Volume 46 (2000) No. 2

Volume 46 (2000) No. 2

Articles
Immunolocalization of the Boar Seminal Immunosuppressive Fraction Infused Via Uterus
on the Lymphocytes Populating Mouse Genital Tract Tissues
J. DOSTÁL¹, B. ŽELEZNÁ², V. JONÁKOVÁ², L. VESELSKÝ²................................59
¹Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Liběchov, Czech Republic
²Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
Corresponding author: Leopold Veselský, Institute of Molecular Genetics, Academy of Sciences
of the Czech Republic, Flemingovo nám. 2, 166 37 Prague 6, Czech Republic. Tel: (+) 420 2 20183414;
Fax: (+) 420 2 24310955.
Abstract.
Full text pp. 59-61 62-63 64 65 66-68

Melatonin and Retinyl Acetate as Chemopreventives in DMBA-induced Mammary Carcinogenesis in Female Sprague-Dawley Rats
E. AHLERSOVA, I. AHLERS, P. KUBATKA, B. BOJKOVA, K. MOCIKOVA, Š. GAJDOSOVA, H. M. ONDERKOVA................................................................69
Institute of Animal Physiology, Faculty of Science, P.J. Šafárik University, Košice, Slovakia
Corresponding author: Eva Ahlersová, Institute of Animal Physiology, Faculty of Science, P. J. Šafárik University, Moyzesova 11, 041 67, Košice, Slovakia.
Abstract.
Full text pp. 69-72

Effects of Retinyl Acetate and Melatonin on N-methyl-N-nitrosourea-induced
Mammary Carcinogenesis in Rats. A Preliminary Report.
B. BOJKOVÁ, P. KUBATKA, K. MÔCIKOVÁ, M. MNÍCHOVÁ, E. AHLERSOVÁ,
I. AHLERS..........................................................73
Institute of Animal Physiology, Faculty of Science, P. J. Šafárik University, Košice, Slovakia
Corresponding author: Eva Ahlersová, Institute of Animal Physiology, Faculty of Science, P. J .Šafárik University, Moyzesova 11, 041 67 Košice, Slovakia.
Abstract.
Full text pp. 73-76

Role of Melanotransferrin (p97) in Non-transferrin Iron Uptake by HeLa and K562 Cells
K. KRIEGERBECKOVÁ, J. KOVÁŘ............................77
Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
Corresponding author: Jan Kovář, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4, Czech Republic. Tel. 420 (2) 475 2637; Fax 420 (2) 44 47 17 07; e-mail: kovarbiomed.cas.cz.
Abstract.
Full text pp. 77-81

Short Communication
Preimplantation Development of Giant Triploid Zygotes in the Mouse
L. KÁRNÍKOVÁ¹, P. JACQUET², J. FULKA, Jr.¹...............................83
1Institute of Animal Production, Prague, Czech Republic
2Laboratory of Radiobiology, Belgium Nuclear Research Centre (SCK/CEN), Mol, Belgium
Corresponding author: Lenka Kárníková, The Institute of Animal Production, POB1, CS-10401 Prague 10, Czech Republic. Tel: + 420 (2) 67710659; Fax: + 420 (2) 677710779; e-mail: karnikova@vuzv.cz.
Abstract.
Full text pp. 83-84 85-86

Monoclonal Antibodies Register
New Monoclonal Antibodies Specific for Microtubule-associated Protein MAP2
M. ZÍKOVÁ, E. DRÁBEROVÁ, V. SULIMENKO, P. DRÁBER....................87
Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
Corresponding author: Pavel Dráber, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Vídeňská 1083, 142 20 Prague 4, Czech Republic. Fax: 420 (2) 475 2758; e-mail:paveldra@biomed.cas.cz.
Background.
Full text pp. 87-88

Monoclonal Antibodies Against Type-A Staphylococcal Enterotoxin
B. HOLEČKOVÁ, J. GONDOĽ, V. KALINÁČOVÁ, M. FOTTA......................89
Department of Bacteriology and Hybridoma Technology, Research Institute of Veterinary Medicine, Košice, Slovakia
Corresponding author: Beáta Holečková, Department of Bacteriology and Hybridoma Technology, Research Institute of Veterinary Medicine, Hlinkova 1/A, 040 01 Košice, Slovakia.
Background.
Full text pp. 89-90

Intrauterine deposition of the immunosuppressive fraction from boar seminal vesicle fluid (ISF) led to a supression of antibody response to soluble and corpuscular antigens in mice. By means of an immunofluorescent method using specific monoclonal antibody, ISF was detected on the membranes of white blood cells and splenocytes of mice subjected to intrauterine treatment from the third day to the thirteenth day after its deposition. ISF was also detected on the lymphocytes populating the mucosal tissues of vagina, cervix, oviduct and uterus from day 1 to 13 after its intrauterine administration. The antibody to soluble and corpuscular antigens was inhibited in the mice treated with ISF, but after the cessation of the ISF application, a normal immune response was restored within 40 days. Sandwich immunosorbent assay revealed that intrauterine infusion of ISF decreased significantly the concentration of IgG and IgM in the sera of immunized mice both after the primary and the secondary immunizations. These findings indicate that the intrauterine infusion of semen may influence the immune defense reactions and may be an important factor in the development of viral and bacterial infections of the female reproductive tract.
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Melatonin and Retinyl Acetate as Chemopreventives in DMBA-induced Mammary Carcinogenesis in Female Sprague-Dawley Rats
E. AHLERSOVA, I. AHLERS, P. KUBATKA, B. BOJKOVA, K. MOCIKOVA, Š. GAJDOSOVA, H. M. ONDERKOVAOne goal of experimental oncology is to find and test effective chemopreventive substances which can suppress malignant transformation of the cells, their cumulation and invasion. Mammary gland tumours were induced by DMBA applied intragastrically (10 mg/rat, three times) every three days between postnatal days 50 and 60 in female Sprague-Dawley rats. One day after the last dose we started chemoprevention with Mel, RA and combination of both drugs, which lasted 25 weeks. Mel was drunk continuously as a solution in tap water (100 mikrog/ml). RA was applied daily in the dose of 8.2 mg/rat per os. There were four experimental groups: 1. control - no chemoprevention, 2. Mel treatment, 3. RA treatment, 4. application RA+Mel. At the end of the experiment the incidence, frequency, latency and average volume of tumours were evaluated. In the group treated with Mel tumour incidence, latency and volume did not differ from controls; the frequency of tumours was decreased. Treatment with RA and with combination RA+Mel decreased mammary tumour incidence to 38% (RA) and 48% (RA+Mel); it also decreased frequency and prolonged latency. Thus chemoprotective effects of RA and combination of RA with Mel were proved in mammary carcinogenesis induced by DMBA. The oncostatic effect of Mel alone was not confirmed. In our previous paper (Bojková et al., 2000) drinking of lower doses of Mel during the late afternoon and night prolonged the latency period and in combination with RA showed an oncostatic effect on mammary carcinogenesis induced by NMU. Further studies are needed to elucidate the conditions of successful chemoprevention with Mel.
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The aim of this project was to evaluate the effect of retinyl acetate (RA), melatonin (Mel) and their combination on N-methyl-N-nitrosourea (NMU)-induced rat mammary carcinogenesis. Female Sprague-Dawley rats were given two intraperitoneal doses of NMU, each of 50 mg/kg of b.w. between 43th to 57th postnatal day. The administration of RA started 11 days and the administration of Mel 12 days before the first dose of NMU. RA was given daily in a dose of 8.2 mg per animal and day per os. Mel was given as a solution (20 mikrog/ml of tap water) between 1500 and 0800, from 0800 to 1500 the animals were drinking tap water only. The experiment was finished 22 weeks after the first administration of the carcinogen. The tumour incidence in the control group was 88%, in the group treated with RA 80% and in the group treated with Mel 61%. A substantial decrease in tumour incidence to 37% was noted in the group treated with RA plus Mel. Significant differences in incidence were noted in the group treated with the combination of RA and Mel as compared to the control group with RA administration. Chemoprevention lenghtened the latency significantly in the group treated with Mel and with the combination of RA and Mel. The decrease in tumour frequency per group was confirmed in the group treated with the combination of RA and Mel; differences between groups in the frequency per tumour-bearing animal were not observed. The volume of mammary tumours in the groups treated with chemopreventive agents was not changed.
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Role of Melanotransferrin (p97) in Non-transferrin Iron Uptake by HeLa and K562 Cells
K. KRIEGERBECKOVÁ, J. KOVÁŘ

We tested whether melanotransferrin (p97), an iron-binding protein of the plasma membrane, is involved
in the transport of non-transferrin iron into human HeLa and K562 cells. The expression of melanotransferrin was detected in HeLa but not in K562 cells. PI-PLC treatment dramatically decreased (to 20% of the original value) p97 expression by HeLa cells. However, the rate of iron uptake from ⁵⁵Fe-ferric citrate by PI-PLC-treated HeLa cells was comparable or only slightly lower (80-100%) than the rate of iron uptake by untreated cells. PI-PLC treatment had no effect on iron uptake by K562 cells. These findings strongly support a suggestion that melanotransferrin does not play a substantial role in non-transferrin iron uptake by either HeLa or K562 cells.
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Short Communication
Preimplantation Development of Giant Triploid Zygotes in the Mouse
L. KÁRNÍKOVÁ, P. JACQUET, J. FULKA, Jr.

Giant oocytes or two-cell embryos have been reported in various mammalian species. They may arise during multiplication of oogonia, after fusion of two oogonia or, more probably, when nuclear division is not accompanied by cytoplasmic division. The ultimate fate of these giant embryos is not well known. In our laboratory, giant two-cell mouse embryos have been occasionally observed. One of them was cultured and reached the blastocyst stage at the same time as normal embryos. Recently, we also observed two giant one-cell zygotes in the same species. Both showed two female pronuclei and one male pronucleus, as well as two second polar bodies localized at opposite poles of the embryo. These two giant zygotes also showed normal viability and developmental capacity. Their triploid nature was confirmed by cytogenetic analysis. In order to study this interesting phenomenon in more detail, we produced giant oocytes containing two germinal vesicles by cell fusion and cultured them in vitro. About one third of them extruded two first polar bodies; in the second group only one polar body was observed, whilst the last group was without polar bodies. When parthenogenetically activated, the consistent answer analogical to that observed in "in vivo" oocytes was only observed when oocytes with two polar bodies were activated. The implication for IVF technologies is discussed.
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Monoclonal Antibodies Register
New Monoclonal Antibodies Specific for Microtubule-associated Protein MAP2
M. ZÍKOVÁ, E. DRÁBEROVÁ, V. SULIMENKO, P. DRÁBER

The microtubule-associated protein 2 (MAP2) is an abundant neuronal cytoskeletal protein that binds to tubulin and stabilizes microtubules (Herzog and Weber, 1978). MAP2 is essential for the development and maitenance of neuronal morphology (Matus, 1991). In neurons MAP2 occurs as three primary isoforms, the high molecular weight MAP2a, MAP2b, and the low molecular weight MAP2c, that result from alternative splicing of the MAP2 gene (Chung et al., 1996). The low molecular weight isoform, MAP2c, is expressed in developing brain and is down-regulated during brain maturation, whereas the high molecular weight MAP2b is expressed in both developing and adult brain. The MAP2a appears only after brain maturation (Tucker, 1990). All these forms bind to microtubules through a domain near its carboxyl terminus that contains either three or four similar repeats of a 31-amino-acid motif (Lewis et al., 1988). MAP2 together with MAP4 and tau proteins belong to the family of thermostable proteins associated with microtubules.
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Monoclonal Antibodies Against Type-A Staphylococcal Enterotoxin
B. HOLEČKOVÁ, J. GONDOĽ, V. KALINÁČOVÁ, M. FOTTA

Type A staphylococcal enterotoxin (SEA) is a single-chain, heat-stable protein with a molecular
weight of 27.8 kDa and isoelectric point (pI) of 7.3 (Su and Wong, 1997), which is produced by enterotoxigenic strains of Staphylococcus aureus. SEA, along with staphylococcal enterotoxins B and C (SEB and SEC), belong to enterotoxins most frequently occuring in foodstuffs. By its ability to form complexes with molecules of the MHC class II and subsequently to activate a large number of T lymphocytes, it falls into the group of superantigens (Svensson et al., 1997). Due to the proliferation of a large proportion of T lymphocytes, an excessive quantity of lymphokines is released that are likely to contribute to the development of enterotoxin-induced disease - staphylococcal enterotoxicosis (Marrack and Kappler, 1990). Relatively little is known of antigenic determinants of staphylococcal enterotoxins and how these may relate to the structure and function of the toxins (Wood, et al., 1997). To detect staphylococcal enterotoxins in foodstuffs, immunochemical methods (RIA, ELISA) are mostly employed using specific polyclonal and monoclonal antibodies. Monoclonal antibodies against SEA were prepared
to be usedin the development of the ELISA method.
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