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Living cells are able to respond to the surrounding environment. As a first step in this process, membrane receptors react with an extracellular ligand. There are three main families of cell-surface receptors: (1) Ion-channel-linked receptors, (2) G-protein-linked receptors, and (3) Enzyme-linked receptors that either act directly as enzymes or are associated with enzymes. These enzymes are oftenprotein kinasesthat phosphorylate specific proteins in the target cell. Through cascades of phosphorylations elaborate sets of proteins relay signals from the receptor to the nucleus regulating gene expression. There are two groups of protein kinases: tyrosine- and serine-threonine-specific protein kinases and there areprotein phosphataseswith specificity for the appropriate side chain to match each type of kinase. They can terminate an activation event reversing the phosphorylation caused by a protein kinase.

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Glutathione (g-L-glutamyl-L-cysteinyl-glycine; GSH) shares structural similarities with the b-lactam biosynthetic intermediate ACV-tripeptide {d-(L-a-aminoadipyl)-L-cysteinyl-D-valine}. Not surprisingly, GSH has been reported to inhibit the b-lactam biosynthetic machinery quite effectively and, hence, strategies to decrease the intracellular GSH concentrations without influencing negatively the physiological status of idiophasic mycelia would attract industrial interests. Here we present a detailed map of the GSH metabolic network of P. chrysogenum and show a promising way to keep the GSH pool selectively down under penicillin producing conditions. This procedure includes a well-controlled and transient lowering of pH at the beginning of the production phase, and it relies on the GSH-dependent detoxification of the protonophore penicillin side-chain precursors phenoxyacetic acid (POA) and phenylacetic acid (PA). Encouraging preliminary fed-batch fermentation experiments have been performed to test this technological proposal. Interestingly, the mechanism of the activation of POA and PA to the appropriate CoA derivatives has remained yet to be answered but the involvement of GSH seems to be rather unlikely in this case. Our data also challenge the hypothesis that the formation of different kinds of penicillins would be an alternative to GSH-dependent detoxification processes in P. chrysogenum.

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Changes in both the morphology and the steroidogenic activity of porcine ovaries denervated surgically on day 12 of the oestrous cycle were studied. Neurectomy of the plexus and the superior ovarian nerves caused a dramatic reduction in the number (or even a disappearance) of dopamine-β-hydroxylase- and/or neuropeptide tyrosine-immunoreactive nerve terminals. On day 20 of the subsequent oestrous cycle, the number of small follicles increased (P < 0.01) and that of large follicles decreased (P < 0.05) in the denervated ovaries, as compared to the controls. Neurectomy led to a decrease in the level of progesterone (P 4 ; P < 0.001) and androstenedione (A 4 ; P < 0.01) in the fluid from small follicles, A 4 (P < 0.001) and testosterone (T; P < 0.05) in the fluid from medium-sized follicles, as well as in the content of all these steroids in the fluid from large-sized follicles (P < 0.001 for P 4 and P < 0.05 for A 4 and T). Denervation also caused a decrease in the content of A 4 (P < 0.01) and T (P < 0.001) in the wall of follicles. Neurectomy resulted in a significant increase in the immunoexpression of cholesterol side-chain cleavage cytochrome P450 in the follicles and a decrease of 3β-hydroxysteroid dehydrogenase. After denervation, plasma levels of LH, P 4 , A 4 , T, oestrone and oestradiol-17β were lower (P < 0.05–0.001) on the particular days of the study than in the control group. Our data revealed that the denervation of ovaries during the middle luteal phase of the oestrous cycle in gilts caused distinct changes in both the morphology and the steroidogenic activity of the organ, confirming an important role of the peripheral nervous system in the control of the gonad in this species.

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hydrophobic side chain; 20-YEML-23 is found in the NTD, and this signal motif in the late endosome contributes to the correct localisation of the IFITM3 protein, which protects from viral hemifusion to the host ( Jia et al., 2014 ). Furthermore, 75-F and 78-F

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Rice DA, Kirkman MS, Aitken LD, Mouw AR, Schimmer BP, Parker KL: Analysis of the promoter region of the gene encoding mouse cholesterol side-chain cleavage enzyme. J. Biol. Chem. 265(20), 11713–11720 (1990

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498 500 Kenne, L., Lindberg, B., Petersson, K., Katzenellenbogen, E., Romanowska, E.: Structural studies of the O-specific side-chains of the Shigella sonnei phase I

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Orvosi Hetilap
Authors: Krisztina Kőhalmy, Damjana Rozman, Jean-Marc Pascussi, Enikő Sárváry, and Katalin Monostory

Kandutsch, A. A., Chen, H. W.: Inhibition of sterol synthesis in cultured mouse cells by cholesterol derivatives oxygenated in the side chain. J. Biol. Chem., 1974, 249 , 6057–6061. Chen H. W

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Acta Physiologica Hungarica
Authors: Zorana Oreščanin-Dušić, Č. Miljević, M. Slavić, A. Nikolić-Kokić, D. Blagojević, D. Lečić-Toševski, and M. Spasić

, Letteron P, Pessayre D: Tianeptine, a new tricyclic antidepressant metabolized by beta-oxidation of its heptanoic side chain, inhibits the mitochondrial oxidation of medium and short chain fatty acids in mice. Biochem. Pharmacol. 38, 3743–3751 (1989

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Phe side chain arrangement of endomorphins using conformationally constrained analogues. J. Med. Chem. 47, 735–743 (2004) Toth G. Structure-activity study on the Phe side chain

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Acta Veterinaria Hungarica
Authors: Janusz Rząsa, Andrzej Sechman, Helena Paczoska-Eliasiewicz, and Anna Hrabia

Asem, E. K. and Hertelendy, F. (1986): Clomiphene and tamoxifen inhibit the cholesterol side-chain cleavage enzyme activity in hen granulosa cells. J. Reprod. Fertil. 77 , 153–158. Hertelendy F

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