Australian Science Illustrated – Issue 51 2017

66 | SCIENCE ILLUSTRATED

Scientists find it difficult to place slime moulds in the right

category of life. The organism is neither an animal, nor a

plant or fungus, but is made up of one large cell with many

nuclei or growth centres linked to the main cell via a network

of tubular structures. The monocellular life form has surprised

scientists by showing signs of intelligence, when in search

of food. Placing bait at the exits, Japanese scientists have

made a slime mould find the shortest way out of a maze.

The natural habitat of zebrafish is the Ganges river in India, but

the species also thrives in many labs. It is popular among

scientists, as it is robust and easily breeds in captivity. The early

embryonic stages of the fish are almost transparent, allowing

scientists to study cells inside the fish, while it is alive. Unlike

other test animals, biologists do not have to kill the animal to

study its cells, and so, the zebrafish is used as a model for cell

development and the function of genes in humans.

Skin neurons are nerve cells that are

characterized by the fact that they communicate

via electrical or chemical signals. The long green

threads in the image are axons which link the

neurons. They are surrounded by an insulating

fat sheath, which helps increase the speed of the

nerve signals, as they pass from neuron to

neuron. Other nervous system cells – Schwann

cells and oligodendrocytes – produce and

maintain the sheath. That is the process which

can be observed in the red areas of the image.

Slime moulds look like trees

or germinating cotton seeds

Zebrafi sh embryo looks like blobfi sh

Skin nerves look like

clumps of sea grass

Enlarged:^10

TIMES

Enlarged:^20

TIMES

Enlarged: 60 TIMES

REBECCA NUTBROWN/NIKON SMALL WORLD & SHUTTERSTOCK

DR. OSCAR RUIZ/NIKON SMALL WORLD & POLFOTO & GETTY IMAGES

JOSE ALMODOVAR/NIKON SMALL WORLD & E. RESCHKE/GETTY IMAGES & SHUTTERSTOCK

NATURE MICROSCOPY