Julius Liobikas

We have searched through plant databases for nucleotide and protein sequences sharing a significant similarity to bacterial serine β-lactamases and metazoan LACTB. The search resulted in the identification of novel serine β-lactamase homologues in both Gymno- and Angiosperms.

Thaumatin-II is an intense sweet tasting protein isolated from fruits of Thaumatococcus daniellii. Thaumatin is a member of the pathogenesis-related protein family referred to as thaumatinlike proteins (TLPs). Expression of thaumatin-II in plants was associated with an enhanced resistance against pathogens. In addition, thaumatin was used to provide the sweet taste quality to plant products. Thus, TLP proteins have a potential application for improving plant stress resistance and taste qualities using the recombinant DNA technology.

LACTB is a mammalian active-site serine protein that has evolved from a bacterial penicillin-binding protein. Penicillin-binding proteins are involved in the metabolism of peptidoglycan, the major bacterial cell wall constituent, implying that LACTB has been endowed with novel biochemical properties during eukaryote evolution. Here we demonstrate that LACTB is localized in the mitochondrial intermembrane space, where it is polymerized into stable filaments with a length extending more than a hundred nanometers.

K(ATP) channel openers protect ischemic-reperfused myocardium by mimicking ischemic preconditioning, however, the protection mechanisms have not been fully clarified yet. Since the skinned fibers technique gives an opportunity to investigate an entire population of mitochondria in their native milieu, in this study we have investigated the effects of K(ATP) channel openers pinacidil and diazoxide on the respiration rate of rat heart mitochondria in situ, oxidizing physiological substrates pyruvate and malate (6+6 mM).

Ursolic acid (1), a pentacyclic triterpene acid, is one of the major components of certain traditional medicinal plants and possesses a wide range of biological effects, such as anti-inflammatory, antioxidative, and cytotoxic activities. Furthermore, 1, when present at 1.6-5 ng/mL concentrations in commercial herbal preparations used for patients with cardiac disorders, may also exert pro-cardiac activities.

The aim of this study was to investigate free radical-scavenging activity of Salvia officinalis L., Thymus vulgaris L., Urtica dioica L. extracts and mixture of extracts, and to evaluate the effect of these extracts on the ability of mitochondria to generate free radicals. The evaluation of the activity of extracts using 2,2-diphenyl-1-picrylhydrazyl (DDPH), 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) radicals scavenging assays and tyrosine nitration inhibition (TNI) techniques showed that thyme extract had the strongest free-radical-scavenging activity.

In this study, the direct influence of bilberry (Vaccinium myrtillus) fruit extracts (aqueous and ethanolic) rich in anthocyanins on the oxidative phosphorylation of isolated rat heart mitochondria was investigated in vitro. Higher concentrations of bilberry extracts concentration-dependently inhibited mitochondrial state 3 respiration (by 23%-61%) with pyruvate plus malate, mildly (by 1.2- to 1.3-fold) uncoupled the oxidative phosphorylation, and increased (by 30%-87%) the state 4 respiration rate in the presence of exogenous cytochrome c.

Anthocynanins, found in fruits and vegetables, have a variety of protective properties, which have generally been attributed to their antioxidant capacity. However, antioxidants are generally strong reductants, and some reductants have been found to block apoptosis by reducing cytosolic cytochrome c, which prevents caspase activation. We tested the ability of various anthocyanins: to reduce cytochrome c, to support cytochrome c-induced mitochondrial respiration and to inhibit apoptosis induced by heart ischemia.