bluuebunny/crossref_metadata_2025 huggingface dataset:
Phosphatidate phosphohydrolase activity as a marker for surfactant synthesis in organotypic cultures of type ii alveolar pneumonocytes
Authors: Douglas William H. J. , Sommers-Smith Sally K. , Johnston John M.
Published: April 2021

The specific activity of phosphatidate phosphohydrolase (PAPase) (EC 3.1.3.4) has been assayed in organotypic cultures of foetal rat lung type II alveolar pneumonocytes and in L2 cells derived from type II cells of the adult rat lung.

This enzyme catalyses a critical step in the synthesis of phosphatidylcholine, the major lipid component of pulmonary surfactant. Surfactant is produced by the mature type II cell in culture as well as in vivo. The specific activity of PAPase in organotypic cultures prepared from foetal rat lung starting at 16 days of gestation increased four-to fivefold during the first 7 days in culture. The specific activity of this enzyme was further increased through the 21 days of culture. In parallel with the increase in PAPase specific activity in the cultures were morphological changes in the type II cells such as the appearance of increased numbers of lamellar bodies. The specific activities of PAPase samples derived from non-type II cell cultures maintained under identical conditions were compared. Organotypic cultures and L2 cells, a culture system that also exhibits type II cell characteristics, show PAPase specific activities five to six times greater than cultures that do not contain type 11 cells. PAPase activity in the type 11 cell cultures parallels the development of mature patterns of pulmonary surfactant synthesis storage and secretion.
Particle arrays on insect nerve membranes
Authors: Flower N. E. , Briers J. D.
Published: April 2021

Freeze-fracture studies of Lepidopteran antennae have revealed the presence of orthogonal arrays of particles on antennal nerve membranes. Initial impressions were that several different arrays were present. Optical diffraction was used to examine the arrays on the electron micrograph negatives. This technique showed that all the arrays were derived from the same basic structure, suggesting that the superficial differences in appearance were due to shadowing effects. The particles are arranged in a lattice with spacings of 10’7 nm × 9·l nm. The arrays are not clear-cut but tend to break up, producing a disorganized region around their edges. The particles are shown to have depressions in them. However, the evidence available suggests that the arrays do not have the other characteristics of gap junctions. The arrays appear not to be present on most of the nerve membrane faces, occurring only in localized regions of the nerve membranes where they are present in large numbers. This suggests that the arrays may have a specialized local function.
Effects of endotoxin treatment on the differentiation of guinea pig megakaryocytes to blood platelets
Authors: Raha S. , Wesemann W.
Published: April 2021

The effect of endotoxin treatment (30μg/kg body weight) on megakaryocyte development and platelet production in guinea pigs was investigated. A moderate thrombocytopenia was noted at 24 h after endotoxin administration. Recovery was observed at 48 h when the platelet count had almost reached the normal level. A significant increase in platelet production was obtained at 48h, indicated by an enhancement in incorporation of labelled sulphate into platelets and also by an increase in the number of circulating heavier platelets. Megakaryocytes were classified into different developmental stages -megakaryoblast, promegakaryocyte, megakaryocyte -using standard morphological criteria (size, shape of nucleus, nucleus/cytoplasm ratio). The number of mature megakaryocytes increased at 24 and 48h after endotoxin treatment. It was possible to distinguish between two different types of mature megakaryocytes— early mature and mature megakaryocytes -by the presence of a methanol-sensitive acid phosphatase. This enzyme is found mainly in mature, presumably platelet-forming, megakaryocytes and in platelets. The increased number of mature megakaryocytes at 24 h was due to an enhancement in the number of early mature megakaryocytes, whereas the change at 48 h was due largely to an increased number of mature, platelet-forming megakaryocytes. Megakaryocytes were isolated from bone marrow of guinea pigs by Percoll densitygradient centrifugation and incubated with radioactively labelled leucine. Compared with the untreated controls megakaryocytes isolated 24 h after endotoxin treatment took up and incorporated higher amounts of leucine into protein, indicating a higher metabolic capacity of the early mature megakaryocytes. No alteration in the ploidy distribution of megakaryocytes was noted after endotoxin treatment.
Vanadate, an inhibitor of growth, development and endocytosis in Dictyostelium discoideum amoebae
Authors: Klein Gérard , Cotter David A. , Martin Jean-Baptiste , Satre Michel
Published: April 2021

Axenic growth of amoebae of the slime mold Dictyostelium discoideum was found to be reversibly inhibited by vanadate. Pinocytosis, when measured with fluorescein-labeled dextran as a fluorescent fluid-phase marker was strongly inhibited by vanadate. Inhibition was observable at vanadate concentrations as low as 0·2 mM. Sucrose entry through pinocytosis induced massive cell vacuolation and this effect was blocked by vanadate. Secretion of soluble lysosomal enzymes is another aspect of membrane traffic in Dictyostelium. Secretion of two typical lysosomal enzymes, acid phosphatase and hexosaminidase, was inhibited by concentrations of vanadate in the same range as for pinocytosis inhibition. Vanadate also prevented the morphogenetic developmental program that follows nutrient starvation. In contrast, vanadate did not prevent heat-induced spore germination. Vanadate had no significant action on the intracellular nucleoside triphosphate level or on the cytosolic pH. It is suggested that the particular effect of vanadate in Dictyostelium is to inhibit the fusion of endosomes with lysosomes. Our results provide a probe that could be useful to clarify the mechanisms of endocytosis.
Induction of dna synthesis by cholera toxin in the temperature-sensitive cell-cycle mutants of rat 3Y1 fibroblasts at a restrictive temperature
Authors: Kabemura Mayumi , Shimura Hideo , Matsuzaki Akinobu , Ohtsu Masumi , Kimura Genki
Published: April 2021

Four temperature-sensitive mutants of rat 3Y1 fibroblasts representing separate complementation groups (3YltsD123, 3YltsF121, 3YltsG125 and 3YltsH203) are arrested at a restrictive temperature of 39-8°C mainly with a G1-phase DNA content (temperature arrest). Cholera toxin (CT) (3μgml−1) induced DNA synthesis at 39·8°C in the temperature-arrested cultures of two mutants (3YltsD123 and 3YltsG125). This effect of CT was not mimicked by other agents known to elevate the cellular level of cyclic AMP, such as dibutyrylcyclic AMP, prostaglandin El and forskolin, suggesting that the elevation of cellular cyclic AMP level per se is not responsible for the induction of DNA synthesis by CT. Addition of the B subunit of CT to the temperature-arrested cultures of 3YltsD123 and 3YltsG125 did not induce DNA synthesis at 39·8°C, indicating that the binding of CT to the cell surface alone is insufficient for the induction. The CT-treated cell membrane fraction prepared from temperature-arrested 3YltsG125 cells had similar activity for [32P]ADP-ribosylation of the 45 ×103Mr protein to that prepared from cells proliferating at a permissive temperature of 33·8°C. All these results suggest that 3YltsG125 cells utilize a CT-responsive signal transduction pathway, different from adenylate cyclase cascade, for preparation for entry into S phase in the temperature-arrested 3YltsG125. A pertussis toxin-sensitive substrate seems to be involved in the pathway, because pertussis toxin suppressed the induction of DNA synthesis by CT at 39-8°C in 3YltsG125. Neither H-7 (inhibitor of protein kinase C) nor W-7 (inhibitor of calmodulin) influenced the DNA synthesis induced at 39·8°C by CT in 3YltsG125, suggesting that the pathways involving protein kinase C or calmodulin are not responsible for the process.
A mycoplasmal protein influences tumour cell invasiveness and contact inhibition in vitro
Authors: Schmidhauser Christian , Dudler Robert , Schmidt Thomas , Parish Roger W.
Published: April 2021

Fab fragments of a monoclonal antibody directed against p37, a protein associated with the surface of FS9 mouse sarcoma cells, were previously found to inhibit the highly invasive behaviour of FS9 cells in vitro. We show that p37 originates from Mycoplasma hyorhinis. Infecting various cell lines with the mycoplasma consistently increased their invasiveness when confronted with chicken heart fibroblasts using Abercrombie’s confronted explant technique. Conversely, removing the mycoplasmas or blocking p37 with specific Fab fragments reduced invasiveness. Analysis of individual cell collisions using time-lapse filming showed that the addition of Fab fragments to cells infected with M. hyorhinis greatly increased the level of contact inhibition. The antibody also reduced the invasiveness of transformed cells that did not express the p37 antigen. Hence, a cellular protein or proteins that are structurally related to p37 apparently influence invasive behaviour.
Adipocytic cells cultured from marrow have osteogenic potential
Authors: Bennett J. H. , Joyner C. J. , Triffitt J. T. , Owen M. E.
Published: April 2021

Stromal colonies with fibroblastic morphology grow from rabbit marrow cells in culture supplemented with foetal calf serum. In this study the same marrow cells cultured with autologous rabbit plasma and hydrocortisone form colonies of a single lineage that express the adipocytic phenotype. A comparison of the potential for differentiation of cloned cell populations grown from fibroblastic and adipocytic colonies has been made using an in vivo diffusion chamber assay. The adipocytic colonies differentiated and grew to a limited size in medium with rabbit plasma and hydrocortisone, but attempts to isolate them and expand them in this medium failed. When the serum supplement was changed to foetal calf serum at day 10 the cells in the adipocytic colonies acquired a less differentiated morphology, there was a large increase in colony growth and cells were produced in sufficient numbers for the diffusion chamber assay. Thirty one fibroblastic colonies and twenty one adipocytic colonies were isolated either by limiting dilution or ring cloning and then expanded. Of these, eleven fibroblastic and eight adipocytic colonies provided enough cells (2×106 to 2×IO” for implantation and culture in the chambers. Four of the eleven fibroblastic and three of the eight adipocytic colonies formed an osteogenic tissue in the chambers. It was concluded that cells that have differentiated in an adipocytic direction are able to revert to a more proliferative stage and subsequently to differentiate along the osteogenic pathway. Adipocytic and fibroblastic cells cultured in vitro from marrow have, with osteogenic cells, a common precursor in adult marrow.
Production of heparan sulphate proteoglycans by human bone marrow stromal cells
Authors: Morris A. J. , Turnbull J. E. , Riley G. P. , Gordon M. Y. , Gallagher J. T.
Published: April 2021

Haemopoietic progenitors from human bone marrow bind strongly to human marrow stromal cell cultures but the interaction only occurs if the stromal cells are maintained in methyl prednisolone. Heparan sulphate has been implicated in this interaction and in the binding of haemopoietic cell growth factors. In the present study we have compared the molecular structures of the heparan sulphate proteoglycans, metabolically labelled with [35S]sulphate, produced by methyl prednisolone-treated and untreated human marrow stromal cells in vitro. [35S]proteoglycans were examined in the cell layers (extracted with 1% (v/v) Triton X-100 in 6M urea) and in the culture medium. Fractionation of proteoglycans by ionexchange chromatography indicated that the heparan sulphate produced by the treated cultures eluted at a higher NaCl concentration than the counterpart from untreated cells. The heparan sulphate appeared to be mainly expressed on the cell surface, since it was efficiently extracted by treatment with dilute trypsin (50 μg ml−1 for 10 min). All cultures contained two heparan sulphate proteoglycan species, the major component eluted from a Sepharose CL-4B column with a median Kav of 0.33 and apparently contained an average of only one heparan sulphate chain. Small quantities of a larger proteolgycan, which was eluted in the void volume from the CL-4B column, was also detected, mainly in the cell layer extracts. The molecular structure of the heparan sulphate chains was analysed by oligosaccharide mapping, following specific enzymic depolymerisation, and separation of breakdown products by gradient PAGE. The maps revealed significant differences in overall enzyme susceptibilities and sulphation patterns of polysaccharides produced by methyl prednisolone-treated and untreated cultures. The heparan sulphate from the methyl predinsolone-treated cultures was particularly sensitive to the enzyme heparinase (Hep I), which cleaves highly sulphated disaccharides of structure GlcNSO3 (±6S) α (l,4)IdUA (2S). The relatively high frequency of these disaccharides may account for the stronger polyanionic properties of these heparan sulphates indicated by their more retarded elution from ionexchange columns. The changes in molecular structure of heparan sulphate expressed on the surfaces of methyl-prednisolone-treated stromal cells may contribute to their ability to promote binding of immature haemopoietic cells and could enhance the capacity of these cultures to present essential growth factors to the bound cells.
Analysis of Ni2+-induced arrest of Paramecium axonemes
Authors: Larsen JØrgen , Sattr Peter
Published: April 2021

This study examines the molecular basis for paralysis of ciliary motility by Ni2+. At concentrations above 0.1 mM, Ni2+ slowed and subsequently stopped swimming of living, axenically grown Paramecium tetraurelia. However, some cilia still beat in the presence of 0.1 mM Ni2+. When permeabilized and reactivated with 4mM ATP at pCa>7, cells resumed ciliary beat and swam forward at approximately l70±28 μ ms− 1; swimming speed increased in the presence of 10 μM cyclic AMP. Addition of Ni2+ (pNi<5) caused rapid arrest of all ciliary beat in a single position. This was fully reversible when EGTA was added to raise the pNi. Axonemes were then isolated and sliding was observed in the presence of trypsin and ATP. When pNi was lowered to about 5, sliding was reduced dramatically. This too was reversible with EGTA. Dynein was then extracted from the axonemes and used for in vitro translocation assays. At concentrations of Ni2+ where microtubule-sliding and axonemal beat were greatly inhibited or absent, microtubule translocation in vitro by 22S dynein was only slightly affected. However, translocation by 14 S dynein was stopped completely. When pNi was raised by repeated washing with solutions containing EGTA, microtubule translocation by 14 S dynein resumed. We conclude that Ni2+ induces a reversible paralysis by a direct effect on 14S dynein while 22S dynein is not a primary target
On Pedalion Mira
Authors: Hudson C. T.
Published: April 2021

In the summer of last year I had the good fortune to find a new rotifer with six limbs, and under the name of PEDALION mira I described and figured it in the September number for that year of the ‘Monthly Microscopical Journal.’ I had not, however, at that time sufficient leisure to investigate its internal structure ; and when I had the leisure, the creatures had all disappeared, greatly to my vexation, for on the publication of my paper I had many inquiries about Pedalion, accompanied with requests for a few living specimens. I could only reply that the rotifers had vanished, and that I hoped to find them in another year—an answer as little satisfactory to myself as to my correspondents, especially when it was evident from some of the letters that the writers had a half suspicion that Pedalion was not a rotifer at all, but some Entomostracous larva. I had every reason, therefore, for keeping a keen watch on the pond where I had found these strange creatures. I was certain that they were rotifers, for I had seen within them organs very similar to those of Triarthra; still it would be very mortifying not to be able to produce the animal alive to the satisfaction of all inquirers; and again and again did I contrive that my daily walk should take me past the, to me, highly interesting though rather dirty pond, which held my rotiferous hopes.
Notice of the Genus Tetrapedia (Reinsch) and of Two Kindred New Forms.
Authors: Archer William
Published: April 2021

Amongst “Unicellular” Algæ (as well in the wider as in the most strict sense), falling under the class Chlorophyl -laceæ), forms with specially figured cells—that is, otherwise than globular, ellipsoidal, or cylindrical, with more or less abruptly or broadly rounded ends—are, as is well known, numerous. One has only to call to mind, not to speak of almost the entire family of Desmidiaceæ, such forms as those appertaining to the genera Polyedrium (Näg.), Scenedesmus (Meyen), Pediastrum (Meyen), Ophiocytium (Näg.), Cœlastrum (Näg.), Characium (Al. Braun), Dimorphococcus (Al.Braun), &c., for examples of very varied and at same time seemingly characteristic outlines.
On a Minute Nostoc with Spokes, with Brief Notice of Recently Published Observations On Collema, &c
Authors: Archer William
Published: April 2021

The appearance of a highly interesting and noteworthy communication from Professor Max Reess, conveying a description of certain novel experiments instituted by him on the growth of a Collema from the spores, and giving his views as to the bearing thereof as regards Nostoc,1 which I have only just seen, recalls to my recollection a seemingly remarkable though isolated example of a not uncommon minute aquatic Nostoc, with spores, brought forward by me at a recent meeting of our Microscopical Club, but not publicly exhibited, from want of time, and since then somehow overlooked to be recorded.
On, the Light emanating from the Nekve-Cells of Phyllirrhoe Bucephala
Authors: Panceri Paul
Published: April 2021

The observations of Péron, Eschcholtz, Quoy, Gaimard, Contraire, Souleyet, Leuckart, Krohn, Henry Müller, and others, have made fully known to naturalists those little pisciform sea molluscs which are denoted by the name of Phyllirrhoe, which in the Mediterranean are represented by P. bucephala.
On Young Stages of Limnocodium and Geryonia
Authors: Lankester E. Ray
Published: April 2021

Metschnikoff, in a paper in the ‘Zeitsch. wiss. Zoologie,’ 1874, p. 17, describes and figures the development of Geryonia from the egg up to the formation of tentacles and an umbrella cavity. It is, however, obvious from his figures and description that certain steps in the development were not followed by him with precision—and some of his observations are supplemented, whilst others are contradicted, by those of Fol (‘Jen. Zeitsch.,’ vol. vii). It appears to be certain, from the observations of both Metschnikoff and Fol, that in Geryonia the endoderm forms by delamination1—the embryo being, when it has so formed, a nearly spherical “diblastula” without orifice of any description (Metschnikoff’s plate ii, fig. 7). The outer layer now grows away from the inner, which remains in the form of a lenticular sac, closely applied to one pole of the ectodermal sphere. From this point forwards the accounts of Haecke] Jenaische Zeitschrift,’ vol. ii), of Metschnikoff, and of Fol, are diverse. A mouth is formed by a breaking through into the endodermal sac, and a sub-umbrellar cavity is formed, and also a velum and tentacles; but the accounts given of the mode of origin of these parts is not conclusive in any one of the authors’ memoirs above cited. Haeckel observed Geryonia embryos, in which he definitely states that the sub-umbrellar cavity existed in the form of a closed sac. Metschnikoff thinks this an erroneous observation, and due to a mistaking of the endoderm sac for the sub-umbrellar cavity. According to Metschnikoff, the ectoderm and endoderm are ruptured at the central point where the enclosed endoderm sac is resting on the inner wall of the larger ectodermal sac, and the ectoderm is invaginated to form the sub-umbrellar cavity. At the same time a ring grows up at some distance from the mouth thus formed, which becomes the margin of the umbrella, and gives off, on its adoral side, the velum; on its aboral side, the first tentacles.
On a Morphological Variety of Bacillus Anthracis
Authors: Klein E.
Published: April 2021

With. Plate XXI.

In my Report of 1881 to the Medical Officer of the Local Government Board, reprinted in this Journal, January, 1883, I have mentioned the occurrence, in artificial cultivations of Bacillus anthracis, of peculiar torula-like cells connected with the Bacillus anthracis. I have stated there (this Journal, January, p. 37) that observing the growth of the threads of Bacillus anthracis in “cell specimens,” it is found that the growing ends of the threads are occasionally seen in connection with a row of torula-like cells, i. e. spherical or elliptical cells closely placed so as to form a complete chain. The torula-like cells are larger than the cubical cells, which I there described as constituting the elements of the Bacillus anthracis.
Observations on Saprolegniæ
Authors: Marshall Ward H.
Published: April 2021

The Saprolegniæ are a family of Fungi characterised especially by their aquatic habits and correlated delicate structure; they are for the most part Saprophytes, flourishing on the decaying bodies of animals or plants in water, though several are now known as parasites on living members of both kingdoms, in which they cause profound destructive changes, sometimes ending in the death of the host.
On the Existence of Spengel’s Olfactory Organ and of Paired Genital Ducts in the Pearly Nautilus
Authors: Ray Lankester E. , Bourne A.G.
Published: April 2021

A Male and a female specimen of Nautilus pompilius were purchased a few years since by one of us for the Zoological Museum of University College, London. Leisure and opportunity for the study of these specimens have recently been afforded, and we propose to briefly report here on two interesting additions to knowledge which our observations have yielded.
On some Structures found in the Connective Tissue between the Renal Artery and Vein in the Human Subject
Authors: Gibbes Heneage
Published: April 2021

In dissecting out the renal artery and vein in a human subject I found some small bodies which I at first thought were lymphatic glands. On hardening and making sections of them, I found that they consisted of different structures. Some of them were small lymphatic glands, differing in no way from similar glands in other parts; the largest was about the size of a pea, while others were much smaller.
On Differences in the Histological Structure of Teeth occurring within a Single Family—the Gadidæ
Authors: Tomes Charles S.
Published: April 2021

Some years ago, whilst engaged upon an investigation which had a different object, I was struck by the fact that the teeth of various members of the Gadidæ presented marked differences in histological structure; but, partly from want of material and partly from other causes, I have only lately examined a sufficient number of the genera which are grouped together in this family to enable me to draw any conclusions about them.
Notes on the Batrachians of the Paraguayan Chaco, with Observations upon their Breeding Habits and Development, especially with regard to Phyllomedusa hypochondrialis, Cope. Also a Description of a New Genus
Authors: Budgett J. S.
Published: April 2021

An extremely common frog, frequently found in the streets of Concepcion at sunset and on both sides of the river Paraguay.
Crystalline Properties of Spicules of Leucosolenia complicata
Authors: Jones Walter Clifford
Published: April 2021

Spicules of Leucosolenia complicata acquire crops of crystals when left in calcium bicarbonate solution. The sites occupied by the crystals depend on the type of prior corrosion which the spicules have undergone. Thus spicules isolated by 5 per cent, potash solution develop crystals on the surfaces transverse to the optic axis (basal rays and slender monaxons excepted), those isolated by potassium nitrate solution on the surfaces parallel to the optic axis. It appears that on these surfaces respectively rhombohedral and prismatic faces are corroded and enlarged, thereby facilitating the subsequent crystallization upon them. Continued prior corrosion leads to the spread of the crystal sites around the rays.

The crystals are calcite rhombohedra and all bear the same crystallographic orientation as the calcite of the spicule on which they have crystallized. The relationship between the crystal faces and the spicule rays is a guide to the orientation of the spicule with reference to the crystallographic axes of calcite, and provided it be assumed that the crystals are positive rhombohedra, agreement has been obtained with von Ebner’s deductions, based on corrosion phenomena.

A discussion is given’ on the factors controlling spicule form, particularly with respect to the uniplanar growth of the rays and the planar angle. The facts suggest that the crystallizing solution favours crystallization mainly on the pair of surfaces transverse to the optic axis, and the curvature in the plane containing the optic axis is caused by the choanoderm deflecting the calcoblast on the ray tip and thereby hindering the crystallization on one or other surface. The elliptical cross-section of the rays (basal rays and slender monaxons excepted) indicates the same preferential crystallization. To explain the planar angle it seems necessary to postulate the existence of a spiralling submicroscopic fibrillar system in the oscular tube, the fibrils being parallel to the spirals on which the spicules and pores tend to lie. A preliminary account of the spiral organization of the tube is given.

It is concluded that the spicule form can be explained by a combination of extrinsic and intrinsic factors, the latter depending on the properties of the crystallizing material, the former on the gene complex.
The Function and Metabolism of Certain Insect Muscles in Relation to their Structure
Authors: Edwards George A. , Ruska Helmut
Published: April 2021

Electron microscopic observations on ultrathin sections of the red thoracic flightmuscles and white leg muscles of Hydrophilus and Dytiscus are reported.

In red muscle-fibres with high values in frequency of contraction, oxygen consumption, and dehydrogenase activity, the single fibrils are completely surrounded by huge mitochondria. Tracheoles penetrate the sarcolemma and supply the mitochondria with oxygen by intracellular branches. In the less active white muscle fibres, mitochondria are found irregularly scattered between the fibrils or along the I band. The intracellular tracheolization is sparse but an endoplasmic reticulum is widely spread between the synfibrillar contractile material. The same muscles of the two insects differ considerably in detail.
Haemoglobin in the Fat-Cells of Daphnia
Authors: Green J.
Published: April 2021

When placed in well aerated water, Daphnia can lose haemoglobin from its blood by two methods. The haemoglobin may be passed into the eggs or it may be broken down in the fat-cells. When populations of D. curvirostris or D. pulex, with much haemoglobin in the blood, are placed in conditions in which they can produce very few eggs and are then placed in well aerated water, haemoglobin appears as globules in the fat-cells. This appears to be an emergency measure to remove haemoglobin from the blood until the fat-cells can break it down. When equally red animals, producing ten eggs each, are placed in well aerated water, globules of haemoglobin do not appear in the fat-cells. Sufficient haemoglobin is drained from the blood into the eggs to render the formation of haemoglobin globules in the fat-cells unnecessary.
The Identification of Thyrotrophin-secreting Cells in the Pituitary Gland of the Minnow (Phoxinus phoxinus)
Authors: Barrington E. J. W. , Matty A. J.
Published: April 2021

Evidence is given for the existence of two main types of cyanophil cell in the median zone of the glandular lobe (adenohypophysis) of the minnow, distinguishable by their distribution and by their cytological characteristics. Both types are positive to the periodic acid Schiff (PAS) technique, but one (type 2 of this account) also gives a positive response to the aldehyde-fuchsin (AF) technique of Gomori, as used by Halmi and by Purves and Griesbach in studies of the mammalian pituitary. In fish which have been immersed in thiouracil solution the type 2 cells show degranulation and vacuolation, and their characteristic positive AF response is very greatly weakened or lost. For these reasons the type 2 cells are believed to be responsible for the secretion of thyrotrophin, and appear to be very closely comparable with the thyrotroph cells of the pituitary of the rat.
Cytological Fixation by Chromic Acid and Dichromates
Authors: Casselman W. G. Bruce
Published: April 2021

0·07 M (1 per cent.), 0·17 M (2·5 per cent.), and 0·34 M (5 per cent.) solutions of analytical-grade potassium dichromate have pH values of 4·10, 4·05, and 3·85 respectively. The values for corresponding solutions of chromic acid are 1·20, 0·85, and 0·70. The oxidation potential for potassium dichromate is 0·76 V, and for chromic acid, 1·10 V.

During fixation for 18–20 hours at room temperature, with either reagent, there is a small decrease in hydrogen-ion concentration but no appreciable change in oxidation potential. During postchroming for 48 hours at 37° C., there is a further decrease in hydrogen-ion concentration, but only in the case of chromic acid is there a decrease in oxidation potential.

The morphological features of the fixed cells are determined almost entirely by the fixing reagent. Postchroming can influence staining properties. There are two characteristic fixation ‘pictures’ depending upon the pH of the reagent: (1) with chromic acid and the more acidic dichromates (barium, calcium, mercuric, or silver) there is destruction of the mitochondria and disorganization of the cytoplasm and nuclear contents, resisted only by the nucleolus, and (2) with potassium dichromate and the other less acidic dichromates (ammonium, lithium, or sodium), the mitochondria, cytoplasm, and nucleus are well fixed. With various tissues from mice, the transition between the two types occurs around pH 3·4–3·8.

The chemical mechanism of cytological fixation by anionic chromium reagents remains to be elucidated. Oxidative reactions do occur. Probably more important are ionic interactions and complex formations, often with associated precipitation, involving various tissue constituents and the several chromium ions.
Single-cell transcriptome sequencing on the Nanopore platform with ScNapBar
Authors: Wang Qi , Bönigk Sven , Böhm Volker , Gehring Niels , Altmüller Janine , Dieterich Christoph
Published: April 2021

The current ecosystem of single-cell RNA-seq platforms is rapidly expanding, but robust solutions for single-cell and single-molecule full-length RNA sequencing are virtually absent. A high-throughput solution that covers all aspects is necessary to study the complex life of mRNA on the single-cell level. The Nanopore platform offers long read sequencing and can be integrated with the popular single-cell sequencing method on the 10× Chromium platform. However, the high error-rate of Nanopore reads poses a challenge in downstream processing (e.g., for cell barcode assignment). We propose a solution to this particular problem by using a hybrid sequencing approach on Nanopore and Illumina platforms. Our software ScNapBar enables cell barcode assignment with high accuracy, especially if sequencing saturation is low. ScNapBar uses unique molecular identifier (UMI) or Naïve Bayes probabilistic approaches in the barcode assignment, depending on the available Illumina sequencing depth. We have benchmarked the two approaches on simulated and real Nanopore data sets. We further applied ScNapBar to pools of cells with an active or a silenced nonsense-mediated RNA decay pathway. Our Nanopore read assignment distinguishes the respective cell populations and reveals characteristic nonsense-mediated mRNA decay events depending on cell status.
İslâm Coğrafyasında Salgınlar Tarihinin Sessiz Kaynakları: Taun/Veba Risaleleri Literatürü
Authors: Arıcı Mustakim
Published: April 2021

1347’den itibaren İslâm ve Batı coğrafyalarında yeni bir literatür ortaya çıktı, taun ya da Türkçede daha çok kullandığımız şekliyle veba risaleleri. İslâm coğrafyasındaki literatür şu üç şeyden beslendi: (i) Jüstinyanus Salgının İslâm’ın doğuşundan beri yaşanan bir olgu olması sayesinde taun, haliyle hadis kaynaklarının, siyer ve tarih eserlerinin gündeminde oldu. Bu gündem, risalelere özel olarak taun ve salgınlar, daha genel olarak da hastalıklarla mücadelenin itikadî ve fıkhî bir zeminde tartışılması şeklinde yansıdı. (ii) Taunu ya da hıyarcık vebasını tanımlamayı ve bununla bir şekilde başa çıkmayı hedefleyen eserler hastalığı Galenos-İbn Sînâ tıbbı temelinde miyazma doktrini ekseninde açıklamaya çalıştı ve dayanaklarını bu tıp paradigmasından devşirdi. (iii) Ve nihayet amansız bir hastalıkla karşı karşıya kalınması okültist kültüre başvurmak da dâhil olmak üzere tüm çarelerin aranmasına kapı araladı. Bu arka planın tümü farklı seviyelerde de olsa risalelerin dilini ve muhtevasını belirledi. Bu makalede öncelikle modern araştırmalarda İslâm coğrafyasında yazılan veba risaleleri hakkındaki çalışmalara dair bir değerlendirme yapıldı. Ardından bazı İslâm tarihi kaynakları “veba” ve “taun” kavramlarına nasıl bir anlam yükledikleri açısından süzgeçten geçirildi. Veba risalelerine tıbbî doktrinler ve terminoloji açısından kaynaklık eden tıp eserlerinin bir kısmı da bu iki kavram ekseninde aynı şekilde değerlendirmeye konu oldu. Böylece Kara Ölüm (1346-1353) öncesi İslâm dünyasında genel olarak “salgın”, “veba” ve “taun” hakkındaki tasavvurun anlaşılması hedeflendi. Makalenin asıl konusu olan taun/veba risaleleri literatürü hem özellikleri itibariyle tartışıldı ve analiz edildi hem de literatüre dair bir veri tabanı oluşturuldu. Memlük ve Osmanlı dönemleri eserleri başta içerik olmak üzere bazı açılardan bir süreklilik ilişkisi arz ederken Osmanlı risaleleri belli hususiyetleriyle Memlük eserlerinden ayrılmaktadır. Bu çalışmada iki dönemdeki eserlerin ortak yönlerine de temas edilmekle birlikte literatürün ayrıştıkları noktalar da tahlil edildi.
NILAI PERUSAHAAN DITINJAU DARI PROFITABILITAS, KEPUTUSAN INVESTASI DAN KEPUTUSAN PENDANAAN
Authors: Krisdiyanto Krisdiyanto , Wiyono Gendro , Rinofah Risal
Published: April 2021

This research was aimed to analyze of profitability, investment decisions, and funding decisions on firm value. This research belongs to empirical study research. The population in this research is transportation sub-sector which is 43 companies listed on the Indonesia Stock Exchange (IDX). The sample used is to use a purposive sampling method, namely the sampling technique for data sources with certain considerations. Quantitative analysis of the r Square, and hypothesis testing in the form of the F test and t test. The results showed that there was a positive and significant effect on profitability there was also a positive and significant influence on investment decisions, there was also a positive and significant influence on funding decisions, and there is also a positive and significant effect on profitability, investment decisions, and funding decisions on the value of the BEI 2016-2018 transport sub-sector company
PENGARUH MEKANISME CORPORATE GOVERNANCE TERHADAP KINERJA KEUANGAN PERUSAHAAN KELUARGA DI INDONESIA
Authors: Christian Santoso Adhitya Rechandy
Published: April 2021

This study discusses the application of corporate governance to the performance of family companies in Indonesia. The relationship of corporate governance in this study was proxied with an independent board of commissioners, the size of the board of directors, and the size of the audit board. The measurement of the financial performance of this study uses Return On Assets (ROA) with a sample of research companies listed on the Indonesia Stock Exchange in the 2014-2018 period.The sampling method in this study uses purposive sampling and data analysis using multiple linear regression with the help of SPSS 21.The results of data analysis, the proportion of independent commissioners and the size of the board of directors had a significant positive effect on the variable size of the audit board not having a significant effect.
PENGARUH LIKUIDITAS (CURRENT RATIO) TERHADAP RETURN SAHAM: PERAN PEMEDIASI PROFITABILITAS (RETURN ON EQUITY) PADA PERUSAHAAN SUB SEKTOR KONSTRUKSI BANGUNAN DI BURSA EFEK INDONESIA PERIODE 2016-2018
Authors: Hidayat Taufik
Published: April 2021

This study aims to determine the effect of the liquidity ratio (CR) on stock returns with the role of profitability (ROE) as a mediator. This study takes the object of building construction sub-sector companies listed on the Indonesia Stock Exchange for the period of 2016-2018. The population in this research is all companies in the building construction sub sector listed on the Indonesia Stock Exchange in the 2016-2018 period as many as 17 companies. The sampling technique uses purposive sampling using several criteria, namely the building construction sub-sector companies listed on the Indonesia Stock Exchange in the 2016-2018 period, companies that submit financial reports during the research period and companies that have positive net income reports. The number of samples that fit the criteria were 10 companies. The data analysis tool uses panel data regression analysis using Eviews 6. The results of the study show that the current ratio has a negative effect on stock returns, the current ratio has a positive effect on return on equity, return on equity has a negative effect on stock returns.
PENGARUH PENERAPAN MANAJEMEN RISIKO TERHADAP KINERJA KEUANGAN SEKTOR PERBANKAN PERIODE 2013-2017
Authors: Ismanto Deny
Published: April 2021

This study discusses liquidity risk, credit risk, operational risk, and interest rates risk on finance performance at the National Private Foreign Exchange Commercial Bank listed on the Indonesia Stock Exchange for the period 2013-2017. In this study, the independent variables are liquidity risk, credit risk, operational risk and interest rate risk and the dependent variable is financial performance. The object of research is the National Private Foreign Exchange Private Bank listed on the Indonesia Stock Exchange for the period 2013-2017. The population in this study was 23 banks. The sampling technique using purposive sampling method, based on research criteria, the research sample won 11 banks. The analysis tool used is panel regression data with eviews 6. The data used in this study is secondary data obtained from the official website pages of the Indonesia Stock Exchange and Bank Indonesia. Partially, the results of the study indicate that negative liquidity risk is not significant to finance, negative credit risk is significant to finance, operational risk is significantly negative to financial performance, and interest rates increase significantly positive to finance. Simultaneously liquidity risk, credit risk, operational risk and interest rate risk affect financial performance.
PERAN MEDIASI MOTIVASI KERJA PADA PENGARUH GAYA KEPEMIMPINAN TRANSAKSIONAL DAN KOMPENSASI TERHADAP KINERJA KARYAWAN
Authors: Ulfah Ratna Andriya , Subiyanto Didik , Kurniawan Ignatius Soni
Published: April 2021

This study aims to examine the effect of transactional leadership style and compensation on employee performance mediated by work motivation on the employees of the Sleman Regency. Sampling in this study uses probability method because the population of employees in the Regional Water Supply Company (PDAM) Sleman Regency is quite a lot to be studied. Data collection techniques using a questionnaire distributed by the Director of PDAM Sleman. Data analysis techniques using the application SPSS version 21 include validity test, reliability test, descriptive statistics, classic assumption test, multiple linear regression test, hypothesis test, and coefficient of determination. The results of this study indicate that the transactional leadership style variable has a positive and significant effect on work motivation, compensation has a positive and significant effect on work motivation, transactional leadership has a positive and significant effect on employee performance, work motivation has a positive and significant effect on employee performance, compensation has a positive and significant effect on employee performance, transactional leadership has a positive and significant effect on employee performance mediated by motivation, compensation has a positive and significant effect on employee performance mediated by motivation. The most dominant influence is work motivation variable, then compensation variable is followed
MEMPREDIKSI PENYIMPANGAN INTERPERSONAL DARI KEADILAN PROSEDURAL DAN KEADILAN INFORMASIONAL
Authors: Nurmaya Ema
Published: April 2021

This study aims to investigate the relationship between procedural and informational justice and interpersonal deviations. Specifically, this study hypothesizes that: (a) There is a negative relationship between procedural justice and interpersonal deviation behavior, (b) There is a negative relationship between informational justice and interpersonal deviationbehavior. To test the hypothesis, SPSS was used to analyze survey data from 124 hospital nurses at public private hospitals in Yogyakarta. The results show that all hypotheses are proven. And furthermore, this study produces suggestions both theoretically and practically.
ANALISIS PERBEDAAN HARGA SAHAM, RETURN SAHAM, DAN ABNORMAL RETURN SEBELUM DAN SESUDAH STOCK SPLIT PADA PERUSAHAAN HIGH PROFILE DAN LOW PROFILE YANG TERDAFTAR DI BURSA EFEK INDONESIA
Authors: Rahmawati Pita , Nusantoro Jawoto , Sari Gustin Padwa
Published: April 2021

This research aims to determine whether there are differences in stock prices, stock returns and abnormal returns before and after a stock split in high profile and low profile companies. The research period used in this study was on 2016-2018. The research was analyzed in quantitative method by using a purposive sampling method. Based on the sampling criteria, 40 companies were selected as research samples. Kolmogorov Smirnov One Sample test was used for the normality test. After the normality test was carried out, the data was processed using the two paired-sample difference test. The t-test (paired sample t-test) was used if data were normally distributed but if it was not normally distributed the Wilcoxon Signed Rank test would be used. Hypothesis testing results showed that (1) there are differences in stock prices whether before and after a stock split in high profile companies (2) there are differences in stock prices whether before and after the stock split in low profile companies (3) there are differences in stock returns whether before and after a stock split in the company high profile (4) there is no difference in stock returns whether before and after the stock split in low profile companies (5) there is no difference in abnormal returns whether before and after the stock split in high profile companies (6) there is no difference in abnormal returns whether before and after the stock split in low profile companies (7) there are differences in stock prices after a stock split in high profile companies and low profile (8) there is no difference in stock returns whether before and after the stock split in high profile and low profile companies (9) there is no difference in abnormal stock returns whether before and after a stock split at high profile and low profile companies.
PENGARUH KREDIBILITAS INFLUENCER PADA EFEKTIVITAS IKLAN MEDIA SOSIAL INSTAGRAM DALAM MEMBENTUK MINAT BELI KONSUMEN (STUDI PADA PENGIKUT INSTAGRAM AYUDIA BING SLAMET)
Authors: Jelita Alhensa Ferninda , Rimiyati Hasnah
Published: April 2021

This study aims to analyze the influence of influencers' credibility on the effectiveness of Instagram social media advertising in shaping consumer buying interest (Study on Instagram followers Ayudia Bing Slamet). The subjects in this study were students using social media Instagram who were in the Special Region of Yogyakarta. This research was conducted with a sample size of 200 respondents who were determined by sampling technique using non probability sampling technique with purposive sampling method and distributing questionnaires to respondents using Google Forms. The analytical tool used is Structural Equation Modeling (SEM) with the AMOS 24 application program. Based on the analysis, it was found that the attractiveness of influencers had a positive effect on consumer attitudes towards advertising, trustworthiness towards influencers had a positive effect on consumer attitudes towards advertising, influencer expertise had a positive effect on consumer attitudes towards advertising, and attitudes towards advertising had a positive effect on buying interest.
Examining Farmers’ Resilience to Climate Change and Policy Ramifications in North-West Cameroon
Authors: Awazi Nyong Princely , Temgoua Lucie Felicite , Shidiki Abubakar Ali
Published: April 2021

Over half of the world’s population depends on smallholder farms for their daily food needs. However, high levels of vulnerability and low levels of resilience to the adverse effects of climatic variations and changes constitute major threats to smallholder farms and farmers. It is within this context that this paper assessed the levels of resilience of smallholder farmers as well as the factors affecting smallholder farmers’ resilience to climate change in north western Cameroon. A mixed research approach was adopted during data collection, and data analysis was done using descriptive and inferential statistics. It was found that climate extremes were the order of the day, and farmers perceived income level, practice of agroforestry and land accessibility as the main determinants of resilience. The main resilience option practiced by most smallholder farmers was agroforestry. Chi-square and t-test statistics showed the existence of a statistically significant difference (p<0.05) between smallholder farmers resilience to climate change and different environmental, institutional and socio-economic variables. Logistic regression coefficients showed the existence of a statistically significant cause-effect relationship (p<0.05) between farmers’ resilience to climate change and different environmental, institutional and socio-economic variables such as income level, land accessibility, credit accessibility, information accessibility and number of farms. From the foregoing, income level, land accessibility, credit accessibility, information accessibility and number of farms play a significant role towards enhancing smallholder farmers’ resilience to climate change. Policy makers therefore need to factor in these variables when crafting policies geared towards improving smallholder farmers’ resilience to climate change.
Developing Empirical Formula of Ventilation Index for Assessing PM2.5 Exposure in Biomass-Fuel Using Households
Authors: Ramasamy Rengaraj , Mukhopadhyay Krishnendu
Published: April 2021

Equations of ‘ventilation index’ in industrial and medical sectors are already established, but not yet been worked out for domestic household environments. This study intended to establish an empirical formula for ‘ventilation index’ for domestic indoor environments. Measurements of 2.5 micron size particulate matter (PM2.5) with biomass, air velocity, room index, temperature and relative humidity were used for developing the empirical formula. A total of 54 households from rural Andhra Pradesh and Karnataka states of India were selected. Average air velocity ranges in selected kitchens were categorised into three parts for developing ventilation indices in household kitchen environments. Observations in kitchen environments were found to be very interesting and promising. The formula captured inverse relation between PM2.5 and air velocities, consistently.