Homeostasis as the Mechanism of Evolution.

Homeostasis is conventionally thought of merely as a synchronic (same time) servo-mechanism that maintains the status quo for organismal physiology. However, when seen from the perspective of developmental physiology, homeostasis is a robust, dynamic, intergenerational, diachronic (across-time) mechanism for the maintenance, perpetuation and modification of physiologic structure and function. The integral relationships generated by cell-cell signaling for the mechanisms of embryogenesis, physiology and repair provide the needed insight to the scale-free universality of the homeostatic principle, offering a novel opportunity for a Systems approach to Biology. Starting with the inception of life itself, with the advent of reproduction during meiosis and mitosis, moving forward both ontogenetically and phylogenetically through the evolutionary steps involved in adaptation to an ever-changing environment, Biology and Evolution Theory need no longer default to teleology

IRBIT a Master Regulator of Cell Physiology

(excerpt) Hormones and neurotransmitters regulate cell functions by binding to their receptors, which activate intracellular signaling and produce the physiological response [1]. There are several intracellular pathways, including but not limited to, leading to the activation of protein kinases, phosphatases and increase in intracellular calcium (Ca2+) [1]

Impact of cell physiology and densities during oxidative axenic cultures of Yarrowia lipolytica on physico-chemical properties of broth

Impact of cell physiology and densities during oxidative axenic cultures of Yarrowia lipolytica on physico-chemical properties of brot

Rheology at the micro-scale: new tools for bio-analysis

We present a simple and non-invasive experimental procedure to measure the linear viscoelastic properties of cells by passive particle tracking microrheology. In order to do this, a generalised Langevin equation is adopted to relate the timedependent thermal fluctuations of a probe sensor, immobilised to the cell’s membrane, to the frequency-dependent viscoelastic moduli of the cell. The method has been validated by measuring the linear viscoelastic response of a soft solid and then applied to cell physiology studies. It is shown that the viscoelastic moduli are related to the cell’s cytoskeletal structure, which in this work is modulated either by inhibiting the actin/myosin-II interactions by means of blebbistatin or by varying the solution osmolarity from iso- to hypo-osmotic conditions. The insights gained from this form of rheological analysis promises to be a valuable addition to physiological studies; e.g. cell physiology during pathology and pharmacological response

Administration of Vitamin D Metabolites Affects RNA Expression of Xenobiotic Metabolising Enzymes and Function of ABC Transporters in Rats

From studies on different species and in cell culture systems, it has been suggested that vitamin D metabolites might affect themetabolism and elimination of xenobiotics. Although most studies performed on rodents and cell cultures report an upregulationof respective enzymes and transporters, data from the literature are inconsistent. Especially results obtained with sheep differ fromthese observations. As vitamin D metabolites are widely used as feed additives or therapeutics in livestock animals, we aimed toassess whether these differences indicate species-specific responses or occurred due to the very high dosages used in the rodentstudies. -erefore, we applied treatment protocols to rats that had been used previously in sheep or cattle. Forty-eight female ratswere divided into three treatment and corresponding placebo groups: (1) a single intraperitoneal injection of 1,25-(OH)2D3 orplacebo 12 h before sacrifice; (2) daily supplementation with 25-OHD3 by oral gavage or placebo for 10 days; and (3) a singleintramuscular injection of vitamin D3 10 days before sacrifice. In contrast to a previous study using sheep, treatment of rats with1,25-dihydroxyvitamin D3 did not result in an upregulation of cytochrome P450 3A isoenzymes (CYP3A), but a decrease wasfound in hepatic and intestinal expressions. In addition, a downregulation of P-glycoprotein (P-gp) and breast cancer resistanceprotein was found in the brain. Taken together, the stimulating effects of vitamin D metabolites on the expression of genesinvolved in the metabolism and elimination of xenobiotics reported previously for rodents and sheep could not be reproduced. Incontrast, we even observed a negative impact on the expression of CYP3A enzymes and their most important regulator, thepregnane X receptor. Most interestingly, we could demonstrate an effect of treatment with 25-hydroxyvitamin D3 and vitamin D3on the functional activity of ileal P-glycoprotein (P-gp) using the Ussing chamber technique.Fil: Klumpp, Karoline. University of Veterinary Medicine Hannover. Institute of Physiology and Cell Biology; AlemaniaFil: Lange, Frauke. University of Veterinary Medicine Hannover. Institute of Physiology and Cell Biology; AlemaniaFil: Muscher-Banse, Alexandra S.. University of Veterinary Medicine Hannover. Institute of Physiology and Cell Biology; AlemaniaFil: Schnepel, Nadine. University of Veterinary Medicine Hannover. Institute of Physiology and Cell Biology; AlemaniaFil: Hansen, Kathrin. University of Veterinary Medicine Hannover. Institute of Physiology and Cell Biology; AlemaniaFil: Lifschitz, Adrian Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Maté, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; ArgentinaFil: Wilkens, Mirja. University of Veterinary Medicine Hannover. Institute of Physiology and Cell Biology; Alemani

Mammary stem cell research in veterinary science : an update

The mammary gland is an organ with a remarkable regenerative capacity that can undergo multiple cycles of proliferation, lactation, and involution. Growing evidence suggests that these changes are driven by the coordinated division and differentiation of mammary stem cell populations (MaSC). Whereas information regarding MaSC and their role in comparative mammary gland physiology is readily available in human and mice, such information remains scarce in most veterinary mammal species such as cows, horses, sheep, goats, pigs, and dogs. We believe that a better knowledge on the MaSC in these species will not only help to gain more insights into mammary gland (patho) physiology in veterinary medicine, but will also be of value for human medicine. Therefore, this review summarizes the current knowledge on stem cell isolation and characterization in different mammals of veterinary importance

Reductive Biotransformation of Ethyl Acetoacetate: A Comparative Studies using Free and Immobilized Whole Yeast Cells

Bioreduction of ethyl acetoacetate with free and immobilized yeast whole cell was achieved by using water and sucrose combination. After detachment from immobilized beads under basic condition, the corresponding ethyl(S)-(+)-3-hydroxybutanoate was isolated with 98 to 100% yield. Immobilized beads of yeast whole cell were prepared at different temperature which affects the morphology and physiology of the beads for the diffusion of the enzyme, which shown the maximum conversion of the substrate to products as compared to the free yeast whole cell

The Mitochondrial Ca(2+) Uniporter: Structure, Function, and Pharmacology.

Mitochondrial Ca(2+) uptake is crucial for an array of cellular functions while an imbalance can elicit cell death. In this chapter, we briefly reviewed the various modes of mitochondrial Ca(2+) uptake and our current understanding of mitochondrial Ca(2+) homeostasis in regards to cell physiology and pathophysiology. Further, this chapter focuses on the molecular identities, intracellular regulators as well as the pharmacology of mitochondrial Ca(2+) uniporter complex