Research roundup for March 20, 2017

Tardigrades use group of proteins to survive dehydration

UNC scientists found a group of proteins in tardigrades — a microscopic organism that can survive extended periods of time with no water — that help their amazing survival feats.

Previously, many in the scientific community thought tardigrades, better known as water bears, stayed safe during their death-like state using the sugar trehalose. The scientific community thought this because some bacteria and fungi use the sugar to go through the process of vitrification, where the inside of cells are turned into a matrix that protects cell components.

After it was found tardigrades don’t utilize large amounts of trehalose, a research team led by UNC postdoctoral student Thomas Boothby began researching how exactly the tiny creatures stay alive during their bouts without water.

The researchers began their work by drying out the water bears and saw a group of proteins called intrinsically disordered proteins, or IPDs, were being activated. These IPDs, which constantly change shape, create a matrix much like trehalose does.

Boothby said he hopes this discovery can help in transporting pharmaceuticals made out of unstable proteins, cutting costs for transportation in areas of the world where that would limit distribution of medicine.

Thyroid conditions and infant cognition

Results of a clinical trial conducted in part by researchers at UNC Healthcare, UNC Rex Healthcare and WakeMed Health & Hospitals — along with the Maternal-Fetal Medicine Units Network — suggested that treatment for thyroid dysfunction has no effect on infant brain development.

Thirty years of research prior to this concluded that when a pregnant woman’s thyroid fails to produce sufficient levels of the hormone thyroxine, the infant’s brain might not develop as expected. John Thorp, medicine division director at the UNC department of obstetrics and gynecology, said the trial attempted to determine if treating pregnant women with subclinical hypothyroidism and hypothyroxinemia improved the infant’s IQ.

The study discovered that there was no evidence that treating women with these thyroid conditions during pregnancy aided in infant brain development. The mothers underwent regular testing during the first half of pregnancy and half of them received Levothyroxine, a common thyroid medication. Researchers tested the mothers’ thyroids one year after delivery and again five years after delivery. Infants and children received regular development testing for five years after birth.

Plant protein gives bacteria a place in the relationship

Researchers in UNC’s Department of Biology found a protein that can explain the relationship between soil bacteria and plants. 

The protein, PHR1, works to turn on a plant’s response to find more phosphate in the environment which will help the plant grow. Researcher and biology professor Jeff Dangl said it is thought when soil phosphate levels are low, a trend that is becoming more common in soil, the plant takes away energy from immune function and puts it toward looking for the nutrient.

Dangl, along with lead authors of the paper, postdoctoral researchers Gabriel Castrillo and Paulo Teixeira, graduate student Sur Herrera Paredes and research analyst Theresa Law, showed bacteria living in and around plant roots can use this switch to their advantage in a symbiotic relationship. They even found that bacteria can heighten a plant’s phosphate response.

Using Arabidopsis thaliana plants with mutations in the PHR1 protein and a related protein, PHL1, the researchers showed the switch being turned off created an incorrect phosphate response and the colonization of different microbial communities.

The researchers found that some bacteria can turn on and off this protein switch, decreasing a plant’s immune response towards the bacteria, creating a symbiotic relationship. Dangl said if a probiotic approach was used in farming, crops could use less phosphate, which is often wasted in harmful runoff. 

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