Comparative genome analysis of Solanum lycopersicum and Solanum tuberosum

Solanum lycopersicum and Solanum tuberosum are agriculturally important crop species as they are rich sources of starch, protein, antioxidants, lycopene, beta-carotene, vitamin C, and fiber. The genomes of S. lycopersicum and S. tuberosum are currently available. However the linear strings of nucleotides that together comprise a genome sequence are of limited significance by themselves. Computational and bioinformatics approaches can be used to exploit the genomes for fundamental research for improving their varieties. The comparative genome analysis, Pfam analysis of predicted reviewed paralogous proteins was performed. It was found that S. lycopersicum proteins belong to more families, domains and clans in comparison with S. tuberosum. It was also found that mostly intergenic regions are conserved in two genomes followed by exons, intron and UTR. This can be exploited to predict regions between genomes that are similar to each other and to study the evolutionary relationship between two genomes, leading towards the development of disease resistance, stress tolerance and improved varieties of tomato.     

Targeted elimination of peroxisome proliferator-activated receptor gamma in beta cells leads to abnormalities in islet mass without compromising glucose homeostasis

The nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPAR gamma) is an important regulator of lipid and glucose homeostasis and cellular differentiation. Studies of many cell types in vitro and in vivo have demonstrated that activation of PPAR gamma can reduce cellular proliferation. We show here that activation of PPAR gamma is sufficient to reduce the proliferation of cultured insulinoma cell lines. We created a model with mice in which the expression of the PPARG gene in beta cells was eliminated (beta gamma KO mice), and these mice were found to have significant islet hyperplasia on a chow diet. Interestingly, the normal expansion of beta-cell mass that occurs in control mice in response to high-fat feeding is markedly blunted in these animals. Despite this alteration in beta-cell mass, no effect on glucose homeostasis in beta gamma KO mice was noted. Additionally, while thiazolidinediones enhanced insulin secretion from cultured wild-type islets, administration of rosiglitazone to insulin-resistant control and beta gamma KO mice revealed that PPAR gamma in beta cells is not required for the antidiabetic actions of these compounds. These data demonstrate a critical physiological role for PPAR gamma function in beta-cell proliferation and also indicate that the mechanisms controlling beta-cell hyperplasia in obesity are different from those that regulate baseline cell mass in the islet.     

Moderate/subclinical calcium deficiency attenuates trabecular mass,microarchitecture and bone growth in growing rats

Adequate dietary calcium (Ca) intake is essential for bone accretion, peak bone mass (PBM) attainment, bone quality and strength during the mammalian growth period. Severe Ca deficiency during growing age results in secondary hyperparathyroidism (SHPT) and poor bone quality and strength. However, the impact of moderate Ca deficiency during rats early growth period on bone health and the reversibility with supplementing calcium later in adult life remains unclear. Female Sprague-Dawley (SD) rats (postnatal 28th day, P28) were initiated either with a moderate calcium-deficient diet (MCD, 0.25% w/w Ca) or a control diet (0.8% w/w Ca, control group) till P70. Thereafter, MCD rats were continued either with MCD diet or supplemented with calcium diet (0.8% w/w Ca, calcium supplemented group, CaS) till P150. Another group (control rats) were fed 0.8% w/w Ca containing diet from P28 till P150.MCD group, as compared to the control group, had significantly reduced serum ionized Ca and procollagen type 1 N-terminal propeptide (P1NP) at P70 while no significant change was observed in serum corrected Ca, inorganic phosphate (P), alkaline phosphatase (ALP), 25-hydroxy vitamin D [25(OH)D], intact parathyroid hormone (iPTH), and urinary C-terminal telopeptide of collagen 1 (CTX-1), Ca, and P. Femoral and tibial metaphysis in MCD rats had significantly reduced linear growth, cortical and trabecular volumetric BMD (vBMD), trabecular microarchitecture (BV/TV%, trabecular thickness, separation and number, structural model index and connectivity density), cortical thickness, and bone stiffness despite the absence of secondary hyperparathyroidism (SHPT). Continued MCD at P70–P150 results in persistence of compromised bone strength while calcium supplementation (CaS group) improved all the parameters related to bone strength and microarchitecture. Our results indicate that uncorrected moderate/subclinical calcium deficiency in growing rats can result in poor bone quality and strength despite the absence of SHPT. This finding could have relevance in children with poor calcium intake in childhood and adolescence.     

Comparison of two ferns (Adiantum capillus-veneris Linn. and Microsorium punctatum (Linn.) Copel) for their Cr accumulation potential and antioxidant responses

Study was undertaken to compare Cr accumulation in two ferns (Adiantum capillus-veneris Linn. and Microsorium punctatum (Linn.) Copel) and the role of antioxidants were also investigated towards metal tolerance in order to assess the use of ferns in phytomediation/ phytostabilization. Different concentrations (0, 50, 100, 150 microg g(-1) dw) of Cr were added to fern planted in pot containing 1 kg soil. In both the ferns, Cr accumulation increased with increase in metal concentration and maximum accumulation of 800.5 microg g(-1) (fronds) and 1457.4 microg g(-1) (roots) in M. punctatum and 660.8 microg g(-1) (fronds) and 1259.6 microg g(-1) (roots) in A. capillus-veneris was recorded. The increase in the levels of malondialdehyde, antioxidants and antioxidant enzymes (superoxide dismutase, glutathione peroxidase) in A. capillus-veneris was less pronounced than M. punctatum under Cr exposure as compared to their respective controls. In view of less decrease in chlorophyll content and antioxidants along with higher accumulation of Cr in the fronds M. punctatum, is indicative of its higher tolerance towards Cr. However, bioaccumulation factor (concentration of Cr in fronds/concentration of Cr in the soil) of both the ferns was recorded > 1 which qualifies the plants as potential Cr hyperaccumulator and suitable for phytoremediaton.     

Carbon‐Coated Li3Nd3W2O12: A High Power and Low‐Voltage Insertion Anode with Exceptional Cycleability for Li‐Ion Batteries

The synthesis of carbon‐coated Li₃Nd₃W₂O₁₂ (C‐Li₃Nd₃W₂O₁₂), a low voltage insertion anode (0.3 V vs. Li) for a Li‐ion battery, is reported to exhibit extraordinary performance. The low voltage reversible insertion provides an increase in the energy density of Li‐ion power packs. For instance, C‐Li₃Nd₃W₂O₁₂ delivered an energy density of ≈390 Wh kg^?1 (based on cathode mass loading) when coupled with an LiMn₂O₄ cathode with an operating potential of 3.4 V. Furthermore, excellent cycling profiles are observed for C‐Li₃Nd₃W₂O₁₂ anodes both in half and full‐cell configurations. The full‐cell is capable of delivering very stable cycling profiles at high current rates (e.g., 2 C), which clearly suggests the high power capability of such garnet‐type anodes.     

Modulation of synaptic potentials and cell excitability by dendritic K<Subscript>IR</Subscript> and K<Subscript>As</Subscript> channels in nucleus accumbens medium spiny neurons: A computational study

The nucleus accumbens (NAc), a critical structure of the brain reward circuit, is implicated in normal goal-directed behaviour and learning as well as pathological conditions like schizophrenia and addiction. Its major cellular substrates, the medium spiny (MS) neurons, possess a wide variety of dendritic active conductances that may modulate the excitatory post synaptic potentials (EPSPs) and cell excitability. We examine this issue using a biophysically detailed 189-compartment stylized model of the NAc MS neuron, incorporating all the known active conductances. We find that, of all the active channels, inward rectifying K⁺ (K_IR) channels play the primary role in modulating the resting membrane potential (RMP) and EPSPs in the down-state of the neuron. Reduction in the conductance of K_IR channels evokes facilitatory effects on EPSPs accompanied by rises in local input resistance and membrane time constant. At depolarized membrane potentials closer to up-state levels, the slowly inactivating A-type potassium channel (K_As) conductance also plays a strong role in determining synaptic potential parameters and cell excitability. We discuss the implications of our results for the regulation of accumbal MS neuron biophysics and synaptic integration by intrinsic factors and extrinsic agents such as dopamine.     

Hypoxia induced non-apoptotic cellular changes during aerenchyma formation in rice (Oryza sativa L.) roots

The stress of low oxygen concentrations in a waterlogged environment is minimized in some plants that produce aerenchyma, a tissue characterized by prominent intercellular spaces. It is produced by the predictable collapse of root cortex cells, indicating a programmed cell death (PCD) and facilitates gas diffusion between root and the aerial environment. The objective of this study was to characterize the cellular changes take place during aerenchyma formation in root of rice that accompany PCD. Scanning electron microscopy and transmission electron microscopy were used for cellular analysis of roots. Aerenchyma development was observed in both aerobic and flooded conditions. Structural changes in membranes and organelles were examined during development of root cortex cells to compare with previous examples of PCD. There was an initial collapse which started at a specific position in the mid cortex, indicating loss of turgor, and the cytoplasm became more electron dense. These cells were distinct in shape from those located towards the periphery. Mitochondria and endoplasmic reticulum appeared normal at this early stage though the tonoplast lost its integrity. Subsequently it underwent further degeneration while the plasmalemma retracted from the cell wall followed by death of neighboring cells followed a radial path. However, pycnosis of the nucleus, blebbing of plasma membrane and production of apoptotic bodies were not found which in turn indicated nonapoptotic PCD during aerenchyma formation in rice.