Photoinduced electron-transfer α-deoxygenation of aldonolactones. Efficient synthesis of 2-deoxy-d-arabino-hexono-1,4-lactone Bordoni, Andrea Veronica; Muchnik, Rosa; Marino, María Carla A photoinduced electron-transfer (PET) reaction was used for the deoxygenation at C-2 of aldonolactones derivatized as 2-O-[3-(trifluoromethyl)benzoyl] or benzoyl esters. By irradiation of different D-galactono- and D-glucono-1,4-derivatives, with a 450 W lamp, using 9-methylcarbazole as photosensitizer, the corresponding 2-deoxy-D-lyxo- and 2-deoxy-D-arabino-hexono-1,4-lactones were efficiently obtained.O-[3-(trifluoromethyl)benzoyl] or benzoyl esters. By irradiation of different D-galactono- and D-glucono-1,4-derivatives, with a 450 W lamp, using 9-methylcarbazole as photosensitizer, the corresponding 2-deoxy-D-lyxo- and 2-deoxy-D-arabino-hexono-1,4-lactones were efficiently obtained.D-lyxo- and 2-deoxy-D-arabino-hexono-1,4-lactones were efficiently obtained.

Sex-related differences in the gastrointestinal disposition of ivermectin in the rat: P-glycoprotein involvement and itraconazole modulation Lifschitz, Adrian Luis; Ballent, Mariana; Virkel, Guillermo Leon; Sallovitz, Juan Manuel; Lanusse, Carlos Edmundo Ivermectin (IVM), a macrocyclic lactone used as antiparasite agent, has been reported as a P‐glycoprotein (P‐gp) substrate. The participation of P‐gp in the IVM excretion process has been previously demonstrated. Sex‐related differences in the kinetic behaviour of some macrocyclic lactone compounds have been observed. The aim of this work was to characterize in‐vivo the comparative gastrointestinal disposition of IVM in male and female rats. The sex‐related influence on the itraconazole (ITZ) modulation of P‐gp‐mediated IVM intestinal transport was also assessed. Sixty Wistar rats (30 male, 30 female) received IVM alone or co‐administered with ITZ. Rats were killed between 6 and 72h after treatment and blood, gastrointestinal tissues and lumen contents were collected. IVM concentrations were determined by high performance liquid chromatography. Substantial sex‐related differences in the IVM disposition kinetics were observed. Higher IVM systemic availability was observed in female rats. The ITZ‐mediated modulation of the IVM disposition kinetics had a differential impact between male and female rats. Co‐administration with ITZ resulted in a marked increase in the IVM concentrations in the wall tissue from different portions of the gastrointestinal tract of male rats. The presence of ITZ induced drastic sex‐related changes on the P‐gp‐mediated IVM gastrointestinal disposition.

Age and growth in Odontocymbiola magellanica (Gastropoda: Volutidae) from Golfo Nuevo, Patagonia, Argentina Bigatti, Gregorio; Penchaszadeh, Pablo Enrique; Cledón, Maximiliano Growth, age and somatic production of the benthic predator Odontocymbiola magellanica were studied in Golfo Nuevo (42S 65W), on the South American Atlantic shelf. Stable oxygen isotope ratios confirmed semiannual formation of internal and external shell growth marks. Mean shell length (SL) of females was 115 and 112 mm for males, while population modal shell-free wet mass (SFWM) was 62.8 g. A Gompertz growth function (SL¥ = 200 mm, K = 0.197, t0 = 5.486) fitted 113 pairs of size-at-age data (12 shells) best. O. magellanica is a long-lived species, reaching up to 20 years of age. The maximum individual somatic production of 29.3 g SFWM per year is attained at 145 mm SL, which corresponds to about 12 years of age. The life span of this volutid seems to be twice compared with other large gastropods. O. magellanica is a valuable and exploitable resource regarding its large size and somatic production, but on the other hand, its slow growth, late maturity and direct development makes it extremely vulnerable to overexploitation.Growth, age and somatic production of the benthic predator Odontocymbiola magellanica were studied in Golfo Nuevo (42S 65W), on the South American Atlantic shelf. Stable oxygen isotope ratios confirmed semiannual formation of internal and external shell growth marks. Mean shell length (SL) of females was 115 and 112 mm for males, while population modal shell-free wet mass (SFWM) was 62.8 g. A Gompertz growth function (SL¥ = 200 mm, K = 0.197, t0 = 5.486) fitted 113 pairs of size-at-age data (12 shells) best. O. magellanica is a long-lived species, reaching up to 20 years of age. The maximum individual somatic production of 29.3 g SFWM per year is attained at 145 mm SL, which corresponds to about 12 years of age. The life span of this volutid seems to be twice compared with other large gastropods. O. magellanica is a valuable and exploitable resource regarding its large size and somatic production, but on the other hand, its slow growth, late maturity and direct development makes it extremely vulnerable to overexploitation.

Kinetics of phosphate adsorption on goethite: Comparing batch adsorption and ATR-IR measurements Luengo, Carina Vanesa; Brigante, Maximiliano Eduardo; Antelo, Juan; Avena, Marcelo Javier The adsorption kinetics of phosphate on goethite has been studied by batch adsorption experiments and by in situ ATR-IR spectroscopy at different pH, initial phosphate concentrations and stirring rates. Batch adsorption results are very similar to those reported by several authors, and show a rather fast initial adsorption taking place in a few minutes followed by a slower process taking place in days or weeks. The adsorption kinetics could be also monitored by integrating the phosphate signals obtained in ATR-IR experiments, and a very good agreement between both techniques was found. At pH 4.5 two surface complexes, the bidentate nonprotonated (FeO)2PO2 and the bidentate protonated (FeO)2(OH)PO complexes, are formed at the surface. There are small changes in the relative concentrations of these species as the reaction proceeds, and they seem to evolve in time rather independently. At pH 7.5 and 9 the dominating surface species is (FeO)2PO2, which is accompanied by an extra unidentified species at low concentration. They also seem to evolve independently as the reaction proceeds. The results are consistent with a mechanism that involve a fast adsorption followed by a slow diffusion into pores, and are not consistent with surface precipitation of iron phosphate.

Non-interacting dimer kinetics in hypercubic lattices Costanza, Gregorio José; Manzi, Sergio Javier; Pereyra, Victor Daniel The exact formulation of the kinetic of dimer in hypercubic lattices is developed in the framework of the kinetic lattice gas model. The so-called local evolution rules are used to obtain the hierarchy of equation of motion for the correlation functions where processes like adsorption and desorption are included. The hierarchy of equations are truncated using a mean field (m, n) closures which allows the analytical treatment of the system. A general expression for non-interacting dimer isotherm and two particle correlation functions are obtained in hypercubic lattices.

Photoisomerization of Azobenzenes and Spirocompounds in Nematic and in Twisted Nematic Liquid Crystals Bossi, Mariano Luis; Murgida, Daniel Horacio; Aramendia, Pedro Francisco Samples of a nematic mixture of ZLI1132 and of a twisted nematic mixture composed of ZLI1132 and chiral inductor S811, including 1%-10% (w/w) 4-N,N-dimethylaminoazobenzene (DAB), (4′-nitro)-4-N,Ndimethylaminoazobenzene (NDAB), spiropyran (SP), or spirooxazine (SO) were irradiated to produce the photochromic transformation of the dopant. The changes in the system were monitored by time-resolved transmission spectroscopy, time-resolved birefringence, or polarized Raman scattering. The medium sensitivity of the kinetics and spectroscopy of some of the probes was used to derive information on polarity of the medium. In the systems studied, apart from the changes in absorption spectrum, great changes in birefringence can be photoinduced and the order of the nematic phase can be changed in either direction, depending on the dopant. The open form of SP can discriminate orientation polarity. Although the polarity parallel to the mesogenic director is similar to that for acetone, the perpendicular orientation has a polarity similar to acetonitrile. In agreement with this observation, the kinetics of the Z f E isomerization of NDAB, oriented parallel to the mesogenic director, also experiences a polarity similar to that for acetone. The decay rate constant of the open form of SP displays a linear relationship between its Arrhenius parameters, which is universal in a great variety of homogeneous solvents, solvent mixtures, and liquid crystals, therefore validating the hypothesis that the same type of transformation is observed in all these cases, namely, the decay of the open form monomer. The dopants used have been proven to be adequate probes of bulklike properties in locally heterogeneous systems as liquid crystals.

Sea quark polarization and semi-inclusive DIS data Jiang, X.; Navarro, Gabriela Alejandra; Sassot, Rodolfo We investigate the potential impact of forthcoming Jefferson Lab semi-inclusive polarized deep inelastic scattering proton measurements in the determination of the sea quark polarization in the nucleons by means of a next to leading order global QCD analysis. Specifically, we estimate the resulting improvement in the constraints on polarized parton densities for different flavors, which is found to be significant for up and strange quarks, and the correlation between remaining uncertainty ranges for each of the parton species.

Spin-charge separation and topological phase transitions in Aharonov-Bohm rings of interacting electrons Normand, B.; Hallberg, Karen Astrid; Aligia, Armando Ángel; Kampf, A. P. We investigate the properties of strongly correlated electronic models on a flux-threaded ring connected to semi-infinite free-electron leads. The interference pattern of such an Aharonov-Bohm ring shows sharp dips at certain flux values, determined by the filling, which are a consequence of spin-charge separation in a nanoscopic system. The conductance through such a molecule or nanodevice is related directly to its spectroscopic properties, opening new experimental possibilities for probing the phenomenology of strongly interacting systems. As a further example, for a ring described by the half-filled ionic Hubbard model we show that the weight of the first conductance peak as a function of gate voltage or external flux allows one to identify the topological charge transition between a correlated insulator and a band insulator.

High level expression of bioactive recombinant human growth hormone in the milk of a cloned transgenic cow Salamone, Daniel Felipe; Barañao, Jose Lino Salvador; Santos, Claudio; Bussmann, Leonardo Edmundo; Artuso, Jorge; Werning, Carlos; Prync, Aida; Carbonetto, Cesar; Dabsys, Susana; Munar, Carlos; Salaberry R; Berra, Guillermo; Berra, Ignacio; Fernández, Nahuel; Papouchado, Mariana; Foti, Marcelo; Judewicz, Norberto; Mujica, Ignacio; Muñoz, Luciana; Fernandez Alvarez, Silvina; González, Eliseo; Zimmermann, Juan; Criscuolo, Marcelo; Melo, Carlos Transgenic farm animals have been proposed as an alternative to current bioreactors for large scale production of biopharmaceuticals. However, the efficiency of both methods in the production of the same protein has not yet been established. Here we report the production of recombinant human growth hormone (hGH) in the milk of a cloned transgenic cow at levels of up to 5 g l(-1). The hormone is identical to that currently produced by expression in E. coli. In addition, the hematological and somatometric parameters of the cloned transgenic cow are within the normal range for the breed and it is fertile and capable of producing normal offspring. These results demonstrate that transgenic cattle can be used as a cost-effective alternative for the production of this hormone.

24-hour rhythms of splenic mitogenic responses, lymphocyte subset populations and interferon γ release after calorie restriction or social isolation of rats Cano, Pilar; Cardinali, Daniel Pedro; Fernández, Pilar; Reyes Toso, Carlos Felipe To assess the effect of calorie restriction equivalent to a 66% food restriction or social isolation on splenic immune responses, calorie-restricted five week-old male Wistar rats, pair fed controls individually caged and pair fed controls caged in groups, were studied for four weeks. Calorie restricted and isolated rats showed increased splenic concanavalin A response with peak activity during the activity span. Mean 24 h values of splenic lipopolysaccharide response decreased in isolated rats compared to grouped rats. The highest values of T cells occurred in calorie restricted rats and those of B cells in isolated rats. Mean values of splenic CD4+ and CD8+ cells augmented in isolated or calorie restricted groups. The highest in vitro interferon-gamma production occurred in the isolated group and the lowest in the grouped rats, the differences among groups being significant. Both experimental procedures generally disrupted 24-h rhythmicity of splenic immune parameters. Mean values of plasma corticosterone were higher in calorie restricted rats than in isolated rats and both differed significantly from grouped rats. The results indicate that either calorie restriction or social isolation augmented cell-mediated immunity in rat spleen.

PROPAT: A study to improve the quality and reduce the cost of diabetes care Gagliardino, Juan Jose; Olivera, E.; Etchegoyen, Graciela Susana; Guidi, Mabel Leticia; Caporale, J. E.; Martella, A.; De La Hera, M.; Siri, F.; Bonelli, P. Objective: In PROPAT we implemented an integrated approach to diabetes care designed to improve the quality and reduce the cost of care. Study design and methods: PROPAT was a case-control study matching patients by age and gender (diabetes:control ratio 1:2) within IOMA, a public employment-based health maintenance organization (HMO) of the Province of Buenos Aires, Argentina. Costs were evaluated using prevalence data from an HMO perspective. We currently report clinical and biochemical data and costs from the first 297 patients enrolled who completed 1 year in PROPAT, and compare them with those derived from control patients. Results: All recommended practices recorded as care provided at baseline increased significantly 1 year after implementing PROPAT, with a parallel significant improvement in several clinical and biochemical parameters, and markedly lower total annual per capita costs. Conclusions: These results demonstrate that the implementation of a comprehensive diabetes care program can simultaneously improve quality while reducing costs.

Preferencia alimentaria de arañas Misumenops pallidus (Araneae: Thomisidae) sobre potenciales insectos presa de cultivos de alfalfa; Feeding preferences of the spider Misumenops pallidus (Araneae: Thomisidae) on potential prey insects from alfalfa crops Cheli, German Horacio; Armendano, Andrea Viviana; Gonzalez, Alda Feeding preferences of the spider Misumenops pallidus (Araneae: Thomisidae) on potential prey insects from alfalfa crops. The spider Misumenops pallidus (Thomisidae) is commonly found in alfalfa crops. We studied its predatory preferences on potential insect prey, particularly regarding agroecosystems pests. Two kinds of tests were done under normal laboratory conditions: simultaneous presentation of prey (n= 215) and alternative prey test (n= 45). The spiders preferred insects that were mobile, small, without defensive glands and with thin exoskeletons. According to the amount of prey consumed, we established four predation levels: high (> 55%, on adult Drosophila melanogaster flies); intermediate (30% -55% on the defoliator larvae of Rachiplusia nu and adult heteropterans: Horciasinus argentinus and Halticus spegazzinii); and low (10%- 30% on the chrysomelids Colapsis sp. and Diabrotica speciosa). The pentatomid Piezodorus guildinii, the curculionid Naupactus sp. and the aphid Acyrthosiphom pisum were not accepted as food. Once the spider captured a prey item it did not accept another, independently of prey item species (82% of trials).

Antimicrobial activity of glycosidase inhibitory protein isolated from Cyphomandra betacea Sendt. fruit Ordóñez, Roxana Mabel; Ordóñez, Adriana; Sayago, Jorge Esteban; Nieva Moreno, María Inés; Isla, Maria Ines Broad-spectrum antimicrobial activity of an invertase inhibitory protein (IIP) isolated from Cyphomandra betacea ripe fruits is documented. Minimal inhibitory concentration (MIC) values were determined by agar macrodilution and broth microdilution assays. This IIP inhibited the growth of xylophagous and phytopatogenic fungi (Ganoderma applanatum, Schizophyllum commune, Lenzites elegans, Pycnoporus sanguineous, Penicillium notatum, Aspergillus niger, Phomopsis sojae and Fusarium mango) and phytopathogenic bacteria (Xanthomonas campestris pvar vesicatoria CECT 792, Pseudomonas solanacearum CECT 125, Pseudomonas corrugata CECT 124, Pseudomonas syringae pv. syringae and Erwinia carotovora var carotovora). The IIP concentration required to completely inhibit the growth of all studied fungi ranged from 7.8 to 62.5 μg/ml. Phytopatogenic bacteria were the most sensitive, with MIC values between 7.8 and 31.25 μg/ml. Antifungal and antibacterial activities can be associated with their ability to inhibit hydrolytic enzymes. Our results indicate the possible participation of IIP in the plant defense mechanism and its potential application as a biocontrol agent against phytopathogenic fungi and bacteria. © 2005 Elsevier Inc. All rights reserved.

A rare endemic land-snail from Argentina: Plagiodontes rocae Doering 1881 (Gastropoda: Orthalicidae: Odontostominae) Piza, Julia; Ghezzi, Natalia S; Cazzaniga, Néstor Jorge Plagiodontes rocae Doering 1881 is a strictly endemic species from the Paleozoic mountains of southern Buenos Aires province (Argentina). Its identity has been never controversial, but its description and discrimination from related species was still incomplete. A quantitative analysis of its measurements was advisable to locate the species in the frame of a morphological re-analysis of all species in genus Plagiodontes Doering1876. In this study, Protoconch sculpture is illustrated by SEM micrographs to rectify previous descriptions. Shell measurements and angles are studied by Multivariate Discriminant Analysis to discriminate it from other small-sized species. Genital anatomy of P. rocae is described for the first time, its quantitative data being discriminated by multivariate methods from those of the only co-existing Odontostominae, i.e., Plagiodontes pat-agonicus.; Plagiodontes rocae Doering 1881 ist eine endemische Art des paläozoischen Berglandes im Süden der Provinz Buenos Aires, Argentinien. Ihr Status als eigenständige Art ist nie in Frage gestellt worden, doch ist ihre Beschreibung und Differenzierung von nahestehenden Arten nicht abgeschlossen. Im Rahmen der Revision aller Plagiodontes-Arten, die wir derzeit durchführen, ist daher eine morphometrische Analyse angebracht, um die Art korrekt einzuordnen. Die Skulptur des Embryonalgehäuses wird mittels SEM-Mikrographie dargestellt. Gehäusemaße und -winkel werden mit Hilfe der Multivariaten Diskriminanzanalyse mit denen anderer kleingehäusiger Arten verglichen. Die Genitalanatomie von P. rocae wird hier zum ersten Mal beschrieben; ihre morphometrischen Daten werden mit Hilfe der Multivarianzanalyse mit P. patagonicus, des einzigen sympatrischen Vertreters der Odontostominae, verglichen.

Los cerraminetos verticales en tierra y su eficiencia economico-tecnologico-termico-energetica Garzon, Beatriz Silvia Se describe la adecuación bioambiental de las soluciones autóctonas de disposiciones tecnológicas de cerramientos verticales y las características económico-tecnológico-constructivas, consumo energético de producción, y la determinación de la eficiencia ecológica-térmico-energética de las alternativas planteadas(mampostería de adobe y paneles de madera, caña y barro), la verificación según normas de comportamiento térmico y su comparación con relación a los sistemas tecnológicos convencionales con los cuales se resuelven, en la mayoría de los casos, las viviendas de interés social, planteadas para estas comunidades desde otros sectores (oficial, privado, etc.).

Fully differential cross sections for C6+ single ionization of helium: The role of nucleus-nucleus interaction Ciappina, Marcelo Fabián; Cravero, Walter Ruben In this work, we present fully differential cross section (FDCS) calculations using distorted wave theories for helium single ionization by 2 MeV amu-1 C6+ ions. We study the influence of internuclear interaction on low-energy electron emission in the scattering plane. It is shown that by incorporating an internuclear effective charge which depends on the collision momentum transfer and taking into account its interplay with passive electron screening we obtain better agreement with experiments in most cases under consideration. Comparisons are made with absolute experimental measurements and with other theories. We found that for ejected-electron momentum similar to transferred momentum, internuclear potential effects have little contribution to FDCSs.

Bacterioterapia con lactobacilos probióticos para la prevención de infecciones urogenitales Nader, Maria Elena Fatima Los lactobacilos son los microorganismos predominantes en el tracto gastrointestinal y urogenital del hombre y los animales homeotermos. También se emplean en la elaboración de diferentes alimentos, lo que los categoriza como GRAS (generally regarded as safe). Si bien están disponibles en productos vaginales en el mercado farmacéutico, hay escasas evidencias de su efectividad para la prevención de infecciones urogenitales. Nuestro grupo de trabajo ha aislado lactobacilos vaginales humanos, seleccionando aquellos con propiedades benéficas o probióticas. Se han estudiado las características tecnológicas para obtener el mayor número de microorganismos vivos (biomasa) y las condiciones para la producción óptima de sustancias antagónicas frente a patógenos urogenitales (ácidos orgánicos, peróxido de hidrógeno, bacteriocinas). Se ha demostrado en animales de experimentación (ratones BALB/c hembra endocriados) que la administración intrauretral de lactobacilos no produce efectos adversos ni modificaciones estructurales o ultraestructurales, previniendo eficazmente las infecciones urinarias. Es necesaria la complementación de estos resultados con estudios en pacientes para demostrar la efectividad de la administración intravaginal de los lactobacilos probióticos seleccionados en la recolonización de la microbiota urogenital, la prevención o la terapia de los diferentes síndromes y cuadros clínicos que afectan al tracto, su efecto sobre las embarazadas, etc., que permitan proponer la bacterioterapia con lactobacilos como alternativa válida a la terapia con otras drogas.; Lactobacilli are the predominant microorganisms in the gastrointestinal and urogenital tracts of human beings and homeotermic animals. They are also used for the elaboration of different fermented foods being categorized as GRAS (generally regarded as safe). Even though they are included into different vaginal products in the pharmaceutical market, there are small amount of evidences of their effectivity in the prevention of urogenital infections. Our research group have isolated human vaginal lactobacilli, selecting those with beneficial or probiotic properties. The technological characteristics to obtain the higher number of viable (biomass) microorganisms and the conditions for the optimal production of antagonistic substances against pathogenic microorganisms (organic acid, hydrogen peroxide, bacteriocins) were determined. In experimental animals (inbreed female BALB/c mice) we demonstrated that the intraurethral administration of lactobacilli does not produce adverse effects or structural or ultra structural modifications in the urogenital tract, preventing effectively the urinary tract infections. The complementation of these results with human assays is necessary to demonstrate effectively the intravaginal administration of selected probiotic lactobacilli on the recolonization of the urogenital microbiota, the prevention or therapy of different clinical syndromes, their effect on pregnant women, etc, that will allow the proposal of the bacteriotherapy with lactobacilli as a valid alternative to the other drugs therapies.

Compensatory renal growth protects mice against Shiga toxin 2-induced toxicity Camerano, Gabriela Veronica; Bustuoabad, Oscar David; Meiss, Roberto Pablo; Gómez, Sonia Alejandra; Fernández, Gabriela Cristina; Isturiz, Martín Amadeo; Palermo, Marina Sandra; Dran, Graciela Isabel Uninephrectomy (Unx) is followed by the compensatory renal growth (CRG) of the remaining kidney. Previous evidence has shown that during CRG, renal tissue is resistant to a variety of pathologies. We tested the hypothesis that the functional changes that take place during CRG could attenuate Shiga toxin (Stx) toxicity in a mouse model of Stx2-induced hemolytic uremic syndrome (HUS). The participation of nitric oxide (NO) was analyzed. After CRG induction with Unx, mice were exposed to a lethal dose of Stx2, and the degree of renal damage and mortality was measured. Stx2 effects on the growth, renal blood flow (RBF) and NO synthase (NOS) intrarenal expression in the remaining kidney were then studied. The induction of CRG strongly prevented Stx2-mediated mortality and renal damage. Administration of the NOS inhibitor NG-nitro-L-arginine methyl ester (L-NAME) during CRG partially impaired the protection. Both Stx2 and L-NAME interfered with the hypertrophic and hyperplastic responses to Unx, as well as with the increase in RBF. In intact mice, Stx2 decreased renal perfusion, inhibited endothelial NOS basal expression and enhanced inducible NOS expression; all of these effects were attenuated by prior Unx. It is concluded that during CRG mice are highly protected against Stx2 toxicity and lethality. The protective capacity of CRG could be related to the enhancement of renal perfusion and preservation of eNOS renal expression, counterbalancing two major pathogenic mechanisms of Stx2.

Response to Comment on "Cathepsin-L Influences the Expression of Extracellular Matrix in Lymphoid Organs and Plays a Role in the Regulation of Thymic Output and of Peripheral T Cell Number" Lombardi, Gabriela; Burzyn, Dalia; Mundiñano, Juliana; Berguer, Paula Mercedes; Costa, Hector Luis; Goldman, Alejandra; Piazzon, Margarita Isabel; Nepomnaschy, Irene In our article published in The Journal of Immunology in June 1, 2005 (1), we reported that lymph nodes from nackt mice (CTSLnkt/CTSLnkt) are hypertrophied, showing a normal absolute number of CD4+ T cells and a marked increase in the number of CD8+ T lymphocytes. Correlatively, extracellular matrix (ECM) components were found to be increased. Contrarily, in nackt thymus, laminin, fibronectin, and collagen I and IV are markedly decreased, with an augmented output of CD8+ cells. We also reported that a mutated form of cathepsin L can be detected in different organs in nackt mice. These results demonstrate that the nackt mutation in the Ctsl gene influences the levels of ECM components in lymphoid organs, the thymic output, and the number of T cells in the periphery, thus broadly affecting the immune system.

Environmental control of phenological development in two Lesquerella species Windauer, Liliana; Slafer, Gustavo Ariel; Ravetta, Damián Andrés; Benech-Arnold, Roberto Luis Lesquerella fendleri and Lesquerella mendocina are two species with potential for domestication as crops for semiarid regions. Understanding the environmental influences on development is a critical step for the introduction of a wild species into cultivation. Under controlled conditions these species responded differently to temperature: L. fendleri phenological approach toward flowering responded linearly to temperature, whereas initiation of flowering in L. mendocina was relatively insensitive to temperature. L. fendleri exhibited a quantitative response to supra-optimal temperatures (with rate of development reduced with further increases in temperature) whereas L. mendocina showed a qualitative response, no flower development at supra-optimal temperatures. In this work undertaken in the field we studied phenological development in L. fendleri and L. mendocina as a function of planting date, quantified the time required to reach particular phenological stages under the various thermal environments, and compared these results with those previously obtained with controlled conditions. We also studied the influence of photoperiod on plant phenology in field situations and through experiments done under controlled conditions. Development rate for both species varied with sowing date with plant cycles shorter in spring sown plants, even if measured in thermal time. L. mendocina plants sown in late spring displayed a biennial cycle. These results are consistent with those obtained under controlled conditions. However, cycle shortening in thermal time with delays in sowing date suggested that factors other than temperature also influenced phenology of these two species. Further studies under controlled conditions showed that phenological development of L. fendleri plants was also altered by photoperiod, with plants displaying a typical long-day response. At the highest temperatures used in these studies L. mendocina plants did not respond to photoperiod. The possibility that incident radiation is involved in L. mendocina response to sowing date is discussed.