Related Experiment Video
Updated: Jul 12, 2026
08:15
Membrane Remodeling of Giant Vesicles in Response to Localized Calcium Ion Gradients
Published on: July 16, 2018
Cytosolic pH Gradients Associated with Tip Growth
Science (New York, N.Y.)
|March 11, 1994
Summary
A cytosolic pH gradient is crucial for polar tip growth in Pelvetia embryos. This pH gradient, linked to calcium, directly influences tip elongation rates and is essential for cell growth.
Area of Science:
- Cell Biology
- Plant Physiology
- Developmental Biology
Background:
- Polar tip growth is a fundamental process in plant development.
- The role of intracellular pH gradients in directing cell growth remains an area of active research.
Purpose of the Study:
- To investigate the presence and function of a cytosolic pH gradient in Pelvetia embryo rhizoid cells.
- To determine the relationship between the pH gradient, calcium distribution, and polar tip growth.
Main Methods:
- Utilized pH-sensitive microelectrodes for precise cytosolic pH measurements.
- Employed ratio imaging techniques to visualize pH and calcium gradients.
- Applied chemical treatments (propionic acid, lanthanum) to perturb gradients and assess growth responses.
Main Results:
- Growing rhizoid cells exhibited a longitudinal pH gradient, with the apex being more acidic (0.3-0.5 pH units).
- Disruption of the pH gradient with propionic acid inhibited tip elongation.
- The magnitude of the pH gradient strongly correlated with the rate of tip elongation.
- The pH gradient spatially overlapped with a cytosolic calcium gradient; inhibiting calcium fluxes abolished the pH gradient and growth.
Conclusions:
- A cytosolic pH gradient is essential for polar tip growth in Pelvetia rhizoids.
- Calcium fluxes play a critical role in establishing and maintaining this pH gradient.
- The interplay between pH and calcium gradients is vital for directional cell elongation.
More Related Videos
Related Concept Videos
01:29Electron Transport Chain Components
The electron transport chain (ETC) is a crucial metabolic pathway that facilitates energy conversion in prokaryotic and eukaryotic cells. In eukaryotes, the ETC comprises four membrane-associated protein complexes in the inner mitochondrial membrane. In prokaryotes, the ETC in the plasma membrane can vary in composition, with fewer or different complexes depending on the organism and environmental conditions. These complexes transfer electrons from electron donors, such as NADH and FADH2, to...
01:27ATP Driven Pumps I: An Overview
ATP-driven pumps, also known as transport ATPases, are integral membrane proteins. They have binding sites for ATP located on the membrane's cytosolic side and the ion-conducting domain in the transmembrane region. These pumps use the free energy released from ATP hydrolysis to move the solutes across cell membranes against an electrochemical gradient.
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and are...
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and are...
01:26Transport Across the Golgi
While it is unclear how molecules move between adjacent Golgi cisternae, it is apparent that the molecules move from cis- cisterna, the entry face, to the trans- cisterna, the exit face. Experiments initially suggested vesicles that bud from one cisterna and fuse with the next cisterna to transport proteins between the cisternae. This vesicular transport model describes the Golgi apparatus as a relatively static structure with a unique enzyme composition in each cisterna. Molecules are...
01:22Protein Transport to the Thylakoids
Thylakoids are membrane-bound sac-like structures within the chloroplast that serve as sites for photosynthesis. Thylakoid lumen contains many electron transport proteins and is enclosed by a thylakoid membrane rich in the light-harvesting complex. Proteins targeted to the thylakoids are transported as precursors and are sorted by the general TOC/TIC import pathway. Once the precursor reaches the stroma, stromal processing peptidases remove their transit signal and expose thylakoid signal...
01:59The Phragmoplast
Cell division is essential for organismal growth and development. In animal cells, the central spindle and its associated proteins form the midbody, a structure that has an essential role in cytokinesis. In plants, the central spindle, along with the microtubules, actin, and other cell components, matures into the phragmoplast, which is necessary for cytokinesis. Unlike the stationary midbody, the phragmoplast expands centrifugally, eventually leading to the formation of the new cell wall.
The...
The...
01:21Electrochemical Gradient and Channel Proteins: An Overview
An electrochemical gradient is a fundamental concept in biology and chemistry. It regulates the movement of ions across cell membranes. This movement is influenced by two factors:
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to the...