Chloroplast biogenesis of photosystem II cores involves a series of assembly-controlled steps that regulate translation

The biogenesis of photosystem II, one of the major photosynthetic protein complexes, involves a cascade of assembly-governed regulation of translation of its major chloroplast-encoded subunits. In Chlamydomonas reinhardtii, the presence of the reaction center subunit D2 is required for the expression of the other reaction center subunit D1, while the presence of D1 is required for the expression of the core antenna subunit apoCP47. Using chimeric genes expressed in the chloroplast, we demonstrate that the decreased synthesis of D1 or apoCP47 in the absence of protein assembly is due to a genuine downregulation of translation. This regulation is mediated by the 5' untranslated region of the corresponding mRNA and originates from negative feedback exerted by the unassembled D1 or apoCP47 polypeptide. However, autoregulation of translation of subunit D1 is not implicated in the recovery from photoinhibition, which involves an increased translation of psbA mRNA in response to the degradation of photodamaged D1. De novo synthesis and repair of photosystem II complexes are independently controlled.     

Full-thickeness anterior blepharotomy and transpalpebral fat decompression in Graves' orbitopathy

A chief morbidity of Graves eye disease is eyelid retraction and exophthalmus. Transpalpebral orbital fat removal accomplished with full thickness anterior blepharotomy was performed in 4 patients (5 orbits). Preoperative and postoperative ocular exposure symptoms, visual acuity, upper eyelid retraction and proptosis were evaluated. In all 5 operated orbits preoperative symptoms resolved; good results were achieved from the functional and cosmetic point of view. Full-thickness anterior blepharotomy combined with fat decompression is a safe and effective surgery for patients with upper eyelid retraction and exophthalmus due to enlarged orbital fat compartment.     

Evidence of involvement of leptin and IL-6 peptides in the action of interferon-beta in secondary progressive multiple sclerosis

Leptin is a peptide hormone which acts on cells of immune system by influencing the production of cytokines. Serum leptin levels and cytokine production by peripheral blood mononuclear cells (PBMC) were measured in 18 secondary progressive multiple sclerosis (SPMS) patients under IFN-beta-1b treatment. There were no overall effects on leptin, interleukin-6 (IL-6), IL-10 and IL-12 p40 after 2, 6 and 12 months of treatment. However, leptin and IL-6 decreased after 6 and 12 months of treatment in 12 patients who did not show progression of disability. Thus, our pilot data show that the beneficial effect of IFN-beta on some SPMS patients might be associated with the reduced levels of leptin and reduced IL-6 production by PBMC.     

Multiscale modeling of the cardiovascular system: application to the study of pulmonary and coronary perfusions in the univentricular circulation

The objective of this study is to compare the coronary and pulmonary blood flow dynamics resulting from two configurations of systemic-to-pulmonary artery shunts currently utilized during the Norwood procedure: the central (CS) and modified Blalock Taussig (MBTS) shunts. A lumped parameter model of the neonatal cardiovascular circulation and detailed 3-D models of the shunt based on the finite volume method were constructed. Shunt sizes of 3, 3.5 and 4 mm were considered. A multiscale approach was adopted to prescribe appropriate and realistic boundary conditions for the 3-D models of the Norwood circulation. Results showed that the average shunt flow rate is higher for the CS option than for the MBTS and that pulmonary flow increases with shunt size for both options. Cardiac output is higher for the CS option for all shunt sizes. Flow distribution between the left and the right pulmonary arteries is not completely balanced, although for the CS option the discrepancy is low (50-51% of the pulmonary flow to the right lung) while for the MBTS it is more pronounced with larger shunt sizes (51-54% to the left lung). The CS option favors perfusion to the right lung while the MBTS favors the left. In the CS option, a smaller percentage of aortic flow is distributed to the coronary circulation, while that percentage rises for the MBTS. These findings may have important implications for coronary blood flow and ventricular function.     

Evidence for a constitutive cytoplasmic cutinase in ungerminated conidia of Botrytis cinerea Pers.: Fr.

Cytoplasmic soluble proteins from ungerminated conidia of Botrytis cinerea exhibited cutinase activity, while cell wall binding proteins lacked this activity. Cutinase activity in proteins extracted from cell walls and cytoplasm of ungerminated conidia of Botrytis cinerea was determined using p-nitrophenyl butyrate (PNB) and TLC analysis of products derived from hydrolysis of [³H]cutin. Treatment of conidia with indoxyl acetate, a substrate indicative of non-specific esterase and cutinase activity, also gave a positive reaction in the cytoplasm of ungerminated conidia. The possible role of a putative constitutive cutinase in the cytoplasm of conidia in the early stages of infection of plants by B. cinerea is discussed.     

The targeting of plasmalemmal ceramide to mitochondria during apoptosis

Ceramide is a key lipid mediator of cellular processes such as differentiation, proliferation, growth arrest and apoptosis. During apoptosis, ceramide is produced within the plasma membrane. Although recent data suggest that the generation of intracellular ceramide increases mitochondrial permeability, the source of mitochondrial ceramide remains unknown. Here, we determine whether a stress-mediated plasmalemmal pool of ceramide might become available to the mitochondria of apoptotic cells. We have previously established annexin A1--a member of a family of Ca(2+) and membrane-binding proteins--to be a marker of ceramide platforms. Using fluorescently tagged annexin A1, we show that, upon its generation within the plasma membrane, ceramide self-associates into platforms that subsequently invaginate and fuse with mitochondria. An accumulation of ceramide within the mitochondria of apoptotic cells was also confirmed using a ceramide-specific antibody. Electron microscopic tomography confirmed that upon the formation of ceramide platforms, the invaginated regions of the plasma membrane extend deep into the cytoplasm forming direct physical contacts with mitochondrial outer membranes. Ceramide might thus be directly transferred from the plasma membrane to the mitochondrial outer membrane. It is conceivable that this "kiss-of-death" increases the permeability of the mitochondrial outer membrane thereby triggering apoptosis.     

The French National Registry of patients with Facioscapulohumeral muscular dystrophy

Background

Facioscapulohumeral muscular dystrophy is a rare inherited neuromuscular disease with an estimated prevalence of 1/20,000 and France therefore harbors about 3000 FSHD patients. With research progress and the development of targeted therapies, patients’ identification through registries can facilitate and improve recruitment in clinical trials and studies.

Results

The French National Registry of FSHD patients was designed as a mixed model registry involving both patients and physicians, through self-report and clinical evaluation questionnaires respectively, to collect molecular and clinical data. Because of the limited number of patients, data quality is a major goal of the registry and various automatic data control features have been implemented in the bioinformatics system. In parallel, data are manually validated by molecular and clinical curators. Since its creation in 2013, data from 638 FSHD patients have been collected, representing about 21% of the French FSHD population. The mixed model strategy allowed to collect 59.1% of data from both patients and clinicians; 26 and 14.9% from respectively patients and clinicians only. With the identification of the FSHD1 and FSHD2 forms, specific questionnaires have been designed. Though FSHD2 patients are progressively included, FSHD1 patients still account for the majority (94.9%). The registry is compatible with the FAIR principles as data are Findable, Accessible and Interoperable. We thus used molecular standards and standardized clinical terms used by the FILNEMUS French network of reference centers for the diagnosis and follow-up of patients suffering from a rare neuromuscular disease. The implemented clinical terms mostly map to dictionaries and terminology systems such as SNOMED-CT (75% of terms), CTV3 (61.7%) and NCIt (53.3%). Because of the sensitive nature of data, they are not directly reusable and can only be accessed as aggregated data after evaluation and approval by the registry oversight committee.

Conclusions

The French National Registry of FSHD patients belongs to a national effort to develop databases, which should now interact with other initiatives to build a European and/or an international FSHD virtual registry for the benefits of patients. It is accessible at www.fshd.fr and various useful information, links, and documents, including a video, are available for patients and professionals.

     

Multidrug-resistance (MDR) phenotype of human osteosarcoma cells evaluated by quantitative morphological and electron microscopy analyses

Summary— Multidrug-resistant (MDR) variants of a human osteosarcoma cell line (U-2 OS) have been recently obtained by continuous exposure to doxorubicin (DX). The growth and phenotypic characteristics of these cell lines have been demonstrated to be related to the level of expression of P-glycoprotein. In this work, the morphological changes associated with MDR have been evaluated by quantitative image analysis and transmission electron microscopy. Resistant cells present morphological changes with respect to sensitive cells at both cytoplasmic and nuclear level. Some of these changes appear to be related to the degree of resistance but not to the direct presence of DX, since deprived cells maintain some modified characters, while others are partly lost. These findings suggest that DX exposure affects cell metabolism causing progressive changes of the cell morphotype.     

Disentangling extrinsic from intrinsic factors in disease dynamics: a nonlinear time series approach with an application to cholera

Alternative explanations for disease and other population cycles typically include extrinsic environmental drivers, such as climate variability, and intrinsic nonlinear dynamics resulting from feedbacks within the system, such as species interactions and density dependence. Because these different factors can interact in nonlinear systems and can give rise to oscillations whose frequencies differ from those of extrinsic drivers, it is difficult to identify their respective contributions from temporal population patterns. In the case of disease, immunity is an important intrinsic factor. However, for many diseases, such as cholera, for which immunity is temporary, the duration and decay pattern of immunity is not well known. We present a nonlinear time series model with two related objectives: the reconstruction of immunity patterns from data on cases and population sizes and the identification of the respective roles of extrinsic and intrinsic factors in the dynamics. Extrinsic factors here include both seasonality and long-term changes or interannual variability in forcing. Results with simulated data show that this semiparametric method successfully recovers the decay of immunity and identifies the origin of interannual variability. An application to historical cholera data indicates that temporary immunity can be long-lasting and decays in approximately 9 yr. Extrinsic forcing of transmissibility is identified to have a strong seasonal component along with a long-term decrease. Furthermore, noise appears to sustain the multiple frequencies in the long-term dynamics. Similar semiparametric models should apply to population data other than for disease.     

Novel surface expression of reticulocalbin 1 on bone endothelial cells and human prostate cancer cells is regulated by TNF-alpha

An unbiased cDNA expression phage library derived from bone-marrow endothelial cells was used to identify novel surface adhesion molecules that might participate in metastasis. Herein we report that reticulocalbin 1 (RCN1) is a cell surface-associated protein on both endothelial (EC) and prostate cancer (PCa) cell lines. RCN1 is an H/KDEL protein with six EF-hand, calcium-binding motifs, found in the endoplasmic reticulum. Our data indicate that RCN1 also is expressed on the cell surface of several endothelial cell lines, including human dermal microvascular endothelial cells (HDMVECs), bone marrow endothelial cells (BMEC), and transformed human bone marrow endothelial cells (TrHBMEC). While RCN1 protein levels were highest in lysates from HDMVEC, this difference was not statistically significant compared BMEC and TrHBMEC. Given preferential adhesion of PCa to bone-marrow EC, these data suggest that RCN1 is unlikely to account for the preferential metastasis of PCa to bone. In addition, there was not a statistically significant difference in total RCN1 protein expression among the PCa cell lines. RCN1 also was expressed on the surface of several PCa cell lines, including those of the LNCaP human PCa progression model and the highly metastatic PC-3 cell line. Interestingly, RCN1 expression on the cell surface was upregulated by tumor necrosis factor alpha treatment of bone-marrow endothelial cells. Taken together, we show cell surface localization of RCN1 that has not been described previously for either PCa or BMEC and that the surface expression on BMEC is regulated by pro-inflammatory TNF-alpha.