Erythroid progenitor cells from pig bone marrow and peripheral blood

With the intention of using the pig as a large animal model in haematopoietic research, a clonal assay in methylcellulose was developed and the optimal conditions for raising erythroid progenitors from adult pig bone marrow (BM) and peripheral blood (PB) have been established. Progenitor cells were stimulated to proliferate and differentiate in vitro by growth factors containing leucocyte condition medium (LCM), and with recombinant human erythropoietin (rhEpo). The number of PB BFU-E (burst forming units - erythroid) directly depended on the concentration of LCM, but BM BFU-E were not dependent on LCM. Both CFU-E (colony forming units - erythroid) and BFU-E were rhEpo dependent. Despite relatively high but expected individual variations, the mean number of colonies, as well as the functional characteristics of progenitor cells investigated, were similar to those of miniature pigs and some other mammals.     

Evidence for genetic diversity of Toxoplasma gondii in selected intermediate hosts in Serbia

To contribute to the insight into the worldwide population structure of Toxoplasma gondii, we genetically characterized a total of eight strains isolated from intermediate hosts including humans, sheep and pigeons in Serbia. Although parasite DNA was detected in 28.2% (60/213) of the human samples from 162 patients serologically suspected of active toxoplasmosis, as well as in 5/7 seropositive pigeons and in 2/12 seropositive sheep examined, multilocus PCR-RFLP genotyping, using SAG1, 5′SAG2, 3′SAG2, GRA6, 5′GRA7 and 3′GRA7 as markers, was successful in only four human isolates (of which one was isolated from both the bronchoalveolar lavage fluid and blood samples of a single patient), one sheep and three pigeons. Of the eight isolates, five were type II (62.5%), one was type III, one was atypical, and one had a type I allele at GRA6 as the single locus genotyped. Although type II, as elsewhere in Europe, predominated, these results may suggest a higher genetic diversity of T. gondii in Serbia, reflecting local environmental contamination and also the geographical position of the country in South-East Europe.     

In vitro antimicrobial susceptibility of 183 Pseudomonas aeruginosa strains isolated from dogs to selected antipseudomonal agents

During the years from 1993 to 2000, 183 strains of Pseudomonas aeruginosa were isolated from different pathological specimens originating from dogs. Antimicrobial susceptibility patterns against 10 antipseudomonal agents were obtained on 183 P. aeruginosa strains. In vitro antimicrobial susceptibility testing was performed using the disk diffusion method (Kirby-Bauer). Antimicrobial susceptibility profiles showed that among beta-lactam antibiotics, imipenem was the most active compound. Out of the 183 strains tested, 96.7% were sensitive to imipenem. Cefoperazone showed good in vitro activity against 86.9% of the tested strains. Against ceftazidime, 77.0% of strains showed sensitivity. An old penicillin, carbenicillin, gave only 71.6% sensitive strains. Sensitivity to amikacin was 87.4% and it was 83.1% to gentamicin. Pipimedic acid, a first-generation quinolone, was the least active compound of all those tested, 47.0% were resistant. The in vitro sensitivity against enrofloxacin showed that 71.0% strains were sensitive and 26.2% showed resistance. Almost all strains tested, 93.4%, were susceptible to ciprofloxacin and marbofloxacin. Besides imipenem, the quinolone antibiotics, marbofloxacin and ciprofloxacin were the most effective against P. aeruginosa strains isolated from dogs.     

Sequence analysis of both genome segments of three Croatian infectious bursal disease field viruses

In order to determine the mutations responsible for virulence, three Croatian field infectious bursal disease viruses (IBDV), designated Cro-Ig/02, Cro-Po/00, and Cro-Pa/98 were characterized. Coding regions of both genomic segments were sequenced, and the nucleotide and deduced amino acid sequences were compared with previously reported full-length sequenced IBDV strains. Phylogenetic analysis, based on the nucleotide and deduced amino acid sequences of polyprotein and VP1, was performed. Eight characteristic amino acid residues, that were common to very virulent (vv) IBDV, were detected on polyprotein: 222A, 256I, 294I, 451L, 685N, 715S, 751D, and 1005A. All eight were found in Cro-Ig/02 and Cro-Po/00. C-Pa/98 had all the characteristics of an attenuated strain, except for glutamine on residue 253, which is common for vv, classical virulent, and variant strains. Between less virulent and vvIBDV, three substitutions were found on VP5: 49 G --> R, 79 --> F, and 137 R --> W. In VP1, there were nine characteristic amino acid residues common to vvwIBDV: 146D, 147N, 242E, 390M, 393D, 511S, 562P, 687P, and 695R. All nine residues were found in A-Ig/02, and eight were found in B-Po/00, which had isoleucine on residue 390. Based on our analyses, isolates Cro-Ig/02 and Cro-Po/00 were classified with vv IBDV strains. C-Pa/98 shared all characteristic amino acid residues with attenuated and classical virulence strains, so it was classified with those.     

Plant Accumulation of Natural Radionuclides as Affected by Substrate Contaminated with Uranium-Mill Tailings

Environmental concern due to plant accumulation of natural radionuclides is a major concern in uranium mining areas. To evaluate the risk associated with the transfer of radionuclides to edible plants, the uptake of ²³⁸U, ²²⁶Ra, and ²¹⁰Pb by Chinese cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) grown in soils contaminated with uranium-mill tailings (UMT) was investigated. Test plants were grown under controlled conditions in substrate composed of soil and UMT in different ratios. Activity concentrations of ²³⁸U, ²²⁶Ra, and ²¹⁰Pb in substrate, leaves, and roots were measured and the concentration ratios determined. Soil characteristics were determined, since they directly affect bioavailability of radionuclides. Concentration ratios of ²³⁸U, ²²⁶Ra, and ²¹⁰Pb in leaves varied from 0.001 to 0.006, 0.024 to 0.172, and 0.004 to 0.011, respectively, and in roots from 0.020 to 0.126, 0.015 to 0.241, and 0.033 to 1.460, respectively. Concentrations of ²³⁸U, ²²⁶Ra, and ²¹⁰Pb in leaves and roots were found to correlate with the amount of ²³⁸U, ²²⁶Ra, and ²¹⁰Pb in the substrate. A higher amount of ²²⁶Ra accumulated in aboveground parts (57–877 Bq kg^?1 d. m. for leaves) compared to ²³⁸U (0.6–4.7 Bq kg^?1 d. m. for leaves) and ²¹⁰Pb (8–53 Bq kg^?1 d. m. for leaves), which were mainly stored in the roots. The relationships between the amount of radionuclides in plants and soil characteristics and their role in radionuclide uptake are discussed and critically evaluated.     

Vergleichende Untersuchung von Phosphorwasserstoff entwickelnden Präpapaten zur Getreidebegasung

Zusammenfassung Die Ergebnisse der hier dargestellten Versuche zeigen, sowohl bezüglich der Verteilung des Phosphorwasserstoffes im Getreide als auch bezüglich der Wirksamkeit der PH₃-Präparate auf die Abtötung der Schädlinge, eindeutig, daß die Art der Verteilung der Präparate eine wesentliche Rolle für den Begasungserfolg spielt. Hierbei stellt das Gewicht der Präparate (Pellet, Tablette, Beutel) einen entscheidenden Faktor für ihre Verteilung im Getreide und damit für den Erfolg der Begasung dar.Selbstverständlich ist auch das Präparat in Beutelform brauchbar für die Begasung von Schä dlingen in gelagertem Getreide. Der Hauptunterschied zwischen dem Beutel und der Tablette bzw. dem Pellet in der praktischen Anwendung besteht aber darin, daß Tablette und Pellet durch ihre gleichmäßigere Verteilung eine bessere Wirksamkeit m der Abtötung der Schädlinge bei gleichzeitig geringerer Dosierung pro Tonne Getreide besitzt.Bei der Getreidebegasung spielen schließlich auch ökonomische Gesichtspunkte eine Rolle.Es kann also der Schluß gezogen werden, daß Präparate in Papierbeuteln für die Getreidebegasung weder anwendungstechnische noch ökonomische Vorteile gegenüber dem bei uns bisher bekannten Tabletten- bzw. Pellet-Präparat besitzt.Auf Grund der Ergebnisse dieser Versuche wie auch der bisher gemachten Erfahrung bei der Anwendung von PH₃-Präparaten in der Getreidebegasung kann gesagt werden, daß Präparate wie Tabletten und Pellets für unsere Bedingungen sowohl hinsichtlich der Wirksamkeit gegenüber Getreideschädlingen wie auch in ökonomischer Hinsicht ausgezeichnet verwendbar sind.

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Summary Referring to the distribution of hydrogen phosphide in grain as well as to the effectiveness of the PH₃ preparations for the destruction of insect pests, the results of the herein described tests show clearly that the method of distribution of the preparations plays an essential part for the success of the fumigation. Hereby the weight of the preparations (pellet, tablet, bag) is a decisive factor for their distribution in grain and therefore also for the succes of the fumigation.Naturally, the preparation in bags is also usable for the fumigation of insect pests in stored grain. The main difference between bag and tablet, respectively pellet, in the practical application lies, however, in the fact that tablet and pellet, due to their more uniform distribution, are more effective for the destruction of insect pests allowing at the same time a reduced dosage rate per ton of grain. Last but not least, economical aspects represent an important factor in grain fumigation.It, therefore, can be concluded that reparations in paper bags have no advantages in grain fumigation, as far as technique of application and economy are concerned, when compared with the tablet and pellet preparations so far known in this country.Based on the results of these tests and on the experience gained in application of PH₃ preparations in grain fumigation, one can say that preparations like tablets and pellets are most suitable under our conditions as far as efficacy against grain insect pests and economical aspects are concerned.

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Karadjordjeva 17 (Jugoslawien)     

Relationships between line per se and testcross performance for agronomic traits in two broad-based populations of maize

Degree of the association between line per se performance (LP) and testcross performance (TP) is important in breeding programs and simultaneous improvement of commercial hybrids and their parental lines. This experiment was designed to study genetic variability and genetic correlation for several agronomic traits in two maize (Zea mays L.) broad-based populations (NS12-SG and NS14-SG). Independent trials with 80 entries of S₁ progenies as well as their testcrosses were arranged according to an incomplete block design with replicates in sets. Grain yield, stay green, anthesis-silking interval, stalk water content and grain moisture were evaluated in four environments. The anthesis-silking interval had the highest genetic variation, followed by stay green. High heritability estimates (>0.50) for all traits, pointed out that further selection would be possible. Genetic correlations between line per se and testcross performance were lowest for grain yield (0.396** and 0.592**, for NS12-SG and NS14-SG, respectively), and highest for grain moisture (0.937** and 0.821**, respectively). High correlations between line per se and their testcrosses for stay green, anthesis-silking interval, stalk water content and grain moisture indicated that additive gene action might be more important than dominance in controlling the expression of these traits.