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February 25, 2014

Researchers identify protein responsible for malaria transmission

Researchers identify protein responsible for malaria transmission

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Tuesday, February 25, 2014

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Plasmodium falciparum gametocytes.

Two groups of researchers have independently identified the the protein responsible for malaria transmission to mosquitoes in studies published in journal Nature on Sunday.

The scientists found a direct relationship between the protein AP2-G’s with malaria gametocytes (male and female sexual forms) production, which is necessary for the transmission. Only the sexual forms infect mosquitoes and sexual reproduction occurs within the mosquito digestive tract.

Malaria is caused by Plasmodium parasites. The initially separate teams looked at different plasmodium species. One, an international group led by Manuel Llinás of Penn State University in the US, examined Plasmodium falciparum, which is responsible for the worst form of human malarial infections; the other, led by UK scientists Oliver Billker from the Wellcome Trust Sanger Institute in England and Andy Waters from University of Glasgow in Scotland, looked at Plasmodium berghei, which infects rodents.

The P. falciparum group was kickstarted by research in Spain which found different organisms from the same strain with identical DNA had varying levels of AP2-G, with a strong correlation to their levels of sexual activity. The more AP2-G, the higher the rate of gametocyte formation. Researchers in England, later also drawn into the international team, analyzed the genomes of two mutated strains of P. falciparum which were both unable to form gametocytes. They found that the gene responsible for producing the AP2-G protein was the only common non-functioning gene.

The international team found found the AP2-G protein catalyzes the transmission by activating a relevant gene set in the parasite.

Women tend to their malaria-infected babies in Angola.
Image: USAID Africa.

Both teams confirmed the finding by gene therapy — both by adding the gene into a mutated strain and observing its ability to form gametocytes, and the other way round.

The parasites exist in a mosquito, then in a human, and require subsequent transmission for the parasite to spread. The transmission can only happen through gametocytes. The parasite triggers formation of the sexual gametocytes into the human’s circulatory system every two days in small quantities — not wasting energy on the process at the dry time of year when few mosquitoes are available — but little was known about the mechanism.

Dr. Oliver Billker commented on the potential of getting the transmission of malaria under control, unlike the existing focus on addressing the phrase causing the clinical symptoms, “Current drugs treat patients by killing the sexless form of the parasite in their blood — this is the detrimental stage of the malaria lifecycle that causes illness. However, it is now widely accepted that to eliminate malaria from an entire region, it will be equally important to kill the sexual forms that transmit the disease.”

The researchers hope to continue research toward drugs to prevent the transmission of the disease. The science was funded by groups including UK research councils, the Spanish government, the U.S. National Institutes of Health, and the European Commission.



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September 27, 2011

Study: Birds learn nest building

Study: Birds learn nest building – Wikinews, the free news source

Study: Birds learn nest building

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Tuesday, September 27, 2011

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According to a recent study, birds learn the skill of building nests during their lifetimes, as opposed to instinctively knowing how to build them. The findings were made by researchers from various universities within Scotland — Edinburgh, St Andrews, and Glasgow.

The researchers examined footage of the Southern Masked Weaver recorded by scientists in Botswana, Africa. The species was picked due to its tendency to build numerous grass nests during the breeding season.

During the study, which had Leverhume Trust funding, it was noted that each individual bird has a tendency to vary their technique in nest building, and that some birds built nests from right to left and some vice versa. The researchers also discovered that as birds gain more experience, they drop fewer blades of grass. This indicates that birds learn how to build nests over time, as opposed to the theory of them being aware of how to perform such a task immediately.

Dr. Patrick Walsh of the University of Edinburgh has explained: “If birds built their nests according to a genetic template, you would expect all birds to build their nests the same way each time. However this was not the case. Southern Masked Weaver birds displayed strong variations in their approach, revealing a clear role for experience. Even for birds, practice makes perfect.”

The study was published in the journal Behavioural Processes.



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September 1, 2010

Study suggests \’sleeping sickness\’ parasite mutated to evade immune system defences

Study suggests ‘sleeping sickness’ parasite mutated to evade immune system defences

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Wednesday, September 1, 2010

File photo of trypanosoma brucei

Research teams from the universities of Georgia and Glasgow discovered the mechanism the Trypanosome parasite evolved for “sleeping sickness” disease to circumvent the human immune system. Their study follows a recent African outbreak of the disease this parasite causes. The discovery is expected to help develop a cure preventing future deaths.

A tsetse fly, generally responsible for the spread of the condition.

The 1998–2001 sleeping sickness epidemics in South Sudan, Angola, Democratic Republic of Congo, and Uganda caused tens of thousands of deaths. The parasites are spread by tsetse flies. It is considered one of the worst epidemics in the last five decades. As WHO reported, subsequent recent introduction of population screening in rural areas and distribution of more effective drugs had potentially reduced the number of death incidents. However, the main effect of these measures being a decrease in spreading of the parasite and not in decrease of the death rate, the researchers decided to tackle the puzzle.

The scientists studied the molecules the human immune system activates in response to the attack. They were looking for the way the parasites inhibit it and lead to the death of the victim. Of the several known parasite species, the two that can infect humans were chosen to study, called Trypanosoma brucei gambiense and Trypanosoma brucei rhodensiense. Several others also exist, but they affect only animals.

Researchers knew that the Trypanosoma attacks typically are repelled by an HDL, more specifically trypanosome lytic factor-1 (TLF-1). It is generated in the humans’ immune system and is toxic to the parasites but not to humans. It was known that one of the parasites, T. b. rhodensiense, has evolved an inhibitor of the toxic chemical, called Serum Resistance Associated (SRA) protein. However the other one, T. b. gambiense, was responsible for over 95% of human deaths, and it had been previously unknown why.

The study showed that a gene mutation has lead to a change in the parasite’s surface protein receptor. It doesn’t bind to TLF-1 as well as for other species, leading to a substantial decrease in TLF-1 uptake by the parasite. The receptor is more strict, causing a lower nutrient intake as well, but it suffices, and the parasite defends against the human immune system.

As professor and head of the department of biochemistry and molecular biology at UGA (and one of the leaders of the research) Stephen Hajduk explained, “Humans have evolved TLF-1 as a highly specific toxin against African trypanosomes by tricking the parasite into taking up this HDL because it resembles a nutrient the parasite needs for survival. But T. b. gambiense has evolved a counter measure to these human ‘Trojan horses’ simply by barring the door and not allowing TLF-1 to enter the cell, effectively blocking human innate immunity and leading to infection and ultimately disease.”

Based on the results of the research, humans could possibly develop a defense mechanism to keep the parasites from evading the human defense system. Stephen Hajduk commented, “We believe this research represents a paradigm shift and causes us to think more broadly about how pathogens avoid host defense mechanisms. It turns out that African trypanosomes have evolved a diversity of ways to avoid human innate and acquired immune systems.”


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August 22, 2010

Scottish poet Edwin Morgan dies at age 90

Scottish poet Edwin Morgan dies at age 90

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Sunday, August 22, 2010

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Scottish poet Edwin Morgan has died at the age of 90. The cause of death was announced as pneumonia. Morgan’s writing career spanned for more than 60 years. He was Scotland’s first national poet, known as the “Scots Makar“. His death was confirmed by his publisher.

Born in Glasgow in 1920, Morgan grew up in Rutherglen. He later returned to his birth town where he studied at Glasgow University in 1937.

Morgan published his first book, The Vision of Cathkin Braes, in 1952. He later began to write experimental poetry. In the early 1960s, Morgan published The Second Life, a book that would boost his career. From Glasgow to Saturn, a collection about space exploration, was published shortly after The Second Life. Both of these books would later be taught in Scottish schools. Later in his career, Morgan received several awards for his work. In 1999, he became Glasgow’s first Poet Laureate, and he was awarded the Queen’s Gold Medal for Poetry a year later. In 2001, he was awarded the Weidenfeld Prize for Translation.

By the time Morgan was named the “Scots Makar” in 2004, he had been diagnosed with cancer and was living in a nursing home. Despite the illness Morgan continued to write, even writing about the disease.

Scotland’s First Minister Alex Salmond paid tribute to Morgan saying that he was “a truly a great man, an exceptional poet, and an inspiration”. He added that “Much-loved in Scotland and indeed around the world, his work tackled all manner of global issues and major historical events closer to home. His passion for observing all aspects of Scottish life shone a spotlight on Scotland for the rest of the world”.



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