Research Interests:
Effects of appling exogenous jasmonic acid (JA) on the germination of Dioscorea alata L. microtubers were examined on Murashige and Skoog (MS) medium. Microtuber germination was promoted by JA (0.1 and 1 µM) supplemented to the culture... more
Effects of appling exogenous jasmonic acid (JA) on the germination of Dioscorea alata L. microtubers were examined on Murashige and Skoog (MS) medium. Microtuber germination was promoted by JA (0.1 and 1 µM) supplemented to the culture medium but higher concentrations (30 and 100 µM) completely inhibited germination. When these inhibited microtubers were transferred to hormone-free medium, germination resumed. After transfer to greenhouse conditions, almost all plants (95%) from tubers previously cultivated on MS medium with 100 µM JA survived and all acclimatized plants had produced tubers after 8 months. It is concluded that depending on JA concentration, both the germination and dormancy processes in D. alata microtubers were affected. The release from dormancy is easily obtained by transferring dormant microtubers to hormone-free medium.Peer reviewe
Research Interests:
peer reviewedaudience: researche
Research Interests:
The MIR396 family, composed of ath-miR396a and ath-miR396b in Arabidopsis, is conserved among plant species and is known to target the Growth-Regulating Factor (GRF) gene family. ath-miR396 overexpressors or grf mutants are characterised... more
The MIR396 family, composed of ath-miR396a and ath-miR396b in Arabidopsis, is conserved among plant species and is known to target the Growth-Regulating Factor (GRF) gene family. ath-miR396 overexpressors or grf mutants are characterised by small and narrow leaves and show embryogenic defects such as cotyledon fusion. Heterologous expression of ath-miR396a has been reported in tobacco and resulted in reduction of the expression of three NtGRF genes. In this study, the precursor of the Populus trichocarpa ptc-miR396c, with a mature sequence identical to ath-miR396b, was expressed under control of the CaMV35S promoter in tobacco. Typical phenotypes of GRF down-regulation were observed, including cotyledon fusion and lack of shoot apical meristem (SAM). At later stage of growth, transgenic plants had delayed development and altered specification of organ type during flower development. The third and fourth whorls of floral organs were modified into stigmatoid anthers and fasciated carpels, respectively. Several NtGRF genes containing a miR396 binding site were found to be down-regulated, and the cleavage of their corresponding mRNA at the miR396 binding site was confirmed for two of them using RACE-PCR analysis. The data obtained agree with the functional conservation of the miR396 family in plants and suggest a role for the miR396/GRF network in determination of floral organ specification.
Research Interests:
Plant UDP-glycosyltransferases (UGT) transfer sugars to small acceptor molecules and thereby play key roles in the biosynthesis of secondary metabolites, including phenylpropanoids. Some of those metabolites are involved in the xylem... more
Plant UDP-glycosyltransferases (UGT) transfer sugars to small acceptor molecules and thereby play key roles in the biosynthesis of secondary metabolites, including phenylpropanoids. Some of those metabolites are involved in the xylem lignification of a broad range of terrestrial plants, particularly trees. Here, we focused on poplar UGT72B37, coding for an enzyme glycosylating monolignols by investigating CRISPR/Cas9 mutant lines. The cell wall characterization revealed a 10% lignin content increase in the xylem of three-month-old mutant lines compared to the wild type. No ectopic lignification was evidenced in the pith of the stems of the mutants, suggesting that the increased lignin deposition is restricted to lignified cell walls. The analysis of the expression level of lignin biosynthesis and polymerization genes did not show significant changes between the WT and the ugt72b37 mutants, except for CINNAMOYL-COA REDUCTASE 2 which was significantly upregulated by 1.2–1.5-fold. Noti...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Polymorphism, Plant Biology, Biology, Medicine, Growth, and 15 morePopulus, Sequence alignment, Experimental Botany, STEM, Phloem, Gene, Transcription Factor, Gen, Cambium, Amino Acid Sequence, PLANT PROTEINS, Gene expression profiling, Secondary growth, Differential expression, and Molecular Sequence Data
Research Interests:
Research Interests: Plant Biology, Biology, Medicine, Gene expression, Populus, and 15 moreExperimental Botany, Flowers, Glucuronidase, Phenotype, Mitogen Activated Protein Kinase, Enzyme, Nicotiana Tabacum, Necrosis, Plant Pathogen, Plant Development, Physiological Stress Markers, Biological Assay, PLANT PROTEINS, Growth Retardation, and Plant Leaves
The application of immunoaffinity chromatography for the purification of Taxus plant and cell extracts prior to the HPLC analysis is described. Polyclonal antibodies raised against 10-deacetylbaccatin III (10-DAB III),... more
The application of immunoaffinity chromatography for the purification of Taxus plant and cell extracts prior to the HPLC analysis is described. Polyclonal antibodies raised against 10-deacetylbaccatin III (10-DAB III), paclitaxel's main precursor in plant, were characterised by enzymed-linked immunosorbent assay. Immunoglobulins from selected antisera were immobilised on CNBr-activated Sepharose 4B. The immunoaffinity column was used for the purification of plant and plant cell culture extracts prior to their analysis by HPLC. Immunoaffinity chromatography enabled the selective concentration of taxoids and enhanced sample clean-up.
Research Interests: Engineering, Chemistry, Chromatography, Medicine, Plant Cell Culture, and 15 moreAntibodies, Paclitaxel, Affinity chromatography, High Performance Liquid Chromatography, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Immunochemistry, Plant extracts, Taxus, Bovine Serum Albumin, Enzyme Linked Immunosorbent Assay, Immunoglobulin, Sepharose, immunoglobulin G, and Solvents
The gram-positive plant pathogen Rhodococcus fascians provokes leafy gall formation on a wide range of plants through secretion of signal molecules that interfere with the hormone balance of the host. Crucial virulence genes are located... more
The gram-positive plant pathogen Rhodococcus fascians provokes leafy gall formation on a wide range of plants through secretion of signal molecules that interfere with the hormone balance of the host. Crucial virulence genes are located on a linear plasmid, and their expression is tightly controlled. A mutant with a mutation in a chromosomal locus that affected virulence was isolated. The mutation was located in gene vicA , which encodes a malate synthase and is functional in the glyoxylate shunt of the Krebs cycle. VicA is required for efficient in planta growth in symptomatic, but not in normal, plant tissue, indicating that the metabolic requirement of the bacteria or the nutritional environment in plants or both change during the interaction. We propose that induced hyperplasia on plants represents specific niches for the causative organisms as a result of physiological alterations in the symptomatic tissue. Hence, such interaction could be referred to as metabolic habitat modif...
Research Interests:
The phytopathogen Rhodococcus fascians induces the development of leafy gall, which is considered to be its ecological niche. To obtain a view of the metabolic changes occurring in R. fascians during this process, an in vitro system was... more
The phytopathogen Rhodococcus fascians induces the development of leafy gall, which is considered to be its ecological niche. To obtain a view of the metabolic changes occurring in R. fascians during this process, an in vitro system was used where bacteria are grown in the presence of a leafy gall extract, a condition mimicking that found by the bacteria in infected plants. Proteins of R. fascians grown for 24 h under these conditions were displayed by two-dimensional polyacrylamide gel electrophoresis. Fifteen polypeptides showing a differential accumulation in response to the inducing conditions were analyzed by mass spectrometry. Two polypeptides potentially linked to the Krebs cycle, a pyruvate dehydrogenase and a fumarate hydratase, were further characterized and shown to be downregulated at the transcriptional level. The identification of these two enzymes suggests that R. fascians may shift its metabolism during the interaction with plants from the Krebs cycle to the glyoxylate shunt.
Research Interests: Microbiology, Mass Spectrometry, Medical Microbiology, Biology, Tobacco, and 13 moreEcological Niche Modeling, Medicine, Rhodococcus, Enzyme, Plant extracts, Current, Host Pathogen Interactions, Two-Dimensional Gel Electrophoresis, Polyacrylamide Gel Electrophoresis, Two dimensional Gel Electrophoresis, Proteome, Gene expression profiling, and Molecular Sequence Data
Quorum-sensing (QS) regulates the production of key virulence factors in Pseudomonas aeruginosa and other important pathogenic bacteria. In this report, extracts of leaves and bark of Combretum albiflorum (Tul.) Jongkind (Combretaceae)... more
Quorum-sensing (QS) regulates the production of key virulence factors in Pseudomonas aeruginosa and other important pathogenic bacteria. In this report, extracts of leaves and bark of Combretum albiflorum (Tul.) Jongkind (Combretaceae) were found to quench the production of QS-dependent factors in P. aeruginosa PAO1. Chromatographic fractionation of the crude active extract generated several active fractions containing flavonoids, as shown by their typical spectral features. Purification and structural characterization of one of the active compounds led to the identification of the flavan-3-ol catechin [(2R,3S)-2-(3,4-dihydroxyphenyl)-3,4-dihydro-1(2H)-benzopyran-3,5,7-triol]. The identity of catechin as one of the active molecules was confirmed by comparing the high-pressure liquid chromatography profiles and the mass spectrometry spectra obtained for a catechin standard and for the active C. albiflorum fraction. Moreover, standard catechin had a significant negative effect on pyoc...
Research Interests: Biofilms, Mass Spectrometry, Biology, Medicine, Multidisciplinary, and 14 moreApplied, Applied Environmental Microbiology, Quorum Sensing, Pseudomonas aeruginosa, High Pressure Liquid Chromatography, Anti-Bacterial Agents, Combretum, Virulence factor, Pseudomonas Aeruginosa, Virulence Factors, Catechin, Butyrolactone, Plant Leaves, and Down-Regulation
Research Interests:
Taxol and related taxane diterpenoids were isolated from pre-purified extracts of stem-barks of Taxus bacccata by HSCCC. The described method allowed to obtain a mixture of taxol and cephalomannine without any other interfering... more
Taxol and related taxane diterpenoids were isolated from pre-purified extracts of stem-barks of Taxus bacccata by HSCCC. The described method allowed to obtain a mixture of taxol and cephalomannine without any other interfering constituent and furthermore a partial separation of taxol (40 % of the total recovery) from cephalomannine. In addition, the HPLC and TLC separation conditions of these compounds
Research Interests:
General account concerning the distribution, importance, and biologically active constituents of Anthemis nobilis has been reported by Fauconnier et al. (1996). A. nobilis, the so-called Roman chamomile, is a perennial herb belonging to... more
General account concerning the distribution, importance, and biologically active constituents of Anthemis nobilis has been reported by Fauconnier et al. (1996). A. nobilis, the so-called Roman chamomile, is a perennial herb belonging to the Asteraceae family. It is native to southwest Europe and has spread all over Europe. It grows also in southwest Asia. The flower heads, the commercial drug, are used in traditional medicine for their pharmacological properties related to several groups of secondary metabolites: a sedative property has been attributed to the presence of esters (Melegari et al. 1988), antiinflammatory activity to flavonoids (Achterrath-Tuckermann et al. 1980; Della Loggia 1986), sesquiterpene lactones (Hall et al. 1979), and azulenes (Issac and Kristen 1980), antispasmodic activity to apiin and luteoside (Duke 1987), antibacterial activity to sesquiterpenic lactones and essential oil constituents (Rodriguez et al. 1979), and cytotoxicity to the presence of nobilin, and derivatives such as 1,10-epoxynobilin and 3-dehydronobilin (Leung 1980). Extracts from A. nobilis are also added to cosmetics, shampoos, and bath preparations, hair dye formulas, preparations for mouth washes, creams, and gels to treat cracked nipples (Proserpio et al. 1983; Rovesti et al. 1983).
Research Interests:
Research Interests:
... GUS quantification showed that the presence of the linear plasmid positively affected the absolute level of gene expression and that both plant and leafy gall extracts had a strong inducing ... 4. Hartig, A., Simon, MM, Schuster, T.,... more
... GUS quantification showed that the presence of the linear plasmid positively affected the absolute level of gene expression and that both plant and leafy gall extracts had a strong inducing ... 4. Hartig, A., Simon, MM, Schuster, T., Daugherty, JR, Yoo, HS, and Cooper, TG (1992). ...
Research Interests:
Research Interests:
... IN VITRO MULTIPLICATION OF CROCUS SATIVUS L. Authors: J. Homes, M. Legros, M. Jaziri. Abstract: Saffron is a product of high commercial value (up to $5000/kg) (Allan et al. 1985) and in vitro propagation of this plant can be useful. ...
Research Interests:
... GUS quantification showed that the presence of the linear plasmid positively affected the absolute level of gene expression and that both plant and leafy gall extracts had a strong inducing ... 4. Hartig, A., Simon, MM, Schuster, T.,... more
... GUS quantification showed that the presence of the linear plasmid positively affected the absolute level of gene expression and that both plant and leafy gall extracts had a strong inducing ... 4. Hartig, A., Simon, MM, Schuster, T., Daugherty, JR, Yoo, HS, and Cooper, TG (1992). ...
Research Interests:
The application of immunoaffinity chromatography for the purification of Taxus plant and cell extracts prior to the HPLC analysis is described. Polyclonal antibodies raised against 10-deacetylbaccatin III (10-DAB III), paclitaxel's... more
The application of immunoaffinity chromatography for the purification of Taxus plant and cell extracts prior to the HPLC analysis is described. Polyclonal antibodies raised against 10-deacetylbaccatin III (10-DAB III), paclitaxel's main precursor in plant, were characterised by enzymed-linked immunosorbent assay. Immunoglobulins from selected antisera were immobilised on CNBr-activated Sepharose 4B. The immunoaffinity column was used for the purification of plant and plant cell culture extracts prior to their analysis by HPLC. Immunoaffinity chromatography enabled the selective concentration of taxoids and enhanced sample clean-up.
Research Interests: Engineering, Chemistry, Technology, Medicine, Plant Cell Culture, and 15 moreAntibodies, Paclitaxel, Affinity chromatography, High Performance Liquid Chromatography, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Immunochemistry, Plant extracts, Taxus, Bovine Serum Albumin, Enzyme Linked Immunosorbent Assay, Immunoglobulin, Sepharose, immunoglobulin G, and Solvents
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
... 73 + 10 70+17 59+15 69 + 22 76 + 6 76 + 8 Les concentrations de GA3 que nous avons utilis?es se retrouvent dans la gamme des doses pr?conis?es pardiff?rents chercheurs (Saussay 1969, Chibbar et al. ... Ferreira J, Charles D, Simon J.... more
... 73 + 10 70+17 59+15 69 + 22 76 + 6 76 + 8 Les concentrations de GA3 que nous avons utilis?es se retrouvent dans la gamme des doses pr?conis?es pardiff?rents chercheurs (Saussay 1969, Chibbar et al. ... Ferreira J, Charles D, Simon J. & Janick J, 1992. ? ...
Inhibition of virulence gene expression in Rhodococcus fascians and Pseudomonas aeruginosa by flavonoïds isolated from the genera Dalbergia and Combretum. Inhibition de l’expression des gènes de virulence chez Rhodococcus fascians et Pseudomonas aeruginosa par des flavonoïdes isolés chez les genr...more
Research Interests:
Background/Aims: The Escherichia coli MazF is an endoribonuclease that cleaves mRNA at ACA sequences, thereby triggering inhibition of protein synthesis. The aim of this study is to evaluate the efficiency of the mazEF toxin-antitoxin... more
Background/Aims: The Escherichia coli MazF is an endoribonuclease that cleaves mRNA at ACA sequences, thereby triggering inhibition of protein synthesis. The aim of this study is to evaluate the efficiency of the mazEF toxin-antitoxin system in plants to develop biotechnological tools for targeted cell ablation. Methods: A double transformation strategy, combining expression of the mazE antitoxin gene under the control of the CaMV 35S promoter, reported to drive expression in all plant cells except within the tapetum, together with the expression of the mazF gene under the control of the TA29 tapetum-specific promoter in transgenic tobacco, was applied. Results: No transgenic TA29-mazF line could be regenerated, suggesting that the TA29 promoter is not strictly tapetum specific and that MazF is toxic for plant cells. The regenerated 35S-mazE/TA29-mazF double-transformed lines gave a unique phenotype where the tapetal cell layer was necrosed resulting in the absence of pollen. Conclu...
Research Interests:
Research Interests:
Research Interests:
Dalbergia trichocarpa, une source naturelle de composés bioactifs qui affectent le mécanisme de quorum sensing et la formation de biofilm chez Pseudomonas aeruginosa /Dalbergia trichocarpa, source of natural compounds which affect quorum sensing mechanism and biofilm formation in Pseudomonas aeru...more
Callus cultures of Taxus baccata L. cv. stricta were induced from hypocotyl and leaf explants on Woody Plant medium (hormone-free or additionated with phytohormones). Under continuous dark condition, adventitious roots were regenerated... more
Callus cultures of Taxus baccata L. cv. stricta were induced from hypocotyl and leaf explants on Woody Plant medium (hormone-free or additionated with phytohormones). Under continuous dark condition, adventitious roots were regenerated from hypocotyl- and leaf-derived callus cultures. Antibodies raised in rabbits against 10-succinyl-10-deacetylbaccatin III were used for the detection and the semi-quantitative determination of 10-deacetylbaccatin III in Taxus cultures. The presence of 10-deacetylbaccatin III in callus extracts was confirmed by TLC, HPLC using a photodiode array detector and mass spectrometry (CI-MS). The highest equivalent content of the taxoid derivatives (7.83 mg/100 g dry wt.) was detected in an extract from leaf-derived callus.
Research Interests:
A high-sensitive ELISA method was developed for the detection and semi-quantitative determination of 10-deacetylbaccatin III and its structurally related compounds in crude extract of Taxus sp. plants and tissue cultures. The antibodies... more
A high-sensitive ELISA method was developed for the detection and semi-quantitative determination of 10-deacetylbaccatin III and its structurally related compounds in crude extract of Taxus sp. plants and tissue cultures. The antibodies were raised in rabbits using 7- or 10-succinyl-10-deacetylbaccatin III-BSA conjugate as immunogen. The working range of the assay was from 0.003 to 1.000 ng (0.09 to 31.33 nM) of 10-deacetylbaccatin III per assay. The cross-reacting material in crude plant extract was examined by chromatographic (silica gel CC, HPLC) and immunoassay methods. Study on the evaluation of cross-reacting material in crude Taxus plant extracts showed that at least 80% of the immunosignal correspond to 10-deacetylbaccatin III in the extract. The ELISA method was applied to investigate the 10-deacetylbaccatin III equivalent content in crude extracts of 19 plants species including Taxaceae, Taxodiaceae and Pinaceae species. The 10-deacetylbaccatin III-like structure was only ...
Research Interests:
P. aeruginosais an opportunistic pathogenic bacterium responsible for both acute and chronic infections. Beyond its natural resistance to many drugs, its ability to form biofilm, a complex biological system, renders ineffective the... more
P. aeruginosais an opportunistic pathogenic bacterium responsible for both acute and chronic infections. Beyond its natural resistance to many drugs, its ability to form biofilm, a complex biological system, renders ineffective the clearance by immune defense systems and antibiotherapy. The objective of this report is to provide an overview (i) onP. aeruginosabiofilm lifestyle cycle, (ii) on the main key actors relevant in the regulation of biofilm formation byP. aeruginosaincluding QS systems,GacS/GacAandRetS/LadStwo-component systems and C-di-GMP-dependent polysaccharides biosynthesis, and (iii) finally on reported natural and synthetic products that interfere with control mechanisms of biofilm formation byP. aeruginosawithout affecting directly bacterial viability. Concluding remarks focus on perspectives to consider biofilm lifestyle as a target for eradication of resistant infections caused byP. aeruginosa.