Category Archives: Life Science

Bacteria “Feed” on Earth’s Ocean-Bottom Crust

Once considered a barren plain dotted with hydrothermal vents, the seafloor’s rocky regions appear to be teeming with microbial life, say scientists
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“Initial research predicted that life could in fact exist in such a cold, dark, rocky environment,” said Santelli. “But we really didn’t expect to find it thriving at the levels we observed.” Surprised by this diversity, the scientists tested more than one site and arrived at consistent results, making it likely, according to Santelli and Edwards, that rich microbial life extends across the ocean floor. “This may represent the largest surface area on Earth for microbes to colonize,” said Edwards.
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Santelli and Edwards also found that the higher microbial diversity on ocean-bottom rocks compared favorably with other life-rich places in the oceans, such as hydrothermal vents. These findings raise the question of where these bacteria find their energy, Santelli said.

“We scratched our heads about what was supporting this high level of growth,” Edwards said. With evidence that the oceanic crust supports more bacteria than overlying water, the scientists hypothesized that reactions with the rocks themselves might offer fuel for life.

Why doesn’t this stuff make the news over what some celebrity did or politician said… (well I must admit I am just guessing since I don’t actually watch the news or read the mass media much – other than some science, investing or economics content). Oh well, at least you get to read the Curious Cat Science blog and find out about some of the cool stuff being learned every day.

Learning from Leprosy Diagnosis

A Scary Diagnosis Hits Home

The diagnosis that ultimately resulted — leprosy — turned the Blanchards’ world upside down and rippled through the lives of many people they knew or had contact with. It also raised issues that are often confronted when any contagious disease is diagnosed, particularly one with scary connotations: What precautions should be taken to protect the rights of the affected individual as well as the health of the community?
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For the Blanchards, some of the answers lay almost literally in their back yard. Baton Rouge is home to the National Hansen’s Disease (Leprosy) Clinical Center, part of the U.S. Public Health Service.
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About 300,000 new cases of leprosy are diagnosed annually, according to the World Health Organization. Now known as Hansen’s disease, after the Norwegian scientist who discovered the mycobacterium that causes the illness, it affects about 2 million to 3 million people worldwide.

Where it is left untreated, Hansen’s disease is a leading cause of disability and devastating deformity. It remains endemic in Bangladesh, India, Brazil and elsewhere. In the United States, roughly 6,000 people have the disease. One hundred to two hundred new cases are reported annually, and, like BB Blanchard, about two dozen of those new patients have never been beyond U.S. borders.
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How transmission occurs is a mystery. Humans and the armadillo are the only two creatures known to get the disease. No one knows where the microbe hides in nature, although the suspicion is that the leprosy mycobacterium may be airborne like its bacterial cousin, tuberculosis.

Most people think of leprosy as a skin disease. But the rash that BB Blanchard had and the disfiguring lesions often associated with it are just a symptom. The mycobacteria burrow into nerves, where they often remain undetected for years or even decades.

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.”