Assessing the efficiency of eligibility criteria for low-dose computed tomography lung screening in China according to current guidelines.

BACKGROUND: Evidence from observational studies indicates that lung cancer screening (LCS) guidelines with high rates of lung cancer (LC) underdiagnosis, and although current screening guidelines have been updated and eligibility criteria for screening have been expanded, there are no studies comparing the efficiency of LCS guidelines in Chinese population. METHODS: Between 2005 and 2022, 31,394 asymptomatic individuals were screened using low-dose computed tomography (LDCT) at our institution. Demographic data and relevant LC risk factors were collected. The efficiency of the LCS for each guideline criteria was expressed as the efficiency ratio (ER). The inclusion rates, eligibility rates, LC detection rates, and ER based on the different eligibility criteria of the four guidelines were comparatively analyzed. The four guidelines were as follows: China guideline for the screening and early detection of lung cancer (CGSL), the National Comprehensive Cancer Network (NCCN), the United States Preventive Services Task Force (USPSTF), and International Early Lung Cancer Action Program (I-ELCAP). RESULTS: Of 31,394 participants, 298 (155 women, 143 men) were diagnosed with LC. For CGSL, NCCN, USPSTF, and I-ELCAP guidelines, the eligibility rates for guidelines were 13.92%, 6.97%, 6.81%, and 53.46%; ERe for eligibility criteria were 1.46%, 1.64%, 1.51%, and 1.13%, respectively; and for the inclusion rates, they were 19.0%, 9.5%, 9.3%, and 73.0%, respectively. LCs which met the screening criteria of CGSL, NCCN, USPSTF, and I-ELCAP guidelines were 29.2%, 16.4%, 14.8%, and 86.6%, respectively. The age and smoking criteria for CGSL were stricter, hence resulting in lower rates of LC meeting the screening criteria. The CGSL, NCCN, and USPSTF guidelines showed the highest underdiagnosis in the 45-49 age group (17.4%), while the I-ELCAP guideline displayed the highest missed diagnosis rate (3.0%) in the 35-39 age group. Males and females significantly differed in eligibility based on the criteria of the four guidelines (P < 0.001). CONCLUSIONS: The I-ELCAP guideline has the highest eligibility rate for both males and females. But its actual efficiency ratio for those deemed eligible by the guideline was the lowest. Whereas the NCCN guideline has the highest ERe value for those deemed eligible by the guideline.

Sensitive fluorescence ELISA for the detection of zearalenone based on self-assembly DNA nanocomposites and copper nanoclusters.

Zearalenone (ZEN), produced by Fusarium species, is a potential risk to human health. Traditional enzyme-linked immunosorbent assay (ELISA) is restricted due to low sensitivity for the detection of ZEN. Herein, enzyme nanocomposites (ALP-SA-Bio-ssDNA, ASBD) were prepared with the self-assembly strategy based on streptavidin-labeled alkaline phosphatase (SA-ALP) and dual-biotinylated ssDNA (B2-ssDNA). The enzyme nanocomposites improved the loading amount of ALP and catalyzed more ascorbic acid 2-phosphate to generate ascorbic acid (AA). Subsequently, Cu2+ could be reduced to copper nanoclusters (CuNCs) having strong fluorescence signal by AA with poly T. Benefiting from the high enzyme load of nanocomposites and the strong signal of CuNCs, the fluorescence ELISA was successfully established for the detection of ZEN. The proposed method exhibited lower limit of detection (0.26 ng mL-1) than traditional ELISA (1.55 ng mL-1). The recovery rates ranged from 92.00% to 108.38% (coefficient of variation < 9.50%) for the detection of zearalenone in corn and wheat samples. In addition, the proposed method exhibited no cross reaction with four other mycotoxins. This proposed method could be used in trace detection for food safety.

Quantitative morphometric changes in vascular mild cognitive impairment patients: early diagnosis of dementia.

Vascular mild cognitive impairment (VMCI) is an early and reversible stage of dementia. Volume differences in regional gray matter may reveal the development and prognosis of VMCI. This study selected 2 of the most common types of VMCI, namely, periventricular white matter hyperintensities (PWMH, n = 14) and strategic single infarctions (SSI, n = 10), and used the voxel-based morphometry method to quantify their morphological characteristics. Meanwhile, age- and sex-matched healthy volunteers were included (n = 16). All the participants were neuropsychologically tested to characterize their cognitive function and underwent whole-brain magnetic resonance imaging scanning. Our results showed that the volumes of the bilateral temporal lobes and bilateral frontal gray matter were obviously diminished in the PWMH group. The atrophy volume difference was 4,086 voxels in the left temporal lobe, 4,154 voxels in the right temporal lobe, 1,718 voxels in the left frontal lobe, and 1,141 voxels in the right frontal lobe (P ≤ 0.001). Moreover, the characteristics of the gray matter atrophy associated with the PWMH were more similar to those associated with Alzheimer's disease than SSI, which further revealed the susceptibility for escalation from PWMH to dementia. In conclusion, PWMH patients and SSI patients have different morphological characteristics, which explain the different prognoses of VMCI.

Rac1 promotes the reprogramming of glucose metabolism and the growth of colon cancer cells through upregulating SOX9.

Metabolic reprogramming is the survival rule of tumor cells, and tumor cells can meet their high metabolic requirements by changing the energy metabolism mode. Metabolic reprogramming of tumor cells is an important biochemical basis of tumor malignant phenotypes. Ras-related C3 botulinum toxin substrate 1 (Rac1) is abnormally expressed in a variety of tumors and plays an important role in the proliferation, invasion, and migration of tumor cells. However, the role of Rac1 in tumor metabolic reprogramming is still unclear. Herein, we revealed that Rac1 was highly expressed in colon cancer tissues and cell lines. Rac1 promotes the proliferation, migration, and invasion of colon cancer cells by upregulating SOX9, which as a transcription factor can directly bind to the promoters of HK2 and G6PD genes and regulate their transcriptional activity. Rac1 upregulates the expression of SOX9 through the PI3K/AKT signaling pathway. Moreover, Rac1 can promote glycolysis and the activation of the pentose phosphate pathway in colon cancer cells by mediating the axis of SOX9/HK2/G6PD. These findings reveal novel regulatory axes involving Rac1/SOX9/HK2/G6PD in the development and progression of colon cancer, providing novel promising therapeutic targets.

LPLUNC1 reduces glycolysis in nasopharyngeal carcinoma cells through the PHB1-p53/c-Myc axis.

Cancer cells prefer glycolysis to support their proliferation. Our previous studies have shown that the long palate, lung, and nasal epithelial cell clone 1 (LPLUNC1) can upregulate prohibitin 1 (PHB1) expression to inhibit the proliferation of nasopharyngeal carcinoma (NPC) cells. Given that PHB1 is an important regulator of cell energy metabolism, we explored whether and how LPLUNC1 regulated glucose glycolysis in NPC cells. LPLUNC1 or PHB1 overexpression decreased glycolysis and increased oxidative phosphorylation (OXPHOS)-related protein expression in NPC cells, promoting phosphorylated PHB1 nuclear translocation through 14-3-3σ. LPLUNC1 overexpression also increased p53 but decreased c-Myc expression in NPC cells, which were crucial for the decrease in glycolysis and increase in OXPHOS-related protein expression induced by LPLUNC1 overexpression. Finally, we found that treatment with all-trans retinoic acid (ATRA) reduced the viability and clonogenicity of NPC cells, decreased glycolysis, and increased OXPHOS-related protein expression by enhancing LPLUNC1 expression in NPC cells. Therefore, the LPLUNC1-PHB1-p53/c-Myc axis decreased glycolysis in NPC cells, and ATRA upregulated LPLUNC1 expression, ATRA maybe a promising drug for the treatment of NPC.

Development and validation a radiomics nomogram for predicting thymidylate synthase status in hepatocellular carcinoma based on Gd-DTPA contrast enhanced MRI.

OBJECTIVES: The purpose of this study was to develop and validate a radiomics nomogram for predicting thymidylate synthase (TYMS) status in hepatocellular carcinoma (HCC) by using Gd-DTPA contrast enhanced MRI. METHODS: We retrospectively enrolled 147 consecutive patients with surgically confirmed HCC and randomly allocated to training and validation set (7:3). The TYMS status was immunohistochemical determined and classified into low TYMS (positive cells ≤ 25%) and high TYMS (positive cells > 25%) groups. Radiomics features were extracted from the arterial phases and portal venous phase of Gd-DTPA contrast enhanced MRI. Least absolute shrinkage and selection operator (LASSO) were applied for generating the Rad score. Clinical data and MRI findings were assessed to build a clinical model. Rad score combined with clinical features was used to construct radiomics nomogram. RESULTS: A total of 2260 features were extracted and reduced to 7 features as the most important discriminators to build the Rad score. InAFP was identified as the only independent clinical factors for TYMS status. The radiomics nomogram showed good discrimination in training (AUC, 0.759; 95% CI 0.665-0.838) and validation set (AUC, 0.739; 95% CI 0.585-0.860), and showed better discrimination capability (P < 0.05) compared with clinical model in training (AUC, 0.656; 95% CI 0.555-0.746) and validation set (AUC, 0.622; 95% CI 0.463-0.764). CONCLUSIONS: The radiomics nomogram shows favorable predictive efficacy for TYMS status in HCC, which might be helpful for the personalized treatment of HCC.

Diverse Reactions of o-Carborane-Fused Silylenes with C≡E (E = C, P) Triple Bonds.

The reactivities of o-carborane-fused silylenes toward molecules with C≡E (E = C, P) bonds are reported. The reactions of bis(silylene) [(LSi:)C]2B10H10 (1a, L = PhC(NtBu)2) with arylalkynes afforded bis(silylium) carborane adducts 2 and 3, showing a Si(µ-C2)Si structure with an open-cage nido-carborane backbone. In contrast, the reaction of 1a with a phosphaalkyne AdC≡P (Ad = 1-adamantyl) smoothly furnished compound 4, comprising fused CPSi rings with a C=Si double bond and Si-Si single bond, and the related formation mechanism was investigated by DFT calculations. Furthermore, when monosilylene [(LSi:)C]CHB10H10 (1b) was employed to react with AdC≡P, compound 5 was isolated. The structure of 5 features a 1,2,3-triphosphetene core. All products were characterized by NMR spectroscopy and/or X-ray crystallography.

Impacts and mechanisms of alternative mRNA splicing in cancer metabolism, immune response, and therapeutics.

Alternative pre-mRNA splicing (AS) provides the potential to produce diversity at RNA and protein levels. Disruptions in the regulation of pre-mRNA splicing can lead to diseases. With the development of transcriptome and genome sequencing technology, increasing diseases have been identified to be associated with abnormal splicing of mRNAs. In tumors, abnormal alternative splicing frequently plays critical roles in cancer pathogenesis and may be considered as new biomarkers and therapeutic targets for cancer intervention. Metabolic abnormalities and immune disorders are important hallmarks of cancer. AS produces multiple different isoforms and diversifies protein expression, which is utilized by the immune and metabolic reprogramming systems to expand gene functions. The abnormal splicing events contributed to tumor progression, partially due to effects on immune response and metabolic reprogramming. Herein, we reviewed the vital role of alternative splicing in regulating cancer metabolism and immune response. We discussed how alternative splicing regulates metabolic reprogramming of cancer cells and antitumor immune response, and the possible strategies to targeting alternative splicing pathways or splicing-regulated metabolic pathway in the context of anticancer immunotherapy. Further, we highlighted the challenges and discuss the perspectives for RNA-based strategies for the treatment of cancer with abnormally alternative splicing isoforms.

Association between oral infections, triglyceride-glucose index, and in-stent restenosis.

OBJECTIVES: To investigate oral infections in patients suffering in-stent restenosis (ISR) and non-ISR and analyze the possible correlation between the oral infection and triglyceride-glucose (TyG) index, a clinical surrogate indicator of insulin resistance (IR). MATERIALS AND METHODS: A cross-sectional design was used, in which 586 patients with acute coronary syndrome who underwent coronary angiography 6-24 months after coronary stent implantation were recruited. The modified total dental index (TDI) was used to evaluate the status of oral inflammation. RESULTS: In both univariate analyses, TDI scores [3 (1.5, 4.5) vs. 2.5 (1.5, 4.0), p < 0.01] and a multivariate regression model (OR = 1.202, 95% CI = 1.085-1.333, p < 0.01), the TDI significantly correlated with ISR. The TyG index was positively associated with ISR (OR = 1.766, 95% CI = 1.055-2.957, p < 0.05). Correlation analysis showed that TDI was positively correlated with TyG index (r = 0.190, p < 0.01). Using linear regression analysis, higher TDI scores were significantly associated with IR (95% CI = 0.029-0.063, p < 0.01). CONCLUSIONS: Oral infections and TyG index were independently and positively correlated with ISR in patients with acute coronary syndrome. Oral inflammatory burden assessed by TDI score was associated with IR.

Machine learning algorithms for integrating clinical features to predict intracranial hemorrhage in patients with acute leukemia.

BACKGROUND: Intracranial hemorrhage (ICH) in acute leukemia (AL) patients leads to high morbidity and mortality, treatment approaches for ICH are generally ineffective. Thus, early identification of which subjects are at high risk of ICH is of key importance. Currently, machine learning can achieve well predictive capability through constructing algorithms that simultaneously exploit the information coming from clinical features. METHODS: After rigid data preprocessing, 42 different clinical features from 948 AL patients were used to train different machine learning algorithms. We used the feature selection algorithms to select the top 10 features from 42 clinical features. To test the performance of the machine learning algorithms, we calculated area under the curve (AUC) values from receiver operating characteristic (ROC) curves along with 95% confidence intervals (CIs) by cross-validation. RESULTS: With the 42 features, RF exhibited the best predictive power. After feature selection, the top 10 features were international normalized ratio (INR), prothrombin time (PT), creatinine (Cr), indirect bilirubin (IBIL), albumin (ALB), monocyte (MONO), platelet (PLT), lactic dehydrogenase (LDH), fibrinogen (FIB) and prealbumin (PA). Among the top 10 features, INR, PT, Cr, IBIL and ALB had high predictive performance with an AUC higher than 0.8 respectively. CONCLUSIONS: The RF algorithm exhibited a higher cross-validated performance compared with the classical algorithms, and the selected important risk features should help in individualizing aggressive treatment in AL patients to prevent ICH. Efforts that will be made to test and optimize in independent samples will warrant the application of such algorithm and predictors in the future.

Genome-wide identification of auxin response factor (ARF) gene family and the miR160-ARF18-mediated response to salt stress in peanut (Arachis hypogaea L.).

Auxin response factors (ARFs) are transcription factors that regulate the transcription of auxin-responsive genes during plant growth and development. In this study, 29 and 30 ARF members were identified from the two wild peanut species, A. duranensis and A. ipaensis, respectively. The ARFs, including their classifications, conserved domains and evolutionary relationships were characterized. RNA-seq analyses revealed that some of the ARF genes were responsive to abiotic stress, particularly high salinity. In addition to abiotic stress, the expression of 2 ARF members was also regulated by biotic stress, specifically Bradyrhizobium infection in A. duranensis. The ARF gene Arahy.7DXUOK was predicted to be a potential target of miR160. Overexpression of miR160 could cause degradation of the Arahy.7DXUOK target gene transcript and increased salt tolerance in miR160OX transgenic plants. Therefore, these molecular characterization and expression profile analyses provide comprehensive information on ARF family members and will help to elucidate their functions to facilitate further research on peanuts.

Regulation of cancer progression by circRNA and functional proteins.

Circular RNAs (circRNAs) are closed back-splicing products of precursor mRNA in eukaryotes. Compared with linear mRNAs, circRNAs have a special structure and stable expression. A large number of studies have provided different regulatory mechanisms of circRNAs in tumors. Challenges exist in understanding the control of circRNAs because of their sequence overlap with linear mRNA. Here, we survey the most recent progress regarding the regulation of circRNA biogenesis by RNA-binding proteins, one of the vital functional proteins. Furthermore, substantial circRNAs exert compelling biological roles by acting as protein sponges, by being translated themselves or regulating posttranslational modifications of proteins. This review will help further explore more types of functional proteins that interact with circRNA in cancer and reveal other unknown mechanisms of circRNA regulation.

Identification and characterization of transposable element AhMITE1 in the genomes of cultivated and two wild peanuts.

BACKGROUND: The cultivated peanut (Arachis hypogaea L., AABB) is an allotetraploid hybrid between two diploid peanuts, A. duranensis (AA genome) and A. ipaensis (BB genome). Miniature inverted-repeat transposable elements (MITEs), some of which are known as active nonautonomous DNA transposons with high copy numbers, play important roles in genome evolution and diversification. AhMITE1, a member of the MITE family of transposons, but information on the peanut genomes is still limited. Here, we analyzed AhMITE1, AuMITE1 and ApMITE1 in the cultivated (A. hypogaea) and two wild peanut (A. duranensis and A. ipaensis) genomes. RESULTS: The cultivated and the two wild peanut genomes harbored 142, 14 and 21 AhMITE1, AuMITE1 and ApMITE1 family members, respectively. These three family members exhibited highly conserved TIR sequences, and insertions preferentially occurred within 2 kb upstream and downstream of gene-coding and AT-rich regions. Phylogenetic and pairwise nucleotide diversity analysis showed that AhMITE1 and ApMITE1 family members have undergone one round of amplification bursts during the evolution of the peanut genome. PCR analyses were performed in 23 peanut varieties and demonstrated that AhMITE1 is an active transposon and that hybridization or chemical mutagenesis can promote the mobilization of AhMITE1. CONCLUSIONS: AhMITE1, AuMITE1 and ApMITE1 family members were identified based on local BLAST search with MAK between the cultivated and the two wild peanut genomes. The phylogenetic, nucleotide diversity and variation copy numbers of AhMITE1, AuMITE1 and ApMITE1 members provides opportunities for investigating their roles during peanut evolution. These findings will contribute to knowledge on diversity of AhMITE1, provide information about the potential impact on the gene expression and promote the development of DNA markers in peanut.

Long non-coding RNAs are involved in alternative splicing and promote cancer progression.

Alternative splicing (AS) is a key process in which precursor RNAs produce different mature RNAs, and the disorder of AS is a key factor in promoting cancer development. Compared with coding RNA, studies on the functions of long non-coding RNAs (lncRNAs) are far from enough. In fact, lncRNA is an important participant and regulator in the process of AS. On the one hand, lncRNAs regulate cancer progression as AS products of precursor messenger RNA (mRNA), but on the other hand, precursor lncRNA generates cancer-related abnormal splicing variants through AS. In addition, lncRNAs directly or indirectly regulate the AS events of downstream target genes, thus affecting the occurrence and development of cancer. Here, we reviewed how lncRNAs regulate AS and influence oncogenesis in different ways.

An efficient and cost-effective method for the purification of human basophils.

Human basophils are terminally differentiated granulocytes that are least abundant in the peripheral blood but play important roles in allergic diseases. Studies on human basophils are limited by the high cost on the isolation of human basophils by magnetic-activated cell sorting (MACS) for negative depletion of non-basophils, followed by CD123-based positive selection of basophils. Moreover, such CD123-based purification of basophils may be limited by blocking of the binding of IL-3/anti-CD123 to the surface CD123. Here we identified SSClow CD4- CD127- HLA-DR- CRTH2high as unique markers for the identification of human basophils through stringent flow cytometric analysis of leukocytes from buffy coat. We established an efficient and cost-effective method for isolating human basophils from buffy coat based on positive magnetic selection of CRTH2+ cells followed by flow cytometric sorting of SSClow CD4- CD127- HLA-DR- CRTH2high cells. Approximately 1 to 1.5 million basophils were isolated from one buffy coat with a purity of >97%. Basophils purified by this method were viable and efficiently responded to key regulators of basophils including IL-3 and anti-IgE. This method can be used for purifying human basophils for subsequent functional studies.

The APETALA2-Like Transcription Factor SUPERNUMERARY BRACT Controls Rice Seed Shattering and Seed Size.

The elimination of seed shattering was a crucial event during crop domestication. Improving and fine-tuning the regulation of this process will further enhance grain yield by avoiding seed losses during crop production. In this work, we identified the loss-of-shattering mutant suppression of shattering1 (ssh1) through a screen of mutagenized wild rice (Oryza rufipogon) introgression lines with naturally high shattering. Using the MutMap approach and transformation experiments, we isolated a genetic factor for seed shattering, SSH1, which is an allele of SUPERNUMERARY BRACT (SNB), a gene encoding a plant-specific APETALA2-like transcription factor. A C-to-A point mutation in the ninth intron of SNB altered the splicing of its messenger RNA, causing the reduced shattering of the ssh1 mutant by altering the development of the abscission layer and vascular bundle at the junction between the seed and the pedicel. Our data suggest that SNB positively regulates the expression of two rice REPLUMLESS orthologs, qSH1 and SH5 In addition, the ssh1 mutant had larger seeds and a higher grain weight, resulting from its increased elongation of the glume longitudinal cells. The further identification of favorable SNB alleles will be valuable for improving rice seed shattering and grain yield using molecular breeding strategies.

Genetic and transcriptomic dissection of an artificially induced paired spikelets mutant of wheat (Triticum aestivum L.).

KEY MESSAGE: Morphological, genetic and transcriptomic characterizations of an EMS-induced wheat paired spikelets (PS) mutant were performed. A novel qualitative locus WPS1 on chromosome 1D was identified. Grain yield of wheat is significantly associated with inflorescence or spike architecture. However, few genes related to wheat spike development have been identified and their underlying mechanisms are largely unknown. In this study, we characterized an ethyl methanesulfonate (EMS)-induced wheat mutant, wheat paired spikelets 1 (wps1). Unlike a single spikelet that usually develops at each node of rachis, a secondary spikelet appeared below the primary spikelet at most of the rachis nodes of wps1. The microscope observation showed that the secondary spikelet initiated later than the primary spikelet. Genetic analysis suggested that the PS of wps1 is controlled by a single dominant nuclear gene, designated WHEAT PAIRED SPIKELETS 1 (WPS1). Further RNA-seq based bulked segregant analysis and molecular marker mapping localized WPS1 in an interval of 208.18-220.92 Mb on the chromosome arm 1DL, which is different to known genes related to spike development in wheat. By using wheat omics data, TraesCS1D02G155200 encoding a HD-ZIP III transcription factor was considered as a strong candidate gene for WPS1. Transcriptomic analysis indicated that PS formation in wps1 is associated with auxin-related pathways and may be regulated by networks involving TB1, Ppd1, FT1, VRN1, etc. This study laid the solid foundation for further validation of the causal gene of WPS1 and explored its regulatory mechanism in PS formation and inflorescence development, which may benefit to kernel yield improvement of wheat based on optimization or design of spike architecture in the future.

Genetic dissection of quantitative trait loci for grain size and weight by high-resolution genetic mapping in bread wheat (Triticum aestivum L.).

KEY MESSAGE: Six major QTLs for wheat grain size and weight were identified on chromosomes 4A, 4B, 5A and 6A across multiple environments, and were validated in different genetic backgrounds. Grain size and weight are crucial components of wheat yield. Dissection of their genetic control is thus essential for the improvement of yield potential in wheat breeding. We used a doubled haploid (DH) population to detect quantitative trait loci (QTLs) for grain width (GW), grain length (GL), and thousand grain weight (TGW) in five environments. Six major QTLs, QGw.cib-4B.2, QGl.cib-4A, QGl.cib-5A.1, QGl.cib-6A, QTgw.cib-4B, and QTgw.cib-5A, were consistently identified in at least three individual environments and in best linear unbiased prediction (BLUP) datasets, and explained 5.65-34.06% of phenotypic variation. QGw.cib-4B.2, QTgw.cib-4B, QGl.cib-5A.1 and QGl.cib-6A had no effect on grain number per spike (GNS). In addition to QGl.cib-4A, the other major QTLs were further validated by using Kompetitive Allele Specific PCR (KASP) markers in different genetic backgrounds. Moreover, significant interactions between the three major GL QTLs and two major TGW QTLs were observed. Comparison analysis showed that QGl.cib-5A.1 and QGl.cib-6A are likely new loci. Notably, QGw.cib-4B.2 and QTgw.cib-4B were co-located on chromosome 4B and improved TGW by increasing only GW, unlike nearby or overlapped loci reported previously. Three genes associated with grain development within the QGw.cib-4B.2/QTgw.cib-4B interval were identified by searches on sequence similarity, spatial expression patterns, and orthologs. The major QTLs and KASP markers reported here will be useful for elucidating the genetic architecture of grain size and weight and for developing new wheat cultivars with high and stable yield.

Isolation of Silacycles from the Reactions of a Monochlorosilylene LSi(:)Cl (L = PhC(NtBu)2) with Ethynyl Lithium Salts.

The reactions of amidinate silylene chloride LSi(:)Cl (L = PhC(NtBu)2) with TMS- and Ph-ethynyl lithium salts gave rise to silacycles 1 and 4, respectively. The formation of 1 and 4 may undergo cyclo-condensations of transient ethynylsilylene intermidiates and the activation of an amidinate backbone. The distinct structures of 1 and 4 may be derived from the different electronic or steric properties of ethynyl substituents, and their formation mechanisms were investigated by density functional theory (DFT) calculations. Moreover, a sequential reaction of LSi(:)Cl with BH3·SMe2 and TMSC≡CLi as well as a reaction of LSi(:)Cl with TMSC≡CLi under O2 exclusively obtained ethynylsilanes 2 and 3, respectively, which indicated that either blocking a lone pair of a Si(II) atom or oxidizing Si(II) to Si(IV) prevents the further conversion of ethynylsilylenes to silacycle 1. All products were characterized by NMR spectroscopy and X-ray crystallography.

Breeding of a new variety of peanut with high-oleic-acid content and high-yield by marker-assisted backcrossing.

Peanut (Arachis hypogaea L.) is an important crop used for oil production, and oleic acid is a major factor in determining oil quality. Alterations in the oleic acid content can improve the nutritional quality and oxidative stability and prolong the shelf life of peanut products. The objective of this study was to develop a peanut variety with a high-oleic-acid content and high yield. One elite variety, "huayu22," was hybridized with the high-oleic-acid "KN176" donor and backcrossed for four generations as the recurrent parent using fad2 marker-assisted backcross selection. Based on the Kompetitive allele-specific PCR (KASP) screening of fad2 markers, the oleic acid content of advanced generations derived by selfing was assessed by near-infrared reflectance spectroscopy and gas chromatography. The genetic background recovery rate of four BC4F4 lines showed an average of 92.34% and was confirmed by genotyping using the Axiom_Arachis 58 K SNP array. Across these superior lines in BC4F6 generations, one line with a high-oleic-acid content and high yield was detected and named "YH61." In particular, yield comparison experiments showed that YH61 exhibited high and stable yield at three different locations and was moderately resistant to leaf spot disease. The distinctness, uniformity and stability (DUS) testing for two consecutive years suggested that YH61 reached the standard for variety rights application. The use of the peanut variety YH61 contributed to the expansion of the cultivation area due to its high value in the oleic acid market and the proven economic benefits in China. This study demonstrated that the marker-assisted backcross strategy based on a cost-effective KASP assay and SNP array for the detection of mutations in fad2 and genetic background evaluation can be used to create efficient peanut breeding programs and contribute to oil quality and high-yield stability. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-022-01313-9.