Characterization of the genetic diversity of <Emphasis Type="Italic">Mycobacterium tuberculosis</Emphasis> in São Paulo city,Brazil

Background

Tuberculosis is a major health problem in São Paulo, Brazil, which is the most populous and one of the most cosmopolitan cities in South America. To characterize the genetic diversity of Mycobacterium tuberculosis in the population of this city, the genotyping techniques of spoligotyping and MIRU were applied to 93 isolates collected in two consecutive years from 93 different tuberculosis patients residing in São Paulo city and attending the Clemente Ferreira Institute (the reference clinic for the treatment of tuberculosis).

Findings

Spoligotyping generated 53 different spoligotype patterns. Fifty-one isolates (54.8%) were grouped into 13 spoligotyping clusters. Seventy- two strains (77.4%) showed spoligotypes described in the international databases (SpolDB4, SITVIT), and 21 (22.6%) showed unidentified patterns. The most frequent spoligotype families were Latin American Mediterranean (LAM) (26 isolates), followed by the T family (24 isolates) and Haarlem (H) (11 isolates), which together accounted for 65.4% of all the isolates. These three families represent the major genotypes found in Africa, Central America, South America and Europe. Six Spoligo-International-types (designated SITs by the database) comprised 51.8% (37/72) of all the identified spoligotypes (SIT53, SIT50, SIT42, SIT60, SIT17 and SIT1). Other SITs found in this study indicated the great genetic diversity of M. tuberculosis, reflecting the remarkable ethnic diversity of São Paulo city inhabitants. The MIRU technique was more discriminatory and did not identify any genetic clusters with 100% similarity among the 93 isolates. The allelic analysis showed that MIRU loci 26, 40, 23 and 10 were the most discriminatory. When MIRU and spoligotyping techniques were combined, all isolates grouped in the 13 spoligotyping clusters were separated.

Conclusions

Our data indicated the genomic stability of over 50% of spoligotypes identified in São Paulo and the great genetic diversity of M. tuberculosis isolates in the remaining SITs, reflecting the large ethnic mix of the São Paulo city inhabitants. The results also indicated that in this city, M. tuberculosis isolates acquired drug resistance independently of genotype and that resistance was more dependent on the selective pressure of treatment failure and the environmental circumstances of patients.

     

Circadian physiological rhythms

Mammals show numerous circadian rhythms, some exogenous but nonetheless useful, some endogenous. Even in the absence of exogenous synchronizers, different physiological functions usually preserve their normal temporal relations, suggesting that a single clock controls most or all of the rhythmic manifestations. The role of adrenal corticosteroids and of temperature as means whereby the clock influences other functions is considered.     

Direct Estimation of Early Survival and Movements in Eastern Wolf Pups

Abstract: Determining juvenile survival and recruitment rates is essential to assess status and viability of animal populations. Currently, the demographic attributes of juvenile carnivores, specifically wolves (Canis lycaon), are poorly known but of considerable conservation interest. We measured survival and dispersal rates for 51 juvenile (age 3.5–31 weeks) wolves in Algonquin Provincial Park, Canada, from 2004 to 2005, using implantable very high frequency transmitters. Monthly pup survival was high (0.970, 95% CI = 0.951–0.990) and constant from June to November, and most pup mortality was from natural causes. Pups dispersed as early as age 15 weeks, and monthly dispersal rates were high for young pups (min. = 0.008, 95% CI = 0.000–0.019; max. = 0.030, 95% CI = 0.010–0.050). We failed to detect any influence of pack or litter size on pup survival or probability of dispersal. Radiotelemetry offers an individual-based monitoring technique capable of providing direct assessment of wolf pup survival and movements, with rigorous estimation of survival and dispersal rates and quantification of cause-specific mortality.     

Spatio‐temporal feeding selection of red deer in a mountainous landscape

Understanding the dietary consumption and selection of wild populations of generalist herbivores is hampered by the complex array of factors. Here, we determine the influence of habitat, season, and animal density, sex, and age on the diet consumption and selection of 426 red deer (Cervus elaphus scoticus) culled in Fiordland National Park, New Zealand. Our site differs from studies elsewhere both in habitat (evergreen angiosperm‐dominated forests) and the intensity of hunting pressures. We predicted that deer would not consume forage in proportion to its relative availability, and that dietary consumption would change among and within years in response to hunting pressures that would also limit opportunities for age and sex segregation. Using canonical correspondence analysis, we evaluated the relative importance of different drivers of variation in diet consumption assessed from gut content and related these to available forage in the environment. We found that altitude explained the largest proportion of variation in diet consumption, reflecting the ability of deer to alter their consumption and selection in relation to their foraging grounds. Grasses formed a high proportion of the diet consumption, even for deer culled several kilometres from the alpine grasslands. In the winter months, when the alpine grasslands were largely inaccessible, less grass was eaten and deer resorted to woody plants that were avoided in the summer months. Surprisingly, there were no significant dietary differences between adults and juveniles and only subtle differences between the sexes. Sex‐based differences in diet consumption are commonly observed in ungulate species and we suggest that they may have been reduced in our study area owing to decreased heterogeneity in available forage as the diversity of palatable species decreased under high deer browsing pressures, or by intense hunting pressure.