Team:Osaka/Project

From 2010.igem.org

(Difference between revisions)
Line 6: Line 6:
<h3>Background</h3>  
<h3>Background</h3>  
-
<p>
 
-
Desert covers one-fifth of the world's land area, and is inhabited by one-sixth of the world's population, i.e. over a billion people. More serious, however, is desertification - a decrease in soil productivity resulting in loss of fertile land. 40% of the Earth's land area is arid and vulnerable to desertification, and its consequences to the inhabitants - including starvation and poverty - form a major problem.</p>
 
-
 
-
<p>
 
-
Desertification results from a combination of natural and human-related factors.
 
-
</p>
 
-
<p>
 
Arid regions tend to experience large fluctuations in precipitation. In those regions, rainfall tends to be infrequent and brief but in heavy volume, leading to erosion of and leeching of nutrients from the soil. Also, drought sometimes occur for long periods, hindering the growth of vegetation. According to some reports, precipitation is correlated to plant cover; consequently a vicious cycle of reduced precipitation and loss of vegetation is induced, finally leading to desertification.
Arid regions tend to experience large fluctuations in precipitation. In those regions, rainfall tends to be infrequent and brief but in heavy volume, leading to erosion of and leeching of nutrients from the soil. Also, drought sometimes occur for long periods, hindering the growth of vegetation. According to some reports, precipitation is correlated to plant cover; consequently a vicious cycle of reduced precipitation and loss of vegetation is induced, finally leading to desertification.
</p>
</p>
over-grazing and over-cultivation are among the human causes of desertification
over-grazing and over-cultivation are among the human causes of desertification
 +
population increase in arid regions of developing countries fuels need for higher food production - expansion of agriculture and livestock grazing area
-
乾燥地帯の開発途上国では人口が増加しています。そのため食料増産が必要となり、未開拓の土地へと進出しなければなりません。これらの土地の生産能力は低く過剰な負荷によりすぐに荒廃してしまします。一度荒廃した土地を回復させることは困難でさらなる土地へ進出しなければならず沙漠化を招いてしまいます。
+
already low productivity - stressed beyond capacity - rapid loss of fertility
-
　沙漠化の防止としては植林や灌漑施設の設置が行われていますがそのすべてが成功しているわけではありません。沙漠化した土地は荒廃しており水分も少なくなっています。その様な土地に無計画に植林することは土地の劣化を速めてしまいます。また、灌漑は設備の設置や維持に費用が掛かり、設備の運転には多くのエネルギーが必要です。十分量の水を供給できなければ土壌中の塩類が地表面に集積してしまい植物が育たなくなってしまいます。
+
instead of restoring this exhausted land, which is difficult, further expansion to new areas
-
　そこで私たちは沙漠化した土地の植生を回復させる持続的緑化サイクル(Continuous Greening Cycle)を考えました。これを菌体によって構築することにより生態系を回復させ土地の緑化を目指しました。
+
-
　このサイクルは次の要素から成り立っています。
+
-
一つ目は保水性ポリマー、ポリγグルタミン酸の生産です。このポリマーを菌体に作らせることで本来蒸発によって失われる水分を土壌中に保持します。植物の成長を助け乾季での枯死を減少させます。
+
reforestation, irrigation system - not successful
-
二つ目は木質を分解する酵素を菌体が作ることです。ポリマーによって土壌中の保持水分を増やしても残念ながら枯死してしまう植物もあります。これらを分解して菌体の栄養素とすることで菌体を増やしてポリマーを増産させます。
+
沙漠化した土地は荒廃しており水分も少なくなっています。
-
　植林時に以上の機能を持った菌体とポリマーを混ぜた土壌を付加することで持続的にサイクルが回り始め緑地が拡大していきます。最終的には広大な沙漠は緑に覆われ生態系が回復します。このContinuous Greening Cycleを説明したアニメーションを用意したのでご覧ください。
+
 
-
<a href="https://2010.igem.org/Team:Osaka/Project_animation">Watch the animation of our project. </a>
+
その様な土地に無計画に植林することは土地の劣化を速めてしまいます。
 +
 
 +
また、灌漑は設備の設置や維持に費用が掛かり、設備の運転には多くのエネルギーが必要です。
 +
 
 +
十分量の水を供給できなければ土壌中の塩類が地表面に集積してしまい植物が育たなくなってしまいます。
 +
 
 +
In searching for a way to apply bioengineering to the problem of desertification,
 +
 
 +
low cost, low energy, sustainable desert greening that can be easily implemented in developed and developing countries alike
-
low cost, low energy, sustainable desert greening
 
-
can be easily implemented in developing countries
 
-
開発途上国でも容易に導入可能で飢餓や貧困に苦しむ人々を沙漠化の脅威から救うことができます。
 
</p>
</p>
Line 45: Line 42:
<h3>The Cycle</h3>
<h3>The Cycle</h3>
<p>We envisioned a <b>Continuous Greening Cycle</b> in which engineered microorganisms decompose plant fibers into nutrients through the action of cellulolytic enzymes. They then produce water-holding polymers such as poly(gamma-glutamic) acid that retain water in the soil to help plants grow. When the plants die they will be decomposed to start the cycle anew.</p>
<p>We envisioned a <b>Continuous Greening Cycle</b> in which engineered microorganisms decompose plant fibers into nutrients through the action of cellulolytic enzymes. They then produce water-holding polymers such as poly(gamma-glutamic) acid that retain water in the soil to help plants grow. When the plants die they will be decomposed to start the cycle anew.</p>
 +
<p><a href="https://2010.igem.org/Team:Osaka/Project_animation">Watch the animation of our project. </a>
 +
</p>
<h3>Cellulose degradation</h3>
<h3>Cellulose degradation</h3>

Revision as of 13:42, 27 October 2010

Project: The Continuous Greening Cycle

Background

Arid regions tend to experience large fluctuations in precipitation. In those regions, rainfall tends to be infrequent and brief but in heavy volume, leading to erosion of and leeching of nutrients from the soil. Also, drought sometimes occur for long periods, hindering the growth of vegetation. According to some reports, precipitation is correlated to plant cover; consequently a vicious cycle of reduced precipitation and loss of vegetation is induced, finally leading to desertification.

over-grazing and over-cultivation are among the human causes of desertification population increase in arid regions of developing countries fuels need for higher food production - expansion of agriculture and livestock grazing area already low productivity - stressed beyond capacity - rapid loss of fertility instead of restoring this exhausted land, which is difficult, further expansion to new areas reforestation, irrigation system - not successful 沙漠化した土地は荒廃しており水分も少なくなっています。 その様な土地に無計画に植林することは土地の劣化を速めてしまいます。 また、灌漑は設備の設置や維持に費用が掛かり、設備の運転には多くのエネルギーが必要です。 十分量の水を供給できなければ土壌中の塩類が地表面に集積してしまい植物が育たなくなってしまいます。 In searching for a way to apply bioengineering to the problem of desertification, low cost, low energy, sustainable desert greening that can be easily implemented in developed and developing countries alike

Objectives

We had 3 objectives in mind when planning this project:

  1. To address environmental issue of desertification
  2. To investigate the feasibility of engineering a cyclic biological system
  3. To contribute to iGEM and Synthetic Biology by developing and characterizing new parts

The Cycle

We envisioned a Continuous Greening Cycle in which engineered microorganisms decompose plant fibers into nutrients through the action of cellulolytic enzymes. They then produce water-holding polymers such as poly(gamma-glutamic) acid that retain water in the soil to help plants grow. When the plants die they will be decomposed to start the cycle anew.

Watch the animation of our project.

Cellulose degradation

Cellulase

Polyglutamic acid (PGA) synthesis

Gamma polyglutamic acid

Parts

Construction of the parts for cellulose degradation and PGA synthesis outlined above formed the majority of our wet lab work. We produced a collection of new BioBricks by PCR from existing plasmids or genome DNA, and also made some constructs to test the new parts. For more info, please see Parts.

Tests

We ran several tests to confirm the working of our parts, as well as characterize them quantitatively. See the Tests page for more info.

Modeling

We also attempted to construct a model and simulate it using software in order to determine the feasibility of the cycle as well as identify important parameters involved. See the Modeling page for more info.

Summary of results

Plans for future work

References

  • 門村浩、武内和彦、大森博雄、田村俊和『環境変動と地球砂漠化』、朝倉書店（1991）
  • 吉川賢、山中典和、大手信人『乾燥地の自然と緑化－砂漠化地域の生態系修復に向けて』、共立出版（2004）
  • 日本沙漠学会編『沙漠の事典』、丸善株式会社（2009）
  • MIILENNIUM ECOSYSTEM ASSESSMENT，http://www.maweb.org/en/index.aspx
    • © iGEM OSAKA 2010 All rights reserved

    Retrieved from "http://2010.igem.org/Team:Osaka/Project"