Fatty acid de novo biosynthesis in plastids: Key enzymes and their critical roles for male reproduction and other processes in plants.

Fatty acid de novo biosynthesis in plant plastids is initiated from acetyl-CoA and catalyzed by a series of enzymes, which is required for the vegetative growth, reproductive growth, seed development, stress response, chloroplast development and other biological processes. In this review, we systematically summarized the fatty acid de novo biosynthesis-related genes/enzymes and their critical roles in various plant developmental processes. Based on bioinformatic analysis, we identified fatty acid synthase encoding genes and predicted their potential functions in maize growth and development, especially in anther and pollen development. Finally, we highlighted the potential applications of these fatty acid synthases in male-sterility hybrid breeding, seed oil content improvement, herbicide and abiotic stress resistance, which provides new insights into future molecular crop breeding.

K2Cr2O7-induced DNA damage in HT1080 cells: Electrochemical signal response mechanism.

The existing DNA damage detection technology cannot meet the current detection requirements. It is critical to build new methods and discover novel biomarkers. In this study, alkaline comet and 8-OHDG ELISA assays were used to identify DNA damage in HT-1080 cells exposed to K2Cr2O7, and electrochemical behaviors of HT-1080 cells with DNA damage was studied. With an increase in K2Cr2O7 exposure time, two electrochemical signals from HT-1080 cells at 0.69 and 1.01 V steadily grew before decreasing after reaching their highest values. The electrochemical signal's initial response time and peak time decreased as the concentration of K2Cr2O7 increased. The duration of the high dose group was 0.5 and 1 h, while the low dose group was 1.5 and 6 h. Western blotting analysis revealed that DNA damage increased the expression of proteins involved in catabolism and de novo purine synthesis, particularly de novo purine synthesis. Expressions of PRPP amidotransferase, IMPDH, and ADA were all higher than those of ADSS, XOD, and GDA, which resulted in larger concentrations of hypoxanthine, guanine, and xanthine, and in turn improved electrochemical signaling. These findings suggest that intracellular purine identified by linear scan voltammetry is predicted to evolve as a marker of early DNA damage.

Efficient macrocyclization facilitated by skeleton preorganization.

Reported here is the efficient macrocyclization facilitated by skeleton preorganization. A pyridylcarbazole macrocycle and a phenylpyridylcarbazole macrocycle was synthesized in yield up to 75%. Single-crystal structures and theoretic computation uncovered that the skeleton preorganization promoted the formation of cyclization-favorable conformation of noncyclic precursors via π⋯π interactions. This result provided a new approach for the efficient syntheses of macrocycles.

Expression pattern, tumor immune landscape, and prognostic value of N7­methylguanosine regulators in bladder urothelial carcinoma.

N7-Methylguanosine (m7G) modification is important in post-transcriptional regulation. dysregulation of m7G RNA modification has been reported to be markedly associated with cancer. However, its importance in bladder urothelial carcinoma (BLCA) remains poorly characterized. The present study systematically analyzed mRNA gene expression data and clinical information from The Cancer Genome Atlas and further constructed robust risk signatures for the four regulators of m7G RNA modification (nudix hydrolase 11, gem nuclear organelle-associated protein 5, eukaryotic translation initiation factor 3 subunit D and cytoplasmic FMR1 interacting protein 1). The differential expression and cell function of m7G-related genes in bladder cancer cells were verified by reverse transcription-quantitative PCR, Cell Counting Kit-8 and colony formation assays. The four-gene-based model could accurately predict the prognosis of BLCA. Nomogram-based clinical decisions had a higher net benefit compared with that of individual predictors. Through immune infiltration analysis, it was found that immune cell infiltration affected the prognosis of patients with BLCA. Finally, the present study identified potential therapeutics that differ between high and low-risk groups based on four genes. In summary, the current findings revealed an essential role for m7G RNA modification regulators in BLCA, and developed risk signatures as promising prognostic markers in patients with BLCA.

Alkynyl Acylazolium: A Versatile 1,3-Bielectrophilic 3C-Synthon in NHC-Organocatalysis.

N-Heterocyclic carbene (NHC) organocatalysis has emerged as a powerful tool in the field of modern organic synthesis especially in the asymmetric construction of various cyclic skeletons. As an emerging NHC-bound 1,3-bielectrophilic intermediate, alkynyl acylazolium has drawn substantial attention in recent years, and has been used as a versatile 3C-synthon in synthesizing valuable organic molecules since its discovery. In this review, focused on the different pathways for the formation of alkynyl acylazoliums from different precursors like alkynoic esters, alkynoic acids and ynals, the recent advances in the transformations and applications of alkynyl acylazoliums pioneered or developed over the last decade under NHC-catalysis were summarized comprehensively. At the same time, the outlook for further investigation and exploration of novel reaction modes for alkynyl acylazoliums in the future was also discussed.

Predictors and long-term outcomes of heart block after transcatheter device closure of perimembranous ventricular septal defect.

Background: Heart block is the most common and concerning complication associated with transcatheter device closure of perimembranous ventricular septal defect (pmVSD) and its occurrence remains a great challenge for device closure. Methods: Between June 2002 and June 2020, 1076 pediatric patients with pmVSD, who successfully underwent transcatheter device closure in our center, were enrolled in this cohort study, with a median follow-up of 64 months (range: 1 to 19 years). Results: Of 1076 patients, 234 (21.8%) developed postprocedural heart block, with right bundle branch block being the most common (74.8%), followed by left bundle branch block (16.2%), and atrioventricular block (5.6%). Complete atrioventricular block occurred in 5 cases, including 3 cases with permanent pacemaker implantation, 1 case with recovery to normal sinus rhythm, and 1 case with sudden cardiac death. Most patients (97.9%) developed heart block within 1 week of procedure. Finally, 138 cases returned to normal cardiac conduction. Multivariate logistic regression revealed that thin-waist occluders (odds ratio [OR]: 1.759; 95% confidence interval [CI]: 1.023 to 3.022; P = 0.041), and oversized devices (OR: 1.809; 95% CI: 1.322 to 2.476; P < 0.001) were independently associated with occurrence of postprocedural heart block. Moreover, heart block was less likely to occur when the left disk of occluder was placed within the aneurysmal tissue (OR: 0.568; 95% CI: 0.348 to 0.928; P = 0.024). Conclusion: The outcome of postprocedural heart block is favorable in most cases. Oversized devices and thin-waist occluders should be avoided. Placement of the left disk of the device should into the aneurysmal tissue is highly recommended.

Atroposelective Synthesis of Triaryl α-Pyranones with 1,2-Diaxes by N-Heterocyclic Carbene Organocatalysis.

Atropisomers bearing multiple stereogenic axes are of increasing importance to the field of material science, pharmaceuticals, and catalysis. However, the atroposelective construction of multi-axis atropisomers remains rare and challenging, due to the intrinsical difficulties in the stereo-control of the multiple stereogenic axes. Herein, we demonstrate a single-step construction of a new class of 1,2-diaxially chiral triaryl α-pyranones by an N-heterocyclic carbene organocatalytic asymmetric [3+3] annulation of well-designed alkynyl acylazolium precursors and enolizable sterically hindered 2-aryl ketones. The protocol features broad substrate scope (>50 examples), excellent stereo-control (most cases >20 : 1 dr, up to 99.5 : 0.5 er), and potentially useful synthetic applications. The success of this reaction relies on the rational design of structurally matched reaction partners and the careful selection of the asymmetric catalytic system. DFT calculations have also been performed to discover and rationalize the origin of the high stereoselectivity of this reaction.

Correlation analysis of intestinal flora and immune function in patients with primary hepatocellular carcinoma.

Background: This study applied metagenomic sequencing technology to analyze the intestinal flora distribution and immune function of patients with primary liver cancer. Methods: Stool samples were collected from 10 patients with primary liver cancer (primary liver cancer group) and 10 healthy subjects (healthy control group) who were admitted to The Affiliated Changzhou No. 2 People's Hospital of Nanjing Medical University from March to June 2021. The general data of the patients were recorded. Metagenomic sequencing was performed, and principal component analysis and diversity analysis were used to analyze the structure of the two groups and compare the differences in species abundance. United States Employment Service (USES) Spearman correlation analysis was applied to examine vice Streptococcus blood, saliva, Streptococcus, Streptococcus mutans, Streptococcus thermophilus, and vice Haemophilus influenzae, WeiRong aureus, existing different WeiRong bacteria, Eosinophilic mucins Ekman bacteria, responding to bacteria, the other branch bacteria abundance and in alanine aminotransferase (ALT), aspartate aminotransferase (AST), valley correlation between levels of amyltranspeptidase (GGT), total protein, total bilirubin and alpha-fetoprotein (AFP). Results: Beta diversity analysis based on Bray and Jensen-Shannon Divergence (JSD) distance measurement showed that the heterogeneity of fecal flora in the hepatic cell carcinoma (HCC) group was significantly lower than that in the healthy control group (P<0.001. At the species level of bacterial taxonomy, there was a statistically significant difference in the distribution of 137 bacteria in the healthy control and primary liver cancer groups (P<0.05). Correlation analysis showed that Streptococcus salivarius (P=0.020), Streptococcus thermophilus (P=0.002), and Haemophilus parainfluenzae (P=0.023) were significantly positively correlated with the serum ALT level. There were also notable correlations with AST (P=0.049), GGT (P=0.037), and total protein (P=0.010). Conclusions: The diversity of intestinal flora in patients with primary liver cancer is significantly reduced, species abundance is altered, and there is a marked imbalance of intestinal flora. Therefore, specific bacterial species with different intestinal flora may be used as biomarkers for the early diagnosis of primary liver cancer.

Enantioselective Synthesis of δ-Carbolinones via N-Heterocyclic Carbene Catalysis.

An enantioselective synthesis of δ-carbolinones was accomplished through N-heterocyclic carbene-catalyzed formal [3+3] annulation of 3-aminoindoles with 2-bromoenals. This protocol offers a rapid and efficient synthetic approach for accessing a wide range of enantioenriched structurally interesting δ-carbolinones under mild reaction conditions.

N-Heterocyclic Carbene-Catalyzed Enantioselective Synthesis of Carbocycle-Fused Uracils via Formal [4 + 2] Annulation/Lactone Formation/Decarboxylation Cascade.

An unprecedented organocatalytic asymmetric construction of novel six-membered carbocycle fused uracils has been demonstrated by the reaction of the remotely enolizable 6-methyluracil-5-carbaldehydes with 2-bromoenals. The reaction involves an N-heterocyclic carbene-catalyzed formal [4 + 2] annulation of o-quinodimethane (oQDM) dienolates with α,ß-unsaturated acylazoliums, followed by a cascade lactone formation/decarboxylation process. This protocol unlocks a new platform to access enantioenriched carbocycle-fused uracils.

Impacts and mechanisms of metabolic reprogramming of tumor microenvironment for immunotherapy in gastric cancer.

Metabolic disorders and abnormal immune function changes occur in tumor tissues and cells to varying degrees. There is increasing evidence that reprogrammed energy metabolism contributes to the development of tumor suppressive immune microenvironment and influences the course of gastric cancer (GC). Current studies have found that tumor microenvironment (TME) also has important clinicopathological significance in predicting prognosis and therapeutic efficacy. Novel approaches targeting TME therapy, such as immune checkpoint blockade (ICB), metabolic inhibitors and key enzymes of immune metabolism, have been involved in the treatment of GC. However, the interaction between GC cells metabolism and immune metabolism and how to make better use of these immunotherapy methods in the complex TME in GC are still being explored. Here, we discuss how metabolic reprogramming of GC cells and immune cells involved in GC immune responses modulate anti-tumor immune responses, as well as the effects of gastrointestinal flora in TME and GC. It is also proposed how to enhance anti-tumor immune response by understanding the targeted metabolism of these metabolic reprogramming to provide direction for the treatment and prognosis of GC.

N-Heterocyclic Carbene-Catalyzed Formal [3+3] Annulation of Alkynyl Acylazoliums for the Synthesis of Benzofuro[3,2-b]pyridin-2-ones.

Through ß-activation of alkynoic acid esters with N-heterocyclic carbene catalysis, a formal [3+3] annulation of alkynyl acylazoliums with indolin-3-ones has been developed for the rapid construction of structurally interesting benzofuro[3,2-b]pyridin-2-ones with potential bioactivities. This protocol provides a highly efficient and simple method for the synthesis of the target molecules under mild reaction conditions with a wide substrate scope and excellent chemoselectivity. The synthetic utility of this protocol was also demonstrated by the versatile late-stage modifications.

Extracellular vesicles in neurodegenerative diseases: Insights and new perspectives.

Extracellular vesicles (EVs) are vesicle-like substances released by eukaryotic cells. Based on their origin and size, EVs are mainly divided into exosomes, microvesicles and apoptotic bodies, and they are secreted by eukaryotic cells under physiological and pathological conditions. EVs are enriched with nucleic acids, proteins and other factors. EVs can regulate the function of adjacent and distant cells, and they are even involved in the pathogenesis of diseases. They contain proteins associated with the pathogenesis of neurodegenerative diseases (NDs), such as the α-synuclein (α-syn) and tau proteins, which suggest potential roles for EVs as biomarkers and carriers of drugs and other therapeutic molecules that can cross the blood-brain barrier to treat NDs. In this review, we summarized the function of EVs in the pathogenesis of different NDs and related advances in EVs as diagnostic biomarkers and treatments for diseases.

Down-regulated long non-coding RNA RMST ameliorates dopaminergic neuron damage in Parkinson's disease rats via regulation of TLR/NF-κB signaling pathway.

OBJECTIVE: Current treatment and prognosis of Parkinson's disease (PD) are not ideal. This study explored the mechanism of long non-coding RNA (lncRNA) rhabdomyosarcoma 2-associated transcript (RMST) in dopaminergic (DA) neuron damage in PD rats. METHODS: PD rats were modeled and injected with RMST silence or overexpression vectors to figure out its roles in oxidative stress, the apoptosis of DA neurons in brain substantia nigra (SN), and neurobehavioral activities of PD rats. Tyrosine hydroxylase (TH), synaptophysin (SYN), glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule (Iba-1) in SN were detected. RMST and Toll-like receptor (TLR)/nuclear factor kappa B (NF-κB) pathway-related factors were detected. RESULTS: RMST expression in brain SN of rats, TLR2, TLR4 expression in neurons and NF-κB expression in cell nucleus were increased. Silenced RMST improved the neurobehavioral activities, depressed oxidative stress and neuronal apoptosis, increased TH and SYN expression, and reduced the activation degree of glial cells in SN and the inflammatory response via reducing GFAP and Iba-1. Moreover, reduced RMST reduced TLR2 and TLR4 expression in neurons and NF-κB expression in cell nucleus in PD rats. CONCLUSION: Inhibited RMST attenuates DA neuron damage in PD rats, which may be implicated with TLR/NF-κB signaling pathway.

ZmMs25 encoding a plastid-localized fatty acyl reductase is critical for anther and pollen development in maize.

Fatty acyl reductases (FARs) catalyse the reduction of fatty acyl-coenzyme A (CoA) or -acyl carrier protein (ACP) substrates to primary fatty alcohols, which play essential roles in lipid metabolism in plants. However, the mechanism by which FARs are involved in male reproduction is poorly defined. Here, we found that two maize allelic mutants, ms25-6065 and ms25-6057, displayed defective anther cuticles, abnormal Ubisch body formation, impaired pollen exine formation and complete male sterility. Based on map-based cloning and CRISPR/Cas9 mutagenesis, Zm00001d048337 was identified as ZmMs25, encoding a plastid-localized FAR with catalytic activities to multiple acyl-CoA substrates in vitro. Four conserved residues (G101, G104, Y327 and K331) of ZmMs25 were critical for its activity. ZmMs25 was predominantly expressed in anther, and was directly regulated by transcription factor ZmMYB84. Lipidomics analysis revealed that ms25 mutation had significant effects on reducing cutin monomers and internal lipids, and altering the composition of cuticular wax in anthers. Moreover, loss of function of ZmMs25 significantly affected the expression of its four paralogous genes and five cloned lipid metabolic male-sterility genes in maize. These data suggest that ZmMs25 is required for anther development and male fertility, indicating its application potential in maize and other crops.

Curcumin slows the progression of Alzheimer's disease by modulating mitochondrial stress responses via JMJD3-H3K27me3-BDNF axis.

Disturbance of mitochondrial proteins by amyloid beta-protein (Aß) that associates with mitochondrial stress responses (MSR) is one of the pathological mechanisms of Alzheimer's disease (AD). This study tried to explore whether the axis of Jumonji domain-containing protein 3 (JMJD3)-trimethylated lysine 27 on histone H3 (H3K27me3)-brain derived neurotrophic factor (BDNF) is involved in the regulation of MSR which in turn intervenes in the process of AD, and whether curcumin (CUR) has a protective role against AD by influencing this axis, aiming to provide insights into AD treatment. AD mouse models presented a significant aggregation of Aß, with conspicuous pathological changes in brain tissues and an increase in neuronal apoptosis. Moreover, the mRNA and protein levels of JMJD3 and BDNF were down-regulated, H3K27me3 methylation levels were increased, and the MSR markers (ClpP, HSP6, HSP-60, and ATFS-1) showed abnormal alterations. In in-vitro cellular models of AD, up-regulation of either JMJD3 or BDNF up-regulated BDNF levels, down-regulated H3K27me3 methylation levels, mitigated abnormalities of MSR markers and Aß aggregation, and increased cell proliferation and inhibited apoptosis. JMJD3 was confirmed to regulate Aß and MSR via BDNF. In addition, CUR was confirmed to modulate JMJD3-H3K27me3-BDNF axis. Furthermore, moderate and high doses of CUR could improve the morphology and histopathology of the brain, inhibit Aß aggregation and cell apoptosis, and maintain MSR balance at least partly by modulating the JMJD3-H3K27me3-BDNF axis. To sum up, moderate and high doses of CUR regulate the progression of AD via MSR JMJD3-H3K27me3-BDNF axis.

The values of AHCY and CBS promoter methylation on the diagnosis of cerebral infarction in Chinese Han population.

BACKGROUND: The goal of our study is to investigate whether the methylation levels of AHCY and CBS promoters are related to the risk of cerebral infarction by detecting the methylation level of AHCY and CBS genes. METHODS: We extracted peripheral venous blood from 152 patients with cerebral infarction and 152 gender- and age-matched healthy controls, and determined methylation levels of AHCY and CBS promoters using quantitative methylation-specific polymerase chain reaction. We used the percentage of methylation reference (PMR) to indicate gene methylation level. RESULTS: We compared the promoter methylation levels of two genes (AHCY and CBS) in peripheral blood DNA between the cerebral infarction case group and the control group. Our study showed no significant difference in AHCY promoter methylation between case and control. Subgroup analysis by gender showed that the methylation level of AHCY in males in the case group was lower than that in the control group, but the difference was not statistically significant in females. In a subgroup analysis by age, there was no significant difference in the AHCY methylation level between the case and control in the young group (≤44 years old). However, the level of AHCY gene methylation in the middle-aged group (45-59 years old) was significantly higher and the aged group (≥60 years old) was significantly lower than that in the control groups. However, CBS promoter methylation levels were significantly lower in the case group than in the control group (median PMR: 70.20% vs 104.10%, P = 3.71E-10). In addition, the CBS methylation levels of males and females in the case group were significantly lower than those in the control group (male: 64.33% vs 105%, P = 2.667E-08; female: 78.05% vs 102.8%, P = 0.003). We also found that the CBS levels in the young (23-44), middle-aged (45-59), and older (60-90) groups were significantly lower than those in the control group (young group: 69.97% vs 114.71%; P = 0.015; middle-aged group: 56.04% vs 91.71%; P = 6.744E-06; older group: 81.6% vs 119.35%; P = 2.644E-04). Our ROC curve analysis of CBS hypomethylation showed an area under the curve of 0.713, a sensitivity of 67.4%, and a specificity of 74.0%. CONCLUSION: Our study suggests that hypomethylation of the CBS promoter may be closely related to the risk of cerebral infarction and may be used as a non-invasive diagnostic biomarker for cerebral infarction.

Comprehensive analysis of core genes and key pathways in Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disease that occurs mostly in middle-aged and older adults. Its main pathological feature is the progressive death of substantia nigra dopaminergic neurons. As the world's population ages, the number of PD patients is increasing. In this study, we explored the relationship between PD and the cell cycle. In this study, we collected two independent PD transcriptomic datasets, GSE54536 and GSE6613, from the Gene Expression Omnibus (GEO) database. Gene set enrichment analysis (GSEA) was used to identify dysregulated pathways in PD samples. Gene expression was verified by qPCR in PD patients. Nineteen pathways were negatively enriched in both the GSE54536 and GSE6613 datasets. Seven of these 19 pathways were cell cycle-related pathways, including the M/G1 transition, S phase, G1/S transition, mitotic G1-G1/S phases, CDT1 association with the CDC6 ORC origin complex, cell cycle checkpoints and synthesis of DNA. Next, we found that eight genes (PSMA4, PSMB1, PSMC5, PSMD11, MCM4, RPA1, POLE, and PSME4) were mainly enriched in the GSE54536 and GSE6613 datasets. In GSE54536, PSMA4, PSMB1, PSMC5, and PSME4 could significantly predict the occurrence of PD, whereas, in GSE6613, RPA1 and PSME4 could significantly predict the occurrence of PD. Only PSME4 showed significant results in both datasets. Finally, we assessed blood samples from PD patients and controls. Compared with the control samples, the PD samples had lower mRNA levels of PSME4. In summary,these findings can significantly enhance our understanding of the causes and potential molecular mechanisms of PD; the cell cycle signaling pathways and PSME4 may be therapeutic targets for PD.

Molecular regulation of ZmMs7 required for maize male fertility and development of a dominant male-sterility system in multiple species.

Understanding the molecular basis of male sterility and developing practical male-sterility systems are essential for heterosis utilization and commercial hybrid seed production in crops. Here, we report molecular regulation by genic male-sterility gene maize male sterility 7 (ZmMs7) and its application for developing a dominant male-sterility system in multiple species. ZmMs7 is specifically expressed in maize anthers, encodes a plant homeodomain (PHD) finger protein that functions as a transcriptional activator, and plays a key role in tapetal development and pollen exine formation. ZmMs7 can interact with maize nuclear factor Y (NF-Y) subunits to form ZmMs7-NF-YA6-YB2-YC9/12/15 protein complexes that activate target genes by directly binding to CCAAT box in their promoter regions. Premature expression of ZmMs7 in maize by an anther-specific promoter p5126 results in dominant and complete male sterility but normal vegetative growth and female fertility. Early expression of ZmMs7 downstream genes induced by prematurely expressed ZmMs7 leads to abnormal tapetal development and pollen exine formation in p5126-ZmMs7 maize lines. The p5126-ZmMs7 transgenic rice and Arabidopsis plants display similar dominant male sterility. Meanwhile, the mCherry gene coupled with p5126-ZmMs7 facilitates the sorting of dominant sterility seeds based on fluorescent selection. In addition, both the ms7-6007 recessive male-sterility line and p5126-ZmMs7M dominant male-sterility line are highly stable under different genetic germplasms and thus applicable for hybrid maize breeding. Together, our work provides insight into the mechanisms of anther and pollen development and a promising technology for hybrid seed production in crops.