Papaya Ringspot Virus Resistance of Transgenic Rainbow and SunUp is Affected by Gene Dosage, Plant Development, and Coat Protein Homology

R1 plants of the transgenic papaya line 55-1, which expresses a single coat protein (CP) gene of the mild strain of the papaya ringspot virus (PRSV) HA from Hawaii, were previously shown to be resistant only to PRSV isolates from Hawaii. Two transgenic papaya cultivars were subsequently derived from line 55-1. UH SunUp (SunUp) is homozygous for the CP gene insertion and UH Rainbow (Rainbow) is hemizygous for the CP gene because it is a F1 hybrid of a cross between SunUp and the nontransgenic papaya cultivar Kapoho. To determine the various parameters that affect the resistance of SunUp and Rainbow, plants at different developmental stages (younger and older) were inoculated with PRSV isolates from Hawaii, Brazil, Jamaica, and Thailand. Hawaiian isolates shared nucleotide sequence identities of 96.7-99.8% to the CP transgene, and the other isolates shared sequence identities of 89.5-92.5%. Resistance was affected by CP gene dosage, plant developmental stage, and CP sequence identity of the challenge isolate. Young and older hemizygous Rainbow plants were resistant to the homologous PRSV HA (99.8% homology to CP transgene), while only older Rainbow plants were resistant to the other Hawaiian isolates (96.7% homology). However, all inoculated Rainbow plants were susceptible to PRSV isolates collected from Jamaica, Brazil, and Thailand. In contrast, SunUp was resistant to all PRSV isolates, except the one from Thailand, regardless of the plant developmental stage. Resistance to the Thailand isolate, which shares 89.5% homology to the transgene, was observed only with SunUp plants inoculated at an older stage. Steady state RNA analysis and nuclear run-on experiments suggested that resistance of the transgenic papaya is RNA-mediated via post-transcriptional gene silencin

Lower limit on the neutralino mass in the general MSSM

We discuss constraints on SUSY models with non-unified gaugino masses and R_P conservation. We derive a lower bound on the neutralino mass combining the direct limits from LEP, the indirect limits from gmuon, bsgamma, Bsmumu and the relic density constraint from WMAP. The lightest neutralino (mneutralino=6GeV) is found in models with a light pseudoscalar with MA<200GeV and a large value for $tan\beta$. Models with heavy pseudoscalars lead to mneutralino>18(29)GeV for $\tan\beta=50(10)$. We show that even a very conservative bound from the muon anomalous magnetic moment can increase the lower bound on the neutralino mass in models with mu<0 and/or large values of $\tan\beta$. We then examine the potential of the Tevatron and the direct detection experiments to probe the SUSY models with the lightest neutralinos allowed in the context of light pseudoscalars with high $\tan\beta$. We also examine the potential of an e+e- collider of 500GeV to produce SUSY particles in all models with neutralinos lighter than the W. In contrast to the mSUGRA models, observation of at least one sparticle is not always guaranteed.Comment: 37 pages, LateX, 16 figures, paper with higher resolution figures available at http://wwwlapp.in2p3.fr/~boudjema/papers/bound-lsp/bound-lsp.htm

Human macrophages differentiated in the presence of vitamin D3 restrict dengue virus infection and innate responses by downregulating mannose receptor expression

ABSTARCT: Severe dengue disease is associated with high viral loads and overproduction of pro-inflammatory cytokines, suggesting impairment in the control of dengue virus (DENV) and the mechanisms that regulate cytokine production. Vitamin D3 has been described as an important modulator of immune responses to several pathogens. Interestingly, increasing evidence has associated vitamin D with decreased DENV infection and early disease recovery, yet the molecular mechanisms whereby vitamin D reduces DENV infection are not well understood. METHODS AND PRINCIPAL FINDINGS: Macrophages represent important cell targets for DENV replication and consequently, they are key drivers of dengue disease. In this study we evaluated the effect of vitamin D3 on the differentiation of monocyte-derived macrophages (MDM) and their susceptibility and cytokine response to DENV. Our data demonstrate that MDM differentiated in the presence of vitamin D3 (D3-MDM) restrict DENV infection and moderate the classical inflammatory cytokine response. Mechanistically, vitamin D3-driven differentiation led to reduced surface expression of C-type lectins including the mannose receptor (MR, CD206) that is known to act as primary receptor for DENV attachment on macrophages and to trigger of immune signaling. Consequently, DENV bound less efficiently to vitamin D3-differentiated macrophages, leading to lower infection. Interestingly, IL-4 enhanced infection was reduced in D3-MDM by restriction of MR expression. Moreover, we detected moderate secretion of TNF-α, IL-1β, and IL-10 in D3-MDM, likely due to less MR engagement during DENV infection. CONCLUSIONS/SIGNIFICANCE: Our findings reveal a molecular mechanism by which vitamin D counteracts DENV infection and progression of severe disease, and indicates its potential relevance as a preventive or therapeutic candidate

Factors affecting body temperatures of toads

Factors influencing levels and rates of variation of body temperature ( T b ) in montane Bufo boreas boreas and in lowland Bufo boreas halophilus were investigated as an initial step toward understanding the role of natural thermal variation in the physiology and energetics of these ectothermic animals. Body temperatures of boreas can vary 25–30° C over 24-h periods. Such variation is primarily due to both nocturnal and diurnal activity and the physical characteristics of the montane environment. Bufo boreas halophilus are primarily nocturnal except during breeding and are voluntarily active at body temperatures ranging between 10 and 25° C. Despite variation in T b encountered in the field, boreas select a narrow range of T b in a thermal gradient, averaging 23.5 and 26.2° C for fasted individuals maintained under field conditions or acclimated to 20° C, respectively. In a thermal gradient the mean T b of fasted halophilus acclimated to 20° C is 23.9° C. Skin color of boreas varies in the field from very dark to light. The dark skins absorb approximately 4% more radiation than the light ones. Light colored boreas should absorb approximately 5% more radiation than similarly colored halophilus . Evaporative water losses increase directly with skin temperatures and vapor pressure deficit in both subspecies. Larger individuals heat and cool more slowly than smaller ones. Calculation of an enery budget for boreal toads suggests that they could sit in direct sunlight for long periods without fatally overheating, providing the skin was continually moist.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47722/1/442_2004_Article_BF00344732.pd

REGENERATION OF TRANSGENIC PAPAYA (Carica papaya) PLANTS

Stable transformation of papaya (Carica papaya L.) has been achieved following DNA delivery via high velocity microprojectiles. Three types of embryogenic tissues, including immature zygotic embryos, hypocotyl sections, and somatic embryos derived from both, were bombarded with tungsten particles carrying chimeric genes coding for NPT II, GUS, and the coat protein of a mild mutant strain HA 5-1 of papaya ringspot virus. All tissue types were cultured prior to and following particle bombardment on half-strength.MS medium supplemented with 10 mg/1-1 2,4-D, 400 mg/lrI glutamine, and 6% sucrose. Upon transfer to 2,4-D-free medium containing 150 mg/l-1 kanamycin sulfate, 12 isolates regenerated somatic embryos, and five of these produced leafy shoots six to nine months following bombardment. Tissues from 11 isolates were assayed for NPTII activity, and nine were positive. Five out of 12 isolates assayed for GUS expression were positive. Three isolates were positive for both NPTII and GUS

Crystalline and Molecular Structures of Anhydrous Lanthanide PerchloratesLn(ClO4)3withLn=La, Ce, Pr, Sm, Eu, Ho, Er, Tm, and Lu

International audienceThe anhydrous perchloratesLn(ClO4)3, where ClO4is coordinated toLnatoms (Ln=La, Ce, Pr, Sm, Eu, Ho, Er, Tm, and Lu) crystallize in two distinct groups of isostructural species. Rietveld refinements show that from lanthanum to thulium (low temperature form), the crystal system is hexagonal (space groupP63/m,Z=2) with 9.400(3) Å<a<9.201(1) Å and 5.918(1) Å<c<5.563(1) Å. The Rietveld refinement converged toRF=0.033,Rp=0.029, andRwp=0.053 for Eu(ClO4)3. The channeled structure is built on the basis of slightly distorted tricaped trigonal Eu centered prisms of nine oxygen atoms belonging to nine tridentate [ClO4]. Thullium (high temperature form) and lutetium crystallize in trigonalR3cunit cells (Z=6) with, respectively,a=8.13286(2) Å,c=24.1586(1) Å, anda=8.11559(4) Å,c=24.0047(1) Å. For Lu(ClO4)3,RF,Rp, andRwpwere 0.039, 0.046, and 0.061, respectively. Its molecular structure consists of infinite layers of Lu atoms in a tricaped trigonal antiprism surrounding of oxygens. Layers and linkages between layers are ensured by simultaneously bridging and chelating tridentate [ClO4]

Line 63-1: A New Virus-resistant Transgenic Papaya

The disease resistance of a transgenic line expressing the coat protein (CP) gene of the mild strain of the papaya ringspot virus (PRSV) from Hawaii was further analyzed against PRSV isolates from Hawaii and other geographical regions. Line 63-1 originated from the same transformation experiment that resulted in line 55-1 from which the transgenic commercial cultivars, `Rainbow' and `SunUp', were derived. Plants of line 63-1 used in this study consisted of a population from a self pollinated R0 bisexual plant. ELISA and PCR tests provided evidence that there are at least two segregating CP loci. To allow for comparison with reactions of the previously reported line 55-1, virus isolates from Hawaii, Brazil, Thailand, and Jamaica were used to challenge seedlings of 63-1. Unlike line 55-1, a significant percentage of inoculated transgenic plants were susceptible to isolates from Hawaii. However, a proportion of plants were resistant to the non-Hawaiian isolates. In contrast, previous work showed that all plants of the hemizygous line 55-1 were susceptible to PRSV isolates from Brazil, Thailand, and Jamaica. Line 63-1, therefore, presents Hawaii with PRSV-resistant transgenic germplasm that could be used as a source of transgenes for resistance to PRSV isolates within and outside of Hawai