333 research outputs found
Riboflavin induces Metarhizium spp. to produce conidia with elevated tolerance to UV-B, and upregulates photolyases, laccases and polyketide synthases genes
Aims: The effect of nutritional supplementation of two Metarhizium species with riboflavin (Rb) during production of conidia was evaluated on (i) conidial tolerance (based on germination) to UV-B radiation and on (ii) conidial expression following UV-B irradiation, of enzymes known to be active in photoreactivation, viz., photolyase (Phr), laccase (Lac) and polyketide synthase (Pks). Methods and Results: Metarhizium acridum (ARSEF 324) and Metarhizium robertsii (ARSEF 2575) were grown either on (i) potato dextrose agar medium (PDA), (ii) PDA supplemented with 1% yeast extract (PDAY), (iii) PDA supplemented with Rb (PDA+Rb), or (iv) PDAY supplemented with Rb (PDAY+Rb). Resulting conidia were exposed to 866¡7 mW mâ2 of UV-B Quaite-weighted irradiance to total doses of 3¡9 or 6¡24 kJ mâ2. Some conidia also were exposed to 16 klux of white light (WL) after being irradiated, or not, with UV-B to investigate the role of possible photoreactivation. Relative germination of conidia produced on PDA+Rb (regardless Rb concentration) or on PDAY and exposed to UV-B was higher compared to conidia cultivated on PDA without Rb supplement, or to conidia suspended in Rb solution immediately prior to UV-B exposure. The expression of MaLac3 and MaPks2 for M. acridum, as well as MrPhr2, MrLac1, MrLac2 and MrLac3 for M. robertsii was higher when the isolates were cultivated on PDA+Rb and exposed to UV-B followed by exposure to WL, or exposed to WL only. Conclusions: Rb in culture medium increases the UV-B tolerance of M. robertsii and M. acridum conidia, and which may be related to increased expression of Phr, Lac and Pks genes in these conidia. Significance and Impact of the Study: The enhanced UV-B tolerance of Metarhizium spp. conidia produced on Rb-enriched media may improve the effectiveness of these fungi in biological control programs.Fil: Pereira-Junior, R.A.. Universidade Federal de GoiĂĄs; Brasil. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂŠdicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Huarte Bonnet, Carla. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂŠdicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentina. Universidade Federal de GoiĂĄs; BrasilFil: PaixĂŁo, F.R.S.. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂŠdicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; Argentina. Universidade Federal de GoiĂĄs; BrasilFil: Roberts, D.W.. State University of Utah; Estados UnidosFil: Luz, C.. Universidade Federal de GoiĂĄs; BrasilFil: Pedrini, NicolĂĄs. Consejo Nacional de Investigaciones CientĂficas y TĂŠcnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner". Universidad Nacional de la Plata. Facultad de Ciencias MĂŠdicas. Instituto de Investigaciones BioquĂmicas de La Plata "Prof. Dr. Rodolfo R. Brenner"; ArgentinaFil: Fernandes, Ă.K.K.. Universidade Federal de GoiĂĄs; Brasi
Riboflavin induces Metarhizium spp. to produce conidia with elevated tolerance to UV-B, and upregulates photolyases, laccases and polyketide synthases genes
Aims: The effect of nutritional supplementation of two Metarhizium species with riboflavin (Rb) during production of conidia was evaluated on (i) conidial tolerance (based on germination) to UV-B radiation and on (ii) conidial expression following UV-B irradiation, of enzymes known to be active in photoreactivation, viz., photolyase (Phr), laccase (Lac) and polyketide synthase (Pks). Methods and Results: Metarhizium acridum (ARSEF 324) and Metarhizium robertsii (ARSEF 2575) were grown either on (i) potato dextrose agar medium (PDA), (ii) PDA supplemented with 1% yeast extract (PDAY), (iii) PDA supplemented with Rb (PDA+Rb), or (iv) PDAY supplemented with Rb (PDAY+Rb). Resulting conidia were exposed to 866¡7 mW mâ2 of UV-B Quaite-weighted irradiance to total doses of 3¡9 or 6¡24 kJ mâ2. Some conidia also were exposed to 16 klux of white light (WL) after being irradiated, or not, with UV-B to investigate the role of possible photoreactivation. Relative germination of conidia produced on PDA+Rb (regardless Rb concentration) or on PDAY and exposed to UV-B was higher compared to conidia cultivated on PDA without Rb supplement, or to conidia suspended in Rb solution immediately prior to UV-B exposure. The expression of MaLac3 and MaPks2 for M. acridum, as well as MrPhr2, MrLac1, MrLac2 and MrLac3 for M. robertsii was higher when the isolates were cultivated on PDA+Rb and exposed to UV-B followed by exposure to WL, or exposed to WL only. Conclusions: Rb in culture medium increases the UV-B tolerance of M. robertsii and M. acridum conidia, and which may be related to increased expression of Phr, Lac and Pks genes in these conidia. Significance and Impact of the Study: The enhanced UV-B tolerance of Metarhizium spp. conidia produced on Rb-enriched media may improve the effectiveness of these fungi in biological control programs.Instituto de Investigaciones BioquĂmicas de La Plat
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
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