27 research outputs found
Assessing the contribution of the herpes simplex virus DNA polymerase to spontaneous mutations
BACKGROUND: The thymidine kinase (tk) mutagenesis assay is often utilized to determine the frequency of herpes simplex virus (HSV) replication-mediated mutations. Using this assay, clinical and laboratory HSV-2 isolates were shown to have a 10- to 80-fold higher frequency of spontaneous mutations compared to HSV-1. METHODS: A panel of HSV-1 and HSV-2, along with polymerase-recombinant viruses expressing type 2 polymerase (Pol) within a type 1 genome, were evaluated using the tk and non-HSV DNA mutagenesis assays to measure HSV replication-dependent errors and determine whether the higher mutation frequency of HSV-2 is a distinct property of type 2 polymerases. RESULTS: Although HSV-2 have mutation frequencies higher than HSV-1 in the tk assay, these errors are assay-specific. In fact, wild type HSV-1 and the antimutator HSV-1 PAA(r)5 exhibited a 2–4 fold higher frequency than HSV-2 in the non-HSV DNA mutatagenesis assay. Furthermore, regardless of assay, HSV-1 recombinants expressing HSV-2 Pol had error rates similar to HSV-1, whereas the high mutator virus, HSV-2 6757, consistently showed signficant errors. Additionally, plasmid DNA containing the HSV-2 tk gene, but not type 1 tk or LacZ DNA, was shown to form an anisomorphic DNA stucture. CONCLUSIONS: This study suggests that the Pol is not solely responsible for the virus-type specific differences in mutation frequency. Accordingly, it is possible that (a) mutations may be modulated by other viral polypeptides cooperating with Pol, and (b) the localized secondary structure of the viral genome may partially account for the apparently enhanced error frequency of HSV-2
All politics is local: the case of the Macrocephalon maleo conservation on Sulawesi, Indonesia
The rich biodiversity of the Indonesian island of Sulawesi is subject to a high rate of deforestation and other pressures. Its plight is symbolized by the deteriorating conservation status of the maleo, an iconic galliform bird that is both striking in appearance and intimately bound up with local traditions. After a series of international-led projects during the 1980s and early 1990s conservation efforts petered out until recently when there has been an upsurge in local-led concern and action. To capitalize on this a workshop was held in 2010 to share local perceptions, lessons and concerns about the species and these conservation efforts. The workshop was dominated by members of local communities and their elected or traditional representatives, although there was also a wide variety of other stakeholders present, including from national species conservation and local government agencies. Whilst there is a need for more information to underpin the actions necessary to ensure the survival of this species, the overwhelming perception of participants was that continued decentralization of policy making and budgetary responsibility would enhance the conservation efforts for this species (and other elements of biodiversity) considerably. This would allow the upsurge in locally-led conservation activities to be continued and expanded.Mochamad Indrawan, Nur Wahid, Marc Argeloo, Suryani Mile-Doucet, John Tasirin, Lian Pin Koh, Marcy Summers, Philip J. K. McGowa
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THE KEPLER-454 SYSTEM: A SMALL, NOT-ROCKY INNER PLANET, A JOVIAN WORLD, and A DISTANT COMPANION
Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687 ± 50 K, its metallicity to be [m/H] = 0.32 ± 0.08, and the projected rotational velocity to be v sin i < 2.4 km s-1. We combine these values with a study of the asteroseismic frequencies from short cadence Kepler data to estimate the stellar mass to be , the radius to be 1.066 ± 0.012 Ro, and the age to be Gyr. We estimate the radius of the 10.6 day planet as 2.37 ± 0.13 R⊕. Using 63 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 36 observations made with the HIRES spectrograph at the Keck Observatory, we measure the mass of this planet to be 6.8 ± 1.4 M⊕. We also detect two additional non-transiting companions, a planet with a minimum mass of 4.46 ± 0.12 MJ in a nearly circular 524 day orbit and a massive companion with a period >10 years and mass >12.1 MJ. The 12 exoplanets with radii <2.7 R⊕ and precise mass measurements appear to fall into two populations, with those <1.6 R⊕ following an Earth-like composition curve and larger planets requiring a significant fraction of volatiles. With a density of 2.76 ± 0.73 g cm-3, Kepler-454b lies near the mass transition between these two populations and requires the presence of volatiles and/or H/He gas