bluuebunny/crossref_metadata_2025_split huggingface dataset:
Telophase disc: a new mammalian mitotic organelle that bisects telophase cells with a possible function in cytokinesis
Authors: Andreassen Paul R. , Palmer Douglas K. , Wener Mark H. , Margolis Robert L. 
Published: April 2021

ABSTRACT
We have discovered a novel mitosis-specific human autoantigen that arises at the centromeres of prophase chromosomes, but ultimately participates in formation of an organelle that bisects the cell at late anaphase and during telophase. The organelle, discernible as a three-dimensional disc by confocal microscopy, encompasses the entire midzone diameter, and its distribution survives disassembly of interpolar microtubules by cold temperature treatment and detergent lysis of cells. Cytokinetic furrow contraction proceeds normally in dihydrocytochalasin B (DCB)-treated cells, and antigen distribution in the furrow is unaltered. In DCB, the furrow retracts in early interphase, coincident with loss of normal membrane association with the disc, resulting in the formation of binucleate cells. The midzone disc in both drug-treated and normal cells is present at the correct time and position to play a central role in cytokinesis. By immunocytochemistry, the disc appears to contain myosin but not actin. The position of the disc and the possible presence of myosin suggest that cytokinesis may involve the interaction of the disc organelle with actin in the cell cortex to produce cleavage in mammalian cells.
The drug probenecid inhibits the vacuolar accumulation of fluorescent anions in onion epidermal cells
Authors: Oparka K. J. , Murant E. A. , Wright K. M. , Prior D. A. M. , Harris N. 
Published: April 2021

ABSTRACT
The drug probenecid has been shown to inhibit the vacuolar accumulation of a range of fluorescent anions with differing pK2 values (Lucifer Yellow CH, Cascade Blue hydrazide, sulphorhodamine G, car-boxyfluorescein, FITC) in onion epidermal cells. In the absence of the drug, uptake occurred into the vacuole and was sensitive to extracellular pH. In the presence of the drug, the dyes accumulated exclusively in the cytoplasm and nucleus. Probenecid also induced vésiculation of the tonoplast and caused the cytoplasm to become polar, both of these structural changes being reversible by removal of the drug. In the case of the permeant FITC molecule, probenecid inhibited net uptake into the epidermal cells, and addition of the drug to cells that had already accumulated dye in the central vacuole resulted in rapid dye leakage across the tonoplast. However, the other more impermeant probes failed to leak to the cytoplasm once they had accumulated in the vacuole, even after prolonged exposures to probenecid. The data are discussed in the light of recent evidence for probenecid-sensitive carriers capable of transporting fluorescent anions across the endosomal membrane of macrophages and in relation to the concept of a detoxification system for the sequestration of xenobiotic anions by plant cells.
Cytokeratins are exposed on the outer surface of established human mammary carcinoma cells
Authors: Godfroid Edmond , Geuskens Maurice , Dupressoir Thierry , Parent Isabelle , Szpirer Claude 
Published: April 2021

ABSTRACT
Normal human mammary epithelial cells and established tumour cells of the same origin express three to eight cytokeratins, which are distributed throughout the cytoplasm in the form of intermediate filaments. The combined use of the iodogen and the two-dimensional gel electrophoresis methods has allowed us to demonstrate the presence of cytokeratins 8, 18 and 19 on the outer surface of established human mammary carcinoma cells, in particular MCF-7 cells, while they were absent from the surface of normal mammary cells in primary culture. By ultrastructural immunocytochemistry, these cytokeratins were localized on blebs formed by the cell surface. Cytokeratins 8,18 and 19 were also detected in the culture medium of mammary carcinoma cells.
Possible roles for TGFβ1 in the gastrulating chick embryo
Authors: Sanders E. J. , Prasad S. 
Published: April 2021

ABSTRACT
We have examined the immunocytochemical distribution of TGFβ1 (transforming growth factor β1) in the gastrulating chick embryo, and have correlated the results with the ability of this factor to promote in vitro changes in the phenotype of mesoderm and epiblast cells. The findings, together with the demonstration that exogenous TGFβ1 is also able to modulate extracellular matrix deposition by these cells in culture, are consistent with a role for this factor in the formation and morphogenesis of the early mesoderm.
Immunofluorescence analysis, using an antibody to the amino-terminal fragment of TGFβ1, indicates that this factor is located in, or between, cells of the medial epiblast, Hensen’s node and primitive streak. At Hensen’s node, cells of the hypoblast were also strongly labelled. Ingressed mesoderm cells, lateral to the streak, show considerably stronger and more diffuse labelling than the overlying epiblast cells. Although the fluorescent labelling appears to be associated with the extracellular matrix surrounding the mesoderm cells, it is not bound to hyaluronic acid, which is the preponderant molecule in the matrix at this time in development. When added exogenously to cultures of mesoderm cells growing with epithelial characteristics on fibronectin, TGFβ1 effects an epithelial-mesenchymal transformation within 24 h. The reverse transformation is effected in mesoderm cells grown on laminin, while the epiblast cell phenotype is not affected by this treatment regardless of the substratum. TGFβ1 is also able to down-regulate the deposition of fibronectin by mesoderm cells grown on fibronectin and of epiblast cells grown on laminin, but up-regulate fibronectin deposition by mesoderm on laminin. Similar substratum-dependent changes are seen in laminin deposition, which is down-regulated in mesoderm on laminin and up-regulated in epiblast on laminin. No effect on laminin deposition is seen in either cell type grown on fibronectin. Expression of the fibronectin receptor is also down-regulated by TGFβ1 in mesoderm cells grown on fibronectin, and this may explain the decreased deposition of fibronectin associated with these cells under these conditions. We suggest that these results are consistent with a reinforcing role for TGFβ1 in the transformation that results in the emergence of mesoderm cells at gastrulation. This factor may also be involved in the maintenance of the fibroblastic phenotype of the mesoderm cells after their ingression, by effects on the expression of receptors for extracellular matrix and on the deposition of matrix by these cells during their early morphogenesis.
Smooth muscle α-actin is a marker for hair follicle dermis in vivo and in vitro
Authors: Jahoda Colin A. B. , Reynolds Amanda J. , Chaponnier Christine , Forester James C. , Gabbiani Giulio 
Published: April 2021

ABSTRACT
We have examined the expression of smooth muscle α-actin in hair follicles in situ, and in hair follicle dermal cells in culture by means of immunohistochemistry. Smooth muscle "-actin was present in the dermal sheath component of rat vibrissa, rat pelage and human follicles. Dermal papilla cells within all types of follicles did not express the antigen. However, in culture a large percentage of both hair dermal papilla and dermal sheath cells were stained by this antibody. The same cells were negative when tested with an antibody to desmin. Overall, explant-derived skin fibroblasts had relatively low numbers of positively marked cells, but those from skin regions of high hair-follicle density displayed more smooth muscle α-actin expression than fibroblasts from areas with fewer follicles. 2-D SDS-PAGE confirmed that, unlike fibroblasts, cultured papillacells contained significant quantities of the α-actin isoform.
The rapid switching on of smooth muscle α-actin expression by dermal papilla cells in early culture, contrasts with the behaviour of smooth muscle cells in vitro, and has implications for control of expression of the antigen in normal adult systems. The very high percentage of positively marked cultured papilla and sheath cells also provides a novel marker of cells from follicle dermis, and reinforces the idea that they represent a specialized cell population, contributing to the heterogeneity of fibroblast cell types in the skin dermis, and possibly acting as a source of myofibroblasts during wound healing.
Conserved structural motifs in cyclins identified by sequence analysis
Authors: Nugent Jonathan H. A. , Alfa Caroline E. , Young Tania , Hyams Jeremy S. 
Published: April 2021

ABSTRACT
Cyclins, as regulatory subunits of the ubiquitous p34cdc2 protein kinase, act as key controlling elements of the eukaryotic cell cycle. We have examined published sequences of A- and B-type cyclins for both amino acid and secondary structure homologies. In particular, we sought regions of homology outside the recognised area of sequence conservation known as the ‘cyclin box’, as well as conserved features predicted to lie at the protein surface. Our analysis demonstrates the existence of a number of islands of homology outside the cyclin box, and indicates candidate residues for phosphorylation.
One of these, a motif containing the amino acids SPXXXE/D is also present in fission yeast pl38UC1, another protein known to interact with p34ccfc2. This motif may define a possible p34cdc2 binding or phosphorylation site. A database search revealed that the CDC25 and SCD25 genes of the budding yeast Saccharomyces cerevisiae also contain some of the newly identified motifs, perhaps indicating a common regulatory or degradation pathway.
Handbuch der Gewebe-uehre des mensches für aebzte und studihende, mit 313 holzschnitten
Authors: Kölliker Von A. 
Published: April 2021

ABSTRACT
“ Medicine has arrived at such a stage that Microscopical Anatomy appears to form its foundation, as much as the anatomy of the organs and systems; and a thorough study of Physiology and Pathological Anatomy is impossible without an exact knowledge of the most minute formal elements. It becomes then the duty of those who cultivate this field of science not only to communicate their observations to their fellow-workers and to those who are more profoundly acquainted with medicine, but to enable all those who are concerned with the study of Man, and especially studentsand practitioners, to profit thereby. The present work seeks to perform this task by giving as condensed as possible a view of the relations of the elementary parts of the body and of the more minute structure of the organs; avoiding all polemical discussions, with the exception of a few of the more important points as yet sub judice, and leaving the history of the science completely in the background; but, on the other hand, entering as fully as possible into those points which bear upon Physiology, Pathological Anatomy, and Comparative Histology.”
On certain Appearances occurring in Dentine, dependent on its Mode of Calcification
Authors: James S. , Salter A. 
Published: April 2021

ABSTRACT
In Kölliker and Siebold’s Zeitschrift for 1850, Czermak published a paper, on some points of the minute anatomy of the teeth, whose importance has not, as it seems to me, been sufficiently appreciated in this country. No abstract or translation of this paper has yet appeared in English, though the interest and value of its contents probably equals any single other that has appeared since the earlier writings of Purkinje and Retzius.
Translations: Remarks on the Structure and function of the Retina
Authors: Müller H. 
Published: April 2021

ABSTRACT
The view respecting the physiological function of the various layers of the retina arrived at by Professor Kölliker, from the investigation of the human eye, and which he has detailed in a previous paper in these Transactions, I have, also, been led to adopt in the most essential points, from continued researches respecting that membrane.
On the construction and use of the microscope
Authors: Hannover Adolphe , Goodsib John 
Published: April 2021

ABSTRACT
Dr. Hannover’s book is short, which is a great recommendation, and it contains many judicious and useful observations, and is evidently the production of an experienced microscopist ; but we really can scarcely find in it much that should entitle it to appear in an English dress, as it is quite evident that the author is totally unacquainted with the present state of the microscope in this country, however familiar he may be with those of foreign construction. He does not mention, and appears to be unacquainted with any English microscope maker except Mr. Pritchard. Were he aware of what they have done, and still are daily doing, towards the perfection of the microscope as an instrument of scientific research, Dr. Hannover would surely have referred to the labours of Ross, Powell, and of Smith and Beck ; men who, with the aid of Mr. Lister, have done more in the improvement of the achromatic microscope than all the continental opticians together, and whose instruments, both for optical perfection and mechanical contrivances are, as we believe, unrivalled by those of any country in the world. But we are indeed surprised that his learned English editor should have been content thus to ignore the merits of his countrymen, and to omit all notice of some of the most important improvements in the microscope and its appliances, which have now been long in daily use. Many other proofs of Dr. Hannover’s want of information on the points to which we have referred might be adduced, but we would merely, in justification of what we have said, remark, that he appears to be quite ignorant that object-glasses may be made to adjust to varying thicknesses of the glass employed to cover an object (pp. 25, 59), although the mode in which this adjustment might be made was described by Mr. Ross as long ago as 1837, and has been universally adopted by English opticians since that time. He makes no mention either of any of the more recent, ingenious, and most valuable modes of illumination, to which, for some time past, so much and such successful attention has been paid. We refer more particularly to such contrivances as Gillett’s condenser, and the parabolic reflectors of Wenham and Shadbolt.
On a Substance Presenting the Chemical Reaction of Cellulose, Found in the Brain and Spinal Cord of Man
Authors: Virchow Rudolph 
Published: April 2021

ABSTRACT
It is well known that Carl Schmidt *was the first to discover in the Ascidians the presence of a principle previously known to exist only in plants, viz. cellulose, and to show that it was a constituent of the animal tissue. The researches of Kölliker and Löwig, † of Schacht, ‡ and of Huxley, § have established this important fact. The occurrence of this substance, however, was limited to a comparatively very low class of the Invertebrata, and the further discovery made by Gottlieb, in Euglena viridis, viz. that this infusorium contains paramylon, a body isomerous with starch, also had reference only to a creature in the lowest class of the animal kingdom. || Nothing of the kind, on the other hand, has been known as existing in the vertebrata, and it is only since the discovery by C. Bernard—that the liver produces sugar—that we have had reason to suppose that substances belonging to the amylum series may also have a representative.
On the Structure and Vital Properties of the Contractile Substance of the Lowest Animals
Authors: Ecker Alex 
Published: April 2021

ABSTRACT
These observations relate principally to the nature of the substance of which the body of the Hydra viridis is composed, but the conclusions are applied also to many other of the lower animal forms. It is stated that the entire body of the Polype consists of a homogeneous, sometimes clear, sometimes granular, soft, extensible, elastic, and contractile substance, which is reticulated with clear spaces, containing a more or less clear fluid. Ecker denies that cellular structure is found in any part of the animal, of which structure Corda and Baumgartner would make it entirely to consist. The three layers which are presented in the body and arms of the Hydra, are in immediate connexion, and are distinguished : 1. The external— by the presence in it of the thread-cells and the greater rarefaction of the tissue. 2. The middle—by the green granules and a less broken-up tissue: and 3. The innermost layer— by the brown excretion-granules, and during digestion by various absorbed matters, oil-drops, &c. From this similarity in the structure of the three layers, it is probable they are all equally contractile ; though it is perhaps the middle layer in which this property resides in greatest activity.
Beitrage Zur Mykologie (Contributions to Mycology)
Authors: Fresenius Dr. George 
Published: April 2021

ABSTRACT
Dr. Fresenius commences his work with an expression of regret that Mycology has up to the present time been so little studied; and attributes the neglect partly to the unsightliness (unscheinbarkeit) of the objects of the study. We think, however, that the charge of unsightliness is one which cannot be maintained against fungi in general. The Agaricus muscarius, with its brilliant crimson pileus and snowy gills, the Agaricus rutilans with a cap of more sober crimson and gills of the richest yellow, the Agaricas psittacinus, or Parroquet Agaric, varied as the plumage of the bird after which it is named ;—these, and many others which might be mentioned, fairly rival flowers in beauty. In fact, a well-arranged group of Agarics, Clavarias, &c., gathered from the first wood into which the botanist may wander, would form as pretty a decoration for a lady’s boudoir as any bouquet from the greenhouse. Those persons therefore who, without troubling themselves with scientific details and distinctions, look only to the external charms of the productions of nature, would find ample employment in searching out the beauties of the Fungi. We find them assuming the forms of clubs, mitres, bowls, cups, stars, and even of birds’-nests, and lanterns;* and their colour is as varied as their shapes, and growing as they principally do, upon the mouldering remains of other organisms, they seem intended, as Mr. Lee has happily expressed it, to deck even decay and ruin with beauty.
Some observations on the Illumination of transparent objects
Authors: Rainey George 
Published: April 2021

ABSTRACT
I may observe, that I was rather surprised to see these images on globules of mercury even as large as 1-70th of an inch in diameter, especially as they occupied a part of the globule exactly opposite to that on which the light coming directly from the condenser fell. The illumination of this part of a globule cannot be attributed to radiated light, as none of the rays coining from below can reach it, and a mere image on a reflecting surface cannot be supposed capable of absorbing light, and therefore it cannot radiate it.
On the Manufacture of Large Available Crystals of Sulphate of Iodo-Quinine (Herapathite), for Optical Purposes as Artificial Tourmalines
Authors: Herapath William Bird 
Published: April 2021

ABSTRACT
Having been repeatedly applied to by various parties for the details of my process for the manufacture of these useful crystals, I have been induced to enter into numerous experiments to obtain greater certainty in the results, and to study the conditions necessary for the production of broad foliaceous plates. Permit me to make the formula known to science, together with the precautions necessary for adoption to secure the crystals when obtained, and to mount them so as to be available as polarisers or analysers for the microscope, or even to enable us to perform all the experiments in the polariscope.
Notice of the New Forms and Varieties of Known Forms Occurring in the Diatomaceous Earth of Mull; With Remarks on the Classification of the Diatomaceæ
Authors: Gregory William 
Published: April 2021

ABSTRACT
The two notices which have already appeared in the Journal have made known the occurrences, in this deposit, of about ninety distinct forms, of which two were noted as being new to science. But the continued and diligent examination of it, which I have carried on during my residence abroad last summer, has led to results so much more remarkable, that I have to beg of the readers of the ‘ Journal ‘ to regard those papers as merely introductory to a more satisfactory and complete account of this interesting deposit. This I shall now attempt to give; but the limits of this paper, and of the illustrative plate, will not allow me to complete it at this time, and a large portion of my materials must therefore be reserved for a subsequent number of the ‘ Journal.’
Remarks on the involution theory of the starch granule, and on the probable structure of this body
Authors: Allman Geo James 
Published: April 2021

ABSTRACT
It is now about twenty years since Fritzsche published the results of a series of careful and elaborate observations on the structure of the starch granule, † Fritzsche examined starch obtained from the potato and from several other plants, and concluded that the granule was composed of a series of layers of entirely similar composition, surrounding a minute central body or “nucleus,” whose behaviour under certain circumstances rendered it probable that it differed chemically from the surrounding layers : he maintained that in the formation of the starch granule these layers are deposited one over the other from within outwards, and that the peculiar concentric striæ visible in the granule indicate the surfaces of contact of the layers.
On the Propagation of the oscillariæ
Authors: Itzigsohn Hermann 
Published: April 2021

ABSTRACT
The definite form of the Oscillariœ, and the processes attending their growth, as regards outward appearances, are well known : their tænia-like, jointed structure ; their contents composed of phycochrom ; their motility; the frequently fringed points of the filaments ; the continual subdivision into two of their joints ; their rapid growth ; their spreading, &c. Premising that all this is known, I shall consider this definite form as the starting-point of their developmental processes, and proceed to indicate the relations of the other forms to it.
On the Magnifying Power of Short Spaces, illustrated by the transmission of Light through minute Apertures
Authors: Gorham John 
Published: April 2021

ABSTRACT
In the present communication it is my intention to furnish a few phenomena, illustrative of visual angle, of the magnifying power of short spaces intervening between the eye and the object, and of the inversion and multiplication of images by the simple transmission of light, without refraction, through small apertures in plane surfaces. As these illustrations are somewhat novel, I hope they may prove interesting to the readers of the Microscopic Journal’