PubMed Health⌕ Search

Biomedical subjects

F Granier

Publications and source records attributed to F Granier.

At least 19 recordsLinked to original sources
PubMed2001

Functional characterization of the KNOLLE-interacting t-SNARE AtSNAP33 and its role in plant cytokinesis.

Cytokinesis requires membrane fusion during cleavage-furrow ingression in animals and cell plate formation in plants. In Arabidopsis, the Sec1 homologue KEULE (KEU) and the cytokinesis-specific syntaxin KNOLLE (KN) cooperate to promote vesicle fusion in the cell division plane. Here, we characterize AtSNAP33, an Arabidopsis homologue of the t-SNARE SNAP25, that was identified as a KN interactor in a yeast two-hybrid screen. AtSNAP33 is a ubiquitously expressed membrane-associated protein that accumulated at the plasma membrane and during cell division colocalized with KN at the forming cell plate. A T-DNA insertion in the AtSNAP33 gene caused loss of AtSNAP33 function, resulting in a lethal dwarf phenotype. atsnap33 plantlets gradually developed large necrotic lesions on cotyledons and rosette leaves, resembling pathogen-induced cellular responses, and eventually died before flowering. In addition, mutant seedlings displayed cytokinetic defects, and atsnap33 in combination with the cytokinesis mutant keu was embryo lethal. Analysis of the Arabidopsis genome revealed two further SNAP25-like proteins that also interacted with KN in the yeast two-hybrid assay. Our results suggest that AtSNAP33, the first SNAP25 homologue characterized in plants, is involved in diverse membrane fusion processes, including cell plate formation, and that AtSNAP33 function in cytokinesis may be replaced partially by other SNAP25 homologues.

Amino Acid Sequence↗
PubMed2001

Arabidopsis glucosidase I mutants reveal a critical role of N-glycan trimming in seed development.

Glycoproteins with asparagine-linked (N-linked) glycans occur in all eukaryotic cells. The function of their glycan moieties is one of the central problems in contemporary cell biology. N-glycosylation may modify physicochemical and biological protein properties such as conformation, degradation, intracellular sorting or secretion. We have isolated and characterized two allelic Arabidopsis mutants, gcs1-1 and gcs1-2, which produce abnormal shrunken seeds, blocked at the heart stage of development. The mutant seeds accumulate a low level of storage proteins, have no typical protein bodies, display abnormal cell enlargement and show occasional cell wall disruptions. The mutated gene has been cloned by T-DNA tagging. It codes for a protein homologous to animal and yeast alpha-glucosidase I, an enzyme that controls the first committed step for N-glycan trimming. Biochemical analyses have confirmed that trimming of the alpha1,2- linked glucosyl residue constitutive of the N-glycan precursor is blocked in this mutant. These results demonstrate the importance of N-glycan trimming for the accumulation of seed storage proteins, the formation of protein bodies, cell differentiation and embryo development.

Alleles↗
PubMed2001

An arabidopsis T-DNA mutant affected in Nrt2 genes is impaired in nitrate uptake.

Expression analyses of Nrt2 plant genes have shown a strict correlation with root nitrate influx mediated by the high-affinity transport system (HATS). The precise assignment of NRT2 protein function has not yet been possible due to the absence of heterologous expression studies as well as loss of function mutants in higher plants. Using a reverse genetic approach, we isolated an Arabidopsis thaliana knock-out mutant where the T-DNA insertion led to the complete deletion of the AtNrt2.1 gene together with the deletion of the 3' region of the AtNrt2.2 gene. This mutant is impaired in the HATS, without being modified in the low-affinity system. Moreover, the de-regulated expression of a Nicotiana plumbaginifolia Nrt2 gene restored the mutant nitrate influx to that of the wild-type. These results demonstrate that plant NRT2 proteins do have a role in HATS.

Anion Transport Proteins↗
PubMed2001

Disruption of the Arabidopsis RAD50 gene leads to plant sterility and MMS sensitivity.

The Rad50 protein is involved in the cellular response to DNA-double strand breaks (DSBs), including the detection of damage, activation of cell-cycle checkpoints, and DSB repair via recombination. It is essential for meiosis in yeast, is involved in telomere maintenance, and is essential for cellular viability in mice. Here we present the isolation, sequence and characterization of the Arabidopsis thaliana RAD50 homologue (AtRAD50) and an Arabidopsis mutant of this gene. A single copy of this gene is present in the Arabidopsis genome, located on chromosome II. Northern analysis shows a single 4.3 Kb mRNA species in all plant tissues tested, which is strongly enriched in flowers and other tissues with many dividing cells. The predicted protein presents strong conservation with the other known Rad50 homologues of the amino- and carboxy-terminal regions. Mutant plants present a sterility phenotype which co-segregates with the T-DNA insertion. Molecular analysis of the mutant plants shows that the sterility phenotype is present only in the plants homozygous for the T-DNA insertion. An in vitro mutant cell line, derived from the mutant plant, shows a clear hypersensitivity to the DNA-damaging agent methylmethane sulphonate, suggesting a role of RAD50 in double-strand break repair in plant cells. This is the first report of a plant mutated in a protein of the Rad50-Mre11-Xrs2 complex, as well as the first data suggesting the involvement of the Rad50 homologue protein in meiosis and DNA repair in plants.

Amino Acid Sequence↗
PubMed2001

A T-DNA insertion knockout of the bifunctional lysine-ketoglutarate reductase/saccharopine dehydrogenase gene elevates lysine levels in Arabidopsis seeds.

Plants possess both anabolic and catabolic pathways for the essential amino acid lysine (Lys). However, although the biosynthetic pathway was clearly shown to regulate Lys accumulation in plants, the functional significance of Lys catabolism has not been experimentally elucidated. To address this issue, we have isolated an Arabidopsis knockout mutant with a T-DNA inserted into exon 13 of the gene encoding Lys ketoglutarate reductase/saccharopine dehydrogenase. This bifunctional enzyme controls the first two steps of Lys catabolism. The phenotype of the LKR/SDH knockout was indistinguishable from wild-type plants under normal growth conditions, suggesting that Lys catabolism is not an essential pathway under standard growth conditions. However, mature seeds of the knockout mutant over-accumulated Lys compared with wild-type plants. This report provides the first direct evidence for the functional significance of Lys catabolism in regulating Lys accumulation in seeds. Such a knockout mutant may also provide new perspectives to improve the level of the essential amino acid Lys in plant seeds.

Arabidopsis↗
PubMed2001

[Management of erysipelas].

The objective of this literature review was to evaluate the therapeutic management of erysipelas. We selected 74 publications, some of written a long time ago, and thus open to criticism regarding their methodology. However, no recent or better study was available on the subject. Penicillin G remains the therapeutic reference. The use of macrolides and stretogramins is an alternative after the exclusion of severe forms of erysipelas. The preventive treatment of thrombosis by heparin must be discussed taking into account risk factors. More studies are necessary to suggest a coprescription corticoid/NSAIDs and antibiotherapy. The best antibiotic prophylaxis after the initial treatment isabenzathine-penicillin injection every 15 days.

Adrenal Cortex Hormones↗
PubMed2000

[Invasive fungal infections. Epidemiology and new therapies].

RISING INCIDENCE: In the past two decades, systemic fungal infections, essentially invasive candidiasis, but also invasive aspergillosis, has increased substantially. Despite the currently available antifungal drugs, amphotericin B (AmB), azole compounds (fluconazole or FLU, itraconazole or ITR), these infections are associated with significant morbidity and mortality. AmB remains the drug of choice for treatment of most fungal diseases because of its broad spectrum and potent fungicidal activity, but significant side effects limit its clinical utility. The azole antifungal agents are easier to take, less toxic than AmB, but their use is limited by multiazole-resistant strains. NEW ANTIFUNGAL AGENTS: Lipid formulations have recently attracted much attention due to a significantly lower toxicity: this concerns lipid formulations of AmB and perhaps nystatin in the future. New triazoles (voriconazole, ravuconazole, posaconazole) have shown a wide spectrum of action including against azole-resistant isolates. A new class of antifungal agents, lipopeptides (MK-0991, LY303366, FK463), with an original mechanism of action are being developed. These new compounds are reported to possess a large fungicidal activity against most isolates including AmB and azole-resistant strains.

Amphotericin B↗
PubMed2000

Plant lipoxygenase 2 is a translation initiation factor-4E-binding protein.

The eukaryotic initiation factor 4E (eIF4E) emerged recently as a target for different types of regulation affecting translation. In animal and yeast cells, eIF4E-binding proteins modulate the availability of eIF4E. A search for plant eIF4E-binding proteins from Arcabictopsis thaliana using the yeast genetic interaction system identified a clone encoding a lipoxygenase type 2 (AtLOX2). In vitro and in vivo biochemical assays confirm an interaction between AtLOX2 and plant eIF4E(iso) factor. A two-hybrid assay revealed that AtLOX2 is also able to interact with both wheat initiation factors 4E and 4E(iso). Deletion analysis maps the region of AtLOX2 involved in interaction with AteIF(iso)4E between amino acids 175 and 232. A sequence related to the conserved motif present in several eIF4E-binding proteins was found in this region. Furthermore, the wheat p86 subunit, a component of the plant translation eIF(iso)4F complex, was found to interfere with the AteIF(iso)4E-AtLOX2 interaction suggesting that p86 and AtLOX2 compete for the same site on eIF(iso)4E. These results may reflect a link between eIF4Es factors mediating translational control with LOX2 activity, which is probably conserved throughout the plant kingdom.

Amino Acid Sequence↗
PubMed1997

Synthesis of full-length potyvirus cDNA copies suitable for the analysis of genome polymorphism.

New methods facilitating the synthesis and amplification of full-length cDNA copies of single-stranded viral RNA genomes have been developed. A method is described for the efficient purification of potyviral RNA and total RNA from infected plants and it is shown that they can serve as templates for the efficient synthesis of a full-length, 10 kb long, genomic cDNA. Two different reverse transcriptases were used (AMV-RT and MMLV-RT); only the first reverse transcriptase produced a good quality, full-length cDNA using viral RNA as a template. Surprisingly, MMLV-RT allowed for the full-length cDNA synthesis on virions rather than viral RNA. The PVY cDNA, synthesized using either RNA or virions, can be amplified successfully by PCR with high yields of full-length products. Such products are good substrates for the study by RFLP of the total genome polymorphism of virus isolates.

DNA, Complementary↗
PubMed1994

[Nocardia farcinica infection. Cutaneous form in an immunodepressed patient].

Nocardiosis is a rare localized or systemic infection caused by bacteria of the Actinomycetaceae family. Nocardia farcinica, recently identified as a distinct species from Nocardia asteroides, characteristically causes severe systemic infections and is particularly resistant to antibiotics. We report a case of nocardiosis observed in a patient receiving general corticosteroid therapy for bullous pemphigoid and who developed a sub-cutaneous abscess of the breast. N. farcinica was identified on puncture specimens and found to be resistant to beta-lactams, aminosides, cyclines, chloramphenicol, fosfomycin and pefloxacin. No dissemination beyond the skin was observed. The abscess was drained and cleaned surgically and cicatrization was uneventful. Six weeks later the patient was again hospitalized for an inflammatory abscess of the left buttocks which was drained surgically. N. farcinica was again identified and a complete work-up eliminated dissemination. Cotrimoxazole was given as a long-term therapy (480 mg trimethoprim, 2.4g sulfamethoxazole) for 6 months and was well tolerated. No recurrence was observed.

Abscess↗
PubMed1993

Granulomatous cheilitis in two children with sarcoidosis.

Sarcoidosis is rare in children, who usually have only asymptomatic pulmonary involvement. We report granulomatous cheilitis in two children with sarcoidosis. Both children had systemic sarcoidosis with lymph node and pulmonary involvement.

Child↗
PubMed1993

Mutations in zucchini yellow mosaic virus helper component protein associated with loss of aphid transmissibility.

Zucchini yellow mosaic virus (ZYMV) is a potyvirus transmitted by aphids in a non-persistent manner. Isolates having partially or totally lost their ability to be transmitted by aphids have been isolated and found to be affected in their helper component activities. We have sequenced the helper component coding region of poorly aphid-transmissible (PAT) variants of two strains of ZYMV, E15 and R5A. Mutations have been identified at the nucleotide level leading to two amino acid changes in the E15 PAT variant helper component and to one amino acid change located in the cysteine-rich region (well-conserved among potyviruses) in R5A PAT variant helper component. The mutation in the R5A variant changes the same amino acid as the one identified in potato virus C, a non-transmissible strain of potato virus Y.

Amino Acid Sequence↗
PubMed1992

[The work of collecting materials of artistic expression from various media].

Work of collection of productions made in workshops of expression constitute a specific need for evaluation in art-therapy. The Mediatised Observation is completed by special validated (K-test) and built instruments of description for productions from each mediation (paintings, writings, music...) and for observed behaviours in situ during therapeutic work of creation. The two benefits are for nurses education, and for elaboration of a clinic of aesthetic.

Art Therapy↗
PubMed1992

[Nursing problems in intensive care for psychiatric patients].

Two cases illustrate psychotherapeutic aspects of surgical intensive cares for psychiatric patients. Comparison with their style of expression in art-therapy allows a better understanding in their relations with the technical and non human environment.

Adaptation, Psychological↗