Bound Gallery

T lymphocytes and cancer cell, SEM C001/1679

T lymphocytes and cancer cell. Coloured scanning electron micrograph (SEM) of T lymphocyte cells (green) attached to a cancer cell. T lymphocytes are a type of white blood cell that recognise a specific site (antigen) on the surface of cancer cells or pathogens and bind to it. Some T lymphocytes then signal for other immune system cells to eliminate the cell. The genetic changes that cause a cell to become cancerous lead to the presentation of tumour antigens on the cell's surface. Magnification: x2300 when printed at 10 centimetres wide

© STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY

Zinc fingers bound to a DNA strand

Zinc fingers bound to a DNA strand, molecular model. The double helix of DNA (deoxyribonucleic acid, red and yellow) is seen here with two Zif268 proteins (blue and green). A zinc finger is a type of DNA-binding domain. It is found in a wide range of DNA-binding regulatory proteins. Zinc fingers are so named for their resemblance to fingers projecting from the protein. They afford the protein a purchase on the DNA by projecting a precise arrangement of side chains into the helical DNA molecule. Each Zif268 protein has three fingers

© LAGUNA DESIGN/SCIENCE PHOTO LIBRARY

Spores of field horsetail

False colour scanning electron micrograph of spores of the field horsetail, Equisetum arvense. The horsetail is the only living type of a primitive family of plants, the Sphenopsids, that were predominant at the formation of the coal measures. The vegetative stems are produced from underground rhizomes & the leaves are reduced to toothed sheaths at the leaf joints. Fertile shoots bear conelike sporangia, carrying the spores, which in this species appear in Spring. The picture shows moist spores bound tightly by their elators, or bands of thickened cells. As the spores dry out, the elators unfurl, tossing the spores out of the sporangium. Mag: X 114 at 35mm. Original is BW print b450/025

© DR JEREMY BURGESS/SCIENCEPHOTO LIBRARY