Air drying technique for cytogenetic studies in freshwater planarians (Platyhelminthes)

Fil: Margaría, Cecilia Beatriz. Facultad de Ciencias Naturales y Museo; Universidad Nacional de La PlataFil: Dulout, F.N.. Ctro. Invest. Genet. Basica y Apl.; Facultad de Ciencias Veterinarias; Universidad Nacional de La Plat

Searching for the symbolic dimensions of la tunita, Sierra de Ancasti, Catamarca, Argentina

En este trabajo analizamos las dimensiones materiales, simbólicas y subjetivas de un particular espacio emplazado en la Sierra de Ancasti (provincia de Catamarca, noroeste argentino) conocido como La Tunita. Alegamos que singulares atributos naturales y espaciales favorecieron su incorporación a la dinámica social durante el Período de Integración Regional (ca. s. III d.C. hasta el s. XI o XII). La Tunita se distingue por un importante conjunto de manifestaciones rupestres que visibilizan la cosmovisión Aguada en una vía de transito que articula la Sierra de Ancasti con el oeste catamarqueño. Este lugar habría jugado un importante rol al incidir de manera significativa en el plano simbólico-ideológico, permitiendo ordenar el entorno natural y transformarlo en un espacio social de gran significación en el contexto macroregional. No obstante el predominio de la impronta Aguada, la evidencia sugiere que otros grupos sociales en su devenir histórico pudieron haber operado desde una lógica similar. Asumimos que algunas imágenes de La Tunita guardan relación con los conflictos y tensiones sociales que parecen haber ocurrido en tiempos de Aguada. Así planteamos que las imágenes y ciertos rituales se constituyeron en aliados importantes en el ejercicio del control y el poder tanto al interior de la sociedad como para reafirmarse ante otros grupos, en momentos donde la interacción social en un amplio territorio debió requerir la adopción de prácticas tendientes a reforzar aspectos ideológicos en determinados lugares.In this paper we will analyse the material, symbolic, and subjective dimensions of a very particular space geographically located in Sierra de Ancasti (Province of Catamarca, in the north western of Argentina) known as La Tunita. We argue that several and unique natural and spatial attributes in La Tunita favoured its incorporation to the social dynamic during the Regional Period of Integration (ca. s. III D.C. – s. XI / XII). La Tunita distinguished itself for the existence of an important array of rock art manifestations which in turn materialize the Aguada culture cosmovision. This place would have played an important role in infl uencing significantly at a symbolic-ideological level, allowing arranging the natural environment and transforming it into a social space of great signifi cance in the macro regional context. Despite of the prevalence of Aguada imprint, evidence suggests that other social groups in the course of history could have operated from a similar logic. We assume that some pictures of La Tunita are related to the confl icts and social tensions that seem to have occurred in times of Aguada. In this way, we pose that the images and some rituals have become important allies in the exercise of control and power within society to assert against other groups when social interaction in a vast territory should have required the adoption of practices which reinforce some ideological aspects in certain places.Fil: Nazar, Carlos Domingo. Universidad Nacional de Catamarca. Escuela de Arqueología; ArgentinaFil: de la Fuente, Guillermo Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Catamarca. Escuela de Arqueología; ArgentinaFil: Dulout, Luis Noel. Universidad Nacional de Catamarca; Argentin

Sylviculture et nutrition des accrus de frêne dans les Hautes-Pyrénées

Le projet CHAPAY a contribué à produire des connaissances, des méthodes et des outils pour prendre en compte les relations entre le changement des activités agricoles et des paysages dans l’action publique et la gouvernance des territoires. Le frêne trouve dans de nombreux sites des Hautes-Pyrénées des conditions favorables à son installation, mais sa croissance est très variable selon les stations. L’exploitation forestière de ces accrus nécessite, au préalable, une connaissance du potentiel de croissance auquel on peut s’attendre selon la fertilité de la station concernée. Nos résultats sont fondés sur une étude de terrain portant sur des accrus représentatifs des Hautes-Pyrénées. Nous les avons classés en niveaux de potentiel de croissance actuels et futurs et nous avons interprété ces niveaux par rapport aux données de fertilité chimique des stations. Cette méthodologie peut être étendue à d’autres régions et à d’autres types d’accrus. Elle peut servir de base à une catégorisation des accrus selon leur intérêt écologique ou économique

Management of inflorescence and viable seed production of blackgrass (Alopecurus myosuroides) on set-aside in France

International audienceTwo experiments were carried out, one in a glasshouse and the other in the field, to assess the effect of weeding management (type and date) on blackgrass seed production during set-aside. The results of the field experiment were used to establish relationships between head length and spikelet number per head. Head number per plant was not reduced by one mowing in glasshouse, but it was reduced by double mowing. Early (beginning of anthesis) or intermediate (half-anthesis) glyphosate reduced head number by 72 or 50%, respectively, compared to a control, but later (during seed ripening) application did not. A first mowing reduced the length of heads elongated after the mowing by 25% compared to a control, but less than two successive mowings (by 50%). Seed viability was greatly reduced by early glyphosate (by 91%) compared to a control, less by medium date spraying and two mowings (by 17 and 47%, respectively), and not by one mowing or late spraying. These results were checked at two densities in the field experiment. The results of head length for low density were consistent with those in glasshouse, but head number did not differ between treatments. Head number per plant and head length at the highest density were lower (from 50 to 76% according to the treatments for head number and from 3 to 16% according to the treatments for head length) than those for individual plants. These preliminary results give indications, which should be checked in farmers’ field conditions, for better control of blackgrass in set-aside fields

Butylated hydroxytoluene does not protect Chinese hamster ovary cells from chromosomal damage induced by high-dose rate 192Ir irradiation

Previous reports showed the protective effect of the synthetic antioxidant butylated hydroxytoluene (BHT) against the chromosomal damage induced by bleomycin (BLM), cadmium chloride and potassium dichromate. To test the hypothesis that this effect was exerted by inhibition and/or scavenging of reactive oxygen species (ROS), the effect of BHT on the chromosomal damage induced by a high dose-rate gamma rays (HDR 192Ir). Experiments were carried out by irradiating G1 CHO cells with nominal doses of 1, 2 or 3 Gy. BHT (doses of 1.0, 2.5 or 5.0 μg/ml) was added to the culture immediately before or immediately after irradiation. Cells were then incubated in the presence of BHT for 13 h until harvesting and fixation. Results obtained showed that BHT did not decrease the chromosomal damage induced by radiation in any consistent fashion. On the contrary, in cells post-treated with 5.0 μg/ml of BHT the yield of chromosomal aberrations increased in several experimental points. These results with ionizing radiation suggest that the previous observed protective effects of BHT on the chromosomal damage induced by chemical genotoxicants may not be mediated solely through the scavenging or inactivating reactive oxidative species. The decrease of the yield of chromosomal damage induced by BLM could be due to the union of BHT with a metallic ion, in this case Fe (II), required for the activation of BLM. In the same way, the protective effect of BHT on the chromosomal damage induced by cadmium chloride and potassium dichromate could be due to the decrease of the effective dose of both salts in the cell through the chelation of the cations by BHT.Instituto de Genética VeterinariaFacultad de Ciencias Veterinaria

Butylated hydroxytoluene does not protect Chinese hamster ovary cells from chromosomal damage induced by high-dose rate 192Ir irradiation

Previous reports showed the protective effect of the synthetic antioxidant butylated hydroxytoluene (BHT) against the chromosomal damage induced by bleomycin (BLM), cadmium chloride and potassium dichromate. To test the hypothesis that this effect was exerted by inhibition and/or scavenging of reactive oxygen species (ROS), the effect of BHT on the chromosomal damage induced by a high dose-rate gamma rays (HDR 192Ir). Experiments were carried out by irradiating G1 CHO cells with nominal doses of 1, 2 or 3 Gy. BHT (doses of 1.0, 2.5 or 5.0 μg/ml) was added to the culture immediately before or immediately after irradiation. Cells were then incubated in the presence of BHT for 13 h until harvesting and fixation. Results obtained showed that BHT did not decrease the chromosomal damage induced by radiation in any consistent fashion. On the contrary, in cells post-treated with 5.0 μg/ml of BHT the yield of chromosomal aberrations increased in several experimental points. These results with ionizing radiation suggest that the previous observed protective effects of BHT on the chromosomal damage induced by chemical genotoxicants may not be mediated solely through the scavenging or inactivating reactive oxidative species. The decrease of the yield of chromosomal damage induced by BLM could be due to the union of BHT with a metallic ion, in this case Fe (II), required for the activation of BLM. In the same way, the protective effect of BHT on the chromosomal damage induced by cadmium chloride and potassium dichromate could be due to the decrease of the effective dose of both salts in the cell through the chelation of the cations by BHT.Instituto de Genética VeterinariaFacultad de Ciencias Veterinaria

Use of the anaphase-telophase test to detect aneugenic compounds : Effects of propionaldehyde and cadmium chloride

Aneuploidy is a numerical chromosomal disorder originated from nondisjunction during cell division (Dellarco 1985). Aneuploid cells exhibit altered chromosome numbers varying from nulisomy (absence of a chromosome pair), monosomy (only one member of a chromosome pair), trisomy (three homologous chromosomes instead of two), tetrasomy (four homologous chromosomes instead of two), etc. In an aneuploid complement, one or more chromosome pairs can be involved. In human beings aneuploidy is the main cause of pregnant loss, congenital malformation and mental retard (Hook 1983; Epstein 1988). Although the consequences of meiotic non-disjunction are clear, the relation between mitotic non-disjunction and neoplastic transformation susbsists uncertain despite there is increased evidence indicating that it is a significant factor during somatic malignancy development (Kondo 1984; Tsutsui 1983; Cavenee 1983). In addition, aneuploidy is frequently associated with infertility and abortion in domestic livestock (Halnan 1989). (Párrafo extraído del texto a modo de resumen)Instituto de Genética Veterinari

Mitochondrial variability in the D-loop of four equine breeds shown by PCR-SSCP analysis

A fragment of 466 base pairs from a highly variable peripheral region of the mitochondrial D-loop of horses was amplified and analyzed by single stranded conformational polymorphism (SSCP). Fourteen distinct SSCP variants were detected in 100 horses belonging to four breeds (Arabian, ARB; Thoroughbred, TB; Argentinian Creole, ARC; and Peruvian Paso from Argentina, PPA). Each breed showed four to eight SSCP variants, many of which were shared between two or three of the studied breeds. Arabian horses were the most variable (eight variants), with three variants unique to the breed. PPA and ARC showed two and one characteristic SSCP variants, respectively, while TB shared all its variants with at least one of the other breeds. An analysis based on the presence/absence of the variants revealed a closer relationship between PPA and TB, which was not completely unexpected considering the mixed ancestry of the PPA mares. The results also confirm the efficiency of SSCP to detect variability in horse mitochondrial DNA.Instituto de Genética Veterinari

Mechanisms involved in the induction of aneuploidy: The significance of chromosome loss

The induction of aneuploidy by physical and chemical agents using different test systems was evaluated. The effect of X-rays, caffeine, acetaldehyde, ethanol, diethylstilbestrol, propionaldehyde, and chloral hydrate was studied by chromosome counting in Chinese hamster embryonic diploid cells. Aneugenic ability of cadmium chloride, cadmium sulfate, potassium dichromate, chromium chloride, nickel chloride, and nickel sulfate was assessed by means of anaphase-telophase analysis in Chinese hamster ovary cells. Chromosome counting in human fibroblasts (MRC-5 cell line) was employed to evaluate the effect of cacodilic acid, cadmium chloride, cadmium sulfate, and potassium dichromate. Finally, the induction of kinetochore-positive and kinetochore negative micronuclei by cadmium chloride, cadmium sulfate, potassium dichromate, chromium chloride, and nickel chloride was studied using CREST antibodies. When the effect of different agents was determined by chromosome counting, an increase of hypoploid but not of hyperploid cells was observed. Anaphase-telophase analysis showed that metal salts increased the frequency of lagging chromosomes. This finding has been confirmed by the increment of kinetochore-positive micronuclei using CREST antibodies. Therefore, chromosome loss could be considered as the main cause of induced aneuploidy.Facultad de Ciencias VeterinariasInstituto de Genética Veterinari