El Chato Murciano es una raza local porcina autóctona del sureste de España y en peligro de extinción. Esta raza, al igual que otras muchas razas locales, está amenazada por los efectos de la endogamia y el cruce con otras razas porcinas. En el presente trabajo se utilizaron conjuntamente tres marcadores genéticos, concretamente un panel de 34 microsatélites, un panel de alta densidad de SNPs y un fragmento de ADN mitocondrial que se analizaron en la práctica totalidad de la población de Chato Murciano. Además, se analizó el fragmento de ADN mitocondrial y el panel de SNPs en cerdos de aquellas razas que con mayor probabilidad han contribuido a la composición genética actual de la raza Chato Murciano. / Local breeds often are regarded as part of the cultural heritage of local and national communities. One of those breeds categorized as endangered on the List for Domestic Animal Diversity Information System (DAD‐IS, http://dad.fao.org/) is the Chato Murciano (CM) pig breed. The CM breed is autochthonous to the Region of Murcia (Spain). It has similar characteristics to other Spanish local breeds such as rusticity, high adaptation to the environment and low productivity compared with commercial porcine breeds.

This study is a continuation of a project to characterise ASTM A437 Grade B4B martensitic stainless steel for use In Hitachi Canadian Industries Ltds (HCI) steam turbine casing bolts. ASTM A437 Grade B4B steel is commercially available and was chosen for the study due to its chemical similarity to a proprietary steel currently used by HCI.<p>High creep resistance is essential for any candidate so creep-rupture and creep-strain tests were performed at and above the intended service temperature of 538°C. Hardness measurements and transmission electron microscopy were performed on the steel in the as-received condition as well as on crept samples to determine the effect of elevated temperature on the development of the steels microstructure.<p>During testing, it was found that ASTM A437 Grade B4B steel has a well defined second stage leading to an abrupt transition into the third stage. The second stage begins in the first 10% of its creep life, while the third stage begins at 90% of its creep life. This equates to 5% and 30% of the final strain, respectively, with an average final strain of 20%.<p>Time-to-Rupture data show good similarity to the creep life as predicted using the Larson-Miller method. When plotted, the steady-state creep rate shows a definite correlation between the creep stress and temperature. From this an empirical relationship was developed to predict the steady-state creep rate.<p> Transmission electron microscopy (TEM) results showed a significant change in the icrostructure between crept and as-received steel. Coarsening of carbides along grain boundaries most likely led to a recovery of the microstructure in the crept samples. Literature suggests that the composition of the carbides is most likely tungsten and molybdenum intermetalics and carbides that coarsened from the depletion of chromium from solution. This was supported by energy dispersive spectroscopy (EDS) analysis.<p>The coarsening of carbides correlates with the decrease in creep resistance of the material and it is likely that the growth of precipitates and recovery of the microstructure causes the entry of the steel into third stage creep.

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No description available.

Within the pig population of Northeast Scotland resistance to tetracycline and ampicillin was found to be widespread among commensal <I>Escherichia coli, </I>as also noted among anaerobic commensals of the genera <I>Bacteroides </I>and <I>Lactobacillus. E. coli </I>resistant to apramycin and nalidixic acid and enterococci resistant to vancomycin were less frequently isolated but remained common. Production system, piglet age and recent transportation were found to influence the antibiotic resistant proportion of the faecal <I>E. coli </I>population whilst dietary copper inclusion did not. Within the intestinal tract higher proportions of resistance to ampicillin were noted among the <I>E. coli </I>of the ileum and caecum than more distal sections and to apramycin and nalidixic acid among the ileal mucosal associated <I>E. coli </I>than those of the ileal lumen. Novel techniques for characterising and modelling antibiotic resistant bacterial populations were suggested and investigated. A spiral-plater system was used to investigate the phenotypic expression of antibiotic resistance among faecal <I>E. coli, </I>complemented by the development of a PCR technique to identify the genetic basis of tetracycline resistance. The effects of antimicrobial supplementation on the indigenous enteric flora were monitored through the validation and use of an <I>in vitro </I>porcine ileal simulation. Within the same model transmission of genetic material encoding antibiotic resistance was demonstrated between commensal and pathogenic representatives of the <I>Enterobacteriaceae </I>under ileal conditions. Variation in the mucosal adherence of <I>E. coli </I>expressing different antibiotic resistant attributes was investigated <I>in vitro </I>following the implementation of a modified cell culture technique.

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No description available.

Leishmania aethiopica causes two distinct forms of cutaneous leishmaniasis in the highlands of Ethiopia and in northern Kenya: the generally self-healing localised cutaneous leishmaniasis (LCL) and diffuse cutaneous leishmaniasis (DCL), which does not self-heal. Unlike other Leishmania parasites, the pathological and infectious processes associated with exposure to this parasite are not well studied in experimental systems, mainly due to the lack of a suitable in vivo model. This study was undertaken to develop an experimental model to examine the distribution and fate of parasites and pathological processes that take place after infection with L. aethiopica. It was also the aim of this work to develop a diagnostic system to directly identify parasites in potentially infected tissue with or without the presence of clinical signs of disease. Several laboratory animals including 12 strains of mice from a spectrum of genetic backgrounds, two strains of hamsters and other experimental animals such as rabbits, guinea pigs, gerbils and cotton rats were tested. All animals were inoculated with late stationary phase culture promastigotes of L. aethiopica and examined over a period of 18 months. Evaluation of the outcome of infection was monitored by observing the production of lesions and isolating cultivable parasites from sites of inoculation. The fate and distribution of parasites was investigated using culture, histology and PCR to identify L. aethiopica-specific DNA. The results revealed differences in susceptibility to L. aethiopica infection within the strains of mice used. Cultivable parasites were isolated from the footpads of BALB/c, BALB/c nude and CBA nude mice up to 16 days post infection whereas SCID mice retained live parasites for a longer period of 20 days. CBA and C57/BL mice cleared cultivable parasites from sites of inoculation within 8 and 12 days respectively. Overall, BALB/c mice retained detectable parasite DNA for the longest period (550 days) post-infection in the footpads, draining lymph nodes and the liver. Among mice with intact genetic backgrounds, only BALB/c mice showed cellular in vivo responses at the site of parasite inoculation that peaked at day 13. Hamsters were found to be the only animals that produced clinical lesions (46%). In addition, live parasites were isolated from the site of inoculation (55%) and from the draining lymph nodes (50%) after 390 days post-infection. L aethiopica kinetoplast DNA was detected up to 470 days post infection in 82% of noses and 91% of draining lymph nodes. Hamsters exhibited the ability to retain cultivable parasites late in the course of infection regardless of the presence or absence of lesions. These results indicate that hamsters are potentially suitable models to study the fate and distribution of L. aethiopica. The detection of parasites using the amplified DNA signatures was found to be superior to conventional methods such as histology and culture in that it was sensitive, specific and simple. The PCR method that was developed during this work involved extraction of nucleic acids from cultured parasites, tissues and smears, amplifying L. aethiopica-specific DNA using a universal primer for a conserved Leishmania kinetoplast sequence together with an L. aethiopicaspecific oligonucleotide. The amplified fragments were 864bp in length and were initially characterised by restriction digest analysis using Hae HI restriction enzyme digestion as a result of which several patterns were recognised. To confirm this diversity in k-DNA sequences, amplified fragments were cloned using pCRII® TA cloning kit and the recombinant clones were digested to confirm the patterns observed initially and were sequenced. The sequences that were generated were analysed using the BLAST alignment facility of the National Centre for Biotechnology Information (NCBI). All fragments were Leishmania kinetoplast in origin but were found to possess varying percentages of similarity ranging from 50% to 100% among themselves. Analysis of these results suggested that L. aethiopica isolates that originated from individual patients possess genetic differences in their k-DNA sequences. In summary, the results generated from this work indicate that the hamster is a suitable model for studying cutaneous leishmaniasis caused by L. aethiopica and that both hamsters and mice can be used to study parasite distribution in experimental leishmaniasis. It was also revealed that there are genetic differences within the kinetoplast of L. aethiopica isolates. These genetic differences within L. aethiopica DNA could be exploited to better understand the diversity within the causative agent of Ethiopian Cutaneous Leishmaniasis.

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No description available.