Genome-wide differences in gene expression and alternative splicing in developing embryo and endosperm, and between F1 hybrids and their parental pure lines in sorghum.

KEY MESSAGE: Developing embryo and endosperm of sorghum show substantial and multifaceted differences in gene expression and alternative splicing, which are potentially relevant to heterosis. Differential regulation of gene expression and alternative splicing (AS) are major molecular mechanisms dictating plant growth and development, as well as underpinning heterosis in F1 hybrids. Here, using deep RNA-sequencing we analyzed differences in genome-wide gene expression and AS between developing embryo and endosperm, and between F1 hybrids and their pure-line parents in sorghum. We uncover dramatic differences in both gene expression and AS between embryo and endosperm with respect to gene features and functions, which are consistent with the fundamentally different biological roles of the two tissues. Accordingly, F1 hybrids showed substantial and multifaceted differences in gene expression and AS compared with their pure-line parents, again with clear tissue specificities including extents of difference, genes involved and functional enrichments. Our results provide useful transcriptome resources as well as novel insights for further elucidation of seed yield heterosis in sorghum and related crops.

Regulatory Roles of Peroxisomal Metabolic Pathways Involved in Musk Secretion in Muskrats.

In this study, we analyzed the main components of muskrat musk by gas chromatography-mass spectrometry, the results showed that muskrat musk contained fatty acids (29.32%), esters (31.89%), cholesterol (4.38%), cyclic ketones (16.31%), alcohols (6.42%) and other compounds, among which 9-octadecenoic acid accounted for 4.89%. We also analyzed the genes of the metabolic pathway in the scent gland at the transcriptomic level during musk-secreting and non-secreting seasons by RNA-seq (RNA sequencing). We detected 21 genes in the peroxisomal metabolic pathways, including PEX14(peroxin-14) and ACOX3(acyl-CoA oxidase), which exhibited significant differential expression between the musk-secreting season and the non-secreting season (p < 0.05). The RNA-seq results for these genes were validated by reverse transcription PCR(RT-PCR) for both seasons. In addition, we examined changes in the composition of muskrat musk from the glandular cells of scent glands cultured in vitro after RNA interference-mediated silencing of 2 differentially expressed genes, ACOX3 and HSD17B4(D-bifunctional protein, DBP). The 9-Octadecenoic acid content in muskrat musk decreased significantly following the silencing of ACOX3 and HSD17B4(D-bifunctional protein, DBP). These results suggest that peroxisomal metabolic pathways play important roles in the regulation of musk secretion in scent glands in the muskrat.

The chromatin remodeler ZmCHB101 impacts expression of osmotic stress-responsive genes in maize.

KEY MESSAGE: The maize chromatin remodeler ZmCHB101 plays an essential role in the osmotic stress response. ZmCHB101 controls nucleosome densities around transcription start sites of essential stress-responsive genes. Drought and osmotic stresses are recurring conditions that severely constrain crop production. Evidence accumulated in the model plant Arabidopsis thaliana suggests that core components of SWI/SNF chromatin remodeling complexes play essential roles in abiotic stress responses. However, how maize SWI/SNF chromatin remodeling complexes function in osmotic and drought stress responses remains unknown. Here we show that ZmCHB101, a homolog of A. thaliana SWI3D in maize, plays essential roles in osmotic and dehydration stress responses. ZmCHB101-RNA interference (RNAi) transgenic plants displayed osmotic, salt and drought stress-sensitive phenotypes. Genome-wide RNA-sequencing analysis revealed that ZmCHB101 impacts the transcriptional expression landscape of osmotic stress-responsive genes. Intriguingly, ZmCHB101 controls nucleosome densities around transcription start sites of essential stress-responsive genes. Furthermore, we identified that ZmCHB101 associates with RNA polymerase II (RNAPII) in vivo and is a prerequisite for the proper occupancy of RNAPII on the proximal regions of transcription start sites of stress-response genes. Taken together, our findings suggest that ZmCHB101 affects gene expression by remodeling chromatin states and controls RNAPII occupancies in maize under osmotic stress.

Sex hormones play roles in determining musk composition during the early stages of musk secretion by musk deer (Moschus berezovskii).

Musk is a secreted external hormone or information compound that is stored in musk scent glands of the males of species within the family Moschidae, such as Moschus berezovskii. The secretion of musk changes periodically during the courtship and reproduction periods, with the early stage of secretion occurring from May to July, and the maturation stage occurring from August to April of the following year. In this study, we analyzed the dynamic changes in musk components from June to April of the following year. The result showed that musk morphological character, water content, total ion chromatographic pattern, and composition undergo seasonal change. Luminescence immunoassay and radioimmunoassay analyses were performed to determine corresponding fecal hormone levels. The results showed that testosterone, estrogen, and cortisol levels in feces change on a seasonal basis, and are significantly higher in June than in other months (p < 0.01). Correlation analysis showed that the contents of four examined musk components (muscone, cyclopentadecanone, cholesterol, and cholestenol) from June to August were significantly highly negatively correlated with fecal testosterone and estradiol levels (p < 0.01). In contrast, the correlation coefficients were low or not significant from August to April of the following year. These results indicate that testosterone and estradiol may play a major role in determining musk composition during the early stage of musk secretion but not during the course of musk maturation, which suggests that musk secretion may be promoted by increases in sex hormones in June.

Polysaccharides Extracted from Rhizoma Pleionis Have Antitumor Properties In Vitro and in an H22 Mouse Hepatoma Ascites Model In Vivo.

Malignant ascites is a highly severe and intractable complication of advanced or recurrent malignant tumors that is often immunotherapy-resistant. Rhizoma Pleionis is widely used in traditional medicine as an antimicrobial and anticancer agent, but its effectiveness in treating malignant ascites is unclear. In the current study, we investigated the effect of polysaccharides isolated from Rhizoma Pleionis (PRP) on murine hepatocarcinoma H22 cells in an ascites model. We have found that the main components of PRP, that presented a relative molecular weight of 383.57 kDa, were mannose and glucose. We also found that PRP reduced the occurrence of abdominal ascites and increased survival in our mouse model. An immune response in the ascites tumor model was observed by performing a lymphocytes proliferation experiment and an E-rosette test. The ratios of CD8+ cytotoxic T cells and NK cells in the spleen were examined by flow cytometry, and the mRNA expression of Foxp3+in CD4⁺CD25⁺ (T regulatory Tregs) was measured by RT-PCR (reverse transcription-polymerase chain reaction). The levels of the cytokines TNF-α (tumor necrosis factor), VEGF (vascular endothelial growth factor), IL-2 (interleukin), and IFN-γ (interferon) in the serum and ascites supernatants were measured by ELISA. The expression of Foxp3 and Stat3 in peritoneal cells in the mouse model was measured by immunocytochemistry. The results indicated that PRP increased H22 tumor cell apoptosis in vivo by activating and enhancing the immune response. Furthermore, the effects of PRP on the proliferation of H22 cells were assessed by the CCK8 assay, Hoechest 33258, and TUNEL staining in vitro. We found that PRP suppressed the proliferation of H22 tumor cells but had no effect on BRL (Big rat liver) -3A rat hepatoma normal cells in vitro. Next, we investigated the underlying immunological mechanism by which PRP inhibits malignant ascites. PRP induced tumor cell apoptosis by inhibiting the Jak1⁻Stat3 pathway and by activating Caspase-3 and Caspase-8 to increase the Bax/Bcl-2 ratio. Collectively, our results indicate that PRP exhibits significant antitumor properties in H22 cells in vivo and in vitro, indicating that PRP may be used as a new therapeutic drug for cancer treatment.

A neural joint model for entity and relation extraction from biomedical text.

BACKGROUND: Extracting biomedical entities and their relations from text has important applications on biomedical research. Previous work primarily utilized feature-based pipeline models to process this task. Many efforts need to be made on feature engineering when feature-based models are employed. Moreover, pipeline models may suffer error propagation and are not able to utilize the interactions between subtasks. Therefore, we propose a neural joint model to extract biomedical entities as well as their relations simultaneously, and it can alleviate the problems above. RESULTS: Our model was evaluated on two tasks, i.e., the task of extracting adverse drug events between drug and disease entities, and the task of extracting resident relations between bacteria and location entities. Compared with the state-of-the-art systems in these tasks, our model improved the F1 scores of the first task by 5.1% in entity recognition and 8.0% in relation extraction, and that of the second task by 9.2% in relation extraction. CONCLUSIONS: The proposed model achieves competitive performances with less work on feature engineering. We demonstrate that the model based on neural networks is effective for biomedical entity and relation extraction. In addition, parameter sharing is an alternative method for neural models to jointly process this task. Our work can facilitate the research on biomedical text mining.

Genome-wide screen of genes imprinted in sorghum endosperm, and the roles of allelic differential cytosine methylation.

Imprinting is an epigenetic phenomenon referring to allele-biased expression of certain genes depending on their parent of origin. Accumulated evidence suggests that, while imprinting is a conserved mechanism across kingdoms, the identities of the imprinted genes are largely species-specific. Using deep RNA sequencing of endosperm 14 days after pollination in sorghum, 5683 genes (29.27% of the total 19 418 expressed genes) were found to harbor diagnostic single nucleotide polymorphisms between two parental lines. The analysis of parent-of-origin expression patterns in the endosperm of a pair of reciprocal F1 hybrids between the two sorghum lines led to identification of 101 genes with ≥ fivefold allelic expression difference in both hybrids, including 85 maternal expressed genes (MEGs) and 16 paternal expressed genes (PEGs). Thirty of these genes were previously identified as imprinted in endosperm of maize (Zea mays), rice (Oryza sativa) or Arabidopsis, while the remaining 71 genes are sorghum-specific imprinted genes relative to these three plant species. Allele-biased expression of virtually all of the 14 tested imprinted genes (nine MEGs and five PEGs) was validated by pyrosequencing using independent sources of RNA from various developmental stages and dissected parts of endosperm. Forty-six imprinted genes (30 MEGs and 16 PEGs) were assayed by quantitative RT-PCR, and the majority of them showed endosperm-specific or preferential expression relative to embryo and other tissues. DNA methylation analysis of the 5' upstream region and gene body for seven imprinted genes indicated that, while three of the four PEGs were associated with hypomethylation of maternal alleles, no MEG was associated with allele-differential methylation.

Transcription factor HAT1 is phosphorylated by BIN2 kinase and mediates brassinosteroid repressed gene expression in Arabidopsis.

Plant steroid hormones, brassinosteroids (BRs), play essential roles in modulating cell elongation, vascular differentiation, senescence and stress responses. BRs signal through plasma membrane-localized receptor and other components to modulate the BES1/BZR1 (BRI1-EMS SUPPRESSOR 1/BRASSINAZOLE RESISTANT 1) family of transcription factors that modulate thousands of target genes. Arabodopsis thaliana homeodomain-leucine zipper protein 1 (HAT1), which encodes a homeodomain-leucine zipper (HD-Zip) class II transcription factor, was identified through chromatin immunoprecipitation (ChIP) experiments as a direct target gene of BES1. Loss-of-function and gain-of-function mutants of HAT1 display altered BR responses. HAT1 and its close homolog HAT3 act redundantly, as the double mutant hat1 hat3 displayed a reduced BR response that is stronger than the single mutants alone. Moreover, hat1 hat3 enhanced the phenotype of a weak allele of the BR receptor mutant bri1 and suppressed the phenotype of constitutive BR response mutant bes1-D. These results suggest that HAT1 and HAT3 function to activate BR-mediated growth. Expression levels of several BR-repressed genes are increased in hat1 hat3 and reduced in HAT1OX, suggesting that HAT1 functions to repress the expression of a subset of BR target genes. HAT1 and BES1 bind to a conserved homeodomain binding (HB) site and BR response element (BRRE) respectively, in the promoters of some BR-repressed genes. BES1 and HAT1 interact with each other and cooperate to inhibit BR-repressed gene expression. Furthermore, HAT1 can be phosphorylated and stabilized by GSK3 (GLYCOGEN SYNTHASE KINASE 3)-like kinase BIN2 (BRASSINOSTEROID-INSENSITIVE 2), a well established negative regulator of the BR pathway. Our results thus revealed a previously unknown mechanism by which BR signaling modulates BR-repressed gene expression and coordinates plant growth.

Enhancing Video-Language Representations with Structural Spatio-Temporal Alignment.

While pre-training large-scale video-language models (VLMs) has shown remarkable potential for various downstream video-language tasks, existing VLMs can still suffer from certain commonly seen limitations, e.g., coarse-grained cross-modal aligning, under-modeling of temporal dynamics, detached video-language view. In this work, we target enhancing VLMs with a fine-grained structural spatio-temporal alignment learning method (namely Finsta). First of all, we represent the input texts and videos with fine-grained scene graph (SG) structures, both of which are further unified into a holistic SG (HSG) for bridging two modalities. Then, an SG-based framework is built, where the textual SG (TSG) is encoded with a graph Transformer, while the video dynamic SG (DSG) and the HSG are modeled with a novel recurrent graph Transformer for spatial and temporal feature propagation. A spatial-temporal Gaussian differential graph Transformer is further devised to strengthen the sense of the changes in objects across spatial and temporal dimensions. Next, based on the fine-grained structural features of TSG and DSG, we perform object-centered spatial alignment and predicate-centered temporal alignment respectively, enhancing the video-language grounding in both the spatiality and temporality. We design our method as a plug&play system, which can be integrated into existing well-trained VLMs for further representation augmentation, without training from scratch or relying on SG annotations in downstream applications. On 6 representative VL modeling tasks over 12 datasets in both standard and long-form video scenarios, Finsta consistently improves the existing 13 strong-performing VLMs persistently, and refreshes the current state-of-the-art end task performance significantly in both the fine-tuning and zero-shot settings.

ILP1 and NTR1 affect the stability of U6 snRNA during spliceosome complex disassembly in Arabidopsis.

U6 snRNA is one of the uridine-rich non-coding RNAs, abundant and stable in various cells, function as core particles in the intron-lariat spliceosome (ILS) complex. The Increased Level of Polyploidy1-1D (ILP1) and NTC-related protein 1 (NTR1), two conserved disassembly factors of the ILS complex, facilitates the disintegration of the ILS complex after completing intron splicing. The functional impairment of ILP1 and NTR1 lead to increased U6 levels, while other snRNAs comprising the ILS complex remained unaffected. We revealed that ILP1 and NTR1 had no impact on the transcription, 3' end phosphate structure or oligo(U) tail of U6 snRNA. Moreover, we uncovered that the mutation of ILP1 and NTR1 resulted in the accumulation of ILS complexes, impeding the dissociation of U6 from splicing factors, leading to an extended half-life of U6 and ultimately causing an elevation in U6 snRNA levels. Our findings broaden the understanding of the functions of ILS disassembly factors ILP1 and NTR1, and providing insights into the dynamic disassembly between U6 and ILS.

Colorable Light-Scattering Device Based on Polymer-Stabilized Ion-Doped Cholesteric Liquid Crystal and an Electrochromatic Layer.

Bistable polymer-stabilized cholesteric liquid crystal (LC) devices have been extensively researched due to their energy-saving benefits. Compared to devices with merely transparent and light-scattering states, LC devices with controlled light absorption or changeable color functions are unquestionably more intriguing. In this paper, a polymer-stabilized ion-doped cholesteric LC and an electrochromic layer are used to fabricate a colorable device which can show four operating states: transparent, light-scattering, colored transparent, and colored light-scattering. The working principle and fabrication strategy are explained in detail. Based on the dielectric response of LC, the electrohydrodynamic effect of ion-doped LC, and the redox reaction of electrochromic materials, the transparent or light-scattering state and the colored or colorless state of the device can be regulated by controlling the alternating frequency and the direction of the electric field. The display performance related to the monomer, chiral dopant, and electrochromic layer is investigated. The content of monomer and chiral dopant affects the polymer network and pitch of cholesteric LC, which then affects the driving voltages and contrast ratio. The thickness of the electrochromic layer has a significant impact on the transmittance of the device's coloring and fading states. The sample with excellent operating states is obtained by optimizing the material and the construction, which can be widely applied in smart windows and energy-saving display devices.

Effects of salt stress on ion balance and nitrogen metabolism of old and young leaves in rice (Oryza sativa L.).

BACKGROUND: It is well known that salt stress has different effects on old and young tissues. However, it remains largely unexplored whether old and young tissues have different regulatory mechanism during adaptation of plants to salt stress. The aim of this study was to investigate whether salt stress has different effects on the ion balance and nitrogen metabolism in the old and young leaves of rice, and to compare functions of both organs in rice salt tolerance. RESULTS: Rice protected young leaves from ion harm via the large accumulation of Na+ and Cl- in old leaves. The up-regulation of OsHKT1;1, OsHAK10 and OsHAK16 might contribute to accumulation of Na+ in old leaves under salt stress. In addition, lower expression of OsHKT1;5 and OsSOS1 in old leaves may decrease frequency of retrieving Na+ from old leaf cells. Under salt stress, old leaves showed higher concentration of NO3- content than young leaves. Up-regulation of OsNRT1;2, a gene coding nitrate transporter, might contribute to the accumulation of NO3- in the old leaves of salt stressed-rice. Salt stress clearly up-regulated the expression of OsGDH2 and OsGDH3 in old leaves, while strongly down-regulated expression of OsGS2 and OsFd-GOGAT in old leaves. CONCLUSIONS: The down-regulation of OsGS2 and OsFd-GOGAT in old leaves might be a harmful response to excesses of Na+ and Cl-. Under salt stress, rice might accumulate Na+ and Cl- to toxic levels in old leaves. This might influence photorespiration process, reduce NH4+ production from photorespiration, and immediately down-regulate the expression of OsGS2 and OsFd-GOGAT in old leaves of salt stressed rice. Excesses of Na+ and Cl- also might change the pathway of NH4+ assimilation in old leaves of salt stressed rice plants, weaken GOGAT/GS pathway and elevate GDH pathway.

Tissue-specific differences in cytosine methylation and their association with differential gene expression in sorghum.

It has been well established that DNA cytosine methylation plays essential regulatory roles in imprinting gene expression in endosperm, and hence normal embryonic development, in the model plant Arabidopsis (Arabidopsis thaliana). Nonetheless, the developmental role of this epigenetic marker in cereal crops remains largely unexplored. Here, we report for sorghum (Sorghum bicolor) differences in relative cytosine methylation levels and patterns at 5'-CCGG sites in seven tissues (endosperm, embryo, leaf, root, young inflorescence, anther, and ovary), and characterize a set of tissue-specific differentially methylated regions (TDMRs). We found that the most enriched TDMRs in sorghum are specific for the endosperm and are generated concomitantly but imbalanced by decrease versus increase in cytosine methylation at multiple 5'-CCGG sites across the genome. This leads to more extensive demethylation in the endosperm than in other tissues, where TDMRs are mainly tissue nonspecific rather than specific to a particular tissue. Accordingly, relative to endosperm, the other six tissues showed grossly similar levels though distinct patterns of cytosine methylation, presumably as a result of a similar extent of concomitant decrease versus increase in cytosine methylation that occurred at variable genomic loci. All four tested TDMRs were validated by bisulfite genomic sequencing. Diverse sequences were found to underlie the TDMRs, including those encoding various known-function or predicted proteins, transposable elements, and those bearing homology to putative imprinted genes in maize (Zea mays). We further found that the expression pattern of at least some genic TDMRs was correlated with its tissue-specific methylation state, implicating a developmental role of DNA methylation in regulating tissue-specific or -preferential gene expression in sorghum.

Vision-Language Navigation With Beam-Constrained Global Normalization.

Vision-language navigation (VLN) is a challenging task, which guides an agent to navigate in a realistic environment by natural language instructions. Sequence-to-sequence modeling is one of the most prospective architectures for the task, which achieves the agent navigation goal by a sequence of moving actions. The line of work has led to the state-of-the-art performance. Recently, several studies showed that the beam-search decoding during the inference can result in promising performance, as it ranks multiple candidate trajectories by scoring each trajectory as a whole. However, the trajectory-level score might be seriously biased during ranking. The score is a simple averaging of individual unit scores of the target-sequence actions, and these unit scores could be incomparable among different trajectories since they are calculated by a local discriminant classifier. To address this problem, we propose a global normalization strategy to rescale the scores at the trajectory level. Concretely, we present two global score functions to rerank all candidates in the output beam, resulting in more comparable trajectory scores. In this way, the bias problem can be greatly alleviated. We conduct experiments on the benchmark room-to-room (R2R) dataset of VLN to verify our method, and the results show that the proposed global method is effective, providing significant performance than the corresponding baselines. Our final model can achieve competitive performance on the VLN leaderboard.

Androgen plays an important role in regulating the synthesis of pheromone in the scent gland of muskrat.

The scent (musk) gland is an organ unique to muskrats and other scent-secreting animals, and the pheromones (musk) synthesized and secreted by the scent gland play a role in chemical communication among scent-secreting animals. The musk gland is synchronized with testicular developmental changes; however, little is known regarding androgen secretion from the testis and how this regulates pheromone synthesis and the secretion of scent. To investigate the effect of androgens on the synthesis of pheromones in the musk gland, we established a muskrat castration model by surgical removal of the testis, and analyzed the histomorphology, hormone concentration, gene expression, and changes in the chemical composition of the musk gland in castration and control groups by histomorphological analysis, Enzyme-Linked ImmunoSorbent Assay (ELISA), RNA sequencing (RNA-seq), and gas chromatography-mass spectrometry (GCMS). Histomorphological analysis results showed that after castration, muskrat gland cells underwent significant atrophy (P < 0.05). Hormone measurement results showed that there was a significant decrease in serum testosterone and muskrat musk testosterone (P < 0.05) after muskrat castration. Transcriptome sequencing results showed that 510 differentially expressed transcripts (DETs) were mainly enriched in fatty acid metabolism, terpenoid backbone biosynthesis, fatty acid degradation, PPAR signaling pathway, and fatty acid biosynthesis. GCMS results showed that macrocyclic ketones, steroids, fatty acids, alcohols, and esters in musk were significantly changed (P < 0.05). In conclusion, androgens were found to play an important function in the chemical communication exchange between muskrats through regulating pheromone synthesis in musk cells. This study provides a basis for understanding the mechanism of animal communication influenced by androgens.

Communication of Uncertainty about Preliminary Evidence and the Spread of Its Inferred Misinformation during the COVID-19 Pandemic-A Weibo Case Study.

The rapid spread of preliminary scientific evidence is raising concerns on its role in producing misinformation during the COVID-19 pandemic. This research investigated how the communication of uncertainty about preliminary evidence affects the spread of its inferred misinformation in a Weibo case study. In total, 3439 Weibo posts and 10,380 reposts regarding the misinformation of pets transmitting COVID-19 were analyzed. The results showed that attitude ambiguity toward the preliminary evidence and the stage when the evidence was first released with uncertainty were associated with higher numbers of likes and retweets of misinformation posts. Our study highlights the internal sources of misinformation and revisits the contextual perspective in misinformation studies.

Study of compositions of musks in different types secreted by forest musk deer (Moschus berezovskii).

Musk is a secretion of the forest musk deer (Moschus berezovskii). Normal musk is a brown solid secretion with a light fragrance. In this study, abnormal types of musk, namely, white and black musks, were discovered during the musk collection process. Researchers have long been concerned with the components of musk. Herein, GC-MS, headspace solid-phase microextraction (HS-SPME), and nonmetric multidimensional scaling (NMDS) were used to analyze the nonpolar organic components, volatile organic components, and sample similarities among different musks, respectively. Abundant steroid hormones and proteins were also found in the musk. The steroid hormone concentrations were detected using a radioimmunoassay (RIA). Proteins in the samples were hydrolyzed and the amino acids concentrations were detected. The steroid hormone and amino acid concentrations in white musk were significantly lower than in normal and black musks (p<0.05). The components were subjected to NMDS analysis to understand the differences in components among different types of musk, with the results suggesting that white musk was different from normal and black musks.

Limited tissue culture-induced mutations and linked epigenetic modifications in F hybrids of sorghum pure lines are accompanied by increased transcription of DNA methyltransferases and 5-methylcytosine glycosylases.

In plant tissue culture, developmental disturbance and mutagenic factors are involved in channeling an individual totipotent cell to an intact plant. Comparing a pair of sorghum reciprocal F(1) hybrids with their parental pure lines revealed a dramatic difference in the occurrence of both genetic and DNA methylation alterations in the respective regenerated plants. In contrast to those of the pure lines, regenerated plants of hybrids exhibit significantly enhanced genetic and epigenetic stability. The genetic changes detected by amplified fragment length polymorphism and the DNA methylation alterations detected by methylation-sensitive amplified polymorphism are intimately correlated with each other, suggesting a common mechanism underlying both kinds of instabilities. Markedly altered transcription of genes encoding four putative sorghum DNA methyltransferases and two 5-methylcytosine glycosylases with nucleotide sequences orthologous to Arabidopsis counterparts was induced by tissue culture. The steady-state transcript levels of these genes were negatively correlated with genetic and methylation alterations. A salient observation is that tissue culture-induced transcription of genes encoding DNA methyltransferases and 5-methylcytosine glycosylases in calli and/or regenerated plants of the hybrids was remarkably coordinated, but is largely uncoordinated and stochastically altered in calli and/or regenerated plants of the pure lines. We suggest that the uncoordinated regulation of expression of DNA methyltransferases and 5-methylcytosine glycosylases is a major cause of the high incidence of genetic and DNA methylation alterations in cultures of pure lines, but coordinated up-regulated expression of these enzymes in cultures of the F(1) hybrids fortified their genetic and epigenetic stability.

Tissue culture-induced variation at simple sequence repeats in sorghum (Sorghum bicolor L.) is genotype-dependent and associated with down-regulated expression of a mismatch repair gene, MLH3.

Somaclonal variation is a common phenomenon associated with plant tissue culture. Microsatellites or simple sequence repeats (SSRs) are ubiquitous components of eukaryotic genomes, and are intrinsically unstable under various stress conditions including tissue culture. Here, we assessed genetic stability of a set of 29 mapped SSR loci in calli and regenerated plants derived from a pair of reciprocal sorghum inter-strain F1 hybrids and their pure line parents. We further measured the steady-state transcripts of a set of nine mismatch repair (MMR)-encoding genes and a DEMETER (DME), a DNA glycosylase domain protein-encoding gene in these lines, and tested for a possible relationship between altered expression of a given MMR or DME gene and the SSR variations. We found that SSR variations occurred in calli and regenerated plants of both the studied pure lines though at sharply different frequencies (20.7 vs. 6.9%), but no variation was detected in calli and regenerated plants of the pair of F1 hybrids. Compared with the donor seed plants, markedly altered expression of all nine studied MMR genes and the DME gene was observed in calli, and more conspicuously, in the regenerated plants. However, only one gene, i.e., MLH3, showed an altered expression pattern that is genotype specific and significantly correlated with the occurrence of SSR instability.

A False Trail to Follow: Differential Effects of the Facial Feedback Signals From the Upper and Lower Face on the Recognition of Micro-Expressions.

Micro-expressions, as fleeting facial expressions, are very important for judging people's true emotions, thus can provide an essential behavioral clue for lie and dangerous demeanor detection. From embodied accounts of cognition, we derived a novel hypothesis that facial feedback from upper and lower facial regions has differential effects on micro-expression recognition. This hypothesis was tested and supported across three studies. Specifically, the results of Study 1 showed that people became better judges of intense micro-expressions with a duration of 450 ms when the facial feedback from upper face was enhanced via a restricting gel. Additional results of Study 2 showed that the recognition accuracy of subtle micro-expressions was significantly impaired under all duration conditions (50, 150, 333, and 450 ms) when facial feedback from lower face was enhanced. In addition, the results of Study 3 also revealed that blocking the facial feedback of lower face, significantly boosted the recognition accuracy of subtle and intense micro-expressions under all duration conditions (150 and 450 ms). Together, these results highlight the role of facial feedback in judging the subtle movements of micro-expressions.