Klíšťata sají obrovské množství krve, která je jejich jediným zdrojem živin a energie. Přesný enzymatický mechanismus zpracování krve ve střevě klíšťat však kupodivu nebyl donedávna vůbec znám. Náš komplexní molekulární model trávení hostitelského hemoglobinu u klíštěte obecného (Ixodes ricinus) poprvé odhalil analogii enzymatického aparátu s krevsajícími ploštěnci a hlísticemi, a zároveň tato znalost představuje zásadní poznatek pro účinný boj s klíšťaty a jimi přenášenými patogeny., Ticks (in this case Ixodidae and Argasidae) feed on enormous amounts of host blood, which provides their ultimate source of energy and nutrients. There has been only limited evidence on the exact molecular mechanisms of blood digestion in ticks. For the first time, our complex enzymatic model of proteolytic digestion in the Common Tick (Ixodes ricinus) reveals the analogy of tick intestinal proteolysis with bloodfeeding platyhelminthes and nematodes and presents a future application potential in tick or tick-borne pathogen interventions., and Daniel Sojka.
V tomto článku je nastíněn základní úvod do problematiky biotransformace a jejich možných negativních důsledků. V textu jsou popsány tři fáze biotransformace a u každé z nich případ, se kterým se čtenář ve svém životě může setkat. Dále je zde jednoduchým způsobem vysvětlena nomenklatura biotransformačních enzymů a transportérů a článek tak celkově poskytuje základní povědomí o komplexnosti biotransformace., This article outlines a basic introduction to the topic of biotransformation and its possible negative consequences. The text describes three phases of biotransformation and each is presented in an example which the reader may encounter in everyday life. Furthermore, in a simple way, the nomenclature of biotransformation enzymes and transporters is explained and thus the paper provides a basic understanding of the complexity of biotransformation., and Ondřej Ženata.
Steroid sulfatase (EC 3.1.6.2) is an important enzyme involved in steroid hormone metabolism. It catalyzes the hydrolysis of steroid sulfates into their unconjugated forms. This action rapidly changes their physiological and biochemical properties, especially in brain and neural tissue. As a result, any imbalance in steroid sulfatase activity may remarkably influence physiological levels of active steroid hormones with serious consequences. Despite that the structure of the enzyme has been completely resolved there is still not enough information about the regulation of its expression and action in various tissues. In the past few years research into the enzyme prope ties and regulations has been strongly driven by the discovery of its putative role in the indirect stimulation of the growth of hormone-dependent tumors of the breast and prostate., L. Kříž, M. Bičíková, R. Hampl., and Obsahuje bibliografii a bibliografické odkazy
This study was designed to investigate effect of alpha-lipoic acid (LA) on lipid peroxidation, nitric oxide production and antioxidant systems in rats exposed to chronic restraint stress. Twenty four male Wistar rats, aged three months, were divided into four groups: control (C), the group treated with LA (L), the group exposed to restraint stress (S) and the group exposed to stress and treated with LA (LS). Restraint stress was applied for 21 days (1 h/day) and LA (100 mg/kg/day) was injected intraperitonally to the L and LS groups for the same period. Restraint stress significantly decreased brain copper/zinc superoxide dismutase (Cu,Zn-SOD) and brain and retina glutathione peroxidase (GSH-Px) and catalase (CAT) activities compared with the control group. Thiobarbituric acid reactive substances (TBARS), nitrite and nitrate levels were significantly increased in the tissues of the S group compared with the C group. LA produced a significant decrease in brain and retina TBARS, nitrite and nitrate levels of the L and LS groups compared to their corresponding control groups. LA increased all enzyme activities in the tissues of the LS group compared to the S group. Our study indicated that LA is an ideal antioxidant candidate for the prevention of stress-induced lipid peroxidation., D. Akpinar, P. Yargiçoğlu, N. Derin, Y. Alicigüzel, A. Ağar., and Obsahuje bibliografii a bibliografické odkazy