SYSTEMATIC ANALYSIS OF SPHAEROPLEA (CHLOROPHYCEAE)1

A systematic investigation of the genus Sphaeroplea was conducted using cladistic analyses of both structural and isozyme characters for the same set of taxa. The structural data were not able to fully resolve some of the taxa while the isozyme data did produce a tree in which all nodes were supported by data. The structural characters were relatively consistent with one another, whereas the isozyme characters were much less internally consistent. Results from independent, cladistic analyses of both data sets support the concept that among those Sphaeroplea species investigated, S. fragilis Buchheim et Hoffman had an early divergence. The two data sets differed primarily in that the structural data support monophyly of the genus Sphaeroplea and the isozyme data do not. The greater relative consistency of the structural data suggests better support for trees inferred from its analysis. Furthermore, searches for character congruence between the two data sets revealed isozyme data which support monophyly of the genus Sphaeroplea, but had been overwhelmed by conflicting isozyme characters.     

Isozyme gene markers in Vicia faba L.

Summary This study was conducted to assess the genetic basis of the variability observed for the glutamate oxaloacetate transaminase (GOT), Superoxide dismutase (SOD), esterase (EST), and malate dehydrogenase (MDH) isozyme systems in different open-pollinated Vicia faba varieties. Individual plants showing contrasting zymogram patterns were simultaneously selfed and cross-combined. Crossing was unsuccessful in producing progeny, and only selfed progenies were suitable for genetical analysis of isozyme variability. Three zones of GOT activity were made visible. The isozyme of GOT-2 and GOT-3 zones were dimeric and under the control of three alleles at the Got-2 locus and two alleles at the Got-3 locus, respectively. The isozymes of the GOT-1 zone did not show any variability. Three zones of SOD isozyme activity were made visible. The isozymes occurring in the SOD-1 (chloroplastic isozyme form) and SOD-2 (cytosol isozyme form) zones were dimeric and under the control of two alleles at the Sod-1 and Sod-2 loci. The isozyme visualized in the SOD-3 zone (mitochondrial isozyme form) were tetrameric and under the control of two alleles at the Sod-3 locus. Apparently the isozymes made visible in the most anodal esterase zones EST-1, EST-2, and EST-3 were monomeric, and the occurrence of two alleles at each of two different loci explained the variability observed in the EST-2 and EST-3 zones. For MDH, only two five-banded zymogram pattern types were found, and every selfed progeny showed only one of the two zymogram type, indicating that each individual possessed fixed alleles at the loci controlling MDH isozyme. Got-2, Got-3, Sod-1, Sod-2, and Sod-3 appear to be five new isozyme gene markers that can be useful in Vicia faba breeding for linkage study, varietal fingerprinting, outcrossing rate estimate, and indirect selection for quantitative characters.     

Comparative isozyme polymorphisms of north American eastern gamagrass,Tripsacum dactyloides var.dactyloides and maize,Zea mays L.

Random samples, consisting of at least 100 individual seedlings, were taken from the diploid (2n=2x=36) eastern gamagrass (Tripsacum dactyloides var.dactyloides) and assayed to determine which of 12 enzyme marker loci and isozyme systems would be most informative in providing satisfactory resolution of both maize andTripsacum isozyme systems. For comparison, eight maize inbreds were included in the study to aid evaluation and comparison of the various isozyme systems. In addition, evaluations were conducted to identify if the identified optimum isozyme system could be used to detectTripsacum introgression in maize following a maize ×Tripsacum backcrossing scheme. Using the established isozyme techniques for maize (Zea mays L.), theAdh, Pgd, Cat, Est, B-Glu, Got, Idh, Tpi isozyme systems detected no polymorphism among theTripsacum individuals assayed. TheEst andB-Glu systems forTripsacum were unscorable due to poor staining and resolution. TheAcp, Mdh, Pgm, andPhi isozyme systems were found to be satisfactory markers for differentiating between eastern gamagrass individuals as well as detectingTripsacum introgression in maize. The availability of useful isozyme systems which can simultaneously provide significant isozyme resolution of maize,Tripsacum and maize-Tripsacum backcross hybrids, on a single gel system, will be useful for the detection of marker assistedTripsacum introgression into maize. In addition, the identification of a set of variable biochemical markers should also assist breeding, selection and genetic manipulations in eastern gamagrass.The use of company names in this publication does not imply endorsement by the USDA-ARS, or the product names of criticism of similar ones not mentioned. All programs and services of the U.S. Department of Agriculture are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, age, marital status, or handicap.     

Evaluation of isozyme systems in Citrus to facilitate identification of fusion products

Summary Ten isozymes were analyzed in nucellar calli of nine Citrus species and cultivars and roots of the corresponding apomictic seedlings. The zymograms obtained can be divided into three groups: a) isozyme patterns similar in both calli and roots, b) isozyme patterns similar in calli but variable in roots, and c) isozyme patterns variable in both calli and roots. Analysis of these ten isozyme systems may facilitate identification of fusion products in Citrus.Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 354-E, 1982 series     

Secretion of Hexosaminidase Isozymes by Tetrahymena*

SYNOPSIS. Tetrahymena pyriformis strain HSM secrete large quantities of lysosomal acid hydrolases into the medium. The finding that 2 isozymes of β-N-acetylhexosaminidase (2-acetamido-2-deoxy-β-D-glucoside acetamidodeoxyglucohydrolase; EC 3.2.1.30) could be resolved by DEAE ion exchange chromatography and of possible differences between the secreted mixture and the intralysosomal hexosaminidase activity suggested that Tetrahymena might prove useful for studies of the control of lysosomal hydrolase isozyme secretion. In the present paper, we report a considerable purification of these isozymes and describe a number of their kinetic properties. Four isozymes were isolated into 2 major forms, A₁ and B₁, and 2 minor forms, A₂ and B₂, which were similar to the respective major forms in all kinetic properties tested. Hexosaminidase B₁ has a molecular weight of ?93,000 daltons and is inhibited by high concentrations of p-nitrophenyl-N-acetyl-β-D-glucosaminide. The inhibition is reversed by ethanol. Hexosaminidase A₁ has a molecular weight of ?170,000 and is not inhibited by high concentrations of substrate. The A forms are relatively less active against p-nitrophenyl-N-acetyl-β-D-galactosaminide than the B forms. Neither hexosaminidases A₁ or B₁ has any endo-β-N-acetylhexosaminidase activity. Comparison of the properties of the 2 major isozymes suggested that measurements of activity obtained under different assay conditions could be used to quantitate the amount of each isozyme in a mixture of the two. Log- and early stationary-phase cells secrete ?20% of isozyme A and 80% of isozyme B into the medium or into a dilute salt solution. With increasing culture age the fraction of isozyme A secreted rises to over 90%. Supplementation of the proteose-peptone growth medium with glucose causes a decrease in total hexosaminidase subsequently secreted but with no change in proportion of each isozyme. Cells suspended in a dilute salt solution containing 0.1 mM L-propranolol secrete slightly more isozyme A than do control cells suspended without L-propranolol. Phenoxy-benzamine (0.2 mM) causes a slight decrease in the proportion of isozyme A released.     

三倍体罗汉果及其亲本的同工酶比较研究

为了加快三倍体罗汉果育种的进程和效率,进一步提高其亲本选择性,该文对F1代3x罗汉果与其4x和2x亲本的过氧化物酶(POD)同工酶和酯酶(EST)同工酶进行了比较。结果表明:F1代3x罗汉果与其4x和2x亲本的POD和EST同工酶均有一定差异,3x和4x的POD和EST同工酶不同迁移率的平均酶带数目较2x多,酶带活性也较强;4x的POD同工酶数目较3x的多,但EST同工酶两者差异较小;F1代3x罗汉果的同工酶均出现了与其4x和2x亲本不同的新酶带,预示着其可能具有的杂种优势;聚类分析结果显示,F1代3x罗汉果与其4x母本的遗传距离更近,并且当4x母本间亲缘遗传关系较近时,其F1代3x在亲缘遗传上也相聚较近,说明F1代3x在亲缘遗传上更倾向于其4x母本。由于三倍体罗汉果育种亲本间存在杂种优势,且更倾向于其母本遗传,因此通过该研究可以初步总结出三倍体罗汉果及其父本、母本的遗传规律,并提出罗汉果三倍体良种选育的建议,即在3x罗汉果育种时需要更加关注4x母本的优良性状表现,并以亲本的遗传背景为基础,选择遗传差异较为显著的父本和母本。     

Phylogenetic relationships inSecale (Poaceae): An isozymatic study

The genetic frequencies of 9 isozyme loci have been estimated in 23 samples of 4 species ofSecale by means of starch gel electrophoresis. The populations ofS. silvestre andS. vavilovii were monomorphic and uniform within each species, those ofS. montanum andS. cereale were polymorphic for most of the isozyme loci. On the basis of isozyme patterns as well as allelic and genotypic frequencies of isozyme loci,S. silvestre can be distinguished fromS. vavilovii, and both fromS. cereale andS. montanum; but there is no clear differentiation between the two latter species. Clusters constructed from genetic distances separateS. silvestre andS. vavilovii, whereasS. cereale andS. montanum were grouped together. The isozymatic data presented here, along with cytogenetic and life habit data, agree with the generally admitted existence of 4 species inSecale, and support the relationships suggested byKhush & Stebbins (1961).     

Geographic distribution and multilocus organization of isozyme variation of rice (Oryza sativa L.)

Genetic organization of isozyme variation in rice (Oryza sativa L.) was investigated based on 17 polymorphic isozyme loci using a sample of 511 accessions of worldwide origin. The genetic diversity within the species was very high (H=0.36 with 4.82 alleles per locus), as compared with most selfing plant species. Three diversity centers were detected for isozyme variation including South Asia, China and Southeast Asia. The accessions were classified into three well-differentiated cultivar groups corresponding to the indica and japonica subspecies, and a new unnamed group. Variation within the cultivar groups accounted for 80% of the total isozyme variation. Within-country variation accounted for 58% of the total variation while among-region and among-country variation within the cultivar groups accounted for only 14% and 8% of the total variation. Analyses using log-linear models revealed that pronounced non-random associations between and among alleles at many unlinked isozyme loci were organized in a non-hierarchical pattern, and subspecific and macro-geographic differentiation was much more pronounced in multilocus phenotype frequencies than in allelic frequencies at individual loci. These results suggest that selection on multilocus gene complexes was largely responsible for the maintenance of the extensive isozyme variation within the species and the indica-japonica differentiation. Our results further suggest the independent domestication of indica and japonica, the dual origins of the indica rice from China and South Asia (India), and the differentiation of the ecotypes ’javanica’ and the ’temperate japonica’ within the japonica subspecies. Received: 5 August 1999 / Accepted: 13 December 1999     

Genetic structure among Thai populations of Aedes aegypti mosquitoes

Thirty‐one field populations of Aedes aegypti (L.) were compared using isozyme starch gel electrophoresis to characterize genetic variation between populations. Ae. aegypti were collected from seven provinces in Thailand. Thirty‐one isozyme encoding loci, including 19 polymorphic loci, were characterized. Only small levels of genetic differentiation were observed among the 31 district populations in the seven provinces. Isolation by distance among populations from the seven provinces showed no correlation between genetic variation and geographical distance.     

Isozyme Variability in Plants Regenerated from Calli of Cereus peruvianus (Cactaceae)

Morphological and isozyme variation was observed among plants regenerated from callus cultures of Cereus peruvianus. Different morphological types of shoots (68%) were observed in 4-year-old regenerated plants, while no distinct morphological variants were observed in plants grown from germinated seeds. Isozyme patterns of 633 plants regenerated from calli and of 261 plants grown from germinated seeds showed no variation in isocitrate dehydrogenase isozyme, and the differential sorbitol dehydrogenase, alcohol dehydrogenase, malate dehydrogenase, acid phosphatase, and peroxidase isozyme patterns observed in regenerated plants were attributed to nonallelic variation. Allelic variation was detected at three isoesterase loci. The proportion of polymorphic loci for both populations was 13.6% and the deviation from Hardy–Weinberg equilibrium for the Est-1 and Est-7 loci observed in somaclones was attributed to the manner in which the regenerant population was established. The high values for genetic identity among regenerant and seed-grown plant populations are in accordance with the low levels of interpopulation genetic divergence. In somaclones of C. peruvianus, morphological divergence was achieved within a short time but was not associated with any isozyme changes and also was not accompanied by biochemical genetic divergence.     

Origin of human triosephosphate isomerase isozymes: Further evidence for the single structural locus hypothesis with Japanese variants

Summary Four electrophoretic variants of human erythrocyte triosephosphate isomerase (TPI) have been studied to investigate the origin of the multiple forms of human TPI, in particular the constitutive TPI-B isozyme and the cell division-associated TPI-A isozyme. The variant phenotype expressed by the constitutive TPI-B isozyme in both erythrocytes and peripheral lymphocytes was also expressed by the cell division-associated isozymes in mitogen-stimulated lymphocytes and hair root cells. These results strongly support the hypothesis of Decker and Mohrenweiser (1981) that TPI-B and TPI-A originated from the same structural gene. We also found that the isozyme e is different from TPI-A with respect to both its electrophoretic mobility and heat stability. This finding is in contrast to the recent conclusion of Yuan et al. (1981) that both the isozyme e and TPI-A are deamidation products of TPI-B.     

Associations between isozyme phenotypes and environment in the slender wild oat (Avena barbata) in Israel

Summary Collections from 31 populations of A. barbata from diverse habitats in Israel were assayed electrophoretically for seven enzyme systems. Phenotype frequencies were scored in nine enzyme zones, probably representing 27 loci, to determine isozyme variability within and among populations. Many different isozyme phenotypes were found in all of the populations; also the array of isozyme phenotypes found in each population differed distinctly from that found in each other population. Overlays of phenotypic frequencies on map locations showed that isozyme variability is distributed in mosaic patterns not related to geographical distance. Principal-component and multiple-regression analyses revealed that temperature and moisture-related variables are significantly correlated with particular isozyme phenotypes. Further, the mosaic patterns of isozyme variation were found to correspond closely to mosaic patterns of the habitat. This structuring of the genetic variability into multilocus combinations was attributed to the combined effects of directional and diversifying selection. Comparisons of patterns and extent of genetic variation in Israel and California led to the conclusion that the evolution of ecotypes, each adapted to a specific habitat and marked by a particular set of enzyme alleles, has proceeded further in Israel, where A. barbata is endemic, than in California, where it is a recent introduction.This study was supported in part by NSF Grant BMS-01113-A01. Seed collections were supported by a United States-Israel Binational Science Foundation Grant     

Nuclear location of phosphoglycerate mutase BB isozyme in rat tissues

Summary We have previously reported (Ureña et al. Eur. J. Cell Biol. 1990) that in skeletal muscle, type MM phosphoglycerate mutase isozyme is present in the nucleus as well as in the cytosol. To determine whether type BB phosphoglycerate mutase isozyme is also present in nucleus, the subcellular location of this isozyme was studied in different rat tissues by cell fractionation and immunogold techniques. With the aid of high affinity-purified anti-phosphoglycerate mutase BB isozyme antibodies, the isozyme was located in the nucleus of neuronal, astroglial and liver cells but not in the nucleus of oligodendroglial and endothelial cells. Biochemical studies on purified nuclear fractions also demonstrated the presence of phosphoglycerate mutase activity in the nucleus. Both immunocytochemical and biochemical techniques showed that nuclear phosphoglycerate mutase-specific activity depended on the type of cell.Abbreviations PGAM phosphoglycerate mutase - PGAM-M(M) muscle specific subunit (isozyme) of PGAM - PGAM-B(B) brain type subunit (isozyme) of PGAM - ssDNA single stranded DNA - PBS 0.001 M phosphate buffer, pH 7.4, containing 0.15 M NaCl - kDa kilodalton     

Changes in the isozyme composition of antioxidant enzymes in response to aminotriazole in leaves ofArabidopsis thaliana

The changes in isozyme profiles of catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR) during severe deactivation of total CAT activity by aminotriazole (AT) treatment were investigated in the leaves ofArabidopsis thaliana (Columbia ecotype) in relation to H₂O₂-mediated oxidative stress. In spite of striking deactivation of total CAT activity by 0.1 mM AT, there were no significant differences in H₂O₂ levels or total leaf soluble protein contents including a Rubisco in both the control and AT-treated leaves. On the other hand, one specific protein band (molecular mass, 66 kD) was observed on the SDS-gel from leaf soluble proteins whose staining intensity was strikingly enhanced by AT treatment for 6 h. However, this band disappeared at 12 h. In the native-gel assays of CAT, POD, APX and GR isozymes, AT remarkably inhibited the expression of the CAT1 isozyme with no effects on CAT2 and CAT3, and generally had no effect on POD isozyme profiles. However, AT stimulated the intensity of activities of pre-existing APX1 and GR1 isozymes. In particular, it induced a new synthesis of one GR isozyme. Therefore, these results collectively suggest that a striking deactivation of total CAT activity by AT inA. thaliana leaves largely results from the suppression of CAT1 isozyme, and that APX1, GR1, and a newly synthesized GR isozyme could complement the role of CAT1 to metabolize H₂O₂ into non-toxic water.     

Retina-specific LDH isozyme in blueback herring, Alosa aestivalis (Mitchell), and alewife, Aiosa pseudoharengus (Wilson)

The retina of 390 Alosa aestivalis and 410 Alosa pseudoharengus have been examined by means of starch-gel electrophoresis. The retina-specific E₄ isozyme has been found to occur in all the fish examined. This study demonstrates for the first time that the E₄ isozyme occurs in A. aestivalis. Because the E₄ isozyme is not polymorphic and has an identical mobility in A. pseudoharengus and in A. aestivalis it is neither suitable for use as a species identification characteristic nor a population marker. Alosa aestivalis and Alosa pseudoharengus are two commercially important ana-dromous species of fish in New Brunswick, Canada. These two species may occur together in the same spawning runs but w^rhile A. pseudoharengus has a wide distribution along the East coast of North America (Leim & Scott, 1966) A. aestivalis occurs in a very limited area in Canada where it is at the northern limit of its range and because of increasing threat of pollution has been listed by McAllister (1970) as one of 17 endangered species. These two species of fish are morphologically very similar and can only be separated by the colour of the abdominal peritoneum (Leim & Scott, 1966). McKenzie (1973) has compared these two species by means of protein electrophoresis and found that while the muscle myogen patterns were species specific, the LDH patterns were the same in both species. He described these two species as five isozyme fish showing the LDH isozymes A₄, A₃B, A₂B₂, AB₃ and B₄. Since Horowitz & Whitt (1972) have reported the presence of the E₄ isozyme in the retina of some teleosts including. A. pseudoharengus but not including A. aestivalis, I considered it worth-while to re-examine A. aestivalis and A. pseudoharengus to find out whether A. aestivalis possessed this isozyme and, if so, whether the mobility of the isozyme could be used as a species identification characteristic and as a population marker. The fish used in this study were collected from five different locations during the 1971 spring migration period and held deep frozen for eight months before they were examined. They were identical to the specimens used for the study reported by McKenzie (1973) where the collection dates, numbers of fish and geographic locations are given. One eyeball from each of 390 A. aestivalis and 410 A. pseudoharengus was removed. Each eyeball was homogenized in 10 drops of distilled water and allowed to stand for one hour at 4^oC. The samples were then centrifuged for 10 min at 12 000 g. The supernatants were used immediately for vertical starch-gel electrophoresis. The apparatus used was that described by Boyer & Hiner (1963). The conditions of electrophoresis were the same as used by Saunders & McKenzie (1971). The LDH bands were stained by the deposition of blue formazan dyes in the regions of LDH activity. The stain formula and details of methods are given in Whitt (1970). The LDH isozyme patterns of all the fish examined were identical. The location of the isozymes A₄, A₃B, A₂B₂, AB₃ and B₄ are indicated in Fig. 1. A₄ is abundant in muscle while B₄ is abundant in heart. Because the LDH subunits assemble preferentially into homodimeric pairs before forming tetramers (Markert & Ursprung, 1971). A₄. A₂B₂ and B₄ show up in electropherograms as strong bands while A₃B and AB₃ show up as weak bands. The retina-specific isozyme E₄ is shown between B₄ and AB₃. Whitt (1970) has already demonstrated that A. pseudoharengus is a five isozyme fish. This has been confirmed by McKenzie (1973) who also compared both A. pseudoharengus and A. aestivalis and found these five isozymes had identical mobilities in both species of fish. The present study demonstrates for the first time that the retina-specific E₄ occurs in A. aestivalis where it has the same electro-phoretic mobility as that of A. pseudoharengus. The patterns are the same and do not appear to vary with geographic origin of the fish. The reason why the presence of the E₄ isozyme was demonstrated in the present study and not in the previous one (McKenzie, 1973) is because of the method used. In that study the migration length was not long enough to sufficiently separate the enzymes. In the present study vertical starch-gel electrophoresis which allows for long migration distances was used. As has already been shown for the A-B isozymes (McKenzie, 1973), the E₄ isozyme is not polymorphic in these two species of fish. It therefore has no use as apopulation marker. Because the E₄ isozyme has an identical mobility in both species of fish, it cannot be used as a species identification characteristic.     

The control of wheat malate dehydrogenase by rye chromosomes

A quantitative analysis of malate dehydrogenase isozymes has been carried out in a hexaploid wheat Triticum aestivum variety Holdfast, a diploid rye Secale cereale variety King II, a series of seven addition lines each having the Holdfast wheat chromosome complement, and also a different homologous pair of King II rye chromosomes. In young shoots of three of these addition lines grown in a defined salts medium lacking sucrose, at least one isozyme activity was elevated. This did not occur in shoots grown in a medium containing 0.5% sucrose or in the Triticale possessing the full wheat and rye chromosomal complements grown in the absence of exogenous sucrose. On the basis of cellular localization and substrate inhibition studies, the particular isozyme activities enhanced by the rye chromosomes were indistinguishable from isozyme activities in Holdfast wheat and dissimilar to all malate dehydrogenase isozyme activities observed in King II rye. These results suggest that three different rye chromosomes produce gene products which can interact with the wheat malate dehydrogenase regulatory system.     

Genetic Diversity Among Iranian Isolates of Rhizoctonia solani Kühn Anastomosis Group1 Subgroups Based on Isozyme Analysis and Total Soluble Protein Pattern

Rhizoctonia solani is a destructive fungal pathogen with a wide host range. The R. solani complex species includes several divergent groups delimited by affinities for hyphal anastomosis. In this study, genetic variation among 20 isolates of R. solani anastomosis group 1 (AG1) subgroups (AG1‐IA and AG1‐IB) collected from Mâzandaran province, Iran, and standard isolates of these subgroups, was determined by isozyme analysis and total soluble protein profile. Mycelial protein pattern and isozyme analysis were studied using denaturing and non‐denaturing polyacrylamide gel electrophoresis, respectively. A total of 15 enzyme systems were tested, among which six enzymes including esterase, alkaline phosphatase, superoxide dismutase, octanol dehydrogenase, lactate dehydrogenase and mannitol dehydrogenase generated distinct and reproducible results. The soluble protein patterns were similar among the R. solani isolates examined; however, minor differences in banding pattern were observed between the two subgroups. In isozyme analysis, a total of 64 electrophoretic phenotypes were detected for all six enzymes used. Based on cluster analysis and similarity matrix, the fungal isolates were divided into two genetically distinct groups of I and II consistent with the previously reported AG1‐IA and AG1‐IB subgroups in AG1. Group I represented all isolates belonging to AG1‐IA subgroup, whereas group II represented all isolates belonging to AG1‐IB subgroup. Results from isozyme analysis suggest that the subgrouping concept within AGs is genetically based.     

Characterization of the esterase isozymes of Ips typographus (coleoptera,scolytidae)

Four esterase isozymes hydrolyzing α-naphthyl acetate (α-NA) were detected screening whole body homogenates of larvae and adults of Ips typographus by electrophoresis. Two of the four isozymes (isozymes 3 and 4) were not detected by α-NA staining in the pupal stage, but topical application of juvenile hormone III (JH III) on the pupa induced these isozymes. The JH esterase (JHE) activity on the gel was associated with the proteins of isozyme 2. The compounds OTFP, PTFP, and DFP inhibited this catalytic activity of isozyme 2 on the gel at low concentrations, whereas the proteins of isozyme 3 and 4 were affected only at higher concentrations. A quantitative developmental study was performed to characterize which of the esterases hydrolyzed JH III, using a putative surrogate substrate for JH (HEXTAT) and α-NA. The I₅₀ of several esterase inhibitors and the JH metabolites were also defined. All findings supported the results that a protein associated with isozyme 2 is catabolizing JH and that isozymes 3 and 4 are the main contributors to the general esterase activity on α-NA. The JHE from Tenebrio molitor was purified by affinity chromatography. Although the recovery was low, an analytical isoelectric focusing gel showed that the JHE activity of the purified enzyme. T. molitor cochromatographed at the same pl as the JHE activity of I. typographus. Arch. Insect Biochem. Physiol. 34:203–221, 1997. © 1997 Wiley-Liss, Inc.     

Inheritance,intracellular localization,and genetic variation of phosphoglucomutase isozymes in maize (Zea mays L.)

Phosphoglucomutase (PGM; EC 2.7.5.1) isozyme variants were studied in a large number of inbred lines, crosses, and races of maize (Zea mays L.). Patterns of Mendelian inheritance demonstrated for PGM isozyme variants indicated that they are encoded by nuclear genes. Two unlinked loci, Pgm1 and Pgm2, located on the long arm of chromosome 1 and the short arm of chromosome 5, respectively, specify the observed electrophoretic variation on starch gels. No intra- or interlocus hybrid bands were found, suggesting that each isozyme band consists of a single polypeptide. PGM isozymes were present in all plant parts studied and the activity specified by both loci appears to reside in the cytoplasm. In studies of 520 racial collections of maize from Latin America, a single allele at each locus predominated in most collections. Likewise, the same alleles predominated in a set of 406 inbred lines of maize from the United States and Canada.This work was supported in part by NIH Research Grant GM 11546.Paper No. 8496 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina.