The Hanging Gardens of the World

Smog is something that impacts many cities around the world, especially those that are heavily built-up. Major cities in central and northern China, like Beijing, welcomed in the New Year with orange and red alerts for smog. Red alerts are the highest on the air pollution scale, usually resulting in schools and factories to close. And China’s air pollution is not a new problem, but is steadily getting worse.

Solutions? Build vertical gardens. This is not a new concept, but it is brilliantly shown by Singapore’s exquisite Gardens by the Bay. The 18 Supertrees, concrete towers encased in a steel frame, are covered with over 162,900 tropical plants originating from all over the world. These plants were chosen based on 7 different criteria, including tolerance to vertical planting, lack of soil, hardiness, and easy maintenance. Not only are these plant-clad structures highly visually-stimulating, but they also connect to some of the cooled conservatories resulting in air being recycled between conservatory and Supertree.

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Singapore’s Supertrees in the Gardens by the Bay (O.Cousins)

With Singapore aiming to cut its carbon emissions by 10% by 2020, it is hoped that the construction of these monolithic trees will raise more public awareness of the environment and how our actions can affect it.

Hanging gardens have been trialed all around the world, but covering an entire skyscraper or residential building block in lush green plants is not that easy. But that hasn’t stopped Stefano Boeri and his big leafy dreams. An architect from Milan, he owns Boeri Studio, and is already part of several projects that are taking the importance of biodiversity, climate change, urban design, and European culture into architectural design. The threat of climate change is no longer a threat, it is happening. Vertical ForestING is a concept Stefano started in 2014 when Boeri Studio designed, constructed and completed the first vertical forest in Milan.

Trees have been planted on each level, as many as can fit in one hectare of forest. The idea was to improve residential living, but ensure that urban planning did not come at a cost to the environment. By building up, it helps to eliminate urban sprawl. By adding hundreds of plants from flowering plants to small trees, not only is it creating something artistically beautiful, but it also adds biological diversity in a heavily populated urban area. The trees and shrubs provide shade, attract small wildlife, and help contribute to cleaner air.

Now, Stefano has set his sights on building more vertical cities, this time in Nanjing, China. The project aims to replicate Bosco Verticale, with 2 residential towers covered from head to toe in trees, shrubbery and hanging plants. But it also becomes part of a bigger project: Forest City. The concept of the vertical forests has been up-scaled, with a whole city designed with multiple skyscrapers covered in hanging gardens and surrounded by parks. Shijiazhuang will be the site of a new kind of city, housing 100,000 people comprising of 225 hectares. Instead of a city sprawling outwards, this city will sprawl upwards, leaving more land for natural preservation and agriculture. Due to the sheer number of trees and shrubs on one building, one square metre is anticipated to absorb 0.4 kg of CO2 a year. The green facade also helps to maintain cooler temperatures within the buildings.

The concept of vertical gardens is certainly not new, but over the last few years it has developed further. The idea of architecture being sustainable and using renewable energy sources is exciting. Constructing more vertical forests could certainly play a part in combating heavy smog and pollution in cities, and hopefully help to mitigate climate change.

I mean who wouldn’t want to wake up to green every day?

#cityjungle

 

 

Top feature image credit: Stefano Boeri Architetti

Genetic modification with a twist!

DNA editing has always been a controversial topic, with many countries around the globe, particularly in Europe, refusing to grow or import crops that have been genetically modified. General concerns range from risk of cross contamination of GM crops with non-GM plant species, to risks to human consumption of GM foods.

Many experiments have been run to test different outcomes and effects of genetically modified crops, to identify advantages and any disadvantages or risks to cultivating GM on a commercial scale. Several countries already grow a considerable amount of GM crops, though most of these crops are for animal feed or for use as biofuel, with the US, Argentina and Brazil as the biggest growers of GM.

Because of the concerns about GM, scientists are now trying to find other ways to manipulate plants in order to improve crop production. And we might have a possible solution.

A team in South Korea, led by Je Wook Woo at the IBS Center for Genome Engineering in South Korea, have recently published a paper, outlining their most recent experiment, where they managed to edit and manipulate plants without inserting foreign DNA into the genetic code. As it stands, conventional genetic modification results from inserting DNA from another species of plant or other organism into the chosen plant for modification.

Here’s some background information. Genome editing has actually been used for quite a number of years, used to enhance many beneficial qualities in crop plants. It creates very precise targeted mutations within the cell and uses artificial enzymes – molecules which create breaks in the DNA sequence. Under natural circumstances, if a break occurs in the DNA sequence within a cell, the cell will automatically try to repair it using one of two repair mechanisms, either non-homologous end joining or homologous recombination.

DSBs

A single stranded break, or double stranded breaks can create mutations in DNA.

Non-homologous end joining basically involves joining the broken DNA strands together, and is really susceptible to errors, often mutating and inactivating a gene as a result. However, if the cell has a suitable DNA template available for repairing the broken DNA strands, it will recreate the DNA sequence that was lost or broken via homologous recombination. This process of homologous recombination is actually more accurate, so you get an exact copy of the original DNA sequence, and everything is as good as new.

Scientists can artificially make breaks in the DNA sequence of a plant using an artificial enzyme. Instead of allowing the cell to provide its own repair template, scientists can provide a synthetic repair template. The synthetic repair template could be a new DNA sequence which codes for a new gene, for example giving the plant resistance to a particular disease. One genome editing technique used is the CRISPER-Cas9 system.

This system was first identified in bacteria, as part of their immune system response if under pathogen attack, and scientists thought it would be a good idea to use it for targeting genes for genetic modification. The CRISPR-Cas9 system uses a molecule, called a single guide RNA, to find and latch onto a gene which is the target for genetic modification. An enzyme, called Cas9, comes along and breaks up the targeted gene. The cell then repairs the broken DNA sequence using a synthetic repair template. And voilà you have a new gene incorporated into your plant’s DNA.

What Je Wook Woo and his team did was create pre-assembled ribonucleoproteins, which are effectively protein-RNA complexes. They mixed the Cas9 enzyme with single guide RNA molecules which targeted genes from 3 plant species. Once they had this mixture of molecules, they infected plant cells from tobacco, lettuce and rice with it to create mutations in the target genes.

Nature article Je Wook Woo

Lettuce seedlings with the edited DNA sequence (taken from Je Wook Woo’s paper, see link below).

The results were that the Cas9-ribonucleoprotein complex created mutations in the target genes of the plant cells immediately after infection. The Cas9-ribonucleoprotein complex was quickly degraded by the cell once it had created the mutations so it couldn’t mutate anything else in the cell. The bonus factor of this experiment, was that these gene mutations remained in the DNA even after the plant cells had regenerated themselves. The team was able to grow seeds from the plants with the edited DNA, and the offspring still maintained the genetic mutation.

nbt.3389-SF5

Different stages of tobacco plant cell regeneration, showing wild type (WT) and mutant (bi-allelic KO) plants (taken from Je Wook Woo’s paper, see link below).

No need for inserting foreign DNA as a repair template!

The IBS team have made a revolutionary discovery; they have now paved a path to engineer plants that might not be subjected to GMO regulations, since foreign DNA was not actually inserted. Hopefully, in the next few years, we can see some more progress in this area.

Saving agriculture one cell at a time!

Link to journal paper:

Woo, J. W., Kim, J., Kwon, S. I., Corvalan, C., Cho, S. W., Kim, H., Kim, S.-G., Kim, S.-T., Choe, S. & Kim, J.-S. (2015) DNA-free genome editing in plants with preassembled CRISPR-Cas9 ribonucleoproteins. Nature Biotechnologyhttp://www.nature.com/nbt/journal/vaop/ncurrent/full/nbt.3389.html

“The science that will transform our future.”

This blog post was written last month for a science communication competition, in which we had to write an article about the science that we thought would transform our future.

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The art of science has changed dramatically over the last 100 years, and it continues to change and evolve as time passes, and as we gather more information about the world. From Isaac Newton’s discovery of gravity, to Gregor Mendel’s realisation of the rules of genetics using humble garden peas, to Charles Darwin’s proposal of the theory of evolution, science encompasses so many different topics, and each of them are all applicable to our lives in one form or another. But have you ever wonder how many scientific discoveries can be attributed to plants? Plants have helped shape the world, and are necessary for survival. The things that are possible with plants are boundless, and here are just a few of their potentials.

As more land is being used up for infrastructure, housing, mining and agriculture, the race is on to find suitable land for raising even more livestock and growing crops to cope with rising population numbers. When all the suitable fertile land is expended, we will have to turn to less fertile land or brownfield sites contaminated with hazardous wastes, such as deserts or abandoned mines, respectively. If it were possible to produce crops on these soils, it would both jeopardise their health and yield. The use of genetically modified (GM) crops, aquaponics, and phytoremediation are three possible solutions to this problem.

Although heavily controversial, GM has the ability to transform global agriculture, by increasing crop yield and tolerance to saline soils, drought conditions, toxic metals or pesticides. A really good example of how genetic modification was successful can be seen with the case of drought-tolerant barley. Scientists from the John Innes Centre, alongside the University of Jordan developed a barley variety that is four times as drought tolerant than its parent stock. Dr Wendy Harwood, at the John Innes, explained that due to poor water availability in many countries, GM can definitely make a positive impact, especially when we consider that approximately 70% of global water is used for agriculture. They were able to identify a gene that regulates opening and closing of stomata, the small pores on leaf surfaces. The gene was subsequently altered so that during times of water scarcity, the stomata would close, thus avoiding water loss through these pores, and therefore being more drought resilient.

Plants also have natural abilities to adapt to environmental changes and develop new tolerance strategies. Phytoremediation, the use of plants to clean up both soils and water of toxic waste metals, has shown to be a promising technology, not to mention environmentally friendly. The most commonly used method is phyotextraction, where plants accumulate heavy metals from soils, which are then extracted and safely treated. These hyperaccumulator plants absorb metals, chemically bind them to organic compounds, and sequester these modified compounds in storage vessels within their cells, thus avoiding metal poisoning and damage. A high biomass and ability to accumulate metals quickly and efficiently are the two most desirable traits in a hyperaccumulator. This can be further enhanced by using genetic modification to generate plants more tolerant to toxic waste substances, and modify their uptake and regulation in the plant.

Deserts or areas of soil infertility could still be used to grow crops without the excessive need for fertilisers with the help of aquaponics. It combines the raising of aquatic animals, such as freshwater fish (aquaponics), with growing plants in water (hydroponics). The plants get their necessary nutrients from the aquaculture effluent which is fed into the hydroponic system. Any organic matter in the water is broken down by nitrification bacteria, which convert ammonia into nitrates for plants to absorb. Once the water has been stripped of its nutrients, it is oxygenated and recycled back into the aquaculture tank. This system has been successful with several vegetable varieties, including lettuce, tomatoes and peppers benefiting from this symbiotic environment.

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Aquaponics growing system

None of these three technologies are perfect, and they lend themselves to further study; but the possibilities are endless. This is an opportunity to use science to counteract climate change and improve lives through increasing food provisions to avoid malnutrition and starvation.

But in the meantime, it’s back to the lab.

Purple tomatoes – fruit of the scientists

The tomato, a relative of the potato, is one of the most popular fruits. Their famous red colour is due to anthocyanins, a group of water-soluble pigments, belonging to the class of flavonoids. Fruits containing these compounds often appear as red, blue or purple. Anthocyanins have antioxidant properties, often deactivating and removing free radicals – highly reactive molecules due to unpaired electrons, that have the potential to cause cellular damage. Therefore, anthocyanins are seen to help minimise damage to cells and their signalling pathways, and reduce inflammation. Because of their ‘superfood’ status, they have been the focus of many scientific studies.

Genetic modification has been used on some crops to enhance and increase levels of antioxidants in fruits, as a way of bringing new health benefits to the consumer. A really good example of how GM was successful can be seen with the case of the purple tomatoes. They were developed by Prof Cathie Martin and her colleagues at the John Innes Centre. Their main focus was to breed tomatoes with a higher level of anthocyanins, using a GM technique. Two genes were identified from two different plant species, and inserted into the DNA of the tomato plant. One gene was taken from Arabidopsis thaliana (a common weed used as a model for many plant experiments), and the gene was shown to be responsible for the activation of flavonoid biosynthesis. The other gene identified came from a common garden flower, the snapdragon, and it is responsible for the production of anthocyanins in the colourful flowers.

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Arabidopsis thaliana

snapdragon

Snapdragon flower

 

 

 

 

 

 

 

 

 

The lab was successful in producing three sets of tomatoes. Insertion of the Arabidopsis or snapdragon gene produced tomatoes that were purple or orange, respectively. These tomatoes were compared to the wild type red tomatoes. Also, further experimentation of using all three genes simultaneously resulted in tomatoes with dark indigo fruit.

ripening purple tomatoes

Ripening of red, purple and indigo tomatoes

The result was that the purple and indigo tomatoes did indeed have a substantially higher proportion of anthocyanins than the naturally red tomatoes. This also meant a significant increase in levels of antioxidants. They then tested the health benefits of these tomatoes further, by supplementing them into the diets of cancer-prone mice. As a result, their lifespans were significantly extended. Of course, mice are not quite the same as humans, so it would be necessary to conduct clinical studies with human participants. However, because of Europe’s overall negative attitude towards GM, Prof Martin took her research to Canada, with the aim of developing food products containing purple tomato juice. Across the seas, clinical trials with purple tomato juice are now in the pipeline.

You might be wondering why the need for GM when naturally purple-skinned tomatoes do exist. But in actual fact, these purple tomatoes don’t have the same levels of anthocyanins compared to the GM purple tomatoes. GM purple tomatoes have anthocyanins present throughout the skin and flesh unlike their traditionally bred counterparts. Not only that, higher levels of anthocyanins have been proven to double the shelf life of tomatoes. Studies show that anthocyanins help delay over-ripening of the fruits, therefore reducing the risk of infection by fruit molds. Surely a benefit to the food industry?

All in all, I think an important point should be made from all of this. If we are to help global populations fight against hunger, malnourishment and disease, we need to stop looking at how a food product is made and instead focus on the health benefits that it can provide.

Maybe it’s time to give purple tomatoes a go.

Algae biofuels – a blooming business

Algae. Some are green, some are red, some are brown. Some are slimy, tiny or huge. On first glance, you would think that they don’t do much, that they just sit there passively waiting out life’s storms and seasons. But on a microscopic level they come to life. Each algal cell has the fundamental organelles which help with the cell’s day to day running, such as a nucleus, mitochondria, ribosomes (the control centre, powerhouse and protein construction workers of the cell) . But they also contain chloroplasts. These little photosynthetic factories house chlorophyll molecules which ultimately absorb energy from light and turn it into sugars.

Simple cartoon of an algae cell

Simple cartoon of an algae cell

Scientists have taken advantage of these little sugar-making factories, and in turn tried to create a renewable alternative to fossil fuel. The result? Algae biofuels. Today, the two main production systems used are open pond systems and closed photobioreactors. Open ponds are basically huge ponds (artificial or natural) filled with algae. Contamination is a risk, so algae strains that are able to dominate wild strains of algae are preferable. With closed photobioreactors, the algae ‘soup’ is contained in a network of small clear tubes, which are exposed to light. These can be very expensive to build and maintain.

Open pond raceway

Open pond raceway

Closed system - photobioreactor

Closed system – photobioreactor

Rapid algae growth is further encouraged by the addition of sugars, CO2 and nutrients such as Nitrogen, Phosphorus and Potassium. Under these conditions, algae production can be all year round. Once the algae has grown to the desired quantity, it is collected and separated from its water solution. Once the algae has dried, the lipid content is extracted to make biodiesels. The carbohydrate biomass of algae can also be fermented to produce bioethanol. The great thing about algae biofuel production is that it reduces competition for arable land and fresh water resources, since algae can grow in brackish water, saline or wastewater.

Studies have been conducted around the world, and theoretical findings suggest that algae biofuels have the potential to produce between 10 and 100 times more fuel per unit area than other biofuels. If this can be confirmed on a commercial scale, we may have found a possible solution to our diminishing fossil fuel crisis.  The high-oil productivity of algae biofuels makes it an even more desirable alternative fuel. Algae with high-oil production are reported to generate more than 50,000 Litres of oil per hectare, per year. To produce this amount of oil, the amount of arable land (in the U.S.A.) necessary for algae biofuels would amount to less than 2.5%. And the resulting biofuel would cover 50% of US transport fuels! Now that’s what I call a pretty nifty turnover.

This is only a snippet of all the amazing things that can be achieved using algae. Development of algae biofuels is not an immediate solution to fossil fuels, but it is a start. By alleviating some of the environmental pressures associated with fossil fuels, and utilising natural resources in a healthier way through biofuel production, maybe we can meet rising world energy demands, and still create a better, cleaner future.

In the meantime, maybe I’ll set up my own backyard algae biofuel lab.