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Biochemical Genetics (v.42, #3-4)

Variation of Genetic Expression During Development, Revealed by Esterase Patterns in Aedes aegypti (Diptera, Culicidae) by Alba Regina de Abreu Lima-Catelani; Carlos Roberto Ceron; Hermione E. Melara de Campos Bicudo (pp. 69-84).

Polyacrylamide gel electrophoresis was used to analyze esterase patterns during development of Aedes aegypti from the cities of Marília and São José do Rio Preto (SJRP), Brazil. The zymograms showed a total of 23 esterase bands, 22 of which were in the specimens from Marília and 19 in those from SJRP. These esterase bands were considered to be the product of 23 alleles distributed tentatively in eight genetic loci. Most of the alleles were developmentally regulated. The larval stage expressed the greatest number of them (19 alleles, from the eight loci, in Marília; and 17 alleles, from seven loci, in SJRP). The pupal stage expressed 10 alleles from seven loci, in both populations, and the adult stage expressed 8 alleles from five and six loci in SJRP and Marília, respectively. Some alleles that were active in every stage were developmentally controlled at the level of expression (amount of product). A single allele was constitutively and highly expressed, in larvae, pupae, and adults, in both populations. Differences in esterase synthesis among stages are probably due to regulatory mechanisms acting in agreement with the requirements of a variable number of processes in which esterases are involved. The larval stage is the most active in developmental processes and shows very intense intake of food and very high mobility. These features may demand increased esterase production at that stage. Comparison of the two populations examined showed (besides the existence of alleles that they do not share) that they exhibit differences in the control of expression of other alleles. Such findings may reflect genetic differences between founders in each population, but the possibility of involvement of the intensive use of insecticides in SJRP is also discussed.

Keywords: Aedes aegypti ; esterases; development; expression variation

Amino Acid Disorders in Mental Retardation: A Two-Decade Study from Andhra Pradesh by M. Swarna; A. Jyothy; P. Usha Rani; P. P. Reddy (pp. 85-98).

A screening program was carried out for amino acid disorders in children with mental handicaps from the state of Andhra Pradesh (India) during the last two decades. Forty-one (0.9%) cases were detected with amino acid disorders among 4500 children surveyed. We reported amino acid disorders of rare occurrence such as dicarboxylic aminoaciduria, hydroxykynureninuria, persistent hypertyrosinemia, hydroxyprolinemia, hypervalinemia, etc. A new metabolic defect threoninemia was also detected. We have observed a preponderance of males with amino acid disorders. Parental consanguinity was present in 54% of cases with amino acid disorders.

Keywords: amino acid disorders; mental retardation; metabolic defect

Analysis of the Genetic Structure of Endangered Bovine Breeds from the Western Pyrenees Using Dna Microsatellite Markers by F. Rendo; M. Iriondo; B. M. Jugo; A. Aguirre; L. I. Mazón; A. Vicario; M. Gómez; A. Estonba (pp. 99-108).

In the Western Pyrenees, three out of four native cattle breeds are in grave danger of extinction. Genetic variation of all four breeds was assessed by analyzing 478 animals using 11 microsatellite markers. A moderate/high within-breed variability was found, a favorable factor to consider when planning conservation and improvement programs. Interestingly, the only selected commercial breed, the Pirenaica, showed depressed heterozygosity levels and a low average number of alleles, perhaps explainable by intensive human selection exacerbated by a bottleneck effect. The Pirenaica also exhibited pronounced genetic differences and was the largest contributor of diversity among the breeds from the Western Pyrenees. Among endangered cattle breeds from this region, our results highlight the singularity of the Betizu. Geographic isolation among herds may be responsible for the large F_IS value found in the Betizu breed. Lastly, our study suggests that the use of highly selected breeds may be one of the causes of distortion in phylogenetic analyses.

Keywords: genetic structure; cattle breed; microsatellite; genetic diversity

High Genetic Variability of Esterase Loci in Natural Populations of Parus major, P. caeruleus, and P. ater by Simon Driesel; Lutz Bachmann; Michael Stauss; Gernot Segelbacher; Doris Flach; Jürgen Tomiuk; Jost Kömpf (pp. 109-119).

In Parus major, P. caeruleus, and P. ater the genetic variation of 16 isozyme loci was determined. The focus was on esterases that show high phenotypic variation in natural populations of these species. The degree of heterozygosity of the “non-esterase” loci was 0.029 ± 0.008 (P. major); 0.023 ± 0.012 (P. caeruleus), and 0.034 ± 0.034 (P. ater). Including the esterase loci with up to six alleles per locus the overall degree of heterozygosity increased to 0.130 ± 0.056 (P. major); 0.143 ± 0.067 (P. caeruleus), and 0.194 ± 0.090 (P. ater). We explain the high level of variability of esterases by gene amplification and subsequent selection for high allelic heterogeneity. Substrate specificity of loci is assumed to allow for multiple resistance against various toxic components. Large allelic variation of esterases, therefore, increases the fitness of Parus species and allows for utilizing new food resources.

Keywords: enzyme polymorphism; esterase; passerine birds; isoelectric focusing; ecotoxicology

High-Speed Detection of the G894T Polymorphism in Exon 7 of the eNOS Gene by Real-Time Fluorescence PCR with the Light-Cycler by Elena Sticchi; Cinzia Fatini; Francesca Gensini; Beatrice Battaglini; Agatina Alessandrello Liotta; Rosanna Abbate (pp. 121-127).

In endothelial cells nitric oxide (NO) is synthesized by endothelial-nitric oxide synthase (e-NOS), constitutively expressed and encoded by a 26-exon gene, located on chromosome 7q35-36. The prevalence of the T rare variant of the G894T polymorphism in exon 7 of the e-NOS gene (Glu→Asp amino acid substitution) has been reported to be significantly higher in patients with coronary spasm and coronary artery disease. To date G894T polymorphism detection is performed by PCR-RFLP assay. In order to establish a high-speed genotyping method, we have taken advantage of the Light Cycler instrument, a thermal cycler that combines rapid-cycle DNA amplification with a real-time fluorescence monitoring. This technology is based on hybridization of the adjacent fluorescently labeled probes with PCR products. This methodology is considered more accurate and less time-consuming than conventional PCR-RFLP assay. To validate this technique we genotyped 270 healthy subjects. The results were consistent with those obtained from PCR-RFLP assay.

Keywords: Light Cycler; real-time PCR; e-NOS gene; G894T polymorphism

Cloning and Characterization of a Novel Human TGF-β Activated Kinase-Like Gene by Jixi Li; Chaoneng Ji; Qisheng Yang; Jinzhong Chen; Shaohua Gu; Kang Ying; Yi Xie; Yumin Mao (pp. 129-137).

TGF-β activated kinase (TAK1) plays a critical role in the TGF-β signaling transduction pathway. By screening a human 18-week fetal brain library, we isolated a novel human TAK1-like (TAKL) gene. The gene encoded a putative protein of 242 amino acids, which shared a homology with human, mouse, and Xenopus TAK1. The TAKL gene was located in chromosome 21q21. Northern blot analysis revealed that the TAKL mRNA was expressed predominantly in peripheral blood leukocytes and ubiquitously in human adult and fetal tissues. TAKL was also expressed strongly in breast carcinoma GI-101, colon adenocarcinoma GI-112, and prostatic adenocarcinoma PC3.

Keywords: TGF-β activated kinase-like gene; Northern blot; RT-PCR

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Biochemical Genetics (v.42, #3-4)

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Biochemical Genetics (v.42, #3-4)