bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Observations on the Cytology of the Adenohypophysis of the Non-parous Female Rabbit
Authors: Allanson M. , Foster C. L. , Menzies G. 
Published: April 2021

ABSTRACT
Evidence is presented which suggests that in this animal the pars tuberalis may have some function in addition to acting as a bed for the hypophysial portal system, since its cells appear rich in RNA.
The granules of the cells of the pars intermedia are shown to be PAS-positive, but this reaction, unlike that of the basiphil cells of the pars distalis proper and the zona tuberalis, is readily prevented by pretreatment of sections with proteolytic enzymes.
A study of the basiphil cells of the pars distalis proper and of the zona tuberalis, based on cytological characteristics, size, and shape, provides some evidence for the existence of two, and possibly three, kinds of basiphil cell.
The lipid inclusions of the adenohypophysial cells and their relationship to the Golgi elements are described, together with some brief preliminary observations upon the electron microscopic characteristics of acidophil and basiphil cells.
Further Observations on the Development of the Peptic Cells of the Rabbit’s Stomach
Authors: Menzies Gordon 
Published: April 2021

ABSTRACT
I. The loss of the mucinogen component of the peptic granules begins during the fourth week of post-natal life (400 g) at a site on or near the greater curvature of the stomach adjacent to the pyloric antrum. It reaches the lesser curvature at about the sixth week (750 g).
2. The loss progresses slowly across the ventral and dorsal walls of the stomach and more rapidly along the greater curvature.
3. At 11-12 weeks (1,800 g) only a few peptic cells on the greater curvature and adjacent to the oesophageal opening contain PAS-positive granules.
4. Except for a few granules in an occasional peptic cell, no mucinogen can be demonstrated in these cells after the fourteenth week (1,900 g).
5. The stage seems to be correlated more closely with the weight than with the age of the animals.
An Anatomical, Histological, and Histochemical Study of the Gut of the Brachiopod, Crania anomala
Authors: Chuang S. H. 
Published: April 2021

ABSTRACT
The anatomy of the gut in Crania anomala Müller was described by Joubin (1886) and Blochmann (1892), both of whom also made some observations on its histology. The present paper gives an account of the structure of the gut and the results of some histochemical tests.
The Fine Structure and Histochemistry of the Ligaments of Nephtys
Authors: Clark M. E. , Clark R. B. 
Published: April 2021

ABSTRACT
A unique ligamentary system occurs in the polychaete Nephtys. Its fine structure and physico-chemical properties have been investigated.
The ligaments consist of alternating bands of elastic and inelastic elements, and they attach to the body by means of crystalloid attachment nodes. The nodes are probably glycoprotein in nature as they contain both protein and polysaccharide. They are not birefringent, and they are insoluble in comparison with the other components of the ligaments. Their structural stability is due mainly to strong ionic and hydrogen bonding. They resist enzymatic digestion.
The inelastic elements are bundles of thin, birefringent fibrils, 10 to 14 μ in length. The birefringence is positive with respect to the long axis of the fibrils and is primarily intrinsic in nature. The estimated coefficient of birefringence has a value between 10 and 20 × 10-3. The fibrils consist of a protein with an isoelectric point near pH 6 · 3. The visible structure of the fibrils is due to both hydrogen and ionic bonding, while the birefringence is more dependent on hydrogen bonding. The fibrils resist heating and peptic digestion, but are slowly digested by trypsin. Of all the fibrous proteins, they most resemble collagen.
The elastic elements are extremely fine, granular cross-membranes bearing delicate filaments to which the ends of the fibrils are attached. They are continuous with a bounding membrane surrounding the ligament, which also bears granules and is also elastic. Some of the granules appear to be folds of the membrane itself. The membranes consist of a protein which is quickly digested by trypsin but not digested by pepsin. Its isoelectric point lies near pH 5. Hydrogen bonding is more important than ionic bonding in the membranes, and Van der Waals forces may also contribute. Classification of this protein is not yet possible.
Cyclical Changes in the Distribution of the Testis Lipids of a Seasonal Mammal (Talpa europaea)
Authors: Lofts B. 
Published: April 2021

ABSTRACT
In the mole, Talpa europaea, there occurs a sequence of interstitial events comparable with that of seasonal birds, reptiles, and some fishes. There is a periodic accumulation and discharge of cholesterol and lipids in the Leydig cytoplasm. This cycle differs from its avian counterpart in that whereas in birds (and some fishes) the Leydig cells rapidly discharge their sudanophil contents before mating, the interstitium of the mole becomes exhausted much more slowly. Another difference is that the Leydig cells of the mole do not appear to become exhausted and replaced en masse as in birds after spermatogenesis. The seasonal growth and regression of the mammalian accessory sexual organs can be correlated with the increase and decrease of secretory activity of the interstitial cells (as shown by their lipid cycle). In the seminiferous tubules of the mole there is no lipid cycle corresponding to that observed in sub-mammalian vertebrates.
The Total Solids in the A- and I-Band Regions of Living Mammalian Striated Muscle-fibres
Authors: Ross K. F. A. , Casselman W. G. B. 
Published: April 2021

ABSTRACT
Living muscle-fibres from freshly killed mice were mounted in isotonic saline /protein media and examined with a Smith interference microscope, usually with a white light-source. When the A or I bands near the edge of a fibre were observed to match the colour of the background field, their refractive indices were close to that of the mounting medium; although it is extremely probable that diffraction at the edges of the adjacent unmatched bands affected their apparent match, so that they were not exactly of this refractive index. Matched A bands were distinguished from matched I bands by examining them in plane-polarized light, by rotating the preparation through a right angle under the interference microscope to display their birefringence, and from the colour of the unmatched bands when the fringe system of the microscope was left unaltered.
In any one fibre, the refractive indices of the 71-band regions were always higher than that of the Z-band regions. The H bands had lower refractive indices than the A bands, and the Z bands higher than the I bands, but these were both too narrow to be matched satisfactorily by this method. The refractive indices of the solutions in which matched I bands were found ranged from 1·358 to 1·363, and those in which matched A bands were found from 1·360 to 1·366. The mean refractive index of the A and I bands was very close to 1·363, which is equivalent to a total solid content of 16% w/v.
These findings are in good general agreement with those of H. Huxley and Hanson (1957) and Bennett (1955), who measured the distribution of solid material in isolated glycerinated mammalian myofibrils; but the difference between the refractive indices of the A- and Z-band regions of the living fibres appeared to be very much less. Only part of this discrepancy can be accounted for by the presence of non-fibrillar solid material, because the total amount of this is extremely unlikely to exceed 50% of the total myofibrillar fibrous protein. It therefore seems probable that, because of the diffraction from the unmatched bands, the true refractive indices of the A bands were higher than those of the solutions in which they appeared matched, and those of the Z bands were correspondingly lower than those of the solutions in which they appeared matched.
The maximum error involved here (when the sarcomere interval was approximately 2·5 μ) can be quantified from independent estimations of the non-fibrillar material in whole muscle (Szent-Gyôrgyi and others, 1955; Hanson and H. Huxley, 1957); and from this it seems highly probable that the refractive indices of the I bands were not lower than 1·350 (equivalent to a solid content of 9% w/v), and those of the A bands were not higher than 1·375 (equivalent to a solid content of 23% w/v).
The Chromosome Numbers and Nuclear Cytology of some Common British Serpulids
Authors: Dasgupta S. , Austin A. P. 
Published: April 2021

ABSTRACT
The chromosome numbers of Hydroides norvegica, Mercierella enigmática, and Pomatoceros triqueter were determined from squashes of somatic cells in young embryos obtained by artificial fertilization, and stained with iron-alum/aceto-carmine. All had a diploid count of 2n = 26 chromosomes. Mitotic and meiotic divisions in the 5 species of Spirorbis examined, and in Filograna implexa, all revealed a diploid chromosome number of 2n= 20. A diploid chromosome number of 14 is suggested for the ancestral serpulid.
On the Interpretation of Phase-contrast Images
Authors: Steel W. H. , Tchan Y. T. 
Published: April 2021

ABSTRACT
It is shown that the simple theory of phase-contrast microscopy may be extended to take some account of the size of the object by the introduction of an ‘overlap factor’ which expresses the fraction of the diffracted light that passes through the phase-changing region of the phase plate. The extended theory can explain observed effects that cannot be explained even qualitatively if overlap is ignored. The overlap factor is given for disk-shaped objects and an annular phase plate.
The Fine Structure of Epithelium and Mesogloea in a Sea Anemone
Authors: Batham E. J. 
Published: April 2021

ABSTRACT
Ultra-thin sections of mesenteries of a sea anemone provisionally referred to Metridium canum have been examined in the electron microscope. The flagella show the common 9:2 fibrous structure, the peripheral fibres fusing basally and appearing to run through continuously to basal corpuscle and banded rootlet. Arising from the epithelial surface, as well as flagella, are numerous palisade processes, some radiating from flagella bases. These extensive processes show internal fibrous structure. Mesogloeal fibres show strong banding, with a period of about 42 to 46 mμ.
A Note on the Habits and Nutrition of Solemya parkinsoni (Protobranchia: Bivalvia)
Authors: Owen G. 
Published: April 2021

ABSTRACT
Adult specimens of Solemya parkinsoni Smith, embedded in mud at a depth of 50 cm or more, were collected near low water (spring tide). The animal burrows with the anterior end downwards and does not maintain an opening to the surface. An inhalant current is drawn into the mantle cavity anteriorly on each side of the foot, while an exhalant current leaves by the single, posteriorly situated aperture. This is probably a respiratory current, bottom material entering the mantle cavity as a result of the muscular activity of the mantle and foot.
The course of the alimentary canal is described, and the problem of feeding and nutrition correlated with the extreme reduction of the gut exhibited by S. parkinsoni discussed. It is suggested that an initial breakdown of organic material may take place in the mantle cavity.
On the Filamentous Elements in the Nucleoli of Chick Embryo Fibroblasts
Authors: Guttes Edmund , Guttes Sophie 
Published: April 2021

ABSTRACT
Filamentous inclusions (= nucleolonemata) in the nucleoli of chick embryo fibroblasts and their behaviour during the cellular cycle are described. Their number is about the same as that of the macrochromosomes. They originate in anaphase as thin threads along the chromosomes. During the reconstitution of the daughter nuclei they aggregate within two nucleoli. They disintegrate with the prophase of the next mitosis.
Morphological and Histochemical Studies of the Chromatoid Body in the Grass-snake, Natrix natrix
Authors: Sud Bhupinder N. 
Published: April 2021

ABSTRACT
The chromatoid body in the spermatogenesis of the grass-snake, Natrix natrix, has been studied by the use of phase-contrast microscopy, vital dyes, and histochemical tests.
It first appears during the growth of the primary spermatocyte and is also seen in the secondary spermatocyte and late spermatid, but is absent at metaphases of both the maturation divisions, in the early spermatid, and during the final stages of spermateleosis. It does not make any visible contribution to the final make-up of the spermatozoon.
In living cells it gives a very low phase change, and is not stained by neutral red or Janus green. The histochemical study reveals that it consists mainly of RNA and of proteins with abundant acidic and basic groups.
It is tentatively suggested that its function is to provide basic proteins for the final maturation of the chromatin in the nucleus of late spermatid.
Structure and Movements of Tick Spermatozoa (Arachnida, Acari)
Authors: Rothschild Lord 
Published: April 2021

ABSTRACT
1. The spermatozoa of the tick, Ornithodoros moubata, which until now have been reported to move without any apparent means of propulsion, have been examined under the light and electron microscopes.
2. The surface of the spermatozoon is covered with ridges, running parallel to the long axis of the body, 0· 30 to 0·47 μ long and 500 to 1,000 A wide.
3. In longitudinal section approximately every other ridge exhibits wave-like deformations.
4. On the basis of these sub-microscopic structures and the behaviour of polystyrene balls stuck to the surface of live spermatozoa, the hypothesis is put forward that tick spermatozoa move by propagating lateral bending waves along the ridges in an antero-posterior direction.
5. No ‘9 + 2’ or ‘9 + 9 + 2’ arrangement of fibrils has been observed anywhere in tick spermatozoa.
6. There is a striking though not complete resemblance between the sub-microscopic surface structure of tick spermatozoa and that of gregarines.
The Coelomic and Peritoneal Cell Systems of some Sabellid Polychaetes
Authors: Phillips Dales R. 
Published: April 2021

ABSTRACT
The growth and activity of the coelomic cells of Sabella spallanzanii are described. Qualitative and quantitative determinations were made throughout the year of the glycogen, oil, and pigments which they contain. The coelomic cells accumulate carotenoids, including astaxanthin. The possibility of the interconversion of glycogen and oil by the cells is discussed, and it is concluded that the coelomic cells constitute a depot for the maturation of the gametes. This system is paralleled in some other sabellids by the development of a villous peritoneum. Such tissues contrast with the chloragogen tissue in that they have no direct contact with the blood vascular system.
Morphological and Histochemical Studies of the Chromatoid Body and Related Elements in the Spermatogenesis of the Rat
Authors: Sud Bhupinder N. 
Published: April 2021

ABSTRACT
In the spermatogenesis of the rat the chromatoid body is present during the growth of the primary and secondary spermatocytes, disappears at telophase of both the meiotic divisions, and is absent during interkinesis. It is reconstructed during the early stages of spermateleosis but after the elongation and condensation of the nucleus it gradually becomes smaller and disappears. Simultaneously, in the caudal region von Ebner ‘s stainable granules appear and gradually fuse together to form a single voluminous body, Regaud ‘s sphère chromatophile, which is discarded with the residual body and is phagocytosed by the Sertoli cell.
The histochemical studies reveal that the chromatoid body, von Ebner ‘s stainable granules, and the sphère chromatophile are similar in composition. They consist mainly of RNA and proteins, and this suggests that they may be centres of protein synthesis. The RNA content of von Ebner ‘s stainable granules and the sphère chromatophile appears to be higher than that of the chromatoid body. This probably means that there is a progressive decrease in the protein component of the chromatoid material. Also there is a distinct change in the chemical composition of the protein component of the chromatin during the late stages of spermateleosis. It is tentatively suggested that the function of the chromatoid material may be to provide basic proteins for the final maturation of the chromatin of the late spermatid.
It appears that the chromatoid elements originate from the ground cytoplasm and disappear by merging into the latter.
An enigmatic granular satellite has been found associated with the chromatoid body. It differs from the latter in its chemical composition.
The action of ribonuclease on the nucleic acid system of Spirostomum ambiguutn
Authors: Dass C. M. S. , Vimala Devi R. 
Published: April 2021

ABSTRACT
The experiments described in this paper have shown that the enzyme ribonuclease (RNase) is able to enter Spirostomum ambiguum. There is a definite concentration/time relationship in the action of RNase on the ribonucleic acid (RNA) system of the organism. The rate of action of the enzyme is proportional to its concentration in the medium. At high concentration the enzyme causes instant degeneration of the cell. At lower concentrations the enzyme acts specifically on RNA present in the cytoplasm and in the macronucleus; it causes complete loss of basiphilia. Loss of basiphilia occurs first in the cytoplasm and later in the macronucleus.
The organisms after treatment with the enzyme, when transferred back to enzymefree Chalkley’s medium, regenerate RNA. The RNA appears first in the macronucleus and later in the cytoplasm.
Histochemical demonstration of certain DPN-linked dehydrogenases and of aldolase in the red and white fibres of pigeon breast-muscle
Authors: George J. C. , Talesara C. L. 
Published: April 2021

ABSTRACT
The distribution and localization-pattern of certain DPN-linked dehydrogenases (malic, lactic, D-glucose, glutamic, and a-glycerophosphate) were demonstrated histochemically in the red and white fibres of pigeon breast-muscle by using neotetrazolium as the hydrogen acceptor, under strictly anaerobic conditions. All the dehydrogenases studied showed distinctly higher enzyme activity in the narrow red fibres than in the broad white fibres. That of a-glycerophosphate was, however, found to be appreciably more abundant than other dehydrogenases in the broad fibres. A high concentration of aldolase, which forms an important link in the chain of enzymes in glycolysis, was histochemically demonstrated in the broad, white, glycogen-loaded fibres.
Neurosecretory control of ovarian development in Schistocerca gregaria
Authors: Highnam K. C. 
Published: April 2021

ABSTRACT
Cautery of the neurosecretory cells of the pars intercerebralis, or removal of the corpora cardiaca, will prevent the development of the terminal oocytes in the ovaries of the desert locust. Implantation of brains into females whose neurosecretory cells have been cauterized results in some development of the terminal oocytes. Ovariectomy of immature females causes a precocious accumulation of material in the neurosecretory system. Electrical stimulation, drastic wounding, or enforced activity of 14-day-old females reared without males brings about release of material from the neurosecretory system, and also accelerates development of the terminal oocytes. Copulation by these females also results in release of material from the neurosecretory system, and is followed by rapid terminal oocyte development. It is concluded that the neurosecretory system in Schistocerca gregaria exerts a positive control over oocyte development, and that copulation may stimulate release of material from the neurosecretory system.
Histological changes in the gut and associated tissues of Mitopus morio (Phalangiida) during digestion of lipid and carbohydrate
Authors: Phillipson John 
Published: April 2021

ABSTRACT
In Mitopus morio both lipid and glycogen are stored in the connective tissues. The lipid stores reach their maximum at approximately 48 h after feeding, whereas glycogen reaches a maximum at 12 h and then gradually disappears only to reach a second maximum at 48 h. This second maximum is probably due to the conversion of lipid and/or protein into glycogen. Glycogen formed the main storage material (on a volume basis), a result which differs from that of Kastner (1935) and Frank (1937), who regarded lipid as the main storage product. The survival periods of starved adults of M. morio are 6·4 ± 0·8 days (males) and 8·6 ± 0·6 days (females).
Breakdown and formation of connective tissue in the pupal stage of an insect
Authors: Whitten Joan M. 
Published: April 2021

ABSTRACT
Changes occurring in the connective-tissue elements in the pupae of some Diptera Cyclorrhapha are described. The larva and the adult are characterized by an organically continuous system of investing membranes. The pupa is, on the whole, characterized by the absence of investing membranes. Early in the pupa most of the larval membranes are destroyed. In some cases the associated cells also disappear; in others the cells remain. Disappearance is not simultaneous throughout an organ; usually the anterior most segments of the organ disappear first. The adult membranes are formed in the late pupa, after the processes of growth, cell-division, and differentiation are completed. Fusion of membranes would appear to result from co-ordinated secretion, and be a delicately timed process. It is suggested that the larval membranes are similarly produced in the embryo, at the end of differentiation and organ formation, and that in the case of both larva and adult, the invested cells are concerned with the secretion of, and the destruction of, the investing membranes.
A study of the fixation of the granular elements in rat pancreas
Authors: Levene C. , Feng P. 
Published: April 2021

ABSTRACT
Rat pancreases were fixed in 6 primary fixatives and 16 fixative mixtures. Paraffin sections were stained for a and zymogen granules with chromalum/haematoxylin/phloxine, and for β granules with aldehyde-fuchsin.
Fixation of α. And β granules was obtained with all fixatives containing formaldehyde or potassium dichromate. Zymogen granules were only fixed by fixatives containing formaldehyde, and then only if acetic acid was omitted.
Formaldehyde alone was adequate for fixation of a, α, and β zymogen granules. For fixation of a and (β granules only, the mixture of formaldehyde and acetic acid was preferable because the sections were technically better.
Variations in histology of abdominal stretch receptors of saturniid moths during development
Authors: Finlayson L. H. , Mowat D. J. 
Published: April 2021

ABSTRACT
In the stretch receptors of Lepidoptera there are normally two giant nuclei, but supernumerary giant nuclei are frequently present. In a study on Sarnia cynthia supernumerary giant nuclei have been found to occur most frequently in the first, second, third, and fourth abdominal segments. They are present in the larva, pupa, and adult. Small nuclei in the muscular component of the receptors are infrequent in the larva and in the fourth, fifth, and sixth abdominal segments of the adult; but in the first, second, and third abdominal segments there is an increase in small nuclei at metamorphosis. Small nuclei also multiply in the receptors of the eighth and ninth segments but these receptors degenerate. The muscular component of the receptors that metamorphose at first becomes reduced and loses its striations and then differentiates anew. In those receptors that disappear (eighth and ninth) dedifferentiation is succeeded by histolysis. A third category of nucleus, larger than the small nuclei but smaller than the giant nuclei, was found in a few receptors of larva, pupa, and adult. Such nuclei appear to be absent from the fifth and sixth segments, but they were too rare for reliable statistics to be obtained.