Comparative Study of the Effect of Snake Venoms on the Growth of Ciliates Tetrahymena pyriformis: Identification of Venoms with High Antiprotozoal Activity.

To search for compounds with antiprotozoal activity, effects of snake venoms on the ciliates Tetrahymena pyriformis was studied. T. pyriformis from subkingdom of Protozoa, including the protozoal pathogens, was used as a model organism to select the venoms that are the most active against parasitic protozoans. Various concentrations of venoms were added to the cells, and the cells that survived after 24 h were counted. Among the six snake species from the Viperidae family, the venom of the viper Vipera berus, which completely killed the cells at 49 µg/mL, was the most active. Among four species from the Elapidae family, the previously studied cobra venoms containing cytotoxins with strong antiprotozoal activity as well as the venom of krait Bungarus multicinctus (10 µg/mL) were the most active. The venoms of the pit vipers and Nikolsky's viper did not show any activity at 12.5 mg/mL. Thus, the venoms of V. berus and B. multicinctus are promising for the isolation of new antiprotozoal compounds.

New Plant Species Showing Antiprotozoian Activity.

The effects of extracts of ten plant species from Russia and five species from Vietnam on the growth and survival of ciliates Tetrahymena pyriformis were studied. T. pyriformis belongs to the subkingdom Protozoa, which also includes pathogens of protozoan infections. Extraction of dried plants was carried out with acidic and alkaline aqueous solutions, as well as with an aqueous ethanol. Various amounts of extracts were added to the ciliate cells, and the number of cells survived after incubation for 1 and 24 h was recorded. We found that our samples of several plants, including wormwood, harmala, and licorice, similarly to those studied earlier, exhibit antiprotozoal activity, which may indicate that the secondary metabolites are the same in plants from different regions. Using the ciliate T. pyriformis as a model organism, the presence of antiprotozoal activity in extracts of lilac, chondrilla, cinquefoil, hop, and elm was shown for the first time.

Blockers of Nicotinic Acetylcholine Receptors Delay Tumor Growth and Increase Antitumor Activity of Mouse Splenocytes.

Blockade of α6, α3ß2, α9α10, and α7 subtypes of nicotinic acetylcholine receptors slows tumor growth in vivo, increases cytotoxic activity of splenocytes from tumor-bearing mice, and, to some extent, reduces the viability of Ehrlich carcinoma cells in vitro. These data indicate that nicotinic acetylcholine receptors are involved in oncogenesis, affecting the survival of tumor cells, inter alia, via modulation of the antitumor immunity.

Ascending Si diffusion into growing GaN nanowires from the SiC/Si substrate: up to the solubility limit and beyond.

We report a novel mechanism that allows the incorporation of Si into GaN nanowires up to and beyond the solubility limit. This mechanism is documented during the growth on vicinal (misoriented) SiC/Si hybrid substrates having the step bunches. Nanowires that are grown at these locations become heavily Si doped. Such high Si concentrations were verified by secondary-ion mass spectrometry. Photoluminescence data also point to very high carrier concentrations. Moreover, Raman spectroscopy together with quantum chemical modelling shows the build up of Si into Ga sites and indicates even the possibility of the formation of a Ga(Si)N solid solution. The microscopic mechanism responsible for heavy doping and even alloying is diffusion driven by the mechano-chemical effect, which allows for the extremely efficient injection of Si atoms into the nanowires from the step bunches at the vicinal SiC/Si substrates.

[Evolution of enhanced recovery after surgery: from the beginning of the study of stress to the introduction in emergency surgery]. / Évoliutsiia kontseptsii uskorennogo vosstanovleniia posle operatsii: ot istokov ucheniia o stresse do ispol'zovaniia v neotlozhnoi khirurgii (obzor literatury).

Effectiveness of enhanced recovery program is being earnestly confirmed in various surgical areas. Certain aspects of fast track rehabilitation are analyzed in the article.

Low-molecular-weight compounds with anticoagulant activity from the scorpion Heterometrus laoticus venom.

Low-molecular-weight compounds with anticoagulant activity were isolated from the scorpion Heterometrus laoticus venom. The determination of the structure of the isolated compounds by nuclear magnetic resonance and mass spectrometry showed that one of the isolated compounds is adenosine, and the other two are dipeptides leucyl-tryptophan and isoleucyl-tryptophan. The anticoagulant properties of adenosine, which is an inhibitor of platelet aggregation, is well known, but its presence in scorpion venom is shown for the first time. The ability of leucyl-tryptophan and isoleucyl-tryptophan to slow down blood clotting and their presence in scorpion venom are also established for the first time.

A study of ribonuclease activity in venom of vietnam cobra.

BACKGROUND: Ribonuclease (RNase) is one of the few toxic proteins that are present constantly in snake venoms of all types. However, to date this RNase is still poorly studied in comparison not only with other toxic proteins of snake venom, but also with the enzymes of RNase group. The objective of this paper was to investigate some properties of RNase from venom of Vietnam cobra Naja atra. METHODS: Kinetic methods and gel filtration chromatography were used to investigate RNase from venom of Vietnam cobra. RESULTS: RNase from venom of Vietnam cobra Naja atra has some characteristic properties. This RNase is a thermostable enzyme and has high conformational stability. This is the only acidic enzyme of the RNase A superfamily exhibiting a high catalytic activity in the pH range of 1-4, with pHopt = 2.58 ± 0.35. Its activity is considerably reduced with increasing ionic strength of reaction mixture. Venom proteins are separated by gel filtration into four peaks with ribonucleolytic activity, which is abnormally distributed among the isoforms: only a small part of the RNase activity is present in fractions of proteins with molecular weights of 12-15 kDa and more than 30 kDa, but most of the enzyme activity is detected in fractions of polypeptides, having molecular weights of less than 9 kDa, that is unexpected. CONCLUSIONS: RNase from the venom of Vietnam cobra is a unique member of RNase A superfamily according to its acidic optimum pH (pHopt = 2.58 ± 0.35) and extremely low molecular weights of its major isoforms (approximately 8.95 kDa for RNase III and 5.93 kDa for RNase IV).

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.

Suppression of Ehrlich carcinoma growth by cobra venom factor.

Cobra venom factor (CVF) depletes the complement system of the blood by forming stable convertase C3/C5 of the alternative pathway. We found that CVF from the Thailand cobra venom slows down the growth of subcutaneous Ehrlich carcinoma (EC) in mice at a dose of 1.7 nmol/g. Previously, we described a similar effect for the nerve growth factor (NGF) from the venom of this cobra. However, these factors did not exhibit either synergy or additive effect. On the contrary, they neutralized the antitumor effect of each other when they were administered simultaneously. Therefore, on the one hand, the NGF antitumor effect against EC manifests itself under the conditions of inflammation, and normal functioning of the complement system is necessary for this effect to occur. On the other hand, suppression of the humoral immune system leads to a slowdown of the EC growth, but administration of NGF prevents this.

α-conotoxins revealed different roles of nicotinic cholinergic receptor subtypes in oncogenesis of Ehrlich tumor and in the associated inflammation.

Multiple injections of conotoxin MII, a blocker of alfa3-ß2 and alfa6-containing subtypes of nicotinic acetylcholine receptors (n-AChRs), as well as conotoxin ArIB11L16D, a blocker of alfa7 subtype n-AChR, at a dose of 1 nmol/kg reduce both the lactate dehydrogenase level in tumor cells and the inflammatory leukocyte infiltration in tumor tissue in mice bearing Ehrlich carcinoma. The first stage of pathomorphism was detected in the tumor tissue after the treatment with the ArIB11L16D conotoxin, whereas the second stage was observed after the treatment with conotoxins RgIA and MII. Only MII injections led to a significant reduction in tumor growth. Our results show the involvement of n-AChRs in the regulation of metabolic processes and cell-cell interactions related to carcinogenesis and tumor-associated inflammation.

Micro-Raman Mapping of 3C-SiC Thin Films Grown by Solid-Gas Phase Epitaxy on Si (111).

A series of 3C-SiC films have been grown by a novel method of solid-gas phase epitaxy and studied by Raman scattering and scanning electron microscopy (SEM). It is shown that during the epitaxial growth in an atmosphere of CO, 3C-SiC films of high crystalline quality, with a thickness of 20 nm up to few hundreds nanometers can be formed on a (111) Si wafer, with a simultaneous growth of voids in the silicon substrate under the SiC film. The presence of these voids has been confirmed by SEM and micro-Raman line-mapping experiments. A significant enhancement of the Raman signal was observed in SiC films grown above the voids, and the mechanisms responsible for this enhancement are discussed.

Measurement of tensor analyzing powers in deuteron photodisintegration.

A new accurate measurement of the tensor analyzing powers T20, T21, and T22 in deuteron photodisintegration has been performed. Wide-aperture nonmagnetic detectors allowed broad kinematic coverage in a single set up: E(gamma)=25 to 600 MeV, and theta(p)(cm)=24 degrees to 48 degrees and 70 degrees to 102 degrees . The new data provide a significant improvement over the few existing measurements. The angular dependency of the tensor asymmetries in deuteron photodisintegration is extracted for the first time.

Influence of phospholipases A2 from snake venoms on survival and neurite outgrowth in pheochromocytoma cell line PC12.

To determine whether the ability to induce neurite outgrowth in rat pheochromocytoma cell line PC12 is characteristic of phospholipases of different types, we have studied the influence of phospholipase A(2) (PLA2) from cobra Naja kaouthia venom and two PLA2s from viper Vipera nikolskii venom on PC12 cells. Phospholipases from the viper venom are heterodimers in which only one of the subunits is enzymatically active, while PLA2 from the cobra venom is a monomer. It was found that all three PLA2s induce neurite outgrowth in PC12. The PLA2 from cobra venom exhibits this effect at higher concentrations as compared to the viper enzymes. We have not observed such an activity for isolated subunits of viper PLA2s, since the enzymatically active subunits have very high cytotoxicity, while the other subunits are not active at all. However, co-incubation of active and inactive subunits before addition to the cells leads to a marked decrease in cytotoxicity and to restoration of the neurite-inducing activity. It has also been shown that all enzymatically active PLA2s are cytotoxic, the PLA2 from cobra venom being the least active. Thus, for the first time we have shown that PLA2s from snake venoms can induce neurite outgrowth in PC12 cells.

Measurement of the tensor analyzing powers T20 and T21 in elastic electron-deuteron scattering.

The tensor analyzing power components T20 and T21 have been measured in elastic electron-deuteron scattering at the 2 GeV electron storage ring VEPP-3, Novosibirsk, in a four-momentum transfer range from 8.4 to 21.6 fm(-2). A new polarized internal gas target with an intense cryogenic atomic beam source was used. The new data determine the deuteron form factors G(C) and G(Q) in an important range of momentum transfer where the first node of the deuteron monopole charge form factor is located. The new results are compared with previous data and with some theoretical predictions.

[Cobra venom contains a protein belongs to the CRISP family]. / Iad kobry soderzhit belok CRISP-tipa.

Amino acid sequences of several fragments of the 25 k protein (molecular mass 24,953 Da) previously isolated from cobra Naja kaouthia (Kukhtina et al. Bioorg. Khim., 2000, vol. 26, pp. 803-807) were determined. Their comparison with the primary structures of known proteins showed that the 25 k protein belongs to the CRISP family and is the first protein of this type identified in cobra venoms.

[MALDI-mass spectrometry for identification of new proteins in snake venoms]. / MALDI-mass-spektrometriia dlia identifikatsii novykh belkov v iade zmei.

By MALDI MS, we searched cobra venoms for new low-content polypeptides. A number of new proteins with molecular masses 7-25 kDa, characteristic of the known snake protein toxins, were identified, with the content of one of them less than 0.02%.

[Effect of stress on the development of deafferentation pain syndrome in rats after sciatic nerve transection]. / Vliianie stressa na razvitie deafferentatsionnogo bolevogo sindroma u krys posle pererezki sedalishchnogo nerva.

Effect of immobilization and painful stress on the development of deafferentation pain syndrome, appeared after sciatic nerve section, has been studied in Wistar rats. It has been determined that both immobilization and painful stress favour the appearance of pain syndrome in rats without clinical signs of pain syndrome up to the moment of stress influence. There has been made a conclusion that both immobilization and painful stress favour the appearance of pathologic algic system, which is the basis of pain syndrome. The fact that stress can cause analgesia in normal animals in contrast to those with potential pain syndrome is explained to different mechanisms of physiological and pathological pain.