Transport Pool Research Articles

A glucomannan produced by Bacillus velezensis HY23 and its growth promoting effect on soybeans under salt stress

The Bacillus genus is widely distributed in nature, has bacteriostatic and growth-promoting activities, and has broad application potential in agriculture. An exopolysaccharide (EPS) was extracted and purified from Bacillus velezensis HY23. Structural characterisation of the EPS was performed by chemical and spectroscopic analyses. Methylation analysis showed that the EPS of HY23 was composed of mannose and glucose at a ratio of 82:18 and was identified as glucomannan. Combined with the nuclear magnetic resonance (NMR) analysis, EPS from HY23 had a backbone of →2)-α-D-Manp-(1 → and →2,6)-α-D-Manp-(1 → branched at C-6 with terminal α-(3-O-Me)-D-Manp-(1 → and →6)-α-D-Manp-(1 → residues as the side chain. A certain amount of β-D-Glcp residues were also present in backbone. Moreover, EPS significantly improved the nitrogen-fixing activity and salt resistance of soybean seedlings by regulating the antioxidant pool and expression of ion transporters. These findings indicate that EPS from B. velezensis HY23 is a potential biostimulant for enhancing plant resistance to salt stress.

Hydrochorous Seed Transport in the Lower Traisen River before and after Riverbed Restoration.

Hydrological restoration was carried out in a Lower Traisen, a small river within the floodplain of the Danube. The main goal was the reestablishment of typical riparian plant communities by using the potential of natural dispersal processes. We studied the transport of plant diaspores in the river water before and after the reconstruction of the riverbed. Aquatic seed traps were placed upstream and downstream of the restoration site. We identified the transported species and tested the viability of propagules. Functional species traits were analyzed to predict the probability of successful hydrochorous dispersal and changes in the transport pool due to the restoration. One-third of the local species pool was detected as being diaspores in the river. We observed a significant increase of ruderal species and neophytes, while the competitors and stress-tolerant competitors declined. Hydrochory is an important dispersal pathway for numerous plant species in the study area, including those without specific adaptations to this vector. Hydrochorous transport appears to be a sink for large-seeded species, primarily adapted to endozoochory. Follow-up management should be recommended to control the invasive species and to improve the structural and biological diversity of the Traisen Valley by supporting target species, which are also represented in the transport pool.

Interplay of ZnONPs and/or SeNPs induces arsenic tolerance in soybean by regulation of antioxidants pool, WRKY genes, and expression of arsenic transporters

Arsenic is a nonessential element that confers toxicity to plants. Excessive arsenic accumulation in food crops poses safety concerns for human and animal health. To date, our understanding of the alleviation mechanism of As(V) toxicity in soybean plant employing NP is less known. Thus, the objective of the present study was to evaluate the effectiveness of zinc oxid nanoparticle (ZnONP) and/or selenium nanoparticle (SeNP) treatment on arsenic stress in seedling of soybean (Glycine max [L] Merrill). Soybean seedlings were grown hydroponically in 10 liters pots, treated at V2 growth stage with arsenate (25 μM L−1), two concentrations of ZnONPs (25 μM and 50 μM L−1) and two concentrations of elemental SeNPs (10 μM and 25 μM L−1) separately and in tandem, and then kept for further 10 d. Positive control (T2) significantly induced electrolyte leakage (EL) and facilitated the accumulation of O2− and H2O2 in roots and leaf tissues, along with higher deposition of As in sensitive cell organs including cellular organelles and cell wall. The application of ZnONPs and SeNPs, both independently and in tandem, promoted the As compartmentalization into vacuole, reduced the EL and rescued plant health by enhanced the metal tolerance index (MTI). In addition, cellular toxicants (i.e., O2−, H2O2 and GSSG) were drastically reduced because of the steady increased in MDHAR, GSTs, GSH and PCs levels in response to the nanoparticles treatment than in positive control (T2). Moreover, Na+ K+ -ATPase and Ca++ Mg++ -ATPase activities were also induced in response to NPs treatment groups. All the nanoparticles treatment groups displayed elevated expression of TFs (GmWRKY6, GmWRKY46, GmWRKY56, and GmWRKY106) particularly under 50 μM L−1 ZnONPs + 10 μM L−1 SeNPs (T8) compared to both negative (T1) and positive control (T2). More importantly, application of nanoparticles, both either independently or in tandem, decreased the expression of GmPT1, GmPT2, GmPT3, GmPT4 and GmPT8 with an exception of GmPT2 under SeNPs treatment group. Thus, the concurrent application of ZnONPs + SeNPs can be considered as eco-friendly fertilizer that will mimic As(V) toxicity and improve the growth and yield of soybean plants in As polluted areas.

Hydrochorous seed transport in a small river in Northern Germany as trait‐dependent filter of plant dispersal and recruitment

AbstractWe studied seed transport in the Upper Eider River (Northern Germany). Our main questions were: Diaspores of what species are transported in the river and which of them remain viable after the drift? Could functional species traits be used as predictors for the survival of plant propagules in course of water transport? The water body of the Upper Eider River was sampled for plant diaspores at two bridges with each four traps changed weekly during the whole year. Samples were separated into two equal groups. Each two samples per bridge and week were dried and seeds were counted manually. The other two samples were spread on sterilised soil for germination. Species composition and community weighted trait means were compared for dried samples (total transport) and seedlings (germinated after drift). About half of the species and 1/10 of the seeds were able to survive hydrochorous transport. Species traits (community weighted means) were not reliable predictors for survival of species during the hydrochorous transport, but the majority of traits reflect the differences between the transport pools of seeds and seedlings. Small seed size, ruderal life strategy, and high light preference correlate positively with germinability after the drift, while large‐seeded species adapted to endozoochory tend to lose viability during hydrochory. Dispersal of terrestrial plants with running water in the studied small river system is a highly stochastic event. We did not find evidence that specific adaptations to hydrochory significantly contribute to its success. Nevertheless, a few functional traits can increase the probability for the species to pass through the ecological filter “hydrochory.” Among those traits are (i) small seed size (less vulnerability for mechanical stress), (ii) generalist dispersal mode, less dependent on other particular vectors, and (iii) ruderal life strategy.

Pharmacological evidence for the concept of spare glutamate transporters

Through the efficient clearance of extracellular glutamate, high affinity astrocytic glutamate transporters constantly shape excitatory neurotransmission in terms of duration and spreading. Even though the glutamate transporter GLT-1 (also known as EAAT2/SLC1A2) is amongst the most abundant proteins in the mammalian brain, its density and activity are tightly regulated. In order to study the influence of changes in the expression of GLT-1 on glutamate uptake capacity, we have developed a model in HEK cells where the density of the transporter can be manipulated thanks to a tetracycline-inducible promoter. Exposing the cells to doxycycline concentration-dependently increased GLT-1 expression and substrate uptake velocity. However, beyond a certain level of induction, increasing the density of transporters at the cell surface failed to increase the maximal uptake. This suggested the progressive generation of a pool of spare transporters, a hypothesis that was further validated using the selective GLT-1 blocker WAY-213613 of which potency was influenced by the density of the transporters. The curve showing inhibition of uptake by increasing concentrations of WAY-213613 was indeed progressively rightward shifted when tested in cells where the transporter density was robustly induced. As largely documented in the context of cell-surface receptors, the existence of ‘spare’ glutamate transporters in the nervous tissue and particularly in astrocytes could impact on the consequences of physiological or pathological regulation of these transporters.

Regulation of Glutamate, GABA and Dopamine Transporter Uptake, Surface Mobility and Expression.

Neurotransmitter transporters limit spillover between synapses and maintain the extracellular neurotransmitter concentration at low yet physiologically meaningful levels. They also exert a key role in providing precursors for neurotransmitter biosynthesis. In many cases, neurons and astrocytes contain a large intracellular pool of transporters that can be redistributed and stabilized in the plasma membrane following activation of different signaling pathways. This means that the uptake capacity of the brain neuropil for different neurotransmitters can be dynamically regulated over the course of minutes, as an indirect consequence of changes in neuronal activity, blood flow, cell-to-cell interactions, etc. Here we discuss recent advances in the mechanisms that control the cell membrane trafficking and biophysical properties of transporters for the excitatory, inhibitory and modulatory neurotransmitters glutamate, GABA, and dopamine.

Fractionation analysis of the subcellular distribution of GLUT-4 in 3T3-L1 adipocytes.

AbstractIn 1980, two groups simultaneously provided evidence of the existence of an intracellular pool of glucose transporters in rat adipocytes (1,2). We now know that facilitative glucose uptake occurs through a family of highly related integral membrane proteins that share significant sequence similarity. Of the established glucose transporter isoforms, GLUT-4 is highly expressed in adipose tissue and striated muscle (3). In the basal state, GLUT-4 cycles slowly between the plasma membrane and one or more intracellular compartments, with the vast majority of the transporter residing in vesicular compartments within the cell interior (4–6). Activation of the insulin receptor triggers a large increase in the rate of GLUT-4 vesicle exocytosis and a smaller decrease in the rate of internalization by endocytosis (7–10). The stimulation of exocytosis by insulin is probably the major step for GLUT-4 translocation because complete inhibition of GLUT-4 endocytosis only modestly increases plasma membrane-associated GLUT-4 protein without affecting the extent of insulin-stimulated GLUT-4 translocation (11–13). In contrast to GLUT-4, GLUT-1 is an intracellular and plasma membrane localized in the basal state and displays a modest insulin-stimulated redistribution to the plasma membrane. Thus, the overall insulin-dependent shift in the cellular dynamics of GLUT-4 vesicle trafficking results in a net increase of GLUT-4 on the cell surface, thereby increasing the rate of glucose uptake.KeywordsSucrose CushionPyridoxine HydrochlorideVesicular CompartmentAdipocyte DevelopmentJA20 RotorThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

β-catenin is important for the development of an insulin responsive pool of GLUT4 glucose transporters in 3T3-L1 adipocytes

GLUT4 is unique among specialized glucose transporters in being exclusively expressed in muscle and adipocytes. In the absence of insulin the distribution of GLUT4 is preferentially intracellular and insulin stimulation results in the movement of GLUT4 containing vesicles to the plasma membrane. This process is responsible for the insulin stimulation of glucose uptake in muscle and fat. While signalling pathways triggering the translocation of GLUT4 are well understood, the mechanisms regulating the intracellular retention of GLUT4 are less well understood. Here we report a role for β-catenin in this process. In 3T3-L1 adipocytes in which β-catenin is depleted, the levels of GLUT4 at and near the plasma membrane rise in unstimulated cells while the subsequent increase in GLUT4 at the plasma membrane upon insulin stimulation is reduced. Small molecule approaches to acutely activate or inhibit β-catenin give results that support the results obtained with siRNA and these changes are accompanied by matching changes in glucose transport into these cells. Together these results indicate that β-catenin is a previously unrecognized regulator of the mechanisms that control the insulin sensitive pool of GLUT4 transporters inside these adipocyte cells.

Cinnamon effectively inhibits the activity of leukemia stem cells.

Cinnamon is the main component of Sanyangxuedai, which is one of the effective traditional Chinese medicines for treating malignancies. Leukemia is a prevalent malignant disease that Sanyangxuedai has been used to treat. Although successful in several studies, there is a lack of solid evidence as to why Sanyangxuedai has an effect on leukemia, and little is known about the underlying mechanisms. In this study, the active ingredients of cinnamon were isolated, purified, and identified. The transwell transport pool formed with the Caco-2 cell model was used to filter the active ingredients of cinnamon by simulating the gastrointestinal barrier in vitro. Moreover, the cell morphology, cell cycle status, apoptosis status, and antigenic variation of the cell surface antigens were observed and measured in K562 cells after treatment with the active ingredients of cinnamon. Our results showed that 50-75 μM was a safe concentration of cinnamon extract for treatment of K562 cells for 72 h. The cinnamon extract caused growth inhibition of K562 cells. Cinnamon extract seemed to arrest the cells at the G1 stage and increased the apoptosis rate significantly. Interestingly, cinnamon extract treatment upregulated the expression of erythroid and myeloid differentiation antigens and downregulated that of the megakaryocytic differentiation antigens in a dose-dependent manner. Our findings indicate that cinnamon extract from Sanyangxuedai may be effective for treating leukemia.

The excitatory amino acid carrier 1 (EAAC1) in the rat nucleus of the solitary tract: subcellular localization suggests no major role in glutamate clearance.

The excitatory amino acid carrier 1 (EAAC1) is a sodium-dependent glutamate transporter widely found in the mammalian brain and mainly localized in the somatodendritic compartment of neurons. The present study was performed to determine whether EAAC1 is present in the rat nucleus of the solitary tract (NST, a sensory brainstem nucleus involved in visceroception) and to document its subcellular localization. Using fluorescent immunolabeling, peroxidase immunostaining and quantitative immunogold labeling, we showed that both intracellular and plasma membrane-associated pools of EAAC1 transporters existed in dendrites of NST neurons. Although plasma membrane-associated transporters were more concentrated in the vicinity of synapses, no labeling was found at the axon-dendrite interface, suggesting that EAAC1 was not (or barely) expressed in this portion of dendritic membrane. Using computer simulation, we next showed that the ability of EAAC1 to efficiently take up synaptically released glutamate was very low outside the axon-dendrite interface. These data suggest that EAAC1 transporters present on NST dendrites may play a minor role if any in glutamate clearance.

Alzheimer’s disease: A gas model. The NADPH oxidase–Nitric Oxide system as an antibubble biomachinery

Alzheimer’s disease (AD) is a neurodegenerative disease of unknown origin. The pathological lesions that define AD would be linked to the insidious accumulation of nitrogen, having invaded the brain interstitial fluid (ISF) from the blood via the physiological cycling pool of vascular glucose transporters (GLUT-1). According to this hypothesis, the nitrogen nanobubbles, being chemically inert and actually indestructible for human beings, can not escape from the ISF anymore. They would exert a huge and deleterious pressure against cellular components, especially in microglia and in astrocytes. They could enhance the existing cell oxygen anisotropy, which might enhance the natural bubble nucleation of O2-2O2 in cells or in mitochondria. Indeed, with the help of a new symbolic representation for gas nuclei in chemical reactions, the NADPH oxidase–NO system is identified for the first time, as an antibubble biomachinery, able to break O2-2O2 bubbles up as it releases superoxide O2-. Superoxide is considered as a quantum bubble, which collapses through the reactivity of the gaseous NO radical. Their combination in soluble peroxinitrite provides the change from one state of matter to another, avoiding any risk of a bubble enlargement, and finally avoiding the risk of enzyme crowding or of a bulk pressure variation. However, a bubble is expected to entrap Nitric Oxide (NO), which leads theoretically to a decrease in its bioavailability, and is expected to trigger a guanylyl-cyclase-mediated inflammatory cascade, that could explain the inflammation in AD. In vitro, any increase in the hydrostatic pressure has already been linked to the microtubule disorganization. The amyloid deposits, also known as senile plaques, would behave as a sponge toward ISF nitrogen; Aβ is considered as a foam-stabilizing agent. By taking the shape of cerebral amyloid angiopathy, the amyloid could confine the nitrogen leak from the blood, and progressively insulate the Blood–Brain Barrier against the pollutant. All these theoretical features finally lead to the death of the neurons.The comprehensive statement of the theoretical pro-inflammatory action of inert gases is a real upheaval for the whole medicine.

Heuristic Algorithms for Constructing Transporter Pools in Container Terminals

In port container terminals, containers are transported between vessels and storage blocks by transporters. To improve the utilization of transporters and the operational efficiency of container terminals, the pooling strategy is widely applied, and transporters in the same pool are shared by a group of quay cranes (QCs). This paper compares various strategies for constructing the pools: one pool for each QC, one pool for all the QCs deployed to each vessel, one pool for all the QCs for multiple adjacent vessels, and one pool for all the operating QCs in the terminal. Various heuristic algorithms (HAs) to construct pools of transporters are suggested and evaluated in terms of the total delay time of QC operation and the total travel distance of transporters. In addition, opportunities for dual-command-cycle operation are analyzed for each of these heuristic rules by using different data sets of QC operations. Various scenarios of QC operation are generated, and the HAs are compared in terms of their performance through a simulation study.

Effects of K+-deficient diets with and without NaCl supplementation on Na+, K+, and H2O transporters' abundance along the nephron

Dietary potassium (K(+)) restriction and hypokalemia have been reported to change the abundance of most renal Na(+) and K(+) transporters and aquaporin-2 isoform, but results have not been consistent. The aim of this study was to reexamine Na(+), K(+) and H(2)O transporters' pool size regulation in response to removing K(+) from a diet containing 0.74% NaCl, as well as from a diet containing 2% NaCl (as found in American diets) to blunt reducing total diet electrolytes. Sprague-Dawley rats (n = 5-6) were fed for 6 days with one of these diets: 2% KCl, 0.74% NaCl (2K1Na, control chow) compared with 0.03% KCl, 0.74% NaCl (0K1Na); or 2% KCl, 2%NaCl (2K2Na) compared with 0.03% KCl, 2% NaCl (0K2Na, Na(+) replete). In both 0K1Na and 0K2Na there were significant decreases in: 1) plasma [K(+)] (<2.5 mM); 2) urinary K(+) excretion (<5% of control); 3) urine osmolality and plasma [aldosterone], as well as 4) an increase in urine volume and medullary hypertrophy. The 0K2Na group had the lowest [aldosterone] (172.0 ± 17.4 pg/ml) and lower blood pressure (93.2 ± 4.9 vs. 112.0 ± 3.1 mmHg in 2K2Na). Transporter pool size regulation was determined by quantitative immunoblotting of renal cortex and medulla homogenates. The only differences measured in both 0K1Na and 0K2Na groups were a 20-30% decrease in cortical β-ENaC, 30-40% increases in kidney-specific Ste20/SPS1-related proline/alanine-rich kinase, and a 40% increase in medullary sodium pump abundance. The following proteins were not significantly changed in both the 0 K groups: Na(+)/H(+) exchanger isoform 3; Na(+)-K(+)-Cl(-) cotransporter; Na(+)-Cl(-) cotransporter, oxidative stress response kinase-1; renal outer medullary K(+) channel; autosomal recessive hypercholesterolemia; c-Src, aquaporin 2 isoform; or renin. Thus, despite profound hypokalemia and renal K(+) conservation, we did not confirm many of the changes that were previously reported. We predict that changes in transporter distribution and activity are likely more important for conserving K(+) than changes in total abundance.

A Lift Assist Team in an Acute Care Hospital—Prevention of Injury or Transfer of Risk During Patient-Handling Tasks?

A Lift Assist Team (LAT) was created on three units at a medical center where nursing staff were at high risk for patient-handling injuries. LAT members were drawn from the hospital's pool of patient transporters. Using qualitative and quantitative data, this case study summarizes the development, implementation, and experiences of the LAT. Nursing staff valued the LAT, reporting increased staff safety and improved patient care. LAT members reported greater job satisfaction and a newfound sense of assimilation into the nursing group compared to when their role was patient transport only. However, over time, their job responsibilities expanded beyond those officially designated for LAT members. Active, ongoing surveillance of the LAT's exposures and outcomes is warranted to understand whether patient-handling injury risk is shifting from nursing personnel to LAT members.

A Lift Assist Team in an Acute Care Hospital— Prevention of Injury or Transfer of Risk during Patient-Handling Tasks?

A Lift Assist Team (LAT) was created on three units at a medical center where nursing staff were at high risk for patient-handling injuries. LAT members were drawn from the hospital's pool of patient transporters. Using qualitative and quantitative data, this case study summarizes the development, implementation, and experiences of the LAT. Nursing staff valued the LAT, reporting increased staff safety and improved patient care. LAT members reported greater job satisfaction and a newfound sense of assimilation into the nursing group compared to when their role was patient transport only. However, over time, their job responsibilities expanded beyond those officially designated for LAT members. Active, ongoing surveillance of the LAT's exposures and outcomes is warranted to understand whether patient-handling injury risk is shifting from nursing personnel to LAT members.

Breast Imaging Review: A Quick Guide to Essential Diagnoses

327 Objectives Acute intravascular thrombosis is associated with focal increased uptake of FDG on PET and may provide a surrogate of early molecular events in the thrombotic cascade. Thrombi are rich in platelets, but also in neutrophils and monocytes. The objective was to characterize 2-deoxyglucose uptake by thrombotic activation of these cells. Methods Human neutrophils, platelets and monocytes were isolated and thrombotically activated by platelet activating factor (PAF), thrombin and lipopolysaccharide (LPS), respectively. The effect of activation on uptake of D-glucose analogs (fluorescent NBDG, 18F-FDG, 14C-2DG) was measured by gamma well counting, liquid scintillation counting, confocal microscopy, or flow cytometry. Activation-induced expression and localization of GLUT transporters and hexokinase (HK) was established by real-time PCR, or immunostaining with Western Blot analysis, confocal microscopy, or flow cytometry. Results PAF activation of neutrophils results in rapid 3-4 fold increase in uptake of D-glucose analogs, associated with increases in expression of GLUT-1, GLUT-3, GLUT-4, HK1, HK3, and small increases in GLUT-5 and 6. Thrombin activation of platelets results in a very rapid 3 fold increase in uptake of D-glucose analogs, and a 4-6 fold increase in membrane-associated GLUT-3 expression, likely by rapid externalization of an internal pool of transporter. LPS stimulation of monocytes produces only a minimal (10-30%) increase in glucose uptake, with a slight increase in GLUT-1 expression only. Conclusions Thrombogenic activation of platelets and neutrophils results in significant increased uptake of D-glucose analogs, associated with increased expression of GLUT-1, GLUT-3, GLUT-4, HK1, and HK 3, and externalization of an internal pool of GLUT-3 transporters by platelets. Stimulated monocytes show minimal increased uptake of D-glucose analogs. FDG PET may provide an imaging surrogate of early molecular events associated with thrombogenesis, and a mechanism for early assessment of antithrombotic therapies. Research Support NIH/NCI R01CA121003-01A

The glutamate transporter excitatory amino acid carrier 1 associates with the actin-binding protein α-adducin

Excitatory amino acid carrier 1 (EAAC1) belongs to the family of the Na +-dependent glutamate carriers. Although the association between defective EAAC1 function and neurologic disease has been repeatedly studied, EAAC1 regulation is not yet fully understood. We have reported that in C6 glioma cells both the activity and membrane targeting of EAAC1 require the integrity of actin cytoskeleton. Here we show that, in the same model, EAAC1 partially co-localizes with actin filaments at the level of cell processes. Moreover, perinuclear spots in which EAAC1 co-localizes with the actin binding protein α-adducin are observed in some cells and, consistently, faint co-immunoprecipitation bands between EAAC1 and α-adducin are detected. Co-localization and partial co-immunoprecipitation of EAAC1 and adducin are still detectable after cell treatment with phorbol esters, a condition that leads to a protein kinase C (PKC)-dependent increase of EAAC1 expression on the membrane and to the phosphorylation of adducin. A co-immunoprecipitation band was also detected in protein extracts of rat hippocampus. The amount of adducin co-immunoprecipitated with EAAC1 increases after the treatment of C6 cells with retinoic acid, a differentiating agent that induces EAAC1 overexpression in this cell model. Moreover, in clones of C6 cells transfected with a hemagglutinin (HA)-tagged adducin, the bands of EAAC1 immunoprecipitated by an anti-HA antiserum were proportional to EAAC1 expression. These results suggest the existence of a pool of EAAC1 transporters associated with the actin binding protein α-adducin in a PKC-insensitive manner.

Visualization of Dopamine Transporter Trafficking in Live Neurons by Use of Fluorescent Cocaine Analogs

The dopamine transporter (DAT) mediates reuptake of dopamine from the synaptic cleft and is a target for widely abused psychostimulants such as cocaine and amphetamine. Nonetheless, little is known about the cellular distribution and trafficking of natively expressed DAT. Here we use novel fluorescently tagged cocaine analogs to visualize DAT and DAT trafficking in cultured live midbrain dopaminergic neurons. The fluorescent tags were extended from the tropane N-position of 2beta-carbomethoxy-3beta-(3,4-dichlorophenyl)tropane using an ethylamino-linker. The rhodamine-, OR Green-, or Cy3-labeled ligands had high binding affinity for DAT and enabled specific labeling of DAT in live neurons and visualization by confocal imaging. In the dopaminergic neurons, DAT was uniformly distributed in the plasma membrane of the soma, the neuronal extensions, and varicosities along these extensions. FRAP (fluorescence recovery after photobleaching) experiments demonstrated bidirectional movement of DAT in the extensions and indicated that DAT is highly mobile both in the extensions and in the varicosities (immobile fraction less than approximately 30%). DAT was constitutively internalized into vesicular structures likely representing intracellular transporter pools. The internalization was blocked by lentiviral-mediated expression of dominant-negative dynamin and internalized DAT displayed partial colocalization with the early endosomal marker EGFP-Rab5 and with the transferrin receptor. DAT internalization and function was not affected by activation of protein kinase C (PKC) with phorbol-12-myristate-13-acetate (PMA) or by inhibition with staurosporine or GF109203X. These data are in contrast to findings for DAT in transfected heterologous cells and challenge the paradigm that trafficking and cellular distribution of endogenous DAT is subject to regulation by PKC.

Climate effects on the nitrogen balance of beech (Fagus sylvatica) at its south‐eastern distribution limit in Europe

Owing to its wide European distribution and drought sensitivity, beech (Fagus sylvatica L.) has captured the attention of researchers in the context of climate change. Contrary to central European beech ecosystems, little is known about the nitrogen (N) balance of beech at its south‐eastern European distribution limit. Here we studied the seasonal variation of key N‐related parameters during the period 2003–2004, and tested whether climatic differences between the years affected the N balance of beech in north‐western Greece. The warmer and drier climate of 2003 was characterised by lower soil N availability, compared to 2004. The pool of total soluble non‐protein nitrogen (TSNN) was more sensitive than total N to interannual differences in growth conditions, as reflected particularly in the TSNN concentrations, and in the composition of phloem and xylem sap in early spring. In 2003, the N demands of expanding leaves were covered mainly by stored N remobilisation, as indicated by elevated TSNN levels in phloem and xylem sap, and by increased loading of arginine and glutamine, major N‐storage compounds, in these N‐exchange and transport pools. By contrast, the more favourable growth conditions of 2004 supported new growth also by current root N uptake, as indicated by increased asparagine levels in phloem and xylem sap.

Streamlining the Preoperative Holding Process to Increase Efficiency and Satisfaction

Preoperative holding of patients can be challenging. The physical arrangement (PODS) of our department was designed for patient privacy but not efficient for surgeons, anesthesia or the nursing staff. The OR schedule is reviewed the previous day by the charge nurse for patient census, isolation patients, special needs patients, transport pool needs and staffing. Operating rooms are then assigned to certain PODS. A master white board was installed. POD numbers, OR room letters and physician names are written on the board. In each POD a smaller white board with POD room number, OR room and time, and physician name was designed. This board also includes other needs before the patient goes to the OR such as consent, site, glasses, dentures etc. This practice has eliminated multiple phone calls to the holding desk. It allows surgeons, anesthesia and the OR staff to locate the patient easily. As perianesthesia nurses, we took a proactive approach to establish a process that worked well for our department to meet the needs of the entire perioperative team.