BE3 is the major branching enzyme isoform required for amylopectin synthesis in C.

Starch-branching enzymes (BEs) are essential for starch synthesis in both plants and algae where they influence the architecture and physical properties of starch granules. Within Embryophytes, BEs are classified as type 1 and type 2 depending on their substrate preference. In this article, we report the characterization of the three BE isoforms encoded in the genome of the starch producing green algae : two type 2 BEs (BE2 and BE3) and a single type 1 BE (BE1).

Further insight into the involvement of PII1 in starch granule initiation in Arabidopsis leaf chloroplasts.

The control of starch granule initiation in plant leaves is a complex process that requires active enzymes like Starch Synthase 4 and 3 (SS4 or SS3) and several noncatalytic proteins such as Protein Involved in starch Initiation 1 (PII1). In Arabidopsis leaves, SS4 is the main enzyme that control starch granule initiation, but in its absence, SS3 partly fulfills this function. How these proteins collectively act to control the initiation of starch granules remains elusive.

NegFluo, a Fast and Efficient Method to Determine Starch Granule Size and Morphology in Plant Chloroplasts.

Starch granules that accumulate in the plastids of plants vary in size, shape, phosphate, or protein content according to their botanical origin. Depending on their size, the applications in food and nonfood industries differ. Being able to master starch granule size for a specific plant, without alteration of other characteristics (phosphate content, protein content, etc.

PII1: a protein involved in starch initiation that determines granule number and size in Arabidopsis chloroplast.

The initiation of starch granule formation is still poorly understood. However, the soluble starch synthase 4 (SS4) appears to be a major component of this process since it is required to synthesize the correct number of starch granules in the chloroplasts of Arabidopsis thaliana plants. A yeast two-hybrid screen allowed the identification of several putative SS4 interacting partners.

Proteome Analysis of Potato Starch Reveals the Presence of New Starch Metabolic Proteins as Well as Multiple Protease Inhibitors.

Starch bound proteins mainly include enzymes from the starch biosynthesis pathway. Recently, new functions in starch molecular assembly or active protein targeting were also proposed for starch associated proteins. The potato genome sequence reveals 77 loci encoding starch metabolizing enzymes with the identification of previously unknown putative isoforms.

Expression of Escherichia coli glycogen branching enzyme in an Arabidopsis mutant devoid of endogenous starch branching enzymes induces the synthesis of starch-like polyglucans.

Starch synthesis requires several enzymatic activities including branching enzymes (BEs) responsible for the formation of α(1 → 6) linkages. Distribution and number of these linkages are further controlled by debranching enzymes that cleave some of them, rendering the polyglucan water-insoluble and semi-crystalline. Although the activity of BEs and debranching enzymes is mandatory to sustain normal starch synthesis, the relative importance of each in the establishment of the plant storage polyglucan (i.

Nuclear microsatellite loci for Arabidopsis halleri (Brassicaceae), a model species to study plant adaptation to heavy metals.

Premise Of The Study: Arabidopsis halleri is a model species to study the adaptation of plants to soils contaminated by zinc, cadmium, and lead. To provide a neutral genetic background with which adaptive genetic markers could be compared, we developed highly polymorphic neutral microsatellite markers.

Methods And Results: Using a microsatellite-enriched library method, we identified 120 microsatellite loci for quantitative trait locus (QTL) mapping analysis, of which eight primer pairs were developed in a single multiplex for population genetic studies.

Gynodioecy in structured populations: understanding fine-scale sex ratio variation in Beta vulgaris ssp. maritima.

Natural selection, random processes and gene flow are known to generate sex ratio variations among sexually polymorphic plant populations. In gynodioecious species, in which hermaphrodites and females coexist, the relative effect of these processes on the maintenance of sex polymorphism is still up for debate. The aim of this study was to document sex ratio and cytonuclear genetic variation at a very local scale in wind-pollinated gynodioecious Beta vulgaris ssp.

Sex-specific fitness variation in gynodioecious Beta vulgaris ssp. maritima: do empirical observations fit theoretical predictions?

In gynodioecious species, in which hermaphroditic and female plants co-occur, the maintenance of sexual polymorphism relies on the genetic determination of sex and on the relative fitness of the different phenotypes. Flower production, components of male fitness (pollen quantity and pollen quality) and female fitness (fruit and seed set) were measured in gynodioecious Beta vulgaris spp. maritima, in which sex is determined by interactions between cytoplasmic male sterility (CMS) genes and nuclear restorers of male fertility.

Structural and content diversity of mitochondrial genome in beet: a comparative genomic analysis.

Despite their monophyletic origin, mitochondrial (mt) genomes of plants and animals have developed contrasted evolutionary paths over time. Animal mt genomes are generally small, compact, and exhibit high mutation rates, whereas plant mt genomes exhibit low mutation rates, little compactness, larger sizes, and highly rearranged structures. We present the (nearly) whole sequences of five new mt genomes in the Beta genus: four from Beta vulgaris and one from B.

Genetic architecture of zinc hyperaccumulation in Arabidopsis halleri: the essential role of QTL x environment interactions.

This study sought to determine the main genomic regions that control zinc (Zn) hyperaccumulation in Arabidopsis halleri and to examine genotype x environment effects on phenotypic variance. To do so, quantitative trait loci (QTLs) were mapped using an interspecific A. halleri x Arabidopsis lyrata petraea F(2) population.

STREAM PERIPHYTON PHOTOACCLIMATION RESPONSE IN FIELD CONDITIONS: EFFECT OF COMMUNITY DEVELOPMENT AND SEASONAL CHANGES(1).

The photochemical behavior of intact stream periphyton communities in France was evaluated in response to the time course of natural light. Intact biofilms grown on glass substrata were collected at three development stages in July and November, and structural parameters of the biofilms were investigated (diatom density and taxonomy). At each season, physiological parameters based on pigment analysis (HPLC) and pulse-amplitude-modulated (PAM) chl fluorescence technique were estimated periodically during a day from dawn to zenith.

Cloning of hOST-PTP: the only example of a protein-tyrosine-phosphatase the function of which has been lost between rodent and human.

Protein-tyrosine-phosphatases (PTP-ases), in concert with protein tyrosine kinases, control various biological activities such as cell growth and differentiation. In rodents, around 40 PTP-ases have been described. Functional orthologue for each of these PTP-ases have been identified in human, except for OST-PTP.

Short-term associations between air pollution and respiratory drug sales.

Study Objective: This research was implemented to assess the effect of air pollution on anti-asthmatic, bronchodilator, and cough and cold preparation sales in the city of Rouen (France) based on the Upper Normandy Regional Union of Health Insurance Offices database and the Air Quality Monitoring Network database.

Design: An ecological time-series analysis was performed for a period of 2 years (July 1998-June 2000). Generalized additive model yields to relative risks and 95% confidence interval (CI) estimates were also carried out.

Segmental duplications in euchromatic regions of human chromosome 5: a source of evolutionary instability and transcriptional innovation.

Recent analyses of the structure of pericentromeric and subtelomeric regions have revealed that these particular regions of human chromosomes are often composed of blocks of duplicated genomic segments that have been associated with rapid evolutionary turnover among the genomes of closely related primates. In the present study, we show that euchromatic regions of human chromosome 5-5p14, 5p13, 5q13, 5q15-5q21-also display such an accumulation of segmental duplications. The structure, organization and evolution of those primate-specific sequences were studied in detail by combining in silico and comparative FISH analyses on human, chimpanzee, gorilla, orangutang, macaca, and capuchin chromosomes.

Birth of two chimeric genes in the Hominidae lineage.

How genes with newly characterized functions originate remains a fundamental question. PMCHL1 and PMCHL2, two chimeric genes derived from the melanin-concentrating hormone (MCH) gene, offer an opportunity to examine such an issue in the human lineage. Detailed structural, expression, and phylogenetic analysis showed that the PMCHL1 gene was created near 25 million years ago (Ma) by a complex mechanism of exon shuffling through retrotransposition of an antisense MCH messenger RNA coupled to de novo creation of splice sites.

Structure and expression of the variant melanin-concentrating hormone genes: only PMCHL1 is transcribed in the developing human brain and encodes a putative protein.

PMCHL1 and PMCHL2 are two copies of the so-called variant melanin-concentrating hormone (MCH) gene that are located, respectively, on human chromosome 5p14 and 5q13 and that emerged recently during primate evolution. They correspond to a 5'-end truncated version of the MCH gene mapped on chromosome 12q23 and encoding a neuropeptide precursor. The gene organization and regulation of the expression of the variant MCH genes in the human brain are the central issues we investigated.

Construction of a 1.2-Mb sequence-ready contig of chromosome 11q13 encompassing the multiple endocrine neoplasia type 1 (MEN1) gene. The European Consortium on MEN1.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant familial cancer syndrome characterized by parathyroid, pancreatic, and anterior pituitary tumors. The MEN1 locus has been previously localized to chromosome 11q13, and a 2-Mb gene-rich region flanked by D11S1883 and D11S449 has been defined. We have pursued studies to facilitate identification of the MEN1 gene by narrowing this critical region to a 900-kb interval between the VRF and D11S1783 loci through melotic mapping.

Fine mapping of the MLK-3 gene within 11q13 and its exclusion as the MEN1 susceptibility gene.

MLK-3 kinase is a widely expressed serine/ threonine kinase that bears multiple protein interaction domains and regulates signals mediated by the stress-responsive pathway. Thus, MLK-3 signaling affects numerous cellular processes, raising the possibility that MLK-3 might play a role in oncogenesis. In this report, we describe the fine mapping of the MLK-3 gene within the 11q13.

Framework YAC contig anchored into a 3.2-Mb high-resolution physical map in proximal 11q13.

Despite the presence on band q13 of chromosome 11 of a number of genes predisposing individuals to various human diseases, most of this genomic region remains loosely mapped. Moreover, there is a relative dearth of yeast artificial chromosome (YAC) contigs from genome-wide studies: YACs are irregularly distributed over this chromosomal region and have not been arranged into contigs. We have thus undertaken fine-scale mapping of a 3.

Mapping FRA11A, a folate-sensitive fragile site in human chromosome band 11q13.3.

FRA11A, a rare folate-sensitive fragile site assigned to 11q13.3, lies in an area of genomic instability associated with several diseases and amplification events. To map FRA11A, we used fluorescence in situ hybridization with yeast artificial chromosome and cosmid probes on metaphase chromosomes of patients expressing the fragile site.

Genetic testing in presymptomatic diagnosis of multiple endocrine neoplasia.

Multiple endocrine neoplasias (MEN) are familial diseases characterized by endocrine neoplasms and transmitted in an autosomal dominant manner. In MEN type 1, the major lesions affect parathyroid glands, pancreatic islet cells and anterior pituitary. The MEN-1 gene has been mapped to chromosome 11q13 and a set of DNA-polymorphic markers localized close to this region provides a useful tool for presymptomatic diagnosis in MEN-1 families.

Definition of the Minimal MEN1 Candidate Area Based on a 5-Mb Integrated Map of Proximal 11q13.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder with a high penetrance characterized by tumors of the parathyroid glands, the endocrine pancreas, and the anterior pituitary. The MEN1 gene, a putative tumor suppressor gene, has been mapped to a 3- to 8-cM region in chromosome 11q13 but it remains elusive as yet. We have combined the efforts and resources from four laboratories to form the European Consortium on MEN1 with the aims of establishing the genetic and the physical maps of 11q13 and of further narrowing the MEN1 region.

Definition of the minimal MEN1 candidate area based on a 5-Mb integrated map of proximal 11q13. The European Consortium on Men1, (GENEM 1; Groupe d'Etude des Néoplasies Endocriniennes Multiples de type 1).

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder with a high penetrance characterized by tumors of the parathyroid glands, the endocrine pancreas, and the anterior pituitary. The MEN1 gene, a putative tumor suppressor gene, has been mapped to a 3- to 8-cM region in chromosome 11q13 but it remains elusive as yet. We have combined the efforts and resources from four laboratories to form the European Consortium on MEN1 with the aims of establishing the genetic and the physical maps of 11q13 and of further narrowing the MEN1 region.