Category Archives: Life Science

Germany Bans Chemicals Linked to Bee Deaths

Germany bans chemicals linked to honeybee devastation

Germany has banned a family of pesticides that are blamed for the deaths of millions of honeybees. The German Federal Office of Consumer Protection and Food Safety (BVL) has suspended the registration for eight pesticide seed treatment products used in rapeseed oil and sweetcorn.

The move follows reports from German beekeepers in the Baden-WÃ¼rttemberg region that two thirds of their bees died earlier this month following the application of a pesticide called clothianidin. “It’s a real bee emergency,” said Manfred Hederer, president of the German Professional Beekeepers’ Association. “50-60% of the bees have died on average and some beekeepers have lost all their hives.” Tests on dead bees showed that 99% of those examined had a build-up of clothianidin.
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The company says an application error by the seed company which failed to use the glue-like substance that sticks the pesticide to the seed, led to the chemical getting into the air.

Darwin’s Orchid Prediction

American Museum of Natural History:

Darwin first saw this astonishing orchid from Madagascar, Angraecum sesquipedale, in 1862. Its foot-long green throat holds nectar—the sweet liquid that draws pollinators – but only at its very tip. “Astounding,” Darwin wrote, of this strange adaptation. “What insect could suck it?” He predicted that Madagascar must be home to an insect with an incredibly long feeding tube, or proboscis. Entomologists were dubious: no such insect had ever been found there.

Life Far Beneath the Ocean

Huge hidden biomass lives deep beneath the oceans

Recently, he and his colleagues examined samples of a mud core extracted from between 860 metres and 1626 metres beneath the sea floor off the coast of Newfoundland. They found simple organisms known as prokaryotes in every sample. Prokaryotes are organisms that often have just one cell. Their peculiarity is that, unlike any other form of life, their DNA is not neatly packed into a nucleus.
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Where cells living so far beneath the sea floor could have come from remains a mystery. They may have been gradually buried in sediment as millions of years passed by, and adapted to the increasing temperatures and pressure, he says.

Another possibility is that they were sucked deep into the mud from the sea water above. Hydrothermal vents pulse hot water out of the seabed and into the ocean. This creates a vacuum in the sediment, which draws fresh sea water into the marine aquifer.

It is important to understand the way the cells got down there, because that has implications for their age. The cells are not very active and according to Parkes they have very few predators. “We find very few viruses, for example, down there,” he says. “At the surface, if you don’t divide you get eaten. But if there are no predators, the pressure to reproduce decreases and you can spend more energy on repairing your damaged molecules.”
Ancient life

This means it is conceivable – but unproven – that some of the cells are as old as the sediment. At 1.6 km beneath the sea, that’s 111 million years old. But in an underworld where cells divide excruciatingly slowly, if at all, age tends to lose its relevance, says Parkes.

More very cool stuff, this stuff is fun.

The Subtly Different Squid Eye

The subtly different squid eye by PZ Myers:

the inside out organization of the cephalopod eye relative to ours: they have photoreceptors that face towards the light, while we have photoreceptors that are facing away from the light. There are other important differences, though, some of which came out in a recent Nature podcast with Adam Rutherford, which was prompted by a recent publication on the structure of squid rhodopsin.

Superficially, squid eyes resemble ours. Both are simple camera eyes with a lens that projects an image onto a retina, but the major details of these eyes evolved independently – the last common ancestor probably had little more than a patch of light sensitive cells with an opsin-based photopigment. The general properties of this ancient eye can still be seen in modern eyes. They detect light with a simple molecule called retinal that is capable of absorbing a photon, changing its shape from the 11-cis form to the all trans form; basically, it flips from a chain with a kink to a straight chain. Retinal is imbedded in a protein called opsin. When retinal changes shape, it changes the shape of the opsin protein, too, which can then interact with other proteins in the cell membrane.

The next protein in the sequence is called a G protein. G proteins are ubiquitous intermediates for many cellular processes; when a receptor, like opsin, is activated, it activates a G protein, which then activates other proteins, starting a signaling cascade. In the podcast, I compare this to starting an avalanche. Opsin is an agent standing on a hill; when it receives a light signal, it nudges a small boulder (the G protein), which then tumbles down setting a whole series of rocks in motion. The G protein is an intermediate which takes a small change, the initial nudge, and amplifies it into the activation of many other proteins.

Running Out of Fish

I have posted before about the overfishing problems: Fishless Future – SelFISHing – Chinook Salmon Vanish Without a Trace. Here is an emotional article on the problem – How the world’s oceans are running out of fish

Ninety years of industrial-scale exploitation of fish has, he and most scientists agree, led to ‘ecological meltdown’. Whole biological food chains have been destroyed.
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In 2002, the year an EU report revealed that the Senegalese fish biomass had declined 75 per cent in 15 years, Brussels bought rights for four years’ fishing of tuna and bottom-dwelling fish on the Senegal coasts, for just $4m a year. In 2006, access for 43 giant EU factory fishing vessels to Mauritania’s long coastline was bought for Â£24.3m a year. It’s estimated that these deals have put 400,000 west African fishermen out of work; some of them now take to the sea only as ferrymen for desperate would-be migrants to the Canary Islands and Europe.
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Protecting up to 40 per cent of the world’s oceans in permanent refuges would enable the recovery of fish stocks and help replenish surrounding fisheries. ‘The cost, according to a 2004 survey, would be between Â£7bn and Â£8.2bn a year, after set-up. But put that against the Â£17.6bn a year we currently spend on harmful subsidies that encourage overfishing.’
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The Newfoundland cod fishery, for 500 years the world’s greatest, was exhausted and closed in 1992, and there’s still no evidence of any return of the fish. Once stocks dip below a certain critical level, the scientists believe, they can never recover because the entire eco-system has changed.

Curious Platypus Genome is No Surprise

Platypus Genome Found Fittingly Strange by Rick Weiss

a team of scientists has determined the platypus’s entire genetic code. And right down to its DNA, it turns out, the animal continues to strain credulity, bearing genetic modules that are in turn mammalian, reptilian and avian.

There are genes for egg laying — evidence of its reptilian roots. Genes for making milk, which the platypus does in mammalian style despite not having nipples. Genes for making snake venom, which the animal stores in its legs. And there are five times as many sex-determining chromosomes as scientists know what to do with.

“It’s such a wacky organism,” said Richard Wilson, director of the Genome Sequencing Center at Washington University in St. Louis, who with colleague Wesley Warren led the two-year effort, described today in the journal Nature.

Yet in its wackiness, Wilson said, the platypus genome offers an unprecedented glimpse of how evolution made its first stabs at producing mammals. It tells the tale of how early mammals learned to nurse their young; how they matched poisonous snakes at their venomous game; and how they struggled to build a system of fertilization and gestation that would eventually, through relatives that took a different tack, give rise to the first humans.

“As we learn more about things like platypuses,” Wilson said, “we also learn more about ourselves and where we came from and how we work.”

Very cool stuff. Related: Platypus genome explains animal’s peculiar features; holds clues to evolution of mammals – Platypus genome mapping boon for human and livestock researchers – Platypus genetic code unravelled – Weird Creatures – Evolution is Fundamental to Science – Long-Eared Jerboa – Cat Joins Exclusive Genome Club – Your Inner Fish

Elephants Classify Human Ethnic Groups that Hunt Them by Odor

Wash Your Clothes: Elephants Can Smell You a Mile Away

…in Amboseli National Park in Kenya. Elephants in the region encounter different ethnic groups, including the Maasai, whose young men spear elephants, and the Kamba, agricultural villagers who pose no threat at all.

The researchers observed elephants exposed to the scent from identical cloth garments, some worn by Maasai men, others by Kamba men and some that were unworn. The Maasai scent produced the strongest reactions, with elephants moving farther and faster to distance themselves from the odor source, often not stopping until reaching tall grass. The elephants also took far longer to calm down than those exposed to scents from the Kamba and unworn cloths.

Breastfeeding Linked to More Intelligent Kids

McGill study links breastfeeding to increased intelligence

The largest randomized study of breastfeeding ever (14,000 children for 6.5 years) conducted reports that breastfeeding raises children’s IQs and improves their academic performance, a McGill researcher and his team have found.

“Our study provides the strongest evidence to date that prolonged and exclusive breastfeeding makes kids smarter,” said Kramer, a Professor of Pediatrics and of Epidemiology & Biostatistics in the McGill University Faculty of Medicine and lead investigator in the study.

Kramer and his colleagues evaluated the children in 31 Belarusian hospitals and clinics. Half the mothers were exposed to an intervention that encouraged prolonged and exclusive breastfeeding. The remaining half continued their usual maternity hospital and outpatient pediatric care and follow-up. This allowed the researchers to measure the effect of breastfeeding on the children’s cognitive development without the results being biased by differences in factors such as the mother’s intelligence or her way of interacting with her baby.

The children’s cognitive ability was assessed by IQ tests administered by the children’s pediatricians and by their teachers’ ratings of their academic performance in reading, writing, mathematics and other subjects. Both sets of measures were significantly higher in the group randomized to the breastfeeding promotion intervention.

“The effect of breastfeeding on brain development and intelligence has long been a popular and hotly debated topic,” says Dr. Kramer. “While most studies have been based on association, however, we can now make a causal inference between breastfeeding and intelligence – because of the randomized design of our study.”

Molecular Action May Help Keep Birds on Course

Four decades after scientists showed that migratory birds use Earth’s magnetic field to orient themselves during their seasonal journeys, researchers have at last found a molecular mechanism that may explain how they do it.

If the hypothesis is true, the planet’s magnetic field lines — which arch around Earth from north to south — may be plainly visible to birds, like the dashed line in the middle of a road.

The work, described online yesterday in the journal Nature, was conducted in a test tube and does not prove that birds actually use the mechanism. And researchers aligned with a competing model say they are not convinced.

But by identifying for the first time a molecule that reacts to very weak magnetic fields, the experiments prove the plausibility of a long-hypothesized method of avian navigation that has had a credibility problem because no one had ever found a molecule with the required sensitivity.

Fat Cell Count Set in Childhood

Fat cell number is set in childhood and stays constant in adulthood

As fat people have an abundance of fat tissue, the natural assumption is that fat people have more fat cells, or ‘adipocytes’. That’s only part of the story – it turns out that overweight and obese people not only have a surplus of fat cells, they have larger ones too.
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During adulthood, about 8% of fat cells die every year only to be replaced by new ones. As a result, adults have a constant number of fat cells, even those who lose masses of weight. Instead, it’s changes in the volume of fat cells that causes body weight to rise and fall.
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we couldn’t have a clearer indication of the importance of childhood as a window for preventing obesity and the chronic diseases affected by it – cancer, heart disease, diabetes and more.

The message is especially stark following the recent Foresight report, which estimated that if current trends are left unchecked, by 2050 a quarter of all UK children under the age of 16 will be obese. The knowledge that their fat cell count will then be set for life makes the cost of inaction even higher. Fortunately, it seems that the UK Government is taking appropriate steps and recently pledged over a third of a billion pounds on a concerted strategy to tackle childhood obesity.