Korea University

About: Korea University is a education organization based out in Seoul, South Korea. It is known for research contribution in the topics: Population & Catalysis. The organization has 39756 authors who have published 82424 publications receiving 1860927 citations. The organization is also known as: Bosung College & Bosung Professional College.

Arabidopsis ABCG14 is essential for the root-to-shoot translocation of cytokinin

Abstract: Cytokinins are phytohormones that induce cytokinesis and are essential for diverse developmental and physiological processes in plants. Cytokinins of the trans-zeatin type are mainly synthesized in root vasculature and transported to the shoot, where they regulate shoot growth. However, the mechanism of long-distance transport of cytokinin was hitherto unknown. Here, we report that the Arabidopsis ATP-binding cassette (ABC) transporter subfamily G14 (AtABCG14) is mainly expressed in roots and plays a major role in delivering cytokinins to the shoot. Loss of AtABCG14 expression resulted in severe shoot growth retardation, which was rescued by exogenous trans-zeatin application. Cytokinin content was decreased in the shoots of atabcg14 plants and increased in the roots, with consistent changes in the expression of cytokinin-responsive genes. Grafting of atabcg14 scions onto wild-type rootstocks restored shoot growth, whereas wild-type scions grafted onto atabcg14 rootstocks exhibited shoot growth retardation similar to that of atabcg14. Cytokinin concentrations in the xylem are reduced by ∼90% in the atabcg14 mutant. These results indicate that AtABCG14 is crucial for the translocation of cytokinin to the shoot. Our results provide molecular evidence for the long-distance transport of cytokinin and show that this transport is necessary for normal shoot development.

Clinical Significance of a High SARS-CoV-2 Viral Load in the Saliva.

Abstract: Background Patients with coronavirus disease 2019 (COVID-19) can unknowingly spread the virus to several people during the early subclinical period. Methods We evaluated the viral dynamics in various body fluid specimens, such as nasopharyngeal swab, oropharyngeal swab, saliva, sputum, and urine specimens, of two patients with COVID-19 from hospital day 1 to 9. Additional samples of the saliva were taken at 1 hour, 2 hours, and 4 hours after using a chlorhexidine mouthwash. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load was determined by real-time reverse transcriptase polymerase chain reaction (rRT-PCR). Results SARS-CoV-2 was detected from all the five specimens of both patients by rRT-PCR. The viral load was the highest in the nasopharynx (patient 1 = 8.41 log10 copies/mL; patient 2 = 7.49 log10 copies/mL), but it was also remarkably high in the saliva (patient 1 = 6.63 log10 copies/mL; patient 2 = 7.10 log10 copies/mL). SARS-CoV-2 was detected up to hospital day 6 (illness day 9 for patient 2) from the saliva of both patients. The viral load in the saliva decreased transiently for 2 hours after using the chlorhexidine mouthwash. Conclusion SARS-CoV-2 viral load was consistently high in the saliva; it was relatively higher than that in the oropharynx during the early stage of COVID-19. Chlorhexidine mouthwash was effective in reducing the SARS-CoV-2 viral load in the saliva for a short-term period.

Measurement of neutral mesons in p+p collisions at √s=200GeV and scaling properties of hadron production

Abstract: The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the invariant differential cross section for production of K-S(0), omega, eta', and phi mesons in p + p collisions at root s 200 GeV. Measurements of omega and phi production in different decay channels give consistent results. New results for the omega are in agreement with previously published data and extend the measured p(T) coverage. The spectral shapes of all hadron transverse momentum distributions measured by PHENIX are well described by a Tsallis distribution functional form with only two parameters, n and T, determining the high-p(T) and characterizing the low-p(T) regions of the spectra, respectively. The values of these parameters are very similar for all analyzed meson spectra, but with a lower parameter T extracted for protons. The integrated invariant cross sections calculated from the fitted distributions are found to be consistent with existing measurements and with statistical model predictions.