Calcium transport in gill cells of Ucides cordatus, a mangrove crab living in variable salinity environments

Crustaceans show discontinuous growth and have been used as a model system for studying cellular mechanisms of calcium transport, which is the main mineral found in their exoskeleton. Ucides cordatus, a mangrove crab, is naturally exposed to fluctuations in calcium and salinity. To study calcium transport in this species during isosmotic conditions, dissociated gill cells were marked with fluo-3 and intracellular Ca2+ change was followed by adding extracellular Ca2+ as CaCl2 (0, 0.1, 0.25, 0.50, 1.0 and 5 mM), together with different inhibitors. for control gill cells, Ca2+ transport followed Michaelis-Menten kinetics with V-max = 0.137 +/- 0.001 Delta Ca(2+)i (mu M x 22.10(4) cells(-1) x 180 s(-1); N = 4; r(2) = 0.99); K-m = 0.989 +/- 0.027 mM. the use of different inhibitors for gill cells showed that amiloride (Na+/Ca2+ exchange inhibitor) inhibited 80% of Ca2+ transport in gill cells (V-max). KB-R, an inhibitor of Ca influx in vertebrates, similarly caused a decrease in Ca2+ transport and verapamil (Ca2+ channel inhibitor) had no effect on Ca2+ transport, while nifedipine (another Ca2+ channel inhibitor) caused a 20% decrease in Ca2+ affinity compared to control values. Ouabain, on the other hand, caused no change in Ca2+ transport while vanadate increased the concentration of intracellular calcium through inhibition of Ca2+ efflux probably through the plasma membrane Ca2+-ATPase. Results show that transport kinetics for Ca2+ in these crabs under isosmotic conditions is lower compared to a hyper-regulator freshwater crab Dilocarcinus pagei studied earlier using fluorescent Ca2+ probes. These kinds of studies will help understanding the comparative mechanisms underlying the evolution of Ca transport in crabs living in different environments. (C) 2013 Elsevier Inc. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo UNIFESP, Dept Renal Physiol, São Paulo, BrazilUniv São Paulo, Inst Biociencias, Dept Physiol, BR-05508900 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Renal Physiol, São Paulo, BrazilFAPESP: FAPESP 2009/15546-3Web of Scienc

Citogenética vegetal: da era clássica à molecular.

bitstream/CNPT-2010/40703/1/p-do85.pd

Nutrição é uma das bases da evolução da avicultura de corte no Brasil.

Projeto: 11.11.11.111

Viabilidade polínica como seleção assistida no programa de melhoramento genético de triticale.

201

Minimum accelerometer wear-time for reliable estimates of physical activity and sedentary behaviour of people receiving haemodialysis

From Springer Nature via Jisc Publications RouterHistory: received 2020-01-31, accepted 2020-06-01, registration 2020-06-01, online 2020-06-16, epub 2020-06-16, collection 2020-12Background: Low levels of physical activity are implicated in low life expectancies of people receiving maintenance haemodialysis. Accelerometers are increasingly being used to quantify activity behaviours of this population but guidance to quality-assure such data is lacking. The objective of this study was to provide data processing and reduction recommendations to ensure accelerometer-derived outcomes are sufficiently reliable for interpretative analysis. Methods: Seventy people receiving maintenance haemodialysis (age 55.9 ± 15.7 years, 34% women, 23% diabetic) from a single outpatient renal unit volunteered for the study. Participants wore Actigraph GT3x and ActivPAL monitors during waking hours over seven days. Reliability of accelerometer output (normalised to wear-time) was assessed via intraclass correlation coefficient (ICC). The Spearman-Brown prophecy formula was subsequently applied to the ICCs to derive the minimum required accelerometer wear-time for each behavioural outcome. Results: Monitor wear compliance was greater on dialysis compared to non-dialysis days (90% v 77%). Participants were significantly more active on non-dialysis days compared to dialysis days but there were no significant differences in estimated behaviours between days within the same condition. Average measure ICCs for all accelerometer outcomes were high (range 0.76–0.96). Computations indicated that habitual physical activity and sedentary behaviour could be estimated with a minimum reliability level of 0.80 from one dialysis day and two non-dialysis days, and at least eight hours monitor wear per day. Applying this rubric allowed 90% of participant data to be retained for further analysis. Conclusions: Regardless of accelerometer, one dialysis and two non-dialysis days data with a minimum of eight hours wear each day should enable habitual activity of people receiving maintenance haemodialysis to be characterised with acceptable reliability. These recommendations reconcile the tension between wear-time criteria stringency and retention of an adequately representative sample.21pubpu

Fatores ambientais que afetam a taxa se secagem no grão de milho (Zea mays L.) após a maturidade fisiológica.

Avaliou-se a influencia dos fatores ambientais na perda de agua pelo grao de milho (Zea mays L.), apos a maturidade fisiologica, em duas safras (1995/96 e 1997/98), em Botucatu, SP. O delineamento experimental utilizado foi o de blocos casualizados, com cinco e quatro repeticoes, nas respectivas safras. A avaliacao da perda de agua do grao, em nove cultivares (AG 122, AG 1051, AG 9012, AG 8012, C 901, XL 370, Z 8392, Z 8452 e Z 8501), iniciou-se apos todas as cultivares terem atingido a maturidade fisiologica. Posteriormente, a perda de agua pelos graos foi correlacionada com as medias dos elementos meteorologicos no periodo amostrado. Os resultados indicaram que graus-dia, radiacao solar global, insolacao e evaporacao do tanque classe A foram os elementos que mais se relacionaram com a perda de agua nos graos, com efeito quadratico e que ate aproximadamente 16% de teor de agua no grao estes fatores apresentaram efeito bem marcante