Chromosomes. Aging. Longevity

Investigations dealing with the characteristics of chromosomal apparatus at late stages of ontogenesis are analyzed. Both structural and functional changes in the chromosomal apparatus are observed in ageing. Some papers indicate to the association of certain variants of chromosomal polymorphism with the longevity "phenomenon".     

Ultrastructural alteration of cytolytic T lymphocytes following their interaction with target cells. I. Hypertrophy and change of orientation of the Golgi apparatus.

The ultrastructure of cytolytic T lymphocytes adhered to the surface of target cells was investigated at different periods after start of interaction. Fifteen-minute incubation led to increase of number of Golgi apparatus cisternae and vacuoles. After 30 min incubation Golgi apparatus become oriented to the contact area. If several lymphocytes adhered to one target cell the Golgi apparatus of each of them was oriented toward the contact area. If one lymphocyte adhered simultaneously to two target cells its Golgi apparatus was oriented toward both target cells. Giant Golgi apparatus vacuoles were formed 30 to 60 min later and then moved to plasma membrane of lymphocyte and then the content of those vacuoles moved to the intercellular space between a cytolytic T lymphocyte and a target cell. The period required for the hypertrophy and change of orientation of Golgi apparatus is supposed to represent the “mobilization” step of a medium-sized and small killer lymphocyte.     

An improved Method for Isolation of Rat Testis Golgi Apparatus H. H. Mollenhauer

The preparation of Golgi apparatus fractions from rat testis germ cells free from contamination by residual body fragments was accomplished by the use of the Yeda press as the homogenization device. The Golgi apparatus thus prepared retained excellent stuctural intactness. This method also allows for isolation of Golgi apparatus from single cell suspensions.     

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.     

A universal gradient apparatus for multiple organic solvents. I. Principle, construction and gradient evaluation.

The mechanical and electrical construction and the evaluation of a gradient apparatus for multiple organic solvents and other liquids is described. Special attention is given to the problems of organic resistance, solvent density and evaporation. The apparatus is a solvent-resistant liquid pump with a positively controlled adjustable and reproducible flowrate.     

Cell-free transfer of membrane lipids. Evidence for lipid processing

A latent phospholipase A is concentrated in cis elements of rat liver Golgi apparatus, the presumed sites of fusion of the 50-70-nm transition vesicles formed from endoplasmic reticulum. As a result, conversion of transferred phospholipids to their corresponding lysoforms may provide an index of post transfer lipid processing in a corresponding reconstituted membrane transfer system. To label the phosphatidylcholine of transitional endoplasmic reticulum in vitro, [14C]CDP-choline and endogenous cytidyltransferases were used. In the reconstituted transfer system, the radiolabeled phosphatidylcholine was transferred via transition vesicles to Golgi apparatus immobilized on nitrocellulose strips in a time- and temperature-dependent process. Transfer was promoted by ATP and the ATP-dependent transfer was specific for cis Golgi apparatus elements as acceptor. Trans Golgi apparatus elements were ineffective as acceptors. Median Golgi apparatus elements were intermediate. A portion of the transferred phosphatidylcholine was converted subsequently to lysophosphatidylcholine also in a time- and ATP-dependent manner. The phospholipase A activity of the Golgi apparatus was more than 90% latent (active site located on the lumens of the Golgi apparatus membranes). Therefore, the lipid-containing vesicles derived from endoplasmic reticulum must have combined with cis Golgi apparatus membranes as the basis for Golgi apparatus-dependent phospholipase A processing of endoplasmic reticulum-derived phosphatidylcholine. Since the lipids were processed by phospholipase A in approximately the same proportion as occurs in situ, the findings offer evidence both for the specificity of the ATP-dependent component of cell-free lipid transfer from endoplasmic reticulum to Golgi apparatus and its fidelity to lipid transfer observed in vivo.     

COMPARATIVE ANALYSES OF THE DINOFLAGELLATE FLAGELLAR APPARATUS. II. CERATIUM HIRUNDINELLA1

The three-dimensional structure of the flagellar apparatus in the gonyaulacoid dinoflagellate. Ceratium hirundinella var. furcoïdes (Schröder) Hub.-Pest. was determined using serial section electron microscopy. The flagellar apparatus is quite large and consists of several components. The two basal bodies nearly abut at their proximal ends and are separated by an angle of approximately 120° The broad longitudinal microtubular root extends from the cell's left edge of the longitudinal basal body and bends around the sulcal/cingular depression into the cell's left antapical horn. A transverse striated fibrous root is associated with the transverse basal body and a narrow electron dense extension is present along the anterior edge of the transverse basal body. This study revealed severa1 hitherto unreported fibrous components of the flagellar apparatus that link the various microtubular and fibrous components to themselves and to the two striated collars. A large striated fibrous connective links the two striated collars to one another. This fibrous connective is linked to another striated fibrous connective that originates from the longitudinal basal body and lies perpendicular to the longitudinal microtubular root. The readily identifiable and numerous components of the Ceratium flagellar apparatus are comparable to those of other dinoflagellates. The combined presence of well dpveloped striated collars, a striated collar connective, and a basal body angle of approximately 120° indicates that this flagellar apparatus is most like that described for Peridinioid dinoflagellates. Important similarities are also noticeable between this flagellar apparatus and that of Oxyrrhis marina.     

Membrane trafficking in neurons.

Neurons possess an unusually extensive Golgi apparatus and exhibit a variety of active endocytic-like processes. The Golgi apparatus and the endocytic phenomena both contribute, probably in multiple overlapping ways, to the genesis and fate of the membrane systems in axons and terminals.     

STRUCTURE AND SIGNIFICANCE OF THE CRYPTOMONAD FLAGELLAR APPARATUS. I. CRYPTOMONAS OVATA (CRYPTOPHYTA)1

The absolute configuration of the flagellar apparatus in Cryptomonas ovata has been elucidated and found to be similar to that reported for Chilomonas paramecium. Variations apparent in the flagellar apparatus of Cryptomonas ovata include the presence of striations in the mitochondrion associated lamella, a rhizostyle which does not bear wing-like extensions from the microtubules and does not lie close to the nucleus, and a striated fibrous anchoring structure associated with one basal body which has not hitherto been described. The flagellar apparatus also includes a four stranded microtubular root which traverses into the anterior dorsal lobe of the cell, a striated fibrous root which is associated with a five stranded microtubular root, and a two stranded Cr root. The homologous nature of these roots to those in the larger cryptomonads is discussed in relation to the apparent reduction in flagellar apparatus size and complexity among the smaller cryptomonads. A diagrammatic reconstruction of the flagellar apparatus of Cryptomonas ovata is also presented.     

THE FLAGELLAR APPARATUS OF GYMNODINIUM SP. (DINOPHYCEAE)1

The detailed structure of the flagellar apparatus has been determined in a small dinoflagellate of the genus Gymnodinium. Although diminutive, this dinoflagellate possesses a complex flagellar apparatus consisting of a posteriorly directed microtubular root, a transverse striated fibrous root, several striated fibrous connectives that attach the basal bodies to one another as well as to the different roots, and a conspicuous non-striated fibrous connective that directly links the posteriorly directded microtubular root with the extended lobe of the nucleus. This represents the second discovery of a nuclear connective linked to the flagellar apparatus in the Dinophyceae but is the first report to elucidate the spatial relationships of the connective with the flagellar apparatus and the cell. A detailed diagrammatic reconstruction is provided and the similarities between these flagellar apparatus features are compared with those known for other dinoflagellates. Additionally, the structure and displacement of the nuclear connective are compared with nuclear connectives described in other protists.     

Stomatogenic events accompanying binary fission in Blepharisma.

Stomatogenesis was studied in the heterotrich ciliate Blepharisma japonicum stained with protargol. During binary fission not only is a new oral apparatus made for the posterior daughter, but the already existing oral apparatus of the parent cell is reorganized, i.e., partially disassembled and then subsequently reassembled to provide a functional feeding apparatus for the anterior daughter cell. These morphogenetic events, requiring 2 1/2 to 3 hr, are complete by the time the anterior and posterior daughters separate. In preparation for division, an oral anlage is formed by the rapid proliferation of kinetosomes along 4-5 stomatogenic kinetics directly subtending the cytostome. This field of randomly oriented kinetosomes ultimately gives rise to the feeding apparatus of the posterior daughter cell. Early in division, the oral anlage separates into 2 longitudinal fields of kinetosomes: one is destined to give rise to the undulating membrane and the other forms the adoral zone of membranelles. Shorly after the anlage is established posterior to the cytostome, reorganization of the existing functional mouth is initiated. The morphologic changes associated with this dedifferentiation-redifferentiation sequence lead to the formation of an oral apparatus for the anterior daughter and cannot be distinguished from those characteristically seen during physiologic reorganization.     

Lipoprotein secretion by rat liver Golgi apparatus. Lipoprotein particles and lipase activity.

Lipoprotein particles of the size range of very low density lipoproteins in smooth endoplasmic reticulum, peripheral elements of the Golgi apparatus, and secretory vesicles of the immature Golgi apparatus face are 55 to 80 nm in diameter. Particles in mature secretory vesicles are smaller (45 nm). Concomitant with the change in particle size, the lumina of mature vesicles increase in electron density. A technique to fractionate immature and mature secretory vesicles was based on precipitation of a cupric-ferrocyanide complex (Hatchett's brown) through the action of a NADH-ferricyanide oxido-reductase resistant to glutaraldehyde which is characteristic of the membranes of mature secretory vesicles and of the plasma membrane of liver. Mature secretory vesicle fractions so isolated were enriched in cholesterol and depleted in triglycerides relative to immature vesicles on a phospholipid basis. Lipase activity was present in secretory vesicle fractions of the Golgi apparatus as shown by biochemical analysis and by cytochemistry. Cytochemical studies showed lipase to be present in both mature and immature vesicles but most evident in immature vesicles. The findings suggest that some very low density lipoprotein particles are converted to particles of smaller diameter during transit through Golgi apparatus. A lipase-mediated hydrolysis of triglycerides may relate to the transformation.     

A versatile primate cage for a multiple use facility.

A mobile-transport-squeeze cage for primates was constructed. The cage contained a clear plastic guillotine door, squeeze apparatus, ventilation holes and locking casters. The squeeze apparatus could be operated by one person.     

Radiobiology of alpha particles. I. Exposure system and dosimetry

A 238Pu alpha-particle exposure apparatus was designed and constructed for use in radiobiological studies with cultured cell systems. The system provides a wide dynamic range of absorbed doses and a uniform radiation field. Average dose rate in air was measured with a small-volume ionization chamber. Estimates of dose rate at the cell surface were obtained from measurements taken with a silicon surface barrier detector. Particle fluence uniformity and fluence rate were measured using track etch procedures. The design and dosimetric characterization of the apparatus are discussed.     

Studies on woloszynskioid dinoflagellates V. Ultrastructure of Biecheleriopsis gen. nov., with description of Biecheleriopsis adriatica sp. nov.

An isolate of the very small marine dinoflagellate Biecheleriopsis adriatica gen. et sp. nov. (12–15 µm long) has been examined by light, scanning and transmission electron microscopy, combined with partial sequencing of nuclear-encoded large subunit rRNA. Biecheleriopsis is a genus of thin-walled dinoflagellates, related to Biecheleria and the taxonomic group of Polarella , Protodinium and Symbiodinium , the latter comprising mainly symbionts of marine invertebrates. The mixotrophic Biecheleriopsis adriatica is characterized by: (i) a special type of apical furrow apparatus; (ii) an eyespot of Type E sensu Moestrup and Daugbjerg; (iii) an unusual type of pyrenoid; and (iv) a spiny resting cyst. Thin sections showed the presence a fibrous connection between the flagellar apparatus and a finger-like extension of the nucleus ('rhizoplast'). It forms a physical connection between the flagella and the nucleus. This unusual structure has previously been considered to characterize the 'true' gymnodinioids, represented by Gymnodinium sensu Daugbjerg et al. and related forms. However, the apical furrow apparatus and the nuclear envelope of Biecheleriopsis are woloszynskioid rather than gymnodinioid. The related genus Biecheleria lacks a rhizoplast, and it also lacks a 51-base pair fragment of domain D2 of the large subunit rRNA, which is present in other woloszynskioids. A physical connection between the flagellar apparatus and the nucleus mediated by a fibrous structure is known in other groups of protists, for example, the 'rhizoplast' of many heterokont flagellates, some green algal flagellates, etc. The phylogenetic significance of a rhizoplast in two groups of dinoflagellates that are only distantly related is presently difficult to assess.     

Analytical scanning isoelectrofocusing. 4. Design and operation of a column-filling apparatus

An apparatus was designed and constructed for filling an analytical isoelectrofocusing column in sequence with electrolytes, sucrose density gradient and sample. The column-filling apparatus (CFA) consists of a series of valves and syringes, a density gradient mixer, a syringe microburet operated at constant speed, and Teflon tubing. The sample is injected at any position of the density gradient with a microliter syringe through an injection port. Possibilities for complete automation of this device are discussed.     

A gradient titration apparatus for determining spectrophotometric binding isotherms.

The construction of an automatic gradient titration apparatus using a multichannel peristaltic pump and a recording spectrophotometer is described. The ability of the apparatus to faithfully generate continuous spectrophotometric binding isotherms was tested in experiments studying the interaction of DNA with neutral red. The method has been shown to require low volumes of reactants, and complete binding curves can be produced in less than 15 min. The apparatus was also used to perform automatically the method of continuous variations in experiments determining the binding stoichiometry of calmagite and magnesium ion.     

A compact apparatus for vertical gel slab isoelectric focusing: resolution of rabbit anti-pneumococcal polysaccharide antibodies.

A compact apparatus for analytical and preparative vertical gel slab isoelectric focusing is described. The apparatus was extremely versatile, easy to use, and comparatively inexpensive. The apparatus was useful to compare the electrofocusing patterns of anti-pneumococcal polysaccharide antibodies from several different restricted and partially restricted rabbit responders.     

tRNAs in the spotlight during protein biosynthesis.

High resolution crystal structures of the ribosome provide fascinating insights into perhaps the most sophisticated machine of a cell. Yet, this translational apparatus must have developed from a much more primitive structure. Throughout the evolution of this apparatus, tRNAs have been, and still are, key players in the translation process.     

An Ultrastructural Study of Lentomonas applanatum (Preisig) N. G. (Euglenida)

ABSTRACT. Lentomonas applanatum (syn. Entosiphon applanatum Preisig) is a biflagellate, phagotrophic euglenid found in intertidal salt marshes. Lentomonas applanatum bears a superficial similarity to Entosiphon sulcatum , however, an ultrastructural study of L. applanatum revealed many features that are atypical for other described species of the genus Entosiphon . These features include number and organization of pellicular strips, construction of the feeding apparatus, nature of the flagellar transition zone and flagellar apparatus, and point of flagellar emergence. These differences show that L. applanatum is related more closely to phagotrophic genera such as Ploeotia than to E. sulcatum . The construction of the feeding apparatus and pellicle suggest that L. applanatum has retained many of the pleisiomorphic characters that were present in the earliest euglenids. The presence of similar structures in other related protists may provide important clues as to the evolution of the Euglenida.