Talaromides A-C, Bioactive Cyclic Heptapeptides from Talaromyces siglerae Isolated from a Marine Sponge.

Three new cyclic heptapeptides, talaromides A-C (1-3), were isolated from cultures produced by the fungus Talaromyces siglerae (Ascomycota), isolated from an unidentified sponge. The structures, featuring an unusual proline-anthranilic moiety, were elucidated by analysis of spectroscopic data and chemical transformations, including the advanced Marfey's method and GITC derivatization. Talaromides A and B inhibited migration activity against PANC-1 human pancreatic cancer cells without significant cytotoxicity.

Prognostic Analysis of Lactic Acid Metabolism Genes in Oral Squamous Cell Carcinoma.

OBJECTIVES: Oral squamous cell carcinoma (OSCC) is the most common malignant tumour in the oral and maxillofacial region. Lactic acid accumulation in the tumour microenvironment (TME) has gained attention for its dual role as an energy source for cancer cells and an activator of signalling pathways crucial to tumour progression. This study aims to reveal the impact of lactate-related genes (LRGs) on the prognosis, TME, and immune characteristics of OSCC, with the ultimate goal of developing a novel prognostic model. METHODS: Unsupervised clustering analysis of LRGs in OSCC patients from The Cancer Genome Atlas database was conducted to evaluate and compare TME, immune features, and clinical characteristics across various lactate subtypes. A refined prognostic model was developed through the application of Cox and Least absolute shrinkage and selection operator (LASSO) regression techniques. External validation sets were then utilised to improve model accuracy, along with a detailed correlation analysis of drug sensitivity. RESULTS: The Cancer Genome Atlas-OSCC patients were categorised into 4 distinct lactate subtypes based on LRGs. Notably, patients in subtype 1 and subtype 2 exhibited the least and most favourable prognoses, respectively. Subtype 1 patients showed elevated expression levels of immune checkpoint genes. Further analysis identified 1086 genes with significant expression differences between cancer and noncancer tissues, as well as between subtype 1 and subtype 2 patients. Selected genes for the prognostic model included ZNF662, CGNL1, VWCE, and ZFP42. The high-risk group defined by this model had a significantly poorer prognosis (P < .0001) and functioned as an independent prognostic factor (P < .001), accurately predicting 1-, 3-, and 5-year survival rates. Additionally, individuals in the high-risk category exhibited heightened sensitivity to chemotherapy drugs such as AZ6102 and Venetoclax. CONCLUSIONS: The predictive model based on the genes ZNF662, CGNL1, VWCE, and ZFP42 can serve as a reliable biomarker, providing accurate prognostic predictions for OSCC patients and potential opportunities for pharmaceutical interventions.

Cavomycins A-C, Linear Oligomer Depsipeptides from an Annelid-Associated Streptomyces cavourensis.

Three unique linear oligomeric depsipeptides, designated as cavomycins A-C (1-3), were identified from Streptomyces cavourensis, a gut bacterium associated with the annelid Paraleonnates uschakovi. The structures of these depsipeptides were determined through a combination of spectroscopic methods and chemical derivatization techniques, including methanolysis, the modified Mosher's method, advanced Marfey's methods, and phenylglycine methyl ester derivatization. The unique dipeptidyl residue arrangements in compounds 1-3 indicate that they are not degradation products of valinomycin. Compound 2 and its methylation derivative 2a exhibited antiproliferative activity against PANC-1 pancreatic cancer cells with IC50 values of 1.2 and 1.7 µM, respectively.

Apolipoprotein E E3/E4 genotype is associated with an increased risk of type 2 diabetes mellitus complicated with coronary artery disease.

OBJECTIVE: Dyslipidemia is a co-existing problem in patients with diabetes mellitus (DM) and coronary artery disease (CAD), and apolipoprotein E (APOE) plays an important role in lipid metabolism. However, the relationship between the APOE gene polymorphisms and the risk of developing CAD in type 2 DM (T2DM) patients remains controversial. The aim of this study was to assess this relationship and provide a reference for further risk assessment of CAD in T2DM patients. METHODS: The study included 378 patients with T2DM complicated with CAD (T2DM + CAD) and 431 patients with T2DM alone in the case group, and 351 individuals without DM and CAD were set as controls. The APOE rs429358 and rs7412 polymorphisms were genotyped by polymerase chain reaction (PCR) - microarray. Differences in APOE genotypes and alleles between patients and controls were compared. Multiple logistic regression analysis was performed after adjusting for age, gender, body mass index (BMI), history of smoking, and history of drinking to access the relationship between APOE genotypes and T2DM + CAD risk. RESULTS: The frequencies of the APOE ɛ3/ɛ4 genotype and ε4 allele were higher in the T2DM + CAD patients, and the frequencies of the APOE ɛ3/ɛ3 genotype and ε3 allele were lower than those in the controls (all p < 0.05). The T2DM + CAD patients with ɛ4 allele had higher level in low-density lipoprotein cholesterol (LDL-C) than those in patients with ɛ2 and ɛ3 allele (p < 0.05). The results of logistic regression analysis showed that age ≥ 60 years old, and BMI ≥ 24.0 kg/m2 were independent risk factors for T2DM and T2DM + CAD, and APOE ɛ3/ɛ4 genotype (adjusted odds ratio (OR) = 1.93, 95% confidence interval (CI) = 1.18-3.14, p = 0.008) and ɛ4 allele (adjusted OR = 1.97, 95% CI = 1.23-3.17) were independent risk factors for T2DM + CAD. However, the APOE genotypes and alleles were not found to have relationship with the risk of T2DM. CONCLUSIONS: APOE ε3/ε4 genotype and ε4 allele were independent risk factors for T2DM complicated with CAD, but not for T2DM.

Comparative clinical study of phosphorous necrosis and medical-related osteonecrosis of the jaws.

BACKGROUND: Phosphorous necrosis of the jaw (PNJ) exhibits similar clinical and pathological features as medical-related osteonecrosis of the jaw (MRONJ). This study aims at comparing the similarities and differences between PNJ and MRONJ regarding pathological features and to provide a theoretical basis for the clinical diagnosis and management of PNJ. MATERIAL AND METHODS: A retrospective analysis was conducted to assess clinical differences among 38 PNJ patients and 31 MRONJ patients, who were diagnosed and treated between January 2009 and October 2022. Pathological alterations in bone tissue were evaluated using EDS, H&E, Masson, and TRAP staining on five specimens from both MRONJ and PNJ cases; furthermore, immunohistochemistry was used to determine the expression levels of OPG, RANKL, and Runx2. The mandibular coronoid process was removed from individuals with temporomandibular joint ankylosis to serve as a control. RESULTS: CBCT imaging demonstrated necrotic bone formation in block, strip, or plaque shapes. EDS analysis showed that the calcium/phosphorus ratio in the bone tissue of PNJ and MRONJ was significantly lower than that of the control group (P < 0.05). Additionally, staining indicated reduced osteoblast counts, disrupted bone trabecular structure, and decreased collagen fiber content in the bone tissues of PNJ and MRONJ. Immunohistochemistry demonstrated that RANKL expression was significantly lower in MRONJ compared to PNJ and control groups (P < 0.05). Conversely, Runx2 expression was significantly higher in PNJ than in MRONJ and control groups (P < 0.05), and there was no significant difference in OPG expression. CONCLUSION: PNJ and MRONJ demonstrate comparable clinical manifestations and pathological traits, although disparities may exist in their underlying exhibit comparable clinical manifestations, pathological traits, and molecular mechanisms.

Treatment for Gorham-Stout syndrome with a combination of teriparatide and denosumab.

Gorham-Stout syndrome is an aggressive, non-hereditary, and rare disease affecting bone metabolism. Its etiology and pathogenesis remain elusive. The syndrome manifests with diverse clinical symptoms, often leading to frequent misdiagnoses and presenting challenges in treatment. In this study, we report a case of cranial and maxillary osteolysis in a 47-year-old female patient with somatic mutations in the VEGF-A, VEGF-B, and VEGF-C genes and the EPHB4 gene. After treatment with bisphosphonates, this patient still had persistent resorption of the mandible, but switching to a teriparatide and denosumab combination yielded substantial improvement. This study is the first report to show that teriparatide combined with denosumab can be used to treat Gorham-Stout syndrome.

Radiation injury and gut microbiota-based treatment.

The exposure to either medical sources or accidental radiation can cause varying degrees of radiation injury (RI). RI is a common disease involving multiple human body parts and organs, yet effective treatments are currently limited. Accumulating evidence suggests gut microbiota are closely associated with the development and prevention of various RI. This article summarizes 10 common types of RI and their possible mechanisms. It also highlights the changes and potential microbiota-based treatments for RI, including probiotics, metabolites, and microbiota transplantation. Additionally, a 5P-Framework is proposed to provide a comprehensive strategy for managing RI.

The Challenging Path to Diagnosing Extraintestinal Amoebiasis: A Case Report of an HIV-Infected Patient.

Background: Amoebiasis, an infectious disease caused by the parasitic protozoan E. histolytica, is easily misdiagnosed due to its declining incidence and atypical symptoms. Case Presentation: A 31-year-old male presented to the hospital with dyspnea and inability to lie flat. Imaging studies indicated a large amount of pleural effusion on the right side and multiple huge cysts in the liver. The patient underwent liver tumor resection surgery at another hospital due to suspected malignancy, but no evidence of relevant malignant tumors was found in the pathological examination. Subsequently, we performed metagenomic next-generation sequencing on the liver drainage fluid and obtained liver pathology slides from the hospital where the surgery was performed at that time. Both of them confirmed the diagnosis of amoebic infection. Empirical treatment with metronidazole was initiated before the diagnosis was confirmed, along with symptomatic treatments such as thoracic drainage and liver drainage. Eventually, the patient's condition improved and he was discharged smoothly. Conclusion: In order to avoid misdiagnosis of amoebiasis, thoroughly inquiring about the patient's medical history, shifting perspectives and continuing investigating are necessary when one diagnostic approach proves ineffective. Besides, interdisciplinary collaboration and persistent efforts are crucial for accurate diagnosis.

Liver Regeneration-Related Genes of Nontumor Liver Tissues Predict the Prognosis of Patients with Hepatocellular Carcinoma.

Background: Hepatocellular carcinoma (HCC) is one of the most serious malignant tumors threatening human life with a high mortality rate. The liver regenerative capacity after hepatectomy in early-stage HCC patients is influenced by various factors, including surgical methods and energy metabolism. This study aims to provide a prognostic model based on genes related to liver regeneration that can predict the prognosis of non-tumor tissues in HCC patients. Patients and Methods: A total of 584 non-tumor tissues from HCC patients were collected from three independent databases. Kaplan-Meier survival curves were used to identify prognostic liver-regeneration genes. Subsequently, a prognostic indicator, designated as the Liver Regeneration score (LR score), was determined using single-sample gene set enrichment analysis (ssGSEA). Independent cohorts were used to verify the relationship between LR score and prognosis in non-tumor tissues of HCC patients. Furthermore, a liver regeneration-related model was established to validate key genes identified through LASSO Cox regression analysis. Results: We constructed a gene set comprising 24 liver regeneration-related genes, and the LR score was utilized to predict the prognosis of HCC patients based on its levels in non-tumor tissues. In non-tumor tissues of HCC patients, higher LR scores were associated with improved prognosis. Higher LR scores in non-tumor tissues indicate improved liver metabolism in HCC patients, revealed by Enrichment analysis. LASSO Cox regression analysis identified two key genes, DHTKD1 (dehydrogenase E1 and transketolase domain containing 1) and PHYH (phytanoyl-CoA 2-hydroxylase), and higher expression levels of these genes in non-tumor tissues were correlated with better prognosis. The expression levels of these two genes also changed corresponding to the progression of liver regeneration. Conclusion: In summary, our study has introduced a novel LR gene signature for HCC patients, providing a predictive model for estimating clinical prognosis from non-tumor tissues. The LR score demonstrates promise as a reliable indicator for predicting overall survival in HCC.

MiR-3529-3p from PDGF-BB-induced cancer-associated fibroblast-derived exosomes promotes the malignancy of oral squamous cell carcinoma.

AIMS: This study aims to explore the role of exosomes from cancer-associated fibroblasts (CAFs) induced by PDGF-BB in promoting the malignancy of oral squamous cell carcinoma (OSCC) and provide new insight into the mechanism of OSCC progression and its treatment. MAIN METHODS: Exosomes were extracted from human oral mucosa fibroblasts (hOMFs) and CAFs. Differentially expressed miRNAs of exosomes between hOMFs and CAFs were analysed using high-throughput sequencing and self-programmed R software. Cal-27, a human tongue squamous carcinoma cell line, was treated with exosomes. Differentially expressed miRNAs between clinical cancer tissues and adjacent tissues and between hOMF and CAF exosomes were verified by qRT‒PCR. The effect of miR-3529-3p on Cal-27 cells was clarified by overexpressing or knocking down miR-3529-3p in Cal-27 cells. Sample expression and differentially expressed miRNA expression were compared between cancer and paracarcinoma tissues. KEY FINDINGS: We found that exosomes from CAFs (CAF-Exos) were internalized by tongue squamous carcinoma cells and promoted their proliferation, migration, invasion, and antiapoptotic effects. MiR-3529-3p was a significant differentially expressed miRNA between CAF-Exos and exosomes from hOMFs (hOMF-Exos). The overexpression of miR-3529-3p promoted proliferation, migration, and invasion and inhibited apoptosis of Cal-27 cells. SIGNIFICANCE: This study explores the role of PDGF-BB-induced CAFs in promoting malignancy in OSCC. This study will provide new insight into the mechanism of OSCC progression and its treatment.

Discovery and optimized extraction of the anti-osteoclastic agent epicatechin-7-O-ß-D-apiofuranoside from Ulmus macrocarpa Hance bark.

Ulmus macrocarpa Hance bark (UmHb) has been used as a traditional herbal medicine in East Asia for bone concern diseases for a long time. To find a suitable solvent, we, in this study, compared the efficacy of UmHb water extract and ethanol extract which can inhibit osteoclast differentiation. Compared with two ethanol extracts (70% and 100% respectively), hydrothermal extracts of UmHb more effectively inhibited receptor activators of nuclear factor κB ligand-induced osteoclast differentiation in murine bone marrow-derived macrophages. We identified for the first time that (2R,3R)-epicatechin-7-O-ß-D-apiofuranoside (E7A) is a specific active compound in UmHb hydrothermal extracts through using LC/MS, HPLC, and NMR techniques. In addition, we confirmed through TRAP assay, pit assay, and PCR assay that E7A is a key compound in inhibiting osteoclast differentiation. The optimized condition to obtain E7A-rich UmHb extract was 100 mL/g, 90 °C, pH 5, and 97 min. At this condition, the content of E7A was 26.05 ± 0.96 mg/g extract. Based on TRAP assay, pit assay, PCR, and western blot, the optimized extract of E7A-rich UmHb demonstrated a greater inhibition of osteoclast differentiation compared to unoptimized. These results suggest that E7A would be a good candidate for the prevention and treatment of osteoporosis-related diseases.

Extracellular matrix of ameloblastoma-derived negatively regulates osteogenic differentiation.

OBJECTIVE: To investigate the effects of key pathogenic genes involved in the development of jaw ameloblastoma (AB) and its associated extracellular matrix (ECM) on osteogenic differentiation in order to provide a theoretical foundation for future research into bone aggressiveness of AB. METHODS: The essential genes were identified by five AB patients for whole-exome sequencing and the microarray datasets GES38494 and GES132472. Moreover, the expression of key genes and their encoded proteins in AB tissues was explored. In addition, AB-derived the decellularized ECM (ABdECM) tissues were generated by the decellularization technique. Furthermore, the osteogenic development of periodontal ligament stem cells (PDLSCs) was mimicked by simulating the effects of the AB tumor microenvironment (TME). RESULTS: The AB essential genes including COL1A2, COL4A2, FBN1, and HPSE were discovered. Among them, the expression of HPSE was down-regulated, while that of COL1A2, COL4A2, and FBN1 was noticeably upregulated in AB compared with normal gingival tissues of the jaws. In vitro osteogenic differentiation of PDLSCs was suppressed by the ABdECM. CONCLUSIONS: Abnormal ECM proteins encoded by COL4A2, COL1A2, FBN1, and HPSE genes can cause disturbance in the ECM environment of AB and promote bone resorption.

Soluble CD4 effectively prevents excessive TLR activation of resident macrophages in the onset of sepsis.

T lymphopenia, occurring in the early phase of sepsis in response to systemic inflammation, is commonly associated with morbidity and mortality of septic infections. We have previously shown that a sufficient number of T cells is required to constrain Toll-like receptors (TLRs) mediated hyperinflammation. However, the underlying mechanisms remains unsolved. Herein, we unveil that CD4+ T cells engage with MHC II of macrophages to downregulate TLR pro-inflammatory signaling. We show further that the direct contact between CD4 molecule of CD4+ T cells or the ectodomain of CD4 (soluble CD4, sCD4), and MHC II of resident macrophages is necessary and sufficient to prevent TLR4 overactivation in LPS and cecal ligation puncture (CLP) sepsis. sCD4 serum concentrations increase after the onset of LPS sepsis, suggesting its compensatory inhibitive effects on hyperinflammation. sCD4 engagement enables the cytoplasmic domain of MHC II to recruit and activate STING and SHP2, which inhibits IRAK1/Erk and TRAF6/NF-κB activation required for TLR4 inflammation. Furthermore, sCD4 subverts pro-inflammatory plasma membrane anchorage of TLR4 by disruption of MHC II-TLR4 raft domains that promotes MHC II endocytosis. Finally, sCD4/MHCII reversal signaling specifically interferes with TLR4 but not TNFR hyperinflammation, and independent of the inhibitive signaling of CD40 ligand of CD4+ cells on macrophages. Therefore, a sufficient amount of soluble CD4 protein can prevent excessive inflammatory activation of macrophages via alternation of MHC II-TLR signaling complex, that might benefit for a new paradigm of preventive treatment of sepsis.

Bioactive Piperazic Acid-Bearing Cyclodepsipeptides, Lydiamycins E-H, from an Endophytic Streptomyces sp. Associated with Cinnamomum cassia.

A chemical investigation of the endophytic Streptomyces sp. HBQ95, associated with the medicinal plant Cinnamomum cassia Presl, enabled the discovery of four new piperazic acid-bearing cyclodepsipeptides, lydiamycins E-H (1-4), and one known compound (lydiamycin A). Their chemical structures, including absolute configurations, were defined by a combination of spectroscopic analyses and multiple chemical manipulations. Lydiamycins F-H (2-4) and A (5) exhibited antimetastatic activity against PANC-1 human pancreatic cancer cells without significant cytotoxicity.

Study on the effectiveness of modified colonoscopy nursing pads in colonoscopy.

OBJECTIVE: To investigate the effect of modified colonoscopy nursing pads in colonoscopy. METHODS: A total of 262 subjects who underwent colonoscopy at our endoscopy center between September 1, 2021 and February 28, 2022 were selected and randomly divided into a control group and an experimental group, with 131 cases in each group. The control group used conventional nursing pads, while the experimental group used modified nursing pads. The success rate of the first correct position, the time spent by the nurse to guide the correct position, the bed unit contamination rate, the contamination rate of the operator's protective equipment, the privacy protection of the examinees and the satisfaction degree after the examination were compared between the two groups. RESULTS: The success rate of the first correct position of the examinees in the experimental group was significantly higher than that of the control group (P < 0.05), and the time spent by the nurses to guide the correct position in the experimental group was less than that of the control group (P < 0.05). The bed unit contamination rate and operator's protective equipment contamination rate of the experimental group were lower than those of the control group, and the satisfaction degree of the examinees was higher in the experimental group than in the control group, and the differences were statistically significant (P < 0.05). CONCLUSION: The modified colonoscopy nursing pad can save the time of correct colonoscopy positioning of examinees, improve the efficiency of colonoscopy, reduce the workload of nursing staff, effectively protect the privacy of patients, reduce the bed unit contamination and protective equipment contamination, and then improve the comfort and satisfaction of patients.

Mobilizing phospholipids on tumor plasma membrane implicates phosphatidylserine externalization blockade for cancer immunotherapy.

In "healthy" tumor cells, phosphatidylserine (PS) is predominately localized in the inner plasma membrane leaflet. During apoptosis, PS relocates to the outer leaflet. Herein, we established PSout tumor models with tumor cells lacking PS flippase component CDC50A, constantly exposing PS but alive. PSout tumors developed bigger than wild-type (WT) tumors, featuring M2 polarized tumor-associated macrophages (TAMs) and fewer tumor-antigen-specific T cells. The PS receptor TIM-3 is responsible for PS recognition. Employing an opposite tumor model, PSin, with tumor cells lacking the PS scramblase Xkr8 and unable to expose PS during otherwise normal apoptosis, we find that the accumulated apoptotic tumor cells produce and release cyclic GAMP (cGAMP) to immune cells to activate the STING pathway, leading to TAM M1 polarization, suppressed interleukin (IL)-10 secretion, and natural killer (NK) cell cytotoxicity. Silencing Xkr8 in vivo by either short hairpin RNA (shRNA) or small interfering RNA (siRNA) to achieve a PS externalization blockade provides robust therapeutic anti-tumor efficiency.

Effect of high-quality nursing on orthopedic trauma based on a fast-track surgery model.

OBJECTIVE: To explore the effect of fast-track surgery (FTS) based high quality nursing on orthopedic trauma. METHODS: In this retrospective study, 94 patients who received orthopedic trauma surgery in our hospital from December 2018 to November 2020 were included. The patients were assigned to a research group (n=47) or a control group (n=47) according to which nursing method they received. The control group received routine nursing, while the research group also received FTS-based high-quality nursing. Perioperative situation, quality of life score (SF-36) before and after operation, incidence of complications, pain score (VAS) at different time periods after operation, and nursing satisfaction were compared between the two groups. RESULTS: There was no significant difference in operation time or blood loss between groups (P>0.05). The time to getting out of bed for the first time, time to drainage tube removal, and length of hospital stay in the research group were shorter than those in the control group (P<0.001). Repeated measurement analysis of variance revealed that the VAS score of the research group was lower than that of the control group at 1 h, 3 h, 6 h, 24 h and 48 h after operation (P<0.05). Intra-group comparison manifested that the VAS scores of both groups decreased at 1 h, 3 h, 6 h, 24 h and 48 h after operation (P<0.05). Comparison at different time points revealed that the difference was statistically significant (P<0.05). The incidence of complications in the research group (4.26%) was lower than that in the control group (17.02%; P<0.05). The satisfaction rate of nursing in the research group (93.62%) was higher than that in the control group (78.72%; P<0.05). After intervention, the level of superoxide dismutase (SOD) and glutathione (GSH) in both groups decreased with a lesser decrease in the research group. The contents of reactive oxygen species (ROS) and malondialdehyde (MDA) in groups after intervention were higher than those before intervention with a milder increase in the research group. CONCLUSION: FTS mode can shorten the recovery time, reduce the degree of pain and the reduce the time of analgesia. It also promotes the recovery and shortens the hospital stay of patients, and improves their quality of life, with high satisfaction. This may be related to an expeditedd surgical process and reduced oxidative stress response of patients undergoing surgery under the rapid recovery surgical model.

The efficacy and tolerability of sports drink versus water in bowel preparations: a randomised controlled study.

BACKGROUND: An optimal bowel preparation can result in an improved colonoscopy. This study was to compare the effectiveness and safety of the use of a sports drink (Mizone) plus polyethylene glycol (PEG) solution with a water plus PEG solution in bowel preparations. METHODS: This was a randomised controlled study. All of the included patients were randomly divided into the following two groups: the PEG + Mizone group and the PEG + water group. The palatability of the solution was measured through the use of questionnaires. Additionally, bowel cleanliness was evaluated according to the Ottawa Bowel Preparation Scale (OBPS, 0-14, with higher values indicating worse cleanliness), as well as with the aid of colonoscopy videos. RESULTS: A total of 270 patients were enrolled. The rate of adequate bowel preparation was 74.8% in the PEG + Mizone group and 68.9% in the PEG + water group, with a risk difference of 5.9% (95% CI: - 4.8-16.6%), which indicated noninferiority (noninferiority margin: - 9.5% < - 4.8%). However, patients rated the palatability (65.9% vs 44.4%, P < 0.001) and willingness to recommend or repeat (88.9% vs 75.6%, P = 0.004) the administration of the PEG + Mizone preparation as being better than those of the PEG + water preparation. The rates of adverse events during the bowel preparations were not significantly different between the two groups, except for bloating (PEG + Mizone vs PEG + water, 4.4% vs 13.3%, P = 0.010). CONCLUSION: The concomitant use of PEG + Mizone was a well tolerated and effective bowel preparation, compared with the PEG + water treatment. TRIAL REGISTRATION: ClinicalTrials.gov NCT04247386 . Registered on 30 Jan 2020.

Gas Phase and Gas-Solid Interface Ozonolysis of Nitrogen Containing Alkenes: Nitroalkenes, Enamines, and Nitroenamines.

Emerging contaminants are of concern due to their rapidly increasing numbers and potential ecological and human health effects. In this study, the synergistic effects of the presence of multifunctional nitro, amino and carbon-carbon double bond (C═C) groups on the gas phase ozonolysis in O2 or at the air/solid interface were investigated using five simple model compounds. The gas phase ozonolysis rate constants at 296 K were (3.5 ± 0.9) × 10-20 cm3 molecule-1 s-1 for 2-methyl-1-nitroprop-1-ene and (6.8 ± 0.8) × 10-19 cm3 molecule-1 s-1 for 4-methyl-4-nitro-1-pentene, with lifetimes of 134 and 7 days in the presence of 100 ppb ozone in the atmosphere, respectively. The rate constants for gas phase E-N,N-dimethyl-1-propenylamine and N,N-dimethylallylamine reactions with ozone were too fast (>10-18 cm3 molecule-1 s-1) to be measured, implying lifetimes of less than 5 days. A multiphase kinetics model (KM-GAP) was used to probe the gas-solid kinetics of 1-dimethylamino-2-nitroethylene, yielding a rate constant for the surface reaction of 1.8 × 10-9 cm2 molecule-1 s-1 and in the bulk 1× 10-16 cm3 molecule-1 s-1. These results show that a nitro group attached to the C═C lowers the gas phase rate constant by 2-3 orders of magnitude compared to the simple alkenes, while amino groups have the opposite effect. The presence of both groups provides counterbalancing effects. Products with deleterious health effects including dimethylformamide and formaldehyde were identified by FTIR. The identified products differentiate whether the initial site of ozone attack is C═C and/or the amino group. This study provides a basis for predicting the environmental fates of emerging contaminants and shows that both the toxicity of both the parent compounds and the products should be taken into account in assessing their environmental impacts.

Subgenome dominance and its evolutionary implications in crop domestication and breeding.

Polyploidization or whole-genome duplication (WGD) is a well-known speciation and adaptation mechanism in angiosperms, while subgenome dominance is a crucial phenomenon in allopolyploids, established following polyploidization. The dominant subgenomes contribute more to genome evolution and homoeolog expression bias, both of which confer advantages for short-term phenotypic adaptation and long-term domestication. In this review, we firstly summarize the probable mechanistic basis for subgenome dominance, including the effects of genetic [transposon, genetic incompatibility, and homoeologous exchange (HE)], epigenetic (DNA methylation and histone modification), and developmental and environmental factors on this evolutionary process. We then move to Brassica rapa, a typical allopolyploid with subgenome dominance. Polyploidization provides the B. rapa genome not only with the genomic plasticity for adapting to changeable environments, but also an abundant genetic basis for morphological variation, making it a representative species for subgenome dominance studies. According to the 'two-step theory', B. rapa experienced genome fractionation twice during WGD, in which most of the genes responding to the environmental cues and phytohormones were over-retained, enhancing subgenome dominance and consequent adaption. More than this, the pangenome of 18 B. rapa accessions with different morphotypes recently constructed provides further evidence to reveal the impacts of polyploidization and subgenome dominance on intraspecific diversification in B. rapa. Above and beyond the fundamental understanding of WGD and subgenome dominance in B. rapa and other plants, however, it remains elusive why subgenome dominance has tissue- and spatiotemporal-specific features and could shuffle between homoeologous regions of different subgenomes by environments in allopolyploids. We lastly propose acceleration of the combined application of resynthesized allopolyploids, omics technology, and genome editing tools to deepen mechanistic investigations of subgenome dominance, both genetic and epigenetic, in a variety of species and environments. We believe that the implications of genomic and genetic basis of a variety of ecologically, evolutionarily, and agriculturally interesting traits coupled with subgenome dominance will be uncovered and aid in making new discoveries and crop breeding.