Sexing single bovine blastomeres using TSPY gene amplification.

The testis-specific protein Y-encoded gene (TSPY) is a Y-specific gene present in variable copy number in many mammalian species, including cattle. We tested the applicability of the TSPY gene as a Y-specific marker to predict preimplantation embryo sex in Nelore (Bos indicus) cattle. Two blastomeres were removed from each embryo. A total of 36 single blastomeres and the remaining cells of their 18 matched in vitro conceived embryos were screened for TSPY amplification by nested-PCR. The results obtained from a single blastomere and the remaining cells of the same embryo were concordant in all cases. All blastomeres (16/16) from eight embryos produced with sexed sperm (specific for production of male embryos) were TSPY-positive. We conclude that TSPY is a good male-specific marker, the usefulness of which is probably enhanced by the high copy number. Other methods that are less time-consuming, such as real-time PCR, could be improved with the use of the TSPY gene sequences to generate primers and/or probes. This is the first report to demonstrate the applicability of the TSPY gene for sexing single cells in cattle.

Considerações sobre a idéia de tempo em Sto. Agostinho, Hume e Kant / Considerations on the idea of time in St. Augustine, Hume and Kant

Discute-se sobre o tempo buscando entendê-lo a partir dos referenciais que o tomam como elaboração subjetiva, ou seja, como não possuindo qualquer realidade fora do sujeito. Entende-se que, na história da Filosofia, esta reflexão inicia-se com a filosofia de Sto. Agostinho e tem seu ápice no pensamento moderno, sobretudo em Hume e Kant. O tempo seria uma construção ou elaboração do espírito, sem existência fora dele (Sto. Agostinho) ou uma apreensão empírica regular de relações causais de antes e depois (Hume) ou uma intuição pura do espírito (Kant). Pretende-se, com esta análise, evidenciar uma forma clássica de conceber o tempo como elaboração realizada pelo sujeito (subjetiva).

Study of the presence of the spores of Clostridium botulinum in honey in Brazil.

The isolation of Clostridium botulinum from honey samples is described. Botulism is characterized as an intoxication provoked by ingestion of contaminated foods with this toxin. Infant botulism happens by the ingestion of spores of C. botulinum together with food that in special conditions of the intestinal tract, such as those present in babies of less than 1 year old, will allow the germination and colonization of the intestine with production and absorption of botulinic toxin. The samples were subjected to dilution and to a thermal shock and cultivated in modified CMM (Difco). Cultures were subjected to Gram smears and toxicity tests in mice. The toxic cultures were purified in RFCA (Oxoid) plates and incubated in anaerobic jars. Positive samples were typed using the mouse assay neutralization test. From the 85 honey samples analyzed, six were positive for C. botulinum (7.06%), and identified as producers of type A, B, and D toxins.

Determination of Sb, Ni and V in slurry from airborne particulate material collected on filter by graphite furnace atomic absorption spectrometry.

A microdigestion procedure performed directly in the autosampler cup is proposed. Small quartz filter pieces loaded with the particulate material are transferred to the cup. The sample is digested by a mixture of nitric, sulfuric and hydrofluoric acid (1:1:1) under sonication. After the addition of a boric acid solution the elements are determined by graphite furnace atomic absorption spectrometry using the autosampler to deliver the slurry into the furnace. A mixture of palladium and magnesium nitrates was used as a modifier for Sb. Spiking studies showed recoveries close to 100% using aqueous analytical curves for Ni and Sb. For V, an analytical curve in the blank slurry, obtained by submitting an unloaded filter to the same procedure, was used. The method was applied to two standard reference materials, Coal Fly Ash (NIST 1633a) and Urban Particulate (NIST 1648) and the concentrations showed good agreement with the certified or recommended values using aqueous analytical solutions.