scholarly journals Recent Research Progress in Taxol Biosynthetic Pathway and Acylation Reactions Mediated by Taxus Acyltransferases

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2855
Author(s):  
Tao Wang ◽  
Lingyu Li ◽  
Weibing Zhuang ◽  
Fengjiao Zhang ◽  
Xiaochun Shu ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Structural Diversity ◽  
Underlying Mechanism ◽  
Research Progress ◽  
Enzymatic Reactions ◽  
Acylation Reaction ◽  
Taxol Biosynthesis ◽  
The Core ◽  
Coa Ligase ◽  
Acylation Reactions

Taxol is one of the most effective anticancer drugs in the world that is widely used in the treatments of breast, lung and ovarian cancer. The elucidation of the taxol biosynthetic pathway is the key to solve the problem of taxol supply. So far, the taxol biosynthetic pathway has been reported to require an estimated 20 steps of enzymatic reactions, and sixteen enzymes involved in the taxol pathway have been well characterized, including a novel taxane-10β-hydroxylase (T10βOH) and a newly putative β-phenylalanyl-CoA ligase (PCL). Moreover, the source and formation of the taxane core and the details of the downstream synthetic pathway have been basically depicted, while the modification of the core taxane skeleton has not been fully reported, mainly concerning the developments from diol intermediates to 2-debenzoyltaxane. The acylation reaction mediated by specialized Taxus BAHD family acyltransferases (ACTs) is recognized as one of the most important steps in the modification of core taxane skeleton that contribute to the increase of taxol yield. Recently, the influence of acylation on the functional and structural diversity of taxanes has also been continuously revealed. This review summarizes the latest research advances of the taxol biosynthetic pathway and systematically discusses the acylation reactions supported by Taxus ACTs. The underlying mechanism could improve the understanding of taxol biosynthesis, and provide a theoretical basis for the mass production of taxol.

scholarly journals Differential Triggering of the Phenylpropanoid Biosynthetic Pathway Key Genes Transcription upon Cold Stress and Viral Infection in Tomato Leaves

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 448
Author(s):  
Polyxeni Pappi ◽  
Nikolaos Nikoloudakis ◽  
Dimitrios Fanourakis ◽  
Antonios Zambounis ◽  
Costas Delis ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Viral Infection ◽  
Cold Stress ◽  
Biosynthetic Pathway ◽  
Molecular Mechanisms ◽  
Gene Families ◽  
Total Phenolic ◽  
Defense Strategies ◽  
The Core ◽  
Coa Ligase

Plants develop a plethora of defense strategies during their acclimation and interactions with various environmental stresses. Secondary metabolites play a pivotal role in the processes during stress acclimation, therefore deciphering their relevant responses exchange the interpretation of the underlying molecular mechanisms that may contribute to improved adaptability and efficacy. In the current study, tomato plants were exposed to short-term cold stress (5 °C for 16 h) or inoculated (20 d) with either Cucumber Mosaic Virus (CMV) or Potato Virus Y (PVY). Responses were recorded via the assessments of leaf total phenolic (TP) content, total flavonoid (TF) levels, and phenylalanine ammonia-lyase (PAL) enzyme activity. The transcription of the gene families regulating the core phenylpropanoid biosynthetic pathway (PBP) at an early (PAL, cinnamic acid 4-hydroxylase, 4-coumarate-CoA ligase) or late (chalcone synthase and flavonol synthase) stage was also evaluated. The results showed that cold stress stimulated an increase in TP and TF contents, while PAL enzyme activity was also elevated compared to viral infection. Besides genes transcription of the enzymes involved in the core PBP was mostly induced by cold stress, whereas transcription of the genes regulating flavonoid biosynthesis was mainly triggered by viral infection. In conclusion, abiotic and biotic stressors induced differential regulation of the core PBP and flavonoid biosynthetic metabolism. Taking the above into consideration, our results highlight the complexity of tomato responses to diverse stimuli allowing for better elucidation of stress tolerance mechanisms at this crop.

Enzymatic dimerization in the biosynthetic pathway of microbial natural products

2021 ◽  
Author(s):  
Jiawang Liu ◽  
Anan Liu ◽  
Youcai Hu
Keyword(s):  
Natural Products ◽  
Biosynthetic Pathway ◽  
Structural Diversity ◽  
Cytochrome P450s ◽  
Microbial Natural Products

Cytochrome P450s, laccases, and intermolecular [4 + 2] cyclases, along with other enzymes were utilized to catalyze varied dimerization of matured natural products so as to create the structural diversity and complexity in microorganisms.

On the Structural Diversity of Sialoliths

2007 ◽  
Vol 13 (5) ◽  
pp. 390-396 ◽  
Author(s):  
António P. Alves de Matos ◽  
Patrícia A. Carvalho ◽  
Arlindo Almeida ◽  
Luís Duarte ◽  
Rui Vilar ◽  
...  
Keyword(s):  
Formation Process ◽  
Structural Diversity ◽  
Growth Stages ◽  
Layer Formation ◽  
Organic Layers ◽  
The Core ◽  
Significant Variability ◽  
Multiple Cores ◽  
Laminated Structures

Sialoliths from parotid and submaxillar glands have been characterized. Fractured and polished surfaces revealed an intrinsic structural diversity across the calculi sections. In general, the calculi presented highly mineralized amorphous-looking cores surrounded by concentric alternating mineralized and organic layers. The thickness of these layers decreased from the outer regions toward the center of the sialolith, illustrating a sequence of growth stages. Nevertheless, a significant variability could be detected among the specimens. In some cases, the calculi displayed multiple cores and lacked concentric laminated structures. In other instances, the specimens exhibited extensive regions of globular structures. In these cases, the globule diameter decreased across the radius toward the center of the sialoliths, and the globular structures tended to reorganize, forming bright and dark laminated layers surrounding the core. The participation of globular structures in the layer formation process points to morphogenetic mechanisms not previously described.

scholarly journals One-Seeded Fruits in the Core Caryophyllales: Their Origin and Structural Diversity

PLoS ONE ◽  
2015 ◽  
Vol 10 (2) ◽  
pp. e0117974 ◽  
Author(s):  
Alexander P. Sukhorukov ◽  
Evgeny V. Mavrodiev ◽  
Madeleen Struwig ◽  
Maya V. Nilova ◽  
Khalima Kh. Dzhalilova ◽  
...  
Keyword(s):  
Structural Diversity ◽  
The Core

Research Progress of Phosphorus Removal in Enhanced Coagulation

2012 ◽  
Vol 518-523 ◽  
pp. 1825-1830
Author(s):  
Chao Chun Tang ◽  
Peng Hui Shao ◽  
Mei Peng Jian ◽  
He Gen Yu
Keyword(s):  
Phosphorus Removal ◽  
Lower Cost ◽  
Research Progress ◽  
Enhanced Coagulation ◽  
The Core ◽  
Removal Technology ◽  
New Type

Phosphorus is one of the prime cause of eutrophication,the research of phosphorus removal technology catches the most attention all the time.This paper is focusing on introducing the application and development of the solutions for the phosphorus removal, such as new type of coagulant, new coagulation craft and new flocculation reactor.It points out the core problems in restricting the development of the methods of enhanced coagulation in phosphorus removal ，and gives a clear direction for the research of the methods of enhanced coagulation in phosphorus removal.The enhanced coagulation technology at lower cost and less energy is worth deeply researching.

scholarly journals Differential Regulation of NF-κB by Elongation Factors Is Determined by Core Promoter Type

2007 ◽  
Vol 27 (14) ◽  
pp. 5246-5259 ◽  
Author(s):  
Liat Amir-Zilberstein ◽  
Elena Ainbinder ◽  
Leanne Toube ◽  
Yuki Yamaguchi ◽  
Hiroshi Handa ◽  
...  
Keyword(s):  
Immune Response ◽  
Transcription Factors ◽  
Rna Polymerase Ii ◽  
Target Genes ◽  
Core Promoter ◽  
Underlying Mechanism ◽  
Differential Regulation ◽  
Elongation Factors ◽  
The Core ◽  
Regulatory Link

ABSTRACT NF-κB transcription factors activate genes important for immune response, inflammation, and cell survival. P-TEFb and DSIF, which are positive and negative transcription elongation factors, respectively, both regulate NF-κB-induced transcription, but the mechanism underlying their recruitment to NF-κB target genes is unknown. We show here that upon induction of NF-κB, a subset of target genes is regulated differentially by either P-TEFb or DSIF. The regulation of these genes and their occupancy by these elongation factors are dependent on the NF-κB enhancer and the core promoter type. Converting a TATA-less promoter to a TATA promoter switches the regulation of NF-κB from DSIF to P-TEFb. Accumulation or displacement of DSIF and P-TEFb is dictated by the formation of distinct initiation complexes (TFIID dependent or independent) on the two types of core promoter. The underlying mechanism for the dissociation of DSIF from TATA promoters upon NF-κB activation involves the phosphorylation of RNA polymerase II by P-TEFb. The results highlight a regulatory link between the initiation and the elongation phases of the transcription reaction and broaden our comprehension of the NF-κB pathway.

scholarly journals Acetamido Sugar Biosynthesis in the Euryarchaea

2008 ◽  
Vol 190 (8) ◽  
pp. 2987-2996 ◽  
Author(s):  
Seema C. Namboori ◽  
David E. Graham
Keyword(s):  
Biosynthetic Pathway ◽  
Comparative Sequence Analysis ◽  
Core Oligosaccharide ◽  
Methanococcus Maripaludis ◽  
The Core ◽  
Capsule Production ◽  
Lipopolysaccharide Biosynthesis ◽  
Genes Encoding ◽  
Large Families ◽  
Coenzyme B

ABSTRACT Archaea and eukaryotes share a dolichol phosphate-dependent system for protein N-glycosylation. In both domains, the acetamido sugar N-acetylglucosamine (GlcNAc) forms part of the core oligosaccharide. However, the archaeal Methanococcales produce GlcNAc using the bacterial biosynthetic pathway. Key enzymes in this pathway belong to large families of proteins with diverse functions; therefore, the archaeal enzymes could not be identified solely using comparative sequence analysis. Genes encoding acetamido sugar-biosynthetic proteins were identified in Methanococcus maripaludis using phylogenetic and gene cluster analyses. Proteins expressed in Escherichia coli were purified and assayed for the predicted activities. The MMP1680 protein encodes a universally conserved glucosamine-6-phosphate synthase. The MMP1077 phosphomutase converted α-d-glucosamine-6-phosphate to α-d-glucosamine-1-phosphate, although this protein is more closely related to archaeal pentose and glucose phosphomutases than to bacterial glucosamine phosphomutases. The thermostable MJ1101 protein catalyzed both the acetylation of glucosamine-1-phosphate and the uridylyltransferase reaction with UTP to produce UDP-GlcNAc. The MMP0705 protein catalyzed the C-2 epimerization of UDP-GlcNAc, and the MMP0706 protein used NAD+ to oxidize UDP-N-acetylmannosamine, forming UDP-N-acetylmannosaminuronate (ManNAcA). These two proteins are similar to enzymes used for proteobacterial lipopolysaccharide biosynthesis and gram-positive bacterial capsule production, suggesting a common evolutionary origin and a widespread distribution of ManNAcA. UDP-GlcNAc and UDP-ManNAcA biosynthesis evolved early in the euryarchaeal lineage, because most of their genomes contain orthologs of the five genes characterized here. These UDP-acetamido sugars are predicted to be precursors for flagellin and S-layer protein modifications and for the biosynthesis of methanogenic coenzyme B.

scholarly journals Knowledge Mapping of Research on Land Use Change and Food Security: A Visual Analysis Using CiteSpace and VOSviewer

2021 ◽  
Vol 18 (24) ◽  
pp. 13065
Author(s):  
Peng Cheng ◽  
Houtian Tang ◽  
Yue Dong ◽  
Ke Liu ◽  
Ping Jiang ◽  
...  
Keyword(s):  
Land Use ◽  
Food Security ◽  
Land Use Change ◽  
Visual Analysis ◽  
Rapid Development ◽  
Academic Community ◽  
Research Progress ◽  
The Core ◽  
Geographical Regions ◽  
The Impact

Many scholars have conducted in-depth research on the theme of land use change and food security, and formed fruitful research results, but there is a lack of quantitative analysis and comprehensive evaluation of research achievements. Therefore, based on the relevant literature on the theme of land use change and food security in the core collection of the Web of Science (WOS) database, this paper takes the advantage of CiteSpace and VOSviewer bibliometric software to draw the cooperative network and keyword cooccurrence map to analyze the research progress and frontier. The results reveal that: (1) The research started in 1999 and can be divided into three stages: initial research, rapid development, and a stable in-depth stage. This topic has increasingly become a research hotspot in the academic community. (2) The distribution of research institutions is concentrated and forms a small cluster, and the research networks between developed and developing countries have been established, and developed countries are in the core position, but the cooperation network is not prominent. (3) The research content is becoming increasingly organized and systematic, and the research hot topics are divided into seven aspects. (4) The research area of the subject covers multiple levels, such as global, national, and specific natural geographical regions, and has formed a research system of geographic information technology and satellite remote sensing technology. It also presents the trend of cross integration with economics, land management and soil science. In the future, theoretical innovation still needs to be strengthened, and we should strengthen the research on the impact of agricultural chemical fertilizers on food security and study the impact of urban expansion on land use change.

scholarly journals The Biosynthetic Pathway of Major Avenanthramides in Oat

Metabolites ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 163 ◽  
Author(s):  
Zhiyong Li ◽  
Yi Chen ◽  
Dauenpen Meesapyodsuk ◽  
Xiao Qiu
Keyword(s):  
Biosynthetic Pathway ◽  
Molecular Mechanisms ◽  
Functional Characterization ◽  
Acyl Donor ◽  
Acyl Acceptor ◽  
Coa Ligase ◽  
Health Promoting ◽  
Hydroxyanthranilic Acid ◽  
Coa Thioesters

Avenanthramides are a group of N-cinnamoylanthranilic acids, with health-promoting properties mainly found in oat (Avena sativa L.). However, the biosynthetic mechanism for the main three types of avenanthramides (Avn-A, Avn-B and Avn-C) is not completely understood. In the present study, we report molecular identification and functional characterization of three different types of genes from oat encoding 4-coumarate-CoA ligase (4CL), hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyl transferase (HHT) and a caffeoyl-CoA O-methyltransferase (CCoAOMT) enzymes, all involved in the biosynthesis of these avenanthramides. In vitro enzymatic assays using the proteins expressed in Escherichia coli showed that oat 4CL could convert p-coumaric acid, caffeic acid and ferulic acid to their CoA thioesters. Oat HHTs were only responsible for the biosynthesis of Avn-A and Avn-C using hydroxyanthranilic acid as an acyl acceptor and p-coumaroyl-CoA and caffeoyl-CoA as an acyl donor, respectively. Avn-B was synthesized by a CCoAOMT enzyme through the methylation of Avn-C. Collectively, these results have elucidated the molecular mechanisms for the biosynthesis of three major avenanthramides in vitro and paved the way for metabolic engineering of the biosynthetic pathway in heterologous systems to produce nutraceutically important compounds and make possible genetic improvement of this nutritional trait in oat through marker-assisted breeding.

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