Resistance to quambalaria shoot blight and myrtle rust in Corymbia calophylla seedlings

Corymbia calophylla (marri), an endemic keystone tree species in southwest Western Australia, is increasingly impacted by the introduced basidiomycete smut Quambalaria pitereka. The basidiomycete rust Austropuccinia psidii (myrtle rust), an invasive pathogen recently introduced to Eastern Australia, is expected to spread to the southwest of Western Australia eventually. Austropuccinia psidii has similar epidemiology to Q. pitereka, and there is concern that C. calophylla may be susceptible. Preliminary pathogenicity tests showed significant differences in aggressiveness between twelve Q. pitereka isolates, and there was evidence of interactions between isolates and C. calophylla provenances. Seedlings from 59 open-pollinated families from 11 provenances covering the natural range of marri were screened for resistance to Q. pitereka and A. psidii under controlled glasshouse conditions. Resistance of seedlings within provenances to Q. pitereka and A. psidii differed significantly. There was no significant correlation between resistance to Q. pitereka and resistance to A. psidii. Seedlings of provenances from wetter regions were more resistant to both pathogens, but the correlation coefficients were insignificant. Seedlings of four families in three provenances (Serpentine, Chidlow, and Kingston) showed 100% resistance to Q. pitereka. Narrow-sense heritability estimates were 0.07 for quambalaria shoot blight resistance and 0.34 for myrtle rust resistance. The results indicate the potential to use selected families/individuals resistant to Q. pitereka and A. psidii for tree improvement programs and adaptive management strategies

Protein phosphatase 2A promotes hepatocellular carcinogenesis in the diethylnitrosamine mouse model through inhibition of p53

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Most HCCs develop in cirrhotic livers. Alcoholic liver disease, chronic hepatitis B and chronic hepatitis C are the most common underlying liver diseases. Hepatitis C virus (HCV)-specific mechanisms that contribute to HCC are presently unknown. Transgenic expression of HCV proteins in the mouse liver induces an overexpression of the protein phosphatase 2A catalytic subunit (PP2Ac). We have previously reported that HCV-induced PP2Ac overexpression modulates histone methylation and acetylation and inhibits DNA damage repair. In this study, we analyze tumor formation and gene expression using HCV transgenic mice that overexpress PP2Ac and liver tissues from patients with HCC. We demonstrate that PP2Ac overexpression interferes with p53-induced apoptosis. Injection of the carcinogen, diethylnitrosamine, induced significantly more and larger liver tumors in HCV transgenic mice that overexpress PP2Ac compared with control mice. In human liver biopsies from patients with HCC, PP2Ac expression was significantly higher in HCC tissue compared with non-tumorous liver tissue from the same patients. Our findings demonstrate an important role of PP2Ac overexpression in liver carcinogenesis and provide insights into the molecular pathogenesis of HCV-induced HC

Ground state hyperfine structures of 43K and 44K measured by atomic beam magnetic resonance coupled with laser optical pumping

The ground state hyperfine structures of 43 K and 44K have been measured by an atomic beam magnetic resonance method in which the atoms are spin-polarized by laser optical pumping. The spectroscopic results are : Δv43( 2S1/2) = 192.648 4 (30) MHz and Δν44( 2S1/2) = - 946.718 (3) MHz. The sensitivity of our method is compared to the one achieved in classical ABMR apparatus

Calculations of parity nonconserving s-d transitions in Cs, Fr, Ba II, and Ra II

We have performed ab initio mixed-states and sum-over-states calculations of parity nonconserving (PNC) electric dipole (E1) transition amplitudes between s-d electron states of Cs, Fr, Ba II, and Ra II. For the lower states of these atoms we have also calculated energies, E1 transition amplitudes, and lifetimes. We have shown that PNC E1 transition amplitudes between s-d states can be calculated to high accuracy. Contrary to the Cs 6s-7s transition, in these transitions there are no strong cancelations between different terms in the sum-over-states approach. In fact, there is one dominating term which deviates from the sum by less than 20%. This term corresponds to an s-p_{1/2} weak matrix element, which can be calculated to better than 1%, and a p_{1/2}-d_{3/2} E1 transition amplitude, which can be measured. Also, the s-d amplitudes are about four times larger than the corresponding s-s transitions. We have shown that by using a hybrid mixed-states/sum-over-states approach the accuracy of the calculations of PNC s-d amplitudes could compete with that of Cs 6s-7s if p_{1/2}-d_{3/2} E1 amplitudes are measured to high accuracy.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

Deformation change in light iridium nuclei from laser spectroscopy

Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path 5d^{7}6s ^{2}^{4}F_{9/2} \to 5d^{7}6s6p ^{6}F_{11/2} at 351.5nm were measured for $^{182-189}$Ir, $^{186}Ir^{m}$ and the stable $^{191,193}$Ir. The nuclear magnetic moments μI and the spectroscopic quadrupole moments Qs were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of μI was experimentally determined for the first time for the masses 182≤A≤189 and the isomeric state $^{186}Ir^ m$ . The spectroscopic quadrupole moments of $^{182}$Ir and $^{183}$Ir were measured also for the first time. A large mean square charge radius change between $^{187}$Ir and $^{186}Ir^g$ and between $^{186}Ir^m$ and $^{186}Ir ^g$ was observed corresponding to a sudden increase in deformation: from β2 ≃ + 0.16 for the heavier group A = 193, 191, 189, 187 and 186m to β2 ≥ + 0.2 for the lighter group A = 186g, 185, 184, 183 and 182. These results were analyzed in the framework of a microscopic treatment of an axial rotor plus one or two quasiparticle(s). This sudden deformation change is associated with a change in the proton state that describes the odd-nuclei ground state or that participates in the coupling with the neutron in the odd-odd nuclei. This state is identified with the π3/2+[402] orbital for the heavier group and with the π1/2-[541] orbital stemming from the 1h _9/2 spherical subshell for the lighter group. That last state seems to affect strongly the observed values of the nuclear moments

Detection of optical resonances by observation of fluorescence light emitted from a fast atomic beam when optical pumping occurs

The sensitivity of the method of detection of optical resonances by observation of the fluorescence light emitted from a fast beam excited by a laser in collinear geometry is often limited by the optical pumping. In our method, we propose to take advantage of the optical pumping process to detect optical resonances by using a second laser beam in almost collinear geometry which acts as a detector of optical pumping.La sensibilité de la méthode de détection des résonances optiques par observation de la fluorescence émise par un jet rapide en excitation laser colinéaire est bien souvent limitée par le pompage optique. Nous proposons ici de tirer parti de ce pompage optique pour observer les résonances optiques en les détectant à l'aide d'un second faisceau laser presque colinéaire

Étude de l'effet stark dans les raies de résonance du sodium par une méthode de jet atomique

The atomic beam method previously used at Berkeley for other alkalis, has been applied to the study of the Stark effect in the resonance lines of sodium. The values of the electric polarizabilities of the 3 2P1/2 and 3 2P3/2 levels are deduced : α(3 2P 1/2) = 50,5(5) × 10-24 cm3 ; α (3 2P 3/2, MJ = ∓ 1/2) = 67(8) × 10-24 cm3 ; α (3 2P 3/2, MJ = ∓ 3/2) = 37,5(4) × 10-24 cm3. These results are compared with theoretically determined values.La méthode de jet atomique précédemment utilisée à Berkeley pour d'autres alcalins, est appliquée à l'étude de l'effet Stark dans les raies de résonance du sodium. On en déduit les valeurs des polarisabilités électriques des niveaux 3 2P 1/2 et 3 2P3/2 : α(3 2P 1/2) = 50,5(5) × 10-24 cm3 ; α (3 2P 3/2, MJ = ∓ 1/2) = 67(8) × 10-24 cm3 ; α (3 2P 3/2, MJ = ∓ 3/2) = 37,5(4) × 10-24 cm3. Ces résultats sont comparés à des déterminations théoriques

Utilisation d'un interféromètre de Michelson pour l'étalonnage des spectres obtenus à l'aide du spectromètre Fabry-Perot photo-électrique

To calibrate the spectrum given by the "Hypeac" (Fabry-Perot photoelectric spectrometer), we have used an auxiliary Michelson interferometer of the Saunders type. By comparison with measurements made by R. H. Kohler using radio-frequencies techniques on the mercury line λ = 4 077 Å, we show that a precision of 10-4 is easily attained.L'étalonnage des spectres obtenus à l'aide du spectromètre photo-électrique Fabry-Perot (« Hypeac ») est réalisé à l'aide d'un interféromètre de Michelson du type Saunders. Par comparaison avec des mesures effectuées avec des techniques de radio-fréquence, sur la raie λ = 4 077 Å, on montre qu'une précision de 10-4 peut être atteinte facilement à l'aide de ce dispositif

Observation of optical pumping effects in collinear atomic beam - laser beam(s) interaction

The detection of optical resonances by observation of the fluorescence light emitted from a fast atomic beam of Na interacting with a collinear laser beam is limited in sensitivity by optical pumping processes. In the experiment reported here, we take advantage of the optical pumping by using a second collinear laser beam, achieving then a gain in fluorescence signal. The effects of the lasers power and polarization on line shapes have been studied in the single laser excitation case as well as in the two laser beams one.La sensibilite de la méthode de détection des résonances optiques par observation de la fluorescence émise par un jet rapide en excitation colineaire, est limitée par le pompage optique. Dans l' expérience décrite ici, nous tirons parti de ce pompage optique en détectant les résonances optiques à l'aide d'un second laser colinéaire, réalisant ainsi un gain sensible en signal de fluorescence. Les effets de la polarisation et de la puissance des faisceaux laser ont été étudiés aussi bien dans le cas de l'excitation d'atomes de Na par un seul laser que par deux lasers

qPCR assays for sensitive and rapid detection of Quambalaria species from plant tissues

Several species from the genus Quambalaria (order Microstromatales) cause diseases on eucalypts (Eucalyptus and related genera) both in plantations and natural ecosystems. We developed real-time quantitative PCR (qPCR) assays to rapidly detect and distinguish five Quambalaria species. The design of the species-specific qPCR assay for each species, Q. pitereka (PIT), Q. coyrecup (COR), Q. cyanescens (CYN), Q. pusilla (PUS), and Q. eucalypti (EUC), was based on the ITS region and was evaluated for specificity and sensitivity. The PIT, COR, and CYN qPCR assays could amplify as little as 10 fg µl−1 from pure cultures, whereas PUS and EUC qPCR assays could amplify 100 fg µl−1 of their target species. The PIT, COR, and CYN qPCR assays were further validated using naturally and artificially infected samples of their plant host Corymbia calophylla. These assays will be used for rapid diagnostics and future experiments on the infection process