bluuebunny/crossref_metadata_2025_split huggingface dataset:
BWTG3 hepatoma cells can acquire phenylalanine hydroxylase, cystathionine synthase and CPS-I without genetic manipulation, but activation of the silent OTC gene requires cell fusion with hepatocytes
Authors: Farmer A. A. , Goss S. J. 
Published: April 2021

ABSTRACT
The mouse hepatoma BWTG3 has been tested for its ability to grow in three different media that select for traits normally expressed in adult liven homocysteine medium to select for cystathionine synthase (CS), tyrosine-free medium for phenylalanine hydroxylase (PH), and ornithine medium for carbamylphosphate synthetase-I (CPS-I) and ornithine transcarbamylase (OTC). In no case were the cells immediately capable of bulk growth, showing that all these traits were in some degree deficient. However, the cultures in homocysteine medium and in tyrosine-free medium both gave rise, spontaneously, to growing clones with frequencies of approximately 10−3 and 10−B, respectively. The deficiencies of CS and PH were accordingly excluded from further study, in view of their inherent instability. In contrast, no colonies ever formed in ornithine medium. Though neither CPS-I nor OTC were detectable in stock BWTG3 cells, it was found that CPS-I was readily inducible by hormones. The deficiency of OTC, however, appeared to be totally stable, showing no reversion in response either to hormones or to azacytidine treatment. This deficiency was investigated by fusing the hepatoma to OTC+ liver cells prepared from normal or sparse-fur (spf) mice. Sparse-fur mice were used because their OTC is mutant and has a distinctive pH-dependence. OTC+hybrids were readily produced, without the need for any specific selection for OTC, and, in one case at least, with only minimal chromosome segregation. In all the OTC+ hybrids made with spf cells, there was clear reactivation of the wild-type, hepatoma-derived OTC gene. The properties of the OTC in these hybrids varied according to the dosage of genes contributed by the hepatoma and the spf liver cells. The most likely explanation of these results is that the hepatoma lacks some activator of OTC expression, and that this deficiency is corrected in the hybrids, presumably by activator supplied by the liver cells.
Mechanism of collagen phagocytosis by human gingival fibroblasts: importance of collagen structure in cell recognition and internalization
Authors: Knowles G. C. , McKeown M. , Sodek J. , McCulloch C. A. G. 
Published: April 2021

ABSTRACT
Phagocytosis of extracellular collagen by fibroblasts appears to be the principal pathway of collagen degradation in the physiological turnover of connective tissues. To study the mechanism of collagen phagocytosis, subconfluent gingival fibroblasts were serum-starved and incubated for up to 16 h with collagen-coated fluorescent latex beads. Internalization of beads was measured either by flow cytometry or by image analysis. Phagocytosis was blocked by inactivation of protein kinase C with staurosporin, and was also decreased significantly (32%) when cells were pre-incubated for 6h with cycloheximide. Phagocytosis of collagen-coated beads appeared to be receptor-mediated, since internalization was inhibited threefold by the cellattachment blocking peptide (GRGDSP). The process of internalization was influenced by the type of collagen and its molecular structure. Thus, internalization was decreased in the order: type I&gt;V&gt;III collagen, and internalization of type I collagen was reduced significantly by digestion with either bacterial (45%) or vertebrate (38%) collagenase. However, collagen denaturation, which facilitates binding to fibronectin, did not effect internalization. Although concanavalin A stimulated both phagocytosis (71 %) and collagenase synthesis, PM A and IL-1, which also increase collagenase expression, did not affect phagocytosis, indicating that phagocytosis of collagen-coated beads does not require collagenase. Moreover, analysis of tissue inhibitor of metalloproteinase expression revealed no difference between phagocytic and non-phagocytic cells. Collectively, these results demonstrate that collagen phagocytosis is regulated through protein kinase C and is also dependent upon cellular recognition and collagen structure, but not on the expression of collagenase.
Distinguishing the sites of pre-rRNA synthesis and accumulation in Ehrlich tumor cell nucleoli
Authors: Thiry Marc , Goessens Guy 
Published: April 2021

ABSTRACT
The precise location of transcribing rRNA genes within Ehrlich tumor cell nucleoli has been investigated using two approaches: high-resolution autoradiography of cells pulse-labelled with tritiated uridine, varying the exposure time, and in situ-in vitro transcription coupled with an immunogold labelling procedure.
When autoradiographic preparations are exposed for a short time, silver grains are found associated almost exclusively with interphasic cell nucleoli. Labelling of extranucleolar areas requires longer exposure. Within the nucleolus, the first sites to be revealed are in the dense fibrillar component. Prolonging exposure increases labelling over the dense fibrillar component, with label becoming more and more apparent over the fibrillar centers. Under these conditions, however, labelling does not extend into the granular component, and no background is observed.
Initiation of transcription on ultrathin cell sections occurs preferentially at the borders of condensed chromatin blocks and in their close vicinity. The condensed chromatin areas themselves remain unlabelled. Inside most nucleoli, gold-particle clusters are mainly detected in the fibrillar centers, especially at their periphery, whereas the dense fibrillar component and the granular component remain devoid of label.
These results, together with previous observations made on the same cell type, clearly indicate that the fibrillar centers are the sites of rRNA gene transcription in Ehrlich tumor cell nucleoli, while the dense fibrillar component is the site of pre-rRNA accumulation.
Lectures on histology, delivered at the Royal College of Surgeons of England in the Session 1851-52.
Authors: Quekett John 
Published: April 2021

ABSTRACT
In pursuance of the plan laid down in his first volume, Professor Quekett has in this work presented us with another instalment of the histology of organic beings. The subject here taken up is the structure of the skeleton of plants and invertebrate animals. Although we hope Mr. Quekettt may be encouraged to proceed with the publication of his lectures, we think he has very judiciously selected his present subject as supplying a want of the physiologist and the microscopic inquirer. The fact is, at the present day, there is little to be added to our knowledge of the histology of the human body, and what we really want to complete our knowledge of the structure of organized beings, is more extended researches upon the lower animals. Our knowledge of vegetable structure, also, is much more extensive than it is of the lower animals. To all inquirers, then, in the field of comparative histology, this volume of Mr. Quekett’s lectures will be found very acceptable. We cannot commend Mr. Quekett’s volume as a comprehensive treatise upon all that is known with regard to the hard parts of plants and invertebrate animals ; but, like that which renders all his other writings valuable, it bears the impress of original observation, and in all cases the reader may rely upon the accuracy of the author. Mr. Quekett nowhere commits himself to physiological inferences or speculations, leaving those who follow him to form their own opinions with regard to the functions and relations of the parts he describes.
On the Magnifying Power of Short Spaces illustrated by the Transmission of Light Through Minute Apertures
Authors: Gorham John 
Published: April 2021

ABSTRACT
Having described in the former papers the appearances observable when pencils of light from small circular apertures are partially intercepted by certain opaque or transparent objects of definite shape and size ; and having shown that whether shadows or illuminated spaces are thus used, they serve to exemplify the magnifying power of short intervals existing between the organ of vision and the object to be examined, inasmuch as they occupy some position in space, and have a certain form, qualities which pertain to them in common with all substances appreciable by the sense of sight, we proceed to notice the phenomena which result when exceedingly narrow linear apertures are substituted for those of a circular form. In conducting these investigations it was not unreasonable to suppose, à priori, that if the size, the quality, and the position of the object to be examined, the direction and the intensity of the light which was used, the sensitiveness and immediate response of the pupil of the eye to the minutest variation in the quantity of light impinging on the retina, and the refracting qualities of the transparent portion of the visual organ, were each and all taken into account, so that a nice and delicate adjustment of the eye to the light, and of the light as well as of the size of the objects to the eye could be insured, appearances perhaps beautiful, doubtless uncommon, and certainly interesting to the physiologist might be fairly anticipated. Such anticipations, have been so far realized as to present a strong inducement to prosecute the subject with a legitimate prospect of still greater success.
Notes and observations on the sap-circulation of plants
Authors: Wenham F. H. 
Published: April 2021

ABSTRACT
Since my communication in the last number of this Journal, “On the Circulation of the Sap in the Leaf-cells of the Anackaris Ahinastrum” I have continued some investigations on non-aquatic plants, with the view of ascertaining the relation or analogy, that the phenomena of their circulatory movements display, towards the subject of my former paper, and to each other respectively.
On a Universal Indicator for Microscopes
Authors: Bailey J. W. 
Published: April 2021

ABSTRACT
In the ‘Quarterly Journal of Microscopical Science,’ vol. i, p. 34, an ingenious contrivance for registering the position of microscopic objects is described by Mr. Tyrrel; a modification of this, by Mr. Aymot, is given in a subsequent number (1. c., vol. i. p. 301) ; and a still better arrangement for the same purpose, suggested by Mr. Brodie and applied by Mr. Okeden to his microscope, is described at p. 166 of volume iii. of the same work. The last mentioned device can scarcely be improved upon for convenience; but there is one defect which is inherent to all these inventions, viz., that they are essentially selfish contrivances, of no use to any one but the owner of the particular instrument to which they may be attached.
On the Reproductive Organs of certain Fungi, with some remarhs on Germination
Authors: Currey Frederick 
Published: April 2021

ABSTRACT
The following paper is intended as a sequel to a previous communication on the same subject which appeared in the last volume of this Journal (see vol. iii., p. 263.) The instances in which a particular fungus has been observed to produce a variety of fruits differing essentially from one another, are already very numerous, and are daily on the increase. This polymorphism of fructification is highly interesting and important, not only in a physiological point of view, but from the effect which it must necessarily have upon the classification of the vast tribe of Fungi. Not only have different genera of the same order been already proved to be identical, but Fungi originally classed in different orders, and apparently of widely-different habits and structures, have been proved to be the produce of the same mycelium. The facts which I proceed to mention, are principally the result of observations made since the publication of my former paper, and they will, I hope, be considered interesting additions to this branch of microscopical science.
Description of some New Diatomaceous Forms from the West Indies
Authors: Greville Robert Kaye 
Published: April 2021

ABSTRACT
Some months ago I received a box of shells from my friend Mrs. William Eccles, of Trinidad, among which was a small marine species covered with an entangled tuft of sea-weeds and zoophytes. This, as it appeared to contain Diatomaceæ, I manipulated in the usual way, and on careful examination found it to yield a number of exceedingly interesting kinds, especially if the very small quantity of the prepared material be considered. As it would scarcely serve any useful purpose to work out every form which presented itself in a gathering so trifling in extent, I propose to confine myself on the present occasion to the description of such as seem to be new; and I shall only mention that among the remaining forms worthy of notice the following were observed: Synedra undulata, Bail., S. superba, Kütz., Cocconeis Grevillii, Sm., Navicula Hennedyi, Sm., N. crabro, Eh.,*Amphora obtusa and A. lineata, Greg., Podocystis Americana, Bail., Climacosphenia moniligera, Eh., Rhabdonema arcuatum and R. Adriaticum, Kütz., Grammatophora hamulifera, Kütz., Asterolampra impar, Shadb.
The existence of Birds during the deposition of the Stonesfield Slate proved by a comparison of the Microscopic Structure of certain Bones of that formation with that of Recent Bones
Authors: Dennis J. B. P. 
Published: April 2021

ABSTRACT
From extensive observations made upon the bones of birds, I find that, in their microscopic characters, their bones are as distinct from those of mammifers as the latter are from the bones of saurians. As the lacuna in the saurian bone exceeds that of the mammal in the size of its canaliculi, so does the latter exceed that of the bird;* and as they are more numerous and more branched in the bird than in the mammal, so in like manner are they more so in mammalian than in saurian bone.
On the Zoological Position of Dysteria
Authors: Gosse P. H. 
Published: April 2021

ABSTRACT
During my stay at Tenby last summer, I had some opportunities of studying the new and singular animal Dysteria, the subject of Professor Huxley’s excellent memoir in the January number of the f Quarterly Journal? While I cannot but admire the skill with which he has worked out the interior structure, some parts of which presented to my own investigations insuperable difficulties; and while, in respect to most of the details which I did succeed in resolving, I agree with him; I had, before his memoir was published, formed a different judgment as to its zoological position.
A Synopsis of the British Diatomaceæ
Authors: Smith William 
Published: April 2021

ABSTRACT
Those microscopists who are working at the British Diatomaceæ will rejoice to know that the second volume of Professor Smith’s work is at last completed. They have now a complete work to which they may refer for information with regard to all forms of British Diatomaceæ. This second volume is a worthy companion of the first. The descriptions of the species are ample, the notes are valuable, and the plates, if possible, exceed the last in their beauty and accuracy. With regard to the latter, we are sure that Professor Smith would be amongst the first to acknowledge how greatly the value of his work is enhanced by the unrivalled skill with which Mr. Tuffen West has delineated the beautiful objects he has described.
On a New Species of Bugula
Authors: Alder Joshua 
Published: April 2021

ABSTRACT
Polyzoary orange-coloured or yellowish, paler when dry; one to two inches high, forming an ascending spiral, the branches dividing dichotomously, truncated at top, and arching outwards. Cells in two to five series, elongated, the aperture reaching nearly to the bottom; a single erect spine at each upper angle. Avicularia of two sizes, those on the outside moderately large, with a rounded head, and a short back abruptly bent at the point; situated on the upper part of the margin of the cell; inner avicularia small. Ovicapsules subglobose, with a rim rising into a peak in front.
Flustrella hispida and its development
Authors: Redfern Peter 
Published: April 2021

ABSTRACT
The Flustrella hispida of Dr. Gray is the Flustra hispida of Fleming, and the Flustra carnosa of Dalyell and Johnston. It seems to have been overlooked by Mr. Gosse, in his ‘ Marine Zoology,’ and to have attracted much less attention than it deserves, when its beauty and general distribution are considered.
On the form, Density, and Structure of the Crystalline Lens
Authors: Nunneley Thomas 
Published: April 2021

ABSTRACT
The Lens, as its name implies, is the most important portion of the dioptical ocular apparatus. It is at the same time the most perfect of its kind in the world. It has hitherto (and probably will continue so to do,) defied the efforts of human ingenuity to imitate. Hence, while its importance in health, the great changes which it undergoes in disease, and the skill and knowledge requisite for its treatment and removal, have always rendered it an object of great interest to the anatomist and surgeon—its perfect action in converging the rays of light to a focus upon the retina, so as practically, if not absolutely, to overcome the aberration of sphericity, has caused its form, structure, and density to be matters of the closest investigation and calculation by opticians and mathematicians. The difficulties of the inquiry have been at least equal to their importance, so that as much, if not more, controversy and difference of opinion have existed as to the structure of the crystalline lens, as of any part of the eye.
On some Conditions of the Cell-Wall in the Petals of Flowers, with Remarks on some so-called External Secondary Deposits
Authors: West Tuffen 
Published: April 2021

ABSTRACT
In working over microscopic subjects generally, my attention was arrested by that well-known object, the petal of the geranium, and the attempt to reconcile the appearances found with the descriptions in books led to investigations, some of the results of which are embodied in the following communication. How far these agree with the opinions entertained by previous observers will best appear in the course of my remarks.
Observations on the Development of some parts of the Skeleton of Fishes
Authors: Huxley Thomas H. 
Published: April 2021

ABSTRACT
The following observations were made principally upon the Stickleback (Gasterosteus leiurus) in the summer of the present year. Some of them were briefly alluded to in my Croonian lecture “On the Theory of the Vertebrate Skull,” delivered before the Royal Society on the 17th of June last, and will be more fully treated of hereafter; the rest have not yet been published.
On the Mode of Formation of Shells of Animals, of Bone, and of several other Structures, by a process of Molecular Coalescence, demonstrable in certain artificially formed products
Authors: Rainey George 
Published: April 2021

ABSTRACT
Most of our readers will recollect a paper read by Mr. Rainey before the Microscopical Society, and which appeared in the ‘Transactions,’ on the subject of this work. In that paper Mr. Rainey pointed out the remarkable fact that many of the appearances presented by the hard structures of animals, and which had been usually referred to cell-development, were really produced by the physical laws which govern the aggregation of certain salts when exposed to the action of vegetable and animal substances in a state of solution. The paper to which we allude succeeded one which he had previously published in the ‘British and Foreign Medico-Chirurgical Review,’ and the present work consists of the observations contained in these two papers, with much new matter, both physical and anatomical. We need not repeat or discuss here Mr. Rainey’s views, but we give an extract from his Preface :
Descriptions of New Species of Polyzoa
Authors: Barlee George 
Published: April 2021

ABSTRACT
The assiduous dredging labours of Mr. Barlee, more especially in the Northern, seas of Scotland, have, as is well known, been the means of introducing numerous additions to the British Marine Fauna, among which, those belonging to the domain of Zoophytology are by no means the least considerable. Having been favoured by Mr. Barlee with the opportunity of examining the Polyzoa collected by him within the last two years, we here commence the description of the new or imperfectly known species comprised among them. As these are numerous, and our limits, so far as illustrations are concerned, circumscribed, the description of these species will occupy several numbers of the journal, although, in the meanwhile, brief descriptions of most of the new forms were presented to the British Association at its late meeting.
Pancreas
Authors: Turner Wm. 
Published: April 2021

ABSTRACT
The investigation of the relations of the minute gland ducts to the ultimate gland follicles in the human pancreas presents considerable difficulties. This is owing, partly, to the great delicacy and transparency of the structures, and partly, because from the close manner in which the minute lobules of the gland are crowded together, it is difficult to obtain a satisfactory view of a single isolated lobule. Thus, the mode of connection of the fine excretory duct of the lobule with the sacculated gland follicles at its extremity cannot clearly be estimated. Moreover, if it is attempted to separate the lobules from each other by tearing them asunder with needles, the relations of the parts become so disturbed, that the examination does not afford any very decided results. For these reasons, it has been customary, in describing the minute structure of this gland, to refer especially to the appearance which it presents in the smaller and more common Rodents, such as the Rat or Mouse.
On the Mature Condition of Trichina Spiralis
Authors: Leuckart Rudolph 
Published: April 2021

ABSTRACT
Some months since I communicated to my friend, Professor Van Beneden, at Louvain, the results of a helminthological experiment, which appeared to establish the connexion of Trichina with Trichocephalus, already supposed to exist by Meissner, Küchenmeister, and others. In this experiment, I fed a young pig with a quantity of trichinised flesh, for which I had been indebted to the kindness of Professor Nasse of Marburg; and on dissection, after the lapse of four weeks, I discovered in the large intestine a very considerable number of Trichocephalus dispar, probably thirty or forty specimens, some of which were in a state of perfect sexual maturity, and some nearly in that condition.
Atmospheric Micrography. On the Means by which all the Corpuscles Normally Invisible, contained in a Determinate Volume of AIR., may be collected into an infinitely Small Space
Authors: Pouchet M. 
Published: April 2021

ABSTRACT
I have succeeded, by means of a very simple instrument, in concentrating, upon an infinitely minute surface, all the solid and normally invisible corpuscles floating in the atmosphere, so as to allow of their being strictly appreciated and counted. By this means we can, if we please, concentrate on a glass, and within a space of two square millimetres, all the particles disseminated in a cubic mètre of the atmosphere, or even more.