Since the first description of apoptosis four decades ago, great efforts have been made to elucidate, both in vivo and in vitro, the molecular mechanisms involved in its regulation. Although the role ...of cytochrome c during apoptosis is well established, relatively little is known about its participation in signaling pathways in vivo due to its essential role during respiration. To obtain a better understanding of the role of cytochrome c in the onset of apoptosis, we used a proteomic approach based on affinity chromatography with cytochrome c as bait in this study. In this approach, novel cytochrome c interaction partners were identified whose in vivo interaction and cellular localization were facilitated through bimolecular fluorescence complementation. Modeling of the complex interface between cytochrome c and its counterparts indicated the involvement of the surface surrounding the heme crevice of cytochrome c, in agreement with the vast majority of known redox adducts of cytochrome c. However, in contrast to the high turnover rate of the mitochondrial cytochrome c redox adducts, those occurring under apoptosis led to the formation of stable nucleo-cytoplasmic ensembles, as inferred mainly from surface plasmon resonance and nuclear magnetic resonance measurements, which permitted us to corroborate the formation of such complexes in vitro. The results obtained suggest that human cytochrome c interacts with pro-survival, anti-apoptotic proteins following its release into the cytoplasm. Thus, cytochrome c may interfere with cell survival pathways and unlock apoptosis in order to prevent the spatial and temporal coexistence of antagonist signals.
Iron limitation is the major factor controlling phytoplankton growth in vast regions of the contemporary oceans. In this study, a combination of thermoluminescence (TL), chlorophyll fluorescence, and ...P700 absorbance measurements have been used to elucidate the effects of iron deficiency in the photosynthetic electron transport of the marine diatom P. tricornutum. TL was used to determine the effects of iron deficiency on photosystem II (PSII) activity. Excitation of iron-replete P. tricornutum cells with single turn-over flashes induced the appearance of TL glow curves with two components with different peaks of temperature and contributions to the total signal intensity: the B band (23°C, 63%), and the AG band (40°C, 37%). Iron limitation did not significantly alter these bands, but induced a decrease of the total TL signal. Far red excitation did not increase the amount of the AG band in iron-limited cells, as observed for iron-replete cells. The effect of iron deficiency on the photosystem I (PSI) activity was also examined by measuring the changes in P700 redox state during illumination. The electron donation to PSI was substantially reduced in iron-deficient cells. This could be related with the important decline on cytochrome c 6 content observed in these cells. Iron deficiency also induced a marked increase in light sensitivity in P. tricornutum cells. A drastic increase in the level of peroxidation of chloroplast lipids was detected in iron-deficient cells even when grown under standard conditions at low light intensity. Illumination with a light intensity of 300 μE m(-2) s(-1) during different time periods caused a dramatic disappearance in TL signal in cells grown under low iron concentration, this treatment not affecting to the signal in iron-replete cells. The results of this work suggest that iron deficiency induces partial blocking of the electron transfer between PSII and PSI, due to a lower concentration of the electron donor cytochrome c 6. This decreased electron transfer may induce the over-reduction of the plastoquinone pool and consequently the appearance of acceptor side photoinhibition in PSII even at low light intensities. The functionality of chlororespiratory electron transfer pathway under iron restricted conditions is also discussed.
Background/objectives
Several studies showed lower serum 25-hydroxyvitamin D levels in patients with idiopathic restless legs syndrome (RLS) compared with matched controls, and a single study showed ...an association between the rs731236 single nucleotide polymorphism (SNP) in the
vitamin D receptor
(
VDR
) gene and the risk for RLS. We aimed to study the relationship between the serum 25-hydroxyvitamin D levels and to confirm previous findings related to SNPs in the
VDR
and the
GC vitamin D binding protein
(
GC
) gene, with the risk for RLS in the Spanish Caucasian population.
Methods
We genotyped 285 idiopathic RLS patients and 325 age and sex-matched controls for
VDR
rs2228750,
VDR
rs7975232,
VDR
rs739837,
VDR
rs78783628,
GC
rs7041 and
GC
rs4588 SNPs using TaqMan assays, and determined serum 25-hydroxyvitamin D levels in 111 idiopathic RLS patients and 167 controls using an ELISA commercial kit.
Results
Serum 25-hydroxyvitamin D levels were significantly higher in RLS patients than in controls but were unrelated with the 7 SNPs studied. None of the 7 SNPs analyzed was associated with the risk for idiopathic RLS or with a positive family history of RLS. However, RLS patients carrying the rs7975232CC genotype or the rs7975232C allele, had a higher frequency of response to GABAergic drugs. Associations between the age at onset and the severity of RLS with SNPs were inconsistent.
Conclusions
This study shows an association between increased serum concentrations of 25-hydroxyvitamin D and a lack of association between 7 SNPs in the
VDR
and in the
GC
genes with RLS in the Spanish Caucasian population.
The current scenario where the effects of global warming are more and more evident, has motivated different initiatives for facing this, such as the creation of global policies with a clear ...environmental guideline. Within these policies, the control of Greenhouse Gase (GHG) emissions has been defined as mandatory, but for carrying out this, a smart strategy is proposed. This is the application of a circular economy model, which seeks to minimize the generation of waste and maximize the efficient use of resources. From this point of view, CO2 recycling is an alternative to reduce emissions to the atmosphere, and we need to look for new business models which valorization this compound which now must be considered as a renewable carbon source. This has renewed the interest in known processes for the chemical transformation of CO2 but that have not been applied at industrial level because they do not offer evident profitability. For example, the methane produced in the Sabatier reaction has a great potential for application, but this depends on the existence of a sustainable supply of hydrogen and a greater efficiency during the process that allows maximizing energy efficiency and thermal control to maximize the methane yield. Regarding energy efficiency and thermal control of the process, the use of structured reactors is an appropriate strategy. The evolution of new technologies, such as 3D printing, and the consolidation of knowledge in the structing of catalysts has enabled the use of these reactors to develop a wide range of possibilities in the field. In this sense, the present review presents a brief description of the main policies that have motivated the transition to a circular economy model and within this, to CO2 recycling. This allows understanding, why efforts are being focused on the development of different reactions for CO2 valorization. Special attention to the case of the Sabatier reaction and in the application of structured reactors for such process is paid.
Background
The Diagnostic and Statistical Manual of Mental Disorders, version 5 (DSM‐5) definition of agoraphobia (AG) as an independent diagnostic entity makes it timely to re‐examine the ...epidemiology of AG. Study objective was to present representative data on the characteristics of individuals who meet
DSM‐IV criteria for AG (AG without a history of panic disorder PD and PD with AG) but not
DSM‐5 criteria,
DSM‐5 but not
DSM‐IV criteria, or both sets of criteria.
Methods
Population‐based surveys from the World Mental Health Survey Initiative including adult respondents (n = 136,357) from 27 countries across the world. The Composite International Diagnostic Interview was used to assess AG and other disorders.
Results
Lifetime and 12‐month prevalence estimates of DSM‐5 AG (1.5% and 1.0%) were comparable to
DSM‐IV (1.4% and 0.9%). Of respondents meeting criteria in either system, 57.1% met criteria in both, while 24.2% met criteria for
DSM‐5 only and 18.8% for
DSM‐IV only. Severe role impairment due to AG was reported by a lower proportion of respondents who met criteria only for
DSM‐IV AG (30.4%) than those with both
DSM‐5 and
DSM‐IV AG (44.0%;
χ
2
1 = 4.7;
P = 0.031). The proportion of cases with any comorbidity was lower among respondents who met criteria only for
DSM‐IV AG (78.7%) than those who met both sets (92.9%;
χ
2
1= 14.5;
P < 0.001).
Conclusions
This first large survey shows that, compared to the DSM‐IV, the
DSM‐5 identifies a substantial group of new cases with AG, while the prevalence rate remains stable at 1.5%. Severity and comorbidity are higher in individuals meeting
DSM‐5 AG criteria compared with individuals meeting
DSM‐IV AG criteria only.
The natural radioactivity in coal fly ash and natural pozzolan Portland cement samples produced in Spain was measured by gamma spectrometry. Activity concentrations of
226
Ra,
232
Th and
40
K ranged ...from 15.7 to 88.3 Bq kg
−1
, from 12.8 to 81.0 Bq kg
−1
and from 37.0 to 678.0 Bq kg
−1
, respectively. The radiological hazards samples owing to the mentioned natural radioactivity were inferred from determinations of the activity concentration index,
I
, absorbed dose rate,
D
ext
, and annual effective dose,
E
p
, which falls within 0.20 mSv to 0.87 mSv (coal-cement) and 0.18 mSv to 0.50 mSv (pozzolan-cement) (≤ 1 mSv, threshold criterion). Therefore, these cements are proper to be used for building purposes as result of their radiological assessment.
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•Alfalfa mosaic virus (AMV) and P12 plants can be used for the RSS screening.•The AMV-P12 RSS assay is simple, sensitive, rapid and quantitative.•The coat protein (CP) of carnation ...mottle virus (CarMV) is a RSS.•The CarMV CP blocks the accumulation of small RNAs.
Plant viruses express RNA silencing suppressor (RSS) proteins to counteract plant defence mechanisms. Here, we describe a method to assess the RSS activity based on an alfalfa mosaic virus (AMV) RNA 3 expression vector and transgenic Nicotiana tabacum plants that express the P1 and P2 subunits of the AMV replicase (P12 plants). Inoculation of P12 plants with different AMV RNA 3 constructs expressing different HC-Pro mutants that differ in their RSS capabilities, revealed a perfect correlation between necrotic lesions on inoculated leaves and RSS activity. Protoplast analysis showed that the RSS activity correlated with the accumulation of the AMV RNAs. A direct comparison between three RSS activity assays and the AMV-P12 system revealed that the coat protein of carnation mottle virus displays RSS activity with the four assays and reduced the accumulation of the siRNAs.
Fanconi Anemia (FA) is the most prevalent inherited bone marrow failure (BMF) syndrome. Nevertheless, the pathophysiological mechanisms of BMF in FA have not been fully elucidated. Since FA cells are ...defective in DNA repair, we hypothesized that FA hematopoietic stem and progenitor cells (HSPCs) might express DNA damage-associated stress molecules such as Natural Killer group 2 member D ligands (NKG2D-Ls). These ligands could then interact with the activating NKG2D receptor expressed in cytotoxic NK or CD8+ T cells which may result in progressive HSPCs depletion. Our results indeed demonstrated upregulated levels of NKG2D-Ls in cultured FA fibroblasts and T cells, which were further exacerbated by mitomycin C or formaldehyde. Notably, a high proportion of BM CD34+ HSPCs from FA patients also expressed increased levels of NKG2D-Ls, which correlated inversely with the percentage of CD34+ cells in BM. Remarkably, the reduced clonogenic potential characteristic of FA HSPCs was improved by blocking NKG2D/NKG2D-L interactions. Moreover, the in vivo blockage of these interactions in a BMF FA mouse model ameliorated the anemia in these animals. Our study demonstrates the involvement of NKG2D/NKG2D-L interactions in FA HSPC functionality, suggesting an unexpected role of the immune system in the progressive BMF characteristic of FA.
In the diatom Phaeodactylum tricornutum, iron limitation promotes a decrease in the content of photosystem II, as determined by measurements of oxygen-evolving activity, thermoluminescence, ...chlorophyll fluorescence analyses and protein quantification methods. Thermoluminescence experiments also indicate that iron limitation induces subtle changes in the energetics of the recombination reaction between reduced QB and the S2/S3 states of the water-splitting machinery. However, electron transfer from QA to QB, involving non-heme iron, seems not to be significantly inhibited. Moreover, iron deficiency promotes a severe decrease in the content of the extrinsic PsbV/cytochrome c550 subunit of photosystem II, which appears in eukaryotic algae from the red photosynthetic lineage (including diatoms) but is absent in green algae and plants. The decline in the content of cytochrome c550 under iron-limiting conditions is accompanied by a decrease in the binding of this protein to photosystem II, and also of the extrinsic PsbO subunit. We propose that the lack of cytochrome c550, induced by iron deficiency, specifically affects the binding of other extrinsic subunits of photosystem II, as previously described in cyanobacterial PsbV mutants.
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