bluuebunny/crossref_metadata_2025_split huggingface dataset:
The transcriptional landscape of the cultured murine middle ear epithelium in vitro
Authors: Mulay Apoorva , Chowdhury Md Miraj K. , James Cameron T. , Bingle Lynne , Bingle Colin D. 
Published: April 2021

ABSTRACT
Otitis media (OM) is the most common paediatric disease and leads to significant morbidity. Although understanding of underlying disease mechanisms is hampered by complex pathophysiology, it is clear that epithelial abnormalities underpin the disease. The mechanisms underpinning epithelial remodelling in OM remain unclear. We recently described a novel in vitro model of mouse middle ear epithelial cells (mMEECs) that undergoes mucociliary differentiation into the varied epithelial cell populations seen in the middle ear cavity. We now describe genome wide gene expression profiles of mMEECs as they undergo differentiation. We compared the gene expression profiles of original (uncultured) middle ear cells, confluent cultures of undifferentiated cells and cells that had been differentiated for 7 days at an air liquid interface (ALI). &gt;5000 genes were differentially expressed among the three groups of cells. Approximately 4000 genes were differentially expressed between the original cells and day 0 of ALI culture. The original cell population was shown to contain a mix of cell types, including contaminating inflammatory cells that were lost on culture. Approximately 500 genes were upregulated during ALI induced differentiation. These included some secretory genes and some enzymes but most were associated with the process of ciliogenesis. The data suggest that the in vitro model of differentiated murine middle ear epithelium exhibits a transcriptional profile consistent with the mucociliary epithelium seen within the middle ear. Knowledge of the transcriptional landscape of this epithelium will provide a basis for understanding the phenotypic changes seen in murine models of OM.
Autumn migratory orientation and route choice in early and late dunlinsCalidris alpinacaptured at a stopover site in Alaska
Authors: Åkesson Susanne , Grönroos Johanna , Bianco Giuseppe 
Published: April 2021

ABSTRACTWe investigated the migratory orientation of early and late captured dunlins, Calidris alpina, by recording their migratory activity in circular orientation cages during autumn at a staging site in southwest Alaska and performed route simulations to the wintering areas. Two races of dunlins breeding in Alaska have different wintering grounds in North America (Pacific Northwest), and East Asia. Dunlins caught early in autumn (presumably Calidris alpinapacifica) oriented towards their wintering areas (east-southeast; ESE) supporting the idea that they migrate nonstop over the Gulf of Alaska to the Pacific Northwest. We found no difference in orientation between adult and juveniles, nor between fat and lean birds or under clear and overcast skies demonstrating that age, energetic status and cloud cover did not affect the dunlins’ migratory orientation. Later in autumn, we recorded orientation responses towards south-southwest suggesting arrival of the northern subspecies Calidris alpinaarcticola at our site. Route simulations revealed multiple compass mechanisms were compatible with the initial direction of early dunlins wintering in the Pacific Northwest, and for late dunlins migrating to East Asia. Future high-resolution tracking would reveal routes, stopover use including local movements and possible course shifts during migration from Alaska to wintering sites on both sides of the north Pacific Ocean.
Influence de la Papaïne sur le Tibia Embryonnaire de Poulet cultivé in Vitro
Authors: Girard par Henri 
Published: April 2021

ABSTRACT
The action of papain on the tibia of fowl embryos has been studied. The effect of papain-containing media upon the explanted 7-day tibia is very rapid. After 1 hour exposure to fluid medium or 4 hours in contact with a solid one (containing 1·2 mg./ml. papain) the matrix of the cartilage has disappeared completely. Growth on solid medium is much reduced and matrix is not formed. On transfer after 1 or 2 days to a fresh, papain-free medium, based on embryo extract, the tibia resumes its growth at about the normal rate, but does not always regain the size of the control. Chondrocytes do not appear to have been injured by papain since they resume secretion of matrix. An enriched medium, whose formula is given, facilitates the resumption of matrix secretion, but reduces the growth rate of the tibia and has this effect also on controls. In high concentrations (3·7 mg./ml.) papain has a more lasting effect on chondrocytes. On transfer to papain-free medium the growth rate of tibias is less fully restored. Several synthetic milieux were examined, but because of their relative lack of nutritive substances, none proved favourable for the resumption of growth of 7-day tibias. Tibias of 5-day embryos are not so severely affected by papain. After transfer to normal medium their growth rate is equal to that of controls. Papain, finally, has an action on 7-day embryonic cartilage which is, within limits, reversible.
Transforming Growth Factor-β signalling in extraembryonic mesoderm is required for yolk sac vasculogenesis in mice
Authors: Goumans Marie-José , Zwijsen An , Rooijen Marga A. van , Huylebroeck Danny , Roelen Bernard A. J. , Mummery Christine L. 
Published: April 2021

Abstract
We have analysed the function of transforming growth factor β (TGF-β) in yolk sac development in mice by generating somatic chimaeras in which the extraembryonic mesoderm, which gives rise to the endothelial and haematopoietic cells of the yolk sac vasculature, is derived from embryonic stem (ES) cells. The ES cells were stably transfected and express either the full-length type II binding receptor or a kinase-deficient mutant of this receptor. Examination of yolk sacs from chimaeras between E8.5 and 9.5, and analysis of marker expression in embryoid bodies from these mutant ES cell lines in prolonged suspension culture demonstrated that (1) a major function of TGF-β in yolk sac mesoderm is to regulate production and deposition of fibronectin in the extracellular matrix that maintains yolk sac integrity, (2) TGF-β signalling is not required for differentiation of extraembryonic mesoderm into endothelial cells but is necessary for their subsequent organisation into robust vessels, and (3) TGF-β signalling must be tightly regulated for the differentiation of primitive haematopoietic cells to take place normally. Together, these results show that defective TGF-β signalling in the extraembryonic mesoderm alone is sufficient to account for the extraembryonic phenotype reported previously in TGF-β1−/− mice (Dickson, M. C., Martin, J. S., Cousins, F. M., Kulkarni, A. B., Karlsson, S. and Akhurst, R. J. (1995) Development 121, 1845-1854).
Parathyroid hormone-related protein signaling is necessary for sexual dimorphism during embryonic mammary development
Authors: Dunbar Maureen E. , Dann Pamela R. , Robinson Gertraud W. , Hennighausen Lothar , Zhang Jian-Ping , Wysolmerski John J. 
Published: April 2021

Abstract
Male mice lack mammary glands due to the interaction of circulating androgens with local epithelial-mesenchymal signaling in the developing mammary bud. Mammary epithelial cells induce androgen receptor (AR) within the mammary mesenchyme and, in response to androgens, the mesenchyme condenses around the epithelial bud, destroying it. We show that this process involves apoptosis and that, in the absence of parathyroid hormone-related protein (PTHrP) or its receptor, the PTH/PTHrP receptor (PPR1), it fails due to a lack of mesenchymal AR expression. In addition, the expression of tenascin C, another marker of the mammary mesenchyme, is also dependent on PTHrP. PTHrP expression is initiated on E11 and, within the ventral epidermis, is restricted to the forming mammary epithelial bud. In contrast, PPR1 expression is not limited to the mammary bud, but is found generally within the subepidermal mesenchyme. Finally, transgenic overexpression of PTHrP within the basal epidermis induces AR and tenasin C expression within the ventral dermis, suggesting that ectopic expression of PTHrP can induce the ventral mesenchyme to express mammary mesenchyme markers. We propose that PTHrP expression specifically within the developing epithelial bud acts as a dominant signal participating in cell fate decisions leading to a specialized mammary mesenchyme.
Prostatic growth and development are regulated by FGF10
Authors: Thomson A. A. , Cunha G. R. 
Published: April 2021

Abstract
We have examined the role of Fibroblast Growth Factor 10 (FGF10) during the growth and development of the rat ventral prostate (VP) and seminal vesicle (SV). FGF10 transcripts were abundant at the earliest stages of organ formation and during neonatal organ growth, but were low or absent in growth-quiescent adult organs. In both the VP and SV, FGF10 transcripts were expressed only in a subset of mesenchymal cells and in a pattern consistent with a role as a paracrine epithelial regulator. In the neonatal VP, FGF10 mRNA was expressed initially in mesenchymal cells peripheral to the peri-urethral mesenchyme and distal to the elongating prostatic epithelial buds. At later stages, mesenchymal cells surrounding the epithelial buds also expressed FGF10 transcripts. During induction of the SV, FGF10 mRNA was present in mesenchyme surrounding the lower Wolffian ducts and, at later stages, FGF10 transcripts became restricted to mesenchymal cells subadjacent to the serosa. We investigated whether the FGF10 gene might be regulated by androgens by analysing the levels of FGF10 transcripts in SV and VP organs grown in serum-free organ culture. While FGF10 transcript levels increased after treatment with testosterone in the SV (but not VP), these changes were not sensitive to anti-androgen treatment, and thus it is likely that FGF10 mRNA was not directly regulated by testosterone. Also, FGF10 mRNA was observed in the embryonic female reproductive tract in a position analogous to that of the ventral prostate in males suggesting that FGF10 is not regulated by androgens in vivo. Recombinant FGF10 protein specifically stimulated growth of Dunning epithelial and BPH1 prostatic epithelial cell lines, but had no effect on growth of Dunning stromal cells or primary SV mesenchyme. Furthermore, FGF10 protein stimulated the development of ventral prostate and seminal vesicle organ rudiments in serum-free organ culture. When both FGF10 and testosterone were added to organs in vitro, there was no synergistic induction of development. Additionally, development induced by FGF10 was not inhibited by the addition of the anti-androgen Cyproterone Acetate demonstrating that the effects of FGF10 were not mediated by the androgen receptor. Taken together, our experiments suggest that FGF10 functions as a mesenchymal paracrine regulator of epithelial growth in the prostate and seminal vesicle and that the FGF10 gene is not regulated by androgens
Abbreviations: SV, Seminal vesicle; VP, ventral prostate; FGF10, Fibroblast growth factor 10; KGF, Keratinocyte growth factor; FGFR2, Fibroblast growth factor receptor 2; SVM, Seminal vesicle mesenchyme; VMP, Ventral mesenchymal pad.
An Electron Microscope Study of the Cartilaginous Matrix in the Developing Tibia of the Fowl
Authors: Martin Angela V. W. 
Published: April 2021

ABSTRACT
The methods of optical and electron histology have been applied to the study of structural changes in the cartilaginous matrix of the developing fowl tibia. A fine fibrous component without distinctly recognizable periodic structure occurs in the cartilage matrix throughout development and in adult life. Collagen-fibres appear later than the ‘unbanded’ fibrils and develop differently in the different regions of the tibia. The possible significance of these observations is discussed.
Transplantation of Living Nuclei of Late Gastrulae into Enucleated Eggs of Rana pipiens
Authors: King Thomas J. , Briggs Robert 
Published: April 2021

ABSTRACT
In previous papers it has been shown that living nuclei of animal hemisphere cells of frog blastulae and early gastrulae can be transferred into enucleated eggs (Briggs & King, 1952,1953a). Approximately 20 per cent, to 40 per cent, of the recipient eggs cleave normally, and the majority of these develop into complete embryos, demonstrating that the transplanted nuclei are undifferentiated (i.e. still capable of participating in all types of differentiation). This result is more or less expected since the nuclei in question come from undifferentiated parts of the blastula and early gastrula.
Growth and development of pattern in the cranial neural epithelium of rat embryos during neurulation
Authors: Morriss-Kay Gillian M. 
Published: April 2021

ABSTRACT
The pattern of growth and morphogenesis of the cranial neural epithelium of rat embryos during neurulation is described. Transverse sections of the midbrain/hindbrain neural epithelium at different stages (0–14 somites) show a constant area and cell number throughout neurulation, even though there is a high level of mitosis. Mitotic spindles are orientated parallel to the long axis of the embryo, so that increase in cell number occurs in this direction only. Growth is expressed only as an increase in size of the forebrain, which projects rostrad to the tip of the notochord.
In the midbrain/upper hindbrain regions, cellular organization of the neural epithelium changes from columnar to cuboidal to pseudostratified, while its shape changes from flat to biconvex to V shaped. Closure is immediately preceded by neural crest cell emigration from the lateral edges. Throughout neurulation the cranial notochord develops an increasingly convex curvature in the rostrocaudal plane. The attached neural epithelium curves with the notochord (forming the primary cranial flexure) so that as its lateral edges move dorsomedially they form a more distant concentric arc with that of the notochord, and are hence stretched during the final closure period.
The whole rat embryo culture technique was used to investigate the morphogenetic role of proteoglycans during neurulation, neural crest cell emigration and other events in the lateral edge region prior to closure, and the importance of microfilament contraction during concave curvature of the neural epithelium.
Thiopurines correct the effects of autophagy impairment on intestinal healing – a potential role for ARHGAP18/RhoA
Authors: Prins Marileen M. C. , Giugliano Francesca P. , van Roest Manon , van de Graaf Stan F. J. , Koelink Pim J. , Wildenberg Manon E. 
Published: April 2021

ABSTRACT
The ATG16L1 T300A single-nucleotide polymorphism (SNP) is associated with Crohn's disease and causes an autophagy impairment. We have previously shown that this SNP is involved in the migration and hyperactivation of Rac1 in dendritic cells. Mucosal healing, currently the main target for inflammatory bowel disease treatment, depends on restoration of the epithelial barrier and requires appropriate migration of epithelial cells towards and over mucosal lesions. Therefore, we here further investigated the impact of autophagy on epithelial migration.
ATG16L1 knockdown was established in the HT29 human colonic epithelial cell line using lentiviral transduction. Migratory capacity was evaluated using scratch assays and RhoAGTP was measured using G-LISA. Immunofluorescent ARHGAP18 and sequestome 1 (SQSTM1; also known as p62) staining was performed on HT29 cells and primary colonic tissue of Crohn's disease patients.
We observed that ATG16L1 knockdown cells exhibited decreased autophagy and decreased migration capacity. Furthermore, activity of RhoA was decreased. These characteristics were phenocopied using ATG5 knockdown and pharmacological inhibition of autophagy. The migration defect was dependent on accumulation of SQSTM1 and was alleviated upon SQSTM1 knockdown. Strikingly, thiopurines also mitigated the effects of impaired autophagy. RhoA dysregulation appeared mediated through accumulation of the upstream regulator ARHGAP18, which was observed in cell lines, human foetal organoids and primary colonic tissue.
Our results indicate that the ATG16L1 T300A Crohn's disease-associated SNP causes a decrease in migration capacity in epithelial cells, mediated by an increase in SQSTM1 and ARHGAP18 protein and subsequent reduced RhoA activation.
Nature of mutations conferring resistance to 8-azaguanine in mouse cell lines
Authors: Shin Seung-IL 
Published: April 2021

ABSTRACT
Two stable mouse cell mutants A9 and RAG, which are resistant to 8-azaguanine and deficient in hypoxanthine-guanine phosphoribosyl transferase (HGPRT), have been studied in order to establish the nature of molecular changes conferring the mutant phenotypes. A specific precipitating rabbit antiserum was prepared against the normal HGPRT purified from mouse tissues, and used to test for cross-reacting material (CRM) in the mutant lysates. Neither mutants contained detectable cross-reacting material, as demonstrated by precipitation inhibition tests. However, the L cell-derived mutant A9 was shown to have a low but significant level of HGPRT activity which was clearly different from that of the normal enzyme in the wildtype parental cell line. Compared to the wild-type enzyme, the HGPRT in A9 is extremely heat labile, and has an elevated substrate-binding constant in addition to distinct antigenic differences. Both A9 and RAG have been shown previously to revert to the normal phenotype with low frequency, thus ruling out gene deletions as a possible cause of the 8-azaguanine resistance. It is suggested that RAG could involve a recessive regulatory mutation, while A9 may contain a structurally altered HGPRT as a result of a missense mutation within the structural gene for this enzyme.
Molecular hybridization of mouse satellite DNA-complementary RNA in ultrathin sections prepared for electron microscopy
Authors: Jacob J. , Gillies Katherine , Macleod D. , Jones K. W. 
Published: April 2021

ABSTRACT
The feasibility of in situ hybridization in tissue sections prepared for electron microscopy has been examined using mouse satellite DNA-complementary RNA and mouse L cells. The results obtained are encouraging, although certain technical aspects require further clarification. In interphase cells, hybrid-forming sites occur in chromatin patches positioned along the nuclear envelope. It is also confirmed that satellite DNA occurs in nucleolus-associated chromatin. The results suggest that satellite sequences are present in intranucleolar and peri-nucleolar chromatin. A similar distribution is indicated for ribosomal cistrons.
An autoradiographical study of the localization of the uptake of glutamate by the peripheral nerves of the crab, Carcinus maenas (L.)
Authors: Evans P. D. 
Published: April 2021

ABSTRACT
An autoradiographical localization of the uptake sites of [3H]glutamate has been performed on the peripheral nerves of Carcinus maenas (L.) at both the light- and electron-microscope levels. Biochemical control analyses have also been carried out at various stages of the fixation procedure. A statistical analysis of the grain distribution between the glial (and connective tissue) and axonal compartments revealed that it was highly non-random. A comparison has been made of the grain distribution obtained with the ‘circle analysis’ method with that from the ‘hypothetical grain distribution analysis’. The latter analysis revealed that the specific activity of label in the glial compartment was about seven times that of the axonal compartment. The significance of a preferential accumulation of glutamate by the glial compartments in this tissue is discussed in relation to similar findings in other tissues.
Interpretation of the threedimensional structure of living nuclei by specimen tilt
Authors: Skaer R. J. , Whytock Susan 
Published: April 2021

ABSTRACT
A mechanism is described that enables a specimen to be tilted through a known angle and continuously observed under the highest power of the optical microscope. Objects can thus be localized accurately in space. This facility in conjunction with serial optical sectioning by Nomarski optics has been used to construct models of the arrangement of polytene chromosomes in nuclei of Drosophila, Simulium and Chironomus. Telomeres and chromocentre lie on the nuclear envelope. In Simulium they lie close to an equator of the nucleus. Despite these constraints, different nuclei in the same gland do not resemble each other closely.
Adhesion of phytophthora palmivora zoospores: detection and ultrastructural visualization of concanavalin a-receptor sites appearing during encystment
Authors: Sing V. O. , Bartnicki-Garcia S. 
Published: April 2021

ABSTRACT
The binding of concanavalin A (Con A) to the cell surface of zoospores and cysts of Phytoph-thora palmivora was studied by radiometry (l25I-Con A), ultraviolet microscopy (fluorescein-Con A) and electron microscopy (peroxidase-diaminobenzidine technique). Zoospores were found to secrete during the early stages of encystment a Con A-binding material susceptible to trypsin digestion. This glycoprotein is contained in the so-called peripheral vesicles and is probably responsible for the adhesion of the encysting zoospores to solid surfaces.
Colchicine inhibition of stalk elongation in Carchesium sp.: Effect of Ca2+ and Mg2+
Authors: Rahat M. , Friedlaender Hanna , Pimstein Rachel 
Published: April 2021

ABSTRACT
The effect of colchicine on stalk elongation in the colonial peritrich ciliate Carchesium sp. has been investigated by growing this protozoon in colchicine-containing media. The length of the stalk in control cultures was 0·4–0·9 mm. In the presence of 2’5-12’5 mM colchicine, stalk elongation was inhibited, and stalk length was inversely proportional to colchicine concentration. At concentrations above 7·5 mM colchicine, stalks measured less than 01 mm, and sometimes contained imperfect myonemes. The rate of cell fission was retarded in colchicine-containing media, but nevertheless short-stalked colonies with apparently normal zooids were formed. On transfer of such colonies to media without colchicine normal growth was resumed, but only the newly formed branches were of normal length and contractility.
The inhibitory effect of colchicine was annulled by Ca2+ and Mg2+ at 10−3 and 10−4 M, respectively. At lower concentrations of Mg2+ but in the presence of Ca2+, the effect of col-chicine was less conspicuous than at low Ca2+ concentration in presence of Mg2+. Lowering Mga+ concentration at low Ca2+ concentration, increased the inhibitory effect of colchicine.
It is concluded that colchicine-sensitive, probably tubulin-like proteins, participate in the formation of the contractile stalk of Carchesium. Ca2+ and Mg2+ probably compete with col-chicine for a common site in these proteins, or they might reduce the cell’s permeability to this drug.
Calcium-binding proteins in a vorticellid contractile organelle
Authors: Amos W. B. , Routledge L. M. , Yew F. F. 
Published: April 2021

ABSTRACT
The proteins of the contractile spasmoneme of Zoothamnium have been examined for comparison with other motile systems. Though capable of calcium-induced contraction, glycerinated preparations of the spasmoneme contain neither actin nor tubulin at levels that can be detected in polyacrylamide gels. Sixty per cent of the protein in sodium dodecyl sulphate gels migrates in a band at a molecular weight of approximately 20000, consisting largely of 2 similar protein species which are here given the name of spasmins. The amino acid composition of 2 spasmin fractions has been determined by a fluorimetric method. They are rich in Asx, Glx and serine, but have few aromatic amino acids and no cystine or methionine. In calcium-buffered poly-acrylamide gels, it was observed that a reduction in the electrophoretic mobility of the spasmins was induced specifically by calcium (but not magnesium) at the same low concentiations as induce contraction. This indicates that the spasmins are calcium-binding proteins which may be involved directly in the calcium-induced contraction of the spasmoneme.