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1.
Proc Natl Acad Sci U S A ; 121(39): e2403222121, 2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39302967

RESUMO

Algae mostly occur either as unicellular (microalgae) or multicellular (macroalgae) species, both being uninucleate. There are important exceptions, however, as some unicellular algae are multinucleate and macroscopic, some of which inhabit tropical seas and contribute to biocalcification and coral reef robustness. The evolutionary mechanisms and ecological significance of multinucleation and associated traits (e.g., rapid wound healing) are poorly understood. Here, we report the genome of Halimeda opuntia, a giant multinucleate unicellular chlorophyte characterized by interutricular calcification. We achieve a high-quality genome assembly that shows segregation into four subgenomes, with evidence for polyploidization concomitant with historical sea level and climate changes. We further find myosin VIII missing in H. opuntia and three other unicellular multinucleate chlorophytes, suggesting a potential mechanism that may underpin multinucleation. Genome analysis provides clues about how the unicellular alga could survive fragmentation and regenerate, as well as potential signatures for extracellular calcification and the coupling of calcification with photosynthesis. In addition, proteomic alkalinity shifts were found to potentially confer plasticity of H. opuntia to ocean acidification (OA). Our study provides crucial genetic information necessary for understanding multinucleation, cell regeneration, plasticity to OA, and different modes of calcification in algae and other organisms, which has important implications in reef conservation and bioengineering.


Assuntos
Calcificação Fisiológica , Calcificação Fisiológica/genética , Clorófitas/genética , Clorófitas/metabolismo , Filogenia , Genoma de Planta , Fotossíntese/genética
2.
J Org Chem ; 89(3): 1967-1979, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38241611

RESUMO

Herein, we describe an effective method for the synthesis of 2-alkoxyamides and 1,2-diamines through visible-light-mediated difunctionalization of alkenes. N-Aminopyridinium salts were employed as appropriate precursors to generate key amidyl radical intermediates via a photoinduced single-electron transfer (SET) process. The amidyl radicals would react with alkenes, followed by oxidation and nucleophilic addition. Excellent functional group tolerance and good yields demonstrate the synthetic potential of this transformation.

3.
J Org Chem ; 89(16): 11446-11454, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39113180

RESUMO

An enzyme catalyzed strategy for the synthesis of a chiral hydrazine from 3-cyclopentyl-3-oxopropanenitrile 5 and hydrazine hydrate 2 is presented. An imine reductase (IRED) from Streptosporangium roseum was identified to catalyze the reaction between 3-cyclopentyl-3-oxopropanenitrile 5 and hydrazine hydrate 2 to produce trace amounts of (R)-3-cyclopentyl-3-hydrazineylpropanenitrile 4. We employed a 2-fold approach to optimize the catalytic performance of this enzyme. First, a transition state analogue (TSA) model was constructed to illuminate the enzyme-substrate interactions. Subsequently, the Enzyme_design and Funclib methods were utilized to predict mutants for experimental evaluation. Through three rounds of site-directed mutagenesis, site saturation mutagenesis, and combinatorial mutagenesis, we obtained mutant M6 with a yield of 98% and an enantiomeric excess (ee) of 99%. This study presents an effective method for constructing a hydrazine derivative via IRED-catalyzed reductive amination of ketone and hydrazine. Furthermore, it provides a general approach for constructing suitable enzymes, starting from nonreactive enzymes and gradually enhancing their catalytic activity through active site modifications.


Assuntos
Biocatálise , Nitrilas , Oxirredutases , Pirazóis , Pirimidinas , Nitrilas/química , Nitrilas/metabolismo , Pirimidinas/química , Pirimidinas/biossíntese , Pirimidinas/metabolismo , Oxirredutases/metabolismo , Oxirredutases/genética , Pirazóis/química , Pirazóis/metabolismo , Iminas/química , Iminas/metabolismo , Estrutura Molecular , Hidrazinas/química , Engenharia de Proteínas
4.
Pestic Biochem Physiol ; 195: 105558, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37666594

RESUMO

The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is an extremely destructive notifiable quarantine pest. Over the last two decades, neonicotinoid insecticides, particularly thiamethoxam and imidacloprid, have been used to control it in Xinjiang, and local field populations have developed different levels of resistance in consequence. However, the contributions of nicotinic acetylcholine receptors (nAChRs) to neonicotinoid resistance are currently poorly understood in CPB. Previous studies have shown that nAChRα1, α3, α8 and ß1 are major target subunits for neonicotinoids in some model and important agricultural insects including nAChRα1 subunit of L. decemlineata (Ldα1). In this study, the expression levels of Ldα3, Ldα8 and Ldß1 following 72 h of treatments with median lethal doses of thiamethoxam and imidacloprid were compared using real-time quantitative PCR. These genes were then individually and simultaneously knocked down with Ldα1 by RNA interference (RNAi) using a double-stranded RNA (dsRNA) feeding method for six days to explore their roles in CPB susceptibility to imidacloprid and thiamethoxam. The results showed that the expressions of Ldα3, Ldα8 and Ldß1 were significantly decreased by 36.99-74.89% after thiamethoxam and imidacloprid treatments, compared with the control. The significant downregulation of the target genes resulting from RNAi significantly reduced the mortality of adults exposed to thiamethoxam and imidacloprid by 34.53% -56.44% and 28.78%-43.93%, respectively. Furthermore, the adult survival rates were not affected by every dsRNA-feeding treatment, while the body weight of the test adults significantly deceased after four and six days of individual gene RNAi. This study showed that Ldα3, Ldα8 and Ldß1 are down-regulated by thiamethoxam and imidacloprid and play important roles in the tolerance of CPB to neonicotinoids.


Assuntos
Besouros , Solanum tuberosum , Animais , Besouros/genética , Tiametoxam , Neonicotinoides/farmacologia
5.
Int J Mol Sci ; 24(4)2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36835006

RESUMO

Scutellaria baicalensis is often used to treat breast cancer, but the molecular mechanism behind the action is unclear. In this study, network pharmacology, molecular docking, and molecular dynamics simulation are combined to reveal the most active compound in Scutellaria baicalensis and to explore the interaction between the compound molecule and the target protein in the treatment of breast cancer. In total, 25 active compounds and 91 targets were screened out, mainly enriched in lipids in atherosclerosis, the AGE-RAGE signal pathway of diabetes complications, human cytomegalovirus infection, Kaposi-sarcoma-associated herpesvirus infection, the IL-17 signaling pathway, small-cell lung cancer, measles, proteoglycans in cancer, human immunodeficiency virus 1 infection, and hepatitis B. Molecular docking shows that the two most active compounds, i.e., stigmasterol and coptisine, could bind well to the target AKT1. According to the MD simulations, the coptisine-AKT1 complex shows higher conformational stability and lower interaction energy than the stigmasterol-AKT1 complex. On the one hand, our study demonstrates that Scutellaria baicalensis has the characteristics of multicomponent and multitarget synergistic effects in the treatment of breast cancer. On the other hand, we suggest that the best effective compound is coptisine targeting AKT1, which can provide a theoretical basis for the further study of the drug-like active compounds and offer molecular mechanisms behind their roles in the treatment of breast cancer.


Assuntos
Neoplasias da Mama , Medicamentos de Ervas Chinesas , Neoplasias , Scutellaria baicalensis , Humanos , Medicamentos de Ervas Chinesas/farmacologia , Medicamentos de Ervas Chinesas/uso terapêutico , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Farmacologia em Rede , Estigmasterol/química , Estigmasterol/farmacologia , Neoplasias da Mama/tratamento farmacológico
6.
Mol Biol Evol ; 38(4): 1595-1607, 2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33331879

RESUMO

Sturgeons and paddlefishes (Acipenseriformes) occupy the basal position of ray-finned fishes, although they have cartilaginous skeletons as in Chondrichthyes. This evolutionary status and their morphological specializations make them a research focus, but their complex genomes (polyploidy and the presence of microchromosomes) bring obstacles and challenges to molecular studies. Here, we generated the first high-quality genome assembly of the American paddlefish (Polyodon spathula) at a chromosome level. Comparative genomic analyses revealed a recent species-specific whole-genome duplication event, and extensive chromosomal changes, including head-to-head fusions of pairs of intact, large ancestral chromosomes within the paddlefish. We also provide an overview of the paddlefish SCPP (secretory calcium-binding phosphoprotein) repertoire that is responsible for tissue mineralization, demonstrating that the earliest flourishing of SCPP members occurred at least before the split between Acipenseriformes and teleosts. In summary, this genome assembly provides a genetic resource for understanding chromosomal evolution in polyploid nonteleost fishes and bone mineralization in early vertebrates.


Assuntos
Evolução Biológica , Calcificação Fisiológica/genética , Cromossomos , Peixes/genética , Genoma , Animais , Proteínas de Ligação ao Cálcio/genética , Genes Homeobox , Fosfoproteínas/genética
7.
Planta ; 256(1): 16, 2022 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-35737139

RESUMO

MAIN CONCLUSION: Extensive histology of pistillate flowers revealed two pollen tube arresting sites (the style-joining and micropyle) within the pistil of Quercus acutissima during the postpollination-prezygotic stage, which reflects a unique female and male gametophyte recognition/selection mechanism. Sexual reproduction is among the most delicate and essential stages in plant life cycles and involves a series of precise interactions between pistils and male gametophytes. Quercus is a woody genus that dominates Northern Hemisphere forests and is notorious for interspecific hybridization, but its sexual reproduction is poorly understood, especially its pollen tube (PT) growth dynamics within pistils. This study used microtome techniques and scanning electron microscopy to observe the postpollination-prezygotic process in the biennially fruiting oak Quercus acutissima. Many pollen grains germinated at anthesis instantly, and PTs penetrated stigmatic surfaces and elongated through the stylar transmitting tissue, then arrested at style-joining for about 12-13 months. Few PTs resumed growth along the compitum in the upper ovarian locule wall in the subsequent April, concurrent with the rapid growth of rudimentary ovules. PTs arrived in the micropyle, and upper septum during megaspore mother cell meiosis, then arrested again for 7-10 days waiting for the embryo sac maturation. Fertilization occurred one week later. Our study shows a clear female dominant crosstalk growth pattern between PT and the ovule. The intermittent PT growth might reflect a unique male gametophyte recognition/selection mechanism to avoid self-pollination and enhance PT competition while increasing interspecific hybridization.


Assuntos
Tubo Polínico , Quercus , Flores , Polinização , Reprodução
8.
Br J Clin Pharmacol ; 88(10): 4505-4514, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35487881

RESUMO

AIMS: To investigate the effects of ABCB1 DNA methylation in donors on individual differences in tacrolimus blood concentrations following liver transplantation. METHODS: Twenty-three donor liver samples carrying the CYP3A5*3/*3 genotype were classified into 2 groups based on their initial tacrolimus blood concentrations (C0  >10 µg/L or <5 µg/L) following liver transplantation. ABCB1 mRNA levels in liver tissues and HepG2 cells were determined by quantitative reverse transcriptase polymerase chain reaction. DNA methylation status in liver tissues and HepG2 cells was determined using Illumina 850 methylation chip sequencing technology and pyrosequencing. 5-Aza-2dC was used to reverse methylation in HepG2 cells. Intracellular tacrolimus concentrations were determined by liquid mass spectrometry. RESULTS: Genome-wide methylation sequencing and pyrosequencing analyses showed that the methylation levels of 3 ABCB1 CpG sites (cg12501229, cg00634941 and cg05496710) were significantly different between groups with different tacrolimus concentration/dose (C0 /D) ratios. ABCB1 mRNA expression in donor livers was found to be positively correlated with tacrolimus C0 /D ratio (R = .458, P < .05). After treatment with 5-Aza-2-Dc, the methylation levels of the ABCB1 CpG sites in HepG2 cells significantly decreased, and this was confirmed by pyrosequencing; there was also a significant increase in ABCB1 transcription, which induced a decrease in intracellular tacrolimus concentrations. CONCLUSION: ABCB1 CpG site methylation affects tacrolimus metabolism in humans by regulating ABCB1 expression. Therefore, ABCB1 DNA methylation in donor livers might be an important epigenetic factor that affects tacrolimus blood concentrations following liver transplantation.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Imunossupressores , Transplante de Fígado , Tacrolimo , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Citocromo P-450 CYP3A/genética , Metilação de DNA , Genótipo , Humanos , Imunossupressores/sangue , Doadores Vivos , Polimorfismo de Nucleotídeo Único , RNA Mensageiro , Tacrolimo/sangue
9.
J Transl Med ; 19(1): 5, 2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33407585

RESUMO

BACKGROUND: The tumor immunological microenvironment (TIME) has a prominent impact on prognosis and immunotherapy. However, the heterogeneous TIME and the mechanisms by which TIME affects immunotherapy have not been elucidated in hepatocellular carcinoma (HCC). METHODS: A total of 2195 eligible HCC patients from TCGA and GEO database were collected. We comprehensively explored the different heterogeneous TIME phenotypes and its clinical significance. The potential immune escape mechanisms and what genomic alterations may drive the formation of different phenotypes were further investigated. RESULTS: We identified three phenotypes in HCC: TIME-1, the "immune-deficiency" phenotype, with immune cell depletion and proliferation; TIME-2, the "immune-suppressed" phenotype, with enrichment of immunosuppressive cells; TIME-3, the "immune-activated phenotype", with abundant leukocytes infiltration and immune activation. The prognosis and sensitivity to both sorafenib and immunotherapy differed among the three phenotypes. We also underlined the potential immune escape mechanisms: lack of leukocytes and defective tumor antigen presentation capacity in TIME-1, increased immunosuppressive cells in TIME-2, and rich in immunoinhibitory molecules in TIME-3. The different phenotypes also demonstrated specific genomic events: TIME-1 characterized by TP53, CDKN2A, CTNNB1, AXIN1 and FOXD4 alterations; TIME-2 characterized by significant alteration patterns in the PI3K pathway; TIME-3 characterized by ARID1A mutation. Besides, the TIME index (TI) was proposed to quantify TIME infiltration pattern, and it was a superior prognostic and immunotherapy predictor. A pipeline was developed to classify single patient into one of these three subtypes and calculated the TI. CONCLUSIONS: We identified three TIME phenotypes with different clinical outcomes, immune escape mechanisms and genomic alterations in HCC, which could present strategies for improving the efficacy of immunotherapy. TI as a novel prognostic and immunotherapeutic signature that could guide personalized immunotherapy and clinical management of HCC.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/terapia , Genômica , Humanos , Imunoterapia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/terapia , Fosfatidilinositol 3-Quinases , Microambiente Tumoral
10.
Angew Chem Int Ed Engl ; 59(11): 4478-4483, 2020 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-31829494

RESUMO

A continuous, scalable, and solvent-free method for the synthesis of various naphthalic imides and perylene diimides (PDIs) using twin-screw extrusion (TSE) is reported. Using TSE, naphthalic imides were obtained quantitatively without the need for excess amine reactant or product purification. With good functional-group tolerance, alkyl and benzyl amine derived PDIs (incl. commercial dyes) were obtained in 50-99 % yield. Use of K2 CO3 , enabled synthesis of more difficult aniline-derived PDIs. Furthermore, an automated continuous TSE process for Pigments Black 31 and 32 is demonstrated, with a throughput rate of about 1500 g day-1 , corresponding to a space time yield of about 30×103  kg m-3  day-1 , which is 1-2 orders of magnitude greater than for solvent-based batch methods. These methods provide substantial waste reductions and improved efficiency compared to conventional solvent-based methods.

11.
Plant J ; 92(3): 452-468, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28849613

RESUMO

Allotetraploid oilseed rape (Brassica napus L.) is an agriculturally important crop. Cultivation and breeding of B. napus by humans has resulted in numerous genetically diverse morphotypes with optimized agronomic traits and ecophysiological adaptation. To further understand the genetic basis of diversification and adaptation, we report a draft genome of an Asian semi-winter oilseed rape cultivar 'ZS11' and its comprehensive genomic comparison with the genomes of the winter-type cultivar 'Darmor-bzh' as well as two progenitors. The integrated BAC-to-BAC and whole-genome shotgun sequencing strategies were effective in the assembly of repetitive regions (especially young long terminal repeats) and resulted in a high-quality genome assembly of B. napus 'ZS11'. Within a short evolutionary period (~6700 years ago), semi-winter-type 'ZS11' and the winter-type 'Darmor-bzh' maintained highly genomic collinearity. Even so, certain genetic differences were also detected in two morphotypes. Relative to 'Darmor-bzh', both two subgenomes of 'ZS11' are closely related to its progenitors, and the 'ZS11' genome harbored several specific segmental homoeologous exchanges (HEs). Furthermore, the semi-winter-type 'ZS11' underwent potential genomic introgressions with B. rapa (Ar ). Some of these genetic differences were associated with key agronomic traits. A key gene of A03.FLC3 regulating vernalization-responsive flowering time in 'ZS11' was first experienced HE, and then underwent genomic introgression event with Ar , which potentially has led to genetic differences in controlling vernalization in the semi-winter types. Our observations improved our understanding of the genetic diversity of different B. napus morphotypes and the cultivation history of semi-winter oilseed rape in Asia.


Assuntos
Brassica napus/genética , Brassica/genética , Variação Genética , Genoma de Planta/genética , Genômica , Sequência de Aminoácidos , Evolução Biológica , Cruzamento , Sequenciamento de Nucleotídeos em Larga Escala , Fenótipo , Poliploidia , Alinhamento de Sequência , Análise de Sequência de DNA
12.
J Org Chem ; 83(17): 9696-9706, 2018 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-30067027

RESUMO

Here we describe a straightforward and efficient approach for regiospecific introduction of an allyl group into cycloalkanol molecules employing a visible-light-mediated ring-opening strategy. A wide range of distally allylated or formylated ketones is furnished from 1-aryl cycloalkanol precursors of variable ring sizes, providing a concise and practical access for the modification of complex natural products. Preliminary mechanistic studies demonstrate that the key O-centered radicals mediate the sequential ring cleavage and allylation/formylation.

13.
Exp Cell Res ; 358(2): 234-241, 2017 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-28663057

RESUMO

Neddylation inhibitor Pevonedistat (MLN4924) is a novel anticancer drug and has demonstrated broad-spectrum anticancer activity. Nevertheless, we found that Pevonedistat had only a modest apoptotic effect in osteosarcoma (OS) cells. Moreover, we noted that inhibition of neddylation by Pevonedistat led to accumulation of Mcl-1 protein in OS cells. Because Mcl-1 is an important anti-apoptotic protein and also because apoptosis has been shown to be a major cell death pathway, we hypothesized that Mcl-1 accumulation negatively impacted Pevonedistat-mediated anticancer activity in OS cells. In this regard, we employed genetic or pharmacological approaches to inhibit Mcl-1 expression and to examine the effect on Pevonedistat-induced apoptosis in OS cells. We found that inhibition of Mcl-1 expression by siRNA considerably enhanced Pevonedistat-triggered the activation of caspase-3, PARP cleavage and apoptosis, and also dramatically promoted the ability of Pevonedistat to inhibit colony formation of OS cells. Moreover, we observed that flavopiridol, a FDA approved drug, inhibited Mcl-1 expression and substantially enhanced Pevonedistat-mediated activation of apoptosis signaling and significantly augmented cell killing effect in OS cells. Altogether, our study shows that Mcl-1 is a critical resistance factor to Pevonedistat monotherapy, and suggests that Pevonedistat in combinations with flavopiridol may achieve better anticancer therapy.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Ciclopentanos/farmacologia , Osteossarcoma/metabolismo , Pirimidinas/farmacologia , Caspase 3/metabolismo , Linhagem Celular Tumoral/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo
14.
Mol Carcinog ; 55(5): 910-7, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-25969347

RESUMO

Arsenic exposure has been reported to cause neoplastic transformation through the activation of PcG proteins. In the present study, we show that activation of p38α mitogen-activated protein kinase (MAPK) is required for arsenic-induced neoplastic transformation. Exposure of cells to 0.5 µM arsenic increased CRE and c-Fos promoter activities that were accompanied by increases in p38α MAPK and CREB phosphorylation and expression levels concurrently with AP-1 activation. Introduction of short hairpin (sh) RNA-p38α into BALB/c 3T3 cells markedly suppressed arsenic-induced colony formation compared with wildtype cells. CREB phosphorylation and AP-1 activation were decreased in p38α knockdown cells after arsenic treatment. Arsenic-induced AP-1 activation, measured as c-Fos and CRE promoter activities, and CREB phosphorylation were attenuated by p38 inhibition in BALB/c 3T3 cells. Thus, p38α MAPK activation is required for arsenic-induced neoplastic transformation mediated through CREB phosphorylation and AP-1 activation.


Assuntos
Arsênio/toxicidade , Transformação Celular Neoplásica/induzido quimicamente , Transformação Celular Neoplásica/metabolismo , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Animais , Células 3T3 BALB , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Camundongos , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Fator de Transcrição AP-1/metabolismo
15.
Plant Cell ; 25(8): 2813-30, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23983221

RESUMO

The Brassicaceae, including Arabidopsis thaliana and Brassica crops, is unmatched among plants in its wealth of genomic and functional molecular data and has long served as a model for understanding gene, genome, and trait evolution. However, genome information from a phylogenetic outgroup that is essential for inferring directionality of evolutionary change has been lacking. We therefore sequenced the genome of the spider flower (Tarenaya hassleriana) from the Brassicaceae sister family, the Cleomaceae. By comparative analysis of the two lineages, we show that genome evolution following ancient polyploidy and gene duplication events affect reproductively important traits. We found an ancient genome triplication in Tarenaya (Th-α) that is independent of the Brassicaceae-specific duplication (At-α) and nested Brassica (Br-α) triplication. To showcase the potential of sister lineage genome analysis, we investigated the state of floral developmental genes and show Brassica retains twice as many floral MADS (for minichromosome maintenance1, AGAMOUS, DEFICIENS and serum response factor) genes as Tarenaya that likely contribute to morphological diversity in Brassica. We also performed synteny analysis of gene families that confer self-incompatibility in Brassicaceae and found that the critical serine receptor kinase receptor gene is derived from a lineage-specific tandem duplication. The T. hassleriana genome will facilitate future research toward elucidating the evolutionary history of Brassicaceae genomes.


Assuntos
Brassicaceae/genética , Evolução Molecular , Genoma de Planta/genética , Característica Quantitativa Herdável , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Proteínas de Domínio MADS/genética , Proteínas de Domínio MADS/metabolismo , Anotação de Sequência Molecular , Filogenia , Mapeamento Físico do Cromossomo , Poliploidia , Reprodução/genética , Autoincompatibilidade em Angiospermas/genética , Análise de Sequência de DNA , Sintenia/genética , Fatores de Tempo
16.
Plant J ; 76(4): 557-67, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23952714

RESUMO

Sacred lotus (Nelumbo nucifera) is an ornamental plant that is also used for food and medicine. This basal eudicot species is especially important from an evolutionary perspective, as it occupies a critical phylogenetic position in flowering plants. Here we report the draft genome of a wild strain of sacred lotus. The assembled genome is 792 Mb, which is approximately 85-90% of genome size estimates. We annotated 392 Mb of repeat sequences and 36,385 protein-coding genes within the genome. Using these sequence data, we constructed a phylogenetic tree and confirmed the basal location of sacred lotus within eudicots. Importantly, we found evidence for a relatively recent whole-genome duplication event; any indication of the ancient paleo-hexaploid event was, however, absent. Genomic analysis revealed evidence of positive selection within 28 embryo-defective genes and one annexin gene that may be related to the long-term viability of sacred lotus seed. We also identified a significant expansion of starch synthase genes, which probably elevated starch levels within the rhizome of sacred lotus. Sequencing this strain of sacred lotus thus provided important insights into the evolution of flowering plant and revealed genetic mechanisms that influence seed dormancy and starch synthesis.


Assuntos
Evolução Biológica , Genoma de Planta , Nelumbo/genética , Sequência de Aminoácidos , Dados de Sequência Molecular , Nelumbo/crescimento & desenvolvimento , Dormência de Plantas/genética , Sementes/crescimento & desenvolvimento , Seleção Genética , Análise de Sequência de DNA , Amido/biossíntese
17.
Materials (Basel) ; 17(11)2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38893864

RESUMO

A solid-state repair technique based on surface friction welding is investigated in depth to achieve excellent mechanical properties of damaged 7A52 aluminum alloy. The results show that the yield strength and tensile strength along the repair direction are 436 MPa and 502 MPa, respectively, at a rotational speed of 1400 rpm and a travel speed of 300 mm/min, which are about 157.9% and 129.7% of those before the defects were repaired, respectively, while the elongation is 17.2% compared to the base material. Perpendicular to the repair direction, the yield strength and tensile strength are 254 MPa and 432 MPa, which are 111.4% and 129.7% of those before the defects were repaired, respectively, while the elongation is 11.8% compared to the base material. The mechanical properties of the repaired areas are still improved compared to those of the defect-free sheets. On the one hand, this is attributed to the dynamic recrystallization of the nugget zone due to the thermo-mechanical coupling, resulting in the formation of a fine, equiaxed grain structure; on the other hand, the precipitated Mg2Si phase, which is incoherent within the base material, transforms into the Al12(Fe, Mn)3Si phase, as well as the precipitation of the Al6Mn phase and η' phase, resulting in the enhancement of the properties. The material fracture at the junction of the nugget zone and the heat-affected zone occurs after repair, which is attributed to the significant difference in the texture of the nugget zone and the heat-affected zone, as well as to the stress concentration at the junction.

18.
Materials (Basel) ; 17(11)2024 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-38893896

RESUMO

This research investigated the relationship between volume energy density and the microstructure, density, and mechanical properties of the Ti-5Al-5Mo-3V-1Cr-1Fe alloy fabricated via the SLM process. The results indicate that an increase in volume energy density can promote a transition from a columnar to an equiaxed grain structure and suppress the anisotropy of mechanical properties. Specifically, at a volume energy density of 83.33 J/mm3, the average aspect ratio of ß grains reached 0.77, accompanied by the formation of numerous nano-precipitated phases. Furthermore, the relative density of the alloy initially increased and then decreased as the volume energy density increased. At a volume energy density of 83.33 J/mm3, the relative density reached 99.6%. It is noteworthy that an increase in volume energy density increases the ß grain size. Consequently, with a volume energy density of 83.33 J/mm3, the alloy exhibited an average grain size of 63.92 µm, demonstrating optimal performance with a yield strength of 1003.06 MPa and an elongation of 18.16%. This is mainly attributable to the fact that an increase in volume energy density enhances thermal convection within the molten pool, leading to alterations in molten pool morphology and a reduction in temperature gradients within the alloy. The reduction in temperature gradients promotes equiaxed grain transformation and grain refinement by increasing constitutive supercooling at the leading edge of the solid-liquid interface. The evolution of molten pool morphology mainly inhibits columnar grain growth and refines grain by changing the grain growth direction. This study provided a straightforward method for inhibiting anisotropy and enhancing mechanical properties.

19.
Front Microbiol ; 15: 1448629, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39372270

RESUMO

Background: Multiple studies suggest a potential connection between the gut microbiome and asthma. Our objective is to use advanced genetic and metagenomic techniques to elucidate the causal relationships and underlying mechanisms between gut microbiota and asthma. Methods: The study utilized comprehensive Linkage Disequilibrium Score Regression (LDSC) and Mendelian randomization (MR) analyses to examine the relationship between 119 gut microbiota genera and asthma, using publicly accessible genome-wide association studies (GWAS). The meta-analysis synthesized summary effect estimates obtained from LDSC, forward MR, and reverse MR. The MiBioGen collaboration, involving 18,340 individuals, identified genetic variations associated with gut bacteria. Asthma data were collected from the UK Biobank, FinnGen, and GERA, encompassing a total of 82,060 cases and 641,049 controls. Results: LDSC analysis revealed significant negative genetic correlations between asthma and RuminococcaceaeUCG004 (Rg = -0.55, p = 7.66 × 10-5) and Subdoligranulum (Rg = -0.35, p = 3.61 × 10-4). Forward MR analysis suggested associations between Butyricicoccus (OR = 0.92, p = 0.01), Turicibacter (OR = 0.95, p = 0.025), Butyrivibrio (OR = 0.98, p = 0.047), and reduced asthma risk. Conversely, Coprococcus2 (OR = 1.10, p = 0.035) and Roseburia (OR = 1.07, p = 0.039) were associated with increased risk. Reverse MR analysis indicated significant associations between genetically predicted asthma and Eubacteriumxylanophilumgroup (Beta = -0.08, p = 9.25 × 10-7), LachnospiraceaeNK4A136group (Beta = -0.05, p = 1.26 × 10-4), and Eisenbergiella (Beta = 0.06, p = 0.015, Rg_P = 0.043). Conclusion: The findings underscore significant genetic correlations and causal relationships between specific gut microbiota and asthma. These insights highlight the potential of gut microbiota as both markers and modulators of asthma risk, offering new avenues for targeted therapeutic strategies.

20.
Sci Total Environ ; 954: 176507, 2024 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-39341256

RESUMO

Chlorinated paraffins (CPs) are intricate industrial compounds synthesized through alkane chlorination. Researches on the size distribution of short-chain (SCCPs) and medium-chain chlorinated paraffins (MCCPs) in atmospheric particulate matter (PM) are limited. Here, we conducted a thorough investigation on the size-dependent distribution characteristics, deposition behavior in respiratory tract, and health risks associated with CPs in atmospheric PM. The concentration of SCCPs in atmospheric particulate matter (PM10) was much higher than MCCPs, with concentration ranges of 2.53-31.8 and 1.07-4.62 ng m-3, respectively. Concentrations of CPs increase with decreasing PM size, peaking at aerodynamic diameters (Dp) < 0.49 µm. Physicochemical properties influence the distribution of CP homologs in PM. Those with lower vapor pressure, higher octanol-air and octanol-water partition coefficients tended to accumulate in PM with larger geometric mean diameters. Most of the inhaled CPs in PM deposited in the upper airways, with a small amount in the trachea and alveolar regions. The estimated daily intakes values were highest when Dp < 0.49 µm. Particle size is an essential determinant for the deposition of inhaled CPs in PM and should be considered in health risk assessments.

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