Alopecia, neurological defects, and endocrinopathy syndrome caused by decreased expression of RBM28, a nucleolar protein associated with ribosome biogenesis

Single-gene disorders offer unique opportunities to shed light upon fundamental physiological processes in humans. We investigated an autosomal-recessive phenotype characterized by alopecia, progressive neurological defects, and endocrinopathy (ANE syndrome). By using homozygosity mapping and candidate-gene analysis, we identified a loss-of-function mutation in RBM28, encoding a nucleolar protein. RBM28 yeast ortholog, Nop4p, was previously found to regulate ribosome biogenesis. Accordingly, electron microscopy revealed marked ribosome depletion and structural abnormalities of the rough endoplasmic reticulum in patient cells, ascribing ANE syndrome to the restricted group of inherited disorders associated with ribosomal dysfunction.     

Biofilm development of the polyethylene-degrading bacterium Rhodococcus ruber

We have recently isolated a biofilm-producing strain (C208) of Rhodococcus ruber that degraded polyethylene at a rate of 0.86% per week (r ²=0.98). Strain C208 adheres to polyethylene immediately upon exposure to the polyolefin. This initial biofilm differentiates (in a stepwise process that lasts about 20 h) into cell-aggregation-forming microcolonies. Further organization yields “mushroom-like” three-dimensional structures on the mature biofilm. The ratio between the population densities of the biofilm and the planktonic C208 cells after 10 days of incubation was about 60:1, indicating a high preference for the biofilm mode of growth. Analysis of extracellular polymeric substances (EPS) in the biofilm of C208 revealed that the polysaccharides level was up to 2.5 folds higher than that of the protein. The biofilm showed a high viability even after 60 days of incubation, apparently due to polyethylene biodegradation.     

Interpreting principal components in biomechanics: Representative extremes and single component reconstruction

Principal component analysis is a powerful tool in biomechanics for reducing complex multivariate datasets to a subset of important parameters. However, interpreting the biomechanical meaning of these parameters can be a subjective process. Biomechanical interpretations that are based on visual inspection of extreme 5th and 95th percentile waveforms may be confounded when extreme waveforms express more than one biomechanical feature. This study compares interpretation of principal components using representative extremes with a recently developed method, called single component reconstruction, which provides an uncontaminated visualization of each individual biomechanical feature. Example datasets from knee joint moments, lateral gastrocnemius EMG, and lumbar spine kinematics are used to demonstrate that the representative extremes method and single component reconstruction can yield equivalent interpretations of principal components. However, single component reconstruction interpretation cannot be contaminated by other components, which may enhance the use and understanding of principal component analysis within the biomechanics community.     

Structural insights of Staphylococcus aureus FtsZ inhibitors through molecular docking, 3D-QSAR and molecular dynamics simulations

Filamentous temperature-sensitive protein Z (FtsZ) is a protein encoded by the FtsZ gene that assembles into a Z-ring at the future site of the septum of bacterial cell division. Structurally, FtsZ is a homolog of eukaryotic tubulin but has low sequence similarity; this makes it possible to obtain FtsZ inhibitors without affecting the eukaryotic cell division. Computational studies were performed on a series of substituted 3-arylalkoxybenzamide derivatives reported as inhibitors of FtsZ activity in Staphylococcus aureus. Quantitative structure-activity relationship models (QSAR) models generated showed good statistical reliability, which is evident from r²_ncv and r²_loo values. The predictive ability of these models was determined and an acceptable predictive correlation (r²_Pred) values were obtained. Finally, we performed molecular dynamics simulations in order to examine the stability of protein-ligand interactions. This facilitated us to compare free binding energies of cocrystal ligand and newly designed molecule B1. The good concordance between the docking results and comparative molecular field analysis (CoMFA)/comparative molecular similarity indices analysis (CoMSIA) contour maps afforded obliging clues for the rational modification of molecules to design more potent FtsZ inhibitors.     

Improved visualization of the immunoreactive hypothalamo-neurohypophysial system by use of immuno-gold techniques

Summary Ultrastructural post-embedding immuno-gold techniques were applied to the supraoptic nucleus and the neurohypophysis of mice and rats. The primary antibodies were three different monoclonal antineurophysins, used in protein A-gold and immunoglobulin-gold procedures. Conventional plastic embedding as well as hydrophilic media (L.R. White) were used; non-osmicated and osmicated tissues were immunolabeled; sodium metaperiodate oxidation was used, but was not essential for immunolabeling.Vasopressinergic and oxytocinergic NSGs were identified by the specific immunoreactivity of their respective neurophysins on adjacent thin sections, and by sequential double labeling on the same thin section using two different antibodies associated with gold probes of different diameters. The immunoidentification indicates that vasopressin NSGs can additionally be differentiated as larger, with more electron-dense matrix, and susceptible to damage by sodium metaperiodate.The only organelles consistently labeled were neurosecretory granules (NSGs), either intact or within lysosomal configurations. Some lysosomal dense bodies were immunoreactive even when discrete NSGs were no longer morphologically recognisable within them. Labeled NSGs were located within neuronal cell bodies, along axonal shafts and within axonal swellings and endings; occasionally immunoreactive NSGs were observed within synaptic boutons. Labeling intensity was semi-quantitatively gauged by counting gold particles in relation to numbers of NSGs per axonal varicosity.The precise localisation achieved with particulate immunogold labeling surpasses that previously obtained with diffuse electron-dense immunoreaction products.     

Metal-dependent anaerobic methane oxidation in marine sediment: Insights from marine settings and other systems

Anaerobic oxidation of methane(AOM) plays a crucial role in controlling global methane emission. This is a microbial process that relies on the reduction of external electron acceptors such as sulfate, nitrate/nitrite, and transient metal ions. In marine settings, the dominant electron acceptor for AOM is sulfate, while other known electron acceptors are transient metal ions such as iron and manganese oxides. Despite the AOM process coupled with sulfate reduction being relatively well characterized,researches on metal-dependent AOM process are few, and no microorganism has to date been identified as being responsible for this reaction in natural marine environments. In this review, geochemical evidences of metal-dependent AOM from sediment cores in various marine environments are summarized. Studies have showed that iron and manganese are reduced in accordance with methane oxidation in seeps or diffusive profiles below the methanogenesis zone. The potential biochemical basis and mechanisms for metal-dependent AOM processes are here presented and discussed. Future research will shed light on the microbes involved in this process and also on the molecular basis of the electron transfer between these microbes and metals in natural marine environments.     

Colorimetric detection of in situ metal acetates and fluorides by a bipyridyl‐linked Schiff base

Here, we present a new bipyridyl moiety linked Schiff base (bipy‐1) that is well characterized using spectroscopic techniques. Colorimetric and UV‐vis titrations were used to study the photophysical properties of bipy‐1 in the presence of various tetrabutyl ammonium salt of anions and metal salts containing different counter cations. bipy‐1 showed selective recognition of dimethyl sulphoxide solution of tetrabutyl ammonium salt of F^? ion accompanied with a UV‐vis band at 529 nm and interesting binding of aqueous Co, Ni, and Cu acetates/fluorides, as confirmed by distinct color changes from fluorescent green to pink or orange and a strong band around 480–510 nm in the UV‐vis spectrum. However, in the presence of Co, Ni, and Cu countercations, any form of metal acetate/fluorides was found to be able to respond to similar color changes from fluorescent green to pink or orange, showing a band around 480–510 nm. This type of output clearly indicates that the in situ formation of Co, Ni, and Cu acetates/fluorides also coordinates with bipyridyl nitrogen atoms. Copyright © 2014 John Wiley & Sons, Ltd.     

It's All in Your Mind: Determining Germ Cell Fate by Neuronal IRE-1 in C. elegans

The C. elegans germline is pluripotent and mitotic, similar to self-renewing mammalian tissues. Apoptosis is triggered as part of the normal oogenesis program, and is increased in response to various stresses. Here, we examined the effect of endoplasmic reticulum (ER) stress on apoptosis in the C. elegans germline. We demonstrate that pharmacological or genetic induction of ER stress enhances germline apoptosis. This process is mediated by the ER stress response sensor IRE-1, but is independent of its canonical downstream target XBP-1. We further demonstrate that ire-1-dependent apoptosis in the germline requires both CEP-1/p53 and the same canonical apoptotic genes as DNA damage-induced germline apoptosis. Strikingly, we find that activation of ire-1, specifically in the ASI neurons, but not in germ cells, is sufficient to induce apoptosis in the germline. This implies that ER stress related germline apoptosis can be determined at the organism level, and is a result of active IRE-1 signaling in neurons. Altogether, our findings uncover ire-1 as a novel cell non-autonomous regulator of germ cell apoptosis, linking ER homeostasis in sensory neurons and germ cell fate.     

Potential involvement of F0F1-ATP(synth)ase and reactive oxygen species in apoptosis induction by the antineoplastic agent erucylphosphohomocholine in glioblastoma cell lines

Erucylphosphohomocholine (ErPC3, Erufosine?) was reported previously to induce apoptosis in otherwise highly apoptosis-resistant malignant glioma cell lines while sparing their non-tumorigenic counterparts. We also previously found that the mitochondrial 18 kDa Translocator Protein (TSPO) is required for apoptosis induction by ErPC3. These previous studies also suggested involvement of reactive oxygen species (ROS). In the present study we further investigated the potential involvement of ROS generation, the participation of the mitochondrial respiration chain, and the role of the mitochondrial F_OF₁-ATP(synth)ase in the pro-apoptotic effects of ErPC3 on U87MG and U118MG human glioblastoma cell lines. For this purpose, cells were treated with the ROS chelator butylated hydroxyanisole (BHA), the mitochondrial respiration chain inhibitors rotenone, antimycin A, myxothiazol, and the uncoupler CCCP. Also oligomycin and piceatannol were studied as inhibitors of the F_O and F₁ subunits of the mitochondrial F_OF₁-ATP(synth)ase, respectively. BHA was able to attenuate apoptosis induction by ErPC3, including mitochondrial ROS generation as determined with cardiolipin oxidation, as well as collapse of the mitochondrial membrane potential (Δψ_m). Similarly, we found that oligomycin attenuated apoptosis and collapse of the Δψ_m, normally induced by ErPC3, including the accompanying reductions in cellular ATP levels. Other inhibitors of the mitochondrial respiration chain, as well as piceatannol, did not show such effects. Consequently, our findings strongly point to a role for the F_O subunit of the mitochondrial F_OF₁-ATP(synth)ase in ErPC3-induced apoptosis and dissipation of Δψ_m as well as ROS generation by ErPC3 and TSPO.