1 Tahrcountry Musings: August 2010

Sunday, August 29, 2010

Bugs and the art of using bifocals

University of Cincinnati researchers have reported the discovery of a bug with bifocals in the latest issue of journal Current Biology.

The two eyes of larvae of sunburst diving beetle (Thermonectus marmoratus) have bifocal lens which amazed the scientists. Using two retinas and two distinct focal planes that are substantially separated, the larvae can more efficiently use these bifocals.  This enables them to see and catch their prey efficiently. They lose these intricate lenses when they become a beetle.

The scientists first used a microscope to look through the lenses of the two eyes detailed in the research article. They discovered how the lens could make a second image grow sharper. This is something that could only happen with a bifocal. Their findings were confirmed with more research in addition to observing the lens and the two focal planes via a microscope. They saw the bifocal again when they used a method to project a narrow light beam through the lens. This could only be explained by a truly bifocal lens.

The discovery could have uses in imaging technology. The bug inspired imaging devices could be round the corner. The discovery also highlights the importance of conserving our biodiversity.

Friday, August 27, 2010

Banana to the rescue of Crohn's disease patients

Crohn's disease causes chronic intestinal inflammation, leading to pain, bleeding and diarrhoea. People with Crohn's disease have increased numbers of a 'sticky' type of E. coli which weakens the ability to fight off invading intestinal bacteria. The sticky E. coli are capable of penetrating the gut wall via special cells, called M-cells. M-cells act as the ‘gatekeepers’ to the lymphatic system. In patients with Crohn's disease this results in chronic inflammation of the gut.

Scientists of Liverpool Biomedical Research Centre (BRC) have found that plantain’s soluble fibers prevented the uptake and transport of E. coli across M.cells. They compared these results with tests on polysorbate-80 – a fat emulsifier used in processed food to bind ingredients together. The tests revealed that polysorbate had the opposite effect to plantain fibres, and encouraged the movement of bacteria through the cells.

According to Dr Barry Campbell, the research has shown that different dietary components can have powerful effects on the movement of bacteria through the bowel. We have known for some time the general health benefits of eating plantain and broccoli, which are both high in vitamins and minerals, but until now we have not understood how they can boost the body's natural defences against infection common in Crohn's patients. The research suggests that it might be important for patients with this condition to eat healthily and limit their intake of processed foods.

Researchers are working with biotechnology company, Provexis, to test a new plantain based food product that could treat patients with Crohn’s disease.

Thursday, August 26, 2010

Unravelled - The Anti-freeze Mechanism of Arctic Fish

I have always wondered why the fish in the arctic region do not freeze. Temperature of minus 1.8 ° C is enough to freeze any fish. The freezing point of fish blood is estimated to be about minus 0.9 ° C.  Research led by Prof. Dr. Martina Havenith (Physical Chemistry II of the RUB) and her team has finally unraveled the mystery.

It is a known fact that there are special frost protection proteins in the blood of arctic fish. How they work was a mystery.

Dr. Martina Havenith and team used a special technique, terahertz spectroscopy, to unravel the underlying mechanism. With the aid of terahertz radiation the researchers were able to show that water molecules, which usually perform a permanent dance in liquid water, and constantly enter new bonds dance a more ordered dance in the presence of proteins. This is the key behind the anti-freeze. This effect is more pronounced at low temperatures than at room temperature.

The mechanism devised by nature using anti-freeze proteins, works far better than any household antifreeze.

Details of the research appear in the latest issue of the Journal of the American Chemical Society (JACS).

Friday, August 20, 2010

Stealth Hunters of Dusk

We have heard of stealth aircrafts that zooms in on target undetected. Here comes an equivalent from the nature world.

Researchers from the University of Bristol have discovered that barbastelle bats hunt moths using stealth technique.

Moths can usually hear bat echolocation signals and take evasive action to avoid being eaten. They have sensitive ears that pick up ultrasonic bat sounds.

Barbastelle bats produces echolocation calls up to 100 times quieter than those of other bats to hoodwink the moths. Moths can detect other bats more than 30 metres away, but the barbastelle gets as close as 3.5 metres using its modified echolocation calls. The bat zoos in before the moth becomes aware of the approaching bat.

Thursday, August 19, 2010

Like Human Beings Bees like a warm Drink on a Cold Day

I was fascinated to read about the preferences of bees for a hot drink on a cold day and vice versa cold drink on a hot day. The info is the outcome of study by insect scientists Drs Melanie Norgate and Adrian Dyer shows of Monash University.

As part of the research, on a cold day the researchers presented artificial flowers with nectar-like liquids that were warmer than the ambient temperature. At ambient temperatures of 23-30°C bees displayed a marked preference for feeding from artificial flowers which were warmer. Warmth along with nectar was an important component in the scheme of things.

Next the researchers measured the body temperature of bees after they had ingested warm nectar. It was noticed that warm nectar helped bees maintain a body temperature of 30-34°C which the researchers think is likely to be required by insects to maintain active flight.

The researchers now plan to investigate how the plants modify the temperature of their flowers to present rewards to pollinating insects. This modulation could be an important factor in the the distribution of flowers in different regions
Details of the research appears in the latest issue of journal PLoS One.

Sunday, August 08, 2010

No update for 10 days

 For the next 10 days I am not in a position to access internet. So there won't be any update during this period

Tuesday, August 03, 2010

The Riddle Cracked - Why in Some Species of Spiders the Males are much smaller than Females

In some species of spiders the males are much smaller than females. Till now no satisfactory explanation was in place for this riddle. Now a Spanish research team headed by Dr Guadalupe Corcobado from the Spanish National Research Council's Arid Zones Research Station in Almeria has come up with an explanation.

The researchers say evolution favours small, light males as it gives them the ability to traverse thin strands of silk. Smaller size also ensures more mating opportunities. Large females are favoured because they reproduce more abundantly. In some species females are more than 12 times longer than males.

Plant dwelling spider produce strands of silk and allows the wind to carry one end of it. When the silk strand lands on a leaf or stem the spider pulls it tight and secures the near end. It then crawls across hanging upside down from the strand. Smaller sized males were very successful in bridging.

The link to bridging is a new concept derived by the Spanish researchers.

Details appear in the journal BMC Evolutionary Biology.