No abstract

Mélanges represent a significant component of collisional and accretionary orogenic belts and occur widely around the world. Since its first introduction and use, the term has evolved to cover both processes (tectonic, sedimentary, and diapiric) and tectonic settings of mélange formation. The meaning and significance of various terms referring to the origin of ‘block-in-matrix chaotic rocks’ are still subject to debate. This study presents a historical overview of the evolving mélange concept and investigates the relationships between mélange types and their tectonic settings of formation. We investigate the contribution of mass-transport versus contractional deformation processes at the onset of mélange formation and throughout the evolution of different mélange types, and the nature of the continuum and transition from broken formations to true tectonic mélanges. A mélange is a mappable chaotic body of mixed rocks with a block-in-matrix fabric whose internal structure and evolution are intimately linked to the structural, sedimentary, magmatic, and metamorphic processes attending its origin. On the basis of a comparative analysis of exhumed, ancient on-land mélanges and modern tectonic environments, where mélange-forming processes are at work, such units are classified into those related to extensional tectonics, passive margin evolution, strike-slip tectonics, subduction zones, collisional tectonics, and intracontinental deformation. Sedimentation and contractional deformation contribute significantly to mélange formation in all these tectonic environments, although the internal structure of deposits is strongly controlled and overprinted by processes that prevail during the last stages of mélange formation in a single tectonic setting. Tectonic mélanges are commonly subordinate to broken formations and are restricted to narrow, elongated-to-coalescent fault zones, large-scale fault zones, and plate boundaries

No abstract

No abstract

This report describes the application of PCR fingerprinting for the identification of species and varieties of common dermatophytes and related fungi utilizing as a single primer the simple repetitive oligonucleotide (GACA) 4 . The primer was able to amplify all the strains, producing species-specific profiles for Microsporum canis, Microsporum gypseum, Trichophyton rubrum, Trichophyton ajelloi, and Epidermophyton floccosum. Intraspecific variability was not observed for these species. Instead, three different profiles were observed in the Trichophyton mentagrophytes group.Routine procedures for dermatophyte species identification rely on examination of the colony (pigmentation of the surface and reverse sides, topography, texture, and rate of growth) and microscopic morphology (size and shape of macroconidia and microconidia, spirals, nodular organs, and pectinate branches). Further identification characteristics include nutritional requirements (vitamins and amino acids) and temperature tolerance, as well as urease production, alkaline production of bromocresol purple medium, in vitro hair perforation, etc. (9, 16). Morphological and physiological characteristics can frequently vary; in fact, the phenotypic features can be easily influenced by outside factors such as temperature variation, medium, and chemotherapy (11) and therefore strain identification is often difficult.In the last few years genotypic approaches have proven to be useful for solving taxonomic problems regarding dermatophytes; in fact, genotypic differences are considered more stable and more precise than phenotypic characteristics (2, 11).Molecular methods, such as restriction fragment length polymorphism analysis of mitochondrial DNA (1,7,8) , have brought important progress in distinguishing between species and strains. However, most of these techniques (e.g., restriction fragment length polymorphism analysis, sequencing) are complex, laborious, time-consuming, and not easily employable for routine identification of dermatophytes; in contrast, PCR technology is simple, rapid, and, in the absence of specific nucleotide sequence information for the many dermatophyte species, able to generate species-specific or strain-specific DNA polymorphisms on the basis of characteristic band patterns detected by agarose gel electrophoresis (2, 11).This report describes the application of PCR fingerprinting for the identification of species and varieties of common dermatophytes and related fungi utilizing as a single primer the simple repetitive oligonucleotide (GACA) 4 previously used by Meyer and others to distinguish strains of Cryptococcus neoformans (12, 13) and species of the genus Candida (14 Furthermore, the study was conducted on various strains both from collections and from clinical isolation with the aim of finding the presence of an intraspecific variability.Strains. Out of a total of 140 strains selected for the study, 29 were obtained from the collection of the Institut Pasteur of Paris, France. One hundred eleven clinical isolates were re...