CAPRICE (CPC), a small, R3-type Myb-like protein, is a positive regulator of root hair development in Arabidopsis.Cell-to-cell movement of CPC is important for the differentiation of epidermal cells into trichoblasts (root hair cells). CPC is transported from atrichoblasts (hairless cells), where it is expressed, to trichoblasts, and generally accumulates in their nuclei. Using truncated versions of CPC fused to GFP, we identified a signal domain that is necessary and sufficient for CPC cell-to-cell movement. This domain includes the N-terminal region and a part of the Myb domain. Amino acid substitution experiments indicated that W76 and M78 in the Myb domain are critical for targeted transport, and that W76 is crucial for the nuclear accumulation of CPC:GFP. To evaluate the tissuespecificity of CPC movement, CPC:GFP was expressed in the stele using the SHR promoter and in trichoblasts using the EGL3 promoter. CPC:GFP was able to move from trichoblasts to atrichoblasts but could not exit from the stele, suggesting the involvement of tissue-specific regulatory factors in the intercellular movement of CPC. Analyses with a secretion inhibitor, Brefeldin A, and with an rhd3 mutant defective in the secretion process in root epidermis suggested that intercellular CPC movement is mediated through plasmodesmata. Furthermore, the fusion of CPC to tandem-GFPs defined the capability of CPC to increase the size exclusion limit of plasmodesmata.
The results of this study demonstrate that hyperglycemia inhibits human PDLSC proliferation and osteoblastic differentiation.
Microtubules assemble into several distinct arrays that play important roles in cell division and cell morphogenesis. To decipher the mechanisms that regulate the dynamics and organization of this versatile cytoskeletal component, it is essential to establish in vitro assays that use functional tubulin. Although plant tubulin has been purified previously from protoplasts by reversible taxol-induced polymerization, a simple and efficient purification method has yet to be developed. Here, we used a Tumor Overexpressed Gene (TOG) column, in which the tubulin-binding domains of a yeast (Saccharomyces cerevisiae) TOG homolog are immobilized on resin, to isolate functional plant tubulin. We found that several hundred micrograms of pure tubulin can readily be purified from cell suspension cultures of tobacco (Nicotiana tabacum) and Arabidopsis (Arabidopsis thaliana). The tubulin purified by the TOG column showed high assembly competence, partly because of low levels of polymerization-inhibitory phosphorylation of a-tubulin. Compared with porcine brain tubulin, Arabidopsis tubulin is highly dynamic in vitro at both the plus and minus ends, exhibiting faster shrinkage rates and more frequent catastrophe events, and exhibits frequent spontaneous nucleation. Furthermore, our study shows that an internal histidine tag in a-tubulin can be used to prepare particular isotypes and specifically engineered versions of a-tubulin. In contrast to previous studies of plant tubulin, our mass spectrometry and immunoblot analyses failed to detect posttranslational modification of the isolated Arabidopsis tubulin or detected only low levels of posttranslational modification. This novel technology can be used to prepare assembly-competent, highly dynamic pure tubulin from plant cell cultures.Microtubules (MTs) are important cytoskeletal polymers that are conserved in eukaryotic cells and are assembled from a-and b-tubulin heterodimers (Desai and Mitchison, 1997). In plants, MTs have important functions in essential cellular processes, such as cell division, and in cell morphogenesis. MTs in plant cells adopt several distinct higher order arrays and are remodeled in response to the cell cycle, developmental programs, and environmental cues (Hashimoto, 2015). Genetic, molecular, and cell biological approaches have been used to identify cellular factors that regulate the organization and dynamics of plant MTs. Considerable effort has been devoted to simulating the organization of cortical MT arrays by computational modeling.Cell-free in vitro studies are essential for the biochemical characterization of various MT regulators and for elucidating the mechanistic principles underlying the versatility of this dynamic polymer in cellular functions. The purification of sufficient amounts of assembly-competent tubulin is a prerequisite for these in vitro studies. Tubulin is traditionally purified from mammalian brains, since these tissues contain sufficiently high concentrations of tubulin to allow MT assembly in crude cell extracts. Polymerized MT...
Purpose of Review Artificial intelligence (AI) can make advanced inferences based on a large amount of data. The mainstream technologies of the AI boom in 2021 are machine learning (ML) and deep learning, which have made significant progress due to the increase in computational resources accompanied by the dramatic improvement in computer performance. In this review, we introduce AI/ML-based medical devices and prediction models regarding diabetes. Recent Findings In the field of diabetes, several AI-/ML-based medical devices and regarding automatic retinal screening, clinical diagnosis support, and patient self-management tool have already been approved by the US Food and Drug Administration. As for new-onset diabetes prediction using ML methods, its performance is not superior to conventional risk stratification models that use statistical approaches so far. Summary Despite the current situation, it is expected that the predictive performance of AI will soon be maximized by a large amount of organized data and abundant computational resources, which will contribute to a dramatic improvement in the accuracy of disease prediction models for diabetes.
The pharmacological profile of celecoxib (CAS 169590-42-5, SC-58635), a specific cyclooxygenase-2 (COX-2) inhibitor, was investigated. Celecoxib inhibited COX-2-mediated prostaglandin E2 (PGE2) production in human dermal fibroblasts (IC50 = 91 nmol/l), whereas it was a weak inhibitor of COX-1-mediated PGE2 production in human lymphoma cells (IC50 = 2800 nmol/l). In in vivo studies, the effects of celecoxib were compared with those of nonsteroidal anti-inflammatory drugs (NSAIDs) in acute rat models of hyperalgesia and pyrexia. Celecoxib abrogated carrageenan-induced hyperalgesia in the hind paw accompanied by a decrease in PGE2 content in paw exudates and cerebrospinal fluid in a dose-related manner, with an ED30 = 0.81 mg/kg. Its analgesic potency was comparable to those of NSAIDs. In lipopolysaccharide-induced pyrexia, the anti-pyretic potency of celecoxib was equal to that of NSAIDs. On the other hand, in a gastric toxicity study in rats, single oral administration of celecoxib had no effect on gastric mucosa or mucosal PGE2 content at doses up to 200 mg/kg. Additionally, celecoxib did not inhibit thromboxane B2 production of calcium ionophore-stimulated peripheral blood of rats or arachidonic acid-induced aggregation of human platelets. These findings suggest that celecoxib might be a safe and effective alternative to NSAIDs for clinical use.
In vitro assays revealed that COX-2 inhibitors with CA II inhibitory potency suppressed both differentiation and activity of osteoclasts, whereas that without the potency reduced only osteoclast differentiation. However, all COX-2 inhibitors similarly suppressed bone destruction in adjuvant-induced arthritic rats, indicating that suppression of osteoclast differentiation is more effective than that of osteoclast activity for the treatment.Introduction: Cyclooxygenase (COX)-2 and carbonic anhydrase II (CA II) are known to play important roles in the differentiation of osteoclasts and the activity of mature osteoclasts, respectively. Because several COX-2 selective agents were recently found to possess an inhibitory potency against CA II, this study compared the bone sparing effects of COX-2 selective agents with and without the CA II inhibitory potency. Materials and Methods: Osteoclast differentiation was determined by the mouse co-culture system of osteoblasts and bone marrow cells, and mature osteoclast activity was measured by the pit area on a dentine slice resorbed by osteoclasts generated and isolated from bone marrow cells. In vivo effects on arthritic bone destruction were determined by radiological and histological analyses of hind-paws of adjuvant-induced arthritic (AIA) rats. Results: CA II was expressed predominantly in mature osteoclasts, but not in the precursors. CA II activity was inhibited by sulfonamide-type COX-2 selective agents celecoxib and JTE-522 similarly to a CA II inhibitor acetazolamide, but not by a methylsulfone-type COX-2 inhibitor rofecoxib. In vitro assays clearly revealed that celecoxib and JTE-522 suppressed both differentiation and activity of osteoclasts, whereas rofecoxib and acetazolamide suppressed only osteoclast differentiation and activation, respectively. However, bone destruction in AIA rats was potently and similarly suppressed by all COX-2 selective agents whether with or without CA II inhibitory potency, although only moderately by acetazolamide. Conclusions: Suppression of osteoclast differentiation by COX-2 inhibition is more effective than suppression of mature osteoclast activity by CA II inhibition for the treatment of arthritic bone destruction.
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