Deep Mystery : How Can French Clay Kill Flesh-eating Bacteria?

When the Buruli ulcer, nasty flesh-eating eruptions of Mycobacterium ulcerans, broke out in Ivory Coast a decade ago, two French green clays worked best, removing the specter of surgery or amputation. One clay induced excruciating pain, but in several days it induced skin tissue regeneration on the open wound. A second variety, mixed with shea butter (a plant oil), induced no pain and cured the oozing ulcer in several months. In France, these iron-rich clays have been used for centuries.Now a team led by mineralogist Lynda Williams of Arizona State University (A.S.U.) in Tempe has been attempting to explain the healing powers of the French clays."This clay was unique in that they were very small particle size, 200 nanometers, or 1/400 the width of a human hair," said Williams. The producer companies (Agriletz and Agricur) did not expose the source of the clays, but French mineralogists guess they are made of volcanic ash deposits from the French Massif Central. First tests were made on Escherichia coli, the all-over present food infecting bacteria, but after that on all kinds of bacteria, from Salmonella to antibiotic-resistant Staphylococcus aureus. "That's when we first discovered that the first clay promoted bacterial growth and the second killed it," said Wiliams. "The strains that we are using are the same ones that pharmaceutical companies use to test their antibiotics. All of the gram-negative pathogenic bacteria to humans that we've tested, we can kill completely." said co-author Shelley Haydel, A.S.U. microbiologist. Like many antibiotics, the clay stopped the reproduction of those bacteria it could not kill. "The number of cells we start with is 107 Staphylococcus aureus. After 24 hours, that level reduces tenfold." said Haydel. But the tests have not solved the puzzle: how do they do it? Chemical analysis found no particular minerals or metals in the clay explaining the antibacterial powers and added water did not affect this effect.
The killing powers were preserved even when the clays were heated to over 1,000o F (550o C), but lost over 1,650o F (900o C), when the clay's structure was affected, leaving behind only the heaviest elements, like radioactive cesium, selenium and toxic arsenic. "E. coli can tolerate 200 parts per million and we're talking about 50 ppm. The clay's antibacterial effect appears to be chemical rather than physical, because its strength diminishes as it loses positively charged molecules and it does not smother the bacteria or cause its cell walls to burst. After six hours, you can see a [bacterial cell] surface that is kind of wormy or grainy. It doesn't look like something is precipitating at the surface. Maybe something is going into the cell and damaging it that way." said Williams. The clay could combine the antibacterial powers of its many various elements. "I think these clays are buffering water to keep whatever's toxic to bacteria in there. If we remove the clay from water, I think it's not going to work." said Williams.
The age also affects the clays' power. "We went back and got some from the same batch and it didn't kill. This clay has been sitting outside in a pile for 10 years. It could have oxidized and maybe the oxidation state has affected the antibacterial properties." said Williams. Two other clays with similar antibacterial powers have been detected. "They're all different mineralogically, though they have a general structure in common. We're trying to compare the properties of these antibacterial clays and see what's going on." said Williams. Researchers do not neglect the variant that clays could boost the human immune system reaction to the infection, which M. ulcerans can inhibit. "Even if you removed the antibacterial properties, do the clays have any effect on wound healing? What is the body's response? Are you stimulating tissue regeneration? We already use maggots and leeches in hospitals. Why don't we use clays?" said Haydel.

The Mysterious Crickets of Hawaii

A new study by UC Riverside evolutionary biologists revealed that in only a few generations, cricket (Teleogryllus oceanicus) (photo) males in Kauai island (Hawaii) experienced a mutation that left them incapable of using sexual signal songs to attract females. The new male crickets - even if they lacked the singing apparatus - are able to mate successfully with females. They changed their behavior, surpassing what seemed a harmful mutation increase. More
than 90 percent of male crickets on Kauai changed in less than 20 generations from normal to non singing. The mutation protects male crickets from a deadly parasitic fly (Ormia ochracea) that locates them by using their song. The fly deposits larvae onto crickets; these enter into the cricket, eat it from inside, and subsequently kill the cricket, after that emerge from its body. Of three Hawaiian Islands (Oahu, the Big Island of Hawaii, and Kauai) where both the cricket and fly are found, Kauai has the highest prevalence of the parasitic fly, but also of non singing male crickets. "With each visit we made to Kauai since 1991, we observed fewer crickets," said Marlene Zuk, professor of biology."In 2001, we heard only one calling male. But then in 2003, although we heard none of the male crickets calling, we found they were not only in high abundance but nearly all of them also had female-like wings, lacking the fine structures needed to produce song."Male cricket populations in Oahu and the Big Island - as well as descendants from eggs collected on Kauai before 2003 - continued to show normal wings. Only Kauai displayed mutant male crickets in 2003. "Loss of calling clearly seems to be protecting the male crickets from the deadly fly," Zuk said. "But this protection has a heavy price: the loss of its sexual signal. This is obviously a huge loss for the cricket, akin to, say, finding that all peacocks in a forest have lost their tails. One might ask how then do female crickets locate silent males?"It seems that mutant males behave as 'satellites' to the few remaining male crickets that can call, by congregating near the singing males, and so females find and mate them, as field experiments suggested. "While we were surprised by the extraordinary speed at which the mutation spread, what is more interesting is that, ordinarily, you would expect such a change in wing morphology to quickly disappear, because males couldn't attract mates," Zuk said. "Instead, the behavior of the flatwings allows them to capitalize on the few callers that remain, and thus escape the fly and still reproduce. This is seeing evolution at work."

The Mysteries of Chinese Writing

Chinese writing is thought to have resisted for 4,500 years. And the greatest danger for it was the attempt of replacing it with the Latin script. But this did not work due to ethno-political reasons: while those from the Han ethnic group regard themselves as Chinese proper, they speak 13 different languages (not dialects!), even if amongst them, Mandarin is the most spoken and official. The phonetic Latin writing revealed they cannot understand one another by speech but by their common writing, which makes use of about 5,000 morphemes. Combinations of characters create Chinese words.
From the time of Qin Dynasty (which give the western name of China) onwards, a standard written language has filled the gaps between the various Chinese languages.But now Chinese archaeologists investigating ancient rock carvings claim that they have discovered proofs that modern Chinese script is thousands of years older than people believed. Scientists have detected over 2,000 pictorial symbols, as old as 8,000 years, on cliff faces in the north-west of China. The ancient symbols display a strong similarity to later morphs of ancient Chinese characters. Scholars had thought Chinese symbols came into use about 4,500 years ago. Based on the Damaidi carvings, found in the 1980s, covering 15 sq km (5.8 square miles) and depicting over 8,000 individual figures like the sun, moon, stars, gods and scenes of hunting or grazing, it was believed that the Chinese writing is about 4,500 years old and pottery inscriptions from Henan province (central China) were of similar age . "We have found some symbols shaped like both pictures and characters," Li Xiangshi, a cliff carving expert at the North University of Nationalities in Ningxia Hui autonomous region, told Xinhua news agency. "The pictographs are similar to the ancient hieroglyphs of Chinese characters and many can be identified as ancient characters." To make a comparison, the Greek script is about 3,000 years old. The Latin script, based on the Greek, is even younger, about 2,500 years old. The Arab script is younger, almost 1,500 years old.

The Mysterious Colours Of Autumn Leaves

Every autumn we look in melancholy at the falling leaves. But before falling, the leaves get yellow and orange with shades of red. But why this diversity in the color of the fallen leaves? The undergraduate research project of Emily Habinck at the University of North Carolina at Charlotte, revealed that the color of the autumn leaf was connected to the amount of nutrients in the soil. She found that on a North Carolina
floodplain with a soil abundant in nitrate (a nutrient that delivers nitrogen to the plants), yellow was the dominant color in the autumn "carpet", while the hillside, with poorer soils, were dominated by red during the fall. Even trees with typical red autumn leaves had even redder hues on poorer soils. A 2006 research led by William Hoch, a plant physiologist at Montana State University, connected the synthesis of anthocyanin red pigments in leaves to fall sunlight. "It wasn't until I read his paper that it became a full story," Habinck said. Leaves change color in the fall when trees stop the photosynthesis while withdrawing their nutrients from the leaves to be stored into their roots. "[The tree] pulls as many of these in as it can, then tries to drop just a skeleton of a leaf when it's done", Hoch told National Geographic. But the food withdrawal is not a rapid process, and in the meantime, leaves are left vulnerable to harmful light waves. "Anthocyanins protect leaves by "shading" them from excessive sunlight during the plant's relatively vulnerable autumn season," Hoch explained.Plants genetically engineered not to synthesize anthocyanins could not withdraw as many nutrients from their leaves. "So the bottom line is that the plants that were able to produce red pigments were able to squeeze more of the nutrients out of their leaves than the ones that couldn't. Thus, plants living in nutrient-poor soils benefit more from anthocyanin than those living on better soils.", said Hoch. "Scientists only recently made these connections, because when most other leaf-peepers are taking their fall-color tours, biologists are busy with academics. Most people's field season is in the summer," said Habinck.

The Mysterious Language Of Fish

Fish don’t think/’Cause fish know everything." If we make scuba diving, the sea seems a world of silence. But it’s a deceptive view. Fish are not that smart and …they do speak. In fact, water transmits sounds better than the air and while light penetrates just to 300 m (1,000 ft), below this depth there’s total darkness and the inhabitants of the depths use sounds to ..."keep in touch". Abyssal fish employ sounds for echolocation, in order to detect the relief of the bottom. Amongst the sea dwellers, people are familiar with the song of the whales, that can be "heard" to 80 km (50 mi) away and the humpback
whales for example can sing at intervals of 20 minutes for hours. Cetaceans (whales and dolphins) are also known for their ultrasound echolocation: they emit sounds at 150 kHz that propagate till 3 km (1.6 mi) away, but which cannot be heard by the human ear. In fact, ultra-sensitive submarine microphones can record, in the sea water, rustles, cracks, gasps, gnashes, bangs, sizzles, drumming sounds, ship whistles, croaks, snores. Researches revealed how fishes produce sounds. By gnashing the front teeth emit sounds the seabreams (Sparidae), pufferfishes (Tetraodontidae), porcupinefishes (Diodontidae), sunfishes (Molidae); mackerels (Scombridae) employ the pharyngeal teeth.
Triggerfishes (Balistes), sticklebacks (Gasterosteus), and surgeonfishes (Acanthurus) emit sounds by rubbing their spines. Clownfihes use their jawbones to emit their clacking sounds. Some fishes have muscles that produce vibrations by their contractions. These muscles can be found on the walls of the swim bladder, like in gurnards (Trigla), dories (Zeus), toadfishes (Batrachoididae), shark catfishes (Pangasiidae) or armored catfishes (Callichthyidae) (which emit chirp like sounds). Fish calls can have a social meaning (like in herrings) of "gathering", "danger", or "change direction", or can be territorial, like in clownfishes (Amphiprion).
Seahorses (Hippocampus) emit mating calls. Croaker males (Sciaena) make drumming-like calls to chase away rival males during the mating season. Similar drummings are emitted by the toadfishes (Opsanus). Gurnards scare off predators with their grumbling calls. Pisara (Moenkhausia) – a fish of just 12 cm (5 inch) from the Amazon – emits elephant-like roars, while curbinatas (Plagioscion), also from Amazon, produce shots-like sounds.

The Mystery Of Dolphin's Language

It has already been known that each dolphin population has its own dialect or even "language", which cannot be understood by a "foreigner" dolphin, as it is learned. But a new research made by PhD candidate Liz Hawkins, from Southern Cross University's Whale Research Centre, in Lismore, revealed that the dolphin "speech" is much more sophisticated than previously believed.The three years research was made on bottlenose dolphins off the coast of Byron Bay, NSW (Australia). Focusing on the starting and final frequency of the sound and its length, Hawkins encountered 186 different
whistle types out of 1650 recorded, of which 20 were common. The whistles could be assigned into five classes based on tone, and they were all connected to certain behavior.Socializing dolphins mostly emitted flat-toned or rising-toned whistles. Traveling groups made "sine" whistles: "These could be advertising their pod to other pods. They could be talking to another pod and saying, 'We are over here ... do you want to join?'," said Hawkins.Resting dolphins emitted "concave" whistles, sounds that failed in pitch and get up again, while downward-toned whistles could not be linked to any particular behavior. One class of whistles was connected to feeding."They could be advertising they have found food, they could be advertising to other animals there is food there, or it could be referred to a particular type of feeding or a particular type of food", said Hawkins.Dolphins riding the waves of a boat often emitted a particular sound, while in early investigation made by Hawkins, on a dolphin population of Queensland's Moreton Island, encountered a particular whistle emitted by lone dolphins."That whistle could definitely mean: 'I'm here, where is everyone?'," said Hawkins. She warned that dolphins transmit "context-specific information"."A specialist in linguistics would not call this a language. They are wild animals and generally wild animals only make sounds or transmit information that is essential to their survival. It basically suggests their communication is a lot more complex than what was generally thought."