缅甸紫金牛属新记录

报道了缅甸克钦邦分布的报春花科(Primulaceae)紫金牛属(Ardisia Swtarz)的3 新记录种:伞形紫金牛(Ardisia corymbifera Mez)、珍珠伞(Ardisia maculosa Mez)和Ardisia interjacens C. M. Hu & J. E. Vidal。     

Xerxes, a new name to replace Alcantara (Asteraceae: Vernoniae)

Xerxes is proposed as a new name to replace Alcantara Glaziou ex G. M Barroso (Asteraceae) (1969), not Alcantarea (Morren ex Mez) Harms (Bromeliaceae) (1929). The genus is monotypic, represented by Xerxes ekmanianum , comb. nov.     

Reduction of Tetrardisia to Ardisia

Larsen, K. & Hu, C. M. 1995. Reduction of Tetrardisia to Ardisia . - Nord. J. Bot. 15: 161–162. Copenhagen. ISSN 0107–055X.
The genus Tetrardisia Mez is reduced to Ardisia Sw. subgenus Tetrardisia subgen. nov. including four species. A key to the species is provided.     

Binding of synthetic peptides by a human monoclonal IgM with an unusual combining site structure

Using X-ray crystallography, a human monoclonal IgM cryoglobulin (Mez) was found to have an unusual combining site topography. Analysis of the unliganded Fv at 2.6 A resolution revealed that the HCDR3 had partitioned the active site into two compartments [Ramsland PA et al. 2000. Mol. Immunol. 37: 295-310]. The two cavities had dimensions and chemical properties that were compatible with the binding of peptides. In this study, libraries of peptides were prepared using solid-phase synthesis. Binding of the intact Mez IgM to these peptides was tested by enzyme-linked immunoassays. Screening of 400 dipeptides revealed that binding was markedly skewed toward amino acids with aromatic side-chains (Phe and Trp), especially when located in the second position. Preferential recognition of aromatic side-chains by Mez IgM was confirmed with larger peptides of three to five residues, but C-terminal positioning was not favored in these peptides. Mez IgM also showed binding propensities for acidic residues (Asp and Glu) as well as several other side-chains with different chemical properties, including His, Pro, Asn and Gln. Mez IgM recognized sets of overlapping octapeptides representing the sequences of the constant domains of human IgG1 heavy chains. These peptides represented similar stretches of polypeptide on the three-dimensional structures of all three constant domains (CH1, CH2 and CH3). Thus, Mez IgM may recognize structurally homologous regions of immunoglobulin domains, which were conserved during the evolution of the immune system.     

Docking of combinatorial peptide libraries into a broadly cross-reactive human IgM

A monoclonal IgM cryoglobulin with diverse binding behavior was isolated from a patient (Mez) with Waldenstr?m's macroglobulinemia. It gave very high titers in the binding of combinatorially synthesized libraries of peptides ranging in size from two to eight residues. The crystal structure of Mez Fv revealed that the binding site was divided into two cavities of unequal volumes with dimensions and chemical properties that were compatible with the binding of peptides. Access to this unique combination of structural information and peptide binding data led us to carry out Mez-peptide docking simulations to gain insight into the Mez binding propensities. In the present article, the results for docking of five peptide libraries are combined with discussions of the methods and approximations involved in the docking process. We analyze the origins of peptide binding affinity for Mez IgM in terms of its cross-reactivity and its structural preferences.     

Chemosystematic implications of flavonoids in Aniba riparia

The trunk wood of Aniba riparia (Nees) Mez (Lauraceae) contains flavokawin-B, (2S)-pinostrombin, (2S)-5, 7-di-O-methylpinocembrin, (2R, 3R)-5, 7-di-O-methylpinobanksin, izalpinin and 3,5, 7-tri-O-methylgalangin. Structural comparison of these flavonoids with the pyrones and neolignans, which characterized all previously examined Aniba spp., leads to a chemical classification of the genus.     

Disruption of Imprinting by Mutator Transposon Insertions in the 5′ Proximal Regions of the Zea mays Mez1 Locus

Imprinting is a form of epigenetic gene regulation in which alleles are differentially regulated according to the parent of origin. The Mez1 gene in maize is imprinted such that the maternal allele is expressed in the endosperm while the paternal allele is not expressed. Three novel Mez1 alleles containing Mutator transposon insertions within the promoter were identified. These mez1-mu alleles do not affect vegetative expression levels or result in morphological phenotypes. However, these alleles can disrupt imprinted expression of Mez1. Maternal inheritance of the mez-m1 or mez1-m4 alleles results in activation of the normally silenced paternal allele of Mez1. Paternal inheritance of the mez1-m2 or mez1-m4 alleles can also result in a loss of silencing of the paternal Mez1 allele. The paternal disruption of imprinting by transposon insertions may reflect a requirement for sequence elements involved in targeting silencing of the paternal allele. The maternal disruption of imprinting by transposon insertions within the Mez1 promoter suggests that maternally produced MEZ1 protein may be involved in silencing of the paternal Mez1 allele. The endosperms with impaired imprinting did not exhibit phenotypic consequences associated with bi-allelic Mez1 expression.