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1.
Mol Plant Microbe Interact ; 36(9): 592-604, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37102770

RESUMO

Phytocytokines are signaling peptides that alert plant cells of danger. However, the downstream responses triggered by phytocytokines and their effect on plant survival are still largely unknown. Here, we have identified three biologically active maize orthologues of phytocytokines previously described in other plants. The maize phytocytokines show common features with microbe-associated molecular patterns (MAMPs), including the induction of immune-related genes and activation of papain-like cysteine proteases. In contrast to MAMPs, phytocytokines do not promote cell death in the presence of wounding. In infection assays with two fungal pathogens, we found that phytocytokines affect the development of disease symptoms, likely due to the activation of phytohormonal pathways. Collectively, our results show that phytocytokines and MAMPs trigger unique and antagonistic features of immunity. We propose a model in which phytocytokines activate immune responses partially similar to MAMPs but, in contrast to microbial signals, they act as danger and survival molecules to the surrounding cells. Future studies will focus on the components determining the divergence of signaling outputs upon phytocytokine activation. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.


Assuntos
Imunidade Vegetal , Zea mays , Plantas , Transdução de Sinais , Morte Celular , Doenças das Plantas/microbiologia
2.
Angew Chem Int Ed Engl ; 62(39): e202309053, 2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37486685

RESUMO

Herein, we describe the feasibility of atroposelective PIII /PV =O redox organocatalysis by the Staudinger-aza-Wittig reaction. The formation of isoquinoline heterocycles thereby enables the synthesis of a broad range of valuable atropisomers under mild conditions with enantioselectivities of up to 98 : 2 e.r. Readily prepared azido cinnamate substrates convert in high yield with stereocontrol by a chiral phosphine catalyst, which is regenerated using a silane reductant under Brønsted acid co-catalysis. The reaction provides access to diversified aryl isoquinolines, as well as benzoisoquinoline and naphthyridine atropisomers. The products are expeditiously transformed into N-oxides, naphthol and triaryl phosphine variants of prevalent catalysts and ligands. With dinitrogen release and aromatization as ideal driving forces, it is anticipated that atroposelective redox organocatalysis provides access to a multitude of aromatic heterocycles with precise control over their configuration.

3.
Angew Chem Int Ed Engl ; 61(24): e202202548, 2022 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-35343034

RESUMO

Simultaneous control over the configuration of multiple stereocenters is accomplished by numerous catalytic methods, providing a reliable basis for the synthesis of stereochemically complex targets in isomerically defined form. In contrast, addressing the configurations of multiple stereogenic axes with diastereodivergent catalyst control is thus far only possible by stepwise approaches. Herein we now describe that all four stereoisomers of atropisomeric two-axis systems are directly tractable by assembling a central aromatic unit of teraryls through an arene-forming aldol condensation. By using cinchona alkaloid-based ion-pairing catalysts, the four feasible reaction pathways are differentiated from identical substrates under defined basic conditions without preactivation, thus enabling complete stereodivergence with enantioselectivities of up to 99 : 1 e.r.


Assuntos
Aldeídos , Alcaloides de Cinchona , Catálise , Estereoisomerismo
4.
Toxicol Appl Pharmacol ; 430: 115727, 2021 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-34543670

RESUMO

Electronic cigarettes (e-cigarettes) have gained increasing popularity in recent years, mostly because they are supposed to be less harmful than regular cigarettes. Therefore, it is highly imperative to investigate possible noxious effects to protect the consumers. E-liquids consist of propylene glycol, glycerol, aroma compounds and sweeteners. One of these sweeteners is a chlorinated version of sucrose, namely sucralose. The aim of this work was to investigate degradation products of sucralose in the presence of propylene glycol and glycerol at different temperatures of commercially available e-cigarettes. Chemical analysis and biological tests were simultaneously performed on e-liquid aerosol condensates. The results of the chemical analysis, which was executed by employing GC-MS/GC-FID, demonstrated high amounts of various chloropropanols. The most abundant one is extremely toxic, namely 3-chloropropane-1,2-diol, which can be detected at concentrations ranging up to 10,000 mg/kg. Furthermore, a cytotoxicity investigation of the condensates was performed on HUVEC/Tert2 cells in which metabolic activity was determined by means of resazurin assay. The cellular metabolic activity significantly decreased by treatment with e-liquid aerosol condensate. Due to the results of this study, we advise against the use of sucralose as sweetener in e-liquids.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Glicerol/toxicidade , Propilenoglicol/toxicidade , Sacarose/análogos & derivados , Edulcorantes/toxicidade , Vaping/efeitos adversos , alfa-Cloridrina/toxicidade , Células Cultivadas , Qualidade de Produtos para o Consumidor , Estabilidade de Medicamentos , Glicerol/química , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Propilenoglicol/química , Medição de Risco , Sacarose/química , Sacarose/toxicidade , Edulcorantes/química , Temperatura , Testes de Toxicidade , Volatilização , alfa-Cloridrina/química
5.
Chimia (Aarau) ; 74(9): 699-703, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-32958107

RESUMO

Aldol reactions belong to the most important methods for carbon-carbon bond formation and are also involved in one of the most astonishing biosynthetic processes: the biosynthesis of polyketides governed by an extraordinarily sophisticated enzymatic machinery. In contrast to the typical linear or convergent strategies followed in chemical synthesis, this late-stage catalysis concept allows Nature to assemble intermediates that are diversified into a broad range of scaffolds, which assume various crucial biological functions. To transfer this concept to small-molecule catalysis to access products beyond the natural systems, a stepwise approach to differentiate increasingly complex substrates was followed by investigating arene-forming polyketide cyclizations. An outline of our efforts to develop and apply these concepts are presented herein.


Assuntos
Policetídeos , Catálise , Ciclização , Metabolismo Secundário
6.
Planta ; 249(1): 221-233, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30470899

RESUMO

MAIN CONCLUSION: Modular assembly and heterologous expression in the moss Physcomitrella patens of pairs of diterpene synthases results in accumulation of modern land plant diterpenoids. Physcomitrella patens is a representative of the ancient bryophyte plant lineage with a genome size of 511 Mb, dominant haploid life cycle and limited chemical and metabolic complexity. For these plants, exceptional capacity for genome editing through homologous recombination is met with recently demonstrated in vivo assembly of multiple heterologous DNA fragments. These traits earlier made P. patens an attractive choice as a biotechnological chassis for photosynthesis-driven production of recombinant peptides. The lack of diterpene gibberellic acid phytohormones in P. patens combined with the recent targeted disruption of the single bifunctional diterpene synthase yielded lines devoid of endogenous diterpenoid metabolites and well-suited for engineering of terpenoid production. Here, we mimicked the modular nature of diterpene biosynthetic pathways found in modern land plants by developing a flexible pipeline to install three combinations of class II and class I diterpene synthases in P. patens to access industrially relevant diterpene biomaterials. In addition to a well-established neutral locus for targeted integration, we also explored loci created by a class of Long Terminal Repeat Retrotransposon present at moderate number in the genome of P. patens. Assembly of the pathways and production of the enzymes from the neutral locus led to accumulation of diterpenes matching the reported activities in the angiosperm sources. In contrast, insights gained with the retrotransposon loci indicate their suitability for targeting, but reveal potentially inherent complications which may require adaptation of the experimental design.


Assuntos
Biotecnologia/métodos , Diterpenos/metabolismo , Bryopsida/metabolismo , Giberelinas/metabolismo , Estágios do Ciclo de Vida/fisiologia , Fotossíntese/fisiologia , Reguladores de Crescimento de Plantas/metabolismo , Retroelementos/genética , Biologia Sintética/métodos
7.
Int Braz J Urol ; 45(2): 354-360, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30735337

RESUMO

OBJECTIVE: To propose a new way to objectively evaluate the external sphincter function prior to male sling surgery. MATERIALS AND METHODS: We evaluated the pre-operative sphincter function throughout sphincter pressure at rest (SPAR) and sphincter pressure under contraction (SPUC) obtained throughout urethral profilometry profile (UPP) of 10 consecutive patients (age range, 54-79 years) treated with the retrourethral transobturator sling (RTS) for stress urinary incontinence (SUI) because of prostate surgery. The primary endpoint for surgery success rate was post-operative pad weight test. This was correlated to preoperative pad test, RT, SPAR and SPUC. Post-operatively patients were classified as continent (no pad use) and those who still were incontinent. RESULTS: Mean SPUC in the continent and incontinent group was respectively 188 + 8.8 (median 185.1, range 181 to 201) and 96.9 + 49.4 (median 109.9, range 35.6 to 163.6) (P = 0.008). Mean 24-hour pad test was 151 + 84.2gm (median 140, range 80 to 245) and 973 + 337.1gm (median 1940, range 550 to 1200) in post-operative continent and incontinent groups respectively (P = 0.008). The repositioning test (RT) was positive in all continent patients except one. The RT was also positive in three incontinence patients (false positive). In all post-operative continent patients SPUC was higher than 180cmH2O and pre-operative pad test was less than 245gm. CONCLUSIONS: SPUC seems to be a way for optimizing the sphincter evaluation as well to become a useful tool for patient selection prior to RTS surgery.


Assuntos
Esfíncter Esofágico Inferior/fisiologia , Prostatectomia/efeitos adversos , Slings Suburetrais/efeitos adversos , Incontinência Urinária por Estresse/etiologia , Esfíncter Urinário Artificial/efeitos adversos , Idoso , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Incontinência Urinária por Estresse/cirurgia
8.
J Urol ; 200(6): 1338-1343, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30563652

RESUMO

PURPOSE: Many providers elect to use a transcorporeal approach for artificial urinary sphincter placement in an attempt to minimize risks, given the increased risk of complications in revision cases. We present outcomes in a multicenter retrospective analysis of artificial urinary sphincter cuff reimplantation in patients with prior cuff erosion with special consideration given to the transcorporeal approach. MATERIALS AND METHODS: We compiled a multi-institutional database of patients who underwent artificial urinary sphincter reimplantation after prior urethral erosion. Of the 34 identified patients 24 underwent transcorporeal cuff replacement. Patients with transcorporeal cuff replacement were further analyzed with specific stratification for radiation therapy. RESULTS: The rate of subsequent complications after eroded cuff reimplantation was 32.4% (11 of 34 patients). The most frequent complication was recurrent erosion, which developed in 9 of the 34 patients (26.4%). Repeat artificial urinary sphincter complications developed more frequently in patients with history of radiation compared to nonirradiated patients (8 of 16 or 50% vs 3 of 18 or 16.7%). However, this difference was not statistically significant (p = 0.066). The transcorporeal technique was applied in 24 of 33 patients (70.5%) and relative to the nontranscorporeal group there was no difference in the complication rate (p = 0.438). On subgroup analysis of the transcorporeal group there was a higher rate of repeat complications in irradiated patients (p = 0.006). CONCLUSIONS: These data suggest that transcorporeal cuff reimplantation may not decrease the incidence of repeat complications after prior cuff erosion. However, radiation therapy is associated with a worse outcome even when transcorporeal cuff placement is performed.


Assuntos
Complicações Pós-Operatórias/prevenção & controle , Implantação de Prótese/efeitos adversos , Reoperação/efeitos adversos , Uretra/efeitos da radiação , Doenças Uretrais/cirurgia , Esfíncter Urinário Artificial/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada/efeitos adversos , Terapia Combinada/métodos , Humanos , Masculino , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Prostatectomia/efeitos adversos , Prostatectomia/métodos , Neoplasias da Próstata/cirurgia , Implantação de Prótese/métodos , Reoperação/métodos , Estudos Retrospectivos , Resultado do Tratamento , Uretra/patologia , Uretra/cirurgia , Doenças Uretrais/patologia
9.
Angew Chem Int Ed Engl ; 57(34): 11035-11039, 2018 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-29969531

RESUMO

The functionalization of aminoheterocycles by using a pyrylium tetrafluoroborate reagent (Pyry-BF4 ) is presented. This reagent efficiently condenses with a great variety of heterocyclic amines and primes the C-N bond for nucleophilic aromatic substitution. More than 60 examples for the formation of C-O, C-N, C-S, or C-SO2 R bonds are disclosed herein. In contrast to C-N activation through diazotization and polyalkylation, this method is characterized by its mild conditions and impressive functional-group tolerance. In addition to small-molecule derivatization, Pyry-BF4 allows the introduction of functional groups in a late-stage fashion to furnish highly functionalized structures.

10.
Bioorg Med Chem Lett ; 27(5): 1193-1198, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28169169

RESUMO

In silico screening of DrugBank database to detect liver X receptor (LXR) agonism of marketed drugs using a self-organizing map and successive LXR-Gal4 hybrid reporter gene assay evaluation in vitro discovered alitretinoin and bexarotene as partial liver X receptor agonists. Dose-response curves demonstrated that plasma concentrations observed in clinical trials are sufficient for LXR activation and thus could account for LXR-mediated side-effects such as hypercholesterolemia and hyperlipidemia. The discovered drugs are the first reported dual LXR/RXR agonists and can serve as lead structures for LXR and dual LXR/RXR modulator development.


Assuntos
Receptores X do Fígado/efeitos dos fármacos , Tetra-Hidronaftalenos/farmacologia , Tretinoína/farmacologia , Alitretinoína , Animais , Bexaroteno , Avaliação Pré-Clínica de Medicamentos , Células HEK293 , Humanos , Receptores X do Fígado/genética , Camundongos
12.
Bioorg Med Chem Lett ; 25(22): 5243-6, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-26463134

RESUMO

Bacterial resistance mediated by metallo-ß-lactamases (MBLs) is a major problem for the treatment of infections. An MBL inhibitor could restore the potency of ß-lactam antibiotics. Fragment-based design might deliver valuable starting points for the discovery of novel MBL inhibitors. In this study, we chose an in silico approach to search for fragments able to bind and inhibit NDM-1, VIM-1, and IMP-7. We used consensus docking to identify low molecular weight compounds from a commercially available library. Most promising compounds were evaluated in a sensitive fluorescence-based activity assay and by the orthogonal biophysical technique saturation transfer difference (STD)-NMR. (1)H-(15)N chemical shift perturbation NMR was used to confirm the reversible binding and measure the dissociation constant of the most promising compound qualifying it as a high-quality starting point for further optimization.


Assuntos
Simulação de Acoplamento Molecular , Inibidores de beta-Lactamases/química , beta-Lactamases/química , Benzopiranos/química , Simulação por Computador , Fluorescência , Resistência beta-Lactâmica
13.
J Chem Inf Model ; 55(2): 207-13, 2015 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-25629725

RESUMO

VAMMPIRE-LORD (lead optimization by rational design) describes an innovative strategy to improve the binding affinity of a defined lead compound using 3D matched molecular pairs (3D-MMPs). 3D-MMPs are defined as pairs of molecules that differ in exactly one structural transformation and have a known bioactive conformation. We developed a novel atom-pair descriptor (LORD_FP) that represents the ligand-as well as the receptor environment-of a chemical transformation and built a predictive model based on 17602 3D-MMPs. We demonstrate that the created model is able to extrapolate the knowledge of a chemical transformation and the associated effect on ligand affinity to any similar system. VAMMPIRE-LORD was implemented as a web server that guides the user step-by-step through the optimization process of a defined lead compound.


Assuntos
Bases de Dados de Compostos Químicos , Descoberta de Drogas/métodos , Internet/instrumentação , Algoritmos , Inibidores de Ciclo-Oxigenase 2/química , Inibidores de Ciclo-Oxigenase 2/farmacologia , Descoberta de Drogas/instrumentação , Previsões , Ligantes , Modelos Moleculares , Conformação Molecular , Software , Relação Estrutura-Atividade
14.
J Chem Inf Model ; 55(2): 284-93, 2015 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-25625859

RESUMO

The pharmacophore concept is commonly employed in virtual screening for hit identification. A pharmacophore is generally defined as the three-dimensional arrangement of the structural and physicochemical features of a compound responsible for its affinity to a pharmacological target. Given a number of active ligands binding to a particular target in the same manner, it can reasonably be assumed that they have some shared features, a common pharmacophore. We present a growing neural gas (GNG)-based approach for the extraction of the relevant features which we called PENG (pharmacophore elucidation by neural gas). Results of retrospective validation indicate an acceptable quality of the generated models. Additionally a prospective virtual screening for leukotriene A4 hydrolase (LTA4H) inhibitors was performed. LTA4H is a bifunctional zinc metalloprotease which displays both epoxide hydrolase and aminopeptidase activity. We could show that the PENG approach is able to predict the binding mode of the ligand by X-ray crystallography. Furthermore, we identified a novel chemotype of LTA4H inhibitors.


Assuntos
Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Epóxido Hidrolases/antagonistas & inibidores , Ensaios de Triagem em Larga Escala/métodos , Redes Neurais de Computação , Algoritmos , Aminopeptidases/química , Benchmarking , Cristalografia por Raios X , Epóxido Hidrolases/química , Humanos , Ligantes , Modelos Moleculares , Estudos Prospectivos , Ligação Proteica , Reprodutibilidade dos Testes , Termodinâmica
15.
Int J Pharm ; : 124412, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38960339

RESUMO

Process Analytical Technology (PAT) has revolutionized pharmaceutical manufacturing by providing real-time monitoring and control capabilities throughout the production process. This review paper comprehensively examines the application of PAT methodologies specifically in the production of solid active pharmaceutical ingredients (APIs). Beginning with an overview of PAT principles and objectives, the paper explores the integration of advanced analytical techniques such as spectroscopy, imaging modalities and others into solid API substance production processes. Novel developments in in-line monitoring at academic level are also discussed. Emphasis is placed on the role of PAT in ensuring product quality, consistency, and compliance with regulatory requirements. Examples from existing literature illustrate the practical implementation of PAT in solid API substance production, including work-up, crystallization, filtration, and drying processes. The review addresses the quality and reliability of the measurement technologies, aspects of process implementation and handling, the integration of data treatment algorithms and current challenges. Overall, this review provides valuable insights into the transformative impact of PAT on enhancing pharmaceutical manufacturing processes for solid API substances.

16.
Front Big Data ; 7: 1366469, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38665785

RESUMO

Particle accelerators play a crucial role in scientific research, enabling the study of fundamental physics and materials science, as well as having important medical applications. This study proposes a novel graph learning approach to classify operational beamline configurations as good or bad. By considering the relationships among beamline elements, we transform data from components into a heterogeneous graph. We propose to learn from historical, unlabeled data via our self-supervised training strategy along with fine-tuning on a smaller, labeled dataset. Additionally, we extract a low-dimensional representation from each configuration that can be visualized in two dimensions. Leveraging our ability for classification, we map out regions of the low-dimensional latent space characterized by good and bad configurations, which in turn can provide valuable feedback to operators. This research demonstrates a paradigm shift in how complex, many-dimensional data from beamlines can be analyzed and leveraged for accelerator operations.

17.
JACS Au ; 3(10): 2612-2630, 2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-37885579

RESUMO

Alongside enantioselective catalysis, synthetic chemists are often confronted by the challenge of achieving catalyst control over the relative configuration to stereodivergently access desired diastereomers. Typically, these approaches iteratively or simultaneously control multiple stereogenic units for which dual catalytic methods comprising sequential, relay, and synergistic catalysis emerged as particularly efficient strategies. In this Perspective, the benefits and challenges of catalyst-controlled diastereodivergence in the construction of carbon stereocenters are discussed on the basis of illustrative examples. The concepts are then transferred to diastereodivergent catalysis for atropisomeric systems with twofold and higher-order stereogenicity as well as diastereodivergent catalyst control over E- and Z-configured alkenes.

18.
J Robot Surg ; 17(4): 1341-1347, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36930424

RESUMO

The new SP robot incorporates a single trocar that houses a flexible camera and three bi-articulated arms, which minimize the number of incisions needed to assess the surgical site, allowing for a less invasive procedure. To compare the postoperative pain scale and outcomes in patients with similar demographic characteristics undergoing robotic-assisted radical prostatectomy (RARP) with SP and Xi robots, One-hundred consecutive patients undergoing RARP with the SP robot were matched, using a propensity score (PS), with 100 patients from a cohort of 1757 who were operated on with the da Vinci Xi from June 2019 to January 2021. We described and compared the perioperative pain scores and outcomes of both groups. The SP group had less blood loss (50 cc vs. 62.5 cc, P < 0.001) and longer operative time (114 min. vs. 94 min, P < 0.001). The only period we could show a difference in postoperative pain scores was 6 h after surgery, with a small advantage for the SP (2 vs. 2.5, P < 0.001). Both groups had satisfactory postoperative continence recovery, 91% vs. 90% for the SP and Xi, respectively. The groups had a mean follow-up of 24.5 and 22 months for SP and Xi, respectively. The tumor stage and percentage of positive surgical margins were similar between groups (15% vs. 15%, P = 1). Patients undergoing RARP with the SP had longer operative times with less blood loss than the Xi. However, despite the lower number of abdominal incisions on the SP, the groups had similar intraoperative performance, and we were unable to demonstrate clinically significant differences in postoperative pain scores between the groups 6, 12, and 18 h after surgery.


Assuntos
Laparoscopia , Procedimentos Cirúrgicos Robóticos , Robótica , Masculino , Humanos , Procedimentos Cirúrgicos Robóticos/métodos , Prostatectomia/métodos , Laparoscopia/métodos , Dor Pós-Operatória/prevenção & controle , Resultado do Tratamento
19.
Urolithiasis ; 51(1): 27, 2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36596939

RESUMO

The incidence of nephrolithiasis is rising worldwide. Although it is a multifactorial disease, lifestyle plays a major role in its etiology. Another considerable factor could be an aberrant microbiome. In our observational single-center study, we aimed to investigate the composition of bacteria in kidney stones and urine focusing on patients with features of metabolic syndrome. Catheterized urine and kidney stones were collected prospectively from 100 consecutive patients undergoing endoscopic nephrolithotomy between 2020 and 2021 at our clinic. Microbiome composition was analyzed via 16S rRNA gene amplicon sequencing. Detection of bacteria was successful in 24% of the analyzed kidney stones. These patients had a prolonged length of stay compared to patients without verifiable bacteria in their stones (2.9 vs 1.5 days). Patients with features of metabolic syndrome were characterized by kidney stones colonized with classical gastrointestinal bacteria and displayed a significant enrichment of Enterococcaceae and Enterobacteriaceae. Stones of patients without features of metabolic syndrome characterized by Ureaplasma and Staphylococcaceae. Patients with bacteria in their kidney stones exhibit a longer length of stay, possibly due to more complex care. Patients presenting with features of metabolic syndrome displayed a distinct stone microbiome compared to metabolically fit patients. Understanding the role of bacteria in stone formation could enable targeted therapy, prevention of post-operative complications and new therapeutic strategies.


Assuntos
Cálculos Renais , Síndrome Metabólica , Microbiota , Nefrolitíase , Humanos , RNA Ribossômico 16S/genética , Cálculos Renais/diagnóstico , Nefrolitíase/urina , Bactérias
20.
Front Plant Sci ; 14: 1024981, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37324717

RESUMO

Cyanobacteria are a promising platform for the production of the triterpene squalene (C30), a precursor for all plant and animal sterols, and a highly attractive intermediate towards triterpenoids, a large group of secondary plant metabolites. Synechocystis sp. PCC 6803 natively produces squalene from CO2 through the MEP pathway. Based on the predictions of a constraint-based metabolic model, we took a systematic overexpression approach to quantify native Synechocystis gene's impact on squalene production in a squalene-hopene cyclase gene knock-out strain (Δshc). Our in silico analysis revealed an increased flux through the Calvin-Benson-Bassham cycle in the Δshc mutant compared to the wildtype, including the pentose phosphate pathway, as well as lower glycolysis, while the tricarboxylic acid cycle predicted to be downregulated. Further, all enzymes of the MEP pathway and terpenoid synthesis, as well as enzymes from the central carbon metabolism, Gap2, Tpi and PyrK, were predicted to positively contribute to squalene production upon their overexpression. Each identified target gene was integrated into the genome of Synechocystis Δshc under the control of the rhamnose-inducible promoter Prha. Squalene production was increased in an inducer concentration dependent manner through the overexpression of most predicted genes, which are genes of the MEP pathway, ispH, ispE, and idi, leading to the greatest improvements. Moreover, we were able to overexpress the native squalene synthase gene (sqs) in Synechocystis Δshc, which reached the highest production titer of 13.72 mg l-1 reported for squalene in Synechocystis sp. PCC 6803 so far, thereby providing a promising and sustainable platform for triterpene production.

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