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PubMed2006

[The migration and differentiation of subventricular zone neural stem cells transplanted into the adult striatum].

Adeno-associated virus vectors (type2) containing the marker gene--green fluorescent protein (AAV2-GFP) were used to transduce subventricular zone neural stem cells (NSCs). NSCs labelled by gene product--GFP were transplanted into adult Sprague-Dawley rat striatum. The animals were allowed to survive for 45 days, 90 days and 120 days before they were perfused. All the fixed brains were serially sectioned in the saggital plane,at the sickness of 30 microm with a cryostat microtome. These results showed that, at all stages, GFP labelled NSCs were seen in the injection sites,and a lot of them dispersed in the host brains. GFP labelled NSCs showed directional migration 45 days following transplantation. 120 days after transplantation, a group of GFP labelled NSCs migrated dorsally and posteriorly, reached corpus callosum; another group of transplanted NSCs migrated ventrally and posteriorly,reached substantia nigra, moreover,a number of these cells migrated through or over the substantia nigra and reached the more ventral boundary of the substantia nigra. The migrating NSCs were in chains, GFP labelled cells in substantia nigra were beta-tubulin III immunoreactive.

Animals↗
PubMed1990

CD38 molecule: structural and biochemical analysis on human T lymphocytes, thymocytes, and plasma cells.

The structure of the CD38 molecule has been evaluated by one- and two-dimensional gel analysis and by enzymatic digestions. The source of the Ag was mainly membrane preparations obtained from MLC cells, from normal thymocytes, and from the plasmocytoma line LP-1. Membranes were solubilized in NP-40 and the extracts fractionated by immunoaffinity chromatography [using a specific anti-CD38 antibody (A10 mAb) covalently linked to Sepharose protein A]. The purified Ag migrated as a single chain of Mr = 45,000 not associated with beta 2-microglobulin. Two-dimensional IEF gel electrophoresis revealed five spots (isoelectric point (pI) range: 6.5 to 6.9). After neuraminidase treatment, the mobility of the five polypeptides shifted to a more basic pI. Endoglycosidase-H treatment reduced the Mr of CD38 by 20%, revealing a broader band centered at Mr = 36,000. Treatment of CD38 molecule with V8 Staphylococcus aureus protease yielded a single dominant band at Mr = 38,000 which was still reactive with A10 mAb. The CD38 molecular was trypsin-resistant in both denatured or native conditions. These results clearly show the glycoprotein nature of CD38 molecule, which includes 2 to 4 N-linked oligosaccharide chains containing sialic acid residues. Furthermore, the present data indicate that the CD38 molecule does not display an apparent biochemical polymorphism among the different CD38+ cells or lines.

ADP-ribosyl Cyclase↗
PubMed1990

[Monitoring the tritium content in waste waters and objects in the surroundings of Soviet nuclear power plants].

As illustrated by experimental data on Rovenskaya atomic power plant (APP) the sources of tritium release into environment have been assessed. The studies show that about 70% of tritium vaporize through cooling towers and the remaining quantity is discharged into the Styr river. In the nearest future it becomes necessary to study tritium discharge from APP equipped with reactors of various types in more detail and analyze its migration path in food chains. Thus it will be possible to specify the contribution of this nuclide into the dose load on the population living near APP. It is demonstrated that under existing levels of tritium content in environment objects (up to 5 Bq/l) it can be quite accurately measured by means of modern sensitive scintillators without preliminary separation.

Food Contamination, Radioactive↗
PubMed1985

Human erythrocyte clathrin and clathrin-uncoating protein.

Clathrin, a Mr = 72,000 clathrin-associated protein, and myosin were purified in milligram quantities from the same erythrocyte hemolysate fraction. Erythrocyte clathrin closely resembled brain clathrin in several respects: (a) both are triskelions as visualized by electron microscopy with arms 40 nm in length with globular ends and a flexible hinge region in the middle of each arm, and these triskelions assemble into polyhedral "cages" at appropriate pH and ionic strength; (b) both molecules contain heavy chains of Mr = 170,000 that are indistinguishable by two-dimensional maps of 125I-labeled peptides; and (c) both molecules contain light chains of Mr approximately 40,000 in a 1:1 molar ratio with the heavy chain. Erythrocyte clathrin is not identical to brain clathrin since antibody raised against the erythrocyte protein reacts better with erythrocyte clathrin than with brain clathrin and since brain clathrin contains two light chains resolved on sodium dodecyl sulfate gels while the light chain of erythrocyte clathrin migrates as a single band. The erythrocyte Mr = 72,000 clathrin-associated protein is closely related to a protein in brain that mediates ATP-dependent disassembly of clathrin from coated vesicles and binds tightly to clathrin triskelions (Schlossman, D. M., Schmid, S. L., Braell, W. A., and Rothman, J. E. (1984) J. Cell Biol. 99, 723-733). The erythrocyte and brain proteins have identical Mr on sodium dodecyl sulfate gels and identical maps of 125I-labeled peptides, share antigenic sites, and bind tightly to ATP immobilized on agarose. Clathrin and the uncoating protein are not restricted to reticulocytes since equivalent amounts of these proteins are present in whole erythrocyte populations and reticulocyte-depleted erythrocytes. Clathrin is present at 6,000 triskelions/cells, while the uncoating protein is in substantial excess at 250,000 copies/cell.

Carrier Proteins↗
PubMed1983

Epidermal growth factor-like transforming growth factor. I. Isolation, chemical characterization, and potentiation by other transforming factors from feline sarcoma virus-transformed rat cells.

An acid-stable transforming growth factor (TGF) that interacts with epidermal growth factor (EGF) receptors and is structurally related to EGF was isolated from serum-free culture fluids of Snyder-Theilen feline sarcoma virus-transformed rat embryo (FeSV-Fre) cells. Purification of this EGF-like TGF (eTGF) was achieved by molecular filtration chromatography and successive reverse-phase high pressure liquid chromatography steps on octadecyl support eluted with acetonitrile and 1-propanol gradients, respectively. Rat eTGF consists of a 7.4-kD single polypeptide chain that co-migrates with biological activity in dodecyl sulfate-polyacrylamide electrophoresis gels. Like preparations of a related TGF from human melanoma cells (Marquardt, H., and Todaro, G.J. (1982) J. Biol. Chem. 257, 5220-5225), but unlike EGF from rat, human, or mouse, rat eTGF has phenylalanine and lacks methionine. However, the sequence of the first 30 amino acid residues in rat eTGF is H2N-Val-Val-Ser-His-Phe-Asn-Lys-Cys-Pro-Asp-Ser-His-Thr-Gln-Tyr-Cys-Phe-His-Gly - Thr-(x)-Arg-Phe-Leu-Val-Gln-Glu-Glu-(Lys)-(Lys)-, which is significantly (20% and 28%) homologous to the NH2-terminal region of mouse EGF and human EGF, respectively. In addition to eTGF, molecular filtration chromatography of acid-soluble extracts from medium conditioned by FeSV-Fre cells resolved a 14-kD transforming factor(s) apparently devoid of intrinsic mitogenic activity but able to elicit a strong anchorage-independent growth response in the presence of eTGF or EGF. These results show that: 1) a 7.4-kDa TGF structurally and functionally related to EGF has been isolated from FeSV-Fre cells and 2) the full anchorage-independent growth-promoting activity of medium conditioned by FeSV-Fre cells is due to the coordinate action of at least two types of factors, the 7.4-kDa eTGF and a second 14-kDa transforming factor(s).

Amino Acid Sequence↗
PubMed1994

Fibrinogen Milano V: a congenital dysfibrinogenaemia with a gamma 275 Arg-->Cys substitution.

An abnormal fibrinogen was discovered in a clinically asymptomatic woman from Italy. Routine coagulation studies revealed prolonged thrombin and reptilase clotting times and a discrepancy between the plasma fibrinogen levels determined by the clotting assay and electroimmunoassay. Release of fibrinopeptides A and B from fibrinogen Milano V by thrombin was normal. Fibrin polymerization was strongly delayed in the presence of EDTA and was partially corrected at physiological calcium concentration. Normal migration of mercaptolysed polypeptide chains was observed in polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. Moreover, there was no apparent abnormality in the charge of the reduced chains of the variant fibrinogen, as judged by two-dimensional gel electrophoresis. A fragment of the gamma-chain gene coding for the amino acids 259-350 was amplified and cloned. The amino acid gamma 275 arginine was found to be substituted by cysteine. Immunoblotting analysis with a rabbit antiserum against human serum albumin indicated that albumin was not linked to the odd sulphydryl group of fibrinogen Milano V. Treatment of fibrinogen Milano V with cysteamine, that is surmised to convert the mutant cysteine to a positively charged lysine analogue, did not improve the clotting properties of fibrinogen Milano V.

Afibrinogenemia↗
PubMed1993

Single-strand conformational polymorphism analysis of the M(r) 170,000 isozyme of DNA topoisomerase II in human tumor cells.

Five cell lines selected for resistance to the cytotoxicity of inhibitors of DNA topoisomerase II have point mutations in the gene that codes for the M(r) 170,000 form of this enzyme. In each case, the mutation results in an amino acid change in or near an ATP binding sequence of the M(r) 170,000 isozyme of topoisomerase II. We used single-strand conformational polymorphism analysis to screen for similar mutations in other drug-resistant cell lines or in leukemic cells from patients previously treated with etoposide or teniposide. We also analyzed the region of the gene that codes for amino acids adjacent to the tyrosine at position 804 of topoisomerase II which binds covalently to DNA. CEM/VM-1, CEM/VM-1-5, and HL-60/AMSA human leukemic cell lines were used as controls; 3 of 3 known mutations were detected by migration differences of polymerase chain reaction products from the RNA extracted from these three lines. A previously unknown mutation was found in the tyrosine 804 region of the M(r) 170,000 topoisomerase II expressed by CEM/VM-1 and CEM/VM-1-5 cells. Sequence analysis showed that substitution of a T for a C at nucleotide 2404 resulted in an amino acid change of a serine for a proline at amino acid 802. No mutations in any of the ATP binding sequences or in the tyrosine 804 region were detected in polymerase chain reaction products from RNA extracted from human leukemia HL-60/MX2 or CEM/MX1 cells (both cell lines selected for resistance to mitoxantrone) or in human myeloma 8226/Dox1V cells (selected for resistance by simultaneous exposure to doxorubicin and verapamil). No mutations were detected in polymerase chain reaction products from RNA extracted from blasts of 15 patients with relapsed acute lymphocytic leukemia, previously treated with etoposide or teniposide. We conclude that: (a) single-strand conformational polymorphism analysis is useful for screening for mutations in topoisomerase II; (b) resistance to the cytotoxicity of inhibitors of DNA topoisomerase II is not always associated with mutations in ATP binding sequences or the active site tyrosine region of M(r) 170,000 topoisomerase II; and (c) mutations similar to those detected in drug resistant cells selected in culture have not been identified in blast cells from patients with relapsed acute lymphocytic leukemia, previously treated with etoposide or teniposide.

Adenosine Triphosphate↗
PubMedDate not supplied

[A decade after Chernobyl: the results of research on radioecology].

The paper presents the general results from the 10-year (1986-1996) studies on radioecology and radiobiology conducted in the region affected by radiation after the accident at the Chernobyl NPP. The regularities of radionuclide migration along the trophic chains, as well as effect of ionising radiation on biota in its habitat are described. The protective measures are reported aimed at mitigating consequences of the accident for the environment. The paper also presents the main findings of studies on agricultural radioecology with taking into account the importance of radionuclide turnover in agrosphere and implementation of countermeasures in the agro-industrial production.

Agriculture↗
PubMed1996

[Role of host behavior in the life cycle of parasites].

Parasite is an organism which, at least in a part of its ontogeny uses another living organism as a proper environment for its life. In the "parasite-host" relationships, formed by both these components, the parasite itself bears the burden of formation and maintenance of these relationships in a balance. Three factors play the main role in this process: (1) physiological adaptations of the parasite, enabling survival in the host body and resistance against defence reactions of the host; (2) morphological adaptations, leading to changes in the body structure of the parasite, dependent on location in the host body; and (3) behavioural adaptations assuring contacts of parasites with their hosts. In the process of evolution most groups of parasites evolved a complicated life cycle, with change of host and outer environment, succeeding in maturation of the parasite and production of the offspring. To pursuit this aim the parasite takes advantage from the behaviour of its potential host, its food preferences (e.g. by inclusion into a food chain), periodic or circadian migrations, and generally from its mode of life. The parasite modifies behaviour of its hosts, sometimes to a high degree, especially the behaviour of intermediate hosts, making them more conspicuously displayed for predators, the most often their final hosts. The parasite itself changes also its behaviour to be more attractive for a potential host or to enhance the possibility of finding a proper host. Finally, in a host population the parasite bears upon the position of particular host individuals by degradation of dominants and shifting them from reproduction. This phenomenon may be considered as a self-defence of the host population against reproduction of ill individuals, weaken by a burden of parasites.

Animals↗
PubMed1975

Type III procollagen and collagen in skin.

A form of collagen, containing three alpha chains of type III, can be extracted from foetal calf, calf and rat skin under physiological conditions. This native collagen was purified by DEAE-cellulose chromatography and then was analysed by polyacrylamide gel electrophoresis which showed it consisted of several high molecular weight components, the size of gamma components and larger species. Prior reduction in dithiothreitol dissociated these large polymers into two components: the minor one migrated between the alpha1 (I) and alpha2 chains while the predominant one migrated between the alpha and beta chains. These two monomers were isolated by CM-cellulose chromatography. The minor one, which eluted between the alpha1 and alpha2 chains, had a molecular weight of approx. 95 000; its amino acid composition was similar to that of alpha1(III). The major one eluted in the alpha1 region and had a molecular weight of approx. 120 000; its amino acid composition, while similar to that of the alpha1(III) chain, differed in detail, and it is presumed to be a pro-alpha1(III) chain. Following pepsin digestion, the native collagen remained as a disulfide-bonded trimer which dissociated into only one component, a1(III), when denatured in dithiothreitol. These results suggest that the original, extracted protein consisted primarily ofa precursor form of type III collagen. This procollagen did not polymerize when heated at 37 degrees C and did not form the usual segment long spacing aggregates under suitable conditions. It was not modified by incubation with a purified procollagen peptidase preparation. This appears to be the first example of the isolation of type III (pro)collagen by extractive methods, without resorting to tissue digestion by proteolytic enzymes.

Amino Acids↗
PubMed2004

Regulation of biological activity of laminin-5 by proteolytic processing of gamma2 chain.

Laminin-5 (LN5), which regulates both cell adhesion and cell migration, undergoes specific extracellular proteolytic processing at an amino-terminal region of the gamma2 chain as well as at a carboxyl-terminal region of the alpha3 chain. To clarify the biological effect of the gamma2 chain processing, we prepared a human recombinant LN5 with the 150-kDa, non-processed gamma2 chain (GAA-LN5) and natural LN5 with the 105-kDa, processed gamma2 chain (Nat-LN5). Comparison of their biological activities demonstrated that GAA-LN5 had an about five-times higher cell adhesion activity but an about two-times lower cell migration activity than Nat-LN5. This implies that the proteolytic processing of LN5 gamma2 chain converts the LN5 from the cell adhesion type to the cell migration type. It was also found that human gastric carcinoma cells expressing the LN5 with the non-processed gamma2 chain is more adherent but less migratory than the carcinoma cells expressing a mixture of LN5 forms with the processed gamma2 chain and with the unprocessed one. The functional change of LN5 by the proteolytic processing of the gamma2 chain may contribute to elevated cell migration under some pathological conditions such as wound healing and tumor invasion.

Adenocarcinoma↗
PubMed1985

Studies on globin chain synthesis during hamster development.

Erythroid cells derived from the yolk-sac of the hamster embryos replicate in the embryonic circulation, actively synthesize hemoglobin, and are the dominant circulating erythroid cell through day 14 of gestation. Until day 11, at which time fetal liver rudiments appear, they are the only erythroid tissue present in the embryo. Because of their size (Fig. 1 and Table 1) they can be separated from erythrocytes produced by ontogenically later hemopoietic tissue (liver, spleen, bone marrow). The embryonic (three) and adult (three) globin chains of hamster hemoglobins separate cleanly by electrophoresis in polyacrylamide gel, (Fig. 2). This provides an advantage over mouse, whose x and z chains tend to co-migrate. During hamster embryonic development, yolk-sac erythroid cells first become available on day 7. Nine days later (birth), globin-chain ontogeny in the circulating blood is nearly complete (Fig. 3). When yolk-sac-derived erythroid cells are isolated at day 10 in gestation (prior to the appearance of fetal liver) and grown in culture for 3 days, changes in types of globin chains synthesized are identical to globin-chain ontogenic changes in vivo during gestational days 10 through 13 (Fig. 5). We conclude that the ontogenic "switch" of globin-gene expression in these erythroid cells is pre-programmed, and that the program is capable of full function despite a drastic change in cell environment from circulating blood to culture medium. The ability to study these primitive erythroid cells under the tightly controllable conditions of culture might facilitate acquisition of information on mechanisms of globin-gene ontogeny.

Animals↗
PubMedDate not supplied

[Migration of n-alkanes from diesel oil along the bacteria-ciliates trophic chain].

The data on the dynamics of the content and qualitative composition of intracellular alkanes in Paramecium caudatum Ehrenberg, 1838 cells feeding on bacteria with different levels of exposure to diesel oil are presented. The possibility of migration of alkanes from diesel oil along the trophic chain from bacteria to ciliates was demonstrated.

Alkanes↗
PubMed1990

Electrophoretic separation and immunological identification of type 2X myosin heavy chain in rat skeletal muscle.

One slow and three fast myosin heavy chains have been described in typical skeletal muscles of the adult rat using immunocytochemical analysis. Electrophoretic isolation and immunochemical identification of these four isoforms has not been achieved. An electrophoretic procedure is described which, by altering the cross-linkage and polymerization kinetics of 5% polyacrylamide gels, allows resolution of these four distinct myosin heavy chains. Using specific monoclonal antibodies and double immunoblotting analysis, the identity and electrophoretic migration order of the myosin heavy chains was established to be: 2A less than 2X less than 2B less than beta/slow.

Animals↗
PubMed1984

Isolation and characterization of rabbit H of the alternative complement pathway.

Rabbit factor H, a control protein of the alternative complement pathway, was isolated from rabbit serum by polyethylene glycol precipitation, DEAE-Sephacel chromatography, and gel chromatography on Sephadex G200. The protein migrated as a single-chain polypeptide with a molecular weight of 160,000 on sodium dodecyl sulfate-gel electrophoresis with Laemmli's buffer system, but hardly migrated into the gel with Fairbanks' buffer system. Physical and chemical properties of rabbit H were similar to those of human H, except that fragments produced by limited tryptic digestion from rabbit H had different molecular sizes from those produced from human H. Significant species-specificity was observed in the functional activity of factor H; activation of the alternative complement pathway was inhibited more efficiently with homologous H than with heterologous H. In contrast, factor H inhibited the hemolysis of homologous erythrocytes less than that of heterologous erythrocytes.

Amino Acids↗
PubMed1997

Emergence of oligodendrocytes from human neural spheres.

To study the development of human oligodendrocyte precursors (OP), we expanded human embryonic brain-derived neural precursors into spheres with basic fibroblast growth factor (FGF2). Over 90% of the cells in the expanded spheres were precursors coexpressing nestin and the polysialylated (PSA) form of NCAM. The remaining cells were mostly astrocytes and neuronal cells located at the periphery of the floating spheres. When spheres were allowed to adhere on fibronectin-coated substrate in the absence of FGF2, neural precursors migrated in the outgrowth and often formed chains of cells expressing high levels of PSA-NCAM. Many migrating cells also expressed beta-3 tubulin while only scattered elongated cells radiating from the spheres were GFAP+ astrocytes. Spindle-shaped cells not associated with the chains were labeled for the PDGF-alpha receptor and often coexpressed MAP2 neuronal isoforms. Neuronal cells in the outgrowth rapidly established a rich neuritic network where OP expressing O4 and DM20/proteolipid antigens appeared. T3 treatment of neural spheres increased the rate of OP formation and the complexity of their shape. Thus, the generation of human oligodendrocytes from neural precursors is tightly correlated with growth of neuronal processes and enhanced by hormonal signals.

Brain↗
PubMedDate not supplied

Chemically modified tetracycline (CMT-8) and estrogen promote wound healing in ovariectomized rats: effects on matrix metalloproteinase-2, membrane type 1 matrix metalloproteinase, and laminin-5 gamma2-chain.

Estrogen deficiency is associated with impaired cutaneous wound healing. Remodeling of the extracellular matrix in wound healing involves the action of matrix metalloproteinases on basement membrane zone components, especially laminin-5. We studied the effects of estrogen and a potent matrix metalloproteinase inhibitor, chemically modified non-antimicrobial tetracycline, CMT-8, on wound healing in ovariectomized rats. At the tissue level, laminin-5 gamma2-chain expression was decreased and the migration-inductive 80 kDa form of laminin-5 gamma2-chain was absent in ovariectomized rats when compared with sham and CMT-8- or estrogen-treated ovariectomized animals as detected by Western blotting. The highest levels of gelatinolytic activity (matrix metalloproteinase-2 and -9) were found in sham animals. Levels were reduced in ovariectomized rats and were lowest after treating ovariectomized rats with CMT-8 or estrogen as analyzed by functional activity assay and zymography. The total amount of membrane type 1-matrix metalloproteinase was unchanged in all groups. We conclude that CMT-8 and estrogen can promote wound healing in ovariectomized rats, not only by normalizing wound bed total collagen content and structure, but also by recovering the expression and processing of key molecules in wound healing, i.e., laminin-5 gamma2-chain. This study shows, for the first time, the role of estrogen and CMT-8 in laminin-5 gamma2-chain modulation in vivo.

Animals↗