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P Oger

Publications and source records attributed to P Oger.

At least 19 recordsLinked to original sources
PubMed2006

In situ monitoring by quantitative Raman spectroscopy of alcoholic fermentation by Saccharomyces cerevisiae under high pressure.

We monitored alcoholic fermentation in Saccharomyces cerevisiae as a function of high hydrostatic pressure. Ethanol production from 0.15 M glucose was measured by Raman spectroscopy in situ in a diamond-anvil cell. At 10 MPa, fermentation proceeds three times faster than at ambient pressure and the fermentation yield is enhanced by 5% after 24 h. Above 20 MPa, the reaction kinetics slows down with increasing pressure. The pressure above which no more ethanol is produced is calculated to be 87 +/- 7 MPa. These results indicate that the activity of one or several enzymes of the glycolytic pathway is enhanced at low pressure up to 10 MPa. At higher pressures, they become progressively repressed, and they are completely inhibited above 87 MPa. Although fermentation was predicted to stop at ca. 50 MPa, due to the loss of activity of phosphofructokinase, the present study demonstrates that there is still an activity of ca. 30% of that measured at ambient pressure at 65 MPa. This study also validates the use of Raman spectroscopy for monitoring the metabolism of living microorganisms.

Ethanol↗
PubMed2006

[Pheochromocytoma and pregnancy. Case report].

The management of a pheochromocytoma during pregnancy is uncommon and is at high risk for both mother and foetus. We report a case of a patient whose first pregnancy was complicated by foetal demise in a context suggestive of preeclampsia. She was diagnosed with pheochromocytoma as she was beginning a second pregnancy. A laparoscopic adrenalectomy was performed in the first trimester of pregnancy, and maternal and neonatal outcome were favourable. This case illustrates the difficulty of diagnosing pheochromocytoma in pregnancy, and the benefits of laparoscopic treatment in the first trimester.

Adrenal Gland Neoplasms↗
PubMed2004

A highly selectable and highly transferable Ti plasmid to study conjugal host range and Ti plasmid dissemination in complex ecosystems.

A conjugal donor system, ST2, was constructed to study the conjugal dissemination of a Ti plasmid to wild-type recipient bacteria in vitro and in situ. The system consisted of a polyauxotrophic derivative of C58 harboring a hyperconjugative and highly selectable Ti plasmid, pSTiEGK, which was constructed by inserting a multiple antibiotic resistance cassette in the traM- mcpA region of pTiC58Delta accR. ST2 transfers pSTiEGK constitutively at frequencies up to 10(-1) to plasmidless Agrobacterium recipients. The host range of pSTiEGK includes all the known genomic species of Agrobacterium, indigenous soil agrobacteria and some Rhizobium and Phyllobacterium spp. All transconjugants became pathogenic upon acquisition of the Ti plasmid and were also able to transfer pSTiEGK by conjugation. This host range was indistinguishable from that of its wild-type parent pTiC58, and therefore pSTiEGK constitute a valid proxy to study the dissemination of Ti plasmids directly in the environment. Transconjugants can be selected on a combination of four antibiotics, which efficiently prevents the growth of the indigenous microbiota present in complex environments. The transfer of pSTiEGK to members of the genus Agrobacterium was affected primarily by the plasmid content of the recipient strain (10(3)- to 10(5)-fold reduction), e.g., the presence of incompatible plasmids. As a consequence, a species should be considered permissive to Ti transfer whenever one permissive isolate is found.

Chromosome Mapping↗
PubMed2002

[Care and management of cleft lip and palate by CLP Department hospital Robert Debre in Paris].

Cleft lip and palate repair must take a place at an early stage and respect physiology. Iatrogenic consequences harming maxillary growth must be avoided. Owing to early and reverse timing, short and long term results have been improved. Correction of the soft palate is performed at 3 months of age, lip and hard palate at 6 months without elevation of mucoperiosteum. A palatal plate is applied before and after each surgical stage. Patients receive phonetic, dental end ENT follow-up on a regular basis till end of growth. Correction of sequelae, especially of nasal tip, can be undertaken around grade school entrance at about 6 years of age. Nasal sequelae such as deviation of the septum must not be corrected before end of puberty. Surgery and follow-up must be conducted by an experienced multi-disciplinary team in which the surgeon plays the part of master of works.

Cleft Lip↗
PubMed2001

Co-evolution of the agrocinopine opines and the agrocinopine-mediated control of TraR, the quorum-sensing activator of the Ti plasmid conjugation system.

Conjugal transfer of Agrobacterium tumefaciens Ti plasmids is controlled by a hierarchical system in which opines, substrates produced by crown gall tumours, induce a quorum-sensing system. The cascade results from the control of expression of traR, the quorum-sensing activator, by a regulator responsive to the opine. In the two cases studied to date, the gene arrangements responsible for the cascade differ remarkably, suggesting that considerable diversity exists among the many Ti-like plasmids in the agrobacteria. In this study, we demonstrated that the novel Ti plasmid pTiChry5 is induced to transfer at high frequency by extracts from tumours initiated by strain Chry5. The purified inducer had the chemical and biological properties of agrocinopines C and D, a set of sugar phosphodiester opines known to induce transfer of another Ti plasmid, pTiBo542. The T-region of pTiChry5 contained a gene whose product, called Acs(Chry5), is virtually identical to the agrocinopine C+D synthase from the T-region of pTiBo542. The two genes are less closely related to acs of pTiC58, which is responsible for the production of agrocinopines A+B, a similar but not identical set of phosphodiester opines by tumours induced by strain C58. Agrocinopines A+B induce transfer of pTiC58 but did not induce transfer of pTi(Chry5). A single copy of traR was identified at the 11 o'clock region of pTi(Chry5), where it is part of a two-gene operon called arc(Chry5). Although altered by deletions, arc(Chry5) is related to the five-gene arc operon that controls the expression of traR on pTiC58. Expression of traR(Chry5) was induced by agrocinopines C+D and the opines isolated from Chry5 tumours but not by agrocinopines A+B. A mutation in traR(Chry5) abolished transfer, and transfer was restored by complementation in trans. We conclude that the agrocinopine opines and the corresponding opine-meditated conjugal regulatory regions of pTiChry5 and pTiC58 share a common origin, but that the opine signals for the two Ti plasmids have evolved divergently through changes in the opine synthase enzymes. The alterations in the opines, in turn, necessitated a co-evolutionary change in the opine recognition systems responsible for controlling expression of the traR genes on these two types of Ti plasmids.

Agrobacterium tumefaciens↗
PubMed2001

Iron-binding compounds from Agrobacterium spp.: biological control strain Agrobacterium rhizogenes K84 produces a hydroxamate siderophore.

Iron-binding compounds were produced in various amounts in response to iron starvation by a collection of Agrobacterium strains belonging to the species A. tumefaciens, A. rhizogenes, and A. vitis. The crown gall biocontrol agent A. rhizogenes strain K84 produced a hydroxamate iron chelator in large amounts. Production of this compound, and also of a previously described antibiotic-like substance called ALS84, occurred only in cultures of strain K84 grown in iron-deficient medium. Similarly, sensitivity to ALS84 was expressed only when susceptible cells were tested in low-iron media. Five independent Tn5-induced mutants of strain K84 affected in the production of the hydroxamate iron chelator showed a similar reduction in the production of ALS84. One of these mutants, M8-10, was completely deficient in the production of both agents and grew poorly compared to the wild type under iron-limiting conditions. Thus, the hydroxamate compound has siderophore activity. A 9.1-kb fragment of chromosomal DNA containing the Tn5 insertion from this mutant was cloned and marker exchanged into wild-type strain K84. The homogenote lost the ability to produce the hydroxamate siderophore and also ALS84. A cosmid clone was isolated from a genomic library of strain K84 that restored to strain M8-10 the ability to produce of the siderophore and ALS84, as well as growth in iron-deficient medium. This cosmid clone contained the region in which Tn5 was located in the mutant. Sequence analysis showed that the Tn5 insert in this mutant was located in an open reading frame coding for a protein that has similarity to those of the gramicidin S synthetase repeat superfamily. Some such proteins are required for synthesis of hydroxamate siderophores by other bacteria. Southern analysis revealed that the biosynthetic gene from strain K84 is present only in isolates of A. rhizogenes that produce hydroxamate-type compounds under low-iron conditions. Based on physiological and genetic analyses showing a correlation between production of a hydroxamate siderophore and ALS84 by strain K84, we conclude that the two activities share a biosynthetic route and may be the same compound.

Amino Acid Sequence↗
PubMed2000

Effect of crop rotation and soil cover on alteration of the soil microflora generated by the culture of transgenic plants producing opines.

The culture of transgenic Lotus corniculatus plants producing opines, which are bacterial growth substrates, leads to the selection of rhizospheric bacteria able to utilize these substrates. We have investigated the fate of the opine-utilizing community over time under different experimental conditions following elimination of selective pressure exerted by the transgenic plants. These plants were removed from the soil, which was either left unplanted or replanted with wild-type L. corniculatus or wheat plants. The density of opine-utilizing bacteria in the fallow soils remained essentially unchanged throughout the experiment, regardless of the soil of origin (soil planted with wild-type or transgenic plants). When wild-type Lotus plants were used to replace their transgenic counterparts, only the bacterial populations able to utilize the opines were affected. Long-term changes affecting the opine-utilizing bacterial community on Lotus roots was dependent upon the opine studied. The concentration of nopaline utilizers decreased, upon replacement of the transgenic plants, to a level similar to that of normal plants, while the concentration of mannopine utilizers decreased to levels intermediate between transgenic and normal plants. These data indicate that: (i) the opine-utilizing bacterial populations can be controlled in the rhizosphere via plant-exudate engineering; (ii) the interaction between the engineered plants and their root-associated micro-organisms is transgene specific; and (iii) alterations induced by the cultivation of transgenic plants may sometimes be persistent. Furthermore, opine-utilizing bacterial populations can be controlled by crop rotation. Therefore, favouring the growth of a rhizobacterium of agronomic interest via an opine-based strategy appears feasible.

Arginine↗
PubMed2000

A second T-region of the soybean-supervirulent chrysopine-type Ti plasmid pTiChry5, and construction of a fully disarmed vir helper plasmid.

Agrobacterium tumefaciens Chry5, which is particularly virulent on soybeans, induces tumors that produce a family of Amadori-type opines that includes deoxyfructosyl glutamine (Dfg) and its lactone, chrysopine (Chy). Cosmid clones mapping to the right of the known oncogenic T-region of pTiChry5 conferred Amadori opine production on tumors induced by the nopaline strain C58. Sequence analysis of DNA held in common among these cosmids identified two 25-bp, direct repeats flanking an 8.5-kb segment of pTiChry5. These probable border sequences are closely related to those of other known T-regions and define a second T-region of pTiChry5, called T-right (TR), that confers production of the Amadoriopines. The oncogenic T-left region (TL) was located precisely by identifying and sequencing the likely border repeats defining this segment. The two T-regions are separated by approximately 15 kb of plasmid DNA. Based on these results, we predicted that pKYRT1, a vir helper plasmid derived from pTiChry5, still contains all of TR and the leftmost 9 kb of TL. Consistent with this hypothesis, transgenic Arabidopsis thaliana plants selected for with a marker encoded by a binary plasmid following transformation with KYRT1 co-inherited production of the Amadori opines at high frequency. All opine-positive transgenic plants also contained TR-DNA, while those plants that lacked TR-DNA failed to produce the opines. Moreover, A. thaliana infected with KYRT1 in which an nptII gene driven by the 35S promoter of Cauliflower mosaic virus was inserted directly into the vir helper plasmid yielded kanamycin-resistant transformants at a low but detectable frequency. These results demonstrate that pKYRT1 is not disarmed, and can transfer Ti plasmid DNA to plants. A new vir helper plasmid was constructed from pTiChry5 by two rounds of sacB-mediated selection for deletion events. This plasmid, called pKPSF2, lacks both of the known T-regions and their borders. pKPSF2 failed to transfer Ti plasmid DNA to plants, but mobilized the T-region of a binary plasmid at an efficiency indistinguishable from those of pKYRT1 and the nopaline-type vir helper plasmid pMP90.

Agrobacterium tumefaciens↗
PubMed1998

[Bulky superinfected tinea capitis of the scalp. Treatment by surgical resection and reconstruction by cutaneous expansion].

BACKGROUND: Tinea capitis are usually cured by medical treatment. We present an unusual case which required a surgical treatment. CASE REPORT: A bulky infected kerion ignored for several weeks extended to a large part of the scalp of a 4-year-old girl. Antibiotics and antifungal agents were ineffective so that a total resection was necessary. The loss of substance was covered by a cutaneous graft; the large alopecia was secondarily repaired by a cutaneous expansion. Evolution has been followed for the past 10 years. CONCLUSION: It is exceptional that surgical treatment should be required for this condition.

Alopecia↗
PubMed1998

Octopine-type Ti plasmids code for a mannopine-inducible dominant-negative allele of traR, the quorum-sensing activator that regulates Ti plasmid conjugal transfer.

Conjugal transfer of Agrobacterium tumefaciens Ti plasmids is regulated by two hierarchical signalling systems. Transfer is dependent on a subset of opines produced by the plant tumours induced by the bacterium. Induction also requires an acyl-homoserine lactone signal, called AAI, that is produced by the bacteria themselves. AAI is the co-inducer for TraR, the transcriptional activator required for expression of the tra regulon. Octopine induces conjugation of the octopine-mannityl opine-type Ti plasmids by regulating the expression of traR via OccR, the octopine-dependent activator of the opine regulon. We have discovered a second traR-like gene, trlR, on the octopine-mannityl opine-type Ti plasmids pTi15955 and pTiR10. This gene is located in an operon coding for a mannopine transport system and is expressed as part of the mannityl opine regulon. Sequence analysis indicated that trlR is a frameshift allele of traR, and the resulting protein lacks the carboxy-terminal domain thought to constitute the DNA-binding region of TraR. Expression of trlR inhibited octopine-induced conjugation of pTi15955 and pTiR10 by suppressing the TraR-mediated transcription of the tra and trb operons. Although TrlR had no effect on the expression of traR, TraR activated the expression of trlR. Southern hybridizations indicated that several other Ti and opine-catabolic plasmids contain more than one copy of genes homologous to traR. We propose that trlR is a dominant negative allele of traR and that TrlR inhibits conjugation by forming inactive heteromultimers with TraR.

Agrobacterium tumefaciens↗
PubMed1998

[Fracture of the great trochanter treated by dynamic hip screw plate: measure of impaction according to fracture type].

INTRODUCTION: The sliding plate has appeared to be a reliable answer for trochanteric fractures. However, impaction allowed by the material may, have an adverse effect (medialisation, shortening, jutting out of the lag screw). The aim of our study was to measure the sliding of the screw in order to assess the impaction in various types of fracture, according to the Ender classification. MATERIAL AND METHODS: Hundred trochanteric fractures have been treated between 1991 and 1993. Eighty four have been analyzed with a follow-up of three months after surgery. The average age was 80.1 years with a 4.2 sex ratio (16 males). One hundred and thirty five degrees free sliding plates were employed for fracture fixation. Full weight bearing was allowed in 78.6 per cent of patients. According to Ender classification, 35 per cent of fractures were type 1, 4 or 5. This was the first group. The second group consisted of types 2 and 3 and the third group of types 6, 7 and 8. The results were assessed on AP and lateral X-rays. The ratio between screw thread length (constant) and screw outside the barrel length, was used to measure impaction on AP view. Osteoporosis was evaluated according to Singh. RESULTS: Despite two screw protrusions out of the femoral head and two failures of the plate, we have observed a healing rate of 100 per cent after three months. Sliding averaged 6.2 mm in group 1, 10.5 mm in group 2 and 16.4 mm in groupe 3. Weight bearing had a low influence on the amount of sliding. DISCUSSION: Group 1 consists of fractures (types 1, 4 and 5) which are two parts fractures considered as stable. Group 2 corresponds to types 2 and 3 considered as intermediate fractures with relative stability. In group 3 (types 6, 7 and 8) we have observed major fracture instability. Osteoporosis does not seem to be the major factor regarding screw sliding. CONCLUSION: The sliding plate is reliable. However, complex fractures healed in a wrong position which is definitely not acceptable, especially for young patients. Therefore, we advise to avoid the use of sliding plate in case of Ender type 6, 7 and 8.

Adult↗
PubMed1997

Genetically engineered plants producing opines alter their biological environment.

Little is known about the consequences of releasing genetically engineered plants (GEP) into the environment. Using opine-producing GEP, we show that transgenic plants alter their biological environment, more precisely the root-associated bacterial populations. The alterations were both transgene-specific and target population-specific. Therefore, assessment studies on the introduction of a given transgene into a GEP will be valid on the given transgene. Evidence of any transgene-associated biological effect will depend on the determination of the pertinent target populations, the identification of which is a key step of such studies.

Bacteria↗
PubMed1995

The use of digoxigenin-labelled probes to detect DNA sequences specific for plant pathogenic bacteria.

Southern blot hybridization is a valuable method in the assessment of the pathogenicity of bacterial strains or isolates. It is also a powerful tool for the demonstration of the presence of foreign DNA sequences in the genome of genetically-engineered plant cells. In this respect, cold, digoxigenin-labelled DNA probes can be used in place of classical radioactive probes, whether hybridizations are performed on bacterial genomic or plasmidic DNA, or on plant genomic DNA. The versatility of this cold labelling makes it suitable for the detection of unique bacterial genomic or plasmid sequences, even though these are located on large plasmids. The sensitivity of this cold probe technique also permits the detection of subpicogram quantities of DNA in plant genomic preparations. Their long term storage stability allows them to be frequently re-used over long periods of time, making this technique quite cost efficient.

Bacteria↗
PubMed1994

[Deformities of the fingers secondary to fingersucking].

After prolonged finger-sucking in early infancy, skeletal digital deformities, especially of the index finger, may occur. Thumb-sucking causes primarily dental disturbances whereas prolonged index--sucking may deform this finger, with functional as well as aesthetic consequences on the grip. Acquired rotation of the index finger is the most frequent deformity and does not always resolve spontaneously so that a rotation osteotomy had to be performed in 3 cases.

Finger Joint↗
PubMed1978

[Xeroderma pigmentosum. Therapeutic indications on the basis of 3 cases seen recently (author's transl)].

This condition is a genodermatosis, seen chiefly around the shores of the Mediterranean, characterised by early pigment disturbances which progress virtually inexorably towards a diffuse epitheliomatosis which usually results in death before the age of 20 years. Progression of the lesions is precipitated by exposure to UV rays. These lesions are seen essentially in exposed areas, in particular oculopalpebral. Treatment is first preventive (decrease in exposure to sun and protection). Otherwise, surgery remains the most effective method: either excision as required, or extensive cervicofacial prophylactic excision followed by grafting.

Adult↗