In angiosperms, cyclic electron transport (CET) around photosystem I (PSI) consists of two pathways, depending on PGR5/PGRL1 proteins and the chloroplast NDH complex. In single mutants defective in ...chloroplast NDH, photosynthetic electron transport is only slightly affected at low light intensity, but in double mutants impaired in both CET pathways photosynthesis and plant growth are severely affected. The question is whether this strong mutant phenotype observed in double mutants can be simply explained by the additive effect of defects in both CET pathways. In this study, we used the weak mutant allele of pgr5-2 for the background of double mutants to avoid possible problems caused by the secondary effects due to the strong mutant phenotype. In two double mutants, crr2-2 pgr5-2 and ndhs-1 pgr5-2, the plant growth was unaffected and linear electron transport was only slightly affected. However, NPQ induction was more severely impaired in the double mutants than in the pgr5-2 single mutant. A similar trend was observed in the size of the proton motive force. Despite the slight reduction in photosystem II parameters, PSI parameters were severely affected in the pgr5-2 single mutant, the phenotype that was further enhanced by adding the NDH defects. Despite the lack of ∆pH-dependent regulation at the cytochrome b6f complex (donor-side regulation of PSI), the plastoquinone pool was more reduced in the double mutants than in the pgr5-2 single mutants. This phenotype suggests that both PGR5/PGRL1- and NDH-dependent CET contribute to supply sufficient acceptors from PSI by balancing the ATP/NADPH production ratio.
•In the background of the weak allele of pgr5-2, the NDH defects reduced the size of NPQ and proton motive force in the absence of the growth defect•Despite the slight effect on PSII, PSI yield was dramatically reduced in pgr5-2 and the phenotype was enhanced by adding the NDH defects•The induction of ∆pH-dependent control of the cytochrome b6f complex was severely impaired in the double mutants•Despite the lack of donor-side regulation, the plastoquinone pool was reduced in the double mutants, suggesting the acceptor-limitation from PSI
Portable devices for home sleep apnea testing are often limited by their inability to discriminate sleep/wake status, possibly resulting in underestimations. Tracheal sound (TS), which can be ...visualized as a spectrogram, carries information about apnea/hypopnea and sleep/wake status. We hypothesized that image analysis of all-night TS recordings by a deep neural network (DNN) would be capable of detecting breathing events and classifying sleep/wake status. The aim of this study is to develop a DNN-based system for sleep apnea testing and validate it using a large sampling of polysomnography (PSG) data.
PSG examinations for the evaluation of sleep-disordered breathing (SDB) were performed for 1,852 patients: 1,548 PSG records were used to develop the system, and the remaining 304 records were used for validation. TS spectrogram images were obtained every 60 seconds and labeled with the PSG scoring results (breathing event and sleep/wake status), then introduced to DNN learning. Two different DNNs were trained for breathing status and sleep/wake status, respectively.
A DNN with convolutional layers showed the best performance for discriminating breathing status. The same DNN structure was trained for sleep/wake discrimination. In the validation study, the DNN analysis was capable of discriminating the sleep/wake status with reasonable accuracy. The diagnostic sensitivity, specificity, and area under the receiver operating characteristic curves for diagnosis of SDB with apnea-hypopnea index of > 5, 15, and 30 were 0.98, 0.76, and 0.99; 0.97, 0.90, and 0.99; and 0.92, 0.94, and 0.98, respectively.
The developed system using the TS DNN analysis has a good performance for SDB testing.
Nakano H, Furukawa T, Tanigawa T. Tracheal sound analysis using a deep neural network to detect sleep apnea. J Clin Sleep Med. 2019;15(8): 1125-1133.
Rice (Oryza sativa L.) ratooning has attracted attention due to its higher yield potential compared with conventional methods. Here, field experiments were conducted in southwestern Japan in 2019 and ...2020 to determine the effects of cultivar (‘Takanari’, an indica cultivar, and ‘Koshihikari’, a japonica cultivar) and harvest time of the first crop (early and late) on the grain yields of the first and second crops in rice ratooning. For Koshihikari in 2019, grain yield of the second crop did not differ between harvest times. However, Takanari produced a lower grain yield at late harvest. Takanari had fewer spikelets, fewer filled spikelets, and a lower 1,000‐grain weight at late harvest. However, for Takanari in 2020, grain yield did not differ between harvest times. In 2019, the stubble nonstructural carbohydrate (NSC) content did not increase from early to late harvest, whereas the stubble leaf area index (LAI) decreased between harvest times; this difference was more apparent in Takanari than in Koshihikari. Contrastingly, in 2020, the NSC content increased from early to late harvest, but the stubble LAI did not differ between harvest times. Thus, the lower grain yield of late‐harvested Takanari in 2019 might be attributed to the lower stubble LAI resulting in fewer spikelets. In contrast, the maintained grain yield from early to late harvest in 2020 might be attributed to the maintenance of spikelet numbers via the higher stubble NSC content. Therefore, the sufficient stubble LAI and NSC could be essential for improving grain yield of the second crop.
Core Ideas
Takanari produced a lower grain yield of the second crop at late harvest in 2019.
Takanari had fewer spikelets at late harvest due to the lower stubble leaf area index (LAI) in 2019.
For Takanari, grain yield of the second crop did not differ between harvest times in 2020.
Takanari did not have fewer spikelets at late harvest due to the higher nonstructural carbohydrate (NSC) content in 2020.
The sufficient stubble LAI and NSC could be essential for improving grain yield.
The aim of this study was to use small unmanned aerial vehicles (UAVs) for determining high-resolution normalized difference vegetation index (NDVI) values. Subsequently, these results were used to ...assess their correlations with fertilizer application levels and the yields of rice and wheat crops. For multispectral sensing, we flew two types of small UAVs (DJI Phantom 4 and DJI Phantom 4 Pro)—each equipped with a compact multispectral sensor (Parrot Sequoia). The information collected was composed of numerous RGB orthomosaic images as well as reflectance maps with spatial resolution greater than a ground sampling distance of 10.5 cm. From 223 UAV flight campaigns over 120 fields with a total area coverage of 77.48 ha, we determined that the highest efficiency for the UAV-based remote sensing measurement was approximately 19.8 ha per 10 min while flying 100 m above ground level. During image processing, we developed and used a batch image alignment algorithm—a program written in Python language–to calculate the NDVI values in experimental plots or fields in a batch of NDVI index maps. The color NDVI distribution maps of wide rice fields identified differences in stages of ripening and lodging-injury areas, which accorded with practical crop growth status from aboveground observation. For direct-seeded rice, variation in the grain yield was most closely related to that in the NDVI at the early reproductive and late ripening stages. For wheat, the NDVI values were highly correlated with the yield ( R 2 = 0.601–0.809) from the middle reproductive to the early ripening stages. Furthermore, using the NDVI values, it was possible to differentiate the levels of fertilizer application for both rice and wheat. These results indicate that the small UAV-derived NDVI values are effective for predicting yield and detecting fertilizer application levels during rice and wheat production.
Rice (Oryza sativa L.) ratooning has attracted attention due to its higher yield potential. In the present study, a field experiment on rice ratooning using two rice genotypes, near isogenic line ...(NIL)‐GN1ATakanari and Koshihikari, was conducted in 2019 and 2020 in southwestern Japan to obtain direct evidence for the role of stubble nonstructural carbohydrate (NSC) concentration and/or content per unit area on grain yield of the second crop and to determine the effectiveness of a gene producing more spikelets. NIL‐GN1ATakanari is a near isogenic line carrying an allele of GN1A, which is a gene regulating the number of spikelets per unit area derived from an indica cultivar Takanari in the genetic background of a japonica cultivar Koshihikari, and it can produce more spikelets than Koshihikari. NIL‐GN1ATakanari did not produce a higher grain yield of the first crop than Koshihikari in both years because NIL‐GN1ATakanari had more spikelets m−2 but fewer filled spikelets and a lower grain weight. NIL‐GN1ATakanari produced a lower grain yield of the second crop than Koshihikari because NIL‐GN1ATakanari had fewer spikelets m−2 due to the fewer panicles. Also, NIL‐GN1ATakanari had a lower NSC content than Koshihikari due to the lower leaf sheath plus stem weight in the stubble in 2019. Thus, the lower grain yield in the second crop of NIL‐GN1ATakanari may result from the lower NSC content in the stubble. Additionally, the ability to produce more spikelets per unit area of NIL‐GN1ATakanari was not demonstrated in ratoon crop under the condition of low NSC content in the stubble.
Core Ideas
NIL‐GN1ATakanari produced a lower grain yield of the second crop than Koshihikari.
NIL‐GN1ATakanari had fewer spikelets m−2 of the second crop than Koshihikari.
NIL‐GN1ATakanari had a lower NSC content in the stubble than Koshihikari.
The lower grain yield of NIL‐GN1ATakanari may result from the lower NSC content in the stubble.
Rice (Oryza sativa L.) ratooninghas recently attracted attention due to its higher yield potential compared with that of conventional methods. Field experiments were conducted in southwestern Japan ...in 2019 and 2020 to determine the effect of rice type (Hokuriku 193 and high‐yielding line HYL) and stubble leaf treatment (clipping and control) on the grain yields of the first and second crops in rice ratooning. In 2019, both rice types produced lower grain yields of the second crop in the leaf clipping treatment than the control treatment due to the lower spikelet number m−2. Therefore, increasing the leaf area index (LAI) in the stubble may improve the grain yield of the second crop by increasing the spikelet number per area. In 2020, HYL produced a lower grain yield of the second crop in the leaf clipping treatment than the control treatment due to the lower spikelet number m−2. However, the grain yields of Hokuriku 193 did not differ between the two leaf clipping treatments. Although the nonstructural carbohydrate (NSC) content in the stubble did not differ between the two rice types in 2019, Hokuriku 193 had a higher NSC content than HYL in 2020 due to the lower spikelet number m−2 and lower percentage of filled spikelets of the first crop. These results suggest that the stubble leaf blade contribution may be reduced when the NSC content is high as the leaf blades may compensate for the lack of NSC content when the NSC content is low.
Core Ideas
Stubble leaf blades contribute to the spikelet number per area.
Stubble leaf blades compensate for low stubble nonstructural carbohydrate content.
Early maturing cultivars are recommended to avoid lower grain filling.
Low specific volumes and high firming rates are major issues in the preparation of gluten-free rice bread. Herein, we discovered that flour acquired from rice grains ripened under lower temperatures ...improved the specific volume and firming rate of the resultant gluten- and additive-free rice bread. Two cultivars with different amylose contents were grown during three growing seasons (early, normal, and late) over two years (2016 and 2017). The temperatures during grain filling ranged from 22.0 to 30.1 °C, and the small differences observed between the average particle sizes and the damaged-starch contents of the samples indicated that their grain-filling temperatures had minimal influence on their flour properties. There were significant negative correlations between the grain-filling temperatures and the amylose contents or ratios of short amylopectin chains of the rice-flour samples. The bread loaf volumes were influenced by their amylose contents, not by their amylopectin structures, and correlated negatively with the grain-filling temperatures. Inversely, the bread-firming rates during storage were influenced predominantly by their amylopectin structures, and positively correlated with the grain-filling temperatures. These results indicate that rice grains ripened under lower temperatures are desirable, and that the grain-filling temperature can be an indicator of the firming of gluten-free rice bread.
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•Low-temperature ripened rice bread has high loaf volume due to amylose content.•They have slower firming through high ratio of shorter amylopectin chains.•Temperature during grain filling and gelatinization are bread firming indicators.
The primary goal of ligand-based virtual screening is to identify active compounds consisting of a core scaffold that is not found in the current active compound pool. Scaffold hopping is the term ...used for this purpose. In the present study, topological representations of pharmacophore features on chemical graphs were investigated for scaffold hopping. Pharmacophore graphs (PhGs), which consist of pharmacophore features as nodes and their topological distances as edges, were used as a representation of important information on compounds being active. We investigated ranking methods for prioritizing PhGs for scaffold hopping. The proposed method, NScaffold, which ranks PhGs based on the number of scaffolds covered by the PhGs, outperforms other conventional methods. As a demonstrative case, using a thrombin inhibitor data set, we interpreted the highest-ranked PhGs by NScaffold from the protein–ligand interaction point of view. It resulted that the NScaffold method successfully retrieved three known important interactions, showing the potential for identifying scaffold-hopped compounds with interpretable PhGs.
In rice (Oryza sativa L.) production, dry direct seeding is one of the most essential technologies to reduce labor input and to increase net income. Field experiments were conducted in southwestern ...Japan in 2019 and 2020 to determine the effects of nitrogen (N) application rate and timing on grain yield, lodging, grain appearance, and protein content in dry direct broadcast seeded rice under different weather conditions. In 2019, plants had larger source ability using the normal solar radiation at the tillering stage, regardless of N application timings. Plants with applied N at the reproductive stage produced the highest grain yield and the highest percentage of undamaged grains under high air temperature condition during the early ripening stage. In 2020, plants did not have larger source ability due to the lower solar radiation at the tillering stage. Plants with applied N at the reproductive stage produced the highest grain yield but produced the highest percentage of green immature grains. These results mean that solar radiation at the tillering stage may be important for increasing grain yield and quality in dry direct broadcast seeded rice. Therefore, since plants grown under normal solar radiation condition at the tillering stage may have large source ability, more N application at the reproductive stage may be recommended to increase grain yield. In contrast, since plants grown under low solar radiation condition at the tillering stage may have small source ability, less N application at the reproductive stage may be recommended to decrease the occurrence of green immature grains.
Core Ideas
Grain yield increased by nitrogen (N) application at reproductive.
Undamaged grains increased by N application at reproductive under high temperature at ripening.
Immature green grains occurred by N application at reproductive under low solar radiation at tillering.
Solar radiation at tillering was higher in 2019 than 2020, and grain yield was higher in 2019.
Solar radiation at tillering may be important for increasing grain yield and quality in broadcast rice.
The self-consistent charge density functional tight binding method was combined with the path-integral molecular dynamics method for the first time to evaluate the two-dimensional free-energy surface ...including nuclear quantum effects of a proton-transfer reaction in a 2,4-dichlorophenol–trimethylamine complex. A statistically converged two-dimensional quantum free-energy surface was evaluated by the multidimensional blue moon ensemble method. The accuracy was guaranteed by optimizing the repulsive potential between the sp3-hybridized nitrogen and hydrogen atoms in a SCC-DFTB3 parameter set for the system to reproduce high-level quantum chemical calculations. The present study illustrates the usefulness of this new approach to investigate nuclear quantum effects in various realistic proton-transfer reactions.
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