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International audience; We present a theoretical investigation of terahertz (THz) generation in laser-induced gas plasmas. The work is strongly motivated by recent experimental results on micro-plasmas, but our general findings are not limited to such a configuration. The electrons and ions are created by tunnel-ionization of neutral atoms, and the resulting plasma is heated by collisions. Electrons are driven by electromagnetic, convective and diffusive sources and produce a macroscopic current which is responsible for THz emission. The model naturally includes both, ionization current and transition-Cherenkov mechanisms for THz emission, which are usually investigated separately in the literature. The latter mechanism is shown to dominate for single-color multi-cycle lasers pulses, where the observed THz radiation originates from longitudinal electron currents. However, we find that the often discussed oscillations at the plasma frequency do not contribute to the THz emission spectrum. In order to predict the scaling of the conversion efficiency with pulse energy and focusing conditions, we propose a simplified description that is in excellent agreement with rigorous particle-in-cell simulations.

In the muon ( g - 2 ) experiment at Brookhaven National Laboratory, the spin precession frequency ω a is obtained from a standard χ 2 minimization fit applied to the time distribution of decay electrons. The unusually high accuracy ( ∼ 0.5 ppm ) of the experiment puts stringent requirements on the quality of the fit and the level of understanding of the statistical properties of the fitted parameters. We discuss the properties of the fits and their implications on the derived value for ω a , including estimates of the effect of an imperfect fit function, methods of including additional external information to reduce the error, the effects of splitting the data into many smaller subsets of data, applying different weighting methods to the data using energy information, and various tests of data suitability.

Resume Le dosage de l’iode urinaire ne fait plus partie du bilan de base de l’exploration des sujets hyperthyroidiens, remplace par les dosages hormonaux et la scintigraphie. En utilisant une methode colorimetrique sur microplaques, nous avons cherche a montrer que ce dosage pouvait presenter un interet dans le diagnostic differentiel de certaines pathologies. Nous avons montre que les concentrations de l’iode urinaire ne sont pas differentes entre euthyroidiens et sujets presentant une maladie de Basedow. Chez les sujets avec une thyroidite subaigue virale ou auto-immune, l’iode urinaire est multiplie par 3 et par 10 pour les patients presentant une surcharge iodee. Dans les thyroidites, l’iodurie est maximale au moment de la poussee aigue et le suivi des concentrations permet d’evaluer l’atteinte du tissu thyroidien et l’efficacite therapeutique.

The experimental method together with the analysis method and results of the data taken in 2000 and prospects of the muon anomalous magnetic and electric dipole moment experiments are presented here., 12 pages, 20 figures. Proceedings of my plenary talk at ICHEP02, Amsterdam, 31 July 2002

The measurement of the (g−2) value of leptons provides a unique test of theory since it is the only quantity (unlike charge and mass) calculable in the framework of the Standard Model of elementary particles. The muon (g−2) experiment E821 is currently in progress at Brookhaven National Laboratory. Four data taking runs for positive muons and one run for negative muons were successfully accomplished in 1997–2000 and 2001, respectively. Results of the 1997–2000 runs have been published, thus completing our experiment for μ+. Data analysis for the 2001 run for μ− is currently in progress. To provide measurement of \(a_\mu = \tfrac{1} {2}(g - 2)_{\mu ^ - }\) at the same level of accuracy as for \(a_{\mu ^ + } = \tfrac{1} {2}(g - 2)_{\mu ^ + }\), we need to have one more data taking run.

Hormonal changes, substrate mobilization and energy metabolism were studied inturbot Scophthalmus maximus exposed to 3 hypoxic conditions (oxygen partial pressure in water,PwO 2 = 90, 60 and 30 mm Hg) followed by recovery under normoxia. Measurements of the blood pH,total CO 2 concentration, arterial oxygen partial pressure, hematocrit, glucose, lactate, and ‘stress’hormones (cortisol, adrenaline and noradrenaline) plasmatic concentrations were performed. High-energy phosphorylated compounds, glycogen, glucose and lactate concentrations were also deter-mined in liver and white muscle tissues. Exposure to 90 or 60 mm Hg did not induce any majorphysiological change, as hyperventilation by itself could compensate for the decrease in wateroxygen tension. At 30 mm Hg, marked increases in cortisol, adrenaline and noradrenaline concen-trations, associated with a decrease in blood arterial oxygen partial pressure, were observed. Duringexposure to 30 mm Hg, turbot resorted to anaerobic metabolism, resulting in liver glycogen depletionand lactate production. This mechanism appeared to be efficient enough to produce energy, as nosignificant change in phosphorylated compounds and adenylate energy charges in muscle and livercould be observed. These results indicate an absence of metabolic depression in turbot downto 30 mm Hg and confirm the high capacity of this species to cope with low water oxygen tension.KEY WORDS: Hypoxia · Anaerobiosis · Catecholamines · Cortisol · Lactate · Turbot

L’efficacite de la coloscopie, principal examen de diagnostic et de depistage des affections coliques, depend etroitement de la qualite de la preparation. Les facteurs influencant l’efficacite de cette preparation sont divers (experience de l’operateur, action du produit prescrit pour la preparation, acceptabilite et observance des modalites de la preparation par le patient).

L'Adour (drainant 17 000 km2 sur la facade atlantique, exploites par la peche amateur et la peche professionnelle) est frequente par six grands migrateurs amphihalins : saumon atlantique, truite de mer, anguille, grande alose, alose feinte et lamproie marine, tous plus ou moins en voie de regression au debut des annees 1980. Au cours des deux dernieres decennies, des actions diverses (amenagements du milieu, etudes, repeuplements, mesures reglementaires) ont ete menees pour leur restauration. Ces actions ont pu etre conduites grâce a des concours financiers (Etat, Region, Agence de l'Eau, Europe) et a la participation des pecheurs regroupes au sein de l'association MIGRADOUR, avec l'appui technique du Conseil Superieur de la Peche. La presente communication fait le point sur chacune de ces especes, conformement a un plan d'expose en trois parties : etat initial (avant 1980), actions menees de 1980 a 1998 et bilan et, orientation actuelle.

Resume Les adenocarcinomes mammaires s'accompagnent frequemment de localisation metastatiques osseuses. La determination urinaire de marqueurs specifiques de la resorption osseuse a ete decrite dans le diagnostic et le suivi de ces metastases. Le Crosslaps (TM) , produit de degradation de l'extremite C-terminale du telopeptide du collagene de type I, fait partie de ces marqueurs. Cependant le recueil des urines reste toujours delicat et la mesure au niveau serique est preferable. En utilisant une methode immunoenzymatique pour le dosage serique du Crosslaps (TM) , nous avons compare chez 45 femmes presentant un cancer du sein, les concentrations de ce marqueur au niveau serique (S-CTX) et urinaire (CTX). Comme pour le CTX, les concentrations en S-CTX sont plus elevees chez les femmes avec metastases. Les variations du S-CTX sont un bon reflet de l'efficacite de la chimiotherapie. Cependant, compare a l'imagerie, le S-CTX a la meme specificite que le CTX (96 %) mais une sensibilite plus faible (81 % versus 95 % pour le CTX).

Multiple myeloma causes extensive bone remodeling. Classical biochemical markers such as urinary calcium have poor sensitivity for detecting multiple myeloma bone remodeling. New biochemicals have been developed including a carboxyterminal telopeptide of collagen I (CTX). We used an immunoenzymatic assay to determine urinary CTX in 60 patients with multiple myeloma. This marker was evaluated with regard to total pyridinolines, urinary calcium, radiological features, pain and response to treatment with bisphosphonates. In patients with bone involvement, CTX concentrations were significantly higher (+230%) than those of deoxypyridinoline (DPD) (+175%) and pyridinolines (PYD) (+130%). In all patients we have found a close correlation between CTX and DPD but not between CTX and PYD. Compared to radiological features, CTX was more sensitive (97%) and specific (96%) than DPD. After treatment by bisphosphonates, the fall in CTX concentrations was paralleled to urinary calcium and more marked than pyridinolines. Although our results need to be confirmed, CTX appears to be a potential marker to explore bone involvement in multiple myeloma.

In modern medicine the undeniable value and indispensability of scientific investigations are now universally recognized both for diagnostic purposes and monitoring of disease and in basic epidemiology. The direct treatment of patients is an undeniable task of doctors in medicine. Progress in laboratory science is largely the result of contributions by scientists with an adequate education and specialisation in the field, i.e. by clinical chemists. Clinical laboratory science has developed on a broad front throughout the European Community, resulting in significant differences in what constitutes a national clinical chemistry service in each state. Clinical chemistry is the medical discipline devoted to obtain, explore and employ chemical knowledge and chemical methods of investigation, in order to procure knowledge about normal and abnormal chemical processes in man. These processes are studied on a general level, in order to get insight into human health and disease, and on a patient-specific level for diagnostic or monitoring purposes. The delimitation of clinical chemistry varies from country to country, since there is no sharp boundary to haematology, immunology, molecular biology and microbiology. One of the main tasks of the clinical chemist is direction and supervision of a laboratory department in a hospital or health service (public or private), where his role involves bridging the gap between rapidly developing laboratory science and technology and the growing knowledge on characteristics of disease. He must possess fundamental biochemical knowledge and have the ability to use this knowledge most appropriately as applied to clinical requirements, i.e. diagnosis of disease and planning and monitoring of therapy. Apart from providing a competent laboratory service, the clinical chemist must be able to function as a consultant to his clinical colleagues and liaise with them in the interpretation of laboratory results. His advice and professional consultation have at least three aspects, i.e. choosing the most appropriate laboratory investigation in a certain case, ensuring that the analyses are performed in the best possible way and correctly reported and, finally, providing information and (most important) interpretation on the significance and consequences of the laboratory data obtained. As the results of laboratory investigations and the consultation of the clinical chemist have a direct and important influence on the treatment of the patient, it is to the benefit of the public that the profession of the clinical chemist is duly regulated.

resume Les adenocarcinomes mammaires s'accompagnent, dans environ un tiers des cas, de localisations metastatiques osseuses de nature osteoclastique. La scintigraphie osseuse aux biphosphonates marques au 99m Tc reste la methode de reference pour depister et localiser ces metastases. Recemment, divers marqueurs biochimiques sont apparus, qui permettent une etude du remodelage osseux. Le Crosslaps ™ , produit de degradation de l'extremite C-terminale du telopeptide du collagene de type I, fait partie de ces marqueurs. En utilisant une methode immuno-enzymatique, nous avons pu mettre en evidence chez 50 patients une bonne correlation entre l'aspect scintigraphique et la concentration urinaire en Crosslaps ™ . Le suivi de ces patients pendant leurs cures de chimiotherapie nous a permis de montrer qu'un dosage regulier du Crosslaps ™ est un bon reflet de l'evolution des metastases et de l'efficacite therapeutique.

Ugine a decide en 1991 la construction d’une nouvelle unite de production d’acier inoxydable lamine a froid en Thailande.Apres la description du projet et des principales etapes de la construction, des phases de mise en route et de la montee en puissance, nous exposons les facteurs cles de cette reussite. En respectant le delai initial et le budget de 184 millions de US$, la pleine capacite de 5 000 t/mois (60 000 t/an) a ete atteinte en novembre 1994, soit 34 mois apres le debut des travaux sur un terrain vierge.

Three-dimensional optical recording by laser-induced fluorescent silver clusters is demonstrated in glass. The fluorescence properties of these stable clusters can be altered, depending on the glass recording exposure conditions. A "Blu-ray"-like drive enables readout of the information inside the glass without cross-talk and photobleaching. This original recording medium can provide an answer to the societal problem of long-term high-density data storage.

It is not understood why only some infections with Entamoeba histolytica result in disease. The calcium-regulated transcription factor upstream regulatory element 3-binding protein (URE3-BP) was initially identified by virtue of its role in regulating the expression of two amebic virulence genes, the Gal/GalNac lectin and ferredoxin. Here we tested whether this transcription factor has a broader role in regulating virulence. A comparison of in vivo to in vitro parasite gene expression demonstrated that 39% of in vivo regulated transcripts contained the URE3 motif recognized by URE3-BP, compared to 23% of all promoters (P < 0.0001). Amebae induced to express a dominant positive mutant form of URE3-BP had an increase in an elongated morphology (30% ± 6% versus 14% ± 5%; P = 0.001), a 2-fold competitive advantage at invading the intestinal epithelium (P = 0.017), and a 3-fold increase in liver abscess size (0.1 ± 0.1 g versus 0.036 ± 0.1 g; P = 0.03). These results support a role for URE3-BP in virulence regulation., IMPORTANCE Amebic dysentery and liver abscess are caused by Entamoeba histolytica. Amebae colonize the colon and cause disease by invading the intestinal epithelium. However, only one in five E. histolytica infections leads to disease. The factors that govern the transition from colonization to invasion are not understood. The transcription factor upstream regulatory element 3-binding protein (URE3-BP) is a calcium-responding regulator of the E. histolytica Gal/GalNAc lectin and ferredoxin genes, both implicated in virulence. Here we discovered that inducible expression of URE3-BP changed trophozoite morphology and promoted parasite invasion in the colon and liver. These results indicate that one determinant of virulence is transcriptional regulation by URE3-BP.

Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muon, as well as the combined result, d=-0.1(0.9)E-19 e-cm, are all consistent with zero, we set a new muon EDM limit, |d| < 1.9E-19 e-cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM., 19 pages, 15 figures, 7 tables

In liver and serum, AST activity is dependent on two isoenzymes, which are mitochondrial and cytosolic in nature. In an attempt to explain the well-known increase of serum mitochondrial AST-to-total AST ratio in chronic alcoholism (which is due to a specific increase of the mitochondrial isoenzyme), we analyzed: (a) liver and serum AST, ALT and glutamate dehydrogenase activities in 23 active drinkers with minimal liver changes, 11 alcoholic patients with cirrhosis who had stopped drinking, 18 nonalcoholic patients with viral chronic hepatitis and 11 subjects with normal livers; and (b) the expression of messenger RNAs for AST isoenzymes in the corresponding liver samples. Enzymatic activities were decreased in the liver irrespective of the origin of the liver disease. In patients with viral chronic hepatitis (or in those with alcoholic cirrhosis when abstinent), variations in liver proteins and messenger RNAs paralleled significant decreases in mitochondrial AST, ALT and glutamate dehydrogenase and a nonsignificant decrease of cytosolic AST. In alcoholic patients with minimal liver changes, the significant decrease of hepatic cytosolic AST, ALT and glutamate dehydrogenase activities contrasted with a close-to-normal liver mitochondrial AST activity; the increased amounts of mitochondrial AST messenger RNA give evidence for a pretranslational mechanism of regulation, indicating a possible increase in the total production of mitochondrial AST in the liver. The decrease of hepatic cytosolic AST activity was statistically significant only in alcoholic patients without cirrhosis who had a normal cytosolic AST mRNA level, thus suggesting a contributory role of translational or posttranslational regulation. In conclusion, regulation of AST isozymes during liver disease is complex, including differential, pretranslational and translational or posttranslational mechanisms. (HEPATOLOGY 1991;14:620–625.)

The spin precession frequency of muons stored in the $(g-2)$ storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero $\Delta\omega_{a}$ (=$\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}$); and a sidereal variation of $\omega_{a}^{\mu^{\pm}}$. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: $b_{Z} =-(1.0 \pm 1.1)\times 10^{-23}$ GeV; $(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23})$ GeV; and the 95% confidence level limits $\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24}$ GeV and $\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24}$ GeV., Comment: 5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestions

Human cytosolic aspartate aminotransferase (cAspAT) cDNA clones have been isolated from an adult human liver cDNA library. Among the clones, two cDNAs of 1,550 and 1,950 base pairs, respectively, have been characterized. These two cDNAs differ only in the lengths of their 3{prime} noncoding regions and by the presence of one or two putative polyadenylation signals AATAAA. Northern blot analysis revealed two different mRNAs of 2.1 and 1.8 kbp in several human tissues, whereas Southern blot analysis suggested the existence of a single gene for the human cAspAT. The two mRNA species result from the alternative use of two polyadenylation signals. In the liver, the relative ratio of these mRNAs varies among different species and, in humans at least, during development. The properties of the two mRNAs were compared. The half-lives of the 2.1 and 1.8 kbp mRNAs, in the HepG2 cell line, are 8 and 12 h, respectively. The two mRNAs have similar and rather short poly(A) tracts of 20-50 nucleotides. Both mRNAs are capable of directing the in vitro synthesis of the cAspAT protein. The authors conclude that both the 2.1 and 1.8 kbp cAspAT mRNAs are functional and exhibit similar properties.

The promoter of the gene coding for the rat cytosolic aspartate aminotransferase was cloned from a Charon 4A genomic library. We have sequenced a 1.1-kilobase PstI-PstI fragment which contains the first exon of the gene, the beginning of the first intron and 682 base pairs of the 5' regulatory region (+1 being the A of the first ATG codon), which exhibits promoter activity. The promoter region is G + C rich, does not include any TATA-like element, but has 4 putative Sp1-binding sites and 6 regularly spaced CCAAT boxes. The promoter activity of the 5' regulatory region, as well as its sensitivity to glucocorticoids, were assessed by transient gene expression assays after fusion to the chloramphenicol acetyltransferase gene in the hepatoma cell lines HepG2 and Fao. Multiple transcription start sites were found on the gene over a short distance (55 base pairs), but they were differentially regulated by glucocorticoids as determined by both primer extension analysis and S1 mapping. In particular, transcription from 2 start sites was increased 15- to 18-fold, whereas transcription from the 3 other ones was increased 3-fold. In addition, three new start sites, below the detection limit in control cells, were highly induced. Therefore, a hormonal regulatory element can discriminate among closely related transcription start sites.

We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a(mu)=(g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples of positive and negative muons, were used to deduce a(mu)(Expt)=11659208.0(5.4)(3.3)x10(-10), where the statistical and systematic uncertainties are given, respectively. The combined uncertainty of 0.54 ppm represents a 14-fold improvement compared to previous measurements at CERN. The standard model value for a(mu) includes contributions from virtual QED, weak, and hadronic processes. While the QED processes account for most of the anomaly, the largest theoretical uncertainty, approximate to 0.55 ppm, is associated with first-order hadronic vacuum polarization. Present standard model evaluations, based on e(+)e(-) hadronic cross sections, lie 2.2-2.7 standard deviations below the experimental result.

In tropical countries. vitamin A deficiency is one of the most important dietary deficiencies. Its monitoring usually involves analysis of retinol after venipuncture with some difficulties (disease transmission, religious belief). Sample collection on Dried Blood Spot (DBS) is less invasive and safer. Sample storage is easier. We developed a liquid chromatography method with electrochemical detection to measure DBS retinol. Retinol acetate was used as an internal standard. The method is linear up to 2.5 microM with a detection limit of 0.04 microM. Precision is below 10% and DBS retinol recovery overage is 90%. DBS retinol concentration decreased during 7 days after sampling, it is necessary to wait this delay before to determine vitamin A concentrations. In Congolese children DBS retinol measurement showed a severe vitamin A deficiency in 8% of them. This percentage is closely correlated with clinical parameters.

The measurement of iodine is a widely accepted method to explore iodine disorders. The most precise estimation is the determination of the urinary iodine in 24-hour collections. Urine collection is notoriously difficult to obtain, specially in children. In these conditions, serum measurement could be a method to overcome these limitations. We describe a colorimetric method adapted on a microtiter plate, with optimized serum mineralization conditions. The method is linear to 2400 nmol/L with a detection limit of 75 nmol/L. Precision is below 10%. The method was validated against one automatic technique. We conclude that this relatively simple method could be an additional tool to explore dysthyroidism.

The anomalous magnetic moment of the negative muon has been measured to a precision of 0.7 parts per million (ppm) at the Brookhaven Alternating Gradient Synchrotron. This result is based on data collected in 2001, and is over an order of magnitude more precise than the previous measurement of the negative muon. The result a_mu= 11 659 214(8)(3) \times 10^{-10} (0.7 ppm), where the first uncertainty is statistical and the second is sytematic, is consistend with previous measurements of the anomaly for the positive and negative muon. The average for the muon anomaly a_{mu}(exp) = 11 659 208(6) \times 10^{-10} (0.5ppm)., Comment: 4 pages, 4 figures, submitted to Physical Review Letters, revised to reflect referee comments. Text further revised to reflect additional referee comments and a corrected Fig. 3 replaces the older version

The magnetic moment anomaly a_mu = (g_mu - 2) / 2 of the positive muon has been measured at the Brookhaven Alternating Gradient Synchrotron with an uncertainty of 0.7 ppm. The new result, based on data taken in 2000, agrees well with previous measurements. Standard Model evaluations currently differ from the experimental result by 1.6 to 3.0 standard deviations., Comment: Talk presented at RADCOR - Loops and Legs 2002, Kloster Banz, Germany, September 8-13 2002, to be published in Nuclear Physics B (Proc. Suppl.); 5 pages, 3 figures

A higher precision measurement of the anomalous g value, a_mu = (g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron, based on data collected in the year 2000. The result a_{mu^+} = 11 659 204(7)(5) times 10^{-10} (0.7 ppm) is in good agreement with previous measurements and has an error about one half that of the combined previous data. The present world average experimental value is a_mu(exp) = 11 659 203(8) times 10^{-10} (0.7 ppm)., Comment: 5 pages, 4 figures. submitted to Physical Review Letters. as accepted for publication in Physical Review Letters. As accepted for publication in Physical Review Letters

The consequences of angina were assessed by a questionnaire completed by 1,528 out-hospital doctors (79% of general practitioners, 21% of cardiologists) on 3,654 patients. This population comprised 2,304 men (64%) and 1,282 women (36%) with a mean age of 69.5 years (men: 67.1, women: 73.8 years). Previous myocardial infarction was present in 36.6% of cases and the average number of angina attacks was 3.1 per month. Angina seemed to affect the social behaviour of 25 to 30% of patients, the affective behaviour of 40% of patients and everyday life style in 60% of cases. Sixty per cent of patients had difficulties in their work and 60% also had psychological consequences of the angina. The social consequences of angina were different according to the patient's gender. Women were more affected in family life and men in their affective behaviour. The psychological consequences were also different: women were more likely to be anxious or depressed whereas men were usually more irritable. The incidence of anxio-depressive reactions with age was not studied (the female population was older). The higher incidence of anxio-depressive symptoms in women may be partially explained by their age at the time of diagnosis and the difference in prognosis between men and women when coronary artery disease is established.

We have studied the expression and regulation of the rat testis cytosolic aspartate aminotransferase gene. The cytosolic aspartate aminotransferase activity was 5-fold lower in the testis than in the liver and kidney. A 1.9-kilobase mRNA form was detected in the rat testis in contrast to the 2.1- and 1.8-kilobase forms present in other organs. Using Northern blot and S1 mapping analyses, we found that the proximal polyadenylation site was almost exclusively used in the testis as opposed to other organs where the distal site was preferentially used. RNase protection and primer extension analysis showed that transcription was initiated at multiple sites in all organs, but the pattern of those start sites was different in the testis; in particular, a novel transcription start site was specifically detected in this organ (at position -115 from the translation start site). This site was first observed in 29-day-old rats and was maximally utilized in the adult testis. DNase I footprinting using testis nuclear extracts revealed the presence of three sites of DNA-protein interaction in the 250-base pair proximal promoter, a pattern similar to the one found using liver nuclear extracts. However, the proteins bound had different properties as shown by gel retardation experiments. We conclude that the pattern of transcription initiation and the polyadenylation site selection of a housekeeping gene can be tissue-specific.

The Entamoeba histolytica transcription factor Upstream Regulatory Element 3-Binding Protein (URE3-BP) is a calcium-responsive regulator of two E. histolytica virulence genes, hgl5 and fdx1. URE3-BP was previously identified by a yeast one-hybrid screen of E. histolytica proteins capable of binding to the sequence TATTCTATT (Upstream Regulatory Element 3 (URE3)) in the promoter regions of hgl5 and fdx1. In this work, precise definition of the consensus URE3 element was performed by electrophoretic mobility shift assays (EMSA) using base-substituted oligonucleotides, and the consensus motif validated using episomal reporter constructs. Transcriptome profiling of a strain induced to produce a dominant-positive URE3-BP was then used to identify additional genes regulated by URE3-BP. Fifty modulated transcripts were identified, and of these the EMSA defined motif T[atg]T[tc][cg]T[at][tgc][tg] was found in over half of the promoters (54% p, Author Summary Most infections with Entamoeba histolytica are asymptomatic. However, in a minority of cases, they develop into invasive and even life-threatening amebiasis. We suspect, based on prior studies of invasive amebae, that changes in amebic gene expression enable the transition from asymptomatic to invasive infection. Our long-term goal is to identify the genetic program required to cause amebic colitis. Here, we studied a transcription factor named URE3-BP that controls the expression of two virulence genes, the Galactose and Galactose N- acetyl- galactosamine inhibitable lectin (Gal/GalNAc lectin) and ferredoxin. We suspected that this factor might coordinate invasiveness by co-regulating additional virulence factors. The consensus DNA motif that is recognized by URE3-BP was identified by reporter gene assays and by electromobility shift assays. We then inducibly expressed a constitutively active form of the transcription factor, and measured the changes in total amebic gene expression mediated by overexpression of this dominant-positive version of URE3-BP. This analysis allowed for a further definition of the functional URE3 motif. Inducible expression of URE3-BP led to changes in the transcript levels of several novel amebic membrane proteins. In conclusion, this genome-wide analysis of a transcription factor and its cis-acting regulatory sequence in Entamoeba histolytica has identified new transcripts regulated by URE3-BP that may play a role in trophozoite motility within a coordinated virulence-specific gene regulatory network.

The promoter of the gene coding for the rat cytosolic aspartate aminotransferase was cloned from a Charon 4A genomic library. We have sequenced a 1.1-kilobase PstI-PstI fragment which contains the first exon of the gene, the beginning of the first intron and 682 base pairs of the 5' regulatory region (+1 being the A of the first ATG codon), which exhibits promoter activity. The promoter region is G + C rich, does not include any TATA-like element, but has 4 putative Sp1-binding sites and 6 regularly spaced CCAAT boxes. The promoter activity of the 5' regulatory region, as well as its sensitivity to glucocorticoids, were assessed by transient gene expression assays after fusion to the chloramphenicol acetyltransferase gene in the hepatoma cell lines HepG2 and Fao. Multiple transcription start sites were found on the gene over a short distance (55 base pairs), but they were differentially regulated by glucocorticoids as determined by both primer extension analysis and S1 mapping. In particular, transcription from 2 start sites was increased 15- to 18-fold, whereas transcription from the 3 other ones was increased 3-fold. In addition, three new start sites, below the detection limit in control cells, were highly induced. Therefore, a hormonal regulatory element can discriminate among closely related transcription start sites.