Search results for "lost"

The chemical composition of the essential oil of Ptilostemon gnaphaloides subsp. pseudofruticosus (Asteraceae) growing in Kythira Island, Greece

2021

Ptilostemon is a small genus of the subtribe Carduinae (Asteraceae) that includes 15 species as annual or perennial herbs or small shrubs, spread in the Mediterranean arch, from Crimea and Turkey to the Iberian Peninsula and Morocco. Several species of this genus have been studied for the content of non-volatile metabolites whereas few investigations have been carried out on their essential oils. In the present study the chemical composition of the essential oil from aerial parts of Ptilostemon gnaphaloides subsp. pseudofruticosus, belonging to Section Ptilostemon, endemic of South Greece and Turkey, and collected in the island of Kythira, was analyzed by GC-MS. The result showed the presen…

Bis-cyclohexyl-crown-ethers as allosteric carriers

1992

Abstract Several bis-cyclohexyl-crown-ethers have been synthesized and used as carriers for alkaline cations. These compounds should all show negative allosteric cooperativity, but only 1 exhibits an odd cation transport behavior across the liquid organic membranes.

Development of microbial populations in the anaerobic hydrolysis of grass silage for methane production

2010

Six batch leach bed (LB) reactors, installed in parallel and connected to a common upflow anaerobic sludge blanket reactor, were fed with grass silage and operated at 35 (+/-1) degrees C. The development and distribution of microorganisms, which firmly and loosely attached to solid materials, and presented in the leachate in the LB reactors, were investigated by 16S rRNA gene-based terminal restriction fragment length polymorphism and clone library analyses. The phylotypes and their relative abundance changed in the respective bacterial community throughout the 49-day run and showed differences between the communities. Large numbers of phylotypes were detected from day 10 onwards. On day 17…

Morphological changes in adherent cells induced by Clostridium difficile toxins.

1991

Diagnóstico microbiológico de las infecciones gastrointestinales

2009

Resumen Las infecciones agudas del tracto gastrointestinal figuran entre las enfermedades infecciosas más frecuentes. En esta revisión se examinan diversas técnicas para diagnosticar las gastroenteritis que ocasionan bacterias, virus y parásitos. El coprocultivo es el método de elección para el diagnóstico de las infecciones bacterianas intestinales, aunque las infecciones por Clostridium difficile se pueden diagnosticar mediante la detección de las toxinas A y B en las heces y las infecciones por Escherichia coli diarreagénicas se pueden diagnosticar mediante la detección por reacción en cadena de la polimerasa de factores de virulencia específicos de los diversos enteropatotipos. Las técn…

Selective growth-inhibitory effect of 8-hydroxyquinoline towards Clostridium difficile and Bifidobacterium longum subsp. longum in co-culture analyse…

2014

The major risk factor for Clostridium difficile infection (CDI) is the use of antibiotics owing to the disruption of the equilibrium of the host gut microbiota. To preserve the beneficial resident probiotic bacteria during infection treatment, the use of molecules with selective antibacterial activity enhances the efficacy by selectively removing C. difficile. One of them is the plant alkaloid 8-hydroxyquinoline (8HQ), which has been shown to selectively inhibit clostridia without repressing bifidobacteria. Selective antimicrobial activity is generally tested by culture techniques of individual bacterial strains. However, the main limitation of these techniques is the inability to describe …

Cloning of Clostridium difficile toxin B gene and demonstration of high N-terminal homology between toxin A and B.

1990

High titered Clostridium sordellii lethal toxin antiserum, cross-reactive with C. difficile cytotoxin B (ToxB), was used to isolate toxB fragments from a C. difficile expression library. Recombinant clones containing toxB fragments of the 5' and 3' end were isolate. A 2.5-kb HincII fragment of chromosomal DNA overlaps both groups of clones. A partial restriction map of the total toxB gene is presented. The gene is positioned upstream of utxA and toxA, toxB has a size of 6.9 kb, corresponding to a 250-kDa polypeptide. A partial sequence of the 5' end of toxB was determined. The sequence contains 398 bp upstream of toxB with a putative Shine-Dalgarno box (AGGAGA) and 609 bp of the toxB open r…

Recombinant epidermolytic (exfoliative) toxin A of Staphylococcus aureus is not a superantigen

1992

The epidermolytic (exfoliative) toxins produced by Staphylococcus aureus cause epidermolysis and skin blistering. In addition, they have been implicated to belong to the group of T lymphocyte stimulating molecules known as "superantigens". Here we show that recombinant epidermolytic toxin A produced in S. aureus is not mitogenic for human and murine T lymphocytes. We discuss the possibility that minute contaminations of highly mitogenic exoproteins may cause the mitogenicity in several proteins that are reported to be superantigens.

Colonization Resistance of the Gut Microbiota against Clostridium difficile

2015

Antibiotics strongly disrupt the human gut microbiota, which in consequence loses its colonization resistance capacity, allowing infection by opportunistic pathogens such as Clostridium difficile. This bacterium is the main cause of antibiotic-associated diarrhea and a current problem in developed countries, since its incidence and severity have increased during the last years. Furthermore, the emergence of antibiotic resistance strains has reduced the efficiency of the standard treatment with antibiotics, leading to a higher rate of relapses. Here, we review recent efforts focused on the impact of antibiotics in the gut microbiome and their relationship with C. difficile colonization, as w…

Long-term lacustrine paleo-productivity and/or paleo-anoxia trends controlled by eccentricity cycles in the continental Autun Basin (France) at the C…

2020

<p>The organic-rich lacustrine beds of the Autun Basin (France) were deposited from the late Gzhelian (late Carboniferous) to the Sakmarian (early Permian), encompassing the Carboniferous-Permian boundary (∼299 Ma). Those deposits reach up to 1500 m thick, and correspond to a tropical, intra-mountainous late-orogenic basin infilling associated with the Variscan orogeny (Marteau, 1983; Schneider et al., 2006). Organic-rich and laminated facies are attributed to distal lacustrine environments which sometimes alternate with silty to sandy rich deltaic depositional environments (Mercuzot et al., 2019). The four successive formations (respectively the Igornay, Muse, …