Search results for "Biosynthesi"
showing 10 items of 526 documents
Efficacy and safety of cyclic pyranopterin monophosphate substitution in severe molybdenum cofactor deficiency type A: a prospective cohort study.
2015
Summary Background Molybdenum cofactor deficiency (MoCD) is characterised by early, rapidly progressive postnatal encephalopathy and intractable seizures, leading to severe disability and early death. Previous treatment attempts have been unsuccessful. After a pioneering single treatment we now report the outcome of the complete first cohort of patients receiving substitution treatment with cyclic pyranopterin monophosphate (cPMP), a biosynthetic precursor of the cofactor. Methods In this observational prospective cohort study, newborn babies with clinical and biochemical evidence of MoCD were admitted to a compassionate-use programme at the request of their treating physicians. Intravenous…
Designer membraneless organelles enable codon reassignment of selected mRNAs in eukaryotes.
2019
How to make an organelle in eukaryotes A key step in the evolution of complex organisms like eukaryotes was the organization of specific tasks into organelles. Reinkemeier et al. designed an artificial, membraneless organelle into mammalian cells to perform orthogonal translation. In response to a specific codon in a selected messenger RNA, ribosomes confined to this organelle were able to introduce chemical functionalities site-specifically, expanding the canonical set of amino acids. This approach opens possibilities in synthetic cell engineering and biomedical research. Science , this issue p. eaaw2644
Application of Cell Culture for the Production of Bioactive Compounds from Sponges: Synthesis of Avarol by Primmorphs from Dysidea avara
2000
Among all metazoan phyla, sponges are known to produce the largest number of bioactive compounds. However, until now, only one compound, arabinofuranosyladenine, has been approved for application in humans. One major obstacle is the limited availability of larger quantities of defined sponge starting material. Recently, we introduced the in vitro culture of primmorphs from Suberites domuncula, which contain proliferating cells. Now we have established the primmorph culture also from the marine sponge Dysidea avara and demonstrate that this special form of sponge cell aggregates produces avarol, a sesquiterpenoid hydroquinone, known to display strong cytostatic activity especially against ma…
Identification, sequence and mRNA expression pattern during metamorphosis of a cDNA encoding a glycine-rich cuticular protein in Tenebrio molitor
1995
The study of insect cuticular proteins and their sequences is of interest because they are involved in protein-protein and protein-chitin interactions which confer the mechanical properties and fine architecture of the cuticle. Moreover, in the coleopteran Tenebrio molitor there is a dramatic change in cuticular architecture between pre- and postecdysial secretion. We report the isolation, by differential screening, and the sequence characterization of a cDNA clone encoding a cuticular protein of T. molitor, ACP17. After insertion in the expression vector pEX1, the recognition of the fusion protein by an anti-cuticular monoclonal antibody confirmed the cuticular nature of ACP17. Northern hy…
Metabolic relation of cyanobacteria to aromatic compounds
2018
Cyanobacteria, also known as blue-green (micro)algae, are able to sustain many types of chemical stress because of metabolic adaptations that allow them to survive and successfully compete in a variety of ecosystems, including polluted ones. As photoautotrophic bacteria, these microorganisms synthesize aromatic amino acids, which are precursors for a large variety of substances that contain aromatic ring(s) and that are naturally formed in the cells of these organisms. Hence, the transformation of aromatic secondary metabolites by cyanobacteria is the result of the possession of a suitable “enzymatic apparatus” to carry out the biosynthesis of these compounds according to cellular requireme…
The Biosynthesis of Rare Homo-Amino Acid Containing Variants of Microcystin by a Benthic Cyanobacterium
2019
Microcystins are a family of chemically diverse hepatotoxins produced by distantly related cyanobacteria and are potent inhibitors of eukaryotic protein phosphatases 1 and 2A. Here we provide evidence for the biosynthesis of rare variants of microcystin that contain a selection of homo-amino acids by the benthic cyanobacterium Phormidium sp. LP904c. This strain produces at least 16 microcystin chemical variants many of which contain homophenylalanine or homotyrosine. We retrieved the complete 54.2 kb microcystin (mcy) gene cluster from a draft genome assembly. Analysis of the substrate specificity of McyB1 and McyC adenylation domain binding pockets revealed divergent substrate specificity …
Biosynthesis and maintenance of GSH in primary astrocyte cultures: role of L-cystine and ascorbate.
1995
Abstract We have studied the optimal conditions to maintain the astrocyte GSH levels under normal and oxidative stress conditions. The rate of GSH synthesis from l -methionine was statistically lower than from l -cystine or N -acetyl-cysteine in astrocytes treated with diethyl-maleate, which is substrate of GSH S-transferases. This is in accordance with the fact that cystathionase activity was not detectable. The transport of l -cystine mediated by the Na + -independent system Xc − is the limiting step in GSH synthesis in astrocytes. Incubation with tert-butyl hydroperoxide (t-booH) reduced GSH concentration in astrocytes. This reduction was ameliorated in part by the addition of ascorbate …
Subcellular localization of pentachlorophenol 4-monooxygenase in Sphingobium chlorophenolicum ATCC 39723.
2002
Abstract We have studied the subcellular localization of pentachlorophenol 4-monooxygenase (PCP4MO) in Sphingobium chlorophenolicum ATCC 39723 during induction by pentachlorophenol (PCP). Using a monoclonal antibody CL6 specific to the native and recombinant PCP4MO, the enzyme was primarily found soluble as determined by immunoblot and ELISA analyses of cellular fractions. However, the enzyme was observed both in the soluble and membrane-bound forms during induction for 2–4 h, suggesting its translocation out from the cytoplasm. Electron microscopy confirmed that PCP4MO was predominantly present in the cytoplasm at 1 h, whereas at 4 h significant amount was detected also in the membrane and…
Deciliation: A stressful event for Paracentrotus lividus embryos.
1998
In this report, by using mono- and two-dimensional electrophoretic analysis, we demonstrate that deciliation on sea urchin embryos induces a stress response. Deciliation indeed causes not only the activation of ciliary subroutine, but also a transient decrease of bulk protein synthesis. This decrease is in agreement with our previous results on heat shock response in sea urchin, although deciliation does not induce the expression of the same main hsp set. We were able to characterize one main deciliation-stress protein of 40 kDa whose expression is transiently induced by deciliation and whose localisation is likely to be nuclear.
ENO1 gene product binds to the c-myc promoter and acts as a transcriptional repressor: relationship with Myc promoter-binding protein 1 (MBP-1).
2000
The Myc promoter-binding protein-1 (MBP-1) is a 37-38 kDa protein that binds to the c-myc P2 promoter and negatively regulates transcription of the protooncogene. MBP-1 cDNA shares 97% similarity with the cDNA encoding the glycolytic enzyme alpha-enolase and both genes have been mapped to the same region of human chromosome 1, suggesting the hypothesis that the two proteins might be encoded by the same gene. We show here data indicating that a 37 kDa protein is alternatively translated from the full-length alpha-enolase mRNA. This shorter form of alpha-enolase is able to bind the MBP-1 consensus sequence and to downregulate expression of a luciferase reporter gene under the control of the c…