Category Archives: Science

Environment, Research, Science

Natural Environment: How we’ve lost 600 plant species

PLANT EXTINCTIONS

ALMOST 600 plant species have vanished in the past 250 years – potentially robbing science of new medicines.

The figure is more than two-and-a-half times the number of birds, mammals and amphibians that have become extinct.

Around two species of plant are lost forever each year – although, according to research, the true figure is likely to be even higher than that as plants could be disappearing before they are even discovered.

Scientists from the Royal Botanic Gardens at Kew and Stockholm University analysed extinction records worldwide to arrive at the figure.

Species include the Chile sandalwood, a tree that grew on the Juan Fernandez Islands between Chile and Easter Island and was heavily exploited for its scent.

Another is the St Helena olive. One lone tree survived until 1994 but two others propagated from cuttings succumbed to a termite attack and fungus in 2003.

Recent research, published in Nature, Ecology & Evolution, found that 571 plants have disappeared in the past 250 years – four times more than thought. In contrast, a total of 217 of bird, mammal and amphibian species are thought to have become extinct over the same period.

Dr Aelys Humphreys, of Stockholm University, said: “Most people can name a mammal or bird that has become extinct, but few can name an extinct plant.

“This is the first time we have an overview of what plants have already become extinct, where they have disappeared from, and how quickly this is happening.

“Many extinct plants were so poorly understood that we do not even know what their exact roles in nature were, or whether they may have been useful for production of future food or medicine.”

The scientists found that extinctions could be happening 500 times faster than the “natural” background rate – normal losses without human intervention.

Many plants have vanished because of changes of land use, which remains a threat to other surviving species.

Co-author Dr Eimear Nic Lughadha, from Kew, said: “Plants provide the oxygen we breathe and the food we eat, and makeup the backbone of the world’s ecosystems – so plant extinction is bad news for all species.”

. Recommended (Forbes) UN Report: 1 Million Animal And Plant Species At Risk Of Extinction

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Arts, Books, History, Science, Scotland

Book Review: Green Gold

BOOK REVIEW

Green Gold by Gabriel Hemery is published by Unbound. It is the story of a brave Scottish botanist who fell of the edge of the world without a trace.

Intro: In 1850 young Scottish plant hunter John Jeffrey is despatched by an elite group of Victorian subscribers to seek highly-prized exotic tree and plant species in North America. An early letter home tells of a 1,200-mile transcontinental journey on foot.

IN Victorian times, plant-hunters were the astronauts of their age. They captured the popular imagination as they set off on exotic expeditions to discover new flora and fauna.

Like space travel today, these excursions were fraught with danger.

When 23-year-old John Jeffrey left his native Scotland for the Pacific coast of North America in 1850, he would have been familiar with the fate of his compatriot David Douglas 16 years earlier. The man, after whom the Douglas fir was named, perished when he fell – or likely was pushed – into a bull-pit in Hawaii.

At least we know what happened to him. For poor Jeffrey, however, who was last seen in San Francisco in 1854, disappeared without a trace. In this captivating book, forest scientist Gabriel Hemery offers the most informed speculation about his fate. Jeffrey kept diaries, now lost. So Hemery, who probably knows more about Jeffrey than anyone alive, has used his extensive research to fictionalise them.

They are interspersed with actual letters and other documents, which record that Jeffrey was despatched to North America thanks to a Victorian version of crowdfunding.

Shares in his expedition cost £5 each, and the list of 140 subscribers reads like a Who’s Who of high society, all looking to enhance their hothouses with the exotica he sent home. Their investment reaped some dividends. Visitors to the Royal Botanic Gardens in Edinburgh can now see the vibrant pink bloom Dodecatheon jeffreyi, also known as Jeffrey’s shooting star, which he found in California.

Jeffrey, a botanist hired by the keeper of that very garden, had never even been out of Scotland before, but soon found himself embarking on the Hudson’s Bay Company ship, the Prince of Wales.

He was tasked with getting across Canada to Vancouver Island, and then down through Washington state, Oregon and California and as far down as Mexico.

His instructions were clear: ‘You will collect seeds of all such trees, shrubs and plants as are not already introduced into this country.’ They wanted him to send back beetles, too. His remuneration was fixed at £80 per annum.

He arrived in Canada in August 1850. He made the long trek west by dogsled and canoe, then crossed the Rocky Mountains on foot. It took him another 12 months to reach the Pacific coast.

In November 1851, a box sent by Jeffrey was excitedly opened in Edinburgh, by members of the Oregon Botanical Association. It contained a few varieties of pine cone, several dead birds, and a small bottle containing beetles. They were underwhelmed.

Jeffrey’s reputation back home seems to have gone steadily downhill after that. He kept sending boxes, but they didn’t contain enough seeds for the Association’s liking. And Jeffrey’s letters and correspondence got fewer and briefer. One tersely explained that, while camping, most of his seeds had been eaten overnight by a rat.

At that time, the California Gold Rush was in full swing. It could well have been that Jeffrey, disillusioned with the comments from Edinburgh, decided that the earth held far more alluring treasures than plants. Hemery’s research has uncovered other possibilities: Jeffrey simply fell in love and absconded, maybe with a Native American woman, and settled down. Or that he was robbed and murdered.

What we know for sure is that Jeffrey’s letters dried up altogether and there were no more sightings of him, to the fury of his paymasters. In March 1854, they decided to relieve him of his duties, even though he had effectively beaten them to it.

The Association’s minutes record little appreciation of what Jeffrey had sent home, yet that amounted to at least 400 plant specimens and the seeds of 199 species.

No attempts were made to find him. But this fascinating book now helps to ensure that he is remembered for his achievements, and not simply for going missing.

– Green Gold by Gabriel Hemery is published by Unbound for £10.99, 280pp

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Medical, Research, Science

Will we ever develop a vaccine for HIV?

MEDICAL SCIENCE

Intro: In 1983, HIV (human immunodeficiency virus) was found to be the cause of a range of conditions collectively known as AIDS (acquired immune deficiency syndrome). Over 35 million people have since died due to HIV, and the same number live with it.

THE high number of HIV cases and deaths worldwide is in part because the antiretroviral drugs that have been available since the mid-1990s, allowing infections to be managed, are not always widely available in certain parts of the world – namely in Africa, where HIV infection rates are the highest. But also, unlike many other viral diseases, attempts to develop a vaccine for HIV have so far been unsuccessful.

Vaccination against a variety of infectious diseases is now such a routine part of healthcare that it is easy to forget how important it has been in the history of medical science. Many millions of deaths have been prevented since the principles of vaccination were established by the English physician Edward Jenner in the late eighteenth century. Jenner had become aware of local knowledge near his home in Gloucestershire; milkmaids who had previously caught cowpox, a relatively mild disease, did not then suffer from the similar but much more serious, and potentially fatal, smallpox. Jenner conducted trials in which he exposed people to cowpox and some weeks later to smallpox, finding that the more serious and virulent form of the disease did not develop as predicted. It represented the beginning of a long process, which culminated in 1979 when, after a decades-long programme of vaccination, the World Health Organisation (WHO) was able to announce that smallpox had been completely eradicated.

The Success of Vaccines

Great advances in our understanding of how vaccines work was made in the late nineteenth and early twentieth centuries by, among many others, Louis Pasteur, Robert Koch and Paul Ehrlich (the German physician and not the American environmentalist of the same name associated with the study of global population growth). The way in which the immune system works – through the production of antibodies – was discovered, and methods of producing vaccines extended from Jenner’s use of a related mild disease to the use of killed or weakened forms of the original infectious agent, allowing vaccines for a greater range of diseases to be developed. Vaccines were developed for one infectious disease after another, perhaps most famously including the vaccine for polio, developed in 1955 by the American virologist Jonas Salk.

The Trouble With HIV

In among the remarkable successes, vaccines for a few infectious diseases remain frustratingly out of reach. HIV has the ability to evolve quickly, making it difficult to produce a vaccine that will be – and will remain – effective against all the different strains. A further complication arises because it initially evolved to attack the immune system, which has given the virus a complicated surface structure that enables it to evade detection. Vaccines work by stimulating what is known as the adaptive immune system, the part of the system that can remember the structure of pathogens, so that when these are encountered again the immune response will be enhanced. In the case of HIV, the usual ways of producing a vaccine do not work because it is not detected in the first place, so the immune system is not stimulated.

As if the problem of producing a vaccine was not already complicated enough, further difficulties arise because the two usual methods for producing active agents for vaccines have not worked for HIV. Most vaccines have been developed using either a killed or deactivated (attenuated) version of the pathogen, so that it stimulates the immune system without causing harm. HIV that has been killed does not stimulate an immune response, while the complex structure of the virus means that attempting to deactivate it is difficult. Using an attenuated version would run the risk of infecting the patient.

A formidable range of obstacles still exists, but over 30 years of research have provided medical researchers with a huge body of knowledge on HIV, leading many scientists to be optimistic about a future cure. In the meantime, advances in the management of the disease mean that those with HIV, with access to the relevant drugs, can expect to lead an almost normal life. Until a vaccine is found, the challenge remains to extend these treatments to as many people as possible.

Alternative Theories

HIV suppresses the immune system by invading and attacking T cells, which play a crucial role in what is known as cell-mediated immunity. It was thought that, once the virus had invaded a T cell, it replicated and then spread to other T cells through the blood. Recent research has found that it can actually spread much more quickly, by utilising short-lived connections between T cells in order to transfer directly from one cell to another. This may help to explain why those vaccines developed so far have not been very effective, because these have only worked against HIV in the blood, and it may also open up the possibility of new forms of treatment that in some way block this cell-to-cell transmission.

Recommended/Supplementary Reading:

. National Geographic: Ancient “Giant Virus” Revived From Siberian Permafrost

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