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1.
Forensic Sci Int Genet ; 71: 103029, 2024 Mar 05.
Article in English | MEDLINE | ID: mdl-38518712

ABSTRACT

Y-chromosomal short tandem repeat polymorphisms (Y-STRs) and Y-chromosomal single nucleotide polymorphisms (Y-SNPs) are valuable genetic markers used in paternal lineage identification and population genetics. Currently, there is a lack of an effective panel that integrates Y-STRs and Y-SNPs for studying paternal lineages, particularly in East Asian populations. Hence, we developed a novel Y-chromosomal targeted panel called YARN (Y-chromosome Ancestry and Region Network) based on multiplex PCR and a single-end 400 massive parallel sequencing (MPS) strategy, consisting of 44 patrilineage Y-STRs and 260 evolutionary Y-SNPs. A total of 386 reactions were validated for the effectiveness and applicability of YARN according to SWGDAM validation guidelines, including sensitivity (with a minimum input gDNA of 0.125 ng), mixture identification (ranging from 1:1-1:10), PCR inhibitor testing (using substances such as 50 µM hematin, 100 µM hemoglobin, 100 µM humic acid, and 2.5 mM indigo dye), species specificity (successfully distinguishing humans from other animals), repeatability study (achieved 100% accuracy), and concordance study (with 99.91% accuracy for 1121 Y-STR alleles). Furthermore, we conducted a pilot study using YARN in a cohort of 484 Han Chinese males from Huaiji County, Zhaoqing City, Guangdong, China (GDZQHJ cohort). In this cohort, we identified 52 different Y-haplogroups and 73 different surnames. We found weak to moderate correlations between the Y-haplogroups, Chinese surnames, and geographical locations of the GDZQHJ cohort (with λ values ranging from 0.050 to 0.340). However, when we combined two different categories into a new independent variable, we observed stronger correlations (with λ values ranging from 0.617 to 0.754). Overall, the YARN panel, which combines Y-STR and Y-SNP genetic markers, meets forensic DNA quality assurance guidelines and holds potential for East Asian geographical origin inference and paternal lineage analysis.

2.
Cell Mol Biol (Noisy-le-grand) ; 70(2): 67-72, 2024 Feb 29.
Article in English | MEDLINE | ID: mdl-38430042

ABSTRACT

To investigate the expression pattern and prognostic role of m6A RNA methylation regulators in non-small cell lung cancer (NSCLC), we downloaded data from 422 patients from The Cancer Genome Atlas (TCGA) database. The relationship between the expression levels of m6A RNA methylation regulators and clinicopathological variables of NSCLC was analysed using R language. By analysing glioma data in TCGA, we found that a prognostic risk score model could be constructed based on 18 genes with m6A methylation modification. m6A gene alterations were significantly associated with tumour grade and tumour stage. Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression models were used to identify 2 m6A RNA methylation modifiers: IFG2BP2, and METTL14 to construct risk profiles. Based on the risk profile, patients were divided into high-risk and low-risk groups. The overall survival rate of the low-risk group was significantly higher than that of the high-risk group. The results suggest that the prognostic risk score model constructed by m6A methylation regulators can predict the prognosis of glioma patients. IFG2BP2 and METTL14 may be the key m6A methylation regulators involved in the development of NSCLC and can be used as the molecular markers for the prognosis of NSCLC.


Subject(s)
Carcinoma, Non-Small-Cell Lung , Glioma , Lung Neoplasms , Humans , Carcinoma, Non-Small-Cell Lung/diagnosis , Carcinoma, Non-Small-Cell Lung/genetics , RNA Methylation , Prognosis , Lung Neoplasms/diagnosis , Lung Neoplasms/genetics , Glioma/diagnosis , Glioma/genetics , RNA
3.
Front Genet ; 15: 1347868, 2024.
Article in English | MEDLINE | ID: mdl-38317659

ABSTRACT

Introduction: Short Tandem Repeats (STRs) are highly valuable genetic markers in forensic science. However, the conventional PCR-CE technique has limitations, and the emergence of massively parallel sequencing (MPS) technology presents new opportunities for STR analysis. Yet, there is limited research on Chinese population diversity using MPS. Methods: In this study, we obtained genotype data for 52 A-STRs and 81 Y-STRs from the Hakka population in Meizhou, Guangdong, China, using the Forensic Analysis System Multiplecues SetB Kit on the MGISEQ-2000 platform. Results: Our findings demonstrate that these 133 STRs are highly efficient for forensic applications within the Meizhou Hakka population. Statistical analysis revealed Hobs values ranging from 0.61306 to 0.91083 and Hexp values ranging from 0.59156 to 0.91497 for A-STRs based on length polymorphism. For sequence polymorphism, Hobs values ranged from 0.61306 to 0.94586, and Hexp values fluctuated between 0.59156 and 0.94487. The CPE values were 1-5.0779620E-21 and 1-3.257436E-24 for length and sequence polymorphism, respectively, while the CPD values were 1-1.727007E-59 and 1-5.517015E-66, respectively. Among the 80 Y-STR loci, the HD values for length and sequence polymorphism were 0.99764282 and 0.99894195, respectively. The HMP values stood at 0.00418102 and 0.00288427, respectively, and the DC values were 0.75502742 and 0.83363803, respectively. For the 52 A-STR loci, we identified 554 and 989 distinct alleles based on length and sequence polymorphisms, respectively. For the 81 Y-STR loci, 464 and 652 unique alleles were detected at the length and sequence level, respectively. Population genetic analysis revealed that the Meizhou Hakka population has a close kinship relationship with the Asian populations THI and KOR based on length polymorphism data of A-STRs. Conversely, based on length polymorphism data of Y-STRs, the Meizhou Hakka population has the closest kinship relationship with the Henan Han population. Discussion: Overall, the variation information of repeat region sequences significantly enhances the forensic identification efficacy of STR genetic markers, providing an essential database for forensic individual and paternity testing in this region. Additionally, the data generated by our study will serve as a vital resource for research into the genetic structure and historical origins of the Meizhou Hakka population.

4.
J Am Chem Soc ; 146(2): 1580-1587, 2024 Jan 17.
Article in English | MEDLINE | ID: mdl-38166100

ABSTRACT

Lactones are cyclic esters with extensive applications in materials science, medicinal chemistry, and the food and perfume industries. Nature's strategy for the synthesis of many lactones found in natural products always relies on a single type of retrosynthetic strategy, a C-O bond disconnection. Here, we describe a set of laboratory-engineered enzymes that use a new-to-nature C-C bond-forming strategy to assemble diverse lactone structures. These engineered "carbene transferases" catalyze intramolecular carbene insertions into benzylic or allylic C-H bonds, which allow for the synthesis of lactones with different ring sizes and ring scaffolds from simple starting materials. Starting from a serine-ligated cytochrome P450 variant previously engineered for other carbene-transfer activities, directed evolution generated a variant P411-LAS-5247, which exhibits a high activity for constructing a five-membered ε-lactone, lactam, and cyclic ketone products (up to 5600 total turnovers (TTN) and >99% enantiomeric excess (ee)). Further engineering led to variants P411-LAS-5249 and P411-LAS-5264, which deliver six-membered δ-lactones and seven-membered ε-lactones, respectively, overcoming the thermodynamically unfavorable ring strain associated with these products compared to the γ-lactones. This new carbene-transfer activity was further extended to the synthesis of complex lactone scaffolds based on fused, bridged, and spiro rings. The enzymatic platform developed here complements natural biosynthetic strategies for lactone assembly and expands the structural diversity of lactones accessible through C-H functionalization.


Subject(s)
Cytochrome P-450 Enzyme System , Lactones , Lactones/chemistry , Catalysis , Cytochrome P-450 Enzyme System/chemistry , Methane
6.
Eval Health Prof ; : 1632787231172277, 2023 Apr 24.
Article in English | MEDLINE | ID: mdl-37092358

ABSTRACT

The impact of multi-point nursing strategies drawing on a problem-solving clinical framework to examine adverse events associated with thyroid nodule resection was investigated. Patients (n = 98) who underwent thyroid nodule resection were divided into observation and control groups. Patients in the control group received conventional care, and patients in the observation group received a multi-point care strategy under a clinical problem-solving framework. The length of stay (p < .001), hospitalization cost (p < .001), nursing satisfaction scores (p < .001) of the observation group were longer or higher and statistically significant. The incidence of complications in the observation group (8.16%) was lower than that in the control group (22.45%). The incidence of adverse events in the observation group (2.04%) was lower than that in the control group (14.29%), and statistically significant (p < .05). The multi-point nursing strategy using a clinical problem-solving framework provided evidence that it shortened the length of stay, reduce hospitalization costs, improve psychological status, increase nursing satisfaction, and reduce complications and adverse events in patients undergoing thyroid nodule resection.

7.
Nat Protoc ; 18(2): 626-657, 2023 02.
Article in English | MEDLINE | ID: mdl-36434097

ABSTRACT

N6-methyladenosine (m6A) is the most abundant mRNA modification in mammalian cells, regulating many physiological processes. Here we describe a method for base-resolution, quantitative m6A sequencing in the whole transcriptome. The enzyme and small-molecule cofactor used in this protocol are prepared by recombinant protein expression and organic synthesis, respectively. Then the library can be prepared from various types of RNA samples using a ligation-based strategy, with m6A modifications being labeled by the enzyme and cofactor. Detailed instructions on ensuing data analysis are also included in this protocol. The method generates highly reproducible results, uncovering 31,233-129,263 sites using as little as 2 ng of poly A+ RNA. These identified sites correspond well with previous m6A profiling results, covering over 65% of peaks detected by the antibody-based approaches. Compared with other currently available methods, this method can be applied to various types of biological samples, including fresh and frozen tissues as well as formalin-fixed paraffin-embedded samples, providing a quantitative method to uncover new insights into m6A biology. The protocol requires basic expertise in molecular biology, recombinant protein expression and organic synthesis. The whole protocol can be done in 15 days, with the library preparation taking 5 days.


Subject(s)
Gene Expression Profiling , Transcriptome , Animals , Gene Expression Profiling/methods , RNA/genetics , Gene Library , Sequence Analysis, RNA/methods , Mammals/genetics
8.
Angew Chem Int Ed Engl ; 61(26): e202203343, 2022 Jun 27.
Article in English | MEDLINE | ID: mdl-35437891

ABSTRACT

Herein, we report the development of a method for highly regio-, stereo-, and enantioselective B-H bond insertion reactions of α-silylcarbenes generated from 1-silylcyclopropenes in the presence of a chiral copper(I)/bisoxazoline catalyst for the construction of chiral γ,γ-disubstituted allylic gem-silylboranes, which cannot be prepared by any other known methods. This reaction is the first highly enantioselective carbene insertion reaction of α-silylcarbenes ever to be reported. The method shows general applicability for various 3,3-disubstituted silylcyclopropenes and exclusively affords E-products. The novel chiral γ,γ-disubstituted allylic gem-silylborane products are versatile allylic bimetallic reagents with high stability and have great synthetic potential, especially for the construction of complex molecules with continuous chiral centers.

9.
Andrology ; 10(5): 894-909, 2022 07.
Article in English | MEDLINE | ID: mdl-35438843

ABSTRACT

BACKGROUND: Aromatase inhibitors (AIs) have been used to treat male infertility for decades. However, due to the lack of large-scale randomized controlled studies and basic research, the efficacy and safety of AIs in the treatment of male infertility remain controversial. Therefore, it is necessary to conduct an evidence-based preliminary evaluation of the existing clinical trials of AIs in the treatment of male infertility. METHOD: A comprehensive literature search was performed in the PubMed, Embase, Cochrane, CNKI, VIP, CBM, and Wanfang databases through August 2021 for all studies. We conducted a systematic review with a meta-analysis of all available studies reporting sperm conventional parameters, gonadotropin and testosterone levels, and/or the pregnancy rate. RESULTS: A total of 10 studies involving 666 patients were included. Letrozole (LE) or anastrozole (AZ) administration significantly increased sperm concentration, total sperm count, serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T) levels, and the testosterone-to-estradiol ratio (T/E2), but E2 levels were significantly reduced compared with baseline values. Compared with the control group, which included selective estrogen receptor modulators (SEMRs) or human chorionic gonadotropin (HCG), LE, or AZ did not have any significant effect on sperm concentration, motility, and morphology, except that AIs had less effect on sperm motility than the control group (weighted mean difference [WMD]: -2.55; 95% CI: -4.11 to -1.00; p = 0.001). CONCLUSION: AIs may be effective in the treatment of male infertility. For infertile male patients planning assisted reproduction, discontinuation of AIs for 2-7 days prior to sperm retrieval may increase the success rate of fertilization. Further studies with larger sample sizes are needed to validate these findings.


Subject(s)
Infertility, Male , Testosterone , Anastrozole/adverse effects , Estradiol , Female , Follicle Stimulating Hormone , Humans , Infertility, Male/drug therapy , Letrozole/adverse effects , Male , Pregnancy , Semen , Sperm Motility , Testosterone/adverse effects
10.
Article in English | MEDLINE | ID: mdl-34491827

ABSTRACT

Lung adenocarcinoma (ADC) is a common subtype of non-small cell lung cancer. MicroRNAs have been reported to be effective biomarkers for diagnosis and an important target for therapy. MiR-4429 is a newly identified miRNA, which can take part in tumor progression as a tumor inhibitor. Moreover, it is an exosomal miRNA that can be taken by lung ADC cell line A549. Nevertheless, its role in lung ADC has been poorly studied. This research discovered that miR-4429 was low expressed in lung ADC cells. MiR-4429 mimics could alleviate the capacities of cell proliferation and metastasis. The mimics are able to reverse epithelial-mesenchymal transition at the same time. Furthermore, it was verified that miR-4429 could bind to ß-catenin and negatively regulate ß-catenin expression. Interestingly, SKL2001 can reverse the role of miR-4429 on tumor. Consequently, miR-4429 can inactivate Wnt/ß-catenin signaling pathway by targeting ß-catenin and prevent oncogene expression in lung ADC cells.

11.
Angew Chem Int Ed Engl ; 60(45): 24214-24219, 2021 Nov 02.
Article in English | MEDLINE | ID: mdl-34476881

ABSTRACT

The scarcity of reliable methods for synthesizing chiral gem-diarylmethine borons limits their applications. Herein, we report a method for highly enantioselective dirhodium-catalyzed B-H bond insertion reactions with diaryl diazomethanes as carbene precursors. These reactions afforded chiral gem-diarylmethine borane compounds in high yield (up to 99 % yield), high activity (turnover numbers up to 14 300), high enantioselectivity (up to 99 % ee) and showed unprecedented broad functional group tolerance. The borane compounds synthesized by this method could be efficiently transformed into diaryl methanol, diaryl methyl amine, and triaryl methane derivatives with good stereospecificity. Mechanistic studies suggested that the borane adduct coordinated to the rhodium catalyst and thus interfered with decomposition of the diazomethane, and that insertion of a rhodium carbene (generated from the diaryl diazomethane) into the B-H bond was most likely the rate-determining step.

12.
Anticancer Drugs ; 32(3): 248-256, 2021 03 01.
Article in English | MEDLINE | ID: mdl-33534411

ABSTRACT

Sesamin, a lignan compound, exhibits a variety of biological activities and possesses potent anticancer properties on some human cancers. However, its effect on human colorectal cancer (CRC) remains to be elucidated. To investigate the effects of sesamin on CRC cells and further to explore the mechanisms, cell viability, cell cycle and apoptosis assays were performed in this study. We found that sesamin had a selective antiproliferation of CRC cell line HCT116 in a dose- and time-dependent manner, but no obvious effect on human normal colorectal mucosa epithelial cell FHC. Further study showed that sesamin-induced cell cycle arrest and decreased the expression of Cyclin D1 significantly and dose-dependently in HCT116 cells. Moreover, sesamin dose-dependently triggered apoptosis of HCT116 but not FHC, and promoted the expression levels of proapoptotic biomarkers Bax, cleaved caspase-3 and cleaved PARP-1 and inhibited the expression of antiapoptotic biomarker Bcl-2. Western blot analysis was used to reveal the possible signaling pathways, and we found that sesamin upregulated the phosphorylation expression levels of C-Jun N-terminal kinase (JNK) and p38 except ERK1/2 in a dose-dependent way in both HCT116 and another CRC cell line SW480. Moreover, we found that the apoptosis effect induced by sesamin was partially eliminated by inhibiting JNK or p38 activation. Finally, we showed that sesamin effectively reduced the growth of xenograft tumors derived from cell lines with limited toxicity. Taken together, the potential ability of sesamin to induce cell cycle arrest and apoptosis was shown to be via the p38 and JNK mitogen-activated protein kinase signaling pathways, which may be one of the mechanisms of the anticancer activity of this low-toxic agent.


Subject(s)
Antioxidants/pharmacology , Dioxoles/pharmacology , JNK Mitogen-Activated Protein Kinases/drug effects , Lignans/pharmacology , p38 Mitogen-Activated Protein Kinases/drug effects , Animals , Apoptosis/drug effects , Cell Cycle/drug effects , Cell Cycle Checkpoints/drug effects , Cell Line, Tumor , Cell Survival , Colorectal Neoplasms , Cyclin D1/drug effects , Dose-Response Relationship, Drug , Humans , JNK Mitogen-Activated Protein Kinases/metabolism , Mice , Mice, Inbred BALB C , Signal Transduction/drug effects , Time Factors , Up-Regulation , p38 Mitogen-Activated Protein Kinases/metabolism
13.
J Am Soc Mass Spectrom ; 32(9): 2306-2312, 2021 Sep 01.
Article in English | MEDLINE | ID: mdl-33561341

ABSTRACT

The photochemistry of α-keto acids has been of great interest due to its implications in atmospheric and prebiotic chemistries. α-Keto acids with long alkyl chains are amphiphilic in nature, and they tend to partition at the air-water interface of atmospheric water droplets and add to the complexity of the chemistries therein. The air-water interface is a unique environment that plays a vital role in overall atmospheric processes. However, existing studies mostly focus on the photochemistry of α-keto acids in the bulk solution and neglect the reactions that occur at the interface. In this study, using the field-induced droplet ionization mass spectrometry methodology that is capable of selectively sampling amphiphilic molecules that reside at the air-water interface, we show that the acid-mediated photochemistry of 2-oxooctanoic acid and 2-oxoheptoic acid is highly different from those of previously reported reactions in the bulk and contributes to the formation of humic-like substances (HULIS). This work emphasizes the uniqueness of the photochemistry at the air-water interface. We anticipate that studies of atmosphere-relevant photochemistry at the air-water interface will be an avenue rich with opportunities.

14.
Zhonghua Nan Ke Xue ; 26(9): 826-831, 2020 Sep.
Article in Chinese | MEDLINE | ID: mdl-33377708

ABSTRACT

OBJECTIVE: To investigate the effect of Bushen Huoxue Recipe (BHR) on cyclophosphamide-induced apoptosis of testicular spermatogenic cells in mice and its possible action mechanisms. METHODS: Fifty male Babl/c mice aged 8-9 weeks were randomly divided into five groups of an equal number: blank control, model control, low-dose BHR, medium-dose BHR and high-dose BHR. The animals in the blank control group were intraperitoneally injected with normal saline, while those in the other four groups with cyclophosphamide at 50 mg/kg/d, all for 7 days. After modeling, the mice in the blank and model control groups were given distilled water via gavage once a day, and those in the low-, medium- and high-dose BHR groups treated intragastrically with BHR at 7.5, 15 and 30 g/kg/d qd for 30 successive days. Then, the apoptosis index of the testicular spermatogenic cells was obtained by TUNEL and the expressions of Bax and Bcl-2 mRNA and proteins determined by RT-PCR and Western blot, respectively. RESULTS: Compared with the mice in the blank control group, the BHR model controls showed dramatically increased apoptosis of testicular spermatogenic cells and up-regulated mRNA and protein expressions of Bax and Bcl-2 in the testis tissue (P < 0.01). In comparison with the model controls, the mice in the BHR treatment groups exhibited significantly reduced apoptosis of testicular spermatogenic cells and down-regulated mRNA and protein expressions of Bax and Bcl-2 in the testis tissue (P < 0.01). CONCLUSIONS: Bushen Huoxue Recipe can reduce cyclophosphamide-induced apoptosis of testicular spermatogenic cells in mice, which may be associated with its ability of regulating the expressions of Bax and Bcl-2 mRNA and proteins in the testis tissue.


Subject(s)
Apoptosis , Drugs, Chinese Herbal/pharmacology , Testis/drug effects , Animals , Cyclophosphamide/toxicity , Male , Mice , Mice, Inbred BALB C , Random Allocation , Testis/pathology
15.
J Am Chem Soc ; 142(50): 20924-20929, 2020 12 16.
Article in English | MEDLINE | ID: mdl-33238105

ABSTRACT

We have developed a protocol for insertion of alkylidene carbenes into the B-H bonds of amine-borane adducts, enabling, for the first time, the construction of C(sp2)-B bonds by means of carbene-insertion reactions. Various acyclic and cyclic alkenyl borane-amine adducts were prepared from readily accessible starting materials in good to high yields and were subsequently subjected to a diverse array of functional group transformations. The unprecedented spiro B-N heterocycles prepared in this study have potential utility as building blocks for the synthesis of pharmaceuticals. Preliminary mechanistic studies suggest that insertion of the alkylidene carbenes into the B-H bonds of the amine-borane adducts proceeds via a concerted process involving a three-membered-ring transition state.

16.
J Am Chem Soc ; 142(23): 10557-10566, 2020 06 10.
Article in English | MEDLINE | ID: mdl-32406233

ABSTRACT

Catalytic asymmetric reactions in which water is a substrate are rare. Enantioselective transition-metal-catalyzed insertion of carbenes into the O-H bond of water can be used to incorporate water into the stereogenic center, but the reported chiral catalysts give good results only when α-aryl-α-diazoesters are used as the carbene precursors. Herein we report the first highly enantioselective O-H bond insertion reactions between water and α-alkyl- and α-alkenyl-α-diazoesters as carbene precursors, with catalysis by a combination of achiral dirhodium complexes and chiral phosphoric acids or chiral phosphoramides. Participation of the phosphoric acids or phosphoramides in the carbene transfer reaction markedly suppressed competing side reactions, such as ß-H migration, carbene dimerization, and olefin isomerization, and thus ensured good yields of the desired products. Fine-tuning of the ester moiety facilitated enantiocontrol of the proton transfer reactions of the enol intermediates and resulted in excellent enantioselectivity. This protocol represents an efficient new method for preparation of multifunctionalized chiral α-alkyl and α-alkenyl hydroxyl esters, which readily undergo various transformations and can thus be used for the synthesis of bioactive compounds. Mechanistic studies revealed that the phosphoric acids and phosphoramides promoted highly enantioselective [1,2]- and [1,3]-proton transfer reactions of the enol intermediates. Maximization of molecular orbital overlap in the transition states of the proton transfer reactions was the original driving force to involve the proton shuttle catalysts in this process.

17.
J Invertebr Pathol ; 171: 107334, 2020 03.
Article in English | MEDLINE | ID: mdl-32006551

ABSTRACT

FK506 binding proteins (FKBPs) participate in regulation of diverse biological processes. However, the role of these proteins in insect-pathogenic fungi is far from well understood. To investigate the functions of FKBPs in Beauveria bassiana, a widely used entomopathogenic fungus for control of insect pests, we identify three putative FKBP genes, Bbfkbp12, Bbfkbp15, and Bbfkbp50, in the fungus. Gene-disruption experiments show that loss of Bbfkbp12 results in a significant increase of resistance of B. bassiana against the immunosuppressive compounds FK506 and rapamycin, while loss of Bbfkbp50 leads to the resistance to the ergosterol synthesis inhibitor lovastatin. Transcription assays of calcineurin (CaN)- and mTOR (mammalian target of rapamycin)-downstream target genes confirm that BbFKBP12 is the target of both FK506 and rapamycin, associated with CaN- and mTOR-signal pathways in B. bassiana. GFP-tagging of the proteins shows that BbFKBP12 and BbFKBP15 localize in cytoplasm while BbFKBP50 in nucleus. Our results provide useful information for the study of functions of CaN- and mTOR-mediated signaling, and ergosterol synthesis in the entomopathogenic fungi.


Subject(s)
Beauveria/growth & development , Ergosterol/biosynthesis , Fungal Proteins/genetics , Signal Transduction , Tacrolimus Binding Proteins/genetics , Antifungal Agents/metabolism , Beauveria/metabolism , Fungal Proteins/metabolism , Lovastatin/metabolism , Sirolimus/metabolism , Tacrolimus/metabolism , Tacrolimus Binding Proteins/metabolism
18.
Carbohydr Res ; 351: 126-9, 2012 Apr 01.
Article in English | MEDLINE | ID: mdl-22341917

ABSTRACT

A formal synthesis of Jaspine B was completed in 42.4% overall yield with only three purification steps (one by crystallization and two by column chromatography). The key step in the synthesis involves a regio- and stereoselective epoxide ring-opening reaction and the configuration inversion of the C3-hydroxyl group through oxidation and reduction. All of the reagents and materials used were quite common and inexpensive.


Subject(s)
Chemistry Techniques, Synthetic/methods , Sphingosine/analogs & derivatives , Xylose/chemistry , Crystallization , Sphingosine/chemical synthesis
19.
Ying Yong Sheng Tai Xue Bao ; 19(2): 245-51, 2008 Feb.
Article in Chinese | MEDLINE | ID: mdl-18464626

ABSTRACT

By using litterbag method, the decomposition processes of 9 types of foliar litter in secondary conifer and broadleaf mixed forest in Changbai Mountains were assessed during a period of 34 months. The initial N and P concentrations varied greatly among the litters, and there were significant relationships between litter decomposition constant (k) and initial N concentration and C/N. The percent organic matter remaining had a significant linear correlation with percent C remaining, and a significant polynomial correlation with percent N and P remaining. The percent N and P remaining increased with the decomposition of organic matter in its initial decomposition phase, but decreased gradually in the latter decomposition phase. C/N and C/P declined with the decrease of percent organic matter remaining, and the differences in C/N or C/P among litter types decreased, being approached to 23 and 350, respectively by the end of the study. During organic matter decomposition, N/P did not change greatly, and the differences in N/P between litter types declined when the percent organic matter remaining was below 25%. Our study showed that percent of C, N and P mass remaining can be predicted by percent of organic matter mass remaining.


Subject(s)
Carbon/metabolism , Plant Leaves/chemistry , Soil/analysis , Tracheophyta/chemistry , Trees/chemistry , Altitude , China , Ecosystem , Nitrogen/metabolism , Organic Chemicals/metabolism , Phosphorus/metabolism , Plant Leaves/growth & development , Tracheophyta/growth & development , Trees/growth & development
20.
Ying Yong Sheng Tai Xue Bao ; 19(12): 2769-73, 2008 Dec.
Article in Chinese | MEDLINE | ID: mdl-19288737

ABSTRACT

A simulation test was conducted to study the change trends of soil cellulase, polyphenol oxidase, and sucrase activities under natural broadleaf-Korean pine (Pinus koraiensis) and secondary poplar (Populus davidiana) -birch (Betula platyphylla) mixed forests as affected by 0, 25, and 50 kg x hm(-2) x a(-1) of N deposition. The results showed that the effects of elevated N deposition on test enzyme activities varied with forest type, and short-term nitrogen addition could significantly affect the test enzyme activities. High N deposition decreased soil polyphyneol oxidase activity, and correspondingly, soil cellulase and sucrase activities also had a trend of decrease.


Subject(s)
Nitrogen/analysis , Pinus/growth & development , Populus/growth & development , Rain , Soil/analysis , Cellulase/metabolism , Oxidoreductases/metabolism , Sucrase/metabolism
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