Canarion,ein neues naphthochinon aus Usnea canariensis

The structure of canarione, a new naphthoquinone from the lichens Usnea canariensis and U. hookeri was elucidated by UV, ¹H-NMR, ¹³C-NMR, mass spectrometry, and chemical degradation as 5,8-dihydroxy-2-methyl-4H-naphtho [2,3b]-pyran-4,6,9 (6H, 9H)- trione.     

Small-angle X-ray scattering study of ribosomal proteins S3, S4 S7 and s20.

Ribosomal proteins S3, S4, S7, S20 from Escherichia coli have been studied by small-angle X-ray scattering techniques. The molecular weights found by X-ray scattering agree with other determinations. The large values of the radii of gyration indicate anisometric particles. A more detailed morphological analysis is hindered by low solubility. An interpretation of the experimental results is given in terms of compact objects of simple shape. Yet the possibility is envisaged that these proteins may be less rigid and compact than other proteins.     

Marabou Storks Wash Dung Beetles

Marabou Storks in their natural environment were observed to practise an insightful method of food amelioration.     

Structural features of archaebacterial cell envelopes

Regularly arrayed surface (glyco)proteins—often referred to as S layers—are a common feature of the cell envelopes of almost all archaebacteria. We have selected some examples (Halobacterium, Sulfolobus, Thermoproteus, Pyrobaculum, Staphylothermus), and we describe the structure of their surface layers as revealed primarily by electron crystallography. In spite of a considerable diversity in shapes and dimensions, some common structural features emerge from the comparison. The glycoprotein arrays are composed of oligomeric units which are anchored in the plasma membrane; extended spacer or linker domains maintain the bulk of the more or less porous surface layers at a constant distance above the membrane surface, thus creating a quasi-periplasmic compartment. Functions ascribed to surface layers, such as compartmentalization, shape maintenance and determination, and adhesion are discussed.