Gene expression strategies of barley yellow dwarf virus

Barley yellow dwarf virus (BYDV) has a positive sense, 5.7kb RNA genome encoding at least six open reading frames (ORFs). BYDV uses variety of unusual translational strategies to express its genes. These include frameshifting in the polymerase (60K) ORF, leaky scanning at the AUGs of the overlapping coat protein (CP) and 17K ORFs, and readthrough of the CP stop codon;Full-length cDNA clone of BYDV-PAV has been constructed to understand functions of different viral genes and the roles of specific sequences in translation, replication and encapsidation. Translation in cell-free extracts using in vitro synthesized full-length transcripts resulted in expected 99 kDa frameshift product. These transcripts were biologically active. The 39K ORF at the 5\u27 end of the genome overlaps by 13 nucleotides with a 60K ORF. The region of overlap contains a shifty heptanucleotide, followed by a highly structured region that may contain a pseudoknot. The 39K ORF stop codon immediately next to the shifty heptanucleotide sequence is necessary for in vivo frameshifting and viral replication. Deletion mutants indicate that the ORF1, ORF2 and ORF6 or 3[superscript]\u27 terminal 1157 nucleotides are necessary for BYDV-PAV replication in protoplasts;The CP, 17K and 50K ORFs located at the 3\u27 half of the genome are expressed from a tricistronic subgenomic RNA (sgRNA1), that is generated in infected cells. The 17K ORF is embedded in the sequence that encodes the CP ORF, in a different reading frame. The 17K ORF start codon is 43 bases downstream of the CP start codon. Ribosomes initiate translation at the start codons of both ORFs, giving rise to both proteins. Systematic mutagenesis was performed to show, in vitro and in vivo, that overlapping ORFs of the sgRNA1 are expressed by Kozak\u27s leaky scanning mechanisms. A new ribosome pausing model is proposed to explain the unexpected observation that mutations that reduce translation initiation at the downstream 17K AUG also reduce initiation at the upstream CP AUG. Implications of these results on expression of luteovirus coat protein in transgenic plants are discussed;The 50K ORF is translated by readthrough of the CP stop codon, giving rise to 72 kDa polypeptide in vitro. The GUS reporter gene was inserted downstream of the CP stop codon in the full-length BYDV-PAV infectious clone to elucidate the mechanism of readthrough for the luteovirus class. Results indicate that the signals required in luteovirus class are more complex and different from the well-studied tobacco mosaic virus like group of readthrough. Use of readthrough strategy to express biologically active recombinant proteins are discussed

Wells and ill-fare: impacts of well failures on cultivators in hard rock areas of Madhya Pradesh

WellsDrillingCostsGroundwater depletionWater tableGroundwater irrigationOwnershipEconomic impactSocial impactCrop managementFood security

Intensity interferometry of thermal photons from relativistic heavy ion collisions

Intensity interferometry of thermal photons, having transverse momenta $k_T \approx$ 0.1 -- 2.0 GeV, produced in relativistic collision of heavy nuclei is studied. It is seen to provide an accurate information about the temporal and spatial structure of the interacting system. The source dimensions and their $k_T$ dependence revealed by the photon interferometry, display a richness not seen in pion interferometry. We attribute this to difference in the source functions, the fact that photons come out from every stage of the collision and from every point in the system, and the fact that the rate of production of photons is different for the quark-gluon plasma, which dominates the early hot stage, and the hadronic matter which populates the last phase of the collision dynamics. The usefulness of this procedure is demonstrated by an application to collision of lead nuclei at the CERN SPS. Prediction for the transverse momentum dependence of the sizes for SPS, RHIC, and LHC energies are given.Comment: 16 pages, 11 figures. Added discussions and references. To appear in Phys. Rev.

Response of the Arabian Sea to global warming and associated regional climate shift

The response of the Arabian Sea to global warming is the disruption in the natural decadal cycle in the sea surface temperature (SST) after 1995, followed by a secular warming. The Arabian Sea is experiencing a regional climate-shift after 1995, which is accompanied by a five fold increase in the occurrence of “most intense cyclones”. Signatures of this climate-shift are also perceptible over the adjacent landmass of India as: (1) progressively warmer winters, and (2) decreased decadal monsoon rainfall. The warmer winters are associated with a 16-fold decrease in the decadal wheat production after 1995, while the decreased decadal rainfall was accompanied by a decline of vegetation cover and increased occurrence of heat spells. We propose that in addition to the oceanic thermal inertia, the upwelling-driven cooling provided a mechanism that offset the CO2-driven SST increase in the Arabian Sea until 1995

What drives the increased phytoplankton biomass in the Arabian Sea?

The seasonal variability of phytoplankton biomass in the Arabian Sea, though a well researched topic, its inter-annual variability is less explored and understood. Analysis of the satellite-derived chlorophyll pigment concentration in the Arabian Sea during 1997–2007 showed a weak increasing trend. Contrary to the earlier hypothesis, our analysis showed that this increased phytoplankton biomass was not driven by the strengthening winds during summer monsoon. In fact, the basin-averaged chlorophyll concentrations during summer monsoon tend to decline, whereas those in September–October and during the winter monsoon showed an increasing trend. Based on the analysis of wind and aerosol optical thickness data, we attribute the increased phytoplankton biomass during September–October to dust-induced iron fertilization when there is sufficient buildup of nitrate in the upper ocean. During winter, the enhanced evaporative cooling under the strengthening winds led to the increased convective mixing. Subsequent supply of subsurface nutrients to the euphotic zone coupled with the increased dust delivery support the observed increase in phytoplankton biomass during winter

COLLAGEN FROM SQUID AND ITS BIOLOGICAL ACTIVITY

Collagen is the sole protein found predominantly in the animal kingdom. The main source of collagen which had been land animals previously is being replaced by other alternative sources due to certain health related, religious and social concerns. Thus additional reliable, safer and productive options for collagen extraction have been studied extensively since then. Its wide-ranging application, especially in the biomedical and cosmetic field, is also a basis for its study to have become a topic of interest among the researchers. Isolation of collagen from the processing wastes of marine organisms has been receiving a lot of attention recently due to the promising outcome it brings forth. In the current review, we have focused upon squid, mainly its processing waste, as an alternative source of collagen including the studies carried out on the same to a certain extent

A note on the eight bar grouper, Hyporthodus octofasciatus (Griffin, 1926) (Pisces: Serranidae) from Indian waters

A single specimen of a serranid fish Hyporthodus octofasciatus of length 213 mm TL was collected during a commercial trawl operation off the South western coast of India, during March 2011 from a depth of 200 m. The present paper provides description, morphometric and meristic features of specimen and comparative account with earlier descriptions

आनडमान द्वीपों की रीफ मछलियाँ – एक लघु सर्वेक्षण

कृपया पूरा लेखा पढ

Stabilisation of diaphyseal fractures of both bones forearm with limited contact dynamic compression or locked compression plate: comparison of clinical outcomes

Background: The inception of Locking Compression Plate (LCP) has revolutionized fracture management. With their dramatic success for articular fractures, there is a speculation that they might be more appropriate for diaphyseal fractures as well.Methods: In this randomized prospective cohort study, 56 patients with diaphyseal fractures involving both bones of forearm were segregated into two groups based on internal fixation with Limited contact dynamic compression plate (LC-DCP)(n=28) or with Locking compression plate (LCP)(n=26). Clinical and radiological parameters were studied and functional evaluation was done with Disabilities of arm, shoulder, and hand (DASH) score.Results: Andersons’ criteria was employed to categorize the functional results. The mean duration of surgery and time to union were discovered to be less in favor of LCP group although statistically insignificant. No significant differences in two groups with respect to the functional evaluation (range of movement, Andersons’ criteria and DASH score) and complications could be discerned. No incidence of refracture or synostosis was encountered in any of the group. Conclusions: Although LCP is an effective treatment alternative and may have a subtle edge over LC-DCP in the management of these fractures, their supremacy could not be certified. We deduce that surgical planning and expertise rather than the choice of implant are more pivotal for outstanding results