Navigation Links
When green algae run out of air

When green algae "can't breathe", they get rid of excess energy through the production of hydrogen. Biologists at the Ruhr-Universitt Bochum have found out how the cells notice the absence of oxygen. For this, they need the messenger molecule nitric oxide and the protein haemoglobin, which is commonly known from red blood cells of humans. With colleagues at the UC Los Angeles, the Bochum team reported in the journal "PNAS".

Haemoglobin an old protein in a new look

In the human body, haemoglobin transports oxygen from the lungs to the organs and brings carbon dioxide, which is produced there, back to the lungs. "However, scientists have known for years that there is not just the one haemoglobin", says Prof. Thomas Happe from the Work Group Photobiotechnology. Nature has produced a large number of related proteins which fulfil different functions. The green alga Chlamydomonas reinhardtii has what is known as a "truncated" haemoglobin, the function of which was previously unknown. Happe's team has deciphered its role in surviving in an oxygen-free environment.

In an oxygen-free environment, the green alga activates specific genes

When Chlamydomonas has no oxygen available, the algae transfer excess electrons to protons, creating hydrogen (H2). "For this to work, the green alga activates a certain gene programme and creates many new proteins", Happe explains. "But how exactly the cells even notice that oxygen is missing is something we did not know." The research team looked for genes that are particularly active when green algae have to live without oxygen and found a gene that forms the blueprint for a haemoglobin. In an oxygen-rich environment, however, this gene was completely idle.

A haemoglobin and nitric oxide help green algae to survive

The scientists studied the haemoglobin protein and its genetic blueprint in more detail using molecular biological and biochemical analyses. "One thing became clear very quickly", says Dr. Anja Hemschemeier from the Work Group Photobiotechnology. "Algae in which we switched this gene off could hardly grow without oxygen." From previous studies it is known that in many organisms, haemoglobin detoxifies nitric oxide, because an overdose of this gas poisons the cells. The biologists therefore tested whether green algae which are no longer able to form haemoglobin after genetic manipulation die of nitric oxide poisoning. Their expectations: the green algae should fare better if the gas is removed using a chemical scavenger. "Surprisingly, then the algae were not able to grow at all", says Hemschemeier. The researchers concluded that, under oxygen-free conditions, haemoglobin and nitric oxide are in cahoots.

Nitric oxide signals: "no oxygen!"

Nitric oxide acts in many living organisms as a signalling molecule apparently also in green algae. Experiments in vitro have shown that the green algal haemoglobin interacts with nitric oxide. When the researchers artificially introduced the gas to the single cell organisms, certain genes became active that are otherwise only "turned on" in the absence of oxygen. "From all this data we can conclude that Chlamydomonas uses nitric oxide to pass on the 'no oxygen!' signal within the cell, and that our haemoglobin is involved in this process", Happe sums up. His team wants to go on exploring the role of this protein in green algae, as the biologists have discovered another eleven haemoglobin genes in the organism. "Now things are really getting going", says the Bochum scientist. "The map of haemoglobin research has many blank spots that we want to fill with content. The fact that a single cell requires twelve haemoglobin proteins indicates that these fulfil finely tuned functions in the cell."


Contact: Dr. Thomas Happe
Ruhr-University Bochum

Related biology news :

1. Too green to be true? Researchers develop highly effective method for converting CO2 into methanol
2. Lab experiments question effectiveness of green coffee bean weight-loss supplements
3. Wood not so green a biofuel
4. Research on geological storage of CO2 to reduce greenhouse gas emissions
5. Living biofilters could reduce greenhouse gas emissions
6. Elevated carbon dioxide making arid regions greener
7. Recovery of Hawaiian green sea turtles still short of historic levels, Stanford-led study suggests
8. Going green: Nation equipped to grow serious amounts of pond scum for fuel
9. Cameroon researcher wins prestigious Green Oscar
10. Zeal to ensure clean leafy greens takes bite out of riverside habitat in California
11. More food and greener farming with specialised transporters for plants
Post Your Comments:
(Date:10/23/2015)... GOLETA, California , October 23, 2015 /PRNewswire/ ... SensoMotoric Instruments (SMI) announce a mobile plug and play ... during interactive real-world tasks SensoMotoric Instruments (SMI) ... their established wearable solutions for eye tracking and physiological ... captured with SMI Eye Tracking Glasses 2w ...
(Date:10/22/2015)... Oct. 22, 2015  Synaptics (NASDAQ: SYNA ), a leading ... first quarter ended September 30, 2015. --> ... fiscal 2016 grew 66 percent over the comparable quarter last year ... 2016 was $23.8 million, or $0.62 per diluted share. ... the first quarter of fiscal 2016 grew 39 percent over the ...
(Date:10/22/2015)... 2015 NXT-ID, Inc. (NASDAQ: ... company focused on the growing mobile commerce market and ... year collaboration with well-known celebrity Joey Fatone . ... ,      (Photo: ) ... 1995 to 2002, Joey was part of one of ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... The Global Genomics Industry ... and in-depth study on the current state of ... ) , The report provides ... classifications, applications and industry chain structure. The Genomics ... including development trends, competitive landscape analysis, and key ...
(Date:11/24/2015)... Therapeutics, Inc. (NASDAQ: HALO ) will be presenting at the ... on Wednesday, December 2 at 9:30 a.m. ET/6:30 a.m. PT . ... a corporate overview. th Annual Oppenheimer Healthcare Conference ... a.m. PT . Jim Mazzola , vice president of ... --> th Annual Oppenheimer Healthcare Conference in ...
(Date:11/24/2015)...  Clintrax Global, Inc., a worldwide provider of clinical research services ... that the company has set a new quarterly earnings record in ... growth posted for Q3 of 2014 to Q3 of 2015.   ... , with the establishment of an Asia-Pacific ... United Kingdom and Mexico , ...
(Date:11/24/2015)... York , November 24, 2015 ... a recent market research report released by Transparency Market ... to expand at a CAGR of 17.5% during the ... Prenatal Testing Market - Global Industry Analysis, Size, Volume, ... the global non-invasive prenatal testing market to reach a ...
Breaking Biology Technology: