Polymorphism and physiology of arsenate tolerance in Holcus lanatus L. from an uncontaminated site

<p>The polymorphism of arsenate tolerance in a Holcus lanatus L. population from an uncontaminated soil was investigated and a high percentage of tolerant individuals (65%) was found in the population studied. Influx of arsenate was highly correlated to arsenate tolerance within the population, with the most tolerant individuals having the lowest rates of arsenate influx. Isotherms for the high affinity arsenate uptake systems were determined in six tolerant and six non-tolerant genotypes. Tolerant plants had the lowest rates of arsenate influx. This was achieved by adaptation of the V_max of arsenate influx with the V_max of the high affinity uptake system saturating at lower substrate concentrations in the tolerant plants. The polymorphism is discussed with relation to adaptation to the extreme environments to which the plants are subjected on mine-spoil soils. �� 1992 Kluwer Academic Publishers.</p>

STI-571 (imatinib mesylate) enhances the apoptotic efficacy of pyrrolo-1,5-benzoxazepine-6, a novel microtubule-targeting agent, in both STI-571-sensitive and -resistant Bcr-Abl-positive human chronic myeloid leukemia cells

<p>Interactions between the Bcr-Abl kinase inhibitor STI-571 (imatinib mesylate) and a novel microtubule-targeting agent (MTA), pyrrolo-1,5-benzoxazepine (PBOX)-6, were investigated in STI-571-sensitive and -resistant human chronic myeloid leukemia (CML) cells. Cotreatment of PBOX-6 with STI-571 induced significantly more apoptosis in Bcr-Abl-positive CML cell lines (K562 and LAMA-84) than either drug alone (P &lt; 0.01). Cell cycle analysis of propidium iodide-stained cells showed that STI-571 significantly reduced PBOX-6-induced G2M arrest and polyploid formation with a concomitant increase in apoptosis. Similar results were obtained in K562 CML cells using lead MTAs (paclitaxel and nocodazole) in combination with STI-571. Potentiation of PBOX-6-induced apoptosis by STI-571 was specific to Bcr-Abl-positive leukemia cells with no cytoxic effects observed on normal peripheral blood cells. The combined treatment of STI-571 and PBOX-6 was associated with the down-regulation of Bcr-Abl and repression of proteins involved in Bcr-Abl transformation, namely the antiapoptotic proteins Bcl-x(L) and Mcl-1. Importantly, PBOX-6/STI-571 combinations were also effective in STI-571-resistant cells. Together, these findings highlight the potential clinical benefits in simultaneously targeting the microtubules and the Bcr-Abl oncoprotein in STI-571-sensitive and -resistant CML cells.</p>

Effect of water chemistry on the physiology and toxicity assessment in Daphnia

Todos os sistemas aqu��ticos est��o potencialmente expostos a altera����es nos par��metros da ��gua em consequ��ncia de fen��menos ambientais tais como deposi����o ��cida, lixivia����o de i��es dos solos e altera����es clim��ticas. Dado que os par��metros qu��micos da ��gua est��o geralmente correlacionados, �� pertinente estudar os seus efeitos combinados para o biota aqu��tico. Assim, o principal objetivo desta tese �� avaliar a import��ncia ecol��gica da varia����o simult��nea dos principais par��metros fisico-qu��micos da ��gua nos par��metros de hist��ria de vida dos crust��ceos tanto na aus��ncia como na presen��a de metais. Foram estudados os seguintes par��metros: dureza (0.5 - 3.5 mM), alcalinidade (0.3 - 2.3 mM), pH (5.7 - 9.0) e temperatura (13 - 30��C). A Daphnia magna foi usada como esp��cie modelo representando os crust��ceos aqu��ticos. A varia����o simult��nea da dureza e alcalinidade afetou significativamente o crescimento, reprodu����o e crescimento populacional de Daphnia; no entanto, os efeitos da dureza excederam os efeitos da alcalinidade. Pareceu haver intera����o entre a dureza e alcalinidade na reprodu����o dos dafn��deos, o que sugere que os efeitos da varia����o da dureza para Daphnia e provavelmente outros crust��ceos poder��o depender do n��vel de alcalinidade. O pH e dureza da ��gua exerceram efeitos combinados para Daphnia, sendo os efeitos do pH mais pronunciados do que os efeitos da dureza. A diminui����o do pH reduziu a sobreviv��ncia, crescimento, reprodu����o, taxa de ingest��o e crescimento populacional dos dafn��deos. No entanto, os efeitos do pH baixo foram mais adversos a baixa dureza, o que sugere uma intera����o entre estes par��metros. Assim, a diminui����o do pH em lagos de ��gua mole pode ser um estressor determinante para os crust��ceos sens��veis �� acidez, amea��ando a sua sobreviv��ncia e, consequentemente, afetando a estrutura das cadeias alimentares aqu��ticas. A temperatura e a qu��mica da ��gua (dureza e alcalinidade) interagiram entre si nos par��metros de hist��ria de vida de Daphnia; no entanto, os efeitos da temperatura excederam os efeitos da qu��mica da ��gua. De um modo geral, temperaturas extremas reduziram o crescimento, reprodu����o e, consequentemente, o crescimento populacional de Daphnia. Os efeitos do aumento da temperatura foram mais adversos a baixa dureza e alcalinidade, aumentando a preocupa����o com os efeitos ecol��gicos do aquecimento global em ��guas moles. A dureza e alcalinidade da ��gua tamb��m desempenharam um papel importante na toxicidade aguda e subletal (inibi����o da ingest��o) dos metais para Daphnia. A diminui����o da dureza aumentou a toxicidade aguda do zinco. Por outro lado, a diminui����o da alcalinidade aumentou a toxicidade aguda e subletal do cobre, mas reduziu a toxicidade subletal do zinco, tornando evidente o importante papel da alcalinidade na toxicidade subletal dos metais para Daphnia. Globalmente, os par��metros fisico-qu��micos da ��gua parecem interagir entre si, afetando os par��metros de hist��ria de vida e o crescimento populacional de Daphnia e tamb��m afetam a toxicidade dos metais. Em particular, a baixa dureza agrava os efeitos adversos da diminui����o do pH, aumento da temperatura e toxicidade dos metais, o que aumenta a preocupa����o com os efeitos ecol��gicos da sua varia����o simult��nea sobre os crust��ceos e, portanto, sobre as cadeias alimentares aqu��ticas.

Physiology and metabolic profile of Moringa olifera and Eucalyptus globulus plants subjected to climate changes

As altera����es clim��ticas emergentes t��m um grande impacto no crescimento e desenvolvimento de esp��cies florestais, nomeadamente em esp��cies de valor industrial e medicinal, como �� o caso do eucalipto (Eucalyptus globulus) e da moringa (Moringa oleifera). Assim, �� urgente conhecer as respostas fisiol��gicas e entender as varia����es que ocorrem nos perfis metab��licos de esp��cies vegetais. Neste trabalho, plantas jovens de Eucalyptus globulus foram expostas a radia����o UVB (12kJ/m2) e foram avaliadas as respostas fisiol��gicas e o perfil metab��lico, um e onze dias ap��s a aplica����o da radia����o. A dose de UVB usada n��o afetou as rea����es fotoqu��micas nem as trocas gasosas, contudo ao n��vel do metabolismo do carbono (AST e amido) e do conte��do de pigmentos verificaram-se pequenas altera����es (AST e pigmentos). Atrav��s da an��lise do perfil metab��lico de E. globulus foram encontrados compostos vol��teis e semi-vol��teis pertencentes ��s fam��lias dos terpenos, sesquiterpenos e alde��dos. Em geral, os sesquiterpenos e os ��lcoois monoterp��nicos apresentaram uma tend��ncia para manter e, em alguns casos, diminuir com o stress, enquanto que o grupos dos alde��dos aumentou e os monoterpenos apresentaram um comportamento mais heterog��neo. O E. globulus mostrou ser uma esp��cie tolerante �� aplica����o da dose de UVB usada neste trabalho. Por outro lado, plantas jovens de M. oleifera foram expostas a d��fice h��drico (DH). Um grupo de plantas foi recolhido um dia ap��s o final da exposi����o e o outro grupo ap��s onze dias do final da exposi����o. Foi avaliado o perfil metab��lico desta esp��cie atrav��s de GC/MS. Os dados cromatogr��ficos indicaram que em condi����es de stress (DH(1) e DH(11)), as quantidades de compostos associados a vias prim��rias e secund��rias de defesa (como os alcanos, ��lcoois, ��cidos carbox��licos, ester��is, amino��cidos e a��ucares) sofreram algumas altera����es. As plantas analisadas 11 dias ap��s a remo����o do stress mostraram maiores varia����es do perfil de metabolitos. No entanto, tanto um como onze dias ap��s a remo����o do stress, as plantas apresentaram a forma����o de novos rebentos. Apesar do perfil de metabolitos ter sofrido algumas altera����es, por n��o se registarem casos de morte, conclui-se que as plantas de moringa mostraram ser tolerantes aos tratamentos aplicados.

Impact of multi-metals (Cd, Pb and Zn) exposure on the physiology of the yeast Pichia kudriavzevii

Metal contamination of the environment is frequently associated to the presence of two or more metals. This work aimed to study the impact of a mixture of metals (Cd, Pb and Zn) on the physiology of the non-conventional yeast Pichia kudriavzevii. The incubation of yeast cells with 5 mg/l Cd, 10 mg/l Pb and 5 mg/l Zn, for 6 h, induced a loss of metabolic activity (assessed by FUN-1 staining) and proliferation capacity (evaluated by a clonogenic assay), with a small loss of membrane integrity (measured by trypan blue exclusion assay). The staining of yeast cells with calcofluor white revealed that no modification of chitin deposition pattern occurred during the exposure to metal mixture. Extending for 24 h, the exposure of yeast cells to metal mixture provoked a loss of membrane integrity, which was accompanied by the leakage of intracellular components. A marked loss of the metabolic activity and the loss of proliferation capacity were also observed. The analysis of the impact of a single metal has shown that, under the conditions studied, Pb was the metal responsible for the toxic effect observed in the metal mixture. Intracellular accumulation of Pb seems to be correlated with the metals' toxic effects observed.

Modulation of electrical stimulation applied to human physiology and clinical diagnostic

The use, manipulation and application of electrical currents, as a controlled interference mechanism in the human body system, is currently a strong source of motivation to researchers in areas such as clinical, sports, neuroscience, amongst others. In electrical stimulation (ES), the current applied to tissue is traditionally controlled concerning stimulation amplitude, frequency and pulse-width. The main drawbacks of the transcutaneous ES are the rapid fatigue induction and the high discomfort induced by the non-selective activation of nervous fibers. There are, however, electrophysiological parameters whose response, like the response to different stimulation waveforms, polarity or a personalized charge control, is still unknown. The study of the following questions is of great importance: What is the physiological effect of the electric pulse parametrization concerning charge, waveform and polarity? Does the effect change with the clinical condition of the subjects? The parametrization influence on muscle recruitment can retard fatigue onset? Can parametrization enable fiber selectivity, optimizing the motor fibers recruitment rather than the nervous fibers, reducing contraction discomfort? Current hardware solutions lack flexibility at the level of stimulation control and physiological response assessment. To answer these questions, a miniaturized, portable and wireless controlled device with ES functions and full integration with a generic biosignals acquisition platform has been created. Hardware was also developed to provide complete freedom for controlling the applied current with respect to the waveform, polarity, frequency, amplitude, pulse-width and duration. The impact of the methodologies developed is successfully applied and evaluated in the contexts of fundamental electrophysiology, psycho-motor rehabilitation and neuromuscular disorders diagnosis. This PhD project was carried out in the Physics Department of Faculty of Sciences and Technology (FCT-UNL), in straight collaboration with PLUX - Wireless Biosignals S.A. company and co-funded by the Foundation for Science and Technology.

The physiology of inscription : Foucault's genealogy as curative science

In ''Nietzsche, Genealogy, History," Foucault suggests that genealogy is a sort of "curative science." The genealogist must be a physiologist and a pathologist as well as an historian, for his task is to decipher the marks that power relations and historical events leave on the subjugated body; "he must be able to diagnose the illnesses of the body, its conditions of weakness and strength, its breakdowns and resistances, to be in a position to judge philosophical discourse." But this claim seems to be incongruent with another major task of genealogy. After all, genealogy is supposed to show us that the things we take to be absolute are in fact discontinuous and historically situated: "Nothing in man-not even his body-is sufficiently stable to serve as the basis for self-recognition or for understanding other men." If this is true, then the subjugated body can never be restored to a healthy state because it has no essential or original nature. There are no universal standards by which we can even distinguish between healthy and unhealthy bodies. So in what sense is genealogy to be a "curative science"? In my thesis, I try to elucidate the complex relationship between genealogy and the body. I argue that genealogy can be a curative science even while it "multiplies our body and sets it against itself." Ifwe place a special emphasis on the role that transgression plays in Foucault's genealogical works, then the healthy body is precisely the body that resists universal standards and classifications. If genealogy is to be a curative science, then it must restore to the subjugated body an "identity" that transgresses its own limits and that constitutes itself, paradoxically, in the very effacement of identity. In the first chapter of my thesis, I examine the body's role as "surface of the inscription of events." Power relations inscribe on and around the body an identity or subjectivity that appears to be unified and universal, but which is in fact disparate and historically situated. The "subjected" body is the sick and pathologically weak body. In Chapters 2 and 3, I describe how it is possible for the unhealthy body to become healthy by resisting the subjectivity that has been inscribed upon it. Chapter 4 explains how Foucault's later works fit into this characterization of genealogy

The earliest days of the teetotal movement: dialogues on drink and physiology for the young (1900)

Contents extracted from "Upward", the monthly magazine of the Preston Board of Hope Union, July 1897-January 1899 and June 1900, and from "The Temperance Mirror", February 1900, one of 20 copies. Inscribed on "Explanatory" page: Wm. Livesey. August 3rd 1900. Inscribed on title-page: J. Sherlock, with W. Livesey's Kind Regards.

Canadian Society for Exercise Physiology Position Paper: Resistance Training in Children and Adolescents

Many position stands and review papers have refuted the myths associated with resistance training (RT) in children and adolescents. With proper training methods, RT for children and adolescents can be relatively safe and improve overall health. The objective of this position paper and review is to highlight research and provide recommendations in aspects of RT that have not been extensively reported in the pediatric literature. In addition to the well-documented increases in muscular strength and endurance, RT has been used to improve function in pediatric patients with cystic fibrosis, cerebral palsy and burn victims. Increases in children���s muscular strength have been attributed primarily to neurological adaptations due to the disproportionately higher increase in muscle strength than in muscle size. Although most studies using anthropometric measures have not shown significant muscle hypertrophy in children, more sensitive measures such as magnetic resonance imaging and ultrasound have suggested hypertrophy may occur. There is no minimum age for RT for children. However the training and instruction must be appropriate for children and adolescents involving a proper warm-up, cool-down and an appropriate choice of exercises. It is recommended that low-to-moderate intensity resistance should be utilized 2-3 times per week on non-consecutive days, with 1-2 sets initially, progressing to 4 sets of 8-15 repetitions for 8-12 exercises. These exercises can include more advanced movements such as Olympic style lifting, plyometrics and balance training, which can enhance strength, power, co-ordination and balance. However specific guidelines for these more advanced techniques need to be established for youth. In conclusion, a RT program that is within a child���s or adolescent���s capacity, involves gradual progression under qualified instruction and supervision with appropriately sized equipment can involve more advanced or intense RT exercises which can lead to functional (i.e. muscular strength, endurance, power, balance and co-ordination) and health benefits.