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The vacuolar H+‐ATPase (V‐ATPase) plays a crucial role in facilitating nutrient ions storage in vacuoles, whereas its direct impact on vacuolar phosphate (Pi) accumulation has not been fully elucidated. Previous research revealed that the absence of VPT1 and VPT3, two major vacuolar Pi influx transporters, significantly affected vacuolar Pi storage. This study shows that disrupting V‐ATPase function could mimic the vpt1 vpt3 mutant phenotypes. The vha‐a2 a3 mutant, lacking V‐ATPase activity, had lower vacuolar Pi levels, higher cytoplasmic Pi and increased resistance to As(V) toxicity under sufficient Pi conditions. Complementation assays in Pi transport‐deficient yeast confirmed that high pH suppressed VPT1 activity, while overexpressing VPT1 couldn't overload Pi in vacuoles of vha‐a2 a3 mutants. These data illustrate the reliance of VPT1's activity on V‐ATPase‐generated proton gradients. Furthermore, we find V‐ATPase activity correlates positively with Pi availability, and varying across developmental stages. During flowering, V‐ATPase activity decreases to enhance Pi allocation in xylem sap for long‐distance transport when external Pi is replete, akin to the vpt1 vpt3 mutant. Thus, V‐ATPase could cooperate with VPT proteins to regulate Pi homeostasis at both subcellular and systemic levels. Summary Statement: In Arabidopsis, the proton gradient generated by V‐ATPase across the tonoplast regulates the activities of VACUOLAR PHOSPHATE TRANSPORTER1 family proteins, thereby controlling Pi homeostasis at both subcellular and systemic levels in response to external cues and internal demands. [ABSTRACT FROM AUTHOR]

Phenolic allelochemicals from root exudates dominate rhizosphere formation, lead to autotoxicity in plants subjected to continuous monoculture (CM) stress and induce the emergence of replant disease. However, the regulatory mechanisms governing the transport of phenolics from plant roots to the rhizosphere remain poorly understood. A potential phenolic efflux transporter from Rehmannia glutinosa, designated RgMATE35, has been preliminarily characterized. The objective of this study was to elucidate the molecular function of RgMATE35 in the secretion of phenolics and to investigate its role in the development of plant replant disease using quantitative real-time PCR (qRT-PCR), genetic transformation, HPLC-Q-TOF-MS and other analytical techniques. A tissue expression pattern analysis of RgMATE35 revealed that it is highly expressed in plant roots. Transient expression analysis confirmed the localization of the protein in plasma membranes. An assessment of the transport activity of RgMATE35 in Xenopus oocytes indicated that it plays a role in facilitating the efflux of labeled ferulic acid ([2H3]-FA) and trans-p-coumaric acid [2H6]-pCA. The results of functional studies in R. glutinosa demonstrated that RgMATE35 positively mediates the secretion of FA and pCA from plant roots into the rhizosphere. A molecular and physiological analysis of RgMATE35 transgenic plants subjected to CM stress revealed that the overexpression or repression of RgMATE35 resulted in notable changes in the degree of autotoxic injury in plants. These findings demonstrate that RgMATE35 plays a positive role in the development of replant disease through the secretion of phenolic acids from plant roots. They also provide a fundamental framework for elucidating the molecular regulatory mechanism through which MATEs regulate replant disease through the root secretion of allelochemicals. [ABSTRACT FROM AUTHOR]

Manganese (Mn) is an indispensable mineral for plant growth and development. However, plants cultivated in acidic and poorly drained soils are vulnerable to Mn2+ toxicity due to its heightened increased bioavailability. Despite the crucial roles of the Rho of plant (ROP) GTPases in various cellular processes, their precise function in regulating Mn homeostasis remains elusive. In this study, we unveil a novel ROP6 GTPase signalling pathway that profoundly influences Mn phytotoxicity tolerance in Arabidopsis. Remarkably, the rop6 and dominant‐negative ROP6 (rop6DN) mutant plants displayed a dramatically sensitive phenotype to Mn toxicity, whereas ROP6‐overexpression and constitutively activated ROP6 (rop6CA) lines exhibited enhanced Mn stress tolerance. Immunoblot analysis corroborated that the ROP6 protein, especially the active form of ROP6, increased in abundance in the presence of high Mn levels. Further, we identified that ROP6 physically interacted and colocalized with Metal Tolerance Protein 8 (MTP8) in vivo. Mn transport complementation assays in yeast, combined with biochemical analyses, emphasized the essentiality of ROP6 for MTP8's transport activity. In addition, genetic analyses indicated that ROP6 acted upstream of MTP8 in the regulatory cascade. Collectively, our findings elucidate that ROP6 GTPase signalling positively modulates and enhances Mn stress tolerance in plants. Summary statement: ROP6 GTPase signalling pathway enhances manganese (Mn) tolerance in Arabidopsis by regulating Mn homeostasis through interaction with Metal Tolerance Protein 8 (MTP8). This discovery offers potential genetic strategies to mitigate Mn toxicity in plants. [ABSTRACT FROM AUTHOR]

Pdr5 is the most abundant ABC transporter in Saccharomyces cerevisiae and plays a major role in the pleiotropic drug resistance (PDR) network, which actively prevents cell entry of a large number of structurally unrelated compounds. Due to a high level of asymmetry in one of its nucleotide binding sites (NBS), Pdr5 serves as a perfect model system for asymmetric ABC transporter such as its medical relevant homologue Cdr1 from Candida albicans. In the past 30 years, this ABC transporter was intensively studied in vivo and in plasma membrane vesicles. Nevertheless, these studies were limited since it was not possible to isolate and reconstitute Pdr5 in a synthetic membrane system while maintaining its activity. Here, the functional reconstitution of Pdr5 in a native‐like environment in an almost unidirectional inside‐out orientation is described. We demonstrate that reconstituted Pdr5 is capable of translocating short‐chain fluorescent NBD lipids from the outer to the inner leaflet of the proteoliposomes. Moreover, this transporter revealed its ability to utilize other nucleotides to accomplish transport of substrates in a reconstituted system. Besides, we were also able to estimate the NTPase activity of reconstituted Pdr5 and determine the kinetic parameters for ATP, GTP, CTP, and UTP. [ABSTRACT FROM AUTHOR]

Renal tubules are featured with copious mitochondria and robust transport activity. Mutations in mitochondrial genes cause congenital renal tubulopathies, and changes in transport activity affect mitochondrial morphology, suggesting mitochondrial function and transport activity are tightly coupled. Current methods of using bulk kidney tissues or cultured cells to study mitochondrial bioenergetics are limited. Here, we optimized an extracellular flux analysis (EFA) to study mitochondrial respiration and energy metabolism using microdissected mouse renal tubule segments. EFA detects mitochondrial respiration and glycolysis by measuring oxygen consumption and extracellular acidification rates, respectively. We show that both measurements positively correlate with sample sizes of a few centimeter‐length renal tubules. The thick ascending limbs (TALs) and distal convoluted tubules (DCTs) critically utilize glucose/pyruvate as energy substrates, whereas proximal tubules (PTs) are significantly much less so. Acute inhibition of TALs' transport activity by ouabain treatment reduces basal and ATP‐linked mitochondrial respiration. Chronic inhibition of transport activity by 2‐week furosemide treatment or deletion of with‐no‐lysine kinase 4 (Wnk4) decreases maximal mitochondrial capacity. In addition, chronic inhibition downregulates mitochondrial DNA mass and mitochondrial length/density in TALs and DCTs. Conversely, gain‐of‐function Wnk4 mutation increases maximal mitochondrial capacity and mitochondrial length/density without increasing mitochondrial DNA mass. In conclusion, EFA is a sensitive and reliable method to investigate mitochondrial functions in isolated renal tubules. Transport activity tightly regulates mitochondrial bioenergetics and biogenesis to meet the energy demand in renal tubules. The system allows future investigation into whether and how mitochondria contribute to tubular remodeling adapted to changes in transport activity. [ABSTRACT FROM AUTHOR]

Phenolic allelochemicals from root exudates dominate rhizosphere formation, lead to autotoxicity in plants subjected to continuous monoculture (CM) stress and induce the emergence of replant disease. However, the regulatory mechanisms governing the transport of phenolics from plant roots to the rhizosphere remain poorly understood. A potential phenolic efflux transporter from Rehmannia glutinosa, designated RgMATE35, has been preliminarily characterized. The objective of this study was to elucidate the molecular function of RgMATE35 in the secretion of phenolics and to investigate its role in the development of plant replant disease using quantitative real-time PCR (qRT-PCR), genetic transformation, HPLC-Q-TOF-MS and other analytical techniques. A tissue expression pattern analysis of RgMATE35 revealed that it is highly expressed in plant roots. Transient expression analysis confirmed the localization of the protein in plasma membranes. An assessment of the transport activity of RgMATE35 in Xenopus oocytes indicated that it plays a role in facilitating the efflux of labeled ferulic acid ([2H3]-FA) and trans-p-coumaric acid [2H6]-pCA. The results of functional studies in R. glutinosa demonstrated that RgMATE35 positively mediates the secretion of FA and pCA from plant roots into the rhizosphere. A molecular and physiological analysis of RgMATE35 transgenic plants subjected to CM stress revealed that the overexpression or repression of RgMATE35 resulted in notable changes in the degree of autotoxic injury in plants. These findings demonstrate that RgMATE35 plays a positive role in the development of replant disease through the secretion of phenolic acids from plant roots. They also provide a fundamental framework for elucidating the molecular regulatory mechanism through which MATEs regulate replant disease through the root secretion of allelochemicals.

The article reveals the place and role of transport law in the legal system of Ukraine and characterizes the peculiarities of transport relations, sources of transport law. It is noted that transport law is a complex sub-branch of law that combines norms of civil, economic, administrative, land, labor, commercial and a number of other branches of law. Transport law contains public-law and privatelaw norms that regulate social relations arising in the field of transport activities. Transport activity is accompanied, as a rule, by the conclusion of transport contracts. In its essence, transport law is more closely related to civil law, because property relations make up the material content of transport contracts, transport risk insurance contracts, legal situations of customs clearance of goods, etc. The main factor in property relations in the field of transport are transportation contracts, which are regulated by civil law. A special place is occupied by the protection of the property rights of the parties to obligations arising from transportation contracts. It is argued that transport activity includes both the physical movement of passengers, luggage, and cargo from the point of departure to the destination, as well as auxiliary services. Such activities are carried out on the basis of relevant transport contracts. This is the generalized name of all contracts that are regulated by the provision of certain transport services (transportation, forwarding, etc.). The main type of transport contracts is a contract of carriage. Article 908 of the Civil Code of Ukraine establishes the basic provisions regarding contracts for the carriage of cargo, passengers, and luggage, including liability for the main types of violations of obligations arising from carriage contracts; general regulations on transportation. The conditions of transportation of cargo, passengers and luggage by separate modes of transport, as well as the responsibilities of the parties regarding these transportations, are established by the contract, unless otherwise established by the Civil Code of Ukraine, other laws, transport codes (statutes), other normative legal acts and rules issued in accordance with them Transport activity, which is accompanied, as a rule, by the conclusion of transport contracts, gives rise to transport legal relations that arise in connection with the operation of transport for the purpose of providing transport services and carrying out related activities in the unity of the organizational-management and economic (civillaw) component of such exploitation The subjects of transport legal relations are state authorities and local self-government bodies in relations, in particular, regarding licensing of certain types of transport activities, approval of passports of transport routes, admission of carriers to the activity of transporting passages, etc.; suppliers of transportation transport services - railways, motor transport companies, airlines, etc., which provide relevant services on a contractual basis, at the same time observing certain requirements and standards established by the relevant state authorities; consumers of transport services, which in particular include passengers, consignors and consignees; various auxiliary participants in transport activities, in particular forwarders, agents, insurance companies, etc. The object of transport legal relations is activity related to the transportation of goods, passengers, luggage and mail. A distinction is made between the object of transport legal relations and the object (subject) of transportation. The first is a certain good, for example, a transportation service, for the purpose of which subjects enter into legal relations. The object of transportation is cargo, luggage, hand luggage, mail and, of course, a person-passenger. Sources of transport law, which are divided into international and national, are analyzed. [ABSTRACT FROM AUTHOR]

The human ABCB1 (P-glycoprotein, Pgp) protein is an active exporter expressed in the plasma membrane of cells forming biological barriers. In accordance with its broad substrate spectrum and tissue expression pattern, it affects the pharmacokinetics of numerous chemotherapeutic drugs and it is involved in unwanted drug–drug interactions leading to side effects or toxicities. When expressed in tumor tissues, it contributes to the development of chemotherapy resistance in malignancies. Therefore, the understanding of the molecular details of the ligand–ABCB1 interactions is of crucial importance. In a previous study, we found that quercetin (QUR) hampers both the transport and ATPase activity of ABCB1, while cyandin-3O-sophroside (C3S) stimulates the ATPase activity and causes only a weak inhibition of substrate transport. In the current study, when QUR and C3S were applied together, both a stronger ATPase inhibition and a robust decrease in substrate transport were observed, supporting their synergistic ABCB1 inhibitory effect. Similar to cyclosporine A, a potent ABCB1 inhibitor, co-treatment with QUR and C3S shifted the conformational equilibrium to the "inward-facing" conformer of ABCB1, as it was detected by the conformation-selective UIC2 mAb. To gain deeper insight into the molecular details of ligand–ABCB1 interactions, molecular docking experiments and MD simulations were also carried out. Our in silico studies support that QUR and C3S can bind simultaneously to ABCB1. The most favourable ligand–ABCB1 interaction is obtained when C3S binds to the central substrate binding site and QUR occupies the "access tunnel". Our results also highlight that the strong ABCB1 inhibitory effect of the combined treatment with QUR and C3S may be exploited in chemotherapy protocols for the treatment of multidrug-resistant tumors or for improving drug delivery through pharmacological barriers. [ABSTRACT FROM AUTHOR]

Summary: Cadmium (Cd) is a toxic heavy element for plant growth and development, and plants have evolved many strategies to cope with Cd stress. However, the mechanisms how plants sense Cd stress and regulate the function of transporters remain very rudimentary.Here, we found that Cd stress induces obvious Ca2+ signals in Arabidopsis roots. Furthermore, we identified the calcium‐dependent protein kinases CPK21 and CPK23 that interacted with the Cd transporter NRAMP6 through a variety of protein interaction techniques.Then, we confirmed that the cpk21 23 double mutants significantly enhanced the sensitive phenotype of cpk23 single mutant under Cd stress, while the overexpression and continuous activation of CPK21 and CPK23 enhanced plants tolerance to Cd stress. Multiple biochemical and physiological analyses in yeast and plants demonstrated that CPK21/23 phosphorylate NRAMP6 primarily at Ser489 and Thr505 to inhibit the Cd transport activity of NRAMP6, thereby improving the Cd tolerance of plants.Taken together, we found a plasma membrane‐associated calcium signaling that modulates Cd tolerance. These results provide new insights into the molecular breeding of crop tolerance to Cd stress. [ABSTRACT FROM AUTHOR]

The excessive increase in transport intensity is one of the negative impacts on the economy. The costs borne due to transport activities are indirectly expressed by the volume of carriages (in tons) and by the scope of transport activity (in ton-kilometers). The result of social and economic activities are global product values and national incomes. This article shows the research on transport activity expressed through transport activity (in ton-kilometers) for all means of transport in total, the results of social and economic activities expressed using the gross domestic product, as well as shaping transport intensity of national economies in selected European countries. The analysis of the course of the exponential function curves, as well as polynomial curves has been carried out, and conclusions have been formulated on their bases.

Excess phosphate (Pi) is stored into the vacuole through Pi transporters so that cytoplasmic Pi levels remain stable in plant cells. We hypothesized that the vacuolar Pi transporters may harbor a Pi-sensing mechanism so that they are activated to deliver Pi into the vacuole only when cytosolic Pi reaches a threshold high level. We tested this hypothesis using Vacuolar Phosphate Transporter 1 (VPT1), a SPX domain-containing vacuolar Pi transporter, as a model. Recent studies have defined SPX as a Pi-sensing module that binds inositol polyphosphate signaling molecules (InsPs) produced at high cellular Pi status. We showed here that Pi-deficient conditions or mutation of the SPX domain severely impaired the transport activity of VPT1. We further identified an auto-inhibitory domain in VPT1 that suppresses its transport activity. Taking together the results from detailed structure-function analyses, our study suggests that VPT1 is in the auto-inhibitory state when Pi status is low, whereas at high cellular Pi status InsPs are produced and bind SPX domain to switch on VPT1 activity to deliver Pi into the vacuole. This thus provides an auto-regulatory mechanism for VPT1-mediated Pi sensing and homeostasis in plant cells. This study reveals that VPT1, a SPX domain transporter that delivers Pi into the vacuole, senses cellular Pi status to control the transport activity. The soluble N-terminal region serves as auto-inhibitory domain that keeps VPT1 in an inactive state under low Pi conditions, whereas elevated cellular Pi produces InsPs signals that bind to SPX domain and release the transport activity of VPT1. [ABSTRACT FROM AUTHOR]

Heat stress (HS) poses a significant threat to production and survival in the global swine industry. However, the molecular regulatory effects of heat stress on maternal endometrial cells are poorly understood in pigs during early embryo implantation. In this study, we systematically examined morphological changes in the endometrium and the corresponding regulation mechanism in response to HS by combining scanning electron microscopy (SEM), hematoxylin/eosin (H&E) staining, western blot, and RNA-seq analyses. Our results showed that HS led to porcine endometrium damage and endometrial thinness during embryo implantation. The expression levels of cell adhesion-related proteins, including N-cadherin and E-cadherin, in the uterus were significantly lower in the heat stress group (39 ± 1 °C, n = 3) than in the control group (28 ± 1 °C, n = 3). A total of 338 up-regulated genes and 378 down-regulated genes were identified in porcine endometrium under HS. The down-regulated genes were found to be mainly enriched in the pathways related to the microtubule complex, immune system process, and metalloendopeptidase activity, whereas the up-regulated genes were mainly involved in calcium ion binding, the extracellular region, and molecular function regulation. S100A9 was found to be one of the most significant differentially expressed genes (DEGs) in the endometrium under HS, and this gene could promote proliferation of endometrial cells and inhibit their apoptosis. Meanwhile, HS caused endometrial epithelial cell (EEC) damage and inhibited its proliferation. Overall, our results demonstrated that HS induced uterine morphological change and tissue damage by regulating the expression of genes associated with calcium ions and amino acid transport. These findings may provide novel molecular insights into endometrial damage under HS during embryo implantation. [ABSTRACT FROM AUTHOR]

Pdr5 is the most abundant ABC transporter in Saccharomyces cerevisiae and plays a major role in the pleiotropic drug resistance (PDR) network, which actively prevents cell entry of a large number of structurally unrelated compounds. Due to a high level of asymmetry in one of its nucleotide binding sites (NBS), Pdr5 serves as a perfect model system for asymmetric ABC transporter such as its medical relevant homologue Cdr1 from Candida albicans. In the past 30 years, this ABC transporter was intensively studied in vivo and in plasma membrane vesicles. Nevertheless, these studies were limited since it was not possible to isolate and reconstitute Pdr5 in a synthetic membrane system while maintaining its activity. Here, the functional reconstitution of Pdr5 in a native-like environment in an almost unidirectional inside-out orientation is described. We demonstrate that reconstituted Pdr5 is capable of translocating short-chain fluorescent NBD lipids from the outer to the inner leaflet of the proteoliposomes. Moreover, this transporter revealed its ability to utilize other nucleotides to accomplish transport of substrates in a reconstituted system. Besides, we were also able to estimate the NTPase activity of reconstituted Pdr5 and determine the kinetic parameters for ATP, GTP, CTP, and UTP., (© 2024 The Author(s). Protein Science published by Wiley Periodicals LLC on behalf of The Protein Society.)

The excessive increase in transport intensity is one of the negative impacts on the economy. The costs borne due to transport activities are indirectly expressed by the volume of carriages (in tons) and by the scope of transport activity (in ton-kilometers). The result of social and economic activities are global product values and national incomes. This article shows the research on transport activity expressed through transport activity (in ton-kilometers) for all means of transport in total, the results of social and economic activities expressed using the gross domestic product, as well as shaping transport intensity of national economies in selected European countries. The analysis of the course of the exponential function curves, as well as polynomial curves has been carried out, and conclusions have been formulated on their bases. [ABSTRACT FROM AUTHOR]

The mitochondrial citrate transporter (MCT) plays an important role in citrate efflux from the mitochondria in eukaryotes, and hence provides a direct correlation between carbohydrate metabolism and lipid synthesis. Our previous studies on transporters confirmed the presence of two MCTs (TCT and CT) in oleaginous Mucor circinelloides WJ11 associated with high lipid accumulation. However, the molecular mechanism of citrate efflux from the mitochondria by MCT in M. circinelloides is still unclear. To study the citrate transport mechanism of CT, the citrate transporter gene was expressed in Escherichia coli, and its product was purified. The citrate transport activity of the protein was studied in CT reconstituted liposomes. Our results showed high efficiency of CT for [14C] citrate/citrate exchange with Km 0.01 mM at 25°C. Besides citrate, other molecules such as oxaloacetate, malate, fumarate, succinate aconitate, oxoadipate, isocitrate, and glutamate also promote citrate transport. In addition, the ct overexpression and knockout plasmids were constructed and transferred into M. circinelloides WJ11, and the mitochondria were isolated, and the transport activity was studied. Our findings showed that in the presence of 10 mM malate, the mitochondria of ct-overexpressing transformant showed 51% increase in the efflux rate of [14C] citrate, whereas the mitochondria of the ct-knockout transformant showed 18% decrease in citrate efflux compared to the mitochondria of wild-type WJ11. This study provided the first mechanistic evidence of citrate efflux from the mitochondria by citrate transporter in oleaginous filamentous fungus M. circinelloides, which is associated with high lipid accumulation.

The mitochondrial citrate transporter (MCT) plays an important role in citrate efflux from the mitochondria in eukaryotes, and hence provides a direct correlation between carbohydrate metabolism and lipid synthesis. Our previous studies on transporters confirmed the presence of two MCTs (TCT and CT) in oleaginous Mucor circinelloides WJ11 associated with high lipid accumulation. However, the molecular mechanism of citrate efflux from the mitochondria by MCT in M. circinelloides is still unclear. To study the citrate transport mechanism of CT, the citrate transporter gene was expressed in Escherichia coli , and its product was purified. The citrate transport activity of the protein was studied in CT reconstituted liposomes. Our results showed high efficiency of CT for [14C] citrate/citrate exchange with K m 0.01 mM at 25°C. Besides citrate, other molecules such as oxaloacetate, malate, fumarate, succinate aconitate, oxoadipate, isocitrate, and glutamate also promote citrate transport. In addition, the ct overexpression and knockout plasmids were constructed and transferred into M. circinelloides WJ11, and the mitochondria were isolated, and the transport activity was studied. Our findings showed that in the presence of 10 mM malate, the mitochondria of ct -overexpressing transformant showed 51% increase in the efflux rate of [14C] citrate, whereas the mitochondria of the ct -knockout transformant showed 18% decrease in citrate efflux compared to the mitochondria of wild-type WJ11. This study provided the first mechanistic evidence of citrate efflux from the mitochondria by citrate transporter in oleaginous filamentous fungus M. circinelloides , which is associated with high lipid accumulation. [ABSTRACT FROM AUTHOR]

Electrically powered rail vehicles are considered one of the most energy‐efficient means of transport. Transport activity is responsible for a considerable part of global energy consumption. The transport industry is therefore obliged to develop strategies for more efficient energy use. Railway electrification systems transmit the electrical power supplied by substations to moving trains. However, part of the power supplied is consumed by the electrification systems and does not reach the trains. In this study, transmission losses in the 2 × 25 kV electrification system are evaluated. The 2 × 25 kV system is widely used in high‐speed and high‐capacity railway lines. Assessment of the performance of the 2 × 25 kV system is carried out by computer simulation of the power flows between the elements involved in train movement by means of simplified physical models. The results show that the reduction of transmission losses is a feasible way to achieve energy savings and to improve the energy efficiency in electrified rail transport. For this, it is essential to add the topology of the electrification system to the data considered in the design of the train trajectories. [ABSTRACT FROM AUTHOR]

P-glycoprotein (Pgp, ABCB1) is a member of one of the largest families of active transporter proteins called ABC transporters. Thanks to its expression in tissues with barrier functions and its broad substrate spectrum, it is an important determinant of the absorption, metabolism and excretion of many drugs. Pgp and/or some other drug transporting ABC proteins (e.g., ABCG2, MRP1) are overexpressed in nearly all cancers and cancer stem cells by which cancer cells become resistant against many drugs. Thus, Pgp inhibition might be a strategy for fighting against drug-resistant cancer cells. Previous studies have shown that certain polyphenols interact with human Pgp. We tested the effect of 15 polyphenols of sour cherry origin on the basal and verapamil-stimulated ATPase activity of Pgp, calcein-AM and daunorubicin transport as well as on the conformation of Pgp using the conformation sensitive UIC2 mAb. We found that quercetin, quercetin-3-glucoside, narcissoside and ellagic acid inhibited the ATPase activity of Pgp and increased the accumulation of calcein and daunorubicin by Pgp-positive cells. Cyanidin-3O-sophoroside, catechin, naringenin, kuromanin and caffeic acid increased the ATPase activity of Pgp, while they had only a weaker effect on the intracellular accumulation of fluorescent Pgp substrates. Several tested polyphenols including epicatechin, trans-ferulic acid, oenin, malvin and chlorogenic acid were ineffective in all assays applied. Interestingly, catechin and epicatechin behave differently, although they are stereoisomers. We also investigated the effect of quercetin, naringenin and ellagic acid added in combination with verapamil on the transport activity of Pgp. In these experiments, we found that the transport inhibitory effect of the tested polyphenols and verapamil was additive or synergistic. Generally, our data demonstrate diverse interactions of the tested polyphenols with Pgp. Our results also call attention to the potential risks of drug–drug interactions (DDIs) associated with the consumption of dietary polyphenols concurrently with chemotherapy treatment involving Pgp substrate/inhibitor drugs.

Chun-Yang Wang,1,2 Shu Liu,1,2 Xiao-Nv Xie,1,2 Zhi-Rong Tan1,2 1Department of Clinical Pharmacology, Xiangya Hospital, Xiangya School of Medicine, Central South University, 2Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan, People’s Republic of China Abstract: The intestinal peptide transporter 1 (PepT1) was first identified in 1994. It plays a crucial role in the absorption of small peptides including not only >400 different dipeptides and 8,000 tripeptides digested from dietary proteins but also a repertoire of structurally related compounds and drugs. Owing to its critical role in the bioavailability of peptide-like drugs, such as the anti-cancer agents and anti-virus drug, PepT1 is increasingly becoming a striking prodrug-designing target. Therefore, the understanding of PepT1 gene regulation is of great importance both for dietary adaptation and for clinical drug treatment. After decades of research, it has been recognized that PepT1 could be regulated at the transcriptional and post-transcriptional levels by numerous factors. Therefore, the present review intends to summarize the progress made in the regulation of PepT1 and provide insights into the PepT1’s potential in clinical aspects of nutritional and drug therapies. Keywords: PepT1, dietary, regulation, transport activity, absorption, bioavailability

Abstract Background In birds, blue-green eggshell color (BGEC) is caused by biliverdin, a bile pigment derived from the degradation of heme and secreted in the eggshell by the shell gland. Functionally, BGEC might promote the paternal investment of males in the nest and eggs. However, little is known about its formation mechanisms. Jinding ducks (Anas platyrhynchos) are an ideal breed for research into the mechanisms, in which major birds lay BGEC eggs with minor individuals laying white eggs. Using this breed, this study aimed to provide insight into the mechanisms via comparative transcriptome analysis. Results Blue-shelled ducks (BSD) and white-shelled ducks (WSD) were selected from two populations, forming 4 groups (3 ducks/group): BSD1 and WSD1 from population 1 and BSD2 and WSD2 from population 2. Twelve libraries from shell glands were sequenced using the Illumina RNA-seq platform, generating an average of 41 million clean reads per library, of which 55.9% were mapped to the duck reference genome and assembled into 31,542 transcripts. Expression levels of 11,698 genes were successfully compared between all pairs of 4 groups. Of these, 464 candidate genes were differentially expressed between cross-phenotype groups, but not for between same-phenotype groups. Gene Ontology (GO) annotation showed that 390 candidate genes were annotated with 2234 GO terms. No candidate genes were directly involved in biosynthesis or transport of biliverdin. However, the integral components of membrane, metal ion transport, cholesterol biosynthesis, signal transduction, skeletal system development, and chemotaxis were significantly (P

The dopamine transporter (DAT) serves a critical role in controlling dopamine (DA)-mediated neurotransmission by regulating the clearance of DA from the synapse and extrasynaptic regions and thereby modulating DA action at postsynaptic DA receptors. Major drugs of abuse such as amphetamine and cocaine interact with DATs to alter their actions resulting in an enhancement in extracellular DA concentrations. We previously identified a novel allosteric site in the DAT and the related human serotonin transporter that lies outside the central orthosteric substrate- and cocaine-binding pocket. Here, we demonstrate that the dopaminergic psychostimulant sydnocarb is a ligand of this novel allosteric site. We identified the molecular determinants of the interaction between sydnocarb and DAT at the allosteric site using molecular dynamics simulations. Biochemical-substituted cysteine scanning accessibility experiments have supported the computational predictions by demonstrating the occurrence of specific interactions between sydnocarb and amino acids within the allosteric site. Functional dopamine uptake studies have further shown that sydnocarb is a noncompetitive inhibitor of DAT in accord with the involvement of a site different from the orthosteric site in binding this psychostimulant. Finally, DA uptake studies also demonstrate that sydnocarb affects the interaction of DAT with both cocaine and amphetamine. In summary, these studies further strengthen the prospect that allosteric modulation of DAT activity could have therapeutic potential.

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The article reveals the essence of the concept of “diagnosis of the enterprise transport activity”, by which there should be meant a process of evaluating the state of movement (transportation, carrying) of freight (material resources, work in process or finished products) by one type of transport facilities or their combination in accordance with the applied transport system and trends of its changes as well as determining the future prospects on the basis of sound management decisions in order to ensure a successful operation and development of the enterprise in the competitive environment. It has been found that the key business-indicators of the diagnosis system of transport activity as a component of the enterprise logistical system are: the coefficient of timeliness of freight transportation (delivery); coefficient of completeness of transportation; coefficient of freight safety conditions; coefficient of efficiency of freight transportation; coefficient of complexity of servicing freight owners; coefficient of satisfaction of freight owners’ demand, coefficient of readiness to operation of transport facilities per working day; coefficient of using vehicle kilometers travelled; coefficient of extensity of transport facility packing.

Platelets have been reported to exert diverse actions besides hemostasis and thrombus formation in the body. However, whether platelets affect transporter activity remains to be determined. In this study, we examined the effects of platelets on the activity of amino acid transporter system A, which is known to be changed by various factors, and we clarified the mechanism by which platelets affect system A activity. Among system A subtypes, we found that sodium-coupled neutral amino acid transporter (SNAT) 4 played a central role in the transport activity of system A in HuH-7 human hepatoma cells. Interestingly, platelets showed a biphasic effect on system A activity: activated platelet supernatants (APS) including the granule contents released from platelets downregulated system A activity at lower concentrations and the downregulation was suppressed at higher concentrations. The downregulation was due to a decrease in the affinity of SNAT4 for its substrate and not a decrease in the SNAT4 abundance on the plasma membrane. In addition, APS did not decrease the expression level of SNAT4 mRNA. On the other hand, platelets did not affect system A activity when the platelet suspension was added to HuH-7 cells. These results indicate that platelets indirectly affect the transport activity of system A by releasing bioactive substances but do not directly affect it by binding to HuH-7 cells.

Phenols are the most abundant naturally accessible antioxidants present in a human normal diet. Since numerous beneficial applications of phenols as preventive agents in various diseases were revealed, the evaluation of phenols bioavailability is of high interest of researchers, consumers and drug manufacturers. The hydrophilic nature of phenols makes a cell membrane penetration difficult, which imply an alternative way of uptake via membrane transporters. However, the structural and functional data of membrane transporters are limited, thus the in silico modelling is really challenging and urgent tool in elucidation of transporter ligands. Focus of this research was a particular transporter bilitranslocase (BTL). BTL has a broad tissue expression (vascular endothelium, absorptive and excretory epithelia) and can transport wide variety of poly-aromatic compounds. With available BTL data (pKi [mmol/L] for 120 organic compounds) a robust and reliable QSAR models for BTL transport activity were developed and extrapolated on 300 phenolic compounds. For all compounds the transporter profiles were assessed and results show that dietary phenols and some drug candidates are likely to interact with BTL. Moreover, synopsis of predictions from BTL models and hits/predictions of 20 transporters from Metrabase and Chembench platforms were revealed. With such joint transporter analyses a new insights for elucidation of BTL functional role were acquired. Regarding limitation of models for virtual profiling of transporter interactions the computational approach reported in this study could be applied for further development of reliable in silico models for any transporter, if in vitro experimental data are available.

This research analyzes the importance of population, economic activity, transport volume and structural characteristics of transport activity—in terms of transport energy intensity, of transport modes' share and of energy sources’ mix—as driving factors of greenhouse gas emissions in transport activity in the EU-28 during the period 1990–2014. The analysis is based on the STIRPAT model, which is broadened to investigate in depth the impact on transport emissions of changes in the transport activity and in the whole economy. Using panel data econometric techniques, the significance of each factor and the impact of its change on emissions are identified. A better knowledge of the key driving forces is crucial for implementing policies focused on successfully reducing emissions in transport activity. The results allow a preliminary assessment of the potential effectiveness of the 2011 Transport White Paper measures aimed at cutting transport emissions. [ABSTRACT FROM AUTHOR]

The intestinal peptide transporter 1 (PepT1) was first identified in 1994. It plays a crucial role in the absorption of small peptides including not only >400 different dipeptides and 8,000 tripeptides digested from dietary proteins but also a repertoire of structurally related compounds and drugs. Owing to its critical role in the bioavailability of peptide-like drugs, such as the anti-cancer agents and anti-virus drug, PepT1 is increasingly becoming a striking prodrug-designing target. Therefore, the understanding of PepT1 gene regulation is of great importance both for dietary adaptation and for clinical drug treatment. After decades of research, it has been recognized that PepT1 could be regulated at the transcriptional and post-transcriptional levels by numerous factors. Therefore, the present review intends to summarize the progress made in the regulation of PepT1 and provide insights into the PepT1's potential in clinical aspects of nutritional and drug therapies. [ABSTRACT FROM AUTHOR]

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