New paradoxical three-finger toxin from the cobra Naja kaouthia venom: Isolation and characterization.

A new three-finger toxin nakoroxin was isolated from the cobra Naja kaouthia venom, and its complete amino acid sequence was established. Nakoroxin belongs to the group of "orphan" toxins, data on the biological activity of which are practically absent. Nakoroxin shows no cytotoxicity and does not inhibit the binding of α-bungarotoxin to nicotinic acetylcholine receptors of muscle and α7 types. However, it potentiates the binding of α-bungarotoxin to the acetylcholine-binding protein from Lymnaea stagnalis. This is the first toxin with such an unusual property.

Changes in the serum protein composition in mice with transplanted Ehrlich's carcinoma.

Injection of blood serum from mice with Ehrlich's carcinoma stimulates the growth of transplanted tumor, which proves the presence of tumor-specific factors in the serum. Experiments on (CBA×C57Bl/6)F1 male mice with transplanted Ehrlich's carcinoma demonstrated the appearance of new proteins in the serum, some of them are identified. The authors suggest continuing the search for tumor-associated factor by combining proteomic analytical methods and testing of identified candidate proteins for their effects on tumor growth.

[Solid state isotope hydrogen exchange for deuterium and tritium in human gene-engineered insulin].

The reaction of high temperature solid state catalytic isotope exchange in peptides and proteins under the action of catalyst-activated spillover hydrogen was studied. The reaction of human gene-engineered insulin with deuterium and tritium was conducted at 120-140° C to produce insulin samples containing 2-6 hydrogen isotope atoms. To determine the distribution of the isotope label over tritium-labeled insulin's amino acid residues, oxidation of the S-S bonds of insulin by performic acid was performed and polypeptide chains isolated; then their acid hydrolysis, amino acid analysis and liquid scintillation counts of tritium in the amino acids were conducted. The isotope label was shown to be incorporated in all amino acids of the protein, with the peptide fragment FVNQHLCGSHLVE of the insulin ß-chain showing the largest incorporation. About 45% of the total protein isotope label was incorporated in His5 and His10 of this fragment. For the analysis of isotope label distribution in labeled insulin's peptide fragments, the recovery of the S-S bonds by mercaptoethanol, the enzymatic hydrolysis by glutamyl endopeptidase from Bacillus intermedius and HPLC division of the resulting peptides were carried out. Attribution of the peptide fragments formed due to hydrolysis at the Glu-X bond in the ß-chain was accomplished by mass spectrometry. Mass spectrometry analysis data of the deuterium-labeled insulin samples' isotopomeric composition showed that the studied solid state isotope exchange reaction equally involved all the protein molecules. Biological studying of tritium-labeled insulin showed its physiological activity to be completely retained.

[Proteomic technologies for identification of serum potential biomarkers of autoimmune demyelinating polyneuropathies].

Time-of-flight MALDI mass spectrometry (MALDI-TOF-MS) profiling of blood serum of patients with Guillain-Barré syndrome (GBS, 36 samples), chronic inflammatory demyelinating polyneuropathy (CIDP, 24 samples) and practically healthy donors (HD) (35 samples) was carried out in order to identify potential biomarkers of autoimmune demyelinating polyneuropathies (ADP). To simplify the peptide-protein mixture of serum prior to MALDI-TOF-MS analysis samples were pre-fractionated on magnetic microparticles with a weak cation-exchange (MB-WCX) surface. Comparative analysis of mass spectrometric data using the classification algorithms (genetic and neural network-controlled) revealed a characteristic set of peaks, agreed change area with a high specificity and sensitivity of the differentiated mass spectrometry profiles of the blood serum of patients with DPNP and healthy donors (for GBS values of these characteristics reached 100 and 100, and for CIDP 94.1 and 100% respectively). Comparative analysis of mass spectrometric profiles of serum samples obtained from patients with GBS and CIDP, allowed to build a classification model to differentiate these diseases from each other, with a specificity of 88.9 and a sensitivity of 80%.

[Exploration and identification of Physcomitrella patens moss peptides].

In the current study the isolation and identification of Physcomitrella patens (Hedw.) B.S.G. moss peptides are described. Physcomitrella patens moss is actively used in recent years as a model organism to study the biology of plants. Protoplasts, protonemata and gametophores of the moss are demonstrated for the first time to contain diverse small peptides. From gametophores was isolated and identified 58 peptides that are fragments of 14 proteins, and from protonemata - 49 peptides, fragments of 15 proteins. It was found that the protonemata and gametophores Ph. patens, which are the successive stages of development of this plant, significantly different from each other as a peptide composition and the spectrum of the precursor protein of identified peptides. Isolation of protoplasts of the enzymatic destruction of cell wall protonemata accompanied by massive degradation of intracellular proteins, many of whom are proteins of photosynthesis, which is a characteristic response of plants to stress the impact of environmental factors. A total of moss protoplasts were isolated and identified 323 peptides that are fragments of 79 proteins.

[Endogenous hypometabolic-hypothermic factors and their possible application to life in the cold].

Hibernation is a natural model of Tolerance of hypometabolism, hypothermia, hypoxia, bradycardia, and longterm hypophagia. Here, we review recent advances in the isolation and identification of some natural endogenous regulators from hibernating and cold-adapted animals: proteins, peptides, and nonpeptide substances. We also discuss the employment of molecular, biochemical, and physiological bases of natural hypobiosis in ecology, cryomedicine, and the cryopreservation of genetic material from rare and endangered species. We suppose that our approaches can be extensively used (i) in medicine, when there is a need to slow down or suspend life processes for a short time; (ii) for the adaptation of humans to cold; and (iii) in long-term space flights.

[Solid phase reaction of hemoglobin with spillover hydrogen].

The reaction of high-temperature solid-state catalytic isotope exchange (HSCIE) between bovine hemoglobin and spillover hydrogen (SH) was studied. It was shown that, in the field of subunit contact, there is a significant decrease in ability for hydrogen exchange by SH. A comparison of the distribution of the isotope label in the hemoglobin alpha-subunit was carried out for the HSCIE reaction with the hemoglobin complex and with the free alpha-subunit. To this end, enzymatic hydrolysis of protein under the action of trypsin was carried out. The separation of tritium-labeled tryptic peptides was achieved by HPLC. Changes in availability of polypeptide chain fragments caused by complex formation were calculated using a molecular model. The formation of the protein complex was shown to lead to a decrease in the ability of fragments of alpha-subunits MFLSFPTTK (A(32-40)) and VDPVNFK (A(93-99)) for hydrogen replacement by tritium by almost an order of magnitude; hence, their availability to water (1.4 A) twice decreased on the average. The decrease in ability to an exchange of hydrogen by spillover tritium on the formation of hemoglobin complex was shown to be connected with a reduction in availability of polypeptide chain fragments participating in spatial interactions of subunits with each other. Thus, the HSCIE reaction can be used not only for the preparative obtaining of tritium-labeled compounds, but also for determining the contact area in the formation of protein complexes.

[Serum proteome profiling for ovarion cancer diagnosis using ClinProt magnetic bead technique and MALDI-TOF-mass-spectrometry].

Using reverse-phase (MB-HIC 8 and HB-HIC 18) weak cation exchange (MB-WCX) and metal affinity ClinProt magnetoc beads peptides and protein factions were obtained from human sera for their profiling by MALDI-TOF mass spectrometry. Proteome profiling of sera from I-IV stage ovarian cancer patients (47 women, average age 51) and from healthy women (47 subjects, average age 49) using MB-WCX beads allowed calculation of the best diagnostic models based on the Genetic Algorithm and Supervised Neural Network classifiers; these model generated 100% sensitivity and specificity when the test set of subjects was analyzed. Introduction of additional sera from patients with colorectal cancer (19) and ulcerous colitis (5) to the statistical model confirmed 100% ovarian cancer recognition. Statistical mass-spectrometry analysis of mass-spectrometry peak areas included to the diagnostic classifiers showed 3 peaks distinctive for ovarian cancer and 4 peaks distinctive for ovarian and colorectal cancer.

Analysis of proteins interacting with TRIP8b adapter.

Calcium-independent receptor of latrotoxin (CIRL) is an orphan heptahelical receptor implicated in regulation of exocytosis. To characterize molecular mechanisms of CIRL functioning, we searched for its intracellular partners using the yeast two-hybrid SR system with the cytoplasmic C-terminal fragment of CIRL as bait. One of the interacting proteins was identified as TRIP8b, a putative cytosolic adapter protein with multiple tetratricopeptide repeats. To understand functional significance of CIRL-TRIP8b interaction, we further isolated TRIP8b-interacting proteins by affinity chromatography of brain extracts on immobilized recombinant TRIP8b. Sixteen proteins were identified by mass spectrometry in the purified preparations. Clathrin and subunits of AP2 complex appeared to be the major TRIP8b-interacting proteins. Our data suggest a role of TRIP8b in receptor-mediated endocytosis.

Neuropeptide modulation of evoked responses of neurons in the medial septal region of hibernating ground squirrels in conditions of chronic isolation of the medial septal region from preoptic-hypothalamic structures.

Septal slices from hibernating ground squirrels were initially (for two weeks) subjected to basal separation of the septal region and were then used for studies of the effects of neuropeptides extracted from the brains of hibernating animals (TSKYR, TSKY, and DY) and monoaminergic neurotransmitters (noradrenaline and serotonin) on neuronal responses evoked by intraseptal electrical stimulation. Despite removal of a large complex of afferent connections and direct contacts with the preoptic region, the neurons retained their normal reactivity and the normal distribution of response types. Neuropeptides efficiently modulated responses, and had strong facilitatory effects on oligosynaptic short-latency responses consisting of single spikes. In most cases (78% of tests), effects on evoked activity were independent of effects on baseline discharge frequency. These data lead to the suggestion that neuropeptides have two influences on septal neurons: a direct, non-synaptic influence on the pacemaker potential responsible for baseline activity, and modulation of synaptic processes. Analysis showed that retention of descending septohippocampal connections was not critical for entry into hibernation and the tonic maintenance of this state. The effects of preoptic-hypothalamic mechanisms of hibernation determine the paradoxical latent excitability of septal cells, allowing the septohippocampal system to filter external signals and provide for urgent arousal of the forebrain during hibernation.

[Modulation of neuronal evoked responses to the medial septal area of hibernating ground squirrels by some neuropeptides after chronic disconnection between septum and preoptico-hypothalamic structures]. / Moduliatsiia neiropeptidami vyzvannykh otvetov neironov medial'noi septal'noi oblasti giberniruiushchikh suslikov v usloviiakh ee khronicheskoi izoliatsii ot preoptiko-gipotalamicheskikh struktur.

Effects of some neuropeptides identified in the brain of hibernators (TSKYR, TSKY, DY) and of monoaminergic neurotransmitters (noradrenaline and serotonin) on responses of the medial septal neurons evoked by intraseptal electrical stimulation were analyzed in slices taken from the ground squirrels with chronic basal undercutting of the septum. Despite the elimination of direct contacts with the preoptic area and afferents ascending in the medial forebrain bundle, the neurons retained almost normal level of reactivity and distribution of the reaction types. The neuropeptides effectively modulated neuronal responses of various types, including oligosynaptic short-latency single-spike responses. The latter were strongly facilitated by the neuropeptides. As a rule, changes in the responses to electrical stimulation were independent of the spontaneous activity shifts (in 78% of the tests). It was suggested that the neuropeptides exert a double influence on the septal neurons: direct nonsynaptic effects on the pacemaker potential responsible for the background activity and modulation of synaptic processes. Our experiments showed that descending influences of the septo-hippocampal system are not crucial for the entrance into the hibernation state and its tonic maintenance. The influences of the thermoregulatory--circadian structures of the preoptico-hypothalamic area determine the paradoxically increased latent excitability of septal neurons that allows the septo-hippocampal system to gate external stimuli and organize arousal of the forebrain during hibernation in case of emergency.

[Effect of chronic disconnection between septal area and hypothalamus on modulation of background activity of septal neurons by biologically-active substances in hibernators]. / Vliianie khronicheskogo raz''edineniia septal'noi oblasti i gipotalamusa na moduliatsiiu fonovoi aktivnosti septal'nykh neironov biologicheski aktivnymi veshchestvami u gibernantov.

Our previous work demonstrated paradoxically increased excitability of the medial septal (MS) neurons during hibernation of ground squirrels in comparison to waking animals. Recently this was supported by demonstration of higher efficacy of the neuropeptides identified in the brain of hibernators in septal slices of hibernating animals. To decide whether this increased excitability is determined by endogenous properties of the pacemaker septal neurons, or it depends on the influences of thermoregulatory-circadian mechanisms of preoptico-hypothalamic area, testing of the neuropeptides (TSKYR, TSKY, DY) and neurotransmitters participating in control of hibernation (serotonin and noradrenaline) was repeated on septal slices taken from the brain of hibernating animals two weeks after operation disconnecting it from the hypothalamus. Effects of neuropeptides in the deafferented hibernating animals neither quantitatively (low reactivity level), nor qualitatively (distribution of inhibitory and excitatory responses) differed from the data obtained in waking animals. Decrease of reactivity occurred at the expense of the neurons with regular pacemaker-like spontaneous activity. Thus, increased reactivity of the MS neurons to neuropeptides in hibernating animals depends mainly on influence of the hypothalamic centres controlling hibernation behavior upon pacemaker neurons of the MS. Contrary to the neuropeptides, serotonin and noradrenaline were highly effective in deafferented septum. They evoked stronger changes of background activity (shorter latencies and more rapid development of maximal shifts), presumably as a result of development of denervation hypersensitivity after deafferentation.

[Effects of the afferent stimulation on neurons in the medial septal region slices and their modulation by biologically active compounds in hibernating and waking ground squirrels]. / Vliianiia afferentnoi stimuliatsii na neirony v srezakh medial'noi septal'noi oblasti i ikh moduliatsiia biologicheski aktivnymi veshchestvami u giberniruiushchikh i bodrstvuiushchikh suslikov.

Responses of the medial septal (MS-DB) neurons to electrical stimulation of the medial forebrain bundle (MFB) and their modulation by some neuropeptides and monoamines were investigated in brain slices taken from two groups of ground squirrels-hibernating (HGS) and waking (WGS). Electrical stimulation evoked mostly inhibitory effects of various duration. Besides, responses by phase reset of the background rhythmic bursts and short-latency single spike responses were observed. The neuropeptides identified in the brain of hibernators differentially and reversibly modulated responses even in those neurons where they did not influence the level and pattern of the background activity. Effects of the peptides were state-dependent. E.g., the peptide TSKYR increased the duration of inhibitory effects in the HGS but shortened them in the WGS, while TSKY which had low efficacy in the HGS, increased the duration of inhibition in the WGS. Dipeptide DY depressed inhibitory components and augmented excitatory components of responses in the HGS but was much less effective in the WGS. Effects of noradrenaline and serotonin had stronger correlation with their influence on spontaneous activity. It is suggested that endogenous substances provide for the increased latent excitability and reactivity of the MS-DB neurons during seasonal hibernation. Thus, the MS-DB may function as a "sentry post" participating in signal detection and urgent arousal during hibernation.

[The state-dependent action of neuropeptides and monoamines on the background neuronal activity of the medial septal area in hibernating animals]. / Zavisiashchee ot sostoianiia deistvie neiropeptidov i monoaminov na fonovuiu aktivnost' neironov medial'noi septal'noi oblasti u gibernantov.

Neuronal activity of the medial septal area (MS-DB) was recorded extracellularly in brain slices from two groups of Yakutian ground squirrels Citellus undulatus--hibernating (winter period) and actively waking (summer period). Effects of three neuropeptides identified in the brain of hibernators (TSKYR, TSKY, and DY) and of two monoamines (serotonin and noradrenaline) on spontaneous activity were analyzed. All neuropeptides reversibly changed the levels of the background activity, but in the hibernating ground squirrels (HGS) the level of reactivity (47-56%) was significantly higher than in the waking ground squirrels (WGS, 25-30%). Serotonin also showed some tendency to higher efficacy in the HGS. Only noradrenaline was equally effective and had absolutely dominating excitatory effect in both states, although the level of excitation in the HGS was higher. All other substances evoked excitatory and inhibitory effects in various proportions. Their distribution was state-dependent, the rate of development, intensity and duration of the effects were greater in the HGS. The experiments confirmed the data on higher excitability and reactivity of the septal neurons in the state of hibernation. It is suggested that the tested neuropeptides may participate in the control of hibernation.

Effects of a number of short peptides isolated from the brain of the hibernating ground squirrel on the EEG and behavior in rats.

Intracerebroventricular administration of the peptides kyotorphin (Tyr-Arg), neokyotorphin (Thr-Ser-Lys-Tyr-Arg), and Asp-Tyr at doses of 4 and 8 micrograms altered the behavior of rats in a manner similar to that seen after similar administration of brain fractions from hibernating ground squirrels (Citellus undulatus), which contained these peptides; there were increases in orientational reactions, increases in the frequency of stereotypical scratching movements, grooming, yawning, hiccuping, and sneezing. Animals became drowsy after 15-20 min. Peptides and brain fractions also had similar effects on the EEG of rats. Brain fractions reduced theta and alpha rhythms and enhanced delta and beta frequencies. Increases in delta waves were seen with all peptides (a 4-microgram dose of kyotorphin produced alternating increases and reductions in the delta rhythm). Inhibition of theta and alpha rhythms after administration of Asp-Tyr and kyotorphin was more transient than after brain fractions. Increases in beta frequencies were seen only after administration of 8 micrograms of Asp-Tyr, the smaller dose not producing this effect.