A solar flare type increase in cosmic rays at low latitudes

During the hour following the big solar flare on 23-2-1956, an average increase of +5.7 ± 0.8% has been observed in meson intensity measured with standard telescopes at Ahmedabad, Kodaikanal and Trivandrum. This is the first report of a significant solar flare type increase in cosmic rays near the geomagnetic equator. If the increase is due to solar protons travelling in approximately direct paths, the energy of the protous must extend from about 35-67.5 Bev. It is estimated that the average flux of such protons is approximately equal to 1.5 times the flux of general cosmic ray intensity in the same energy range. During the hour, the sun is estimated to have emitted more than 1028 protons of about 50 Bev energy

Towards the Construction of Expressed Proteomes Using a Leishmania tarentolae Based Cell-Free Expression System

The adaptation of organisms to a parasitic life style is often accompanied by the emergence of novel biochemical pathways absent in free-living organisms. As a result, the genomes of specialized parasitic organisms often code for a large number (>50%) of proteins with no detectable homology or predictable function. Although understanding the biochemical properties of these proteins and their roles in parasite biogenesis is the next challenge of molecular parasitology, analysis tools developed for free-living organisms are often inadequate for this purpose. Here we attempt to solve some of these problems by developing a methodology for the rapid production of expressed proteomes in cell-free systems based on parasitic organisms. To do so we take advantage of Species Independent Translational Sequences (SITS), which can efficiently mediate translation initiation in any organism. Using these sequences we developed a single-tube in vitro translation system based on the parasitic protozoan Leishmania tarentolae. We demonstrate that the system can be primed directly with SITS containing templates constructed by overlap extension PCR. To test the systems we simultaneously amplified 31 of L. tarentolae's putative translation initiation factors and phosphatases directly from the genomic DNA and subjected them to expression, purification and activity analysis. All of the amplified products produced soluble recombinant proteins, and putative phosphatases could be purified to at least 50% purity in one step. We further compared the ability of L. tarentolae and E. coli based cell-free systems to express a set of mammalian, L. tarentolae and Plasmodium falciparum Rab GTPases in functional form. We demonstrate that the L. tarentolae cell-free system consistently produced higher quality proteins than E. coli-based system. The differences were particularly pronounced in the case of open reading frames derived from P. falciparum. The implications of these developments are discussed

Unidirectional constant rate motion of the ribosomal scanning particle during eukaryotic translation initiation

According to the model of translation initiation in eukaryotes, the 40S ribosomal subunit binds to capped 5′-end of mRNA and subsequently migrates along 5′-UTR in searching for initiation codon. However, it remains unclear whether the migration is the result of a random one-dimensional diffusion, or it is an energy-driven unidirectional movement. To address this issue, the method of continuous monitoring of protein synthesis in situ was used for high precision measurements of the times required for translation of mRNA with 5′-UTRs of different lengths and structures in mammalian and plant cell-free systems. For the first time, the relationship between the scanning time and the 5′-UTR length was determined and their linear correlation was experimentally demonstrated. The conclusion is made that the ribosome migration is an unidirectional motion with the rate being virtually independent of a particular mRNA sequence and secondary structure

A mutant which reinitiates the polypeptide chain after chain termination

A mutation, x, in the rII B cistron permits reinitiation of polypeptide synthesis after chain termination. Mutants containing this starter are isolated as base analogue-induced revertants of doubles containing an ochre or amber mutant and a (+) phase-shift mutant. Evidence is provided that such mutants synthesize two polypeptide chains. The starter is initiated in the (−) frame and requires a (+) phase shift on its right to compensate it. Chain termination is obligatory for activation of the starter, but can occur either to its left or its right. Restarting is independent of the phase between the terminator and starter, as shown by altering the phase of termination and by inserting phase-shift mutants between the terminator and starter

Further evidence that UGA does not code for tryptophan

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Short-period fluctuations of cosmic ray intensity at the geomagnetic equator and their solar and terrestrial relationship

By using power spectrum analysis on the μ meson intensity records of a high counting rate instrument (106 counts/min) operated at Chacaltaya, Bolivia, it has been possible to identify the presence of cosmic ray fluctuations of 15 to 19 and 25 to 28 cycles per hour (cph). These frequencies were found at a 99% level of significance in the average of 1034 three-hour samples extending from November 1965 to June 1966. Comparison with Pioneer 6 measurements (Ness et al., 1966) indicates that the magnetosheath field, at a distance of about 10 earth radii (RE), and the interplanetary magnetic field show peaks in spectral density that correspond closely (though not identically) with peaks in muon intensity. It is most plausible that these cosmic ray fluctuations are caused by the fluctuations of geomagnetic field corresponding to an amplitude of about 20 γ in the dipole magnetic field. Magnetic field measurements conducted in the magnetosphere by Explorer 6 (Judge and Coleman, 1962) and Explorer 12 (Patel and Cahill, 1964) show similar oscillations. Recent observations by ATS 1 confirm the presence of magnetic oscillations of similar frequencies at about 6 RE . These frequencies are also found in the geomagnetic micropulsations observed at the surface of the earth. The integrated power of cosmic ray oscillations in the frequency range of 6 to 30 cph has been studied at various periods, and its solar-terrestrial relationship is examined. The association of observed frequencies in cosmic rays with frequencies in the solar photosphere and the interplanetary magnetic field, as well as the resonance frequencies of the magnetosphere, are discussed

Direction of reading the genetic message in reticulocytes

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Short-period variations of cosmic-ray intensity

This article does not have an abstract