Phosphorylated tau protein is integrated into paired helical filaments in Alzheimer's disease

Antisera to paired helical filaments (PHF) were found to contain a significant amount of tau antibodies specific for a phosphorylated form, but only a negligible amount of those specific for a non-phosphorylated form. Also, the phosphorylated tau-specific antibodies, but not the non-phosphorylated tau-specific ones, labeled neurofibrillary tangles isolated in the presence of sodium dodecyl sulfate (SDS) and stained both tangles and senile plaque neuritis in fixed tissue sections in a very similar way to as the whole antiserum did. Taken together, these results strongly suggest that a major antigenic determinant of PHF is phosphorylated tau itself.     

Structures of sugar chains of human kidney gamma-glutamyltranspeptidase

gamma-Glutamyltranspeptidase purified from human kidneys contains 4-5 asparagine-linked sugar chains in each molecule. The sugar chains were released from the polypeptide portion of the enzyme by hydrazinolysis as oligosaccharides and separated by paper electrophoresis into one neutral and two acidic fractions. By sequential exoglycosidase digestion and methylation analysis, the neutral fraction, which comprised 69% of total oligosaccharides, was shown to be a mixture of bisected bi- and triantennary complex-type sugar chains with and without a fucose on the proximal N-acetylglucosamine residue and with Gal beta 1----4GlcNAc and/or Gal beta 1----4(Fuc alpha 1----3)GlcNAc groups in their outer chain moieties. The acidic oligosaccharide fractions were mixtures of mono- and disialyl derivatives of bisected triantennary complex-type oligosaccharides with Gal beta 1----4GlcNAc and/or Gal beta 1----4(Fuc alpha 1----3)GlcNAc group in their outer chain moieties. Some of the outer chains of the acidic oligosaccharides were considered to be sialylated X-antigenic structures.     

Specific interaction between tRNA and its cognate amino acid as detected by circular dichroism and fluorescence spectroscopy

Specific interaction was detected between tRNA and its cognate L-amino acid by circular dichroism (CD) and fluorescence spectroscopy; fluorescence spectral change with saturation was observed when tRNAAsp was titrated only with L-aspartic acid, but not with D-aspartic acid, L- and D-glutamic acids. It was also the case for tRNA2Glu and L-glutamic acid as detected by CD. These results are consistent with the hypothesis that the anticodon, or the complex of four nucleotides (C4N) of the anticodon three bases and the discriminator base in a tRNA (Shimizu, M., J. Mol. Evol. (1982) 18, 297-303) participates in recognition of amino acids.     

Suppressors of temperature-sensitive mutations in a ribosomal protein gene, rpsL (S12), of Escherichia coli K12

Summary Temperature-sensitive (ts) mutations were isolated within a ribosomal protein gene (rpsL) of Escherichia coli K12. Mutations were mapped by complementation using various transducing phages and plasmids carrying the rpsL gene, having either a normal or a defective promoter for the rpsL operon. One of these mutations, ts118, resulted in a mutant S12 protein which behaved differently from the wild-type S12 on CM-cellulose column chromatography. Suppressors of these ts mutations were isolated and characterized; one was found to be a mutation of a nonribosomal protein gene which was closely linked to the RNAase III gene on the E. coli chromosome. This suppressor, which was recessive to its wild-type allele, was cloned into a transducing phage and mapped finely. A series of cold-sensitive mutations, affecting the assembly of ribosomes at 20°C, was isolated within the purL to nadB region of the E. coli chromosome and one group, named rbaA, mapped at the same locus as the suppressor mutation, showing close linkage to the RNAase III gene.     

A spin-label study on human high density lipoprotein

Human plasma high density lipoproteins (HDL) have been labeled with N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)maleimide (NEM-TEMPO). The spin-labeled HDL exhibited an ESR spectrum containing signals of both strongly immobilized and weakly immobilized components by the reaction with a high concentration of NEM-TEMPO, while an ESR spectrum containing only signals of a strongly immobilized component range between 4 degrees C and 37 degrees C, the signal height of the strongly immobilized component exhibited reversible temperature-dependent changes, whereas that of the weakly immobilized component changed irreversibly at temperatures above 25 degrees C. The activation energy of the irreversible change was estimated to be 26 kcal per mol. The strongly immobilized component was derived from NEM-TEMPO which modified apolipoprotein A-I covalently, while the weakly immobilized component was derived from NEM-TEMPO noncovalently bound to HDL. The rate of binding of NEM-TEMPO to either the strongly binding or weakly binding sites and the number of the strongly binding sites in apolipoprotein A-I were estimated to be 125 M-1.day-1 and 1.78, respectively. The binding of NEM-TEMPO to the strongly binding sites was suppressed greatly by pretreatment of HDL with 2,4,6-trinitrobenzene sulfonic acid (TNBS). The slow reaction and suppression with TNBS suggest that NEM-TEMPO binds to some amino acid residue, probably a lysine residue, in apoprotein A-I. The strongly immobilized and weakly immobilized components were reduced almost completely by ascorbate at the same rate, 0.048 min-1 at pH 7.4 and at 4 degrees C.     

Feeding ecology of mandrills (Mandrillus sphinx) in campo animal reserve,Cameroon

A field study on the ecology of mandrills (Mandrillus sphinx) was carried out for 28 months in Cameroon. Fresh food remnants and large quantities of fresh feces were collected by following the groups. Analyses of these products indicated that fruit (including seeds), monocotyledonous plant leaves and insects (especially ants and termites), were frequently eaten. Mandrills mostly ate the plant and animal foods in the lower forest stratum and on the ground. Fallen seeds and monocotyledonous plant leaves were eaten more frequently in the minor fruiting season than in the major fruiting season presumably to compensate for the shortage of fresh fruit during the former. Daily travel distances were shorter during the minor fruiting season than during the major fruiting season, because in the minor fruiting season mandrills forage for small food items, such as the new leaves and piths of monocotyledons and fallen seeds which are sparsely distributed on the ground, while in the major fruiting season they search for widely distributed food such as fruit. The daily pattern of group movement and a food intake experiment suggest that mandrills move and feed continuously throughout the day. Use of fallen seeds and monocotyledonous plant leaves appears to enable mandrills to maintain a terrestrial life in the tropical rain forest. The feeding and ranging characteristics of mandrills are basically similar to those of other baboon species in open land, though their environments differ extremely.     

Ontogenesis of gastrin cells in the pyloric antrum and duodenum of the mouse

Summary Ontogenesis of gastrin cells was studied in the pyloroduodenal mucosa of the mouse using anti-human G17 serum, R-1301, and anti-human G34(1–15) serum, R-2703. R-1301-immunostained cells first appeared in the pyloric mucosa of 14-day-old fetuses. Cells stained with both R-1301 and R-2703 appeared immediately after birth, and gradually increased in number to the adult level. Most R-1301-reactive cells were also reactive to R-2703, whereas some cells that reacted with R-1301 exhibited very weak or no reaction with R-2703. The discrepancy between these two immunoreactivities is discussed.In the duodenum, a considerable number of R-1301-reactive cells were present from the perinatal stage and through out adult development. A few R-2703-reactive cells were seen in the duodenum of young mice but not of the adult.     

HPLC-studies on nonmercapt-mercapt conversion of human serum albumin

Human mercaptalbumin (HMA) and nonmercaptalbumin (HNA) could be separated by high-performance liquid chromatography (HPLC) at neutral pH. Using HPLC, the present authors found the nonmercapt-mercapt conversion (HNA----HMA) during hemodialysis and the mercapt-nonmercapt conversion (HMA----HNA) after hemodialysis in chronic renal failure, indicating HMA as the covalent carrier protein for sulfur-containing amino acids.     

Level of translatable messenger RNA coding for argininosuccinate synthetase in the liver of the patients with quantitative-type citrullinemia

Summary The translation activity of mRNA coding for argininosuccinate synthetase in total RNA extracted from the liver of three patients with quantitative-type citrullinemia was determined using a cell-free translation system. In two patients, the hepatic content of the enzyme was about 20% of the control value, whereas translatable mRNA level for the enzyme was similar to or slightly lower than those of control livers. In the third patient, the enzyme content was about 50% of the control value, and mRNA activity for the enzyme was low normal. These results indicate that at least in the first two patients, the decrease in the enzyme protein is due either to increased degradation of the enzyme or to decreased translation in the patient's liver.