芽分化过程形态的石蜡切片比较观察。结果发现：花芽分化过程中5个品种的萼片原基分化期和花瓣原基分化期相似,而雄蕊和雌蕊原基发育存在明显差异：单瓣、重瓣和重台品种均有正常的雄蕊和雌蕊原基分化;全重瓣品种发育初期有雄蕊及雌蕊原基分化,但后期全部瓣化;‘千瓣莲’品种不形成雄蕊和雌蕊原基,而是直接形成2至多个“花瓣增殖中心”,并由此不断分化出细小花瓣。研究认为重瓣型荷花品种的“重瓣化”花瓣主要来源于雄蕊的向心式瓣化,其次是雌蕊瓣化,属于雌雄蕊起源。而对于‘千瓣莲’型品种,花瓣的具体来源方式、花托是否直接参与瓣化及其在重瓣化过程中的作用有待于结合分子生物学手段开展进一步研究。     

适合原位RT-PCR的石蜡切片制作方法

石蜡切片是原位RT-PCR中常用一种生物制片技术,简要阐述原位RT-PCR的原理以及适合于原位RT-PCR的石蜡切片的制作流程,对其易出现的问题和解决办法作了简要的概述。     

Integrated and convenient procedure for protein extraction from formalin‐fixed,paraffin‐embedded tissues for LC‐MS/MS analysis

Because fresh‐frozen tissue samples associated with long‐term clinical data and of rare diseases are often unobtainable at the present time, formalin‐fixed paraffin‐embedded (FFPE) tissue samples are considered a highly valuable resource for researchers. However, protein extraction from FFPE tissues faces challenges of deparaffinization and cross‐link reversion. Current procedures for protein extraction from FFPE tissue require separate steps and toxic solvents, resulting in inconvenience in protein extraction. To overcome these limitations, an integrated method was developed using nontoxic solvents in four types of FFPE tissues. The average amount of proteins from three replicates of bladder, kidney, liver, and lung FFPE tissues were 442.6, 728.9, 736.4, and 694.7 μg with CVs of 7.5, 5.8, 2.4, and 4.5%, respectively. Proteomic analysis showed that 348, 417, 607, and 304 unique proteins were identified and quantified without specification of isoform by a least two peptides from bladder, kidney, liver, and lung FFPE tissue samples, respectively. The analysis of individual protein CV demonstrated that 97–99% of the proteins were quantified with a CV ≤ 30%, verifying the reproducibility of the integrated protein extraction method. In summary, the developed method is high‐yield, reproducible, convenient, simple, low cost, nonvolatile, nonflammable, and nontoxic.     

心室肌的大体与显微的层次解剖研究

目的:通过对心室肌的大体解剖与组织学切片显示心室肌纤维的层次走向,比较心肌传统概念与心肌带理论的差异.方法:(1)应用大体解剖、组织切片HE染色、虚拟切片扫描方法显示心室肌的纤维走向及层次构造.(2)将防腐固定后的成人正常心脏顺心肌纤维方向分层解剖心肌,使之展开成带,验证心肌带理论.结果:将防腐固定的成人正常心脏经改良的解剖方法解剖,可解剖出一条完整的心肌带,分为2个环,4个段.心肌带呈螺旋走向.用大体解剖与组织切片HE染色、虚拟切片扫描显示右心室肌起始于纤维三角为一条单层肌肉带,左心室肌分为三层肌纤维起始于纤维三角与纤维环,肌纤维从纤维三角与纤维环持续由外向内转变呈现为一种交错结构,纵行的浅层心肌纤维在心尖以90°的角返回心底方向,构成深层心室肌形成肉柱,部分心肌纤维斜、横行构成中层心室肌.三者在心尖呈现出一种螺旋形结构.应用虚拟切片扫描技术能完整、清楚地显示心室肌某一切面的结构走向.结论:心肌传统理论与心肌带理论并未完全冲突,心肌带理论的降段、左室断、升段与传统理论的浅、中、深三层相对应.