Evidence for a malarial parasite interaction site on the major transmembrane protein of the human erythrocyte

Soluble oligosaccharides derived from the surface of human erythrocytes were tested for their ability to competitively inhibit invasion of erythrocytes by Plasmodium falciparum, a malarial parasite. Invasion was most effectively inhibited by erythroglycan, a carbohydrate component of the band 3 transmembrane protein. The lactosamine chains of erythroglycan contributed much of the inhibitory activity. This indication of a primary parasite interaction site on band 3 supports a role for this protein in mediating the radical alterations of the erythrocyte cytoskeleton that accompany invasion.     

Current status of freshwater prawn culture in Vietnam and the development and transfer of seed production technology

ABSTRACT:   In Vietnam, the giant freshwater prawn Macrobrachium rosenbergii is becoming an increasingly important targeted species, as its culture, especially in rice fields, is considered to have the potential to raise income among impoverished farmers. The production of M. rosenbergii based on aquaculture reached over 10 000 tons per year in 2002, having increased from about 2500 tons since the 1990s. Until recently, lack of a stable supply of seed had been an important obstacle to the further expansion and development of M. rosenbergii culture, but cumulative research on larval rearing, especially in the 1990s, has led to the development of new seed production technology based on the 'modified stagnant green water system'. Following its dissemination by the efforts of provincial authorities, hatchery operators, and farmers, the freshwater prawn seed production industry developed rapidly in the Mekong Delta with over 90 hatcheries producing 76.5 million postlarvae in 2003. This is considered to have affected the expansion of rice–prawn farming in the Mekong Delta, leading to increased aquacultural production in the region. This paper reviews the current status of freshwater prawn culture in Vietnam and background history, and presents a socioeconomic evaluation of seed production technology implementation.     

Neutral and acidic milk oligosaccharides of the striped skunk (Mephitidae: Mephitis mephitis)

The biological significance of the tremendous variation in proportions of oligosaccharides and lactose among mammalian milks is poorly understood. We investigated milk oligosaccharides of the striped skunk (Mephitis mephitis) and compared these results to other species of the clade Mustelida. Individual oligosaccharides were identified by proton nuclear magnetic resonance spectroscopy. In the striped skunk, six oligosaccharides were identified: isoglobotriose, 2′‐fucosyllactose, A‐tetrasaccharide, Galili pentasaccharide, 3′‐sialyllactose and monosialyl monogalactosyl lacto‐N‐neohexaose. Four of these have been found in related Mustelida and the other two in more distantly related carnivorans. The neutral and acidic oligosaccharides derive from three core structures: lactose (Gal(β1–4)Glc), lacto‐N‐neotetraose (Gal(β1–4)GlcNAc(β1–3)Gal(β1–4)Glc) and lacto‐N‐neohexaose (Gal(β1–4)GlcNAc(β1–3)[Gal(β1–4)GlcNAc(β1–6)]Gal(β1–4)Glc).     

A cardiac rhabdomyoma in a Guinea pig

A guinea pig (9-week-old) that had been placed in a control group for a pharmacological test was found to have a single nodule on the surface of the right ventricular wall. In a transverse section of the heart after fixation, a whitish mass was found that extended from the subendocardium to the subepicardium of the right ventricular wall. Histopathological examination revealed a spongy network consisting of vacuolated spaces in the myocardium of the right ventricle extending to the myocardium and subepicardium of the right atrium. The vacuolated space was PAS-positive. Immunohistochemical examinations revealed that the lesions contained striated fibers that were positive for anti-desmin and anti-myoglobin. Electron micrographs revealed the lesions resulting in affected striated muscle fibers and accumulations of many glycogen granules. Based on the findings, the lesions were diagnosed as a cardiac rhabdomyoma. This is the first report of application of immunohistochemical examinations to diagnosis of cardiac rhabdomyoma in the guinea pig.     

Clathrin-mediated endocytosis of mammalian erythroid AE1 anion exchanger facilitated by a YXXΦ or a noncanonical YXXXΦ motif in the N-terminal stretch

To explore the roles of the conserved YXXΦ-type motif in the erythroid-specific N-terminal stretch of anion exchanger 1 (AE1), cell surface expression and internalization of various mutants derived from murine erythroid AE1 tagged with an N-terminal enhanced green fluorescent protein and an extracellular FLAG (EGFP-mAE1Flag) were explored in K562 and HEK293 cells. EGFP-mAE1Flag showed rapid internalization, in association with the internalizations of transferrin and the endogenous AE1 chaperone-like protein glycophorin A in K562 cells. Disruption of the conserved Y72VEL sequence markedly reduced the internalization and increased the relative abundance of cell-surface AE1, whereas substitution of the N-terminal region from bovine AE1 that lacks the relevant motif for the corresponding region had less of an effect on internalization. Deletion or substitution mutations of the Y7EDQL sequence in the bovine N-terminal stretch resulted in the decreased internalization of the AE1 proteins. Cell surface biotinylation and deglycosylation studies showed that approximately 30% of the cell-surface EGFP-mAE1Flag and several other mutants was sorted to the plasma membrane without N-glycan maturation in the Golgi apparatus. These findings indicate that the conserved YXXΦ sequence or a noncanonical YXXXΦ sequence in the N-terminal region facilitates the endocytic recycling of erythroid AE1 through a clathrin-mediated pathway.     

Evaluation of the Mehlich 3 Reagent as an Extractant for Cations and Available Phosphorus for Soils in Mozambique

Accurate soil testing procedures contribute to agricultural development of Mozambique. The Mehlich 3 (M-3) procedure has not been evaluated for Mozambican soils despite its wide applicability. Results showed M-3 solution could extract exchangeable calcium (Ca), magnesium (Mg), and potassium (K) as well as 1 M ammonium acetate (NH₄OAc), while M-3 was not appropriate for extraction of exchangeable sodium (Na). M-3 was an alternative procedure to Bray-I for available phosphorus (P) extraction. Although M-3 extracted 1.6 times more P than Bray-I, determination coefficient between the two procedures showed significantly high value. P content in M-3 extracts can determine using inductively coupled plasma spectrophotometers (ICP) to maximize the merits of M-3. In conclusion, M-3 is applicable for determination of exchangeable Ca, Mg, K, and available P, in a single determination using ICP, and should contribute to development of effective and accurate soil diagnosis in Mozambique.