A team of scientists from Northern Arizona University (USA) have developed a new system able to identify different genetic strains of the tuberculosis (TB)-causing bacterium, Mycobacterium tuberculosis, which has now been patented.
TB is one of the most deadly and common infectious diseases today. The CDC estimates that more than a third of the world’s population is infected with M. tuberculosis. Each year, approximately 9 million people become ill with TB and 2 million of those die.
“The ability of the disease to develop resistance to treatments and to travel easily across borders makes worldwide TB control efforts critical”, according to a March news release from the CDC.
“The technique provides a faster, cheaper and more precise method of testing for these strains”, said Paul Kleim, the lead member of the team and Northern Arizona University Regents Professor and the Cowden Endowed Chair in Microbiology. Also working on the project is James Schupp, Assistant Director of the Microbial Genetics and Genomics Center at Northern Arizona University, and Robert Scott Spurgiesz, a former undergraduate student.
The system has been described by Kleim as ‘molecular sleuthing’ and it is thought that its speed and accuracy will boost efforts to identify the source of TB infection. The DNA of an infected individual will be compared with other samples stored in a national database in order to trace the point of origin of any given infection.
“We can identify where a TB infection came from and control it at its source”, said Kleim.
The system, newly patented, holds promise for the commercial production of kits. “Very few companies will risk their capital on commercialization efforts unless there is patent protection for an invention first”, he said.
Parasite cell structure to lead to new treatments for tropical infectious disease
Cellular biologists at the University of Georgia, USA, have developed new molecular tools to study and localize glycosylphosphatidylinositols (GPIs) for the first time in living organisms in order to understand how they work in tropical parasites that cause human disease. GPIs are cellular lipids that are involved in many important biological functions, not least in disease transmission.
Some GPIs are ‘attached’ to protein cells, while other GPIs are ‘free’. It is these free cellular wanderers that interest Kojo Mensa-Wilmot, Professor of Cellular and Molecular Biology, and Sandesh Subramanya, a former doctoral student at the University of Georgia department of cellular biology. With the aid of these new tools, whole new areas of investigation have been opened up, with the hope of further elucidating the function of GPIs.
GPIs have numerous functions; they are hydrocarbon-containing organic compounds that living cells all possess in order to maintain their structure and be able to function. Glycolipids are attached to carbohydrates, and they are involved with cellular energy and also serve as markers for cellular recognition.
The researchers discovered that these glycolipids are cleaved in response to cell stress as a result of changes in osmotic pressure and relative acidity or alkalinity – a function previously unknown.
The research is particularly important in order to better understand the parasite Trypanosoma brucei, which causes human African trypanosomiasis, a disease that affects more than 66 million people in 36 countries of sub-Saharan Africa.
“We found that putting these cells under stress similar to that initially encountered by the trypanosome inside the fly caused the parasites to cleave free GPIs”, said Mensa-Wilmot “and that gives us important information about how the trypanosome cell functions.”
Furthermore, the tool works just as well in understanding the parasite Leishmania, which leads to the disease leishmaniasis. Leishmaniasis occurs in more than 88 countries where a third of a billion people are at risk of contracting it.
The researchers also found a new pathway for protein movement in the trypanosome that may also be found in other cell types including humans. Furthermore, proteins can move from a glycosome, an important energy-generating organelle in a trypanosome, to the endoplasmic reticulum where GPIs are made, in response to cell stress. The new research will open up whole new areas for further investigation.
“Before this work in trypanosomes, there was no evidence that we could ‘catch’ peroxisome proteins moving to the endoplasmic reticulum”, said Mensa-Wilmot. “With better understanding of the process we could begin looking for compounds that may act as drugs by blocking the parasite’s ability to respond to extracellular stress.”
More mysteries of HIV and SARS are revealed
Scientists from the universities of Oxford and Cambridge, UK, have revealed one of the key biological processes used by viruses, such as HIV and severe acute respiratory syndrome (SARS), when they replicate.
Viruses interfere with host cell processes that our bodies use to replicate cells, and protein synthesis is often one of their targets. For the first time, researchers have been able to witness virus-induced frameshifting in action, and have been able to identify crucial roles of particular elements.
The research, funded by the Biotechnology and Biological Sciences Research Council, The Medical Research Council, The Royal Society and The Wellcome Trust, brings us closer to understanding and therefore combating these viruses.
The research has revealed the workings of the process known as ‘ribosomal frameshifting’ which results in a mis-reading of the genetic code during protein synthesis. In order for genes to be accurately expressed the frame of the genetic code, which has a three-nucleotide periodicity, must be translated correctly. Viruses are able to force the ribosome to back-up by one nucleotide, resulting in the production of a different frame and synthesis of different viral proteins. These are exploited by viruses and help them to survive and multiply.
Ian Brierley, the project leader at the University of Cambridge said: “This collaborative project was set up with Robert Gilbert’s team in Oxford to investigate the structure of a frameshifting ribosome using electron microscopy. The images we obtained give us an insight into how a virus-encoded RNA pseudoknot can induce frameshifting and may be useful in designing new ways to combat virus pathogens that use this process.”
Their findings have been published in the journal Nature, 11 May 2006.
Professor Julia Goodfellow, Chief Executive of the Biotechnology and Biological Sciences Research Council, and one of the main funders said: “This is exciting and valuable research and demonstrates clearly why investment in fundamental science is so important. The treatments and therapies that we now take for granted are based on decades of work by scientists furthering our understanding of natural processes. The work to explore fundamental biology today is laying the foundation for potential medical applications over the next 20 years.”
Lasers targeted on infection detection
Jim Piper, the 2006 Carnegie Centenary Professor and Deputy Vice Chancellor and Professor of Physics at Macquarie University in Sydney, Australia, is to spend the next 6 months visiting key Scottish institutions and delivering his speech on the development and applications of lasers.
Piper believes that lasers, whose invention was an almost accidental development after the Second World War, could have even greater potential applications in the future.
“After the war there was a lot of old radar equipment hanging around and researchers going back to university after their national service played around with it. When lasers were developed they were just a scientific curiosity, indeed in the 1960s they were dubbed a solution without a problem, but applications were developed very quickly.”
“The earliest applications were in medicine, initially ophthalmology and the military, mainly guidance and ranging, two areas which continue to be central. Over the past 40 years, laser use has spread into a huge range of areas, including widespread medical use, CDs and supermarket scanners, in cars and manufacturing, environmental measurement and underwater sensing. And I believe even more exciting applications are just over the horizon.”
Piper and his team in Sydney are currently working on the development of laser-based systems which could provide high-speed testing for medical pathogens. “At present specimens have to be grown in the lab then identified by the 100-year-old technology of a person peering down a microscope. This is time consuming and resource intensive. Doctors, health professionals and patients need a way to check for pathogens such as Cryptosporidium, Staphylococcus, TB or Legionella quickly, and we believe that systems combining lasers and photonics could provide high-speed, on-line detection. There’s even the possibility that in the future we could see systems allowing noninvasive detection of pathogens within the body.”
African leaders vow to work towards universal access to HIV, TB and malaria treatment
At the end of a 3-day African Union (AU)-backed summit on HIV/AIDS, TB and malaria, African leaders have renewed their commitment to work together towards providing universal access for sufferers living with the diseases in Africa.
Nigerian President Olusegun Obasanjo said the summit ended with a “renewed commitment” of the leaders to meet the targets agreed in Abuja in 2000 and 2001 as the United Nations’ (UNs) Millennium Development Goals.
“We have now agreed that we are going to have universal access. Universal access is not talking of 80%, not even 90%. It’s 100% access to preventive and treatment services”, he said
The AU chairman, Congo’s President Dennis Sassou-Nguesso, said the meeting adopted three important documents, one of which was the Abuja Call for Accelerated Action towards Universal Access to HIV/AIDS, TB and malaria.
The Abuja document details six goals to be achieved by 2010, including: providing basic services to at least 5 million children who have lost parents to the diseases, ensuring that at least 80% of people have access to voluntary HIV testing and counseling services, ensuring that 80% of people have access to condoms for HIV prevention and ensuring that all HIV-positive people living with TB have access to antiretroviral drugs and counseling.
In addition, the declaration calls for the promotion of partnerships, research and development, and strengthening oversight, evaluation and reporting mechanisms, as well as greater civil society and private sector involvement in controlling the three diseases. African leaders have also adopted a common position for the UN General Assembly special session on AIDS, which is scheduled for May 31 to June 2 in New York City. In addition, the Nigerian President Olusegun Obasanjo, who hosted the summit, urged more donor funding for the three diseases.