Membrane transport activity and ultradian ion flux oscillations associated with cell cycle of Thraustochytrium sp.

2001 ◽  
Vol 28 (2) ◽  
pp. 87 ◽  
Author(s):  
Lana Shabala ◽  
Sergey Shabala ◽  
Tom Ross ◽  
Tom McMeekin
Keyword(s):  
Nutritional Status ◽  
Membrane Transport ◽  
Close Association ◽  
Essential Element ◽  
Ion Flux ◽  
Transport Activity ◽  
Period Range ◽  
Bathing Medium ◽  
Zoospore Release ◽  
Cross Correlation Analysis

Membrane transport activity associated with growth and nutritional status of a marine microheterotroph Thraustochytrium sp. was studied using non-invasive ion-selective slowly vibrating microelectrodes (the MIFE technique). Net fluxes of H + , Ca 2+ and Na + underwent regular changes as the cell progressed from the zoospore to sporangium stages of development. The most pronounced change was a decrease in the net H + influx, which we suggest could be associated with the changes in cytoskeletal organization required for cell cleavage and zoospore release. As cell development progressed from the zoospore stage towards maturity, non-damping endogenous ultradian oscillations (period range of several minutes) became evident. At the sporangium stage, as many as 85% of cells possessed oscillatory membrane transport activity. It is suggested that ultradian ion flux oscillations in Thraustochytrium sp. may be causally linked with cell developmental processes. Discrete Fourier transform and cross-correlation analysis revealed a close association between oscillatory patterns of H + and Na + fluxes. The possibility that these oscillations result from the rhythmical activity of a Na + /H + co-transporter located at the plasma membrane of Thraustochytrium sp. is considered. Oscillations in net Ca 2+ flux were apparently not linked to those in H+ and Na + , and are believed to be due to some other physiological processes. Periods of net H + and Na + flux oscillations were strongly dependent on the external Na + concentrations in the bathing medium. As sodium is considered to be an essential element in Thraustochytrium sp., it is suggested that the functional role of such ultradian oscillations may be their involvement in the frequency-encoding mechanism that provides developing cells with information about environment, and nutritional status in particular.

Ysis Prescription and Peritoneal Membrane Transport Characteristics on Nutritional Status

1995 ◽  
Vol 15 (5_suppl) ◽  
pp. 20-37 ◽  
Author(s):  
John M. Burkart
Keyword(s):  
Nutritional Status ◽  
Membrane Transport ◽  
Peritoneal Membrane ◽  
Dialysis Dose ◽  
Irreversible Damage ◽  
Histological Changes ◽  
Unique Challenge ◽  
Long Time ◽  
The Individual ◽  
Higher Doses

These data suggest that dialysis dose is one of the major determinants of protein and energy intake in PD patients and that higher doses of dialysis tend to improve outcome. The data also suggest that with a long time on PD the peritoneal membrane probably has some underlying histological changes that preclude it from optimally responding to injury and may predispose it to irreversible damage. A possible early finding in this case is an increase in peritoneal transport in patients whose transport was initially stable. Peritoneal membrane transport properties are an important determinant of not only dialysis dose, but also nutritional status via both direct and indirect means. It is therefore important to identify the individual patient's peritoneal membrane transport characteristics. These transport characteristics may change over time. High transporters on CAPD represent a unique challenge. They have ultrafiltration problems and a tendency toward protein malnutrition presumably due to increased dialysate protein losses while on CAPD. One must consider that malnutrition in a rapid transporter may be due to the fact that the patient is on the wrong PD therapy. A change to NIPD may rectify some of the biochemical parameters, but these patients may not always improve. Reasons for this occasional lack of improvement are multifactorial, but emphasize our need to look at each patient as an individual and not focus only on laboratory parameters.

Specific transporter for iron(III): Phytosiderophore complex involved in iron uptake by barley roots

2008 ◽  
Vol 80 (12) ◽  
pp. 2689-2697 ◽  
Author(s):  
Yoshiko Murata ◽  
Emiko Harada ◽  
Kenji Sugase ◽  
Kosuke Namba ◽  
Manabu Horikawa ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Iron Uptake ◽  
Essential Element ◽  
Synthetic Method ◽  
Uptake System ◽  
Transport Activity ◽  
Biological Studies ◽  
Specific Uptake ◽  
Transmembrane Regions ◽  
Distinct Strategy

Iron (Fe) is an essential element for plant growth. Gramineous plants have generally developed a distinct strategy to efficiently acquire insoluble Fe, which is characterized by the synthesis and secretion of an Fe-chelating substance, phytosiderophore (PS) such as mugineic acid (MA), and by a specific uptake system for Fe(III)-PS complexes. In a previous study, we identified a gene specifically encoding an Fe(III)-PS transporter (HvYS1) in barley. This gene as well as the encoded protein is specifically expressed in the epidermal cells of the roots, and gene expression is greatly enhanced under Fe-deficient conditions. The localization and substrate specificity of HvYS1 indicate that it is a specific transporter in barley roots. In contrast, ZmYS1, which has been reported as an Fe-PS transporter from maize, possesses broad substrate specificity despite a high homology with HvYS1. By assessing the transport activity of a series of HvYS1-ZmYS1 chimeras, we revealed that the outer membrane loop between the 6th and 7th transmembrane regions is essential for the substrate specificity. We also achieved an efficient short-step synthesis of MA and 2'-deoxymugineic acid (DMA). Our new synthetic method enabled us to use them in a large quantity for biological studies.

scholarly journals The Haemophilus influenzae hFbpABC Fe3+ Transporter: Analysis of the Membrane Permease and Development of a Gallium-Based Screen for Mutants

2007 ◽  
Vol 189 (14) ◽  
pp. 5130-5141 ◽  
Author(s):  
Damon S. Anderson ◽  
Pratima Adhikari ◽  
Katherine D. Weaver ◽  
Alvin L. Crumbliss ◽  
Timothy A. Mietzner
Keyword(s):  
Haemophilus Influenzae ◽  
Binding Protein ◽  
Essential Element ◽  
Transport Activity ◽  
Sequence Alignments ◽  
Multiple Sequence ◽  
Multiple Sequence Alignments ◽  
Discernible Effect ◽  
Iron Binding Protein ◽  
And Function

ABSTRACT The obligate human pathogen Haemophilus influenzae utilizes a siderophore-independent (free) Fe3+ transport system to obtain this essential element from the host iron-binding protein transferrin. The hFbpABC transporter is a binding protein-dependent ABC transporter that functions to shuttle (free) Fe3+ through the periplasm and across the inner membrane of H. influenzae. This investigation focuses on the structure and function of the hFbpB membrane permease component of the transporter, a protein that has eluded prior characterization. Based on multiple-sequence alignments between permease orthologs, a series of site-directed mutations targeted at residues within the two conserved permease motifs were generated. The hFbpABC transporter was expressed in a siderophore-deficient Escherichia coli background, and effects of mutations were analyzed using growth rescue and radiolabeled 55Fe3+ transport assays. Results demonstrate that mutation of the invariant glycine (G418A) within motif 2 led to attenuated transport activity, while mutation of the invariant glycine (G155A/V/E) within motif 1 had no discernible effect on activity. Individual mutations of well-conserved leucines (L154D and L417D) led to attenuated and null transport activities, respectively. As a complement to site-directed methods, a mutant screen based on resistance to the toxic iron analog gallium, an hFbpABC inhibitor, was devised. The screen led to the identification of several significant hFbpB mutations; V497I, I174F, and S475I led to null transport activities, while S146Y resulted in attenuated activity. Significant residues were mapped to a topological model of the hFbpB permease, and the implications of mutations are discussed in light of structural and functional data from related ABC transporters.

scholarly journals Hydrogen membrane transport activity coupled with changing deuterium/hydrogen ratio may be a key proliferation signal for the cells

2014 ◽  
Vol 5 ◽  
Author(s):  
Somlyai Gábor ◽  
Nagy Lajos ◽  
Puskás László ◽  
Fábián Gabriella ◽  
Gyöngyi Zoltán ◽  
...  
Keyword(s):  
Membrane Transport ◽  
Transport Activity ◽  
Hydrogen Membrane

Observation and Theory of Strain–Infrasound Coupling during Ground-Coupled Infrasound Generated by Rayleigh Waves in the Longitudinal Valley (Taiwan)

2020 ◽  
Vol 110 (6) ◽  
pp. 2991-3003
Author(s):  
Alexandre Canitano
Keyword(s):  
Atmospheric Pressure ◽  
Rayleigh Waves ◽  
Seismic Waves ◽  
Seismic Velocity ◽  
Pressure Fluctuations ◽  
Radial Distance ◽  
Period Range ◽  
Intrinsic Nature ◽  
Strain Waves ◽  
Cross Correlation Analysis

ABSTRACT In this study, changes in atmospheric pressure recorded by absolute microbarometers operating in the Longitudinal Valley (Taiwan) during the passing seismic waves from strong earthquakes (Mw≥6) are systematically analyzed during the 2007–2019 period. Using a continuous wavelet transform analysis, local infrasound signals are detected for 23% of the events (21 events out of 89), with Mw ranging from 6.0 to 9.1 at a radial distance of 15 to about 4000 km from the central Longitudinal Valley. Infrasound signals are observed in the period range from about 1 to 20 s; they have maximal amplitudes ranging from 0.4 to 20 Pa and initiate predominantly during the passage of Rayleigh waves. The atmospheric pressure response to dilatational strain waves during seismoacoustic disturbances is investigated using collocated borehole strainmeter stations, and dynamic interactions between signals are characterized using a sliding windowed time-lagged cross-correlation analysis. The infrasound response shows a phase shift of −60° to −100°, with respect to the dilatation strain signal with a coupling factor of 0.002–0.006  Pa/nϵ for most of the cases (62%). Whereas acoustic pressure fluctuations are generated instantaneously by the vertical seismic velocity, the phase delay is related to the intrinsic nature of the dilatational strain. Observational strain–infrasound coupling parameters are in close agreement with theoretical estimates in the case of ground-coupled acoustic signals generated by Rayleigh waves. The study represents the first attempt to analyze ground-coupled infrasonic waves with strain waves and illustrates the potential of collocated strainmeter–microbarometer stations for basic seismoacoustic studies.

Buckwheat FeNramp5 mediates high Mn uptake in roots

2020 ◽  
Author(s):  
Kengo Yokosho ◽  
Naoki Yamaji ◽  
Jian Feng Ma
Keyword(s):  
Growth And Development ◽  
Essential Element ◽  
Natural Resistance ◽  
Transport Activity ◽  
Plant Growth And Development ◽  
Acidic Soils ◽  
Specific Expression ◽  
Absolute Expression ◽  
Fagopyrum Esculentum Moench ◽  
Absolute Expression Level

Abstract Manganese (Mn) is an essential element for plant growth and development, but transporters required for Mn uptake have only been identified in a few plant species. Here, we functionally characterized a member of natural resistance-associated macrophage proteins (Nramps) family, FeNramp5 in buckwheat (Fagopyrum esculentum Moench), which is known as a species well adapted to acidic soils. FeNramp5 was mainly expressed in the roots and its expression was up-regulated by deficiency of Mn and Fe. Furthermore, spatial and tissue-specific expression analysis showed that FeNramp5 was expressed in all tissues of the basal root regions. FeNramp5-GFP protein was localized to the plasma membrane when transiently expressed in buckwheat leaf protoplast. FeNramp5 showed transport activity for Mn2+ and Cd2+, but not for Fe2+ when expressed in yeast. Furthermore, the transport activity for Mn2+ was higher in yeast expressing FeNramp5 than in yeast expressing AtNramp1. FeNramp5 was also able to complement phenotype of Arabidopsis atnramp1 mutant in terms of growth and accumulation of Mn and Cd. The absolute expression level of AtNramp1 was comparable to that of FeNramp5 in the roots, but buckwheat accumulated higher Mn than Arabidopsis when grown under the same condition. Further analysis showed that at least motif B in FeNramp5 seems important for its high transport activity for Mn. These results indicate that FeNramp5 is a transporter for uptake of Mn and Cd and its higher transport activity for Mn is probably associated with higher Mn accumulation in buckwheat.

The Influence of Glucose Exposure Load and Peritoneal Membrane Transport on Body Composition and Nutritional Status Changes after 1 Year on Peritoneal Dialysis

2017 ◽  
Vol 37 (4) ◽  
pp. 458-463 ◽  
Author(s):  
Rafaela Siviero Caron-Lienert ◽  
Carlos Eduardo Poli-de-Figueiredo ◽  
Ana Elizabeth Prado Lima Figueiredo ◽  
Bartira Ercília Pinheiro da Costa ◽  
Carlo Crepaldi ◽  
...  
Keyword(s):  
Body Composition ◽  
Peritoneal Dialysis ◽  
Nutritional Status ◽  
Membrane Transport ◽  
Dry Weight ◽  
First Year ◽  
Peritoneal Membrane ◽  
Tissue Mass ◽  
Glucose Exposure ◽  
Composition Changes

BackgroundThe characteristics of peritoneal membrane transport differ among patients, affecting the prescription of peritoneal dialysis (PD) modality and glucose exposure in order to achieve an effective dialysis. This study aims to verify the influence of glucose exposure load and peritoneal membrane transport on body composition and nutritional status changes after the first year of PD.MethodsWe examined a cohort of 85 incident PD patients during the first year of treatment. We established a cut-off of 5% to define changes in dry weight (DW), lean tissue mass (LTM), and fat mass (FM).ResultsIn total, 50.6% of the patients presented DW gain, 41.2% showed LTM loss, and 65.9% presented FM gain. Over the time (T0 – T12), we found significant differences in DW, body mass index (BMI), adipose tissue mass (ATM), FM and fat tissue index (FTI). Patients with lower dialysate-to-plasma creatinine ratio showed DW and FM gain. We observed a higher percentage of nonfast transporters in DW gain when comparing with DW no gain. As for glucose exposure load, no body composition changes were seen.ConclusionsMost patients presented DW gain, FM gain, and LTM loss. The characteristics of peritoneal membrane transport affected DW during the first year, changes being greater in nonfast than in fast transporters.

scholarly journals Interactions of Silicon With Essential and Beneficial Elements in Plants

2021 ◽  
Vol 12 ◽  
Author(s):  
Jelena Pavlovic ◽  
Ljiljana Kostic ◽  
Predrag Bosnic ◽  
Ernest A. Kirkby ◽  
Miroslav Nikolic
Keyword(s):  
Transcriptional Regulation ◽  
Nutritional Status ◽  
Nutrient Availability ◽  
Environmental Conditions ◽  
Essential Element ◽  
Nutrient Status ◽  
Tissue Homeostasis ◽  
High Importance ◽  
Beneficial Effects ◽  
Beneficial Elements

Silicon (Si) is not classified as an essential element for plants, but numerous studies have demonstrated its beneficial effects in a variety of species and environmental conditions, including low nutrient availability. Application of Si shows the potential to increase nutrient availability in the rhizosphere and root uptake through complex mechanisms, which still remain unclear. Silicon-mediated transcriptional regulation of element transporters for both root acquisition and tissue homeostasis has recently been suggested as an important strategy, varying in detail depending on plant species and nutritional status. Here, we summarize evidence of Si-mediated acquisition, uptake and translocation of nutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), iron (Fe), zinc (Zn), manganese (Mn), copper (Cu), boron (B), chlorine (Cl), and nickel (Ni) under both deficiency and excess conditions. In addition, we discuss interactions of Si-with beneficial elements: aluminum (Al), sodium (Na), and selenium (Se). This review also highlights further research needed to improve understanding of Si-mediated acquisition and utilization of nutrients and vice versa nutrient status-mediated Si acquisition and transport, both processes which are of high importance for agronomic practice (e.g., reduced use of fertilizers and pesticides).

scholarly journals The effect of silicon (Si) on the growth and nutritional status of Schizolobium amazonicum seedlings subjected to zinc toxicity

2020 ◽  
pp. 325-332
Author(s):  
Gerson Diego Pamplona Albuquerque ◽  
Bruno Lemos Batista ◽  
André Leandro Maia de Souza ◽  
Ana Ecidia de Araújo Brito ◽  
Vitor Resende Nascimento ◽  
...  
Keyword(s):  
Nutritional Status ◽  
Nutrient Solution ◽  
Native Species ◽  
Essential Element ◽  
Zinc Toxicity ◽  
Tolerance Index ◽  
Plant Tolerance ◽  
Randomized Design ◽  
Zinc Levels ◽  
Translocation Factors

Zinc is an essential element to plants. However, excessive zinc levels can severely damage them. Schizolobium amazonicum is an Amazon native species that presents desirable features to remediate environments contaminated with heavy metals. Silicon has the beneficial effect of reducing the toxicity of different contaminants. The aim of the current study is to investigate the effect of Si on the growth and nutritional status of S. amazonicum seedlings subjected to zinc toxicity. The study followed a completely randomized design at 4 x 2 factorial arrangement based on four zinc (1, 150, 300 and 600 μM) and two silicon (0 and 1.5 mM) concentrations with five repetitions for 30 days. Increasing Zn concentrations in the nutrient solution reduced the growth of the plant and Ca, P, Mg, Fe, Mn and Cu contents in plant tissues, increased S concentrations and led to higher toxicity in the roots than shoot of S. amazonicum plants. Si addition to the nutrient solution increased plant growth and the absorption of the evaluated macro and micronutrients. Si increased plant tolerance level from 42.8 to 41.3% at 600 µM Zn, which suggested that this element mitigated the phytotoxic effects of the excess of zinc. Based on the tolerance index, the species presented medium and high tolerance to the evaluated zinc doses. Bioconcentration and translocation factors have indicated the low Zn-phytoextraction capacity of S. amazonicum and suggested that the species may be promising for Zn phytostabilization purposes.

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