HLA-DRB1 frequencies of non-Austronesian-speaking Gidra in south New Guinea and their genetic affinities with Oceanian populations

DNA typing of HLA-DRB1 genes was conducted for 192 samples from the Gidra who speak one of the non-Austronesian languages and inhabit the southern lowlands of New Guinea. Comparison of the allele frequencies with those of eight other Oceanian populations reveals that the Gidra are genetically closest to the non-Austronesian-speaking Goroka and, next, to the Aboriginal Australian groups, but are remote from the Austronesian-speaking groups in mainland New Guinea and the rest of Melanesia. This finding clearly supports the hypothesis that non-Austronesians and Aboriginal Australians are descendants of the first-stage migrants to Oceania. © 1995 Wiley-Liss, Inc.     

Chemical treatments of the cell packets induced from a Micrococcus luteus mutant and teichuronic acids on the packet surface

Cell packets (MT packets) induced from a tetrads-forming mutant (strain MT) of Micrococcus luteus, both treated with chemical reagents and non-treated, were observed with a scanning electron microscope (SEM). The agglutinability of MT packets with antiserum containing anti-teichuronic acid antibody was examined. The binding of protein A-gold particles to the MT packets, mediated with the antiserum, was also observed with SEM. Gold particles were observed uniformly on the whole packet surface and also on the bridging structure formed by the outermost layer of the cell wall. Mild acid treatment, NaIO4-NaBH4 treatment and mild Smith degradation of the MT packets extremely decreased the agglutinability and binding of protein A-gold particles. The treatments gave a little influence on the surface feature and appreciably destroyed the regular packet structure. It was supposed that teichuronic acids distributed uniformly on the whole packet surface, naturally on the surface of the bridging structure too, and appreciably participated in the maintenance of the regular packet structure.     

Comparison of two kinds of cell packets of Micrococcus luteus by scanning electron microscopy: outermost layer maintaining the packet structure

Two kinds of cell packets of Micrococcus luteus, one having teichuronic acids (TUA) in the cell wall and the other lacking TUA, have been independently reported by two groups of workers. A comparison by scanning electron microscopy of these packets provided a possibly consistent interpretation for the seemingly conflicting opinions whether TUA were involved in packet induction. It was strongly suggested that the packets having TUA in the wall were rigidly maintained by a bridging structure of the outermost layer of the peripheral wall, while the packets lacking TUA showed low contribution of the outermost layer to the bridging structure probably due to the absence of TUA.