Cell wall autolytic activities and distribution of cell wall glucanases in Zea mays L. seedlings

Exo- and endo-glucanases mediate specific degradation of cell wall (1,3)(1,4)-beta-D-glucans and these enzymes have been related to auxin-mediated growth and development of cereal coleoptiles. However, their distribution and functions have not been well established in other tissues. In this study the glucanase activities and cell wall autolytic activities of different maize organs were determined. Autolysis assays serve to evaluate the hydrolysis of cell wall polymers in situ by measuring the sugars released from the insoluble cell wall matrix resulting from the action of bound enzymes. Autolytic activities were observed in the cell walls of elongating young leaves, mesocotyl and roots of maize. Wall proteins extracted from all of these structures are enriched in several types of glucanases and other wall polysaccharide hydrolases. These enzymes therefore appear to have a widespread and fundamental role in wall metabolism in growing tissues.     

Flavonoid glycosides of the roots of Glycyrrhiza uralensis

The structure of a flavanone glycoside from the roots of Glycyrrhiza uralensis has been confirmed as 4′-O-[β-d-apio-d-furanosyl-(1 → 2)-β-d-glucopyranosyl]liquiritigenin. In addition, two known flavonoid glucosides, ononin (a minor component) and liquiritin (a major component), were isolated from the same extract.     

Fibrinolysis by urokinase endowed with magnetic property

The activated magnetic modifier was synthesized from magnetite, alpha, omega-dicarboxymethylpoly(oxyethylene) and N-hydroxysuccinimide (Biochem. Biophys. Res. Commun., 145, 908-914, 1987). Urokinase was directly coupled with the activated magnetic modifier to obtain magnetic urokinase. The magnetic urokinase dispersed in saline and exerted high fibrinolytic activity (13.8 X 10(4) IU/mg protein), and was readily recovered from saline by magnetic force of 250 Oe. By applying magnetic force, the urokinase was attracted at our will and local fibrinolysis was achieved on fibrin gel in a petri dish.     

Reversal of CD45R isoform switching in CD8+ T cells.

Both CD4+ and CD8+ T cells express either CD45RA or CD45R0 isoform of CD45R in an exclusive way. Recent reports have shown that CD45RA+ T cells lose CD45RA and gain CD45R0 upon activation. This switching has been suggested to be irreversible although more recently, examples of reversal of CD45R isotype switching in CD4+ T cells have been reported. We report here that freshly isolated unprimed CD8+ T cells, when activated with PHA, temporarily lose CD45RA but reexpress an intermediate level of CD45RA 2-3 weeks after activation with PHA. This reversal seems to take place much more slowly in unprimed CD4+ T cells: the majority of CD4+ T cells that had lost CD45RA and gained CD45R0 remained CD45RA-CD45R0+ in 3 weeks after the stimulation. Also, long-term CD8+ CD45RA+ T cell lines stimulated with PHA or OKT3 showed even more rapid recovery of CD45RA while PPD-specific CD4+ T cell clones retained the original CD45R0 phenotype 3 weeks after stimulation with PPD or PHA.     

Glycyrrhizin Prevents 7-Ketocholesterol Toxicity Against Differentiated PC12 Cells by Suppressing Mitochondrial Membrane Permeability Change

Defects in mitochondrial function participate in the induction of neuronal cell injury. In neurodegenerative conditions, oxidative products of cholesterol are elevated and oxysterols seem to be implicated in neuronal cell death. The present work was designed to study the inhibitory effect of licorice compounds glycyrrhizin and 18β-glycyrrhetinic acid against the toxicity of 7-ketocholesterol in relation to the mitochondria-mediated cell death process. 7-Ketocholesterol induced the nuclear damage, loss of the mitochondrial transmembrane potential, increase in the cytosolic Bax and cytochrome c levels, caspase-3 activation and cell death in differentiated PC12 cells. Glycyrrhizin and 18β-glycyrrhetinic acid prevented the 7-ketocholesterol-induced mitochondrial damage, leading to caspase-3 activation and cell death. The results obtained show that glycyrrhizin and 18β-glycyrrhetinic acid may prevent the 7-ketocholesterol-induced neuronal cell damage by suppressing changes in the mitochondrial membrane permeability.     

UCP2 protects hypothalamic cells from TNF-alpha-induced damage

Uncoupling protein 2 (UCP2) is highly expressed in the hypothalamus; however, little is known about the functions it exerts in this part of the brain. Here, we hypothesized that UCP2 protects hypothalamic cells from oxidative and pro-apoptotic damage generated by inflammatory stimuli. Intracerebroventricular injection of tumor necrosis factor alpha (TNF-alpha)-induced an increase of UCP2 expression in the hypothalamus, which was accompanied by increased expression of markers of oxidative stress and pro-apoptotic proteins. The inhibition of UCP2 expression by an antisense oligonucleotide enhanced the damaging effects of TNF-alpha. Conversely, increasing the hypothalamic expression of UCP2 by cold exposure reversed most of the effects of the cytokine. Thus, UCP2 acts as a protective factor against cellular damage induced by an inflammatory stimulus in the hypothalamus.     

Fibrin membrane endowed with biological function VI. Immobilization of multienzymes of urea cycle

Four enzymes in urea cycle and inorganic pyrophosphatase were immobilized simultaneously into a matrix of fibrin fiber formed from fibrinogen by the concerted action of thrombin and blood coagulation Factor XIII. The immobilized multienzyme system not only had an ability to carry out urea cycle continuously at least over several hours, but also had a greatly improved efficiency over the corresponding soluble system.     

Long-term monitoring of fecal steroid hormones in female snow leopards (Panthera uncia) during pregnancy or pseudopregnancy

Knowledge of the basic reproductive physiology of snow leopards is required urgently in order to develop a suitable management conditions under captivity. In this study, the long-term monitoring of concentrations of three steroid hormones in fecal matter of three female snow leopards was performed using enzyme immunoassays: (1) estradiol-17β, (2) progesterone and (3) cortisol metabolite. Two of the female animals were housed with a male during the winter breeding season, and copulated around the day the estradiol-17β metabolite peaked subsequently becoming pregnant. The other female was treated in two different ways: (1) first housed with a male in all year round and then (2) in the winter season only. She did not mate with him on the first occasion, but did so latter around when estradiol-17β metabolite peaked, and became pseudopregnant. During pregnancy, progesterone metabolite concentrations increased for 92 or 94 days, with this period being approximately twice as long as in the pseudopregnant case (31, 42, 49 and 53 days). The levels of cortisol metabolite in the pseudopregnant female (1.35 μg/g) were significantly higher than in the pregnant females (0.33 and 0.24 μg/g) (P<0.05). Similarly, during the breeding season, the levels of estradiol-17β metabolite in the pseudopregnant female (2.18 μg/g) were significantly higher than those in the pregnant females (0.81 and 0.85 μg/g) (P<0.05). Unlike cortisol the average levels of estradiol-17β during the breeding season were independent of reproductive success.The hormone levels may also be related to housing conditions and the resulting reproductive success in female leopards. The female housed with a male during the non-breeding season had high levels of cortisol metabolites and low levels of estradiol-17β in the breeding season, and failed to become pregnant. This indicates that housing conditions in snow leopards may be an important factor for normal endocrine secretion and resulting breeding success.     

Sustained enhancement of Ca(2+) influx by glibenclamide induces apoptosis in RINm5F cells

Cytosolic Ca(2+) elevations are known to be involved in triggering apoptosis in many tissues, but the effect of sustained enhancement of Ca(2+) influx on apoptosis in beta cells remains unknown. We have found that the viability of RINm5F cells is decreased dose-dependently by continuous exposure to glibenclamide at concentrations from 10(-7) to 10(-4) M, and that this effect is partially ameliorated by pretreatment with cycloheximide. Electrophoresis of the cells exposed to glibenclamide revealed ladder-like fragmentation characteristic of apoptosis, and which also is suppressed by cycloheximide pretreatment. By using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining, we detected increased DNA fragmentation in the nuclei of the cells exposed to glibenclamide, and staining with Hoechst 33342 and propidium iodide showed a dose-dependent increase in the number of cells with the chromatin condensation and fragmentation in their nuclei that is characteristic of apoptosis. The effects of glibenclamide on cell viability and apoptotic cell death were partially inhibited by treatment with Ca(2+) channel blocker, and by reducing the extracellular Ca(2+) concentration during glibenclamide exposure, suggesting that they may be derived from increased Ca(2+) influx. Furthermore, only the percentage of apoptotic cells, and not that of necrotic cells, increased with the increasing intracellular Ca(2+) concentration during glibenclamide exposure. In conclusion, we have demonstrated that the sustained enhancement of Ca(2+) influx caused by glibenclamide exposure can induce apoptotic cell death in a pure beta cell line.