Synthesis,characterization, and electrocatalytic behaviour of hydrothermally grown nanostructured La2O3 and La2O3/K-complex

Rare earth metals play a conspicuous role in magnetic resonance imaging (MRI) for detecting cancerous cells. The alkali metal potassium is a neurotransmitter in the sodium–potassium pump in biomedical sciences. This unique property of rare earth metals and potassium drew our attention to carry forward this study. Therefore, in this work, previously synthesized potassium (K) complexes formed by the reflux of 4-N,N-dimethylaminobenzoic acid (DBA) and potassium hydroxide in methanol, and named [(μ2–4-N,N-dimethylaminobenzoate-κO)(μ2–4-N,N-dimethylaminobenzoic acid-κO)(4-N,N-dimethylaminobenzoic acid-κO) potassium(I) coordination polymer)] were treated hydrothermally with La₂O₃ nanomaterials to obtain a nanohybrid La₂O₃/K-complex. After that, the K-complex was analyzed using single-crystal X-ray diffraction and ¹H and ¹³C NMR spectroscopy. In addition, the structural and morphological properties of the as-prepared nanostructured La₂O₃/K-complex were also characterized, which involved an investigation using X-ray diffraction (XRD)spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic force spectroscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. After this, the electrochemical redox behaviour of the synthesized nanohybrid material was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Therefore, the results from these studies revealed that the as-prepared material was a La₂O₃/K-complex that has a promising future role in sensing various analytes, as it showed effective electrocatalytic behaviour.     

Beyond ecosystem modeling: A roadmap to community cyberinfrastructure for ecological data‐model integration

In an era of rapid global change, our ability to understand and predict Earth's natural systems is lagging behind our ability to monitor and measure changes in the biosphere. Bottlenecks to informing models with observations have reduced our capacity to fully exploit the growing volume and variety of available data. Here, we take a critical look at the information infrastructure that connects ecosystem modeling and measurement efforts, and propose a roadmap to community cyberinfrastructure development that can reduce the divisions between empirical research and modeling and accelerate the pace of discovery. A new era of data‐model integration requires investment in accessible, scalable, and transparent tools that integrate the expertise of the whole community, including both modelers and empiricists. This roadmap focuses on five key opportunities for community tools: the underlying foundations of community cyberinfrastructure; data ingest; calibration of models to data; model‐data benchmarking; and data assimilation and ecological forecasting. This community‐driven approach is a key to meeting the pressing needs of science and society in the 21st century.     

ATPase‐driven oligomerization of RIG‐I on RNA allows optimal activation of type‐I interferon

The cytosolic pathogen sensor RIG‐I is activated by RNAs with exposed 5′‐triphosphate (5′‐ppp) and terminal double‐stranded structures, such as those that are generated during viral infection. RIG‐I has been shown to translocate on dsRNA in an ATP‐dependent manner. However, the precise role of the ATPase activity in RIG‐I activation remains unclear. Using in vitro‐transcribed Sendai virus defective interfering RNA as a model ligand, we show that RIG‐I oligomerizes on 5′‐ppp dsRNA in an ATP hydrolysis‐dependent and dsRNA length‐dependent manner, which correlates with the strength of type‐I interferon (IFN‐I) activation. These results establish a clear role for the ligand‐induced ATPase activity of RIG‐I in the stimulation of the IFN response.     

Etazolate rescues behavioral deficits in chronic unpredictable mild stress model: Modulation of hypothalamic–pituitary–adrenal axis activity and brain-derived neurotrophic factor level

Preliminary study in our laboratory showed that etazolate produced antidepressant- and anxiolytic-like effects in rodent models, however, the ability of etazolate to produce antidepressant- and anxiolytic-like effects and underlying mechanism(s) in chronic unpredictable mild stress (CUMS) model have not been adequately addressed. This study was aimed to investigate the beneficial effects of etazolate on CUMS-induced behavioral deficits (depression- and anxiety-like behaviors). In addition, the possible underlying mechanism(s) of etazolate in CUMS model was also investigated by measuring serum corticosterone (CORT) and brain-derived neurotrophic factor (BDNF) levels. Mice were subjected to a battery of stressors for 28 days. Etazolate (0.5 and 1 mg/kg, p.o.) and fluoxetine (20 mg/kg, p.o.) were administered during the last 21 days (8–28th) of the CUMS paradigm. The results showed that 4-weeks CUMS produces significant depression-like behavior in tail suspension test (TST) and partial anxiety-like behavior in elevated plus maze (EPM) and open field test (OFT). Stressed mice have also shown a significant high serum CORT and low BDNF level. Chronic treatment with etazolate (0.5 and 1 mg/kg., p.o.) and fluoxetine (20 mg/kg., p.o.) produced significant antidepressant-like behavior in TST (decreased duration of immobility), whereas, partial anxiolytic-like behavior in EPM (increased percentage of open arm entries) and OFT (increased % central ambulation score, total ambulation score and time spent in center zone). In addition, etazolate and fluoxetine treatment significantly (p < 0.05) increased the BDNF level and inhibited the hypothalamic–pituitary–adrenocortical (HPA) axis hyperactivity, as evidenced by low serum CORT level in stressed mice. In addition, etazolate and fluoxetine also showed significant antidepressant- and anxiolytic-like effects in normal control mice. In this study no significant changes were observed in locomotor activity in actophotometer test. Moreover, we did not find any effect of etazolate and fluoxetine on CORT and BDNF levels in normal control mice. In conclusion, the results of the present study suggested compelling evidences that etazolate has more marked effect on depression-like behavior in mice, which is atleast in part may be related to their modulating effects on the HPA axis and BDNF level.     

An Appended Domain Results in an Unusual Architecture for Malaria Parasite Tryptophanyl-tRNA Synthetase

Specific activation of amino acids by aminoacyl-tRNA synthetases (aaRSs) is essential for maintaining fidelity during protein translation. Here, we present crystal structure of malaria parasite Plasmodium falciparum tryptophanyl-tRNA synthetase (Pf-WRS) catalytic domain (AAD) at 2.6 Å resolution in complex with L-tryptophan. Confocal microscopy-based localization data suggest cytoplasmic residency of this protein. Pf-WRS has an unusual N-terminal extension of AlaX-like domain (AXD) along with linker regions which together seem vital for enzymatic activity and tRNA binding. Pf-WRS is not proteolytically processed in the parasites and therefore AXD likely provides tRNA binding capability rather than editing activity. The N-terminal domain containing AXD and linker region is monomeric and would result in an unusual overall architecture for Pf-WRS where the dimeric catalytic domains have monomeric AXDs on either side. Our PDB-wide comparative analyses of 47 WRS crystal structures also provide new mechanistic insights into this enzyme family in context conserved KMSKS loop conformations.     

Sensational placodes: Neurogenesis in the otic and olfactory systems

For both the intricate morphogenetic layout of the sensory cells in the ear and the elegantly radial arrangement of the sensory neurons in the nose, numerous signaling molecules and genetic determinants are required in concert to generate these specialized neuronal populations that help connect us to our environment. In this review, we outline many of the proteins and pathways that play essential roles in the differentiation of otic and olfactory neurons and their integration into their non-neuronal support structures. In both cases, well-known signaling pathways together with region-specific factors transform thickened ectodermal placodes into complex sense organs containing numerous, diverse neuronal subtypes. Olfactory and otic placodes, in combination with migratory neural crest stem cells, generate highly specialized subtypes of neuronal cells that sense sound, position and movement in space, odors and pheromones throughout our lives.     

N‐acetylcysteine counteracts oxidative stress and prevents hCG‐induced apoptosis in rat Leydig cells through down regulation of caspase‐8 and JNK

We have earlier reported that following persistent stimulation with hCG, oxidative stress‐induced apoptosis in rat Leydig cells was mainly achieved through the extrinsic pathway. In the present study, the role of N‐acetylcysteine (NAC) in counteracting the oxidative stress and the mechanisms of inhibition of apoptosis under such conditions were investigated. NAC (1 mM) intervention with repeated hCG stimulation (50 ng/ml, four times, each with 30 min challenge) prevented the decline in Leydig cell viability and the rise in lipid peroxidation and reactive oxygen species. Simultaneously, the activities of the enzymes glutathione‐S‐transferase, catalase, superoxide dismutase and the intracellular glutathione and antioxidant capacity of the treated cells improved significantly. Apoptotic markers Fas, FasL, and caspase‐8, up‐regulated following repeated hCG exposure, were significantly down‐regulated following NAC co‐incubation. While Bcl‐2 expression was fully restored, Bax and caspase‐9 remained unchanged. NAC treatment induced down‐regulation of upstream JNK/pJNK and down‐stream caspase‐3 in the target cells. Taken together, the above findings indicate that NAC counteracted the oxidative stress in Leydig cells induced as a result of repeated hCG stimulation, and inhibited apoptosis by mainly regulating the extrinsic and JNK pathways of metazoan apoptosis. Mol. Reprod. Dev. 77:900–909, 2010. © 2010 Wiley‐Liss, Inc.     

Complex prokaryotic genome structure: rapid evolution of chromosome II

Although many bacteria with two chromosomes have been sequenced, the roles of such complex genome structuring are still unclear. To uncover levels of chromosome I (CI) and chromosome II (CII) sequence divergence, Mauve 2.2.0 was used to align the CI- and CII-specific sequences of bacteria with complex genome structuring in two sets of comparisons: the first set was conducted among the CI and CII of bacterial strains of the same species, while the second set was conducted among the CI and CII of species in Alphaproteobacteria that possess two chromosomes. The analyses revealed a rapid evolution of CII-specific DNA sequences compared with CI-specific sequences in a majority of organisms. In addition, levels of protein divergence between CI-specific and CII-specific genes were determined using phylogenetic analyses and confirmed the DNA alignment findings. Analysis of synonymous and nonsynonymous substitutions revealed that the structural and functional constraints on CI and CII genes are not significantly different. Also, horizontal gene transfer estimates in selected organisms demonstrated that CII in many species has acquired higher levels of horizontally transferred segments than CI. In summary, rapid evolution of CII may perform particular roles for organisms such as aiding in adapting to specialized niches.