RESUMEN
Incidence of unusually high numbers of stillbirths was observed at a piggery unit at the Veterinary University research farm in Tamil Nadu State of India. Systematic examination of the tissue from stillborn piglets led to the identification of presence of Porcine circovirus 2 (PCV2). Detailed analysis utilizing electron microscopy, polymerase chain reaction and sequencing confirmed the presence of PCV2 in the tissue of affected piglets. Histopathology analysis of the affected piglet tissue showed lymphoid cell depletion of lymphnodes, spleen and infiltration of liver, kidney, myocardium, etc. Retrospective examination of the morbidity and mortality history in the farm revealed high mortality in young and weanling piglets suggestive of PCV2 infection-induced diseases. This is the first report of emergence of major disease incidence in farmed swine due to PCV2 infection in India.
Asunto(s)
Infecciones por Circoviridae/veterinaria , Circovirus/fisiología , Mortinato/veterinaria , Enfermedades de los Porcinos/epidemiología , Animales , Infecciones por Circoviridae/epidemiología , Infecciones por Circoviridae/virología , Circovirus/genética , Genes Virales , Incidencia , India/epidemiología , Microscopía Electrónica de Transmisión/veterinaria , Sistemas de Lectura Abierta , Especificidad de Órganos , Filogenia , Reacción en Cadena de la Polimerasa/veterinaria , Estudios Retrospectivos , Análisis de Secuencia de ADN/veterinaria , Mortinato/epidemiología , Porcinos , Enfermedades de los Porcinos/virologíaRESUMEN
A simple and concomitant esterification method for the synthesis of methyl, ethyl, t-butyl, benzyl, and 9-fluorenylmethyl esters of Fmoc-/Boc-/Z-beta-homoamino acids employing Fmoc-/Boc-/Z-alpha-aminodiazoketones by Wolff rearrangement is described. The method offers good yield with purity.
Asunto(s)
Aminoácidos/síntesis química , Ésteres/síntesis química , Cetonas/química , Alquilación , Aminoácidos/química , Ésteres/químicaRESUMEN
A beta-hairpin conformation has been characterized in crystals of the decapeptide t-butoxycarbonyl-Leu-Val-beta Phe-Val-(D)Pro-Gly-Leu-beta Phe-Val-Val-methyl ester [beta Phe; (S)-beta(3) homophenylalanine] by x-ray diffraction. The polypeptide chain reversal is nucleated by the centrally positioned (D)Pro-Gly segment, which adopts a type-I' beta-turn conformation. Four intramolecular cross-strand hydrogen bonds stabilize the peptide fold. The beta Phe(3) and beta Phe(8) residues occupy facing positions on the hairpin, with the side chains projecting on opposite faces of the beta-sheet. At the site of insertion of beta-residues, the polarity of the peptide units along each strand reverses, as compared with the alpha-peptide segments. In this analog, a small segment of a polar sheet is observed, where adjacent CO and NH groups line up in opposite directions in each strand. In the crystal, an extended beta-sheet is formed by hydrogen bonding between strands of antiparallel pairs of beta-hairpins. The crystallographic parameters for C(65)H(102)N(10)O(13) x 3H(2)O are: space group P2(1)2(1)2(1); a = 19.059(8) A, b = 19.470(2) A, c = 21.077(2) A; Z = 4; agreement factor R(1) = 9.12% for 3,984 data observed >4 sigma(F) and a resolution of 0.90 A.
Asunto(s)
Péptidos/química , Fenilalanina/química , Aminoácidos/química , Conformación Molecular , Péptidos/síntesis química , EstereoisomerismoRESUMEN
A new and efficient method for the synthesis of N(alpha)-Fmoc-/Boc-/Z-beta-amino acids using the two-step Arndt-Eistert approach is described. Fmoc-/Boc-/Z-alpha-Amino acid fluorides were used for the acylation of diazomethane synthesizing Fmoc-/Boc-/Z-alpha-aminodiazoketones as crystalline solids with good yield and purity. They were then converted to the corresponding beta-amino acids using PhCOOAg/dioxane/H2O.
Asunto(s)
Aminoácidos/síntesis química , Fluorenos/síntesis química , Acilación , Aminoácidos/química , Diazometano/química , Fluorenos/química , Flúor/química , EstereoisomerismoRESUMEN
A range of N(alpha)-Fmoc-protected amino acids, including those that contain t-butyl moiety, have been synthesized by employing Fmoc-Cl utilizing the activated, commercial zinc dust-promoted synthesis of carbamates under neutral conditions. A general procedure is described that circumvents the oligomerization side reaction normally noticed in Schotten-Baumann conditions. It is a simple, convenient and clean method. Thus, Fmoc-amino acids are obtained in high yield (85-92%) and purity as checked by thin-layer chromatography, high-performance liquid chromatography and other physical methods.
Asunto(s)
Aminoácidos/síntesis química , Fluorenos/síntesis química , Acilación , Aminoácidos/química , Carbamatos/química , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Fluorenos/química , ZincRESUMEN
The homologation of alpha-amino acids to beta-amino acids by the two-step Arndt-Eister method is achieved by using Fmoc-alpha-amino acid pentafluorophenyl esters for the acylation of diazomethane, synthesizing the key intermediates Fmoc-aminoacyldiazomethanes as crystalline solids in good yields and purity.