Taxonomic diversity of sputum microbiome in lung cancer patients and its relationship with chromosomal aberrations in blood lymphocytes.

Here we report a pilot-sized study to compare the taxonomic composition of sputum microbiome in 17 newly-diagnosed lung cancer (LC) patients and 17 controls. Another object was to compare the representation of individual bacterial genera and species in sputum with the frequency of chromosomal aberrations in the blood lymphocytes of LC patients and in controls. Both groups were male; average age 56.1 ± 11.5 in patients and 55.7 ± 4.1 in controls. Differences in the species composition of bacterial communities in LC patients and controls were significant (pseudo-F = 1.94; p = 0.005). Increased prevalence in LC patients was detected for the genera Haemophilus and Bergeyella; whereas a decrease was observed for the genera Atopobium, Stomatobaculum, Treponema and Porphyromonas. Donors with high frequencies of chromosomal aberrations had a significant reduction in the microbiome of representatives of the genus Atopobium in the microbiome and a simultaneous increase in representatives of the species Alloprevotella compared to donors with a low level of chromosomal aberrations in lymphocytes. Thus, a comparison of the bacterial composition in the sputum of donors with cytogenetic damages in theirs lymphocytes, warrants further investigations on the potential role of microorganisms in the process of mutagenesis in somatic cells of the host body.

Epidermoid carcinoma-derived antimicrobial peptide (ECAP) inhibits phosphorylation by protein kinases in vitro.

Animal peptide antibiotics are thought to mediate their cytotoxic and growth inhibitory action on bacteria, fungi, and cancer cells through a membrane-targeted mechanism. Although the membrane interactions of the peptide antibiotics and their penetration through the membranes have been studied in several models, the precise chain of events leading to cell death or growth arrest is not established yet. In this study we used in vitro kinase assays followed by imaging analyses to examine the effect of human cationic antimicrobial peptide ECAP on the activity of the protein kinases. We report that HPLC-grade ECAP is responsible for inhibition of EGFR autophosphorylation in plasma membrane fractions obtained from A-431 cells. The activity of ECAP is concentration dependent with a half-inhibitory concentration in the range of 0.1-0.2 microM. Marked decrease in autophosphorylation of immunoprecipitated non-receptor protein kinases belonging to different families, namely PKCmu, Lyn and Syk, is observed in the presence of as little as 0.2 microM of the peptide. Among the examined non-receptor protein kinases PKCmu was the most sensitive to the inhibitory action of ECAP, whereas Syk was inhibited least of all. ECAP exerted no detectable cytotoxicity on non-nucleate animal cells at concentrations up to 3 microM. The capability of ECAP to inhibit protein kinases at concentrations, that are at least 10 fold lower than antibacterial and cytotoxic ones, suggests that the protein kinases are possible intracellular targets for antimicrobial peptides. We suppose that inhibition of the protein kinases may provide a mechanism for the action of cationic antimicrobial peptides on host cells including tumour cells.

Possibility of multiquantal transmission at single inhibitory synapse in cultured rat hippocampal neurons.

Miniature, spontaneous and evoked inhibitory postsynaptic currents were studied using the whole-cell patch-clamp technique on synaptically connected cultured hippocampal neurons, at a holding potential of -75 mV. All experiments were done in tetrodotoxin-containing solution to exclude an action potential generation. Spontaneous miniature inhibitory postsynaptic currents were observed in Ca2+-free solution. The distribution of miniature inhibitory postsynaptic currents was skewed to larger current amplitudes and could be fitted reliably by one Gaussian with the mean at 10.0 +/- 1.2 pA (n = 7). Spontaneously occurring whole-cell spontaneous inhibitory postsynaptic currents were recorded in physiological solution (Ca2+ 2 mM). The average amplitude of spontaneously occurring currents depended on membrane potential and reversed at -18 +/- 5 mV (n = 5). The amplitude distribution of spontaneous inhibitory postsynaptic currents had one peak clearly detectable with the mean of 20.0 +/- 2.0 pA (n = 6) or 10.0 +/- 2.0 pA (n = 2). Inhibitory postsynaptic stimulus-evoked currents arose in responses to gradual activation of neurotransmitter release by direct extracellular electrical stimulation of a single presynaptic bouton by short depolarizing pulses. The current-voltage relation of the averaged amplitudes of evoked inhibitory postsynaptic currents was linear and reversed at potential predicted by the Nernst equation for corresponding intra- and extracellular Cl- concentrations. The time-course of decay of miniature, spontaneous and evoked inhibitory postsynaptic currents was fitted by a sum of two exponents and their time-constants were the same in the range of standard deviation. The stimulus-evoked inhibitory postsynaptic currents fluctuated with regard to the discrete aliquot values of their peak amplitudes in all the investigated synapses from a measurable minimum of about 8 pA to 200 pA. The evoked inhibitory postsynaptic currents were assumed as superimposition of statistically independent quantal events. Fitting amplitude histograms of evoked inhibitory postsynaptic currents with several Gaussian curves resulted in peaks that were equidistant with the mean space of 20 +/- 3 pA (n = 10), which was assumed as one quantum (quantum size) to construct the Poisson's distribution. A possibility of simultaneous multiquantal release at single inhibitory synapses of rat hippocampal neurons was discussed.