Fulvia Basaglia

Some aspects of isozymes of lactate dehydrogenase, malate dehydrogenase and glucosephosphate isomerase in fish

1. The present paper reports some aspects of the isozymes of LDH, MDH and GPI in fish. 2. In Petromyzontiformes LDH is encoded by a single Ldh-A gene locus. In Myxiniformes and in most vertebrates LDH is encoded by two gene loci, A and B. A third Ldh-C locus is characteristic of the bony fishes Actinopterygii. 3. In fish the MDH isozymes are generally encoded by three gene loci Mdh-M, Mdh-A and Mdh-B. 4. In most diploid bony fish the GPI is controlled by two independent gene loci Gpi-A and Gpi-B. 5. The relationships of isozymes with evolution of vertebrates, tissual specificity, ontogenetic changes, with physiological and metabolic roles are discussed.

Biochemical characteristics of red mullet of the central mediterranean

Abstract 1. 1. Electrophoretic and isoeletric focusing methods were utilized to differentiate the two red mullet species normally present in the Adriatic and central Mediterranean (Mullus barbatus and M. surmuletus). 2. 2. Several protein systems were studied: lactate dehydrogenase (LDH, EC 1.1.1.27), malate dehydrogenase (MDH, EC 1.1.1.37) and soluble lens proteins. 3. 3. Species-specific electrophoretic and isoelectrophoretic patterns were found in LDH and lens proteins, whereas the MDH of the two species exhibited the same pattern with both techniques. 4. 4. Of the protein systems analysed so far, LDH and lens proteins were found to be useful for our purposes: as they exhibit different patterns in the two species in question, they permit species identification even during the stages when this is impossible on morphological grounds. 5. 5. Some hypotheses for further study are put forward.

Interspecific gene differences and phylogeny of the sparidae family (perciformes, teleostei), estimated from electrophoretic data on enzymatic tissue-expression

Abstract 1. 1. ADH, PGM, GPI, G-3-PDH, G-6-PDH and SOD isozymes were analyzed in seven different tissues in 15 Sparidae species. 2. 2. Marked differences between species were found in tissue distribution of some of the different isozymes. SOD showed only three patterns of activity and is the enzyme with the least interspecific variation between species. 3. 3. The results are related to genetic, evolutionary and taxonomic factors. 4. 4. The phylogenetic tree for the 15 Sparidae species has been prepared on the basis of comparisons of the indexes of divergence. The Sparinae subfamily were found to be very heterogeneous. 5. 5. These studies indicate that some pairs of ever more distantly related species show no increase in their index of divergence. The species of the Pagellus genus reveal an unexpected taxonomic distance.

Isozyme distribution of ten enzymes and their loci in South American lungfish, Lepidosiren paradoxa (Osteichthyes, Dipnoi)

Scarce bibliographical data exists on the enzymes in Lepidosiren paradoxa and analysis of several enzymes was considered worthy of investigation. Distribution of ADH, ALP, FBALD, GAPDH, G3PDH, G6PDH, GPI, LDH, MDH, and PGM was identified in ten tissues (retina, heart, muscle, liver, kidney, lung, gut, gills, brain, and ovary) of the South American lungfish and compared with patterns previously described in other vertebrates. Compared with earlier results differences in the number of loci expressed were observed for ADH, G3PDH, GPI, and MDH. The number of loci expressed and/or in tissue specificity of several enzymes (ADH, FBALD, GAPDH, G3PDH, G6PDH and PGM) were found to be similar to those of other vertebrates. Differences were detected in ALP due to the absence of an intestinal-specific form typical of fish, amphibians, reptiles and birds; further differences were observed in GPI and MDH due to their tissue expression. The differences in LDH involve the LDH-A4 isozyme which was most common in tissues. Overall, comparison with other vertebrates reveals that in L. paradoxa the tissue-restricted expressions of some enzymes are similar, while others have retained an ancestral pattern and exhibit a more widespread tissue expression of genes.

LACTATE DEHYDROGENASE ISOZYMES AND THEIR GENETIC VARIATION IN FIFTEEN SPARIDAE SPECIES (PERCIFORMES, TELEOSTEI)

Abstract 1. 1. Differences in tissue patterns of Ldh enzyme-locus expressions were used to infer the exstent of divergence among 15 Sparidae species. 2. 2. Some Ldh locus-tissue expressions diverged markedly among species while others were conserved at the genus level. 3. 3. Differences between tissues, in terms of lactate dehydrogenase activity, were observed in all species. The patterns are species-specific, most likely monomorphic with the exception of Diplodus sargus . 4. 4. Unexpectedly large differences in the tissue patterns of lactate dehydrogenase-C (Ldh-C) gene regulation were observed between two species of fish of the genus Pagellus within the Sparidae family.

Malate dehydrogenase isozymes in fifteen sparidae species (perciformes, teleostei)

Abstract 1. 1. MDH isozymes were analyzed in seven different tissues in 15 Sparidae species using electrophoresis and isoelectric focusing. 2. 2. Species-specific patterns of enzymatic activity were identified with the sole exception of Sparus aurata and S. pagrus which showed the same pattern, thus indicating their close ties. 3. 3. Marked differences in tissue distribution of the different MDH isozymes were found between the species. 4. 4. The results are related to genetic, physiological and environmental factors.

Electrophoretic and isoelectrophoretic characteristics of hemoglobins of Italian ictalurids

Electrophoretic and isoelectrophoretic behaviour of the hemoglobins of Italian freshwater Ictalurids was analysed. Multiple and polymorphic hemoglobin patterns were found in Ictalurus sp. (I. nebulosus nebulosus?, I. melas?); multiple and monomorphic patterns in I. n. marmoratus and I. punctatus. Hypotheses are advanced for further investigation of the question.

Soluble eye lens proteins of Italian ictalurids

Abstract 1. 1. Soluble eye lens proteins of three species of Italian freshwater ictalurids were analyzed: Ictalurus sp., I. nebulosus marmoratus and I. punctatus . 2. 2. The electrophoretic and isoelectric focusing patterns were compared. 3. 3. Both techniques revealed species-specific patterns. I . sp. and I. nebulosus marmoratus exhibited very similar patterns, I. punctatus a quite distinct one. 4. 4. Some hypotheses warranting further investigation of the subject were proposed.

A comparative study of some soluble proteins of the genus Diplodus (Sparidae: Teleostei)

Abstract 1. 1. Soluble eye lens and muscle proteins of four species of the genus Diplodus (D. annularis, D. sargus, D. vulgaris, D. puntazzo ) were analyzed. 2. 2. Species-specific electrophoretic and isoelectric focusing patterns were found in both protein systems. 3. 3. Comparison of the soluble proteins of the eye lens and of the soluble proteins of the white skeletal muscle of the four species gave evidence that D. annularis and D. sargus are closely related and that they are only distantly related to D. vulgaris . 4. 4. Comparison also showed the relative taxonomic distance of D. puntazzo and, thus, the early detachment of this species from a presumptive common ancestral lineage.

Biochemical characteristics of mugilids in the lagoons of the Po delta

Abstract Electrophoretic method has been applied to biochemical classification of Mugilids in the Lagoons of the Po delta. Among the various proteins analysed the one which turned out to be the most useful was the lactate dehydrogenase enzyme (LDH) because it presents different patterns in the five species living in the above mentioned lagoon and does not show any variations in the course of ontogenesis. This caracteristic makes it possible to identify stocks of fry to be put into closed waters for subsequent cultivation. Moreover this method allows one to make certain phylogenetic speculations with regard to the origin of these species.