CDP

1.1. A third form (D3) of cyclic nucleotide phosphodiesterase from Rhizobiumfrediiv/as detected and characterized for the first time.2.2. The enzyme could hydrolyse both cyclic AMP and cyclic GMP with apparent Km for cyclic AMP of approx. 0.2 μM.3.3. D3 cyclic nucleotide phosphodiesterase had a pH optimum of about 6.0 when hydrolysing cyclic AMP.4.4. The enzyme lost almost all its activity when heated to 60°C for 20 min.5.5. Gel filtration with Sephadex G-100 gave a mol. wt of approx. 42.5 kD for the native enzyme.

Vanicek N, Strike S, McNaughton L, Polman R. Postural responses to dynamic perturbations in amputee fallers versus nonfallers: a comparative study with able-bodied subjects.To quantify postural responses in amputee fallers versus nonfallers by using computerized dynamic posturography.All participants completed standard protocols on the Sensory Organization Test (SOT) and Motor Control Test (MCT) of the NeuroCom Equitest.Human performance laboratory in a university in the United Kingdom.Transtibial amputees (n=9) and able-bodied subjects (n=9) (all categorized into fallers and nonfallers according to their falls history in the previous 9mo).Not applicable.Equilibrium and strategy scores on the SOT. Postural response latency and weight distribution on the MCT.Equilibrium scores were highest when somatosensory information was accurate, but there were no differences between the groups. Strategy scores were lower when visual cues and somatosensory information were inaccurate, and the fallers and nonfallers used a combination of ankle and hip strategies to prevent a loss of balance. The amputee nonfallers indicated they had a greater reliance on visual input even when it was inaccurate compared with the amputee fallers, whereas the control fallers used the hip strategy significantly more compared with the control nonfallers (SOT condition 6: 56±22 vs 72±10, P=.01). Weight distribution symmetry showed that the amputee nonfallers bore significantly more weight through their intact limb compared with the amputee fallers during backward and forward translations (P<.05).The SOT and MCT appeared to be population specific and therefore did not reliably identify fallers among transtibial amputees or distinguish between community-dwelling control fallers and nonfallers. Amputee and control fallers can prevent a fall during challenging static and dynamic conditions by adapting their neuromuscular responses. The results from this study have important implications for amputee gait rehabilitation, falls prevention, and treatment programs.

As comunidades de prática constituem um espaço privilegiado de interacção entre os seus membros, promovendo a aprendizagem e a partilha de conhecimento. Sendo esta última uma condição crítica de sucesso para a promoção da inovação, revela-se, pois, crucial, compreender os factores organizacionais que poderão condicionar esta partilha, inibindo-a ou potenciando-a. Assim, nesta comunicação começa-se por evidenciar a evolução do conceito de comunidade de prática (CdP), o seu modo de funcionamento e as suas características, dando-se algum enfoque às comunidades mediadas através de dispositivos electrónicos – as e-CdP ou comunidades digitais. Segue-se a descrição de alguns dos factores que podem condicionar a partilha de conhecimento. Apresentam-se, também, os benefícios e os inconvenientes das CdP para as organizações, bem como algumas recomendações para que estas possam usufruir do potencial relacionado com aquelas comunidades no sentido de promoverem o respectivo sucesso e a inovação.

To investigate whether and how mitochondria can change in plant programmed cell death (PCD), we used the non-photosynthetic Tobacco Bright Yellow 2 (TBY-2) cells. These can be synchronized to high levels, stand out in terms of growth rate and homogeneity and undergo PCD as a result of heat shock. Using these cells we investigated the activity of certain mitochondrial proteins that have a role in providing ATP and/or other nucleoside triphosphates (NTPs). We show that, already after 2 h from the heat shock, when cell viability remains unaffected, the rate of ADP/ATP exchange due to adenine nucleotide translocator (ANT) activity, and the rate of the reactions catalysed by adenylate kinase (ADK; EC 2.7.4.3) and nucleoside diphosphate kinase (NDPK; EC 2.7.4.6) are inhibited in a non-competitive-like manner. In all cases, externally added ascorbate partially prevented the inhibition. These effects occurred in spite of minor (for ANT) or no changes in the mitochondrial protein levels as i...