Host-specific effect of P1 exchange between two potyviruses

The potyviruses Plum pox virus (PPV) and Tobacco vein mottling virus (TVMV) have distinct host ranges and induce different symptoms in their common herbaceous hosts. To test the relevance of the P1 protein in host compatibility and pathogenicity, hybrid viruses were constructed in which the P1 coding sequence of PPV was completely or partially replaced by the corresponding sequences from TVMV. Infections induced by these chimeric viruses revealed that the TVMV P1 and a PPV/TVMV hybrid P1 proteins are functionally equivalent in herbaceous plants to the P1 protein of a PPV isolate adapted to these hosts, in spite of having high sequence divergence. Moreover, the presence of TVMV P1 sequences enhanced the competence of a low-infectivity PPV-D-derived chimera in Nicotiana clevelandii . Conversely, all PPV/TVMV hybrids were unable to infect Prunus persicae , a specific host for PPV, suggesting that TVMV P1 is not functionally competent in this plant. Together, these data highlight the importance of the P1 protein in defining the virus host range.     

Waisel, Y., Eshel, A., Kafkafi, U., eds. Plant roots - the hidden half

Research on plant roots represents an exciting and intriguingfield of science. Undoubtedly, the vast major ity of researcherswithin the field are familiar with the first (1991) and second(1996) editions of this book. Since these editions were published,understanding of root biology has been advanced by using molecularbiology methods and molecular genetic tools which offer novelperspectives for the exploitation and understanding of rootstructure and root processes. The third edition of Plant roots– the hidden half includes revised and expanded informationon topics covered in the previous editions, as well as in     

Peroxidase catalyzed microbiological oxidation of isosafrol into piperonal

A detailed and reliable bioassay to detect peroxidase activity in order to select microbial catalytic agents capable to oxidize isosafrol, 4-(1′-propene)-1,2-methylenedioxybenzene, into piperonal, 4-carboxaldehyde-1,2-methylenedioxibenzene is fully described. The systematic methodology was divided into two parts: first peroxidase activity in microbial systems was detected and determined via the guaiacol assay method and secondly, a biotransformation process to oxidize the substrate was developed. Investigation assays to detect peroxidase activities were performed by using UV-Vis spectrometry, while product formation was monitored by gas chromatography. The biooxidative peroxidase catalyzed transformation of isosafrol into piperonal was achieved with 20% conversion.     

Cordiachromes from Auxemma oncocalyx

Further cordiachromes, rel-10,11β-epoxy-11-ethoxy-8-hydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10aβ-octahydro-1,4-anthracendione, 6-formyl-2-methoxy-9-methyl-7,8-dihydro-1,4-phenanthrendione, rel-8,11;9,11-diepoxy-1,4-dihydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10,10aβ-octahydro-10-anthracenone, rel-9,11-epoxy-1,4,8-trihydroxy-2-methoxy-8aβ-methyl-5,6,7,8,8a,9,10,10aβ-octahydro-10-anthracenone, rel-2″-methoxy-7″-methyl-1″,4″-naphtalendione-(6″→5)-tetrahydropyran-(2-eq→O→2ax)-tetrahydropyran-(5′→6)- 2-methoxy-7-methyl-1,4-naphthalendione, together with the known, allantoin, sitosterol and 3β-O-d-glucopyranosylsitosterol, have been isolated from Auxemma oncocalyx. Their structures were determined from spectral data, including 2D NMR experiments.     

The temperature-dependent self-association of beta-lactoglobulin C in glycine buffers

The self-association of β-lactoglobulin C at low pH (ca. 2.5) in glycine buffers has been studied at four temperatures, 10, 16, 20, and 25 °C, by low- and high-speed sedimentation equilibrium experiments. One buffer had an ionic strength of 0.1 and the other an ionic strength of 0.2. With either buffer the concentration dependence of the apparent weight average molecular weight, M_wa, was characteristic of a nonideal self-association. Like its genetic variants, β-lactoglobulin A and B, the self-association of β-lactoglobulin C increased with decreasing temperature; however, at the same temperature the association was always stronger in the buffer having the higher ionic strength. Several models were used to test the self-association, and a monomer-dimer self-association seemed to describe the self-association best with either buffer. Values of the association equilibrium constant, K₂, and the second virial coefficient, BM₁, are reported at each temperature for both series of experiments. Values of the thermodynamic functions, ΔG °, ΔH °, and ΔS °, are also reported for these experiments.     

Virus‐induced gene silencing in transgenic plants: transgene silencing and reactivation associate with two patterns of transgene body methylation

We used bisulfite sequencing to study the methylation of a viral transgene whose expression was silenced upon plum pox virus infection of the transgenic plant and its subsequent recovery as a consequence of so‐called virus‐induced gene silencing (VIGS). VIGS was associated with a general increase in the accumulation of small RNAs corresponding to the coding region of the viral transgene. After VIGS, the transgene promoter was not methylated and the coding region showed uneven methylation, with the 5′ end being mostly unmethylated in the recovered tissue or mainly methylated at CG sites in regenerated silenced plants. The methylation increased towards the 3′ end, which showed dense methylation in all three contexts (CG, CHG and CHH). This methylation pattern and the corresponding silenced status were maintained after plant regeneration from recovered silenced tissue and did not spread into the promoter region, but were not inherited in the sexual offspring. Instead, a new pattern of methylation was observed in the progeny plants consisting of disappearance of the CHH methylation, similar CHG methylation at the 3′ end, and an overall increase in CG methylation in the 5′ end. The latter epigenetic state was inherited over several generations and did not correlate with transgene silencing and hence virus resistance. These results suggest that the widespread CG methylation pattern found in body gene bodies located in euchromatic regions of plant genomes may reflect an older silencing event, and most likely these genes are no longer silenced.     

Resprouting Ability of Six Atlantic Shrub Species

Resprouting from subterranean structures is a principal method of vegetative regeneration that many shrub species show after a disturbance. This study, therefore, aims to determine the resprouting capacity and intensity of six dominant species in an Atlantic shrubland area located in the NW of the Iberian Peninsula and compare their resprouting and germinating strategies. Resprouting intensity is measured using three variables: individual probability of resprouting, number of resprouts and length of these sprouts in three plant-age classes. The intensity for each species was calculated using a simple index (IRI) that included the three measured variables. All studied species, excepting Erica umbellata, could resprout. According to the IRI values, there are three groups of species: strong resprouters (Ulex europaeus, Ulex minor and Pterospartum tridentatum), weak resprouters (Ulex micranthus and Genista triacanthos) and non-resprouters (E. umbellata). The germination of strong resprouters is highly stimulated by fire. Frequent disturbances remove the non- and weak resprouter populations and promote the strong resprouter ones.     

Immunomodulatory effects of alcbholic and hydroalcoholic extracts of Moringa olifera Lam leaves

Effects of 50, 100 and 200 mg/kg body weight of the alcoholic and hydro-alcoholic extract of leaves of M. olifera were studied on various immune paradigms like delayed type hypersensitivity reaction using SRBC as an antigen, determination of antibody titer, neutrophil adhesion test as an indicator for neutrophil index, total leucocyte count in cyclophosphamide induced immunosuppressed animals and carbon clearance assay as a measure of phagocytic activity. Hydro-alcoholic extract of M. olifera substantially enhanced cellular immune response, humoral immune response, neutrophil index and phagoctic activity in doses of 100 and 200 mg/kg body weight. The ethanolic extract (200 mg/kg body weight) was efficient in improving immune response. The results suggest that M. olifera has a significant role to play as an immune stimulator.     

FAPP2 is involved in the transport of apical cargo in polarized MDCK cells

Phosphatidylinositol-4-phosphate (PI(4)P) is the main phosphoinositide in the Golgi complex and has been reported to play a pleiotropic role in transport of cargo from the trans-Golgi network to the plasma membrane (PM) in polarized Madin-Darby canine kidney (MDCK) cells. Overexpression of the chimeric fluorescent protein encoding the pleckstrin homology domain, which is specific for PI(4)P, inhibited both apical and basolateral transport pathways. The transport of apical cargo from the Golgi was shown to be specifically decreased by adenovirus-mediated RNA interference directed against PI(4)P adaptor protein (FAPP) 2. FAPP1 depletion had no effect on transport. On the other hand, FAPP2 was not involved in the Golgi-to-PM transport of cargo that was targeted to the basolateral membrane domain. Thus, we conclude that FAPP2 plays a specific role in apical transport in MDCK cells.     

Austral Yungas under future climate and land-use changes scenarios: the importance of protected areas for long-term amphibian conservation

Biodiversity and Conservation - We estimated the potential distribution for 31 amphibian species inhabiting the threatened Austral Yungas under current and future climate projections (2050’s)...