Comparative karyological analysis of five species of viviparus (gastropoda: prosobranchia)

Karyological analysis was performed on Viviparus ater (Cristofori & Jan, 1832), V. acerosus Bourguignat, 1862, V. mamillatus (Kuster), V. viviparus (Linnaeus, 1758) and V. contectus (Millet, 1813), collected from different freshwater bodies of Switzerland, Hungary, Albania, Italy and Lithuania. The karyotypes of V. acerosus and V. mamillatus are described for the first time. The diploid number of chromosomes in V. contectus equals 14, whereas in diploid sets of other studied species, 18 chromosomes are present. The karyotype formula is in V. contectus (5m + 2sm, NF = 28, in V. ater, 7m + 1sm-m + 1 sm, in V. acerosus and V. viviparus, 8m + 1sm, NF = 36, in V. mamillatus, 6m + 1m-sm + 1sm-m + 1sm, NF = 36. In females of V. ater, V. mamillatus and V. acerosus, the heteromorphism of chromosome pair no. 8 was observed, with a sex-determining mechanism — ZW female /ZZ male. Although, Z and W chromosomes are metacentric, significant differences (P > 0.05, or P > 0.001) in their size were determined. The interspecific significant differences (P > 0.05) in karyotypes of V. ater, V. mamillatus, V. acerosus and V. viviparus were detected by using one-way ANOVA and Bonferroni¹s Multiple Comparison tests. Only chromosomes of the pair no. 5 were of similar shape in all of these species. The smallest interspecific difference was between V. viviparus and V. acerosus. The intraspecific karyological differences in relative chromosome length and centromeric index of V. contectus from lakes Garda (Italy), Olauka and Asveja (Lithuania) were observed in the chromosome pair no.

COMPARATIVE KARYOLOGICAL ANALYSIS OF FIVE SPECIES OF VIVIPARUS (GASTROPODA: PROSOBRANCHIA)

Karyological analysis was performed on Viviparus ater (Cristofori & Jan, 1832), V. acerosus Bourguignat, 1862, V. mamillatus (Kuster), V. viviparus (Linnaeus, 1758) and V. contectus (Millet, 1813), collected from different freshwater bodies of Switzerland, Hungary, Albania, Italy and Lithuania. The karyotypes of V. acerosus and V. mamillatus are described for the first time. The diploid number of chromosomes in V. contectus equals 14, whereas in diploid sets of other studied species, 18 chromosomes are present. The karyotype formula is in V. contectus (5m + 2sm, NF = 28, in V. ater, 7m + 1sm-m + 1 sm, in V. acerosus and V. viviparus, 8m + 1sm, NF = 36, in V. mamillatus, 6m + 1m-sm + 1sm-m + 1sm, NF = 36. In females of V. ater, V. mamillatus and V. acerosus, the heteromorphism of chromosome pair no. 8 was observed, with a sex-determining mechanism — ZW female /ZZ male. Although, Z and W chromosomes are metacentric, significant differences (P > 0.05, or P > 0.001) in their size were determined. The interspecific significant differences (P > 0.05) in karyotypes of V. ater, V. mamillatus, V. acerosus and V. viviparus were detected by using one-way ANOVA and Bonferroni¹s Multiple Comparison tests. Only chromosomes of the pair no. 5 were of similar shape in all of these species. The smallest interspecific difference was between V. viviparus and V. acerosus. The intraspecific karyological differences in relative chromosome length and centromeric index of V. contectus from lakes Garda (Italy), Olauka and Asveja (Lithuania) were observed in the chromosome pair no.

Genotoxicity and histological alterations in grey mullet mugil liza exposed to petroleum water-soluble fraction (PWSF)

Petroleum hydrocarbons are considered one of the main organic chemicals found in water bodies. In the present study, the median lethal concentration (LC50) was estimated for mullet Mugil liza after acute exposure to petroleum watersoluble fraction (PWSF). Furthermore, histopathological studies and micronuclei frequency were also performed in order to observe deleterious effects of medium-term exposition to PWSF. Mullets (25±2.3 g) were exposed to chronic concentrations (1.7, 3.5 and 7 % of PWSF), plus the control group, for 14 and 7 days of clearance time. Throughout the experimental period (1, 4, 14 and 21 days), blood samples were collected for analysis of micronucleus (MN) and liver and gills for histopathological study. For these procedures, seven fish were sampled per concentration tested. The LC50-96 h was estimated at 37.5 % of the PWSF. The time required for MN induction was 96 h of exposure. The time of clearance was sufficient to achieve a MN frequency similar to that of the control group. Histopathological studies showed severe changes in the gill and liver tissues. The most relevant histopathology in the gills was telangiectasia. Hepatic histopathology such as cholestasis, dilated sinusoids and inflammatory infiltrates were commonly described. The MN test and histological study effectively detected damages caused by medium-term exposition to the PWSF, and despite the toxicity, a few days without exposure can minimize PWSF genotoxicity in juveniles of M. liza Remove selecte