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Ivan Lule Pieter-Jan D’Huys Lieve Van Mellaert Jozef Anné Kristel Bernaerts Jan Van Impe 《Mathematical biosciences》2013
The metabolic impact exerted on a microorganism due to heterologous protein production is still poorly understood in Streptomyces lividans. In this present paper, based on exometabolomic data, a proposed genome-scale metabolic network model is used to assess this metabolic impact in S. lividans. Constraint-based modeling results obtained in this work revealed that the metabolic impact due to heterologous protein production is widely distributed in the genome of S. lividans, causing both slow substrate assimilation and a shift in active pathways. Exchange fluxes that are critical for model performance have been identified for metabolites of mouse tumor necrosis factor, histidine, valine and lysine, as well as biomass. Our results unravel the interaction of heterologous protein production with intracellular metabolism of S. lividans, thus, a possible basis for further studies in relieving the metabolic burden via metabolic or bioprocess engineering. 相似文献
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Juan Du Yan Cao Qian Wang Nana Zhang Xiaoyu Liu Dandan Chen Xiaoyun Liu Qunyuan Xu Wei Ma 《Cell cycle (Georgetown, Tex.)》2015,14(22):3566-3579
Polo-like kinase 1 (Plk1) is pivotal for proper mitotic progression, its targeting activity is regulated by precise subcellular positioning and phosphorylation. Here we assessed the protein expression, subcellular localization and possible functions of phosphorylated Plk1 (pPlk1Ser137 and pPlk1Thr210) in mouse oocytes during meiotic division. Western blot analysis revealed a peptide of pPlk1Ser137 with high and stable expression from germinal vesicle (GV) until metaphase II (MII), while pPlk1Thr210 was detected as one large single band at GV stage and 2 small bands after germinal vesicle breakdown (GVBD), which maintained stable up to MII. Immunofluorescence analysis showed pPlk1Ser137 was colocalized with microtubule organizing center (MTOC) proteins, γ-tubulin and pericentrin, on spindle poles, concomitantly with persistent concentration at centromeres and dynamic aggregation between chromosome arms. Differently, pPlk1Thr210 was persistently distributed across the whole body of chromosomes after meiotic resumption. The specific Plk1 inhibitor, BI2536, repressed pPlk1Ser137 accumulation at MTOCs and between chromosome arms, consequently disturbed γ-tubulin and pericentrin recruiting to MTOCs, destroyed meiotic spindle formation, and delayed REC8 cleavage, therefore arresting oocytes at metaphase I (MI) with chromosome misalignment. BI2536 completely reversed the premature degradation of REC8 and precocious segregation of chromosomes induced with okadaic acid (OA), an inhibitor to protein phosphatase 2A. Additionally, the protein levels of pPlk1Ser137 and pPlk1Thr210, as well as the subcellular distribution of pPlk1Thr210, were not affected by BI2536. Taken together, our results demonstrate that Plk1 activity is required for meiotic spindle assembly and REC8 cleavage, with pPlk1Ser137 is the action executor, in mouse oocytes during meiotic division. 相似文献
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Gregório Miguel Ferreira de Camargo Raphael Bermal Costa Lucia Galvão de Albuquerque Luciana Correia de Almeida Regitano Fernando Baldi Humberto Tonhati 《Gene》2014
Reproductive traits have a high economic value and it is interesting to include them in the selection objectives of an animal breeding program. These traits generally show low heritability and molecular markers may therefore be used in genetic evaluations to improve the accuracy of predictions. The JY-1 gene is expressed in the oocyte and it is associated with folliculogenesis and early embryo development. It has been suggested to affect reproductive traits. In this study, exons 1 and 2 of the JY-1 gene were studied in 385 Nellore females by PCR-sequencing. Seventeen polymorphisms were identified. After analysis of linkage disequilibrium, association tests were performed between eight SNPs and the occurrence of early pregnancy, age at first calving, days to calving, and reconception of primiparous heifers. Seven SNPs were significant for three traits. The most significant was chr29:12,999 T/A (p = 0.003) which was associated with the occurrence of early pregnancy. This SNP might be involved in protein translation inhibition since it affects the initial methionine codon. The JY-1, an oocyte specific gene, influences reproductive traits; further studies investigating other regions of the gene or other genes expressed in tissues of the female reproductive system would be interesting to be performed. 相似文献
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Nabanita De 《Journal of molecular biology》2009,393(3):619-363
The bacterial second messenger bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) controls secretion, cell adhesion, and motility, leading to biofilm formation and increased cytotoxicity. Diguanylate cyclases containing GGDEF and phosphodiesterases containing EAL or HD-GYP domains have been identified as the enzymes controlling cellular c-di-GMP levels, yet less is known regarding the molecular mechanisms governing regulation and signaling specificity. We recently determined a product-inhibition pathway for the diguanylate cyclase response regulator WspR from Pseudomonas, a potent molecular switch that controls biofilm formation. In WspR, catalytic activity is modulated by a helical stalk motif that connects its phospho-receiver and GGDEF domains. The stalks facilitate the formation of distinct oligomeric states that contribute to both activation and autoinhibition. Here, we provide novel insights into the regulation of diguanylate cyclase activity in WspR based on the crystal structures of full-length WspR, the isolated GGDEF domain, and an artificially dimerized catalytic domain. The structures highlight that inhibition is achieved by restricting the mobility of rigid GGDEF domains, mediated by c-di-GMP binding to an inhibitory site at the GGDEF domain. Kinetic measurements and biochemical characterization corroborate a model in which the activation of WspR requires the formation of a tetrameric species. Tetramerization occurs spontaneously at high protein concentration or upon addition of the phosphomimetic compound beryllium fluoride. Our analyses elucidate common and WspR-specific mechanisms for the fine-tuning of diguanylate cyclase activity. 相似文献
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Ersilia De Lorenzi Anthony F. Fell Alan L. Holmes Gabriele Caccialanza Gabriella Massolini Carlo Gandini Mikes Kitsos Carolina Ponci 《Chirality》1993,5(8):622-626
Three chiral calcium antagonist drugs, bepridil and two dihydropyridine derivatives (nicardipine and REC 15/2375), have been successfully separated within short retention times using either the α1-acid glycoprotein chiral stationary phase (Chiral AGP) or the ovomucoid column (Ultron ES-OVM). Aqueous buffer at defined pH is modified by the addition of an organic component (propan-2-ol, acetonitrile, ethanol) in order to modulate the retention properties of each system. The influence of pH and percentage of organic modifier on retention, selectivity, resolution, and column performance are discussed for bepridil analyzed on Chiral AGP and for the two dihydropyridines (nicardipine and REC 15/2375) analyzed on Ultron ES-OVM stationary phases. © 1993 Wiley-Liss, Inc. 相似文献
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A unit Rad-Equivalent Chemical (REC) has been suggested for purposes of quantitating the mutagenic hazards of chemicals. The usefulness of this approach is demonstrated by the establishment of a constant relationship between the forward mutation frequency and haploid genome size in various organisms for both radiation and chemical EMS. However, it is necessary to determine the radiation equivalence of chemicals in as many organisms and for as many end-points as possible. For end-points we are limited to forward mutations. Another relevant genetic end-point of interest in this regard is gene conversion which can also monitor any kind of DNA damage in a suitable diploid system. Hence, we have determined the REC value for EMS in diploid yeast with gene conversion as the end-point. This agrees well with the REC values estimated in a number of organisms with forward mutation as the end-point. This finding further underlines the generality of the REC concept. 相似文献
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