Receptor internalization is recognized as an important mechanism for rapidly regulating cell surface numbers of receptors. However, there are conflicting results on the existence of rapid endocytosis of ␥-aminobutyric acid, type B (GABA B ) receptors. Therefore, we analyzed internalization of GABA B receptors expressed in HEK 293 cells qualitatively and quantitatively using immunocytochemical, cell surface enzyme-linked immunosorbent assay, and biotinylation methods. The data indicate the existence of rapid constitutive receptor internalization, with the first endocytosed receptors being observed in proximity of the plasma membrane after 10 min. After 120 min, a loss of about 40 -50% of cell surface receptors was detected. Stimulation of GABA B receptors with GABA or baclofen did not enhance endocytosis of receptors, indicating the lack of agonistinduced internalization. The data suggest that GABA B receptors were endocytosed via the classical dynamin-and clathrin-dependent pathway and accumulated in an endosomal sorting compartment before being targeted to lysosomes for degradation. No evidence for recycling of receptors back to the cell surface was found. In conclusion, the results indicate the presence of constitutive internalization of GABA B receptors via clathrincoated pits, which resulted in lysosomal degradation of the receptors. GABA B3 receptors are G protein-coupled receptors that play an important role in the control of neurotransmission. They are widely expressed in the nervous system and have been implicated as potential targets for neurological diseases, such as epilepsy, pain, spasticity, addiction, schizophrenia, depression, and anxiety (for a review, see Ref. 1). GABA B receptors mediate slow inhibitory neurotransmission by either activating postsynaptically K ϩ channels or inhibiting presynaptically the release of neurotransmitters by modulation of Ca 2ϩ channels. On the structural level, functional GABA B receptors require the heterodimerization of two distinct seven-transmembrane proteins, termed GABA B1 and GABA B2 (2-7). Two main variants of GABA B1 have been reported (GABA B1a and GABA B1b (8)), which are generated by alternative promoter usage (9) and differ solely in their N-terminal domain. Heterodimerization of GABA B1a or GABA B1b with GABA B2 leads to two main GABA B receptor subtypes, GABA B1a /GABA B2 and GABA B1b /GABA B2 , which are abundantly expressed in all major brain structures (10 -13).An important aspect in the regulation of G protein-coupled receptors is their internalization or endocytosis. To protect cells against receptor overstimulation, the vast majority of G protein-coupled receptors desensitize upon prolonged agonist exposure, followed by rapid internalization. Many G protein-coupled receptors undergo phosphorylation upon agonist exposure by a G protein receptor kinase and subsequently recruit an arrestin protein (14). Arrestins often enhance phosphorylation, sterically interfere with binding of the G protein, and function as a signal for receptor endocytosis (15)...

The paper deals with systems for monitoring and protection of wildanimals in their natural environments and the use IoT technologies and solutionsin protected nature reserves. The paper also examines the reasons and possibilitiesfor implementing the above mentioned technical solutions, especially in termsof protecting species from the red list of endangered species. In this sense, thepaper also discusses technological solutions and the possibilities of applying IoTworking framework, the concept of the Internet of animals, and the application ofthese technologies through various business and research models. Finally, the paperprovides examples of solutions from the point of view of the necessary infrastructure(servers, storage, internet, animal necklaces, stationary cameras and drones), aswell as from the point of view of data processing and the legal framework for theapplication of these solutions.

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Internet stvari (eng. Internet of Things, IoT) je niz tehnologija za povezivanje nainternet uređaja kao što su senzori, laboratorijska i druga merna oprema koji prikupljajuinformacije od značaja i njihovo slanje prema serverima smeštenim u oblakuna kojima se vrši agregacija podataka i njihovo pretvaranje u informacije i izveštavanjenad njima prema potrebama različitih zainteresovanih strana. IoT tehnologijazasniva se na projektovanju i izradi vertikalnih rešenja za izveštavanje korisnika sistemao događajima i procesima od interesa. Poslednjih godina razvijeno je niz vertikalnihIoT rešenja u stočarstvu i veterini kojima se omogućavaju telemedicina,totalno praćenje lanaca snabdevanja prehrambenim proizvodima te informacije ozdravstvenom stanju stoke. Kao suštinski revolucionarna tehnologija, IoT bi mogaotransformisati način na koji posluje agrarni sektor, ali i način na koji se kontroliše ivrši upravljanje bezbednošću prehrambenih proizvoda.

Универзитет Унион-Никола Тесла, Факултет за стратешки и оперативни менаџмент, Београд, Србија Бранко Марковић Aksiom Softver Development, Београд, Србија Сажетак: Интернет је драстично променио начин пословања организација кроз развој електронске трговине, интернет маркетинга а нарочито кроз развој двосмерне комуникације између организација и циљне групе потрошача посредством друштвених мрежа. Све значајнија употреба друштвених мрежа у пословању утицала је и на спровођење све већег броја квантитативних, али и квалитативних истраживања у циљу ефикаснијег управљања и успешније експлоатације наведеног "виралног феномена". Управо је наведени тренд и иницирао да се у раду посебна пажња усмери на анализу секундарних резултата добијених током различитих истраживања у наведеној области, а све то у правцу адекватнијег сагледавања циљева, значаја и фреквенције употребе друштвених мрежа у пословању на глобалном тржишту, али и у пословању организација на територији Републике Србије. Кључне речи: интернет маркетинг, друштвене мреже, одржива конкурентна предност, интерактивна комуникација.Abstract: The Internet dramatically changed the way of business through the development of e-commerce, online marketing аnd particularly through the development of two-way communication between the organization and the target group of consumers. Significant use of social networks in business is also initiated a growing number of quantitative but also qualitative surveys aimed at more efficient management and successful exploitation of so-called "viral phenomenon". This trend are also initiated a special attention in this scientific paper on the analysis of objectives, importance and frequency of use of social networks in business in the global market and in business in organizations on the territory of the Republic of Serbia.