Aerobic and Anaerobic Swimming Force Evaluation in One Single Test Session for Young Swimmers

This study aims to propose and validate the tethered swimming lactate minimum test (TSLacmin) estimating aerobic and anaerobic capacity in one single test session, using force as measurement parameter. 6 male and 6 female young swimmers (age=15.7±1.1 years; height=173.3±9.5 cm; weight=66.1±9.5 kg) performed 4 sessions comprising i) an all-out 30 s test and incremental test (TSLacmin); ii) 30 min of tethered swimming at constant intensity (2 sessions); iii) free-swimming time trials used to calculate critical velocity. Tethered swimming sessions used an acquisition system enabling maximum (Fmax) and mean (Fmean) force measurement and intensity variation. The tethered all-out test lasting 30 s resulted in hyperlactatemia of 7.9±2.0 mmol·l^-1. TSLacmin presented a 100% success applicability rate, which is equivalent to aerobic capacity in 75% of cases. TSLacmin intensity was 37.7±7.3 N, while maximum force in the all-out test was 105±27 N. Aerobic and anaerobic TSLacmin parameters were significantly related to free-swimming performance (r=-0.67 for 100 m and r=-0.80 for 200 m) and critical velocity (r=0.80). TSLacmin estimates aerobic capacity in most cases, and both aerobic and anaerobic force parameters are well related to critical velocity and free swimming performance.

Lactate minimum underestimates the maximal lactate steady-state in swimming mice

The intensity of lactate minimum (LM) has presented a good estimate of the intensity of maximal lactate steady-state (MLSS); however, this relationship has not yet been verified in the mouse model. We proposed validating the LM protocol for swimming mice by investigating the relationship among intensities of LM and MLSS as well as differences between sexes, in terms of aerobic capacity. Nineteen mice (male: 10, female: 9) were submitted to the evaluation protocols for LM and MLSS. The LM protocol consisted of hyperlactatemia induction (30 s exercise (13% body mass (bm)), 30 s resting pause and exhaustive exercise (13% bm), 9 min resting pause and incremental test). The LM underestimated MLSS (mice: 17.6%; male: 13.5%; female: 21.6%). Pearson's analysis showed a strong correlation among intensities of MLSS and LM (male (r = 0.67, p = 0.033); female (r = 0.86, p = 0.003)), but without agreement between protocols. The Bland-Altman analysis showed that bias was higher for females (1.5 (0.98) % bm; mean (MLSS and LM): 4.4%-6.4% bm) as compared with males (0.84 (1.24) % bm; mean (MLSS and LM): 4.5%-7.5% bm). The error associated with the estimated of intensity for males was lower when compared with the range of means for MLSS and LM. Therefore, the LM test could be used to determine individual aerobic intensity for males (considering the bias) but not females. Furthermore, the females supported higher intensities than the males. The differences in body mass between sexes could not explain the higher intensities supported by the females.

Update of the gene discovery program in Schistosoma mansoni with the expressed sequence tag approach

Continuing the Schistosoma mansoni Genome Project 363 new templates were sequenced generating 205 more ESTs corresponding to 91 genes. Seventy four of these genes (81%) had not previously been described in S. mansoni. Among the newly discovered genes there are several of significant biological interest such as synaptophysin, NIFs-like and rho-GDP dissociation inhibitor.

Evaluation of cDNA libraries from different developmental stages of Schistosoma mansoni for production of expressed sequence tags (ESTs)

A comparative study of the gene expression profile in different developmental stages of Schistosoma mansoni has been initiated based on the expressed sequence tag (EST) approach. A total of 1401 ESTs were generated from seven different cDNA libraries constructed from four distinct stages of the parasite life cycle. The libraries were first evaluated for their quality for a large-scale cDNA sequencing program. Most of them were shown to have less than 20% useless clones and more than 50% new genes. The redundancy of each library was also analyzed, showing that one adult worm cDNA library was composed of a small number of highly frequent genes. When comparing ESTs from distinct libraries, we could detect that most genes were present only in a single library, but others were expressed in more than one developmental stage and may represent housekeeping genes in the parasite. When considering only once the genes present in more than one library, a total of 466 unique genes were obtained, corresponding to 427 new S. mansoni genes. From the total of unique genes, 20.2% were identified based on homology with genes from other organisms, 8.3% matched S. mansoni characterized genes and 71.5% represent unknown genes.