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1.
A re-evaluation of the cytology of cat Pacinian corpuscles 总被引:1,自引:0,他引:1
Bryce L. Munger Yasuo Yoshida Shuichiro Hayashi Tokuji Osawa Chizuka Ide 《Cell and tissue research》1988,253(1):83-93
Summary The ultrastructure of cat mesenteric Pacinian corpuscles in cross and longitudinal sections has been examined. The terminal ends of lamellar cells of the inner core have been identified in longitudinal sections through the proximal portion of the inner core. These terminal bulbous expansions contain characteristic concentric membranes of rough endoplasmic reticulum and in some cases masses of oval membranous inclusions. The central axon as seen in cross section is oval in profile, having X-(short) and Y-(long) axes, and each axonal face is characterized by specializations of the axolemma. At the X-axis, the inner lamellae of the inner core tightly abut a smooth axolemma, with no intervening connective tissue matrix, in a manner reminiscent of a neuroepithelium. The axolemma of the Y-axis has numerous axonal spines (microspikes) that project into the cleft in the inner core. The extent of the axolemma having axonal spines can only be appreciated in longitudinal sections. The clefts contain a specialized connective tissue with elastic and collagen fibrils. The connective tissue compartment of fibers and matrix separating individual inner core lamellae is unique, in that it contains extremely thin collagen fibrils measuring approximately 15 nm in diameter. The diameter of collagen fibrils increases as the cleft is approached. Here the fibrils resemble typical endoneural collagen. 相似文献
2.
记内蒙古Juxia一新种 总被引:1,自引:1,他引:0
本文记述了在内蒙古沙拉木伦额尔登敖包地区第三系下渐新统乌兰戈楚组中发现的始巨犀的一个新种:寿氏始巨犀(Juxia shoui)。据其前臼齿及鼻切迹的位置等特点,这一新种当为始巨犀属中比较进步的一个成员,是包氏始巨犀和巨犀之间的过渡类型的犀类动物。 相似文献
3.
A组轮状病毒SA11VP6基因的克隆和表达 总被引:4,自引:0,他引:4
从SA11VP6基因全序列克隆开始,设计一对两端带有酶切位点的引物,逆转录PCR扩增出VP6全基因CDNA。经酶切后插入PUC19,构建了VP6全基因克隆PRA6。再经酶切后插入痘苗病毒载休质凿PJSA1175中。利用Lipofectin导入TK143细胞,利用TK基因和Lac基因作为重组病毒的筛选标记。表达产物用单克隆抗体ELISA法检测,发现细胞培养上清和细胞裂解液都是阳性。Western b 相似文献
4.
为了探究三角帆蚌(Hyriopsis cumingii)糖原合成激酶-3β(GSK3β)基因对壳色的影响,研究采用RACE技术获得Hc-GSK3β基因cDNA全长1867 bp,其中包含1261 bp的ORF区编码420个氨基酸, ORF中含有一个S_TKc结构域,该结构域序列高度保守。组织差异表达分析发现Hc-GSK3β基因在紫色蚌鳃、斧足、内脏团和边缘膜组织中表达量高于白色蚌的表达量(P<0.05),且在斧足和边缘膜表达差异水平达到极显著(P<0.01),而在紫色蚌闭壳肌组织中表达量显著低于白色蚌(P<0.05)。原位杂交(ISH)实验结果显示在三角帆蚌外套膜的外褶、中褶、內褶、背膜区和腹膜区均有阳性信号产生,且在外褶的信号表达较强烈。该基因经重测序比较,共鉴定出6个SNP位点,其中在C+185A位点的CA基因型在紫色蚌的分布频率显著高于白色三角帆蚌(P<0.05);在紫色蚌中, T+341G位点TT基因型三角帆蚌内壳颜色参数b值显著低于TG基因型(P<0.05)。研究表明, Hc-GSK3β基因参与了三角帆蚌壳色形成,筛选的SNP标记可用于三角帆蚌壳... 相似文献
5.
《IRBM》2023,44(1):100728
Inner ear disorders' treatment remains challenging due to anatomical barriers. Robotic assistance seems to be a promising approach to enhance inner ear treatments and, more particularly, lead to effective targeted drug delivery into the human cochlea. In this paper we present a combination of a micro-macro system that was designed and realized in order to efficiently control the navigation of magnetic nanoparticles in an open-loop scheme throughout the cochlea, considering that the magnetic particles cannot be located in real time.In order to respect the anatomical constraints, we established the characteristics that the new platform must present then proceeded to the design of the latter. The developed system is composed of a magnetic actuator that aims to guide nanoparticles into the cochlea. Mounted on a robotic manipulator, it ensures its positioning around the patient's head. The magnetic device integrates four parallelepiped-rectangle permanent magnets. Their arrangement in space, position and orientation, allows the creation of an area of convergence of magnetic forces where nanoparticles can be pushed/pulled to. To ensure the reachability of the desired orientations and positions, a 3 DOF robot based on a Remote Centre of Motion (RCM) mechanism was developed. It features three concurrent rotational joints that generate a spherical workspace around the head. The control of the latter is based on kinematic models.A prototype of this platform was realized to validate the actuation process. Both magnetic actuator and robotic manipulator were realized using an additive manufacturing approach. We also designed a virtual human head with a life-size cochlea inside. A laser was mounted on the end effector to track the positioning of the actuator. This permitted to experimentally prove the capacity of the robotic system to reach the desired positions and orientations in accordance with the medical needs.This promising robotic approach, makes it possible to overcome anatomical barriers and steer magnetic nanoparticles to a targeted location in the inner ear and, more precisely, inside the cochlea. 相似文献
6.
《遗传学报》2023,50(2):63-76
The phenomenon of planar cell polarity is critically required for a myriad of morphogenetic processes in metazoan and is accurately controlled by several conserved modules. Six “core” proteins, including Frizzled, Flamingo (Celsr), Van Gogh (Vangl), Dishevelled, Prickle, and Diego (Ankrd6), are major components of the Wnt/planar cell polarity pathway. The Fat/Dchs protocadherins and the Scrib polarity complex also function to instruct cellular polarization. In vertebrates, all these pathways are essential for tissue and organ morphogenesis, such as neural tube closure, left–right symmetry breaking, heart and gut morphogenesis, lung and kidney branching, stereociliary bundle orientation, and proximal–distal limb elongation. Mutations in planar polarity genes are closely linked to various congenital diseases. Striking advances have been made in deciphering their contribution to the establishment of spatially oriented pattern in developing organs and the maintenance of tissue homeostasis. The challenge remains to clarify the complex interplay of different polarity pathways in organogenesis and the link of cell polarity to cell fate specification. Interdisciplinary approaches are also important to understand the roles of mechanical forces in coupling cellular polarization and differentiation. This review outlines current advances on planar polarity regulators in asymmetric organ formation, with the aim to identify questions that deserve further investigation. 相似文献
7.
本文记录了我国蒙新区土蝽科1新种:新疆光土蝽Sehirus xinjiangensis sp.nov。及4个中国新纪录种:黄圆土蝽Bysinus penicillatus E.Wagner,小圆土蝽B.minor E.Wagner,光头伊土蝽Aethus laeviceps Kerzher及斜光土蝽S.parens Mulsant et Rey。 相似文献
8.
我们用二相电泳方法在小鼠畸胎瘤系统中发现小鼠胚胎内细胞团标志蛋白双联体(分子量39,000,p14.4—4.5)也存在于未分化的胚胎癌细胞株(PSAI-NG2、F9、PCC3)中,但在已分化细胞株滋养层母细胞癌TDM1中用二相电泳方法不能检查到这蛋白。把EC细胞分为细胞质、细胞核、染色体三部分再进行检查,可以清楚地看到这蛋白主要存在于染色体部分。把染色体再分成0.35M NaCl可溶性,2M NaCl可溶性及2M NaCl不溶性三个组份时,则这蛋白出现在0.35M NaCl可溶性组分中,表明它是与染色体疏松结合的非组蛋白染色体蛋白。这蛋白是一种耐热性蛋白,在80℃受热10分钟不能使它变性。用制备型SDS聚丙烯酰胺凝胶电泳对经热处理的0.36M NaCl可溶性染色体蛋白进行分离,可得到电泳纯的小鼠内细胞团标志蛋白。由于这蛋白约占细胞总蛋白0.6%,与染色体疏松结合,又与早期胚胎细胞的多能性相关,提示它在维持多能细胞染色体构象方面有重要作用。 相似文献
9.
The dielectric dispersion of isolated intact mitochondria in suspension has been measured between 10 kHz and 500 MHz. In isotonic KCI media at 4°C, the mitochondria maintained their characteristic ‘double membrane’ structure as examined by electron microscopy, and the observed dispersion curves were successfully simulated in terms of a superposition of two sub-dispersions having different characteristic frequencies and different permittivity magnitudes. Taking these observations into account we analyzed the dispersion data on the basis of a ‘double-shell’ model in which two concentric shells are meant to represent the mitochondrial outer and inner membranes. The analyses by a computerized curve-fitting method revealed that: (i) electric capacities for the outer and the inner membrane are 1.7 and 0.5 μF/cm2, respectively, (ii) relative permittivity for the inner compartment (or the equivalent homogeneous matrical space) = 50–60, (iii) outer compartment-to-external conductivity ratio = 0.4–0.6, and (iv) inner compartment-to-external conductivity ratio = 0.14. The implications of these parameter values are discussed with due attention paid to the limitations inherent in our ‘double-shell’ model approach. 相似文献
10.
- 1. 1. The 31P-NMR characteristics of intact rat liver mitochondria, mitoplasts and isolated inner mitochondrial membranes, as well as mitochondrial phosphatidylethanolamine and phosphatidylcholine, have been examined.
- 2. 2. Rat liver mitochondrial phosphatidylethanolamine hydrated in excess aqueous buffer undergoes a bilayer-to-hexagonal (HII) polymorphic phase transition as the temperature is increased through 10°C, and thus prefers the HII) arrangement at 37°C. Rat liver mitochondrial phosphatidylcholine, on the other hand, adopts the bilayer phase at 37°C.
- 3. 3. Total inner mitochondrial membrane lipids, dispersed in an excess of aqueous buffer, exhibit 31P-NMR spectra consistent with a bilayer arrangement for the majority of the endogeneous phospholipids; the remainder exhibit spectra consistent with structure allowing isotropic motional averaging. Addition of Ca2+ results in hexagonal (HII) phase formation for a portion of the phospholipids, as well as formation of ‘lipidic particles’ as detected by freeze-fracture techniques.
- 4. 4. Preparations of inner mitochondrial membrane at 4 and 37°C exhibit 31P-NMR spectra consistent with a bilayer arrangement of the large majority of the endogenous phospholipids which are detected. Approx. 10% of the signal intensity has characteristics indicating isotropic motional averaging processes. Addition of Ca2+ results in an increase in the size of this component, which can become the dominant spectral feature.
- 5. 5. Intact mitochondria, at 4°C, exhibit 31P-NMR spectra arising from both phospholipid and small water-soluble molecules (ADP, Pi, etc.). The phospholipid spectrum is characteristic of a bilayer arrangement. At 37°C the phospholipids again give spectra consistent with a bilayer; however, the labile nature of these systems is reflected by increased isotropic motion at longer (at least 30 min) incubation times.
- 6. 6. It is suggested that the uncoupling action of high Ca2+ concentrations on intact mitochondria may be related to a Ca2+-induced disruption of the integrity of the inner mitochondrial phospholipid bilayer. Further, the possibility that non-bilayer lipid structures such as inverted micelles occur in the inner mitochondrial membrane cannot be excluded.
Keywords: 31P-NMR; Inner mitochondrial membrane; Phosphatidylethanolamine; Ca2+; Hexagonal (HII) phase; Lipidic particle 相似文献