BioQuakes

AP Biology class blog for discussing current research in Biology

Author: theroid

New anti-CRISPR Proteins Serving as Impediments to this Miraculous System.

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On March 17, 2019

In Student Post

CRISPR-Cas9 systems are bacterial immune systems that specifically target genomic sequences that in turn can enable the bacterium to fight off infecting phages. CRISPR stands for “clusters of regularly interspaced short palindromic repeats” and was  first demonstrated experimentally by Rodolphe Barrangou and a team of researchers at Danisco. Cas9 is a protein enzyme that is capable of cutting strands of DNA, associated with the specialized stretches of CRISPR DNA.

Diagram of the CRISPR prokaryotic antiviral defense mechanism.

Recently, a blockage to the systems was found by researchers which are essentially anti-CRISPR proteins. Before, research on these proteins had only showed that they can be used to reduce errors in certain genome editing. But now, according to Ruben Vazquez Uribe, Postdoc at the Novo Nordisk Foundation Center for Biosustainability (DTU), “We used a different approach that focused on anti-CRISPR functional activity rather than DNA sequence similarity. This approach enabled us to find anti-CRISPRs in bacteria that can’t necessarily be cultured or infected with phages. And the results are really exciting.” These genes were able to be discovered by DNA from four human faecal samples, two soil samples, one cow faecal sample and one pig faecal sample into a bacterial sample. In doing so, cells with anti-CRISPR genes would become resistant to an antibiotic while those without it would simply die. Further studies found 11 DNA fragments that stood against Cas9 and through this, researchers were ultimately able to identify 4 new anti-CRIPRS that “are present in bacteria found in multiple environments, for instance in bacteria living in insects’ gut, seawater and food,”  with each having different traits and properties.  “Today, most researchers using CRISPR-Cas9 have difficulties controlling the system and off-target activity. Therefore, anti-CRISPR systems are very important, because you want to be able to turn your system on and off to test the activity. Therefore, these new proteins could become very useful,” says Morten Sommer, Scientific Director and Professor at the Novo Nordisk Foundation Center for Biosustainability (DTU). Only time will tell what new, cool, and exciting discoveries will be made concerning this groundbreaking system! What else have you guys heard? Comment below!

A Baby Beetle’s Nursery is.. In a Dead Mouse?!

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On January 15, 2019

In Student Post

Two Parent Burying Beetles in a Dead Rodent! Gross!

Typically, death for animals is experienced at the end of one’s life, but this is reversed for a certain species of carrion beetle, Nicrophorus vespilloides or burying beetle, in which infant beetles are born and raised within dead mice carcasses. In this mice carcass, parent beetles frequently tend to the dead animal by soaking it with their own oral and anal secretions, providing the baby beetle with a much needed dark microbial film. This bacterial goo actually closely resembles the parent beetle’s gut microbiomes, allowing for the baby beetle to truly thrive as an offspring of this beetle.

But why give these baby beetles this goo within a dead carcass? What benefit would that ever give to an insect?

In every living thing, there is sphere of personal bacteria that provide much needed life benefits as well as qualities like your own stench. Plus, bacteria can even join together through various forms of cellular communication, making an almost impenetrable microfilm biome for bacteria to live in, as seen in plaque on human teeth. This same function is what helps support infant beetles with necessary nutrients and life benefits by keeping the cadaver fresh and capable of sustaining youngster life. Plus, it even causes dead bodies to smell actually not terrible, but instead more pleasant! Crazy! “What burying beetle parents can do with a small dead animal is remarkable,” says coauthor Shantanu Shukla of the Max Planck Institute for Chemical Ecology in Jena, Germany.  “It looks different. It smells different. It’s completely transformed by the beetles.”

If these insects aren’t exposed to these microbiomes as a child, there could be some serious detrimental effects. As shown by Shukla’s lab work, larvae grown in cadavers that were swept clean of biofilm by Shukla and her colleagues used their food less efficiently and gained less weight (“roughly third less weight per gram than those who had their parents goo”).

But, the parents are not the only ones who manipulate the carcass, which can be seen here. As parent beetles and tended to their goo in the body and guarding their children, the infant beetles also add their own secretions to the dead mouse and also eat away the bacteria as well as the entire mouse body. “What will remain is the tail of the mouse,” Shukla says, “and the skull and a few pieces of skin.”

Isn’t it simply crazy how much bacteria can contribute to the growth of a baby insect as well as its impact on even a dead animal? Comment below about what YOU think about this!

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

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On January 14, 2019

In Student Post

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.

File:Ixodus ricinus 5x.jpg

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)!

The Zombie Apocalypse is Coming! – Sort of…

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On October 10, 2018

In Student Post

Imagine a disease that, once it infects another organism, it completely takes control of their body and uses it for further infection and mutilation. This is exactly what is happening in the incredibly noisy (100 decibels to be exact) seasonal insects, named the periodical cicada (Magicicada sp.). However much you might like or absolutely hate these insects (like me), they unfortunately are suffering from a rampant parasitic fungus that is essentially taking control of these bugs and turning them into zombies. This zombie fungus is incredibly brutal to the cicadas, causing their almost-lifeless body to be driven around by this fungus, losing parts of their own body while gaining another cicadas head that becomes attached during forced copulation by the fungus to infect more cicadas. It is pretty much like “The Walking Dead” in the insect world, with cicadas being driven around by a parasite infecting others at a rapid speed with insect parts flying all over the place. 

This fungus, the Massospora cicadina, typically begins its infection on the insect when the cicada nymphs come to the surface after about 17 years of feeding off of plant roots underground. When the come up, about 3-5 percent of the cicadas are infected by spores, which are conidia or asexually reproducing cells, and multiply by the thousands within the bug while hoping to spread to more and more cicadas in the trees. This is known as the stage I infection. A stage II infection by this parasite consists of sexually produced spores whose goal is to end up in the soil and wait, withstanding all environments, until the next cicada arises. After the infection takes place of either type of spore, the cicada essentially falls apart as their abdomen enlarges with white-spores, losing their reproductive segments as well as several of their limbs. But the catch is that, of course, the cicada doesn’t realize and therefore it carries on with its barely lifeless self and performs the tasks of any normal cicada. Including more copulation.

Pictured here is a Cicada affected with this fungus, missing half of its abdomen.

Not only do the cicadas with stage I walk around constantly with their open wound and drag along spores while the cicadas with stage II fly around spreading spores from their abdomen, but this zombie parasite also tremendously manipulates the insects sexual behaviors. As stated in the original paper in Scientific Reports, “It is relatively common to find a healthy cicada with its genitalia plunged into the abdominal spore mass of an infected partner or to see healthy cicadas attached to fragments of abdomen or terminalia that have torn free from infected partners during attempted copulation.”. But that’s not all. These parasites also cause male cicadas to take up female mating behavior and flick their wings in response to other male cicadas. One thing leads to another, and now it has been concluded that this fungus is more present in male cicadas since these infected males are now more willing to mate with both female and male cicadas, spreading the infection to both. Although many scientists and researchers (including myself) thought that maybe this parasite simply caused a feminizing effect within the insects, this practice of male wing flicking only occurs in cicadas with a stage I infection. Therefore this disproves what was previously hypothesized, since if this feminizing effect was a case, it would occur in every infection, not just the first stage.

Either way, these spores have been researched to manipulate and control a cicada’s behavior, whether it be sexual or not. But, who knows what this parasite might mean for humans as we already know how brutal and sadistic it can be. Do you think that this topic should be more heavily researched for not only cicadas wellbeing but also ours?

But next time you see a cicada, be careful it doesn’t look to you to turn you into the next real life zombie!

To read more about this new parasite affecting cicadas in the original source, click here.

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