Resistance to Plasmopara viticola in a grapevine segregating population is associated with stilbenoid accumulation and with specific host transcriptional responses

BACKGROUND

Downy mildew, caused by the oomycete Plasmopara viticola, is a serious disease in Vitis vinifera, the most commonly cultivated grapevine species. Several wild Vitis species have instead been found to be resistant to this pathogen and have been used as a source to introgress resistance into a V. vinifera background. Stilbenoids represent the major phytoalexins in grapevine, and their toxicity is closely related to the specific compound. The aim of this study was to assess the resistance response to P. viticola of the Merzling × Teroldego cross by profiling the stilbenoid content of the leaves of an entire population and the transcriptome of resistant and susceptible individuals following infection.

RESULTS

A three-year analysis of the population's response to artificial inoculation showed that individuals were distributed in nine classes ranging from total resistance to total susceptibility. In addition, quantitative metabolite profiling of stilbenoids in the population, carried out using HPLC-DAD-MS, identified three distinct groups differing according to the concentrations present and the complexity of their profiles. The high producers were characterized by the presence of trans-resveratrol, trans-piceid, trans-pterostilbene and up to thirteen different viniferins, nine of them new in grapevine.Accumulation of these compounds is consistent with a resistant phenotype and suggests that they may contribute to the resistance response.A preliminary transcriptional study using cDNA-AFLP selected a set of genes modulated by the oomycete in a resistant genotype. The expression of this set of genes in resistant and susceptible genotypes of the progeny population was then assessed by comparative microarray analysis.A group of 57 genes was found to be exclusively modulated in the resistant genotype suggesting that they are involved in the grapevine-P. viticola incompatible interaction. Functional annotation of these transcripts revealed that they belong to the categories defense response, photosynthesis, primary and secondary metabolism, signal transduction and transport.

CONCLUSIONS

This study reports the results of a combined metabolic and transcriptional profiling of a grapevine population segregating for resistance to P. viticola. Some resistant individuals were identified and further characterized at the molecular level. These results will be valuable to future grapevine breeding programs.

Profiling of resveratrol oligomers, important stress metabolites, accumulating in the leaves of hybrid Vitis vinifera (Merzling × Teroldego) genotypes infected with Plasmopara viticola

In the Vitaceae, viniferins represent a relatively restricted group of trans-resveratrol oligomers with antifungal properties, thus enabling plants to cope with pathogen attack. The aim of this study was to perform isolation and structural characterization of the whole class of viniferins accumulating in the leaves of hybrid Vitis vinifera (Merzling × Teroldego) genotypes infected with Plasmopara viticola . Infected leaves of resistant plants were collected 6 days after infection, extracted with methanol, and prepurified by flash chromatography using ENV+ and Toyopearl HW 40S resins. Further fractionation using normal-phase preparative chromatography and then reversed-phase preparative chromatography allowed isolation of 14 peaks. The isolated compounds were identified using advanced mass spectrometry techniques and extensive one- and two-dimensional nuclear magnetic resonance measurements, UV, CD, optical properties, and molecular mechanic calculations. The results demonstrated the presence in infected leaves of seven dimers (six stilbenes and one stilbenoid), of which four were new in grapevine (ampelopsin D, quadrangularin A, E-ω-viniferin, and Z-ω-viniferin), four trimers (three stilbenes and one stilbenoid), of which two (Z-miyabenol C and E-cis-miyabenol C) were new in grapevine, three tetramer stilbenoids, all new in grapevine, isohopeaphenol, ampelopsin H, and a vaticanol C-like isomer. The isolation of a dimer deriving from the condensation of (+)-catechin with trans-caffeic acid also indicated that other preformed phenolics are structurally modified in tissues infected with P. viticola.

Genetic correlation in relation to differences in dosage of a stressor

We exposed the strains of Chlamydomonas isolated from an outbred laboratory population to a range of concentrations of salt (NaCl) up to an extirpative level that the base population could not tolerate. The genetic variance of yield increased with stress over the first half of this range before collapsing to nearly zero. The genetic correlation decreased with environmental distance, whether measured as a difference in dosage or as an environmental variance. This result is consistent with previous studies and provides a basis for interpreting adaptation to a deteriorating environment and the process of evolutionary rescue.

Austrian syndrome

The authors present a case of Austrian syndrome, the triad of pneumococcal pneumonia, endocarditis and meningitis, in a 49-year-old woman, who developed severe acute heart failure due to aortic valve destruction. The patient required imminent valve surgery, but eventually recovered.

Effects of ASA404, a vascular disrupting agent, on tumor growth of gastric cancer in an experimental model

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Background: A functional vascular system is essential for growth of solid malignancies including gastric cancer. For establishment and maintenance of such a vascular system endothelial cells (ECs) and pericytes (e.g. vascular smooth muscle cells, VSMC) are required. We hypothesized that targeting tumor vasculature with the vascular disrupting agent (VDA) ASA404 (Novartis Oncology) reduces tumor growth in a model of gastric cancer.

Methods: Gastric cancer (GC) cell lines, ECs and VSMCs were used for experiments. Effects of ASA404 on growth of GC, EC and VSMC were assessed by MTT assays. Impact of ASA404 (20 mg/kg on day 1, 5, 9) in combination with paclitaxel (10 mg/kg on day 1 and 7) on tumor growth was assessed in a subcutaneous tumor model. Treatment was started when tumors reached a size of approximately 200 mm3. Tumors were measured and harvested on day 23 for IHC analyses. Effect of ASA404 on blood perfusion of tumors during therapy was monitored by contrast-enhanced ultrasound (CEUS).

Results: In vitro ASA404 impaired growth of ECs and VSMCs upon stimulation with condition media from gastric cancer cells. No direct effect on tumor cells was observed. In vivo, treatment with ASA404 led to marked decrease of tumor perfusion and an increase of necrosis as determined by CEUS. Furthermore, combination of ASA404 with paclitaxel showed significant reduction of tumor growth compared to controls (p < 0.05). In addition, tumor vascularisation and tumor cell proliferation were significantly reduced as determined by CD31-positive vessel area and BrdU-positive cells (p < 0.05).

Conclusions: Combination of the VDA ASA404 with paclitaxel impairs tumor growth and perfusion of gastric cancer in an experimental model. Hence, targeting tumor vasculature with ASA404 appears to be a promising strategy for therapy of gastric cancer.

No significant financial relationships to disclose.

Signal transducer and activator of transcription 5b (STAT5b) as a novel target for anti-neoplastic therapy in human pancreatic cancer

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Background: Activation of signal transducer and activator of transcription 5b (STAT5b) has been associated with tumor growth and metastases in various tumor entities. A number of cytokines, growth factors, and oncogenes that can induce STAT5b activity are also implicated in pancreatic cancer growth and metastases. Hence, we sought to determine STAT5b expression in human pancreatic cancer specimen and effects of selective STAT5b inhibition on pancreatic cancer cells.

Methods: Expression of STAT5b in human pancreatic adenocarcinomas was determined by immunohistochemistry. For in vitro experiments, human pancreatic cancer cell lines (BxPC-3, HPAF-II, L3.6pl) were used. Cancer cells were transfected with STAT5b shRNA plasmid to create stable STAT5b knock-down. Effects of STAT5b inhibition on growth and motility of tumor cells was investigated by MTT and modified Boyden chamber assays. In vivo effects of STAT5b blockade were determined in subcutaneous mouse model.

Results: Nuclear expression of STAT5b was detected in 42/80 human pancreatic adenocarcinomas. In human cancer cell lines, stable knock-down of STAT5b had no effect on growth of tumor cells in vitro. However, tumor cell motility was significantly reduced upon STAT5b blockade (p<0.05). Moreover, expression of various signaling intermediates and transcription factors including c-myc was impaired upon STAT5b knock-down. In a subcutaneous tumor model, inhibition of STAT5b led to significantly reduced tumor growth (p<0.05) which was also reflected by final tumor weights (p<0.05). Furthermore, as revealed by immunohistochemistry, blockade of STAT5b significantly reduced tumor vascularization in vivo (p<0.05).

Conclusions: STAT5b is expressed in human pancreatic adenocarcinomas. Blockade of STAT5b impairs cancer cell motility in vitro, suggesting antimetastatic potential. Moreover, inhibition of STAT5b significantly reduces tumor growth and tumor vascularization in vivo. Hence, STAT5b might be an interesting target for antineoplastic therapy in human pancreatic cancer.

No significant financial relationships to disclose.

Armillaria mellea induces a set of defense genes in grapevine roots and one of them codifies a protein with antifungal activity

Grapevine root rot, caused by Armillaria mellea, is a serious disease in some grape-growing regions. Young grapevines start to show symptoms of Armillaria root rot from the second year after inoculation, suggesting a certain degree of resistance in young roots. We used a suppression subtractive hybridization approach to study grapevine's reactions to the first stages of A. mellea infection. We identified 24 genes that were upregulated in the roots of the rootstock Kober 5BB 24 h after A. mellea challenge. Real-time reverse-transcriptase polymerase chain reaction analysis confirmed the induction of genes encoding protease inhibitors, thaumatins, glutathione S-transferase, and aminocyclopropane carboxylate oxidase, as well as phase-change related, tumor-related, and proline-rich proteins, and gene markers of the ethylene and jasmonate signaling pathway. Gene modulation was generally stronger in Kober 5BB than in Pinot Noir plants, and in vitro inoculation induced higher modulation than in greenhouse Armillaria spp. treatments. The full-length coding sequences of seven of these genes were obtained and expressed as recombinant proteins. The grapevine homologue of the Quercus spp. phase-change-related protein inhibited the growth of A. mellea mycelia in vitro, suggesting that this protein may play an important role in the defense response against A. mellea.

Cloning and characterization of small non-coding RNAs from grape

Small non-coding RNAs, including microRNAs (miRNAs) and small interfering RNAs (siRNAs), are effectors of regulatory pathways underlying plant development, metabolism, and responses to biotic and abiotic stresses. To address the nature and functions of these regulators in grapevine (Vitis vinifera L.), we have produced a small RNA library from mixed-stage grape berries. Thirteen conserved miRNAs belonging to nine miRNA families, a non-conserved miRNA, and four putative non-conserved miRNAs were isolated, and their expression and targets are described. Experimentally validated targets of non-conserved miRNAs and putative miRNAs included three genes encoding NB-LRR proteins and a gene encoding a heavy metal ion transport/detoxification protein. Of the endogenous and pathogen-derived siRNAs that were also isolated, four endogenous siRNAs mapped to genes encoding RD22-like proteins and two to a gene encoding a cytokinin synthase. The siRNA id65 targeted the cytokinin synthase gene transcript with antisense complementarity, and was specifically expressed in mature berries, in which, by contrast, expression of the cytokinin synthase gene was strongly repressed. 5' RACE revealed that the transcript of this gene was processed in 21 nucleotide increments from the id65 cleavage site, and that further cleavage was mediated by secondary siRNAs in cis. These results indicate that grapevine miRNA- and siRNA-mediated regulatory circuits have evolved to comprise processes associated with defence and fruit ripening, and broaden the range of small RNA-mediated regulation, which was previously associated with auxin, ABA, gibberellins and jasmonate, to encompass cytokinin metabolism.

[Classification of the arabidopsis ERF gene family based on Bayesian analysis]

ERF proteins are essential transcriptional regulators of different cellular functions such as response to biotic and abiotic stresses, metabolism and development. They belong to the AP2/ERF gene superfamily of transcription factors and are characterized by the presence of a conserved AP2/ERF DNA binding domain in their sequence. A detailed phylogeny based classification of the ERF genes is important because it gives insights into the function of the different members and sub-groups of the family. We check here the classification of the Arabidopsis thaliana ERF protein family based on the NJ tree built from the protein distance matrix proposed by Nakano and collaborators, employing Bayesian Inference (BI) with the substitution model fitted to the coding sequences of the conserved DNA-binding AP2/ERF domain. We expanded the dataset used by Nakano et al. for phylogeny reconstruction by including the so called VI-like and X-like groups. Our analysis could not confirm the close affinity of these groups to the groups VI and X, suggested in the original analysis so we propose to treat them as new groups XI and XII. Groups VI and IX suggested by Nakano et al. could also not be confirmed, as they appeared as paraphyletic assemblages in our analysis. All other groups suggested by Nakano et al, appeared as monophyla also in our BI tree. Our findings will contribute to the functional characterization of the genes belonging to the ERF family.

Grapevine cell early activation of specific responses to DIMEB, a resveratrol elicitor

BACKGROUND

In response to pathogen attack, grapevine synthesizes phytoalexins belonging to the family of stilbenes. Grapevine cell cultures represent a good model system for studying the basic mechanisms of plant response to biotic and abiotic elicitors. Among these, modified beta-cyclodextrins seem to act as true elicitors inducing strong production of the stilbene resveratrol.

RESULTS

The transcriptome changes of Vitis riparia x Vitis berlandieri grapevine cells in response to the modified beta-cyclodextrin, DIMEB, were analyzed 2 and 6 h after treatment using a suppression subtractive hybridization experiment and a microarray analysis respectively. At both time points, we identified a specific set of induced genes belonging to the general phenylpropanoid metabolism, including stilbenes and hydroxycinnamates, and to defence proteins such as PR proteins and chitinases. At 6 h we also observed a down-regulation of the genes involved in cell division and cell-wall loosening.

CONCLUSIONS

We report the first large-scale study of the molecular effects of DIMEB, a resveratrol inducer, on grapevine cell cultures. This molecule seems to mimic a defence elicitor which enhances the physical barriers of the cell, stops cell division and induces phytoalexin synthesis.

Gene expression profiling in susceptible interaction of grapevine with its fungal pathogen Eutypa lata: extending MapMan ontology for grapevine

BACKGROUND

Whole genome transcriptomics analysis is a very powerful approach because it gives an overview of the activity of genes in certain cells or tissue types. However, biological interpretation of such results can be rather tedious. MapMan is a software tool that displays large datasets (e.g. gene expression data) onto diagrams of metabolic pathways or other processes and thus enables easier interpretation of results. The grapevine (Vitis vinifera) genome sequence has recently become available bringing a new dimension into associated research. Two microarray platforms were designed based on the TIGR Gene Index database and used in several physiological studies.

RESULTS

To enable easy and effective visualization of those and further experiments, annotation of Vitis vinifera Gene Index (VvGI version 5) to MapMan ontology was set up. Due to specificities of grape physiology, we have created new pictorial representations focusing on three selected pathways: carotenoid pathway, terpenoid pathway and phenylpropanoid pathway, the products of these pathways being important for wine aroma, flavour and colour, as well as plant defence against pathogens. This new tool was validated on Affymetrix microarrays data obtained during berry ripening and it allowed the discovery of new aspects in process regulation. We here also present results on transcriptional profiling of grape plantlets after exposal to the fungal pathogen Eutypa lata using Operon microarrays including visualization of results with MapMan. The data show that the genes induced in infected plants, encode pathogenesis related proteins and enzymes of the flavonoid metabolism, which are well known as being responsive to fungal infection.

CONCLUSION

The extension of MapMan ontology to grapevine together with the newly constructed pictorial representations for carotenoid, terpenoid and phenylpropanoid metabolism provide an alternative approach to the analysis of grapevine gene expression experiments performed with Affymetrix or Operon microarrays. MapMan was first validated on an already published dataset and later used to obtain an overview of transcriptional changes in a susceptible grapevine - Eutypa lata interaction at the time of symptoms development, where we showed that the responsive genes belong to families known to be involved in the plant defence towards fungal infection (PR-proteins, enzymes of the phenylpropanoid pathway).

Autologous conditioned serum (Orthokine) is an effective treatment for knee osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is prevalent and difficult to treat. Autologous conditioned serum (ACS), marketed under the trade name Orthokine, is a novel, injectable antiarthritic derived from the patient's own blood. The present study is the first time ACS has undergone a controlled clinical trial.

METHOD

We investigated 376 patients with knee OA in a prospective, randomized, patient- and observer-blinded, placebo-controlled trial using an intention-to-treat analysis (ITT). The clinical effects of ACS were compared to hyaluronan (HA) and saline (placebo) as assessed by patient-administered outcome instruments (Western Ontario and McMaster Universities osteoarthritis index, global patient assessment, visual analog scale, Short-Form 8) after 7, 13 and 26 weeks. After 104 weeks an observer-blinded follow-up was carried out. Frequency and severity of adverse events were used as safety parameters.

RESULTS

In all treatment groups, intra-articular injections produced a reduction in symptoms as well as an improvement in quality of life. However, the effects of ACS were significantly superior to those of HA and saline for all outcome measures and time points, and improvements were clinically relevant; there were no differences between the effects of HA and saline. The frequency of adverse events was comparable in the ACS and saline groups, but higher in the HA group.

CONCLUSION

The data demonstrate that ACS injection considerably improves clinical signs and symptoms of OA. It remains to be determined whether ACS is disease-modifying, chondroprotective, or chondroregenerative.

Ripening and genotype control stilbene accumulation in healthy grapes

In grapes, stilbene synthesis occurs in the skin, and it is induced by biotic and abiotic stresses. To date, experimental evidence of a constitutive production of resveratrols in healthy grape is scarce and not conclusive. The aim of the present work was to investigate stilbene biosynthesis in healthy grapes both at biochemical and molecular levels. By measuring the concentration of resveratrols in ripe berries of 78 Vitis vinifera varieties for 3 years, we could identify significant differences among genotypes, providing the first tentative varietal classification based on resveratrol content. Furthermore, an increasing stilbene accumulation from veraison to ripening phase was also observed. Using real-time reverse transcription polymerase chain reaction and a berry-specific cDNA array, gene expression analysis was carried out on two distinct pools of berries belonging to the high and low resveratrol producers and on three berry developmental stages. The stilbene synthase, phenylalanine ammonia-lyase, and 4-coumarate-CoA ligase expression profiles showed an increasing concentration of these transcripts from véraison to maturity and a higher accumulation in the grape of high resveratrol producers. Macroarray data analysis revealed that high resveratrol levels are also accompanied by the up-regulation of genes involved in plant defense and the concomitant underexpression of genes related to the ripening process and to indole alkaloid synthesis.

Thermal injury induces impaired function in polymorphonuclear neutrophil granulocytes and reduced control of burn wound infection

Severe thermal injury induces immunosuppression, involving all parts of the immune system, especially when large fractions of the total body surface area are affected. An animal model was established to characterize the burn-induced immunosuppression. In our novel mouse model a 6% third-degree burn injury was induced in mice with a hot-air blower. The third-degree burn was confirmed histologically. The mice were allocated into five groups: control, shave, burn, infection and burn infection group. At 48 h, a decline in the concentration of peripheral blood leucocytes was observed in the group of mice with burn wound. The reduction was ascribed to the decline in concentration of polymorphonuclear neutrophil leucocytes and monocytes. When infecting the skin with Pseudomonas aeruginosa, a dissemination of bacteria was observed only in the burn wound group. Histological characterization of the skin showed a more polymorphonuclear neutrophil granulocytes (PMNs)-dominated inflammation in the group of mice with infected burn wound compared with the with burn wound group. In contrast, a higher degree of inflammation was observed in the burn wound group compared with the group of mice with infected burn wound. Furthermore, the oxidative burst and the phagocytic capacity of the PMNs were reduced in the group of mice with burn wound. Using this novel mouse model of thermal injury a decline of peripheral leucocytes was observed, whereas the increased local inflammatory response at the site of infection showed reduced capacity to contain and eliminate the infection.

Autologous fibrin sealant reduces the incidence of prolonged air leak and duration of chest tube drainage after lung volume reduction surgery: a prospective randomized blinded study

OBJECTIVE

Prolonged air leak is reported in up to 50% of patients after lung volume reduction surgery. The effect of an autologous fibrin sealant on the intensity and duration of air leak and on the time to chest drain removal after lung volume reduction surgery was investigated in a randomized prospective clinical trial.

METHODS

Twenty-five patients underwent bilateral thoracoscopic lung volume reduction surgery. In each patient, an autologous fibrin sealant was applied along the staple lines on one side, whereas no additional measure was taken on the other side. Randomization of treatment was performed at the end of the resection on the first side. Air leak was assessed semiquantitatively by use of a severity score (0 = no leak; 4 = continuous severe leak) by two investigators blinded to the treatment.

RESULT

Mean value of the total severity scores for the first 48 hours postoperative was significantly lower in the treated group (4.7 +/- 7.7) than in the control group (16.0 +/- 10.1) (P < .001), independently of the length of the resection. Prolonged air leak and mean duration of drainage were also significantly reduced after application of the sealant (4.5% and 2.8 +/- 1.9 days versus 31.8% and 5.9 +/- 2.9 days) (P = .03 and P < .001).

CONCLUSIONS

Autologous fibrin sealant for reinforcement of the staple lines after lung volume reduction surgery significantly reduces prolonged air leak and duration of chest tube drainage.