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Herbicides are useful tools for managing weeds and promoting food production and sustainable agriculture. In this study, we report on the development of a novel class of lipophilic pyrimidine-biphenyl (PMB) herbicides. Firstly, three PMBs, Ia, IIa, and IIIa, were rationally designed via a scaffold hopping strategy and were determined to inhibit acetohydroxyacid synthase (AHAS). Computational simulation was carried out to investigate the molecular basis for the efficiency of PMBs against AHAS. With a rational binding mode, and the highest in vitro as well as in vivo potency, Ia was identified as a preferable hit. Furthermore, these integrated analyses guided the design of eighteen new PMBs, which were synthesized via a one-step Suzuki-Miyaura cross-coupling reaction. These new PMBs, Iba-ic, were more effective in post-emergence control of grass weeds compared with Ia. Interestingly, six of the PMBs displayed 98-100% inhibition in the control of grass weeds at 750 g ai/ha. Remarkably, Ica exhibited ≥ 80% control against grass weeds at 187.5 g ai/ha. Overall, our comprehensive and systematic investigation revealed that a structurally distinct class of lipophilic PMB herbicides, which pair excellent herbicidal activities with new interactions with AHAS, represent a noteworthy development in the pursuit of sustainable weed control solutions.
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Herbicidas , Pirimidinas , Herbicidas/química , Herbicidas/farmacologia , Pirimidinas/química , Pirimidinas/farmacologia , Acetolactato Sintase/antagonistas & inibidores , Acetolactato Sintase/metabolismo , Acetolactato Sintase/química , Compostos de Bifenilo/química , Compostos de Bifenilo/antagonistas & inibidores , Simulação de Acoplamento Molecular , Plantas Daninhas/efeitos dos fármacos , Relação Estrutura-Atividade , Estrutura MolecularRESUMO
Very-long-chain alkane plays an important role as an aliphatic barrier. We previously reported that BnCER1-2 was responsible for alkane biosynthesis in Brassica napus and improved plant tolerance to drought. However, how the expression of BnCER1-2 is regulated is still unknown. Through yeast one-hybrid screening, we identified a transcriptional regulator of BnCER1-2, BnaC9.DEWAX1, which encodes AP2\ERF transcription factor. BnaC9.DEWAX1 targets the nucleus and displays transcriptional repression activity. Electrophoretic mobility shift and transient transcriptional assays suggested that BnaC9.DEWAX1 repressed the transcription of BnCER1-2 by directly interacting with its promoter. BnaC9.DEWAX1 was expressed predominantly in leaves and siliques, which was similar to the expression pattern of BnCER1-2. Hormone and major abiotic stresses such as drought and high salinity affected the expression of BnaC9.DEWAX1. Ectopic expression of BnaC9.DEWAX1 in Arabidopsis plants down-regulated CER1 transcription levels and resulted in a reduction in alkanes and total wax loads in leaves and stems when compared with the wild type, whereas the wax depositions in the dewax mutant returned to the wild type level after complementation of BnaC9.DEWAX1 in the mutant. Moreover, both altered cuticular wax composition and structure contribute to increased epidermal permeability in BnaC9.DEWAX1 overexpression lines. Collectively, these results support the notion that BnaC9.DEWAX1 negatively regulates wax biosynthesis by binding directly to the BnCER1-2 promoter, which provides insights into the regulatory mechanism of wax biosynthesis in B. napus.
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Brassica napus , Proteínas de Plantas , Alcanos/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Brassica napus/genética , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Folhas de Planta/metabolismo , Ceras/metabolismoRESUMO
Vibrio parahaemolyticus is usually spread via consumption of contaminated seafood and causes vibriosis. By combination of digital microfluidic (DMF) and loop-mediated isothermal amplification (LAMP), we provided an automated instrumentation-compact DMF-LAMP device for sample-to-answer detection of V. parahaemolyticus. For the first time, how much the proper mixing might facilitate the DMF-LAMP process is explored. The results illustrated that increasing the number of flow configurations and decreasing the fluid-reversibility will extend the interfacial surface available for diffusion-based mass transfer within a droplet microreactor, thus contributing to the overall amplification reaction rate. Noticeably, the DMF-LAMP amplification plateau time is shortened by proper mixing, from 60 min in static mixing and traditional bulk LAMP to 30 min in 2-electrode mixing and 15 min in 3-electrode mixing. The device achieved much higher detection sensitivity (two copies per reaction) than previously reported devices. V. parahaemolyticus from spiked shrimps is detected by Q-tip sampling associated with 3-electrode mixing DMF-LAMPs. The detectable signal occurs within only 3 min at a higher concentration and, at most, is delayed to 18 min, with a detection limit of <0.23 × 103 CFU/g. Thus, the developed DMF-LAMP device demonstrates potential for being used as a sample-to-answer system with a quick analysis time, high sensitivity, and sample-to-answer format.
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Vibrio parahaemolyticus , Microfluídica , Técnicas de Diagnóstico Molecular , Técnicas de Amplificação de Ácido Nucleico , Vibrio parahaemolyticus/genéticaRESUMO
Algae are the promising feedstock of biofuel. The screening of competent species and proper fertilizer supply is of the most important tasks. To accelerate this rather slow and laborious step, we developed an integrated high-throughput digital microfluidic (DMF) system that uses a discrete droplet to serve as a microbioreactor, encapsulating microalgal cells. On the basis of fundamental understanding of various droplet hydrodynamics induced by the existence of different sorts of ions and biological species, incorporation of capacitance-based position estimator, electrode-saving-based compensation, and deterministic splitting approach, was performed to optimize the DMF bioreactor. Thus, it enables all processes (e.g., nutrient gradient generation, algae culturing, and analyzing of growth and lipid accumulation) occurring automatically on-chip especially in a high-fidelity way. The ability of the system to compare different microalgal strains on-chip was investigated. Also, the Chlorella sp. were stressed by various conditions and then growth and oil accumulation were analyzed and compared, which demonstrated its potential as a powerful tool to investigate microalgal lipid accumulation at significantly lower laborites and reduced time.
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Biomassa , Reatores Biológicos , Dispositivos Lab-On-A-Chip , Lipídeos/biossíntese , Microalgas/crescimento & desenvolvimento , Técnicas Analíticas Microfluídicas , Estresse FisiológicoRESUMO
Here, we present the rational design of a pinwheel-shaped three-dimensional microfluidic paper-based analytical device (3D-µPAD) for specific, sensitive and multiplexed detection of heavy metals in coastal waters. A more homogeneous permeation of fluids along the chip than common design, even under unskilled performance, has been achieved by the elaborate chip design of the hydrostatic balancing inlet port and uniformly stressed reversible sealing. With the combination of ion imprinted polymer grafted CdTe quantum-dots and fluid accumulation pad, 4 metals (Cu2+, Cd2+, Pb2+, and Hg2+) in 1 analysis and 25-fold enrichment for each metal can be simultaneously performed within 20 min, with detection limits of 0.007-0.015 µg/L. It has the ability to selectively recognize these 4 metals in mixtures and immunizing to interferences from components found in coastal waters, which provided results that were in agreement with values gained from atomic absorption. The inexpensive and portable nature as well as the highly sensitive and flexible performance of the new developed 3D-µPAD could make it attractive as an on-site testing approach for marine environmental monitoring.
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BACKGROUND: Brassica napus L. is one of the most important oil crops in the world. However, climate-change-induced environmental stresses negatively impact on its yield and quality. Cuticular waxes are known to protect plants from various abiotic/biotic stresses. Dissecting the genetic and biochemical basis underlying cuticular waxes is important to breed cultivars with improved stress tolerance. RESULTS: Here a genome-wide association study (GWAS) of 192 B. napus cultivars and inbred lines was used to identify single-nucleotide polymorphisms (SNPs) associated with leaf waxes. A total of 202 SNPs was found to be significantly associated with 31 wax traits including total wax coverage and the amounts of wax classes and wax compounds. Next, epidermal peels from leaves of both high-wax load (HW) and low-wax load (LW) lines were isolated and used to analyze transcript profiles of all GWAS-identified genes. Consequently, 147 SNPs were revealed to have differential expressions between HW and LW lines, among which 344 SNP corresponding genes exhibited up-regulated while 448 exhibited down-regulated expressions in LW when compared to those in HW. According to the gene annotation information, some differentially expressed genes were classified into plant acyl lipid metabolism, including fatty acid-related pathways, wax and cutin biosynthesis pathway and wax secretion. Some genes involved in cell wall formation and stress responses have also been identified. CONCLUSIONS: Combination of GWAS with transcriptomic analysis revealed a number of directly or indirectly wax-related genes and their associated SNPs. These results could provide clues for further validation of SNPs for marker-assisted breeding and provide new insights into the genetic control of wax biosynthesis and improving stress tolerance of B. napus.
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Brassica napus/genética , Genes de Plantas , Epiderme Vegetal/genética , Folhas de Planta/genética , Ceras/metabolismo , Brassica napus/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Estudo de Associação Genômica Ampla , Fenótipo , Epiderme Vegetal/metabolismo , Folhas de Planta/metabolismo , Polimorfismo de Nucleotídeo Único , RNA de Plantas , RNA-SeqRESUMO
This paper combined experiments with a theoretical model to simulate the behavior between a foam and heavy oil during contact pressing, separation, and adsorption. We discuss the changes in the elasticity and adsorption forces during the pressing and adsorption of the two fluids. The influence of the changes in temperature and pressure, the concentration of the sodium dodecyl sulfate surfactant, the heavy oil viscosity, and the addition of partially hydrolyzed polyacrylamide and hydrophobic SiO2 nanoparticles was studied. The results showed that the overall increase in the elasticity and adsorption forces between the foam at 1 wt % surfactant and heavy oil was more than 2 times greater than those of the foam with 0.2 wt % surfactant. The increase in viscosity of heavy oil also increased various forces. The overall improvement in the adsorption force between fluids caused by nanoparticles during separation and adsorption stages reached 1.8 times, which was better than that obtained using the polymer (1.65 times). However, the polymer showed a 1.4 times higher elastic force during the fluid pressing stage than the nanoparticles and about 4 times higher than the control foam, and the increase in temperature greatly weakened the effect of the force, while the change in pressure did not cause much impact. An analytical model was built based on fluid mechanics, and the calculation results were consistent with the experimental data with an error of about 5-12%, suggesting that this model provides a good reference value.
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Given the prevalence of the malignant weed Chinese Sprangletop (Leptochloa chinensis (L.) Nees) in rice fields, the development of novel herbicides against this weed has aroused wide interest. Here, we report a novel diphenyl ether-pyrimidine hybrid, DEP-5, serving as a systematic pre/postemergence herbicide candidate for broad-spectrum weed control in rice fields, specifically for L. chinensis. Notably, DEP-5 exhibits over 80% herbicidal activity against the resistant biotypes even at 37.5 g a.i./ha under greenhouse conditions and has complete control of L. chinensis at 150 g a.i./ha in the rice fields. We uncover that DEP-5 acts as a noncompetitive inhibitor of acetohydroxyacid synthase (AHAS) with an inhibition constant (Ki) of 39.4 µM. We propose that DEP-5 binds to AHAS in two hydrophobic-driven binding modes that differ from commercial AHAS inhibitors. Overall, these findings demonstrate that DEP-5 has great potential to be developed into a herbicide for L. chinensis control and inspire fresh concepts for novel AHAS-inhibiting herbicide design.
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Acetolactato Sintase , Herbicidas , Oryza , Proteínas de Plantas , Plantas Daninhas , Poaceae , Controle de Plantas Daninhas , Herbicidas/farmacologia , Herbicidas/química , Oryza/química , Plantas Daninhas/efeitos dos fármacos , Plantas Daninhas/enzimologia , Acetolactato Sintase/metabolismo , Acetolactato Sintase/antagonistas & inibidores , Acetolactato Sintase/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/antagonistas & inibidores , Poaceae/química , Poaceae/enzimologia , Poaceae/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Pirimidinas/farmacologia , Cinética , Éteres Fenílicos/farmacologia , Éteres Fenílicos/químicaRESUMO
The increasing demand for dairy products has led to the production of a large amount of wastewater in dairy plants, and disinfection is an essential treatment process before wastewater discharge. Disinfection byproducts (DBPs) in disinfected dairy wastewater may negatively influence the aquatic organisms in receiving water. During chlorine and chloramine disinfection of dairy wastewater, the concentrations of aliphatic DBPs increased from below the detection limits to 485.1 µg/L and 26.6 µg/L, respectively. Brominated and iodinated phenolic DBPs produced during chlor(am)ination could further react with chlorine/chloramine to be transformed. High level of bromide in dairy wastewater (12.9 mg/L) could be oxidized to active bromine species by chlorine/chloramine, promoting the formation of highly toxic brominated DBPs (Br-DBPs), and they accounted for 80.3% and 71.1% of the total content of DBPs in chlorinated and chloraminated dairy wastewater, respectively. Moreover, Br-DBPs contributed 49.9-75.9% and 34.2-96.4% to the cumulative risk quotient of DBPs in chlorinated and chloraminated wastewater, respectively. The cumulative risk quotient of DBPs on green algae, daphnid, and fish in chlorinated wastewater was 2.8-11.4 times higher than that in chloraminated wastewater. Shortening disinfection time or adopting chloramine disinfection can reduce the ecological risks of DBPs.
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Desinfetantes , Poluentes Químicos da Água , Purificação da Água , Animais , Desinfecção , Cloraminas , Águas Residuárias , Cloro , Halogenação , Poluentes Químicos da Água/análiseRESUMO
The hydraulic performance of single-wing labyrinth drip irrigation tapes under the coupling effect of water and fertilizer affects the operating efficiency of the entire drip irrigation system. In this study, three types of single-wing labyrinth drip irrigation tapes were studied. We evaluated the average relative flow of each type and conducted indoor uniform orthogonal tests of three factors, namely, fertilizer concentration, sediment content, and operating pressure. The results showed that the order of the factors affecting the average relative flow of single-wing labyrinth drip irrigation tape was sediment content > fertilizer concentration > operating pressure. The projection pursuit regression (PPR) models of the average relative flow of three types of single-wing labyrinth drip irrigation tapes (H1, H2, and H3) were established. The root mean square errors (nRMSE) of these three models were 0.66%, 0.74%, 0.34%, respectively, indicating their excellent prediction performance. The optimal performance of the three types of tapes were obtained when the fertilizer concentration was 0.6 g/L, the sediment content was 1 g/L, and the operating pressure was 40 kPa. Under the optimal condition, the average relative flows of H1-type, H2-type, and H3-type were 0.792, 0.764, and 0.700, respectively.
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Approximately 70% steam-assisted gravity drainage (SAGD) wellpairs have entered into the production phase in China, while due to the fluvial sedimentation environment with strong reservoir heterogeneity, only 53% of the horizontal well section develops a steam chamber. In order to massively recover the bypassed oil and expand the steam chamber along the horizontal section, downhole electrical heating was proposed, and its mechanisms of high temperature-induced rock mechanics change and influence factors are investigated in this study using laboratory experiments and electrical steam hybrid numerical simulation. It is found that the electrical heating-assisted SAGD has four key mechanisms, namely, localized temperature elevation, development of a fixed point steam chamber, localized oil gravity drainage, and petrophysical property improvement. The influence factors include the static and operational factors, in which the permeability ratio is the primary factor for choosing SAGD wellpairs, while the steam injection rate, steam chamber operational pressure, injector and producer pressure difference, adjacent SAGD steam chamber pressure differential, heater surface temperature, and electrical heating period integrally influence the incremental production performance. Through carefully modifying the parameters, the typical SAGD wellpair steam chamber could expand from 67 to 100% along the horizontal section, with an incremental oil rate of 3-5 m3/day, and the cumulative steam/oil ratio decreases from 6.67 to 4.17. The downhole electrical heating is particularly efficient in improving steam chamber conformance in heterogeneous reservoirs and also has significant potential in similar reservoirs developed by horizontal wells.
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Two new compounds, compounds 1 and 2, were obtained from the culture of a marine-derived fungus Talaromyces sp. MCCC 3A01752, together with 13 known compounds (3-15). Their structures were elucidated based on detailed analysis of NMR, HRESIMS, ECD spectra and OR value. Compound 1 exhibited antibacterial potential against Staphylococcus aureus with a MIC value of 100 µM and cytotoxic activity against gastric cancer cell line MKN1 with a IC50 value of 78.0 µM.
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The N-glycosylation pathway in Pichia pastoris has been humanized by the deletion of genes responsible for fungal-type glycosylation (high mannose) as well as the introduction of heterologous genes capable of forming human-like N-glycosylation. This results in a yeast host that is capable of expressing therapeutic glycoproteins. A thorough investigation was performed to examine whether glycoproteins expressed in glycoengineered P. pastoris strains may contain residual fungal-type high-mannose structures. In a pool of N-linked glycans enzymatically released by protein N-glycosidase from a reporter glycoprotein expressed in a developmental glycoengineered P. pastoris strain, an oligosaccharide with a mass consistent with a Hexose(9)GlcNAc(2) oligosaccharide was identified. When this structure was analyzed by a normal-phase high-performance liquid chromatography (HPLC), its retention time was identical to a Man(9)GlcNAc(2) standard. However, this Hexose(9)GlcNAc(2) oligosaccharide was found to be resistant to α-1,2-mannosidase as well as endomannosidase, which preferentially catabolizes endoplasmic reticulum oligosaccharides containing terminal α-linked glucose. To further characterize this oligosaccharide, we purified the Hexose(9)GlcNAc(2) oligosaccharide by HPLC and analyzed the structure by high-field one-dimensional (1D) and two-dimensional (2D) (1)H NMR (nuclear magnetic resonance) spectroscopy followed by structural elucidation by homonuclear and heteronuclear 1D and 2D (1)H and (13)C NMR spectroscopy. The results of these experiments lead to the identification of an oligosaccharide α-Man-(1 â 2)-ß-Man-(1 â 2)-ß-Man-(1 â 2)-α-Man-(1 â 2) moiety as part of a tri-antennary structure. The difference in enzymatic reactivity can be attributed to multiple ß-linkages on the α-1,3 arm of the Man(9)GlcNAc(2) oligosaccharide.
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Manosidases/metabolismo , Proteínas de Membrana/metabolismo , Oligossacarídeos/biossíntese , Oligossacarídeos/química , Pichia/metabolismo , Humanos , Manosidases/genética , Proteínas de Membrana/genética , Pichia/genética , Conformação Proteica , Relação Estrutura-AtividadeRESUMO
A robust and scalable purification process was developed to quickly generate antibody of high purity and sufficient quantity from glycoengineered Pichia pastoris fermentation. Protein A affinity chromatography was used to capture the antibody from fermentation supernatant. A pH gradient elution was applied to the Protein A column to prevent antibody precipitation at low pH. Antibody from Protein A chromatography contained some product related impurities, which were the misassembling of cleaved heavy chain, heavy chain and light chain. It also had some process related impurities, including Protein A residues, endotoxin, host cell DNA and proteins. Cation exchange chromatography with optimal NaCl gradient at pH 4.5-6.0 efficiently removed these product and process related impurities. The antibody from glycoengineered P. pastoris was comparable to its commercial counterpart in heterotetramer folding, physical stability and binding affinity.
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Anticorpos Monoclonais/biossíntese , Pichia/metabolismo , Proteínas Recombinantes/biossíntese , Anticorpos Monoclonais/isolamento & purificação , Organismos Geneticamente Modificados , Pichia/genética , Proteínas Recombinantes/isolamento & purificaçãoRESUMO
Heavy oil emulsions such as water in oil (W/O), oil in water (O/W), and water in oil in water (W/O/W) would be formed during the development of heavy oil reservoirs. The key to the efficient development of heavy oil reservoirs is to clarify the fluidity of heavy oil emulsions in formation pores medium. In this study, the main factors that determine the fluidity of heavy oil emulsion were analyzed under the condition of simulating the formation pores medium. The reasons for the difference between the viscosity of heavy oil emulsions in formation pores medium and the viscosity measured by laboratory rheometer were analyzed. Then, experiments have confirmed the shortcomings of the current screening and evaluation method of emulsified viscosity reducer. Finally, through experimental research and mechanism analysis, the mechanism of the emulsified viscosity reducer was studied and suggestions were made to improve the effect of emulsified viscosity reducer in the oil field. When heavy emulsions flow in a formation pores medium, since the size of the droplets would be larger than the size of the pores medium, when the heavy emulsion passes through the pores medium, it would receive additional resistance brought by the Jiamin effect. But when a rheometer is used for viscosity testing, this additional resistance is almost nonexistent. Therefore, the current method of viscosity test using rheometer cannot fully reflect the actual flow state of heavy oil emulsion in formation pores medium. The research in this paper proves that the larger the droplets of the emulsion, the less accurate the rheometer test results. Temperature, permeability, oil-water ratio, and the type of emulsified viscosity reducer all have a certain effect on the flow of heavy oil emulsion in formation pores medium. This article evaluated four types of emulsified viscosity reducers. When the viscosity test was performed by a rheometer, the results showed excellent viscosity-reducing effects. However, when simulating formation pores medium conditions, the effects of some types of emulsified viscosity reducers are not so good. It is no longer accurate to judge the effect of emulsified viscosity reducer by the way of measuring viscosity with a rheometer. It should be screened by the flow capacity of the heavy oil emulsions in formation pores medium. In oil field development, the contact area of heavy oil and emulsified viscosity reducer solution should be increased as much as possible and provide more time for the substitution effect of emulsified viscosity reducer molecules.
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Two-dimensional digital microfluidic platforms, on which droplets are actuated by electrowetting on dielectrics, have merits such as dynamic reconfigurability and ease for automation. However, concerns for digital microfluidic platforms based on low-cost printed circuit boards, such as the scalability of the electrode array and the reliability of the device operation, should be addressed before high throughput and fully automatic applications can be realized. In this work we report the progress in addressing those issues by using active-matrix circuitry to automatically drive a large electrode array with enhanced device reliability. We describe the design and the fabrication of a robust and scalable active-matrix driven digital microfluidic platform based on printed-circuit board technology. Reliable actuation of aqueous and organic droplets is achieved using a free-standing double-layer hydrophobic membrane. To demonstrate the versatility of the digital microfluidic platform, a pentapeptide is synthesized on the device within 30 minutes. With these improvements, a fully automatic, scalable, robust, reusable, and low-cost digital microfluidic platform capable of parallel manipulation of a large number of droplets can find numerous applications in chemical engineering, bioengineering and biomedical engineering.
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Bispecific antibodies (bsAb) that target two independent epitopes or antigens have been extensively explored in translational and clinical studies since they were first developed in the 1960s. Many bsAbs are being tested in clinical trials for treating a variety of diseases, mostly cancer. Here, we provide an overview of various types of bsAbs in clinical studies and discuss their targets, safety profiles, and efficacy. We also highlight the current challenges, potential solutions, and future directions of bsAb development for cancer treatment.
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Anticorpos Biespecíficos , Neoplasias , Anticorpos Biespecíficos/uso terapêutico , Antígenos , Humanos , Neoplasias/tratamento farmacológicoRESUMO
Glycoengineered Pichia pastoris provides a unique platform for screening monoclonal antibody (mAb) leads and high expressing strains. A simple, economic, and high-throughput purification for mAb from P. pastoris fermentation has been developed that can be easily operated in various commercially available liquid handlers. The method includes the use of STREAMLINE rProtein A in a 96-well platform and demonstrates good linear alignment and reproducibility in a wide concentration range. The antibody titers measured by the method have less than 15% variation in comparison to spiking titers. The mAb titer and quality obtained from this method are comparable to that from conventional column chromatography. The method can process hundreds of expression screening samples in a day, not only to accurately determine titers, but also to generate milligram quantities of mAb for quality assessment, including purity, folding, glycosylation, and antigen binding affinity.
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Anticorpos Monoclonais/isolamento & purificação , Fermentação , Microbiologia Industrial/métodos , Pichia/genética , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/metabolismo , Cromatografia Líquida de Alta Pressão/economia , Cromatografia Líquida de Alta Pressão/métodos , Expressão Gênica , Glicosilação , Imunoglobulina G/genética , Imunoglobulina G/isolamento & purificação , Imunoglobulina G/metabolismo , Microbiologia Industrial/economia , Reprodutibilidade dos Testes , Proteína Estafilocócica A/metabolismoRESUMO
The methylotrophic yeast Pichia pastoris has recently been engineered to express therapeutic glycoproteins with uniform human N-glycans at high titers. In contrast to the current art where producing therapeutic proteins in mammalian cell lines yields a final product with heterogeneous N-glycans, proteins expressed in glycoengineered P. pastoris can be designed to carry a specific, preselected glycoform. However, significant variability exists in fermentation performance between genotypically similar clones with respect to cell fitness, secreted protein titer, and glycan homogeneity. Here, we describe a novel, multidimensional screening process that combines high and medium throughput tools to identify cell lines producing monoclonal antibodies (mAbs). These cell lines must satisfy multiple selection criteria (high titer, uniform N-glycans and cell robustness) and be compatible with our large-scale production platform process. Using this selection process, we were able to isolate a mAb-expressing strain yielding a titer (after protein A purification) in excess of 1 g/l in 0.5-l bioreactors.
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Anticorpos Monoclonais/biossíntese , Engenharia Genética , Glicoproteínas/biossíntese , Pichia/isolamento & purificação , Proteínas Recombinantes/biossíntese , Anticorpos Monoclonais/genética , Reatores Biológicos , Técnicas de Cultura de Células , Linhagem Celular , DNA Fúngico/genética , Fermentação , Expressão Gênica , Glicoproteínas/genética , Glicosilação , Humanos , Técnicas Microbiológicas , Pichia/genética , Pichia/metabolismo , Proteínas Recombinantes/genética , Seleção Genética , Transformação GenéticaRESUMO
BACKGROUND: Cuticular waxes cover plant surface and play important roles in protecting plants from abiotic and biotic stresses. The variations of wax deposition and chemical compositions under changing environments have been shown to be related to plant adaptations. However, it is still not clear whether the wax depositions could be adjusted to increase plant adaptations to stressed conditions. METHODS: In this study, exogenous methyl jasmonate (MeJA), the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) and salicylic acid (SA) were applied to test their effects on cuticular wax deposition in two Brassica napus cultivars, Zhongshuang 9 (ZS9, low wax coverage ) and Yuyou 19 (YY19, high wax coverage). Next, we measured the water loss rate and the transcriptional expression of genes involved in wax biosynthesis as well as genes related to disease defense. RESULTS: Seven wax compound classes, including fatty acids, aldehydes, alkanes, secondary alcohols, ketones, and unbranched as well as branched primary alcohols, were identified in B. napus leaf wax mixtures. MeJA, SA and ACC treatments had no significant effect on total wax amounts in YY19, whereas ACC reduced total wax amounts in ZS9. Overall, hormone treatments led to an increase in the amounts of aldehydes and ketones, and a decrease of secondary alcohol in ZS9, whereas they led to a decrease of alkane amounts and an increase of secondary alcohol amounts in YY19. Concomitantly, both cultivars also exhibited different changes in cuticle permeability, with leaf water loss rate per 15 min increased from 1.57% (averaged across treatments) at 1.57% (averaged across treatments) at 15 min to 3.12% at 30 min for ZS9 (except for ACC treated plant) and decreased for YY19. MeJA-treated plants of both cultivars relatively had higher water loss rate per 15 min when compared to other treatments. Conclusion. Our findings that B. napus leaf wax composition and cuticle permeability are altered by exogenous SA, MeJA and ACC suggest that the hormone treatments affect wax composition, and that the changes in wax profiles would cause changes in cuticle permeability.