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Tissue Culture System (tissue + culture_system)
Selected AbstractsPhysiological functions of hemocytes newly emerged from the cultured hematopoietic organs in the silkworm, Bombyx moriINSECT SCIENCE, Issue 1 2010Cheng-Long Wang Abstract, Cellular immunity is a very important part of insect innate immunity. It is not clear if hemocytes entering the hemolymph require a maturation process to become competent. The establishment of a tissue culture system for the insect hematopoietic organs would enable physiological function assays with hemocytes newly emerged from hematopoietic organs. To this end, we established a hematopoietic organ culture system for the purebred silkworm pnd pS and then studied the physiological functions of the newly emerged hemocytes. We found that Grace's medium supplemented with 10% heated silkworm larval plasma was better for culturing the hematopoietic organs of pnd pS. Newly emerged hemocytes phagocytosed propidium iodide-labeled bacteria and encapsulated the Iml-2 coated nickel beads as well as pupal tissue debris. This culture system is therefore capable of generating physiologically functional hemocytes. These hemocytes can be used to study the mechanisms of the hemocyte immune response among others. [source] Stress-induced somatic embryogenesis in vegetative tissues of Arabidopsis thalianaTHE PLANT JOURNAL, Issue 1 2003Miho Ikeda-Iwai Summary Somatic embryogenesis is an obvious experimental evidence of totipotency, and is used as a model system for studying the mechanisms of de-differentiation and re-differentiation of plant cells. Although Arabidopsis is widely used as a model plant for genetic and molecular biological studies, there is no available tissue culture system for inducing somatic embryogenesis from somatic cells in this plant. We established a new tissue culture system using stress treatment to induce somatic embryogenesis in Arabidopsis. In this system, stress treatment induced formation of somatic embryos from shoot-apical-tip and floral-bud explants. The somatic embryos grew into young plantlets with normal morphology, including cotyledons, hypocotyls, and roots, and some embryo-specific genes (ABI3 and FUS3) were expressed in these embryos. Several stresses (osmotic, heavy metal ion, and dehydration stress) induced somatic embryogenesis, but the optimum stress treatment differed between different stressors. When we used mannitol to cause osmotic stress, the optimal conditions for somatic embryogenesis were 6,9 h of culture on solid B5 medium containing 0.7 m mannitol, after which the explants were transferred to B5 medium containing 2,4-dichlorophenoxyacetic acid (2,4-D, 4.5 µm), but no mannitol. Using this tissue culture system, we induced somatic embryogenesis in three major ecotypes of Arabidopsis thaliana, Ws, Col, and Ler. [source] An ecdysteroid-inducible insulin-like growth factor-like peptide regulates adult development of the silkmoth Bombyx moriFEBS JOURNAL, Issue 5 2009Naoki Okamoto Insulin-like growth factors (IGFs) play essential roles in fetal and postnatal growth and development of mammals. They are secreted by a wide variety of tissues, with the liver being the major source of circulating IGFs, and regulate cell growth, differentiation and survival. IGFs share some biological activities with insulin but are secreted in distinct physiological and developmental contexts, having specific functions. Although recent analyses of invertebrate genomes have revealed the presence of multiple insulin family peptide genes in each genome, little is known about functional diversification of the gene products. Here we show that a novel insulin family peptide of the silkmoth Bombyx mori, which was purified and sequenced from the hemolymph, is more like IGFs than like insulin, in contrast to bombyxins, which are previously identified insulin-like peptides in B. mori. Expression analysis reveals that this IGF-like peptide is predominantly produced by the fat body, a functional equivalent of the vertebrate liver and adipocytes, and is massively released during pupa,adult development. Studies using in vitro tissue culture systems show that secretion of the peptide is stimulated by ecdysteroid and that the secreted peptide promotes the growth of adult-specific tissues. These observations suggest that this peptide is a Bombyx counterpart of vertebrate IGFs and that functionally IGF-like peptides may be more ubiquitous in the animal kingdom than previously thought. Our results also suggest that the known effects of ecdysteroid on insect adult development may be in part mediated by IGF-like peptides. [source] Properties of the hepatitis C virus core protein: a structural protein that modulates cellular processesJOURNAL OF VIRAL HEPATITIS, Issue 1 2000McLauchlan The core protein of hepatitis C virus (HCV) is believed to form the capsid shell of virus particles. Maturation of the protein is achieved through cleavage by host cell proteases to give a product of 21 000 MW, which is found in tissue culture systems and sera from infected individuals. However, efficient propagation of the virus is not possible at present in tissue culture. Hence, studies have focused on the properties of the core protein and its possible role in pathologies associated with HCV infection. This review describes key features of the polypeptide and the status of current knowledge on its ability to influence several cellular processes. [source] | ||||||||||