Tag Archives: mucus

For 30 years, scientists were unaware of this air-breathing eel hidden by mucus

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In 1836, European scientists discovered a unique animal in the Amazon River. It resembled an eel, was a few feet long, and had lungs filled with air, leading anatomists to believe it was a reptile.

A year later, another specimen was found in Africa and initially declared an amphibian based on its heart structure. After 30 years of debate, scientific consensus concluded that they were fish, breathing air through lungs rather than gills. Thus, the lung fish was identified.

In situations where they cannot access the water’s surface to breathe, West African lung fish (Protopterus Annectens) have the ability to do so. Their tiny eggs do not provide enough oxygen, but these lung fish have adapted to survive in swamp and river environments, enduring seasonal changes.

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Lung fish create burrows in mud, forming mucus-filled chambers where they remain motionless without eating until the rains return, entering a dormant state. This survival tactic can last for several months in the wild, with some lung fish reported to have stayed dormant for up to four years.

The evolution of lung fish dates back over 400 million years, yet many mysteries still surround these creatures, particularly regarding their lung connections to other fish-like features.

Various fish species, such as Bitile and Bow Fin, possess lungs but lack swim bladders. The question of which organ evolved first remains unresolved, highlighting the complexities of evolutionary biology.

Pulmonary fish are often considered the closest living relatives of amphibians -Credit: Albert Guerello

In fish embryos, both swim bladders and lungs develop from intestinal pockets, suggesting a shared evolutionary link. Research indicating a blood system connection further supports the theory that lungs may be older organs than swim bladders, which likely developed later and underwent revisions.

Scholars have long debated whether lung fish, as some of the oldest living fish species, represent a common ancestor linking all vertebrates, including mammals, birds, reptiles, and amphibians.

Another enigmatic group, the coelacanths, are closely related to lung fish in recent studies, but share a closer link to bony fish like tuna and herring than to terrestrial vertebrates such as humans.

There are currently six species of lung fish in existence, with four originating from Africa. The Australian lung fish, known as Metosera, holds the title of the oldest living fish in captivity, with individuals like Grandad in Chicago’s aquarium reaching ages of over 100 years.

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Source: www.sciencefocus.com

Doctors advise against coughing up mucus while sick – here’s why

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There is a common misconception that mucus and phlegm are harmful to the body and should be expelled. However, mucus actually serves as a protective barrier between our body and the outside world.

Just like flypaper, mucus covers the moist surfaces of our nose, sinuses, and lungs to filter out harmful substances we inhale. It consists mostly of water along with proteins, sugars, and molecules that help control harmful bacteria. Therefore, there is no need to get rid of it as it forms a protective layer.

We constantly produce mucus, but it goes unnoticed most of the time. Microscopic hairs called cilia push it back into the throat, and we unconsciously swallow it. Only when excess mucus is produced during illness does it become more noticeable.

When we are sick, the mucus becomes thicker and stickier, but it still plays an essential role in trapping bacteria, viruses, and cells involved in the immune response. So, it is generally best to let the mucus do its job without interfering.

While removing mucus may not provide immediate relief, excess mucus can be uncomfortable. Maintaining moist air, using saline irrigation, gargling with salt water, and staying hydrated can all be beneficial. Nasal decongestants from pharmacies can also help, but should not be used for more than a week to avoid worsening nasal congestion.

In conclusion, there is no need to remove mucus, and doing so will not speed up recovery. However, if it makes you feel better, there is no harm in clearing it.

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Asked by: Daniel Grant, Sunderland

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Source: www.sciencefocus.com

Clownfish produce a sugary mucus to protect themselves from the stings of sea anemones they live in.

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Clownfish and sea anemones have a symbiotic relationship

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The secret is in the runny nose. Chemical changes in the mucus that coats the clownfish’s body can blunt the sting of its symbiotic sea anemone.

Researchers have long suspected that something special in the mucus of the clownfish, also known as the clownfish, protects it from the microscopic stingers of the sea anemone’s tentacles. But the exact mechanism remained a mystery, he said. karen burke da silva At Flinders University, Australia.

To investigate, she and her colleagues bred orange clownfish (Amphiprion percula) and bubble tip sea anemone (Entacmaea four colors) at the Institute. Some fish and sea anemones live in pairs, while others live separately. The researchers collected mucus samples from the fish at various times before and after they had adapted to the anemone, and then placed the mucus on a microscope slide and pressed it against the anemone’s tentacles.

Sea anemones sting by firing small coiled venomous harpoons explosively from their stinging cells called stinging cells. The researchers used a microscope to count and compare the number of stinging cells that fired during the mucus treatment. They found that mucus from a clownfish’s partner, but not mucus from an unknown fish, reduced the firing of stinging cells.

To find out why, the researchers analyzed how the glycans (chains of sugar attached to proteins) and fats in the clownfish’s mucus change as they adapt to their hosts. Three weeks after the symbiotic partnership began, the chemical profile of the mucus changed significantly. In particular, the concentrations of seven types of glycans were changed. Removing glycans or otherwise tweaking them could be one way he suppresses line cell firing, Burke da Silva says.

Alonso Delgado At Ohio State University, the sea anemone shrimp (Ansiromenes Magnificus), using similar glycan methods or evolving different strategies to thwart sting.

Additional strategies may also be at work for clownfish. Glycan changes are slow, and after a partner splits, he grows back within a day. Instead, fish may use an unknown chemical strategy at the very beginning to gain initial access to sea anemones.

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Source: www.newscientist.com