Identification and Characterization of a Halotolerant, Cold-Active Marine Endo-β-1,4-Glucanase by Using Functional Metagenomics of Seaweed-Associated Microbiota

ABSTRACTA metagenomic library was constructed from microorganisms associated with the brown algaAscophyllum nodosum. Functional screening of this library revealed 13 novel putative esterase loci and two glycoside hydrolase loci. Sequence and gene cluster analysis showed the wide diversity of the identified enzymes and gave an idea of the microbial populations present during the sample collection period. Lastly, an endo-β-1,4-glucanase having less than 50% identity to sequences of known cellulases was purified and partially characterized, showing activity at low temperature and after prolonged incubation in concentrated salt solutions.

Esterase Polymorphism for Analysis of Genetic Diversity and Structure of Wild Poinsettia (Euphorbia heterophylla) Populations

Native polyacrylamide gel electrophoresis was used in the current study to identify polymorphism in α- and β-esterase loci in leaf tissues of wild poinsettia plants for the analysis of genetic diversity and structure of populations. Seeds were collected from different plants in 12 different populations. Two to three allelic variants were at Est-1, Est-2, Est-3, Est-4, Est-5, Est-6, and Est-7 loci. The estimated proportion of polymorphic loci in populations is 87.5%. High and low values of observed and expected proportion of heterozygous loci in 12 populations confirm our suspicion that the populations are genetically structured (FST = 0.1663). The heterozygous deficiencies are evidenced by the positive value of FIS (0.1248). The positive FIS value indicates a deficit of heterozygous (12.48%) or an excess of homozygous plants, which could be the result of frequent herbicide application in areas where seeds were collected and/or the result of self-pollination. Overall inbreeding or nonrandom breeding, according to the significant FIT value (0.2703), did play a major role in shaping the genetic structure of these populations. Identity values represented in the dendrogram should play a more central role in developing policies to manage and control this species.

Mode of inheritance of the polymorphic esterases in Myzus persicae (Hemiptera: Aphididae) in Japan

Crossing experiments were conducted with 43 different parental clones of Myzus persicae (Sulzer) to clarify the genetic bases of esterase variations detected by electrophoresis. A total of 468 F1 clones obtained were analysed for variants at six polymorphic esterase loci, including one associated with resistance to organophosphorus insecticides (RAE). In addition, the effect of six different host plants on the activity of esterases was examined. The inheritance of variants at two loci could be explained by two-allele models, and that at three other loci by three-allele models, while segregation ratios at the RAE locus suggested a cumulative effect of the multiple genes. An interdependent assortment was found between two loci. The activity of the esterases detected in the alimentary canal was affected by the host plant. By combining the variants at the six polymorphic esterase loci with those in body colour, a total of 2592 colour-esterase forms were distinguishable. Thus esterases could be useful as genetic markers to study the genotypic composition and its dynamics of M. persicaepopulations.

GENETICS OF ISOZYMES AND ANALYSIS OF ISOZYMES LINKAGE AND MORPHOLOGICAL LOCI IN SUNFLOWER (Helianthus annuus L.) / GENETICA DE ISOFERMENTOS Y EL ACOMPLAMIENTO DE LÓCUSES MORFOLOGICOS E ISOFERMENTICOS EN GIRASOL / GENETIQUE DES ISOFERMENTS ET LIAISON DES LOCUS MORPHOLOGIQUES ET CEUX-CI D’ISOFERMENTS AU TOURNESOL

SUMMARY The genetics of anodal esterase (Est), cathodal esterase (cEst), cathodal acid phosphatase (cAcp) and malate dehydrogenase (Mdh) has been studied in mature seeds and leaves (genetics of cAcp and Mdh has not been studied in leaves) of sunflower (Helianthus annuus L.). A total of ten loci (four loci of anodal esterase, two loci of cathodal esterase, three loci of malate dehydrogenase and one locus of cathodal acid phosphatase) have been identified and described. Five esterase loci (Est1, Est2, Est3, Est4, cEst5), three malate dehydrogenase loci and one locus of cathodal acid phosphatase are expressed in seeds. Three esterase loci (Est2, cEst5 and cEst6) are expressed in leaves. The analysis of linkage between these loci has been made. Two linkage groups have been found. The sequence of the loci in the first linkage group was Mdh2-Est1- Est2-Est3-cEst5. In the second linkage group it was Est4-cAcp1. Linkages have been analyzed between three isoenzymatic loci expressed in leaves and between two loci controlling morphological traits (branched stem and male fertility restoration). The linkage between morphological traits and isoenzymatic loci has not been revealed. It has been revealed in Br-Rf pair.