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Category: genetics

MIT engineers develop electrochemical sensors for cheap, disposable diagnostics

Using an inexpensive electrode coated with DNA, MIT researchers have designed disposable diagnostics that could be adapted to detect a variety of diseases, including cancer or infectious diseases such as influenza and HIV.

These electrochemical sensors make use of a DNA-chopping enzyme found in the CRISPR gene-editing system. When a target such as a cancerous gene is detected by the enzyme, it begins shearing DNA from the electrode nonspecifically, like a lawnmower cutting grass, altering the electrical signal produced.

One of the main limitations of this type of sensing technology is that the DNA that coats the electrode breaks down quickly, so the sensors can’t be stored for very long and their storage conditions must be tightly controlled, limiting where they can be used. In a new study, MIT researchers stabilized the DNA with a polymer coating, allowing the sensors to be stored for up to two months, even at high temperatures. After storage, the sensors were able to detect a prostate cancer gene that is often used to diagnose the disease.

Over 400 different types of nerve cell have been grown — far more than ever before

Nerve cells are not just nerve cells. Depending on how finely we distinguish, there are several hundred to several thousand different types of nerve cell in the human brain according to the latest calculations. These cell types vary in their function, in the number and length of their cellular appendages, and in their interconnections. They emit different neurotransmitters into our synapses and, depending on the region of the brain – for example, the cerebral cortex or the midbrain – different cell types are active.

When scientists produced nerve cells from stem cells in Petri dishes for their experiments in the past, it was not possible to take their vast diversity into account. Until now, researchers had only developed procedures for growing a few dozen different types of nerve cell in vitro. They achieved this using genetic engineering or by adding signalling molecules to activate particular cellular signalling pathways. However, they never got close to achieving the diversity of hundreds or thousands of different nerve cell types that actually exists.

“Neurons derived from stem cells are frequently used to study diseases. But up to now, researchers have often ignored which precise types of neuron they are working with,” says Barbara Treutlein, Professor at the Department of Biosystems Science and Engineering at ETH Zurich in Basel. However, this is not the best approach to such work. “If we want to develop cell culture models for diseases and disorders such as Alzheimer’s, Parkinson’s and depression, we need to take the specific type of nerve cell involved into consideration.”

For the first time, researchers at ETH Zurich have successfully produced hundreds of different types of nerve cell from human stem cells in Petri dishes. In the future, it will thus be possible to investigate neurological disorders using cell cultures instead of animal testing.

Looking to study neurological conditions, researchers produce over 400 different types of nerve cells

Nerve cells are not just nerve cells. Depending on how finely we distinguish, there are several hundred to several thousand different types of nerve cells in the human brain, according to the latest calculations. These cell types vary in their function, in the number and length of their cellular appendages, and in their interconnections. They emit different neurotransmitters into our synapses, and depending on the region of the brain—for example, the cerebral cortex or the midbrain—different cell types are active.

When scientists produced from in Petri dishes for their experiments in the past, it was not possible to take their vast diversity into account. Until now, researchers had only developed procedures for growing a few dozen different types of nerve cell in vitro. They achieved this using or by adding signaling molecules to activate particular cellular signaling pathways. However, they never got close to achieving the diversity of hundreds or thousands of different nerve cell types that actually exist.

“Neurons derived from stem cells are frequently used to study diseases. But up to now, researchers have often ignored which precise types of neuron they are working with,” says Barbara Treutlein, Professor at the Department of Biosystems Science and Engineering at ETH Zurich in Basel.

Cutting-Edge Gene Therapy Restores Hearing Within Weeks

“This is a huge step forward in the genetic treatment of deafness, one that can be life-changing for children and adults,” says Maoli Duan, consultant and docent at the Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Sweden, and one of the study’s corresponding authors.

Gene therapy involved a synthetic adeno-associated virus (AAV) to deliver a functional version of the OTOF gene to the inner ear via a single injection through a membrane at the base of the cochlea called the round window. The injections were to target mutations in OTOF that can cause deficiencies of the otoferlin protein, that plays key roles in transmitting auditory signals.

According to the researchers, the effects of the gene therapy were rapid, and the majority of the participants recovered some hearing after one month. At a 6-month follow-up, all participants showed considerable improvements, with the average perceptible volume of sound improving from 106 decibels to 52 decibels.

Why some genes are more error-prone: Scientists uncover hidden rule in DNA transcription

Every living cell must interpret its genetic code—a sequence of chemical letters that governs countless cellular functions. A new study by researchers from the Center for Theoretical Biological Physics at Rice University has uncovered the mechanism by which the identity of the letters following a given nucleotide in DNA affects the likelihood of mistakes during transcription, the process by which DNA is copied into RNA. The discovery offers new insight into hidden factors that influence transcription accuracy.

The work is published in the journal Proceedings of the National Academy of Sciences.

The study was authored by Tripti Midha, Anatoly Kolomeisky and Oleg Igoshin. It shows why genetic sequences are not equally prone to errors. Instead, the identity of the two nucleotides immediately downstream of a site significantly alters the error rate during transcription. This discovery builds on prior insights by the same authors on enzymatic proofreading mechanisms, factoring in the effects of distinct kinetics for different nucleotide additions.

Child walks again after receiving experimental treatment for rare genetic condition

In what experts are calling a “dream come true,” scientists used a recent biochemical discovery to help an 8-year-old boy with a rare genetic condition regain mobility.

Researchers from NYU Langone demonstrated, in a study published in Nature on Wednesday, how a chemical precursor to a commonly available enzyme, CoQ10, can help brain cells overcome a rare genetic condition that severely hobbles cells’ energy production process. Without treatment, the boy’s condition is known to deteriorate rapidly and could be fatal.

NYU Langone researchers have helped an 8-year-old boy regain mobility using an experimental treatment.

A molecular switch packs DNA on time for cell division

If measured from beginning to end, the DNA in our cells is too long to fit into the cell’s nucleus, explaining why it must be constantly folded and packaged. When it is time for cell division, and the genetic information needs to be passed on to the next generation, DNA must be packed particularly tightly, or else serious consequences for a cell’s viability might ensue.