Developmental changes in hepatic metallothionein, zinc, and copper levels in genetically altered mice.

Using mice that either overexpress metallothionein 1 (MT-1*) or do not express metallothionein 1 and 2 (MT-null) and a control strain (C57BL/6), the essential metal storage function of hepatic metallothionein and its subcellular localization were investigated during development. Hepatic metallothionein, zinc, and copper levels were measured in all groups from gestational day 20 to 60 days of age. Hepatic metallothionein levels were maximal during the perinatal period in both MT-1* and C57BL/6 mice with levels approximately three times higher in MT-1* mice. MT-null mice had no detectable hepatic metallothionein throughout development. Hepatic zinc levels were highest in the neonatal period of MT-1* and C57BL/6 mice and declined to adult levels by 30 days of age, while hepatic zinc levels in MT-null mice did not vary markedly throughout development. Hepatic copper profiles were very similar in MT-1* and MT-null mice as compared with the C57BL/6 mice. Correlation analysis showed a strong positive correlation between hepatic metallothionein and zinc levels in MT-1* mice, moderate correlation between hepatic metallothionein and metals in C57BL/6 mice, but only a very weak correlation between hepatic metallothionein and copper levels in MT-1* mice. Immunohistochemical localization showed specific nuclear staining in both MT-1* and C57BL/6 mice during the neonatal period with a gradual shift to the cytoplasm. The results show that hepatic metallothionein is a major determinant of zinc but not copper levels during murine development. Additionally, hepatic metallothionein levels and localization are regulated in a similar manner in MT-1* and C57BL/6 mice. The MT-null mice maintain a basel level of zinc sufficient for development, which was found to be 15.9 micrograms/g. This value was similar to the levels of hepatic zinc that was not bound to metallothionein in MT-1* and C57BL/6 mice during development.     

Synthesis of protoporphyrin IX induced by 5-aminolevulinic acid in yeast cells in the presence of 2,2;-dipyridyl

5-Aminolevulinic acid (ALA), a precursor of porphyrin synthesis, increased the production of various porphyrin compounds in Candida guilliermondii cells. Metalloporphyrins and protoporphyrin IX (PPIX) were predominantly accumulated, respectively, at ALA concentrations of 0.2-0.4 mM and at those higher than 1.5 mM. 2,2;-Dipyridyl which complexed with bivalent metals significantly increased the content of endogenous PPIX even at ALA concentrations lower than 0.5 mM. Under these conditions, the yeast sensitivity to photodynamic effect of visible light (400-600 nm) dramatically increased due to photosensitization by endogenous PPIX.     

Change in acetylcholinesterase during early phase of experimental spinal cord trauma in primates

Specific activity of acetylcholinesterase has been shown to be decreased following experimental spinal cord trauma (200 gcm) in primates. The decrease in activity was evident at 8, 24, 48 hr and 1 week after injury to the traumatized segments of spinal cord.     

ISOLATION AND CHARACTERIZATION OF GLYCOSAMINOGLYCANS IN BRAIN OF DIFFERENT SPECIES

Abstract— The uronic acid-containing glycosaminoglycans present in the brains of rat, monkey, chicken, sheep and rabbit were isolated into various fractions by combining the cetyl pyridinium procedure and DEAE-Sephadex column chromatography. The analyses of the fractions show that hyaluronic acid, chondroitin-4-sulphate, chondroitin-6-sulphate, heparan sulphate and a testicular hyaluronidase-resistant galactosamine-containing GAG are present in the brain of all the species studied. Hyaluronic acid is the major GAG (33–41 per cent). Chondroitin-4-sulphate (19–35 per cent), and heparan sulphate (11–19 per cent), are the next prominent GAGs, in all the species except chicken. The results indicate the similarity in the pattern of GAGs in the brain of all the species.     

Fine structure and cytochemical evidence for the presence of polysaccharide surface coat of Dirofilaria immitis microfilariae

Cherian P. V., Stromberg B. E., Weiner D. J. and Soulsby E. J. L. 1980. Fine structure and cytochemical evidence for the presence of polysaccharide surface coat of Dirofilaria immitis microfilariae. International Journal for Parasitology10: 227–233. Cytochemical staining techniques were employed at the fine structural level using ruthenium red, ruthenium violet and Alcian blue-lanthanum nitrate to demonstrate the polysaccharide rich surface coat of Dirofilaria immitis microfilariae. The coat matrix present at the external surface of the cuticle of microfilariae stained densely with each of the polycationic dyes. The reaction products were restricted to the outer surface of the cuticle suggesting that the polycationic dyes did not penetrate the cuticle. The junctions of the cuticular annulations lacked surface coat matrix and reaction products which might be indicative of the absence of carbohydrate residues or the masking of reactive sugar molecules in these areas. The speciflcity of the reaction was indicated by the absence of reaction products in untreated organisms. These carbohydrate moieties probably represent glycoproteins as structural constituents of the parasite surface. Ultrastructural analysis of the surface of microfilariae is of signiflcance in elucidating both the molecular dynamics of the parasite surface and its immunological function in the host.