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Assimilação por bactérias do carbono e nitrogênio provenientes da matéria orgânica excretada e celular de Planktothrix agardhii
(Universidade Federal de São Carlos, 2010-05-26) Tessarolli, Letícia Piton; Vieira, Armando Augusto Henriques; https://lattes.cnpq.br/4428377384377272; https://lattes.cnpq.br/4024406734152899
The cyanobacterium Planktothrix agardhii is an important organism for the dynamics of Barra Bonita reservoir due to recurrent blooms throughout the year. However, there are still few published data on the dynamics of polysaccharides degradation and nitrogenous compounds excreted by the cells, as well as the way this process, and the compounds available, may affect the diversity and abundance of the bacterial community. This study aimed, therefore, to determine the feasibility of the released organic matter and cell biomass of cyanobacteria as the sole source of carbon and nitrogen for bacteria. Two similar experiments were performed: one using the dissolved organic matter (DOM) released by P. agardhii as a substrate for the establishment of a community from an inoculum from Barra Bonita reservoir and the second using cellular biomass of cyanobacteria as a substrate. Analysis of carbon and nitrogen, dissolved and particulate, provided the adjustment of a decay kinetic model, while counting and analysis of bacterial morphotypes, along with Denaturing Gradient Gel Electrophoresis (DGGE), were used to establish a possible process of bacterial succession by using these substrates. The settings in the kinetic model showed two phases of degradation for both nitrogen and organic carbon: first, a rapid phase, during the first three days of degradation, followed by a slower phase of degradation. The degradation coefficients of the first phase (kT) reached values up to 60x higher than those determined for the second phase of mineralization (k3). Our values for residual compounds are in agreement with published data on the reservoir, and may have ecological implications for the possibility of export to downstream areas. Bacterial concentrations in number and total biovolume of the samples provided a curve with a peak in the second and third days of experimental culture, followed by a decline, more pronounced in curves of biovolume due to the continuing reduction in the average value per bacterial cell found in cultures. The analysis of morphotypes showed no significant differences through time in cultures with DOM, however, in cultures with bacterial biomass, a reduction in the concentration of bacilli may be observed, with a consequent increase in the concentration of coccobacilli and cocci. A preliminary analysis of the DGGE showed changes in patterns of bands produced between days 1, 3 and 5 in both experiments, which may be indicative of a succession process in these cultures. The use of these sources of carbon and nitrogen by bacteria proved therefore feasible to maintain the bacterial community and a possible succession process has been suggested.
Análises espectral e simbólica da modulação autonômica cardíaca em repouso e em resposta à mudança postural de idosos saudáveis: comparação entre gêneros
(Universidade Federal de São Carlos, 2010-05-26) Perseguini, Natália Maria; Catai, Aparecida Maria; https://lattes.cnpq.br/5801652590531684; https://lattes.cnpq.br/4760699117769332
The dissertation consisted of two works. The objective of the first study was to use linear and non-linear methods to investigate the cardiac autonomic modulation in elderly men and women in response to a postural change from the supine to the standing position. Fourteen men (66 ± 3.5 years) and ten women (65 ± 3.3 years) who did not use hormonal replacement therapy (HRT) were evaluated. All volunteers were apparently healthy. The RR intervals (RRi) and the beat-to-beat heart rate (HR) were recorded in the supine and standing positions. The HR variability (HRV) was studied by spectral analysis: low frequency (LF) and high frequency (HF) in absolute units (LF and HF) and normalized units (LFun and HFun) as well as the low frequency/high frequency (LF/HF) ratio. Symbolic analysis (0V%, 1V%, 2LV% and 2ULV% indexes) and Shannon entropy were also calculated for the HRV analysis. Men presented higher LF, LFnu and LF/HF ratio, and lower HFnu and 1V% symbolic index when compared to women in the supine position. Shannon entropy was higher among men than among women in the standing position. During the postural change there were a decrease in LF and an increase in Shannon entropy in the men s group. There was an increase in LFnu and LH/HF ratio as well as a decrease in HF, HFnu and 2LV% symbolic index due to the postural change from supine to standing position in the women s group. In conclusion, women presented a more appropriate response to the postural change than men in the age range studied, showing that the cardiac autonomic modulation may be better preserved in women than in men. Similarly, the objective of the second study was to investigate the HR autonomic modulation in elderly men and women HRT users and no-users by linear and nonlinear methods. So, 15 men (66 ± 3.4 years), 13 women without HRT (64 ± 3.5 years) and 7 women HRT users (61 ± 2.1 years), all of them apparently healthy, were evaluated. The RRi and the beat-to-beat HR were recorded in the supine position. The data analysis was carried out on the same methods described in the first study. The cardiac autonomic modulation analysis in the supine position shows that the women without HRT presented higher HFnu and lower LFnu, LF/HF ratio and 0V% symbolic index when compared to the men. No differences were observed in the comparison between the women who used and did not use HRT. We concluded that the women without HRT seem to have a higher cardiac vagal modulation and a lower cardiac sympathetic modulation when compared to the men. The use of HRT may not offer advantages to the cardiac autonomic modulation in elderly women.