We tested the hypothesis that skeletal muscle ubiquitin-proteasome-dependent proteolysis is dysre... more We tested the hypothesis that skeletal muscle ubiquitin-proteasome-dependent proteolysis is dysregulated in ageing in response to feeding. In Experiment 1 we measured rates of proteasome-dependent proteolysis in incubated muscles from 8-and 22-month-old rats, proteasome activities, and rates of ubiquitination, in the postprandial and postabsorptive states. Peptidase activities of the proteasome decreased in the postabsorptive state in 22-month-old rats compared with 8-month-old animals, while the rate of ubiquitination was not altered. Furthermore, the down-regulation of in vitro proteasome-dependent proteolysis that prevailed in the postprandial state in 8-month-old rats was defective in 22-month-old rats. Next, we tested the hypothesis that the ingestion of a 5% leucine-supplemented diet may correct this defect. Leucine supplementation restored the postprandial inhibition of in vitro proteasome-dependent proteolysis in 22-month-old animals, by down-regulating both rates of ubiquitination and proteasome activities. In Experiment 2, we verified that dietary leucine supplementation had long-lasting effects by comparing 8-and 22-month-old rats that were fed either a leucine-supplemented diet or an alanine-supplemented diet for 10 days. The inhibited in vitro proteolysis was maintained in the postprandial state in the 22-month-old rats fed the leucine-supplemented diet. Moreover, elevated mRNA levels for ubiquitin, 14-kDa ubiquitin-conjugating enzyme E2, and C2 and X subunits of the 20S proteasome that were characteristic of aged muscle were totally suppressed in 22-month-old animals chronically fed the leucine-supplemented diet, demonstrating an in vivo effect. Thus the defective postprandial down-regulation of in vitro proteasome-dependent proteolysis in 22-month-old rats was restored in animals chronically fed a leucine-supplemented diet.
Journal of Neurology, Neurosurgery & Psychiatry, 2012
Although visual hallucinations in Parkinson&a... more Although visual hallucinations in Parkinson's disease (PD) have been described in several major studies, little is known about olfactory hallucinations (OHs). The authors performed a detailed analysis of OHs in a cohort of 87 Parkinsonian patients to estimate the prevalence of OHs and describe their phenomenology. They also evaluated smelling abilities in terms of detection and identification. Assessment of both, OHs and olfactory function, was also performed using a control group of 40 normal subjects. Nine patients exhibited OHs compared with none of the controls, giving a prevalence of 10% for OHs in patients. OHs were described as rare, short-lasting, unpleasant odours which are not frightening since clearly identified by the patient as hallucinations. Parkinsonian patients with OHs exhibited olfactory impairment of detection and identification compared with controls, but there was no difference in their olfactory abilities from Parkinsonian patients without OHs. In conclusion, OHs should be added to the list of non-motor PD symptoms that can occur early or late in the course of PD. The authors' study did not reveal any significant difference in terms of olfactory abilities between patients with or without OHs. However, olfactory impairment is well documented in Parkinsonian patients and cannot be totally ruled out as a risk factor for OHs. The authors recognise that complex mechanisms are probably involved in this phenomenon.
Phytophthora infestans, the causal agent of late blight, remains the main threat to potato produc... more Phytophthora infestans, the causal agent of late blight, remains the main threat to potato production worldwide. Screening of 19 accessions of Solanum dulcamara with P. infestans isolate Ipo82001 in detached leaf assays revealed strong resistance in an individual belonging to accession A54750069-1. This plant was crossed with a susceptible genotype, and an F(1) population consisting of 63 individuals was obtained. This population segregated for resistance in 1:1 ratio, both in detached leaf assays and in an open-field experiment. Presence of the formerly mapped Rpi-dlc1 gene as the cause of the observed segregating resistance could be excluded. Subsequently, AFLP analyses using 128 primer combinations enabled identification of five markers linked to a novel resistance gene named Rpi-dlc2. AFLP markers did not show sequence similarity to the tomato and potato genomes, hampering comparative genetic positioning of the gene. For this reason we used next-generation mapping (NGM), an approach that exploits direct sequencing of DNA (in our case: cDNA) pools from bulked segregants to calculate the genetic distance between SNPs and the locus of interest. Plotting of these genetic distances on the tomato and potato genetic map and subsequent PCR-based marker analysis positioned the gene on chromosome 10, in a region overlapping with the Rpi-ber/ber1 and -ber2 loci from S. berthaultii. Pyramiding of Rpi-dlc2 and Rpi-dlc1 significantly increased resistance to P. infestans, compared with individuals containing only one of the genes, showing the usefulness of this strategy to enhance resistance against Phytophthora.
The Arabidopsis AINTEGUMENTA (ANT) protein is essential for proper ovule development, but functio... more The Arabidopsis AINTEGUMENTA (ANT) protein is essential for proper ovule development, but functions in cell proliferation and organ growth throughout the plant. Here we report the isolation of a full-length cDNA clone from tobacco (Nicotiana tabacum L.) that encodes a protein with high similarity to ANT and is preferentially expressed in the pistil. In situ hybridization analysis on the tobacco ovary shows that the expression pattern of the corresponding gene is different from that of ANT in Arabidopsis.
Ethylene and gibberellins (GAs) control similar developmental processes in plants. The role of et... more Ethylene and gibberellins (GAs) control similar developmental processes in plants. The role of ethylene is at least in part to regulate the accumulation of DELLA proteins, key regulators of plant growth, which suppress the GA response. To expand our knowledge of ethylene-GA crosstalk and to reveal how the modulation of the ethylene and GA pathways affects global plant growth, the gibberellin-insensitive (gai), ethylene-overproducing 2-1 (eto2-1) double mutant, which has decreased GA signalling (resulting from gai) and increased ethylene biosynthesis (resulting from eto2-1), was characterized. Both single mutations resulted in reduced elongation growth. The double mutant showed synergistic responses in root and shoot growth, in induction of floral transition, and in inflorescence length, showing that crosstalk between the two pathways occurs in different plant organs throughout development. Furthermore, the altered ethylene-GA interactions affected root-shoot communication, as evidenced by an enhanced shoot:root ratio in the double mutant. When compared with both single mutants and the wild type, double mutants had enhanced content of active GA(4) at both the seedling and the rosette stages, and, unlike the gai mutant, they were sensitive to GA treatment. Finally, it was shown that synergistic responses in the double mutant were not caused by elevated ethylene biosynthesis but that, in the light, enhanced sensitivity to ethylene may, at least in part, be responsible for the observed phenotype.
Ethylene induces different sets of genes in different tissues and at different stages of developm... more Ethylene induces different sets of genes in different tissues and at different stages of development. To investigate whether these differential responses are caused by differential expression of members of the EIN3 family transcription factors, ®ve tobacco family members were isolated. They can be divided into three subgroups, which is probably due to the amphidiploid nature of tobacco. In phylogenetic analysis, each of the subgroups clustered with one of the three tomato EIL proteins and all NtEILs proved to be most homologous to Arabidopsis EIN3 and EIL1. Although organ-speci®c ethylene responses have been observed before, northern blot analysis showed that all NtEILs were expressed in all organs. To study differential NtEIL expression at the cellular level, in situ hybridization was used on the tobacco ovary. It was found that different ovary tissues displayed variable ethylene-induced expression of two ethyleneresponsive marker genes. By contrast, no differences were found in expression level or tissue-speci®city for any of the NtEILs in the ovary, before or after ethylene treatment. This indicates that the organ and tissue-speci®c ethylene responses are not caused by differential expression of NtEIL family members. These results support a model in which the developmental signals that regulate the tissue-speci®c responses are integrated with the ethylene signal downstream of a common primary ethylene-signalling pathway.
Many semi-aquatic plants respond to flooding by elongating the shoot to reach the water surface. ... more Many semi-aquatic plants respond to flooding by elongating the shoot to reach the water surface. This response is initiated by accumulation of ethylene in the plant due to decreased gas-exchange and continued ethylene production during submergence. Ethylene biosynthesis is often limited by the availability of 1aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, synthesized by ACC synthase. Here, is reported the cloning of a Rumex palustris cDNA corresponding to an ACC synthase gene (RP-ACS1), whose expression is induced by submergence in the long term but does not precede the observed short-term increase in ACS activity. Under aerated conditions, RP-ACS1 messenger accumulation exhibited circadian rhythmicity with high levels in the dark phase and low levels in the light phase, similar to the oscillations in ethylene production under these conditions. ACC oxidase (RP-ACO1) messenger accumulation also showed a rhythmic pattern, but opposite to that of RP-ACS1, and closely resembled the ethylene oscillation found in R. palustris plants that were waterlogged. Together the results indicate that transcriptional regulation of RP-ACS1 may directly control rhythmic ethylene production under aerated condition and suggest that post-transcriptional regulation is important in initial upregulation of ACS activity upon submergence.
Contraversive eye deviation (CED) is most often observed intraoperatively during subthalamic nucl... more Contraversive eye deviation (CED) is most often observed intraoperatively during subthalamic nucleus implantation for Parkinson's disease and considered to result from wrong electrode positioning. We report on a woman, bilaterally implanted in the subthalamic nucleus for severe Parkinson's disease disclosing long-lasting CED only when the stimulators were activated separately. Clinical examination and eye movements recording in this patient showed that CED occurred when stimulation was applied at the site and at similar intensity used for the best antiparkinsonian effect. These results suggest that the subthalamic area may be involved in orienting movements, either through the subthalamic nucleus itself or the fibers from the Frontal Eye Fields. Interestingly, this report shows that CED may be corrected by bilateral stimulation and that CED may not necessarily implicate electrode repositioning.
We tested the hypothesis that skeletal muscle ubiquitin-proteasome-dependent proteolysis is dysre... more We tested the hypothesis that skeletal muscle ubiquitin-proteasome-dependent proteolysis is dysregulated in ageing in response to feeding. In Experiment 1 we measured rates of proteasome-dependent proteolysis in incubated muscles from 8-and 22-month-old rats, proteasome activities, and rates of ubiquitination, in the postprandial and postabsorptive states. Peptidase activities of the proteasome decreased in the postabsorptive state in 22-month-old rats compared with 8-month-old animals, while the rate of ubiquitination was not altered. Furthermore, the down-regulation of in vitro proteasome-dependent proteolysis that prevailed in the postprandial state in 8-month-old rats was defective in 22-month-old rats. Next, we tested the hypothesis that the ingestion of a 5% leucine-supplemented diet may correct this defect. Leucine supplementation restored the postprandial inhibition of in vitro proteasome-dependent proteolysis in 22-month-old animals, by down-regulating both rates of ubiquitination and proteasome activities. In Experiment 2, we verified that dietary leucine supplementation had long-lasting effects by comparing 8-and 22-month-old rats that were fed either a leucine-supplemented diet or an alanine-supplemented diet for 10 days. The inhibited in vitro proteolysis was maintained in the postprandial state in the 22-month-old rats fed the leucine-supplemented diet. Moreover, elevated mRNA levels for ubiquitin, 14-kDa ubiquitin-conjugating enzyme E2, and C2 and X subunits of the 20S proteasome that were characteristic of aged muscle were totally suppressed in 22-month-old animals chronically fed the leucine-supplemented diet, demonstrating an in vivo effect. Thus the defective postprandial down-regulation of in vitro proteasome-dependent proteolysis in 22-month-old rats was restored in animals chronically fed a leucine-supplemented diet.
Journal of Neurology, Neurosurgery & Psychiatry, 2012
Although visual hallucinations in Parkinson&a... more Although visual hallucinations in Parkinson's disease (PD) have been described in several major studies, little is known about olfactory hallucinations (OHs). The authors performed a detailed analysis of OHs in a cohort of 87 Parkinsonian patients to estimate the prevalence of OHs and describe their phenomenology. They also evaluated smelling abilities in terms of detection and identification. Assessment of both, OHs and olfactory function, was also performed using a control group of 40 normal subjects. Nine patients exhibited OHs compared with none of the controls, giving a prevalence of 10% for OHs in patients. OHs were described as rare, short-lasting, unpleasant odours which are not frightening since clearly identified by the patient as hallucinations. Parkinsonian patients with OHs exhibited olfactory impairment of detection and identification compared with controls, but there was no difference in their olfactory abilities from Parkinsonian patients without OHs. In conclusion, OHs should be added to the list of non-motor PD symptoms that can occur early or late in the course of PD. The authors' study did not reveal any significant difference in terms of olfactory abilities between patients with or without OHs. However, olfactory impairment is well documented in Parkinsonian patients and cannot be totally ruled out as a risk factor for OHs. The authors recognise that complex mechanisms are probably involved in this phenomenon.
Phytophthora infestans, the causal agent of late blight, remains the main threat to potato produc... more Phytophthora infestans, the causal agent of late blight, remains the main threat to potato production worldwide. Screening of 19 accessions of Solanum dulcamara with P. infestans isolate Ipo82001 in detached leaf assays revealed strong resistance in an individual belonging to accession A54750069-1. This plant was crossed with a susceptible genotype, and an F(1) population consisting of 63 individuals was obtained. This population segregated for resistance in 1:1 ratio, both in detached leaf assays and in an open-field experiment. Presence of the formerly mapped Rpi-dlc1 gene as the cause of the observed segregating resistance could be excluded. Subsequently, AFLP analyses using 128 primer combinations enabled identification of five markers linked to a novel resistance gene named Rpi-dlc2. AFLP markers did not show sequence similarity to the tomato and potato genomes, hampering comparative genetic positioning of the gene. For this reason we used next-generation mapping (NGM), an approach that exploits direct sequencing of DNA (in our case: cDNA) pools from bulked segregants to calculate the genetic distance between SNPs and the locus of interest. Plotting of these genetic distances on the tomato and potato genetic map and subsequent PCR-based marker analysis positioned the gene on chromosome 10, in a region overlapping with the Rpi-ber/ber1 and -ber2 loci from S. berthaultii. Pyramiding of Rpi-dlc2 and Rpi-dlc1 significantly increased resistance to P. infestans, compared with individuals containing only one of the genes, showing the usefulness of this strategy to enhance resistance against Phytophthora.
The Arabidopsis AINTEGUMENTA (ANT) protein is essential for proper ovule development, but functio... more The Arabidopsis AINTEGUMENTA (ANT) protein is essential for proper ovule development, but functions in cell proliferation and organ growth throughout the plant. Here we report the isolation of a full-length cDNA clone from tobacco (Nicotiana tabacum L.) that encodes a protein with high similarity to ANT and is preferentially expressed in the pistil. In situ hybridization analysis on the tobacco ovary shows that the expression pattern of the corresponding gene is different from that of ANT in Arabidopsis.
Ethylene and gibberellins (GAs) control similar developmental processes in plants. The role of et... more Ethylene and gibberellins (GAs) control similar developmental processes in plants. The role of ethylene is at least in part to regulate the accumulation of DELLA proteins, key regulators of plant growth, which suppress the GA response. To expand our knowledge of ethylene-GA crosstalk and to reveal how the modulation of the ethylene and GA pathways affects global plant growth, the gibberellin-insensitive (gai), ethylene-overproducing 2-1 (eto2-1) double mutant, which has decreased GA signalling (resulting from gai) and increased ethylene biosynthesis (resulting from eto2-1), was characterized. Both single mutations resulted in reduced elongation growth. The double mutant showed synergistic responses in root and shoot growth, in induction of floral transition, and in inflorescence length, showing that crosstalk between the two pathways occurs in different plant organs throughout development. Furthermore, the altered ethylene-GA interactions affected root-shoot communication, as evidenced by an enhanced shoot:root ratio in the double mutant. When compared with both single mutants and the wild type, double mutants had enhanced content of active GA(4) at both the seedling and the rosette stages, and, unlike the gai mutant, they were sensitive to GA treatment. Finally, it was shown that synergistic responses in the double mutant were not caused by elevated ethylene biosynthesis but that, in the light, enhanced sensitivity to ethylene may, at least in part, be responsible for the observed phenotype.
Ethylene induces different sets of genes in different tissues and at different stages of developm... more Ethylene induces different sets of genes in different tissues and at different stages of development. To investigate whether these differential responses are caused by differential expression of members of the EIN3 family transcription factors, ®ve tobacco family members were isolated. They can be divided into three subgroups, which is probably due to the amphidiploid nature of tobacco. In phylogenetic analysis, each of the subgroups clustered with one of the three tomato EIL proteins and all NtEILs proved to be most homologous to Arabidopsis EIN3 and EIL1. Although organ-speci®c ethylene responses have been observed before, northern blot analysis showed that all NtEILs were expressed in all organs. To study differential NtEIL expression at the cellular level, in situ hybridization was used on the tobacco ovary. It was found that different ovary tissues displayed variable ethylene-induced expression of two ethyleneresponsive marker genes. By contrast, no differences were found in expression level or tissue-speci®city for any of the NtEILs in the ovary, before or after ethylene treatment. This indicates that the organ and tissue-speci®c ethylene responses are not caused by differential expression of NtEIL family members. These results support a model in which the developmental signals that regulate the tissue-speci®c responses are integrated with the ethylene signal downstream of a common primary ethylene-signalling pathway.
Many semi-aquatic plants respond to flooding by elongating the shoot to reach the water surface. ... more Many semi-aquatic plants respond to flooding by elongating the shoot to reach the water surface. This response is initiated by accumulation of ethylene in the plant due to decreased gas-exchange and continued ethylene production during submergence. Ethylene biosynthesis is often limited by the availability of 1aminocyclopropane-1-carboxylic acid (ACC), the precursor of ethylene, synthesized by ACC synthase. Here, is reported the cloning of a Rumex palustris cDNA corresponding to an ACC synthase gene (RP-ACS1), whose expression is induced by submergence in the long term but does not precede the observed short-term increase in ACS activity. Under aerated conditions, RP-ACS1 messenger accumulation exhibited circadian rhythmicity with high levels in the dark phase and low levels in the light phase, similar to the oscillations in ethylene production under these conditions. ACC oxidase (RP-ACO1) messenger accumulation also showed a rhythmic pattern, but opposite to that of RP-ACS1, and closely resembled the ethylene oscillation found in R. palustris plants that were waterlogged. Together the results indicate that transcriptional regulation of RP-ACS1 may directly control rhythmic ethylene production under aerated condition and suggest that post-transcriptional regulation is important in initial upregulation of ACS activity upon submergence.
Contraversive eye deviation (CED) is most often observed intraoperatively during subthalamic nucl... more Contraversive eye deviation (CED) is most often observed intraoperatively during subthalamic nucleus implantation for Parkinson's disease and considered to result from wrong electrode positioning. We report on a woman, bilaterally implanted in the subthalamic nucleus for severe Parkinson's disease disclosing long-lasting CED only when the stimulators were activated separately. Clinical examination and eye movements recording in this patient showed that CED occurred when stimulation was applied at the site and at similar intensity used for the best antiparkinsonian effect. These results suggest that the subthalamic area may be involved in orienting movements, either through the subthalamic nucleus itself or the fibers from the Frontal Eye Fields. Interestingly, this report shows that CED may be corrected by bilateral stimulation and that CED may not necessarily implicate electrode repositioning.
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