Intracellular pH Regulation inRicinus communisGrown with Ammonium or Nitrate as N Source: The Role of Long Distance Transport

1987 ◽  
Vol 38 (4) ◽  
pp. 580-596 ◽  
Author(s):  
SUSAN ALLEN ◽  
J. A. RAVEN
Keyword(s):  
Intracellular Ph ◽  
Ph Regulation ◽  
Long Distance ◽  
Intracellular Ph Regulation ◽  
Long Distance Transport ◽  
N Source ◽  
Distance Transport

Intracellular pH regulation in rabbit S3 proximal tubule: basolateral Cl-HCO3 exchange and Na-HCO3 cotransport

1990 ◽  
Vol 258 (2) ◽  
pp. F371-F381 ◽  
Author(s):  
N. L. Nakhoul ◽  
L. K. Chen ◽  
W. F. Boron
Keyword(s):  
Proximal Tubule ◽  
Intracellular Ph ◽  
Initial Rate ◽  
Ph Regulation ◽  
Basolateral Membrane ◽  
Intracellular Ph Regulation ◽  
S3 Segment ◽  
Absorbance Spectra ◽  
Rule Out

We studied the role of basolateral HCO3- transport in the regulation of intracellular pH (pHi) in the isolated perfused S3 segment of the rabbit proximal tubule. pHi was calculated from absorbance spectra of the pH-sensitive dye dimethylcarboxyfluorescein. Solutions were normally buffered to pH 7.4 at 37 degrees C with 25 mM HCO3- 5% CO2. pHi fell by approximately 0.17 when luminal [HCO3-] was lowered to 5 mM at fixed PCO2 (i.e., reducing pH to 6.8) but by approximately 0.42 when [HCO3-] in the bath (i.e., basolateral solution) was lowered to 5 mM. The pHi decrease elicited by reducing bath [HCO3-] was substantially reduced by removal of Cl- or Na+, suggesting that components of basolateral HCO3- transport are Cl- and/or Na+ dependent. We tested for the presence of basolateral Cl-HCO3 exchange by removing bath Cl-. This caused pHi to increase by approximately 0.23, with an initial rate of approximately 100 X 10(-4) pH/s. Although the initial rate of this pHi increase was not reduced by removing Na+ bilaterally, it was substantially lowered by the nominal removal of HCO3- from bath and lumen or by the addition of 0.1 mM 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) to the bath. The results thus suggest that a Na-independent Cl-HCO3 exchanger is present at the basolateral membrane. We tested for the presence of basolateral Na-HCO3 cotransport by removing bath Na+. This caused pHi to fall reversibly by approximately 0.26 with initial rates of pHi decline and recovery being approximately 30 and approximately 41 X 10(-4) pH/s, respectively. Although the bilateral removal of Cl- had no effect on these rates, the nominal removal of HCO3- or the presence of DIDS substantially slowed the pHi changes. Thus, in addition to a Cl-HCO3 exchanger, the basolateral membrane of the S3 proximal tubule also appears to possess a Na-HCO3 cotransport mechanism. The data do not rule out the possibility of other basolateral HCO3- transporters.

The Role of Amino Acids in the Long-Distance Transport of La and Y in the Xylem Sap of Tomato

2008 ◽  
Vol 129 (1-3) ◽  
pp. 239-250 ◽  
Author(s):  
Jun-liang Wu ◽  
Zheng-gui Wei ◽  
Hai-yan Zhao ◽  
Hui-xin Li ◽  
Feng Hu
Keyword(s):  
Amino Acids ◽  
Xylem Sap ◽  
Long Distance ◽  
Long Distance Transport ◽  
Distance Transport

scholarly journals Myosin-V, Kinesin-1, and Kinesin-3 Cooperate in Hyphal Growth of the FungusUstilago maydis

2005 ◽  
Vol 16 (11) ◽  
pp. 5191-5201 ◽  
Author(s):  
Isabel Schuchardt ◽  
Daniela Aßmann ◽  
Eckhard Thines ◽  
Christian Schuberth ◽  
Gero Steinberg
Keyword(s):  
Fluorescent Protein ◽  
Hyphal Growth ◽  
Myosin V ◽  
Long Distance ◽  
Long Distance Transport ◽  
Conventional Kinesin ◽  
Green Fluorescent ◽  
Mutant Cells ◽  
Distance Transport

Long-distance transport is crucial for polar-growing cells, such as neurons and fungal hyphae. Kinesins and myosins participate in this process, but their functional interplay is poorly understood. Here, we investigate the role of kinesin motors in hyphal growth of the plant pathogen Ustilago maydis. Although the microtubule plus-ends are directed to the hyphal tip, of all 10 kinesins analyzed, only conventional kinesin (Kinesin-1) and Unc104/Kif1A-like kinesin (Kinesin-3) were up-regulated in hyphae and they are essential for extended hyphal growth. Δkin1 and Δkin3 mutant hyphae grew irregular and remained short, but they were still able to grow polarized. No additional phenotype was detected in Δkin1rkin3 double mutants, but polarity was lost in Δmyo5rkin1 and Δmyo5rkin3 mutant cells, suggesting that kinesins and class V myosin cooperate in hyphal growth. Consistent with such a role in secretion, fusion proteins of green fluorescent protein and Kinesin-1, Myosin-V, and Kinesin-3 accumulate in the apex of hyphae, a region where secretory vesicles cluster to form the fungal Spitzenkörper. Quantitative assays revealed a role of Kin3 in secretion of acid phosphatase, whereas Kin1 was not involved. Our data demonstrate that just two kinesins and at least one myosin support hyphal growth.

scholarly journals Enigmatic clusters of sandstone boulders on plateaus of the Stołowe Mountains (Sudetes, south-west Poland) – their geoheritage and geotouristic value

Geologos ◽  
2021 ◽  
Vol 27 (3) ◽  
pp. 141-155
Author(s):  
Piotr Migoń ◽  
Krzysztof Parzóch
Keyword(s):  
Late Cretaceous ◽  
Sedimentary Rocks ◽  
Long Distance ◽  
Long Distance Transport ◽  
South West ◽  
History Of ◽  
Clastic Sedimentary ◽  
Distance Transport ◽  
Plateau Level

Abstract Among sites of geomorphological interest in the tableland of the Stołowe Mountains, consisting of clastic sedimentary rocks of Late Cretaceous age, are enigmatic occurrences and clusters of sandstone boulders within plateau levels that are underlain by mudstones and marls. These boulders are allochthonous, having been derived from the quartz sandstone beds that support the upper plateau level and stratigraphically are in excess of 50 m above the altitudinal position of the boulders. Topographic conditions preclude long-distance transport from the escarpment slopes; boulders are hypothesised to be the last remnants of completely degraded outliers (mesas) of the upper plateau. Their present-day altitudinal position is explained by passive ‘settling’ following disintegration of caprock and denudation of the underlying weaker rocks. Two localities are here presented in detail, Łężyckie Skałki and Pustelnik, along with adjacent boulder trains in the valleys incised into the plateau. It is argued that both localities have considerable geoheritage value and both play the role of geosites, although on-site facilities are so far limited. However, the complex history of boulders sets a series of challenges for successful geo-interpretation.

scholarly journals Cut and paste – Efficient cotyledon micrografting for Arabidopsis thaliana seedlings

2019 ◽  
Author(s):  
Kai Bartusch ◽  
Jana Trenner ◽  
Marcel Quint
Keyword(s):  
Arabidopsis Thaliana ◽  
Success Rates ◽  
Long Distance ◽  
Long Distance Transport ◽  
Light Intensities ◽  
Whole Plant ◽  
Plant Level ◽  
Distance Transport ◽  
Plant Seedlings

AbstractCotyledon micrografting represents a very useful tool for studying the central role of cotyledons during early plant development, especially their interplay with other plant organs with regard to long distance transport. While hypocotyl grafting methods are established, cotyledon grafting is still inefficient. By optimizing cotyledon micrografting, we aim for higher success rates and increased throughput in the model species Arabidopsis thaliana. We established a cut and paste cotyledon surgery procedure on a flat solid but moist surface which improved handling of small plant seedlings. Applying a specific cutting and joining pattern throughput was increased up to 40 seedlings per hour. The combination of short day conditions and low light intensities for germination and long day plus high light intensities and vertical plate positioning after grafting significantly increased ‘ligation’ efficiency. Together, we achieved up to 46 % grafting success in A. thaliana. Reconnection of vasculature was shown by successful transport of a vasculature-specific dye across the grafting site. On a whole plant level, plants with grafted cotyledons match plants with intact cotyledons in biomass production and rosette development. This cut and paste cotyledon-to-petiole grafting protocol simplifies the handling of plant seedlings in surgery, increases the number of grafted plants per hour and produces higher success rates for A. thaliana seedlings. The developed cotyledon micrografting method is also suitable for other plant species of comparable size.

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