Abstract:

La muerte de equinos con cuadros clínicos de cólico es frecuente, especialmente en animales estabulados y con fines deportivos. Sin embargo, al ser muy bajo el porcentaje de animales que son necropsiados y muestreados, la mayoría de los casos queda con un diagnóstico incierto, que impide establecer la causa de muerte. En el presente trabajo se presentan y analizan los hallazgos clínicos, histopatológicos y bacteriológicos de un equino que muere a las 48 h con un cuadro clínico de cólico. A la necropsia los hallazgos más importantes fueron ruptura del estómago, intestino delgado color rojo oscuro con la pared aumentada de espesor y el hígado color amarillento y aspecto de nuez moscada. De los cultivos anaeróbicos de hígado se aisló Clostridium perfringens tipo A. Si bien el rol de C. perfringens en infecciones intestinales en equinos es motivo de controversias, en este caso se aporta información sobre la posible relación entre la presencia de esta bacteria y casos de enteritis hemorrágicas severas o enterotoxemias en equinos. Se alerta sobre la posibilidad de que las enteritis hemorrágicas sean más frecuentes de lo esperado y por ende la necesidad de estudiarlas en mayor profundidad.

The death of horses with clinical symptoms of colic is common, especially in confined and for sport animals. Since a small percentage of death horses due to colics are necropsied and sampled, it prevents Vets to reach a final diagnosis and to establish the cause of death. The aim of the present work was to describe the clinical, histopathological and bacteriological findings of a horse that died after having colics. The most important findings observed during necropsy were rupture of the stomach, dark red colour of the small intestine with increased wall thickness and a yellowish colour of the liver with nutmeg appearance. Clostridium perfringens type A was isolated from the liver. While the role of C. perfringens in intestinal infections in horses is controversial, in this case information on the possible relationship between the presence of this bacterium in cases of severe hemorrhagic enteritis or enterotoxemias in horses is provided. It is possible that hemorrhagic enteritis is more frequent than expected; therefore there is a need to be alert on the occurrence of this disease in horses with colics.

Estación Experimental Agropecuaria Bariloche

Author affiliation: Robles, Carlos Alejandro. INTA. Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Grupo Salud Animal; Argentina

Author affiliation: Paván, María Elisa. Biochemiq S.A. Laboratorio de Biología Molecular; Argentina

Author affiliation: Chapero, Claudio. Consultor Privado. Bariloche; Argentina

Author affiliation: Marcellino, Romanela. INTA. Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Grupo Salud Animal; Argentina

Author affiliation: Cairó, Fabián A. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina

Author affiliation: Mignaqui, Ana Clara. INTA. Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Grupo Salud Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

Bacillus anthracis protective antigen (PA) is a well known and relevant immunogenicprotein that is the basis for both anthrax vaccines and diagnostic methods. Properly foldedantigenic PA is necessary for these applications. In this study a high level of PA was obtained inrecombinant Escherichia coli. The protein was initially accumulated in inclusion bodies, whichfacilitated its efficient purification by simple washing steps; however, it could not be recognizedby specific antibodies. Refolding conditions were subsequently analyzed in a high-throughputmanner that enabled nearly a hundred different conditions to be tested simultaneously. Therecovery of the ability of PA to be recognized by antibodies was screened by dot blot usinga coefficient that provided a measure of properly refolded protein levels with a high degreeof discrimination. The best refolding conditions resulted in a tenfold increase in the intensityof the dot blot compared to the control. The only refolding additive that consistently yieldedgood results was L-arginine. The statistical analysis identified both cooperative and negativeinteractions between the different refolding additives. The high-throughput approach describedin this study that enabled overproduction, purification and refolding of PA in a simple andstraightforward manner, can be potentially useful for the rapid screening of adequate refoldingconditions for other overexpressed antigenic proteins.

Author affiliation: Pavan, María Elisa. Biochemiq; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Author affiliation: Pavan, Esteban E.. Politecnico di Milano; Italia

Author affiliation: Cairo, Fabian Martin. Biochemiq; Argentina

Author affiliation: Pettinari, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

Abstract:

The genome of Aeromonas salmonicida subsp. pectinolytica strain 34melT, isolated from a heavily polluted river, contains several genomic islands and putative virulence genes. The identification of genes involved in resistance to different kinds of stress sheds light on the mechanisms used by this strain to thrive in an extreme environment.

Author affiliation: Pavan, María Elisa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Author affiliation: Pavan, Esteban E.. Politecnico di Milano; Italia

Author affiliation: López, Nancy Irene. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina

Author affiliation: Levin, Laura Noemí. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Pettinari, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Abstract:

Leptospirosis is the most widespread zoonosis in the world and significant efforts have been made to determine and classify pathogenic Leptospira strains. This zoonosis is maintained in nature through chronic renal infections of carrier animals, with rodents and other small mammals serving as the most important reservoirs. Additionally, domestic animals, such as livestock and dogs, are significant sources of human infection. In this study, a multiple-locus variable-number tandem repeat analysis (MLVA) was applied to genotype 22 pathogenic Leptospira strains isolated from urban and periurban rodent populations from different regions of Argentina. Three MLVA profiles were identified in strains belonging to the species Leptospira interrogans (serovars Icterohaemorrhagiae and Canicola); one profile was observed in serovar Icterohaemorrhagiae and two MLVA profiles were observed in isolates of serovars Canicola and Portlandvere. All strains belonging to Leptospira borgpetersenii serovar Castellonis exhibited the same MLVA profile. Four different genotypes were isolated from urban populations of rodents, including both mice and rats and two different genotypes were isolated from periurban populations.

Author affiliation: Grune Loffler, Sylvia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina

Author affiliation: Pavan, María Elisa. Biochemiq SA; Argentina

Author affiliation: Vanasco, Norma Bibiana. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorios e Instituto de Salud "Dr. C. G. Malbran". Instituto Nacional de Enfermedades Respiratorias; Argentina

Author affiliation: Samartino, Luis Ernesto. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Universidad del Salvador; Argentina

Author affiliation: Suarez, Olga Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina

Author affiliation: Auteri, Carmelo. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina

Author affiliation: Romero, Graciela. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina

Author affiliation: Brihuega, Bibiana. Universidad del Salvador; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina

Abstract:

Leptospirosis outbreaks occur regularly in Argentina and other South American countries, but little is known about their epidemiological relationships. Application of new molecular tools, such as the Multiple-Locus Variable-number tandem repeat Analysis (MLVA) is limited by scant available data on regional strains. We have analyzed the genetic diversity of a collection of 31 strains of Leptospira interrogans isolated in Argentina during the past five decades from humans and animals, including a strain from an environmental source and another isolated from an opossum. Genotyping was performed by MLVA using the loci VNTR4, VNTR7, VNTR9, VNTR10, VNTR19, VNTR23 and VNTR31, as described by Majed et al. [Identification of variable-number tandem-repeat loci in Leptospira interrogans sensu stricto. J Clin Microbiol 2005;43:539-45 [1]]. Clustering analysis revealed eight distinct MLVA genotypes, with a dominant one, genotype A. Strains with this genotype were consistently isolated since 1960, representing 55% of the total strains and spanning an extensive geographical distribution. Other seven genotypes were less frequent, and only genotypes A and Hond Utrecht IV were isolated during the last decade. Different kinds of repeat blocks for each VNTR locus were identified by sequence analysis. VNTR copy number differences among genotypes always involved only one of these blocks. MLVA patterns obtained reveal the genetic diversity and relationships between strains, and constitute the framework for the genotyping of leptospires in the region. © 2010 Elsevier Ltd.

Author affiliation: Pavan, María Elisa. Biochemiq S.A.; Argentina

Author affiliation: Cairo, Fabian Martin. Biochemiq S.A.; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina

Author affiliation: Pettinari, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Author affiliation: Samartino, Luis Ernesto. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas; Argentina. Universidad del Salvador; Argentina

Author affiliation: Brihuega, Bibiana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas; Argentina. Universidad del Salvador; Argentina

Abstract:

Caseous lymphadenitis, caused by Corynebacterium pseudotuberculosis, has a high prevalence in many regions of the world, including Argentina and Brazil. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for the identification of this microorganism was designed based on the hypervariable region of the polymorphic RNA polymerase β-subunit gene (rpoB). All available Corynebacterium rpoB sequences were analyzed by computer-assisted restriction analysis. The rpoB PCR-RFLP pattern predicted by using endonucleases MseI and StuI clearly differentiated C. pseudotuberculosis from sixty-one other Corynebacterium species. This method was successfully applied to identify twelve wild C. pseudotuberculosis ovine isolates and one caprine isolate. It was also used to differentiate C. pseudotuberculosis from Arcanobacterium pyogenes, an ovine pathogen with similar clinical characteristics. These results indicate that this new molecular method can be used for the reliable identification of the pathogen, essential for the timely detection of infected animals and for epidemiological studies. © 2011 Elsevier Ltd.

Author affiliation: Pavan, María Elisa. Biochemiq S.A.; Argentina

Author affiliation: Robles, Carlos Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina

Author affiliation: Cairo, Fabian Martin. Biochemiq S.A.; Argentina

Author affiliation: Marcellino, R.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina

Author affiliation: Pettinari, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Abstract:

Caseous lymphadenitis, caused by Corynebacterium pseudotuberculosis, has a high prevalence in many regions of the world, including Argentina and Brazil. A polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method for the identification of this microorganism was designed based on the hypervariable region of the polymorphic RNA polymerase b-subunit gene (rpoB). All available Corynebacterium rpoB sequences were analyzed by computer-assisted restriction analysis. The rpoB PCR–RFLP pattern predicted by using endonucleases MseI and StuI clearly differentiated C. pseudotuberculosis from sixty-one other Corynebacterium species. This method was successfully applied to identify twelve wild C. pseudotuberculosis ovine isolates and one caprine isolate. It was also used to differentiate C. pseudotuberculosis from Arcanobacterium pyogenes, an ovine pathogen with similar clinical characteristics. These results indicate that this new molecular method can be used for the reliable identification of the pathogen, essential for the timely detection of infected animals and for epidemiological studies.

Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Grupo de Salud Animal

Author affiliation: Paván, María Elisa. Biochemiq S.A. Laboratorio de Biología Molecular; Argentina

Author affiliation: Robles, Carlos Alejandro. INTA. Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Grupo Salud Animal; Argentina

Author affiliation: Cairó, Fabián A. Biochemiq S.A. Laboratorio de Biología Molecular; Argentina

Author affiliation: Marcellino, Romanela. INTA. Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Grupo Salud Animal; Argentina

FiL: Pettinari, María Julia. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Abstract:

Aeromonas salmonicida subsp. pectinolytica 34melT can be considered an extremophile due to the characteristics of the heavily polluted river from which it was isolated. While four subspecies of A. salmonicida are known fish pathogens, 34melT belongs to the only subspecies isolated solely from the environment. Genome analysis revealed high metabolic versatility, the capability to cope with diverse stress agents, and the lack of several virulence factors found in pathogenic Aeromonas. The most relevant phenotypic characteristics of 34melT are pectin degradation, a distinctive trait of the pectinolytica subspecies, and melanin production. Genes coding for three pectate lyases were detected in a cluster unique for this microorganism, that contains all genes needed for pectin degradation. Melanin synthesis in 34melT is hypothesized to occur through the homogentisate pathway, as no tyrosinases or laccases were detected, and the homogentisate 1,2-dioxygenase gene is inactivated by a transposon insertion, leading to the accumulation of the melanin precursor homogentisate. Comparative genome analysis of other melanogenic Aeromonas revealed that this gene was inactivated by transposon insertions or point mutations, indicating that melanin biosynthesis in Aeromonas occurs through the homogentisate pathway. Horizontal gene transfer could have contributed to the adaptation of 34melT to a highly polluted environment, as thirteen genomic islands were identified in its genome, some of them containing genes coding for fitness related traits. Heavy metal resistance genes, along with others associated to oxidative and nitrosative stress were also found. These characteristics, together with melanin production and the ability to use different substrates, could explain the capability of this microorganism to live in an extremely polluted environment.

Author affiliation: Pavan, María Elisa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Author affiliation: Pavan, Esteban E.. Politecnico Di Milano; Italia

Author affiliation: Lopez, Nancy Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue. Laboratorio de Investigaciones Bioquímicas y Químicas del Ambiente | Universidad Nacional del Comahue. Facultad de Ciencias Agrarias. Centro de Investigaciones en Toxicología Ambiental y Agrobiotecnología del Comahue. Laboratorio de Investigaciones Bioquímicas y Químicas del Ambiente; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina

Author affiliation: Levin, Laura Noemi. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina

Author affiliation: Pettinari, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigaciones En Toxicología Ambiental y Agrobiotecnología del Comahue. Laboratorio de Investigaciones Bioquímicas y Químicas del Ambiente | Universidad Nacional del Comahue. Facultad de Cs.agrarias. Centro de Investigaciones En Toxicología Ambiental y Agrobiotecnología del Comahue. Laboratorio de Investigaciones Bioquímicas y Químicas del Ambiente; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentina