BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: ticks

Paving The Way For Discovery: Gene Editing In Ticks

What is something that reminds you of summer and your childhood? For me, it is ticks. I know it sounds strange, but the constant reminders from my parents to “check for ticks” after long summer walks are ingrained in my memory. Although the practice of checking for ticks is common, we don’t often stop to question why, or take a moment to expand our knowledge as to just how dangerous a summer walk in long grass could be. Ticks, although tiny, are powerful, disease ridden organisms and have the potential to spread diseases to humans such as Lyme’s disease, Babesiosis, Anaplasmosis, Tularemia, etc. 

tick

Despite their ability to pass on such a vast variety of pathogens, research on ticks is extremely limited, especially in comparison to similar organisms like mosquitoes. The challenge when it comes to gene editing in ticks is that tick embryos are very difficult to inject due to high pressure in the eggs, a hard outer shell on the egg, and a wax layer outside the embryo created by Gene’s organ. In a recent study published in iScience, researchers developed a tick-embryo injection protocol that aimed to target gene disruption with CRISPR-Cas9 (using both embryo injection and Receptor-Mediated Ovary Transduction of Cargo. In this technique, researchers removed Gene’s organ to prevent the wax coating along with treating the eggs with chemicals such as benzalkonium chloride and sodium chloride to remove the outer shell and relieve the inner pressure. Gulia-Nuss, the co-author of the study and a molecular biologist at the University of Nevada, states: “Another major challenge was understanding the timing of tick embryo development. So little is known about tick embryology that we needed to determine the precise time when to introduce CRISPR-Cas9 to ensure the greatest chance of inducing genetic changes.”

Essentially, the CRISPR-Cas9 system consists of two main molecules that introduce a mutation to the DNA. The first is an enzyme known as Cas9. The function of this enzyme is to cut the strands of DNA at a specific location in order for pieces to be added or removed. As we learned in AP Bio, enzymes are key when it comes to DNA and DNA replication, for they play a variety of roles that allow DNA to replicate the way it does. For example, helicase untwists the double helix at the replication fork, topoisomerase relieves the strain of twisted DNA strands by breaking and rejoining them, and primase synthesizes short RNA strands that act as a primer. Without these enzymes and their very specific purposes, DNA would not be able to replicate. In the case of Cas9, it performs the essential job of cutting DNA in order for gene editing to occur. The second piece of the system is a piece of RNA called guide RNA. The guide RNA binds to a specific sequence in the DNA due to its RNA bases that are complementary to those of the DNA sequence. 

Prior to this study, no lab had displayed the possibility for gene editing in ticks, due to the daunting technical difficulties of such a task. This study is proof to embrace the difficulty and the challenges, in life and in science, for often the most difficult of tasks lead to the greatest outcome. In the case of this study, the discovery of ways in which to target the disruption of genes in ticks will pave the way to the uncovering of the molecular biology of tick-pathogen-host interactions, hopefully in the long run creating ways to prevent and control tick-borne diseases, a process that has the potential to save lives.

Tiny Devils Take Down Gentle Giants all due to Climate Change!

File:Alce (Alces alces), Potter marsh, Alaska, Estados Unidos, 2017-08-22, DD 139.jpg

A innocent female moose, about to be attacked by an onset of terrible parasite in Northeast Canada.

Winter Ticks, not containing Lyme Disease or other Human-harming diseases, are rising exponentially in population throughout New England and Canada, all due to increasingly warmer and snow-free springs and later winters everywhere. As a result, an unlikely species in this region is being targeted by these tick epizootics, Moose, because ticks search for hosts in the fall and other warmer temperatures and stop once freezing weather and snow befalls the land. Yet, when these conditions occur much later, it gives these ticks more time to feast on peaceful animals, and also giving more time for female ticks to fall off its host and create tons more larvae, not making this issue any better. As these raisin sized parasites latch onto to these large creatures, draining so much blood at a time that they simply are unable to function anymore and weakly fall, succumbing to the environment, other predators, or even more ticks. But it’s not simply a few ticks, no, these moose can carry up to around 90,000 ticks! Because of this, there has been “an unprecedented 70 percent death rate of calves over a three-year period” according to a similar source from the University of New Hampshire. Plus, this problem has gotten so bad that now a threatened species in this region of British Columbia, the boreal Caribou, are being eaten alive as well!” If blood loss from heavy tick loads does not directly kill animals, it can make them susceptible to other health risks, Schwantje adds in the original source. “They have spent so much time scratching and chewing on themselves that they haven’t been feeding, so they are in poor body condition,” she says, even with tremendous hair loss that they become basically unrecognizable.

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An example of one of these detrimental winter ticks, a female engorged in size with blood and larvae, ready to reproduce .

But How Can This Be Stopped?

Currently, researchers are offering a multitude of solutions to help save these wonderful species from these terrifying parasites, as Swantje says that “They have huge cultural and nutritional value to our First Nations, And when moose forage in wetlands, they help release nutrients into the environment and make them available to other plants and organisms, studies have shown”, one solution can even be seen here. One possibility is to continuously treat half of the moose with anti-parasite gel and pills that make attached ticks drop from their bodies in order to isolate specifically what the ticks do and don’t do to harm these moose. The other possibility is a highly unlikely one, hunt the moose. Researcher Peter Pekins suggests that “issuing more moose-hunting permits in strategically selected areas” could essentially starve out the ticks in certain areas, yet it is argued that this would only benefit the environment short term, as the climate will continue to warm leading to the growth of more and more ticks.

Who know, if this isn’t stopped soon, ticks will continue to grow in population and maybe even take down us humans! Save the moose (and the caribou)!

Mystery Virus Identified

The Kansas Department of Health and Environment stated that the mysterious virus that killed the farmer in Kansas last summer has been identified as Bourbon virus, named after the county were the patient lived. Doctor Dana Hawkinson, infectious disease specialist, treated the patient for 10 days at the University of Kansas Hospital.  Bourbon virus, a microbe, was identified by the scientist at the federal Centers for Disease Control and Prevention after several months of testing.  Doctor J Erin Staples, a medical epidemiologist at the CDC laboratory in For Collins, CO, stated the virus was a type of thogovirus, part of the larger family called orthomyxovirures.  Hawkinson believe that the virus has been around in milder forms for some time now and people have recovered from it.  The patient entered the hospital with symptoms which included high fever, muscle aches, and loss of appetite.  Upon further testing the patients blood showed elevated liver enzymes and low levels of white blood cells and platelets which indicated tick-borne illnesses.  Hawkinson tested the patient for Rocky Mountain spotted fever and Heartland virus, both came back negative.  Heartland virus is also another recently discovered/named by the CDC tick-borne illness.  There is no treatment for the disease  and the best defense is to wear long garments when working outdoors and wearing bug spray containing DEET.  The risk to the public is low especially because mosquitos and ticks are not active in cold weather.

For more information:

Article from NYTimes

Bourbon virus kills farmer

Virus that killed farmer is identified 

Kansas farmer dead

No More Ticks?

Going to an outdoors summer camp, I had a lot of experience with ticks, these pesky, mosquito like bugs, bites you and stick to your skin. I wish the camp had a way to control their tick infestation, so this article was very intriguing. Ticks, or those pesky bugs that attach to your skin when hiking or walking outdoors, may soon be controlled by fungus.

An important term to know for this article is biological control, which is an attempt to reduce pest population by using “natural enemies” or living organisms (like fungus.)

Biosfork, an agricultural and environmental research firm in Norway, is looking into to the tick infestation problem. Ticks seem like such small harmless bugs, but the tick is a lethal predator for many animals. In sheep, a tick bite can lead to the disease TBF, or Tick Borne Fever. This disease causes high fever and severally compromises their immune systems. As a result many animals die from something as small as a tick bite.

According to their research Biosfork has found that Metarhizium, a pathogenic fungus, can systematically kill ticks. Metarhizium is present in most soils, but scientist at Biosfork feel that releasing this fungus in large quantities in tick invested area will stop the horrible pesky ticks. Biosfork has released this fungus into controlled environments and has found that Metarhizium is a brutal, yet effective way to eliminate these pesky ticks.

This can have many practical applications. By eliminating ticks this fungus could save many sheep pastures by eliminating this pesky predator. Reducing tick populations can make that hike more enjoyable by limiting the pesky tick bites that make the outdoors a nightmare.

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