ULTRASTRUCTURAL STUDIES OF SPERMATOGENESIS IN THE ANTHOCEROTALES. I. THE BLEPHAROPLAST AND ANTERIOR MITOCHONDRION IN PHAEOCEROS LAEVIS: EARLY DEVELOPMENT

Electron microscopic examination of thin sections showed that the blepharoplast of a young spermatid of Phaeoceros consists of two side-by-side centrioles and an accumulation of osmiophilic, granular matrix at their proximal ends. Lying between these nearly parallel organelles is a dark-staining body that will later disappear at the onset of flagellogenesis. For a brief period the centrioles are oriented perpendicular to the nuclear surface so that the granular matrix at their proximal ends is confluent with the nuclear envelope; furthermore, the nucleoplasm immediately in front of the centrioles becomes densely staining. The multilayered structure (MLS) develops directly under the centrioles. It comprises a band of 12 microtubules (the S₁ stratum) and three lower strata (S_2–4) whose constitutent lamellae are oriented at an oblique angle to the S₁ axis. While the S₁ tubules grow rearward over the nucleus which forms a beak adjacent to the posterior end of the lamellar strata, the centrioles are transformed into basal bodies with the distal growth of the axonemes and the proximal growth of the central cartwheels and lowermost triplets. The proximal ends of the basal bodies and the S₁ tubules overlying the lamellar strata are invested with osmiophilic matrix that extends down to the S₂ layer and may temporarily occlude the lamellar plates. At the onset of nuclear elongation an anterior mitochondrion becomes situated close beneath the lamellar strata which extend laterally beyond the S₁ tubules.     

COMPARATIVE ULTRASTRUCTURAL STUDIES OF SPERMATOGENESIS IN THE METZGERIALES (HEPATOPHYTA) II. THE BLEPHAROPLAST OF BLASIA PUSILLA

As in other hepatics, the young spermatid of Blasia pusilla contains a well-developed blepharoplast comprising a four-layered multilayered structure (MLS) and two overlying dimorphic basal bodies. The asymmetrical spline (S₁ or upper stratum of the MLS) numbers 20 or 21 microtubules (MTs) at its anterior tip and reduces to eight at the posterior limit of the lamellar strip (LS). Behind this the shank of the spline is five or six tubules in width over most of its length, approximately one revolution of the circumference of the gamete. The three-microtubule spline aperture underlies the anterior basal body and like those of most hepatics, it is closed at its anterior end. The asymmetrical LS (approx. 2.0 μm in length) is characterized by a right-hand posterior notch which lies below the spline aperture at the region of the cartwheel configuration of the anterior basal body (ABB). The staggered dimorphic basal bodies overlap for approximately one third of their lengths. Both lie parallel to the long axis of the spline. As in other hepatics, the ABB (1.2 μm in length) is subapical and comprises an anterior hub extension with progressive rearward additions of lateral, dorsal and ventral triplets. Over most of its length (2.1 μm) the longer posterior basal body (PBB) consists of a distinct central hub and three ventral triplets. Transition zones of both basal bodies contain stellate configurations into which the two central axonemal MTs frequently extend. The blepharoplast of Blasia shows several features in common with leafy, simple thalloid and complex thalloid liverworts. Compared with the few Metzgeriales observed thus far, the LS is less elongate and the basal bodies less staggered. Dimensions of basal body components and spline dimensions, however, are comparable to those of most leafy and thalloid hepatics. Striking similarities with the complex thalloid liverworts include a posterior notch in the LS and a spline aperture three MTs wide.     

STUDIES OF SPERMATOGENESIS IN THE HEPATICAE V. BLEPHAROPLAST DEVELOPMENT IN MARCHANTIA POLYMORPHA

Coaxial centrioles and a microtubule organizing center (MTOC) constitute each centrosome in spermatid mother cells of Marchantia polymorpha. During cell division the centrosome separates at its midregion and the two centrioles undergo a planar rotation that brings them to lie somewhat staggered and nearly parallel with their proximal ends embedded in osmiophilic granular material similar in appearance to that of the MTOC. Microtubules of the multilayered structure (MLS) arise in this material below the posterior centriole and parallel to its long axis. The rotation of centrioles and the initiation of S₁ tubules below the posterior centriole determine polarity of the incipient blepharoplast. Lower MLS strata are formed under the anterior centriole by the compaction of granular, osmiophilic matrix. Formation and growth of S₂ vertical lamellae occur at the left front edge of the MLS in association with MTOC-like matrix localized near the cell membrane. The MLS enlarges to about 0.4 μm wide by 0.6 μm long and is ovoid in outline except for a short distal projection underlying the posterior centriole. Subsequently the lamellae are transformed into homogenous, osmiophilic matrix that contributes directly to the expansion of all MLS strata including microtubules. The stratum of lamellae is interpreted as a planar MTOC subject to morphogenetic control. Each of the four strata grows proximally while the tapering distal projection lengthens beneath the posterior basal body. Dense matrix above the MLS, apparently elaborated by the S₂ layer, is organized into cartwheel and triplet components of the basal bodies’ proximal extensions. Organization of triplet tubules proceeds from proximal to distal toward preexisting triplets. Osmiophilic matrix contributes to the formation of microtubule keels and osmiophilic crests and may serve as a cementing material that stabilizes the spatial relationships of blepharoplast components. After full expansion of the MLS’ lower strata, the S₂ layer is reorganized into lamellae. Flagellar growth in Marchantia is postulated to involve a process whereby subunits or their precursors are elaborated by the MLS, translocated to the distal end of the flagellum and incorporated into the axonemal tubules. When MLS microtubules elongate to form a long, narrow band, the distal half of the S₂ layer is again in the osmiophilic matrix state.     

COMPARATIVE ULTRASTRUCTURAL STUDIES OF SPERMATOGENESIS IN THE METZGERIALES (HEPATICAE). I. THE BLEPHAROPLAST OF PALLAVICINIA LYELLII

The blepharoplast in the young spermatid of Pallavicinia is similar to that of other hepatics in that it comprises a four-layered multilayered structure (MLS) and two staggered, dimorphic basal bodies. The spline, approximately 40 μm in length and extending through nearly two full gyres, comprises 20 parallel microtubules at its anterior end and narrows to 17 at the posterior limit of the subjacent lamellar strip (LS). Behind this, the spline shank, approximately 32 μm in length, is reduced to six tubules. The LS curves around the spermatid, following the anterior one-third of the first gyre of the spine, and is approximately 7.5 μm in length, the longest yet recorded for the bryophytes. It is spatulate in outline, equaling the width of the spline anteriorly but tapering steeply from the right-hand side behind the anterior basal body (ABB). It then extends posteriorly as a narrow strip beneath the left-hand margin of the spline. The basal bodies of the greatly staggered flagella are nonoverlapping and separated by a distance of about 4.4 μm. The subapical ABB and PBB measure (including the ventral triplet extensions and transition zones) 1.2 μm and 2.4 μm in length, respectively. A short, narrow aperture equaling one tubule-diameter in width is located in the spline directly beneath the ABB. The anterior mitochondrion is about 7 μm long and follows the outline of the overlying LS, while a cupshaped posterior mitochondrion is appressed to the plastid. Comparisons with other taxa indicate that major distinguishing features of metzgerialian blepharoplasts are highly staggered, nonoverlapping basal bodies, greatly elongate anterior mitochondria, and six-tubule shanks. Great differences between the spermatids suggest wide phylogenetic discontinuities between the genera of the Metzgeriales.     

STUDIES OF SPERMATOGENESIS IN THE HEPATICAE. IV. ON THE BLEPHAROPLAST OF BLASIA

Spermatogenesis in Blasia pusilla L. was reexamined with electron optics to help evaluate conflicting results of the two earlier light microscope studies of this species. The present micrographic resumé of spermatid transformation confirms Sharp's observation of centrosomes in very young spermatids and agrees with Woodburn's general account of spermatozoid maturation. Further, male gamete development in Blasia is shown to be closely comparable to that of Marchantia and Pellia. It is concluded that Sharp's report of blepharoplast development in Blasia by fragmentation and coalescence was based on anomalous plant material.     

SPERMATOGENESIS IN COLEOCHAETE PULVINATA (CHAROPHYCEAE): EARLY BLEPHAROPLAST DEVELOPMENT

Transmission electron microscopy of serial thin sections was used to reconstruct several early developmental stages of the blepharoplast in Coleochaete pulvinata spermatids. These were compared to published studies of blepharoplast development in Charales and the closest relatives of charophycean green algae among embryophytes, i.e., hornworts and liverworts. Bicentriolar centrosomes such as occur in bryophytes and fern allies were not observed in Coleochaete. Centriole replication in C. pulvinata was orthogonal as in Charales. The resulting two daughter centrioles were oriented perpendicularly and joined proximally by electron-dense material. Their orthogonal relationship was maintained throughout blepharoplast development by a massive, banded connective which appeared early. In spermatids of hornworts and liverworts, a multilayered structure (MLS) develops in association with two centrioles destined to become flagellar basal bodies. When the MLS of these lower land plants is sectioned at right angles to the long axis of the microtubular layer, the MLS is observed to lie beneath cross sections of both centrioles. In contrast, when developing MLSs of C. pulvinata and Charales are similarly sectioned, they occur beside a cross section of just one of the two centrioles. In C. pulvinata (as in other charophytes), MLS lamellae are oriented at a 90-degree angle to the long axis of the S₁ microtubules from the beginning. This contrasts with the 40–45 degree angle between the MLS lamellae and S₁ microtubules universally reported for archegoniates. In early C. pulvinata spermatids, spline microtubules are closely associated with an anterior mitochondrion having a low stromal density and few cristae. An anterior mitochondrion is typically associated with blepharoplast development in hornworts and liverworts, but has not previously been reported to occur in Coleochaete or any other charophycean alga. In Coleochaete, as in hornworts and liverworts, but unlike Charales, structure of mature blepharoplasts reflects early blepharoplast ontogeny. Very little change in positional relationships among blepharoplast components (flagella, connective, MLS) occurs during development. These character-state differences are of importance in cladistic analyses of charophycean algae and lower land plants.     

扬子鳄胚胎发育后期端脑背侧区的超微结构观察

背侧区位于大脑半球的外侧沟和终沟之间,向脑腔突入,几乎占满整个脑腔,有视觉,听觉和躯体感觉等重要功能,一些作者称它为脑室背嵴(Dorsal ventricular ridge).爬行类成体端脑背侧区的形态学和超微结构研究在国外有所报道1-3,而其胚胎发育详细资料只见于1987年Yanes对蜥蜴背侧区的研究4.扬子鳄(Alligator sinensis Fauvel)为国家重点保护动物之一,研究其组织胚胎结构在系统进化和饲养方面有着重要意义,同时也可填补国内在爬行类脑研究上的空白.       

草鱼肾脏,脾脏血细胞发育过程超微结构与细胞化学的研究

本文报告了草鱼肾脏、脾脏血细胞各系统发育各阶段细胞超微结构与某些细胞内的化学成分如糖原、脂类、酸性磷酸酶、酸性非特异性酯酶、碱性磷酸酶、过氧化物酶（ＰＡＳ、ＳＢ、ＡｃＰ、ＡＮＡＥ、ＡＩＰ、Ｐｏｘ）的变化规律。讨论了草鱼造血的特点、方式以及超微结构、细胞内化学成分变化与携氧、免疫功能的关系和意义。草鱼肾脏、脾脏造血基质细胞主要包括三大类：纤维细胞可分为功能活跃的成纤维细胞及不活跃的纤维细胞;网状细胞和毛细血管内皮细胞可分为非吞噬性及吞噬性两型的。初步探讨了造血基质细胞与造血微环境的作用。     

ULTRASTRUCTURAL STUDIES ON SPHAEROPLEA ANNULINA (CHLOROPHYCEAE). II. SPERMATOGENESIS AND MALE GAMETE STRUCTURE1,2

The development and ultrastructure of the male gamete of Sphaeroplea annulina (Roth) Agardh have been investigated. Multiple mitoses each associated with phycoplast microtubules occur as a result of nitrogen deficiency in the culture medium. A regular cleavage of the cytoplasm delineated by microtubules then occurs, resulting in many young male gametes. During maturation the gametes are retained within a vacuolar envelope. Maturation entails reduction in nuclear size and chromatin condensation, loss of chloroplast thylakoids, endoplasmic reticulum and Golgi apparatus. The apical region where the two flagella are inserted consists of an apical cone and fibrous connections which lie distal to the basal bodies. The study supports the suggestion put forward in a previous paper: namely that the genus Sphaeroplea be retained in a separate order the Sphaeropleales.     

STUDIES OF SPERMATOGENESIS IN THE HEPATICAE : II. Blepharoplast Structure in the Spermatid of Marchantia

The blepharoplast in a young, developing spermatid of Marchantia polymorpha, is a composite structure consisting of two basal bodies and a subjacent narrow band of axonemal-type tubules that we have termed the "spline." For most of its length, the spline consists of six long parallel tubules that nearly encircle the cell. The spline anterior is asymmetrically widened for about 2 µ by shorter tubules of the same kind. The lateral displacement of three long, adjacent marginal tubules by three short intervening tubules at the spline tip produces a long narrow aperture. Distally, the aperture is closed by the convergence of the displaced tubules with another trio of long tubules. Together, these form the six-membered cell-encircling portion. The expanded spline anterior has, at this stage of development, the four-layered (Vierergruppe) structure, of which the aforementioned tubules constitute the uppermost layer. The lower three strata consist of diagonal fins, elongated chambers, and fine tubules, respectively. The two flagellar bases lie close above the spline tip—one slightly anterior to the other—and diverge unequally from the spline axis. A few triplets extend proximally from the basal bodies, but do not connect with the spline. The anterior basal body is longer than the posterior one.     

鲤科鱼类前方椎体的形成及其在系统发育上的意义

本文对九种鲤科鱼类与中国胭脂鱼幼体的前方椎体的发育进行了比较。观察结果表明这两个科鱼类的前方椎体发育是近似的,它们的魏氏小骨有共同的来源;魏氏复合骨由前方椎体上方的第二骨化中心形成,这个骨化中心与第三和第四上神经骨相当。另一方面,胭脂鱼幼体的第二椎体副突已与第四椎体的胸肋相接;魏氏复合骨的扩展是骨化中心背脊部均匀地发生的,这些与鲤科有着明显的不同。鲤科幼体的魏氏复合骨发育具有共同的特点,第二骨化中心的前方有一棘状物在早期出现,它代表了第三上神经骨伸出部份。但随后的发育可以区分为两种不同方式:一种为雅罗系鱼类所具有,即第二骨化中心以棘状物的扩展为主,前、后棘存在并有缝合线相连;另一种为鲃系鱼类所有,即第二骨化中心的发育以其背中部伸出的实心嵴突为主,仅有不发达的前棘,此系属于派生性结构。与魏氏复合骨相关的是2—3椎体间的关系也有相应的差别:雅罗系鱼类的幼体其2—3椎体间分离(仅鳑(鱼皮)亚科鱼类例外),而鲃系鱼类的幼体其2—3椎体愈合。由于幼体魏氏复合骨与椎体的特征比成体表现更为明显,它们在系统发育上能提供更为清楚的信息。     

鲶鱼小窝器官的后期发育及形态的研究

电感官包括结节器官(tuberous organ)和壶形器官(ampullary organ)二大类。前者仅存在于电鱼上,后者则在电鱼及某些非电鱼都有发现。对于淡水鲶鱼而言,其壶形器官又称为小窝器官(small pit organ)。行为实验表明某些鱼类的小窝器官有极高的电敏感性,能检测0.5—0.8 nA/cm~2的电流刺激(Peters,1974;Kalmijn,1976),同时有不少报告描述了它的显微和亚显微结构(Sato,1949,1956,1969;Wachtel,1969;Roth,1969)。但是对这种器官的发育过程的研究报告还不多。     

中华双腔吸虫精子发生的超微结构研究

应用透射电镜技术,研究中华双腔吸虫的精子发生,并与其它复殖吸虫进行比较,提出了复殖吸虫精子发生的一般过程,结果显示它与大多数复殖吸虫精子发生的超微结构相似,原始的精原细胞经过次有丝分裂,两次减数分裂成为精细胞,它经过分化,形态变化后成为成熟精子,精子形成共分为六个阶段。其中形成共分为六个阶段,其中有以下首次报道的特征,（１）中央胞持区的生长速度在开始时比鞭毛裂快;（２）在鞭毛与中央胞质区融合前,线     

ULTRASTRUCTURAL STUDIES ON STOMATA DEVELOPMENT IN INTERNODES OF AVENA SATIVA

A study of stornata development in internodes fixed with glutaraldehyde and osmium tetroxide revealed the following features: (1) young subsidiary and guard cells have proplastids, but in the mature stomatal apparatus only guard cells have starch-containing plastids; (2) cytoplasmic continuities found in the developing stomatal apparatus included (a) plasmodesmata between young guard and subsidiary cells and (b) pores at each end of the guard cells in the wall common to these two cells (the pores are found in immature as well as mature stornata); (3) a locus of microtubules was found just inside the plasmalemma of the wall common to the two guard cells. These microtubules are generally parallel to the radial axis of this wall. They are concentrated at the site where localized wall thickening and aperture formation occur. After wall thickening begins around the developing aperture, microtubules are found running primarily in a plane perpendicular to the wall thickening. The possible functional significance of these microtubules and the cytoplasmic continuities in the stomatal apparatus is discussed.     

台湾东风螺精子发生和精子形态的超微结构研究

透射电镜研究结果表明,台湾东风螺(Babylonia formosae~**)精子形成过程中经历了一系列重大的形态变化,主要有核逐步拉长、染色质浓缩、顶体形成、线粒体逐渐发达与融合以及中心粒演变为轴丝等过程。其中精细胞分化可分为6个时期。成熟精子的外形呈发丝状,由头部和尾鞭两大部分组成,头部包括顶体复合体和核,尾鞭可分为中段、主段和末段。精子的形态及功能与软体动物的系统发育有密切关系。本文还就台湾东风螺精子形成过程和形态与其它前鳃类作了比较。     

THE USE OF MILLIPORE FILTERS IN ULTRASTRUCTURAL STUDIES OF CELL CULTURES AND VIRUSES

A technique is described for embedding tissue culture cells that have been adsorbed or grown on Millipore filters. The acetone used during the embedding process rendered the filters transparent so that specific areas or cells could be chosen with the aid of the light microscope. Lymphoblastoid cells processed on the filters possessed well-defined plasma membranes and microvilli which were rarely present in cells from parallel cultures that were prepared by pelleting in the centrifuge. Fibroblast cells grown on filters retained their elongated appearance, in contrast to the rounded cells in pelleted preparations. Millipore filters were also used as a means of embedding virus pellets for sectioning. Preparations containing as few as 4 x 10⁸ virus particles were suitable for study by the filter technique. Crude tissue-culture harvests of vaccinia virus and purified preparations of Rauscher murine leukemia and adeno-satellite viruses were successfully examined.     

中国圆田螺典型精子及其发生的超微结构研究

运用光镜和电镜以及细胞化学方法 ,对中国圆田螺Cipangopaludinachinensis典型精子及其发生的超微结构进行了研究。根据染色质和细胞形态的变化 ,可将其典型精子发生分为五个时期 :精原细胞、初级精母细胞、次级精母细胞、精细胞和成熟精子。精子发生过程中 ,线粒体逐渐增大 ,并随着轴的增生而不断发展为螺旋化线粒体系 ;染色质逐渐凝聚 ,经过颗粒化和纤维化而终呈均质 ;随着染色质的变化 ,细胞核先变小再拉长并螺旋化。精细胞期细胞核基部发生内陷 ,伴随有中心粒的移入 ,并向后方形成“9 2”式的轴。成熟典型精子单鞭毛 ,全长约 40 μm ,包括头、中、尾三段 :头段螺旋状 ,主要由细胞核构成 ,旋束单股 ;中段螺旋状 ,主要由线粒体和轴丝构成 ,旋束四股 ;尾段非螺旋状 ,主要由糖原颗粒和轴丝构成     

LIGHT AND ELECTRON MICROSCOPE STUDIES OF MORPHOLOGICAL CHANGES OF MITOCHONDRIA DURING SPERMATOGENESIS IN THE GRASSHOPPER

1. Observations on the morphological changes of mitochondria preparatory to the formation of the nebenkern, as well as changes within the nebenkern, are reported. 2. Mitochondria enlarge and divide during the meiotic divisions. 3. The mitochondria of the spermatid elongate, become filamentous, form a crescent, and partially encircle the nucleus. 4. Nodes which develop on either end of the crescent become entwined as they move toward each other. 5. The two nodes coalesce to form a filamentous or early type nebenkern which is described by others as chromophilic. 6. Internal rearrangement and partial dissolution of the filaments result in the development of the late or chromophobic nebenkern which separates into two distinct bodies. 7. The nebenkern moieties send out processes toward the centrosome, and after making contact, elongate and occupy part of the space between the tail filaments and sheath of the spermatozoon.