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The Duffy blood group antigen is an essential receptor for Plasmodium vivaxentry into erythrocytes in a process mediated by the parasite ligand, the Duffy binding protein (DBP). Recently, individuals living in a malaria endemic region of Papua New Guinea were identified as heterozygous for a new allele conferring Duffy negativity, which results in 50% less Duffy antigen on their erythrocytes. We demonstrate that DBP adherence to erythrocytes is significantly reduced for erythrocytes from heterozygous individuals who carry one Duffy antigen negativity allele. These data provide evidence that emergence of this new allelic form of Duffy negativity is correlated with resistance against vivax malaria.

Respiratory rates involving the alternative oxidase (AO) were studied in mitochondria from Tapesia acuformis. There was no evidence for regulation by pyruvate, in contrast with plant AO. The site of interaction of pyruvate with the plant AO is a conserved cysteine. The primary sequence was obtained for AO from Magnaporthe griseaand compared with four published sequences for fungal AO. In all cases this cysteine was absent. Sequence data were obtained for the C‐terminal domain of a further five fungal AOs. In this region the fungal sequences were all consistent with a four‐helix, di‐iron binding structure as in the ferritin‐fold family. A molecular model of this domain was deduced from the structure of Δ‐9 desaturase. This is in general agreement with that developed for plant AOs, despite very low sequence identity between the two kingdoms. Further modelling indicated an appropriate active site for binding of ubiquinol, required in the AO redox reaction.

The hypothesis presented is that the different classes of c-type cytochrome originated as proteins located in the bacterial periplasmic space, or on the periplasmic side of the cytoplasmic membrane. In these locations, covalent bonds between haem and protein prevented the haem from being lost to the surrounding medium. Subsequent evolution has led to internal location of c-type cytochromes in eucaryotes and cyanobacteria. The covalent links have been retained because of their structural role; a b-type cytochrome could be created with similar molecular properties, but its formation would require a large evolutionary jump. If this hypothesis is correct, it should be useful in unravelling electron transport chains with unconventional donors or acceptors. Apparent exceptions deserve further investigation.

A new UV-filter compound, 4-(2-amino-3-hydroxyphenyl)-4-oxobutanoic acid O-glucoside, has been identified in human lenses. The structure suggests that it is derived biosynthetically from tryptophan. Quantification studies on the new compound show that it is the second-most abundant UV-filter compound in the lens with an absorption and fluorescence spectrum similar to that of 3-hydroxykynurenine glucoside.

The α- and β-anomers of d-cellobiose were resolved by 1H NMR spectroscopy. Addition of cellobiose dehydrogenase purified from the white-rot P. chrysosporiumled to selective conversion of β- d-cellobiose. The product was identical to cellobionolactone as synthesized from Ca-cellobionate. Overnight incubation of the product led to an altered NMR spectrum, which was also obtained by incubation of cellobionolactone. The new spectrum matched that for Ca-cellobionate. The instability of cellobionolactone explains the detection of cellobionic acid as product in earlier studies.