3-D struktura serumske paraoksonaze 1 objašnjava njezinu aktivnost, stabilnost, topljivost i kristalizaciju

Serum paraoxonases (PONs) exhibit a wide range of physiologically important hydrolytic activities, including drug metabolism and detoxification of nerve gases. PON1 and PON3 reside on high-density lipoprotein (HDL) (the “good cholesterol”), and are involved in the alleviation of atherosclerosis. Members of the PON family have been identified not only in mammals and other vertebrates, but also in invertebrates. We earlier described the first crystal structure of a PON family member, a directly-evolved variant of PON1, at 2.2 Å resolution. PON1 is a 6-bladed beta-propeller with a unique active-site lid which is also involved in binding to HDL. The 3-D structure, taken together with directed evolution studies, permitted analysis of mutations which enhanced the stability, solubility and crystallizability of this PON1 variant. The structure permits a detailed description of PON1’s active site and suggests possible mechanisms for its catalytic activity on certain substrates.Serumske paraoksonaze (PONs) imaju široki raspon fiziološki važnih hidrolitičkih aktivnosti uključujući metabolizam lijekova i detoksikaciju nervnih plinova. PON1 i PON3 smještene su na lipoproteinima visoke gustoće (engl. high-density lipoprotein; HDL - “dobri kolesterol”) i uključene su u ublažavanje ateroskleroze. Članovi skupine PON identificirani su ne samo u sisavaca i drugih kralježnjaka već i kod beskralješnjaka. Prije smo opisali prvu kristalnu strukturu člana PON skupine, direktno razrađenu varijantu PON1 pri rezoluciji 2,2 Å. PON1 je beta-propeler sa šest lopatica s jedinstvenim poklopcem aktivnog mjesta, koji je tako|er uključen u vezanje na HDL. 3-D struktura, gledana zajedno s direktnim razvojnim istraživanjima, omogućila je analizu mutacija koje povećavaju stabilnost, topljivost i kristalizaciju te PON1 varijante. Struktura dopušta detaljan opis aktivnog mjesta PON1 i sugerira moguće mehanizme za njezinu katalitičku aktivnost prema odre|enim supstratima

Preventive effect of N-stearoylethanolamine on memory disorders, blood and brain biochemical parameters in rats with experimental scopolamine-induced cognitive impairment

The impairment of cognitive functions is the most studied medical and social problem nowadays. The aim of this study was to evaluate the protective effects of N-stearoylethanolamine (NSE) on memory state, blood and brain biochemical parameters in rats under scopolamine-induced cognitive impairment. The results of this study shown that NSE administration to rats per os (5 mg/kg, 5 days, during last 3 days NSE was administrated 20 min prior to scopolamine injection (1 mg/kg, once daily for 3 days, intraperitoneally)) prevented the development of memory impairment. In particular, NSE action was associated with the prevention of increase in acetylcholinesterase activity, changes in phospholipid, free and esterified cholesterol level in hippocampus and frontal cortex, and disruption in pro-/antioxidant balance in blood and studied brain sections. Considering the above mentioned biological effects, NSE is a promising drug candidate for integrative therapy of cognitive impairment of different profiles

Evaluation of Cavitation Erosion Behavior of Commercial Steel Grades Used in the Design of Fluid Machinery

The erosion response under cavitation of different steel grades was assessed by studying the erosion rate, the volume removal, the roughness evolution, and the accumulated strain energy. A 20 kHz ltrasonic transducer with a probe diameter of 5 mm and peak-to-peak amplitude of 50 lm was deployed in distilled water to induce damage on the surface of commercial chromium and carbon steel samples. After a relatively short incubation period, cavitation induced the formation of pits, cracks, and craters whose features strongly depended on the hardness and composition of the tested steel. AISI 52100 chromium steel showed the best performance and is, therefore, a promising design candidate for replacing the existing fluid machinery materials that operate within potential cavitating environments