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991.
992.
993.
Altered Clock Gene Expression in Obese Visceral Adipose Tissue Is Associated with Metabolic Syndrome
Elaine Vieira Elena G. Ruano Ana Lucia C. Figueroa Gloria Aranda Dulce Momblan Francesc Carmona Ramon Gomis Josep Vidal Felicia A. Hanzu 《PloS one》2014,9(11)
Clock gene expression was associated with different components of metabolic syndrome (MS) in human adipose tissue. However, no study has been done to compare the expression of clock genes in visceral adipose tissue (VAT) from lean and obese subjects and its clinical implications. Therefore, we studied in lean and obese women the endogenous 24 h expression of clock genes in isolated adipocytes and its association with MS components. VAT was obtained from lean (BMI 21–25 kg/m2; n = 21) and morbidly obese women (BMI >40 kg/m2; n = 28). The 24 h pattern of clock genes was analyzed every 6 hours using RT-PCR. Correlation of clinical data was studied by Spearman analysis. The 24 h pattern of clock genes showed that obesity alters the expression of CLOCK, BMAL1, PER1, CRY2 and REV-ERB ALPHA in adipocytes with changes found in CRY2 and REV-ERB ALPHA throughout the 24 h period. The same results were confirmed in VAT and stromal cells (SC) showing an upregulation of CRY2 and REV-ERB ALPHA from obese women. A positive correlation was observed for REV-ERB ALPHA gene expression with BMI and waist circumference in the obese population. Expression of ROR ALPHA was correlated with HDL levels and CLOCK with LDL. Obese subjects with MS exhibited positive correlation in the PER2 gene with LDL cholesterol, whereas REV-ERB ALPHA was correlated with waist circumference. We identified CRY2 and REV-ERB ALPHA as the clock genes upregulated in obesity during the 24 h period and that REV-ERB ALPHA is an important gene associated with MS. 相似文献
994.
Species traits and abundance influence the organization of liana–tree antagonistic interaction 下载免费PDF全文
Julia C. Sfair Veridiana de L. Weiser Fernando R. Martins Mariana M. Vidal Paulo R. Guimarães Jr 《Austral ecology》2018,43(2):236-241
The interaction among species can be influenced by neutral processes, in which more abundant species have high effect on the structure of interaction, or can be influenced by trait matching. Despite both variables (abundance and species traits) influencing the interaction of species in mutualistic networks, few studies showed their importance in antagonistic networks. Here, we posed the question: what are the main predictors of the liana–tree interactions: species abundance, biological traits or both? In a savanna woodland fragment in south‐eastern Brazil, we sampled lianas and trees in 1 ha, where we recorded the abundance, maximum height and bark roughness of tree species, as well as abundance, maximum diameter and climbing system of liana species. For each species, we calculated their contribution to nestedness (ni), which is a measure of network structure, and performed simple linear regressions between ni and abundance and species traits. Abundant species contribute more to ni than rare species, indicating that neutral processes affect interactions between lianas and trees, probably because lianas are opportunistic and climb trees in their neighbourhood. The only trait related to ni was tree height, which can indicate that light availability can have a considerable role on network structure between both growth forms. Therefore, the importance of species abundance and tree height can be related to opportunism of lianas on climbing the most suitable tree in their neighbourhood. 相似文献
995.
Lidia Osuna Jean-N?el Pierre María-Cruz González Rosario Alvarez Francisco J. Cejudo Cristina Echevarría Jean Vidal 《Plant physiology》1999,119(2):511-520
Phosphoenolpyruvate
carboxylase (PEPC) activity was detected in aleurone-endosperm extracts
of barley (Hordeum vulgare) seeds during germination,
and specific anti-sorghum (Sorghum bicolor)
C4 PEPC polyclonal antibodies immunodecorated constitutive
103-kD and inducible 108-kD PEPC polypeptides in western analysis. The
103- and 108-kD polypeptides were radiolabeled in situ after imbibition
for up to 1.5 d in 32P-labeled inorganic phosphate. In
vitro phosphorylation by a Ca2+-independent PEPC protein
kinase (PK) in crude extracts enhanced the enzyme''s velocity and
decreased its sensitivity to l-malate at suboptimal pH and
[PEP]. Isolated aleurone cell protoplasts contained both
phosphorylated PEPC and a Ca2+-independent PEPC-PK that was
partially purified by affinity chromatography on blue dextran-agarose.
This PK activity was present in dry seeds, and PEPC phosphorylation in
situ during imbibition was not affected by the cytosolic
protein-synthesis inhibitor cycloheximide, by weak acids, or by various
pharmacological reagents that had proven to be effective blockers of
the light signal transduction chain and PEPC phosphorylation in
C4 mesophyll protoplasts. These collective data support the
hypothesis that this Ca2+-independent PEPC-PK was formed
during maturation of barley seeds and that its presumed underlying
signaling elements were no longer operative during germination.Higher-plant PEPC (EC 4.1.1.31) is subject to in vivo
phosphorylation of a regulatory Ser located in the N-terminal domain of
the protein. In vitro phosphorylation by a
Ca2+-independent, low-molecular-mass (30–39 kD)
PEPC-PK modulates PEPC regulation interactively by opposing metabolite
effectors (e.g. allosteric activation by Glc-6-P and feedback
inhibition by l-malate; Andreo et al., 1987), decreasing
significantly the extent of malate inhibition of the leaf enzyme
(Carter et al., 1991; Chollet et al., 1996; Vidal et al., 1996; Vidal
and Chollet, 1997). These metabolites control the rate of
phosphorylation of PEPC via an indirect target-protein effect (Wang and
Chollet, 1993; Echevarría et al., 1994; Vidal and Chollet,
1997).Several lines of evidence support the view that this protein-Ser/Thr
kinase is the physiologically relevant PEPC-PK (Li and Chollet, 1993;
Chollet et al., 1996; Vidal et al., 1996; Vidal and Chollet, 1997). The
presence and inducible nature of leaf PEPC-PK have been established
further in various C3, C4,
and CAM plant species (Chollet et al., 1996). In all cases, CHX proved
to be a potent inhibitor of this up-regulation process so that apparent
changes in the turnover rate of PEPC-PK itself or another, as yet
unknown, protein factor were invoked to account for this observation
(Carter et al., 1991; Jiao et al., 1991; Chollet et al., 1996).
Consistent with this proposal are recent findings about PEPC-PK from
leaves of C3, C4, and CAM
plants that determined activity levels of the enzyme to depend on
changes in the level of the corresponding translatable mRNA (Hartwell
et al., 1996).Using a cellular approach we previously showed in
sorghum (Sorghum bicolor) and hairy crabgrass
(Digitaria sanguinalis) that PEPC-PK is
up-regulated in C4 mesophyll cell protoplasts
following illumination in the presence of a weak base
(NH4Cl or methylamine; Pierre et al., 1992;
Giglioli-Guivarc''h et al., 1996), with a time course (1–2 h) similar
to that of the intact, illuminated sorghum (Bakrim et al., 1992) or
maize leaf (Echevarría et al., 1990). This light- and
weak-base-dependent process via a complex transduction chain is likely
to involve sequentially an increase in pHc, inositol
trisphosphate-gated Ca2+ channels of the
tonoplast, an increase in cytosolic Ca2+, a
Ca2+-dependent PK, and PEPC-PK.Considerably less is known about the up-regulation of PEPC-PK and
PEPC phosphorylation in nongreen tissues. A sorghum root PEPC-PK
purified on BDA was shown to phosphorylate in vitro both recombinant
C4 PEPC and the root
C3-like isoform, thereby decreasing the enzyme''s
malate sensitivity (Pacquit et al., 1993). PEPC from soybean root
nodules was phosphorylated in vitro and in vivo by an endogenous PK
(Schuller and Werner, 1993; Zhang et al., 1995; Zhang and Chollet,
1997). A Ca2+-independent nodule PEPC-PK
containing two active polypeptides (32–37 kD) catalyzed the
incorporation of phosphate on a Ser residue of the target enzyme and
was modulated by photosynthate transported from the shoots (Zhang and
Chollet, 1997). Regulatory seryl phosphorylation of a heterotetrameric
(α2β2) banana fruit
PEPC by a copurifying, Ca2+-independent PEPC-PK
was shown to occur in vitro (Law and Plaxton, 1997). Although
phosphorylation was also detected in vivo and found to concern
primarily the α-subunit, PEPC exists mainly in the dephosphorylated
form in preclimacteric, climacteric, and postclimacteric fruit.In a previous study we showed that PEPC undergoes regulatory
phosphorylation in aleurone-endosperm tissue during germination of
wheat seeds (Osuna et al., 1996). Here we report on PEPC and the
requisite PEPC-PK in germinating barley (Hordeum vulgare)
seeds. PEPC was highly phosphorylated by a
Ca2+-independent Ser/Thr PEPC-PK similar to that
found in other plant systems studied previously (Chollet et al., 1996);
however, the PK was already present in the dry seed and its activity
did not require protein synthesis during imbibition. 相似文献
996.
Fatty acid acylation of platelet proteins was studied by measuring incorporation of [3H]palmitate and [3H]myristate after incubation at 37 degrees C for 4 h. About ten major radiolabeled proteins were detected after SDS-polyacrylamide gel electrophoresis and fluorography, for both fatty acids. Cleavage by hydroxylamine treatment indicated an ester bond of either palmitate or myristate to these proteins. Nevertheless, a single 50 kDa peptide was specifically modified by an amide-linked myristate. The functions of acylated proteins in platelets are still unknown, but their relation with DLPC-induced shape changes and vesicle shedding is excluded. 相似文献
997.
Alka Mehra Aleena Zahra Victor Thompson Natalie Sirisaengtaksin Ashley Wells Maura Porto Stefan K?ster Kristen Penberthy Yoshihisha Kubota Amelie Dricot Daniel Rogan Marc Vidal David E. Hill Andrew J. Bean Jennifer A. Philips 《PLoS pathogens》2013,9(10)
Mycobacterium tuberculosis (Mtb) disrupts anti-microbial pathways of macrophages, cells that normally kill bacteria. Over 40 years ago, D''Arcy Hart showed that Mtb avoids delivery to lysosomes, but the molecular mechanisms that allow Mtb to elude lysosomal degradation are poorly understood. Specialized secretion systems are often used by bacterial pathogens to translocate effectors that target the host, and Mtb encodes type VII secretion systems (TSSSs) that enable mycobacteria to secrete proteins across their complex cell envelope; however, their cellular targets are unknown. Here, we describe a systematic strategy to identify bacterial virulence factors by looking for interactions between the Mtb secretome and host proteins using a high throughput, high stringency, yeast two-hybrid (Y2H) platform. Using this approach we identified an interaction between EsxH, which is secreted by the Esx-3 TSSS, and human hepatocyte growth factor-regulated tyrosine kinase substrate (Hgs/Hrs), a component of the endosomal sorting complex required for transport (ESCRT). ESCRT has a well-described role in directing proteins destined for lysosomal degradation into intraluminal vesicles (ILVs) of multivesicular bodies (MVBs), ensuring degradation of the sorted cargo upon MVB-lysosome fusion. Here, we show that ESCRT is required to deliver Mtb to the lysosome and to restrict intracellular bacterial growth. Further, EsxH, in complex with EsxG, disrupts ESCRT function and impairs phagosome maturation. Thus, we demonstrate a role for a TSSS and the host ESCRT machinery in one of the central features of tuberculosis pathogenesis. 相似文献
998.
White adipose tissue is the main site of energy storage, but it is now recognized as an active participant in regulating physiologic and pathologic processes including immunity and inflammation. It has an endocrine function by secreting at least two main hormones, leptin and adiponectin. It can secrete other products, named adipokines, including cytokines and chemokines, involved in inflammation process. The release of adipokines by either adipocytes or adipose tissue infiltrated macrophages lead to a chronic sub-inflammatory state that could play a central role in cardiovascular complications linked to obesity and insulin resistance, a risk factor to develop type-2 diabetes. 相似文献
999.
JW Mills ADC MacKnight JA Jarrell JM Dayer DA Ausiello 《The Journal of cell biology》1981,88(3):637-643
To determine the specificity and efficacy of [(3)H]ouabain binding as a quantitative measure of the Na(+) pump (Na(+), K(+)-ATPase) and as a marker for the localization of pumps involved in transepithelial Na(+)-transport, we analyzed the interaction of [(3)H]ouabain with its receptor in pig kidney epithelial (LLC-PK(1)) cells. When these epithelial cells are depleted of Na(+) and exposed to 2 muM [(3)H]ouabain in a Na(+)-free medium, binding is reduced by 90 percent. When depleted of K(+) and incubated in a K(+)- free medium, the ouabain binding rate is increase compared with that measured at 5 mM. This increase is only demonstable when Na(+) is present. The increased rate could be attributed to the predominance of the Na(+)-stimulated phosphorylated form of the pump, as K(+) is not readily available to stimulate dephosphorylation. However, some binding in the K(+)-free medium is attributable to pump turnover (and therefore, recycling of K(+)), because analysis of K(+)-washout kinetics demonstrated that addition of 2 muM ouabain to K(+)-depleted cells increased the rate of K(+) loss. These results indicate that in intact epithelial cells, unlike isolated membrane preparations, the most favorable condition for supporting ouabain binding occurs when the Na(+), K(+)-ATPase is operating in the Na(+)-pump mode or is phosphorylated in the presence of Na(+). When LLC-PK(1) cells were exposed to ouabain at 4 degrees C, binding was reduced by 97 percent. Upon rewarming, the rate of binding was greater than that obtained on cells kept at a constant 37 degrees C. However, even at this accelerated rate, the time to reach equilibrium was beyond what is required for cells, swollen by exposure to cold, to recover normal volume. Thus, results from studies that have attempted to use ouabain to eliminate the contribution of the conventional Na(+) pump to volume recovery must be reevaluated if the exposure to ouabain was done in the cold or under conditions in which the Na(+) pump is not operating. 相似文献
1000.
Vidal AE Kannouche P Podust VN Yang W Lehmann AR Woodgate R 《The Journal of biological chemistry》2004,279(46):48360-48368
Y-family DNA polymerases are believed to facilitate the replicative bypass of damaged DNA in a process commonly referred to as translesion synthesis. With the exception of DNA polymerase eta (poleta), which is defective in humans with the Xeroderma pigmentosum variant (XP-V) phenotype, little is known about the cellular function(s) of the remaining human Y-family DNA polymerases. We report here that an interaction between human DNA polymerase iota (poliota) and the proliferating cell nuclear antigen (PCNA) stimulates the processivity of poliota in a template-dependent manner in vitro. Mutations in one of the putative PCNA-binding motifs (PIP box) of poliota or the interdomain connector loop of PCNA diminish the binding between poliota and PCNA and concomitantly reduce PCNA-dependent stimulation of poliota activity. Furthermore, although retaining its capacity to interact with poleta in vivo, the poliota-PIP box mutant fails to accumulate in replication foci. Thus, PCNA, acting as both a scaffold and a modulator of the different activities involved in replication, appears to recruit and coordinate replicative and translesion DNA synthesis polymerases to ensure genome integrity. 相似文献