Polypeptides of the Golgi Apparatus of Neurons from Rat Brain

An antiserum was raised against fractions of the Golgi apparatus of neurons from rat brain. Immunoblots of these fractions with the antiserum showed two principal bands of 185 and 150 kilodaltons (kd) in apparent molecular mass. The antiserum reacted with five or six bands of 200, 150, 130, 100-110, 64, and 40 kd in apparent molecular mass in immunoblots of several crude brain membrane fractions. Affinity-purified antibodies from the different gel bands transferred to nitrocellulose paper were used in immunoblot and immunocytochemical studies. Antibodies eluted from the 200-, 150-, 100-110-, and 64-kd bands reacted not only with the corresponding band but also with the other three bands. Antibodies eluted from the 40-kd band stained only the corresponding band. On light and/or electron microscopic immunocytochemistry, the antiserum stained the Golgi apparatus of rat neurons, glia, liver, and kidney tubule cells. Weaker, segmented, and less consistent staining was observed in nuclear envelopes, rough endoplasmic reticulum, and plasma membranes of neurons. Antibodies eluted from the bands at 200, 150, 100-110, and 64 kd stained intermediate cisterns of the Golgi apparatus of neurons. These findings suggest that a group of related polypeptides of brain membranes is preferentially expressed or enriched in the Golgi apparatus of neurons. Polypeptides with apparent molecular masses of 185 and 150 kd probably represent moieties endogenous to membranes of the neuronal Golgi apparatus.     

Tridimensional analysis of the formation of secretory vesicles in the Golgi apparatus of absorptive columnar cells of the mouse colon

The tridimensional structure of the Golgi apparatus has been studied in the absorptive cells of the mouse colon by means of reduced osmium postfixation and phosphatase cytochemistry. In thick sections of tissue impregnated with osmium tetroxide or treated with a technique to demonstrate TPPase activity, the Golgi formed a continuous ribbon-like structure capping the upper pole of the nucleus. Along the longitudinal axis of this ribbon, compact zones made up of superposed flattened saccules alternated with less compact zones which consisted of highly perforated saccules or bridging anastomosed tubules. In the cis-trans axis, the following elements were observed: (1) a cis element consisting of a continuous osmiophilic tubular network; (2) two or three subjacent elements selectively perforated by wells; (3) a trans compartment made up of two or three TPPase-reactive sacculotubular elements, some showing a "peeling-off" configuration. In some regions, the first flattened saccule of this trans compartment displayed discrete ovoid dilatations, located in compact zones and containing a dense granulofibrillar material; in the subjacent elements this material was seen concentrated in nodular swellings, at the intersection of the meshes of anastomosed membranous tubules. 100-300 nm vesicles containing a similar dense granulofilamentous material were observed in the trans Golgi zone and interspersed in the supranuclear cytoplasm between the Golgi zone and the apical surface of the cell. Smaller vesicles 80-100 nm in diameter containing a fine dusty material were also seen in proximity. These morphological observations suggested that at least two kinds of material were segregated in the saccules of the trans compartment and packaged in vesicles of two class sizes that detached from the Golgi stack on its trans aspect.     

Effects of starvation on growth and reproductive apparatus of two immature freshwater snails Biomphalaria pfeifferi and Biomphalaria glabrata (Gastropoda: Planorbidae)

Starvation of immature snails of Biomphalaria pfeifferi and B. glabrata results in an arrest of growth and animals remain immature. Spermatogenesis is limited to spermatogonia (B.g.) or spermatocytes 1 (B.p.). The number and the size of oocytes remain inferior to that of controls. Animals show reduced genital tracts.Once feeding is restored, growth is resumed but wet weight and shell diameter do not reach the same level as in controls. Fecundity and gametogenesis do not differ from that in controls. Genital tracts weight is proportional to body weight.     

Special secretory cells in the soybean seed coat

Summary The seed coat of soybean (Glycine max L. Merr.) is of physiological interest for synthesis and transport of amino acids and photosynthates during embryo development. A transmission and scanning electron microscopic study to elucidate the structure of the seed coat disclosed a specialized convex area (antipit) appressed to a concave pit in the center of the abaxial surface of the cotyledon. The antipit, which lies on the inner surface of the seed coat at a medial point in the anterior to posterior direction of the seed, contained specialized secretory cells bounded by loose multi-layered cell walls. These cells were rectangular in the developing seed, varied in length, and contributed directly to the convex morphology of the antipit seen on the ventral surface of the seed coat. At maturity these cells assumed the shape of a cone, extending from the aleurone layer in a perpendicular array. The aleurone and cone cells contained numerous Golgi apparatus, laminated rough endoplasmic reticulum, secretory vesicles, and amyloplasts. Secretory vesicles arose directly from tubules of fenestrated trans cisternae of the Golgi apparatus. Mitochondria were clustered with the amyloplasts; stacks of lamellar cisternae of rough endoplasmic reticulum were associated with the nucleus and Golgi apparatus. The cellular contents, the interconnections by plasmodesmata, and the close physical association with the cotyledon suggested that the aleurone and cone cells may be involved in symplastic transport of nutrients for use by the developing embryo.This paper is dedicated to the memory of my parents, Joseph and Theresa Yaklich, who by their example taught me the value of work and the enjoyment of simple things.     

A cryptic cytostome is present inEuglena

Summary A short cylindrical pocket arises as an infolding from the ventral surface of the reservoir near the canal in several species ofEuglena (E. mutabilis, E. gracilis strain T,E. spec.). The structure is linked to a band of microtubules which is shown to be identical to the ventral flagellar root of the euglenoid flagellar root system. An absolute configuration analysis of the flagellar root system inE. mutabilis and a comparison with the flagellar apparatus of colourlessEuglenophyceae and the bodonids (Kinetoplastida) reveals structural and positional homology between the reservoir pocket ofEuglena and the cytostome of these organisms and strongly supports the phylogenetic derivation of theEuglenophyceae from theKinetoplastida and the evolution of greenEuglenophyceae from phagotrophic colourless taxa. The functional significance of the cryptic cytostome ofEuglena is discussed in relation to the occurrence of intracellular endosymbiotic bacteria.     

Dye-flow apparatus to measure the variation in axial xylem permeability over a stem cross-section

Abstract Equipment and methodology are described that allows the radial variation in axial xylem permeability (hydraulic conductivity) over a tree cross-section to be measured and the flow paths to be identified by the strictly controlled flow of dye through a specimen. The apparatus can be calibrated so that the point-to-point variation of absolute permeability over a xylem cross-section can be calculated from the dye-flow patterns, which otherwise show only relative variations in permeability. The effect of using different dyes and dye concentrations on the penetration time and the shape of the dye patterns was investigated. The penetration time through the wood of identical end-matched specimens is appreciably longer for fixing dyes than for non-fixing dyes, and for the fixing dyes it depends strongly on the dye concentration. However, the dye patterns of the end-matched specimens were indistinguishable with fixing and non-fixing dyes, and independent of dye concentration. The fixing dye toluidine blue at 0.25% to 0.5% (w/w) was found most suitable as it yields a clear permanent pattern.     

Fine structure of the zoospore ofUlothrix belkae with emphasis on the flagellar apparatus

Summary The anterior end of the zoospore ofUlothrix belkae has been examined in detail and is compared toStigeoclonium and other filamentous green algae. The nature of the symmetry of green algal motile cells is discussed and the term, 180° rotational symmetry, is proposed to describe the type of arrangement of anterior end components seen inU. belkae, including the four basal bodies, rootlets and striated fibers. The four microtubular rootlets are cruciately arranged. A striated microtubule-associated component (SMAC) has a periodicity of 6.4 nm and extends with each 2-membered rootlet posteriorly into the cell. One 5-membered rootlet passes very near the eyespot. Phylogeny in green algal motile cells is discussed.     

Histochemistry of the juxtaglomerular apparatus in the toad Bufo bufo

Summary An investigation regarding the question of whether there exists a macula densa as part of the juxtaglomerular apparatus in the kidney of amphibians has been carried out. With the aid of a histochemical reaction for glucose-6-phosphate dehydrogenase activity, the presence of a macula densa zone as a specialized part of the distal tubule in the toad Bufo bufo was demonstrated. The functional significance of the high glucose-6-phosphate dehydrogenase activity in the macula densa cells is discussed.     

The ultrastructure of the trophic cells of the protostelidPlanoprotθstelium aurantium

Summary The protostelidPlanoprotostelium aurantium Olive andStoianovitch has trophic cells which are either amoebae or flagellates. The general morphology and ultrastructure are consistent with what has been reported for otherEumycetozoa (protostelids, myxomycetes, and dictyostelids). The flagellar apparatus structure has the same basic pattern as that of other flagellate eumycetozoans. It shares with all these an anteriorly directed flagellum and centriole and microtubule arrays (MTA) 2–4. Unlike more primitive species which have two centrioles per flagellar apparatus,P. aurantium has only one. Also, the flagellar apparatus is independent of the nucleus inP. aurantium, not linked to it as in the primitive species. These features are useful in explaining the differences in swimming behavior betweenP. aurantium and biflagellate species. Evidence is presented to show thatP. aurantium is closely related to the non-flagellateProtostelium mycophaga Olive andStoianovitch.This research represents part of a Ph.D. dissertation presented to the University of North Carolina.