Quaternary structure of LOV-domain containing polypeptide of Arabidopsis FKF1 protein

AbstractFlavin-binding, Kelch repeat, F-box (FKF1) protein is a photoreceptor to regulate flowering of Arabidopsis. The protein has a light, oxygen and voltage (LOV)-sensing domain binding a flavin mononucleotide. The photo-activation of the domain is an indispensable step to initiate the cellular signaling for flowering. In the present study, a LOV-containing polypeptide of FKF1 was prepared by an overexpression system, and the quaternary structure of it was studied by size exclusion chromatography and small-angle X-ray scattering. The apparent molecular weight from chromatography suggested a globular trimeric or an anisotropic-shaped dimeric association of the polypeptide in solution. The scattering experiment demonstrated a dimeric association of the polypeptides with an elongated molecular shape displaying the radius of gyration of 27Å and the maximum dimension of 94Å. The molecular shape simulated from scattering profiles suggests an antiparallel association of the LOV domains in the dimer. Though the absorption spectrum of blue-light irradiated polypeptide was stable in the photoactivated state for a long period, the scattering profiles showed very small changes between the dark and light conditions. Based on the homologies in the amino-acid sequences and the scattering profiles, these results are discussed in connection with the structures and function of LOV domains of phototropin

CO₂-dependent migration and relocation of LCIB, a pyrenoid-peripheral protein in Chlamydomonas reinhardtii

葉緑体タンパク質が働く場所を変化させ光合成の能力を柔軟に維持する仕組みを発見. 京都大学プレスリリース. 2021-12-23.Most microalgae overcome the difficulty of acquiring inorganic carbon (Ci) in aquatic environments by inducing a CO₂-concentrating mechanism (CCM). In the green alga Chlamydomonas reinhardtii, two distinct photosynthetic acclimation states have been described under CO₂-limiting conditions (low-CO₂, LC, and very low-CO₂, VLC). LC-inducible protein B (LCIB), structurally characterized as carbonic anhydrase, localizes in the chloroplast stroma under CO₂-supplied and LC conditions. In VLC conditions, it migrates to aggregate around the pyrenoid, where the CO₂-fixing enzyme Rubisco is enriched. Although the physiological importance of LCIB localization changes in the chloroplast has been shown, factors necessary for the localization changes remain uncertain. Here, we examined the effect of pH, light availability, photosynthetic electron flow, and protein synthesis on the localization changes, along with measuring Ci concentrations. LCIB dispersed or localized in the basal region of the chloroplast stroma at 8.3–15 µM CO₂, whereas LCIB migrated toward the pyrenoid at 6.5 µM CO₂. Furthermore, LCIB relocated toward the pyrenoid at 2.6–3.4 µM CO₂, even in cells in the dark or treated with DCMU and cycloheximide in light. In contrast, in the mutant lacking CCM₁, a master regulator of CCM, LCIB remained dispersed even at 4.3 µM CO₂. Meanwhile, a simultaneous expression of LCIC, an interacting protein of LCIB, induced the localization of several speckled structures at the pyrenoid periphery. These results suggest that the localization changes of LCIB require LCIC and are controlled by CO₂ concentration with ∼7 µM as the boundary

3-Dimensional Classification and Visualization of Clouds Simulated by Cloud-Resolving Atmospheric General Circulation Model

Cloud-resolving atmospheric general circulation models using large scale supercomputers reproduce realistic behavior of atmospheric field on a global scale. To understand the simulation result for scientists, visualizing individual clouds and their physical characteristics is necessary. In this study, we propose a new feature extraction and classification method of simulated clouds based on their 3-dimensional shape and physical properties. The results of applying the proposed method show the clouds' distribution of a tropical cyclone during its generation, development and disappearance process, and the relation between cloud-forms and precipitation

The effect of omega-3 fatty acids on psychophysiological assessment for the secondary prevention of posttraumatic stress disorder: an open-label pilot study.

Our recent pilot study has shown that the supplementation of omega-3 fatty acids (fish oil) immediately after a traumatic event may be effective toward the secondary prevention of post-traumatic disorder (PTSD). To lay the groundwork for addressing the mechanism by which omega-3 fatty acids can prevent PTSD, we analyzed its psychophysiological data. The psychophysiological data included heart rate, skin conductance, and continuous blood pressure during patient subjection to startling tones and idiographic trauma-related cues. Of the 8 patients, 1 met the diagnostic criteria for PTSD. Compared to the seven patients without PTSD, one patient with PTSD showed relatively large reactivity to the startle tones. In contrast, this patient did not show large reactivity to the trauma-related cue during script-driven imagery. The combination of psychophysiological measurements in our randomized control trial should shed light on the underlying mechanisms by which omega-3 fatty acids can prevent PTSD

Differences in Attitudes and Practices of Cancer Pain Management between Medical Oncologists and Palliative Care Physicians

This study aimed to evaluate whether there are differences in the attitudes and practices of cancer pain manage-ment between medical oncologists and palliative care physicians. An online nationwide survey was used to collect responses from board-certified medical oncologists and palliative care physicians in Japan. The survey questionnaire comprised 30 questions. The differences in responses between medical oncologists and palliative care physicians were examined. Out of the 1,227 questionnaires sent, 522 (42.5%) were returned. After apply-ing the exclusion criteria, 445 questionnaires (medical oncologists: n = 283; palliative care physicians: n = 162) were retained for analysis. Among the questions about potential barriers to optimal cancer pain man-agement, both medical oncologists and palliative care physicians considered the reluctance of patients to take opioids due to fear of adverse effects as the greatest barrier. Significantly different ratings between medical oncologists and palliative care physicians were observed on 5 of the 8 questions in this area. Significantly differ-ent ratings were observed for all questions concerning pain specialists and their knowledge. For effective cancer pain management, it is important to account for differences in attitudes and practice between medical oncolo-gists and palliative care physicians

Concern over radiation exposure and psychological distress among rescue workers following the Great East Japan Earthquake

<p>Abstract</p> <p>Background</p> <p>On March 11, 2011, the Great East Japan Earthquake and tsunami that followed caused severe damage along Japans northeastern coastline and to the Fukushima Daiichi nuclear power plant. To date, there are few reports specifically examining psychological distress in rescue workers in Japan. Moreover, it is unclear to what extent concern over radiation exposure has caused psychological distress to such workers deployed in the disaster area.</p> <p>Methods</p> <p>One month after the disaster, 424 of 1816 (24%) disaster medical assistance team workers deployed to the disaster area were assessed. Concern over radiation exposure was evaluated by a single self-reported question. General psychological distress was assessed with the Kessler 6 scale (K6), depressive symptoms with the Center for Epidemiologic Studies Depression Scale (CES-D), fear and sense of helplessness with the Peritraumatic Distress Inventory (PDI), and posttraumatic stress symptoms with the Impact of Event Scale-Revised (IES-R).</p> <p>Results</p> <p>Radiation exposure was a concern for 39 (9.2%) respondents. Concern over radiation exposure was significantly associated with higher scores on the K6, CES-D, PDI, and IES-R. After controlling for age, occupation, disaster operation experience, duration of time spent watching earthquake news, and past history of psychiatric illness, these associations remained significant in men, but did not remain significant in women for the CES-D and PDI scores.</p> <p>Conclusion</p> <p>The findings suggest that concern over radiation exposure was strongly associated with psychological distress. Reliable, accurate information on radiation exposure might reduce deployment-related distress in disaster rescue workers.</p

Identification of the catalytic subunit of cAMP-dependent protein kinase from the photosynthetic flagellate, Euglena gracilis Z11The nucleotide sequence data reported in this paper will appear in the DDBJ/EMBL/GenBank nucleotide sequence databases with the accession number AB021126.

AbstractA gene named epk2 that encodes the amino acid sequence of a protein kinase was identified from the photosynthetic flagellate, Euglena gracilis Z. Homology search and phylogenetic analysis revealed that the deduced amino acid sequence of epk2 is most similar to that of the catalytic subunit of cAMP-dependent protein kinase (PKA). Northern blot analysis showed that Euglena cells express a 1.4-kb transcript of this gene. When the EPK2 protein was coexpressed with the rat regulatory subunit of PKA in cultured mammalian cells, these two proteins were coimmunoprecipitated. The association of EPK2 and the rat regulatory subunit of PKA was not detected in the cell lysate incubated with cAMP. EPK2 immunoprecipitated from the transfected cells phosphorylated Kemptide, a synthetic peptide substrate for PKA, and the phosphorylation was inhibited by PKI, a PKA-selective protein kinase inhibitor. These results indicate that EPK2 is a PKA homologue in the photosynthetic flagellate, and this is the first evidence for the occurrence of the PKA catalytic subunit in photosynthetic organisms