Mimicking the retinal neuron functions by a photoresponsive single transistor with a double gate.

To realize a low-cost neuromorphic visual system, employing an artificial neuron capable of mimicking the retinal neuron functions is essential. A photoresponsive single transistor neuron composed of a vertical silicon nanowire is proposed. Similar to retinal neurons, various photoresponsive characteristics of the single transistor neuron can be modulated by light intensity as well as wavelength and have a high responsivity to green light like the human eye. The device is designed with a cylindrical surrounding double-gate structure, enclosed by an independently controlled outer gate and inner gate. The outer gate has the function of selectively inhibiting neuron activity, which can mimic lateral inhibition of amacrine cells to ganglion cells, and the inner gate can be utilized for the adjustment of the firing threshold voltage, which can be used to mimic the regulation of photoresponsivity by horizontal cells for adaptive visual perception. Furthermore, a myelination function that controls the speed of information transmission is obtained according to the inherent asymmetric source/drain structure of a vertical silicon nanowire. This work can enable photoresponsive neuronal function using only a single transistor, providing a promising hardware implementation for building miniaturized neuromorphic vision systems at low cost.

Transcriptomic analysis of salt-tolerant and sensitive high-yield japonica rice (Oryza sativa L.) reveals complicated salt-tolerant mechanisms.

Developing and cultivating rice varieties is a potent strategy for reclaiming salinity-affected soils for rice production. Nevertheless, the molecular mechanisms conferring salt tolerance, especially in conventional high-yield japonica rice varieties, remain obscure. In this study, Zhendao 23309 (ZD23309) exhibited significantly less grain yield reduction under a salt stress gradient than the control variety Wuyunjing 30 (WYJ30). High positive correlations between grain yield and dry matter accumulation at the jointing, heading and maturity stages indicated that early salt tolerance performance is a crucial hallmark for yield formation. After a mild salt stress (85 mM NaCl) of young seedlings, RNA sequencing (RNA-seq) of shoot and root separately identified a total of 1952 and 3647 differentially expressed genes (DEGs) in ZD23309, and 2114 and 2711 DEGs in WYJ30, respectively. Gene ontology (GO) analysis revealed numerous DEGs in ZD23309 that play pivotal roles in strengthening salt tolerance, encompassing the response to stimulus (GO:0050896) in shoots and nucleoside binding (GO:0001882) in roots. Additionally, distinct expression patterns were observed in a fraction of genes in the two rice varieties under salt stress, corroborating the efficacy of previously reported salt tolerance genes. Our research not only offers fresh insights into the differences in salt stress tolerance among conventional high-yield rice varieties but also unveils the intricate nature of salt tolerance mechanisms. These findings lay a solid groundwork for deciphering the mechanisms underlying salt tolerance.

The Explanation of Photopic Luminous Efficiency Curve by Using Both of the Cones' Optical Fiber Coupling Effects and the Absorption of L Cones.

In this paper, we build four-part cone models to explore the coupling effect of seven cone fiber couplers. Moreover, this is the first study of the coupling effect of four layers of biological couplers in animals and other biological lives. We simulate the four layers cone couplers by using the beam propagation method, and we assume the input beam is located at the outer fiber of the central cone. Our simulation results showed that there are two wavelength regions (short and long wavelength regions) with the strongest coupling, where the most power of input optical powers of the central cones will transfer to the six surrounding cones after transmitting through the four layers of cone couplers. However, within a wavelength region of ±75 nm near to the peak wavelengths, located in the yellow-green wavelength range, the splitting ratios at the output of the outer segment of the central cone are always greater than the sum of the splitting ratios of the six surrounding cones. These cone couplers may play an important role in color preprocessing (e.g., doing opponent color processing partially). The cone fiber coupler effect and light absorption of cones are considered separately in our models. By taking account of both the cone fiber coupling effect and absorption of outer segment of L cone, we find the multiplication of the relative optical power of cone couplers, the spectral sensitivity data of the L cone, and a normalized coefficient that matches with the photopic luminous efficiency of the human eye well. This is the attempt to use both the cone fiber coupling effect and the absorption of L cones to explain the photopic luminous efficiency. The splitting ratios of the central cones are greater than 80% at peak wavelengths located in the yellow-green wavelength range, and this can help to explain why the human eye is more sensitive to green light.

OsCOMT, encoding a caffeic acid O-methyltransferase in melatonin biosynthesis, increases rice grain yield through dual regulation of leaf senescence and vascular development.

Melatonin, a natural phytohormone in plants, plays multiple critical roles in plant growth and stress responses. Although melatonin biosynthesis-related genes have been suggested to possess diverse biological functions, their roles and functional mechanisms in regulating rice grain yield remain largely unexplored. Here, we uncovered the roles of a caffeic acid O-methyltransferase (OsCOMT) gene in mediating rice grain yield through dual regulation of leaf senescence and vascular development. In vitro and in vivo evidence revealed that OsCOMT is involved in melatonin biosynthesis. Transgenic assays suggested that OsCOMT significantly delays leaf senescence at the grain filling stage by inhibiting degradation of chlorophyll and chloroplast, which, in turn, improves photosynthesis efficiency. In addition, the number and size of vascular bundles in the culms and leaves were significantly increased in the OsCOMT-overexpressing plants, while decreased in the knockout plants, suggesting that OsCOMT plays a positive role in vascular development of rice. Further evidence indicated that OsCOMT-mediated vascular development might owe to the crosstalk between melatonin and cytokinin. More importantly, we found that OsCOMT is a positive regulator of grain yield, and overexpression of OsCOMT increase grain yield per plant even in a high-yield variety background, suggesting that OsCOMT can be used as an important target for enhancing rice yield. Our findings shed novel insights into melatonin-mediated leaf senescence and vascular development and provide a possible strategy for genetic improvement of rice grain yield.

AQP1 suppression by ATF4 triggers trabecular meshwork tissue remodelling in ET-1-induced POAG.

Primary open-angle glaucoma (POAG) is the second leading cause of irreversible blindness worldwide. Increased endothelin-1 (ET-1) has been observed in aqueous humour (AH) of POAG patients, resulting in an increase in the out-flow resistance of the AH. However, the underlining mechanisms remain elusive. Using established in vivo and in vitro POAG models, we demonstrated that water channel Aquaporin 1 (AQP1) is down-regulated in trabecular meshwork (TM) cells upon ET-1 exposure, which causes a series of glaucomatous changes, including actin fibre reorganization, collagen production, extracellular matrix deposition and contractility alteration of TM cells. Ectopic expression of AQP1 can reverse ET-1-induced TM tissue remodelling, which requires the presence of ß-catenin. More importantly, we found that ET-1-induced AQP1 suppression is mediated by ATF4, a transcription factor of the unfolded protein response, which binds to the promoter of AQP1 and negatively regulates AQP1 transcription. Thus, we discovered a novel function of ATF4 in controlling the process of TM remodelling in ET-1-induced POAG through transcription suppression of AQP1. Our findings also detail a novel pathological mechanism and a potential therapeutic target for POAG.

Mutation of RGG2, which encodes a type B heterotrimeric G protein γ subunit, increases grain size and yield production in rice.

Heterotrimeric G proteins, which consist of Gα , Gß and Gγ subunits, function as molecular switches that regulate a wide range of developmental processes in plants. In this study, we characterised the function of rice RGG2, which encodes a type B Gγ subunit, in regulating grain size and yield production. The expression levels of RGG2 were significantly higher than those of other rice Gγ -encoding genes in all tissues tested, suggesting that RGG2 plays essential roles in rice growth and development. By regulating cell expansion, overexpression of RGG2 in Nipponbare (NIP) led to reduced plant height and decreased grain size. By contrast, two mutants generated by the clustered, regularly interspaced, short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) system in the Zhenshan 97 (ZS97) background, zrgg2-1 and zrgg2-2, exhibited enhanced growth, including elongated internodes, increased 1000-grain weight and plant biomass and enhanced grain yield per plant (+11.8% and 16.0%, respectively). These results demonstrate that RGG2 acts as a negative regulator of plant growth and organ size in rice. By measuring the length of the second leaf sheath after gibberellin (GA3 ) treatment and the GA-induced α-amylase activity of seeds, we found that RGG2 is also involved in GA signalling. In summary, we propose that RGG2 may regulate grain and organ size via the GA pathway and that manipulation of RGG2 may provide a novel strategy for rice grain yield enhancement.

The Spermine Synthase OsSPMS1 Regulates Seed Germination, Grain Size, and Yield.

Polyamines, including putrescine, spermidine, and spermine, play essential roles in a wide variety of prokaryotic and eukaryotic organisms. Rice (Oryza sativa) contains four putative spermidine/spermine synthase (SPMS)-encoding genes (OsSPMS1, OsSPMS2, OsSPMS3, and OsACAULIS5), but none have been functionally characterized. In this study, we used a reverse genetic strategy to investigate the biological function of OsSPMS1 We generated several homozygous RNA interference (RNAi) and overexpression (OE) lines of OsSPMS1 Phenotypic analysis indicated that OsSPMS1 negatively regulates seed germination, grain size, and grain yield per plant. The ratio of spermine to spermidine was significantly lower in the RNAi lines and considerably higher in the OE lines than in the wild type, suggesting that OsSPMS1 may function as a SPMS. S-Adenosyl-l-methionine is a common precursor of polyamines and ethylene biosynthesis. The 1-aminocyclopropane-1-carboxylic acid (ACC) and ethylene contents in seeds increased significantly in RNAi lines and decreased in OE lines, respectively, compared with the wild type. Additionally, the reduced germination rates and growth defects of OE lines could be rescued with ACC treatment. These data suggest that OsSPMS1 affects ethylene synthesis and may regulate seed germination and plant growth by affecting the ACC and ethylene pathways. Most importantly, an OsSPMS1 knockout mutant showed an increase in grain yield per plant in a high-yield variety, Suken118, suggesting that OsSPMS1 is an important target for yield enhancement in rice.

Origin, evolution and functional characterization of the land plant glycoside hydrolase subfamily GH5_11.

Colonization of the land by plants was a critical event in the establishment of modern terrestrial ecosystems, and many characteristics of land plants originated during this process, including the emergence of rosette terminal cellulose-synthesizing complexes. Cellulases are non-homologous isofunctional enzymes, encoded by glycosyl hydrolase (GH) gene families. Although the plant GH5_11 gene subfamily is presumed to encode a cell-wall degrading enzyme, its evolutionary and functional characteristics remain unclear. In the present study, we report the evolution of the land plant GH5_11 subfamily, and the functions of its members in terms of cellulase activity, through comprehensive phylogenetic analyses and observation of Arabidopsis mutants. Phylogenetic and sequence similarity analyses reveal that the ancestor of land plants acquired the GH5_11 gene from fungi through a horizontal gene transfer (HGT) event. Subsequently, positive selection with massive gene duplication and loss events contributed to the evolution of this subfamily in land plants. In Arabidopsis and rice, expression of GH5_11 genes are regulated by multiple abiotic stresses, the duplicated genes showing different patterns of expression. The Arabidopsis mutants atgh5_11a and atgh5_11c display low levels of cellulase and endoglucanase activities, with correspondingly high levels of cellulose, implying that the encoded proteins may function as endoglucanases. However, atgh5_11a and atgh5_11c also display an enlarged rosette leaf phenotype, and atgh5_11c is late-flowering under short photoperiods. These observations suggest that plant GH5_11s possess more functions beyond being endonucleases. To summarize, we demonstrate that the ancestor of land plants has acquired GH5_11 gene through HGT, which extends the cellulose degradation complexity. Our investigations illuminate features of part of the molecular framework underlying the origin of land plants and provide a focus on the cellulose degradation pathway.

Transcriptomic and Co-Expression Network Profiling of Shoot Apical Meristem Reveal Contrasting Response to Nitrogen Rate between Indica and Japonica Rice Subspecies.

Reducing nitrogen (N) input is a key measure to achieve a sustainable rice production in China, especially in Jiangsu Province. Tiller is the basis for achieving panicle number that plays as a major factor in the yield determination. In actual production, excessive N is often applied in order to produce enough tillers in the early stages. Understanding how N regulates tillering in rice plants is critical to generate an integrative management to reduce N use and reaching tiller number target. Aiming at this objective, we utilized RNA sequencing and weighted gene co-expression network analysis (WGCNA) to compare the transcriptomes surrounding the shoot apical meristem of indica (Yangdao6, YD6) and japonica (Nipponbare, NPB) rice subspecies. Our results showed that N rate influenced tiller number in a different pattern between the two varieties, with NPB being more sensitive to N enrichment, and YD6 being more tolerant to high N rate. Tiller number was positively related to N content in leaf, culm and root tissue, but negatively related to the soluble carbohydrate content, regardless of variety. Transcriptomic comparisons revealed that for YD6 when N rate enrichment from low (LN) to medium (MN), it caused 115 DEGs (LN vs. MN), from MN to high level (HN) triggered 162 DEGs (MN vs. HN), but direct comparison of low with high N rate showed a 511 DEGs (LN vs. HN). These numbers of DEG in NPB were 87 (LN vs. MN), 40 (MN vs. HN), and 148 (LN vs. HN). These differences indicate that continual N enrichment led to a bumpy change at the transcription level. For the reported sixty-five genes which affect tillering, thirty-six showed decent expression in SAM at tiller starting phase, among them only nineteen being significantly influenced by N level, and two genes showed significant interaction between N rate and variety. Gene ontology analysis revealed that the majority of the common DEGs are involved in general stress responses, stimulus responses, and hormonal signaling process. WGCNA network identified twenty-two co-expressing gene modules and ten candidate hubgenes for each module. Several genes associated with tillering and N rate fall on the related modules. These indicate that there are more genes participating in tillering regulation in response to N enrichment.

Global Transcriptome and Co-Expression Network Analysis Reveal Contrasting Response of Japonica and Indica Rice Cultivar to γ Radiation.

Japonica and indica are two important subspecies in cultivated Asian rice. Irradiation is a classical approach to induce mutations and create novel germplasm. However, little is known about the differential response between japonica and indica rice after γ radiation. Here, we utilized the RNA sequencing and Weighted Gene Co-expression Network Analysis (WGCNA) to compare the transcriptome differences between japonica Nipponbare (NPB) and indica Yangdao6 (YD6) in response to irradiation. Japonica subspecies are more sensitive to irradiation than the indica subspecies. Indica showed a higher seedling survival rate than japonica. Irradiation caused more extensive DNA damage in shoots than in roots, and the severity was higher in NPB than in YD6. GO and KEGG pathway analyses indicate that the core genes related to DNA repair and replication and cell proliferation are similarly regulated between the varieties, however the universal stress responsive genes show contrasting differential response patterns in japonica and indica. WGCNA identifies 37 co-expressing gene modules and ten candidate hub genes for each module. This provides novel evidence indicating that certain peripheral pathways may dominate the molecular networks in irradiation survival and suggests more potential target genes in breeding for universal stress tolerance in rice.

Potentiation of hepatic stellate cell activation by extracellular ATP is dependent on P2X7R-mediated NLRP3 inflammasome activation.

Purinergic receptor P2x7 (P2x7R) is a key modulator of liver inflammation and fibrosis. The present study aimed to investigate the role of P2x7R in hepatic stellate cells activation. Lipopolysaccharide (LPS) or the conditioned medium (CM) from LPS-stimulated RAW 264.7 mouse macrophages was supplemented to human hepatic stellate cells, LX-2 for 24h and P2x7R selective antagonist A438079 (10µM) was supplemented to LX-2 cells 1h before LPS or CM stimulation. In addition LX-2 cells were primed with LPS for 4h and subsequently stimulated for 30min with 3mM of adenosine 5'-triphosphate (ATP). A438079 was supplemented to LX-2 cells 10min prior to ATP. Directly treated with LPS on LX-2 cells, mRNA expressions of interleukin (IL)-1ß, IL-18 and IL-6 were increased, as well as mRNA expressions of P2x7R, caspase-1, apoptosis-associated speck-like protein containing CARD (ASC) and NOD-like receptor family, pyrin domain containing 3 (NLRP3) mRNA. LPS also increased α-smooth muscle actin (α-SMA) and type I collagen mRNA expressions, as well as collagen deposition. Interestingly treatment of LX-2 cells with LPS-activated CM exhibited the greater increase of above factors than those in LX-2 cells directly treated with LPS. Pretreatment of A438079 on LX-2 cells stimulated by LPS or LPS-activated CM both suppressed IL-1ß mRNA expression. LPS combined with ATP dramatically increased protein synthesis and cleavage of IL-1ß and its mRNA level than those in HSC treated with LPS or ATP alone. Additionally LX-2 cells primed with LPS and subsequently stimulated for 30min with ATP greatly increased mRNA and protein expression of caspase-1, NLRP3 and P2x7R, as well as liver fibrosis markers, α-SMA and type I collagen. These events were remarkably suppressed by A438079 pretreatment. siRNA against P2x7R reduced protein expression of NLRP3 and α-SMA, and suppressed deposition and secretion of type I collagen. The involvement of P2X7R-mediated NLRP3 inflammasome activation in IL-1ß production of HSC might contribute to ECM deposition and suggests that blockade of the P2x7R-NLRP3 inflammasome axis represents a potential therapeutic target to liver fibrosis.

Betulin alleviated ethanol-induced alcoholic liver injury via SIRT1/AMPK signaling pathway.

The present study was conducted to investigate the protective effect of betulin, a triterpene from the bark of Betula platyphylla Suk, against ethanol-induced alcoholic liver injury and its possible underlying mechanisms. In vitro, human hepatic stellate cell line, LX-2 cells were treated with betulin (6.25, 12.5 and 25 µM) prior to ethanol (50mM) for 24h. Cell viability was analyzed by methyl thiazolyl tetrazolium assay, protein expressions were assessed by Western blot. In vivo, we induced alcoholic liver injury in male C57BL/6 mice, placing them on Lieber-DeCarli ethanol-containing diets for 10 days and then administering a single dose of ethanol (5 g/kg body weight) via gavage. Betulin (20 and 50mg/kg) were given by gavage every day. In vitro results showed that betulin effectively decreased LX-2 cell viability, attenuated collagen-I, α-smooth muscle actin (α-SMA) levels, activated liver kinase B-1 (LKB1) and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. Betulin suppressed the expression of sterol regulatory element-binding protein-1 (SREBP-1), and genetic deletion of AMPK blocked the effect of betulin on SREBP-1 in ethanol treated LX-2 cells. In vivo, betulin attenuated the increases in serum aminotransferase and triglyceride levels in the mice fed with chronic-binge ethanol, while significantly inhibited SREBP-1 expression and activated LKB1-AMPK phosphorylation. Additionally, betulin enhanced the sirtuin 1 (SIRT1) expression mediated by ethanol. Taken together, betulin alleviates alcoholic liver injury possibly through blocking the regulation of SREBP-1 on fatty acid synthesis and activating SIRT1-LKB1-AMPK signaling pathway.

Salidroside Regulates Inflammatory Response in Raw 264.7 Macrophages via TLR4/TAK1 and Ameliorates Inflammation in Alcohol Binge Drinking-Induced Liver Injury.

The current study was designed to investigate the anti-inflammatory effect of salidroside (SDS) and the underlying mechanism by using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages in vitro and a mouse model of binge drinking-induced liver injury in vivo. SDS downregulated protein expression of toll-like receptor 4 (TLR4) and CD14. SDS inhibited LPS-triggered phosphorylation of LPS-activated kinase 1 (TAK1), p38, c-Jun terminal kinase (JNK), and extracellular signal-regulated kinase (ERK). Degradation of IκB-α and nuclear translocation of nuclear factor (NF)-κB were effectively blocked by SDS. SDS concentration-dependently suppressed LPS mediated inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein levels, as well as their downstream products, NO. SDS significantly inhibited protein secretion and mRNA expression of of interleukin (IL)-1ß and tumor necrosis factor (TNF)-α. Additionally C57BL/6 mice were orally administrated SDS for continuous 5 days, followed by three gavages of ethanol every 30 min. Alcohol binge drinking caused the increasing of hepatic lipid accumulation and serum transaminases levels. SDS pretreatment significantly alleviated liver inflammatory changes and serum transaminases levels. Further investigation indicated that SDS markedly decreased protein level of IL-1ß in serum. Taken together, these data implied that SDS inhibits liver inflammation both in vitro and in vivo, and may be a promising candidate for the treatment of inflammatory liver injury.

Ancestral exposure to stress epigenetically programs preterm birth risk and adverse maternal and newborn outcomes.

BACKGROUND: Chronic stress is considered to be one of many causes of human preterm birth (PTB), but no direct evidence has yet been provided. Here we show in rats that stress across generations has downstream effects on endocrine, metabolic and behavioural manifestations of PTB possibly via microRNA (miRNA) regulation. METHODS: Pregnant dams of the parental generation were exposed to stress from gestational days 12 to 18. Their pregnant daughters (F1) and grand-daughters (F2) either were stressed or remained as non-stressed controls. Gestational length, maternal gestational weight gain, blood glucose and plasma corticosterone levels, litter size and offspring weight gain from postnatal days 1 to 30 were recorded in each generation, including F3. Maternal behaviours were analysed for the first hour after completed parturition, and offspring sensorimotor development was recorded on postnatal day (P) 7. F0 through F2 maternal brain frontal cortex, uterus and placenta miRNA and gene expression patterns were used to identify stress-induced epigenetic regulatory pathways of maternal behaviour and pregnancy maintenance. RESULTS: Progressively up to the F2 generation, stress gradually reduced gestational length, maternal weight gain and behavioural activity, and increased blood glucose levels. Reduced offspring growth and delayed behavioural development in the stress cohort was recognizable as early as P7, with the greatest effect in the F3 offspring of transgenerationally stressed mothers. Furthermore, stress altered miRNA expression patterns in the brain and uterus of F2 mothers, including the miR-200 family, which regulates pathways related to brain plasticity and parturition, respectively. Main miR-200 family target genes in the uterus, Stat5b, Zeb1 and Zeb2, were downregulated by multigenerational stress in the F1 generation. Zeb2 was also reduced in the stressed F2 generation, suggesting a causal mechanism for disturbed pregnancy maintenance. Additionally, stress increased placental miR-181a, a marker of human PTB. CONCLUSIONS: The findings indicate that a family history of stress may program central and peripheral pathways regulating gestational length and maternal and newborn health outcomes in the maternal lineage. This new paradigm may model the origin of many human PTB causes.

Transient down-regulation of the RNA silencing machinery increases efficiency of Agrobacterium-mediated transformation of Arabidopsis.

Agrobacterium tumefaciens is a plant pathogen that is widely used in plant transformation. As the process of transgenesis includes the delivery of single-stranded T-DNA molecule, we hypothesized that transformation rate may negatively correlate with the efficiency of the RNA-silencing machinery. Using mutants compromised in either the transcriptional or post-transcriptional gene-silencing pathways, two inhibitors of stable transformation were revealed-AGO2 and NRPD1a. Furthermore, an immunoprecipitation experiment has shown that NRPD1, a subunit of Pol IV, directly interacts with Agrobacterium T-DNA in planta. Using the Tobacco rattle virus (TRV)--based virus-induced gene silencing (VIGS) technique, we demonstrated that the transient down-regulation of the expression of either AGO2 or NRPD1a genes in reproductive organs of Arabidopsis, leads to an increase in transformation rate. We observed a 6.0- and 3.5-fold increase in transformation rate upon transient downregulation of either AGO2 or NRPD1a genes, respectively. This is the first report demonstrating the increase in the plant transformation rate via VIGS-mediated transient down-regulation of the components of epigenetic machinery in reproductive tissue.

UV-C-irradiated Arabidopsis and tobacco emit volatiles that trigger genomic instability in neighboring plants.

We have previously shown that local exposure of plants to stress results in a systemic increase in genome instability. Here, we show that UV-C-irradiated plants produce a volatile signal that triggers an increase in genome instability in neighboring nonirradiated Arabidopsis thaliana plants. This volatile signal is interspecific, as UV-C-irradiated Arabidopsis plants transmit genome destabilization to naive tobacco (Nicotiana tabacum) plants and vice versa. We report that plants exposed to the volatile hormones methyl salicylate (MeSA) or methyl jasmonate (MeJA) exhibit a similar level of genome destabilization as UV-C-irradiated plants. We also found that irradiated Arabidopsis plants produce MeSA and MeJA. The analysis of mutants impaired in the synthesis and/or response to salicylic acid (SA) and/or jasmonic acid showed that at least one other volatile compound besides MeSA and MeJA can communicate interplant genome instability. The NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (npr1) mutant, defective in SA signaling, is impaired in both the production and the perception of the volatile signals, demonstrating a key role for NPR1 as a central regulator of genome stability. Finally, various forms of stress resulting in the formation of necrotic lesions also generate a volatile signal that leads to genomic instability.

Genome stability in the uvh6 mutant of Arabidopsis thaliana.

Plant XPD homolog UVH6 is the protein involved in the repair of strand breaks, and the excision repair and uvh6 mutant is not impaired in transgenerational increase in HRF. While analyzing the transgenerational response to stress in plants, we found that the promoter and gene body of Arabidopsis thaliana (Arabidopsis) XPD homolog UVH6 underwent hypomethylation and showed an increase in the level of transcript. Here, we analyzed the mutant of this gene, uvh6-1, by crossing it to two different reporter lines: one which allows for analysis of homologous recombination frequency (HRF) and another which makes it possible to analyze the frequency of point mutations. We observed that uvh6-1 plants exhibited lower rate of spontaneous homologous recombination but higher frequencies of spontaneous point mutations. The analysis of strand breaks using ROPS and Comet assays showed that the mutant had a much higher level of strand breaks at non-induced conditions. Exposure to stresses such as UVC, heat, cold, flood and drought showed that the mutant was not impaired in an increase in somatic HRF. The analysis of spontaneous HRF in the progeny of control plants compared to that of the progeny of stressed plants demonstrated that uvh6-1 was mildly affected in response to temperature, UV and drought. Our data suggest that UVH6 may be involved in the repair of strand breaks and excision repair, but it is unlikely that UVH6 is required for transgenerational increase in HRF.

Jaceosidin attenuates the progression of hepatic fibrosis by inhibiting the VGLL3/HMGB1/TLR4 signaling pathway.

BACKGROUND: Jaceosidin (JA) is a natural flavone extracted from Artemisia that is used as a food and traditional medicinal herb. It has been reported to possess numerous biological activities. However, the regulatory mechanisms underlying amelioration of hepatic fibrosis remain unclear. HYPOTHESIS/PURPOSE: We hypothesized that jaceosidin acid (JA) modulates hepatic fibrosis and inflammation. METHODS: Thioacetamide (TAA) was used to establish an HF mouse model. In vitro, mouse primary hepatocytes and HSC-T6 cells were induced by TGF-ß, whereas mouse peritoneal macrophages received a treatment lipopolysaccharide (LPS)/ATP. RESULTS: JA decreased serum transaminase levels and improved hepatic histological pathology in TAA-treated mice stimulated by TAA. Moreover, the expression of pro-fibrogenic biomarkers associated with the activation of liver stellate cells was downregulated by JA. Likewise, JA down-regulated the expression of vestigial-like family member 3 (VGLL3), high mobility group protein B1 (HMGB1), toll-like receptors 4 (TLR4), and nucleotide-binding domain-(NOD-) like receptor protein 3 (NLRP3), thereby inhibiting the inflammatory response and inhibiting the release of mature-IL-1ß in TAA-stimulated mice. Additionally, JA suppressed HMGB1 release and NLRP3/ASC inflammasome activation in LPS/ATP-stimulated murine peritoneal macrophages. JA decreases the expression of pro-fibrogenic biomarkers related to liver stellate cell activation and inhibits inflammasome activation in mouse primary hepatocytes. It also down-regulated α-SMA and VGLL3 expressions and also suppressed inflammasome activation in HSC-T6 cells. VGLL3 and α-SMA expression levels were decreased in TGF-ß-stimulated HSC-T6 cells following Vgll3 knockdown. In addition, the expression levels of NLRP3 and cleaved-caspase-1 were decreased in Vgll3-silenced HSC-T6 cells. JA enhanced the inhibitory effects on Vgll3-silenced HSC-T6 cells. Finally, Vgll3 overexpression in HSC-T6 cells affected the expression levels of α-SMA, NLRP3, and cleaved-caspase-1. CONCLUSION: JA effectively modulates hepatic fibrosis by suppressing fibrogenesis and inflammation via the VGLL3/HMGB1/TLR4 axis. Therefore, JA may be a candidate therapeutic agent for the management of hepatic fibrosis. Understanding the mechanism of action of JA is a novel approach to hepatic fibrosis therapy.

Simplified panicle fertilization is applicable to japonica cultivars, but splits are preferred in indica rice for a higher paddy yield under wheat straw return.

Introduction: The panicle fertilization strategy for japonica and indica rice under wheat straw return (SR) has not been updated, especially on the elaboration of their impacts on spikelet differentiation and degeneration. This study aimed to verify the hypothesis that SR increases spikelet number by reducing spikelet degeneration and to explore the possibility of simplifying panicle fertilization. Methods: In three consecutive years, four varieties of japonica and indica rice were field-grown in Yangzhou, Jiangsu Province, China. Six panicle fertilization rates and split treatments were applied to SR and no straw return (NR) conditions. Results: The results showed that SR promoted rice yield significantly by 3.77%, and the highest yields were obtained under the T2 (split panicle fertilization at the panicle initiation (PI) and spikelet primordium differentiation (SPD) stages) and T1 (panicle fertilization only at the PI stage) treatments, for indica and japonica rice, respectively. Correlation and path analysis revealed that the number of spikelets per panicle was the most attributable to yield variation. SR significantly increased the concentration of alkali hydrolyzable N in the soil 40 days after rice transplantation, significantly increased the nitrogen accumulation per stem (NA) during the SPD-pollen mother cell meiosis (PMC) stage, and increased the brassinosteroids level in the young panicles at the PMC stage. SR also reduced the degeneration rate of spikelets (DRS) and increased the number of surviving spikelets (NSS). The dry matter accumulation per stem was more important to increasing the NA in japonica rice at the PMC stage, whereas NA was more affected by the N content than the dry matter accumulation in indica rice. In japonica rice, panicle N application once only at the PI stage combined with the N released from SR was enough to improve the plant N content, reduce the DRS, and increase the NSS. For indica rice, split application of N panicle fertilization at both the PI and SPD stages was still necessary to achieve a maximum NSS. Discussion: In conclusion, under wheat SR practice, panicle fertilization could be simplified to once in japonica rice with a significant yield increase, whereas equal splits might still be optimal for indica rice.

Genome stability of Arabidopsis atm, ku80 and rad51b mutants: somatic and transgenerational responses to stress.

DNA double-strand breaks (DSBs) can be repaired via two main mechanisms: non-homologous end joining (NHEJ) and homologous recombination (HR). Our previous work showed that exposure to abiotic stresses resulted in an increase in point mutation frequency (PMF) and homologous recombination frequency (HRF), and these changes were heritable. We hypothesized that mutants impaired in DSB recognition and repair would also be deficient in somatic and transgenerational changes in PMF and HRF. To test this hypothesis, we analyzed the genome stability of the Arabidopsis thaliana mutants deficient in ATM (communication between DNA strand break recognition and the repair machinery), KU80 (deficient in NHEJ) and RAD51B (deficient in HR repair) genes. We found that all three mutants exhibited higher levels of DSBs. Plants impaired in ATM had a lower spontaneous PMF and HRF, whereas ku80 plants had higher frequencies. Plants impaired in RAD51B had a lower HRF. HRF in wild-type, atm and rad51b plants increased in response to several abiotic stressors, whereas it did not increase in ku80 plants. The progeny of stressed wild-type and ku80 plants exhibited an increase in HRF in response to all stresses, and the increase was higher in ku80 plants. The progeny of atm plants showed an increase in HRF only when the parental generation was exposed to cold or flood, whereas the progeny of rad51b plants completely lacked a transgenerational increase in HRF. Our experiments showed that mutants impaired in the recognition and repair of DSBs exhibited changes in the efficiency of DNA repair as reflected by changes in strand breaks, point mutation and HRF. They also showed that the HR RAD51B protein and the protein ATM that recognized damaged DNA might play an important role in transgenerational changes in HRF.