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1.
Adam P. Sharples Nasser Al‐Shanti Claire E. Stewart 《Journal of cellular physiology》2010,225(1):240-250
Reduced muscle mass and increased susceptibility to TNF‐induced degradation accompany inflamed ageing and chronic diseases. Furthermore, C2 myoblasts display diminished differentiation and increased susceptibility to TNF‐α‐induced cell death versus subcloned C2C12 cells, providing relevant models to assess: differentiation (creatine kinase), growth (protein), death (trypan‐blue) and anabolic/catabolic parameters (RT‐PCR) over 72 h ± TNF‐α (20 ng ml?1). At 48 and 72 h, respectively, larger myotubes and significantly higher CK activity (320.26 ± 6.82 vs. 30.71 ± 2.5, P < 0.05; 544.94 ± 27.7 vs. 39.4 ± 3.37 mU mg ml?1, P < 0.05), fold increases in myoD (21.45 ± 3.12 vs. 3.97 ± 1.76, P < 0.05; 31.07 ± 3.1 vs. 6.82 ± 1.93, P < 0.05) and myogenin mRNA (241.8 ± 40 vs. 36.80 ± 19.3, P < 0.05; 440 ± 100.5 vs. 201.1 ± 86, P < 0.05) were detected in C2C12 versus C2. C2C12 showed significant increases in IGF‐I mRNA (243.05 ± 3.87 vs. 105.75 ± 21.95, P < 0.05), reduced proliferation and significantly lower protein expression (1.21 ± 0.28 vs. 1.79 ± 0.29 mg ml?1, P < 0.05) at 72 h versus C2 cells. Significant temporal reductions in C2C12 IGFBP2 mRNA (28.02 ± 15.44, 13.82 ± 8.07, 6.92 ± 4.37, P < 0.05) contrasted increases in C2s (4.31 ± 3.31, 13.02 ± 9.92, 82.9 ± 58.9, P < 0.05) at 0, 48 and 72 h, respectively. TNF‐α increased cell death in C2s (2.67 ± 1.54%, 34.42 ± 5.39%, 29.71 ± 5.79% (0, 48, 72 h), P < 0.05), yet was without effect in C2C12s at 48 h but caused a small significant increase at 72 h (9.88 ± 4.02% (TNF‐α) vs. 6.17 ± 0.749% (DM), 72 h). TNF‐α and TNFRI mRNA were unchanged; however, larger reductions in IGF‐I (8.2‐ and 7.5‐fold vs. 4.5‐ and 4.1‐fold (48, 72 h)), IGF‐IR (2‐fold vs. no‐significant reduction (72 h)) and IGFBP5 (3.24 vs. 1.38 (48 h) and 2.21 vs. 1.71 (72 h), P < 0.05) mRNA were observed in C2 versus C2C12 with TNF‐α. This investigation provides insight into regulators of altered basal hypertrophy and TNF‐induced atrophy, providing a model for future investigation into therapeutic initiatives for ageing/wasting disorders. J. Cell. Physiol. 225: 240–250, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
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Summary Sperm whale apomyoglobin was expressed to high levels on minimal media and isotopically labeled with 13C and 15N nuclei. The isotopically labeled apoprotein was purified to homogeneity in a single step by reversed-phase chromatography and reconstituted with hemin and carbon monoxide gas for NMR analysis. Sequence-specific backbone 1HN, 15N and 13C as well as side-chain 13C resonance assignments have been made for over 90% of the amino acids in the carbon monoxide complex of the protein. Resonance assignments were made by analysis of a series of 3D triple resonance spectra measured on the uniformly labeled sample. These assignments will provide the basis for analyzing the effects of point site mutations on the structure, stability and dynamics of the protein in solution. 相似文献
4.
Summary The occurrence of the dominant ‘whey’ protein in samples of milk from 1180 sows is examined. It exhibits genetic polymorphism
with some unusual features. Although immunologically different from bovine β-lactoglobulin, it is shown by chemical studies
of the isolated protein to be a β-lactoglobulin. Two homozygous genetic variants, designated porcine β-lactoglobulin A and
C, are isolated and their amino acid compositions and peptide maps compared. It is shown that the C variant has +1 His, −1
Gln, and +1 Asp, −1 Glu, with respect to the A variant. These variants, containingca. 162 residues per molecule, are considered in relationship to porcine β-lactoglobulins isolated by other workers. The sequence
of the first 50 residues is determined and compared with sequence of the bovine protein. The sequences ofca. 70% of the remaining residues is proposed on the basis of the composition of tryptic peptides and assumed homology. 相似文献
5.
Helena Korpelainen Viivi Virtanen Kirsi Kostamo Henry Väre 《Plant Systematics and Evolution》2010,284(3-4):141-151
The diversification and distribution of Abies species throughout the Mediterranean region has led to a complex of species which are difficult to classify. An open question is whether these mainly allopatric taxa have exchanged genetic information via secondary contact. We studied the variation and geographic distribution of paternally inherited chloroplast DNA markers in nine Mediterranean Abies taxa. Markers with high and low mutation rates were applied in order to differentiate among a scenario of secondary genetic contact and a scenario of complete isolation after speciation. The observed molecular variation was analysed using statistical parsimony, geostatistics, and measures of population genetic differentiation. Ancient paternal lineages, represented by markers with low mutation rates, were shared among species. The central and widespread A. alba retained all ancient lineages whereas other species exhibited fewer, down to a single lineage. In contrast, modern lineages, depicted by markers with high mutation rates, were largely separated among species. The western Mediterranean A. pinsapo and A. numidica were clearly separated from each other and from the remaining Abies species. This indicates the absence of secondary contact. The same scenario applies to the eastern Mediterranean Abies species. An exception is the parapatric complex of A. alba, A. cephalonica, and their supposed hybrid A. borisii regis, which exhibited evidence of secondary contact. 相似文献
6.
Protein kinase Cζ (PKCζ) is a member of the PKC family, serving downstream of insulin receptor and phosphatidylinositol (PI)
3-kinase. Many evidences suggest that PKCζ plays a very important role in activating glucose transport response. Not only
insulin but also glucose and exercise can activate PKCζ through diverse pathways. PKCζ activation and activity are impaired
with insulin resistance in muscle and adipose tissues of type II diabetes individuals, but heightened in liver tissue, wherein
it also increases lipid synthesis mediated by SREBP-1c (sterol-regulatory element-binding protein). Many studies have focused
on linkage between PKCζ and GLUT4 translocation and activation. Exploring the molecular mechanisms and pathways by which PKCζ
mediates glucose transport will highlight the insulin-signaling pathway.
Published in Russian in Biokhimiya, 2006, Vol. 71, No. 7, pp. 869–875.
Co-first authors. 相似文献
7.
The in-situ inter- and intracellular localization patterns of phosphoenolpyruvate (PEP) and ribulose 1,5-bisphosphate (RuBP) carboxylases in green leaves of severalPanicum species were investigated using an indirect immunofluorescence technique. Four species were examined and compared:P. miliaceum (C4),P. bisulcatum (C3), andP. decipiens andP. milioides (C3–C4 intermediates which have Kranz-like leaf anatomy and reduced photorespiration). In the C4
Panicum, PEP carboxylase was located in the cytosol of the mesophyll cells and RuBP carboxylase was restricted to the bundle-sheath chloroplasts. In contrast, in the C3
Panicum species, PEP carboxylase was found throughout the leaf chlorenchyma, in both the cytosol and chloroplasts, and RuBP carboxylase was located in the chloroplasts. For the C3–C4 intermediate plants, the patterns depended on the species examined. ForP. decipiens, the in-situ localization of both carboxylases was similar to that described forP. bisulcatum and other C3 plants. However, inP. milioides, PEP carboxylase was found exclusively in the cytosol of the mesophyll cells, as inP. miliaceum and other C4 species, whereas RuBP carboxylase was distributed in both the mesophyll and bundle-sheath chloroplasts.Abbreviations PEP
phosphoenolpyruvate
- RuBP
ribulose 1,5-bisphosphate 相似文献
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Summary
Bacillus stearothermophilus was adapted to grow at 55°C and 37°C in a complex medium with almost equivalent yields in cell mass. In both temperature
ranges the maximum specific growth rates (μmax) were identical.
Cellular extracts of this bacterium showed remarkable differences in the activity levels of several enzymes, depending on
the respective growth temperature.
High activities of glyceraldehyde-3-phosphate dehydrogenase and alcohol dehydrogenase were observed in bacteria from thermophilic
cultures (55°C) and the respiratory quotient exceeded 1.0. Under anaerobic conditions at 55°C μmax was the same as in aerobic cultures.
No alcohol dehydrogenase was detected in cells from mesophilic cultures (37°C), however, and the level of glyceraldehyde-3-phosphate
dehydrogenase was also extremely low under mesophilic conditions. Succinate dehydrogenase and isocitrate dehydrogenase activity
appeared to be higher in bacteria grown at 37°C; the resspiratory quotient was always lower than 1.0.
At 37°C, acetoin formation was observed regularly, a fermentation product which was never detected in 55°C-cultures. Under
anaerobic conditions at 37°C a very low growth rate was found. When adapted to grow at 37°C or 55°C,B. stearothermophilus is apparently able to use different catabolic systems. 相似文献
11.
The aim of this investigation was to elucidate the reductions in muscle, skin and core temperature following exposure to −110°C whole body cryotherapy (WBC), and compare these to 8°C cold water immersion (CWI). Twenty active male subjects were randomly assigned to a 4-min exposure of WBC or CWI. A minimum of 7 days later subjects were exposed to the other treatment. Muscle temperature in the right vastus lateralis (n = 10); thigh skin (average, maximum and minimum) and rectal temperature (n = 10) were recorded before and 60 min after treatment. The greatest reduction (P<0.05) in muscle (mean ± SD; 1 cm: WBC, 1.6±1.2°C; CWI, 2.0±1.0°C; 2 cm: WBC, 1.2±0.7°C; CWI, 1.7±0.9°C; 3 cm: WBC, 1.6±0.6°C; CWI, 1.7±0.5°C) and rectal temperature (WBC, 0.3±0.2°C; CWI, 0.4±0.2°C) were observed 60 min after treatment. The largest reductions in average (WBC, 12.1±1.0°C; CWI, 8.4±0.7°C), minimum (WBC, 13.2±1.4°C; CWI, 8.7±0.7°C) and maximum (WBC, 8.8±2.0°C; CWI, 7.2±1.9°C) skin temperature occurred immediately after both CWI and WBC (P<0.05). Skin temperature was significantly lower (P<0.05) immediately after WBC compared to CWI. The present study demonstrates that a single WBC exposure decreases muscle and core temperature to a similar level of those experienced after CWI. Although both treatments significantly reduced skin temperature, WBC elicited a greater decrease compared to CWI. These data may provide information to clinicians and researchers attempting to optimise WBC and CWI protocols in a clinical or sporting setting. 相似文献
12.
In development, T cells first express their antigen receptors in the thymus, where they may undergo selection processes leading to major histocompatibility complex (MHC) restriction and tolerance. A high proportion of thymocytes are thought to fail this selection in some way and to be destined for intrathymic death. These cells are categorized as the cortical type since they constitute most of the cortical cells; they express both CD4 and CD8 antigens but only very low levels of MHC class I antigens. One suggested cause of thymocyte death is a failure to produce a functional T cell receptor (Tcr) due to errors in the rearrangements of germline DNA, resulting in V regions being absent or incorrectly spliced to the other segments of the transcribed gene. We have sequenced from the C region through to the V region of 14 rat Tcr chain clones isolated from thymocyte cDNA libraries. Of the 14, 13 have complete and correct rearrangements, whereas one was expressed from an unrearranged gene. Most of these clones are likely to be derived from the cortical population, for Northern blot analysis showed that these cells and total thymocytes expressed similar amounts of chain mRNA.Furthermore, the RNA from cortical-type cells contained a very similar ratio of full-length to truncated chain mRNA as did activated thymocytes and mature T lymphocytes. The data imply that defective chain gene rearrangement is not a major cause of failure in the selection of thymocytes. The sequences of the rat Tcr and chain constant regions are also reported. 相似文献
13.
Phosphoenolpyruvate carboxylase (PEPCase; EC 4.1.1.31) from Flaveria trinervia Mohr (C4), F. floridana Johnston (C3–C4), and F. cronquistii Powell (C3) leaves were compared by electrotransfer blotting/enzyme-linked immunoassay (Western-blot analysis), mobility of the native enzyme in polyacrylamide gels and in isoelectric focusing (IEF) gels, peptide mapping, and in-vitro translation of RNA isolated from each plant. The PEPCases from the C3 and C3–C4 plants were very similar to each other in terms of electrophoretic mobilities on gels and isoenzyme patterns on IEF gels, and identical in peptide mapping. Quantitative differences were noted, however, in that the C3–C4 intermediate plant contained more PEPCase overall and that the relative activity of individual isoenzymes shifted between the C3 and C3–C4 intermediate PEPCases. The PEPCase from the C4 plant had a different isoenzyme pattern, a different peptide map, and was far more abundant than the other two enzymes. Western blot analysis demonstrated the cross-reactivity of PEPCases from all three Flaveria species with antibody raised against maize PEPCase. The results provide evidence, at the molecular level, that supports the view of C3–C4 intermediate species as C3-like plants with some C4-like photosynthetic characteristics, but there are differences from the C3 plant in the quantity and properties of the PEPCase from the C3–C4 intermediate plant.Abbreviations IEF
isoelectric focusing
- kDa
kilodalton
- PEPCase
phosphoenolpyruvate carboxylase
- Rubisco
Ribulose-1,5-bisphosphate carboxylase/oxygenase 相似文献
14.
The concentrations of 17 nucleotides and three nucleosides have been determined in a batch suspension culture of Datura innoxia using a new procedure for extraction, purification and high-performance liquid chromatography separation of these compounds. The nucleotide pools change appreciably in the different phases of growth. These changes indicate the preparation for and initiation of cell proliferation, and reflect metabolic events during cell division, cell elongation and starvation. The main components of the nucleotide pool are uracil nucleotides, with uridine 5-diphosphate sugars as the predominant fraction, and the adenine nucleotides. Although their concentrations vary by a factor of more than 6 the ratio of the uracil to adenine nucleotides is kept fairly constant during growth. The energy charge is maintained at a rather high value. The correlation of these events with nutrient uptake and macromolecular synthesis by the batch culture is presented in the following paper.Abbreviations Glc
glucose
- GlcNAc
2-acetamido-2-deoxy-d-glucose
- HPLC
high performance liquid chromatography
- UDP
uridine 5-diphosphate 相似文献
15.
Nada Horvatin?i? Ines Krajcar Broni?Bogomil Obeli? 《Palaeogeography, Palaeoclimatology, Palaeoecology》2003,193(1):139-157
We studied Holocene speleothems and tufa samples collected in numerous caves and rivers in the Dinaric Karst of Croatia, Slovenia, Bosnia and Herzegovina, as well as Serbia and Montenegro. Differences in the formation process of tufa and speleothems are discussed in the context of their isotopic composition (14C, 13C and 18O), as well as the chemistry of surface water (rivers, lakes) and drip water (in caves). The physical and chemical parameters monitored in the surface water (tufa precipitation) and drip water (speleothem precipitation) show that more stable conditions accompany speleothem rather than tufa formation. This is particularly obvious in the water temperature variations (2-22°C in surface water and 7-12°C in drip water) and in saturation index variation (3-11 in surface water and 1-6 in drip water). The range of 14C ages recorded by Holocene speleothems (∼12?000 yr) is wider by several thousands years than that of Holocene tufa samples (∼6000 yr). δ13C values for tufa samples range from −12‰ to −6‰ and for speleothem samples from −12‰ to +3‰ reflecting higher soil carbon and/or vegetation impact on the process of tufa than on speleothem formation. The differences in δ18O values of tufa and speleothem samples from different areas reflect different temperature conditions and differing isotopic composition in the water. The study shows that speleothems from the Dinaric Karst can be used as global palaeoclimatic records, whereas tufa records changes in the local palaeoenvironment. 相似文献
16.
Divya Sriram Kunal Dayma Ambure Sharada Devi Akhouri Kishore Raghawan Shivali Rawat Vegesna Radha 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2021,1868(5):118964
GSK3β, a ubiquitously expressed Ser/Thr kinase, regulates cell metabolism, proliferation and differentiation. Its activity is spatially and temporally regulated dependent on external stimuli and interacting partners, and its deregulation is associated with various human disorders. In this study, we identify C3G (RapGEF1), a protein essential for mammalian embryonic development as an interacting partner and substrate of GSK3β. In vivo and in vitro interaction assays demonstrated that GSK3β and Akt are present in complex with C3G. Molecular modelling and mutational analysis identified a domain in C3G that aids interaction with GSK3β, and overlaps with its nuclear export sequence. GSK3β phosphorylates C3G on primed as well as unprimed sites, and regulates its subcellular localization. Over-expression of C3G resulted in activation of Akt and inactivation of GSK3β. Huntingtin aggregate formation, dependent on GSK3β inhibition, was enhanced upon C3G overexpression. Stable clones of C2C12 cells generated by CRISPR/Cas9 mediated knockdown of C3G, that cannot differentiate, show reduced Akt activity and S9-GSK3β phosphorylation compared to wild type cells. Co-expression of catalytically active GSK3β inhibited C3G induced myocyte differentiation. C3G mutant defective for GSK3β phosphorylation, does not alter S9-GSK3β phosphorylation and, is compromised for inducing myocyte differentiation. Our results show complex formation and reciprocal regulation between GSK3β and C3G. We have identified a novel function of C3G as a negative regulator of GSK3β, a property important for its ability to induce myogenic differentiation. 相似文献
17.
Four populations of Mollugo verticillata L. were compared on the basis of their photosynthetic products, photosynthetic rates, enhancement under low oxygen concentration, and CO2 compensation points. In addition, pulse-chase labeling experiments were conducted using one of the four populations. Depending on the plant population, C4 acids ranged from 40% to 11% of the primary products under short-term exposure to 14CO2. These compounds were also metabolized during pulse-chase experiments. All four populations had significantly different photosynthetic rates and those rates were correlated with the amounts of labelled C4 acids produced and C4-acid turnover. Three populations of M. verticillata had similar compensation points (40 l/l) and degrees of photosynthetic enhancement under low [O2] (20%), the fourth population was much lower in both characteristics (CO2 compensation, 25 l/l; low-O2 enhancement, 12%). The results verify the intermediate nature of photosynthesis in this species, and illustrate populational differences in its photosynthetic and photorespiratory carbon metabolism.Abbreviations PGA
3-phosphoglyceric acid
- Kan
Kansas
- Mass
Massachusetts
- Mex
Mexico 相似文献
18.
Hidetaka Torigoe Itaru Okamoto Takenori Dairaku Yoshiyuki Tanaka Akira Ono Tetsuo Kozasa 《Biochimie》2012
Metal ion-nucleic acid interactions have attracted considerable interest for their involvement in structure formation and catalytic activity of nucleic acids. Although interactions between metal ion and mismatched base pair duplex are important to understand mechanism of gene mutations related to heavy metal ions, they have not been well-characterized. We recently found that the Ag+ ion stabilized a C:C mismatched base pair duplex DNA. A C–Ag–C metal-mediated base pair was supposed to be formed by the binding between the Ag+ ion and the C:C mismatched base pair to stabilize the duplex. Here, we examined specificity, thermodynamics and structure of possible C–Ag–C metal-mediated base pair. UV melting indicated that only the duplex with the C:C mismatched base pair, and not of the duplexes with the perfectly matched and other mismatched base pairs, was specifically stabilized on adding the Ag+ ion. Isothermal titration calorimetry demonstrated that the Ag+ ion specifically bound with the C:C base pair at 1:1 molar ratio with a binding constant of 106 M−1, which was significantly larger than those for nonspecific metal ion-DNA interactions. Electrospray ionization mass spectrometry also supported the specific 1:1 binding between the Ag+ ion and the C:C base pair. Circular dichroism spectroscopy and NMR revealed that the Ag+ ion may bind with the N3 positions of the C:C base pair without distorting the higher-order structure of the duplex. We conclude that the specific formation of C–Ag–C base pair with large binding affinity would provide a binding mode of metal ion-DNA interactions, similar to that of the previously reported T-Hg-T base pair. The C–Ag–C base pair may be useful not only for understanding of molecular mechanism of gene mutations related to heavy metal ions but also for wide variety of potential applications of metal-mediated base pairs in various fields, such as material, life and environmental sciences. 相似文献
19.
Aldolases are a specific group of lyases that catalyze the reversible stereoselective addition of a donor compound (nucleophile) onto an acceptor compound (electrophile). Whereas most aldolases are specific for their donor compound in the aldolization reaction, they often tolerate a wide range of aldehydes as acceptor compounds. C–C bonding by aldolases creates stereocenters in the resulting aldol products. This makes aldolases interesting tools for asymmetric syntheses of rare sugars or sugar-derived compounds as iminocyclitols, statins, epothilones, and sialic acids. Besides the well-known fructose 1,6-bisphosphate aldolase, other aldolases of microbial origin have attracted the interest of synthetic bio-organic chemists in recent years. These are either other dihydroxyacetone phosphate aldolases or aldolases depending on pyruvate/phosphoenolpyruvate, glycine, or acetaldehyde as donor substrate. Recently, an aldolase that accepts dihydroxyacetone or hydroxyacetone as a donor was described. A further enlargement of the arsenal of available chemoenzymatic tools can be achieved through screening for novel aldolase activities and directed evolution of existing aldolases to alter their substrate- or stereospecifities. We give an update of work on aldolases, with an emphasis on microbial aldolases. 相似文献
20.
Bernhard Pfeiffer Kurt Hauenstein Philipp Merz Jürg Gertsch Karl-Heinz Altmann 《Bioorganic & medicinal chemistry letters》2009,19(14):3760-3763
The SAR of a series of new epothilone A derivatives with a 2-substituted-1,3-oxazoline moiety trans-fused to the C12–C13 bond of the deoxy macrocycle have been investigated with regard to tubulin polymerization induction and cancer cell growth inhibition. Significant differences in antiproliferative activity were observed between different analogs, depending on the nature of the substituent at the 2-position of the oxazoline ring. The most potent compounds showed comparable activity with the natural product epothilone A. Modeling studies provide a preliminary rationale for the observed SAR. 相似文献