bluuebunny/crossref_metadata_2025_split huggingface dataset:
Red blood cell adhesion: I. determination of the ionic conditions for adhesion to an oil-water interface
Authors: Todd Ian , Gingell David 
Published: April 2021

ABSTRACT
We have examined the adhesion of glutaraldehyde-treated human red blood cells to a clean liquid hydrocarbon interface as a function of sodium chloride concentration. Cells adhere reversibly to the interface over a wide range of concentrations but fail to do so below about 0·1 mM. Adherent cells do not alter the tension of the oil/water interface.
These results show that cells can adhere by physical forces in special situations without biochemical interactions. The data provide a basis for calculating the size of the physical forces.
Biochemical and ultrastructural studies on flight muscle mitochondria from the blowfly Calliphora erythrocephala following treatment by chloramphenicol and ethidium bromide
Authors: Ashour Badr , Tribe Michael , Danks Susan , Whittaker Peter 
Published: April 2021

ABSTRACT
Adult blowflies were injected during the first day after eclosion with various concentrations of the drugs chloramphenicol and ethidium bromide. Previous experiments had shown that these drugs inhibit mitochondrial protein synthesis and at high doses increase mortality.
Mitochondria isolated from blowflies 24 h after drug injection revealed a considerable decrease in oxidation rates when pyruvate plus proline were used as substrates. There was also a reduction up to 50 % in the respiratory control ratios obtained, though there was little change in the measurable ADP:O ratios. This loss in activity was commensurate with the finding that both drugs block the rapid increase in protein synthesis (expressed as mitochondrial protein content) during the period of observation. Examination of the cytochrome difference spectra 24 h after treatment again showed a decline in all major cytochrome peaks with increasing concentration of both drugs.
Examination of mitochondrial morphology in situ using electron microscopy revealed degenerative changes 24 h after treatment with high doses of both drugs. In particular, irregular alignment of cristae and extensive vacuolation were observed within the mitochondria.
The extent of decreased biochemical activity and morphological damage to mitochondria was clearly dependent on the concentration of drugs administered and such changes may be attributed primarily to a loss of certain polypeptide subunits coded for by mitochondrial DNA and synthesized on mitochondrial ribosomes.
Calcium-dependent shortening of fibroblasts induced by the ionophore, a23187
Authors: Goldfine S. M. , Schroter E. H. , Izzard C. S. 
Published: April 2021

ABSTRACT
Attached, spread, chick heart fibroblasts were induced to shorten by treatment with the ionophore, A23187. The shortening resulted from the retraction of the leading lamellae and other major cell processes. The response was dependent on external calcium with a threshold close to, and a maximal effect at, physiological concentrations. The shortening was also induced in Colcemid-treated cells and therefore did not involve a depolymerization of microtubules. Indirect evidence indicates that the shortening was preceded by an increase in tension in the spread cell. The response is consistent with the effect of an increase in the cytoplasmic concentration of free calcium on a calcium-sensitive actomyosin system in the spread fibroblast. Although the retraction of non-spreading processes mimicked the intermittent retraction of similar trailing processes during normal movement of fibroblasts, the response to the ionophore differed in that the leading lamellae were also induced to retract. This difference implies that a general increase in the cytoplasmic concentration of free calcium alone cannot account for the intermittent shortening that occurs in normal movement.
Dependence of cell-type proportioning and sorting on cell cycle phase in Dictyostelium discoideum
Authors: Weijer Corneeis J. , Duschl Gertrud , David Charles N. 
Published: April 2021

ABSTRACT
The relationship between the cell cycle phase of vegetative amoebae and prestalk and prespore differentiation in the slug stage were investigated in the slime mould Dictyostelium discoideum. Cells were synchronized by release from the stationary phase. Samples were taken at various times during the course of a synchronous cell doubling, fluorescently labelled and mixed with cells of random cell cycle phase from exponentially growing cultures. The fate of the fluorescently labelled cells was recorded at the slug stage. Cells early in the cycle exhibit strong prestalk sorting; cells taken later in the cycle exhibit strong prespore sorting. The period of prestalk sorting occurs immediately following mitosis and lasts about 1 h in a cell cycle of about 7 h duration. Accompanying the altered sorting behaviour is a marked change in the prestalk-prespore proportions in slugs formed from synchronized populations of cells. Cells synchronized early in the cycle form slugs with 55% prespore cells; cells synchronized late in the cycle form slugs with 90% prespore. The results are discussed in terms of models for the formation of the prestalk-prespore pattern in slugs.
Effect of substrate composition on bone resorption by rabbit osteoclasts
Authors: Chambers T. J. , Thomson B. M. , Fuller K. 
Published: April 2021

ABSTRACT
Slices of human femoral cortical bone were prepared with a carborundum wheel. Osteoclasts were isolated from neonatal rabbit long bones and incubated on either untreated, demineralized or anorganic preparations of these bone slices. Anorganic bone showed extensive tracts of uninterrupted surface excavation after incubation, while untreated bone tended to show discontinuous excavations of smaller total volume; demineralized bone was not resorbed. The endosteal surface of adult rat calvaria was also used as a substrate for osteoclastic bone resorption. The endosteal surface was exposed and rendered acellular, and was used either without further treatment or after incubation in collagenase. Bone resorption occurred only in those calvaria pre-treated with collagenase.
These experiments imply that osteoclastic contact with bone mineral rather than the endosteal surface is the stimulus that initiates bone-resorptive behaviour in osteoclasts. The mechanism by which osteoblasts induce osteoclastic bone resorption may be through the known ability of osteoblasts to secrete collagenase, which, by digestion of the unmineralized lamina limitans of endosteal surfaces, exposes bone mineral to osteoclastic contact.
Glial toxin effect on protein synthesis in an insect connective
Authors: Smith P. J. S. , Howes E. A. 
Published: April 2021

ABSTRACT
Analysis of electron autoradiographs from the nerve cord of the insect, Periplaneta americana (L.) shows a significant incorporation of 3H-labelled protein in the axons. The axonal activity is greatly reduced after treatment of the cord with the glial toxin ethidium bromide. This is interpreted as substantiating the possibility that adaxonal glia can transfer proteins to the axons.
Phorbol esters stimulate macropinocytosis and solute flow through macrophages
Authors: Swanson Joel A. 
Published: April 2021

ABSTRACT
The morphology and kinetics of pinocytosis by bone marrow-derived macrophages were studied to determine how stimulation by phorbol esters increases net solute accumulation. Application of phorbol myristate acetate (PMA) increased both the abundance of macropinosomes and the rate of solute flow through the endocytic compartment. The large pinosomes originated as ruffles at the cell margins that folded back on themselves, internalizing extracellular medium and solutes. I examined how stimulation affects the kinetics of pinocytic influx, accumulation, and subsequent efflux of the fluorescent dye Lucifer Yellow (LY) in macrophages. Both the accumulation of LY and its subsequent efflux were temperature-dependent and directly proportional to the concentration of LY in the extracellular medium. Macrophages incubated in PMA and LY for 2 h accumulated four to six times more LY than did macrophages in LY alone. If after pinocytosis the macrophages were washed and reincubated in unlabeled medium for a 1h chase period, some of the internalized LY was regurgitated from the cells. Inclusion of PMA in the chase medium increased efflux of LY. In contrast, a smaller percentage of LY was regurgitated from macrophages which were both loaded and chased in the presence of PMA. This indicates that although efflux is increased by PMA, influx increases more, and therefore more of the LY entering by pinocytosis is retained within the cell. I suggest that macropinocytosis increases the size difference between pinosomes and efflux vesicles, and that that difference increases greatly both solute accumulation and membrane flow through the endocytic compartment.
Biochemical and immunocytochemical analysis of a histone H1 variant from the mouse testis
Authors: Rasheed B. K. A. , Whisenant E. C. , Ghai R. D. , Papaioannou V. E. , Bhatnagar Y. M. 
Published: April 2021

ABSTRACT
An Hl histone variant, H1a, has been isolated and purified from the mouse testis. Biochemical and amino acid analyses indicate its similarity with the rat testis H1a. Specific antibodies against the purified H1a have been generated in rabbits and used to study its tissue and species distribution using protein blotting procedures. We have also used the immunocytochemical technique to determine in situ distribution of H1a in spermatogenic cells and somatic tissues of the mouse. A non-random distribution of H1a has been noted in the nuclei of certain somatic cell types such as Sertoli cells, Leydig cells and neurons. By contrast, hepatocyte nuclei lacked detectable levels of H1a. In adult seminiferous tubules, the early primary spermatocyte nuclei displayed a greater level of immunoreactivity relative to other cell types. Developmental studies indicate its initial expression in the 7-day-old mouse testis concomitant with the appearance of intermediate and type B spermatogonia.
Immunocytochemical study of the formation of striated rootlets during ciliogenesis in quail oviduct
Authors: Lemullois Michel , Marty Marie-Chantal 
Published: April 2021

ABSTRACT
In quail oviduct, a 175K (K=103Mr) protein associated with striated rootlets was previously identified by Klotz and co-workers using monoclonal antibody CC310. As this monoclonal antibody recognizes several proteins on immunoblots of ciliated cells, we prepared a polyclonal antibody monospecific to the 175K protein by intrasplenic immunization of mice. Immunofluorescence study confirmed the distribution of the 175K protein at the apical part of the ciliated cell and its absence in other epithelial cells. Immunogold staining showed that this protein was strongly associated with the fibrillar axis of striated rootlets. The absence of labeling on striation suggested that rootlets were composed of several proteins, with one group forming the fibrillar axis and the second forming the striation. The formation of striated rootlets during ciliogenesis was studied using this polyclonal antibody. The 175K protein appeared at the beginning of centriologenesis in fibrillar material located around dense granules, and then around the generative complex. The formation of rootlets began at the basal pole of migrating basal bodies. The elongation of the rootlet axes took place when basal bodies were anchored to the plasma membrane.
Macrophage heterogeneity in bone marrow culture in vitro
Authors: Mori Masaharu , Sadahira Yoshito , Kawasaki Seiji , Hayashi Toshiko , Awai Michiyasu 
Published: April 2021

ABSTRACT
Macrophages in mouse bone marrow cultures were investigated with macrophage-specific monoclonal antibody F4/80 and anti-Forssman glycosphingolipid (GSL) antibody, which was specific for macrophages in hematopoietic foci. Antibody F4/80 stained two types of cells, small macrophages and large flat macrophages associated with hematopoietic cells. The cytochemical and phagocytotic characteristics were similar between these two types of cells, but Forssman GSL was positive only for the large flat macrophages associated with hematopoietic cells. The data suggest that Forssman GSL positive macrophages, derived from resident bone marrow macrophages, play an important role in hematopoiesis and are clearly distinguished from small macrophages in vitro.
Microtubule-determined plastid distribution during microsporogenesis in Lilium longiflorum
Authors: Tanaka Ichiro 
Published: April 2021

ABSTRACT
The relationship between organelle distribution and the cytoskeleton was examined during microsporogenesis in Lilium longiflorum. The distribution pattern of plastid and mitochondrial nucleoids was followed by fluorescence microscopy after staining with 4’,6-diamidino-2-phenylindoie (DAPI). Although the plastid nucleoids gradually enlarged during prophase I, by anaphase I of meiosis they were randomly distributed in the cytoplasm of each microsporocyte. At telophase I the plastid nucleoids were aggregated in the equatorial region of the cell. After entering prophase II the plastid nucleoids were randomly distributed in the cytoplasm, and at telophase II they had reaggregated to the equators of the two cells. After the completion of meiosis they were located at the two poles of each young microspore. This distinct cell polarity of plastid nucleoids was preserved in isolated protoplasts. In all cells where the distribution of plastid nucleoids was non-random, the nucleoids were invariably situated furthest away from the interphase and telophase nuclei. However, the distribution of mitochondrial nucleoids throughout meiotic division showed little cell polarity.
Analysis of the microtubule and actin cytoskeletons during microsporogenesis revealed that the microtubules radiated out from the cell nuclei only at the stages when the distribution of plastids showed polarity, whereas the actin filaments were usually randomly oriented throughout the cytoplasm, independent of the plastid arrangement and of the organization of microtubule cytoskeleton. The radiating microtubules seemed to exclude the plastids from around the cell nuclei. Treatment of cultured pollen tetrads with colchicine disrupted the plastid polarity, probably by depolymerizing the radiating microtubules, resulting in a random distribution of the plastid nucleoids. Treatment with cytochalasin B, however, had no effect on the arrangement of plastids.
These results demonstrate that microtubules function in the movement and distribution of plastids in male reproductive cells of higher plants. Further, it is assumed that the system of radiating microtubules that controls the distribution of plastids during male meiosis is also involved in the subsequent formation of male gametes, which are deficient in plastids in many angiosperm plants, including this lily.
Photoreception of Paramecium cilia: localization of photosensitivity and binding with anti-frog-rhodopsin IgG
Authors: Nakaoka Yasuo , Tokioka Ryo , Shinozawa Takao , Fujita Jun 
Published: April 2021

ABSTRACT
Paramecium bursaria is photosensitive and accumulates in a lighted area. The cells can be deciliated by a brief suspension in dilute ethanol. Both intact and deciliated cells showed depolarization in response to light stimulation by a step-increase from dark to above 0.7 mW cm−2 (550 nm). On the other hand, after a step-increase to below 0·4mWcm−1, intact cells showed hyperpolarization, while the deciliated cells showed no change in membrane potential. This difference in membrane potential response between ciliated and deciliated cells suggests that both somatic and ciliary structures are photosensitive. In our search for the photoreceptive molecules, a polyclonal antibody induced in rabbits against frog rhodopsin was found to croos-react with a 63 × 103Mτ protein of P. bursaria, by Immunoelectrophoresis. Immunocytochemical studies showed that the antibody labeling was localized on both the ciliary and the somatic membranes. These results raise the possibility that P. bursaria may contain a rhodopsin-like protein as a photoreceptor molecule.
Introduction to the study of the foraminifera
Authors: Carpenter W. B. , Parker W. R. , Jones T. Rupert , Hardwicke R. 
Published: April 2021

ABSTRACT
After the lapse of five years Dr. Carpenter follows with his promised introduction to Professor Williamson’s recent ‘Foraminifcra.’ The subscribers to the Ray Society, like other unreasonable people, have undoubtedly complained of the delay. But no one, we think, who understands the nature of scientific research will feel that the subscribers to the Ray Society have lost anything. To be sure, five years makes a large vacancy in any man’s existence, but then, when it has been industriously used, what may not be the advantage ? That the five years have been employed to the advantage of the members of the Ray Society and the readers, we leave Dr. Carpenter himself to set forth :
Observations and reflections on the appendages and on the nervous system of apus cancriformis
Authors: Lankester E. Ray 
Published: April 2021

ABSTRACT
Apus Cancriformis is in many respects one of the most important of the Crustacea. Not only is it of exceptionally large size for one of the Entomostraca, and therefore suited to anatomical investigation, but it possesses peculiarities of organisation which mark it out (together with its immediate congeners, the Phyllopoda) as an archaic form, probably standing nearer to the extinct ancestors of the Crustacea than any other living members of the group.
Note on the Development of Amphibians, chiefly concerning the Central Nervous System; with Additional Observations on the Hypophysis, Mouth, and the Appendages and Skeleton of the Head
Authors: Orr Henry 
Published: April 2021

ABSTRACT
The material for the investigations which are described in this article was collected at Princeton, N.J., except a few specimens of Triton alpinus kindly given me by Professor H. F. Osborn. Through a failure to obtain adult specimens at the time when I obtained the embryos, there remains room for doubt as to the exact species of the embryos. The Ambly-stoma embryos correspond exactly to Clarke’s1 description of the embryos of Amblystoma punctatum, but there is one difference in the appearance of the egg-membranes which leads me to think that this may be a different species from that described by Clarke. It is, perhaps, A. bicolor, for which Jordan2 gives only the habitat New Jersey. The Frog embryos are either Rana halecina or R. palustris. I judge them to be the former. In the stages of development with which my work has dealt there are probably no specific differences in the embryos.
The Structure and Development of the Hairs of Monotremes and Marsupials: Part I.—Monotremes
Authors: Spencer Baldwin , Sweet Georgina 
Published: April 2021

ABSTRACT
IN his paper dealing with the structure of the bill and hairs of Ornithorhynchus,1 Mr. Poulton has described the structure of the hair in an embryo of Ornithorhynchus measuring 8·3 cm. long, in which the larger hairs had appeared above the surface of the skin. Thanks to the kindness of Professor J. T. Wilson, of Sydney, we have been able to study much earlier stages as developed in an embryo measuring 40 mm. in length, the same embryo upon which he and Dr. Martin have already worked when studying the structure of the bill. To Mr. Dudley le Souef we are indebted for an embryo measuring 77 cm., in which the hairs have not yet appeared above the surface, and to Dr. Gregg Wilson for pieces of skin of an embryo of the same age. In the case of Echidna we have been able to study the structure of an embryo measuring 55 mm. in length in which the tips of the larger hairs, which subsequently become modified into spines, have just appeared above the surface, and we are again indebted to Dr. Gregg Wilson for pieces of skin of an embryo of the same age. Owing to the fact that in different parts of the body the hairs are not all developed to the same extent, we have been able to study various stages—in the youngest one of which the follicle is only just formed, while in the oldest the largest hairs are well developed.
Hydroids from Wood’s Holl, Mass. Hypolytus peregrinus, a New Unattached Marine Hydroid: Corynitis Agassizii and its Medusa
Authors: Murbach L. 
Published: April 2021

ABSTRACT
During the last part of the summer of 1895, while searching for the larvae of Gonionemus1 in tow and dredgings from the eel pond at Wood’s Holl, a curious little hydroid polyp was found. At the time it was sketched, and a few notes made on the supposition that it was the larval form of some other hydroid, perhaps a Tubularian. In the following summer forms of the same kind with gonophores were found. This left no doubt that it was after all a mature form, but the limited number of specimens warranted no further conclusion than that the animal would probably prove interesting on account of its unattached condition, a character which would not have been remarkable in a larval form. Nothing like a perisarc was at first thought to be present, for, as was after-ward learned, there was simply a tubular secretion, only shreds of which remained on the captured polyps.
Laughter down-regulates negative emotional arousal amongst friends
Authors: Borrelli Mimi , sinha vikram , Scott Sophie 
Published: April 2021

Laughter is contagious, sensitive to social context, and can be used to mitigate negative emotional states. This experiment tested whether moments of transition from negative to positive affect were associated with more laughter if in familiar compared to unfamiliar company. 90 participants (47 females, mean age 20.61 years), either familiar (N=42) or unfamiliar (N=48) to the principle researcher, were randomly assigned to listen to 44 seconds of music which induced a fearful affect, positive affect or a neutral mood, followed by 30 seconds of infectious laughter (N=30/group). Filmed facial expressions were coded for four dependent variables (duration: half smile; full smile; laugh, and extent: peak mirth) of amusement in response to the laughter. Familiar participants fully smiled for longer than unfamiliar participants (F(1,84)=4.15, p=.045). There was an affect-familiarity interaction for peak mirth (F(2,84)=4.68, p=.01), time spent half smiling F(2,84)=5.00, p=.009), and fully smiling (F(2,84)=3.48, p=.035). Post hoc analyses revealed familiar participants exhibited greater peak mirth and smiled (half and full) for longer than unfamiliar participants in the fearful affect condition. Laughter and positive emotions may be used to moderate negative arousal more amongst people known to each other than amongst strangers.