bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alkaline Phosphatases and the Cycle of Nucleic Acids in the Gonads of Some Isopod Crustaceans
Authors: Nicola Marina De 
Published: April 2021

ABSTRACT
1. The distribution of alkaline phosphatases and their relation to nucleic acids have been investigated by means of Gomori’s technique in the gonads of Isopod Crustaceans (Asellus aquaticus and some Cymothoids).
2. Alkaline monophosphatases are distributed over the Feulgen-positive structures, in nucleolus, and in_the cytoplasm of young oocytes. They disappear from every place, except nucleoli, during yolk formation. The close coincidence of their localization with that of nucleic acids indicates that they are involved in the metabolism of the latter. The cytoplasmic localization is probably connected with RNA distribution only where this is being actively metabolized.
3. RNA diphosphatases have a similar distribution ; they are present where the acid is present, but they do not follow so closely its cycle. Contrary to monophosphatases, they do not disappear gradually from the cytoplasm of the oocyte, where RNA does so.
4. DNA diphosphatases are partially independent from DNA, because they are present also in some Feulgen-negative structures (cytoplasm and nucleolus). As the RNA diphosphatases, they do not disappear gradually during vitellogenesis.
5. Diphosphatases show also a depolymerizing action on DNA. It seems more likely that this fact is due to a nucleasic action intrinsic in diphosphatases than to an association of these enzymes with a nuclease.
6. The interpretation of diphosphatases as a storage of phosphorylizing enzymes in the cell is discussed.
7. The possibility that Gomori’s reaction of diphosphatases fails to show their exact localization in the cell is considered, and, as far as the present material is concerned, discarded.
Cytochemical Studies on the Embryonic Development of Drosophila melanogaster: I. Protein Sulphydryl Groups and Nucleic Acids
Authors: Yao T. 
Published: April 2021

ABSTRACT
In the egg of Drosophila the distribution of sulphydryl and ribonucleic acid compounds has no apparent connexion with the dorso-ventral organization, contrary to the situation found in the amphibian egg.
Histochemical evidence suggests that the nucleic acid metabolism of the Drosophila egg may be similar to that of the chick embryo.
During embryogenesis the contraction of the germ band can be considered as an important morphogenetic stage which marks the beginning of the histo-differentiation of all larval structures.
A Critique of the Plasmal Reaction, with Remarks on Recently Proposed Techniques
Authors: Cain A. J. 
Published: April 2021

ABSTRACT
1. The acetalphosphatides which are the precursors of the aldehydes (‘plasmal’) responsible for Feulgen’s plasmal reaction are extremely labile compounds wbich hydrolyse very rapidly in acid media, and are destroyed more or less rapidly during fixation. The liberation of aldehydes from them is catalysed by mercuric chloride.
2. Ordinary unsaturated lipoids, if exposed to air, become capable of producing a colour with Schiff’s reagent, which, unless a control section is
Cain—A Critique of the Plasmal Reaction 425
used, can be misinterpreted as a positive result for Feulgen’s plasmal reaction. Mercuric chloride has little or no influence over the oxidative rancidity of unsaturated lipoids.
3. Any technique prescribed for showing the plasmal reaction must avoid acid media and prolonged fixation and handling of the tissues. A control section is a necessity.
A Dye Phosphate for the Histo- and Cytochemical Demonstration of Alkaline Phosphatase, with some Observations on the Differential Behaviour of Nuclear and Extranuclear Enzymes
Authors: Loveless A. , Danielli J. F. 
Published: April 2021

ABSTRACT
1. A new method is described for the cyto- and histochemical demonstration of alkaline phosphatase (monoesterase), a synthetic substrate p-nitro-benzene-azo-4α-naphthol-phosphate being employed as the sodium salt. Two methods for preparing a solution of this substance are described, and optimal conditions for enzymic hydrolysis of the ester worked out by the use of kidney sections.
2. Experiments are also described” in which the substrate has been used to demonstrate phosphatase activity in calcifying tissues of dogfish and rat.
3. The results of the experiments with rat kidney indicate that traces of end-products are necessary before the enzyme can attack this substrate.
4. When results obtained with the new substrate are compared with those obtained with β-glycerophosphate, it is found that some sites display more activity towards one substrate than to the other.
5. The cytochemical localization of phosphatase with the new substrate is not as precise as with β-glycerophosphatel
On the Significance of the Plasmal Reaction
Authors: Cain A. J. 
Published: April 2021

ABSTRACT
1. Two different reactions have been confused under the name ‘plasmal’. One, the true plasmal reaction, is due, as its discoverer Feulgen showed, to the liberation of higher aliphatic aldehydes from acetalphosphatides, the reaction taking place very rapidly under the influence of mercuric chloride, the products being coloured deeply with Schiff’s reagent. The other reaction is due to the oxidation, by atmospheric oxygen, of double bonds in unsaturated fatty acid radicles. It is affected only slightly, if at all, by mercuric chloride, and increases with exposure of sections or pieces of tissue to atmospheric oxygen.
2. There is no completely satisfactory method for the histochemical demonstration of plasmal. Sections of fresh tissues are not usually suitable for cytological work, and fixation causes a reduction in intensity of the reaction. Also, the permissible fixatives are not all of the highest quality. Short fixation in a formaldehyde fixative (e.g. formal-calcium) followed by careful washing is probably the best, but the results should be compared with those obtained by the direct reaction of small pieces of fresh tissue. A suitable technique is described.
The Localization of Alkaline Phosphatase during the Post-embryonic Development of Drosophila melanogaster
Authors: Yao T. 
Published: April 2021

ABSTRACT
1. The localization of alkalii1e phosphatase during the post-embryonic development of Drosophila melanogaster has been described.
2. In the larvae, nuclear phosphatase is always demonstrable, but cytoplasmic phosphatase shows a more restricted distribution. Salivary glands, mid-gut, Malpighian tubes, and pericardial cells are richest ‘in cytoplasmic phosphatase.
3. The larva prior to puparium formation is characterized by a decrease of alkaline phosphatase in the internal organs with a simultaneous increase in the hypodermis.
4. The phosphatase data support the view that the prepupa is actually an intrapuparial larval instar.
5. Pupation is accompanied, by a very noticeable increase of alkaline phosphatase which is mainly confined to the cytoplasm. The high enzyme activity is maintained for the first day and a half after head eversion: there is a subsequent decline until at the time of emergence most organs are inactive. However, certain organs retain their alkaline phosphatase activity.
6. As in embryogenesis, alkaline phosphatase seems to be more concerned with histo-differentiation than with chemo-differentiation.
7. Alkaline phosphatase (and also acid phosphatase) actively participates in the process of histolysis or cellular degeneration.
8. The alkaline phosphatase activity of the pericardial cells, together with other morphological evidence, indicates that these cells are endocrine organs which play important roles in Drosophila metamorphosis.
9. Cytochemical evidence suggests that alkaline phosphatase in Drosophila is probably playing a part in the carriage of organic substances across the membrane barrier.
A Study of the Testis Tubules, Interstitial Tissue, and Sex Characters (Thumb-pads and Wolffian Ducts) of Normal and Hypophysectomized Frogs (Rana esculenta)
Authors: Sluiter J. W. , Oordt G. J. Van , Mighorst J. C. A. 
Published: April 2021

ABSTRACT
1. After hypophysectomy in October the testes and some sex characters (Wolffian ducts and thumb-pads) of Rana esculenta were investigated during 9 subsequent months.
2. The so-called prespermatogenesis (Champy, 1913) is completed normally after hypophysectomy, but the primary spermatogonia lose their capacity for division. Therefore 8 months after the operation the testis tubules contain only primary spermatogonia.
3. The spermatogonia of the testes of control frogs, kept under laboratory conditions from October onwards, show a precocious activity during the winter, but in July new spermatozoa have not yet been formed.
4. In both control and experimental frogs the spermatozoa, formed during late summer and autumn, almost entirely disappear in the spring, even in the absence of copulations.
5. During the winter and spring months the interstitial testis cells of the control frogs undergo a reduction in both number and function, and this coincides with the increased activity in the testis tubules which occurs under laboratory conditions.
6. Conversely the decreased spermatogenetic activity, caused by hypophysectomy, coincides with an increase in the number of interstitial cells. The cytoplasm of these cells, however, is greatly reduced, although the nuclei maintain their typical form and size till at least 9 months following the operation.
7. Thumb-pads and Wolffian ducts are strongly affected by hypophysectomy.
8. The cytological changes brought about in the interstitial cells of R. esculenta after hypophysectomy do not quite coincide with changes in the development of the thumb-pads and Wolffian ducts. Therefore no new evidence for the endocrine function of these cells can be given.
The Structure and Development of the Larval Cuticle of Diataraxia oleracea (Lepidoptera)
Authors: Way M. J. 
Published: April 2021

ABSTRACT
The main layers comprising the soft cuticle of the Diataraxia larva have been defined and a study made of their formation during development of the 5th instar larval cuticle.
In soft cuticle the epicuticle is thrown into minute tubercles and consists of three layers—the cuticulin layer, the wax layer, and the cement layer. The cement layer lies outside or partly embedded in the wax layer, but it is either absent or extremely thin over the tips of the tubercles. A polyphenol layer is absent and it is suggested that this layer is present only in hard cuticle.
Beneath the epicuticle is a thin, lightly tanned exocuticle approximately 0.5µ thick.
The 7-10p. thick outer endocuticle is perforated by well-defined pore canals and consists of lamellae containing chitin fibres varying from 100 to 2,000 A in diameter. Pore canals are absent in the inner endocuticle which when fully developed may be more than 5oµ in thickness.
At 25° C., moulting of the 4th-5th instar takes less than 48 hours. The cuticulin layer is laid down about 12-24 hours before ecdysis. At about 6-12 hours before ecdysis the exocuticle is formed beneath the cuticulin layer in the outer part of the developing outer endocuticle. Formation of the wax layer begins about 1 hour before ecdysis, while the cement layer is secreted only a few minutes prior to ecdysis. The inner endocuticle is laid down during the 5 days after ecdysis.
Prior to ecdysis the pore canals connect the hypodermis to the epicuticle and open into the exuvial cavity at the tips of the epicuticular tubercles. Probably the pore canal lumen is responsible for conduction of the moulting fluid.
Each pore canal contains a well-defined strand of material which occupies but a small part of the pore canal lumen. Thè pore canal strands, conduct protein and dihydroxyphenol from the hypodermis to form the exocuticle. Exocuticle formation is complete by about 112 days after ecdysis. At this stage the pore canal strands become chitinized and sclerotized and the pore canals are cut off from the hvpodermis by the developing inner endocuticle. The pore canals are not responsible for transport of regenerative waxes from the hypodermis after abrasion of the epicuticle.
In areas of hard cuticle there is a relatively thick and heavily tanned exocuticle which continues to develop during the life of the instar. The pore canals maintain contact with the hypodermis throughout the instar and probably remain functional as a conducting system for transport of exocuticular materials.
A study of Verson’s glands suggested that the large gland cell secretes a lipoprotein which is discharged on the surface of the epicuticle to form the cement layer. The intercalary cell secretes a phenol which is responsible for the tanning of a plug that blocks the opening of the gland duct after discharge.
Perinuclear Sudanophil Bodies in Mammalian Epidermis
Authors: Montagna William 
Published: April 2021

ABSTRACT
1. In the epidermis of laboratory mammals there are perinuclear lipid spherules which are demonstrated clearly with sudan black. The centre of the larger of these droplets is occupied by a sudanophobe core of varying dimensions.
2. The distribution of the bodies corresponds to the osmiophil elements in comparable tissues, and the structural pattern is similar to that of the Golgi elements in other tissues, as described by Baker and his associates.
3. With the exception of the skin of the monkey, the lipid bodies are negative to the acid haematein test.
A New Method for injecting the Tracheae and Tracheoles of Insects
Authors: Wigglesworth V. B. 
Published: April 2021

ABSTRACT
A simple method of evacuating and injecting the tracheal system is described.
The injection fluid consists of copper, cobalt or lead naphthenate in light petroleum (‘white spirit’). This is converted to the black metallic sulphide by exposing the insect to sulphuretted hydrogen after injection.
Tracheae and tracheoles are revealed. After fixation the tissues may be cleared and mounted in Canada balsam or sectioned and stained.
Methods of bleaching dark coloured insects after injection are described.
The Structure of the Foetal Yolk-sac Splanchnopleur of the Rabbit
Authors: Morris B. 
Published: April 2021

ABSTRACT
At the 16th day post coitum, a remnant of the bilaminar omphalopleur is present in the form of a short tag. The further shortening of this tag is effected by two concurrent processes ; firstly the degeneration at its free end, and secondly the pulling out of the ectodermal and endodermal epithelia of which it is composed. This latter process is accompanied by the further growth of mesoderm in the vicinity of the tag, and leads to the appearance of squamous cells in the endodermal epithelium of the yolk-sac splanchnopleur. The active production of multinucleate spherules by the chorionic ectoderm is decreasing in intensity by the 24th day. At this stage the vitello-allantoidean vessels in the mesoderm of the chorion, linking the omphaloidean and placental circulations, have mostly disappeared, only a few small vessels remaining. The apical concentration of the eosinophilic granules and mitochondria in the cytoplasm of the endodermal cells of the yolk-sac splanchnopleur, and the frequent basal position of the nucleus, suggests a secretory polarity. The manner in which the endodermal epithelium is folded and pleated suggests an absorptive function. On the side next to the exocoel the yolk-sac splanchnopleur is lined by a coelomic mesothelium of flattened cells which form a continuous pavement epithelium. The entry of circulating maternal antibodies into the foetal circulation is discussed.
The Effect of Inhibitory Substances on Cell Division: A Study on Living Cells in Tissue Cultures
Authors: Hughes A. F. W. 
Published: April 2021

ABSTRACT
The effect of inhibitory substances upon cell divisions in chick tissue cultures has been studied mainly by phase-contrast cine-micrography. Fluoride and powerful -SH reactants prevent the entry of cells into prophase within I hour. Aminopterin and colchicine are complete spindle inhibitors; they prevent its formation at the end of prophase, and can act on all metaphase cells in the culture. The effect of fluoride, cyanide, and urethane on the spindle is much less drastic. Most substances can retard nuclear reconstruction in telophase to some extent, but only chloracetophenone acts in the way already described for iodoacetamide. Malonate appears to have no effect on mitosis, and fluoracetate only at very high concentrations. Possible interpretations of some of these results are discussed.
Investigations of the Biology of Peranema trichophorum (Euglenineae)
Authors: Chen Y. T. 
Published: April 2021

ABSTRACT
The feeding apparatus of Peranema trichophorum, consisting of cytostome and rodorgan, is independent of the reservoir system ; the latter is the same in structure and function as that of other Euglenineae. There are two flagella, one directed forward, the other backward and adherent to the ventral body surface. The anterior flagellum is longer and thicker than the adherent one. Both flagella are composed of a central core and an outer sheath. Electron micrographs suggest that the core consists of many longitudinal fibrils, and the sheath of many short fibrils radiating from the core, giving the whole flagellum the appearance of a test-tube brush. Treatment with certain proteindispersing agents cause the unfixed anterior flagellum to dissociate into three fibrils.
Peranema multiplies freely on a diet of living yeast-cells; dead yeast is not suitable. Euglena viridis, E. gracilis, and certain other unicellular algae can also serve as food. Egg-yolk, and especially milk, can be used to maintain bacteria-free pure cultures. Casein is suitable in combination with soil-extract or beef-extract, but never as good as milk. With the latter the individuals are larger and more numerous than with yeast as food, although the cultures decline earlier. Clear liquid media of many various kinds did not support growth : particulate food seems to be essential.
Peranema is capable of ingesting a great variety of living organisms provided these are motionless. Small organisms are swallowed whole ; larger ones are either engulfed or cut open by the rod-organ and their contents sucked out. The rod-organ can be protruded out of the cytostome and used in holding on to, and cutting, the periplast of the prey. Starch-grains, oil-droplets, and protein-particles are engulfed and digested. The main food reserves are paramylon-granules and oil-droplets.
H+ ions, decomposition products of proteins, and other substances diffusing out of living, and particularly dead, organisms attract gliding Peranema. Chemotaxis plays an important role in leading Peranema to its prey.
Both gliding and swimming have been observed in normal individuals, although the latter is less frequent. While there can be no doubt that swimming results from the action of the anterior flagellum, it does not seem to play an appreciable part in gliding. Nothing is known about the function of the adherent flagellum.
The Autonomic Nervous System of the Chimaeroid Fish Hydrolagus colliei
Authors: Nicol Colin 
Published: April 2021

ABSTRACT
The autonomic nervous system of the chimaeroid fish Hydrolagus colliei has been investigated by dissections and histological methods. It consists of a cranial parasympathetic portion and a sympathetic portion confined to the trunk. The latter extends from the level of the heart to the anus and consists of segmentally arranged ganglia on each side of the dorsal aorta. These ganglia are closely associated with small accumulations of suprarenal tissue. Two axillary bodies are the largest of the sympathetic and suprarenal structures. They lie about the subclavian arteries and are made up of a gastric ganglion and a relatively large mass of chromaffin tissue. The sympathetic ganglia lie in an irregular plexus of longitudinal and crossing sympathetic strands but there is no regular sympathetic chain or commissure between ganglia. There are white rami communicantes which connect the sympathetic ganglia with spinal nerves. A small pregastric ganglion lies on the rami communicantes to the gastric ganglion. The visceral nerves arising from the sympathetic ganglia proceed to blood-vessels, genital ducts, chromaffin tissue, and gut. The latter is supplied by large splanchnic nerves which originate in the gastric ganglia and proceed along the coeliac axis to the intestine, pancreas, and liver. Prevertebral ganglia are absent. A mucosal and a submucosal plexus are present in the intestine. The cranial component of the autonomic system comprises a midbrain and a hindbrain outflow. In the former there is a ciliary ganglion on the inferior oblique branch of the oculomotor nerve. Short ciliary nerves proceed from this branch to the eyeball. A radix longa is absent. Sensory fibres go directly to the eyeball from the profundus nerve as anterior and posterior long ciliary nerves. The hindbrain outflow comprises scattered nerve-cells and ganglia on post-trematic branches of the glossopharyngeal and vagus nerves. These autonomic fibres in the branchial nerves innervate smooth muscle in the pharyngeal region. A visceral branch of the vagus innervates the heart, oesophagus, and intestine; it also establishes a connexion with the pregastric ganglion. In general, the autonomic nervous system of Hydrolagus is very similar to that of selachians. It appears that the autonomic systems of these two groups have undergone little alteration since their origin in the Palaeozoic from some common form. Their autonomic systems reflect a simple and primitive level of organization from which more complex systems of the bony fishes and amphibians have evolved.
Determination of the Form of Regenerating Limbs in Asellus aquaticus
Authors: Needham A. E. 
Published: April 2021

ABSTRACT
The nerve-supply to the regenerating anterior pleopods of Asellus aquaticus influences the rate of regeneration but not the character of the regenerate. The tissues of the locality of the blastema determine the character of the regenerate and also influence the rate and extent of regeneration. In contrast to the thoracic limbs these appendages are very sensitive to the induction of abnormalities of regeneration. The complete suppression of regeneration of a limb is the most common induced abnormality. An all- or-none effect i” evident. The development of supernumerary structures is the next most common abnormality. The re-emergence of the endopodite of the first pleopod, suppressed in normal ontogeny, is the most frequent supernumerary. It often shows homoeotic differentiation. A tendency towards bilateral symmetry is evident in all abnormalities, in spite of asymmetry in experimental treatment. Fusion of individual blastemae is not uncommon. There is no fusion with homoplastic embryonic tissue. There is no substance with the properties of a ‘wound hormone’. The regeneration of Pl. 2 in the male is more easily suppressed than that of Pl. i.