RESUMEN
Qanats in the aquifer of the Tehuacán Valley (Mexico) represent an ancient way of using groundwater that is still practiced today. They are used mainly for agricultural irrigation. However, anthropogenic activities have jeopardized the use of these aquifers. We analyzed 24 qanats in the Tehuacán Valley to assess water quality. Based on 24 physicochemical variables, a water quality index (WQI) was constructed on a zero-to-100 scale, divided into five water quality classes. A decision-tree analysis was applied to identify the parameters with the highest influence on the WQI, considering the water quality classes as categorical responses and the values of physicochemical variables as drivers of these categories. We produced interpolation maps to identify trends. The relationship between the WQI and the normalized difference indices of vegetation and salinity (NDVI and NDSI, respectively) was analyzed using a ternary diagram. WQI scores showed that 12.5% of the qanats have very good quality; 25%, good quality; and the remaining (62.5%) range from moderate to unacceptable quality. The CHAID classification-tree method correctly explained 83.3% of the categories, with sulfates, alkalinity, conductivity, and nitrates as the main parameters that explain water quality. WQI was inversely related to NDVI and NDSI, showing seasonal differences. Interpolation maps suggest a better water quality in the northern zone of the aquifer.
Asunto(s)
Agua Subterránea , Contaminantes Químicos del Agua , Riego Agrícola , Monitoreo del Ambiente/métodos , Agua Subterránea/análisis , México , Contaminantes Químicos del Agua/análisis , Calidad del AguaRESUMEN
Physalia physalis is a marine cnidarian from which high molecular weight toxins with hemolytic and neurotoxic effects have been isolated. In the present work, two novel toxins, PpV9.4 and PpV19.3 were purified from P. physalis by bioactive guideline isolation. It involved two steps of column chromatography, gel filtration and RP-HPLC. The molecular weights were 550.7 and 4720.9 Da for PpV9.4 and PpV19.3, respectively. In the light of the Edman sequencing results, the structure of these toxins included the presence of modified amino acids. Both toxins increased the percentage of insulin secreting beta-cells and induced cytosolic Ca2+ elevation. To date, this is the first report of low molecular weight toxins increasing insulin secretion purified from cnidarians, by constituting a new approach to the study of beta-cells physiology.
Asunto(s)
Calcio/metabolismo , Hidrozoos/metabolismo , Células Secretoras de Insulina/efectos de los fármacos , Insulina/metabolismo , Toxinas Biológicas/farmacología , Animales , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Cromatografía en Gel , Cromatografía de Fase Inversa , Hemólisis/efectos de los fármacos , Secreción de Insulina , Células Secretoras de Insulina/metabolismo , Ratas , Ratas Wistar , Toxinas Biológicas/aislamiento & purificaciónRESUMEN
Latex from Hevea brasiliensis contains several allergenic proteins that are involved in type I allergy. One of them is Hev b 2, which is a beta-1,3-glucanase enzyme that exists in different isoforms with variable glycosylation content. Two glucanase isoforms were isolated from trees of the GV-42 clone by gel filtration, affinity and ion-exchange chromatography. Isoform I had a carbohydrate content of about 20%, with N-linked N-acetyl-glucosamine, N-acetyl-galactosamine, fucose and galactose residues as the main sugars, while isoform II showed 6% carbohydrate content consisting of N-acetyl-glucosamine, fucose, mannose and xylose. Both isoforms were crystallized by the hanging-drop vapour-diffusion method. Isoform I crystals were grown using 0.2 M trisodium citrate dihydrate, 0.1 M Na HEPES pH 7.5 and 20%(v/v) 2-propanol, but these crystals were not appropriate for data collection. Isoform II crystals were obtained under two conditions and X-ray diffraction data were collected from both. In the first condition (0.2 M trisodium citrate, 0.1 M sodium cacodylate pH 6.5, 30% 2-propanol), crystals belonging to the tetragonal space group P4(1) with unit-cell parameters a = b = 150.17, c = 77.41 A were obtained. In the second condition [0.2 M ammonium acetate, 0.1 M trisodium citrate dihydrate pH 5.6, 30%(w/v) polyethylene glycol 4000] the isoform II crystals belonged to the monoclinic space group P2(1), with unit-cell parameters a = 85.08, b = 89.67, c = 101.80 A, beta = 113.6 degrees. Preliminary analysis suggests that there are four molecules of isoform II in both asymmetric units.
Asunto(s)
Alérgenos/química , Proteínas de Plantas/química , Alérgenos/genética , Alérgenos/aislamiento & purificación , Secuencia de Aminoácidos , Antígenos de Plantas , Glicoproteínas/química , Glicoproteínas/aislamiento & purificación , Hevea , Datos de Secuencia Molecular , Monosacáridos/análisis , Fragmentos de Péptidos/química , Proteínas de Plantas/genética , Proteínas de Plantas/aislamiento & purificación , Polimorfismo Genético , Isoformas de Proteínas/genética , Proteínas Recombinantes/química , Proteínas Recombinantes/aislamiento & purificación , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Difracción de Rayos XRESUMEN
In this work, the influence of an internal electric field upon the crystallization of lysozyme and thaumatin is explored using a modified design of the gel-acupuncture setup. From a crystallographic point of view, the orientation of crystals that grow preferentially over different types of electrodes inside capillary tubes is also evaluated. Finally, the crystal quality and the three-dimensional structure of these proteins grown with and without the electric field influence are analyzed by means of X-ray diffraction methods.
Asunto(s)
Cristalización/métodos , Proteínas/química , Cristalización/instrumentación , Electroquímica/métodos , Electrodos , Muramidasa/química , Proteínas de Plantas/química , Conformación Proteica , Difracción de Rayos X/métodosRESUMEN
INTRODUCTION AND OBJECTIVE: The fundus oculi is useful for observation of the interior of the eye and the retina. This study establishes a relationship between patients with established cerebral infarcts and the results observed in their fundi. PATIENTS AND METHODS: A retrospective study of the clinical histories of 177 patients seen in the rehabilitation department over a period of one year. RESULTS: The patients were aged between 29 and 85 years. The majority were men; 101 patients (57.06%) had systolic-diastolic arterial hypertension. On study of the fundus oculi there was a predominance of alterations of the blood vessels of the retina due to vascular sclerosis (93.1%) but only 24.4% had frank alterations caused by arterial hypertension. CONCLUSIONS: We found a slight relation between arterial hypertension and the alterations observed in the fundus oculi of these patients.
Asunto(s)
Fondo de Ojo , Hemiplejía/patología , Oclusión de la Arteria Retiniana/patología , Adulto , Anciano , Anciano de 80 o más Años , Arteriosclerosis/epidemiología , Arteriosclerosis/etiología , Arteriosclerosis/patología , Comorbilidad , Cuba/epidemiología , Retinopatía Diabética/complicaciones , Retinopatía Diabética/epidemiología , Retinopatía Diabética/patología , Femenino , Hemiplejía/epidemiología , Hemiplejía/etiología , Humanos , Hipertensión/complicaciones , Hipertensión/epidemiología , Masculino , Persona de Mediana Edad , Prevalencia , Oclusión de la Arteria Retiniana/etiología , Estudios Retrospectivos , Accidente Cerebrovascular/epidemiología , Accidente Cerebrovascular/etiologíaRESUMEN
To gain insight into the mechanisms of enzyme catalysis in organic solvents, the x-ray structure of some monomeric enzymes in organic solvents was determined. However, it remained to be explored whether the structure of oligomeric proteins is also amenable to such analysis. The field acquired new perspectives when it was proposed that the x-ray structure of enzymes in nonaqueous media could reveal binding sites for organic solvents that in principle could represent the starting point for drug design. Here, a crystal of the dimeric enzyme triosephosphate isomerase from the pathogenic parasite Trypanosoma cruzi was soaked and diffracted in hexane and its structure solved at 2-A resolution. Its overall structure and the dimer interface were not altered by hexane. However, there were differences in the orientation of the side chains of several amino acids, including that of the catalytic Glu-168 in one of the monomers. No hexane molecules were detected in the active site or in the dimer interface. However, three hexane molecules were identified on the surface of the protein at sites, which in the native crystal did not have water molecules. The number of water molecules in the hexane structure was higher than in the native crystal. Two hexanes localized at <4 A from residues that form the dimer interface; they were in close proximity to a site that has been considered a potential target for drug design.