Mapping-by-Sequencing Identifies HvPHYTOCHROME C as a Candidate Gene for the early maturity 5 Locus Modulating the Circadian Clock and Photoperiodic Flowering in Barley

Phytochromes play an important role in light signaling and photoperiodic control of flowering time in plants. Here we propose that the red/far-red light photoreceptor HvPHYTOCHROME C (HvPHYC), carrying a mutation in a conserved region of the GAF domain, is a candidate underlying the early maturity 5 locus in barley (Hordeum vulgare L.). We fine mapped the gene using a mapping-by-sequencing approach applied on the whole-exome capture data from bulked early flowering segregants derived from a backcross of the Bowman(eam5) introgression line. We demonstrate that eam5 disrupts circadian expression of clock genes. Moreover, it interacts with the major photoperiod response gene Ppd-H1 to accelerate flowering under noninductive short days. Our results suggest that HvPHYC participates in transmission of light signals to the circadian clock and thus modulates light-dependent processes such as photoperiodic regulation of flowering.     

Experimental zygomycosis in rabbits: Clinicopathological studies

Zygomycosis was produced experimentally in 20 New Zealand white rabbits (Oryctolagus cuniculus) by intra-nasal administration of spores of Absidia corymbifera. Infected animals showed dullness, depression, coughing and mucopurulent nasal discharge, but no mortality. Haematology revealed no significant change in Hb and PCV, but leukocytosis due to neutrophilia in the initial stages of the experiment. There was a significant increase in serum total proteins, creatinine, AST, ALT, total Igs and CICs. A. corymbifera specific IgM and IgG antibodies were detected in the sera of the infected animals. Gross lesions consisted of pneumonic consolidations of the antero-ventral lobes of the lungs. Microscopically, histology showed formation of pyogranulommas in the lungs. Fungal elements typical of A. corymbifera were demonstrated in the tissues upto 15 days after infection by special stains and confirmed by indirect immunoperoxidase. Re-isolation of the fungus from lungs was also achieved consistently up to 15 days only. It was concluded that intra-nasal instillation of A. corymbifera in rabbits produced significant clinico-pathological alterations with the lesions confined mainly to the lungs. In the present study, neither systemic dissemination of the disease occurred nor were kidneys site of predilection as reported earlier. This revised version was published online in August 2006 with corrections to the Cover Date.     

Modeling amyloid beta-peptide insertion into lipid bilayers

Inspired by recent suggestions that the Alzheimer's amyloid beta peptide (Abeta) can insert into cell membranes and form harmful ion channels, we model insertion of the 40- and 42-residue forms of the peptide into cell membranes using a Monte Carlo code which is specific at the amino acid level. We examine insertion of the regular Abeta peptide as well as mutants causing familial Alzheimer's disease, and find that all but one of the mutants change the insertion behavior by causing the peptide to spend more simulation steps in only one leaflet of the bilayer. We also find that Abeta42, because of the extra hydrophobic residues relative to Abeta40, is more likely to adopt this conformation than Abeta40 in both wild-type and mutant forms. We argue qualitatively why these effects happen. Here, we present our results and develop the hypothesis that this partial insertion increases the probability of harmful channel formation. This hypothesis can partly explain why these mutations are neurotoxic simply due to peptide insertion behavior. We further apply this model to various artificial Abeta mutants which have been examined experimentally, and offer testable experimental predictions contrasting the roles of aggregation and insertion with regard to toxicity of Abeta mutants. These can be used through further experiments to test our hypothesis.     

Truthful online double auction based dynamic resource provisioning for multi-objective trade-offs in IaaS clouds

Auction designs have recently been adopted for static and dynamic resource provisioning in IaaS clouds, such as Microsoft Azure and Amazon EC2. However, the existing mechanisms are mostly restricted to simple auctions, single-objective, offline setting, one-sided interactions either among cloud users or cloud service providers (CSPs), and possible misreports of cloud user’s private information. This paper proposes a more realistic scenario of online auctioning for IaaS clouds, with the unique characteristics of elasticity for time-varying arrival of cloud user requests under the time-based server maintenance in cloud data centers. We propose an online truthful double auction technique for balancing the multi-objective trade-offs between energy, revenue, and performance in IaaS clouds, consisting of a weighted bipartite matching based winning-bid determination algorithm for resource allocation and a Vickrey–Clarke–Groves (VCG) driven algorithm for payment calculation of winning bids. Through rigorous theoretical analysis and extensive trace-driven simulation studies exploiting Google cluster workload traces, we demonstrate that our mechanism significantly improves the performance while promising truthfulness, heterogeneity, economic efficiency, individual rationality, and has a polynomial-time computational complexity.

     

Enhanced prostacyclin formation and Wnt signaling in sclerostin deficient osteocytes and bone

We show that prostacyclin production is increased in bone and osteocytes from sclerostin (Sost) knockout mice which have greatly increased bone mass. The addition of prostacyclin or a prostacyclin analog to bone forming osteoblasts enhances differentiation and matrix mineralization of osteoblasts. The increase in prostacyclin synthesis is linked to increases in β-catenin concentrations and activity as shown by enhanced binding of lymphoid enhancer factor, Lef1, to promoter elements within the prostacyclin synthase promoter. Blockade of Wnt signaling reduces prostacyclin production in osteocytes. Increased prostacyclin production by osteocytes from sclerostin deficient mice could potentially contribute to the increased bone formation seen in this condition.     

Establishment and characterization of an epithelial cell line from thymus of Catla catla (Hamilton, 1822)

A cell line, CTE, derived from catla (Catla catla) thymus has been established by explant method and subcultured for more than 70 passages over a period of 400 days. The cell line has been maintained in L-15 (Leibovitz) medium supplemented with 10% fetal bovine serum. CTE cell line consists of homogeneous population of epithelial-like cells and grows optimally at 28 °C. Karyotype analysis revealed that the modal chromosome number of CTE cells was 50. Partial amplification, sequencing and alignment of fragments of two mitochondrial genes 16S rRNA and COI confirmed that CTE cell line originated from catla. Significant green fluorescent signals were observed when the cell line was transfected with phrGFP II-N mammalian expression vector, indicating its potential utility for transgenic and genetic manipulation studies. The CTE cells showed strong positivity for cytokeratin, indicating that cell line was epithelial in nature. The flow cytometric analysis of cell line revealed a higher number of cells in S-phase at 48 h, suggesting a high growth rate. The extracellular products of Vibrio cholerae MTCC 3904 were toxic to the CTE cells. This cell line was not susceptible to fish betanodavirus, the causative agent of viral nervous necrosis in a large variety of marine fish.     

Cell-type specific roles for PTEN in establishing a functional retinal architecture

Background

The retina has a unique three-dimensional architecture, the precise organization of which allows for complete sampling of the visual field. Along the radial or apicobasal axis, retinal neurons and their dendritic and axonal arbors are segregated into layers, while perpendicular to this axis, in the tangential plane, four of the six neuronal types form patterned cellular arrays, or mosaics. Currently, the molecular cues that control retinal cell positioning are not well-understood, especially those that operate in the tangential plane. Here we investigated the role of the PTEN phosphatase in establishing a functional retinal architecture.

Methodology/Principal Findings

In the developing retina, PTEN was localized preferentially to ganglion, amacrine and horizontal cells, whose somata are distributed in mosaic patterns in the tangential plane. Generation of a retina-specific Pten knock-out resulted in retinal ganglion, amacrine and horizontal cell hypertrophy, and expansion of the inner plexiform layer. The spacing of Pten mutant mosaic populations was also aberrant, as were the arborization and fasciculation patterns of their processes, displaying cell type-specific defects in the radial and tangential dimensions. Irregular oscillatory potentials were also observed in Pten mutant electroretinograms, indicative of asynchronous amacrine cell firing. Furthermore, while Pten mutant RGC axons targeted appropriate brain regions, optokinetic spatial acuity was reduced in Pten mutant animals. Finally, while some features of the Pten mutant retina appeared similar to those reported in Dscam-mutant mice, PTEN expression and activity were normal in the absence of Dscam.

Conclusions/Significance

We conclude that Pten regulates somal positioning and neurite arborization patterns of a subset of retinal cells that form mosaics, likely functioning independently of Dscam, at least during the embryonic period. Our findings thus reveal an unexpected level of cellular specificity for the multi-purpose phosphatase, and identify Pten as an integral component of a novel cell positioning pathway in the retina.