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Existe una gran posibilidad de mejorar la producción de embriones in vitro al enriquecer los medios de cultivo adicionando moléculas que regulen las condiciones óptimas de los gametos. El objetivo de este estudio fue adicionar la proteína de choque térmico recombinante HSC70, para evaluar su efecto en la producción de embriones in vitro. Se adicionaron 25 ng/mL de la proteína HSC70 al cultivo de embriones sometidos a estrés térmico, formando cuatro tratamientos T1= medio adicionado con HSC70 a 41 °C, T2= medio sin HSC70 a 41 °C, T3= medio adicionado con HSPC70 a 38.5 °C y T4= medio sin HSC70 a 38.5 °C. Bajo el protocolo de producción in vitro de embriones bovino en los medios de cultivo temprano (CDM1) y tardío (CDM2), con la finalidad de evaluar el desarrollo embrionario a través de las variables, porcentaje de división embrionaria, embriones de seis células o más y blastocistos al día 7 u 8 y número de células en blastocisto al día 7. El conteo de las células en los blastocitos al día 7 del cultivo, se llevó a cabo a través del protocolo de tinción diferencial de Hoescht 33342. Los datos se sometieron a un análisis de varianza con un arreglo factorial con el procedimiento GLM de SAS (2013), que incluyó los factores de proteína, temperatura y su interacción. El número de células se analizó asumiendo una distribución Poisson por tratarse de un conteo. Los resultados mostraron que el factor proteína fue significativa (p= 0.01) para todas las variables de respuesta y existe un efecto positivo de la proteína HSC70, agregada al medio de cultivo, sin importar la temperatura a la que fueron cultivados; este efecto se expresó tanto en un mayor porcentaje de embriones, como en una mayor tasa (p

The genetic variability of S. aureus strains isolated from some cases of bovine mastitis was determined. 335 cows from 27 stables were sampled in 10 municipalities in the state of Jalisco. S. aureus strains were identified from milk samples of each mammary gland of each cow, which were grown in blood agar and based on the characteristics of the culture, biochemical tests, and finally their molecular confirmation by PCR. The genetic variation in the strains was identified by pulsed- field electrophoresis technique. The images of the gels were analyzed using the Bionumerics® software. 2.26% of clinical mastitis and 40.45% of subclinical mastitis were diagnosed with the California test. A frequency of appearance of S. aureus of 9.8% of the total sampled glands was recorded. A genetic variation of 14.9% was observed. The 32 strains analyzed were grouped into pulsotypes with 95% or more of genetic similarity, resulting in 12 pulsotypes. It is concluded that there is great diversity in the genetic variability of S. aureus strains from different stables in the state of Jalisco and a great genetic similarity of strains within each stable.

Bovine tuberculosis (bTB) remains a problem on many dairy farms in Mexico, as well as a public health risk. We previously found a high frequency ofMycobacterium bovisDNA in colostrum from dairy cows using a nested PCR to detectmpb70. Since there are no reliablein vivotests to determine the effectiveness of boosterMycobacterium bovisBCG vaccination against bTB, in this work we monitoredM. bovisDNA in colostrum by using this nested PCR. In order to decrease the risk of adverse reactions in animals likely containing viableM. bovis, a single application of BCG and a subunit vaccine (EEP-1) formulated withM. bovisculture filtrate proteins (CFP) and a copolymer as the adjuvant was performed in tuberculin skin test-negative cattle (TST−), while TST reactor animals (TST+) received EEP-1 only. Booster immunization using EEP-1 was applied to both groups, 2 months after primary vaccination to whole herds and 12 months later to lactating cows. Colostrum samples were collected from 6 farms where the cows were vaccinated over a 12-month period postvaccination and, for comparison, from one control farm where the cows were not vaccinated with comparable bTB prevalence. We observed an inverse relationship between the frequency ofM. bovisDNA detection and time postvaccination at the first (P< 0.001) and second (P< 0.0001) 6-month periods. Additionally, the concentration of gamma interferon (IFN-γ) was higher inmpb70PCR-positive colostrum samples (P= 0.0003). These results suggest thatM. bovisDNA frequency in colostrum could be a potentially useful biomarker for bTB vaccine efficacy on commercial dairy farms.

The objective of this study was to identify the presence of Mycobacterium tuberculosis complex bacterial DNA in samples extracted from fresh cheeses; 95 samples of fresh cheese were obtained from municipal markets in the state of Hidalgo, in central Mexico, and were analyzed in triplicate. The exogenous control for the amplification was the mitochondrial gene for cytochrome b (cyt-b). M. tuberculosis complex DNA was detected by nested-PCR amplification of a fragment of the mpb70 gene in six samples, four of which were obtained from regions with enzootic bovine tuberculosis. These results suggest that cheeses prepared with raw milk contaminated with M. bovis are being sold and consumed by humans, which may cause tuberculosis.

Andalusia, the southern region of Spain, has an ancient history, magnificent monuments and a prolific culture. This region has developed an ambitious infrastructure improving plan, concerning every facility and mean of transport. Bridges have a preeminent role in all of these interventions, and their design needs to deal, in a very conscious way, with a rich natural environment and with an outstanding cultural heritage that configure the historic patrimony of the area. For all these reasons, it is appealing to analyse how to develop a bridge project in such an attractive and, at the same time, sensitive environment, especially in urban areas where the conjunction of nature and cultural heritage takes place. The study of a few representative examples is tackled, focusing in the key aspects involved in the achievement of a successful project, not only respecting the surrounding conditions, but also increasing the objective and subjective value of the place.

Tesis de Maestría