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| Mairet, Francis. |
| Homeostasis is the capacity of living organisms to keep internal conditions regulated at a constant level, despite environmental fluctuations. Integral feedback control is known to play a key role in this behaviour. Here, I show that a feedback system involving transcriptional and post-translational regulations of the same executor protein acts as a proportional integral (PI) controller, leading to enhanced transient performances in comparison with a classical integral loop. Such a biomolecular controller-which I call a level and activity-PI controller (LA-PI)-is involved in the regulation of ammonium uptake by Escherichia coli through the transporter AmtB. The P-II molecules, which reflect the nitrogen status of the cell, inhibit both the production of... |
| Tipo: Text |
Palavras-chave: Homeostasis; Perfect adaptation; Regulatory motif; Transcriptional and post-translational regulations. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00434/54598/55968.pdf |
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| Günther,Bruno; Morgado,Enrique. |
| A wide spectrum of cyclic functions in terrestrial mammals of different size, from the 3-gram shrew to the 3-ton elephant, yields an allometric exponent around 0.25, which is correlated _ as a kind of common denominator _ with the specific metabolic rate. Furthermore, the applicability of these empirical findings could be extrapolated to chronological events in the sub-cellular realm. On the other hand, the succession of growth periods (T98%) until sexual maturity is reached also follows the 1/4 power rule. By means of Verhulst's logistic equation, it has been possible to simulate three different biological conditions, which means that by modifying the numerical value of only one parameter, revertible physiological and pathological states can be obtained,... |
| Tipo: Journal article |
Palavras-chave: Growth; Dimensional analysis; Specific metabolic rate; Logistic equation; Homeostasis. |
| Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602005000200010 |
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| Matos, Marize Bastos de; UENF; Ferreira, Rony Antonio; UNIVALE; Savaris, Vaneila Daniele Lenhardt; UENF; Couto, Humberto Pena; UENF; Soares, Rita da Trindade Ribeiro Nobre; UENF; Oliveira, Newton Tavares Escocard de; UENF. |
| Um experimento foi conduzido, objetivando-se avaliar o efeito do balanço eletrolítico (BER) e a redução da proteína bruta (PB) da ração sobre a frequência respiratória, temperatura cloacal, concentrações de Na+, K+, Cl- e ácido úrico em frangos de corte. Foram utilizados 800 pintos de corte, machos da linhagem Cobb, alojados em 20 boxes, distribuídos em delineamento inteiramente casualizado com quatro tratamentos, cinco repetições e 40 aves por unidade experimental. Os tratamentos foram: T1 - ração basal; T2 - ração corrigida para BER de 250 mEq kg-1; T3 - ração com redução de PB, sem correção de BER; T4 - ração com redução de PB corrigida para BER de 250 mEq kg-1. As condições ambientais evidenciaram que os animais estavam em estresse por calor. As aves... |
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Palavras-chave: 5.04.05.00-4 eletrólitos; Sangue; Homeostase; Estresse Ciencias Agrárias electrolytes; Homeostasis; Blood; Stress. |
| Ano: 2009 |
URL: http://periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/4792 |
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| Ng,Di-Lin; Tie,Shin-Wei; Ong,Pei-Chin; Lim,Wyi-Sian; Tengku-Muhammad,Tengku-Sifzizul; Choo,Quok-Cheong; Chew,Choy-Hoong. |
| The Liver X Receptor (LXR) and Pregnane X Receptor (PXR) are members of the nuclear receptor superfamily. Previously, they have been classified as important regulators of lipid homeostasis. However, recent studies have shown that they may be implicated in anti-inflammatory responses as well. This study shows that Tumour Necrosis Factor-α (TNF-α) treatment reduces both LXR-α and PXR mRNA expression. However, pre-treatment with rapamycin, an mTOR inhibitor, followed by TNF-α stimulation, significantly induces LXR-α and PXR mRNA expression to ~17- and ~2-fold, respectively. This suggests that mTORC1, a multi-molecular complex of which mTOR is a member, may act as a negative regulator that inhibits the induction of LXR-α and PXR as anti-inflammatory... |
| Tipo: Journal article |
Palavras-chave: Akt; C-Jun; Homeostasis; Inflammation; MKK7; Transcription factor. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582011000300008 |
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| Lipps,B. V.. |
| Adenosine deaminase (ADA), histamine, and IgE are endogenously present in animals. Research from this laboratory reported decreased levels of these substances in organs of mice as a consequence of sub-lethal injection of Naja kaouthia venom. This research reports that decreased ADA, histamine, and IgE levels were prevented by specific treatment and prolonged recovery periods. Adult Balb/c mice injected IM with sub-lethal venom dose were divided into five groups. Group 1 were injected with PBS; Group 2 with anti-cobra venom; and Group 3 with lethal toxin neutralizing factor (LTNF). Groups 4 and 5 were treated with IM or oral synthetic LT-10. After 24 hours, mice were sacrificed and organ homogenates were assayed for ADA, histamine, and IgE. Group 1 showed... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cobra venom; Mouse organs; ADA; Histamine; IgE; Homeostasis. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1678-91992003000200007 |
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| NUÑEZ,MARCO T; GARATE,MARCO A; ARREDONDO,MIGUEL; TAPlA,VICTORIA; MUÑOZ,PATRICIA. |
| Cells tightly regulate iron levels through the activity of iron regulatory proteins (IRPs) that bind to RNA motifs called iron responsive elements (IREs). When cells become iron-depleted, IRPs bind to IREs present in the mRNAs of ferritin and the transferrin receptor, resulting in diminished translation of the ferritin mRNA and increased translation of the transferrin receptor mRNA. Similarly, body iron homeostasis is maintained through the control of intestinal iron absorption. Intestinal epithelia cells sense body iron through the basolateral endocytosis of plasma transferrin. Transterrin endocytosis results in enterocytes whose iron content will depend on the iron saturation of plasma transferrin. Cell iron levels, in turn, inversely correlate with... |
| Tipo: Journal article |
Palavras-chave: Metal ions; Intestinal absorption; Ferritin; Transferrin; Homeostasis. |
| Ano: 2000 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602000000200013 |
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