The PINHEAD/ZWILLE gene acts pleiotropically in Arabidopsis development and has overlapping functions with the ARGONAUTE1 gene.

Several lines of evidence indicate that the adaxial leaf domain possesses a unique competence to form shoot apical meristems. Factors required for this competence are expected to cause a defect in shoot apical meristem formation when inactivated and to be expressed or active preferentially in the adaxial leaf domain. PINHEAD, a member of a family of proteins that includes the translation factor eIF2C, is required for reliable formation of primary and axillary shoot apical meristems.

The human copper-zinc superoxide dismutase gene (SOD1) proximal promoter is regulated by Sp1, Egr-1, and WT1 via non-canonical binding sites.

Human copper-zinc superoxide dismutase (Cu,Zn-SOD) participates in the control of reactive oxygen intermediate intracellular concentration. In this study, we show that phorbol 12-myristate 13-acetate (PMA) increases Cu,Zn-SOD mRNA expression within 30 min. The sequence between nucleotides -71 and -29 is essential for both basal and PMA-induced gene expression.

A putative kinetic model for substrate metabolisation by Drosophila acetylcholinesterase.

Insect acetylcholinesterase, an enzyme whose catalytic site is located at the bottom of a gorge, can metabolise its substrate in a wide range of concentrations (from 1 microM to 200 mM) since it is activated at low substrate concentrations. It also presents inhibition at high substrate concentrations. Among the various rival kinetic models tested to analyse the kinetic behaviour of the enzyme, the simplest able to explain all the experimental data suggests that there are two sites for substrate molecules on the protein.

The arabidopsis thaliana AGRAVITROPIC 1 gene encodes a component of the polar-auxin-transport efflux carrier.

Auxins are plant hormones that mediate many aspects of plant growth and development. In higher plants, auxins are polarly transported from sites of synthesis in the shoot apex to their sites of action in the basal regions of shoots and in roots. Polar auxin transport is an important aspect of auxin functions and is mediated by cellular influx and efflux carriers.

Mutations in Arabidopsis thaliana genes involved in the tryptophan biosynthesis pathway affect root waving on tilted agar surfaces.

Arabidopsis thaliana roots grow in a wavy pattern upon a slanted surface. A novel mutation in the anthranilate synthase alpha 1 (ASA1) gene, named trp5-2wvc1, and mutations in the tryptophan synthase alpha and beta 1 genes (trp3-1 and trp2-1, respectively) confer a compressed root wave phenotype on tilted agar surfaces. When trp5-2wvc1 seedlings are grown on media supplemented with anthranilate metabolites, their roots wave like wild type.

Enzymes hydrolyzing organophosphates as potential catalytic scavengers against organophosphate poisoning.

Enzymes hydrolyzing organophosphates could be used as catalytic scavengers for treatment of organophosphate poisoning and for decontamination. Two organophosphorus hydrolases (OPH) were selected: the Flavobacterium sp/Pseudomonas diminuta phosphotriesterase (PTE) and human paraoxonase (HuPON). Genes encoding these enzymes were cloned and functional recombinant enzymes expressed.

Absence of a protective effect of the oxime 2-PAM toward paraoxon-poisoned honey bees: acetylcholinesterase reactivation not at fault.

We investigated the failure of 2-PAM to protect honey bees against poisoning with paraoxon. The protective effect of the oxime 2-PAM against inhibition of acetylcholinesterase (AChE) by paraoxon was estimated in vitro and in vivo and was correlated with the mortality of paraoxon-treated bees. In vitro, 2-PAM protected 90% of AChE activity in the presence of paraoxon and reactivated more than 90% of inhibited AChE.

[Mortality, morbidity and short-term neurologic outcome of premature infants less than or equal to 32 weeks gestational age in Fort-de-France CHR].

Unlabelled: The mortality and neurodevelopmental outcome of premature infants born between 25 and 33 weeks of gestational age in Fort-de-France (Martinique, French West Indies) is reported.

Population: The preterm cohort included 214 infants born during the years 1992 to 1995.

Results: The mortality rate during the hospitalization was 20%, but was only 14% when the birth weight was more than 1,000 g.

Resistance of butyrylcholinesterase to inactivation by ultrasound: effects of ultrasound on catalytic activity and subunit association.

The effects of 20 kHz ultrasound on catalytic activity and structure of the tetramer of wild-type human butyrylcholinesterase (BChE) from plasma and recombinant D70G mutant enzyme were studied at constant temperature. Effects on catalytic properties of both enzymes were investigated by kinetic analysis under ultrasound irradiation using a neutral substrate (o-nitrophenylbutyrate), a positively charged substrate (butyrylthiocholine), and a negatively charged substrate (aspirin). Effects on structure of highly purified wild-type BChE were followed by gel electrophoresis and activity measurements at Vmax after ultrasound treatment.

Butyrylcholinesterase-catalysed hydrolysis of aspirin, a negatively charged ester, and aspirin-related neutral esters.

Although aspirin (acetylsalicylic acid) is negatively charged, it is hydrolysed by butyrylcholinesterase (BuChE). Catalytic parameters were determined in 100 mM Tris buffer, pH 7.4, in the presence and absence of metal cations.

Acute Q fever pneumonia: a review of 80 hospitalized patients.

Study Objectives: To emphasize epidemiologic, clinical, or radiologic characteristics whose detection could lead to an early diagnosis and to enhance therapeutic efficacy.

Patients: Eighty hospitalized patients from 1982 to 1996.

Design: The diagnosis of Q fever infection was serologically confirmed in all the patients (phase II Coxiella burnetii antibody) using the complement fixation test and/or the indirect immunofluorescence antibody test.

Purification, molecular characterization and catalytic properties of a Pseudomonas fluorescens enzyme having cholinesterase-like activity.

An enzyme with a cholinesterase (ChE) activity, produced by Pseudomonas fluorescens, was purified to homogeneity in a three-step procedure. Analysis by non-denaturing and SDS-PAGE, and by isoelectric focusing, indicated that the enzyme was a monomer of 43 kDa, with a pI of 6.1.

Two invertebrate acetylcholinesterases show activation followed by inhibition with substrate concentration.

In vertebrates there are two cholinesterases, with differences in catalytic behaviour with respect to substrate concentration: butyrylcholinesterase displays an increased activity at low substrate concentrations, whereas acetylcholinesterase displays inhibition by excess substrate. In two invertebrates, Drosophila melanogaster and Caenorhabditis elegans, we found cholinesterases that showed both kinetic complexities: substrate activation at low substrate concentrations followed by inhibition at higher concentrations. These triphasic kinetics can be explained by the presence of two enzymes with different kinetic behaviours or more probably by the existence of a single enzyme regulated by the substrate concentration.

Particle counting assay for anti-toxoplasma IgG antibodies. Comparison with four automated commercial enzyme-linked immunoassays.

An assay for anti-toxoplasma IgG antibodies based on agglutination of latex particles was set up and compared with commercial immunoassays. The reaction was measured by instrumental counting of particles remaining unagglutinated. The running time was 45 min.

Aging of di-isopropyl-phosphorylated human butyrylcholinesterase.

Organophosphate-inhibited cholinesterases can be reactivated by nucleophilic compounds. Sometimes phosphylated (phosphorylated or phosphonylated) cholinesterases become progressively refractory to reactivation; this can result from different reactions. The most frequent process, termed 'aging', involves the dealkylation of an alkoxy group on the phosphyl moiety through a carbocation mechanism.

Combined pressure/heat-induced inactivation of butyrylcholinesterase.

The combined effects of pressure and temperature on the activity of butyrylcholinesterase (BuChE) were investigated in the pressure range from 10(-3) to 5 kbar and temperature range from -10 degrees C to 70 degrees C. Inactivation of the enzyme showed a complex dependence on pressure and temperature. Under moderate pressures (1-3 kbar) at temperatures 40-65 degrees C BuChE was resistant to heat inactivation; under other conditions of pressure and temperature, the action of both parameters was synergistic and caused inactivation.

Importance of aspartate-70 in organophosphate inhibition, oxime re-activation and aging of human butyrylcholinesterase.

Asp-70 is the defining amino acid in the peripheral anionic site of human butyrylcholinesterase (BuChE), whereas acetylcholinesterase has several additional amino acids, the most important one being Trp-277 (Trp-279 in Torpedo AChE). We studied mutants D70G, D70K and A277W to evaluate the role of Asp-70 and Trp-277 in reactions with organophosphates. We found that Asp-70 was important for binding positively charged echothiophate, but not neutral paraoxon and iso-OMPA.

Tumour marker CA 50 levels compared to signs and symptoms in the diagnosis of pancreatic cancer.

The diagnostic merits of CA 50 and of symptoms indicating pancreatic cancer (pain, jaundice, weight loss, malabsorption) were compared prospectively in 512 consecutive patients. Among the final diagnoses were: exocrine pancreatic cancer, 175; periampullary cancer, 44; other gastrointestinal cancer, 45; and chronic pancreatitis, 64 cases. The suspected diagnoses based on symptoms and signs were correct in 80% of the patients with exocrine pancreatic cancer, in 78% with periampullary, in 76% with other gastrointestinal cancer and in 90% with chronic pancreatitis.

Role of aspartate 70 and tryptophan 82 in binding of succinyldithiocholine to human butyrylcholinesterase.

The atypical variant of human butyrylcholinesterase has Gly in place of Asp 70. Patients with this D70G mutation respond abnormally to the muscle relaxant succinyldicholine, experiencing hours of apnea rather than the intended 3 min. Asp 70 is at the rim of the active site gorge 12 A from the active site Ser 198.

A single amino acid substitution, Gly117His, confers phosphotriesterase (organophosphorus acid anhydride hydrolase) activity on human butyrylcholinesterase.

The G117H mutant of human butyrylcholinesterase (EC 3.1.1.

Thallium in French agrosystems--I. Thallium contents in arable soils.

The thallium (Tl) content of the upper horizons of 244 French soils was determined as the first step towards the creation of a reference data bank for total Tl content of arable soils. Forty soil samples were collected in the vicinity of potential anthropogenic sources of Tl, but the remainder came from rural areas. The distribution of Tl concentrations in soils was characterized by a median value of 0.

Thallium in French agrosystems-II. Concentration of thallium in field-grown rape and some other plant species.

The aim of this study was to assess thallium (Tl) uptake into the aerial parts of selected crop species grown on French soils with high Tl content of pedogeochemical origin (0.3-40 mg Tl kg(-1) on a dry wt (DW) basis). Husked wheat and maize grains contained less than 4 microg Tl kg(-1) DW, but rape shoots accumulated Tl with a shoot-soil partition coefficient (PC) > 1, and rape seeds had PC > 3.

Collaborative development of a sun protection factor test method: a proposed European Standard. COLIPA Task Force 'Sun Protection Measurement', Europe.

Synopsis Standardization of the method to determine sun protection factors (SPF) is fundamental to uniform labelling of SPF values on sun products. The COLIPA Task Force 'Sun Protection Measurement'(SPM), including representatives of major European sun-product manufacturers and contract testing laboratories, was established in 1990 to define methods for sun products testing. The process involved in developing the COLlPA SPF Test Method started with a critical appraisal of previously existing methods, and identification of areas for improvement.