In this report, we describe a new lectin from the fungus Rhizopus stolonifer that agglutinates rabbit red blood cells. Agglutinating activity was detected in the extract of mycelium-forming spores cultured on agar plates but not in the mycelium-forming no spores from liquid medium. This lectin, which we designated R. stolonifer lectin (RSL), was isolated by affinity chromatography with porcine stomach mucin-Sepharose. SDS-polyacrylamide gel electrophoresis and mass spectral analysis showed that RSL is ϳ4.5 kDa, whereas gel filtration indicated a mass of 28 kDa. This indicates that the lectin is a hexamer of noncovalently associated RSL monomers. RSL activity was very stable, since it was insensitive to heat treatment at 70°C for 10 min. Analysis of RSL binding specificity by both microtiter plate and precipitation assays showed that N-glycans with L-fucose linked to the reducing terminal GlcNAc residues are the most potent inhibitors of RSL binding, whereas N-glycans without ␣(1-6)-linked fucose residues are ϳ100-fold weaker inhibitors of binding. Oligosaccharides with ␣(1-2, -3, and -4) linkages showed no inhibition of binding in these assays. In a mirror resonance biosensor assay, high affinity binding was observed between RSL and the glycopeptide of bovine ␥-globulin, which has N-glycans with ␣(1-6)-linked fucose residues. However, RSL showed only a weak interaction with the glycopeptide of quail ovomucoid, which lacks fucose residues. Finally, capillary affinity electrophoresis studies indicated that RSL binds strongly to N-glycans with ␣(1-6)-linked fucose residues. Together, these results show that RSL recognizes the core structure of N-glycans with ␣(1-6)-linked L-fucose residues. This specificity could make RSL a valuable tool for glycobiological studies.

GaN crystalline powders have been synthesized by the reaction of a Ga vapor with ammonia at the reaction temperatures (T r) of 900–1100°C under the atmospheric pressure. The size of the crystalline particles ranges from 0.2 to 2 µm. The structural and the luminescent properties depend strongly on T r. For T r≥1050°C, the powders consist primarily of hexagonal GaN particles, whereas those synthesized at T r≤1000°C contain cubic GaN particles. Photoluminescence (PL) spectra are dominated by band-edge emissions. For the powders synthesized at higher T r, reduction in the PL intensity between 24 and 293 K indicates excellent luminescent quality. Thermal quenching is relatively significant for the powders synthesized at lower T r. This is presumably due to enhanced nonradiative recombination at the surface because of their small particle size.

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GaN crystalline powders have been synthesized by the reaction of a Ga vapor with an ammonia gas at the reaction temperature Tr = 900 - 1100°C in an atmospheric-pressure open-tube reactor. The size of GaN particles ranges from 0.2 to 2νm. It was found that the structural and luminescent properties depend strongly on Tr. The mean size of the GaN particles increased as Tr is raised. The GaN powders exhibited photoluminescence (PL) dominated by the band edge emissions. Thermal quenching is relatively significant for the powders synthesized at lower Tr. This is presumably due to enhanced non-radiative recombination at the surface because of their smaller particle size.

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