Search results for "Embryonic Structure"
showing 10 items of 624 documents
The expression of an immune-related phenoloxidase gene is modulated inCiona intestinalisovary, test cells, embryos and larva
2015
Two distinct Ciona intestinalis phenoloxidases (CinPO1, 2) had previously been cloned and sequenced. The CinPO2 is involved in innate immunity and is expressed by inflammatory hemocytes that populate the tunic and pharynx vessels as a response to LPS inoculation. In situ hybridization and immunohistochemistry assays on histological section, showed that the expression of this gene and the produced protein are shared with oogenesis, embryogenesis and larval morphogenesis. Intriguingly, upregulation of gene transcription was found in the test cell layer that envelopes the ovary follicle, ovulated egg, and gastrula, as well as it was modulated in the zygotic nucleus of outer balstomers of 32-ce…
An Inhibitor of Cytochrome Oxidase Activity in the Sea Urchin Egg
1959
PREVIOUS work in this laboratory1,2 has demonstrated the presence of a highly active cytochrome oxidase in the isolated mitochondria of unfertilized sea urchin eggs. This activity is only 25 per cent lower than that of the mitochondria of the newly fertilized egg and up to the blastula stage2. No cytochrome oxidase activity has been found other than in the mitochondria1,3. On the other hand, it is known that the oxygen consumption of the unfertilized sea urchin egg is quite low; fertilization restores a normal respiratory level which increases continuously during the early development (for a discussion, see ref. 4). The suggestion was then made2 that in the unfertilized egg an extra-mitocho…
Different integrins mediate cell spreading, haptotaxis and lateral migration of HaCaT keratinocytes on fibronectin
2000
Collaborative role of various fibronectin-binding integrins (alpha5beta1, alphavbeta1 and alphavbeta6) as mediators of cell adhesion and migration on fibronectin was studied using cultured HaCaT keratinocytes. This cell line spontaneously expressed all three fibronectin-binding integrins. In addition, the expression of alphavbeta6 integrin was strongly and specifically upregulated by transforming growth factor-beta1 (TGFbeta1) whereas the amount of other integrins remained practically unchanged on the cell surface. Adhesion, spreading and motility of HaCaT keratinocytes on fibronectin were promoted by TGFbeta1. Based on antibody blocking experiments, both untreated and TGFbeta1-treated HaCa…
Local administration of antisense phosphorothioate oligonucleotides to the c-kit ligand, stem cell factor, suppresses airway inflammation and IL-4 pr…
2001
Abstract Background: The c-kit ligand, stem cell factor (SCF), is an important activating and chemotactic factor for both mast cells and eosinophils. These cells are known to play a fundamental role in the pathogenesis of asthma. Objective: Our goal was to analyze the functional role of SCF in the pathogenesis of asthma. Methods: The expression of SCF was targeted in fibroblasts, epithelial cells, and locally in a murine model of asthma in mice induced by ovalbumin sensitization with an antisense DNA strategy. Results: We could suppress SCF expression in NIH 3T3 fibroblasts and SP1 epithelial cells by a specific antisense phosphorothioate oligonucleotide overlapping the translation start si…
Heat-stable antigen is expressed by murine keratinocytes and delivers costimulatory signals in T-cell activation.
1995
Heat-stable antigen (HSA), expressed by various antigen-presenting cells (APC), has been described as a costimulatory molecule for CD4+ T cells. Recently, we observed that HSA also serves as an important costimulatory molecule on epidermal Langerhans cells (LC). During these studies, low levels of HSA staining were also detected on normal murine keratinocytes (KC). To investigate whether HSA also is involved in T-cell activation by KC, normal murine KC or the spontaneously transformed KC cell-line PAM 212 were treated with PDB or PMA to induce HSA-expression. FACS analyses showed induction of HSA expression on normal murine KC, as well as PAM 212 cells. In functional assays PDB or PMA-treat…
LS104, a Novel Kinase Inhibitor, Induces Apoptosis, Synergizes with Cytostatic Drugs and Is Targeting the Receptor Tyrosine Kinase FLT3.
2005
Abstract Fms-like tyrosine kinase 3 (FLT3), a member of the class III tyrosine kinase receptor family, is expressed in up to 90% of acute myeloid leukemia (AML). Activating mutations like internal tandem duplication (ITD) of the juxtamembrane domain and kinase domain point mutations are found in approximately 35% of AML-cases and are considered to represent an attractive therapeutic target. In this study, we report that the novel hydroxystyryl-acrylonitrile compound LS104 induces potent cytotoxic effects in FLT3 ITD-positive leukemic cells. As a cellular model to investigate FLT3-ITD specific effects we used 32D myeloid cells stably transfected with FLT3-ITD and wt-FLT3, respectively. In MT…
Microelectrode Measurements of Oxygen Tension Distributions in Multicellular Spheroids Cultured in Spinner Flasks
1984
Since multicellular spheroids were introduced into cancer research by Sutherland et al. (1970, 1971), they have been widely used for studying the susceptibility of cancer cells to various treatment modalities. Many of these investigations provided evidence for a major role of oxygen in controlling the metabolic and cell cycle state of the tumor cells, thus modifying the responsiveness of the cells to therapy. Several investigators have measured O2 tension (PO2) distributions in spheroids with O2-sensitive microelectrodes (Carlsson et al. 1979; Kaufman et al. 1981; Mueller-Klieser and Sutherland 1982a, b, 1983; Mueller-Klieser et al. 1983). The measurements produced PO2 values that varied co…
Potential predation pressure of littoral mysids on herring (Clupea harengus membras L.) eggs and yolk-sac larvae
2008
The predation potential of littoral mysid shrimps (Mysidacea) on Baltic herring (Clupea harengus membras L.) eggs and yolk-sac larvae was studied experimentally. The results showed that littoral mysids feed actively on both eggs and yolk-sac larvae. It was shown that Neomysis integer preys on eggs, which are not attached to the substrate. Alternative food (yolk-sac larvae or zooplankton) did not decrease feeding rate on eggs. Only gravel as a bottom material lowered the ingestion rate to nearly zero. The largest of the mysid species Praunus flexuosus ate yolk-sac larvae more than other mysids and most efficiently. Mysids switched to feed on eggs when larvae and eggs were offered simultaneou…
Effects of Tributyltin(IV) Chloride Exposure on Larvae ofCiona intestinalis (Urochordata): An Ultrastructural Study
1996
The effects of tributyltin(IV) chloride (TBT chloride) have been tested on embryos of the ascidian Ciona intestinalis, at two different stages of development: (1) before hatching (coiled larval stage) and (2) 2 h after hatching (swimming larval stage). In vivo observations carried out with a light microscope showed that embryos at the coiled larval stage did not hatch following exposure to TBT chloride. Severe anomalies in the swimming larva, mainly concerning the morphology of the tail, which appeared twisted and squatter than in the controls, were observed. Such anomalies were also found at a functional level, i.e. contractile movements were poor so that the larvae appeared motionless. Ul…
HSP27 controls GATA-1 protein level during erythroid cell differentiation.
2010
AbstractHeat shock protein 27 (HSP27) is a chaperone whose cellular expression increases in response to various stresses and protects the cell either by inhibiting apoptotic cell death or by promoting the ubiquitination and proteasomal degradation of specific proteins. Here, we show that globin transcription factor 1 (GATA-1) is a client protein of HSP27. In 2 models of erythroid differentiation; that is, in the human erythroleukemia cell line, K562 induced to differentiate into erythroid cells on hemin exposure and CD34+ human cells ex vivo driven to erythroid differentiation in liquid culture, depletion of HSP27 provokes an accumulation of GATA-1 and impairs terminal maturation. More spec…