Search results for "IAC"

The complex life-cycle of a polymorphic prokaryote epibiont of the photosynthetic bacterium Chromatium weissei

1993

In natural populations of the anaerobic phototrophic bacterium Chromatium weissei, many cells support a prokaryotic epibiont. This epibiont appears in several forms, all from the life cycle of a single species. A typical epibiont consists of one to five flattened coccoid cells stacked one above the other, perpendicular to the C. weissei surface. The cells at the proximal and distal ends of the stack are 0.6 μm in diameter and 0.8 μm in length; mid-stack cells are slightly shorter. A typical three or four cell stack is 2 μm in length. Small mesosome-like inclusions in the distal cell are involved in the development of ‘droplet’ shaped cells which are released from the end of each stack. Thes…

Refractory coeliac disease: one step closer to the origin of aberrant lymphocytes.

2012

Aberrant intraepithelial lymphocytes (IELs) are the key feature of refractory coeliac disease type II (RCDII), but the cellular origin of these aberrant IELs remains unclear. In a recent paper Schmitz et al 1 further explored previously characterised aberrant IEL cell lines from four patients with RCDII by using a broad spectrum of cell specific markers, RNA array and immunological techniques, to compare these cell lines to IELs from the fetal intestine, the intestine of children and adults and the thymus. IELs are a heterogeneous population of lymphocytes with innate and adaptive features that inhabit the small and large intestine. IELs are important for the maintenance of tolerance to com…

Rickettsiae of the spotted fever group in dog fleas (Ctenocephalides spp.) in Western Sicily

1989

Mycorrhizal benefit differs among the sexes in a gynodioecious species

2010

Both plant sex and arbuscular mycorrhizal (AM) symbiosis influence resource acquisition and allocation in plants, but the interaction between these two components is not well established. As the different plant sexes differ in their resource needs and allocation patterns, it is logical to presume that they might differ in their relationship with AM as well. We investigate whether the association with AM symbiosis is different according to the host plant sex in the gynodioecious Geranium sylvaticum, of which, besides female and hermaphrodite plants, intermediate plants are also recognized. Specifically, we examine the effects of two different AM fungi in plant mass allocation and phosphorus …

Analysis of the epiphytic bryophyte diversity of Sicily

2009

Sicilian epiphytic bryophyte diversity, based on literature and unpublished data, is assessed both quantitatively and qualitatively. The total number of taxa found on trees or shrubs is 133 (116 mosses and 17 liverworts). Among them, 38 are customary epiphytic, 21 cortico-saxicolous, 13 are indifferent and 61 occasionally epiphytic taxa. The most represented families are Orthotrichaceae (19.1%), which consists above all of several typically corticicolous species, Pottiaceae (19.1%) and Brachytheciaceae (12.6%) which both include many taxa that mainly colonize rock or ground substrates. From the chorological point of view, temperate taxa (33.8%) prevail, followed by oceanic-Mediterranean tax…

Allium therinanthum (Amaryllidaceae), a new species from Israel

2014

Allium therinanthum, a new species of A. sect. Codonoprasum, is described and illustrated from southern Mt. Hermon (Israel). It is a late-flowering diploid species (2n = 16), growing on calcareous substrates of the mountain belt. It is a narrowly distributed geophyte, showing morphological relationships mainly with A. tardiflorum, a typical autumnal species also occurring in Israel within the pinewoods of Mt. Carmel. The morphology, karyology, leaf anatomy, ecology, conservation status and taxonomical relations are examined for both species. A taxonomic comparison with the most allied late flowering species of the sect. Codonoprasum is provided.

Increased number of Clostridium difficile infections and prevalence of Clostridium difficile PCR ribotype 001 in southern Germany

2008

In recent years, Clostridium difficile infection (CDI) has emerged as an increasing problem, both in in- and outpatients. In a rural region of southern Germany, the annual number of C. difficile toxin (Tcd)-positive patients has increased from 95 to 796 in the period from 2000 to 2007. Simultaneously, the proportion of positive tests among all Tcd examinations has risen from 7.0% to 12.8%, indicating that the higher number of affected patients was not solely due to an increase in the number of assays. Elevated numbers of CDI have recently been associated with outbreaks of the ribotype 027 strain, particularly in North America. This strain has also been isolated in Europe, including in Germa…

Diterpenes from Euphorbia segetalis

1998

Numerous new diterpenes including several with new skeletons have been obtained from Euphorbia segetalis.

The Follicle Cells of Styela Plicata (Ascidiacea, Tunicata): A Sem Study

2000

The morphological aspect of the follicle cells of Styela plicata eggs is described by means of scanning electron microscope investigations. The follicular layer is made of spaced, cylindrical box-like cells which are arranged hexagonally. They adhere to the egg through a complex network of membrane extensions making an overall thin layer on the vitelline coat. The walls of the follicle cells are plentifully provided with microvilli, filopodia and lamellipodia, which allow a connection among the cells. At their apical end lies a large vacuole containing a granule, probably involved in secretion. At insemination the majority of spermatozoa is distributed on the apical membrane of the follicle…

The effect of host mycorrhizal status on host plant-parasitic plant interactions

2001

Two pot experiments were conducted to examine three-level interactions between host plants, mycorrhizal fungi and parasitic plants. In a greenhouse experiment, Poa annua plants were grown in the presence or absence of an AM fungus (either Glomus lamellosum V43a or G. mosseae BEG29) and in the presence or absence of a root hemiparasitic plant (Odontites vulgaris). In a laboratory experiment, mycorrhizal infection (Glomus claroideum BEG31) of Trifolium pratense host plants (mycorrhizal versus non-mycorrhizal) was combined with hemiparasite infection (Rhinanthus serotinus) of the host (parasitized versus non-parasitized). Infection with the two species of Glomus had no significant effect on th…