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1.
In the budding yeast Saccharomyces cerevisiae, mutations in the essential gene CDC1 cause defects in Golgi inheritance and actin polarization. However, the biochemical function of Cdc1p is unknown. Previous work showed that cdc1 mutants accumulate intracellular Ca(2+) and display enhanced sensitivity to the extracellular Mn(2+) concentration, suggesting that Cdc1p might regulate divalent cation homeostasis. By contrast, our data indicate that Cdc1p is a Mn(2+)-dependent protein that can affect Ca(2+) levels. We identified a cdc1 allele that activates Ca(2+) signaling but does not show enhanced sensitivity to the Mn(2+) concentration. Furthermore, our studies show that Cdc1p is an endoplasmic reticulum-localized transmembrane protein with a putative phosphoesterase domain facing the lumen. cdc1 mutant cells accumulate an unidentified phospholipid, suggesting that Cdc1p may be a lipid phosphatase. Previous work showed that deletion of the plasma membrane Ca(2+) channel Cch1p partially suppressed the cdc1 growth phenotype, and we find that deletion of Cch1p also suppresses the Golgi inheritance and actin polarization phenotypes. The combined data fit a model in which the cdc1 mutant phenotypes result from accumulation of a phosphorylated lipid that activates Ca(2+) signaling. 相似文献
2.
William K. Ridgeway Effrosyni Seitaridou Rob Phillips James R. Williamson 《Nucleic acids research》2009,37(21):e142
Microfluidic chips can automate biochemical assays on the nanoliter scale, which is of considerable utility for RNA–protein binding reactions that would otherwise require large quantities of proteins. Unfortunately, complex reactions involving multiple reactants cannot be prepared in current microfluidic mixer designs, nor is investigation of long-time scale reactions possible. Here, a microfluidic ‘Riboreactor’ has been designed and constructed to facilitate the study of kinetics of RNA–protein complex formation over long time scales. With computer automation, the reactor can prepare binding reactions from any combination of eight reagents, and is optimized to monitor long reaction times. By integrating a two-photon microscope into the microfluidic platform, 5-nl reactions can be observed for longer than 1000 s with single-molecule sensitivity and negligible photobleaching. Using the Riboreactor, RNA–protein binding reactions with a fragment of the bacterial 30S ribosome were prepared in a fully automated fashion and binding rates were consistent with rates obtained from conventional assays. The microfluidic chip successfully combines automation, low sample consumption, ultra-sensitive fluorescence detection and a high degree of reproducibility. The chip should be able to probe complex reaction networks describing the assembly of large multicomponent RNPs such as the ribosome. 相似文献
3.
Pedro de Atauri Míriam Tarrado-Castellarnau Josep Tarrag-Celada Carles Foguet Effrosyni Karakitsou Josep Joan Centelles Marta Cascante 《PLoS computational biology》2021,17(7)
Metabolic adaptations to complex perturbations, like the response to pharmacological treatments in multifactorial diseases such as cancer, can be described through measurements of part of the fluxes and concentrations at the systemic level and individual transporter and enzyme activities at the molecular level. In the framework of Metabolic Control Analysis (MCA), ensembles of linear constraints can be built integrating these measurements at both systemic and molecular levels, which are expressed as relative differences or changes produced in the metabolic adaptation. Here, combining MCA with Linear Programming, an efficient computational strategy is developed to infer additional non-measured changes at the molecular level that are required to satisfy these constraints. An application of this strategy is illustrated by using a set of fluxes, concentrations, and differentially expressed genes that characterize the response to cyclin-dependent kinases 4 and 6 inhibition in colon cancer cells. Decreases and increases in transporter and enzyme individual activities required to reprogram the measured changes in fluxes and concentrations are compared with down-regulated and up-regulated metabolic genes to unveil those that are key molecular drivers of the metabolic response. 相似文献
4.
Nike Bharucha Yang Liu Effrosyni Papanikou Conor McMahon Masatoshi Esaki Philip D. Jeffrey Frederick M. Hughson Benjamin S. Glick 《Molecular biology of the cell》2013,24(21):3406-3419
During the budding of coat protein complex II (COPII) vesicles from transitional endoplasmic reticulum (tER) sites, Sec16 has been proposed to play two distinct roles: negatively regulating COPII turnover and organizing COPII assembly at tER sites. We tested these ideas using the yeast Pichia pastoris. Redistribution of Sec16 to the cytosol accelerates tER dynamics, supporting a negative regulatory role for Sec16. To evaluate a possible COPII organization role, we dissected the functional regions of Sec16. The central conserved domain, which had been implicated in coordinating COPII assembly, is actually dispensable for normal tER structure. An upstream conserved region (UCR) localizes Sec16 to tER sites. The UCR binds COPII components, and removal of COPII from tER sites also removes Sec16, indicating that COPII recruits Sec16 rather than the other way around. We propose that Sec16 does not in fact organize COPII. Instead, regulation of COPII turnover can account for the influence of Sec16 on tER sites. 相似文献
5.
Differentiation between responses of primary productivity and phosphorus exploitation to species richness 总被引:1,自引:0,他引:1
Effrosyni D. Karanika Demetrios A. Alifragis Andreas P. Mamolos Demetrios S. Veresoglou 《Plant and Soil》2007,297(1-2):69-81
Several studies have shown that ecosystem functioning increases with increasing species richness. Most of these studies examined
the effects of species richness on primary productivity. The underlying mechanism that explains this pattern is usually the
selection effect. The higher the diversity in plant communities the higher the chance in including a very productive species
that dominates the community, or a legume species that brings N into the soil. Less attention has been given so far to the
effects of species richness on phosphorus exploitation. The aim of this work was to investigate the effect of species richness
on aboveground primary productivity and P accumulation in a plant diversity experiment. For this reason, 14 grassland plant
species were grown in containers as monocultures and in mixtures of 2-, 3-, 4-, 8-, 11- and 14-species combinations. Results
show that the aboveground phytomass and total P increased with increasing species richness. Complementarity effects, probably
through partitioning of resources, were most apparent in the highest levels of species richness, and were observed to be greater
for total P in comparison to phytomass. Selection effects generally were greater for phytomass than for total P; they were
significantly positive at the 2- to 8-species combinations but close to 0 or negative in the highest levels of species richness.
The increases in phytomass and total P at the highest levels of species richness appeared to be caused by the increased performance
of intermediate-productive species.
Responsible Editor: Tibor Kalapos. 相似文献
6.
Eleni Koufali Olga K. Voulgari reas P. Mamolos Effrosyni D. Karanika Demetrios S. Veresoglou 《Journal of Plant Ecology》2016,9(6):784
Aims Nitrogen (N) and phosphorus (P) constitute essential elements for plant growth and their availability influence species diversity in herbaceous plant communities. Legumes exhibit relatively high abundance in N-limited soils. Moreover, the legumes' N:P ratios are much higher than those of the other plant species grown in the same site, probably because they are able to fix atmospheric N 2. The objective of this study was to determine how the relative proportion in N and P availability and the restriction of legumes to fix atmospheric N 2 affect: (i) the primary productivity of plant species, (ii) species composition and (iii) N and P concentrations of species.Methods In an outdoor experiment, mixtures containing grasses, legumes and non-legume forbs were established in 32 containers under four soil treatments (control, N addition, P addition and disinfected soil), in a completely randomized design with eight replicates. Plant growth was examined when N and P were limited in the control soil:sand mixture, in a pot experiment sown with Plantago lanceolata .Important findings The pot experiment indicated that both N and P were limiting for the growth of P. lanceolata. Soil treatments affected primary productivity and species composition. Legumes had a relatively high abundance in the control and their growth was favoured, especially that of Medicago sativa, by P addition. Grasses' growth was increased by the addition of N. Inhibition of rhizobia resulted in poor growth of legumes and concomitant higher growth of grasses, in comparison to the control. The N:P ratios of non-legume species differed between treatments and were always higher in the legume species, even in the disinfected soil. The latter provides evidence that the high N concentrations found in legumes are a physiological characteristic of this specific group of plants. 相似文献
7.
Kyriaki G. Cholidou Ioannis D. Kostakis Effrosyni D. Manali Despina Perrea Alexandra Margeli Konstantinos Vougas Evangelos Markozannes Nikolaos Koulouris Manos Alchanatis 《Cytokine》2013,61(3):917-923
IntroductionIncreased levels of inflammatory mediators, such as hs-CRP, have been detected in patients with obstructive sleep apnea (OSA) and used as cardiovascular risk and disease outcome predictors. Calprotectin is an inflammatory marker regulating atherogenic processes not investigated in adult OSA patients. The aim of the present study as primary objective was to examine the role of calprotectin as an inflammatory molecule, acting through a distinct pathway to the atherogenic process in adult OSA patients and its associations with hs-CRP and the lipidemic profile of the patients. As a secondary objective was the evaluation of the atherogenic markers post-CPAP treatment.Materials and methodsSeventy-four participants underwent full overnight polysomnography. Blood samples were collected for calprotectin, hs-CRP, total cholesterol, triglycerides, LDL, HDL and glucose levels. Thirty-two OSA patients were reexamined 6 months post-CPAP treatment.ResultsOut of 74 participants included in the study, 33 had moderate OSA, 27 had severe OSA and 14 were controls. Calprotectin and hs-CRP were significantly increased in patients with moderate and severe OSA compared to controls (p < 0.0001). Calprotectin and hs-CRP levels were positively correlated with apnea-hypopnea index, BMI and total time of sleep with SaO2 <90% and inversely correlated with SaO2 minimum and mean values. Calprotectin and hs-CRP levels were significantly improved post-CPAP treatment (p < 0.0001).DiscussionCalprotectin may serve as a novel and reliable, biomarker of cardiovascular risk severity in OSA patients. The decrease of calprotectin levels post-CPAP treatment combined with hs-CRP amelioration could provide evidence for reduction of cardiovascular risk post CPAP treatment. 相似文献
8.
All cells must traffic proteins across their membranes. This essential process is responsible for the biogenesis of membranes and cell walls, motility and nutrient scavenging and uptake, and is also involved in pathogenesis and symbiosis. The translocase is an impressively dynamic nanomachine that is the central component which catalyses transmembrane crossing. This complex, multi-stage reaction involves a cascade of inter- and intramolecular interactions that select, sort and target polypeptides to the membrane, and use energy to promote the movement of these polypeptides across--or their lateral escape and integration into--the phospholipid bilayer, with high fidelity and efficiency. Here, we review the most recent data on the structure and function of the translocase nanomachine. 相似文献
9.
Angeliki?Balasopoulou Biljana?Stankovi? Angeliki?Panagiotara Gordana?Nik?evic Brock?A.?Peters Anne?John Effrosyni?Mendrinou Apostolos?Stratopoulos Aigli?Ioanna?Legaki Vasiliki?Stathakopoulou Aristoniki?Tsolia Nikolaos?Govaris Sofia?Govari Zoi?Zagoriti Konstantinos?Poulas Maria?Kanariou Nikki?Constantinidou Maro?Krini Kleopatra?Spanou Nedeljko?Radlovic Bassam?R.?Ali Joseph?Borg Radoje?Drmanac George?Chrousos Sonja?Pavlovic Eleftheria?Roma Branka?Zukic George?P.?Patrinos Theodora?KatsilaEmail author 《Human genomics》2016,10(1):34
Background
Celiac disease is a complex chronic immune-mediated disorder of the small intestine. Today, the pathobiology of the disease is unclear, perplexing differential diagnosis, patient stratification, and decision-making in the clinic.Methods
Herein, we adopted a next-generation sequencing approach in a celiac disease trio of Greek descent to identify all genomic variants with the potential of celiac disease predisposition.Results
Analysis revealed six genomic variants of prime interest: SLC9A4 c.1919G>A, KIAA1109 c.2933T>C and c.4268_4269delCCinsTA, HoxB6 c.668C>A, HoxD12 c.418G>A, and NCK2 c.745_746delAAinsG, from which NCK2 c.745_746delAAinsG is novel. Data validation in pediatric celiac disease patients of Greek (n?=?109) and Serbian (n?=?73) descent and their healthy counterparts (n?=?111 and n?=?32, respectively) indicated that HoxD12 c.418G>A is more prevalent in celiac disease patients in the Serbian population (P?<?0.01), while NCK2 c.745_746delAAinsG is less prevalent in celiac disease patients rather than healthy individuals of Greek descent (P?=?0.03). SLC9A4 c.1919G>A and KIAA1109 c.2933T>C and c.4268_4269delCCinsTA were more abundant in patients; nevertheless, they failed to show statistical significance.Conclusions
The next-generation sequencing-based family genomics approach described herein may serve as a paradigm towards the identification of novel functional variants with the aim of understanding complex disease pathobiology.10.
Effrosyni D Manali Charalampos Moschos Christina Triantafillidou Anastasia Kotanidou Ioannis Psallidas Sophia P Karabela Charis Roussos Spyridon Papiris Apostolos Armaganidis Georgios T Stathopoulos Nikolaos A Maniatis 《BMC pulmonary medicine》2011,11(1):1-13