Membrane mechanisms of the effect of alkylating cytostatic agents

The data bearing witness to realization of the cytostatic activity of alkylating agents by means of interaction with cell membrane receptors was obtained. Alkylating agents block receptors of the polyphosphoinositol system. It is shown that chloralkylamines inhibiting sites coincide with M-++cholinomimetics and alpha-adrenergic receptors, inhibitors of H-histamine receptors, cyclo- and lypoxigenase inhibitors. Such likeness is determined by identical structures of the molecule active part, and quantum-chemical calculations.     

Modification of low density lipoprotein by desialylation causes lipid accumulation in cultured cells: discovery of desialylated lipoprotein with altered cellular metabolism in the blood of atherosclerotic patients

Low density lipoprotein (LDL) isolated from the blood of healthy donors was partially desialylated by incubating the lipoprotein with sialidase (neuraminidase). The addition of LDL treated with neuraminidase to cultured human aortic intimal cells of smooth muscle origin caused a substantial increase in intracellular cholesteryl esters, free cholesterol and triglycerides. Cultured cells took up and degraded desialylated LDL much more effectively than untreated (native) LDL. LDL were also isolated from an atherogenic blood plasma of patients with coronary artery disease, i.e. the plasma capable of inducing the accumulation of lipids in cultured cells. Patients' LDL, similarly to the mother plasma, were atherogenic, i.e. stimulated the accumulation of intracellular lipids. LDL isolated from nonatherogenic plasma of healthy donors proved to be nonatherogenic. Atherogenic patients' LDL had a 2- to 5-fold lower level of sialic acid as compared with nonatherogenic LDL of healthy donors. The uptake and degradation of atherogenic patients' LDL were much more effective than in the case of nonatherogenic LDL of healthy donors. We assume that atherogenic properties of LDL obtained from patients' blood plasma are explained exactly by a low sialic acid content.     

Two molecular forms of pea ferredoxin in the electron transport chain of chloroplasts

The effects of two molecular forms of water-soluble ferredoxin (Fd I and Fd II) on the kinetics of electron transport in bean chloroplasts (class B) were studied. The light-induced redox transitions of the photosystem I reaction center P700 were measured by the intensity of the EPR signal I produced by P700+. Both forms of ferredoxin, Fd I and Fd II, when added to the chloroplasts in catalytic amounts, stimulate the light-induced electron transfer from P700 to NADP+. Nevertheless, Fd I is a better mediator of the back reactions from NADPH to P700+. This electron transfer pathway is sensitive to the cyclic electron transport inhibitor, antimycin A, and to DCMU inhibitor of electron transport between photosystem II and plastoquinone. It may be concluded that the two molecular forms of ferredoxin, Fd I and Fd II, differ in their ability to catalyze cyclic electron transport in photosystem I. The role of Fd I and Fd II in regulation of electron transport at the acceptor site of photosystem I is discussed.     

Olive Phenolics as c-Met Inhibitors: (-)-Oleocanthal Attenuates Cell Proliferation,Invasiveness, and Tumor Growth in Breast Cancer Models

Dysregulation of the Hepatocyte growth factor (HGF)/c-Met signaling axis upregulates diverse tumor cell functions, including cell proliferation, survival, scattering and motility, epithelial-to-mesenchymal transition (EMT), angiogenesis, invasion, and metastasis. (-)-Oleocanthal is a naturally occurring secoiridoid from extra-virgin olive oil, which showed antiproliferative and antimigratory activity against different cancer cell lines. The aim of this study was to characterize the intracellular mechanisms involved in mediating the anticancer effects of (-)-oleocanthal treatment and the potential involvement of c-Met receptor signaling components in breast cancer. Results showed that (-)-oleocanthal inhibits the growth of human breast cancer cell lines MDA-MB-231, MCF-7 and BT-474 while similar treatment doses were found to have no effect on normal human MCF10A cell growth. In addition, (-)-oleocanthal treatment caused a dose-dependent inhibition of HGF-induced cell migration, invasion and G1/S cell cycle progression in breast cancer cell lines. Moreover, (-)-oleocanthal treatment effects were found to be mediated via inhibition of HGF-induced c-Met activation and its downstream mitogenic signaling pathways. This growth inhibitory effect is associated with blockade of EMT and reduction in cellular motility. Further results from in vivo studies showed that (-)-oleocanthal treatment suppressed tumor cell growth in an orthotopic model of breast cancer in athymic nude mice. Collectively, the findings of this study suggest that (-)-oleocanthal is a promising dietary supplement lead with potential for therapeutic use to control malignancies with aberrant c-Met activity.     

Microbial decomposition of 3,4-dichloroaniline, adsorbed by activated charcoal]

The accessibility of 3,4-dichloroaniline (DCA) sorbed by activated carbon to degradative microorganisms was studied. A Paracoccus denitrificans strain capable of growing on medium with DCA as the only source of energy, carbon, and nitrogen was used in the experiment. The high sorption capacity of all the carbons studied (powdered RS and SKT-6A and granular AG-3) in relation to DCA (350 to 360, 480 to 520, and 540 to 580 mg/g, respectively) was demonstrated. The sorption capacity correlated positively with the specific surface area and the total volume of the sorbent micropores. The bulk of the DCA was reversibly sorbed and amenable to microbial decomposition; however, the decomposition rates significantly differed. When RS, SKT, and Agrosorb preliminarily saturated with DCA were incubated in a culture of P. denitrificans, the bulk of the reversibly sorbed DCA was decomposed (in the absence of the other carbon sources) in 2, 5, and 10 weeks, respectively, after which the process slowed down. At the end of the experiment (29 weeks), 81 to 87% of the DCA underwent full mineralization, which was accompanied by the release of chlorine ions; a small fraction of the xenobiotic (0.8 to 1.9%) remained a reversibly sorbed fraction (extractable with acetone), and 12 to 17% of the initial DCA seemed to have been chemically transformed and bound by carbon. The studied carbons may be used in biological decontamination of chloroaniline-polluted soils to decrease the toxic effect of chloroanilines on microorganisms.     

Peculiarities of digestive function of proteinases in invertebrates—Inhabitants of cold seas

Digestive proteinases of various taxa of invertebrates of the boreal seas have been studied: crustaceans Paralithodes camtchaticus, Pandalus borealis; molluscs Chlamys islandicus, Buccinum undatum, Serripes groenlandicus, and echinoderms Strongylocentrotus droebachiensis, Cucumaria frondosa, Asterias rubens, and Crossaster papposus. The presence of two proteolytic activity peaks in the acidic (pH 2.5–3.5) and lower alkaline ranges (pH 7.5–8.5) and a similar proteinase spectrum have been revealed in digestive organs of the studied animals. The proteolytic activity in digestive organs of the Barents Sea invertebrates exceeds significantly that of terrestrial homoiothermal animals, which seems to be an extensive compensation for poor differentiation of the digestive system and for low substrate specificity of the enzymes as well as for cold conditions of the habitat. The principal qualitative difference between vertebrates and invertebrates consists in that the latter have no pepsin activity, but do have the cathepsin activity that is absent in vertebrate digestive organs. Contribution to the acid proteolysis is made by lysosomal cathepsins, rather than by pepsins. Activity in the alkaline and neutral pH ranges is provided by serine proteinases. In digestive cavities of invertebrates, hydrolysis of proteins and mechanical processing of food occur only in the lower alkaline pH range, whereas acid proteolysis has intracellular lysosomal localization.     

Properties of chitinolytic enzymes from the hepatopancreas of the red king crab (Paralithodes camtschaticus)

Our study confirms the presence of chitinolytic, chitosanolytic, and deacetylase activities in the hepatopancreas of the red king crab, related to the specific diet of this species. The maximum rate of chitin/chitosan hydrolysis by an enzyme preparation from crab hepatopancreas occurs at 36.5-37.0 degrees C. Two pH optimums have been found for the enzymatic reaction under mildly alkaline and acidic conditions for both exo- and endochitinase activities. The enzyme preparation is most affine to partly deacetylated chitin with an acetylation degree within 40-50%.     

Properties of chitinolytic enzymes from the hepatopancreas of the red king crab (<Emphasis Type="Italic">Paralithodes camtschaticus</Emphasis>)

Our study confirms the presence of chitinolytic, chitosanolytic, and deacetylase activities in the hepatopancreas of the red king crab, related to the specific diet of this species. The maximum rate of chitin/chitosan hydrolysis by an enzyme preparation from crab hepatopancreas occurs at 36.5–37.0°C. Two pH optimums have been found for the enzymatic reaction under mildly alkaline and acidic conditions for both exo-and endochitinase activities. The enzyme preparation is most affine to partly deacetylated chitin with an acetylation degree within 40–50%.     

NIDA522131, a new radioligand for imaging extrathalamic nicotinic acetylcholine receptors: in vitro and in vivo evaluation

A novel radioligand, 6-chloro-3-((2-( S )-azetidinyl)methoxy)-5-(2-fluoropyridin-4-yl)pyridine (NIDA522131), for imaging extrathalamic nicotinic acetylcholine receptors (nAChRs) was characterized in vitro and in vivo using positron emission tomography. The K_d and T_1/2 of dissociation of NIDA522131 binding measured at 37°C in vitro were 4.9 ± 0.4 pmol/L and 81 ± 5 min, respectively. The patterns of radioactivity distribution in monkey brain in vivo was similar to that of 2-[¹⁸F]fluoro-3-(2( S )-azetidinylmethoxy)pyridine (2FA), a radioligand that has been successfully used in humans, and matched the α₄β₂* nAChRs distribution. Comparison between [¹⁸F]NIDA522131 and 2FA demonstrated better in vivo binding properties of the new radioligand and substantially greater radioactivity accumulation in brain. Consistent with [¹⁸F]NIDA522131 elevated affinity for nAChRs and its increased lipophilicity, both, the total and non-displaceable distribution volumes were substantially higher than those of 2FA. Estimated binding potential values in different brain regions, characterizing the specificity of receptor binding, were 3–4 fold higher for [¹⁸F]NIDA522131 than those of 2FA. Pharmacological evaluation in mice demonstrated a toxicity that was comparable to 2FA and is in agreement with a 2300 fold higher affinity at α₄β₂* versus α₃β₄* nAChRs. These results suggest that [¹⁸F]NIDA522131 is a promising positron emission tomography radioligand for studying extrathalamic nAChR in humans.     

Proteolysis in vitro as the Way of Modification of the Protein Trophic Component

The protein hydrolysates of two types, fodder and for microbiological medium, have been obtained in vitro, using protein containing wastes of Iceland scallop fishery (WSF) and enzyme preparation from the red king crab hepatopancreas. The degree of protein degradation and composition of obtained hydrolysates were analyzed. Intensive protein hydrolysis was necessary to obtain the microbiological diagnostic cultural media that fit trophic requirements for 12 microbial test-cultures. Addition of the fodder protein hydrolysate to diet of juvenile salmons Salmo salar during mixed feeding produces a positive effect on their survival; the 5 and 20% replacement of fish flour by the fodder hydrolysate results in a reduction of fish mortality by 21 and 57%, respectively. The living weight of chickens increased by 15% after substitution of the 10% fish flour by the fodder WSF hydrolysate in their diet. The results obtained can be explained by a more effective assimilation of partly hydrolyzed proteins in comparison with native ones.