Pollination by fungus gnats in four species of the genus Mitella (Saxifragaceae)

The first example of pollination by fungus gnats in the eudicots is reported. The genus Mitella (Saxifragales) is characteristically produces minute, inconspicuous, mostly dull-coloured flowers with linear, sometimes pinnately branched, petals. To understand the function of these characteristic flowers, we studied the pollination biology of four Mitella species with different floral traits and different sexual expression: dioecious M. acerina , gynodioecious M. furusei var. subramosa , and hermaphroditic M. stylosa var. makinoi and M. integripetala. Flower-bagging experiments showed that wind pollination did not occur in the dioecious and gynodioecious species. Two years of observations of flower visitors at six study sites in Japan revealed that the principal pollinators of all four Mitella were specific species of fungus gnats (Mycetophilidae), which landed on the flowers with their long spiny legs settling on the petals. Characteristically, numerous pollen grains were attached to the fungus gnats in specific locations on the body. Although, on average, 1.3–2.6 fungus gnats visited each inflorescence per day, the fruit set of both bisexual and female flowers exceeded 63%. These results suggest that fungus gnats are highly efficient pollinators of Mitella spp., and that Mitella flowers are morphologically adapted to pollination by fungus gnats.  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 144 , 449–460.     

Synthesis of ABO histo-blood group type I and II antigens

The ABO histo-blood group system is one of the most clinically important antigen families. As part of our overall goal to prepare the entire set of the A, B and H type I-VI antigens for a range of biochemical investigations, we report herein the synthesis of the type I and II antigens with a 7-octen-1-yl aglycone. This linker was chosen to facilitate not only the future conjugation of the antigens to a protein or solid support but also the synthesis of the H type I and II octyl glycosides for enzyme kinetic studies.     

The age-sex structure of the slave population in Harris County, Texas: 1850 and 1860

The effect of the slave system on demography can be revealed by examining the age-sex structure of slave populations. The age-sex structure of slaves in Harris County, Texas is investigated using the 1850 and 1860 slave schedules. Median ages for black and mulatto slaves suggest that the population was young. Population pyramids exhibit a narrow base and top with a broad middle. The high proportion of slaves between 10 and 30 years of age and the increase in population size between 1850 and 1860 were mainly related to the importation of slaves and only partly due to natural increase. The data also show that black slaves were older on small plantations while mulattoes were older on larger farms. It is suggested that differential treatment in terms of purchase practices, assignment of tasks, food allocation, and/or differential susceptibility to infectious diseases may account for this pattern.     

A linkage group on pig chromosome 4 comprising the loci for blood group L, GBA, ATP1B1 and three microsatellites

Restriction fragment length polymorphisms (RFLPs) were described for the porcine loci for β-glucosidase (GBA) and the β-polypeptide 1 of the Na⁺, K⁺-transporting ATPase (ATP1B1). Linkage analyses using a three-generation pedigree provided evidence for the assignment of ATP1B1, GBA and two microsatellite loci (S0001 and S0067) to a previously described linkage group comprising the loci for blood group L (EAL) and an anonymous microsatellite (S0097). The linear order of the six markers was determined with confidence by multipoint analyses and the length of the linkage group was estimated at 88 CM. This linkage group was assigned to pig chromosome 4 on the basis of a previous physical localization of the ATP1B1 gene. In situ hybridization data for S0001 presented in this study were consistent with a localization on chromosome 4 and suggested a regional localization to 4pl2-pl3. The present study reveals conflicting data concerning the genetic localization of the K88 loci controlling the expression of the receptors for the E. coli pilus antigens. One group has reported data suggesting a loose linkage between K88 and EAL, now mapped to chromosome 4, whereas two other groups have found linkage between K88 and the transferrin locus (TF), mapped to chromosome 13 by in situ hybridization.     

A Group I Self-Splicing Intron in the Flagellin Gene of the Thermophilic Bacterium Geobacillus stearothermophilus

A group I intron that can be spliced in vivo and in vitro was identified in the flagellin gene of the thermophilic bacterium Geobacillus stearothermophilus. We also found one or two intervening sequences (IVS) of flagellin genes in five additional bacterial species. Furthermore, we report the presence of these sequences in two sites of a highly conserved region in the flagellin gene.     

Characterization of B and H blood-group active glycosphingolipids from human B erythrocyte membranes

Two blood group B active glycosphingolipids (B-I and B-II) previously isolated and highly purified from human B erythrocytes [21] were analysed first by degradation with α-D-galactosidase from coffee beans, α-L-fucosidase from bovine kidney and with 0,1 N trichloracetic acid; the native B-glycolipids as well as their degradation products were then investigated by methylation analysis with combined gas chromatography-mass spectrometry, by thin layer chromatography, twodimensional immunodiffusion and by the hemagglutination inhibition technique. Together with the results obtained by mass spectrometry of permethylated glycolipids [26] the following structures were elucidated: α-D-galactopyranosyl-(1 → 3)-[α-L-fucopyranosyl-(1 → 2)]-D-galactopyranosyl-(1 → 4)-N-acetyl-D-glucosaminosyl-(1 → 3)-D-galactopyranosyl-(1 → 4)-D-glucopyranosyl-(1 → 1)-ceramide for the B-I glycosphingolipid and α-D-galactopyranosyl-(1 → 3)-[α-L-fucopyranosyl-(1 → 2)]-D-galactopyranosyl-(1 → 4)-N-acetyl-D-glucosaminosyl-(1 → 3)-D-galactopyranosyl-(1 → 4)-N-acetyl-D-glucosaminosyl-(1 → 3)-D-galactopyranosyl-(1 → 4)-D-glucopyranosyl-(1 → 1)-ceramide for the B-II glycosphingolipid. A H active glycolipid fraction from B erythrocytes further purified by thin layer chromatography was also investigated by methylation analysis. The pattern of its partially methylated alditol acetates was essentially the same as that of the α-galactosidase treated and permethylated B-I glycolipid. It also exhibited strongly precipitating and hemagglutination inhibiting H properties as well as the two α-galactosidase treated B-I and B-II glycosphingolipids. Based upon these data the following tentative structure was proposed: α-L-fucopyranosyl-(1 → 2)-D-galactopyranosyl-(1 → 4)-N-acetyl-D-glucosaminosyl-(1 → 3)-D-galactopyranosyl-(1 → 4)-D-glucopyranosyl-(1 → 1)-ceramide. Gas chromatographic analysis revealed sphingosine and lignoceric, nervonic and behenic acids to be the main components of the ceramide residues of the three glycosphingolipids. From the data presented the H active substance very probably can be regarded as the immediate precursor of the B-I glycosphingolipid from human B erythrocyte membranes.     

Prolific production of sclerotia in soil by Rhizoctonia solani anastomosis group (AG) 11 pathogenic on lupin

Rhizoctonia solani anastomosis group (AG) 11 causes serious damping‐off and hypocotyl rot of narrow‐leafed lupins (Lupinus angustifolius) in the northern grain‐belt of Western Australia. R. solani AG‐11 produced abundant sclerotia in sand overlaid on potato dextrose agar. Sclerotia were produced in larger numbers in natural Lancelin sand than in Geraldton loamy sand collected from the northern grain‐belt of Western Australia. The majority of the sclerotia produced were in >250 to <500 μam size range. The germination levels of sclerotia in the first two cycles of drying and germination were not significantly different. Sclerotia still retained 50% germination after four such cycles, indicating that they may have the ability to withstand the climatic cycles of the Mediterranean environment of southwestern Western Australia. The radial growth of the mycelium from sclerotia, however, declined with each drying and germination cycle. Inoculum potential of the pathogen increased with the size of sclerotia resulting in more severe lupin hypocotyl rot with larger sclerotia. The number of sclerotia produced in soil increased with increasing density of lupin seedlings. The results also indicate that R. solani AG‐11 can produce sclerotia on infected plant tissues as well as in soil. This is the first report of the prolific production of sclerotia by AG‐11 and their significant role in infection of lupins in soil in Western Australia.     

Poly-N-Acetyllactosamine Glycans of Cellular Glycoproteins: Predominance of Linear Chains in Mouse Neuroblastoma and Rat Pheochromocytoma Cell Lines

To study the properties of protein-bound oligosaccharides in neuronally differentiating cells, two model systems were used: murine N1E-115 and N-18 neuroblastoma cells inducible by serum starvation and rat PC12 pheochromocytoma cells inducible by nerve growth factor. Glycopeptides were prepared from cells metabolically labeled with [3H]glucosamine and analyzed by gel filtration. The properties of the high-molecular-weight glycopeptides were studied using enzymatic digestion with neuraminidase and endo-beta-galactosidase. In contrast to other cell lines analyzed, the neuroblastoma and pheochromocytoma lines contained predominantly glycopeptides completely cleavable with endo-beta-galactosidase, which indicated that they were linear-type poly-N-acetyllactosamine glycans. The proportion of these linear chains in the high-molecular-weight fraction increased during neuronal differentiation in both cell systems. The linear nature of the glycans was also correlated with positive anti-i and negative anti-I reactivity of the cells in immunofluorescence microscopy. Specific cell surface labeling for poly-N-acetyllactosamine glycans and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed several glycoprotein components, some of which showed changes during neuronal differentiation. The high proportion of linear poly-N-acetyllactosamine chains in these neuronal cell lines and its increase during neuronal differentiation suggests that these glycans may be a characteristic feature of neuronal or neuronally differentiating cells.