Leucine Aminopeptidase Isozymes Research Articles

Inheritance of leucine aminopeptidase isozymes in Picea abies K.

Inheritance of leucine aminopeptidase isozymes in Picea abies K. was investigated by analysing 6 mother-trees, progenies after selfing of all the mother-trees and progenies derived from 7 crosses. The isozyme variation in one specific region was due to a multi-allelic locus.

Development of leucine aminopeptidase activity during daylily flower growth and senescence

The possibility that exopeptidases, i.e. aminopeptidases and carboxypeptidases, in addition to the previously studied endopeptidase might also be developmentally regulated in daylily petals was examined. The level of leucine aminopeptidase and endopeptidase activities changed after the flower was fully open while that of carboxypeptidase activity remained relatively unchanged throughout senescence. Leucine aminopeptidase activity seemed to increase after the flower was fully open and peaked several hours earlier than endopeptidase did. Taken together, it is postulated that leucine aminopeptidase might play a role in protein turnover during flower opening and in the initiation of protein hydrolysis associated with petal senescence while the endopeptidase could be responsible for the breakdown of the bulk of proteins at the later stages. The drop in leucine aminopeptidase activity associated with the onset of daylily petal senescence was effectively halted by a cycloheximide treatment of cut daylily flowers for 24 h which was previously shown to prolong the vase life of the flowers and prevent protein loss from the petals. Apart from both being developmentally regulated in daylily petals, the leucine aminopeptidase activity and the previously studied endopeptidase are different in several aspects. They appear to have different pH optima, 8 for leucine aminopeptidase and 6.2 for endopeptidase. Unlike the endopeptidase activity, no new leucine aminopeptidase isozymes appeared during petal senescence, and the leucine aminopeptidase did not appear to belong to the cysteine class of proteolytic enzymes.

Identifying Pecan Cultivars by Isozymes and Inheritance of Leucine Aminopeptidase

More than 170 pecan [Carya illinoensis (Wangenh.) K. Koch] cultivars were evaluated formalate dehydrogenase, phosphoglucose isomerase, phosphoglucomutase, leucine aminopeptidase (LAP), and diaphorase (DIA). Isozymes of LAP were observed in two regions after starch gel electrophoresis. The faster region of activity (Lap-1) was polymorphic and consistently expressed in leaves, wood, and roots. Controlled crosses suggest that Lap-1 is simply inherited and controlled by at least two alleles. DIA was well resolved and storable only from leaf material and produced a complex banding pattern. The ability to differentiate among cultivars by isozymes was good. The 177 cultivars sorted into 72 classes. Forty of the cultivars (23%) possessed a unique series of isozyme patterns. Most cultivars (124 of 177) shared common banding patterns with less than four other cultivars. From the inheritance models of four isozymes, some historical pedigrees can be questioned. Most notably,' Western Schley' could not have been parented by `San Saba' based on the inheritance of Mdh-1 and Lap-1.

Spontaneous Genetic Variation for Leaf Rust Reaction in Sinvalocho MA Wheat

AbstractSpontaneous off‐type plants for leaf rust reaction to Argentine races 66 and 77 of Puccinia recondita tritici were found at rates of 3.4 per 1000 and 0.44 per 1000, respectively, in the progeny of self‐pollinated (bagged) spikes of Sinvalocho, MA wheat. Leaf rust reaction changes were associated to aneuploidy in most cases. The variation to race 66 was associated to monosomy of chromosome 6B or probably deletions on chromosome arm 6BL. Some off‐type plants however showed, in subsequent generations. changes for reaction to race 77 or simultaneous changes to races 66 and 77 as well as changes in leucine aminopeptidase isozyme expression, which cannot be explained on grounds of allelic dosage. The origin of these genetic and chromosomal changesis not clear in some cases, however, a common origin could be suggested by the presence of transposonlike elements.

Acid phosphatase and leucine aminopeptidase isozymes as biochemical markers of homogeneity in oil seed rape androgenetic lines

Extracts of cotyledons of Brassica napus plants (seed progenies of doubled haploid plants) were separated by electrophoresis on polyacrylamide gels and stained for acid phosphatase (ACP-E.C. 3.1.3.2.) and leucine aminopeptidase (LAP-E.C. 3.4.11.1.) enzymes to investigate the possibility of utilising isozymes as markers of homogeneity (purity) of plant populations. One zone of activity for acid phosphatase and two zones of activity for leucine aminopeptidase were identified on gels, some variation in isozyme patterns occurred in several androgenetic lines. This method is appropriate and consistent for testing the homogeneity of breeding lines-progenies of double haploid (D.H.) plants.

Apparent differential hatchabilities associated with degrees of hetcrozygosity at leucine aminopeptidase isozyme loci in the apple snail Pomacea canaliculata.

In order to examine probable association of hatchability of eggs with the degree of heterozygosi-ty at isozyme coding loci in the cultured populations of the apple snail Pomacea canaliculata, two loci of Lap-2 and Lap-3 linked each other, both coding leucine aminopeptidases, were selected for the progeny test. A series of observations on frequency distributions of hatchability from each egg lump ex-hibited a two modal distribution, indicating the apparent associations of lower and higher modal values with the degrees of combined heterozygosities of 0.5 and 0.75 at the two loci examined re-spectively. This result suggests an apparent advantage of heterozygotic pairs of the chromosomes in hatchability.

Grape Phylloxera (Homoptera: Phylloxeridae) Biotypes Confirmed by Electrophoresis and Host Susceptibility

Five of 27 species of grapes (Vitis arizonica, V. flexuosa, V. longii, V. monticola, and V. riparia) differ in their susceptibility to form leaf galls from two biotypes of the grape phylloxera (GPx), Daktulosphaira vitifoliae (Fitch). Electrophoretic differences were detected in GPx from six species of grapes (V. aestivalis, V. amurensis, V. champini, V. ‘Clinton’ (riparia × lubruscana), V. lincecumii, V. sampsonii, and V. treleasei). Clear banding differences were noted in isozymes of leucine aminopeptidase, phosphoglucose mutase, and malic enzyme.

The haemocytes and the activities of leucine aminopeptidase and alkaline phosphatase during development of Ceratitis capitata: Specific secretion of a leucine aminopeptidase isozyme

1. 1. The types of haemocytes during larval development were studied. 2. 2. The developmental profile of leucine aminopeptidase and alkaline phosphatase was studied. The maximum LAP activity was found to be in early larval development, while the maximum alkaline phosphatase during the white pupal stage. 3. 3. These activities were compared with those determined in cell-free haemolymph. 4. 4. Both hydrolytic enzymes have been found histochemically in the prohaemocytes and in the plasmatocytes. 5. 5. In cultured haemocytes experiments it was found that 64% of the total LAP activity was secreted into the incubation medium, while electrophoretic analysis of released LAP activity demonstrated that only LAP A isozyme was secreted. 6. 6. Based on the above results we suggest that both hydrolytic enzymes are functionally important throughout larval development.

Peroxidase and leucine-aminopeptidase in diploidMedicago species closely related to alfalfa: Multiple gene loci, multiple allelism, and linkage

The genetics of peroxidase and leucine-aminopeptidase isozymes was studied utilizing starch gel electrophoresis in the diploidsMedicago sativa L. (M. coerulea Less.) andM. falcata L. Three anodal and one cathodal sets of peroxidase isozymes identify four linked loci. In addition, two anodal sets of leucine-aminopeptidase isozymes identify two loci that may be linked. The allozymes at each of the loci segregated as expected for monomeric enzymes. However in several crosses there were deficiencies in the number of progeny in particular genotypic classes. This could result from the segregation of recessive deleterious genes linked to some of the allozyme alleles. This is the first report of multiple loci and multiple alleles determining isozymes inMedicago.

Ontogeny and tissue distribution of leucine aminopeptidase in Drosophila melanogaster

Drosophila melanogaster larvae contain two isozymes of leucine aminopeptidase that are detectable on starch gels. The more anodally migrating isozyme, LAP A, is first detected 12 hr after oviposition and is a soluble enzyme localized to the haemolymph. The specific activity of the other isozyme, LAP D, is highest in young larvae and associated with cell membranes, especially from the midgut and Malpighian tubules. It is probable that these two enzymes are both functionally and spatially unique in larvae of D. melanogaster.

Genetic control and distribution of leucine aminopeptidase in the cultivated chenopods (Chenopodium) and related weed taxa.

Isozymes of leucine aminopeptidase (LAP) in leaf tissue of the cultivated chenopods (Chenopodium quinoa and C. nuttalliae) and their sympatric weedy relatives (C. hircinum and C. berlandieri) can be electrophoretically resolved into a sum total of five anodally migrating bands. These are the products of two unlinked gene loci which apparently reflect genetic duplication via allotetraploidy. Accessions from the Andean and Mexican areas of cultivation are characterized by a lack of electrophoretically detectable variation. Andean weed and cultigen accessions appear to be genetically identical at both Lap loci, as do weed and cultigen material from Mexico. The two cultigens, and their sympatric weeds, can be differentiated by variation at the Lap-B locus, whereas they are monomorphic at Lap-A. This locus is, however, highly polymorphic in weedy C. berlandieri populations of western North America.

The effects of freeze-preservation on some pollen enzymes. 1. Freeze-thaw stresses

Summary Isozyme patterns of nonspecific esterase, leucine aminopeptidase, acid and alkaline phosphatases and peroxidase were studied to aid explanation of the nature of freeze-thaw injury to pollen. Fresh samples of Lilium longiflorum L. and Zea mays L. pollen were frozen at rates between 200 and 0.5°C/min and thawed at rates ranging between 218 and 2.5°C/min. Soluble enzymes were extracted from pollen and analyzed by disc electrophoresis on 7.5% polyacrylamide gels. The gels were stained for enzymes using substrate specific stains and the stained gels were scored for isozyme patterns, migration rate and relative activity. The data suggest that isozymic alterations of nonspecific esterase, acid and alkaline phosphatases, peroxidase and to a lesser extent leucine aminopeptidase are associated with freezing and thawing treatments. Generally, a decrease in enzyme stainability could be observed with freezing rates below 180 or 150°C/min. A diffused staining pattern of some enzymes may be a reflection of conformational changes. Increased acid phosphatase activity of frozen-thawed samples may indicate lysosomal damage. The isozymes of leucine aminopeptidase remained fairly stable in most treatments.

Genetic polymorphism of leucine aminopeptidase in canine plasma.

SummaryGenetic polymorphism was found in the isozymes of leucine aminopeptidase in the canine plasma. Analysis of parentage records of the dogs examined revealed that the phenotypic variation of leucine aminopeptidase isozymes was controlled by one autosomal locus, designated Lap, with two codominant gene alleles, LapA and LapB, though individuals of homozygous B type were not found in the specimen used. The gene frequencies were 0.97 for LapA and 0.03 for LapB in most of the dog breeds examined. Higher frequencies for LapB (0.11–0.25) were obtained in breeds such as Pointer, Doberman pinscher, Boxer, Borzoi and San'in‐Shiba (a Japanese native breed), while in German shepherd, Collie, and two of the Japanese native breeds, Akita and Kishu, phenotype of the isozyme seemed to be fixed to homozygous A (LapA/LapA).

Leucine aminopeptidase variations in human foetal organs.

Leucine aminopeptidase isozymes were examined in the extracts of organs from 70 human foetuses of varying intrauterine age. In some organs (intestine, kidney and pancreas) developmental differences we