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Boghigian BA Myint M Wu J Pfeifer BA 《Journal of industrial microbiology & biotechnology》2011,38(11):1809-1820
Natural products have long served as rich sources of drugs possessing a wide range of pharmacological activities. The discovery
and development of natural product drug candidates is often hampered by the inability to efficiently scale and produce a molecule
of interest, due to inherent qualities of the native producer. Heterologous biosynthesis in an engineering and process-friendly
host emerged as an option to produce complex natural products. Escherichia coli has previously been utilized to produce complex precursors to two popular natural product drugs, erythromycin and paclitaxel.
These two molecules represent two of the largest classes of natural products, polyketides and isoprenoids, respectively. In
this study, we have developed a platform E. coli strain capable of simultaneous production of both product precursors at titers greater than 15 mg l−1. The utilization of a two-phase batch bioreactor allowed for very strong in situ separation (having a partitioning coefficient
of greater than 5,000), which would facilitate downstream purification processes. The system developed here could also be
used in metagenomic studies to screen environmental DNA for natural product discovery and preliminary production experiments. 相似文献
504.
Dong-Hoon Lee Diana A Tran Purnima Singh Nathan Oates Guillermo E Rivas Garrett P Larson Gerd P Pfeifer Piroska E Szabó 《Epigenetics》2011,6(2):212-223
5-methyl-C (5mC) and 5-hydroxymethyl-C (5hmC) are epigenetic marks with well-known and putative roles in gene regulation, respectively. These two DNA covalent modifications cannot be distinguished by bisulfite sequencing or restriction digestion, the standard methods of 5mC detection. The methylated CpG island recovery assay (MIRA), however, specifically detects 5mC but not 5hmC. We further developed MIRA for the analysis of allele-specific CpG methylation at differentially methylated regions (DMRs) of imprinted genes. MIRA specifically distinguished between the parental alleles by capturing the paternally methylated H19/Igf2 DMR and maternally methylated KvDMR1 in mouse embryo fibroblasts (MEFs) carrying paternal and maternal duplication of mouse distal Chr7, respectively. MIRA in combination with multiplex single nucleotide primer extension (SNuPE) assays specifically captured the methylated parental allele from normal cells at a set of maternally and paternally methylated DMRs. The assay correctly recognized aberrant biallelic methylation in a case of loss of imprinting. The MIRA-SNuPE assays revealed that placenta exhibited less DNA methylation bias at DMRs compared to yolk sac, amnion, brain, heart, kidney, liver and muscle. This method should be useful for the analysis of allele-specific methylation events related to genomic imprinting, X chromosome inactivation and for verifying and screening haplotype-associated methylation differences in the human population.Key words: epigenetics, imprinting, DMR, MIRA, MBD, DNA methylation, SNuPE 相似文献
505.
Hugo Gravato Marques Farhan Imtiaz Fumiya Iida Rolf Pfeifer 《Biological cybernetics》2013,107(1):25-37
In mammals, the development of reflexes is often regarded as an innate process. However, recent findings show that fetuses are endowed with favorable conditions for ontogenetic development. In this article, we hypothesize that the circuitry of at least some mammalian reflexes can be self-organized from the sensory and motor interactions brought forth in a musculoskeletal system. We focus mainly on three reflexes: the myotatic reflex, the reciprocal inhibition reflex, and the reverse myotatic reflex. To test our hypothesis, we conducted a set of experiments on a simulated musculoskeletal system using pairs of agonist and antagonist muscles. The reflex connectivity is obtained by producing spontaneous motor activity in each muscle and by correlating the resulting sensor and motor signals. Our results show that, under biologically plausible conditions, the reflex circuitry thus obtained is consistent with that identified in relation to the analogous mammalian reflexes. In addition, they show that the reflex connectivity obtained depends on the morphology of the musculoskeletal system as well as on the environment that it is embedded in. 相似文献
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T A Pfeifer M M Guarna E M Kwan G Lesnicki D A Theilmann T A Grigliatti D G Kilburn 《Protein expression and purification》2001,23(2):233-241
A modified Factor X protein was combined with a cellulose-binding domain tag and expressed in insect cell lines. The protein, CBDFX, was expressed and secreted into the medium. Stable, transformed Hi5 and Sf9 insect cell lines were generated and tested for production of secreted CBDFX. The highest Sf9 and Hi5 CBDFX-producing cell lines were scaled up to 2-liter fermentors to evaluate production of this recombinant protein. Secreted protein production levels reached 4 mg/liter for the stable, transformed Hi5 cell line and 18 mg/liter for the stable, transformed Sf9 cell line. The protein was properly processed as determined by amino terminal sequencing and bound well to the cellulose substrate Avicel. In addition the activated recombinant CBDFX(a) was capable of recognizing and efficiently processing a Factor X cleavage site. 相似文献
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Impact of Helicopter Emergency Medical Service in Traumatized Patients: Which Patient Benefits Most?
Hagen Andruszkow Uwe Schweigkofler Rolf Lefering Magnus Frey Klemens Horst Roman Pfeifer Stefan Kurt Beckers Hans-Christoph Pape Frank Hildebrand 《PloS one》2016,11(1)
Introduction
The Helicopter Emergency Medical Service (HEMS) was established for the prehospital trauma care of patients. Improved rescue times and increased coverage areas are discussed as specific advantages of HEMS. We recently found evidence that HEMS exerts beneficial effects on outcomes for severely injured patients. However, it still remains unknown which group of trauma patients might benefit most from HEMS rescue. Consequently, the unique aim of this study was to reveal which patients might benefit most from HEMS rescue.Methods
Trauma patients (ISS ≥9) primarily treated by HEMS or ground emergency medical services (GEMS) between 2002 and 2012 were analysed using the TraumaRegister DGU. A multivariate regression analysis was used to reveal the survival benefit between different trauma populations.Results
The study included 52 281 trauma patients. Of these, 68.8% (35 974) were rescued by GEMS and 31.2% (16 307) by HEMS. HEMS patients were more severely injured compared to GEMS patients (ISS: HEMS 24.8±13.5 vs. GEMS 21.7±18.0) and more frequently suffered traumatic shock (SBP sys <90mmHg: HEMS 18.3% vs. GEMS 14.8%). However, logistic regression analysis revealed that HEMS rescues resulted in an overall survival benefit compared to GEMS (OR 0.81, 95% CI [0.75–0.87], p<0.001, Nagelkerke''s R squared 0.526, area under the ROC curve 0.922, 95% CI [0.919–0.925]). Analysis of specific subgroups demonstrated that patients aged older than 55 years (OR 0.62, 95% CI [0.50–0.77]) had the highest survival benefit after HEMS treatment. Furthermore, HEMS rescue had the most significant impact after ‘low falls’ (OR 0.68, 95% CI [0.55–0.84]) and in the case of minor severity injuries (ISS 9–15) (OR 0.66, 95% CI [0.49–0.88]).Conclusions
In general, trauma patients benefit from HEMS rescue with in-hospital survival as the main outcome parameter. Focusing on special subgroups, middle aged and older patients, low-energy trauma, and minor severity injuries had the highest survival benefit when rescued by HEMS. Further studies are required to determine the potential reasons of this benefit. 相似文献510.
Norman BH Richardson TI Dodge JA Pfeifer LA Durst GL Wang Y Durbin JD Krishnan V Dinn SR Liu S Reilly JE Ryter KT 《Bioorganic & medicinal chemistry letters》2007,17(18):5082-5085
Benzopyrans are selective estrogen receptor (ER) beta agonists (SERBAs), which bind the ER receptor subtypes alpha and beta in opposite orientations. We have used structure based drug design to show that this unique phenomena can be exploited via substitution at the 8-position of the benzopyran A-ring to disrupt binding to ERalpha, thus improving ERbeta subtype selectivity. X-ray cocrystal structures with ERalpha and ERbeta are supportive of this approach to improve selectivity in this structural class. 相似文献