Difference between revisions of "Team:SZU-China/Description"

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<h1>Design</h1>
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<h1>Description</h1>
 
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<div id="Background" class="indent">
 
<div id="Background" class="indent">
 
<h2>Background</h2>
 
<h2>Background</h2>
 
<p>
 
<p>
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As the background, we described, to solve the problem that cockroaches’ flooding in the home environment, we use the transformation of the chafer and the green deadlock to achieve the effect of killing the cockroaches. In order to ensure the killing ability of <i>Metarhizium anisopliae</i> to the cockroaches, we improved in three ways: the adhesion, penetration, and survivability.
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Cockroaches are among the most common and obnoxious household pests, they harbor in damp and unsanitary
−
 
+
places such as sewers, garbage disposals, kitchens, and bathroom, feed on human’s and pet’s food. Besides
 +
its importance as a sign of poor sanitation, cockroaches have been implicated in the transmission of several
 +
pathogenic organisms such as <i>E.coli</i> and <i>Salmonella enteritidis</i> which can cause diarrhea, pneumonia and so
 +
on.<sup>[1]</sup>, also, expose to cockroach feces and body parts of dead roaches over time can trigger
 +
allergies and asthma<sup>[2]</sup>. So it’s not safe to ignore these pests.
 +
 
</p>
 
</p>
 
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<div id="Current" class="indent">
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<h2>Which chassis to choose and why?</h2>
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<h2>Current solution</h2>
 
<p>
 
<p>
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The chassis organism we chose was <i>Metarhizium anisopliae</i>. This is an entomogenous fungus that infects more than 200 species of insects, most of which are agricultural pests also includes cockroaches. Its infection process is divided into the following steps: spore attachment -- penetration of the body wall -- in vivo colonization -- killing the host -- re-spore formation. It is a natural insecticide tool, and by transforming it, we can make better use of it.
+
People rack their brains about cockroach control. Currently, there are two mainstream ways
 +
to control the population of cockroaches, physical and chemical methods. However, a
 +
chemical method like foggers, boric acid, and gel bait may cause environmental toxicity
 +
and the development of resistance in cockroaches<sup>[3]</sup>. A physical method such as
 +
“cockroach house”, only trap few cockroaches. Neither chemical nor physical method can’t
 +
achieve the goal of environment-friendly and efficient control.
  
 
</p>
 
</p>
  
 
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<div id="solution" class="indent">
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<h2>How to achieve?</h2>
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<h2>Our solution</h2>
 
<p>
 
<p>
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We designed the system to transform <i>Metarhizium anisopliae</i> from three parts:
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This year’s SZU China team want to tackle the cockroach control issue by using synthetic biology.
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<b>HsbA</b>, <b>Bbchit</b> and <b>MCL1</b>.
+
We choose a kind of entomogenous fungi, <i>Metarhizium anisopliae </i>, as biological chassis.
 +
It is considered a safe and prospective choice for causing disease in insects only. But its lethality
 +
is still needed to be improved, which limits it's widespread used. We construct a system to enhance
 +
its virulence. Our system contains three parts: HsbA, BbChit, and MCL1. These three genes work
 +
sequentially during infecting cockroach, promote adhesion, penetration, and immune-avoidance respectively.
 +
  
 
</p>
 
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<b>HsbA</b>: The HsbA from Beauveria bassiana encodes a kind of membrane surface hydrophobic protein which helps our spores adhere to the wax on the cockroach body surface. Moreover, with the overexpression of HsbA, our spores can more effectively adhere to the cockroach. Then it will follow as spores’ germination, germinal tube, appressorium, and the next penetrating process.
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<h3 style=" color: #469789;">HsbA</h3>
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<b>Bbchit</b>: Cockroaches’ body wall composed of protein, chitin, and lipids. Bbchit is a chitinase gene which comes from Beauveria bassiana. It can " bore a hole" by decomposing chitin on the cockroaches. Thereby allowing the hyphae to enter the cockroaches’ body.
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<p>
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</p>
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It encodes hydrophobic surface binding protein A, located on the surface of fungus.  
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This protein works like “glue” by forming a hydrophobic bond between spores and the waxy
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epicuticle of their host.
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<p>
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</p>
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<b>MCL1</b>: Cockroaches’ immune system is powerful. If there is no effective response, our chassis will be recognized and killed by blood cells. The MCL1 gene from Metarhizium Robertsii can encode a protein similar to host collagen, which binds to the surface of our chassis and masks β-1,3-glucan (an antigen that can be recognized by blood cells), thus enabling <i>Metarhizium anisopliae</i> escapes the immune response of cockroaches.
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<h3 style=" color: #469789;">Bbchit</h3>
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<video width="100%" height="100%" controls>
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<p>
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<source src="https://static.igem.org/mediawiki/2018/e/e4/T--SZU-China--description_min.mp4" type="video/mp4">
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It encodes chitinase, which can hydrolyze chitin. Chitosan is the major part of the insect
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</video>
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body wall, chitinase can hydrolyze this to penetrate.
 +
</p>
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</div>
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<div class="card-body text-center">
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<h3 style=" color: #469789;">MCL1</h3>
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<p>
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It encodes a collagen-like protein, which can combine with β-glucan.β-glucan is distributed on the cell wall surface of fungus and is the recognization site for insect hemocytes to combine and clear invader. MCL1 acts like putting an “invisible cloak” on the fungus. so that fungus can evade being recognized by the host immune system.
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<div id="safety" class="indent">
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<div class="indent">
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How to ensure safety?
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<p>
 
<p>
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Then, we design a trap box named GreenGround to bring our idea into real world. We mix spores,banana powder and oil together to form emulsifiable powder,which is applied to non-woven fabrics for use.
−
We built a safety mechanism for our system. It consists of a tryptophan attenuator and a MazF venom protein both come from the prokaryotic system. To make it expressed in our chassis organisms, we added a Kozak sequence to the front of these two parts. We put a suitable concentration of Tryptophan while we are culturing the fungi, and the cockroach inside contains Tryptophan. In both of the environment, the Tryptophan attenuator makes a difference that stops the translation before MazF, and then the fungi can keep alive. If the fungi abscise the environment we mention above, the Tryptophan attenuator would not work and the MazF expresses to make them die quickly.  
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<div id="Suicide" class="indent">
 +
<h2>Suicide switch</h2>
 +
<p>
 +
We built a safety mechanism for our system. It consists of a tryptophan attenuator and a MazF venom protein. In the cultivating and cockroaches environment, the Tryptophan attenuator makes a difference that stops the translation before MazF, and then the fungi can keep alive. If the fungi abscise the environment we mention above, the Tryptophan attenuator would not work and the MazF expresses to make them die quickly.<sup>[4]</sup>
  
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<h2>Reference</h2>
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<p>
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[1] Mpuchane S, Matsheka IM, Gashe BA, Allotey J, Murindamombe G, Mrema N. Microbiological studies of cockroaches from three localities in Gaborone, Botswana. Afr J Food Nutr Sci. 2006;6:56–59.
 +
</p>
 +
<p>
 +
[2] Gore JC, Schal C,Cockroach allergen biology and mitigation in the indoor environment. Annu Rev Entomol. 2007; 52():439-63.
  
 +
</p>
 +
<p>
 +
[3] Wu X, Appel AG.J Econ Entomol. 2017 Jun 1;110(3):1203-1209.
 +
</p>
 +
<p>
 +
[4] Sowa S M, Keeley L L. Free amino acids in the hemolymph of the cockroach, Blaberus discoidalis[J]. Comparative Biochemistry & Physiology Part A Physiology, 1996, 113(2):131.
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Revision as of 18:36, 16 October 2018

Description

Background

Cockroaches are among the most common and obnoxious household pests, they harbor in damp and unsanitary places such as sewers, garbage disposals, kitchens, and bathroom, feed on human’s and pet’s food. Besides its importance as a sign of poor sanitation, cockroaches have been implicated in the transmission of several pathogenic organisms such as E.coli and Salmonella enteritidis which can cause diarrhea, pneumonia and so on.[1], also, expose to cockroach feces and body parts of dead roaches over time can trigger allergies and asthma[2]. So it’s not safe to ignore these pests.

Current solution

People rack their brains about cockroach control. Currently, there are two mainstream ways to control the population of cockroaches, physical and chemical methods. However, a chemical method like foggers, boric acid, and gel bait may cause environmental toxicity and the development of resistance in cockroaches[3]. A physical method such as “cockroach house”, only trap few cockroaches. Neither chemical nor physical method can’t achieve the goal of environment-friendly and efficient control.

Our solution

This year’s SZU China team want to tackle the cockroach control issue by using synthetic biology. We choose a kind of entomogenous fungi, Metarhizium anisopliae , as biological chassis. It is considered a safe and prospective choice for causing disease in insects only. But its lethality is still needed to be improved, which limits it's widespread used. We construct a system to enhance its virulence. Our system contains three parts: HsbA, BbChit, and MCL1. These three genes work sequentially during infecting cockroach, promote adhesion, penetration, and immune-avoidance respectively.

HsbA

It encodes hydrophobic surface binding protein A, located on the surface of fungus. This protein works like “glue” by forming a hydrophobic bond between spores and the waxy epicuticle of their host.

Bbchit

It encodes chitinase, which can hydrolyze chitin. Chitosan is the major part of the insect body wall, chitinase can hydrolyze this to penetrate.

MCL1

It encodes a collagen-like protein, which can combine with β-glucan.β-glucan is distributed on the cell wall surface of fungus and is the recognization site for insect hemocytes to combine and clear invader. MCL1 acts like putting an “invisible cloak” on the fungus. so that fungus can evade being recognized by the host immune system.

Then, we design a trap box named GreenGround to bring our idea into real world. We mix spores,banana powder and oil together to form emulsifiable powder,which is applied to non-woven fabrics for use.

Suicide switch

We built a safety mechanism for our system. It consists of a tryptophan attenuator and a MazF venom protein. In the cultivating and cockroaches environment, the Tryptophan attenuator makes a difference that stops the translation before MazF, and then the fungi can keep alive. If the fungi abscise the environment we mention above, the Tryptophan attenuator would not work and the MazF expresses to make them die quickly.[4]

Reference

[1] Mpuchane S, Matsheka IM, Gashe BA, Allotey J, Murindamombe G, Mrema N. Microbiological studies of cockroaches from three localities in Gaborone, Botswana. Afr J Food Nutr Sci. 2006;6:56–59.

[2] Gore JC, Schal C,Cockroach allergen biology and mitigation in the indoor environment. Annu Rev Entomol. 2007; 52():439-63.

[3] Wu X, Appel AG.J Econ Entomol. 2017 Jun 1;110(3):1203-1209.

[4] Sowa S M, Keeley L L. Free amino acids in the hemolymph of the cockroach, Blaberus discoidalis[J]. Comparative Biochemistry & Physiology Part A Physiology, 1996, 113(2):131.