Circularly permuted GTPase YqeH binds 30S ribosomal subunit: Implications for its role in ribosome assembly

YqeH, a circularly permuted GTPase, is conserved among bacteria and eukaryotes including humans. It was shown to be essential for the assembly of small ribosomal (30S) subunit in bacteria. However, whether YqeH interacts with 30S ribosome and how it may participate in 30S assembly are not known. Here, using co-sedimentation experiments, we report that YqeH co-associates with 30S ribosome in the GTP-bound form. In order to probe whether YqeH functions as RNA chaperone in 30S assembly, we assayed for strand dissociation and annealing activity. While YqeH does not exhibit these activities, it binds a non-specific single and double-stranded RNA, which unlike the 30S binding is independent of GTP/GDP binding and does not affect intrinsic GTP hydrolysis rates. Further, S5, a ribosomal protein which participates during the initial stages of 30S assembly, was found to promote GTP hydrolysis and RNA binding activities of YqeH.     

Amplification of blue emission of Tm3+ ions in Li2O-HfO2-SiO2 glass system by means of Au0 metallic particles

Li₂O-HfO₂-SiO₂-Tm₂O₃:Au₂O₃ glass samples (containing fixed content of Tm₂O₃ and different concentration of Au₂O₃) were prepared and characterized. Bearing of Au⁰ metallic particles (MPs) on improving blue emission of thulium ions (Tm³⁺) ions was explored. Optical absorption (OA) spectra exhibited multiple bands excited from ³H₆ of Tm³⁺. Additionally, a broad peak in the wavelength range 500–600 nm due to surface plasmon resonance (SPR) of Au⁰ MPs was noticed in the spectra. Photoluminescence (PL) spectra (of thulium free glasses) indicated a peak in the visible range due to sp → d electronic transition of Au⁰ MPs. Luminescence spectra of Tm³⁺ and Au₂O₃ co-doped glasses exhibited intense blue emission with substantial increase of intensity with increase of Au₂O₃ content. Bearing of Au⁰ MPs on the reinforcement of blue emission of Tm³⁺ was discussed in detail with kinetic rate equations.     

Effect of artificial light on activity in frugivorous bats (Pteropodidae)

Journal of Ethology - Artificial lighting at nights (ALAN) affects behaviour in many animals, especially nocturnal species. However, its effect on frugivorous bats remains less explored, especially...     

Comparative role of salps and other zooplankton in the cycling and transport of selected elements and natural radionuclides in Mediterranean waters

Salps, salp fecal pellets and other zooplankton species were analyzed for a suite of elements and natural radionuclides to assess their role in the biogeochemical cycling of nuclides in oceanic waters. The nuclide/Al ratios in organisms normalized to the same ratio in crustal rock indicated that Ca, Sr, Zn, Cu, U,²¹⁰Po, and²¹⁰Pb are enriched in the organisms. The concentrations of Fe, Al, Th isotopes and²¹⁰Pb in salps and fecal pellets were about an order of magnitude higher than those in salps, whereas Ca, Cu, Zn, Mn and Po were higher by factors of about 2–5. Fluxes via salp defecation were higher than those which have been measured in crustacean zooplankton species, a result primarily due to the high defecation rates characteristic of salps. High nuclide levels in salp fecal pellets coupled with high defecation rates and presumed high salp biomass in many areas underscore the importance of these indiscriminate filter feeders in packaging and transporting to depth particulate-associated nuclides in surface waters.