The family of metazoan metal-independent {beta}-galactoside-binding lectins: structure, function and molecular evolution

Animal metal-independent ß-galactoside-binding lectinswere initially found in vertebrates, but they have recentlybeen isolated from much lower invertebrates, such as nematodeand sponge, as well. Further, an eosinophilic lysophospholipaseassociated with various inflammatory reactions was very recentlyfound to be a new member of this protein family. It appearsthat ß-galactoside-binding lectins and some non-lectinproteins form a superfamily whose members are widely distributedfrom vertebrates to invertebrates. From the viewpoints of proteinarchitecture, the superfamily members can be subdivided intothree types; i.e. ‘proto type’ (the relatively well-studied14 kDa lectins), ‘chimera type’ (29–35 kDalectins also known as     

Characterization of four monosialo and a novel disialo Asn N-glycosides from the urine of a patient with aspartylglycosaminuria

We previously reported for the first time two Japanese patients with aspartylglycosaminuria (AGU). A novel disialo Asn N-glycoside (AG-5) has been isolated from the urine of one of the patients in addition to four known monosialo Asn N-glycosides (AG-1 to AG-4) by gel filtration and anion exchange chromatography in this study. Final purification of AG-5 was achieved by an electrochemical chromatographic method, high performance liquid chromatography with pulsed amperometric detector (HPLC-PAD). The yield of AG-5 was approximately 1 mg l^–1 urine. The chemical structures of AG-1 to AG-5 were characterized by gas-liquid chromatography, a permethylation study, fast atom bombardment-mass spectrometry (FAB-MS), and nuclear magnetic resonance (NMR). Based on the structural analysis, AG-5 had the following novel structure: NeuAc2 8NeuAc2 3Gal1 4GlCNAc1 Asn.     

Involvement of blood-group-B-active trisaccharides in Ca2+-dependent cell-cell adhesion in the Xenopus blastula

 Despite their wide distribution in various organisms, no physiological roles have been proposed for the human blood-group-ABO (ABH)-active trisaccharides. Here we show that monoclonal antibodies against human blood-group-B-active trisaccharides (B-substance) completely block the Ca²⁺-dependent cell-cell adhesion system of frog (Xenopus laevis) embryonic cells. Synthetic B-substance or B-active glycopeptides also disrupt the Ca²⁺ -dependent cell-cell adhesion. These results suggest that blood-group-B-active substances play a role in cell-cell adhesion. Blood-group-B-active substances were found as glycoproteins and as glycosphingolipids. In order to identify B-active glycoproteins active in cell-cell adhesion, we purified B-active membrane glycoproteins by two-dimensional electrophoresis and found that they are 45- to 58-kDa proteins with pI(s) ranging from 4.0 to 5.3. They are glycosylphosphatidyl inositol (GPI) anchored. Amino acid sequence analysis showed that the purified B-active GPI-anchored proteins are homologues of soluble Xenopus cortical granule lectins (CGL). The results suggest that the B-active membrane glycoproteins are GPI-anchored forms of the lectin and are directly involved in frog Ca ²⁺-dependent cell-cell adhesion. Received: 16 September 1997 / Accepted 19 November 1997     

Electric convulsive therapy (ECT) increases plasma and red blood cell haloperidol neuroleptic activities

In nine schizophrenic patients (five males and four females) on haloperidol treatment, plasma and red blood cell (RBC) haloperidol neuroleptic activities were measured before and after ECT by radioreceptor assay. Five patients randomly selected from these patients also served as controls on another occasion and neuroleptic activities in plasma and RBC were examined before and after the premedication only. All patients given ECT showed a considerable increase in plasma and RBC haloperidol neuroleptic activities after ECT (% increase in plasma neuroleptic activity, 28–409%; mean + SD, 136 ± 155%, P<0.005, Wilcoxon test; % increase in RBC neuroleptic activity, 11–121%; mean + SD, 59 ± 40%, P<0.005). However, no significant increase was observed for either plasma or RBC haloperidol neuroleptic activity, when patients were examined after premedication only. It was suggested that ECT induced a transient redistribution of haloperidol. It remains to be studied whether this phenomenon is causally related to the previous observation that the combination therapy of ECT and neuroleptics is more effective in the treatment of schizophrenia than ECT alone.     

Presence of activator proteins for the enzymic hydrolysis of GM1 and GM2 gangliosides in normal human urine

Normal human urine has been found to contain activator proteins that stimulate the enzymic hydrolysis of GM1 and GM2 gangliosides. These two activators were partially purified by Sephadex G-200 filtration and DEAE-Sephadex A-50 chromatography. The presence of these two activators was assayed by demonstrating the stimulation of the in vitro hydrolysis of GM1 and GM2 gangliosides. As little as 50 ml of urine is sufficient to detect the presence of these two activators. The crude activator preparation from normal urine was also found to stimulate the hydrolysis of galactosylceramide sulfate by arylsulfatase A.     

Role of Nine Repeating Sequences of the Mini-F Genome for Expression of F-Specific Incompatibility Phenotype and Copy Number Control

An autonomously replicating 2,248-base-pair DNA segment of the mini-F plasmid carries nine 19-base-pair repeating sequences. Five of the repeats are arranged in one direction and form the right cluster, whereas the remaining four repeats are arranged in the opposite direction and form the left cluster (Murotsu et al., Gene 15:257-271, 1981). Each cluster, cloned separately into the multicopy plasmid vector pBR322, exhibited a strong F-specific incompatibility phenotype (FIP). These clusters were thought to be responsible for the expression of IncB and IncC phenotypes, causing a switchoff function on mini-F replication. Mini-F DNA fragments containing two, three, or more than four repeats were inserted into pBR322. Cells carrying these recombinant plasmids exhibited, respectively, no, intermediate, and strong FIP intensity. Cloning of five repeats into pSC101, whose copy number is about 6 in contrast to 20 for pBR322, resulted in an FIP of intermediate intensity. Thus, the intensity of FIP reflects the dosage of repeats in a cell. The five repeats in the right cluster were eliminated from the mini-F derivative without impairing its autonomous-replicating ability (Bergquist et al., J. Bacteriol. 147:888-889, 1981; Kline and Palchavdhuri, Plasmid 4:281-289). Such deletion, however, caused a sixfold elevation of the copy number. When the eliminated cluster of repeats was reinserted in the derivative, the copy number was lowered to the original value, viz., 1 to 2. The position and orientation of this insertion was not important in the copy number control. Thus, the repeats are also related to copy number control. A model to account for the role of the repeating sequences in the control of copy number and FIP is discussed.     

Evolution of alliance in primates: A population genetic model

Alliance behaviors in anubis baboons, chimpanzees, Japanese monkeys, and rhesus monkeys are briefly described. Alliance differs from simple altruism or cooperation between 2 individuals in that a third conspecific individual, the common enemy, is adversely affected. Two models of alliance formation are considered, one in which support is given unilaterally and the other in which both parties can profit. It is assumed that the allies are equally related to each other and to the common enemy. Using a quantitative genetic model, conditions are derived for alliance behavior to be selectively advantageous. The models are applied to reciprocal altruism between adult male anubis baboons and manipulation by adult male chimpanzees. It is argued that reciprocally altruistic alliance in baboons as described is difficult to reconcile with theory.     

Genetic regulation of the class conversion of dsDNA-specific antibodies in (NZB × NZW)F1 hybrid

To investigate the possible effects of NZW genes on the class conversion of dsDNA-specific antibodies in NZB X NZW (B/W)F1 hybrids, we measured IgM, IgG1, and IgG2 dsDNA-specific antibodies, using the Crithidia luciliae kinetoplast immunofluorescence test, in NZB, NZW, B/W F1 hybrid, B/W F1 X NZB backcross, and B/W F1 X NZW backcross mice at 4, 7, and 10 months of age. The highest serum levels of IgM dsDNA-specific antibodies were observed in NZB mice at the ages tested; however, the amounts of IgG1 and IgG2 antibodies were scanty. In contrast, a large amount of both IgG1 and IgG2 dsDNA-specific antibodies was produced in B/W F1 hybrids, in which the serum IgM antibodies were lower than those observed in NZB mice. NZW mice were virtually negative for these antibodies. Progeny testing suggested that a combined effect of two unlinked dominant genes of the NZB strain determines the production of dsDNA-specific antibodies and that these genes only act to produce IgM antibodies. These traits are to a great degree modified by the NZW loci in B/W F1 hybrids, and a combined effect of two unlinked dominant genes leads to conversion of the class of the antibodies from IgM to IgG, which, in turn, increases the serum levels of dsDNA-specific antibodies. The F1 hybrid of C57BL/6 and NZW strains produced no dsDNA-specific antibodies, indicating that the relevant NZB predisposing genes are required for the NZW gene action. Linkage studies showed that one of such NZW genes is to some extent linked to the H-2 complex on chromosome 17, but not to Mup-1 (chromosome 4) or a coat color locus (chromosome 2). The appearance of IgG dsDNA-specific antibodies correlated well with the incidence of renal disease in B/W F1 X NZB backcross mice.     

Estimating evolutionary distance from restriction maps of mitochondrial DNA with arbitrary G+C content

Summary We develop a mathematical model for estimating evolutionary distance from restriction enzyme maps, which incorporates non-uniformity of the rate of base substitution into the theory and allows for an arbitrary G+C content at equilibrium. When the G+C content differs significantly from 1/2, the traditional model of base changes can introduce a systematic bias which depends upon the base composition of the restriction site. In addition, the accuracy of estimated evolutionary distance depends heavily upon the choice of restriction enzyme in that the expected number of sites is also affected. Monte Carlo experiments are conducted to check the validity of the present theoretical treatment and from which we draw several cautionary notes on estimation. An application is made to the available data on restriction enzyme maps of human mitochondrial DNA where the G+C content is approximately 1/3.Contribution No. 1372 from the National Institute of Genetics, Mishima, 411 Japan