Golgi apparatus cisternae of monensin-treated cells accumulate in the cytoplasm of liver slices

Protein transport via the endoplasmic reticulum Golgi apparatus-cell surface export route was blocked when slices (6-15 cells thick) of livers of 10-day-old rats were incubated with 1 microM monensin. Production of secretory vesicles by Golgi apparatus was reduced or eliminated and, in their place, swollen cisternae accumulated in the cytoplasm at the trans Golgi apparatus face. The swelling response was restricted to the six external cell layers of the liver slices, and the number of cells showing the response was little increased by either a greater concentration of monensin or by longer times of incubation. When monensin was added post-chase to the slices, flux of radioactive proteins to the cell surface was inhibited by about 80% as determined from standard pulse-chase analyses with isolated cell fractions. Radioactive proteins accumulated in both endoplasmic reticulum and Golgi apparatus and in a fraction that may contain monensin-blocked Golgi apparatus cisternae released from the stack. The latter fraction was characterized by galactosyltransferase/thiamine pyrophosphatase ratios similar to those of Golgi apparatus from control slices. The use of monensin with the tissue slice system may provide an opportunity for the cells to accumulate monensin-blocked Golgi apparatus cisternae in sufficient quantities to permit their isolation and purification by conventional cell fractionation methods.     

Cleavage furrow establishment by the moving mitotic apparatus

The midpoint of the mitotic apparatus is fixed in the future division plane long before the division mechanism develops, and this static relationship has been considered essential in speculations concerning division mechanism establishment. The purpose of the present investigation was to determine whether prevention of the static relationship affects the establishment process. Sand dollar eggs were reshaped into cylinders by confinement in an elastic capillary tube and, beginning about 20 min before cleavage, the mitotic apparatus was kept in reciprocal motion by alternately compressing the poles. When the movement was continuous and the excursions were 25, 50 or 75 μm, furrow activity developed near the midpoint of the region underlain by the mitotic apparatus. The acuteness of the furrow decreased as the distance the mitotic apparatus was moved increased. When the movement was made discontinuous by allowing the mitotic apparatus to pause at the end of each excursion, the results depended upon the duration of the pause. Pauses 30 s long resulted in a single furrow formed in the midpoint of the entire region underlain by the mitotic apparatus. When the pauses were 45s long, furrowing activity developed in both regions where the mitotic apparatus was allowed to pause. The results indicated that the normal static relation between the mitotic apparatus midpoint and the division plane is unnecessary for division mechanism establishment. They also demonstrate that a restricted region of contractile activity can be established in the cortex despite experimentally induced spreading and dilution of mitotic apparatus effect.     

LYSOSOMAL PACKAGING IN DIFFERENTIATING AND DEGENERATING ANURAN LATERAL MOTOR COLUMN NEURONS

The role of the Golgi apparatus and the Golgi-endoplasmic reticulum-lysosome complex (GERL) in the genesis of lysosomes was examined in differentiating and degenerating motor neurons of anuran larvae. Acid phosphatase, aryl sulfatase, and thiolacetic acid esterase were utilized as marker enzymes for the lysosomal system, while nucleoside diphosphatase and thiamine pyrophosphatase labeled the inner saccule(s) of the Golgi apparatus. Reduced osmium tetroxide was routinely deposited in the outer Golgi saccule regardless of the state of neuronal maturation. In all young neurons, the disposition of acid hydrolase reaction product paralleled the formation of GERL, with no lytic activity in the Golgi apparatus per se. Hypertrophy of the Golgi apparatus and GERL was observed in the early phases of degeneration, and both organelles apparently exhibit extensive hydrolytic activity. Dense bodies, autophagic vacuoles, and primary lysosomes were found arising from GERL, while the Golgi apparatus may produce primary lysosomal granules during regression. On the other hand, in differentiating neurons, hydrolytic activity was restricted to GERL and an occasional dense body and autophagic vacuole. These studies illustrate a parallelism between the development of GERL and genesis of primary and secondary lysosomes during neuronal cytodifferentiation, and implicate GERL and possibly the Golgi apparatus in lysosomal packaging in degenerating neurons.     

Studies on the Mitotic Apparatus of the Sea Urchin by Means of Antigen-Antibody Reactions in Agar

The primary purpose of the experiments reported in this paper was to gain information on the molecular origin of the mitotic apparatus. Antisera were prepared against unfertilized sea urchin (Strongylocentrotus purpuratus) egg antigens and mitotic apparatus antigens. These were permitted to react with various antigen solutions in Ouchterlony agar gel diffusion plates, and the resultant precipitation patterns analysed. The results revealed that the mitotic apparatus contains probably no more than two antigens (precursor-1 component and precursor-2 component) and that these are shared by the unfertilized egg. Absorption and fractionation techniques indicated that in the unfertilized egg the precursor-1 component is present both as a "soluble" protein and as an insoluble form tenaciously associated with intracellular structural elements. A survey of dividing and non-dividing tissues for the precursor-1 component revealed that it was restricted to tissues in which mitotic activity could be detected microscopically. No immunochemical relationship could be detected between the mitotic apparatus and proteins extracted, by various methods, from the lantern muscle.     

Sexual dimorphism of the Weberian apparatus and pectoral girdle in Sundadanio axelrodi (Ostariophysi: Cyprinidae)

The miniature cyprinid fish, Sundadanio axelrodi , exhibits extreme sexual dimorphism in the skeleton of the Weberian apparatus, the fifth rib and pectoral girdle. Musculature associated with the fifth rib and Weberian apparatus also shows a high degree of sexual dimorphism. It is suggested that these modifications are responsible for the production of a croaking sound that seems to be restricted to males of the species, based on the lack of any corresponding anatomical specializations in females.     

Demonstration of an extensive trans-tubular network continuous with the Golgi apparatus stack that may function in glycosylation

Sialyltransferase (Galβ1,4GlcNAc α2,6 sialyltransferase) was localized by immunoelectron microscopy in rat liver hepatocytes using affinity-purified antibodies. Immunoreactivity for sialyltransferase was found in the Golgi apparatus, where it was restricted to an interconnected system consisting of the trans-cisternae and the trans-tubular network. This region of the Golgi apparatus exhibited both TPPase and CMPase activity and was the intracellular site where sialic acid residues bound to glycoprotein were detected using the Limax flavus lectin. Sialyltransferase and sialic acid residues were not detected in medial and cis-cisternae of the Golgi apparatus. These findings suggest that in rat hepatocytes sialylation of N-linked glycoproteins occurs in the complex formed by the trans-cisternae and the trans-tubular network of Golgi apparatus.     

Isolation of a Golgi apparatus-rich fraction from rat liver. IV. Thiamine pyrophosphatase

The thiamine pyrophosphatase (the enzyme [s] catalyzing the release of inorganic phosphate with thiamine pyrophosphate as the substrate) activities of Golgi apparatus-, plasma membrane-, endoplasmic reticulum-, and mitochondria-rich fractions from rat liver were compared at pH 8. Activity was concentrated in the Golgi apparatus fractions, which, on a protein basis, had a specific activity six to eight times that of the total homogenates or purified endoplasmic reticulum fractions. However, only 1–3% of the total activity was recovered in the Golgi apparatus fractions under conditions where 30–50% of the UDPgalactose:N-acetylglucosamine-galactosyl transferase activity was recovered. Considering both recovery of galactosyl transferase and fraction purity, we estimate that approximately 10% of the total thiamine pyrophosphatase activity of the liver was localized within the Golgi apparatus, with a specific activity of about ten times that of the total homogenate. Cytochemically, reaction product was found in the cisternae of the endoplasmic reticulum as well as in the Golgi apparatus. This is in contrast to results obtained in most other tissues, where reaction product was restricted to the Golgi apparatus. Thus, enzymes of rat liver catalyzing the hydrolysis of thiamine pyrophosphate, although concentrated in the Golgi apparatus, are widely distributed among other cell components in this tissue.     

Observations on the origins of plasma membrane in rat deciduoma

Summary An NADH-ferricyanide reductase activity resistant to inactivation by cytochemical procedures was examined during decidualization of rat endometrium. Resistant activity was restricted to plasma membranes, distal elements of the Golgi apparatus, and discoid cisternae and cytoplasmic vesicles of decidual cells of endometrium of the pseudopregnant rat on days 3, 4, 5, 7, and 9, after mating. The procedure reduced or eliminated any evidence of NADH-ferricyanide reductase activity from other cellular components such as endoplasmic reticulum, nuclei, and mitochondria. The observations of the glutaraldehyde-resistant reductase in both plasma membranes and discoid cisternae may indicate a role for the latter in the biosynthesis of plasma membranes during decidualization when massive cell proliferation and membrane biosynthesis occur. The origin of the discoid cisternae is tentatively ascribed to the mature faces of the Golgi apparatus.Work supported in part by a grant from the NIH CA1880101 to D.J.M.     

Post-Golgi apparatus localization and regional expression of rat intestinal sialyltransferase detected by immunoelectron microscopy with polypeptide epitope-purified antibody

During studies on the Golgi apparatus immunolocalization of beta-galactoside alpha 2,6-sialyltransferase in intestinal cells, immunostaining of a number of post-Golgi apparatus structures including mucus droplets and plasma membrane were observed. In order to determine if this labeling was in fact due to sialyltransferase and not carbohydrate-specific antibodies in the polyclonal antiserum preparation, fusion protein to sialyltransferase was used to epitope purify polypeptide-specific antibodies. The affinity purification was performed on a column containing a beta-galactosidase-sialyltransferase fusion protein expressed in Escherichia coli. Using such antibodies we present evidence that in intestinal cells sialyltransferase is not only present in the Golgi apparatus cisternal stack but also its transtubular network and various post-Golgi apparatus structures. In absorptive enterocytes, post-Golgi apparatus vesicles, the brush border and basolateral plasma membrane, multivesicular bodies, and lysosome-like structures were labeled. In goblet cells the limiting membrane and lumen of forming and mature mucus droplets as well as the plasma membrane exhibited label for sialyltransferase. The results provide evidence for "ecto-sialyltransferase" in the plasma membranes of these cells, and suggest that most of the sialyltransferase is released from the Golgi membranes and becomes secreted with the goblet cell mucus. In addition, the polypeptide epitope-purified antibody was also used to examine regional expression of sialyltransferase in the rat intestinal epithelium. Immunolabel was restricted to the large intestine and not found in duodenum, jejunum, and ileum. Direct measurement of the enzyme activity was found to correlate with the immunoelectron microscopic data. This observation suggests that there is regional specific expression of the beta-galactoside alpha 2,6-sialyltransferase.     

Distribution of adenylate cyclase among membrane fractions of rat liver.

Adenylate cyclase activity was detected in plasma membranes, Golgi apparatus, and endoplasmic reticulum from rat liver. Adenylate cyclase activities of purified membranes were determined biochemically by two methods. In one, the synthesis of radioactive cyclic AMP from ATalpha32P was monitored. In the other, the synthesis of cyclic AMP was quantitiated using a protein which specifically binds cyclic AMP. The enzyme activity was responsive to activation by both glucagon and sodium fluoride although differences in degree of activation were noted comparing plasma membrane, Golgi apparatus, and endoplasmic reticulum. Cytochemical studies, using both whole tissue and purified cell fractions and conducted in parallel, confirmed the biochemical results. Deposition of lead phosphate, enhanced by glucagon and NaF with samples incubated with appropriate substrates, was not restricted to plasma membranes of hepatocytes but was present in intracellular membranes as well. Adenylate cyclase of rat hepatocytes appears more widely distributed among internal membranes than previously recognized.     

Immunohistochemical localization of type IV collagen fibronectin and laminin in the juxtaglomerular apparatus of the rat kidney

The juxtaglomerular apparatus (JGA) is a complex structure containing several components: the vessels, the extraglomerular mesangium and the distal tubule. These structures include cellular elements and an extracellular matrix (ECM). Collagenous (type IV collagen) and noncollagenous components of the basement membranes were studied. The localization of type IV collagen and of two extracellular glycoproteins (laminin and fibronectin) was investigated using immunofluorescent and immunoperoxidase labelled antibodies. Type IV collagen and laminin have the same localization on the JGA basement membranes. On the other hand, fibronectin is limited to the entrance of the glomerular stalk. On electron microscopy, type IV collagen is found in the basement membrane while fibronectin is restricted to certain areas of the extracellular matrix. These findings confirm data concerning the distribution of these three components in basement membranes and allow a better understanding of the histoarchitecture of the juxtaglomerular apparatus.     

The localization of thiamine pyrophosphatase activity in Meckel's cartilage cells during endochondral ossification

The cytochemical distribution of thiamine pyrophosphatase (TPPase) activity in Meckel's cartilage cells of the mouse embryo has been studied during the endochondral ossification. All the cartilage cells contain reaction product within the Golgi apparatus. In immature chondrocytes, at the reserve cell zone, TPPase activity is restricted to several inner cisternae of independent Golgi apparatus. In mature cells at the proliferative cell zone, several Golgi complexes form a Golgi network connecting with each other by the TPPase positive tubular stalks. Golgi cisternae, condensing vacuoles and vesicles also contain reaction product. In the hypertrophic chondrocytes located in the calcifying zone, their disorganized Golgi apparatus still retain reaction product. Some chondrocytes, even those located within calcified or opened lacunae, exhibit intact structures and normal cytochemical enzyme distribution. These data indicate the possibility that some chondrocytes may survive and contribute the formation of mandible.     

The localization of thiamine pyrophosphatase activity in Meckel's cartilage cells during endochondral ossification

Summary The cytochemical distribution of thiamine pyrophosphatase (TPPase) activity in Meckel's cartilage cells of the mouse embryo has been studied during the endochondral ossification. All the cartilage cells contain reaction product within the Golgi apparatus. In immature chondrocytes, at the reserve cell zone, TPPase activity is restricted to several inner cisternae of independent Golgi apparatus. In mature cells at the proliferative cell zone, several Golgi complexes form a Golgi network connecting with each other by the TPPase positive tubular stalks. Golgi cisternae, condensing vacuoles and vesicles also contain reaction product. In the hypertrophic chondrocytes located in the calcifying zone, their disorganized Golgi apparatus still retain reaction product. Some chondrocytes, even those located within calcified or opened lacunae, exhibit intact structures and normal cytochemical enzyme distribution. These data indicate the possibility that some chondrocytes may survive and contribute the formation of mandible.     

Fasciola hepatica: a technique for monitoring in vitro motility

An apparatus utilizing a force and displacement transducer is described for the direct and long-term recording of the motility in vitro of Fasciola hepatica. Normal movement is typically rhythmical, with bursts of more powerful contractions alternating with periods of lesser activity. Such rhythms and the overall level of activity are maintained for more than 30 hr. The fluke remains active for much longer periods of time: recordings of fluke movements have been made for up to 4 days. Potential damage to the fluke caused by the attachment system within the recording apparatus has been determined by the Evans' Blue Technique and scanning electron microscopy. It is restricted to the attachment sites, and does not spread to other parts of the body over the 30-hr normal activity period. Transmission electron microscope studies have shown that the tegument retains its structural and functional integrity over this period of time. There are advantages of the recording apparatus over previous kymographic methods for studying fluke motility.     

Selective expression of glionexin,a glial glycoprotein,in insect mechanoreceptors

The distribution of a glial cell-associated glycoprotein, glionexin (GX), on sensory receptors of the adult cricket Acheta domesticus is described, using the monoclonal antibody 5B12 as an immunohistochemical probe. GX was previously shown to be widely distributed in the embryo and to persist in the postembryonic to adult central nervous system. Here we demonstrate that it is restricted in the adult periphery to three subclasses of mechano-receptor sensilla: large socketed hair mechanoreceptors, their associated campaniform sensilla, and chordotonal organs. GX was not detected in photoreceptors, chemoreceptors, or other mechanoreceptors. The pattern of distribution differs significantly within the three subclasses of mechanoreceptors. In the hair and campaniform receptors GX is restricted to the extracellular space among glial cells clustered around the axon hillock region, but in chordotonal organs it surrounds the scolopidium at the tip of dendrites. The highly restricted distribution of GX in the periphery suggests possible functions that include mechanical stability of the sensory apparatus and ionic homeostasis in the respective neuronal spike-generating regions. The developmental modulation of GX expression is taken to imply multiple functions for the molecule during the life of the insect. 1994 John Wiley & Sons, Inc.     

假瘤蕨属 (水龙骨科) 植物叶表皮特征的比较研究

在光镜和扫描电镜下观察了假瘤蕨属2系、5亚系的24种植物的叶表皮。结果表明,叶表皮细胞形状不规则,垂周壁波曲状。下生气孔,气孔类型有极细胞型、共环极细胞型、腋下细胞型、聚腋下细胞型和不规则型,常伴生出现。在扫描电镜下,叶表皮气孔器外拱盖内缘为浅波状、少平滑;一些种的保卫细胞两端有“T”型加厚;角质膜波状有条纹,有时附有颗粒。叶表皮的一些特征对该属部分种的区分有一定的参考价值。叶表皮的微形态特征,如气孔器类型和垂周壁类型特征不能用来界定假瘤蕨属的系和亚系。     

假瘤蕨属（水龙骨科）植物叶表皮特征的比较研究

在光镜和扫描电镜下观察了假瘤蕨属2系、5亚系的24种植物的叶表皮。结果表明,叶表皮细胞形状不规则,垂周壁波曲状。下生气孔,气孔类型有极细胞型、共环极细胞型、腋下细胞型、聚腋下细胞型和不规则型,常伴生出现。在扫描电镜下,叶表皮气孔器外拱盖内缘为浅波状、少平滑;一些种的保卫细胞两端有“T”型加厚;角质膜波状有条纹,有时附有颗粒。叶表皮的一些特征对该属部分种的区分有一定的参考价值。叶表皮的微形态特征,如气孔器类型和垂周壁类型特征不能用来界定假瘤蕨属的系和亚系。     

New aspects of the morphology and function of the human hip joint ligaments.

The capsular ligaments of the human hip joint were submitted to exact morphological analysis, and they proved to be multiple and numerous. We have described various ligamentous systems and their interconnections, and have suggested new terminologies and systematics. The ligaments were subjected to functional analysis by means of measuring strips to determine the positions in which the ligaments are taut. The ligament systems were all found to serve a restrictive function, and various parts of the apparatus restricted all possible movements in the hip joint. Extension is restricted by the medial iliofemoral complex, abduction by the pubofemoral ligament, and adduction by the posterior coxal ligaments and by the superior ischiofemoral ligament. Flexion is restricted by the inferior ischiofemoral ligaments, inward rotation by the superior ischiofemoral ligament, and outward rotation by the lateral iliofemoral complex. Only the ligament of the femoral head is unable to exert a restricting function, despite reaching a state of tension in extreme adduction.     

Histochemical Detection of Arylsulfatase Activity in Sea Urchin Embryos

Localization of arylsulfatase activity in the sea urchin embryo was determined histochemically by light and electron microscopy. Histochemical observations by light microscopy revealed that the arylsulfatase activity appears after the gastrula stage and that it is restricted to the cells of the aboral ectoderm. The enzyme activity is mainly located in the apical cellular cytoplasm and is associated with lysosome-like structures that are frequently fused with yolk granules. Intense activity is also detected in the region of the endoplasmic reticulum and Golgi apparatus. No enzyme activity is found in the extracellular spaces of embryos.