Yoichi Tamai

Association of anti-GM2 antibodies in Guillain-Barré syndrome with acute cytomegalovirus infection

We examined serum anti-cytomegalovirus (CMV) and anti-ganglioside antibodies by ELISA in 51 patients with Guillain-Barré syndrome (GBS), and titers were compared with those from 47 normal and 74 disease controls. Three GBS patients with IgM anti-CMV antibodies had high titers of IgM and IgG anti-GM2 antibodies. The other GBS patients without IgM anti-CMV antibodies, and the normal and disease controls except one of 6 non-GBS patients with acute CMV infections had no anti-GM2 antibodies. The titers of anti-GM2 antibodies decreased on absorption with CMV-infected cells. These findings suggest that anti-GM2 antibodies are associated with acute CMV infections in GBS patients.

Proposal for a procedure for complete inactivation of the Creutzfeldt-Jakob disease agent

We have examined complete inactivation conditions on brain homogenates from mice affected with Creutzfeldt-Jakob disease agent, and recommend for routine use a reliable procedure first treating the affected materials with 1 N NaOH for 60 min and then autoclaving at 121 degrees C for 30 min.

Phylogenetic relation of lungfish indicated by the amino acid sequence of myelin DM20

The cDNA of lungfish Protopterus annectens myelin DM20 was cloned, and the complete amino acid sequence of Protopterusannectens DM20 was deduced. When five possible phylogenetic trees were tested for the DM20 sequences, the maximum likelihood method supported tree 1 [((tetrapods, lungfish), coelacanth), zebrafish, shark] or tree 5 [(tetrapods, lungfish), (coelacanth, zebrafish), shark]. Both tree 1 and tree 5 indicate that lungfish is phylogenetically the closest to tetrapods among the living fishes.

Circadian Behavioural Rhythm in Caenorhabditis elegans

We are very grateful to M. Souma for his technical assistance, and Ian G. Gleadall for comments on the manuscript. This work was partly supported by the Project Fund of Graduate School of Medicine, Kitasato University.

Caenorhabditis elegans opens up new insights into circadian clock mechanisms

The roundworm, Caenorhabditis elegans, is known to carry homologues of clock genes such as per (= period) and tim (= timeless), which constitute the core of the circadian clock in Drosophila and mammals: lin‐42 and tim‐1. Analyses using WormBase (C. elegans gene database) have identified with relatively high identity analogous of the clock genes recognized in Drosophila and mammals, with the notable exception of cry (= cryptochrome), which is lacking in C. elegans. All of these C. elegans cognates of the clock genes appear to belong to members of the PAS‐superfamily and to participate in development or responsiveness to the environment but apparently are not involved in the C. elegans circadian clock. Nevertheless, C. elegans exhibits convincing circadian rhythms in locomotor behavior in the adult stage and in resistance to hyperosmotic stress in starved larvae (L1) after hatching, indicating that it has a circadian clock with a core design entirely different from that of Drosophila and mammals. Here two possibilities are considered. First, the core of the C. elegans circadian clock includes transcriptional/translational feedback loops between genes and their protein products that are entirely different from those of Drosophila and mammals. Second, a more basic principle such as homeostasis governs the circadian cellular physiology, and was established primarily to minimize the accumulation of DNA damage in response to an environment cycling at 24 h intervals.

Alterations in the composition of brain lipids in patients with Creutzfeldt-Jakob disease ☆

Abstract Brain lipids were isolated from 3 patients with Creutzfeldt-Jakob (C-J) disease and their chemical constituents were investigated. The total lipid content increased slightly in diseased gray matter. Ganglioside was reduced to less than 20 and 50% of that of control values in gray and white matter of the Creutzfeldt-Jakob brains, respectively, on both a wet and dry weight basis. Abnormal thin-layer chromatography patterns were observed in the gangliosides from the diseased brains. The C20-sphingosine in the gangliosides from the Creutzfeldt-Jakob brains was markedly reduced. The ratio of C20 to C18-sphingosine was 0.03 to 0.23 in the diseased gray matter. An alteration in the fatty acid composition of ganglioside was observed in 1 case of C-J disease. The total cholesterol content increased both in gray and white matter of the Creutzfeldt-Jakob brain, and one-third of the total cholesterol was in the esterified form in gray matter. Major fatty acids of cholesterol ester were palmitic and oleic acids. The total phospholipids were severely decreased in the diseased brains, but the relative proportions of the individual phospholipids were constant. Polyunsaturated fatty acids in phosphatidyl ethanolamine from the diseased gray matter decreased with a moderate increase in oleic acid. Galactolipid levels and types were essentially unchanged. From the above described abnormalities of brain lipids, the pathogenesis of this disease is discussed.

Suppression of CYP3A2 mRNA expression in the warfarin-resistant roof rat, Rattus rattus: possible involvement of cytochrome P450 in the warfarin resistance mechanism

1. The continual use of warfarin as a rodenticide has caused the development of populations of warfarin-resistant roof rat. To study the biochemical mechanism of warfarin resistance, the mRNA expression levels of the major P450 forms in the warfarin-resistant and -susceptible roof rat liver following exposure to warfarin were quantified by competitive RT-PCR. 2. The constitutive levels of CYP2C11 and CYP3A2 mRNAs in the warfarin-resistant and -susceptible roof rat were extremely low compared with those in the SD rat. In response to warfarin administration, the CYP3A2 mRNA level in the warfarin-susceptible rat increased to about 3-fold of that before the treatment, whereas in the warfarin-resistant roof rat, CYP3A2 mRNA remained at a low level. 3. The present results suggest the possibility that reduced synthesis of CYP3A2 mRNA is involved in the warfarin-resistant mechanism in the roof rat.

Characteristic Constituents of Glycolipids from Frog Brain and Sciatic Nerve

Abstract: Cerebroside, sulfatide, monoglycosyl glyceride, and ester cerebroside were isolated from frog brain and sciatic nerve, and their distribution and chemical constituents were determined. The long‐chain base compositions of cerebroside, sulfatide, and ester cerebroside were unique in the presence of branched‐base components (5–15% of the total bases) and in the abundance of saturated dihydroxy base components (15–45% of the total). The amount of branched long‐chain bases was greater in sciatic nerve than in brain. The hexose composition of the glycolipids consisted entirely of galactose except for brain cerebroside, in which a small amount of glucose was detected. Monogalactosyl glyceride consisted of the diacyl and alkylacyl forms, in a molar ratio of 81:19 for brain and 62:38 for sciatic nerve. The fatty acid com position of glycosphingolipids was characterized by the predominance of hydroxy and nonhydroxy 24:1 acids, and the concentration of 24:0 was extremely low. The proportion of unsaturated fatty acids accounted for 80% of the total. Major fatty acids of monogalactosyl glyceride were palmitic, oleic, stearic, and palmitoleic acids; the highest concentration was that of palmitic acid. Ester cerebroside was separated into three subfractions mainly on the basis of the proportion of hydroxy and nonhydroxy components in the amide‐linked fatty acids.

A monoclonal antibody against a glycolipid SEGLx from Spirometra erinaceieuropaei plerocercoid

A mouse monoclonal antibody AK97 (IgM) was established against a new type of glycosphingolipid, SEGLx, isolated from plerocercoids of tapeworm, Spirometra erinaceieuropaei. The chemical structure of SEGLx (Gal beta1-4(Fuc alpha1-3)(Glc beta1-3Gal beta1-ceramide) had been previously characterized. The specificity of AK97 was determined by thin-layer chromatography-immunostaining and enzyme-linked immunosorbent assay. AK97 was found to be directed to SEGLx and GalSEGLx (Gal beta1-4(Fuc alpha1-3)Glc beta1-3(Gal beta1-6)Gal beta1-ceramide) and also showed cross-reactivity with the stage specific embryonic antigen-1 (SSEA-1), the epitope being defined to be the non-reducing terminal trisaccharide sequence. On immunohistochemical examination, AK97 predominantly stained the tegument, the external surfaces of worms which have a brush border-like organization. Based on the immunohistochemical findings for the staining liability as to organic solvents and the results of Western blot analysis of the plerocercoid glycoproteins, it was proved that the antigens in the tapeworm were glycolipids. Considering that the tapeworm is in direct contact with its hosts tissue through the tegument, the membrane surface of which is exposed to the external environment, it is suspected that SEGLx and GalSEGLx on the tegument play functionally important roles in the host parasite interaction.

Gene Structure and Amino Acid Sequence of Latimeria chalumnae (Coelacanth) Myelin DM20: Phylogenetic Relation of the Fish

The structure of Latimeria chalumnae (coelacanth) proteolipid protein/DM20 gene excluding exon 1 was determined, and the amino acid sequence of Latimeria DM20 corresponding to exons 2–7 was deduced. The nucleotide sequence of exon 3 suggests that only DM20 isoform is expressed in Latimeria. The structure of proteolipid protein/DM20 gene is well preserved among human, dog, mouse, and Latimeria. Southern blot analysis indicates that Latimeria DM20 gene is a single-copy gene. When the amino acid sequences of DM20 were compared among various species, Latimeria was more similar to tetrapods than other fishes including lungfish, confirming the previous finding by immunoreactivity (Waehneldt and Malotka 1989 J. Neurochem. 52:1941–1943). However, when phylogenetic trees were constructed from the DM20 sequences, lungfish was clearly the closest to tetrapods. Latimeria was situated outside of lungfish by the maximum likelihood method. The apparent similarity of Latimeria DM20 to tetrapod proteolipid protein/DM20 is explained by the slow amino acid substitution rate of Latimeria DM20.