Development of a fluorescent in situ hybridization (FISH) technique for visualizing CGMMV in plant tissues.

Cucumber green mottle mosaic virus (CGMMV), which belongs to the genus Tobamovirus, is a major pathogen of cucurbit crops grown indoors and in open fields. Currently, immunology (e.g., ELISA) and molecular amplification techniques (e.g., RT-PCR) are employed extensively for virus detection in plant tissues and commercial seed lots diagnostics. In this study, a fluorescent in situ hybridization (FISH) technique, using oligonucleotides whose 5'-terminals were labeled with red cyanine 3 (Cy3) or green fluorescein isothiocyanate (FITC), was developed for the visualization of the pathogen in situ. This simple and reliable method allows detection and localization of CGMMV in the vegetative and reproductive tissues of cucumber and melon. When this technique was applied in male flowers, anther tissues were found to be infected; whereas the pollen grains were found to be virus-free. These results have meaningful epidemiological implications for the management of CGMMV, particularly with regard to virus transfer via seed and the role of insects as CGMMV vectors.

Arteriogenic expansion of extratumoral macrovessels - impact of vascular ageing.

The critical role of the vasculature in cancer progression is predominantly studied at the capillary level, and often equated with angiogenesis. However, the mechanisms that ensure the supply of increasing blood volume to the expanding tumor microcirculation remain presently unclear. Here we used established mouse tumor models to document the enlargement (arteriogenesis), of macroscopic feeding vessels at considerable distances upstream from the malignant lesion, but not contralaterally. These changes are not affected by the procoagulant host tissue factor (TF), but are modulated by vascular ageing and atherosclerosis in ApoE-/- mice. Moreover, arteriogenic growth involves infiltration of bone marrow derived (YFP-labeled) cells and changes the gene expression profiles in the vessel wall. Thus, our observations suggest that in addition to local angiogenesis tumors influence distant remodeling of regional macroscopic blood vessels in a manner that is modulated by certain vascular comorbidities.

Neuropeptide and neurohormone precursors in the pea aphid, Acyrthosiphon pisum.

Aphids respond to environmental changes by developing alternative phenotypes with differing reproductive modes. Parthenogenetic reproduction occurs in spring and summer, whereas decreasing day lengths in autumn provoke the production of sexual forms. Changing environmental signals are relayed by brain neuroendocrine signals to the ovarioles. We combined bioinformatic analyses with brain peptidomics and cDNA analyses to establish a catalogue of pea aphid neuropeptides and neurohormones. 42 genes encoding neuropeptides and neurohormones were identified, of which several were supported by expressed sequence tags and/or peptide mass analyses. Interesting features of the pea aphid peptidome are the absence of genes coding for corazonin, vasopressin and sulfakinin and the presence of 10 different genes coding insulin related peptides, one of which appears to be very abundantly expressed.

Aphid transmission of a potyvirus depends on suitability of the helper component and the N terminus of the coat protein.

The present study investigates the specificity of potyviruses for aphid species. Two potyviruses differing in their host range were used: Zucchini yellow mosaic virus (ZYMV) mainly infecting cucurbits and Turnip mosaic virus (TuMV) mainly infecting crucifers. Two sets of aphids species were used as vectors, one polyphagous (Myzus persicae and Aphis gossypii) and the other from crucifers (Brevicoryne brassicae and Lipaphis erysimi). Evidence is provided that the specificity between a vector and a potyvirus depends either on the affinity between the aphid species and the helper component (HC) protein used or on the affinity between the HC and the virions. The difference between the two potyviruses cannot be attributed to the DAG domain which is unaltered in both N termini of the CP. Therefore, a ZYMV full length clone served to exchange a fragment encoding for the N terminus of the ZYMV CP by that of TuMV. This partial exchange in the ZYMV CP, allowed the TuMV HC to transmit the chimeric virus but not the wild type ZYMV. The significance of the N terminus context of the CP in the specificity for the HC is discussed.

Comparison of newly isolated cuticular protein genes from six aphid species.

This paper reports on the first aphids' cuticular proteins. One gene (Mpcp1) was obtained by screening a cDNA library of Myzus persicae with antibodies to a lepidopteran cuticle protein. MpCP1 presents a putative signal peptide, a central extended R&R domain, flanked by N- and C-terminal repeats of alanine, tyrosine and proline. The mRNA of Mpcp1 could be detected in a larval and in adult stages. Primers based on Mpcp1 allowed isolating and comparing cuticle protein genes from five aphid species, but not from whitefly or thrips. Comparison revealed a high degree of similarity. Data from this paper suggest that this cuticle protein family is typical and predominant to aphids. The conformation of these cuticle proteins and the significance on particular properties of aphid cuticle is discussed.

Tax-independent stimulation of human T-cell leukemia virus type-I expression and differential effects on its infectivity by subtoxic and toxic doses of 3-methylcholanthrene.

Using the human T-cell leukemia virus type I (HTLV-I) infected SLB-I T-cell line, we showed in this study that 5-d treatment with the maximal subtoxic 3-methylcholanthrene (3-MC) dose (0.25 microgram/ml), as well as with a 3-MC dose that inhibits 50% of the cell growth (5 micrograms/ml), profoundly increased the level of viral RNA. Exposure to these 3-MC doses for 5 d before transient transfection of HTLV-I LTR-CAT construct into these cells markedly stimulated CAT activity, indicating that 3-MC exerted its effect by a trans-acting mechanism. A similar stimulation was observed when this construct was transfected into 3-MC treated uninfected Jurkat cells, indicating that this trans-acting effect was independent of the viral tax protein. However, although the subtoxic 3-MC dose increased also the capacity of SLB-I cells to transmit the virus to normal peripheral blood lymphocytes in coculture, the toxic dose strongly reduced this capacity. No inhibition by this toxic dose was observed in the viral protein synthesis or processing nor in the final release of the virus from the cells. However, the virions released under the influence of this 3-MC dose were found to contain mainly the uncleaved gag precursor polypeptide and a low level of reverse transcriptase. Thus, the reduced virus transmission capacity of the host cells can be ascribed to this structural defect, which presumably lowered the viral infectivity.