Showing papers by "Akita Prefectural University published in 2021"

Is there tree senescence? The fecundity evidence

Abstract: Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current estimates are dominated by overrepresentation of small trees in regression models. We combined global fecundity data, including a substantial representation of large trees. We compared size-fecundity relationships against traditional allometric scaling with diameter and two models based on crown architecture. All allometric models fail to describe the declining rate of increase in fecundity with diameter found for 80% of 597 species in our analysis. The strong evidence of declining fecundity, beyond what can be explained by crown architectural change, is consistent with physiological decline. A downward revision of projected fecundity of large trees can improve the next generation of forest dynamic models.

Generation and Starch Characterization of Non-Transgenic BEI and BEIIb Double Mutant Rice (Oryza sativa) with Ultra-High Level of Resistant Starch.

Abstract: Cereals high in resistant starch (RS) are gaining popularity, as their intake is thought to help manage diabetes and prediabetes. Number of patients suffering from diabetes is also increasing in Asian countries where people consume rice as a staple food, hence generation of practically growable high RS rice line has been anticipated. It is known that suppression of starch branching enzyme (BE) IIb increases RS content in cereals. To further increase RS content and for more practical use, we generated a non-transgenic be1 be2b double mutant rice (Oryza sativa) line, which completely lacked both proteins, by crossing a be1 mutant with a be2b mutant. The be1 be2b mutant showed a decrease in intermediate amylopectin chains and an increase in long amylopectin chains compared with be2b. The amylose content of be1 be2b mutant (51.7%) was the highest among all pre-existing non-transgenic rice lines. To understand the effects of chewing cooked rice and cooking rice flour on RS content, RS content of mashed and un-mashed cooked rice as well as raw and gelatinized rice flour were measured using be1 be2b and its parent mutant lines. The RS contents of mashed cooked rice and raw rice flour of be1 be2b mutant (28.4% and 35.1%, respectively) were 3-fold higher than those of be2b mutant. Gel-filtration analyses of starch treated with digestive enzymes showed that the RS in be1 be2b mutant was composed of the degradation products of amylose and long amylopectin chains. Seed weight of be1 be2b mutant was approximately 60% of the wild type and rather heavier than that of be2b mutant. The endosperm starch in be1 be2b double mutant rice were enriched with long amylopectin chains. This led to a great increase in RS content in cooked rice grains and rice flour in be1 be2b compared with be2b single mutant. be1 be2b generated in this study must serve as a good material for an ultra-high RS rice cultivar.

Poly(N-phenylglycine)-Based Bioinspired System for Stably and Efficiently Enhancing Solar Evaporation

Abstract: Realizing high-efficiency solar evaporation has great potential for purification of sewage and seawater desalination. However, continuous water supply, solar energy conversion, and thermal manageme...

On the cluster structure of amylopectin.

Abstract: Two opposing models for the amylopectin structure are historically and comprehensively reviewed, which leads us to a better understanding of the specific fine structure of amylopectin. Amylopectin is a highly branched glucan which accounts for approximately 65–85 of starch in most plant tissues. However, its fine structure is still not fully understood due to the limitations of current methodologies. Since the 1940 s, many scientists have attempted to elucidate the distinct structure of amylopectin. One of the most accepted concepts is that amylopectin has a structural element known as “cluster”, in which neighboring side chains with a degree of polymerization of ≥ 10 in the region of their non-branched segments form double helices. The double helical structures are arranged in inter- and intra-clusters and are the origin of the distinct physicochemical and crystalline properties of starch granules. Several models of the cluster structure have been proposed by starch scientists worldwide during the progress of analytical methods, whereas no direct evidence so far has been provided. Recently, Bertoft and colleagues proposed a new model designated as “the building block and backbone (BB) model”. The BB model sharply contrasts with the cluster model in that the structural element for the BB model is the building block, and that long chains are separately synthesized and positioned from short chains constituting the building block. In the present paper, we conduct the historical review of the cluster concept detailing how and when the concept was established based on experimental results by many scientists. Then, differences between the two opposing concepts are explained and both models are critically discussed, particularly from the point of view of the biochemical regulation of amylopectin biosynthesis.

Insecticide resistance by a host-symbiont reciprocal detoxification

Abstract: Insecticide resistance is one of the most serious problems in contemporary agriculture and public health. Although recent studies revealed that insect gut symbionts contribute to resistance, the symbiont-mediated detoxification process remains unclear. Here we report the in vivo detoxification process of an organophosphorus insecticide, fenitrothion, in the bean bug Riptortus pedestris. Using transcriptomics and reverse genetics, we reveal that gut symbiotic bacteria degrade this insecticide through a horizontally acquired insecticide-degrading enzyme into the non-insecticidal but bactericidal compound 3-methyl-4-nitrophenol, which is subsequently excreted by the host insect. This integrated “host-symbiont reciprocal detoxification relay” enables the simultaneous maintenance of symbiosis and efficient insecticide degradation. We also find that the symbiont-mediated detoxification process is analogous to the insect genome-encoded fenitrothion detoxification system present in other insects. Our findings highlight the capacity of symbiosis, combined with horizontal gene transfer in the environment, as a powerful strategy for an insect to instantly eliminate a toxic chemical compound, which could play a critical role in the human-pest arms race. Insect acquisition of insecticide resistance represents a serious problem for agriculture. Here, authors reveal an insect symbiotic bacteria that degrades insecticide fenitrothion into a non-insecticidal but bactericidal compound, which is subsequently excreted by the insect host.

A cast-in-place fabrication of high performance epoxy composites cured in an in-situ synthesized 3D foam of nanofibers

Abstract: A cast-in-place process is usually adopted to prepare bicontinuous composites which display good mechanical properties and excellent comprehensive performance. But the construction of an intercommunicating porous skeleton seems to be cumbersome and low efficient. Here we report a three-dimensional nanofibers foam (3D NFF), which has been fabricated and applied to enhance epoxy resin composite. The 3D NFF skeletons with densities from 0.028 to 0.218 g/cm3 were fabricated by regulating the conditions for the nanofiber growth. The 3D NFFs were conveniently modified with a silane coupling agent to improve the interface interaction with the epoxy matrix. Compared to the pure epoxy, the compressive strength of the cast-in-place processed 3D NFFs/epoxy composite was improved by 436.8% at loading of 3.9 wt%, and the flexural strength was increased by 133.5% at loading of 5.3 wt%. While the compressive and flexural strength of the NFPs/epoxy composite prepared through traditional mixing method was increased by 173.6% at loading of 3.9 wt%, and 63.1% at loading of 5.3 wt%, respectively.

Development of Drone-Mounted Multiple Sensing System with Advanced Mobility for In Situ Atmospheric Measurement: A Case Study Focusing on PM2.5 Local Distribution

Abstract: This study was conducted using a drone with advanced mobility to develop a unified sensor and communication system as a new platform for in situ atmospheric measurements. As a major cause of air pollution, particulate matter (PM) has been attracting attention globally. We developed a small, lightweight, simple, and cost-effective multi-sensor system for multiple measurements of atmospheric phenomena and related environmental information. For in situ local area measurements, we used a long-range wireless communication module with real-time monitoring and visualizing software applications. Moreover, we developed four prototype brackets with optimal assignment of sensors, devices, and a camera for mounting on a drone as a unified system platform. Results of calibration experiments, when compared to data from two upper-grade PM2.5 sensors, demonstrated that our sensor system followed the overall tendencies and changes. We obtained original datasets after conducting flight measurement experiments at three sites with differing surrounding environments. The experimentally obtained prediction results matched regional PM2.5 trends obtained using long short-term memory (LSTM) networks trained using the respective datasets.

Development of a mugineic acid family phytosiderophore analog as an iron fertilizer.

Abstract: Iron (Fe) is an essential nutrient, but is poorly bioavailable because of its low solubility in alkaline soils; this leads to reduced agricultural productivity. To overcome this problem, we first showed that the soil application of synthetic 2′-deoxymugineic acid, a natural phytosiderophore from the Poaceae, can recover Fe deficiency in rice grown in calcareous soil. However, the high cost and poor stability of synthetic 2′-deoxymugineic acid preclude its agricultural use. In this work, we develop a more stable and less expensive analog, proline-2′-deoxymugineic acid, and demonstrate its practical synthesis and transport of its Fe-chelated form across the plasma membrane by Fe(III)•2’-deoxymugineic acid transporters. Possibility of its use as an iron fertilizer on alkaline soils is supported by promotion of rice growth in a calcareous soil by soil application of metal free proline-2’-deoxymugineic acid. Iron is an essential plant nutrient that is poorly bioavailable in alkaline soils, resulting in reduced agricultural productivity. Here, the authors report the synthesis of stable and cheap iron-chelator, proline-2’-deoxymugineic acid (PDMA), and demonstrate its utility as potential fertilizer.

Who Is Next? A Study on Victims of Financial Fraud in Japan.

Abstract: Japan has seen an increase in the incidents of financial frauds over the last couple of decades. Although authorities are aware of the problem, an effective solution eludes them as fraudsters use innovative swindling methods and continually change the target group. Using a nationwide survey conducted by Hiroshima University, Japan, in 2020, this study investigated the socioeconomic and psychological profiles of victims of trending and special financial fraud such as fictitious billing fraud, loan guarantee fraud, and refund fraud. It was found that financial fraud victims' profiles are dissimilar at the aggregate and specific levels. At the specific level, victim profiles were diverse, that is, in fictitious billing fraud, loan guarantee fraud, and refund fraud cases. Males, married, and financially less satisfied people were more often victims of fictitious billing fraud; less anxious people were more likely victims of loan guarantee fraud; and older, asset-holding, and less-income-generating respondents were found to be victims of refund fraud. Our results also show some commonalities in the victims' profiles. For example, financially less-literate people were found to be more likely victims of fictitious billing fraud and loan guarantee fraud. Finally, respondents who lived with their family, those who did not have careful buying habits, and those who suffer from bouts of loneliness were found to be common victims of all types of special financial fraud. The results of our study suggest that a one-size-fits-all policy cannot effectively combat financial fraud.

Active-type starch synthase (SS) IIa from indica rice partially complements the sugary-1 phenotype in japonica rice endosperm

Abstract: Introduction of higher SSIIa activity to mild-type isa1 mutant by crossing results in restoration of crystallinity, starch granule structure, and production of plump seeds. Isoamylase 1 (ISA1) removes improper α-1, 6 glycosidic branches of amylopectin generated by starch branching enzymes and is essential for the formation of proper amylopectin structure. Rice isa1 (sug-1) mutants in japonica cultivar with less-active starch synthase IIa (SSIIa) and low granule-bound SSI (GBSSI) expression display wrinkled seed phenotype by accumulating water-soluble phytoglycogen instead of insoluble amylopectin. Expression of active SSIIa in transgenic rice produced with a severe-type isa1 mutant accumulated some insoluble glucan with weak B-type crystallinity at the periphery of seeds but their seeds remained wrinkled. To see whether introduction of high levels of SSIIa and/or GBSSI can restore the grain filling of the mild-type sug-1 mutant (EM653), new rice lines (SS2a gbss1L isa1, ss2aL GBSS1 isa1, and SS2a GBSS1 isa1) were generated by crossing japonica isa1 mutant (ss2aL gbss1L isa1) with wild type indica rice (SS2a GBSS1 ISA1). The results showed that SS2a gbss1L isa1 and SS2a GBSS1 isa1 lines generated chalky plump seeds accumulating insoluble amylopectin-like glucans with an increase in DP 13–35, while ss2aL GBSS1 isa1 generated wrinkly seeds and accumulated soluble glucans enriched with DP < 13. Scanning electron microscopic observation of cross-section of the seeds showed that SS2a gbss1L isa1 and SS2a GBSS1 isa1 produced wild type-like polygonal starch granules. These starches showed the A-type crystallinity comparable to the wild type, while the japonica isa1 mutant and the transgenic rice do not show any or little crystallinity, respectively. These results indicate that introduction of higher SSIIa activity can mostly complements the mild-type sug-1 phenotype.

SARS-CoV-2 mutations among minks show reduced lethality and infectivity to humans.

Abstract: SARS-CoV-2 infection in minks has become a serious problem, as the virus may mutate and reinfect humans; some countries have decided to cull minks Here, the virus sequencing data in minks were analysed and compared to those of human-virus Although the mink-virus maintained the characteristics of human-virus, some variants rapidly mutated, adapting to minks Some mink-derived variants infected humans, which accounted for 40% of the total SARS-CoV-2 cases in the Netherlands These variants appear to be less lethal and infective compared to those in humans Variants that have mutated further among minks were not found in humans Such mink-viruses might be suitable for vaccination for humans, such as in the case of the smallpox virus, which is less infective and toxic to humans

Elucidation of Novel cis-Regulatory Elements and Promoter Structures Involved in Iron Excess Response Mechanisms in Rice Using a Bioinformatics Approach

Abstract: Iron (Fe) excess is a major constraint on crop production in flooded acidic soils, particularly in rice cultivation. Under Fe excess, plants activate a complex mechanism and network regulating Fe exclusion by roots and isolation in various tissues. In rice, the transcription factors and cis-regulatory elements (CREs) that regulate Fe excess response mechanisms remain largely elusive. We previously reported comprehensive microarray analyses of several rice tissues in response to various levels of Fe excess stress. In this study, we further explored novel CREs and promoter structures in rice using bioinformatics approaches with this microarray data. We first performed network analyses to predict Fe excess-related CREs through the categorization of the gene expression patterns of Fe excess-responsive transcriptional regulons, and found four major expression clusters: Fe storage type, Fe chelator type, Fe uptake type, and WRKY and other co-expression type. Next, we explored CREs within these four clusters of gene expression types using a machine-learning method called microarray-associated motif analyzer (MAMA), which we previously established. Through a comprehensive bioinformatics approach, we identified a total of 560 CRE candidates extracted by MAMA analyses and 42 important conserved sequences of CREs directly related to the Fe excess response in various rice tissues. We explored several novel cis-elements as candidate Fe excess CREs including GCWGCWGC, CGACACGC, and Myb binding-like motifs. Based on the presence or absence of candidate CREs using MAMA and known PLACE CREs, we found that the Boruta-XGBoost model explained expression patterns with high accuracy of about 83%. Enriched sequences of both novel MAMA CREs and known PLACE CREs led to high accuracy expression patterns. We also found new roles of known CREs in the Fe excess response, including the DCEp2 motif, IDEF1-, Zinc Finger-, WRKY-, Myb-, AP2/ERF-, MADS- box-, bZIP and bHLH- binding sequence-containing motifs among Fe excess-responsive genes. In addition, we built a molecular model and promoter structures regulating Fe excess-responsive genes based on new finding CREs. Together, our findings about Fe excess-related CREs and conserved sequences will provide a comprehensive resource for discovery of genes and transcription factors involved in Fe excess-responsive pathways, clarification of the Fe excess response mechanism in rice, and future application of the promoter sequences to produce genotypes tolerant of Fe excess.

Exposure to 4-nonylphenol induces a shift in the gene expression of gsdf and testis-ova formation and sex reversal in Japanese medaka (Oryzias latipes).

Abstract: The branched isomer mixture 4-nonylphenol (4-NP) has been used worldwide as a surfactant, and can have endocrine-disrupting effects on aquatic organisms. For instance, 4-NP induces the formation of testis-ova (i.e., testicular and ovarian tissue in the same gonad) or male to female sex reversal of various teleost fishes. Recently, our group revealed that altered gsdf gene expression is associated with disruption of gonadal differentiation in Japanese medaka (Oryzias latipes) embryos exposed to methyltestosterone or bisphenol A, suggesting that gsdf might be useful as a biomarker for predicting the impact of endocrine-disrupting chemicals (EDCs) on gonadal differentiation. Here, we used 4-NP to examine further whether gsdf expression at the embryo stage is useful for predicting EDC impact on gonadal sex differentiation. When fertilized medaka eggs were exposed to 32 or 100 μg/L 4-NP, testis-ova in genetic males and sex reversal from genetic male to phenotypic female were observed. At stage 38 (just before hatching), 4-NP exposure at 1-100 μg/L did not affect gsdf expression in XX embryos compared with the nontreated control; however, in XY embryos, the gsdf expression in the 100 μg/L-exposed group was significantly lower than that in the controls. The 4-NP concentration at which gsdf expression was suppressed was equal to that at which testis-ova and sex reversal were induced. These results indicate that expression of the gsdf gene at the embryonic stage in medaka is a useful biomarker for predicting the impact of EDCs on sexual differentiation.

Starch synthases SSIIa and GBSSI control starch structure but do not determine starch granule morphology in the absence of SSIIIa and SSIVb.

Abstract: High levels of two major starch synthases, SSIIa and GBSSI, in ss3a ss4b double mutant rice alter the starch structure but fail to recover the polygonal starch granule morphology. The endosperm starch granule is polygonal in wild-type rice but spherical in double mutant japonica rice lacking genes encoding two of the five major Starch synthase (SS) isozymes expressed in endosperm, SSIIIa and SSIVb. Japonica rice naturally has low levels of SSIIa and Granule-bound SSI (GBSSI). Therefore, introduction of active SSIIa allele and/or high-expressing GBSSI allele from indica rice into the japonica rice mutant lacking SS isozymes can help elucidate the compensatory roles of SS isozymes in starch biosynthesis. In this study, we crossed the ss3a ss4a double mutant japonica rice with the indica rice to generate three new rice lines with high and/or low SSIIa and GBSSI levels, and examined their starch structure, physicochemical properties, and levels of other starch biosynthetic enzymes. Lines with high SSIIa levels showed more SSI and SSIIa bound to starch granule, reduced levels of short amylopectin chains (7 ≤ DP ≤ 12), increased levels of amylopectin chains with DP > 13, and consequently higher gelatinization temperature. Lines with high GBSSI levels showed an increase in amylose content. The ADP-glucose content of the crude extract was high in lines with low or high SSIIa and low GBSSI levels, but was low in lines with high GBSSI. Addition of high SSIIa and GBSSI altered the starch structure and physicochemical properties but did not affect the starch granule morphology, confirming that SSIIIa and SSIVb are key enzymes affecting starch granule morphology in rice. The relationship among SS isozymes and its effect on the amount of substrate (ADP-glucose) is discussed.

Simple preparation of carboxymethyl cellulose-based ionic conductive hydrogels for highly sensitive, stable and durable sensors

Abstract: Ionic conductive hydrogels have recently been increasingly studied due to their broad applications in sensing and flexible devices. Nevertheless, it is still a challenge to simply develop an ionic conductive hydrogel with satisfying comprehensive performance. Herein, ionic conductive hydrogels have been crosslinked by carboxymethyl cellulose and phytic acid via a simple one-pot approach to address these challenges. The unique double crosslinked microstructure ensures that the hydrogel has favourable mechanical performance, resilience (93%, similar to natural resilin), and recovery (20 min, after 7 cycles at 300%) along with less residual strain (6.7%, after 20 successive cycles at 125%). The hydrogel also exhibits outstanding ionic conductivity (6.0 S/m). The combined mechanical performance and ionic conductivity of the prepared hydrogel results in its remarkable performance when used in sensors. The hydrogel-based sensor displays superior sensitivity (GF of 2.86, at a strain of 600%), stability and durability towards both tensile and compressive deformation. In practical applications, the sensor demonstrates a broad strain window to detect both large and very small human activities, showing the excellent potential of this hydrogel in sensing and flexible devices. The approach in this work has also been optimized to potentially allow for large-area, low-cost fabrication.

L-Arginine Exerts Excellent Anti-Stress Effects on Stress-Induced Shortened Lifespan, Cognitive Decline and Depression.

Abstract: The anti-stress potential of dietary L-arginine (Arg) was assessed in psychosocially stress-loaded senescence-accelerated (SAMP10) mice. Although this strain of mouse is sensitive to stress, daily administration of Arg at 3 mg/kg significantly suppressed aging-related cognitive decline and behavioral depression at nine months of age and counteracted stress-induced shortened lifespan. To investigate the mechanism of the anti-stress effect of Arg in the brain, early changes in oxidative damage and gene expression levels were measured using SAMP10 mice that were stress-loaded for three days. Increased lipid peroxidation in the brains of stressed mice was significantly lowered by Arg intake. Several genes associated with oxidative stress response and neuronal excitotoxic cell death, including Nr4a1, Arc, and Cyr61, remarkably increased in response to psychosocial stress; however, their expression was significantly suppressed in mice that ingested Arg even under stress conditions. In contrast, the genes that maintain mitochondrial functions and neuronal survival, including Hba-a2 and Hbb-b2, were significantly increased in mice that ingested Arg. These results indicate that Arg reduces oxidative damage and enhances mitochondrial functions in the brain. We suggest that the daily intake of Arg plays important roles in reducing stress-induced brain damage and slowing aging.