Identification of novel decenoic acids in heated butter

Novel decenoic acids such as (E)-4-decenoic acid and (E)- and (Z)-5-,6-decenoic acid were detected as minor components in heated butter using GC and GC/MS. The formation mechanism of these novel decenoic acids is discussed on the basis of the result of the reaction of delta-decalactone with active clay in a model experiment.     

Quantitative determination of endogenous sorbitol and fructose in human erythrocytes by atmospheric-pressure chemical ionization LC tandem mass spectrometry

Evaluation of different extraction methods for quantification of endogenous sorbitol and fructose in human red blood cells (RBCs) and matrix effects in ESI and APCI showed that protein-precipitation followed by mixed-mode solid-phase extraction was more effective extraction method and APCI more effective ionization method. Then the LC/APCI-MS/MS method was fully validated and successfully applied to analysis of clinical RBC samples. The concentrations of endogenous sorbitol and fructose were determined using calibration curves employing sorbitiol-13C6 and fructose-13C6 as surrogate analytes. The method has provided excellent intra- and inter-assay precision and accuracy with a linear range of 50.0-10,000 ng/mL (correlation coefficient >0.999) for sorbitol-13C6 and 250-50000 ng/mL (correlation coefficient >0.999) for fructose-13C6 in human RBCs.     

Naturally occurring cytotoxic T lymphocyte precursors with specificity for an Ig idiotype

The humoral response to the p-azobenzenearsonate hapten in the A/J mouse includes the major cross-reactive idiotype associated with anti-p-azobenzenearsonate (CRIA) found in all immunized mice. Limiting dilution cultures of non-immunized spleen cells of A/J mice with irradiated B hybridoma cells bearing the Ig idiotype, CRIA, in the presence of T cell growth factors developed cytotoxic activity against the CRIA-bearing hybridoma; in some wells this activity was completely abrogated by an anti-idiotype mAb specific for CRIA or by a univalent hapten antigen, tyrosine-p-azobenzenearsonate, indicating the existence of cytotoxic T cell precursors (CTL-P) specific for one or more idiotopes of CRIA in normal spleen cells. The CTL clones lysed targets in a H-2D-restricted manner and were cytotoxic for CRIA-bearing hybridoma lines, but not for CRIA-non-bearing, IgG1k-bearing hybridoma lines. These CTL-P were detected at a high frequency (1/4,500 to 1/10,000) in a spleen cell population of non-immunized, relatively aged A/J mice (16 to 30 wk of age), and at a lower frequency in spleen cells of younger A/J mice (8 wk of age). However, they were not detected in normal spleen cells of B10.A (CRIA-non-producer) mice at any age (less than 1/6 x 10(5)). Normal Ighd-congenic C.AL-20 mice (16 wk of age), that are CRIA producers had as a high frequency of the CTL-P as did A/J mice, whereas normal Ighb-congenic C.B-20 mice (CRIA-non-producers) had none. In the spleen cells of the CRIA-producers, cytotoxicity of the CTL-P developed only in cultures with small numbers of seeding cells. They were completely absent in cultures with greater numbers of cells; this may be due to the presence of suppressor cells of lower frequency but greater potency. In lymph node cells or PBL of relatively aged A/J mice, the CTL-P were also detected, but only in cultures containing higher cell numbers, and at low frequency (between 1/5 x 10(5) to 1/2 x 10(6)). In thymocytes of 8-wk-old A/J mice, they were occasionally detected at very low frequency (less than or equal to 1/1 x 10(6)), but were not present in the bone marrow cells at any age. These results demonstrate the high incidence of the generation of CTL-P specific for an autologous Ag, and indicate that CRIA on B cells may induce CTL specific for CRIA. However, the development of CTL-P may be inhibited by co-existent suppressor cells under normal conditions.     

Multiple forms of poly(A) polymerases purified from HeLa cells function in specific mRNA 3''-end formation.

Poly(A) polymerases (PAPs) from HeLa cell cytoplasmic and nuclear fractions were extensively purified by using a combination of fast protein liquid chromatography and standard chromatographic methods. Several forms of the enzyme were identified, two from the nuclear fraction (NE PAPs I and II) and one from the cytoplasmic fraction (S100 PAP). NE PAP I had chromatographic properties similar to those of S100 PAP, and both enzymes displayed higher activities in the presence of Mn2+ than in the presence of Mg2+, whereas NE PAP II was chromatographically distinct and had approximately equal levels of activity in the presence of Mn2+ and Mg2+. Each of the enzymes, when mixed with other nuclear fractions containing cleavage or specificity factors, was able to reconstitute efficient cleavage and polyadenylation of pre-mRNAs containing an AAUAAA sequence element. The PAPs alone, however, showed no preference for precursors containing an intact AAUAAA sequence over a mutated one, providing further evidence that the PAPs have no intrinsic ability to recognize poly(A) addition sites. Two additional properties of the three enzymes suggest that they are related: sedimentation in glycerol density gradients indicated that the native size of each enzyme is approximately 50 to 60 kilodaltons, and antibodies against a rat hepatoma PAP inhibited the ability of each enzyme to function in AAUAAA-dependent polyadenylation.     

Natural cytotoxic activity in a cloned natural killer cell line is mediated by tumor necrosis factor

The interleukin-2-dependent mouse natural killer (NK) cell line NKB61A2 concomitantly exhibits NK and natural cytotoxic (NC) activities. This was determined by the cells' ability to lyse both the NK-sensitive YAC-1 lymphoma and the NC-sensitive WEHI-164 fibrosarcoma cell lines in a 4- and 18-hour 51Cr release assay, respectively. Cell-free supernatant from NKB61A2 cells grown in culture for 48 h had substantial lytic activity against WEHI-164. The mouse mast cell line PT18-A17 and the rat basophilic leukemia cell line RBL-2H3, which both express NC activity, also produced a soluble factor during culture which lysed WEHI-164 cells. This activity was increased in the basophilic/mast cells by crossbridging the surface IgE receptors. Similar results were obtained by triggering the basophilic NC cells with the calcium ionophore ionomycin and the tumor promoter phorbol-12-myristate-13-acetate (PMA). Such triggering of NKB61A2 cells, however, did not significantly increase their NC activity. Interestingly, both ionomycin and PMA had an inhibitory effect on the NK activity of NKB61A2. Recently it has been found that tumor necrosis factor (TNF) is a major mediator of NC activity. To determine if the soluble factor responsible for the NC activity of the NK clone was related to TNF, a rabbit polyclonal antiserum to mouse TNF was tested against the cell-free culture medium of NKB61A2, PT18-A17, RBL-2H3 and murine recombinant TNF (Mu-rTNF). The lytic activity of the culture medium from all these cells and the Mu-rTNF control was abrogated by this antibody. These data suggest that the murine cell line NKB61A2 has both NK and NC activities and that the NC activity is due to a factor immunologically similar to TNF. In addition, the enhancement of NC activity in the NK cell line is apparently under control by a separate pathway, different from that in the basophilic cells.     

DEVELOPMENTAL CHANGES IN GLYCOLYSIS IN RAT CEREBRAL CORTEX

Abstract— The ATP concentration in infant rat cerebral cortex slices which were incubated aerobically with glucose (5 m m ) as substrate was much higher than in those from the adult. The higher ATP concentration in slices from young rat was also obtained when they were incubated aerobically with pyruvate (10 m m ), dl -lactate (20 m m ) and dl -3-nydroxybutyrate (20 m m ) However, when the slices were incubated anaerobically with glucose, the ATP concentration was very low. Thus, the formation of ATP in the slices from the young rat was thought to be mainly due to their oxidative metabolism, as in those from the adult. The amounts of glycolytic key enzymes in rat cerebral cortex (hexokinase. phosphofructokinase and pyruvate kinase) increased with age. Glycolysis was actually shown to be less active in the cerebral slices from young rats than from the adult. In addition it is known that the tricarboxylic acid cycle enzymes in rat cerebrum also increase with age. Consequently, the activity with respect to ATP formation must be lower in the cerebral cortex slices from young rats than from the adult. The fact that ATP was nevertheless higher in the slices from young rats may be explained by a lower rate of degradation. Developmental increases in the amounts of Na⁺-K⁺-ATPase and Mg²⁺ -ATPase in rat cerebral cortex were greater than those of the glycolytic key enzymes. These are discussed in relation to the observation that the rate of aerobic glycolysis in slices from cerebral cortex of young rats was not increased by d -glutamate (5 m m ) and high potassium (50 m m ).     

Study of hyaluronan synthase inhibitor, 4-methylumbelliferone derivatives on human pancreatic cancer cell (KP1-NL)

The structure of 4-methylumbelliferone (MU) consists of coumarin with 4-methyl group and 7-hydroxy group. MU inhibits HA synthesis and pericellular HA matrix formation. In this study, we used 10 MU derivatives which have hydroxy groups and methyl groups at various positions of coumarin to investigate a more effective HA inhibitor than MU. First, human pancreatic cancer cell (KP1-NL) growth assay was analyzed by Alamar Blue to determine the non-toxic concentration of MU derivatives, and the inhibitory effect on HA synthesis in the cell cultures was analyzed by HA measuring kit. Next, cell surfaces of cancer cells were analyzed by particle-exclusion assay. In conclusion, both hydroxy and methyl groups are necessary for HA inhibition by MU, and two hydroxy groups inhibited HA synthesis more strongly than MU.