PROCEEDINGS OF THE LATVIAN ACADEMY OF SCIENCES

SECTION B: NATURAL, EXACT AND APPLIED SCIENCES
(ISSN 1407-009X, Language: English)

Volume 50 (1996) Number 3
SPECIALIZED ISSUE: BIOLOGICAL SCIENCES


Original Paper: Biochemistry

EFFECT OF CADMIUM ON EGG PRODUCTION, AND Cd DISRTRIBUTION IN EGGS AND TISSUES OF HENS

Viktorija Baumane, Mudite Valiniece, and Dmitrijs Babarikins*
Institute of Biology, Latvian Academy of Sciences, Miera iela 3, Salaspils, LV-2169 LATVIA
* Medical Academy of Latvia, Dzirciema iela 16, Riga LV-1007 LATVIA

Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 97-102. Language: English.

Abstract: In an acute experiment on laying hens, the effect of Cd was studied on egg production, calcification of eggshell and distribution of Cd in hen tissues and various parts of egg. After Cd administration, a fast swelling of the ovariole was observed. Hens of the control group laid eggs almost every day; but hens receiving 5 mg Cd per day during a ten day period and hens receiving a single dose of 50 mg Cd, each laid only 2-4 eggs during the ten day period.
A gradual fall in shell mass was observed, and the last eggs laid had no shell at all. At dissection, atrophy of ovaries was observed. The highest levels of Cd were found in organs and tissues of hens fed a single dose of 50 mg Cd. In liver and kidneys, the level of Cd reached 13-15 mg/g ash, however it was minimal (0.130-0.028 mg/g) in muscles and cannon bone (tibia). A considerable amount of Cd, 0.276 mg/g, had accumulated in feathers. The same amount (50 mg) of Cd when administered in portions, lowered the level of Cd in tissues by 2-3 times. In egg, the highest level of Cd (0.068 mg/g) was found in the shell membrane and the lowest (0.014-0.019 mg/g), in the white. In egg yolk, the initial level was 0.025 mg/g Cd with a drastic increase to 0.054 mg/g Cd in the eggs laid last. The eggshell had a constant level, 0.030 mg/g, of Cd. Cadmium toxicosis in hens was accompanied by disturbed Ca metabolism and depressed biosynthesis of calcium-binding protein in uterus.
Key words: Cd, Ca, laying hens, eggs.


Original Paper: Biochemistry

BIOLOGICAL PROPERTIES OF HYBRID RECOMBINANTS OF BREAM AND STURGEON GONADOTROPINS

Henriks Zenkevics, Vita Slanke, and Vija Vose
Institute of Biology, Latvian Academy of Sciences, Miera iela 3, Salaspils, LV-2169 LATVIA
Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 103-107. Language: English.

Abstract: Two active hybrid heterodimers, alpha(s) + beta(b) and alpha(b) + beta(s), were created by cross-recombination of gonadotropic hormone (GTH) subunits from systematically distant fish, sturgeon (s) and bream (b). Double immunodiffusion showed that the hybrids had lost their antigenic specificity and, unlike native preparations, they cross-reacted with each other's antisera.
The hybrids had similar immunoreactivity with sturgeon GTH antiserum, while the activity with bream GTH antiserum depended on beta subunit species specificity. Rather high gonadotropic activity was found in alpha(s) + beta(b), observed in tests on frog oocytes. The recombinant alpha(b) + beta(s) exhibited low hormonal function.
It was shown that the functional domains of hybrid alpha - beta heterodimers were formed by both subunits, but hormonal specificity depended mainly on the included beta subunit.
Key words: gonadotropic hormone, subunits, hybrid recombinants, immunoreactivity, gonadotropic activity.


Original Paper: Pharmacology

THE EFFECTS OF GLUTAPYRONE, A GLUTAMATE-CONTAINING 1,4-DIHYDROPYRIDINE COMPOUND, ON THE CARDIOVASCULAR SYSTEM, MUSCLE CONTRACTION, AND PROTEIN KINASE C ACTIVATION

Vija Klusa, Rasma Vitolina, Maija Dambrova, Zeltite Atare, Rudolfs Mezapuke, Dainuvite Meirena, Egils Bisenieks, Gunars Duburs, and Angelo Azzi*
Latvian Institute of Organic Synthesis, Aizkraukles iela 21, Riga, LV-1006 LATVIA
*Institute of Biochemistry and Molecular Biology, University of Bern, Buhlstrasse 28, Bern 9 CH-3000, SWITZERLAND

Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 108-113. Language: English.

Abstract: The influence of glutapyrone, a glutamate-containing 1,4-dihydropyridine (DHP) derivative [disodium salt of 2-(2,6-dimethyl-3,5-diethoxycarbonyl-1,4-dihydropyridine-4-carboxamido)-glutaric acid] on blood pressure, heart rate and respiration was studied at doses of 0.1-100.0 mg/kg in anaesthetized cats and rabbits. In in vitro experiments, the effects of glutapyrone on norepinephrine-induced contraction of isolated rabbit aorta, and on 45Ca uptake in rabbit myocardial slices were tested. At high doses (10.0-100.0 mg/kg i.v.), glutapyrone induced a bi-phasic dose-dependent effect on blood pressure: a short (8-18 s) and slight (5-20 mmHg) depressor response and more prolonged (11 min) pressor response (5-15 mmHg) in anaesthetized rabbits. In cats, only the highest dose tested (100 mg/kg) exerted the pressor-depressor effects (changes of about 20 mmHg), which lasted for 1 min. The haemodynamic changes were accompanied by some respiratory stimulation in both animal species; no influence on heart rate was observed. In isolated rabbit aorta, glutapyrone, at concentration of 10 micromols, induced a long-lasting increase in norepinephrine-evoked contraction, not only in the presence of glutapyrone, but also 1 h after its washout. The norepinephrine-evoked contractile effect in isolated aorta was also enhanced in the presence, but not absence, of the well-known calcium agonist BAYk 8644. Glutapyrone did not change the contraction force of isolated spontaneously beating rabbit atria, nor change the 45Ca uptake in rabbit myocardial slices. The obtained data suggest that glutapyrone lacks the calcium antagonist properties, that are typical for the traditional 1,4-dihydropyridines (DHPs). The replacement of the phenyl group by glutamate in position 4 of the DHP ring, may transform the pharmacological properties of the DHP into a new category. The ability of glutapyrone to intensify the phorbol-activated protein kinase C activity in the cultured aortic smooth muscle cells (A7r5 line) suggests that glutapyrone acts via activation of intracellular events, presumably those that are G-protein-mediated.
Key words: glutapyrone, glutamate-containing 1,4-dihydropyridine, cardiovascular effects, smooth muscle contraction, protein kinase C.


Original Paper: Microbiology

BEHAVIOUR OF POLY-beta-HYDROXYBUTYRATE-BASED BIOPOLYMER FILMS IN DIFFERENT MEDIA

Ludmila Savenkova, Tamara Filatova*, Veronika Bubovica**, Jevgenijs Zagreba, Zoja Gercberga, Vaira Saulite**, and Dace Strode*
Institute of Microbiology and Biotechnology, University of Latvia: Kronvalda bulv. 4, Riga, LV-1586 LATVIA
*Institute of Inorganic Chemistry: Miera iela 34, Salaspils, LV-2169 LATVIA
**A. Kirhensteins Institute of Microbiology and Virology, A. Kirhensteina iela 1, Riga, LV-1067 LATVIA

Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 114-118. Language: English.

Abstract: Poly-beta-hydroxybutyrate (PHB) has been shown to be a biopolymer with potential use in macromolecular therapeutic systems, since it is compatible with mammalian cells. PHB was microbiologically synthesized at the Institute of Microbiology, using the strain Azotobacter 23. An aim of this work was to determine the specific properties of this biodestructive polymer in various conditions in vivo and in vitro.
Key words: biopolymers, poly-beta-hydroxybutyrate, biodestructive properties, implantation.


Original Paper: Immunology

IMMUNOMODULATING PROPERTIES OF ISOPRINOSINE ANALOGUES

Juris Maurins, Margeris Lidaka, Ruta Paegle, Larisa Poluektova*, Nadezda Gromova*, Zanna Graudina*, and Arturs Socnevs*
Latvian Institute of Organic Synthesis, Aizkraukles iela 21, Riga, LV-1006 LATVIA
*Medical Academy of Latvia, Dzirciema iela 16, Riga, LV-1007 LATVIA

Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 119-125. Language: English.

Abstract: Preliminary studies of two immunopharmacological profile of the new immunomodulating agents, the isoprinosine analogues OSI-3649 and OSI-1220, were performed in mice in vivo and in human lymphocytes from peripheral blood in vitro. OSI-1220, a complex of 7-(beta-D-glucofuranuronosyl)hypoxanthine and N,N- dimethylaminopropanol-2-p-acetaminobenzoate, and OSI-3649, a complex of 7-(beta-D-ribofuranosyl)hypoxanthine and N,N-dimethylaminopropanol-2-p-acetaminobenzoate, both compounds in 1:3 molar ratio, were used. Single p.o. doses of the new compounds, given with the antigen, increased the number of antibody producing cells in spleen and decreased the delayed hypersensitivity reaction to SRBC. OSI-3649 increased the humoral immune response to HBsAg after 3 times administration before immunisation. OSI-1220 did not stimulate Fc-dependent phagocytosis, and OSI-3649 suppressed phagocytosis and ink clearance 24 h after administration. However, OSI-1220 suppressed activity of NK cells in high concentration and stimulated its activity, similarly to isoprinosine at a concentration of 10 micrograms/ml in vitro. These data suggest that modification of the purine nucleoside structure causes significant changes of the properties of the new compounds, in comparison with isoprinosine, and induces development of immunosuppression. OSI-3649 stimulated the PFC formation and anti-HBs antibody production, similarly to isoprinosine, but had no influence on phagocytosis and decreased DTH reaction. OSI-1220 affected PFC formation and induced short-term stimulation at a low dose, to the same extent as isoprinosine, but later, OSI-1220 depressed the function of peritoneal macrophages.
Key words: immunomodulating agents, isoprinosine analogues, phagocytosis, activity of NK cells, antibody production.


Original Paper: Genetic Toxicology

THE RECOMBINOGENIC AND MUTAGENIC INFLUENCE OF FORMALDEHYDE ON YEAST Saccharomyces cerevisiae CULTURES

Simona Toma and Jekabs Raipulis
Institute of Microbiology and Biotechnology, University of Latvia, Kronvalda bulv. 4, Riga, LV-1586 LATVIA
Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 126-129. Language: English.

Abstract: The effects of formaldehyde on the viability and conversion frequency of yeast Saccharomyces cerevisiae ade2 gene heteroallelic diploids, and the number of respiratory-deficient mutants were investigated. An increase of conversion frequency was observed already at a concentration of 1 microgram/ml. A formaldehyde concentration of 30 micrograms/ml increased the rate of spontaneous conversion frequency by 20 times. The number of respiratory-deficient mutants increased with increase of formaldehyde concentration, and at a concentration of 30 micrograms/ml, it was 19 times higher than in the control. These changes were observed in sublethal concentrations.
Key words: Formaldehyde, Saccharomyces cerevisiae, conversion frequency, respiratory deficiency.


Original Paper: Biotechnology

APPLE JUICE FERMENTATION BY LIQUID AND DRY INSTANT WINE YEASTS

Lilija Auzina, Ramona Kruce, Dagnija Upite, and Martins Bekers
Institute of Microbiology and Biotechnology, University of Latvia, Kronvalda bulv. 4, Riga, LV-1586 LATVIA
Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 130-132. Language: English.

Abstract: Commercial dry wine yeast (the Danish "Uvaferm CEG") was tested for apple juice fermentation and compared with the liquid wine yeast used at the "Riga" wine factory. Fermentation of apple juice using the dry yeast was intensive, and high alcohol-dehydrogenase activity was observed. Another active dry wine yeast, from a culture obtained from the Institute of Microbiology and Biotechnology, University of Latvia, is produced commercially by "Rigas raugs". High ethanol and sugar resistance of this culture has been demonstrated. Therefore, we recommend dry wine yeast for development of high-quality fruit-and/or-berry wine production in Latvia.
Key words: wine yeast, apple juice, fermentation activity, yeast cultures.


Original Paper: Biotechnology

DRY LACTATE CONCENTRATE: PHYSICAL AND CHEMICAL PROPERTIES AND BIOTECHNOLOGY

Lija Dukalska, Anita Blija, and Liga Skudra
Faculty of Food Technology, Latvian University of Agriculture, Liela iela 2, Jelgava, LV 3001, LATVIA
Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 133-136. Language: English.

Abstract:A curd whey was used to produce a dry lactate concentrate. The total protein amount in the process of fermentation was increased by addition of 25 % NH4OH non-protein nitrogen. The fermented ammoniated whey was concentrated to 40 % of the dry solids (DS), and concentrated fermented ammoniated whey (CFAW) was obtained. The dynamics of density, kinematic viscosity, titrated acid content and environmental pH were observed. To obtain dry lactate concentrate, which is a skimmed milk substitute, the CFAW was neutralizated by Ca(OH)2. Optimal parameters for this process were: CFAW content of the dry substance was 40 %, temperature was 50 oC, and the rotation speed of mixers was 49.5 cycles/min. The most important rheological features were investigated.
Key words: whey, biotechnology, titrated acid, pH, rheological features, fodder.


Original Paper: Biotechnology of Ethanol

SUITABILITY OF SOME SORTS OF GRAIN FOR ETHANOL FERMENTATION IN LATVIA

Janis Laukevics, Martins Bekers, Aleksejs Danilevics, Ellena Kaminska, Arija Lisovska, Dagnija Upite, and Armands Vigants
Institute of Microbiology and Biotechnology, University of Latvia, Kronvalda bulv. 4, LV-1586, Riga, LATVIA
Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 137-139. Language: English.

Abstract: The economy of ethanol production depends on the quality and price of the raw material and the technology used. The technological characteristics of Latvian local grain were determined. The efficiency of Novo Nordisk commercial enzymes for liquefaction and saccharification of mash was tested for some grain crops in Latvia. Laboratory ethanol fermentations and some techological criteria indicated that triticale and wheat are at present the more suitable grains for ethanol fermentation in Latvia' s agronomic conditions.
Key words: barley, rye, triticale, wheat, ethanol, enzymes, fermentation.


Original Paper: Biotechnology

A METHOD OF PURIFICATION AND CHARACTERISTICS OF Zymomonas mobilis 113 s levan

Raimonds Linde, Svetlana Gonta, Aerna Karsakevica, Ilmara Vina, and Martins Bekers
Institute of Microbiology and Biotechnology, University of Latvia, Kronvalda bulv. 4, LV-1586, Riga, LATVIA
Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 140-143. Language: English.

Abstract:A method has been worked out to obtain highly purified Zymomonas mobilis 113 s levan, by its release from endotoxins. The method is based on the precipitation of levan in alkaline medium (pH 12.0) by ethanol.
Analysis by gel-chromatography showed that purified levan contains several fractions (3-2000 kDa), among which approx. 75 % are high-molecular-mass fractions. The obtained results will be used to develop the technology for production of pharmacologically active high-molecular-mass levan by using fractionated precipitation by ethanol.
Key words: polysaccharides, levan, endotoxins, non-specific immunostimulator, precipitation by ethanol, molecular mass.


Original Paper: Microbiology/Biotechnology

INFLUENCE OF WATER ACTIVITY AND MEDIUM OSMOLALITY ON THE GROWTH AND ACID PRODUCTION OF Lactobacillus casei var. alactosus

Mara Marauska, Armands Vigants, Anna Klincare, Dagnija Upite, Ellena Kaminska, and Martins Bekers
Institute of Microbiology and Biotechnology, University of Latvia, Kronvalda bulv. 4, LV-1586, Riga, LATVIA
Proc. Latvian Acad. Sci., Section B (LATVIA, ISSN: 1407-009X), Vol. 50 (1996), No. 3, pp. 144-146. Language: English.

Abstract: A new Lactobacillus casei var. alactosus strain was isolated and investigated ar the Institute of Microbiology and Biotechnology, University of Latvia. High resistance of this strain to osmotic gradients generated by NaCl and sorbitol was demonstrated in experiments. Water activity (aw) properties were determined. The data obtained show, that this Lactobacillus strain can be used in lactic-acid fermentation of salt-containing food products.
Key words: Lactobacillus, lactic acid, water activity, osmolality, food products.


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