Response of electrically stimulated cells of Pseudomonas oleovorans strain ATCC 29347 suspended in silicone oil.

A high intensity direct current was applied for more than 10 min onto a bacterial suspension of Pseudomonas oleovorans ATCC 29347 suspended in silicone oil. The application of a gradually increased electric field from 0 to 2500 V x cm(-1) resulted in a decrease of the optical density of the bacterial suspension and the occurrence of a peak current of several hundred microA for living cells instead of a linear increase (few microA) for killed or lyophilised cells. This procedure is not only a rapid way of investigating the living state of cell cultures but also an efficient experimental tool to study the cellular effects of a controlled electrical stress.

Physical, chemical, and microbiological characteristics of microbial mats (kopara) in the South Pacific atolls of French Polynesia.

Microbial mats that develop in shallow brackish and hyposaline ponds in the rims of two French polynesian atolls (Rangiroa and Tetiaroa) were intensively investigated during the past three years. Comparative assessment of these mats (called kopara in polynesian language) showed remarkable similarities in their composition and structure. Due to the lack of iron, the color of the cyanobacterial pigments produced remained visible through the entire depth of the mats (20-40 cm depth), with alternate green, purple, and pink layers. Profiles of oxygen, sulfide, pH, and redox showed the anoxia of all mats from a depth of 2-3 mm. Analyses of bacterial pigments and bacterial lipids showed that all mats consisted of stratified layers of cyanobacteria (mainly Phormidium, Schizothrix, Scytonema) and purple and green phototrophic bacteria. The purple and green phototrophic bacteria cohabit with sulfate reducers (Desulfovibrio and Desulfobacter) and other heterotrophic bacteria. The microscopic bacterial determination emphasized the influence of salinity on the bacterial diversity, with higher diversity at low salinity, mainly for purple nonsulfur bacteria. Analyses of organic material and of exopolymers were also undertaken. Difference and similarities between mats from geomorphological, microbiological, and chemical points of view are discussed to provide multicriteria of classification of mats.

Orenia salinaria sp. nov., a fermentative bacterium isolated from anaerobic sediments of Mediterranean salterns.

A diverse range of fermentative bacteria have been isolated from the commercial salterns of Salin-de-Giraud (Camargue, France). One of these isolates, strain SG 3902T, has many of the morphological and physiological characteristics of the genus Orenia, as was confirmed by a phylogenetic study based on 16S rRNA gene sequencing. The closest species is Orenia marismortui, with a similarity of only 95.1%. However, strain SG 3902T, unlike O. marismortui, does not ferment mannose, glycogen or starch. The G + C contents of the DNA also differ significantly, being 29.6 mol% for O. marismortui and 33.7 mol% for strain SG 3902T. On the basis of these physiological and genetic differences, it is proposed that strain SG 3902T should be considered as a representative of a new species belonging to the genus Orenia, under the name Orenia salinaria sp. nov. The type strain is SG 3902T (= ATCC 700911).

Haloanaerobacter salinarius sp. nov., a novel halophilic fermentative bacterium that reduces glycine-betaine to trimethylamine with hydrogen or serine as electron donors; emendation of the genus Haloanaerobacter.

A novel halophilic fermentative bacterium has been isolated from the black sediment below a gypsum crust and a microbial mat in hypersaline ponds of Mediterranean salterns. Morphologically, physiologically and genetically this organism belongs to the genus Haloanaerobacter. Haloanaerobacter strain SG 3903T (T = type strain) is composed of non-sporulating long flexible rods with peritrichous flagella, able to grow in the salinity range of 5-30% NaCl, with an optimum at 14-15%. The strain grows by fermenting carbohydrates or by using the Stickland reaction with either serine or H2 as electron donors and glycine-betaine as acceptor, which is reduced to trimethylamine. The two species described so far in the genus Haloanaerobacter are not capable of Stickland reaction with glycine-betaine + serine; however, Haloanaerobacter chitinovorans can use glycine-betaine with H2 as electron donor. Strain SG 3903T thus represents the first described strain in the genus Haloanaerobacter capable of the Stickland reaction with two amino acids. Although strain SG 3903T showed 67% DNA-DNA relatedness to H. chitinovorans, it is physiologically sufficiently different from the two described species to be considered as a new species which has been named Haloanaerobacter salinarius sp. nov.

Desulfotomaculum halophilum sp. nov., a halophilic sulfate-reducing bacterium isolated from oil production facilities.

A halophilic endospore-forming, sulfate-reducing bacterium was isolated from an oilfield brine in France. The strain, designated SEBR 3139, was composed of long, straight to curved rods. It grew in 1-14% NaCl with an optimum at 6%. On the basis of morphological, physiological and phylogenetical characteristics, strain SEBR 3139 should be classified in the genus Desulfotomaculum. However, it is sufficiently different from the hitherto described Desulfotomaculum species to be considered as a new species. Strain SEBR 3139T (= DSM 11559T) represents the first moderate halophilic species of the genus Desulfotomaculum. The name Desulfotomaculum halophilum sp. nov. is proposed.

Taxonomic rearrangements of the genera Thiocapsa and Amoebobacter on the basis of 16S rDNA sequence analyses, and description of Thiolamprovum gen. nov.

Complete nucleotide sequences of the 16S rDNAs were determined from Thiocapsa and Amoebobacter species, including all available type strains and some additional isolates. The distance-matrix analysis and the dendrogram for estimating the genetic relationships revealed that the investigated strains were found in two major clusters within the Chromatiaceae. One cluster comprises all Amoebobacter species, Thiocapsa roseopersicina and several isolates related to Thiocapsa roseopersicina. Representatives of the species Amoebobacter roseus, Amoebobacter pendens and Thiocapsa roseopersicina, the so called 'Thiocapsa roseopersicina group', are very closely related, justifying their inclusion into one genus, Thiocapsa, for which an emended description is presented. Amoebobacter purpureus and Amoebobacter pedioformis formed two separate lines of descent with less than 93% (89.6-92.9%) similarity to strains of the 'Thiocapsa roseopersicina group'. Therefore, they will be considered as two separate genera. As a consequence, an emended description is presented for the genus Amoebobacter, with Amoebobacter purpureus as the new type species and A. pedioformis is transferred to Thiolamprovum pedioforme gen. nov., comb. nov. Two species, Thiocapsa pfennigii and Thiocapsa halophila, which have been classified with the genus Thiocapsa because of their morphological properties, were found within another major cluster of the Chromatiaceae and are only distantly phylogenetically related to the first cluster with 88.4-90.6% and 90.4-92.2% sequence similarity, respectively.

Anaerobic Degradation of Hexadecan-2-one by a Microbial Enrichment Culture under Sulfate-Reducing Conditions.

A microbial enrichment culture from marine sediment was able to grow on hexadecan-2-one as the sole source of carbon and energy under sulfate-reducing conditions. Oxidation of the ketone involved carboxylation reactions and was coupled to sulfide production. This enrichment culture also grew on 6,10,14-trimethylpentadecan-2-one.

[Management of intracanalicular acoustic neurinoma]. / Conduite à tenir devant un neurinome de l'acoustique intracanalaire.

Between 1991 and 1996, 35 patients had an intracanalicular tumor: 26 patients were operated via middle cranial fossa approach (MFA: 23 cases) or translabyrinthine approach (TL: 3 cases), 9 cases were supervised by audiovestibular testing and MRI. For the operated patients through MFA the functional hearing (pure tone loss < 50 dB and 100% vocal discrimination) was preserved in 47.8% of cases, facial function was grade I and II in 83% of cases and grade III in 17% of cases. One recurrence was noted and reoperated by TL. For the TL operated patients, the postoperative facial function was normal (grade I) in all cases. Among the 9 supervised cases for reasons of age (more than 60 years), or the tumoral size (< than 5 mm): the tumor in 3 cases did not increase in size, 5 cases increased by 1 mm/year and 1 case increased 1 cm/year (and must be operated). These results show the importance of the middle cranial fossa approach for excision of intracanalicular neuromas and supervising patients with the same tumor according to age, and tumoral size.

Thiorhodococcus minus, gen. nov., sp. nov., A new purple sulfur bacterium isolated from coastal lagoon sediments.

A new marine phototrophic purple sulfur bacterium (strain CE2203) was isolated in pure culture from a man-made coastal lagoon located on the Atlantic coast (Arcachon Bay, France). Single cells were coccus-shaped, did not contain gas vesicles, and were highly motile. Intracellular photosynthetic membranes were of the vesicular type. Bacteriochlorophyll a and carotenoids of the normal spirilloxanthin series were present as photosynthetic pigments. Hydrogen sulfide, thiosulfate, elemental sulfur, and molecular hydrogen were used as electron donors during photolithotrophic growth under anoxic conditions, while carbon dioxide was utilized as carbon source. Acetate, propionate, lactate, glycolate, pyruvate, fumarate, succinate, fructose, sucrose, ethanol, and propanol were photoassimilated in the presence of hydrogen sulfide. During growth on sulfide, elemental sulfur globules were stored inside the cells. Chemotrophic growth under microoxic conditions in the dark was possible. The DNA base composition was 66.9 mol% G+C. Comparative sequence analysis of the 16S rRNA gene confirmed the membership of strain CE2203 in the family Chromatiaceae. Morphological characteristics of strain CE2203 indicated a close affiliation to the genera Thiocystis and Thiocapsa. However, the phylogenetic treeing revealed no closer relationship to Thiocystis spp. than to Thiocapsa roseopersicina or other known members of the Chromatiaceae. Consequently, strain CE2203 is proposed as the type strain of a new genus and species, Thiorhodococcus minus gen. nov., sp. nov.

[Trans-petrous surgery in acoustic neuroma. Value of preoperative audiovestibular and facial investigation in the risk evaluation of facial nerve function]. / Chirurgie transpétreuse du neurinome de l'acoustique. Intérêt des explorations audio-vestibulaires et faciales pré-opératoires dans l'évaluation du risque sur la fonction faciale.

Between 1987 and february 1994, 162 consecutive patients with acoustic neuroma were operated on by an otoneurosurgery team, using transpetrous approaches (89% translabyrinthine, 8% middle fossa and 3% retrosigmoid). The relationship between the clinical, audiometric and vestibulographic characteristics and the post-operative facial nerve function were evaluated. In acoustic neuromas with cerebello-pontine component inferior to 3 cm without central neurologic signs (ic: central controlateral auditory and/or ipsilateral vestibular pathway alteration), good post-operative facial nerve function was achieved in 80% of cases. In acoustic neuromas superior to 3 cm with alteration of the central vestibular and auditory pathways, a good result was obtained in only 30% of cases which correlated negatively with preoperative facial dysfunction. These results underline the value of preoperative facial and audiovestibular examinations in predicting the postoperative facial nerve function following surgery for acoustic neuroma.

Chromatium glycolicum sp. nov., a moderately halophilic purple sulfur bacterium that uses glycolate as substrate

From the microbial mats that develop in Solar Lake, a new purple sulfur bacterium was isolated. This strain (Chromatium strain SL 3201) was morphologically similar to Chromatium gracile and Chromatium minutissimum. Chromatium SL 3201 was found to be a moderate halophile with a growth range between 2 and 20% NaCl (optimum 4-5% NaCl) and was able to grow photo-organotrophically using glycolate and glycerol. It is the first described phototrophic sulfur bacterium able to use glycolate. According to NaCl requirements and utilization of organic compounds, the strain is not related to any known species of the genus Chromatium. On the basis of its 16S rRNA gene sequence, it clusters with other Chromatium species and is most similar to Chromatium salexigens and Chr. gracile, but it is sufficiently separated to be considered as a new species of the genus. It is, therefore, described as Chromatium glycolicum sp. nov.

Desulfovibrio gabonensis sp. nov., a new moderately halophilic sulfate-reducing bacterium isolated from an oil pipeline.

Two moderately halophilic sulfate-reducing bacteria were isolated from an African oil pipeline and designated strains SEBR 3640 and SEBR 2840T (T = type strain). Both of these strains possess traits that define the genus Desulfovibrio. The cells of both isolates were motile curved rods that had a single polar flagellum and contained desulfoviridin, and both isolates utilized lactate, pyruvate, malate, fumarate, succinate, and ethanol in the presence of sulfate. Sulfite, thiosulfate, and elemental sulfur were also used as an electron acceptors in the presence of lactate. However, both strains tolerated higher concentrations of NaCl (up to 17%) than all other Desulfovibrio species except Desulfovibrio halophilus, which tolerated a similar level of NaCl. The results of a 16S rRNA gene sequence analysis also placed the designated type strain, strain SEBR 2840, in the genus Desulfovibrio but revealed that this organism was significantly different from D. halophilus and all other validly described Desulfovibrio species. On the basis of our results, we propose that strain SEBR 2840T is a member of a new species of the genus Desulfovibrio, Desulfovibrio gabonensis. The type strain of D. gabonensis is strain SEBR 2840 (= DSM 10636).

Characterization of sulfate-reducing bacteria isolated from oil-field waters.

The occurrence and metabolic capacities of sulfate-reducing bacteria (SRB) were studied in 23 water samples taken from producing wells at 14 different sites. Oil fields in France, the North Sea, and the Gulf of Guinea were selected and classified according to physicochemical parameters (salinity ranging from 0.3 to 120 g.L-1 and temperature between 29 and 85 degrees C). After the distribution of SRB within oil fields was studied, several strains of SRB were isolated and characterized metabolically. Twenty of the thirty-seven strains were not related to any known species. Most of the identified strains were members of the genera Desulfovibrio and Desulfotomaculum by molecular, morphological, and physiological properties.

[Surgical approach to petroclival meningioma. Value of translabyrinthine approach extended to the petrous apex]. / Voies d'abord des méningiomes pétro-clivaux. Intérêt de la voie trans-labyrinthique étendue à l'apex pétreux.

Petro-clival meningiomas are rare tumors. Because of their deep location in the posterior fossa, many surgical approaches have been proposed, generally with severe post-operative morbidity and mortality. Thirty-six meningiomas of the petrous apex (34 posterior surface of petrous bone meningiomas, 2 clivus meningiomas) were operated, via a trans petrosal approach, from 1983 to 1993. In 14 cases, the trans-labyrinthine (TL) approach, extended by drilling the bone above the internal auditory canal (IAC) was performed (39%). In 18 cases the TL approach was extended in a subtemporal, transtentorial approach (50%). In one case (2.5%), after rerouting the facial nerve posteriorly, the TL approach was extended anteriorly in a transcochlear approach. The retro-sigmoïd approach was performed in one case (2.5%). The extended middle fossa approach was performed in two cases of clivus meningiomas (5%). Total excision was obtained in 27 cases (75%). By using the Laser, quality of resection is increased. Most complications and morbidity were encountered with tumors extending towards the cavernous sinus. Extended translabyrinthine approach allows total excision in most of cases of petro-clival meningiomas. For clivus tumors or tumors invading the cavernous sinus, the extended middle fossa approach and subtotal petrosectomy are proposed respectively.

Desulfovibrio longus sp. nov., a sulfate-reducing bacterium isolated from an oil-producing well.

A novel type of sulfate-reducing bacteria with unusual morphology was isolated from an oil-producing well in the Paris Basin. The cells of this bacterium, strain SEBR 2582T (T = type strain), are long, thin, flexible rods, contain desulfoviridin, and are physiologically similar to members of the genus Desulfovibrio. On the basis of 16S rRNA sequence data, this strain should be included in the genus Desulfovibrio. However, strain SEBR 2582T differs from other members of this genus morphologically, physiologically, and phylogenetically. Thus, a new species, Desulfovibrio longus sp. nov., is proposed for this organism.

[Clinical tolerance of CY 216 (Fraxiparin) in the prevention of thromboembolic accidents after neurosurgery]. / Etude de la tolérance clinique du CY 216 (Fraxiparine) dans la prévention des accidents thrombo-emboliques au décours de la neuro-chirurgie.

Clinical tolerance of CY 216 was assessed on 97 patients in two neurosurgical departments (Hopital Lariboisière and Hopital Beaujon, Paris). All the 97 patients were operated on by different cranial approaches, but always including bone flap. No thrombo-embolic event could be detected in this series. Post-operative intracranial hemorrhage was observed in 19 cases on the basis of CT scan performed on the first and seventh post-operative day. Among these 19 patients, 8 presented an increase of the hemorrhagic aspect between the 2 CT scan. However, clinical state of these patients improved and no reoperation was necessary to treat these hemorrhages. From this study, we consider that CY 216 is an effective mean of thrombo-embolism prevention with little hemorrhagic side-effect. Therefore, it can be recommended in the aftermath of intracranial surgical procedures.

[Effect of light intensity on the content of bacteriochlorophyll and on the growth of phototrophic marine sulfur bacteria]. / Influence de l'intensité lumineuse sur la teneur en bactériochlorophylle et sur la croissance de sulfobactéries phototrophes marines.

Eight strains of Chromatiaceae isolated from marine sediments are cultivated under light intensities of 50-5000 lx. A decreased in the light intensity brings about an increase in the specific bacteriochlorophyll content and also in the length of development. In certain strains, the increase in pigment contents partly compensates for the loss in light intensity, up to the maximum concentration of bacteriochlorophyll. This mechanism is only a physiological compatibility which ensures the survival of these organisms under feeble light intensities.