bluuebunny/crossref_metadata_2025_split huggingface dataset:
Timing of events in overlapping cell reproductive sequences and their mutual interactions in the alga Scenedesmus quadricauda
Authors: Zachleder V. , ŠetlÍk I. 
Published: April 2021

ABSTRACT
Synchronous populations of the chlorococcal alga Scenedesmus quadricauda were subjected to various irradiances, photoperiods, heterotrophic growth and chloramphenicol treatment in order to induce different cell cycle patterns. The courses of cellular and nuclear division, and of commitments to them, were followed to measure duration of growth and reproductive steps and to analyze their mutual interactions in overlapped cell reproductive sequences. Duration of the growth steps (precommitment periods) was inversely proportional to the irradiance applied. It was prolonged if the growth was retarded by chloramphenicol. It is argued that light has an exclusively trophic function in regulating growth steps and can be replaced by glucose. The number of growth steps, and consequently the number of reproductive sequences, at a given irradiance can be experimentally changed by the photoperiod. The reproductive steps (postcommitment periods) are triggered by the termination of corresponding growth steps. They do not require any supply of external energy, and can therefore be terminated in darkness or in the presence of chloramphenicol. By varying the number of growth steps and their duration, a different extent of overlapping consecutive reproductive steps can be obtained. This overlapping is the major factor affecting the duration of reproductive steps which are proportional to the extent of overlapping. Complex interactions between growth conditions and overlapped reproductive steps resulted in substantial variations in the duration of the whole cell cycle. The present findings do not support the operation of a timing mechanism such as a pacemaker (Zeitgeber) or circadian rhythms, either in regulating the duration of the cell cycle or in the duration of reproductive steps.
Dermal cell populations show variable competence in epidermal cell support: stimulatory effects of hair papilla cells
Authors: Reynolds Amanda J. , Oliver Roy F. , Jahoda Colin A. B. 
Published: April 2021

ABSTRACT
A study was made of the comparative abilities of adult rat vibrissa dermal papilla cells, skin fibroblasts and 3T3 cells to support the initial attachment and subsequent growth and division of directly associated newborn rat skin basal epidermal cells. These associations were made under sub-optimal conditions; that is, in the absence of specific epidermal growth-promoting supplements, in order to assess more accurately the epidermal sustaining capacities of each dermal support Analysis of epidermal cell counts and close photographic scrutiny revealed that low-passage dermal papilla cells, closely followed by transformed dermal papilla cells, were conducive to the successful attachment and subsequent proliferation of epidermal cell populations under three different experimental protocols. In contrast skin fibroblasts did not support epidermal cell growth under any circumstances.
These findings are particularly interesting in that they constitute a rare in vitro example of epidermal cells that are not only supported, but also encouraged to proliferate, by an actively dividing adult skin-derived dermal cell population.
Membrane hyperpolarization activates trout sperm without an increase in intracellular pH
Authors: Boitano Scott , Omoto Charlotte K. 
Published: April 2021

ABSTRACT
Sperm from trout, like other sperm, are immotile in the seminal tract and initiate motility upon dilution into an appropriate fertilizing environment. Trout sperm motility is inhibited by high extracellular [K+] and can be activated by dilution of extracellular [K+]. Activation of trout sperm by the dilution of extracellular [K+] suggests regulation by membrane potential. Using the membrane potential-sensitive fluorescent dye 3,3’-dipropylthiocarbocyanine iodide (diS-C3-(5)) we directly measured the K+ contribution to the membrane potential. Manipulating the membrane potential with Cs+ and the ionophore valino-mycin can override K+ regulation. We show that trout sperm can also be activated in the presence of inhibitory [K+] by the addition of divalent cations. Activation by divalent cations is explained by the cations’ ability to mask membrane surface potential and thus alter the potential sensed by membrane voltage sensors. Using the surface potential-sensitive dye, l-anilino-8-naphthosulfonate (ANS), we directly measure the divalent cations’ ability to mask surface potential. We propose a model where membrane hyperpolarization is the trigger that initiates the cascade of events leading to trout sperm activation.
An increase in intracellular pH has been suggested to be a conserved step in the activation of sperm motility. We show that increasing intracellular pH by procedures that activate sea urchin and mammalian sperm does not activate trout sperm. In contrast, there is a decrease in intracellular pH upon activation of trout sperm motility. Artificially decreasing intracellular pH is not sufficient for activation of motility in trout sperm in an inhibitory [K+]. Thus, unlike some other sperm, changes in intracellular pH do not regulate trout sperm motility.
The fission yeast γ-tubulin is essential for mitosis and is localized at microtubule organizing centers
Authors: Horio Tetsuya , Uzawa Satoru , Jung M. Katherine , Oakley Berl R. , Tanaka Kenji , Yanagida Mitsuhiro 
Published: April 2021

ABSTRACT
γ-Tubulin exists in fission yeast as the product of an essential gene, encoding a 446 amino acid protein that is 77.3% identical to Aspergillus nidulans γ-tubulin. The gene disruption caused cell lethality, displaying condensed, undivided chromosomes with aberrant spindle structures. Anti-γ-tubulin staining showed that γ-tubulin is located, throughout the wild-type cell cycle, at the spindle pole bodies (SPBs), indicating that γ-tubulin associates with interphase SPB in the absence of microtubules. In addition, anti-γ-tubulin immunofluorescence staining revealed cytoplasmic, cell-equatorial putative MTOCs (microtubule organizing centers), which appear only during mitotic telophase and cytokinesis, and are located at the centers for the new cytoplasmic microtubule arrays of the two daughter cells. In the multiple-SPB mutant cutl-cdcll, anti-γ-tubulin antibodies revealed many dots on the periphery of the nucleus. These results confirm that γ-tubulin is an important member of the tubulin superfamily, suggest that it may be a universal component of MTOCs, and are consistent with a role for γ-tubulin in controlling microtubule formation in vivo.
On the Teeth on the Tongues of Mollusca
Authors: Ray J. E. G 
Published: April 2021

ABSTRACT
Lister, Leeuwenhoeck, Swammerdam, Poli, Cuvier, Fleming, Delle Chiaje, Verany, Eydoux, Souleyet, Van Beneden, Oersted, and some other naturalists, have, at various and distant periods, described and figured the teeth on the tongues of isolated species of Mollusca.
A few Remarks on a Paper, read before the Royal Society by Dr. J. W. Griffith, on the Angular Aperture of Object-Glasses
Authors: D’Alquen Dr. F. 
Published: April 2021

ABSTRACT
In the last number of the ‘Microscopical Journal’ an abstract of the above paper was given, and, if you think the subject of sufficient interest to your readers, I should feel obliged if the following observations could appear in your next number, in refutation of the only novel point in Dr. Griffith’s paper.
Geological society: On the Microscopical Structure of Freshwater Marls and Lime- stones
Authors: Sorby H. Clifton 
Published: April 2021

ABSTRACT
The author first described the general conclusions he had arrived at with respect to the condition of the mineral portion of calcareous organisms, which he considered is first deposited in the form of crystalline granules of variable size, that afterwards undergo more or less of crystalline coalescence. In some cases this scarcely occurs at all; but in others it does to a very considerable extent during the life of the organism, and this produces a great difference in the character of the particles into which it is resolved by decay. The falling to powder that then takes place is the result of the oxidization and removal of the organic portion, and, if no crystalline coalescence had occurred, the shell or other body might be resolved into the very minute, ultimate, crystalline granules ; whereas, if much coalescence had taken place, it would break up into much larger ones, showing in many instances its minute organic structure.
Hartig on the Phytozoa of Antheridia
Authors: Currey F. 
Published: April 2021

ABSTRACT
Was wird aus der Schwamfaden der Antheridien ? Dr. Hartig has devoted a section of his essay on the development of the vegetable cell, now in course of publication in the ‘Botanische Zeitung,’ to a consideration of the above question, and the results he has arrived at are highly curious and interesting. Should further investigation lead to a confirmation of Dr. Hartig’s views, the consequence will be that several genera of the Infusoria must be transferred to the vegetable kingdom. Dr. Cohn’s lately-published observations, will have already prepared the minds of the friends of the Infusoria for such a result, and will cause the blow aimed by Dr. Hartig at the animal nature of some of Professor Ehrenberg’s favourites to be less keenly felt. In the following pages we purpose giving the substance of Dr. Hartig’s paper, which is of great interest to microscopical observers ; the experiments are such as may be repeated without difficulty.
Further Observations on the Structure of Appendicularia Flabellum (Chamisso)
Authors: Huxley T. H. 
Published: April 2021

ABSTRACT
In a paper read before the Royal Society in 1851, I gave an account of a very singular animal which had been frequently observed and described under various names, as Appendicularia (Chamisso), Oikopleura (Mertens), Fritillaria (Quoy and Gaimard), Vexillaria (J. Müller), and Eurycercus (Busch), but whose precise place in the animal kingdom was still a matter of doubt. The essential points in that account will be found in the following extracts :—*
Further Observations on the Similarity of Forms observed between Snow Crystals and those of Camphor
Authors: Glaisher James 
Published: April 2021

ABSTRACT
The field of inquiry thus opened by Mr. Spencer has since engaged a portion of my attention. The following are some of the results of observation carried on at intervals, the solution being provided by Mr. Spencer, and a part, I believe, of that employed by him in his own experiments. The following are my notes on the subject.
Rudiments of Pathological Histology
Authors: Wedl Carl , Busk George 
Published: April 2021

ABSTRACT
The Sydenham Society has done unspeakable service for the medical profession by presenting its members with numerous works on Anatomy, Physiology, Medicine and Surgery, in an English form, which, but for it, would ever have remained in this country sealed books, unread and perhaps unknown to the vast majority.
On Dysteria; a new genus of Infusoria
Authors: Huxley Thomas H. 
Published: April 2021

ABSTRACT
The credit of the discovery of the animal which will be described in the following pages is due to my friend Mr. Dyster, of Tenby; and many of the most important statements regarding its structure and habits are based upon his observations. I think, therefore, I cannot do better than name the genus of which it wil form the type after him.*
On the presence of Silica in the Rubiaceæ and in Achillea Ptarmica
Authors: Leipner Adolph 
Published: April 2021

ABSTRACT
Amongst the various inorganic elements which we find present in plants, there is hardly one more interesting than silica, either to the amateur microscopist or to the truly scientific botanist. Some microscopic preparations of siliceous parts, obtained from the Equisetaceæ, Gramineæ, from the Deutzia scabra, and some other plants in which it has been discovered, are rarely wanting in the limited collection of the tyro, whom they please,—and never, I may say, in the cabinet of the experienced physiologist, whom they still, to some extent, puzzle.
Archives of medicine
Authors: Beale Lionel 
Published: April 2021

ABSTRACT
This is the first number of a new medical periodical, but how often it is to appear the editor does not inform us. The object of the editor is to publish papers of a more thoroughly scientific character than are usually found in medical periodical literature, and to have these papers freely illustrated. The subjects on which he wishes to receive papers are as follows: Practical clinical observations.Original researches in Physiology and Pathology.Chemical and Microscopical examination of the solids and fluids of the body.Descriptions of scientific processes.Condensed reports of researches published elsewhere.
Notice of the Occurrence of a Nematoid Parasite in the Ovum of Limax griseus
Authors: Barthélemy M. A. 
Published: April 2021

ABSTRACT
In studying the development of Limax griseus, I was not a little surprised to discover in the first ovum submitted to microscopic examination a minute Nematoid worm, in which might still be observed some vitelline granules. In other ova, more advanced in development, I have noticed similar vermicules, often to the number of three or four, and which had apparently undergone a development corresponding to that of the creature whose domicile they had invaded. At this stage they were large enough to be readily seen with a simple lens, performing tolerably active movements. In most cases they remain at some distance from the embryo, though occasionally I have noticed one of them attached to the vesicle which surmounts the head of the future mollusc. Lastly, in some ova still further advanced, the parasite had destroyed its host, the walls of the ovum were collapsed, and the Nematoid worms might be observed in the interior arrived at their full development—that is to say, furnished with the reproductive organs.
Tobacco and its adulterations with illustrations, drawn and etched
Authors: Prescott Henry P. 
Published: April 2021

ABSTRACT
Many substances used for the adulteration of articles of commerce, which formerly defied all kinds of investigation, are now easily discovered by the aid of the microscope. The medical man was the first to apply this instrument in the detection of fraudulent adulterations of food and medicine. The Government has been slow to appreciate its use in the cases where it might have been employed to detect fraud on taxed articles of consumption. We are, however, glad to be able to congratulate the Inland Revenue department on the possession of an officer who is so capable of appreciating the value of microscopic aid in the detection of adulterations as Mr. Prescott appears to be. It has been long known that chemistry is of little service in detecting the adulteration of tobacco. In fact, for many years, it seems, that instead of chemistry detecting frauds in the adulteration of tobacco, it was the unintentional source of fraud by the Government, who fined tobacconists for having tobacco in their possession which contained sugar, when it afterwards turned out that all tobacco naturally contains a certain quantity of sugar.
On the Structure and Mode of Formation of Starch Granules, according to the Principle of “Molecular Coalescence.”
Authors: Rainey George 
Published: April 2021

ABSTRACT
Starch, from its physiological importance, remarkable structural peculiarities, and general diffusion through the vegetable kingdom, has been a favourite subject of investigation with physiologists and microscopists. However, not-, withstanding the attention which has been devoted to its structure and development, it is acknowledged by the greatest physiologists to be known but little of. (See Mr. Busk’s paper on “Starch Granules,” in the number of the ‘Quarterly Journal of Microscopical Science’ for April, 1853.) There are, doubtless, intrinsic difficulties attending the investigation of this substance, but these have been very much augmented by the principle on which the examination has been conducted, namely, the cellular hypothesis. If this hypothesis had been in itself correct, and admissible as a basis of explanation of the facts connected with the structure and mode of formation of the starch granule, it ought, considering the amount of talent and ingenuity which have been employed in its application to these inquiries, to have thrown more light upon these much disputed, and as yet entirely unsettled questions.
Descriptions of Diatomaceæ, chiefly of those found in “Elide” (Lower California) Guano
Authors: Johnston Christopher 
Published: April 2021

ABSTRACT
I am fully aware of the fallacies which beset the diatomist who establishes new species from the inspection of rare, isolated, and prepared valves; but I am of opinion that science is made the gainer by his efforts, provided he is careful not to substitute names for things, and fancy for the sense. If the observer states the circumstances under which he obtained his facts, it is certainly pardonable in him to group these together in such a manner as to guide ethers in extending the limits of knowledge, whether ‘by verifying his specification, or by modifying it, when accumulated observations justify the emendation.
On the Distinguishing of Elevations and Depressions under the Microscope
Authors: Welcker H. 
Published: April 2021

ABSTRACT
It cannot be contested that the most important point in every microscopical investigation is the correct interpretation of the visible image presented to us. But, as in the latest classical work by Dr. Harting (‘Das Microskop,’ &c.) the subject of Microscopic Diagnosis does not appear to me to have been treated so fully or so correctly as it might have been, I venture to recur to the subject, which has already been noticed by me in papers on Microscopic Technology formerly published in this Journal. *
Atmospheric Micrography. Observations on the Corpuscles suspended in the Atmosphere
Authors: Pouchet M. 
Published: April 2021

ABSTRACT
(‘Comptes rendus/March 21st, 1859.)
The atmosphere contains, in suspension, numerous corpuscles, consisting of the detritus of the mineral crust of the earth, animal and vegetable particles, and the minutely divided débris of the various articles employed in our wants. These various kinds of corpuscles are more numerous and more voluminous in proportion to the degree in which the atmosphere is agitated by the wind; and they constitute what we term “dust.”
Observations on the Structure of Nerve-Fibre
Authors: Clark J. Lockhart 
Published: April 2021

ABSTRACT
Whenever we wish to ascertain the natural appearance and structure of the nerve-cells and nerve-fibres, these tissues should be examined in some transparent part during life, or on removal immediately after death, and with the addition only of a little serum of the blood. But when it is intended to investigate, in the nervous centres of the vertebrata, the mutual relation of these elementary parts, and their natural arrangement, such as the grouping of the cells and the course of the fibres, it becomes necessary to harden the nervesubstance in some kind of fluid, so that it may be cut into thin sections, which can then be rendered more transparent by a further process. The method which I extensively employ for such investigations is as follows:
On the frequent Occurrence of Vegetable Parasites in the Hard Tissues of the Lower Animals
Authors: Kölliker A. 
Published: April 2021

ABSTRACT
In examining the scales of Beryx omatus, Ag., from the chalk formation in England, I noticed peculiar tubular structures, presenting an elegant stelliform figure, of which I was at first at a loss what to make. Their similarity in form to pigment-cells led me at first to think they might be of that nature, but this idea was abandoned when I found that the structures in question occurred not merely in the external layers of the scales, but in the interior as well. At the same time I was unable to entertain any other supposition, since the structure exhibited no points of resemblance with any of the known forms of tubular and cellular structures of bones and scales.
New Experiments on Heterogenesis, by means of the Air contained in the Closed Cavities of Plants
Authors: Joly MM. N. , Mussey CH. 
Published: April 2021

ABSTRACT
At the beginning of the year, the authors communicated to the Academy the result of some experiments instituted with the view of satisfying themselves with respect to the origin of the Microphytes and Microzoa, which are always and everywhere produced in infusions of organic matters. After new experiments, continued uninterruptedly for six months, they are prepared with fresh evidence in the cause now at issue between the partisans and the opponents of heterogenesis.
On a New Species of Gregarina To be Called Gregarina Gigantea
Authors: Beneden Edouard Van 
Published: April 2021

ABSTRACT
The little organisms known as Gregarinæ have much attracted the attention of naturalists during late years. Their organisation is exceedingly simple; they consist of merely a single cell, but the history of their development, of their reproduction, and of their metamorphoses, has exercised the sagacity of a great number of eminent observers, and the profusion with which they are spread through nature has caused them to come under the notice of many naturalists. The literature relating to these inferior organisms is very rich, but, nevertheless, several points relating to their organisation and to their development are still completely unknown.
Bioplasm, and its Degradation; with Observations on the Origin of Contagious Disease
Authors: Beale Lionel S. 
Published: April 2021

ABSTRACT
Hitherto I have employed the simple term germinal or living matter, to denote that matter which takes part in the formation of all living beings and their tissues and organs -, but the term is lengthy, and in some respects perhaps awkward and inconvenient. It cannot be used alone when speaking of a single particle, nor can it be employed adjectively. The word “protoplasm” has been much used for some years past, but the vagueness attached to it renders it unfitted for employment here. I require a word to denote living, forming, growing, self-producing matter, as distinguished from matter in every other state or condition whatever. Now “protoplasm” has been applied, both in this country and in Germany, to lifeless matter as well as to living matter, to formed matter and tissue as well as to the formative matter. And more recently Prof. Huxley and others have added to the confusion by giving it a still wider signification—so very wide, indeed, that almost anything that ever formed part of an organism may, according to their view, be denominated protoplasm. Dead matter and living matter, and roast mutton, boiled as well as unboiled white of egg, and a number of other things, moist and dry, having structure and structureless, alive and dead, are said to be protoplasm, so that the word ceases to be distinctive of matter in any particular state. It becomes, in fact, useless.
On some Compounds derived from the Colouring Matter of Blood
Authors: Sorby H. C. 
Published: April 2021

ABSTRACT
Several months ago I determined to thoroughly investigate the colouring matter of blood, in order to be able to apply to the detection of blood-stains all the improved methods of experiment which I had devised since the publication of my first paper on that subject.1 I anticipated being able to finish this inquiry in time to publish an account of my observations in this number of the ‘Quarterly Journal of Microscopical Science,’ but so many unexpected phenomena presented themselves that I have not yet been able to clear up several important questions. However, not wishing to entirely postpone the subject for another three months, I will now give a short account of some of my conclusions.