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To assess the role of cdc42 during neurite development, cmyc-tagged constitutively active (CA) and dominant negative (DN) cdc42 were expressed in dissociated primary chick spinal cord neurons using adenoviral-mediated gene transfer. Three days after in- fection, >85% of the neurons in infected cultures ex- pressed cdc42 proteins, as detected by indirect immuno- fluorescence against cmyc. Growth cones of infected neurons displayed 1.83- (CAcdc42) and 1.93-fold (DNcdc42) higher cmyc immunofluorescence per square micrometer than uninfected controls. CAcdc42 expres- sion stimulated growth cones, almost doubling growth cone size and number of filopodia, and increased neurite growth rates by 65- 89%. In neurons plated onto fi- bronectin, the percent of growth cones with both filop- odia and lamellipodia increased from 71 to 92%. Total Texas Red-phalloidin staining in these growth cones doubled, and the percent of growth cones with F-actin localized to peripheral regions increased from 52% in controls to 78% after CAcdc42 expression. Expression of DNcdc42 did not significantly alter growth cone mor- phology or neurite growth rates. Addition of soluble laminin to spinal cord neurons resulted in the identical phenotype as CAcdc42 expression, including changes in growth cone morphology, F-actin localization, and neu- rite growth rates. Significantly, expression of DNcdc42 blocked the effects of laminin on growth cones. These results show that cdc42 promotes neurite outgrowth and filopodial and lamellipodial formation in growth cones and suggests that cdc42 and laminin share a common signaling pathway during neurite development. Addi- tion of laminin to CAcdc42-expressing neurons is inhib- itory to growth cones, indicating that laminin also may activate some other pathways. © 2000 John Wiley & Sons, Inc.

The progenies of rice plants (Oryza sativa L.) differentiated from calli that had been cryopreserved and from control (non-cryopreserved) calli were used to study the influence of selection pressure during cryopreservation. The phenotypic evaluation of these progenies was based mainly on the response of seedlings and calli to freezing stress and on the characterization of protoplast and cell populations by flow cytometric analyses. The patterns of response to freezing stress, as well as the variations in some morphological and physiological cell parameters, were unrelated to the origin (cryopreserved or control calli) of the parental plants.

The use of cryoprotectants and slow cooling rates are routine procedures for the cryopreservation of plant cell lines. However, our results with rice (Oryza sativa L., cv. Taipei 309) show that calli can be cryopreserved by direct immersion and stored in liquid nitrogen without any cryoprotection. The efficiency of recovery using this method, as well as a conventional method was generally increased with a previous abscisic acid (ABA) treatment. Following cryopreservation, calli demonstrated some differences with respect to unfrozen calli of the same lines. Thus, resistance to freezing stress (−20°C for 2 h) increased significantly in all lines tested, irrespective of their pre-incubation with ABA. Calli that had been directly stored in liquid nitrogen also demonstrated a higher competence for genetic transformation than their unfrozen counterparts, as indicated by the transient gene expression levels obtained after particle bombardment. These differences might lead to further biotechnological applications. A genetic analysis of amplified DNA polymorphisms was performed with three independent lines that had been subjected to four combinations of ABA treatment and direct immersion in liquid nitrogen. At the loci screened with the randomly amplified polymorphic DNA (RAPD) markers tested, the genetic variations among lines and among calli of the same line akppear to be more related to tissue-culture-induced somaclonal variation than to cryoselection.

We conducted laboratory tests with six species of plants to determine their ability to remove benzene, trichloroethylene (TCE) and toluene from air. The objective of this proof-of-principal study was to evaluate the idea that phytoremediation techniques might be used to lower the concentrations of indoor air pollutants, such as volatile or semi-volatile organic compounds. Plants were exposed to the pollutants singly or in mixtures in an airtight chamber, and concentrations of the pollutants in the chamber were monitored through time to assess plant effects on the pollutants. In several experiments, we measured air temperature and CO2, as well. Lower surfaces of leaves of several of the species we tested were also examined by scanning electron microscopy to determine stomate abundance and size, and to provide information about leaf-surface elemental composition (by X-ray emission spectroscopy). Several of the species demonstrated an extensive ability to remove benzene from air. Gas chromatography methods allowed a reasonably direct, continuous monitoring of the kinetics and overall efficiency of the pollutant-removal process. We found that pollutant removal efficiency varied in response to plant species and the pollutant. Of the pollutants tested, benzene was most efficiently removed from air by Pelargonium domesticum, Ficus elastica and Chlorophytum comosum. Kalanchoe blossfeldiana, a common ornamental plant, appeared to take up benzene selectively over toluene, and TCE was removed efficiently from the air by C. comosum. Pentane, sometimes used as an internal standard in GC/MS, was removed from air by at least four of the species. For C. comosum, TCE appeared to lower the removal rates of benzene and pentane. Low-vacuum scanning electron microscopy provided information on stomate size and density and permitted rapid initial elemental analysis of the plant-leaf surface by X-ray emission spectroscopy. Our results indicate that simple tests for pollutant uptake, morphological and chemical features of plants, and plant detoxification enzyme activity might be used in multivariate fashion to identify plant species capable of removing volatile or semi-volatile pollutants from air.

Ischemia and reperfusion causes tissue injury that can be partially prevented by mild hypothermia. In this study we postulated that hypothermic protection could occur if imposed only during reperfusion. Rabbit ears were partially amputated, the central artery occluded for 6 h followed by reperfusion at an ambient temperature of either 20 or 24 degrees C resulting in ischemic ear temperatures of 22.5 vs. 24.7 degrees C. Ear temperature of rabbits remaining in the 24 degrees C room increased with reperfusion to 32.4 degrees C whereas those moved to the 20 degrees C room increased to 30.0 degrees C by 2 h of reperfusion. Ear volume was used as a measure of tissue edema and was measured for 7 days after the ears were allowed to reperfuse. Normalized myeloperoxidase content (polymorphonuclear cell accumulation) was significantly greater in the 24 degrees C ischemia-24 degrees C reperfusion group compared with the other groups. Ear edema was significantly less in the two groups exposed to 20 degrees C reperfusion compared with the 24 degrees C ischemia-24 degrees C reperfusion group. Peak ear volume was 5.0 times baseline for the 24 degrees C ischemia-24 degrees C reperfusion, 4.0 times baseline for the 20 degrees C ischemia-24 degrees C reperfusion, 3.4 times baseline for the 24 degrees C ischemia-20 degrees C reperfusion, and 3.3 times baseline for the 20 degrees C ischemia-20 degrees C group. We conclude that mild hypothermia reduces PMN accumulation and is more effective in preventing tissue injury when imposed during reperfusion compared with during ischemia.

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Hand rearing of neonates is a common practice for the propagation of psittacines. However, nutritional requirements for their growth and development are not well understood, and malnutrition is common. We analysed the amino acid (AA) profile of the crop contents of 19 free-living scarlet macaw (Ara macao) chicks, 19-59 days old. Predicted metabolizable energy (PME) density was 16.9 MJ/kg DM and true protein (total AA protein) 8.3 g/MJ PME. Crude protein (CP) was 10.0 g/MJ PME, lower than the requirements of 0- to 12-week-old leghorn chicks but not different than the requirements of growing budgerigars (Melopsittacus undulatus) and lovebirds (Agapornis spp.). The mean concentrations of leucine, isoleucine, threonine, lysine (Lys) and methionine on a PME basis were below the minimum requirements of 0- to 12-week-old leghorn-type chicks. The calculated PME density of the samples did not vary with age. However, there was a significant negative correlation between the average age of the chicks and the Lys concentration. We conclude that the lower CP and AA densities compared with poultry could result from a combination of (i) differences in the essential AA composition of the body tissues, (ii) adaptations that allow the birds to grow on low-protein food sources and (iii) suboptimal nutrition of these free-ranging chicks.

To ensure the delivery of safe animal products to consumers, withdrawal times (WDT) of drugs must be respected. Drugs administered in therapies can also reach nonedible tissues (for humans) such as feathers; this transfer is of concern as feather meal is used in diets of food producing animals, being this a possible source of residue contamination of final products for human consumption. WDTs of three flumequine formulations (10%, 80% premix powder and 20% solution) as well as the transfer of this drug into feathers were determined. One hundred and twenty broiler chickens were allocated into four experimental groups (36 birds each). Three of them were treated with 24 mg/kg bw orally for five consecutive days of each flumequine formulation, whereas one group remained untreated (12 birds as control group). After the treatment ended, six chickens of each experimental group and two controls were slaughtered daily for 6 days. Samples of muscle, liver and feathers were collected and analyzed by liquid chromatography tandem mass spectrometry (LC MS/MS). The WDTs showed differences between formulations. Flumequine concentrations found in feathers remained high during WDT and after this period, thus suggesting that the WDTs estimated for the pharmaceutical formulation of flumequine do not guarantee the absence of this drug in chicken nonedible tissues such as feathers.

Two groups of laying hens (each n=12) were administered 10 mg/kg enrofloxacin (ENRO) (group A) or 26.6 mg/kg flumequine (FLU) (group B) by gastric catheter daily for five consecutive days. A third group (n=6) was untreated controls. Eggs were collected from day one of treatment and up to 30 days after withdrawal of the drug. Egg white and yolk from each egg were separated, and ENRO, its metabolite ciprofloxacin (CIP) and FLU residues were analysed by a high-performance liquid chromatography method with fluorescence detection. The sum of ENRO and CIP was detectable in egg white on the first day of treatment in high-level concentrations (2007.7 μg/kg) and remained steady during administration. In egg yolk, residues were detectable at day one in lower concentrations (324.4 μg/kg), increasing to the end of treatment. After treatment, these residues decreased and were detectable up to day 8 in egg white, and day 10 in yolk. FLU residues during drug administration in white were detectable in high concentrations from day one to five (6788.4-6525.9 μg/kg), and in yolk, concentrations were lower during administration (629.6-853.9 μg/kg). After drug withdrawal, FLU residues remained longer in egg white (30 days) than in yolk (26 days). For both drugs, differences of concentrations between matrices were significant.

To ensure delivery of safe animal products to consumers, the withdrawal time (WDT) of drugs must be respected. Property differences among pharmaceutical formulations, for the same drugs, can lead to differences in the WDTs estimation. The WDTs of four commercial formulations of enrofloxacin (ENRO) in broiler chickens, considering MRLs established by different countries, were studied. Two hundred-thirty-four broiler chicks were allotted among four groups; the formulations were orally administered daily with 10 mg/kg bw. After treatment, six chickens of each group and two controls were slaughtered daily until day 9 post-treatment. Samples of muscle and liver were collected, and analyzed using HPLC-MS-MS. The WDTs among formulations of ENRO showed differences of 24 and 48 h. Based on the European Community and Chile MRLs of 100 microg/kg (muscle) and 200 microg/kg (liver), the WDTs did not exceed 5 days. When Japan MRL was considered (10 microg/kg(,)), the WDTs increased up to 8 days. These results indicate that for WDTs determination, the differences among pharmaceutical formulations of a drug must be considered as well as the MRLs.

We have determined the electrochemical behavior of a series of long chain 1-alkyl-3-methylimidazolium ionic liquids [(R-mim)BF 4 ], with alkyl groups ranging from pentyl to octyl, and tested them as electrolytes in lithium ion batteries. These ionic liquids present good conductivities and electrochemical windows which make them likely solvents of choice for Li-ion batteries using LiMn 2 O 4 as the cathode. Charge/discharge properties of a Li/ R-mim)BF 4 /LiMn 2 O 4 cell have been evaluated both with the IL as the sole electrolyte and with IL and conducting support. The Li- ion insertion results in IL can be explained on the basis of self aggregation of each long chain 1-alkyl-3-methylimidazolium cation. INTRODUCTION It is well known that progress in lithium-ion batteries relies much on improvements in the electrolyte. Ionic liquids (IL) have become a viable alternative as electrolytes for these devices [1]. In general, the most common electrolytes for Li-ion batteries are a mixture of 1:1 EC/EMC (ethylene carbonate and ethyl methyl carbonate) and LiPF

The unicellular rhodophyte, Porphyridium cruentum, and the filamentous cyanobacterium, Calothrix sp. PCC 7601, contain phycobiliproteins that have covalently bound phycobilin chromophores. Overnight incubation of solvent-extracted cells at 40 degrees C with methanol liberates free phycobilins that are derived from the protein-bound bilins by methanolytic cleavage of the thioether linkages between bilin and apoprotein. Two of the free bilins were identified as 3(E)-phycocyanobilin and 3(E)-phycoerythrombilin by comparative spectrophotometry and high pressure liquid chromatography. Methanolysis also yields a third bilin free acid whose absorption and 1H NMR spectra support the assignment of the 3(E)-phytochromobilin structure. This novel bilin is the major pigment isolated from cells that are pre-extracted with acetone-containing solvents. Since phytochrome- or phytochromobilin-containing proteins are not present in either organism, the 3(E)-phytochromobilin must arise by oxidation of phycobilin chromophores. This pigment is not obtained by similar treatment of a cyanobacterium and a rhodophyte that lack phycoerythrin. Therefore, 3(E)-phytochromobilin appears to be derived from phycoerythrobilin-containing proteins. Comparative CD spectroscopy of 3(E)-phytochrombilin and 3(E)-phycocyanobilin suggests that the two bilins share the R stereochemistry at the 2-position in the reduced pyrrole ring. Incubation of 2(R),3(E)-phytochromobilin with recombinant oat apophytochrome yields a covalent bilin adduct that is photoactive and spectrally indistinguishable from native oat phytochrome isolated from etiolated seedlings. These results establish that the phycobiliprotein-derived 2(R),3(E)-phytochromobilin is a biologically active phytochrome chromophore precursor.

An enzyme extract from the phycocyanin-containing unicellular rhodophyte, Cyanidium caldarium, reductively transforms biliverdin IX alpha to phycocyanobilin, the chromophore of phycocyanin, in the presence of NADPH. Unpurified cell extract forms both 3(E)-phycocyanobilin, which is identical to the major pigment that is released from phycocyanin by methanolysis, and 3(Z)-phycocyanobilin, which is obtained as a minor methanolysis product. After removal of low molecular weight material from the cell extract, only 3(Z)-phycocyanobilin is formed. 3(E)-Phycocyanobilin formation from biliverdin IX alpha, and the ability to isomerize 3(Z)-phycocyanobilin to 3(E)-phycocyanobilin, are reconstituted by the addition of glutathione to the incubation mixture. Partially purified protein fractions derived from the initial enzyme extract form 3(Z)-phycocyanobilin plus two additional, violet colored bilins, upon incubation with NADPH and biliverdin IX alpha. Further purified protein fractions produce only the violet colored bilins from biliverdin IX alpha. One of these bilins was identified as 3(Z)-phycoerythrobilin by comparative spectrophotometry, reverse-phase high pressure liquid chromatography, and 1H NMR spectroscopy. A C. caldarium protein fraction catalyzes the conversion of 3(Z)-phycoerythrobilin to 3(Z)-phycocyanobilin. This fraction also catalyzes the conversion of 3(E)-phycoerythrobilin to 3(E)-phycocyanobilin. The conversion of phycoerythrobilins to phycocyanobilins requires neither biliverdin nor NADPH. The synthesis of phycoerythrobilin and its conversion to phycocyanobilin by extracts of C. caldarium, a species that does not contain phycoerythrin, indicates that phycoerythrobilin is a biosynthetic precursor to phycocyanobilin. The enzymatic conversion of the ethylidine group from the Z to the E configuration suggests that the E-isomer is the precursor to the protein-bound chromophore.

Cell-free extract of the unicellular rhodophyte, Cyanidium caldarium catalyzes enzymatic reduction of biliverdin IX alpha to phycocyanobilin, the chromophore of the light-harvesting phycobiliprotein, phycocyanin. The enzyme activity is soluble, and the required reductant is NADPH. The extract has been separated into three protein fractions, all of which are required to reconstitute biliverdin reduction. One fraction contains ferredoxin, which was identified by its absorption spectrum. This fraction could be replaced with commercial ferredoxin derived from spinach or the red alga, Porphyra umbilicalis. The second protein fraction contains ferredoxin-NADP+ reductase, which was identified by the ability to catalyze ferredoxin-dependent reduction of cytochrome c in the presence of NADPH. This fraction could be replaced with commercial spinach ferredoxin-NADP+ reductase. These two components appear to be identical to previously described components of the algal heme oxygenase system that catalyzes biliverdin IX alpha formation from protoheme in C. caldarium extracts. The third protein fraction, in the presence of the first two (or their commercial counterparts) plus NADPH, catalyzes the reduction of biliverdin IX alpha to phycocyanobilin. The results indicate that the transformation of biliverdin to phycocyanobilin catalyzed by C. caldarium extracts is a ferredoxin-linked reduction process. The results also suggest the possibility that heme oxygenation and biliverdin reduction may occur in C. caldarium on associated enzyme systems.

A partially purified protein fraction from the phycocyanin-containing unicellular rhodophyte, Cyanidium caldarium, reductively transforms biliverdin IX alpha to a violet colored bilin in the presence of NADPH, ferredoxin, and ferredoxin-NADP+ reductase. This bilin has a violin-like absorption spectrum with maxima at 335 and 560 nm in methanolic HCl and at 337, 567, and 603-604 nm in CHCl3. The bilin has been determined to be 15,16-dihydrobiliverdin IX alpha by comparative spectrophotometry and 1H NMR spectroscopy. This product of biliverdin IX alpha reduction is converted enzymatically to phycobilins by further reduction. A general biosynthetic pathway is proposed which accounts for the formation of the phycobilins from biliverdin IX alpha by a two-step reduction process followed by isomerization.

The impact of a single seizure on cognition remains controversial. We hypothesized that a single early-life seizure (sELS) on rat Postnatal Day (P) 7 would alter only hippocampus-dependent learning and memory in mature (P60) rats. The Morris water maze, the novel object and novel place recognition tasks, and contextual fear conditioning were used to assess learning and memory associated with hippocampus/prefrontal cortex, perirhinal/hippocampal cortex, and amygdala function, respectively. The elevated plus maze and open-field test were used to assess anxiety associated with the septum. We report that sELS impaired hippocampus-dependent short-term memory, but not spatial learning or recall. sELS did not disrupt performance in the novel object and novel place recognition tasks. Contextual fear conditioning performance suggested intact amydgala function. sELS did not change anxiety levels as measured by the elevated plus maze or open-field test. Our data suggest that the long-term cognitive impact of sELS is limited largely to the hippocampus/prefrontal cortex.

The aim of this work was to study the effect of the application of a solid waste from olive oil production (alperujo) on the movement and persistence of the herbicide diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea]. The application of alperujo, fresh or composted, to the land has been shown to be an extremely effective contribution to increasing crop yields and to maintaining or improving soil fertility. An experimental olive grove located in Mengibar (Jaen, Spain) was divided into two plots: 1. Plot without organic amendment (blank) and 2. Plot treated with alperujo during 3 years at a rate of 17920 kg of alperujo ha. Diuron was applied to both plots at a rate of 2 kg haa.i. Triplicates from each plot were sampled at three depths (0-10, 10-20 and 20-30 cm), air-dried, remains of olive leaves, grass roots, and stones removed and sieved through a 5 mm mesh sieve. Diuron was extracted with methanol 1:2 weight:volume ratio, the extracts were evaporated to dryness, resuspended in 2 mL of methanol, filtered and analyzed by HPLC. Higher amounts of diuron were detected at each sampling depth in plots treated with alperujo. The increase in soil organic matter content upon amendment with alperujo slightly increased sorption, suggesting that other factors beside sorption affect diuron degradation rate in organic amended soils.

This paper proposes a non-invasive optical scrambling technique to secure optical transmissions at high data rates (>10Gb/s). The proposed method belongs to the optical code-division multiple access (OCDMA) technique, using spectral phase encoding, based on overlapping of adjacent scrambled/spread pulses to encrypt transmitted data. In our system, data confidentiality is directly related to scrambled/spread pulse interference, avoiding direct detection by a power detector, in contrast to network access application (OCDMA), where this overlapping should be avoided. Our goal is to secure data transmission without impacting the physical layer, by guaranteeing the optical transparency of the encryption technique with respect to conventional transmission equipments. Therefore, we simulated the system penalty as a function of the transmission distance for a bit error rate (BER) target of 10-9 to estimate the impact of the linear and non-linear transmission effects on our encryption technique. We consider a point-to-point span for mono-channel and multi-channel setups where self-phase modulation (SPM) and cross-phase modulation (XPM) become significant. In the last section, we discuss the resilience of our encryption technique to some realistic attack scenarios. The eavesdropper can use the linear optical sampling (LOS) technique, which with coherence conditions on the waveform under test, permits to extract the amplitude and the phase of each spectral compound, enabling, to determinate the phase filter used to encrypt. Determining the necessary time to crack the mask allows us to establish the mask refreshment to guarantee data confidentiality.

Novel ruthenium (II) complexes were prepared containing 2-phenyl-1,8-naphthyridine derivatives. The coordination modes of these ligands were modified by addition of coordinating solvents such as water into the ethanolic reaction media. Under these conditions 1,8-naphthyridine (napy) moieties act as monodentade ligands forming unusual [Ru(CO)2Cl2(η1-2-phenyl-1,8-naphthyridine-kN)(η1-2-phenyl-1,8-naphthyridine-kN′)] complexes. The reaction was reproducible when different 2-phenyl-1,8-naphthyridine derivatives were used. On the other hand, when dry ethanol was used as the solvent we obtained complexes with napy moieties acting as a chelating ligand. The structures proposed for these complexes were supported by NMR spectra, and the presence of two ligands in the [Ru(CO)2Cl2(η1-2-phenyl-1,8-naphthyridine-kN)(η1-2-phenyl-1,8-naphthyridine-kN′)] type complexes was confirmed using elemental analysis. All complexes were tested as catalysts in the hydroformylation of styrene showing moderate activity in N,N′-dimethylformamide. Copyright © 2008 John Wiley & Sons, Ltd.

The purpose of this prospective study was to compare two different milk preparation methods to assay for the presence of Mycobacterium bovis by PCR. Detection by a C 18 -carboxypropylbetaine (CB-18)-based sample processing method was compared to extraction of DNA from milk with glass beads. Samples from 17 skin test-positive cattle were analyzed. Following CB-18 processing and glass bead extraction, the sensitivity of IS 6110 -based PCR was 94.1 and 58.8%, respectively ( P < 0.025). Because CB-18 processing will permit the proficient use of PCR for diagnosis and surveillance of bovine tuberculosis, it will contribute to the more efficient detection and control of tuberculosis.

In this paper, we propose an energy-based feedback control scheduling framework for power-aware soft real-time tasks executing in dynamic environments, where real-time parameters are not known a priori. We propose the use of a controller based on an energy savings ratio, which allows higher energy savings when higher missed deadlines are allowed to occur. The scheduler uses the energy feedback to calculate the amount of workload to be adjusted and provides the input for a variable voltage optimization algorithm (VVA). The VVA algorithm is a greedy algorithm that adjusts the workload to optimize power consumption by computing a near optimal solution for the tasks's voltage/speed selection problem. Extensive sets of tests are executed to simulate the performance of our energy feedback scheduling power-aware architecture under overload and underload conditions. Simulation results show that the proposed architecture is capable of handling real-time tasks with unknown arrivals and execution times, and derive a system in which power savings are maximized.

En este artículo se dan a conocer documentos que certifican la presencia en Madrid del pintor Francisco de Herrera el Viejo en 1647 y 1648. Además, se aportan importantes novedades acerca del retablo de San Basilio, de Sevilla: las medidas de su arquitectura; el retraso en casi diez años de su instalación y pago al pintor; y, sobre todo, las tres pinturas localizadas - un Niño Jesús, de la puerta del sagrario y los retratos de San Basilio el Mayor y de Santa Eumelia, padres de San Basilio - que continúan insertas en un fragmento del retablo original. Documents are presented here attesting to the presence of the painter Francisco de Herrera el Viejo in Madrid between 1647 and 1648. Likewise, important new information concerning the altarpiece of San Basilio in Seville is brought to light: the measurements of the architectural structure, the delay of almost ten years in its installation and payment to the artist; and, above all, the three paintings now located – a Christ Child from the door of the ciborium, and the portraits of Saint Basil the Great and Saint Eumelia, parents of Saint Basil – still attached to a fragment of the original alterpiece.

The antimicrobial susceptibility of 94 Salmonella strains isolated from different poultry farms in Chile (broiler and laggin hens) were analyzed by the dilution plates method. Thirty-nine of them were resistant to flumequine, nalidixic acid and oxolinic acid with MIC values higher than 64 microg/ml. These quinolone resistant strains were analyzed in order to determine the presence of mutations in the QRDR region of gyrA gene by AS-PCR-RFLP analysis. 51.3% of the strains showed mutations at codon Ser 83 and 41.0% showed mutations at codon Asp 87. No mutations were observed on codon Gly 81. These mutations were confirmed by sequenciation of one representative strain from different RFLP pattern. Likewise, no double mutations were observed. Over 90% of the quinolone resistant strains presented mutations at the QRDR region of the gyrA gene. Three phenotypically resistant strains did not show any mutations on the QRDR region of gyrA gene. However, other molecular resistant mechanism could be involve. This is the first study that demonstrate the emergency of quinolone and fluoroquinolone resistance in Chilean Salmonella strains isolated from poultry thus indicating the requirement of monitoring programmes in veterinary medicine.

We have studied the quasielastic 3He(e,e(')p)2H reaction in perpendicular coplanar kinematics, with the energy and the momentum transferred by the electron fixed at 840 MeV and 1502 MeV/c, respectively. The 3He(e,e(')p)2H cross section was measured for missing momenta up to 1000 MeV/c, while the A(TL) asymmetry was extracted for missing momenta up to 660 MeV/c. For missing momenta up to 150 MeV/c, the cross section is described by variational calculations using modern 3He wave functions. For missing momenta from 150 to 750 MeV/c, strong final-state interaction effects are observed. Near 1000 MeV/c, the experimental cross section is more than an order of magnitude larger than predicted by available theories. The A(TL) asymmetry displays characteristic features of broken factorization with a structure that is similar to that generated by available models.

Pericarditis complicating cardiac trauma and resulting in tamponade is uncommon. Possible causes include an autoimmune reaction or an inflammatory response to blood entering the pericardium. We present two patients, one with effusive and one with constrictive pericarditis occurring within 2 weeks of a penetrating trauma close to but not directly involving the heart. These cases illustrate the importance of clinical suspicion and aggressive management in the diagnosis and management of such patients.

[1] Balloon-borne observations of frost-point temperature and ozone in the equatorial western, central and eastern Pacific as well as over equatorial eastern Brazil provide a highly accurate data set of water vapor across the tropical tropopause. Data were obtained at San Cristobal, Galapagos, Ecuador (0.9°S, 89.6°W), during the late northern winter and the late northern summer in 1998 and 1999 and at Juazeiro do Norte, Brazil (7.2°S, 39.3°W), in February and November 1997. Earlier data in the western Pacific region in March 1993 were reanalyzed to extend the scope of the observations. The data show three different circumstances in which saturation or supersaturation occurs and imply different mechanisms for dehydration at the tropical tropopause: (1) convective dehydration, (2) slow-ascent dehydration, and (3) large-scale wave-driven dehydration. Furthermore, air that crosses the tropical tropopause in the late northern summer may be dehydrated further during late northern fall, as the average tropical tropopause rises and cools. Not all soundings show dehydration, and there are clear differences in the frequency and depth of saturation in different regions and seasons. The tropopause transition region can be identified in accurate measurements of relative humidity, even under conditions where ozone observations are ambiguous. Deep convection plays an important role in setting up this transition region, which is then subject to large-scale wave activity and wave breaking at the tropopause or midlatitude intrusions. High relative humidities over regions of strong subsidence show that descending motion in the troposphere is limited to levels below the transition region.

Organoclays were assayed as matrices in which to associate herbicides, with the aim of decreasing product losses that could give rise to water contamination from agricultural activities. Fenuron was selected as model of a very mobile and highly water-soluble herbicide. Two different organoclays of high (A-HDT) and low (H-C18) reversible fenuron sorption were selected. Herbicide-organoclay complexes were prepared from the two organoclays and with two different fenuron contents (20 and 40 g AI kg-1) and two different mixing times, so as to form a series of weak and strong complexes. The release of fenuron from those complexes into water and water/soil suspensions gave values of T50 (time to release 50% of the fenuron content) ranging from 0.3 min to 2400 h. The total fenuron released in these closed systems ranged from 48 to 80% of the fenuron in the complex. The organoclay type (high or low sorptivity) had the greatest influence on fenuron release, followed by the strong or weak complex, suggesting that herbicide-organoclay interactions are the main factors controlling release. Soil column leaching experiments showed fenuron-organoclay complexes to be effective in reducing the peak herbicide concentration in the leachate to a half (6 microns) or a quarter (3 microns) of that obtained from the free technical compound (12 microns). Herbicide lost through leaching was reduced from 78% for the free technical fenuron to 50-30%, depending on the organoclay used as carrier and the strength of the complex. Bioassay with ryegrass showed that the weak fenuron/H-C18 complex (40 g AI kg-1) gave the same herbicidal activity as technical fenuron. The potential suitability of low-sorptive organoclays for conferring slow-release properties on the fenuron complex has been demonstrated.

To assess the role of cdc42 during neurite development, cmyc-tagged constitutively active (CA) and dominant negative (DN) cdc42 were expressed in dissociated primary chick spinal cord neurons using adenoviral-mediated gene transfer. Three days after infection,85% of the neurons in infected cultures expressed cdc42 proteins, as detected by indirect immunofluorescence against cmyc. Growth cones of infected neurons displayed 1.83- (CAcdc42) and 1.93-fold (DNcdc42) higher cmyc immunofluorescence per square micrometer than uninfected controls. CAcdc42 expression stimulated growth cones, almost doubling growth cone size and number of filopodia, and increased neurite growth rates by 65-89%. In neurons plated onto fibronectin, the percent of growth cones with both filopodia and lamellipodia increased from 71 to 92%. Total Texas Red-phalloidin staining in these growth cones doubled, and the percent of growth cones with F-actin localized to peripheral regions increased from 52% in controls to 78% after CAcdc42 expression. Expression of DNcdc42 did not significantly alter growth cone morphology or neurite growth rates. Addition of soluble laminin to spinal cord neurons resulted in the identical phenotype as CAcdc42 expression, including changes in growth cone morphology, F-actin localization, and neurite growth rates. Significantly, expression of DNcdc42 blocked the effects of laminin on growth cones. These results show that cdc42 promotes neurite outgrowth and filopodial and lamellipodial formation in growth cones and suggests that cdc42 and laminin share a common signaling pathway during neurite development. Addition of laminin to CAcdc42-expressing neurons is inhibitory to growth cones, indicating that laminin also may activate some other pathways.

Endothelial cell death may contribute to tissue injury from ischemia. Little is known, however, about the characteristics of endothelial cell death in response to hypoxia. Using an in vitro model, we found that human umbilical vein endothelial cells were resistant to hypoxia-induced cell death with only a 2% reduction in viability at 24 h and 45% reduction in viability at 48 h. Overexpression of a mutant, IkappaBalpha, via adenoviral vector did not potentiate cell death in hypoxia, indicating that nuclear factor-kappaB activation was not involved in cytoprotection. Cell death in hypoxia was determined to be apoptotic by 3' labeling of DNA using terminal deoxynucleotidyl transferase staining and reversibility of cell death with a caspase inhibitor. Exposure of endothelial cells to hypoxia did not alter levels of proapoptotic and antiapoptotic Bcl-2 family members Bax and Bcl-XL by immunoblot analysis. In contrast, changes in p53 protein levels correlated with the induction of apoptosis in hypoxic endothelial cells. Inhibition of the proteasome increased p53 protein levels and accelerated cell death in hypoxia. Overexpression of p53 by adenoviral transduction was sufficient to initiate apoptosis of normoxic endothelial cells. These data provide a framework for the study of factors regulating endothelial cell survival and death in hypoxia.

Research efforts dealing with the parameters and processes affecting the transport of herbicides in soils are needed in order to prevent further damage of surface and groundwater reserves. The present study was designed to improve the knowledge of the terbacil behaviour in soils by integrating adsorption/desorption and mobility experiments as related to soil characteristics. Hand-packed soil columns were used for the mobility experiments and simultaneously the sorption of terbacil was examined by the batch procedure. Four soils were used: two clay soil, a sandy clay soil and a sandy soil. The sorption parameters from Freundlich equation showed weak sorption, although it was higher and partially irreversible in the clay soils. The herbicide was found very mobile in the sandy soils and mobile in the clay soils with a leachate herbicide recovery ranging from 100 to 87% for the sandy and clay soils respectively. The elution profile and cumulative curves showed differences among the soils related to organic matter and clay contents and the combined influence of sorption (adsorption/desorption) and degradation processes are suggested. The mobility index calculated from the residue distribution along the soil column showed that terbacil mobility was inversely related with soil organic matter and with soil clay content, being highly correlated with the soil water flow, which also relates to the soil texture.

Publisher Summary Adsorption is the controlling step that helps in the formation of microaggregates, as well as in the transport of nutrients and pollutants along the soil profile in many soils. Adsorption on soil colloids depends on the nature and properties of the surfaces available for interaction with ions and molecules present in the soil solution. Active sites on soil clays are masked by the presence of hydrous oxide material coating their surfaces and much of these surface particles are coated by humic substances. Thus, the complex soil colloids show surface properties attributable to clay, hydrous oxide, and humic compounds. These types of associations are present in soils to different extents. Residual products from the transformation of animal and plant remains as well as the products of the microbial degradation of organic materials added to soils as amendments are the origin of the naturally occurring components of the soil organic matter acting as component of soil aggregates. Humic substances (HS) and soil polysaccharides are the main active components of soil organic matter, which interact with the soil inorganic components in the formation of the organomineral complex as a base of the soil aggregates.

The bonding strengths between a wide range of mortars to tiles, bricks and a hardened cement paste were determined. These were related to the porosities, measured by mercury porosimetry, of the component materials. Both the porosity and the composition of the mortars affected the bonding strengths. However, the pore size distribution rather than total pore volume was found to be of greater importance in determining the bonding strength.

The clinical heterogeneity of Diabetes Mellitus (DM) is also evident during the gestational period and thus, pregnancy could be complicated by a previously diagnosed DM or by diabetes that is first diagnosed during pregnancy (gestational diabetes or gestational alteration of the oral glucose tolerance test according with the degree of hyperglycemia). Independently of the stage at time of maternal diagnosis, the conceptus is at greater risk (probably since the time of conception) for abortion, genetic malformations, perinatal metabolic complications and death; these risks are apparently directly related with the time at diagnosis, duration and degree of metabolic alteration on the mother (mainly hyperglycemia) and the adaptive mechanisms on the product (hyperinsulinemia). Retrospectively, 412 pregnancies complicated with any type of carbohydrate metabolism alteration were studied in our service. The results demonstrated a high frequency of Gestational diabetes (42.2%) and of type II diabetes (35.9%); there was a good agreement with previous reports regarding the personal and family histories in the patients already known diabetic before pregnancy. The types of obstetric complications were similar to previous reports, but some of them with a greater frequency in our patients, namely hydramnios, toxemia, and urinary tract infection, and ketoacidosis with a minor frequency. We also observed an increased frequency of congenital malformations on the products. On the other hand, the metabolic complications of the newborn were similar to other reports with a slight predominance on the babies of known diabetic mothers prior to gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

A partially purified protein fraction from the phycocyanin-containing unicellular rhodophyte, Cyanidium caldarium, reductively transforms biliverdin IX alpha to a violet colored bilin in the presence of NADPH, ferredoxin, and ferredoxin-NADP+ reductase. This bilin has a violin-like absorption spectrum with maxima at 335 and 560 nm in methanolic HCl and at 337, 567, and 603-604 nm in CHCl3. The bilin has been determined to be 15,16-dihydrobiliverdin IX alpha by comparative spectrophotometry and 1H NMR spectroscopy. This product of biliverdin IX alpha reduction is converted enzymatically to phycobilins by further reduction. A general biosynthetic pathway is proposed which accounts for the formation of the phycobilins from biliverdin IX alpha by a two-step reduction process followed by isomerization.

Cell-free extract of the unicellular rhodophyte, Cyanidium caldarium catalyzes enzymatic reduction of biliverdin IX alpha to phycocyanobilin, the chromophore of the light-harvesting phycobiliprotein, phycocyanin. The enzyme activity is soluble, and the required reductant is NADPH. The extract has been separated into three protein fractions, all of which are required to reconstitute biliverdin reduction. One fraction contains ferredoxin, which was identified by its absorption spectrum. This fraction could be replaced with commercial ferredoxin derived from spinach or the red alga, Porphyra umbilicalis. The second protein fraction contains ferredoxin-NADP+ reductase, which was identified by the ability to catalyze ferredoxin-dependent reduction of cytochrome c in the presence of NADPH. This fraction could be replaced with commercial spinach ferredoxin-NADP+ reductase. These two components appear to be identical to previously described components of the algal heme oxygenase system that catalyzes biliverdin IX alpha formation from protoheme in C. caldarium extracts. The third protein fraction, in the presence of the first two (or their commercial counterparts) plus NADPH, catalyzes the reduction of biliverdin IX alpha to phycocyanobilin. The results indicate that the transformation of biliverdin to phycocyanobilin catalyzed by C. caldarium extracts is a ferredoxin-linked reduction process. The results also suggest the possibility that heme oxygenation and biliverdin reduction may occur in C. caldarium on associated enzyme systems.

An enzyme extract from the phycocyanin-containing unicellular rhodophyte, Cyanidium caldarium, reductively transforms biliverdin IX alpha to phycocyanobilin, the chromophore of phycocyanin, in the presence of NADPH. Unpurified cell extract forms both 3(E)-phycocyanobilin, which is identical to the major pigment that is released from phycocyanin by methanolysis, and 3(Z)-phycocyanobilin, which is obtained as a minor methanolysis product. After removal of low molecular weight material from the cell extract, only 3(Z)-phycocyanobilin is formed. 3(E)-Phycocyanobilin formation from biliverdin IX alpha, and the ability to isomerize 3(Z)-phycocyanobilin to 3(E)-phycocyanobilin, are reconstituted by the addition of glutathione to the incubation mixture. Partially purified protein fractions derived from the initial enzyme extract form 3(Z)-phycocyanobilin plus two additional, violet colored bilins, upon incubation with NADPH and biliverdin IX alpha. Further purified protein fractions produce only the violet colored bilins from biliverdin IX alpha. One of these bilins was identified as 3(Z)-phycoerythrobilin by comparative spectrophotometry, reverse-phase high pressure liquid chromatography, and 1H NMR spectroscopy. A C. caldarium protein fraction catalyzes the conversion of 3(Z)-phycoerythrobilin to 3(Z)-phycocyanobilin. This fraction also catalyzes the conversion of 3(E)-phycoerythrobilin to 3(E)-phycocyanobilin. The conversion of phycoerythrobilins to phycocyanobilins requires neither biliverdin nor NADPH. The synthesis of phycoerythrobilin and its conversion to phycocyanobilin by extracts of C. caldarium, a species that does not contain phycoerythrin, indicates that phycoerythrobilin is a biosynthetic precursor to phycocyanobilin. The enzymatic conversion of the ethylidine group from the Z to the E configuration suggests that the E-isomer is the precursor to the protein-bound chromophore.

9 páginas, 1 figura, 4 tablas, 22 referencias, The adsorption of 2,4‐D has been studied obtaining adsorption isotherms on 22 soils by the batch equilibration technique. Fitting the adsorption data to the Freundlich equation three adsorption capacity were calculated at low (Kf or Cs 1), medium (Cs4.5) and high (Cs 30) 2,4‐D concentration. The adsorption capacity and intensity factors obtained in this study resulted in according with those reported by other authors. From the simple regression analysis between adsorption capacities and soil properties it was shown that organic matter and free iron contents of soils favoured the adsorption, whereas pH, surface area and clay content decreased the adsorption of 2,4‐D. By dividing the soils according to their clay mineralogy it was shown that the soils properties determining the adsorption capacity were different for soils with phyllosilicates as essential clay components than for soils with iron oxides as major clay components., This research was supported by the Junta de Andalucía and the Dirección General de Investigación Científica y Técnica (Project Nº PB87-0240).

This study included 15 women 18-36 years old with primary or secondary amenorrhea, low FSH and LH, a negative response to clormadinone and serum prolactin (Prl) levels less than 20.0 ng/ml. The following tests were performed on alternate days: LH and FSH determinations every 20 minutes (pulses) during 2-4 hours (n = 15); LH and FSH response to a single dose of GnRH 100 micrograms IV (n = 15) and after administration of 100 micrograms IM of GnRH daily during four consecutive days (n = 7); TRH test 200 micrograms IV (n = 9); oral metoclopramide-Prl induced response (10 mg) (n = 2); one to three basal determinations of cortisol, estradiol (E2), T3, T4, and TSH (n = 15). All patients had serum E2 levels less than 10.0 pg/ml and none showed a regular LH or FSH pulsatility. In seven patients (group A) serum LH had a 10-30 fold increase above basal levels in response to GnRH, while the other eight patients (group B) showed no response at all; serum FSH changes were most irregular in both group. In group A no other hormonal deficiencies were detected, while in group B only three patients had an isolated LH-FSH deficiency, and in the other five this deficiency was accompanied by Prl, TSH, and/or ACTH lack. The present results suggest that: 1) group A represents isolated GnRH deficiency and the amenorrhea has hypothalamic etiology; 2) group B had LH-FSH deficiency of pituitary origin, in most cases associated to other pituitary hormone deficiencies; 3) the lack of LH response to an initial single dose of GnRH is not an absolute indicator of hypophyseal amenorrhea.