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Biology subjects

Sun, L.

Publications and source records attributed to Sun, L..

At least 181 records · Page 10Linked to original sources

TopDIA: A Software Tool for Top-Down Data-Independent Acquisition Proteomics

Top-down mass spectrometry is widely used for proteoform identification, characterization, and quantification owing to its ability to analyze intact proteoforms. In the last decade, top-down proteomics has been dominated by top-down data-dependent acquisition mass spectrometry (TD-DDA-MS), and top-down data-independent acquisition mass spectrometry (TD-DIA-MS) has not been well studied. While TD-DIA-MS produces complex multiplexed tandem mass spectrometry (MS/MS) spectra, which are challenging to confidently identify, it selects more precursor ions for MS/MS analysis and has the potential to increase proteoform identifications compared with TD-DDA-MS. Here we present TopDIA, the first software tool for proteoform identification by TD-DIA-MS. It generates demultiplexed pseudo MS/MS spectra from TD-DIA-MS data and then searches the pseudo MS/MS spectra against a protein sequence database for proteoform identification. We compared the performance of TD-DDA-MS and TD-DIA-MS using Escherichia coli K-12 MG1655 cells and demonstrated that TD-DIA-MS with TopDIA increased proteoform and protein identifications compared with TD-DDA-MS.

bioinformatics↗

Negative regulation of APC/C activation by MAPK-mediated attenuation of Cdc20Slp1 under stress

Mitotic anaphase onset is a key cellular process tightly regulated by multiple kinases. The involvement of mitogen-activated protein kinases (MAPKs) in this process has been established in Xenopus egg extracts. However, the detailed regulatory cascade remains elusive, and also it is unknown whether the MAPKs-dependent mitotic regulation is evolutionarily conserved in the single cell eukaryotic organism such as fission yeast (Schizosaccharomyces pombe). Here we show that two MAPKs in S. pombe indeed act in concert to restrain anaphase-promoting complex/cyclosome (APC/C) activity upon activation of the spindle assembly checkpoint (SAC). One MAPK, Pmk1, binds and phosphorylates Slp1Cdc20, the co-activator of APC/C. Phosphorylation of Slp1Cdc20 by Pmk1, but not by Cdk1, promotes its subsequent ubiquitylation and degradation. Intriguingly, Pmk1-mediated phosphorylation event is also required to sustain SAC under environmental stress. Thus, our study establishes a new underlying molecular mechanism of negative regulation of APC/C by MAPK upon stress stimuli, and provides an unappreciated framework for regulation of anaphase entry in eukaryotic cells. One-sentence summaryInhibitory effect on the activation of anaphase promoting complex/cyclosome (APC/C) by MAPK Pmk1

cell biology↗

Biologically informed machine learning modeling of immune cells to reveal physiological and pathological aging process

The immune system undergoes progressive functional remodeling from neonatal stages to old age. Therefore, understanding how aging shapes immune cell function is vital for precise treatment of patients at different life stages. Here, we constructed the first transcriptomic atlas of immune cells encompassing human lifespan, ranging from newborns to supercentenarians, and comprehensively examined gene expression signatures involving cell signaling, metabolism, differentiation, and functions in all cell types to investigate immune aging changes. By comparing immune cell composition among different age groups, HLA highly expressing NK cells and CD83 positive B cells were identified with high percentages exclusively in the teenager (Tg) group, whereas CD4_CTL precursors were exclusively enriched in the supercentenarian (Sc) group. Notably, we found that the biological age (BA) of pediatric COVID-19 patients with multisystem inflammatory syndrome accelerated aging according to their chronological age (CA). Besides, we proved that inflammatory shift-myeloid abundance and signature correlate with the progression of complications in Kawasaki disease (KD). Finally, based on those age-related immune cell compositions, we developed a novel BA prediction model, PHARE (https://xiazlab.org/phare/), which applies to both scRNA-seq and bulk RNA-seq data. Overall, our study revealed changes in immune cell proportions and function associated with aging, both in health and disease, and provided a novel tool for successfully capturing features that accelerate or delay aging.

immunology↗

Ribosome biogenesis factor AtRRB1 confers pollen heat stress tolerance in Arabidopsis

The plant male reproductive system is very sensitive to high temperature stress leading to a reduction in fertility. Damage caused by heat stress is restored by the activation of transcription and the synthesis of chaperones that regulate the heat stress response. Here we report that AtRRB1 is a homolog of the yeast ribosome chaperone protein Rrb1p. AtRRB1 is an essential gene and a T-DNA insertion in the coding region impairs male and female gametogenesis. The heterozygous rrb1-1 mutant shows decreased expression of AtRRB1 and increased transcription of the 60S ribosome proteins RPL3B and RPL4, in line with a chaperone role of AtRRB1 in ribosome biogenesis. Embryo sac development across ovules of a single pistil occurs uncoordinated and about half of the ovules abort. Half of rrb1-1 pollen is substantially smaller and produce shorter pollen tubes than WT pollen. In contrast to the Col-0 pollen, smaller pollen is overly sensitivity to high temperature (24h at 32{degrees}C) treatment, specifically during the early bicellular microspore development stage. Heat stressed rrb1-1 bicellular microspores accumulated excessively rough endoplasmic reticulum stacks, suggesting that loss of AtRRB1 activity causes an arrest in ER associated protein biosynthesis. These findings support a critical requirement for ribosome biogenesis and protein synthesis in bicellular microspores to recover from high temperature stress.

plant biology↗

Mutation of GmDMP genes triggers haploid induction in soybean

The development of homozygous lines is a key step in plant breeding and production. Generally, homozygous lines can be obtained through traditional time-consuming way of several generations selfing or through a way of doubled haploid (DH) technology, which has obvious advantages to accelerate breeding. However, no effective haploid production system so far has been established in soybean. Here we show that mutations of the soybean GmDMP1 and GmDMP2 genes can be used to induce haploid with an average haploid induction rate of 0.61%. We also found that 22.9% of soybean haploids can produce seeds through spontaneous chromosome doubling. Those findings laid a solid foundation for establishing DH technology in soybean, which will accelerate soybean breeding.

genetics↗

BRD8 guards the pluripotent state by sensing and maintaining histone acetylation

Epigenetic control of cell fates is a critical determinant to maintain cell type stability and permissive differentiation. However, the epigenetic control mechanisms are not well understood. Here, we show that the histone acetyltransferase reader protein BRD8 impairs the conversion of primed mouse EpiSCs (epiblast stem cells) to naive mouse ESCs (embryonic stem cells). BRD8 works by maintaining histone acetylation on promoters and transcribed gene bodies. BRD8 is responsible for maintaining open chromatin at somatic genes, and histone acetylation at naive-specific genes. When Brd8 expression was reduced, chromatin accessibility was unchanged, but histone acetylation at primed-specific genes was reduced. Conversely, naive-specific genes had reduced repressive chromatin marks, and acquired accessible chromatin more rapidly during the cell type conversion. We show that this process requires active histone deacetylation to promote the conversion of primed to naive. Our data supports a model for BRD8 reading histone acetylation to accurately localize the genome-wide binding of the histone acetyltransferase KAT5. Overall, this study shows how the reading of the histone acetylation state by BRD8 maintains cell type stability. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=81 SRC="FIGDIR/small/585857v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@199139forg.highwire.dtl.DTLVardef@d735c6org.highwire.dtl.DTLVardef@10b6e15org.highwire.dtl.DTLVardef@16863cf_HPS_FORMAT_FIGEXP M_FIG C_FIG Key findingsO_LIBRD8 blocks the primed-to-naive transition. C_LIO_LIReduced Brd8 promoted the suppression of somatic and primed genes through reduced chromatin repression. C_LIO_LIReduced Brd8 enabled the accelerated activation of naive-specific genes by opening chromatin. C_LIO_LIBRD8 anchors the histone acetyltransferase KAT5 to acetylated genomic loci. C_LI

cell biology↗

Normative growth modeling of brain morphology reveals neuroanatomical heterogeneity and biological subtypes in children with ADHD

BackgroundNeuroimaging studies suggest substantial individual heterogeneity in brain phenotypes in attention-deficit/hyperactivity disorder (ADHD). However, how these individual-level brain phenotypes contribute to the identification of ADHD biotypes and whether these biotypes have different treatment outcomes and neurobiological underpinnings remain largely unknown. MethodsWe collected multisite, high-quality structural magnetic resonance imaging data from 1,006 children aged 6-14 years, including 351 children with ADHD and 655 typically developing children. Normative growth models of cortical thickness were established for 219 regions in the typically developing children. Individual-level deviations from these normal references were quantified and clustered to identify ADHD biotypes. We validated the replicability and generalizability of the ADHD biotypes using two independent datasets and evaluated the associations of the biotypes with symptomatic, cognitive, and gene expression profiles, as well as follow-up treatment outcomes. FindingsNo more than 10% of children with ADHD had extreme deviations in cortical thickness in a single region, suggesting high heterogeneity among individuals with ADHD. On the basis of the brain deviation maps, we discovered two robust ADHD biotypes, an infra-normal subtype with cortical thinning associated with ADHD symptoms and a supranormal subtype with cortical thickening associated with cognition. Patients with the infra-normal subtype responded better to methylphenidate than to atomoxetine, although both subtypes showed treatment efficacy. Brain deviations in the infra-normal subtype were explained by the expression levels of genes enriched in presynaptic and axonal development and polygenic risk of ADHD. InterpretationWe identified anatomically distinct, clinically valuable, and biologically informed ADHD subtypes, providing insight into the neurobiological basis of clinical heterogeneity and facilitating a personalized medication strategy for ADHD patients. Panel: Research in contextO_ST_ABSEvidence before this studyC_ST_ABSSubstantial individual heterogeneity in brain phenotypes in attention-deficit/hyperactivity disorder (ADHD) motivates the need to discover homogeneous biotypes. We searched PubMed for research articles on ADHD biotypes using brain MRI published before December 1, 2023, using the search terms ((attention deficit hyperactivity disorder [Title/Abstract]) OR (ADHD [Title/Abstract])) AND ((subtypes [Title/Abstract]) OR (subgroups [Title/Abstract]) OR (subtyping [Title/Abstract])) AND ((MRI [Title/Abstract]) OR (neuroimaging [Title/Abstract]) OR (brain [Title/Abstract])) without language restrictions. Of the eight included studies, two identified ADHD biotypes using structural morphology, four used functional activity, and two used multimodal features. However, none of these studies considered the developmental effect of the brain phenotypes, examined treatment response, or investigated the genetic correlates of the biotypes. Added value of this studyThis study is the first to use individualized brain measures extracted from normative models to investigate ADHD biotypes in a large sample of more than 1,000 children. We identified two reproducible ADHD biotypes, characterized by distinct symptomatic, cognitive, and gene expression profiles, as well as differential treatment responses. This study advances our understanding of the neurobiological basis underlying the clinical heterogeneity of ADHD and highlights the critical need to discover ADHD biotypes using an unbiased and individualized approach. Implications of all the available evidenceThis study revealed remarkable neuroanatomical heterogeneity in ADHD patients and identified anatomically distinct, clinically valuable, and biologically informed ADHD biotypes. Our findings have potential value for the investigation of data-driven biotypes to evaluate treatment efficacy and facilitate personalized treatment. We also highlight the need for future studies to move beyond the understanding of ADHD solely based on the "average patient" perspective.

neuroscience↗

Deep learning based genomic breeding of pest-resistant grapevine

Crop pests have profoundly deleterious effects on crop yield and food security. However, conventional pest control depends heavily on the utilization of insecticides, which develops strong pesticide resistance and concerns of food safety. Crop and their wild relatives display diverse levels of pest resistance, indicating the feasibility for breeding of pest-resistant crop varieties. In this study, we integrate deep learning (DL)/machine learning (ML) algorithms, plant phenomics and whole genome sequencing (WGS) data to conduct genomic selection (GS) of pest-resistance in grapevine. We employ deep convolutional neural networks (DCNN) to accurately calculate the severity of damage by pests on grape leaves, which achieves a classification accuracy of 95.3% (Visual Geometry Group 16, VGG16, for binary trait) and a correlation coefficient of 0.94 in regression analysis (DCNN with Pest Damage Score, DCNN-PDS, for continuous trait). We apply DL models to predict and integrate phenotype (both binary and continuous) along with WGS data from 231 grape accessions, conducting Genome-Wide Association Studies (GWAS). This analysis detects a total of 69 QTLs, encompassing 139 candidate genes involved in pathways associated with pest resistance, including jasmonic acid (JA), salicylic acid (SA), ethylene, and other related pathways. Furthermore, through the combination with transcriptome data, we identify specific pest-resistant genes, such as ACA12 and CRK3, which play distinct roles in resisting herbivore attacks. Machine learning-based GS demonstrates a high accuracy (95.7%) and a strong correlation (0.90) in predicting the leaf area damaged by pests as binary and continuous traits in grapevine, respectively. In general, our study highlights the power of DL/ML in plant phenomics and GS, facilitating genomic breeding of pest-resistant grapevine.

plant biology↗

Orthogonal IMiD-Degron Pairs Induce Selective Protein Degradation in Cells

Immunomodulatory imide drugs (IMiDs) including thalidomide, lenalidomide, and pomalidomide, can be used to induce degradation of a protein of interest that is fused to a short zinc finger (ZF) degron motif. These IMiDs, however, also induce degradation of endogenous neosubstrates, including IKZF1 and IKZF3. To improve degradation selectivity, we took a bump-and-hole approach to design and screen bumped IMiD analogs against 8380 ZF mutants. This yielded a bumped IMiD analog that induces efficient degradation of a mutant ZF degron, while not affecting other cellular proteins, including IKZF1 and IKZF3. In proof-of-concept studies, this system was applied to induce efficient degradation of TRIM28, a disease-relevant protein with no known small molecule binders. We anticipate that this system will make a valuable addition to the current arsenal of degron systems for use in target validation. One-Sentence SummaryEngineered zinc-finger-based degrons enable targeted protein degradation induced by selective molecular glues.

biochemistry↗

HemaCisDB: An Interactive Database for Analyzing Cis-Regulatory Elements Across Hematopoietic Malignancies

Noncoding cis-regulatory elements (CREs), such as transcriptional enhancers, are key regulators of gene expression programs. Accessible chromatin and H3K27ac are well-recognized markers for CREs associated with their biological function. Deregulation of CREs is commonly found in hematopoietic malignancies yet the extent to which CRE dysfunction contributes to pathophysiology remains incompletely understood. Here, we developed HemaCisDB, an interactive, comprehensive, and centralized online resource for CRE characterization across hematopoietic malignancies, serving as a useful resource for investigating the pathological roles of CREs in blood disorders. Currently, we collected 922 ATAC-seq, 190 DNase-seq, and 531 H3K27ac ChIP-seq datasets from patient samples and cell lines across different myeloid and lymphoid neoplasms. HemaCisDB provides comprehensive quality control metrics to assess ATAC-seq, DNase-seq, and H3K27ac ChIP-seq data quality. The analytic modules in HemaCisDB include transcription factor (TF) footprinting inference, super-enhancer identification, and core transcriptional regulatory circuitry analysis. Moreover, HemaCisDB also enables the study of TF binding dynamics by comparing TF footprints across different disease types or conditions via web-based interactive analysis. Together, HemaCisDB provides an interactive platform for CRE characterization to facilitate mechanistic studies of transcriptional regulation in hematopoietic malignancies. HemaCisDB is available at https://hemacisdb.chinablood.com.cn/.

bioinformatics↗

Deep Plasma Proteome Profiling by Modulating Single Nanoparticle Protein Corona with Small Molecules

The protein corona, a dynamic biomolecular layer that forms on nanoparticle (NP) surfaces upon exposure to biological fluids is emerging as a valuable diagnostic tool for improving plasma proteome coverage analyzed by liquid chromatography-mass spectrometry (LC-MS/MS). Here, we show that spiking small molecules, including metabolites, lipids, vitamins, and nutrients (namely, glucose, triglyceride, diglycerol, phosphatidylcholine, phosphatidylethanolamine, L--phosphatidylinositol, inosine 5'-monophosphate, and B complex), into plasma can induce diverse protein corona patterns on otherwise identical NPs, significantly enhancing the depth of plasma proteome profiling. The protein coronas on polystyrene NPs when exposed to plasma treated with an array of small molecules (n=10) allowed for detection of 1793 proteins marking an 8.25-fold increase in the number of quantified proteins compared to plasma alone (218 proteins) and a 2.63-fold increase relative to the untreated protein corona (681 proteins). Furthermore, we discovered that adding 1000 {micro}g/ml phosphatidylcholine could singularly enable the detection of 897 proteins. At this specific concentration, phosphatidylcholine selectively depleted the four most abundant plasma proteins, including albumin, thus reducing the dynamic range of plasma proteome and enabling the detection of proteins with lower abundance. By employing an optimized data-independent acquisition (DIA) approach, the inclusion of phosphatidylcholine led to the detection of 1436 proteins in a single plasma sample. Our molecular dynamic results revealed that phosphatidylcholine interacts with albumin via hydrophobic interactions, h-bonds, and water-bridges. Addition of phosphatidylcholine also enabled the detection of 337 additional proteoforms compared to untreated protein corona using a top-down proteomics approach. These significant achievements are made utilizing only a single NP type and one small molecule to analyze a single plasma sample, setting a new standard in plasma proteome profiling. Given the critical role of plasma proteomics in biomarker discovery and disease monitoring, we anticipate widespread adoption of this methodology for identification and clinical translation of proteomic biomarkers into FDA approved diagnostics.

bioengineering↗

Ultraviolet attenuates centromere-mediated meiotic genome stability and alters gametophytic ploidy consistency in flowering plants

Ultraviolet (UV) radiation influences development and genome stability in organisms; however, its impacts on meiosis, a special cell division essential for the delivery of genetic information over generations in eukaryotes, remain not yet elucidated. In this study, we demonstrate that UV attenuates the centromere-mediated meiotic chromosome stability and induces unreduced gametes in Arabidopsis thaliana. We show that UV reduces crossover (CO) rate but does not interfere with meiotic chromosome integrity. Functional centromere-specific histone 3 (CENH3) is required for the obligate CO formation, and plays a role in protection of homolog synapsis and sister-chromatid cohesion under UV stress. Moreover, UV specifically alters the orientation and organization of spindles and phragmoplasts at meiosis II, resulting in meiotic restitution and unreduced gametes. Further, we determine that UV-induced meiotic restitution does not rely on the UV Resistance Locus8-mediated UV perception and the Tapetal Development and Function1- and Aborted Microspores-dependent tapetum development, but occurs possibly via impacted JASON function and downregulated Parallel Spindle1. This study sheds light on the impacts of UV on meiotic genome stability and gametophytic ploidy consistency, which thus may influence genome evolution in flowering plants.

plant biology↗

Genome-wide CRISPR screen identifies AC9 as a key regulator of ER calcium homeostasis involved in neuronal differentiation.

Endoplasmic reticulum (ER) calcium (Ca2+) homeostasis is essential for maintaining normal cellular physiological functions. Its disturbance is strongly linked to the onset and progression of human diseases, including cancer, developmental defects, and neurodegenerative disorders. The lack of sensitive ratiometric ER Ca2+ indicators, nevertheless, hinders systematic investigation of ER Ca2+ modulators and the underlying mechanisms. Capitalizing on two ultra-sensitive ER Ca2+ indicators and CRISPR-based genome-wide screening, we identified a set of proteins capable of reducing the ER Ca2+ content. Further comparative analysis and qPCR validation pinpointed adenylate cyclase 9 (AC9), which is upregulated during neuronal differentiation, as a key ER-Ca2+-reducing regulator. Mechanistically, AC9-mediated production of cAMP is not essential for its ability to reduce ER Ca2+ content. Instead, AC9 inhibits store operated calcium entry (SOCE) by acting on Orai1, ultimately causing attenuation of ER Ca2+ level. More physiologically relevant, upregulation of AC9 in neurons is essential for reducing ER Ca2+ levels during Drosophila brain development. Collectively, this study lays a solid groundwork for further in-depth exploration of the regulatory mechanisms dictating ER Ca2+ homeostasis during neuronal differentiation and brain development.

cell biology↗

Chromosome segment scanning for gain- or loss-of-function screening (CHASING) and its application in metabolic engineering

Constructing a library of thousands of single-gene knockout or interference strains is a powerful tool to understand the relation between genotype and phenotype, but it is labor and cost intensive. Powered by the computer-aided gene annotation and functional grouping of non-essential genes, we showed that targeting a single gene directly to a specific observed phenotype could be quickly achieved for a specific microorganism via constructing a library of strains containing single chromosome-segment-deletion per strain. As a proof-of-concept, a genome-scale library consisting of 70 chromosome-segment-deletion strains for B. subtilis was constructed by CRISPR-based methods and strains with six loss-of- and gain-of-function phenotypes were screened out. To facilitate the rapid genotyping, we developed a web tool to visualize the potential targets of each chromosome segment associated with a particular function, successfully identifying the genes for valuable representative phenotypes. To apply the library to metabolic engineering, the hosts with improved production capacity of acetoin and lycopene were screened in the presence of pathway genes. This work demonstrated the significance of our strategy of chromosome segment scanning for gain- or loss-of-function screening (CHASING) on functional genomics investigation, robust chassis engineering, and chemical overproduction. O_FIG O_LINKSMALLFIG WIDTH=159 HEIGHT=200 SRC="FIGDIR/small/578163v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@19b4938org.highwire.dtl.DTLVardef@1e41d2eorg.highwire.dtl.DTLVardef@137d4b3org.highwire.dtl.DTLVardef@6d4bfc_HPS_FORMAT_FIGEXP M_FIG TOC C_FIG

bioengineering↗

An endothelial SOX18-mevalonate pathway axis enables repurposing of statins for infantile hemangioma

Infantile hemangioma (IH) is the most common tumor in children and a paradigm for pathological vasculogenesis, angiogenesis and regression. Propranolol is the mainstay of treatment for IH. It inhibits hemangioma vessel formation via a {beta}-adrenergic receptor independent off-target effect of its R(+) enantiomer on the endothelial specific transcription factor sex-determining region Y (SRY) box transcription factor 18 (SOX18). Transcriptomic profiling of patient-derived hemangioma stem cells uncovered the mevalonate pathway (MVP) as a target of R(+) propranolol. Loss of SOX18 function confirmed R(+) propranolol mode of action on the MVP. Functional validation in preclinical IH models revealed that statins - targeting the MVP - are potent inhibitors of hemangioma vessel formation. We propose a novel SOX18-MVP-axis as a central regulator of IH pathogenesis and suggest statin repurposing to treat IH. Our findings reveal novel pleiotropic effects of beta-blockers and statins acting on the SOX18-MVP axis to disable an endothelial specific program in IH, which may impact other scenarios involving pathological vasculogenesis and angiogenesis. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=135 SRC="FIGDIR/small/577829v2_ufig1.gif" ALT="Figure 1"> View larger version (21K): org.highwire.dtl.DTLVardef@f02b2corg.highwire.dtl.DTLVardef@1a2790forg.highwire.dtl.DTLVardef@1ba0318org.highwire.dtl.DTLVardef@1213522_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

Transcriptomic and epigenetic responses shed light on soybean resistance to Phytophthora sansomeana

Phytophthora root rot caused by oomycete pathogens in the Phytophthora genus poses a significant threat to soybean productivity. While resistance mechanisms against Phytophthora sojae have been extensively studied in soybean, the molecular basis underlying immune responses to Phytophthora sansomeana remains unclear. We investigated transcriptomic and epigenetic responses of two resistant (Colfax and NE2701) and two susceptible (Williams 82 and Senaki) soybean lines at four time points (2, 4, 8, and 16 hours post inoculation, hpi) after P. sansomeana inoculation. Comparative transcriptomic analyses revealed a greater number of differentially expressed genes (DEGs) upon pathogen inoculation in resistant lines, particularly at 8 and 16 hpi, predominantly associated with ethylene and reactive oxygen species-mediated defense pathways. Moreover, DE transposons were predominantly up-regulated after inoculation and enriched near genes in Colfax. A long non-coding RNA (lncRNA) within the mapped region of the resistance gene exhibited exclusive up-regulation in the resistant lines after inoculation, potentially regulating two flanking LURP-one-related genes. Furthermore, DNA methylation analysis revealed increased CHH methylation levels in lncRNAs after inoculation, with delayed responses in Colfax compared to Williams 82. Overall, our results provide comprehensive insights into soybean responses to P. sansomeana, highlighting potential roles of lncRNAs and epigenetic regulation in plant defense.

plant biology↗

The investigation of dysregulated visual perceptual organization in adults with autism spectrum disorders with phase-amplitude coupling and directed connectivity

Phase-amplitude coupling (PAC) has been used as a powerful tool to understand the mechanism underlying neural binding by investigating neural synchrony across different frequency bands. This study examined the possibility that dysregulated alpha-gamma modulation may be crucially involved in aberrant brain functioning in autism spectrum disorder (ASD). Magnetoencephalographic data were recorded from 13 adult participants with ASD and 16 controls. The time-coursed sources averaged over a primary visual area 1 and fusiform gyrus area were reconstructed with the minimum-norm estimate method. The alpha-gamma PAC was further calculated based on these sources. The statistical analysis was implemented based on the PAC and directed asymmetry index. The results showed the hyper-activity coupling for ASD at the no-face condition and revealed the importance of alpha-gamma phase modulation in detecting a face. Our data provides novel evidence for the role of the alpha-gamma PAC and suggests that the globe connectivity may be more critical during visual perception.

neuroscience↗

SKSR1 identified as key virulence factor in Cryptosporidium by genetic crossing

Cryptosporidium parvum is a major cause of severe diarrhea. Although isolates of this zoonotic parasite exhibit significant differences in infectivity and virulence, the genetic determinants for these traits are not clear. In this study, we used classical genetics to cross two C. parvum isolates of different virulence and used bulked segregant analysis of whole-genome sequence data from the progeny to identify quantitative trait loci (QTL) associated with Cryptosporidium infectivity and virulence. Of the 26 genes in three QTL, two had loss-of-function mutations in the low-virulence isolates. Deletion of the SKSR1 gene or expression of the frame-shift mutant sequence reduced the pathogenicity of infection in vivo. SKSR1 is a polymorphic secretory protein expressed in small granules and secreted into the parasite-host interface. These results demonstrate that SKSR1 is an important virulence factor in Cryptosporidium, and suggest that this extended family may contribute to pathogenesis.

microbiology↗