Crystal Structure of the Cysteine-Rich Domain of Mannose Receptor Complexed with a Sulfated Carbohydrate Ligand

The macrophage and epithelial cell mannose receptor (MR) binds carbohydrates on foreign and host molecules. Two portions of MR recognize carbohydrates: tandemly arranged C-type lectin domains facilitate carbohydrate-dependent macrophage uptake of infectious organisms, and the NH2-terminal cysteine-rich domain (Cys-MR) binds to sulfated glycoproteins including pituitary hormones. To elucidate the mechanism of sulfated carbohydrate recognition, we determined crystal structures of Cys-MR alone and complexed with 4-sulfated-N-acetylgalactosamine at 1.7 and 2.2 Å resolution, respectively. Cys-MR folds into an approximately three-fold symmetric β-trefoil shape resembling fibroblast growth factor. The sulfate portions of 4-sulfated-N-acetylgalactosamine and an unidentified ligand found in the native crystals bind in a neutral pocket in the third lobe. We use the structures to rationalize the carbohydrate binding specificities of Cys-MR and compare the recognition properties of Cys-MR with other β-trefoil proteins

Assessment of the diagnostic accuracy of bacteriological culture and the invA-gen-based PCR for the detection of Salmonella organisms from caecal content from slaughtered pigs through Bayesian approaches

The goal of this study was to determine the accuracy of a culture technique and the invA-gen-based PCR, for the detection of Salmonella spp. From caecal samples from slaughtered pigs. For this purpose a Bayesian approach was used. Two hundred and three pigs were used. Animals were grouped into 2 populations: 96 from small farms and 107 from large farms. Sensitivity was 56% (95% Credible Interval: 40-76) for culture and 91% (95% CI: 81-97) for PCR

Características de tres pastizales bajos con distinto periodo de descanso

In an upland region with short grassland in the Dpto Loventué- La Pampa (Lat-.36°50' S Long.65°18' W) we compared three areas-. Two of them were exclosures of 28 and 14 years; the third had a rest of twelve months every other year. The three communities were similar in floristic composition but different in the values of abundance-cover of their principal species. Vegetation cover had a maximum in the exclosures and a minimum in the area that had a rest of twelve months every other year. In the three areas the frequency of dominants and codominants species ranged among 90-100%. Standing crop reached 320 gMS/m2 in the oldest exclosure and 150 gMS/m2 in the area with a rest of twelve months every other year. Flower stalk numbers, culm lenght and crown diameter were great in the 14 years exclosure·.koeleria permollis a decreaser palatable specie was codominant only in the 28 years exclosure. Poa ligularis another decreaser desiderable specie codominated in the 14 years exclosure. In the area with a rest of twelve months every other year was dominant Piptochaetium.En una región con pastizal bajo del departamento, La Pampa (lat·.36°50' S Long'. 65°18' W) se analizaron las diferencias entre tres áreas. Dos de ellas eran clausuras de 28 y 14 años. La tercera tuvo en los últimos años un descanso de doce meses, año por medio. Las tres áreas son similares en composición florística, pero difieren en los valores de abundancia-cobertura de sus especies principales. La cobertura de la vegetación tuvo un máximo en las dos clausuras y un mínimo en el área con descanso de doce meses, año por medio. La frecuencia de las especies dominantes y codominantes vario del 90 al 100%. La fitomasa aérea alcanzó a 320 gMS/m2 en el área no pastoreada durante 28 años y de150 gMS/m2 en el área con un descanso anual, año por medio. Los valores de altura de cañas, altura verde y diámetro de corona fueron mayores en la clausura de 14 años. Koeleria permollis una especie decreciente codominó solamente en la clausura de 28 años. Poa ligularis otra especie decreciente, deseable, codominó en la clausura de 14 años y Piptochaetium napostaense domino en el área con un descanso de doce meses, año por medio

Determinación de proteína bruta de algunas especies forrajeras de La Pampa

This work took place in three different grasslands in the Province of La Pampa. The first, located in LAS MERCEDES farm, departament of TOAY, with predominane of Digitaria californica. This warm season species reached 14,4% of crude protein (CP) at the beginning of growing season. LA BAYA VIEJA farm was the second place under study, with predominance of winter season species such as Poa ligularis, Piptochaetium napostaense on which 8,5% and 12,4% of CP were obtained respectively in the grow out after cutting. The third place was LOS GUADALES farm, depatament of CALEU CALEU with predominance, of Pappophorum caespitosum during summer and Medicago minima and Erodium cicutarium in winter, wich resulted 9,8%, 24,8% and 23,8% of CP respectively at the beginning of growing season.Este trabajo se realizó en tres pastizales diferentes de la provincia de La Pampa. El primero ubicado en la Ea. La Mercedes, Depto. Toay, presenta dominancia de Digitaria californica, especie de verano en la que se obtuvo 14,4% de PB. al comienzo de su período productivo. El segundo pastizal estudiado está ubicado en la Ea. La Baya Vieja, Depto. Toay, con predominio de especies invernales como Poa ligularis y Piptochaetium napostaense, en la que se obtuvieron valores de 8,5% y 12,4% de PB. respectivamente al inciarse el rebrote. El tercer pastizal estudiado está ubicado en la Ea. Los Guadales, Depto. Caleu-Caleu, con predominio de Pappophorum caespitosum en verano y con Medicago minima y Erodium cicutarium en invierno, especies en las que se obtuvieron los valores 9,8%, 24,8 y 23,8% de PB. respectivamente al iniciarse la brotación

Crystallization and X-ray Structure Determination of Cytochrome c_2 from Rhodobacter sphaeroides in Three Crystal Forms

Cytochrome c_2 serves as the secondary electron donor that reduces the photo-oxidized bacteriochlorophyll dimer in photosynthetic bacteria. Cytochrome c_2 from Rhodobacter sphaeroides has been crystallized in three different forms. At high ionic strength, crystals of a hexagonal space group (P6_122) were obtained, while at low ionic strength, triclinic (P1) and tetragonal (P4_12_12) crystals were formed. The three-dimensional structures of the cytochrome in all three crystal forms have been determined by X-ray diffraction at resolutions of 2.20 Å (hexagonal), 1.95 Å, (triclinic) and 1.53 Å (tetragonal). The most significant difference observed was the binding of an imidazole molecule to the iron atom of the heme group in the hexagonal structure. This binding displaces the sulfur atom of Met 100, which forms the axial ligand in the triclinic and tetragonal structures

Presence of Clostridium difficile in pig faecal samples and wild animal species associated with pig farms

Aims: to determine the presence of Clostridium difficile on fattening pig farms in north-eastern Spain. Methods and results: Twenty-seven farms were sampled. Pools of pig faecal samples (n = 210), samples of intestinal content from common farm pest species (n = 95) and environment-related samples (n = 93) were collected. Isolates were tested for toxin genes of C. difficile, and typed by PCR-ribotyping and toxinotyping. The minimal inhibitory concentrations of six antimicrobial agents were determined using Etest. Thirty-four isolates were obtained from 12 farms, and 30 (88·2%) had toxin genes. Seven ribotypes were identified. Ribotype 078 and its variant 126 were predominant (52·9%). The same ribotypes were isolated from different animal species on the same farm. None of the isolates were resistant to metronidazole or vancomycin. Conclusions: Clostridium difficile was common within the pig farm environment. Most of the positive samples came from pest species or were pest-related environmental samples. Significance and Impact of the Study: Pest species were colonized with toxigenic and antimicrobial-resistant C. difficile strains of the same ribotypes that are found in humans and pigs. Rodents and pigeons may transmit toxigenic and antimicrobial-resistant C. difficile strains that are of the same ribotypes as those occuring in humans

Estados de condición del sitio pastizal de gramíneas bajas de planicie presentes en el departamento Loventué La Pampa

It has been evaluating range condition in twenty areas of shortgrasslands in Loventué - La Pampa. The state Condition's identification was realized with the standing - crop's dates. Frequency, density, cover and height of principal’s species were taken. The following indices were used to classified the grassland's Condition: Very Good; Good, Fair, Poor and Very Poor.Se evaluó la condición de pastura en 20 áreas de pastizal de planicie en el Departamento Loventué, La Pampa. La identificación del estado de condición se realizó en función del peso de las especies por unidad de muestreo. Se hicieron además determinaciones de frecuencia, densidad, cobertura y altura de las especies más importantes. Para la determinación de la condición de las áreas, fueron usados los siguientes índices: Muy buena. Buena, Regular, Mala y Muy Mala

Detection of hepatitis viral E in clinical samples using real time methodology

El virus dela Hepatitis E (HEV) es trans-mitido a través de una ruta fecal-oral en áreas endémi-cas fundamentalmente por la ingesta de agua conta-minada y aunque la vía zoonótica está bien definida, la seroprevalencia en nuestra región debe aún ser esta-blecida. Este patógeno es de relevancia sanitaria fun-damentalmente entre las embarazadas, los trasplanta-dos y los pacientes inmunocomprometidos, por lo que desarrollar métodos diagnósticos rápidos, sensibles y específicos nos brinda la oportunidad de aplicar medi-das terapéuticas y preventivas apropiadas

Persistencia de los cambios provocados por los fuegos controlados en diferentes estructuras del bosque de caldén (Prosopis caldenia Burk.)

Fire may be reintroducted as prescribed burns for different purposes, mainly to remove accumulated fuels and the risk of intense fires or as a tool of range management in order to improve the forage offer. The objective of this study was to assess the vegetation response to burning 6 and 12 months after precribed fires in two different caldén woodlands: open woodland (BA) associated with torage species, and closed forest (BD) with a poor proportion of forage species a) in the community b) in the seed bank. The effect of prescribed burn in this study had less impact on the vegetation structure of both communities than expected, in terms of reduction of non palatable woody species and increasing of forage species abundance. The vegetation response is principally influenced by ils structural and floristic characteristics.La reintroducción del fuego en forma de quema prescriptas puede tener diferentes finalidades. El uso más frecuente es para la reducción de fitomasa altamente combustible, disminuyendo de esta manera los riesgos de propagación de incendio o como herramienta para mantener o aumentar la producción forrajera de las áreas. El objetivo del presente trabajo es evaluar la respuesta de la vegetación a la acción de la quema controlada en los 6 y 12 meses posteriores a la misma en dos variantes de la comunidad de bosque de caldén: bosque abierto (BA) con presencia de especies forrajeras y bosque denso (BD) con baja proporción de especies forrajeras a) en la vegetación b) en el banco de semillas de gramíneas. El efecto del fuego controlado observado en este trabajo para ambas comunidades no tuvo la magnitud de cambio estructural que se esperaba en lo que respecta a aumento de forrajeras y disminución de especies no forrajeras y leñosas. La respuesta de la vegetación estuvo principalmente condicionada por las características estructurales y florísticas de la comunidad

Structure of the Reaction Center from Rhodopseudomonas sphaeroides R-26 and 2.4.1: Protein-Cofactor (Bacteriochlorophyll, Bacteriopheophytin and Carotenoid) Interactions

The three-dimensional structures of the cofactors and protein subunits of the reaction center (RC) from the carotenoidless mutant strain of Rhodobacter sphaeroides R-26 and the wild-type strain 2.4.1 have been determined by x-ray diffraction to resolutions of 2.8 Å and 3.0 Å with R values of 24% and 26%, respectively. The bacteriochlorophyll dimer (D), bacteriochlorophyll monomers (B), and bacteriopheophytin monomers (φ) form two branches, A and B, that are approximately related by a twofold symmetry axis. The cofactors are located in hydrophobic environments formed by the L and M subunits. Differences in the cofactor-protein interactions between the A and B cofactors, as well as between the corresponding cofactors of Rb, sphaeroides and Rhodopseudomonas viridis [Michel, H., Epp, O. & Deisenhofer, J. (1986) EMBO J. 3, 2445-2451], are delineated. The roles of several structural features in the preferential electron transfer along the A branch are discussed. Two bound detergent molecules of beta-octyl glucoside have been located near B_A and B_B. The environment of the carotenoid, C, that is present in RCs from Rb. sphaeroides 2.4.1 consists largely of aromatic residues of the M subunit. A role of B_B in the triplet energy transfer from D to C and the reason for the preferential ease of removal of B_B from the RC is proposed