217 research outputs found
A cRNA Probe Detects Prunus Necrotic Ringspot Virus in Three Peach Cultivars after Micrografting and in Peach Shoots following Long-term Culture at 4°C
As part of a program to develop transgenic peach (Prunus persica L. Batsch) cultivars with resistance to Prunus necrotic ringspot virus (PNRSV), we are testing a system for measuring virus in peach shoot cultures. Micrografting in vitro is used for inoculation and slot-blot hybridization, with a digoxigenin (DIG)-labeled cRNA probe complementary to the 5ÂŽ open reading frame (ORF) of PNRSV RNA 3, for detection. In this study, we investigated whether infected shoots maintain virus infection over long periods of culture at 4°C and if PNRSV-infected âSuncrestâ shoot cultures can serve as graft bases to transmit virus equally well into cultivars Nemaguard, Springcrest, and Suncrest. The results of RNA hybridization analysis showed that virus was present in extracts of leaf samples from 2-year-old PNRSV-infected âSuncrestâ shoots that had been subjected to varying lengths of incubation at 4 °C in the dark, suggesting that infected shoots can be maintained for repeated use. Rates of graft success were higher in heterografts between âSuncrestâ bases and tips of âSpringcrestâ or âNemaguardâ than in autografts between âSuncrestâ and âSuncrestâ, and there was equal efficacy of graft inoculation from âSuncrestâ into these three cultivars
The combined use of selective deuteration and double resonance experiments in assigning the 1H resonances of valine and tyrosine residues of dihydrofolate reductase
AbstractSelective deuteration is a general solution to the resolution problem which limits the application of double resonance experiments to the assignment of the 1H NMR spectra of proteins. Spin-decoupling and NOE experiments have been carried out on Lactobacillus casei dihydrofolate reductase and on selectively deuterated derivatives of the enzyme containing either [Îł-2H6]Val or (α,ÎŽ2,Ï”1-2H3]His, [α,ÎŽ1,ÎŽ2,Ï”1,Ï”2,ζ-2H6]Phe, [α,ÎŽ1,Ï”3,ζ2,ζ3,η2-2H6]Trp and [α,Ï”1,Ï”2-2H3]Tyr. When combined with ring-current shift calculations based on the crystal structure of the enzyme, these experiments allow us to assign 1H resonances of Val 61, Val 115, Tyr 46 and Tyr 68
An Efficient Ligation Method in the Making of an in vitro Virus for in vitro Protein Evolution
The âin vitro virusâ is a molecular construct to perform evolutionary protein engineering. The âvirion (=viral particle)â (mRNA-peptide fusion), is made by bonding a nascent protein with its coding mRNA via puromycin in a test tube for in vitro translation. In this work, the puromycin-linker was attached to mRNA using the Y-ligation, which was a method of two single-strands ligation at the end of a double-stranded stem to make a stem-loop structure. This reaction gave a yield of about 95%. We compared the Y-ligation with two other ligation reactions and showed that the Y-ligation gave the best productivity. An efficient amplification of the in vitro virus with this âviral genomeâ was demonstrated
Developing a predictive modelling capacity for a climate change-vulnerable blanket bog habitat: Assessing 1961-1990 baseline relationships
Aim: Understanding the spatial distribution of high priority habitats and
developing predictive models using climate and environmental variables to
replicate these distributions are desirable conservation goals. The aim of this
study was to model and elucidate the contributions of climate and topography to
the distribution of a priority blanket bog habitat in Ireland, and to examine how
this might inform the development of a climate change predictive capacity for
peat-lands in Ireland.
Methods: Ten climatic and two topographic variables were recorded for grid
cells with a spatial resolution of 1010 km, covering 87% of the mainland
land surface of Ireland. Presence-absence data were matched to these variables
and generalised linear models (GLMs) fitted to identify the main climatic and
terrain predictor variables for occurrence of the habitat. Candidate predictor
variables were screened for collinearity, and the accuracy of the final fitted GLM
was evaluated using fourfold cross-validation based on the area under the curve
(AUC) derived from a receiver operating characteristic (ROC) plot. The GLM
predicted habitat occurrence probability maps were mapped against the actual
distributions using GIS techniques.
Results: Despite the apparent parsimony of the initial GLM using only climatic
variables, further testing indicated collinearity among temperature and precipitation
variables for example. Subsequent elimination of the collinear variables and
inclusion of elevation data produced an excellent performance based on the AUC
scores of the final GLM. Mean annual temperature and total mean annual
precipitation in combination with elevation range were the most powerful
explanatory variable group among those explored for the presence of blanket
bog habitat.
Main conclusions: The results confirm that this habitat distribution in general
can be modelled well using the non-collinear climatic and terrain variables tested
at the grid resolution used. Mapping the GLM-predicted distribution to the
observed distribution produced useful results in replicating the projected
occurrence of the habitat distribution over an extensive area. The methods
developed will usefully inform future climate change predictive modelling for
Irelan
Systems genetics identifies a role for Cacna2d1 regulation in elevated intraocular pressure and glaucoma susceptibility
Glaucoma is a multi-factorial blinding disease in which genetic factors play an important role. Elevated intraocular pressure is a highly heritable risk factor for primary open angle glaucoma and currently the only target for glaucoma therapy. Our study helps to better understand underlying genetic and molecular mechanisms that regulate intraocular pressure, and identifies a new candidate gene, Cacna2d1, that modulates intraocular pressure and a promising therapeutic, pregabalin, which binds to CACNA2D1 protein and lowers intraocular pressure significantly. Because our study utilizes a genetically diverse population of mice with kno
Physiological and biochemical adaptations to training in Rana pipiens
Fifteen Rana pipiens were trained on a treadmill thrice weekly for 6.5 weeks to assess the effects of training on an animal that supports activity primarily through anaerobiosis. Endurance for activity increased 35% in these frogs as a result of training ( P =0.006, Fig. 1). This increased performance was not due to enhanced anaerobiosis. Total lactate produced during exercise did not differ significantly for the trained or untrained animals in either gastrocnemius muscle (2.77±0.21 and 2.82±0.13 mg/g, respectively) or whole body (1.32±0.10 and 1.47±0.06 mg/g, respectively). Glycogen depletion also did not differ between the two groups (Fig. 2c). The primary response to training appeared to involve augmentation of aerobic metabolism, a response similar to that reported for mammals. Gastrocnemius muscles of trained frogs underwent a 38% increase over those of untrained individuals in the maximum activity of citrate synthase (14.5±1.0 and 10.5±0.9 Όmoles/(g wet wt·min); P =0.008). This enzyme was also positively correlated with the level of maximum performance for all animals tested ( r =0.61, P <0.01) and with the degree of improvement in the trained animals ( r =0.72, P <0.05). In addition to an increased aerobic capacity, the trained animals demonstrated a greater removal of lactate from the muscle 15 min after fatigue (Fig. 2b).Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47124/1/360_2004_Article_BF00710002.pd
A cyclic universe with colour fields
The topology of the universe is discussed in relation to the singularity
problem. We explore the possibility that the initial state of the universe
might have had a structure with 3-Klein bottle topology, which would lead to a
model of a nonsingular oscillating (cyclic) universe with a well-defined
boundary condition. The same topology is assumed to be intrinsic to the nature
of the hypothetical primitive constituents of matter (usually called preons)
giving rise to the observed variety of elementary particles. Some
phenomenological implications of this approach are also discussed.Comment: 21 pages, 9 figures; v.4: final versio
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