AP Biology class blog for discussing current research in Biology

Tag: potassium

How Is The Discovery Of Potassium and Sodium Ions in Cell Organelles Important to Health and Disease?

Laboratory scientists Junyi Zou and Palapuravan at the University of Chicago shed light on the crucial role of potassium and sodium ions within the specific compartments inside a cell. The role of ions within a cell was a section of biology many scientists couldn’t conquer and left many scientists questioning if cells regulate ions?

Junyi Zou and Palapuravan collaborated with their professor, Yamuna Krishnan, to develop a miniature device made of DNA that enabled them to peer into the intricate workings of live cells. Thanks to the biological compatibility of DNA with cells, this innovative device seamlessly infiltrated the cell and provided the scientists with a unique window into the cell’s interior. However, Junyi Zou and Palapuravan needed to reach specific compartments of the cell: the lysosome and recycling endosomes. (Recycling endosomes are responsible for facilitating the transit of ion channels to and from the cell membrane). To accomplish this task, Junyi Zou and Palapuravan, who studied the presence of various ions in different organelles, utilized sensors to target the organelles they were researching. Once the sensors reached their designated cellular locations, they lit up whenever they came into contact with an ion. This enabled Junyi Zou and Palapuravan to quantitatively evaluate the presence of ions by measuring the brightness of the sensors.

After completing his research, Palapuravan, who focused on tracking potassium ions within the recycling endosomes, determined there are ion channels in organelles. Ion channels, which are a form of facilitated diffusion withIon-Channel Receptor channel proteins, are protein molecules that span across the cell membrane and allow ions to pass through their channels from high to low concentration without the need for ATP. Ion channels are also involved in Parkinson’s disease; however, current medications for Parkinson’s disease only target ion channels on the plasma membrane and not within the cell. If Parkinson’s medication can be developed to target ion channels within cells as well, does this imply a potential cure for Parkinson’s disease? I don’t know, but it is exciting to learn that ongoing research is aimed at curing the incurable! It gives us hope for future research and discoveries.

Finally, after completing his research, Junyi Zou, who focused on tracking sodium ions in lysosomes, determined that lysosomes regulate cellular sodium. Lysosomes, which are made in the rough ER, are hydrolytic sacs of enzymes that enable animal cells to digest macromolecules. Following Junyi Zou’s completed research, we can now say that lysosomes assist cells in regulating their sodium levels. These lysosomes are known as lysosomal sodium-transporting proteins. Now, we can include additional information in our cell notes packet on lysosomes! Feel free to leave a comment on my post and, if you do, list one fact that you found really interesting!

Bacteria may be more complex than we think

Photo by Wikimedia Commons

A common public misconception is that bacteria live alone and act as solitary organisms. This misconception, however, is far from reality.

Bacteria always live in very dense communities. Most bacteria prefer to live in a biofilm, a name for a group of organisms that stick together on a surface in an aqueous environment. The cells that stick together form an extracellular matrix which provides structural and biochemical support to the surrounding cells. In these biofilms, bacteria increase efficiency by dividing labor. The exterior cells in the biofilm defend the group from threats while the interior cells produce food for the rest.

While it has long been known that bacteria can communicate through the group with chemical signals, also known as quorum sensing, new studies show that bacteria can also communicate with one another electrically. Ned Wingreen, a biophysicist at Princeton describes the significance of the discovery; “I think these are arguably the most important developments in microbiology in the last couple years, We’re learning about an entirely new mode of communication.”

An entirely new mode of communication it is! Heres how it works:

Ion channels in a bacteria cell’s outer membrane allow electrically charged molecules to pass in and out, just like a neuron or nerve cell. Neurons pump out Sodium ions and let in Potassium ions until the threshold is reached and depolarization occurs. This is known as an action potential. Gurol Suel, a biophysicist at UCSD emphasizes that while the bacteria’s electrical impulse is similar to a neuron’s, it is much slower, a few millimeters per hour compared to a neuron’s 100 meters per second.

Photo by Chris 73 Wikimedia Commons

So what does this research mean?

Scientists agree that this revelation could open new doors to discovery. Suel says that electrical signaling has been shown to be stronger than traditional chemical signaling. In his research, Suel found that potassium signals could travel at constant strength for 1000 times the width of a bacteria cell, much longer and stronger than any chemical signal. Electrical signaling could also mean more communication between different bacteria. Traditional chemical signaling relies on receptors to receive messages, while bacteria, plant cells, and animal neurons all use potassium to send and receive signals. If these findings are correct, there’s potential in the future for the development of new antibiotics.

Learning about electrical signaling in bacteria has complicated our understanding of these previously thought to be simple organisms. El Naggar, another biophysicist at USC says, “Now we’re thinking of [bacteria] as masters of manipulating electrons and ions in their environment. It’s a very, very far cry from the way we thought of them as very simplistic organisms.”



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