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Porphyromonas gingivalis and Tannerella forsythia secrete proteases, gingipains and KLIKK-proteases. In addition, T. forsythia produces a serpin (miropin) with broad inhibitory spectrum. The aim of this pilot study was to determine the level of expression of miropin and individual proteases in vivo in periodontal and peri-implant health and disease conditions. Biofilm and gingival crevicular fluid (GCF)/ peri-implant sulcular fluid (PISF) samples were taken from healthy tooth and implant sites (n = 10), gingivitis and mucositis sites (n = 12), and periodontitis and peri-implantitis sites (n = 10). Concentration of interleukin-8 (IL-8), IL-1β and IL-10 in GCF was determined by enzyme-linked immunosorbent assay. Loads of P. gingivalis and T. forsythia and the presence of proteases and miropin genes were assessed in biofilm by quantitative PCR, whereas gene expression was estimated by quantitative RT-PCR. The presence of P. gingivalis and T. forsythia, as well as the level of IL-8 and IL-1β, were associated with disease severity in the periodontal and peri-implant tissues. In biofilm samples harboring T. forsythia, genes encoding proteases were found to be present at 72.4% for karilysin and 100% for other KLIKK-protease genes and miropin. At the same time, detectable mRNA expression of individual genes ranged from 20.7% to 58.6% of samples (for forsylisin and miropsin-1, respectively). In comparison with the T. forsythia proteases, miropin and the gingipains were highly expressed. The level of expression of gingipains was associated with those of miropin and certain T. forsythia proteases around teeth but not implants. Cumulatively, KLIKK-proteases and especially miropin, might play a role in pathogenesis of both periodontal and peri-implant diseases.

Periodontal inflammation is one of the most common chronic inflammatory conditions in humans. Despite recent advances in identifying and characterizing oral microbiota dysbiosis in the pathogenesis of gum disease, just how host factors maintain a healthy homeostatic oral microbial community or prevent the development of a pathogenic oral microbiota remains poorly understood. An important determinant of microbiota fate is local antimicrobial proteins. Here, we report that chemoattractant protein chemerin, which we recently identified as a potent endogenous antimicrobial agent in body barriers such as the skin, is present in the oral cavity under homeostatic and inflammatory conditions. Chemerin and a chemerin-derived antimicrobial peptide are bactericidal against select bacteria strategically positioned in dental biofilm. Gingival crevicular samples from patients with gingivitis but not periodontitis contain abundant bioactive chemerin capable of inducing CMKLR1-dependent leukocyte migration. Gingipains secreted by the periodontopathogen P. gingivalis inactivate chemerin. Together, these data suggest that as an antimicrobial agent and leukocyte chemoattractant, chemerin likely contributes to antimicrobial immune defense in the oral cavity.

Various Arabidopsis thaliana mutants with defects in phytohormone signal transduction or the reception of light were analysed with regard to their stomatal response in a red, red/blue light irradiation programme. Stomatal response to light was detected with a customized gas exchange measurement device, optimized for the small model plant. Small transpiration-kinetic variations of the two wild-type lines Columbia (Col) and Landsberg erecta (Ler) were observed. A comparison of the mutant lines to the respective wild type revealed significant differences for the phytochrome A (phyA-103), the abscisic acid insensitive (aba3-2) and the auxin resistant (axr1-3) mutant. Furthermore, the zeaxanthin-less mutant line npq1-2 showed no alterations in stomatal response to light.

meability of these channel proteins for water (Preston et al., 1992). Recent findings concerning the sensitivity of aqua- For a long time, plant physiologists, on the other hand, porins to heavy metal ions and their possible con- have not accepted the requirement of these molecules for sequences to plant physiology are discussed. the simple reason that the majority of plants do not Furthermore, results obtained from heterologous possess organs or sites where comparable tremendous expression of plant aquaporin cRNAs in Xenopus amounts of water are transported through living cells. It oocytes are related to the situation in the plant. An was assumed that the water permeability of a biomemassessment of the significance of water flux regulation brane itself is suYcient for the requirements of plant by modification of the aquaporin protein or change cellular water movement (Fettiplace and Haydon, 1980; of gene activity is given and new data concerning Cullis et al., 1996). Since the counterparts of AQP1 were the selectivity of plasma membrane aquaporins are identified in the plant plasma membrane and tonoplast, presented. this opinion is questioned. To date the existence of aquaporins in virtually all living organisms, including

Membrane intrinsic proteins (MIPs) that facilitate water transport across biological membranes have been identified in many single- and multi-cellular organisms. Starting from an overview about the MIP protein family, common structures of aquaporins are described. A detailed report about tonoplast- and plasma-membrane-located plant aquaporins is given and several aspects about regulation of the corresponding genes, with emphasis on light-induced expression, are discussed. After reviewing techniques and results about the functional analysis of these proteins by heterologous and homologous expression systems, the plant-specific attributes of aquaporin regulation are considered, including a discussion about the use of solutions containing heavy-metal ions for inhibition of aquaporin-mediated water transport.

Almost all land plants have developed a symbiosis with arbuscular mycorrhizal fungi. Establishment of the association is accompanied by structural changes in the plant root. During arbuscule formation fungal hyphae penetrate the root apoplast and install highly specialized interfaces for solute transport between plant and fungus. The periarbuscular membrane which is part of the plant plasma membrane surrounding arbuscular structures was shown to harbour a high density of different transport systems. Among these also expression of aquaporins was described, which potentially can act as a low affinity transport system for ammonia or ammonium. The present study provides data for expression, localization and function of plant aquaporins in the periarbuscular membrane of mycorrhizal Medicago truncatula plants.

This paper gives a summary of a project to characterize a tobacco aquaporin. The cDNA and gene, including the 5' upstream region, for the tobacco aquaporin NtAQP1 has been isolated and the encoded protein characterized. The significance of promoter regions for an abscisic acid- and gibberellic acid-induced gene expression could be restricted to a region between -1450 and -1112 upstream of the transcription start point by transient transformation of a bicistronic vector into tobacco protoplasts. NtAQP1 expression in tobacco plants was found to be elevated in flowers, stems and roots. In roots, the protein was detected close to xylem vessels in pitch-like structures. Studies with a NtAQP1-GFP fusion indicated a plasma membrane location. For a functional analysis, the cDNA was expressed in Xenopus oocytes. NtAQP1 was found to be a heavy metal-insensitive aquaporin with additional permeability for glycerol. Mutation of a threonine at position 233 to a cysteine transformed NtAQP1 into a heavy metal-sensitive aquaporin.

The characterization of a plant MIP from tobacco (Nicotiana tabacum) regarding its function as an aquaporin and role in the plant will be presented.

Young laboratory mice were kept from birth in a surrounding with one dominating synthetical odor substance (geraniol, C10H18O; experimentals); the controls were bred under normal conditions. Between postnatal days 10 and 35 the development of the neural activity in the olfactory bulb and the response to the synthetical (geraniol) and a natural odor (nest material) were tested at 6 different stages of age. By means of a computer the total energy and the frequency composition (power spectra) of the electrophysiologically leaded potentials were analyzed at the time of stimulation and without stimulation. The developmental increment of neural activity was retarded at the experimentals, but the typical high-frequency waves (oscillations) appeared about 5-6 days earlier than in the controls. Both odor substances induced neural responses measured by energy and frequency changes in the power spectra. In controls none of the odors leads to noticeable changes in the composition of frequencies at days 10 and 14. Beginning at postnatal day 18 the odor substances of nest material evoked increasing neural reactions; at all stages of age geraniol induced only slight alterations in the power spectra. In the experimentals responses could be measured first at day 14. The changes in power spectra rapidly increased in the following 3 weeks and the responses to geraniol reached several times more intense levels than in the controls. The influence of permanent olfactory stimuli on the ontogenetic development of the olfactory bulb and the extreme plasticity of this system are discussed.