bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sheaths of the motor axons of the crab Carcinus
Authors: Horridge G. A. , Chapman R. A. 
Published: April 2021

ABSTRACT
In crab leg nerves, the largest axons, which are the motor axons usually isolated for physiological experiments, have a sheath structure which is different from that in medium sized and smaller axons of the same nerve or of any other described nerves. Axons with a diameter over 20 μ have (a) an outer sheath, about 5 μ. thick, of wellspaced layers of alternating glial cell cytoplasm and extracellular fibrous material, formed from fewer cells than there are layers, and (b) an inner sheath of elongated cells which creep along the axon longitudinally and interdigitate where they meet, as seen 2 or 3 times round the outside of the membranes of axons in cross-section. Therefore, possible channels between inner glial cells are elongated and few. On these structural grounds, together with physiological evidence, they seem unlikely to be preferred pathways of diffusion of ions in crab axons. Smaller axons have simple sheaths; some occur in groups within a fibrous sheath; the thinnest axons frequently occur in bundles and have no glial cell membrane in contact with them.
The coelomocytes of the terebellid polychaete Amphitrite johnstoni
Authors: Phillips Dales R. 
Published: April 2021

ABSTRACT
The coelomocytes of the terebellid polychaete Amphitrite johnstoni Malmgren are phagocytic and accumulate oil, glycogen, and β-carotene. They also contain haemoglobin, which is transformed to haematin by ageing cells. It is to haematin that the brown colour of some worms is due. The quantity of haemoglobin in the coelomocytes is about half that in the blood. The coelomocytes increase in number in summer during early growth of the gametes, and decrease before spawning. Measurement of the quantities of coelomocytes and of gametes, and quantitative determinations of oil and glycogen suggest that the principal function of the coelomocytes is the supply of nutrients for the gametes.
An electron microscopical study of isolated mitochondrial membranes treated with osmium tetroxide, potassium permanganate, and formaldehyde
Authors: Deutsch K. , Krause W. , Rosenthal S. 
Published: April 2021

ABSTRACT
An investigation of isolated mitochondrial membranes, fixed with osmium tetroxide, potassium permanganate, or formaldehyde, shows that a great number of small particles are attached to their surfaces. Sections of specimens fixed in potassium permanganate or osmium tetroxide appear to confirm these findings. An attempt has been made to compare these particles with the ‘elementary particles’ described by Fernández-Morán and by Green, and also with particles revealed by negative staining of mitochondrial membranes, as reported by Stoeckenius. Specimens fixed with formaldehyde, whether isolated mitochondria or material fixed in bulk, show very poor contrast in electron micrographs.
The yolk-nucleus in the oocytes of Anabas scandens (Teleostei)
Authors: Gopal Dutt N. H. 
Published: April 2021

ABSTRACT
The yolk-nucleus appears as an organelle in contact with the nucleus in the early oocyte. It is spherical and appears in fixed preparations to be composed of 3 con- centric zones. Histochemical tests indicate that it contains RNA, lipid, sulphydryl groups, carbohydrate, and certain amino-acids. It assumes a reticulate form before it finally merges with the peripheral cytoplasm. Circumstantial evidence suggests that the yolk-nucleus may be involved indirectly in vitellogenesis.
A silver-Schiff reaction for cytological studies : light microscope observations
Authors: Bryan John H. D. 
Published: April 2021

ABSTRACT
A method is presented in which a complex metal-ion (ammoniacal silver) is sub- stituted for leuco-basic fuchsin in the well-known Schiff reaction for aldehydes. The reagent is reduced to metallic silver by tissue aldehydes and submicroscopic particles of the metal are deposited at the reactive sites. When the reagent is used in the Feulgen reaction chromosomes may be ‘stained’ in a specific manner to show the localization of deoxyribonucleic acid. For such a purpose, fixation should be carried out with acetic acid and alcohol mixtures rather than with solutions containing formalin or dichromate ; these latter substances preserve more of the tissue lipids and thus complicate the issue by producing cytoplasmic staining (plasmal reaction).
A silver-aldehyde reaction for studies of chromosome ultrastructure
Authors: Bryan John H. D. , Brinkley Bill R. 
Published: April 2021

ABSTRACT
A method is presented for the visualization of structures containing deoxyribonucleic acid at the electron microscope level. This is achieved by the substitution of an ammoniacal silver reagent for leucobasic fuchsin in a Feulgen-like procedure. Tissue aldehydes reduce this reagent to metallic silver, which is deposited at the reactive sites in the form of fine particles. The particles range in size from about 4 m/x downwards to below the resolving power of the microscope used. 3 fixatives have been investigated (buffered osmium tetroxide, formalin, glutaraldehyde) and the special problems encountered with each fixative are discussed. Detailed considerations regarding the preparation and handling of this somewhat unstable staining solution have been described previously (Bryan, 1964).
Results obtained from an application of this procedure in an investigation of the ultrastructure of polytene chromosomes are also reported in detail. The fibrillar nature of these chromosomes is depicted more clearly following staining than in preparations resulting from the employment of the more conventional methods in current use. The fibrils are clearly delineated by silver particles and may be grouped into 2 classes. Thus, the finest fibrils are of about 4 mµ, diameter and they are usually associated in pairs to form units of about 10 mµ diameter. Although there is a predominant orientation of the fibrils composing individual bands, the nature of the association of the 10 mµ units which results in this is not clear. Evidence for the occurrence of similar fibrils in chromatin of interphase nuclei of mammalian origin is also presented.
Taken together, the results of the various experiments suggest that this silver procedure may be used to advantage in a wide variety of investigations concerning the ultrastructure of chromosomes and chromatin.
Fibrillogenesis in the wax-moth, Galleria mellonella
Authors: Ashhurst Doreen E. 
Published: April 2021

ABSTRACT
The fibroblasts of the pupa are characterized by the great development of the endoplasmic reticulum, which becomes dilated to form vesicles containing a rather electron-dense material which is thought to be a precursor of the collagen fibrils. Fibrils are seen within the cytoplasm of the fibroblasts ; these are about 12’5 to 20 mp in diameter and some of them show indications of banding with a periodicity between 15 and 20 mp. It is thought that these fibrils and their surrounding cytoplasm become incorporated into the fibrous connective tissue. The plasma membranes of the fibroblasts are discontinuous where they are adjacent to the fibrous tissue. The fibrils in the connective tissue are obscured by masses of mucopolysaccharide, but there are indications that these fibrils are essentially similar to the intracellular fibrils.
The processes of fibrillogenesis in the moth and in various vertebrate tissues are shown to have many features in common.
Flagellar movement of the sessile flagellates Actinomonas, Codonosiga, Monas, and Poteriodendron
Authors: Sleigh M. A. 
Published: April 2021

ABSTRACT
Water currents set up by flagellar activity are used to bring food particles to the body in each of the sessile flagellates Actinomonas, Codonosiga, Monas, and Poteriodendron. The water currents produced by the 4 organisms are all somewhat different, and, while that set up by Codonosiga is in the expected direction with water flow from the flagellar base towards the tip, the currents set up by the other 3 forms flow from the tip towards the base. In all 4 types the flagellar movements take the form of plane sinusoidal undulations propagated from the base of the flagellum towards its tip, but the different types show adaptive modifications according to the pattern of water currents required. The rates of beat of the flagellum (range 30 to 50 cycles/ sec) and the speeds of propagation of the contraction wave (range too to 600 μ/sec) did not differ sufficiently to explain different current patterns. It is suggested that the ‘unexpected’ direction of current flow in 3 of the types may be the result of the presence of flagellar mastigonemes ; these are known to be present in the chrysomonad phytoflagellates, to which group Monas and probably also Actinomonas and Poteriodendron belong. Attention is also drawn to the peculiar mode of coiling and unrolling of the flagellum of the bicoecid Poteriodendron.
Studies of differential staining with acid dyes in the human adenohypophysis
Authors: Fisher A. W. F. , Bulmer D. 
Published: April 2021

ABSTRACT
With Mallory techniques the differential staining characteristics in the human adenohypophysis are mainly dependent upon the treatment with phosphotungstic acid. Though this does not remove dye which is already bound to the acidophils it prevents the subsequent access there of anilin blue or acid fuschin, but not of orange G. The molybdenum blue reaction, used after treatment of sections with phosphomolybdic acid, shows that hexavalent molybdenum is strongly bound to the basiphils but more weakly to the acidophils; it can be inferred that phosphotungstic acid reacts with the tissues in a similar manner. Deamination, acetylation, and benzoylation produce a marked reduction in dye-binding, though the granules of the basiphils are resistant to the benzoylation. Methylation results in a marked increase in the staining of all elements. The differential effect of the phosphotungstic acid is abolished, so that the dyes are able to gain admission to the acidophils after the polyacid treatment.
The differential staining is most probably dependent upon the differing permeabilities of the tissue proteins to molecules of differing sizes, the acid fuchsin, anilin blue, and phosphotungstic acid competing with each other for basic groups. On the other hand, it is possible that phosphotungstic acid has a different type of reaction with the acidophils, involving chelate linkages to carboxyl and other groups of the tissue proteins.
The histochemistry and fine structure of the accessory nuclei in the oocyte of Bombus terrestris
Authors: Hopkins C. R. 
Published: April 2021

ABSTRACT
The accessory nuclei are present throughout vitellogenesis in the peripheral ooplasm ; they probably originate from the oocyte nucleus. Structurally they resemble nuclei and in addition their electron-dense inclusions contain RNA, possibly of nucleolar origin. They do not, however, contain chromosomal material.
During development they increase in size and multiply by equal division or by a form of terminal budding.
They do not become transformed into albuminous yolk spheres but are probably concerned with the control of albuminous yolk synthesis at the periphery of the oocyte. They remain after the termination of yolk synthesis and are associated with the formation of the vitelline membrane.
Histochemical changes correlated with reproductive activity and nutrition in the chiton, Katharina tunicata
Authors: Nimitz M. Aquinas , Giese A. C. 
Published: April 2021

ABSTRACT
The chief sites of nutrient reserves observable histochemically are the germinal epithelial cells of the gonads and storage cells of the foot and mantle ridge. The germinal epithelial cells store neutral lipid and a glycogen-like material, both of which diminish in quantity during gametogenesis. In the female the disappearance of lipid from the germinal epithelium coincides with the accumulation of lipid in the oocytes.
Special storage cells of the foot and mantle contain neutral lipid globules and minute granules (1 to 2 μ) which stain with phospholipid and protein procedures and the PAS reaction. The globules and granules are embedded in a matrix of glycogen-like material. The granules disappear from the cells two months before spawning and reappear after spawning. There is no histochemical evidence for marked utilization of lipid from the storage cells of the foot and mantle during normal gametogenesis, but these lipid depots are depleted when a period of starvation is coextensive with the 5 months of active gametogenesis. A starving animal produces fewer gametes than a normal one, but the gametes are normal in so far as can be determined histochemically.
Muscles are surrounded by a sheath of glycogen-like material which is still present after 5 months of starvation.
The connective tissue ground substance throughout the animal, the secretory cells of the glandular oviduct, the mucous cells of the intestinal valve, and the mucous cells of most of the epithelium of the foot and palliai groove have similar staining affinities. They appear to contain either neutral and unsulphated acid mucopolysaccharide or a hyaluronate-like polymer with some simple sugar residues. Certain epithelial cells of the mantle ridge and of the lateral surface of the foot secrete a sulphated acid mucopolysaccharide.
The anterior gut secretes a neutral mucopolysaccharide. Lipid droplets are found in the epithelium of the stomach and intestines, and in the ‘enzyme cells’ of the digestive gland.
A study of the histochemical demonstration of cytochrome oxidase
Authors: Butcher R. G. , Diengdoh J. V. , Chayen J. 
Published: April 2021

ABSTRACT
Burstone’s procedure for the histochemical demonstration of cytochrome oxidase has been studied and applied to sections prepared by freezing in hexane and cutting by the controlled-temperature freezing-sectioning technique. The method has been modified by the inclusion of a treatment with Lugol’s iodine to yield a stronger colour, which is stable for at least several weeks and which localizes the enzyme activity more precisely. The variants of the reaction have been compared in their effect on cardiac muscle, liver, and kidney of the rat.
The staining of degeneration in the nervous system of the octopus by modified silver methods
Authors: Lund R. D. 
Published: April 2021

ABSTRACT
The Nauta-Gygax and Glees methods used on mammalian material for demonstrating degenerating nerve fibres have been modified for similar use on Octopus vulgaris. The results compare well with the Cajal method which has been employed up to the present. Degenerating fibres stain more intensely than with the Cajal method and many of the normal fibres are differentially suppressed.
The ultrastructure of the tegument of Moniliformis dubius (Acanthocephala)
Authors: Nicholas W. L. , Mercer E. H. 
Published: April 2021

ABSTRACT
The ultrastructure of the body wall of Moniliformis dubius has been studied in the light and electron microscope. It consists of an apparently syncytial tegument, overlaid by a tenuous cuticle in the form of a finely fibrous extracellular fringe and is backed by a basement membrane and fibrous connective tissue. The tegument contains a framework of fibres, which, distally, is connected to a dense fibrous meshwork separated from the cuticle by two membranes. Within the syncytial tegument are found the usual cytoplasmic organelles : mitochondria (often degenerate in structure), Golgi clusters, small amounts of other smooth membranes, and numerous dense particles (glycogen and perhaps ribosomes). Many mitochondria contain dense particles. Evidence of vacuole formation at the surface of the tegument suggests that pinocytosis plays a part in assimilation.
The histochemical demonstration of alkaline phosphatase in unfixed frozen sections
Authors: Bitensky Lucille , Cohen S. 
Published: April 2021

ABSTRACT
Although, ideally, enzyme histochemistry should be performed on unfixed sections, so as to avoid potential artifacts inherent in chemical fixation, it is usually considered necessary to fix sections so as to stop the ‘soluble’ enzymes from becoming lost into the incubation medium. However, provided that suitable frozen sections are used, alkaline phosphatase can be demonstrated fully in unfixed sections, even though this is typically a ‘soluble’ enzyme.
The synthesis and migration of nuclear proteins during mitosis and differentiation of cells in rats
Authors: SIMS R. T. 
Published: April 2021

ABSTRACT
Hooded rats were given an intraperitoneal injection of 3H-tyrosine, and killed in pairs io min, 30 min, 12 h, 36 h, 7 days, and 30 days later. A piece of skin with white growing hair, and the tongue, were taken from each animal and radioautographs were prepared. Silver grains were counted over whole nuclei and whole mitotic figures of the germinal cells and whole nuclei of differentiating cells of both tissues. It was found that the interphase nuclei have significantly more silver grains over them than the chromosomes at all stages of mitosis and there are virtually no grains over metaphase, anaphase, and early telophase chromosomes in both tissues of all the animals killed up to 36 h after the injection. The difference between the grain counts over the interphase nuclei and the chromosomes of dividing cells is at least 20-fold at 30 min in the hair matrix, at least 5-fold at 30 min in the tongue and at 36 h in both tissues. It was established that the differences observed between the radioactivities of the nuclei and chromosomes of mitotic figures are real from estimates of : the radioactivity of the cell cytoplasm, volumes of the metaphase chromosomes and interphase nuclei within 1 μ. of the photographic emulsion, and the volumes of cytoplasm separating the photographic emulsion and these structures. No protein synthesis was demonstrable in the chromosomes during metaphase, anaphase, and early telophase. Nuclear proteins leave the chromosomes during prophase and prometaphase and return to the nucleus during late telophase. The cells in the matrix and upper bulb of the growing hair follicle and those in the germinal, prickle, and granular cell layers of the tongue are in different functional states ; 30 min after injection of 3H-tyrosine they have different amounts of it in their nuclear proteins. It is suggested that the amount incorporated into each nucleus is related to the rate at which proteins are being synthesized by the cell.
Observations on the histochemical distribution of alcohol dehydrogenase
Authors: Ferguson M. M. 
Published: April 2021

ABSTRACT
Alcohol dehydrogenase capable of utilizing primary alcohols (straight and branched chain, unsaturated and cellosolves), secondary alcohols, polyhydric alcohols but not tertiary alcohols is described in the rat brain, lung, heart, liver, kidney, gut, spleen, pancreas, uterus, and seminal vesicle. With the straight chain primary alcohols the extent to which the alcohols were used increased relative to increasing chain length until the optimum length of six to seven carbon atoms had been reached, whereafter activity decreased, probably due to the insolubility of the higher members of the series in water. Side groups on the chain, double bonds and ethereal oxygen atoms, all had the effect of hindering the ease of dehydrogenation of the alcohol. Secondary alcohols were suitable as substrates; however, tertiary alcohols did not seem to be satisfactory for the demonstration of alcohol dehydrogenase. Polyhydric alcohols were suitable substrates although they were not as well used as were the monohydric alcohols. Furfuryl alcohol dehydrogenase was found in all tissues and is apparently a separate enzyme.
The Use of Nile Blue in the Examination of Lipoids
Authors: Cain A. J. 
Published: April 2021

ABSTRACT
Nile blue, introduced by Lorrain Smith for distinguishing between neutral fats (triglycerides) and fatty acids, was considered by Lison to be of no histochemical value except that the red coloration was specific for lipoids in general. This conclusion was based principally on Lison’s own researches, and in part on those of Kaufmann and Lehmann.
Reinvestigation has shown that some of Kaufmann and Lehmann’s results are of doubtful value and all require careful interpretation, but in general these and other results lead to the conclusion that nile blue can be used to distinguish neutral lipoids (esters and hydrocarbons) from acidic lipoids (phospholipines and acids). Cholesterol is not detected.
A method for using both the oxazine and oxazone of nile blue is described, which has greater sensitivity to acidic lipoids.
A Study of the Spheroid System of Sympathetic Neurones with Special Reference to the Problem of Neurosecretion
Authors: Thomas Owen Lewis 
Published: April 2021

ABSTRACT
1. Evidence is put forward in support of the view that the Golgi complement of the vertebrate sympathetic neurone consists of a dispersed system of spherical bodies. These bodies can be studied in living cells and with vital dyes and each consists of a neutral red staining core (the vacuome of Parat) enveloped in a lipoidal sheath.
2. The classical Golgi body is shown to be an artifact produced within the cell. With the osmium techniques the spheroid bodies together with the mitochondria form a framework which serves as a centre for a non-specific deposition of metallic particles.
3. The Golgi spheroids exhibit a secretion cycle with the formation of a granular product. The granules are identified with the ‘neurosecretion’ granules of Scharrer.
4. These granules appear to be transported to the nucleus of the cell and there to be absorbed. This observed interrelationship between nucleus and Golgi product is discussed.
Observations on Hypotrichous Ciliates: The Genera Stichotricha and Chaetospira
Authors: Froud Joan 
Published: April 2021

ABSTRACT
The structure, behaviour, and asexual reproduction of a plant-cell-inhabiting hypotrichous ciliate are described. The systematic position of the ciliate is discussed and it is placed in the genus Stichotricha Petty as S. intermedia n.sp. New information concerning behaviour, nuclear apparatus, and asexual reproduction is given for the loricate Chaetospira miilleri Lachmann. Cysts are described for the first time.