Étude polarographique de la mobilisation du fer de la ferritine

Polarographic study of the mobilization of ferritin ironPolarographic study allows to propose a model for mobilization of ferritin iron: an equilibrium exists between iron core and small quantities of iron outside the protein.These iron atoms would be lying on electron acceptor sites including SH groups. The number of sites is dependent on iron content of ferritin.Therefore, the iron could be removed by the action of reducing agents such as xanthine oxidase or ascorbic acid, and then chelated by a complexing agent.     

Etude préliminaire des effets de la mise en eau du Réservoir de LG-2 (Territoire de la Baie James,Québec) sur le seston grossier et le zooplancton des rivières et des lacs inondés

Preliminary Study of the Effects of Impoundment of LG-2 Reservoir (James Bay Territory, Quebec) on the Net Seston and the Zooplankton of Impounded Rivers and Lakes The effects of impoundment on the biomass of net seston and zooplankton in lakes and rivers of Northern Quebec were investigated from 1978 to 1980, before, during and after the completion of LG2 Reservoir on the River La Grande (53° 54′ N, 76° 78′ W). In lotic stations, a 41–77% decrease in net seston was observed due to sedimentation of mineral particles (36–80 mg/m³ in 1978 to 10–21 mg/m³ in 1979). The ratio of organic to total seston increased from an average of 0.18 before the impoundment to 0.65 after. The flooding phase brought about a trophic upsurge; the biomass of the zooplankton increased by one to two orders of magnitude at the various sites; the greatest increases occurred in the central stations near the dam, the smallest in the upper stations near the inflow. In lake stations, no significant difference between years could be detected; the mean zooplankton biomass for all three years ranged from 6.59 mg/m³ to 34.34 mg/m³. Spatial variations between lakes were however significant. Results are compared with those in other natural lakes in Canada and reservoirs in the United States. Comparative examination of phytoplankton biomass before and after impoundment of LG2 Reservoir suggests that bacterioplankton and allochthonous organic material are key elements in the pelagic food chain after impoundment.     

Étude thermodynamique de la transition hélice–pelote statistique en solvants mixtes de différents esters de l'acide poly(L-glutamique)

Helix–coil transition of poly(γ-methyl-L -glutamate), poly(γ-ethyl-L -glutamate), and poly(γ-benzyl-L -glutamate) has been studied in mixed solvents by calorimetry, polarimetry, and viscometry. The experimental data have allowed the evaluation of solvation enthalpy Δh_b, equilibrium constant K for hydrogen bond formation between the active solvent component and CO and NH groups, and the cooperativity parameter σ. The conformational transition of polypeptides in solution in a mixed solvent containing enough active solvent to maintain the coiled conformation has been produced by dilution with the helix-supporting solvent for the measurements of enthalpy of transition Δh_s. The average value for Δh_s is 3550 ± 300 J/mol and is practically independent of the nature of the side chain for the dichloroacetic acid-ethylene dichloride solvent pair at 25°C. A noticeable concentration effect exists in the case of poly(γ-benzyl-L -glutamate). The helical conformation is less stable for poly(γ-ethyl-L -glutamate), and this is explained by a steric effect hindering the access of dichloroacetic acid to side chains. Constant K has been calculated using polarimetric data and also from values of Δh_s obtained at different temperatures using the Bixon and Lifson theory on the one hand and that of Sayama and coworkers on the other hand. Values of σ for poly(γ-ethyl-L -glutamate) have been calculated according to both theories mentioned, and the results show that the two sets of values are quite similar. The constant σ depends on the nature of the active solvent, on temperature, and on the binary-solvent composition. These conclusions are confirmed by viscometric results. Values of Δh_b calculated from constant K are 5230 J/mol when Bixon and Lifson theory is used and 5569 J/mol when the theory at Sayama and coworkers is used. In both cases the value for Δh_b is much lower than that of an intramolecular hydrogen bond. Experimental results suggest that the solvation mechanism would proceed in a manner so that mechanisms described in both theories are involved.     

Densidad Poblacional y Disponibilidad de Híbitat de la Danta de Montaña (Tapirus pinchaque) en los Andes Centrales de Colombia1

Population density of Tapirus pinchaque was estimated in 7000 ha Parque Nacional Natural Los Nevados in the central Andes of Colombia. Eight variables were measured in 110 left rear foot prints of the mountain tapir: total length and width, and length and width of the three toes. This information was analyzed with Cluster Analysis by means of UPGMA and Euclidean distance using the scores obtained by means of a Principal Component Analysis (PCA) using the eight variables. Habitat availability was measured in 147,000 ha using aerial photographs taken during the 1950s and 1980s. The results of the cluster analysis showed that there are between 11 and 15 individuals, for a mean density of one individual for each 551 ± 85 ha. The measurements of forest cover in the 147000 ha showed that habitat availability for the mountain tapir (montane forests and forestry plantations) increased 18l4lha from the 1950s to the 1980s. This increment in forest cover seems to have a positive effect on the local population size of T. pinchaque, since in areas previously covered by pastures, there are now secondary forests where tapirs tracks and feces can be found.     

Factores asociados con la presencia de endoparásitos y ectoparásitos en perros domiciliados de la zona metropolitana de Toluca,México

Introduction:

Endoparasites and ectoparasites in dogs are of global distribution. The close relationship between dogs and man implies a risk for the transmission of zoonotic parasites. Therefore, it is necessary to determine the parasites hosted by dogs in specific areas and the factors associated with their presence.

Objectives:

To identify and to estimate the prevalence of endoparasites and ectoparasites in domiciled dogs in the Metropolitan area of Toluca, México, and the prevalence of D. caninum in fleas of the genus Ctenocephalides spp.

Materials and methods:

We collected samples from 402 domiciled dogs in four reference hospitals in the area in Toluca. We diagnosed endoparasites using direct smear, flotation, and sedimentation techniques and we performed the taxonomic identification of ectoparasites. Finally, the molecular diagnosis of D. caninum in fleas was made using the polymerase chain reaction technique (PCR).

Results:

A total of 37.2% of dogs were positive for endoparasites; the genera or species identified were Toxocara spp., Giardia spp., Ancylostoma spp., Cystoisospora spp., D. caninum, Taenia spp., and Trichuris vulpis; the prevalence of ectoparasites was 13.13%. We identified fleas of the species Ctenocephalides felis, Ctenocephalides canis; only one animal was parasitized with Rhipicephalus sanguineus and another one with Trichodectes canis; the prevalence of D. caninum in fleas was 9.5%.

Conclusion:

The prevalence of endoparasites was 37.2% while that of ectoparasites was 13.1%; this is the first analysis of endoparasites and ectoparasites conducted in the same population of dogs in México together with the molecular diagnosis of D. caninum in fleas.     

Contribution à l'étude de la structure de la chromatine: I - Etude physico-chimique de la stabilité de la chromatine

Physicochemical studies of calf thymus chromatin were performed on micromicellar suspensions by thermal denaturation. These diluted suspensions were obtained, by a controlled shearing method, from a compact gel chromatin. Sedimentation and free-flow electrophoresis determined the size distribution of these particles. The most important result is a new transition on the melting profiles corresponding to a sudden increase of solution turbidity. This chromatin solution transition occurs at a higher temperature than usual DNA transition. The degree of « turbidity transitiondiminishes with micelle size but disappears when they are very mildly degraded by DNAases and when F₁ histone fraction is removed.This transition is not only size dependent but also depends on the micellar structure. This phenomenon is interpreted as an excluded volume effect by contact between compact and native regions of nucleoprotein micelles and denatured coils of DNA. Our study tried to show that the degree of turbidity transition can be a criterion of chromatin native structure.     

An electron microscopic study of the relation between length and transforming activity of H. influenzae DNA

Summary Transforming DNA of H. influenzae is broken down by sonication.The change of transforming activity is related to the change of length distribution.The length distribution is measured by electron microscopy using the spreading technique on a protein monolayer.An attempt to fractionate DNA samples by sucrose gradient sedimentation indicates that no monodisperse fractions can be obtained.An experimental relation between length of DNA and transforming activity is established.     

Interaction entre la cochenille du manioc Phenacoccus manihoti et ses différentes plantes-hôtes: étude de la teneur de la sève en acide aminé et en sucre

Résumé L'analyse (acides aminés et sucres) d'extrait de feuille, de 5 variétés de manioc (Manihot esculenta), du Faux caoutchouc (Hybride deM. esculenta x M.glaziovii), du Poinsettia (Euphorbia pulcherrina) et du Talinum (Talinum triangularae), caractérisés par différents degrés de résistance par antibiose à la cochenille du manioc (Phenacoccus manihoti (Mat. Ferr.)) (Homoptera: Pseudococcidae), a été réalisée sur des extraits obtenus par centrifugation du matériel foliaire. Les teneurs en acids aminés, très différentes d'une plante à l'autre, apparaissent aussi importantes entre les variétés de l'espèce manioc qu'entre les différentes espèces végétales avec respectivement un rapport de variation de 4,5 et 5,5. De même, les teneurs en sucres (exprimées en équivalent saccharose), sont très différentes d'une plante à l'autre avec un rapport de variation de 1 à 33 entre les deux extrêmes, si l'on ne considère que l'espèceM. esculenta, il n'est plus que de 3,5.Des différences dans les proportions relatives des acids aminés libres d'extrait de feuille sont observées aussi bien entre les variétés de manioc qu'entre les espèces végétales. Cependant pour toutes les plantes étudiées l'acide glutamique, la glutamine, l'ethanolamine, et l'alanine représentent près de 50% des acides aminés de l'extrait de feuille; l'acide aspertique, l'asparagine et la sérine près de 20% tandis que la tyrosine, la méthionine, l'isoleucine, la leucine et la lysine sont présents en très faibles pourcentages.Le degré de résistance à la cochenille du manioc des différentes plantes-hôtes n'a pu être relié, ni à la teneur de leur extrait de feuille en acides aminés et en sucres, ni à leur composition relative en acides aminés. Il n'a pu être non plus relié au rapport Sucres/Acides aminés Nos résultats suggèrent que des caractéristiques biochimiques autres que celles étudiées dans ce travail interviennent dans les mécanismes de résistance vis-à-vis de la cochenille du manioc.

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Summary The levels of sugars and amino acids were determined in leaf extracts from a number of plants showing different levels of resistance to the cassava mealybug,Phenacoccus manihoti (Homoptera: Pseudococcidae). There were five varieties of cassava (Manihot esculenta), as well as a hybrid obtained by crossingM. esculenta andM. glaziovii, poinsettia (Euphorbia pulcherrina) and talinum (Talinum triangularae). The variability in the total concentration of amino acid concentrations was as great between varieties of cassava as at the species level. In contrast, there was much less variability in the concentration of sugars at the intervarietal that at the interspecies level.While there were both intervarietal and interspecific differences in the amino acid composition, glutamic acid, glutamine, ethanolamine and alanine represented nearly 50% of the total in all plants examined. Aspartic acid, asparagine and serine accounted for approximately 20%, while tyrosine, methionine, isoleucine, leucine and lysine are present at low levels.The different levels of resistance noted in the different plants were not associated with the concentrations of either amino acids or sugars, the ratios of sugar/amino concentrations or the amino acid compositions obtained from leaf extracts. This suggests that other aspects of plant chemistry confer resistance to cassava mealybugs.

     

Efectos del Modelo de Atención Centrado en la Persona en la calidad de vida de personas con deterioro cognitivo de centros gerontológicos

Introduction

The Model of Person Centered Care has attracted increasing interest for use in gerontology centers. Therefore, the contributions about its impact are scarce in our context. The objective of this paper is to establish the impact that the interventions associated with the Model of Person Centered Care in the «Etxean Ondo» Project have on the quality of life of residents with cognitive impairment.

Material and methods

One hundred and ninetten residents with cognitive impairment were selected: 59 in the control group and 60 in the experimental group. Subjects in each group were sorted by cognitive impairment: mild or severe. Changes were implemented in the physical and organizational environments for the promotion of autonomy and wellbeing. Quality of life was assessed before and 6 months after intervention using the Fumat Scales (mild cognitive impairment) and Qualid (severe cognitive impairment). The t-Student test was used for comparison of means.

Results

In intergroup comparisons, significant differences in the Fumat Scale for the control group with mild cognitive impairment were initially identified. These differences were not recorded in the post assessment. The experimental group with severe cognitive impairment was significantly improved in the Qualid Scale post assessment. In intragroup comparisons, significant improvements were evident in the quality of life of experimental subjects, both with severe cognitive impairment (Qualid) and mild (Fumat).

Conclusions

The findings support the effectiveness of the interventions and identify methodological and conceptual issues that have been considered to analyze the Model of Person Centered Care efects.     

La diversité floristique de la végétation psammophile de la région de Tlemcen (nord–ouest Algérie)

This study is devoted to the analysis of the psammophyte of the coastal and semi-continental dunes in Tlemcen. Interesting results have been obtained, in particular, on the biological and ecological aspects of the psammophyte. The interpretation from Factoriel analysis of correspondences enabled us to identify the different phytosociological classes (Cakiletea maritimae, Ammophiletea, Quercetea ilicis, Therobrachypodietea and Stellarietea mediae). Some of these classes (Cakiletea maritimae and Ammophiletea) inhabit, exceedingly well, the embryonic dunes. Some species (Therobrachypodietea) colonize the quickset dunes. Lastly, some others (Quercetea ilicis) settle in the more mature and stable dunes. By using the phytosociological and phytodynamical data, we have been able to understand the vegetation and its diversity. To cite this article: H. Stambouli-Meziane et al., C. R. Biologies 332 (2009).     

Caracterización de la micobiota aérea en dos depósitos del Archivo Nacional de la República de Cuba

BackgroundThe high relative humidity and temperatures in tropical countries create favorable conditions for development of fungi that are not only a risk to human health but they can also colonize documentary support.AimsTo study the concentration of the airborne fungi in two repositories of the National Archives of the Republic of Cuba, the mycobiota deposited on different photographic supports and maps preserved in these repositories, and to determine the taxonomic characterization of the fungi isolated.MethodsThe air sampling was performed using a sedimentation method, and the supports (6 pictures and 7 maps) were analyzed using moistened sterile swabs.ResultsThe Cladosporium genus was predominant, followed by Aspergillus and Penicillium genera. Filamentous fungi were isolated in all the photos and maps, and yeasts were only isolated from a photographic supports and a map. We identified several species of Aspergillus and Penicillium genera, but Aspergillus niger and Aspergillus flavus predominated. Candida and Rhodotorula were the yeast genera isolated.ConclusionsThe fungal concentration of the air demonstrated that the environments were not contaminated. From the 26 species of filamentous fungi isolated only 5 were detected in the indoor air of the repositories and on one or more of the document supports analyzed (representing a 19.3%). This shows that there is a low ecological relationship between the fungi detected in the indoor air and those that were isolated from the supports studied.     

Membrana de cáscara de huevo para la curación de heridas superficiales en ratones

Introduction:

Eggshell membranes offer beneficial properties for tissue regeneration and their biomedical applications are important.

Objective:

To demonstrate the effectiveness of hen unfertilized eggshell membranes in the treatment of superficial open wounds in mice compared to the conventional procedure.

Materials and methods:

15-mm linear wounds were made on the back of 10 male CF-1 mice. The mice were divided into four groups. One group did not receive any treatment and the other three were given conventional treatment, eggshell membranes dressing, and eggshell membranes powder. The evolution of the wounds was registered by photographs.We measured wounds length and healing time and calculated the length reduction rate and the percentage of healing. The healing percentages were analyzed by ANOVA with a post hoc Dunnett test (p<0.05).

Results:

The treatments with eggshell membranes and membrane powder had a wound- length reduction rate of 1.009 and 1.020 mm/day, greater than the conventional treatment, of 0.852 mm/day, and a healing time of 12 days, i.e., less than the 16-day conventional treatment. The statistical analysis showed significant differences between eggshell membrane treatments and the conventional treatment.

Conclusions:

Eggshell membrane dressing and eggshell membrane powder applied to open superficial wounds in mice were more effective than the conventional treatment in regenerating injured tissue in mice.     

Analyse comparative de la séquence sexuelle chez les Ipopodes Oniscoidea de la série ligienne en relation avec le développement de la volvation chez les Armadillidiidae et les Armadillidae

A comparative study of the sexual sequence is carried out in four Oniscoidea of the ligiid series Porcellio laevis, Metoponorthus sexfasciatus (Porcellionidae), Armadillidium vulgare (Armadillidiidae) and Armadillo officinalis (Armadillidae). The differences between the four species chiefly appear in the precopulatory manoeuvres. The integration of coiling or uncoiling reactions in the sexual sequence of coiling forms is studied in two genera: Armadillidium and Armadillo. Results of the behavioral study provide information about the evolution of the group.     

Evaluación de la efectividad de la prueba rápida OptiMAL-IT™ para el seguimiento de pacientes con diagnóstico de malaria en la Amazonía peruana

Introduction:

In Peru, optical microscopy with the thick smear test continues to be performed for the follow-up of malaria patients. This test is simple but it requires microscopic equipment and suitable staff to perform the reading of the samples. Studies suggest that the rapid OptiMAL-IT™ test is an option for follow-up.

Objective:

To evaluate the effectiveness of OptiMAL-IT™ as a follow-up test in malaria patients in endemic areas of Perú.

Materials and methods:

We conducted an observational, analytical cross-sectional study of diagnostic tests performed in patients with malaria. We selected all the patients attending different health facilities in the Peruvian departments of San Martín and Loreto who met the inclusion criteria. Optical microscopy with thick smear and OptiMAL-IT™ was used on days 2, 3, 7, and 14 for Plasmodium vivax and until day 21 of follow-up for Plasmodium falciparum. Percentages of correctly classified samples and predictive values were calculated, and the results were compared between the western jungle and the eastern jungle using Chi2 or Fisher''s exact tests.

Results:

We registered 262 patients from San Martín and 302 from Loreto. The percentage of correctly classified cases and the negative predictive value were higher than 92.0% and 93,0%, respectively, from the third day of follow-up; no statistical differences were found in the results obtained from the western jungle and those from the eastern jungle.

Conclusions:

The OptiMAL-IT™ test would be effective as a follow-up test in patients diagnosed with malaria in endemic areas of Perú.     

Applications biologiques de la spectroscopie Raman de résonance et de la spectroscopie micro-Raman de résonance

Advantages are given to illustrate the possibilities of resonance Raman spectroscopy in the studies of biological systems.A relation giving the size of porphinato-core of metalloporphyrins from resonance Raman frequency is proposed. It can be applied to heme, even in lived state.By illuminating the sample through a microscope, resonance Raman effect can be collected from 1 (μm)² of sample. Spectra of a vegetal-cell wall (pimento) and of a red corpuscle (hemoglobin) are shown as examples.     

Etude de quelques propriétés de la phosphofructokinase érythrocytaire de l'homme normal

Human erythrocyte phosphofructokinase was purified 150 fold by DEAE cellulose adsorption and ammonium sulfate precipitation.At pH 7,5 the enzyme exhibits allosteric kinetics with respect to ATP, fructose 6 phosphate, and Mg²⁺.ATP at high concentration acted as an inhibitor and ADP, 5′AMP, 3′,5′, AMP, acted as activators. Both effectors seemed to decrease the homotropic interactions beetween the fructose 6 phosphate molecules.The activators increased the affinity of phosphofructokinase for the substrate (F6P), the inhibitor decreased it.These ligands had no effect on the maximum velocity of the reaction except in the case of ADP.Interactions between the substrates and the effector ligands on the enzyme were considered in terms of the Monod - Changeux - Wyman model for allosteric proteins.With GTP and ITP, no inhibition was observed. At saturing concentration of GTP, ATP still inhibited phosphofructokinase.Both 3′5′ AMP and fructose 6 phosphate increased the concentration of ATP required to produce an inhibition of 50 %.Citrate, like ATP, inhibited phosphofructokinase by binding most likely at the same allosteric site. Erythrocyte phosphofructokinase is inhibited by 2–3 DPG.The study of the relation log V max = f (pH) suggested, that the active center contains at least one imidazole and one sulfhydryl group.