Contribucion al estudio de las Tricopatias Piedricas de Venezuela

Summary In Venezuela, as in Colombia, Brazil and Argentine, two trichopathies of the piedra type were found, namely one with black knots, caused by Piedraia Hortai, and another with light-coloured knots, the so-called Colombian piedra. The last named trichopathy is caused by Trichosporium giganteum Behrend, 1890, not causing hair lesions, and by T. humahuaquensis Mazza et Niño, 1932, causing hair lesions; but it is possible that both species are referable to the same taxonomic entity.     

Isolation of keratinophilic fungi from soil in the vicinity of Bogota,Colombia

Soil collected from 54 areas in and around Bogota, Colombia were examined for the presence of keratinophilic fungi by theVanbreuseghem's hair baiting technique. The organisms isolated and frequency are indicated:Trichophyton terrestre, 33;T. ajelloi, 32;Chrysosporium keratinophilum, 30;Microsporon gypseum, 14; andM. fulvum, 1. The perfect stage,Nannizzia gypsea, 1; andArthroderma quadrifidum, 2; were observed growing on hair in three plates.The following organisms apparently have been reported for the first time from soil samples in Colombia:M. fulvum, T. ajelloi, T. terrestre, C. keratinophilum, N. gypsea, andA. quadrifidum.     

Submicroscopic structure of the membranous labyrinth

Summary Investigations were performed by light and electron microscope on the submicroscopic structure of the epithelium of Corti's organ in the white rat.Morphological and structural differences between the inner hair cells and the outer hair cells are revealed.The inner hair cells are closely inter-related with the inner supporting cells and have a polyhedral shape, whereas the outer hair cells look like cylinders and are surrounded by an intraepithelial fluid.The structural peculiarities consist of differences in the dimensions of the hairs, in the arrangement of cytoplasmic organoids and in the aspect of the receptoneural junction. In both sensory hair cells 4 zones of different structure can be distinguished from the surface inwards: apical zone, intermediate zone, perinuclear zone and receptoneuronal junction. The functional value of these different zones is discussed and compared with what has been demonstrated in other receptors.The pillar cells and the Deiters' cells are supporting cells which have a filamentous skeleton, composed of submicroscopic individual filaments. These filaments have a diameter of about 215 Å and present some analogies with the tonofilaments of the stratified squamous epithelium. The filaments are arranged differently in the pillar cells and in the Deiters' cells. Possible functional differences between these patterns are discussed.The reticular membrane is not an extracellular cuticle. It consists of intracellular cementitious material (like the terminal bars of the epithelial cells).The Hensen's and Claudius cells, the Böttcher's cells, the inner supporting cells, the inner and outer spiral sulcus cells are regular prismatic cells with few endoplasmic organoids and without filaments.This work is dedicated to the memory of the late Prof. L. Pietrantoni.     

Some aspects of the fine structure of the statocysts of the molluscsPecten andPterotrachea

Summary The statocyst ofPecten is composed of hair cells and supporting cells. The hair cells bear kinocilia and microvilli at their distal ends and the supporting cells bear microvilli. The cilia have a 9+2 internal filament content, and arise from basal bodies that have roots, basal feet and microtubular connections. Two different ciliary arrangements are described, one with a small number of cilia arranged in a ring, and another with many more cilia arranged in rows. Below the hair cells are probable synapses. A ciliated duct connects to the lumen of the static sac and passes through the centre of the static nerve. The hair cells in the statocyst ofPterotrachea bear kinocilia and microvilli. The possible importance of cilia and microvilli in the transduction process is discussed.We would like to thank ProfessorJ. Z. Young for bringing specimens ofPterotrachea from Naples and also the staff of the Stazione Zoologica for the provision of specimens, Dr.M. Land for providing specimens ofPecten, the Science Research Council (U.K.) for providing the electron microscope used in much of the study and also for a grant to one of us (V.C.B.), and Mrs.J. Parkers and Mr.R. Moss and Mrs.J. Hamilton for much photographic and technical assistance.     

Coexistencia de „Madurella Mycetomi” y de „Madurella Grisea” en una Misma Observacion de Maduromicosis Podal Negra

Summary The author reports on the clinical and mycological studies of a case of black-grain maduromycosis in a woman from Santa Maria (Province of Catamarca, Argentine).Cultures of black grains in Sabouraud medium have developed colonies ofMadurella mycetomi and also ofMadurella grisea Mackinnon, Ferrada &Montemayor, 1949.The author questioned, which of the two species is the etiological agent in the present case and he concluded that the microscopic aspect of the black grain permits to suppose thatMadurella mycetomi is the agent in this case.

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En homenaje al Prof. Tibor Benedek.     

Early postmortem changes in the Organ of Corti (guinea pig)

Summary Early post mortem changes in the Organ of Corti are described. 15 minutes after death, when kept at room temperature, 20° C (63° F), an oedematous swelling is observed within the cytoplasm of hair cells and nerve endings, the latter being more severe affected. After 30 minutes post mortem the mitochondria of the hair cells have also become significantly swollen. Three hours post mortem the general character of the hair cells is still recognizable, but most of the nerve endings have been completely destroyed. Acknowledgement. We wish to express our appreciation of the skilful technical assistance of Mrs. B. Flock, Miss A.-M. Lundberg, Miss Sonja Löfvenius, Mr. G. Bornholm and Mr. Rune Ragnefjell.This work was supported by grants from the Swedish Medical Research Council, the National Institute of Health grant (no NB 03956-02), the Therese and Johan Anderssons minne, the Gustav and Tyra Svenssons fund and the King Gustav V Research Fund.     

Considérations sur l'ubiquité duTrichophyton terrestre—Durié & Frey 1957—saprophyte du sol. Son inoculabilité

Résumé Les auteurs ont isolé 11 souches deTrichophyton terrestre—Durie &Frey 1957. Une de ces souches a été isolée d'un échantillon de terre qui leur avait été envoyé de Hanoi (Vietnam). Les 10 autres souches ont été isolées en Roumanie, à savoir 4 à Bucarest et 6 en province. Ces 10 souches ont été isolées des portions très limitées de terrain et—9 fois même—chacune d'un seul échantillon de terre, minutieusement exploré par le procédé deVanbreuseghem (mise en contact de la terre avec les cheveux). Les terrains, d'où l'on avait prélevé les échantillons de terre, ont été des jardins, des terrains rocheux, marécageux, steppes, abris pour le bois etc. LeTrichophyton terrestre a été trouvé toutes les fois qu'il a été cherché, sans aucune exception. Selon les auteurs, certains perfectionnements apportés au procédé deVanbreuseghem ont contribué largement à la réussite constante de cet isolement. Ils sont parvenus à provoquer, à la souris blanche, avec l'une des 11 souches mentionnées, une mycose expérimentale qui a envahi l'épiderme ainsi que les poils. La trichophytine produite par ces souches a été tout aussi active que la trichophytine produite par leTrichophyton mentagrophytes, et, en même temps, tout aussi spécifique. Les auteurs arrivent à la conclusion que leTrichophyton terrestre est probablement ubiquitaire dans le sol et qu'il n'est pas dépourvu de pouvoir pathogène. Au contraire, il est en voie d'adaptation à la vie parasitaire et peut être inclus dans le groupe des dermatophytes.

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Summary UsingVanbreuseghem's procedure (baiting moistened soil samples with filaments of hair), the authors were able to isolate 11 strains ofTrichophyton terrestre—Durie &Frey 1957. One of them has been recovered from a sample of soil sent from Hanoi (Vietnam), whereas the other strains have been recovered from different Rumanian soil samples. Four strains have been recovered from Bucarest and the other six ones from the province. Each strain has been isolated from a very small piece of ground and even, except for one strain, it was not necessary to control more than one sample of soil for each of them. The Rumanian soil samples were collected from gardens, rocky and marshy grounds, waste-lands, woodsheds and so on.Trichophyton terrestre has been recovered everywhere it was looked for, without any exception. The authors believe that the constantly positive results of their investigations concerning the presence ofTrichophyton terrestre in the soil, may be partially explained by some improvements they added toVanbreuseghem's method. The inoculation in white mice, guinea pigs and men were positive only in one case, a white mouse, in which the causative fungus has been found also in the hair. From the cultures of the isolated strains, the authors obtained a trichophytin, as active as the trichophytin produced byTrichophyton mentagrophytes, and not less specific. They conclude thatTrichophyton terrestre, as saprophyte of the soil, is probably an ubiquitous (cosmopolitan) mold and, moreover, it is not completely without pathogenity. On the contrary, it is on the way to become a parasite and, therefore, it may be included in the group of dermatophytes.

     

Dois novos taxa de Sphaeropsidaceae sôbre Palmaceae

Summary This paper deals with two new fungi studied on Palmaceae:Asteromella cocoes Batista &Bezerra n. sp. on leaves ofCocos nucifera L. andAsteropsis insectorum Batista &Bezerra n. sp. onCoccideae scales on leaves ofOenocarpus distichus Mart.

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Zusammenfassung Diese Arbeit beschreibt zwei neue Pilze, welche auf Palmaceae studiert wurden:Asteromella cocoes Batista &Bezerra n. sp. auf Blättern vonCocos nucifera L. undAsteropsis insectorum Batista &Bezerra n. sp. aufCoccideae Schuppen auf Blättern vonOenocarpus distichus Mart.

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Dedicado à Memória do Prof.Raffaele Ciferri     

habitat de Nocardia asteroides,Phialophora pedrosoi y Cryptococcus neoformans en Venezuela

Resumen Se estudiaron 336 muestras de tierra, madera y plantas provenientes de diferentes zonas del Edo. Mérida/Venezuela y Estados vecinos. Fueron inoculados cobayos y hamsters intratesticularmente y ratones por via endovenosa. Testículos y pulmones respectivamente fueron examinados por medio de cultivos e histológicamente.De 11 muestras se aislaronNocardia asteroides, de 6Phialophora pedrosoi y de unaCryptococcus neoformans.Se discuten las probables causas de porqué no se logró aislarParacoccidioides brasiliensis.

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Summary 336 samples of soil, wood and plants from several aereas of the State of Mérida/Venezuela and adjacent regions were studied.The samples were injected into the testes of guinea pigs and into mice intravenously. The testes and lungs of the animals respectively were cultured and examined histologically. From eleven samples were isolatedNocardia asteroides, from sixPhialophora pedrosoi and from oneCryptococcus neoformans.It is discussed, why it was not possible to isolateParacoccidioides brasiliensis.

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Zusammenfassung Es wurden 336 Erd-, Holz- und Pflanzenproben aus verschiedenen Gebieten des Staates Mérida/Venezuela und benachbarten Zonen untersucht. Das Material wurde Meerschweinchen intratestikulär und weissen Mäusen intravenös injiziert. Hoden und Lungen der Tiere wurden auf Nährböden verbracht und histologisch untersucht.Elfmal wurdeNocardia asteroides, sechsmalPhialophora pedrosoi und einmalCryptococcus neoformans isoliert und histologisch nachgewiesen. Es werden die möglichen Gründe diskutiert, warum es nicht gelangParacoccidioides brasiliensis zu isolieren.

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Del Instituto de Anatomía Patológica y Laboratorio de Micología de la Universidad de Los Andes, Mérida/Venezuela y del Laboratorio de Micología, Escuela de Medicina de la Universidad de Cincinnati/Ohio EEUU.

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Este trabajo pudo realizarse con la ayuda económica proporcionada por el Sr. Rector de la U.L.A., Dr.P. Rincón Gutiérrez a quien damos nuestras gracias más sinceras.A Wm. Bridge Cooke, Ph. D. y al Dr.G. A. de Vries agradecemos la identificación de las cepas dePhialophora pedrosoi.

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A los Dres.R. Kohler yP. N. Tablante G., y al Sr.Oswaldo Juergenson nuestro agradecimiento por la ayuda prestada en la recolección de las muestras.     

Quelques champignons pathogènes,isolés du sol roumain,par la méthode de l'inoculation intrapéritonéale à la souris

Resumé En injectant, selon le procédé d'Ajello et al., dans la cavité péritonéale de la souris blanche, une suspension de terre prélevée de divers endroits et en ensemençant après un délai de 6 à 8 semaines des fragments du foie, de la rate, des poumons et des reins de l'animal inoculé, les auteurs ont décelé dans le sol roumain la présence des champignons suivants:Geotrichum candidum, Trichophyton mentagrophytes, Keratinomyces ajelloi (une souche pathogène) etCoccidioides immitis. Selon les auteurs, cette méthode d'isolement est capable de compléter la méthode deVanbreuseghem pour l'isolement des dermatophytes du sol. La présence duCoccidioides immitis dans le sol roumain mérite une mention spéciale, la coccidioidomicose étant, jusqu'en 1961, inconnue en Roumanie.

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Summary By injecting the supernatant from aqueous suspensions of different rumanian soil specimens intraperitoneally into white mice and subsequent culture of their livers and spleens, according to the procedure ofAjello et al., the authors were able to recover the following fungi:Geotrichum candidum, Trichophyton mentagrophytes, Keratinomyces ajelloi (a pathogenic strain) andCoccidioides immitis (two strains). In the author's opinion, this indirect isolation procedure may complete the method developed byVanbreuseghem for isolating dermatophytes from soil. The presence ofCoccidioides immitis in the rumanian soils needs special mention owing to the fact that coccidioidomycosis was unknown in Rumania until 1961.

     

Nouvelles espèces de Torymides paléarctiques (Hym. Torymidae)

Summary In this paper four new palearctic species ofTorymidae are described:Monodontomerus gladiatus andTorymus favardi from South of France,Glyphomerus signifer from Austria andPseudotorymus amethystinus from Algeria.Torymus favardi is a parasite of bothDryocosmus australis mayr andAndricus singulus (mayr), whereasGlyphomerus signifer has been bred from galls ofDiplolepis spinosissimae (gir.).      

Role écologique deDigitalis purpurea dans la limitation naturelle des populations du puceron strié de la pomme de terreAulacorthum solani parAphidius urticae dans l'ouest de la France

Résumé En Bretagne les cultures de pommes de terre sont colonisées parAulacorthum solani,kltb,Macrosiphum euphorbiae thomas etMyzus persicae sulz. Lorsque le vol de contamination initiale par A.solani etM. persicae est de grande amplitude, le vol de dissémination est virtuellement absent, et inversement. Nous montrons que ceci est d? au très fort parasitisme qui affecte les populations dès leur installation sur les pommes de terre. En ce qui concerneA. solani, attaqué en particulier parAphidius urticae Hal. le r?le de la digitale en tant que producteur de pucerons et de parasites est mis en évidence. Le synchronisme entre la production de pucerons ailés et de parasites varie selon les biotopes et à ce titre la température para?t avoir une action prédominante.

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Summary In western France, the potato crops are regularly invaded byA. solani kltb,Myzus persicae sulz. andMacrosiphum euphorbiae thomas. Whenever the primary infestation by winged aphids is low, then the dissemination flight is relatively important and conversely (fig. 1). The reason is that aphidiids exert a good control as soon as aphid populations are building up. These parasites may be carried as eggs or young larvae in the alate aphids ofA. solani (table 1) and asD. purpurea constitutes one of its main winter host (A. solani is anholocyclic), the impcrtance of this plant was investigated as regards to aphid, parasite and hyperparasite production.Aphidius urticae hal-was the only parasite recorded so far with five hyperparasite species. On potato plants, too,A. urticae seems specifically concerned withA. solani otherwise attacked byAphidius picipes nees andAphidius ervi hal. It was shown some discrepancies between different biotopes as regards to the rate of parasitism at the same time (table 2) and attention is stressed on apparent differences between parasitization of apterous and winged instars (table 3), the importance of which is discussed regarding to the amount of winged invaders the foxglove may produce by the time the potato plants are shooting. Temperature appears to exert an important r?le in this respect.

     

Histoplasma capsulatum en el suelo de nuestro ambiente. I. Examenes micologicos

Resumen En 156 muestras de suelo del Edo. Médira/Venezuela y de zonas vecinas se encontróHistoplasma capsulatum en 13(8,3%) mediante la técnica deEmmons modificada porGeorg, Ajello &Papageorge ySilberg &Hinton.Dos muestras positivas provenian de cuevas, una en el Edo. Mérida, otra en el Edo. Zulia, al sur de Machiques.Las 11 muestras restantes eran preferentemente del piso de gallineros descubiertos de 4 poblaciones en la vertiente occidental de Los Andes venezolanos, al sur del Lago de Maracaibo.Mientras que se pudo determinar de ésta manera el habitat del hongo en la zona cerca de la carretera Panamericana, resultaron negativas todas las muestras de las zonas más altas del Edo. Mérida provenientes preferentemente de lugares a lo largo de la carretera Transandina.Se hacen algunos comentarios acerca de la epidemiología de la histoplasmosis comparando los resultados obtenidos en ésta encuesta con la procedencia de los sujetos con histoplasmosis en el material autópsico y biópsico y los resultados de las pruebas de histoplasmina en la población de nuestra región.Además de los cultivos del hígado y bazo de los ratones se realizaron concomitantemente exámenes histológicos.En otro lugar se dará a conocer los resultados de éstos estudios comparandolos con los hallazgos micológicos.

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Summary Histoplasma capsulatum was found in 13 (8,3%) out of 156 samples of soil from the State of Mérida (Venezuela) and adjacent zones by means of theEmmons technique modified byGeorg, Ajello &Papageorge andSilberg &Hinton.Two positive samples had been taken from caves located in the States of Mérida and Zulia (south of Machiques), respectively.The remaining eleven (positive) samples came predominantly from the soil of chicken yards found in four villages situated on the western slopes of the Venezuelan Andes south of Lake Maracaibo.Whilst it was possible in this way to determine the habitat of the fungus in the zone near the Pan-American Highway, all the samples from the higher zones of the State of Mérida — coming predominantly from sites along the Trans-Andian Highway — proved to be negative.Some comments are made on the epidemiology of histoplasmosis, comparing the results obtained in this investigation with the origin of the subjects showing signs of histoplasmosis in the autopsic and biopsic material and the results of the histoplasmine tests carried out amongst the population of our region.Apart from the cultivation of rat livers and spleens, histological examinations were made concomitantly. The results of this research work as well as a comparison with mycological findings will be published elsewhere.

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Zusammenfassung In 156 Bodenproben aus dem Staat Mérida/Venezuela und angrenzenden Gebieten fand sichHistoplasma capsulatum in 13 (8,3%). Die Proben wurden nach den Angaben vonEmmons, die später vonGeorg, Ajello &Papageorge undSilberg &Hinton modifiziert wurden, untersucht.2 positive Proben stammten aus je einer Höhle in den Staaten Mérida und Zulia.Die restlichen positiven Bodenproben stammten hauptsächlich aus unbedeckten Hühnerställen von 4 Dörfern am Westabhang der venezolanischen Anden, im Süden des Maracaibosees.Während der Habitat der Pilze auf diese Weise in der Gegend der panamerikanischen Autostrasse festgestellt werden konnte, waren alle Proben aus den hochgelegenen Gebrigszonen negativ.Es wird die Frage aufgeworfen, wo und wie sich unsere Patienten mit nachgewiesener Histoplasmose infiziert haben und wie die Histoplasminsensibilität der Bevölkerung in den Gebirgsgegenden zu erklären ist.Ausser den Kulturen von Mäuselebern und -Milzen wurden histologische Untersuchungen durchgeführt, über die an anderer Stelle berichtet werden soll.

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El doctorCapretti, Profesor de Micología de la Universidad de Los Andes, falleció en el mes de diciembre de 1960 a consecuencia de una infección pulmonar porHistoplasma capsulatum contraida durante la ejecución de éste trabajo.Publicamos los resultados obtenidos de éstos estudios en homenaje póstumo a nuestro querido amigo, colaborador y maestro.     

Hair morphology inPlantago sect.Coronopus (Plantaginaceae)

The presence of bottle-like hairs has been described in four hitherto uninvestigated taxa ofPlantago sect.Coronopus sensuDietrich. This hair type is a feature characteristic of sect.Coronopus.     

A new nematode trapping species of Dactylaria

Summary The paper deals with the isolation of a new predacious fungusDactylaria dasguptaii Shome &Shome from Indian soil. The fungus has been studied both in culture and soil. The predatory, morphological and reproductive characters of the new species accompanied by latin diagnosis has been described with illustrative diagrams.     

Effets édaphique et biotique de l'inversion pluviométrique des saisons,important facteur de pullulation des acridiens migrateurs dans le Sud-Ouest malgache

Summary In South-West Madagascar, the area from which outbreaks ofLocusta migratoria capito (Sauss.) andNomadacris septemfasciata (Serv.) proceed, a seasonal pluviometric inversion (an unusual occurence) will mean successful and simultaneous hatches due to edaphic and biotic effects. Edaphic effect: it maintains ground-moisture to optimum conditions for the eggs, which thereby are saved the over-dryness during the cool season and the over-moisture during the hot season in normal years. Rare and light rains in the hot season mean simultaneous hatches. Biotic effect: dryness at an undue time of the year disturbs the biological status, by jeopardizing the main enemy of the eggs:Caloglyphus berlesei Mich. (Acarina).      

Ecological study of soil fungi of an agricultural field in Allahabad

Summary The soil fungi from an agricultural field in Allahabad where sugarcane is being grown for many years, have been isolated from various depths during different seasons and were identified. The inter-relations of chemical composition of soil and distribution of fungi is also being shown here.The techniques for the isolation and the study of the fungus flora was that ofGoddard modified bySaksena &Mehrotra. Soil samples were examined from 1–6 depths in three seasons of the year and were mechanically and chemically analysed.For the isolation, soil dilution plate method, a modification ofMenzies' method, direct method ofWaksman, Rossi Cholodny Burried slide technique, and screened immersion plate method, were followed Fifty five different species of microfungi belonging to Phycomycetes, Ascomycetes and Fungi — Imperfecti were isolated and identified. The moisture contents, hydrogen-ion concentrations, carbon, nitrogen, phosphorus, calcium, magnesium and iron, etc., of the soil samples from 1–6 inches depths, were also studied.Out of these 12 species covering 9 genera belonged to the Phycomycetes, nine genera of Ascomycetes and nine genera of Fungi Imperfecti were recorded.P. multicolor Grigorieva-Monoilova &Poradielova, andP. roqueforti Thom.,Gliocladium vermoesoni (Biourge)Thom. andMasoniella grisea (Smith)Smith were recorded for the first time from Indian Soil. A new varietyChaetominum nigricolor Ames var.simplex was also isolated.     

Lachers d'Opius concolor [Hym.: Braconidae] dans des populations de printemps deDacus oleae [Dipt.: Trypetidae]

Résumé Un lacher du braconideOpius concolor Szepl. a été effectué au printemps au cours de la première génération de multiplication de la mouche de l'oliveDacus oleae Gmel. dans l'oliveraie de Delphes. Il permet de constater que: le parasite s'installe normalement aux dépens des larves réceptives (troisième stade), il est apte à parasiter les larves deD. oleae présentes en haut et en bas de l'arbre, les pontes des femelles s'étalent sur deux semaines, le parasite est susceptible d'être hébergé par les pupes qui s'enfouissent dans le sol. La mortalité larvaire naturelle due à des causes non parasitaires est importante, notamment dans les olives tombées au sol et dans celles de la partie basse et ombragée de l'arbre.

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Summary A release of the braconid parasitoidO. concolor Szepl. was made during spring (May) against the larval population of the olive fruit flyD. oleae Gmel. in a grove containing some trees which had heavily infested olive fruits which had overwintered. The parasitoid developed normally in the 3rd instar larvae of this population. Although it was present throughout the tree, during the 1st days it was more active in the upper part where 51% of receptive larvae were parasitized than in the lower where 18% were parasitized. After one week, these figures were 20% and 44% respectively. They have been calculated from counts ofDacus larvae containing either eggs or larvae.O. concolor had almost completely disappeared from the tree 2 weeks after the release because of fruit fall following high winds, although it was still possible to find both eggs and larvae in the appropriate host stages on the soil. The emergingO. concolor population was dominated by male adults, making up 74% of the numbers. The natural mortality ofD. oleae larvae not induced by the parasite factor was important in the area, especially in the fruits fallen onto the soil in which 28% of young larvae and 14% of 3rd instar larvae died. Higher mortality occurred from these factors in the upper crown than in the lower: 16% of young larvae and 7% of 3rd instar larvae died in the former situation but 7% and 2% respectively in the latter. Almost no parasitism from indigenous parasites was recorded.

     

Plasmid Transfer Detection in Soil using the Inducible lPR System Fused to Eukaryotic Luciferase Genes

We report a model system for plasmid transfer analysis using the regulated lambda phage right promoter, λPr, fused to luc and lucOR as repoter genes. We have demonstrated that the systems cI857-λPr::luc and cI857-λPr::lucOR are temperature-inducible in Escherichia coli but not in other Gram-negative bacteria analyzed, enabling detection of luminescence when plasmids were mobilized from E. coli to those Gram-negative backgrounds. Using light for the detection, we have observed plasmid transfer from E. coli harboring RK2 and R388 derived plasmids to Pseudomonas putida KT2440 (co-introduced with donors) and to indigenous microorganisms, in vitro and in nonsterile soil microcosms. The importance of nutrients for an efficient plasmid transfer in nonsterile soil microcosms has been confirmed. When plasmid transfer experiments were carried out into nonsterile soil microcosms, significant populations of indigenous transconjugants arose. This system provides efficient marker genes and avoids the use of antibiotics for the selection of transconjugants.     

Action de quelques fongicides sur la croissance mycélienne de trois espèces d'Entomophthorales

Résumé L'action,in vitro, de 34 fongicides sur la croissance mycélienne de 3 espèces d'Entomophthorales:Basidiobolus ranarum (Eidam),Conidiobolus osmodes (Drechsler) etEntomophthora virulenta (Hall & Dunn) [désignéEntomophthora nr.thaxteriana (Petch) parSoper & Bryan, 1974] a été examinée. Dans l'ordre croissant de leur sensibilité aux fongicides, les souches étudiées se classent comme suit:B. ranarum, E. virulenta etC. osmodes. Il existe une grande disparité dans l'activité des différents fongicides sur la croissance mycélienne des 3 espèces d'Entomophthorales. Certains fongicides sont peu ou pas actifs (chlorothalonil, éthirimol, oxychlorure de cuivre, soufre, etc.), d'autres agissent moyennement (captafol, dichlofluanide, mancozèbe, thirame, etc.); d'autres encore se révèlent très toxiques (bénodanil, chinométhionate, chloronèbe, triarimol). Mais il n'est pas simple de classer les fongicides en fonction de leur activité; un bon nombre d'entre eux possède un comportement hétérogène devant les 3 souches (carbendazime, oxycarboxine, 26019 RP, etc.). Dans l'ensemble, les fongicides systémiques se montrent plus efficaces sur la croissance mycélienne que les non systémiques.

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Summary The effect of 34 fungicides on the mycelial growth of 3 Entomophthorales species:Basidiobolus ranarum (Eidam),Conidiobolus osmodes (Drechsler) andEntomophthora virulenta (Hall & Dunn) was investigatedin vitro. The examination of growth was conducted in test tubes and five fungicidal concentrations were tested. The amount of growth of the various fungi in all treatments was expressed as a percentage of the growth of the control in order to evaluate the concentrations which reduce the growth speed by half. In the increasing order of their sensitivity to fungicides the strains under study could be classified in the following manner:B. ranarum, E. virulenta andC. osmodes. There is a great disparity between the action of the different fungicides upon the mycelial growth of the 3 Entomophthorales species. Some fungicides have little or no action (chlorothalonil, ethirimol, copper oxychloride, sulphur, etc.); others are more or less active (captafol, dichlofluanid, mancozeb, thiram, etc.); others again showthemselves to be highly toxic (benodanil, quinomethionate, chloroneb, triarimol). However it is not simple to classify the fungicides as a function of their activity; many of them react differently on the 3 species (carbendazim, oxycarboxin, 26019 RP, etc.). Overall, systemic fungicides are more effective on mycelial growth than non-systemic fungicides.