First record of the American cestode Proteocephalus ambloplitis (Leidy, 1887) (Proteocephalidae) in Europe.

Here, we report the first record of pleroceroids of the Nearctic tapeworm Proteocephalus ambloplitis (Leidy, 1887) in European fresh waters. The plerocercoids were found encapsulated in the internal organs of the invasive pumpkinseed Lepomis gibbosus (Linnaeus, 1758) in a pond in Bègles Plage, Bordeaux, France. This parasite species was not observed in L. gibbosus collected from two nearby localities, Bordeaux Lac and a pond in the Parc de Fontaudin. Species identification was confirmed using molecular data and morphological characteristics.

Onchocleidus principalis (Monogenea: Ancyrocephalidae) Co-introduced to Europe with Centrarchid Fish.

BACKGROUND: Non-native parasites are often translocated into novel areas together with their natural hosts, but the parasite diversity is frequently lower compared to the host's native range. PURPOSE: This paper provides morphological and molecular characterisation for non-native monogenean parasite Onchocleidus principalis (Ancyrocephalidae) co-introduced with its fish host to Portugal, Europe, including new details on the species' vaginal morphology and metrics. METHODS: Two host species, the largemouth bass Micropterus salmoides and pumpkinseed sunfish Lepomis gibbosus, were sampled from two reservoirs (Landeira, Coruche) in the Atlantic Sea drainage. Morphometric analysis and sequencing of 28S rDNA were performed. RESULTS: Presence of O. principalis was confirmed in all individuals of largemouth bass. Accidental findings on pumpkinseed sunfish at both sampling sites represent new host records for this parasite species. The morphometric description of O. principalis showed high similarity to the species in its native range. No intraspecific sequence variation of partial 28S rDNA was observed between specimens from the two sampling sites. Presence of another North-American ancyrocephalid parasite Onchocleidus dispar was confirmed in pumpkinseed sunfish at both sites, and in largemouth bass from the Coruche Reservoir, this representing the first record of O. dispar on largemouth bass in Europe. CONCLUSION: Onchocleidus principalis has been confirmed to parasitise both centrarchid fish species introduced to Europe. Compared to other studies, the species collected in Portugal exhibits pronounced vaginal armament.

Metazoan parasites of freshwater cyprinid fish ( Leuciscus cephalus): testing biogeographical hypotheses of species diversity.

The diversity and similarity of parasite communities is a result of many determinants widely considered in parasite ecology. In this study, the metazoan parasite communities of 15 chub populations (Leuciscus cephalus) were sampled across a wide geographical range. Three hypotheses of biogeographical gradients in species diversity were tested: (1) latitudinal gradient, (2) a 'favourable centre' versus 'local oasis' model, and (3) decay of similarity with distance. We found that the localities in marginal zones of chub distribution showed lower parasite species richness and diversity. A latitudinal gradient, with increasing abundance of larvae of Diplostomum species, was observed. There was a general trend for a negative relationship between relative prevalence or abundance and the distance from the locality with maximum prevalence or abundance for the majority of parasite species. However, statistical support for a 'favourable centre' model was found only for total abundance of Monogenea and for larvae of Diplostomum species. The phylogenetic relatedness of host populations inferred an important role when the 'favourable centre' model was tested. Testing of the hypothesis of 'decay of similarity with geographical distance' showed that phylogenetic distance was more important as a determinant of similarity in parasite communities than geographical distance between host populations.

Enhanced incorporation of thymidine into DNA in the liver of intact and partially hepatectomized rats pretreated with 5-azacytidine.

The administration of 5-azacytidine to rats resulted in enhancement of thymidine incorporation into liver DNA. Repeated doses of the drug caused a greater than 10-fold increase of thymidine incorporation. In 5-azacytidine-treated intact rats no changes in the activity of thymidine and thymidylate kinases were observed, whereas a marked depression of thymidine phosphorylase activity occurred. In intact animals the mitotic activity in the drug-treated livers changed slightly; however, 5-azacytidine administration before partial hepatectomy resulted in a dramatic increase of mitotic activity in 24-hr regenerating livers. In this case the observed increase in incorporation of thymidine was paralleled both by increased activity of thymidine and thymidylate kinases and by a decline in thymidine phosphorylase activity. The higher incorporation of radioactivity into liver DNA in intact rats pretreated with the drug can be accounted for, at least partially, by the lower cellular degradation of the injected radioactive thymidine used for labeling. In addition, alterations in the labeling and in the mitotic activity of hepatocytes and nonparenchymal cells caused by 5-azacytidine should be taken into consideration.

Stimulated DNA synthesis in livers and kidneys induced to proliferate associated with unchanged thymidine and thymidylate kinase activities.

Enhanced mitotic activity and stimulated DNA synthesis associated with unchanged activity of thymidine and thymidylate kinases were observed in mouse kidneys induced to proliferate by intracardiac injection of lead acetate, and in rat livers following repeated administration of 5-azacytidine. On the other hand, the enhanced thymidine kinase activity evoked by L-tryptophan given by intubation at later stages of liver regeneration was paralleled by the enhanced incorporation of thymidine into DNA only to a very small degree.

Liver growth, biosynthesis of cytidine nucleotides and level of cytochrome P-450 in rat liver after administration of alpha-hexachlorocyclohexane.

The biosynthesis of cytidine nucleotides and the level of microsomal cytochrome P-450 in intact and regenerating rat liver after repeated administration of alpha-hexachlorocyclohexane (alpha-HCH) were compared. In alpha-HCH treated animals the utilization of [2-14C] orotic acid for the synthesis of cytidine nucleotides is suppressed. In 24-h regenerating liver the incorporation of labelled orotic acid into cytidine nucleotides is markedly activated; the degree of activation is lower in regenerating livers of alpha-HCH treated animals. The changes in the level of cytochrome P-450 vary inversely with the changes in the utilization of [2-14C] orotic acid for the synthesis of cytidine nucleotides. The activity of cytidine triphosphate synthetase of liver cytosol increases shortly after the administration of alpha-HCH; uridine-cytidine kinase is enhanced in the later stages of the drug action. Within 15-45 min after the administration of alpha-HCH the uptake of [U-14 C] cytidine into the liver and its incorporation into RNA cytosine are increased. After the administration of the drug the uptake of [2-14 C] uridine and its incorporation into RNA uracil is also enhanced whereas its utilization for the synthesis of cytidine nucleotides of the acid-soluble extract as well as for the RNA cytosine are suppressed.

The chromosomes of L1210 mouse leukemia cells: G-banding, C-banding, and Ag-staining.

The karyotype of L1210 mouse leukemia cells was studied using G-banding, C-banding and Ag-staining methods. In modal chromosome number and G-banding patterns we were interested in the differences between line A and B carried by DBA/2 mice in our laboratory. Both lines had the modal chromosome number of 38. Lines differed significantly in the average number of nine chromosomes per karyotype, whereas in marker chromosomes significant difference was found only in M2 and M6. Marker M1 t(5, 12) was present in 95% of cells in line A and 100% of cells in line B. More than 50% of cells in both lines contained M2, M11, M13 and M14. X-Chromosome and chromosome No. 4 were most frequently absent. More than 80% of cells in both lines had only one chromosome No. 5, and trisomy of chromosome No. 15 was found in 50% of cells in line A and 40% in line B. Values for disomy were low for all chromosomes in both lines. Marker M1 t(5, 12) possessed C-banding material at the proximal end of translocated chromosome No. 5 and NOR at the proximal end of translocated chromosome No. 12. Marker M2 t(1, 12) without NOR had the C-banding material located at the proximal end of chromosome No. 1.

Karyotypes of the 5-azacytidine-sensitive and -resistant line of AKR mouse leukemia.

The karyotype of AKR mouse lymphoblastic leukemia cell line made resistant to 5-azacytidine was compared with the karyotype of parental line. In relation of 5-azacytidine-resistant line the parental cell have less chromosomes No. 5 and more of No. 17 per karyogram. The increased monosomy has been found in chromosomes No. 5, 6, 7, 8 and 18 in sensitive line and in chromosomes No. 1, 8 and 17 in 5-azacytidine-resistant cells. The highest occurrence of trisomy was present in the chromosomes No. 13 and 16 in both lines. In AKR sensitive cells 89% of karyograms displayed 3 to 13 markers per karyogram while in the resistant line there were only 37% of karyograms with 1 to 11 markers.

Enhanced mortality in offsprings of male mice treated with 5-azacytidine prior to mating. Morphological changes in testes.

5-Azacytidine administered to male mice prior to mating resulted in their decreased fertility and in the loss of offsprings at different periods of embryonic and postnatal development. The drug interfered with mature spermatozoa and spermatids; considerable distortion of cellular associations in seminiferous epithelium has been observed. The possible interaction of 5-azacytidine with the function and/or formation of microtubule protein is discussed.

The behaviour of NAD+ and NADH in Acinetobacter calcoaceticus during n-alkane assimilation.

The behaviour of the nicotinamide adenine dinucleotides NAD+ and NADH in Acinetobacter calcoaceticus during n-alkane assimilation was studied, acetate and succinate being used as reference carbon sources. The intracellular concentration of the two nucleotides was found to increase during the exponential growth phase, reaching its maximum in the phase of decreasing growth rates. In the exponential phase, the NAD+/NADH quotients were less than 1 and showed only unimportant variations. In the phase of decreasing growth rates, the concentration of NADH showed a distinct decrease, reaching its minimum in the stationary phase. Parallel to this, the concentration of NAD+ showed a continuous increase until the stationary phase was reached. This resulted in an increase, during the phase of decreasing growth rates, of the NAD+/NADH quotients to values greater than 1, similarly as recorded in the stationary phase. There were no fundamental differences in this behaviour between the individual carbon sources.