First Record of Bacterial Crown Rot of Papaya (Carica papaya) Caused by an Erwinia papayae-Like Bacterium in the Kingdom of Tonga

Symptoms resembling papaya bacterial crown rot (1,3) attributed to Erwinia papayae were first observed on 'Waimanalo' and 'Solo Sunrise' papaya on the island of Tongatapu, Kingdom of Tonga in July 2009. Spreading, dark green, water-soaked lesions formed on juvenile stem tissue and developed into a foul-smelling, wet rot that destroyed large sections of the stem. Coalescing, brown, angular, marginal, and intercostal lesions killed large areas of the lamina. Elongated lesions on petioles resulted in breakage and leaf death. Symptoms on stems typically moved toward the crown with the growing point being killed or the whole crown breaking off at a canker below. Isolations at 28°C on King's medium B (KB) yielded slow-growing, raised, white, mucoid colonies that produced a conspicuous, nondiffusable blue pigment in the medium. Two-day-old suspensions (1 × 10⁸ CFU/ml) of two cultures were injected into juvenile stem tissue, petioles, and laminae of four healthy papaya seedlings of 'Solo Sunrise' with a sterile 1-ml insulin syringe. Sterile water was used as a negative control. Typical water-soaked lesions appeared at all bacterial inoculation sites on all plants within 5 days but not on controls. Pigment-producing colonies similar to those used for inoculation were reisolated from four different stem lesions. Bacteria isolated from diseased tissues were gram negative, facultative anaerobes, oxidase negative, nonfluorescent on KB, induced a hypersensitive reaction on tobacco leaves, but could not cause soft rot on potato slices. Those characteristics, combined with blue pigment production, are consistent with the bacterium E. papayae. A partial sequence of the 16S rDNA gene of ~804 bp was amplified from four Tongan isolates (ICMP18248-18251) using primers 27f and 1492r (4). Sequences of these strains were 100% identical to each other (GenBank Nos. HQ286366-HQ286369), 99 and 98% identical to the 16SrDNA sequences of E. mallotivora strains LMG2708 (Z96084.1) and DSM4565 (AJ233414.1) respectively, and 97% identical to the 16SrDNA sequence of E. papayae strain NCPPB 4294 (AY131237.1). E. mallotivora and E. papayae cause different diseases, a leaf spot on Mallotus japonicus (2) and bacterial canker on papaya, respectively. They are closely related and in the laboratory are distinguished by only very few biochemical characteristics (1). E. papayae produces a blue pigment on KB and can utilize arabinose but not mannitol. E. mallotivora does not produce a blue pigment and can utilize mannitol but not arabinose. The four Tongan strains produced a blue pigment and could utilize mannitol and arabinose. Symptoms caused by the strains isolated from Tonga are typical of those caused by E. papayae and the strains identified share most of the characteristics of E. papayae. Because the Tongan strains were able to utilize mannitol as well as arabinose and their 16S rDNA was only 97% similar to E. papayae, these strains are referred to as an E. papayae-like bacterium. The taxonomic position of these isolates will be resolved with techniques such as Multilocus Sequence Typing analysis. To our knowledge, this is the first report of this highly destructive papaya disease in the Kingdom of Tonga and of a pathogen closely related to E. papaya in the country. References: (1) L. Gardan et al. Int. J. Syst. Bacteriol. 54:107, 2004. (2) M. Goto. Int. J. Syst. Bacteriol. 26:467, 1976. (3) N. H. Maktar et al. New Dis. Rep. 17:4, 2008. (4) F. Martin-Laurent et al. Appl. Environ. Microbiol. 67:2354, 2001.

Search for ZH → l+ l- bb production in 4.2 fb(-1) of pp collisions at sqrt[s] =1 .96 TeV

We present a search for the standard model Higgs boson produced in association with a Z boson in 4.2 fb(-1) of pp collisions, collected with the D0 detector at the Fermilab Tevatron at sqrt[s] =1 .96 TeV. Selected events contain one reconstructed Z → e+ e- or Z → μ+ μ- candidate and at least two jets, including at least one b-tagged jet. In the absence of an excess over the background expected from other standard model processes, limits on the ZH cross section multiplied by the branching ratios are set. The limit at M(H) = 115  GeV is a factor of 5.9 larger than the standard model prediction.

Epigenetic inactivation of T-box transcription factor 5, a novel tumor suppressor gene, is associated with colon cancer

T-box transcription factor 5 (TBX5) is a member of a phylogenetically conserved family of genes involved in the regulation of developmental processes. The function of TBX5 in cancer development is largely unclear. We identified that TBX5 was preferentially methylated in cancer using methylation-sensitive arbitrarily primed PCR. We aim to clarify the epigenetic inactivation, biological function and clinical significance of TBX5 in colon cancer. Promoter methylation was evaluated by combined bisulfite restriction analysis and bisulfite genomic sequencing. Cell proliferation was examined by cell viability assay and colony formation assay, apoptosis by flow cytometry and cell migration by wound-healing assay. TBX5 target genes were identified by cDNA microarray analysis. Cox regression model and log-rank test were used to identify independent predictors of prognosis. TBX5 was silenced or downregulated in 88% (7/8) colon cancer cell lines, but was expressed in normal colon tissues. Loss of gene expression was associated with promoter methylation. The biological function of TBX5 in human colon cancer cells was examined. Re-expression of TBX5 in silenced colon cancer cell lines suppressed colony formation (P<0.001), proliferation (P<0.001), migration and induced apoptosis (P<0.01). Induction of apoptosis was mediated through cross-talk of extrinsic apoptosis pathway, apoptotic BCL2-associated X protein and Granzyme A signaling cascades. TBX5 suppressed tumor cell proliferation and metastasis through the upregulation of cyclin-dependent kinase inhibitor 2A, metastasis suppressor 1 and downregulation of synuclein gamma and metastasis-associated protein 1 family member 2. TBX5 methylation was detected in 68% (71/105) of primary colon tumors. Multivariate analysis showed that patients with TBX5 methylation had a significantly poor overall survival (P=0.0007). In conclusion, we identified a novel functional tumor suppressor gene TBX5 inactivated by promoter methylation in colon cancer. Detection of methylated TBX5 may serve as a potential biomarker for the prognosis of this malignancy.

The electronic structure of epitaxially stabilized 5d perovskite Ca(1-x)Sr(x)IrO3 (x = 0, 0.5, and 1) thin films: the role of strong spin-orbit coupling

We have investigated the electronic structure of meta-stable perovskite Ca(1 - x)Sr(x)IrO(3)(x = 0, 0.5, and 1) thin films using transport measurements, optical spectroscopy, and first-principles calculations. We artificially fabricated the perovskite phase of Ca(1 - x)Sr(x)IrO(3), which has a hexagonal or post-perovskite crystal structure in bulk form, by growing epitaxial thin films on perovskite GdScO(3) substrates using an epi-stabilization technique. The transport properties of the perovskite Ca(1 - x)Sr(x)IrO(3) films systematically change from nearly insulating (or semi-metallic) for x = 0 to weakly metallic for x = 1. Due to the extended wavefunctions, 5d electrons are usually delocalized. However, the strong spin-orbit coupling in Ca(1 - x)Sr(x)IrO(3) results in the formation of effective total angular momentum J(eff) = 1/2 and 3/2 states, which puts Ca(1 - x)Sr(x)IrO(3) in the vicinity of a metal-insulator phase boundary. As a result, the electrical properties of the Ca(1 - x)Sr(x)IrO(3) films are found to be sensitive to x and strain.

Treatment of Symptomatic Intracranial Atherosclerotic Stenosis with a Normal-Sized Gateway™ Balloon and Wingspan™ Stent

The safety and performance of angioplasty using a normal-sized Gateway™ balloon and Wingspan™ stent for intracranial atherosclerotic stenosis were assessed. Seventy-two patients with intracranial stenosis (≥ 50%) were treated using an undersized (group U) or normal-sized (group N) Gateway™ balloon and a Wingspan™ stent. All patients were successfully stented. Stenosis improved from 74.2% before treatment to 23.8% immediately after treatment in group U and from 70.9% to 20.1% in group N. The two groups had similar rates of major periprocedural neurological complications (9.0% overall), none of which led to death. Residual stenosis at follow-up was 40.8% and 32.5% in groups U and N, respectively. In-stent re-stenosis (ISR) was significantly less frequent in group N (22.0%) than in group U (33.3%). It is concluded that use of a normal-sized Gateway™ balloon and Wingspan™ stent appears to be safe, to have a high rate of technical success, good immediate post-operative results and a low ISR rate.

Search for diphoton events with large missing transverse energy in 6.3 fb(-1) of pp collisions at √s=1.96 TeV

We report a search for diphoton events with large missing transverse energy produced in pp collisions at √s=1.96  TeV. The data were collected with the D0 detector at the Fermilab Tevatron Collider and correspond to 6.3  fb(-1) of integrated luminosity. The observed missing transverse energy distribution is well described by the standard model prediction, and 95% C.L. limits are derived on two realizations of theories beyond the standard model. In a gauge-mediated supersymmetry breaking scenario, the breaking scale Λ is excluded for Λ<124  TeV. In a universal extra dimension model including gravitational decays, the compactification radius R(c) is excluded for R(c)(-1)<477  GeV.

Search for new fermions ("quirks") at the Fermilab Tevatron collider

We report results of a search for particles with anomalously high ionization in events with a high transverse energy jet and large missing transverse energy in 2.4 fb⁻¹ of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron pp collider. Production of such particles (quirks) is expected in scenarios with extra QCD-like SU(N) sectors, and this study is the first dedicated search for such signatures. We find no evidence of a signal and set a lower mass limit of 107, 119, and 133 GeV for the mass of a charged quirk with strong dynamics scale Λ in the range from 10 keV to 1 MeV and N=2, 3, and 5, respectively.

Search for events with leptonic jets and missing transverse energy in pp collisions at √s=1.96 TeV

We present the first search for pair production of isolated jets of charged leptons in association with a large imbalance in transverse energy in pp collisions using 5.8 fb⁻¹ of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider. No excess is observed above the standard model background, and the result is used to set upper limits on the production cross section of pairs of supersymmetric chargino and neutralino particles as a function of "dark-photon" mass, where the dark photon is produced in the decay of the lightest supersymmetric particle.

Search for sneutrino production in eμ final states in 5.3 fb-1 of pp collisions at square root s =1.96 TeV

We report the results of a search for R parity violating (RPV) interactions leading to the production of supersymmetric sneutrinos decaying into eμ final states using 5.3 fb-1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. Having observed no evidence for production of eμ resonances, we set direct bounds on the RPV couplings λ311' and λ312 as a function of sneutrino mass.

Intravenous administration of bone marrow mesenchymal stem cells benefits experimental autoimmune myasthenia gravis mice through an immunomodulatory action

Mesenchymal stem cells (MSC) are potent in immunomodulation. It has been proven that MSC functioned to correct immune disorder in several immune diseases. Here, we tested the hypothesis that MSC from human bone marrow (hMSC) can provide a potential therapy for experimental autoimmune myasthenia gravis (EAMG). EAMG mice model was established by subcutaneous injection of synthetic analogue of acetylcholine receptor (AchR), then, hMSC were intravenously delivered into these mice repeatedly. The results showed that hMSC could specifically home to spleen tissue and hMSC treatment significantly improved the functional deficits of EAMG mice. In addition, AchR antibody level was dramatically decreased in cell-treated group when compared with untreated control on 10 days after the second cell injection. Moreover, both in vivo and in vitro mixed lymphocyte proliferation assays revealed that hMSC could definitely inhibit the proliferation of AchR-specific lymphocyte. In conclusion, our study demonstrated that hMSC treatment was therapeutically useful in autoimmune myasthenia gravis mice, and the underlying mechanism may relate with their immunomodulatory potential.

Cautionary note: linewidth effect in dynamic NMR

In using NMR spectroscopy to evaluate the effects of kinetic processes taking place in the solute molecules being studied, one must estimate the inherent width w of each line, which is hidden from view throughout the kinetic thermal region due to the line-width broadening effected by the processes. We have herein built a self-consistent model function w(T) to attempt to evaluate the variation in the Arrhenius activation energy obtained with the model parameters present in w(T). As it turns out, a sizable number of such line-width parameters yields excellent spectral fits, and these lead to a considerable range of possible activation energies.