The green alga Pediastrum duplex forms colonies through asexual reproduction and has a unique life cycle. To elucidate the mechanisms that regulate the asexual reproductive cycle in P. duplex, we analyzed the effects of light on the processes and gene expression involved in each step of the asexual reproductive cycle, revealing light irradiation to be essential for increasing the number of colonies.
View Article and Find Full Text PDFPlant Signal Behav
December 2023
Photosynthetic organisms biosynthesize various carotenoids, a group of light-absorbing isoprenoid pigments that have key functions in photosynthesis, photoprotection, and phototaxis. Microalgae, in particular, contain diverse carotenoids and carotenoid biosynthetic pathways as a consequence of the various endosymbiotic events in their evolutionary history. Carotenoids such as astaxanthin, diadinoxanthin, and fucoxanthin are unique to algae.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
April 2023
Light-independent functions of carotenoids in photosynthetic organisms are poorly understood. Here, we investigated the growth properties of microalga, Euglena gracilis, under altered light and temperature using norflurazon-treated carotenoid-deficient cells and genetically modified strains, including nonphotosynthetic SM-ZK and colorless cl4. Norflurazon treatment decreased carotenoid and chlorophyll contents, causing cell bleaching.
View Article and Find Full Text PDFObjective: Few studies have reported on the impact of oxidative stress on the dental implant failure. The aim of this study was to investigate the impact of hyperglycemia-induced oxidative stress on dental implant osseointegration in diabetes mellitus (DM).
Methods: Acid-treated titanium implants were bilaterally placed in the maxillary alveolar ridge of streptozotocin-induced diabetic (DM group) and control rats after extraction of first molars.
Carotenoids are photosynthetic pigments and hydrophobic antioxidants that are necessary for the survival of photosynthetic organisms, including the microalga . In the present study, we identified an uncharacterized gene encoding the β-carotene synthetic enzyme lycopene cyclase (EgLCY) and discovered a relationship between EgLCY-mediated carotenoid synthesis and the reactive oxygen species (ROS) scavenging system ascorbate-glutathione cycle. The cDNA sequence was obtained homology searching transcriptome data.
View Article and Find Full Text PDFCell division of unicellular microalgae is a fascinating process of proliferation, at which whole organelles are regenerated and distributed to two new lives. We performed dynamic live cell imaging of using optical microscopy to elucidate the mechanisms involved in the regulation of the eyespot and flagellum during cell division and distribution of the organelles into the two daughter cells. Single cells of the wild type (WT) and colorless SM-ZK cells were confined in a microfluidic device, and the appearance of the eyespot (stigma) and emergent flagellum was tracked in sequential video-recorded images obtained by automatic cell tracking and focusing.
View Article and Find Full Text PDFGravitaxis is one of the most important issues in the growth of microalgae in the water column; it determines how easily cells receive sunlight with a comfortable intensity that is below the damaging threshold. We quantitatively investigated and analyzed the gravitaxis and cell multiplication of using vertically placed microchambers containing a single cell. A temporal change in gravitaxis and cell multiplication was observed after transferring the cells to fresh culture medium for 9 days.
View Article and Find Full Text PDFWe have previously found and characterized two pairs of enhancer elements, E1 and E2, in the type II collagen alpha 1 chain (COL2A1) gene. Subsequent studies have suggested that these enhancers function differently in the regulation of gene expression. For example, histone deacetylase 10 modifies only the E2 enhancer region to affect gene expression.
View Article and Find Full Text PDFEuglena gracilis exhibits photomovements in response to various light stimuli, such as phototactic and photophobic responses. Our recent study revealed that carotenoids in the eyespot apparatus are required for triggering phototaxis in this alga. However, the role of chloroplasts in eyespot formation is not understood.
View Article and Find Full Text PDFJ Photochem Photobiol B
August 2020
Hyaluronan (HA) has been shown to play crucial roles in the tumorigenicity of malignant tumors. Chondrosarcoma, particularly when low-grade, is characterized by the formation of an extracellular matrix (ECM) containing abundant HA, and its drug/radiation resistance has become a clinically relevant problem. This study aimed to evaluate the effects of a novel hyaluronidase, KIAA1199, on ECM formation as well as antitumor effects on chondrosarcoma.
View Article and Find Full Text PDFHyaline fibromatosis syndrome (HFS) is a rare autosomal recessive disorder characterized by hyaline fibrous depositions in the skin and internal organs. Contractured joints and gingival hypertrophy make airway management difficult in patients with HFS, while trunk deformities complicate surgical positioning. A 56-year-old woman with HFS underwent laparoscopic colectomy for sigmoid colon cancer.
View Article and Find Full Text PDFCarotenoids are the most universal and most widespread pigments in nature. They have played pivotal roles in the evolution of photosensing mechanisms in microbes and of vision in animals. Several groups of phytoflagellates developed a photoreceptive organelle called the eyespot apparatus (EA) consisting of two separable components: the eyespot, a cluster of carotenoid-rich globules that acts as a reflector device, and actual photoreceptors for photobehaviors.
View Article and Find Full Text PDFFor carotenogenesis, two biosynthetic pathways from phytoene to lycopene are known. Most bacteria and fungi require only phytoene desaturase (PDS, CrtI), whereas land plants require four enzymes: PDS (CrtP), ζ-carotene desaturase (ZDS, CrtQ), ζ-carotene isomerase (Z-ISO) and cis-carotene isomerase (CrtISO, CrtH). The gene encoding Z-ISO has been functionally identified in only two species, Arabidopsis thaliana and Zea mays, and has been little studied in other organisms.
View Article and Find Full Text PDFTo maintain normal function of cartilage tissue normally, the presence of a sufficient amount of type II collagen and aggrecan is essential, and their synthesis is tightly regulated. Therefore, understanding the mechanisms that control the expression of type II collagen and aggrecan would be useful for understanding gene expression changes in diseases such as osteoarthritis. Recently, we have identified two pairs of enhancer elements, termed E1 and E2 in the type II collagen gene and Ea and Eb in the aggrecan gene.
View Article and Find Full Text PDFSome carotenoids are found in the Euglena gracilis, including β-carotene, diadinoxanthin, diatoxanthins, and neoxanthin as the major species; however, the molecular mechanism underlying carotenoid biosynthesis in E. gracilis is not well understood. To clarify the pathway and regulation of carotenoid biosynthesis in this alga, we functionally characterized the cytochrome P450 (CYP)-type carotene hydroxylase gene EgCYP97H1.
View Article and Find Full Text PDFThe endometrium extracellular matrix (ECM) is essential for embryo implantation. Versican, a large chondroitin sulfate proteoglycan that binds hyaluronan and forms large ECM aggregates, can influence fundamental physiological phenomena, such as cell proliferation, adhesion and migration. The present study investigated the possible role of versican in human embryo implantation.
View Article and Find Full Text PDFCarotenoids participate in photosynthesis and photoprotection in oxygenic phototrophs. Euglena gracilis, a eukaryotic phytoflagellate, synthesizes several carotenoids: β-carotene, neoxanthin, diadinoxanthin and diatoxanthin. Temperature is one of the most striking external stimuli altering carotenoid production.
View Article and Find Full Text PDFHyaluronan (HA) has been shown to play crucial roles in the tumorigenicity of malignant tumors. Chondrosarcoma, particularly when low-grade, is characterized by the formation of an extracellular matrix (ECM) containing abundant HA, and its drug/radiation resistance has become a clinically relevant problem. This study aimed to evaluate the effects of an HA synthesis inhibitor, 4-methylumbelliferone (MU), on ECM formation as well as antitumor effects in chondrosarcoma.
View Article and Find Full Text PDFBackground: Photosynthetic organisms utilize carotenoids for photoprotection as well as light harvesting. Our previous study revealed that high-intensity light increases the expression of the gene for phytoene synthase (EgcrtB) in Euglena gracilis (a unicellular phytoflagellate), the encoded enzyme catalyzes the first committed step of the carotenoid biosynthesis pathway. To examine carotenoid synthesis of E.
View Article and Find Full Text PDFJ Clin Endocrinol Metab
November 2016
Context: Sampson's theory cannot explain why only some cycling women develop peritoneal endometriosis. Few studies have focused on the pelvic peritoneum, which receives regurgitated endometrial tissues. We hypothesized that molecular alterations in the peritoneum are involved in the development of peritoneal endometriosis and conducted a microarray analysis to compare macroscopically normal peritoneum sampled from women with peritoneal endometriosis (endometriotic peritoneum) and those without (non-endometriotic peritoneum).
View Article and Find Full Text PDFType II collagen is a major component of cartilage, which provide structural stiffness to the tissue. As a sufficient amount of type II collagen is critical for maintaining the biomechanical properties of cartilage, its expression is tightly regulated in chondrocytes. Therefore, it is essential to elucidate in detail the transcriptional mechanism that controls expression of type II collagen, in particular by two enhancer elements we recently discovered.
View Article and Find Full Text PDFBackground: Euglena gracilis, a unicellular phytoflagellate within Euglenida, has attracted much attention as a potential feedstock for renewable energy production. In outdoor open-pond cultivation for biofuel production, excess direct sunlight can inhibit photosynthesis in this alga and decrease its productivity. Carotenoids play important roles in light harvesting during photosynthesis and offer photoprotection for certain non-photosynthetic and photosynthetic organisms including cyanobacteria, algae, and higher plants.
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