March Gallery

Culture of Aspergillus nidulans fungus

Aspergillus nidulans. Laboratory petri-dish culture of the fungus Aspergillus nidulans, cause of aspergillosis and mycetoma. Here the fungus is growing on agar in concentric circles from the centre outwards. The dark growth at the edges is the mycelium which forms the body of the fungus. The brown regions at the centre are spores, the reproductive bodies. A.nidulans produces the toxin sterigmatocysin which can cause food contamination. Inhalation of the spores causes the allergic lung reaction aspergillosis in asthmatics and those with lowered resistance. Mycetoma (madura foot) may result when the fungus infects tissue, bone and skin

© GEOFF TOMPKINSON/SCIENCE PHOTO LIBRARY

Engraving of the mirror from Herschels telescope

Telescope mirror. Engraving of the mirror from a telescope built by the German-British astronomer William Herschel (1738-1822). The upper image is a cross-section of the mirror, showing its concave shape. The lower image shows the mirror bound around its edge by an iron hoop with handles. The mirror was completed in 1795 by Herschel and his sister, Caroline. It was 122 cm (48 inches) wide, 8.9 cm (3.5 inches) thick and weighed 960kg. The mirror was concave so that it would act as a lens and focus light. The telescope was 12.3 metres (40 feet) long. The eyepiece was at the top of this to avoid the loss of light caused by a secondary mirror. The telescope was dismantled in 1839

© SCIENCE PHOTO LIBRARY

Coloured X-ray of thigh bone with osteoporosis

Osteoporosis. Coloured X-ray of the head of a femur thigh bone diseased with osteoporosis (brittle bone disease). The ball of the femur (at right) articulates with the hip socket (not seen). In this section through the bone, affected regions appear spongy (blue, pink). Osteoporosis causes a loss in bone density and bones become brittle, thinner, and can easily fracture. When the upper femur is affected fractures of the femur neck (at centre) are common. Osteoporosis is most common in women after the menopause. This is because their ovaries no longer produce oestrogen hormones which help to maintain bone mass. The aging process itself also causes bones to lose density

© PASIEKA/SCIENCE PHOTO LIBRARY