Hydrogen photo-production by mixotrophic cultivation of chlamydomonas reinhardtii: Interaction between organic carbon and nitrogen

Hydrogen photo-production by a wild type and two engineered strains of Chlamydomonas reinhardtii was investigated. Growth rate values and hydrogen yields attained as the concentration of acetate and nitrogen vary were compared. In the analysis of microalgal growth, the interaction between organic carbon (acetate) and nitrogen (nitrate) was investigated by recourse to an experimental factorial design. This analysis evidenced the existence of a statistically significant interaction between organic carbon and nitrate. Hydrogen production was attained by cultivating microalgae previously grown in mixotrophic regime with sulphur deprived medium. The influence of varying the photobioreactor headspace on hydrogen production was investigated. This analysis revealed an increase in the hydrogen produced per unit volume of culture of about one order of magnitude when the headspace volume is modified from 100 to 350 mL. This result provides valuable indications on how to design and operate photobioreactors for hydrogen production optimization and was thoroughly discussed in terms of the metabolic pathways activated by sulphur depletion. ©2014, AIDIC Servizi S.r.l

The endothelin A receptor and epidermal growth factor receptor signaling converge on β-catenin to promote ovarian cancer metastasis

Aims: Endothelin A receptor (ETAR) and epidermal growth factor receptor (EGFR) cross-talk enhances the metastatic potential of epithelial ovarian cancer (EOC) cells activating different pathways, including β-catenin signalling. Here, we evaluated β-catenin as one of ETAR/EGFR downstream pathway in the invasive behaviour of EOC cells and their therapeutic potential to co-target ETAR and EGFR. Main methods: The phosphorylation status and interactions of different proteins were analysed by immunoblotting and immunoprecipitation. Reporter activity and RT-PCR was used for evaluation of β-catenin transcriptional activity and gene expression. Functional effects were evaluated by gelatin zymography and cell invasion assays. An orthotopic model of metastatic human EOC in mice was used for in vivo studies. Key findings: In EOC cell lines, ET-1 induced Src-dependent EGFR transactivation, causing tyrosine (Y) phosphorylation of β-catenin at the residue Y654, its dissociation from E-cadherin complexes and the accumulation as an active form. This pool of Tyr-β-catenin relocalised to the nucleus promoting its transcriptional activity, and the expression of its target genes, such as MMP-2. At functional level, ET-1 and EGFR circuits enhanced protease activity and cell invasion. All these effects were significantly inhibited by the ETAR antagonist, zibotentan, or EGFR inhibitor, gefitinib, and are completely blocked by co-addition of both drugs. In vivo, zibotentan treatment significantly inhibited metastases, associated with reduced expression and activation of MMPs and active β-catenin, especially when combined with gefitinib. Significance: Altogether these findings provide additional support to the potential use of ETAR and EGFR blockade as a new therapeutic opportunity for EOC treatment. © 2012 Elsevier Inc

Malleability of the self: electrophysiological correlates of the enfacement illusion

Self-face representation is fundamentally important for self-identity and self-consciousness. Given its role in preserving identity over time, self-face processing is considered as a robust and stable process. Yet, recent studies indicate that simple psychophysics manipulations may change how we process our own face. Specifically, experiencing tactile facial stimulation while seeing similar synchronous stimuli delivered to the face of another individual seen as in a mirror, induces 'enfacement' illusion, i.e. the subjective experience of ownership of the other’s face and a bias in attributing to the self, facial features of the other person. Here we recorded visual Event-Related Potentials elicited by the presentation of self, other and morphed faces during a self-other discrimination task performed immediately after participants received synchronous and control asynchronous Interpersonal Multisensory Stimulation (IMS). We found that self-face presentation after synchronous as compared to asynchronous stimulation significantly reduced the late positive potential (LPP; 450-750 ms), a reliable electrophysiological marker of self-identification processes. Additionally, enfacement cancelled out the differences in LPP amplitudes produced by self- and other-face during the control condition. These findings represent the first direct neurophysiological evidence that enfacement may affect self-face processing and pave the way to novel paradigms for exploring defective self-representation and self-other interactions

Nuclear β-arrestin1 is a critical cofactor of hypoxia-inducible factor-1α signaling in endothelin-1-induced ovarian tumor progression

Hypoxia-inducible factor-1α (HIF-1α) mediates the response to hypoxia or other stimuli, such as growth factors, including endothelin-1 (ET-1), to promote malignant progression in numerous tumors. The importance of cofactors that regulate HIF-1α signalling within tumor is not well understood. Here we elucidate that ET-1/ET(A) receptor (ET(A)R)-induced pathway physically and functionally couples the scaffold protein β-arrestin1 (β-arr1) to HIF-1α signalling. In epithelial ovarian cancer (EOC) cells, ET-1/ET(A)R axis induced vascular-endothelial growth factor (VEGF) expression through HIF-1α nuclear accumulation. In these cells, activation of ET(A)R by ET-1, by mimicking hypoxia, promoted the nuclear interaction between β-arr1 and HIF-1α and the recruitment of p300 acetyltransferase to hypoxia response elements on the target gene promoters, resulting in enhanced histone acetylation, and HIF-1α target gene transcription. Indeed, β-arr1-HIF-1α interaction regulated the enhanced expression and release of downstream targets, such as ET-1 and VEGF, required for tumor cell invasion and pro-angiogenic effects in endothelial cells. These effects were abrogated by β-arr1 or HIF-1α silencing or by pharmacological treatment with the dual ET-1 receptor antagonist macitentan. Interestingly, ET(A)R/β-arr1 promoted the self-amplifying HIF-1α-mediated transcription of ET-1 that sustained a regulatory circuit involved in invasive and angiogenic behaviors. In a murine orthotopic model of metastatic human EOC, treatment with macitentan, or silencing of β-arr1, inhibits intravasation and metastasis formation. Collectively, these findings reveal the interplay of β-arr1 with HIF-1α in the complexity of ET-1/ET(A)R signalling, mediating epigenetic modifications directly involved in the metastatic process, and suggest that targeting ET-1-dependent β-arr1/HIF-1α pathway by using macitentan may impair EOC progression

β-Arrestin 1 is required for endothelin-1-induced NF-κB activation in ovarian cancer cells

Aims In epithelial ovarian cancer (EOC), activation of endothelin-1 (ET-1)/endothelin A receptor (ETAR) signalling is linked to many tumor promoting effects, such as proliferation, angiogenesis, invasion and metastasis. These effects are dependent by the activation of critical signalling pathways, such as MAPK, Akt, and β-catenin, through specific cytosolic and nuclear scaffolding functions of β-arrestin 1 (β-arr1). Here, we have assessed the potential role of ET-1/ETAR in promoting NF-κB signalling in EOC cells through β-arr-1 recruitment. Main methods We used cultured HEY EOC cells cultured in the presence or absence of ET-1 and the ETAR antagonist BQ123. The phosphorylation of p65 and Iκ-Bα was evaluated by immunoblotting analysis. The interaction between p65 and β-arr1 was evaluated by immunoprecipitation experiments in nuclear extracts. NF-κB promoter activity was evaluated by transfection with NF-κB-driven luciferase reporter construct. Assessment of the function of β-arr1 was achieved by β-arr1 silencing with shRNA and expression of β-arr1-FLAG expression vector. Key findings In EOC cells, ET-1 promotes the phosphorylation of p65 subunit and the cytoplasmic inhibitor IκB that in turn led to increased NF-κB transcriptional activity. These effects were inhibited by the use of BQ123, as well as by β-arr-1 silencing, suggesting that ET-1 through ETAR promotes the recruitment of β-arr1 to regulate NF-κB signalling. Moreover, the nuclear physical interaction between p65 and β-arr1 indicates a nuclear function of β-arr-1 in ETAR-driven NF-κB transcriptional activity. Significance Altogether these findings reveal a previously unrecognized pathway that depends on β-arr1 to sustain NF-κB signalling in response to ETAR activation in ovarian cancer

Magnetic Resonance Imaging of the Hips of Runners Before and After their First Marathon Run: Does it Lead to Acute Changes?

BACKGROUND: No studies have focused on magnetic resonance imaging (MRI) of the hips of marathoners, despite the popularity and injury risks of marathon running. PURPOSE: To understand the effect of preparing for and completing a marathon run (42 km) on runners’ hip joints by comparing MRI findings before and after their first marathon. Study Design: Case-control study; Level of evidence, 3. METHODS: A total of 28 healthy adults (14 males, 14 females; mean age, 32.4 years) were recruited after registering for their first marathon. They underwent 3-T MRI of both hips at 16 weeks before (time point 1) and 2 weeks after the marathon (time point 2). After the first MRI, 21 runners completed the standardized, 4 month--long training program and the marathon; 7 runners did not complete the training or the marathon. Specialist musculoskeletal radiologists reported and graded the hip joint structures using validated scoring systems. Participants completed the Hip disability and Osteoarthritis Outcome Score (HOOS) at both imaging time points. RESULTS: At time point 1, MRI abnormalities of the hip joint were seen in 90% of participants and were located in at least 1 of these areas: labrum (29%), articular cartilage (7%), subchondral bone marrow (14%), tendons (17%), ligaments (14%), and muscles (31% had moderate muscle atrophy). At time point 2, only 2 of the 42 hips showed new findings: a small area of mild bone marrow edema appearance (nonweightbearing area of the hip and not attributable to running). There was no significant difference in HOOS between the 2 time points. Only 1 participant did not finish the training because of hip symptoms and thus did not run the marathon; however, symptoms resolved before the MRI at time point 2. Six other participants discontinued their training because of non–hip related issues: a knee injury, skin disease, a family bereavement, Achilles tendon injury, illness unrelated to training, and a foot injury unrelated to training. CONCLUSION: Runners who completed a 4-month beginner training program before their first marathon run, plus the race itself, showed no hip damage on 3-T MRI scans

Education Capability: A Focus on Gender and Science

The focus of the paper is on the measurement of science education capability with a gender perspective and in the capability approach framework. Measuring science education capability implies going beyond the measurement of children test scores. In the capability approach, we aim at the real opportunities that children can develop later in life and therefore it is important to include some measures of non-cognitive skills. We utilize, therefore, different indicators in addition to test scores in science: enjoyment in science, interest in science, general and personal values of science, self-confidence in performing science related tasks, awareness and perception of environmental issues, and responsibility for sustainable development. We utilize the 2006 PISA survey for Italian 15 year old children because it contains a particular focus on science and we estimate a Structural Equation Model to take into account that capabilities are latent constructs of which we only observe some indicators. We also investigate the determinants of children\u2019s science education capability in Italy taking into account household, individual and school factors. Results confirm that boys outperform girls in science education capability. Our theoretical construct for the science education capability confirms that all the indicators are relevant to measure this capability. School activities to promote sciences improve girls\u2019 capability and interactive methods of teaching improve both girls and boys capability. The household educational resources and the household educational possession are also positively correlated with girls\u2019 and boys\u2019 science education capability

Going Beyond Test Scores: The Gender Gap in Italian Children's Mathematical Capability

This paper investigates the relationship between gender, attitudes, and test scores in mathematics. The study argues that measures of children’s capability in mathematics must include some indicators of attitudes toward the subject. These are particularly important when analyzing gender gaps because attitudes toward mathematics differ by gender. To this end, the study first analyzes the gender gap in attitudes and test scores separately using school fixed effects models. Second, it estimates a structural equation model, which takes into account that mathematical capability is a latent construct for which some indicators (test scores and attitudes) are observed. Using data from the Italian National Institute for the Evaluation of Education Systems (INVALSI) for school years 5 and 10 in 2014 and 2015, results confirm that when mathematics capability, including both attitudes and test scores, is measured, the gap between boys and girls changes, and it is therefore relevant to consider both concepts