Levels of immunoglobulins of isotype IgG and IgG2 in subjects lacking formation of IgG antibodies against lipopolysaccharide of Chlamydia

In some patients with antibodies against LPS antigen of Chlamydia, specific immunoglobulins G are not present. The findings of isolated anti-LPS IgA/IgM antibodies are to be considered as possibly non-specifically or "false" positive. The aim of this study was to investigate if there is any difference in the level of total immunoglobulins of isotypes IgG and IgG2 in probands with isolated positivity anti-LPS IgA (i.e. without simultaneous presence of specific IgG; n = 34) as compared with a control group of subjects presenting positive anti-LPS IgA and IgG antibodies (n = 44). Antibodies against LPS antigen of Chlamydia were determined by ELISA method ("Chlamydien--rELISA", medac, Germany). Total immunoglobulin levels were determined by nephelometry using the following kits: "Immunoglobulin G Reagent, ARRAY Systems", Beckman Coulter, USA and "Human IgG2 Subclass Beckman ARRAY Kits", The Binding Site, UK. The measured values were related to the age-dependent laboratory standard values and the differences between the tested groups were statistically evaluated (chi(2) test). Decreased total IgG have been demonstrated in 4 (11.8 %) probands and in 5 (11.4 %) subjects of the control group; increased total IgG were found in 2 (5.9 %) probands and in 1 (2.3 %) subject of the control group. Decreased levels of total IgG2 were not determined in any proband and were found in 1 (2.3 %) subject of the control group. Increased levels of IgG2 were registered in 12 (35.3 %) probands and in 15 (34.1 %) control subjects. No statistically significant differences were found between the two groups. It can be concluded that no relationship was proved between the levels of total IgG and IgG2 and the absence of formation of specific anti-Chlamydia-LPS IgG. Further research will be necessary for the elucidation of this phenomenon (e.g. the presence of specific anti-LPS IgG in immunocomplexes).     

Analysis of articulation of fricative praealveolar sibilant "S" in control population

Defective pronunciation of one or more mother language phones, i.e. dyslalia, represents the most frequent speech impairment both in children and adult people. Cases of persisting speech disorder need professional approach and help. The aim of the study was to obtain a model of physiological articulation of the sibilant "s" in children. The method of FFT spectral analysis was made use of. Results will serve for further use in evaluation of speech impairment.     

Extracellular transduction events under pulsed stimulation in moth olfactory sensilla

In natural conditions, pheromones released continuously by female moths are broken in discontinuous clumps and filaments. These discontinuities are perceived by flying male moths as periodic variations in the concentration of the stimulus, which have been shown to be essential for location of females. We study analytically and numerically the evolution in time of the activated pheromone-receptor (signaling) complex in response to periodic pulses of pheromone. The 13-reaction model considered takes into account the transport of pheromone molecules by pheromone binding proteins (PBP), their enzymatic deactivation in the perireceptor space and their interaction with receptors at the dendritic membrane of neurons in Antheraea polyphemus sensitive to the main pheromone component. The time-averaged and periodic properties of the temporal evolution of the signaling complex are presented, in both transient and steady states. The same time-averaged response is shown to result from many different pulse trains and to depend hyperbolically on the time-averaged pheromone concentration in air. The dependency of the amplitude of the oscillations of the signaling complex on pulse characteristics, especially frequency, suggests that the model can account for the ability of the studied type of neuron to resolve repetitive pulses up to 2 Hz, as experimentally observed. Modifications of the model for resolving pulses up to 10 Hz, as found in other neuron types sensitive to the minor pheromone components, are discussed.     

Do phytotropins inhibit auxin efflux by impairing vesicle traffic?

Phytotropins such as 1-N-naphthylphthalamic acid (NPA) strongly inhibit auxin efflux, but the mechanism of this inhibition remains unknown. Auxin efflux is also strongly decreased by the vesicle trafficking inhibitor brefeldin A (BFA). Using suspension-cultured interphase cells of the BY-2 tobacco (Nicotiana tabacum L. cv Bright-Yellow 2) cell line, we compared the effects of NPA and BFA on auxin accumulation and on the arrangement of the cytoskeleton and endoplasmic reticulum (ER). The inhibition of auxin efflux (stimulation of net accumulation) by both NPA and BFA occurred rapidly with no measurable lag. NPA had no observable effect on the arrangement of microtubules, actin filaments, or ER. Thus, its inhibitory effect on auxin efflux was not mediated by perturbation of the cytoskeletal system and ER. BFA, however, caused substantial alterations to the arrangement of actin filaments and ER, including a characteristic accumulation of actin in the perinuclear cytoplasm. Even at saturating concentrations, NPA inhibited net auxin efflux far more effectively than did BFA. Therefore, a proportion of the NPA-sensitive auxin efflux carriers may be protected from the action of BFA. Maximum inhibition of auxin efflux occurred at concentrations of NPA substantially below those previously reported to be necessary to perturb vesicle trafficking. We found no evidence to support recent suggestions that the action of auxin transport inhibitors is mediated by a general inhibition of vesicle-mediated protein traffic to the plasma membrane.     

Immunomodulatory cytokines in human seminal plasma correlate with immunomodulatory steroids

7alpha-Hydroxy-dehydroepiandrosterone and its 7beta-hydroxyepimer, which act as local immunomodulatory agents, dehydroepiandrosterone, cortisol, and major androgens, together with four cytokines-interleukins 2, 4, 10, and IFN-gamma, reflecting the activity of TH1 or TH2 cells present in semen, were measured in seminal plasma from 35 male donors. Cortisol, dehydroepiandrosterone, its sulfate, 7-hydroxy-dehydroepiandrosterone epimers, testosterone, and estradiol were also measured in their blood serum. Steroids and interleukins in semen as well as serum steroids and seminal interleukins were mutually correlated to find out whether a relationship between immunomodulatory steroids and cytokines influencing the immune environment does exist. A highly significant (P<0.001) positive correlation was found between seminal 7beta-hydroxy-dehydroepiandrosterone and IFN-gamma, while a negative correlation was found between cortisol and IL-10. Highly significant positive correlations were also found between serum 7alpha-hydroxy-dehydroepiandrosterone and seminal IFN-gamma and between serum 7beta-hydroxy-dehydroepiandrosterone and seminal IL-2, while a negative correlation was found between serum dehydroepiandrosterone and seminal IL-10. Different and in some instances, even contradictory findings concerning the influence of dehydroepiandrosterone and cortisol on TH1 and TH2 cytokines were observed in seminal plasma as compared to those found by others in serum. The differences can be ascribed to the different environments of mucosal and systemic immunity. Correlations between the levels of steroids and cytokines in seminal plasma did not always correspond to the correlations between given cytokines and hormones in sera. The results, however, are in agreement with our recent finding of an autonomous production of these steroids in the male reproductive tract.     

Simple plasma work-up for a fast chromatographic analysis of homocysteine,cysteine, methionine and aromatic amino acids

Simplified sample workup obviating protein precipitation and eluent evaporation commonly employed in earlier reports using chloroformate-mediated derivatization of aminothiols prior to mass spectrometric (MS) detection is presented. The reduction of disulfides in plasma is accomplished with dithiothreitol within minutes. A simultaneous derivatization with ethyl chloroformate (ECF) and extraction of derivatives into organic phase takes place within seconds. Along with S-amino acids, also aromatic amino acids can be determined during a 5-min run. Gas chromatography with flame ionization detection (GC-FID) proved to be sensitive enough to reach plasma homocysteine levels. A prerequisite for a reliable quantitation was fulfilled under the given conditions. Intra-assay precision was <5%, recoveries from spiked plasma complete (101.2%), detection and quantitation limits for homocysteine came to <1 and 3 micro mol/l. Our results were in full agreement with those obtained by liquid chromatography (r=0.999 for homocysteine and 0.987 for cysteine), and were close to two homocysteine immunoassays (r=0.991 and 0.939, respectively).     

Analysis of state-specific phosphorylation of proteins by two-dimensional gel electrophoresis approach

In this paper we focus on the detection of specific state of protein phosphorylation within a complex protein mixture separated by two-dimensional gel electrophoresis followed by immunoblotting. The availability of antibodies that specifically recognize the phosphorylated residue(s) of proteins make this approach feasible as exemplified by the study of the regulatory mechanisms of the cell cycle. The major advantage of the presented approach is its relative simplicity and sensitivity that allows specific detection of protein phosphorylation and distinguishes different phosphorylation sites of target protein. Current findings demonstrate that this method represents a reasonable alternative to the use of other tools to study protein phosphorylation.     

Proteomics application exercise of the Swiss Proteomics Society: report of the SPS'02 session

After the success of the mass spectrometry (MS) round table that was held at the first Swiss Proteomics Society congress (SPS'01) in Geneva, the SPS has organized a proteomics application exercise and allocated a full session at the SPS'02 congress. The main objective was to encourage the exchange of expertise in protein identification, with a focus on the use of mass spectrometry, and to create a bridge between the users' questions and the instrument providers' solutions. Two samples were sent to fifteen interested labs, including academic groups and MS hardware providers. Participants were asked to identify and partially characterize the samples. They consisted of a complex mixture of peptide/proteins (sample A) and an almost pure recombinant peptide carrying post-translational modifications (sample B). Sample A was an extract of snake venom from the species Bothrops jararaca. Sample B was a recombinant and modified peptide derived from the shrimp Penaeus vannamei penaeidin 3a. The eight labs that returned results reported the use of a wide range of MS instrumentation and techniques. They mentioned a variety of time and manpower allocations. The origin of sample A was generally identified together with a number of database protein entries. The difficulty of the sample identification lay in the incomplete knowledge of the Bothrops species genome sequence and is discussed. Sample B was generally and correctly identified as penaeidin. However, only one group reported the full primary structure. Interestingly, the approaches were again varied and are discussed in the text.