Molecular identification and thermoresistance to boiling of Nocardia farcinica and Nocardia cyriacigeorgica from bovine bulk tank milk

Two strains of Nocardia spp. were isolated from bovine milk of two individual bulk tank. Molecular identification classified the strains as Nocardia farcinica and Nocardia cyriacigeorgica. The thermorresistance to boiling of the isolates was carried out and was observed bacterial growth after boiling. Our findings indicate the potential risk of pathogen transmission to humans through contaminated milk with Nocardia spp.

Estudo dos métodos de rotina diagnóstica de mastite no leite de éguas / Study of routine diagnosis methods of mastitis in mares

Routine diagnosis methods used in bovine mastitis were studied in 55 mares in lactation. The findings of strip cup test, California Mastitis Test-CMT, electronic somatic cell count-CCS, microbiological culture, and in vitro antimicrobial susceptibility profile of isolates were discussed. Streptococcus spp., Staphylococcus spp, and enterobacteria were the most common microorganisms isolated in health and CMT-positive mammary glands. Staphylococcus aureus and Arcanobacterium pyogenes were identified in two mares presenting clinical mastitis. Mean somatic cell count of eight mares without presence of microorganisms in milk was 247.57x10³/mL and 1.621,86x10³/mL in 47 mares with positive microbiological culture. Moderate concordance (63.8 percent) between positive reactions in CMT (1 to 3+) and microbiological culture was observed. Amicacin (78.9 percent), ceftiofur (74.7 percent), sulpha-trimetoprim (69,0 percent) and norfloxacin (69.0 percent), were the most effective drugs, while resistance of isolates was mainly observed against penicillin (64.8 percent), gentamycin (35.2 percent), azithromycin (35.2 percent), enrofloxacin (28.2 percent), and florfenicol (28.2 percent).

Development of bovine embryos reconstructed by nuclear transfer of transfected and non-transfected adult fibroblast cells

An association of two techniques, nuclear transfer (NT), and transfection of somatic animal cells, has numerous potential applications and considerable impact, mainly in agriculture, medicine, pharmacy, and fundamental biology. In addition, somatic cell nuclear transfer is the most efficient alternative to produce large transgenic animals. We compared in vitro and in vivo developmental capacities of NT using fibroblast cells isolated from a 14-month-old cloned Simmental heifer (FCE) vs the same line transfected with a plasmid containing neomycin-resistant genes (TFCE). There were no significant differences (P > 0.5) in either fusion (116/149 = 78% vs 216/301 = 72%), cleavage (78/116 = 67% vs 141/216 = 65%) and blastocyst (35/116 = 30% vs 52/216 = 24%) rates or in pregnancy rate at 30 to 35 days after embryo transfer (2/17 vs 3/17) between NT using FCE and TFCE, respectively. Transfection and long-term in vitro culture of transfected cells did not affect developmental capacity of NT embryos up to 40 days of gestation

Isolation of transfected fibroblast clones for use in nuclear transfer and transgene detection in cattle embryos

Transgenesis in cattle has provided numerous opportunities for livestock production. The development of nuclear transfer (NT) technology has improved the production of transgenic livestock. However, the isolation of pure colonies from a single transfection event remains laborious and can be a constraint in the production of transgenic livestock. We used 96-well cell culture plates to isolate cell lineages obtained from a single fibroblast transfected with the pCi-Neo plasmid. Since single mammalian cells do not grow well in fresh medium, we evaluated the use of conditioned medium. The neomycin phosphotransferase gene was detected in isolated colonies and NT embryos were produced from these cells. Multiplex-PCR assays were performed to detect the transfected fragment as well as autosomal satellite DNA in single NT embryos. This approach provided a reliable method for isolating transfected mammalian cells and for diagnosing the incorporation of desirable vectors in NT embryos. This method can reduce the time and cost of transgenic livestock production.