Training cessation and subsequent retraining of a world-class female Olympic sailor after Tokyo 2020: A case study

Olympic sailing is a complex sport where sailors are required to predict and interpret weather conditions while facing high physical and physiological demands. While it is essential for sailors to develop physical and physiological capabilities toward major competition, monitoring training status following the competition is equally important to minimize the magnitude of detraining and facilitate retraining. Despite its long history in the modern Olympics, reports on world-class sailors' training status and performance characteristics across different periodization phases are currently lacking. This case study aimed to determine the influence of training cessation and subsequent retraining on performance parameters in a world-class female sailor. A 31-year old female sailor, seventh in the Women's Sailing 470 medal race in Tokyo 2020, completely stopped training for 4 weeks following the Olympics, and resumed low-intensity training for 3 weeks. Over these 7 weeks, 12.7 and 5.3% reductions were observed in 6 s peak cycling power output and jump height, respectively, with a 4.7% decrease in maximal aerobic power output. Seven weeks of training cessation-retraining period induced clear reductions in explosive power production capacities but less prominent decreases in aerobic capacity. The current findings are likely attributed to the sailor's training characteristics during the retraining period.This study was part of Functional Development Project for Resilient Athlete Support commissioned by Japan Sports Agency

Molecular response of Deinococcus radiodurans to simulated microgravity explored by proteometabolomic approach

Regarding future space exploration missions and long-term exposure experiments, a detailed investigation of all factors present in the outer space environment and their effects on organisms of all life kingdoms is advantageous. Influenced by the multiple factors of outer space, the extremophilic bacterium Deinococcus radiodurans has been long-termly exposed outside the international Space Station in frames of the tanpopo orbital mission. the study presented here aims to elucidate molecular key components in D. radiodurans, which are responsible for recognition and adaptation to simulated microgravity. D. radiodurans cultures were grown for two days on plates in a fast-rotating 2-D clinostat to minimize sedimentation, thus simulating reduced gravity conditions. Subsequently, metabolites and proteins were extracted and measured with mass spectrometry-based techniques. our results emphasize the importance of certain signal transducer proteins, which showed higher abundances in cells grown under reduced gravity. these proteins activate a cellular signal cascade, which leads to differences in gene expressions. Proteins involved in stress response, repair mechanisms and proteins connected to the extracellular milieu and the cell envelope showed an increased abundance under simulated microgravity. focusing on the expression of these proteins might present a strategy of cells to adapt to microgravity conditions

The 1988-1989 explosive eruption of Tokachi-dake, central Hokkaido, Its sequence and mode

On December 16, 1988, after 26 years of dormancy since the last eruption in 1962, Tokachi-dake began to erupt from the 62-II crater. The eruption started with phreatic explosions. Then, on December 19, the activity changed into phreatomagmatic explosions of Vulcanian type and continued intermittently until March 5, 1989. Although the composition of the essential ejecta, mafic andesite, is similar to those of 1926 and 1962 eruptions, the mode of the present eruption is considerably diffrent The present eruption consists of a series of 23 discrete cannon-like explosions, being frequently accompanied with small-scale pyrcclastic surges and flows. The total volume of ejecta amounts to approximately 6×105 m3, of which about 20% is essential ejecta. A complete sequence of events was compiled and distribution maps of the ash-fall, ballistic blocks, and pyroclastic surges and flows were drawn for each of the larger eruptions. The pyrrolastic surges and flows of the present eruption were small scale, low temperature pyroclastic flows, rich in accessory clasts and unaccompanied by sector collapse. Therefore, the sudden melting of snow causing disastrous mudflows, as in the case of the 1926 eruption, fortunately did not occur

Ablation of the Ccr2 gene exacerbates polyarthritis in interleukin-1 receptor antagonist-deficient mice

金沢大学がん研究所Objective The pathogenesis of rheumatoid arthritis (RA) involves cytokines and chemokines. Given the role of intraarticular macrophage infiltration in RA, this study was undertaken to address the pathogenic role of CCR2, a chemokine receptor that is abundantly expressed by macrophages, in Il1rn-deficient mice, a mouse model of RA. Methods Il1rn-deficient and Il1rn and Ccr2-double-deficient mice were subjected to clinical assessment of arthritis and histologic examination. Bone mineral density was measured with computed tomography. The types of cells infiltrating joints were determined by immunohistochemical analysis and flow cytometric analysis. Osteoclasts in joints were quantified after tartrate-resistant acid phosphatase staining. Cytokine and chemokine levels were measured by enzyme-linked immunosorbent assay and multiplex suspension array assay. The expression patterns of chemokines and osteoclastogenic factors were determined by double-color immunofluorescence analysis. Anti-mouse CXCR2 antibody was injected into Il1rn and Ccr2-double-deficient mice for blocking experiments. Results Ablation of the Ccr2 gene actually exacerbated arthritis and intraarticular osteoclastogenesis, while it enhanced intraarticular neutrophil but not macrophage accumulation in Il1rn-deficient mice. Infiltrated neutrophils expressed the osteoclastogenic factors RANKL and ADAM-8, thereby augmenting intraarticular osteoclastogenesis in Il1rn and Ccr2-double-deficient mice. Moreover, the double-deficient mice exhibited enhanced expression of the neutrophilic chemokines keratinocyte chemoattractant and macrophage inflammatory protein 2 (MIP-2), compared with Il1rn-deficient mice. Finally, neutralizing antibodies to CXCR2, the receptor for keratinocyte chemoattractant and MIP-2, dramatically attenuated arthritis in Il1rn and Ccr2-double-deficient mice. Conclusion Our findings indicate that CCR2-mediated signals can modulate arthritis in Il1rn-deficient mice by negatively regulating neutrophil infiltration. © 2011 by the American College of Rheumatology

SICA-mediated cytoadhesion of Plasmodium knowlesi-infected red blood cells to human umbilical vein endothelial cells

Zoonotic malaria due to Plasmodium knowlesi infection in Southeast Asia is sometimes life-threatening. Post-mortem examination of human knowlesi malaria cases showed sequestration of P. knowlesi-infected red blood cells (iRBCs) in blood vessels, which has been proposed to be linked to disease severity. This sequestration is likely mediated by the cytoadhesion of parasite-iRBCs to vascular endothelial cells; however, the responsible parasite ligands remain undetermined. This study selected P. knowlesi lines with increased iRBC cytoadhesion activity by repeated panning against human umbilical vein endothelial cells (HUVECs). Transcriptome analysis revealed that the transcript level of one gene, encoding a Schizont Infected Cell Agglutination (SICA) protein, herein termed SICA-HUVEC, was more than 100-fold increased after the panning. Transcripts of other P. knowlesi proteins were also significantly increased, such as PIR proteins exported to the iRBC cytosol, suggesting their potential role in increasing cytoadhesion activity. Transgenic P. knowlesi parasites expressing Myc-fused SICA-HUVEC increased cytoadhesion activity following infection of monkey as well as human RBCs, confirming that SICA-HUVEC conveys activity to bind to HUVECs

Molecular response of Deinococcus radiodurans exposed to vacuum conditions of Low Earth Orbit

The polyextremophile, gram-positive bacterium Deinococcus radiodurans is able to withstand harsh conditions of real and simulated outer space environment, e.g., extreme temperature fluctuations, desiccation, UV radiation, and ionizing radiation. A long-term space exposure of D. radiodurans has been performed in exposure experiments at low Earth orbit in frames of the Tanpopo orbital mission aiming to investigate the possibility of interplanetary transfer of life. Although it is important to analyse the impact of space environmental factors simultaneously, it is also crucial to investigate these factors separately under controlled conditions in order to decipher fundamental response mechanisms involved

Proteomic and Metabolomic Profiling of Deinococcus radiodurans Recovering After Exposure to Simulated Low Earth Orbit Vacuum Conditions

The polyextremophile, gram-positive bacterium Deinococcus radiodurans can withstand harsh conditions of real and simulated outer space environment, e.g., UV and ionizing radiation. A long-term space exposure of D. radiodurans has been performed in Low Earth Orbit (LEO) in frames of the Tanpopo orbital mission aiming to investigate the possibility of interplanetary life transfer. Space vacuum (10-4–10-7 Pa) is a harmful factor, which induces dehydration and affects microbial integrity, severely damaging cellular components: lipids, carbohydrates, proteins, and nucleic acids. However, the molecular strategies by which microorganisms protect their integrity on molecular and cellular levels against vacuum damage are not yet understood. In a simulation experiment, we exposed dried D. radiodurans cells to vacuum (10-4–10-7 Pa), which resembles vacuum pressure present outside the International Space Station in LEO. After 90 days of high vacuum exposure, survival of D. radiodurans cells was 2.5-fold lower compared to control cells. To trigger molecular repair mechanisms, vacuum exposed cells of D. radiodurans were recovered in complex medium for 3 and 6 h. The combined approach of analyzing primary metabolites and proteins revealed important molecular activities during early recovery after vacuum exposure. In total, 1939 proteins covering 63% of D. radiodurans annotated protein sequences were detected. Proteases, tRNA ligases, reactive oxygen species (ROS) scavenging proteins, nucleic acid repair proteins, TCA cycle proteins, and S-layer proteins are highly abundant after vacuum exposure. The overall abundance of amino acids and TCA cycle intermediates is reduced during the recovery phase of D. radiodurans as they are needed as carbon source. Furthermore, vacuum exposure induces an upregulation of Type III histidine kinases, which trigger the expression of S-layer related proteins. Along with the highly abundant transcriptional regulator of FNR/CRP family, specific histidine kinases might be involved in the regulation of vacuum stress response. After repair processes are finished, D. radiodurans switches off the connected repair machinery and focuses on proliferation. Combined comparative analysis of alterations in the proteome and metabolome helps to identify molecular key players in the stress response of D. radiodurans, thus elucidating the mechanisms behind its extraordinary regenerative abilities and enabling this microorganism to withstand vacuum stress