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11.
Homocysteine thiolactone (HCTL) is a cyclic thioester of homocysteine, showing high reactivity toward lysine residues of proteins.
In the present study the structural properties and aggregation propensity of bovine pancreatic insulin were studied in the
presences of increasing concentration of HCTL (0–500 μM), using different spectroscopic techniques. As shown in this study,
HCTL induces gross structural alterations and subsequently aggregation of insulin in a dose dependent manner. Also induction
of insulin aggregation by HCTL occurs in a sequential process, where native protein with alpha-helical abundant structure
gradually transforms into partially folded conformations with the significant amount of beta-sheet. Since C-terminal B-chain
of insulin plays a critical role in stability of this protein, the structural alteration/aggregation induced by HCTL can be
consequence of homocysteinylation of the only Lysine residue (Lys29) on its B-chain. This study may have important implications
regarding the effect of HCTL on structure of insulin particularly in the pathological states linked to hyperhomocysteinemia. 相似文献
12.
Global patterns of leaf mechanical properties 总被引:1,自引:0,他引:1
Onoda Y Westoby M Adler PB Choong AM Clissold FJ Cornelissen JH Díaz S Dominy NJ Elgart A Enrico L Fine PV Howard JJ Jalili A Kitajima K Kurokawa H McArthur C Lucas PW Markesteijn L Pérez-Harguindeguy N Poorter L Richards L Santiago LS Sosinski EE Van Bael SA Warton DI Wright IJ Wright SJ Yamashita N 《Ecology letters》2011,14(3):301-312
Leaf mechanical properties strongly influence leaf lifespan, plant-herbivore interactions, litter decomposition and nutrient cycling, but global patterns in their interspecific variation and underlying mechanisms remain poorly understood. We synthesize data across the three major measurement methods, permitting the first global analyses of leaf mechanics and associated traits, for 2819 species from 90 sites worldwide. Key measures of leaf mechanical resistance varied c. 500-800-fold among species. Contrary to a long-standing hypothesis, tropical leaves were not mechanically more resistant than temperate leaves. Leaf mechanical resistance was modestly related to rainfall and local light environment. By partitioning leaf mechanical resistance into three different components we discovered that toughness per density contributed a surprisingly large fraction to variation in mechanical resistance, larger than the fractions contributed by lamina thickness and tissue density. Higher toughness per density was associated with long leaf lifespan especially in forest understory. Seldom appreciated in the past, toughness per density is a key factor in leaf mechanical resistance, which itself influences plant-animal interactions and ecosystem functions across the globe. 相似文献
13.
The AMPA receptor subunits GluR-A and GluR-B reciprocally modulate spinal synaptic plasticity and inflammatory pain 总被引:6,自引:0,他引:6
Hartmann B Ahmadi S Heppenstall PA Lewin GR Schott C Borchardt T Seeburg PH Zeilhofer HU Sprengel R Kuner R 《Neuron》2004,44(4):637-650
Ca(2+)-permeable AMPA receptors are densely expressed in the spinal dorsal horn, but their functional significance in pain processing is not understood. By disrupting the genes encoding GluR-A or GluR-B, we generated mice exhibiting increased or decreased numbers of Ca(2+)-permeable AMPA receptors, respectively. Here, we demonstrate that AMPA receptors are critical determinants of nociceptive plasticity and inflammatory pain. A reduction in the number of Ca(2+)-permeable AMPA receptors and density of AMPA channel currents in spinal neurons of GluR-A-deficient mice is accompanied by a loss of nociceptive plasticity in vitro and a reduction in acute inflammatory hyperalgesia in vivo. In contrast, an increase in spinal Ca(2+)-permeable AMPA receptors in GluR-B-deficient mice facilitated nociceptive plasticity and enhanced long-lasting inflammatory hyperalgesia. Thus, AMPA receptors are not mere determinants of fast synaptic transmission underlying basal pain sensitivity as previously thought, but are critically involved in activity-dependent changes in synaptic processing of nociceptive inputs. 相似文献
14.
Moosavi-Movahedi AA Gharanfoli M Jalili S Ahmad F Chamani J Hakimelahi GH Sadeghi M Amani M Saboury AA 《The protein journal》2006,25(2):117-125
The effect of stabilizing and destabilizing salts on the catalytic behavior of ribonuclease A (RNase A) was investigated at
pH 7.5 and 25°C, using spectrophotometric, viscometric and molecular dynamic methods. The changes in the distance between
Nε2 of His12 and Nδ1 of His119 at the catalytic center of RNase A upon the addition of sodium sulfate, sodium hydrogen sulfate and sodium thiocyanate were
evaluated by molecular dynamic methods. The compactness and expansion in terms of Stokes radius of RNase A upon the addition
of sulfate ions as kosmotropic salts, and thiocyanate ion as a chaotropic salt, were estimated by viscometric measurements.
Enzyme activity was measured using cytidine 2′, 3′-cyclic monophosphate as a substrate. The results from the measurements
of distances between Nε2 of His12 and Nδ1 of His119 and Stokes radius suggest (i) that the presence of sulfate ions decreases the distance between the catalytic His residues
and increases the globular compactness, and (ii) that there is an expansion of the enzyme surface as well as elongation of
the catalytic center in the presence of thiocyanate ion. These findings are in agreement with activity measurements. 相似文献
15.
Darya Habibi Reza B. Jalili Farshad Forouzandeh Christopher J. Ong Aziz Ghahary 《Journal of cellular physiology》2010,225(1):196-205
Indoleamine 2,3‐dioxygenase (IDO), a tryptophan degrading enzyme, is a potent immunomodulatory factor. IDO expression in fibroblasts selectively induces apoptosis in immune cells but not in primary skin cells. However, the mechanism(s) of this selective effect of IDO‐induced low tryptophan environment is not elucidated. The aim of present study was to investigate whether the activity of general control non‐derepressible‐2(GCN2) kinase stress‐responsive pathway and its known inhibitor, protein IMPACT homolog, in immune and skin cells are differentially regulated in response to IDO‐induced low tryptophan environment. IDO‐expressing human fibroblasts were co‐cultured with Jurkat cells, human T cells, fibroblasts, or keratinocytes. Activation of GCN2 pathway was significantly higher in immune cells exposed to IDO‐expressing environment relative to that of skin cells. In contrast, IMPACT was highly and constitutively expressed in skin cells while its expression was very low in stimulated T cells and undetectable in Jurkat cells. A significant IDO‐induced suppressive as well as apoptotic effect was demonstrated in IMPACT knocked down fibroblasts co‐cultured with IDO‐expressing fibroblasts. Proliferation of Jurkat cells, stably transduced with IMPACT‐expressing vector, was rescued significantly in tryptophan‐deficient but not IDO‐expressing environment. This may be due to the ability of IMPACT to recover the effects of IDO‐mediated tryptophan depletion (GCN2 dependent) but not the effects of IDO‐generated cytotoxic metabolites. These findings collectively suggest for the first time that high expression of protein IMPACT homolog in non‐immune cells such as skin cells acts as a protective mechanism against IDO‐induced GCN2 activation, therefore, makes them resistant to the amino acid‐deprived environment caused by IDO. J. Cell. Physiol. 225: 196–205, 2010. © 2010 Wiley‐Liss, Inc. 相似文献
16.
Babrzadeh F Jalili R Wang C Shokralla S Pierce S Robinson-Mosher A Nyren P Shafer RW Basso LC de Amorim HV de Oliveira AJ Davis RW Ronaghi M Gharizadeh B Stambuk BU 《Molecular genetics and genomics : MGG》2012,287(6):485-494
The Saccharomyces cerevisiae strains widely used for industrial fuel-ethanol production have been developed by selection, but their underlying beneficial genetic polymorphisms remain unknown. Here, we report the draft whole-genome sequence of the S. cerevisiae strain CAT-1, which is a dominant fuel-ethanol fermentative strain from the sugarcane industry in Brazil. Our results indicate that strain CAT-1 is a highly heterozygous diploid yeast strain, and the ~12-Mb genome of CAT-1, when compared with the reference S228c genome, contains ~36,000 homozygous and ~30,000 heterozygous single nucleotide polymorphisms, exhibiting an uneven distribution among chromosomes due to large genomic regions of loss of heterozygosity (LOH). In total, 58 % of the 6,652 predicted protein-coding genes of the CAT-1 genome constitute different alleles when compared with the genes present in the reference S288c genome. The CAT-1 genome contains a reduced number of transposable elements, as well as several gene deletions and duplications, especially at telomeric regions, some correlated with several of the physiological characteristics of this industrial fuel-ethanol strain. Phylogenetic analyses revealed that some genes were likely associated with traits important for bioethanol production. Identifying and characterizing the allelic variations controlling traits relevant to industrial fermentation should provide the basis for a forward genetics approach for developing better fermenting yeast strains. 相似文献
17.
Mahdi Jalili Tom Gebhardt Olaf Wolkenhauer Ali Salehzadeh-Yazdi 《生物化学与生物物理学报:疾病的分子基础》2018,1864(6):2349-2359
Decoding health and disease phenotypes is one of the fundamental objectives in biomedicine. Whereas high-throughput omics approaches are available, it is evident that any single omics approach might not be adequate to capture the complexity of phenotypes. Therefore, integrated multi-omics approaches have been used to unravel genotype–phenotype relationships such as global regulatory mechanisms and complex metabolic networks in different eukaryotic organisms. Some of the progress and challenges associated with integrated omics studies have been reviewed previously in comprehensive studies. In this work, we highlight and review the progress, challenges and advantages associated with emerging approaches, integrating gene expression and protein-protein interaction networks to unravel network-based functional features. This includes identifying disease related genes, gene prioritization, clustering protein interactions, developing the modules, extract active subnetworks and static protein complexes or dynamic/temporal protein complexes. We also discuss how these approaches contribute to our understanding of the biology of complex traits and diseases. This article is part of a Special Issue entitled: Cardiac adaptations to obesity, diabetes and insulin resistance, edited by Professors Jan F.C. Glatz, Jason R.B. Dyck and Christine Des Rosiers. 相似文献
18.
19.
Hasan Jalili Seyed H. Razavi Mohammad Safari F. Xavier Malcata 《Enzyme and microbial technology》2009,45(6-7):469-476
The behavior of Bifidobacterium animalis subsp. lactis Bb 12 under batch cultivation, after continuous culturing for up to 12 d, was monitored in skim milk-based media. Previous continuous culture for longer than 6 d affected the physiology of said microorganism. The minimum inhibitory concentrations of lactic and acetic acids increased from 18 to 26 g/l, whereas the molar ratio of acetic to lactic acid increased from 0.8 to 1.55, when the previous continuous culture increased its duration from 1 to 12 d. The specific lactose consumption rate decreased from 0.94 to 0.77 glactose/gcell dry mass/h within the batch culture timeframe; this was concomitant with greater amounts of acetic and formic acids, and lower amounts of lactic acid produced. The β-galactosidase activity increased as continuous culturing time increased, and reached 446 units/ml by 12 d; however, the rate of enzyme synthesis decreased concomitantly. Succinic acid was produced during the exponential growth and stationary phases of the batch culture, but the former at exponential growth phase was higher as the continuous culturing time was longer. For comparison purposes, batch cultivation of samples taken from continuous cultures by 1 and 12 d was done using a semi-synthetic medium with glucose as carbon source; a pattern similar to that observed when using skim milk-based media was observed. 相似文献
20.
Wearable hip protectors (padded garments) represent a promising strategy to decrease impact force and hip fracture risk during falls, and a wide range of products are currently marketed. However, little is known about how design features of hip protectors influence biomechanical effectiveness. We used a mechanical test system (simulating sideways falls) to measure the attenuation in femoral neck force provided by 26 commercially available hip protectors at three impact velocities (2, 3, and 4m/s). We also used a materials testing machine to characterize the force-deflection properties of each device. Regression analyses were performed to determine which geometric (e.g., height, width, thickness, volume) and force-deflection properties were associated with force attenuation. At an impact velocity of 3m/s, the force attenuation provided by the various hip protectors ranged between 2.5% and 40%. Hip protectors with lower stiffness (measured at 500N) provided greater force attenuation at all velocities. Protectors that absorbed more energy demonstrated greater force attenuation at the higher impact velocities (3 and 4m/s conditions), while protectors that did not directly contact (but instead bridged) the skin overlying the greater trochanter attenuated more force at velocities of 2 and 3m/s. At these lower velocities, the force attenuation provided by protectors that contacted the skin overlying the greater trochanter increased with increasing pad width, thickness, and energy dissipation. By providing a comparison of the protective value of a large range of existing hip protectors, these results can help to guide consumers and researchers in selecting hip protectors, and in interpreting the results of previous clinical trials. Furthermore, by determining geometric and material parameters that influence biomechanical performance, our results should assist manufacturers in designing devices that offer improved performance and clinical effectiveness. 相似文献