BioQuakes

AP Biology class blog for discussing current research in Biology

Author: nukellyicacid

How Do Fish Get Their Shape?

Researchers in The National University of Singapore discovered how fish create their chevron pattern. 

The chevron shape itself and the shape’s function in locomotion have been used to infer the evolutionary relationships among chordates. However, the development of the chevron has not been fully researched until now. 

The research team mainly focused on the myotome, a group of muscles forming the spinal nerve root in fish. These muscles make up most of the fish body and help them become more efficient with side-to-side swimming motion. The myotome creates the “V”  pattern, or chevron pattern, in fish, which helps them increase their swimming efficiency. 

One factor that determines the shape of fish is the friction and stress of their muscles. When the myotome first develops in fish, it forms a cuboidal shape before it deforms into a V shape. Dr. Sham Tlili and Professor Timothy Saunders, head researchers of the project, used zebrafish embryos to examine the deformation process of the myotome from a cuboidal to V shape. Developing myotomes in embryos are connected to embryonic tissues, such as the notochord, and each connection has a varying level of friction. The researchers discovered that the sides of the myotome experience more friction than its central side. 

Picture of chevron pattern on fish

The team also revealed that cells of growing myotome become longer as muscle fibers are formed. This elongation incites a force, which is what creates the “V” pattern on fish. 

Professor Peter Wainwright, a biological professor in UC Davis, also determined that patterns of fish could be split into two groups: midwater fish and deep water fish. “As you get down into the water column, when you have more substrate and more complexity in the habitat, you definitely find more variation and elongation,” said Susman, one of Wainwright’s students. 

Professor Saunders, when asked about the results of the experiment, states that  “This work reveals how a carefully balanced interplay between cell morphology and mechanical interactions can drive the emergence of complex shapes during development. We are excited to see if the principles we have revealed are also acting in the shaping of other organs.”

 

Can Microbes Create Healthier Food?

A specific human gut microbe is making processed foods healthier. 

Researchers at Washington University School of Medicine in St. Louis wanted to find the chemicals in processed foods that correlate to diabetes and heart disease. In their study, the scientists used a bacteria called Collinsella intestinal (bacteria that contains an enzyme to break down Fructoselysine), which breaks down fructoselysine into small, harmless parts. According to Ashley R. Wolf, a researcher in the lab, “Fructoselysine is common in processed food, including ultra-pasteurized milk, pasta, chocolate and cereals.” This chemical has been linked to the cause of many diseases of aging.

When Wolf and her team tested the effects of feeding fructoselysine to mice that had Collinsella intestinalis, they not only discovered an increase in the amount of microbes in the stomach, but also found that the mice’s gut microbes had a stronger ability to break down fructoselysine.

“The new tools and knowledge gained from this initial study could be used to develop healthier, more nutritious foods as well as design potential strategies to identify and harness certain types of gut bacteria shown to process potentially harmful chemicals into innocuous ones,” says Jeffrey I. Gordon, a researcher of the lab.

Picture of human gut microbes

(“Courtesy of Pacific Northwest National Laboratory”)

Another study by Harvard University and the University of San Francisco, discovered that raw food was healthier than cooked food. They found that “cooked food allows the host to soak up more calories in the small intestine, leaving less for hungry microbes further down the gut; on the other hand, many raw foods contain potent antimicrobial compounds that appear to directly damage certain microbes.”

Although more research still has to be done to determine the effectiveness of the microbe, these discoveries help lead people into a healthier lifestyle. 

First Nanolaser That Can Function in Tissue With No Harm

Researchers in Northwestern and Columbia Universities, created a nanolaser that can be used in the near future for the imaging of living tissue. 

Being very thin, “1/1000th the thickness of a single human hair”, and made mostly of glass, which is biocompatible, the nanolaser is able to fit in the tissue with ease. 

Besides the specificity of the shape, the nanolaser can “effectively deliver visible laser light at penetration depths accessible to longer wavelengths,” said Northwestern’s Teri Odom, who co-led the research. The nanolaser has to not only be able to emit longer wavelengths in order to penetrate deeper into the tissues, but also be able to emit shorter wavelengths that are needed in the tissue.

Other scientists have created small-sized nanolasers before, but they all needed ultraviolet light to power them. “This is bad because the unconventional environments in which people want to use small lasers are highly susceptible to damage from UV light and the excess heat generated by inefficient operation,” says P. James Schuck, an associate professor of mechanical engineering at Columbia.

The researchers at Columbia and Northwestern were able to solve the issue using photon upconversion. This process creates a pattern of absorbing two or more photons that leads to a shorter wavelength and higher energy than the original. The researchers were able to generate visible photons from infrared photons. 

Pictured above is photon upconversion

With all these benefits, the nanolaser can be used potentially to create different types of laser therapy in order to help alleviate neurological disorders, such as Alzheimer’s and Parkinson’s. Furthermore, it can also help diagnose diseases. As discovered in University of Arkansas, the laser can be used to heat up tumor cells to be detected through ultrasound. 

 

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