bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

ABSTRACT
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

ABSTRACT
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&gt;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&lt;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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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

ABSTRACT
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.
Prevalence of intestinal parasitic infection and its associated factors among primary school students in Ethiopia: A systematic review and meta-analysis
Authors: Assemie Moges Agazhe , Shitu Getahun Daniel , Hune Yidersail , Petrucka Pammla , Abebe Ayele Mamo , Telayneh Animut Takele , Ambaw Mekdes Marew , Ketema Daniel Bekele , Getaneh Temesgen , Mengist Belayneh , Alene Muluneh , Habtegiorgis Samuel Derbie 
Published: April 2021

Introduction
Intestinal parasitic infection are a major public health concern affecting both children and adolescents in Ethiopia. The aim of this systematic review and meta-analysis was to determine pooled prevalence and associated factors of intestinal parasitic infection in this target group.

Method
We systematically retrieved available articles on the prevalence of intestinal parasitic infection following database searches using PubMed, Scopus, Cochrane Library, and Science Direct between March 1 and May 27, 2020. Two authors independently extracted all relevant data using a standardized Microsoft Excel data extraction form. Heterogeneity among included studies was assessed with the Higgins I2 tests. The pooled estimates and associated factors were assessed with a random-effects model using Stata/se Version 14.

Result
We retrieved 30 eligible articles with a pooled sample size of 14,445 primary school children with response rate of 97.8%. Entamoeba spp (16.11%), Ascaris lumbricoides (13.98%), hookworm (12.51%) and Giardia lamblia (9.98%) are the top causes of intestinal parasitic infection among primary school children in Ethiopia. The pooled prevalence for at least one intestinal parasitic infection was 46.09 (95% CI: 38.50, 53.68). Heterogeneity was assessed by doing subgroup analysis by study province/region. Thus, the highest prevalence of 66.6% (95% CI: 55.5, 77.7) occurred in Tigray region, which was followed by Southern Nations, Nationalities, and Peoples’ Region at 50.8% (95% CI: 33.1, 68.5). No latrine availability (OR = 4.39: 2.50,7.73), no fingernail hygiene (OR = 2.37: 1.67, 3.35), open defecation (OR = 1.67:1.64,4.36), no formal maternal education (OR = 2.02: 1.18,3.47), rural residence (OR = 1.88: 1.46, 2.41), no habit of wearing shoes (OR = 2.66: 1.79, 3.96), non-pipe source of drinking water (OR = 1.99: 1.42,2.76), no regular hand washing practices (OR = 3.45:1.85,6.47), and no habit of washing fruits and vegetables (OR = 1.59:1.01,2.49) were associated with parasitic infection.

Conclusions
The prevalence of intestinal parasitic infection was high (46%). Attention should be given to promoting personal hygiene, latrine utilization, wearing shoes, avoiding eating raw food, creating awareness for those mothers who lack formal education. Moreover, future research ideally will expand on the topic by conducting research in regions which have no prior research.