Qs people asked em on science and my replies to them - part 183

Q: How can we control elephants that are  destroying our crops?

Krishna: We ourselves are responsible for this behaviour of elephants. We are destroying their home i.e., forests. We are occupying and building things in their pathways. They have no other go but to take over our lands now.

Protecting their habitats is the most important way to keep elephants away from us. 

However, in some countries people are following certain things to keep elephants away from their crops.

Elephants are afraid of bees. Yes, you heard it right. Such big elephants are afraid of small bees. 

Elephants are so terrified of this tiny insect that it will flap its ears, stir up dust and make noises when it hears the buzz of a beehive. Of course, a bee’s stinger can’t penetrate the thick hide of an elephant. But when bees swarm – and bees swarm aggressively – hundreds of bees might sting an elephant in its most sensitive areas, the trunk, mouth and eyes. And they hurt. The threat of bees is so intensely felt by elephants that conservationists are using it to help prevent the kinds of conflict between them and us.

In recent years, researchers and advocates have persuaded farmers to use the elephant’s fear of bees as a potential fence line to protect crops. By stringing beehives every 20 meters – alternating with fake hives – a team of researchers in Africa has shown that they can keep 80 percent of elephants away from farmland.

Asian elephants are also afraid of bees, though perhaps less so. It’s the first step towards showing that the control strategy can also work in countries such as SriLanka, India, Nepal and Thailand, where Asian elephants are 10 times more endangered than their African cousins.

In Africa, Save the Elephants, a nonprofit conservationist group, builds wire and beehive fences at roughly one-fifth the cost of an electrified fence. The farm gets protection against elephants and a modest new source of income from a twice-a-year honey harvest. 

The fences also serve as a psychological barrier for the farmers, making them think twice before slashing and burning more forest for farmland. The beehive fences are being used or tested in some countries in Africa and Asia.

Beehive fence ( Picture source: Google images)

Q: Are there some extreme living things on Earth? 

Krishna: We have extremophiles.  They are organisms that live in "extreme environments," under high pressure and temperature. Bacteria often form on the rocks near the hydrothermal vents. 

Researchers found bacteria in Yellowstone National Park's hot springs too. Bacteria living in the area were thriving at extraordinarily high temperatures. The newly named Thermus aquaticus lived in water that was nearly 212 degrees Fahrenheit (100 degrees Celsius) -- practically boiling!

Since they live in “extreme environments” (under high pressure and temperature), they can tell us under which range of conditions life is possible.

The unique enzymes used by these organisms, called "extremozymes," enable these organisms to function in such forbidding environments. These creatures hold great promise for genetically based medications and industrial chemicals and processes.

It's important to note that these organisms are 'extreme' only from a human perspective. While oxygen, for example, is a necessity for life as we know it, some organisms flourish in environments with no oxygen at all.

­Extremophiles aren't just bacteria. They come from all three branches of the three domain classification system: Archaea, Eubacteria and Eukaroyta (1). 

The microorganism Ferroplasma aci­diphilum ­needs a large amount of iron to survive, quantities that would kill most other life forms.

Then there are Radiotrophic fungi which appear to perform radiosynthesis, that is, to use the pigment melanin to convert gamma radiation into chemical energy for growth. This proposed mechanism may be similar to anabolic pathways for the synthesis of reduced organic carbon (e.g., carbohydrates) in phototrophic organisms, which convert photons from visible light with pigments such as chlorophyll whose energy is then used in photolysis of water to generate usable chemical energy (as ATP) in photophosphorylation or photosynthesis. 

Radiotrophic fungi were discovered in 1991 growing inside and around the Chernobyl Nuclear Power Plant. Research at the Albert Einstein College of Medicine showed that three melanin-containing fungi—Cladosporium sphaerospermum, Wangiella dermatitidis, and Cryptococcus neoformans—increased in biomass and accumulated acetate faster in an environment in which the radiation level was 500 times higher than in the normal environment. Exposure of C. neoformans cells to these radiation levels rapidly (within 20–40 minutes of exposure) altered the chemical properties of its melanin, and increased melanin-mediated rates of electron transfer (measured as reduction of ferricyanide by NADH) three- to four-fold compared with unexposed cells. Similar effects on melanin electron-transport capability were observed by the authors after exposure to non-ionizing radiation, suggesting that melanotic fungi might also be able to use light or heat radiation for growth.

Radiotrophic fungi (Image source: Wikipedia) 

Different names given to extremophiles based on their preferred living conditions ...

• Acidophile: likes acidic environments (low pH)
• Alkaliphile: likes alkaline environments (high pH)
• Anaerobic extremophile: thrives in areas without oxygen; some cannot grow where there is oxygen.
• Cryophile: loves extremely cold temperatures
• Piezophile/barophile: likes high pressures
• Psychrophile: flourishes in low temperatures
• Thermophile: does well in temperatures of 104 degrees Fahrenheit (40 degrees Celsius) or higher
• Hyperthermophile: blooms at temperatures of 176 degrees Fahrenheit (80 degrees Celsius) or higher
• Xerophile: likes environments with little water

NASA found  an extremophile, Deinococcus radiodurans, which is extremely resistant to radiation. This microbe can withstand doses of radiation 500 percent higher than would be lethal to humans (2). Interestingly, the radiation actually does break the microbe's DNA into pieces. But in many cases, the DNA can reassemble and work normally again. It accomplishes this by shedding broken parts of DNA, using a special enzyme to attach good DNA to other still-healthy pieces of DNA, and then creating complementary pieces to­ bond to these newly formed long DNA strands. Understanding how D. radiodurans does this could allow scientists to bring dead cells back to life. For NASA, harnessing this DNA-resistance could offer clues for building better spacesuits or spacecraft.

Q: How can we control weeds using natural techniques?

Krishna: Heard about allelopathy? 

Some plants are very successful in the competition for space, nutrients, and water. They inhibit the growth of their competitors by chemical signals that cause cells of the neighboring plant to die. Scientists are studying this effect for potential use in environmentally compatible bioherbicides.

The phenomenon that no other plants grow near a walnut tree and that wild garlic and mint displace their neighbours. This chemical warfare is referred to as allelopathy by experts.

In most cases, this effect in the target plant is caused by chemical signals rather than poisons. While wild garlic and mint are immune to the effect of their chemcial signals, biological communication triggers self-controlled cell death in the neighbouring plant. Scientists think that this mechanism of plant communication may lead to the development of novel, environmentally compatible bioherbicides that specifically affect a certain type of weed without damaging the useful crop (3).

Q: Why is corona virus spreading so easily by people despite some precautions?

Krishna: There are various reasons. The most important ones are the nature of symptoms. 

Some people are asymptomatic carriers. They don't show any symptoms but spread the disease. 

Recent studies suggest as many as 80% or more of those infected are “silent carriers”, showing no or very mild symptoms.

It seems children and young, healthy people are more likely to be asymptomatic.

And this disease is spread even two days before the symptoms develop (because of high viral load) in people with symptomatic carriers.

Because of this this is being spread very rapidly. That is why WHO says test, test, test, test. 

Testing and isolation are best to control these types of diseases.

Q: Can herd immunity protect us from COVID 19? On person is suggesting that as Indian population is young , we can use herd immunity. What do you think?

Krishna: May be at later stages, not now. 

Just opinions don't count in science. 

References:

1. https://serc.carleton.edu/microbelife/extreme/index.html

2. https://en.wikipedia.org/wiki/Deinococcus_radiodurans

3. https://phys.org/news/2020-04-mint-scent-inhibits-growth-weeds.html...