RESUMO
Ghost introgression, or the transfer of genetic material from extinct or unsampled lineages to sampled species, has attracted much attention. However, conclusive evidence for ghost introgression, especially in plant species, remains scarce. Here, we newly assembled chromosome-level genomes for both Carya sinensis and Carya cathayensis, and additionally re-sequenced the whole genomes of 43 C. sinensis individuals as well as 11 individuals representing 11 diploid hickory species. These genomic datasets were used to investigate the reticulation and bifurcation patterns within the genus Carya (Juglandaceae), with a particular focus on the beaked hickory C. sinensis. By combining the D-statistic and BPP methods, we obtained compelling evidence that supports the occurrence of ghost introgression in C. sinensis from an extinct ancestral hickory lineage. This conclusion was reinforced through the phylogenetic network analysis and a genome scan method VolcanoFinder, the latter of which can detect signatures of adaptive introgression from unknown donors. Our results not only dispel certain misconceptions about the phylogenetic history of C. sinensis but also further refine our understanding of Carya's biogeography via divergence estimates. Moreover, the successful integration of the D-statistic and BPP methods demonstrates their efficacy in facilitating a more precise identification of introgression types.
Assuntos
Introgressão Genética , Genoma de Planta , Filogenia , Genoma de Planta/genética , Genômica , Ásia Oriental , População do Leste AsiáticoRESUMO
When challenged by similar environmental conditions, phylogenetically distant taxa often independently evolve similar traits (convergent evolution). Meanwhile, adaptation to extreme habitats might lead to divergence between taxa that are otherwise closely related. These processes have long existed in the conceptual sphere, yet molecular evidence, especially for woody perennials, is scarce. The karst endemic Platycarya longipes, and its only congeneric species, P. strobilacea, which is widely distributed in the mountains in East Asia, provide an ideal model for examining the molecular basis of both convergent evolution and speciation. Using chromosome-level genome assemblies of both species, and whole genome resequencing data from 207 individuals spanning their entire distribution range, we demonstrate that P. longipes and P. strobilacea form two species-specific clades, which diverged around 2.09 million years ago. We find an excess of genomic regions exhibiting extreme interspecific differentiation, potentially due to long-term selection in P. longipes, likely contributing to the incipient speciation of the genus Platycarya. Interestingly, our results unveil underlying karst adaptation in both copies of the calcium influx channel gene TPC1 in P. longipes. TPC1 has previously been identified as a selective target in certain karst-endemic herbs, indicating a convergent adaptation to high calcium stress among karst-endemic species. Our study reveals the genic convergence of TPC1 among karst endemics, and the driving forces underneath the incipient speciation of the two Platycarya lineages.
Assuntos
Carbonato de Cálcio , Juglandaceae , Cálcio , Especiação Genética , GenômicaRESUMO
When challenged by similar environmental conditions, phylogenetically distant taxa often independently evolve similar traits (convergent evolution). Meanwhile, adaptation to extreme habitats might lead to divergence between taxa that are otherwise closely related. These processes have long existed in the conceptual sphere, yet molecular evidence, especially for woody perennials, is scarce. The karst endemic Platycarya longipes and its only congeneric species, Platycarya strobilacea, which is widely distributed in the mountains in East Asia, provide an ideal model for examining the molecular basis of both convergent evolution and speciation. Using chromosome-level genome assemblies of both species, and whole-genome resequencing data from 207 individuals spanning their entire distribution range, we demonstrate that P. longipes and P. strobilacea form two species-specific clades, which diverged around 2.09 million years ago. We find an excess of genomic regions exhibiting extreme interspecific differentiation, potentially due to long-term selection in P. longipes, likely contributing to the incipient speciation of the genus Platycarya. Interestingly, our results unveil underlying karst adaptation in both copies of the calcium influx channel gene TPC1 in P. longipes. TPC1 has previously been identified as a selective target in certain karst-endemic herbs, indicating a convergent adaptation to high calcium stress among karst-endemic species. Our study reveals the genic convergence of TPC1 among karst endemics and the driving forces underneath the incipient speciation of the two Platycarya lineages.
Assuntos
Carbonato de Cálcio , Juglandaceae , Ásia Oriental , Cálcio , Especiação Genética , Genômica , Juglandaceae/genética , Juglandaceae/fisiologiaRESUMO
Fig wasps (Agaonidae; Hymenoptera) are the only pollinating insects of fig trees (Ficus; Moraceae), forming the most closely and highly specific mutualism with the host. We used transcriptome sequences of 25 fig wasps from six genera to explore the evolution of key molecular components of fig wasp chemosensory genes: odorant-binding proteins (OBPs) and chemosensory proteins (CSPs). We identified a total 321 OBPs and 240 CSPs, with each species recording from 6 to 27 OBP genes and 6-19 CSP genes. 318 OBP genes are clustered into 17 orthologous groups and can be divided into two groups: PBP sensitive to pheromone and GOBP sensitive to general odor molecules, such as alcohols, esters, acids, ketones, and terpenoids. 240 CSP genes are clustered into 12 orthologous groups, which can be divided into three major groups and have functions, such as olfactory, tissue formation and/or regeneration, developmental, and some specific and unknown function. The gene sequences of most orthologous groups vary greatly among species and are consistent with the phylogenetic relationships between fig wasps. Strong purifying selection of both OBP and CSP genes was detected, as shown by low ω values. A positive selection was detected in one locus in CSP1. In conclusion, the evolution of chemosensory proteins OBPs and CSPs in fig wasps is relatively conservative, and they play an indispensable role in the life activities of fig wasps. Our results provide a starting point for understanding the molecular basis of the chemosensory systems of fig wasps.
Assuntos
Ficus , Vespas , Animais , Filogenia , Vespas/genética , Ficus/genética , Odorantes , SimbioseRESUMO
Wolbachia is a genus of maternally inherited endosymbionts that can affect reproduction of their hosts and influence metabolic processes. The pollinator, Valisia javana, is common in the male syconium of the dioecious fig Ficus hirta. Based on a high-quality chromosome-level V. javana genome with PacBio long-read and Illumina short-read sequencing, we discovered a sizeable proportion of Wolbachia sequences and used these to assemble two novel Wolbachia strains belonging to supergroup A. We explored its phylogenetic relationship with described Wolbachia strains based on MLST sequences and the possibility of induction of CI (cytoplasmic incompatibility) in this strain by examining the presence of cif genes known to be responsible for CI in other insects. We also identified mobile genetic elements including prophages and insertion sequences, genes related to biotin synthesis and metabolism. A total of two prophages and 256 insertion sequences were found. The prophage WOjav1 is cryptic (structure incomplete) and WOjav2 is relatively intact. IS5 is the dominant transposon family. At least three pairs of type I cif genes with three copies were found which may cause strong CI although this needs experimental verification; we also considered possible nutritional effects of the Wolbachia by identifying genes related to biotin production, absorption and metabolism. This study provides a resource for further studies of Wolbachia-pollinator-host plant interactions.
Assuntos
Ficus , Wolbachia , Ficus/genética , Wolbachia/genética , Biotina/genética , Simbiose/genética , Filogenia , Elementos de DNA Transponíveis/genética , Tipagem de Sequências Multilocus , Prófagos/genética , ReproduçãoRESUMO
Although hybridization plays a large role in speciation, some unknown fraction of hybrid individuals never reproduces, instead remaining as genetic dead-ends. We investigated a morphologically distinct and culturally important Chinese walnut, Juglans hopeiensis, suspected to have arisen from hybridization of Persian walnut (J. regia) with Asian butternuts (J. cathayensis, J. mandshurica, and hybrids between J. cathayensis and J. mandshurica). Based on 151 whole-genome sequences of the relevant taxa, we discovered that all J. hopeiensis individuals are first-generation hybrids, with the time for the onset of gene flow estimated as 370,000 years, implying both strong postzygotic barriers and the presence of J. regia in China by that time. Six inversion regions enriched for genes associated with pollen germination and pollen tube growth may be involved in the postzygotic barriers that prevent sexual reproduction in the hybrids. Despite its long-recurrent origination and distinct traits, J. hopeiensis does not appear on the way to speciation.
Assuntos
Juglans , Fluxo Gênico , Genômica , Humanos , Hibridização Genética , Juglans/genética , ÁrvoresRESUMO
The production of optimized strains of a specific phenotype requires the construction and testing of a large number of genome modifications and combinations thereof. Most bacterial iterative genome-editing methods include essential steps to eliminate selection markers, or to cure plasmids. Additionally, the presence of escapers leads to time-consuming separate single clone picking and subsequent cultivation steps. Herein, we report a genome-editing method based on a Rock-Paper-Scissors (RPS) strategy. Each of three constructed sgRNA plasmids can cure, or be cured by, the other two plasmids in the system; plasmids from a previous round of editing can be cured while the current round of editing takes place. Due to the enhanced curing efficiency and embedded double check mechanism, separate steps for plasmid curing or confirmation are not necessary, and only two times of cultivation are needed per genome-editing round. This method was successfully demonstrated in Escherichia coli and Klebsiella pneumoniae with both gene deletions and replacements. To the best of our knowledge, this is the fastest and most robust iterative genome-editing method, with the least times of cultivation decreasing the possibilities of spontaneous genome mutations.
Assuntos
Resistência Microbiana a Medicamentos/genética , Edição de Genes/métodos , Plasmídeos/genética , RNA Guia de Cinetoplastídeos/genética , Sistemas CRISPR-Cas , Cloranfenicol/farmacologia , Células Clonais , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Técnicas de Inativação de Genes , Genes Bacterianos , Canamicina/farmacologia , Resistência a Canamicina/genética , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/metabolismo , Lactatos/metabolismo , Mutação , Motivos de Nucleotídeos , Regiões Promotoras Genéticas/genética , Ácido Pirúvico/metabolismo , Seleção Genética , Tetraciclina/farmacologia , Resistência a Tetraciclina/genética , Fatores de Tempo , Transformação BacterianaRESUMO
Propionyl-CoA carboxylase (PCC) is a promising enzyme in the fields of biological CO2 utilization, synthesis of natrual products, and so on. The activity and substrate specificity of PCC are dependent on its key subunit carboxyltransferase (CT). To obtain PCC with high enzyme activity, seven pccB genes encoding CT subunit from diverse microorganisms were expressed in recombinant E. coli, and PccB from Bacillus subtilis showed the highest activity in vitro. To further optimize this protein using directed evolution, a genetic screening system based on oxaloacetate availability was designed to enrich the active variants of PccBBs. Four amino acid substitutions (D46G, L97Q, N220I and I391T) proved of great assistance in PccBBs activity improvement, and a double mutant of PccBBs (N220I/I391T) showed a 94-fold increase of overall catalytic efficiency indicated by kcat/Km. Moreover, this PccBBs double mutant was applied in construction of new succinate biosynthetic pathway. This new pathway produces succinate from acetyl-CoA with fixation of two CO2 molecules, which was confirmed by isotope labeling experiment with NaH13CO3. Compared with previous succinate production based on carboxylation of phosphoenolpyruvate or pyruvate, this new pathway showed some advantages including higher CO2 fixation potentiality and availability under aerobic conditions. In summary, this study developed a PCC with high enzyme activity which can be widely used in biotechnology field, and also demonstrated the feasibility of new succinate biosynthetic pathway with two CO2 fixation reactions.
Assuntos
Dióxido de Carbono , Ácido Succínico , Vias Biossintéticas , Escherichia coli/genética , Escherichia coli/metabolismo , Metilmalonil-CoA Descarboxilase/genética , Metilmalonil-CoA Descarboxilase/metabolismo , SuccinatosRESUMO
BACKGROUND: Glycolate is a valuable chemical with extensive applications in many different fields. The traditional methods to synthesize glycolate are quite expensive and toxic. So, the biotechnological production of glycolate from sustainable feedstocks is of interest for its potential economic and environmental advantages. D-Xylose is the second most abundant sugar in nature and accounts for 18-30% of sugar in lignocellulose. New routes for the conversion of xylose to glycolate were explored. RESULTS: Overexpression of aceA and ghrA and deletion of aceB in Escherichia coli were examined for glycolate production from xylose, but the conversion was initially ineffective. Then, a new route for glycolate production was established in E. coli by introducing NAD+-dependent xylose dehydrogenase (xdh) and xylonolactonase (xylC) from Caulobacter crescentus. The constructed engineered strain Q2562 produced 28.82 ± 0.56 g/L glycolate from xylose with 0.60 ± 0.01 g/L/h productivity and 0.38 ± 0.07 g/g xylose yield. However, 27.18 ± 2.13 g/L acetate was accumulated after fermentation. Deletions of iclR and ackA were used to overcome the acetate excretion. An ackA knockout resulted in about 66% decrease in acetate formation. The final engineered strain Q2742 produced 43.60 ± 1.22 g/L glycolate, with 0.91 ± 0.02 g/L/h productivity and 0.46 ± 0.03 g/g xylose yield. CONCLUSIONS: A new route for glycolate production from xylose was established, and an engineered strain Q2742 was constructed from this new explored pathway. The engineering strain showed the highest reported productivity of glycolate to date. This research opened up a new prospect for bio-refinery of xylose and an alternative choice for industrial production of glycolate.
Assuntos
Biotecnologia/métodos , Escherichia coli/química , Glicolatos/química , Engenharia Metabólica/métodos , Xilose/metabolismoRESUMO
BACKGROUND: Acetyl-CoA-derived chemicals are suitable for multiple applications in many industries. The bio-production of these chemicals has become imperative owing to the economic and environmental problems. However, acetate overflow is the major drawback for acetyl-CoA-derived chemicals production. Approaches for overcoming acetate overflow may be beneficial for the production of acetyl-CoA-derived chemicals. RESULTS: In this study, a transcriptional regulator iclR was knocked out in E.coli BL21(DE3) to overcome acetate overflow and improve the chemicals production. Two important acetyl-CoA-derived chemicals, phloroglucinol (PG) and 3-hydroxypropionate (3HP) were used to evaluate it. It is revealed that knockout of iclR significantly increased expressions of aceBAK operon. The cell yields and glucose utilization efficiencies were higher than those of control strains. The acetate concentrations were decreased by more than 50% and the productions of PG and 3HP were increased more than twice in iclR mutants. The effects of iclR knockout on cell physiology, cell metabolism and production of acetyl-CoA-derived chemicals were similar to those of arcA knockout in our previous study. However, the arcA-iclR double mutants couldn't gain higher productions of PG and 3HP. The mechanisms are unclear and needed to be resolved in future. CONCLUSIONS: Knockout of iclR significantly increased gene expression of aceBAK operon and concomitantly activated glyoxylate pathway. This genetic modification may be a good way to overcome acetate overflow, and improve the production of a wide range of acetyl-CoA-derived chemicals.
Assuntos
Acetilcoenzima A/metabolismo , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Proteínas Repressoras/genética , Deleção de Sequência/genética , Acetatos/metabolismo , Acetilcoenzima A/biossíntese , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/fisiologia , Técnicas de Inativação de Genes , Glucose/metabolismo , Glioxilatos/metabolismo , Ácido Láctico/análogos & derivados , Ácido Láctico/metabolismo , Redes e Vias Metabólicas/genética , Óperon , Floroglucinol/metabolismoRESUMO
3-Hydroxypropionate (3HP) is an attractive platform chemical, serving as a precursor to a variety of commodity chemicals like acrylate and acrylamide, as well as a monomer of a biodegradable plastic. To establish a sustainable way to produce these commercially important chemicals and materials, fermentative production of 3HP is widely investigated in recent years. It is reported that 3HP can be produced from several intermediates, such as glycerol, malonyl-CoA, and ß-alanine. Among all these biosynthetic routes, the malonyl-CoA pathway has some distinct advantages, including a broad feedstock spectrum, thermodynamic feasibility, and redox neutrality. To date, this pathway has been successfully constructed in various species including Escherichia coli, yeast and cyanobacteria, and optimized through carbon flux redirection, enzyme screening and engineering, and an increasing supply of energy and cofactors, resulting in significantly enhanced 3HP titer up to 40 g/L. These results show the feasibility of commercial manufacturing of 3HP and its derivatives in the future.
Assuntos
Malonil Coenzima A/metabolismo , Escherichia coli , Ácido Láctico , Oxirredução , Saccharomyces cerevisiaeRESUMO
3-Hydroxypropionate (3HP) is an important platform chemical, and four 3HP biosynthetic routes were reported, in which the malonyl-CoA pathway has some expected advantages but presented the lowest 3HP yield. Here, we demonstrated that this low yield was caused by a serious functional imbalance between MCR-C and MCR-N proteins, responsible for the two-step reduction of malonyl-CoA to 3HP. Then we minimized the enzyme activity imbalance by directed evolution of rate-limiting enzyme MCR-C and fine tuning of MCR-N expression level. Combined with culture conditions optimization, our engineering approaches increased the 3HP titer 270-fold, from 0.15 g/L to 40.6 g/L, representing the highest 3HP production via malonyl-CoA pathway so far. This study not only significantly improved the 3HP productivity of recombinant Escherichia coli strain, but also proved the importance of metabolic balance in a multistep biosynthetic pathway, which should be always considered in any metabolic engineering study.
Assuntos
Escherichia coli/fisiologia , Ácido Láctico/análogos & derivados , Engenharia Metabólica/métodos , Redes e Vias Metabólicas/fisiologia , Oxirredutases/metabolismo , Evolução Molecular Direcionada/métodos , Ativação Enzimática , Ácido Láctico/biossíntese , Ácido Láctico/isolamento & purificação , Complexos Multienzimáticos/genética , Complexos Multienzimáticos/metabolismo , Oxirredutases/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismoRESUMO
OBJECTIVE: Acetyl-CoA is used to produce many valuable metabolites in Escherichia coli. However, acetate overflow is a major shortcoming. Knockout of the global regulator gene, arcA, may solve this problem. RESULTS: The arcA gene of E. coli BL21(DE3) was knocked out, and the production of phloroglucinol (PG) and 3-hydroxypropionate (3HP), both derived from acetyl-CoA, were used to evaluate its effect. The arcA mutants had higher cell yields and higher glucose utilization efficiencies than the corresponding control strains, and the productions of PG and 3HP were 0.92 g/l and 0.27 g/l, respectively; more than twice that of the control strains. Furthermore, arcA knockout also showed significant repression on formation of acetate, the major byproduct in fermentation. Acetate concentrations were decreased 69.4 % and 87 % by arcA knockout during the production of PG and 3HP, respectively. CONCLUSIONS: The arcA gene knockout is a solution to acetate overflow and may improve production of a wide range of acetyl-CoA-derived metabolites.
Assuntos
Acetilcoenzima A/química , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Escherichia coli/genética , Escherichia coli/enzimologia , Proteínas Repressoras/genética , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Fermentação , Deleção de Genes , Regulação Bacteriana da Expressão Gênica , Técnicas de Inativação de Genes , Ácido Láctico/análogos & derivados , Ácido Láctico/metabolismo , Floroglucinol/metabolismoRESUMO
Escherichia coli is one of the most widely used strains for recombinant protein production. However, obstacles also exist in both academic researches and industrial applications, such as the metabolic burden, the carbon source waste, and the cells' physiological deterioration. This article reviews recent approaches for improving recombinant protein production in metabolic engineering, including workhorse selection, stress factor application, and carbon flux regulation. Selecting a suitable host is the first key point for recombinant protein production. In general, it all depends on characteristics of the strains and the target proteins. It will be triggered cells physiological deterioration when the medium is significantly different from the cell's natural environment. Coexpression of stress factors can help proteins to fold into their native conformation. Carbon flux regulation is a direct approach for redirecting more carbon flux toward the desirable pathways and products. However, some undesirable consequences are usually found in metabolic engineering, such as glucose transport inhibition, cell growth retardation, and useless metabolite accumulation. More efficient regulators and platform cell factories should be explored to meet a variety of production demands.
Assuntos
Escherichia coli/genética , Escherichia coli/metabolismo , Engenharia Metabólica/métodos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Carbono/metabolismo , Metabolismo Energético , Escherichia coli/crescimento & desenvolvimentoRESUMO
Ficus species (Moraceae) play pivotal roles in tropical and subtropical ecosystems. Thriving across diverse habitats, from rainforests to deserts, they harbor a multitude of mutualistic and antagonistic interactions with insects, nematodes, and pathogens. Despite their ecological significance, knowledge about the genomic background of Ficus remains limited. In this study, we report a chromosome-level reference genome of F. hirta, with a total size of 297.27 Mb, containing 28,625 protein-coding genes and 44.67% repeat sequences. These findings illuminate the genetic basis of Ficus responses to environmental challenges, offering valuable genomic resources for understanding genome size, adaptive evolution, and co-evolution with natural enemies and mutualists within the genus.
Assuntos
Ficus , Genoma de Planta , Ficus/genética , Cromossomos de Plantas , Tamanho do GenomaRESUMO
The interaction between the nuclear and chloroplast genomes in plants is crucial for preserving essential cellular functions in the face of varying rates of mutation, levels of selection, and modes of transmission. Despite this, identifying nuclear genes that coevolve with chloroplast genomes at a genome-wide level has remained a challenge. In this study, we conducted an evolutionary rate covariation analysis to identify candidate nuclear genes coevolving with chloroplast genomes in Juglandaceae. Our analysis was based on 4,894 orthologous nuclear genes and 76 genes across seven chloroplast partitions in nine Juglandaceae species. Our results indicated that 1,369 (27.97%) of the nuclear genes demonstrated signatures of coevolution, with the Ycf1/2 partition yielding the largest number of hits (765) and the ClpP1 partition yielding the fewest (13). These hits were found to be significantly enriched in biological processes related to leaf development, photoperiodism, and response to abiotic stress. Among the seven partitions, AccD, ClpP1, MatK, and RNA polymerase partitions and their respective hits exhibited a narrow range, characterized by dN/dS values below 1. In contrast, the Ribosomal, Photosynthesis, Ycf1/2 partitions and their corresponding hits, displayed a broader range of dN/dS values, with certain values exceeding 1. Our findings highlight the differences in the number of candidate nuclear genes coevolving with the seven chloroplast partitions in Juglandaceae species and the correlation between the evolution rates of these genes and their corresponding chloroplast partitions.
Assuntos
Genoma de Cloroplastos , Juglandaceae , Filogenia , Evolução Molecular , Juglandaceae/genética , Plastídeos/genética , GenômicaRESUMO
The topological insulator 2D Bi2Se3 is promising for electronic devices due to its unique electronic properties; however, it is challenging to prepare antioxidative nanosheets since Bi2Se3 is prone to oxidation. Surface passivation using ligand agents after Bi2Se3 exfoliation works well to protect the surface, but the process is time-consuming and technically challenging; a passivation agent that is stable under a highly biased potential is significant for in situ passivation of the Bi2Se3 surface. In this work, the roles of halide anions (Cl-, Br-, and I-) in respect of the chemical properties of synthetic Bi2Se3 nanosheets during electrochemical intercalated exfoliation were investigated to determine the antioxidation capacity. It was found that Bi2Se3 nanosheets prepared in a solution of tetrabutylammonium chloride (TBA+ and Cl-) have the best oxidation resistance via the surface bonding of Bi with Cl, which promotes obtaining better device stability. This work paves an avenue for adjusting the components of the electrolyte to further promote the stability of 2D Bi2Se3-nanosheet-based electronic devices.
RESUMO
In lineages of allopolyploid origin, sets of homoeologous chromosomes may coexist that differ in gene content and syntenic structure. Presence or absence of genes and microsynteny along chromosomal blocks can serve to differentiate subgenomes and to infer phylogenies. We here apply genome-structural data to infer relationships in an ancient allopolyploid lineage, the walnut family (Juglandaceae), by using seven chromosome-level genomes, two of them newly assembled. Microsynteny and gene-content analyses yield identical topologies that place Platycarya with Engelhardia as did a 1980s morphological-cladistic study. DNA-alignment-based topologies here and in numerous earlier studies instead group Platycarya with Carya and Juglans, perhaps misled by past hybridization. All available data support a hybrid origin of Juglandaceae from extinct or unsampled progenitors nested within, or sister to, Myricaceae. Rhoiptelea chiliantha, sister to all other Juglandaceae, contains proportionally more DNA repair genes and appears to evolve at a rate 2.6- to 3.5-times slower than the remaining species.
Assuntos
Carya , Juglandaceae , Filogenia , Juglandaceae/genética , Genoma , Carya/genética , Reparo do DNA/genéticaRESUMO
Background: Pancreatic cancer has a high degree of malignancy and high mortality. Understanding its biological status can provide more therapeutic targets for the future. The present study was to investigate whether curcumin can inhibit pancreatic cancer cell proliferation by regulating Beclin1 expression and inhibiting the hypoxia-inducible factor-1α (HIF-1α)-mediated glycolytic pathway. Methods: Two pancreatic cancer cell lines, PANC-1 and SW1990, were treated with different concentrations of curcumin (0, 20, 40, and 60 µM). Cell viability was detected using the Cell Counting Kit-8 (CCK-8) assay and flow cytometry was performed to determine the apoptosis rate and cell cycle arrest of the pancreatic cancer cells. PANC-1 and SW1990 cells were treated with different concentrations of curcumin under hypoxic conditions for 48 hours to detect the relative expression of the Beclin1 protein. The co-immunoprecipitation (co-IP) method was used to determine whether curcumin could inhibit the interaction between Beclin1 and HIF-1α. Results: The proliferation inhibition rates of PANC-1 cells after exposure to 0, 20, 40, and 60 µM curcumin were 0%, 31.6%, 47.2%, and 63.9%, respectively, and that of SW1990 cells were 0%, 18.8%, 46.3%, and 63.5% respectively. Western blot analyses showed decreased expression of Beclin1 in cells treated with curcumin. The expression of Beclin1 in the nucleus and cytoplasm decreased with increasing concentrations of curcumin. Co-IP results demonstrated that curcumin inhibited the interaction between Beclin1 and HIF-1α. Treatment with the higher doses of curcumin (40 and 60 µM) significantly decreased the protein expression levels of HIF-1α. In addition, the expression levels of Kidney-Specific Cadherin (HSP70, HSP90, and von Hippel-Lindau protein (pVHL) were significantly decreased in pancreatic cancer cells while the expression of prolyl hydroxylase (PHD) and receptor of activated protein kinase C (RACK1) increased significantly. Furthermore, curcumin reduced cellular adenosine triphosphate (ATP) production in a dose-dependent manner. Compared with control pancreatic cancer cells, the expression levels of GLUT1, HK2, LDHA, and PDK1 gradually decreased with increasing curcumin concentrations. Conclusions: Curcumin can inhibit the expression of Beclin1 and HIF-1α in pancreatic cancer cells under anoxic conditions, thereby affecting the glycolysis pathway and inhibiting cell proliferation.
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As an evolutionarily conserved posttranslational modification, protein lysine acetylation plays important roles in many physiological and metabolic processes. However, there are few reports about the applications of lysine acetylation in metabolic regulations. Lactate is a main byproduct in microbial fermentation, and itself also an important bulk chemical with considerable commercial values in many fields. Lactate dehydrogenase (LdhA) is the key enzyme catalyzing lactate synthesis from pyruvate. Here, we reported that Escherichia coli LdhA can be acetylated and the acetylated lysine sites were identified by mass spectrometry. The effects and regulatory mechanisms of acetylated sites on LdhA activity were characterized. Finally, lysine acetylation was successfully used to regulate the lactate synthesis. LdhA (K9R) mutant overexpressed strain improved the lactate titer and glucose conversion efficiency by 1.74 folds than that of wild-type LdhA overexpressed strain. LdhA (K154Q-K248Q) mutant can inhibit lactate accumulation and improve 3HP production. Our study established a paradigm for lysine acetylation in lactate synthesis regulation and suggested that lysine acetylation may be a promising strategy to improve the target production and conversion efficiency in microbial synthesis. The application of lysine acetylation in regulating lactate synthesis also provides a reference for the treatment of lactate-related diseases.