Inhibition of benzoyl peroxide/Cu2+-dependent lipid peroxidation by manganese

1. Formation of peroxides by benxoyl peroxide (BPO) and CuCl2 was examined in the human red blood cell ghost. 2. Amounts of peroxides formed increased with the amount of the ghost solution added. 3. Of all the cations tested only manganese ion inhibited the formation of peroxides in BPO-CuCl2 reaction system. 4. The formation of peroxides was inhibited approx. 50% with 0.4 microM manganese. 5. The inhibitory manner of manganese was non-competitive against copper.     

Changes in the amino acid sequence of hemagglutinin during sequential adaptation of human influenza virus A to replication in mice

The primary structure of hemagglutinin (HA) gene of Influenza virus A/USSR/90/77 (H1N1) variants after 3 and 11 passages has been determined. In the HA1 coding region of mice-adapted virus (11 passages) there are two amino acid substitutions: Thr 89----Ala and Asn 127----Asp. At the first stage of adaptation (3-rd passage) only a single mutation was detected: Asn 127----Asp. The adaptation is accompanied by the loss of specific carbohydrate attachment sites adjacent to the receptor-binding site located at HA1 subunit with a concomitant variation in antigenicity.     

Non-marine Teredolites from the Middle Eocene of southern England

Middle Eocene, non-marine sediments from southern England contain examples of Teredolites borings in two contrasting palaeoenvironmental settings, viz.: (A) as in situ borings in an allochthonous lignite in an abandoned river channel and (B) as bored logs in cross-bedded fluvial sandstones of probable point-bar origin. The lignite is 0.30 m thick, of which the upper 0.20 m is intensely bored. Rounded pebbles of ?charcoal at its base also show small borings. A log in a fluvial sandstone shows densely-packed. radial club-shaped borings. now filled with sandstone. The wood substrate has subsequently been oxidized away. To our knowledge, this is the first detailed account of Teredolites from an ancient freshwater setting.     

EM chromosome mapping using surface-spread polytene chromosomes

Electron micrographs as well as light micrographs of individual surface-spread polytene (SSP) chromosomes indicate more detailed banding patterns than standard squash preparations do. For EM preparations of SSP chromosomes a simple technique is described, avoiding thin-sectioning of chromosomes.     

A comparison of the actions of trypsin and pepsin on porcine immunoglobulin M and their effects on biological activity

The action of trypsin at 55 degree C and pH 8.3 on pig IgM anti-Salmonella has been compared with the action of pepsin at 37 degree C and pH 4.6. Both processes cause the gradual removal of Fab arms and Cmu2 domains to produce eventually an (Fc)5 fragment. However, during tryptic digestion Fab arms are preferentially removed from the same subunit, whereas peptic digestion causes random removal from any subunit. At intermediate stages of digestion both processes produce partially fragmented molecules which consist of an (Fc)5 portion still attached to limited numbers of Fab arms. Both processes cause a gradual decrease in the ability of molecules to agglutinate Salmonella, but complement fixation by the complexes declines much more rapidly. A stage is reached where molecules having four Fab arms can still agglutinate but there is no complement fixation. However, the remaining arms on the tryptic molecules are distributed in pairs on the same subunit, whereas those on the peptic molecules are distributed randomly. Hence the number of remaining Fab arms, rather than their distribution, appears to be the critical factor which influences biological activity. A possible explanation for this is discussed.