Diurnal change of tartrate dissimilation during the ripening of grapes

l(+)-tartrate-[U-¹⁴C] or sucrose-[U-¹⁴C] was fed into grape berries and ¹⁴CO₂ evolution was determined. ¹⁴CO₂ evolution front l(+)-tartrate-[U-¹⁴C] was slightly higher in mature than immature berries, and that from sucrose-[U-¹⁴C] was higher in immature than mature ones. ¹⁴CO₂ evolution from l(+)-tartrate-[U-¹⁴C] was irregular throughout the day until 2 or 3 weeks after flowering. This stage shifted to regular ¹⁴CO₂ evolution until 6 or 7 weeks after flowering, and the mode of ¹⁴CO₂ evolution showed diurnal variation; higher in the day than at night. Then the stage without variation of ¹⁴CO₂ evolution followed 10 weeks after flowering. These observations indicate that tartrate is not biochemically inert in grape berries, while the amount of ¹⁴CO₂ evolution from sucrose-[U-¹⁴C] was higher at night than in the day through the whole ripening process, except in the early stage.     

Studies on the substrate specificity of Taka-amylase A. XII. Investigation of the active site of Taka-amylase A by examining the properties of p-phenylazobenzoyl Taka-amylase A.

1. When p-phenylazobenzoyl Taka-amylase A (PhAB-TAA) was incubated at pH 6.5 with hydroxylamine for 3 hr at 20degrees, some of the p-phenylazobenzoyl residues that had been introduced into Taka-amylase A (TAA) [1, 4-alpha-D-glucan glucanohydrolase, EC 3.2.1.1, Aspergillus oryzae] were liberated as a hydroxamic acid, and the activity pattern of PhAB-TAA changed to that of intact TAA. This result suggested that the p-phenylazobenzoyl residues liberated had been bound to the tyrosyl residue located near the active site in the enzyme. 2. The transferase action of TAA or PhAB-TAA was studied using phenyl alpha-maltoside as a substrate and maltotritol as an acceptor. Unlike intact TAA, PhAB-TAA was not able to transfer the maltose residue to maltotritol, and this suggested that the p-phenylazobenzoyl residue was located near one of the aglycone-binding subsites, causing steric hindrance.     

Clinical study on early changes in thyroid function of hyperthyroidism treated with propylthiouracil and a relatively small dose of iodide.

In order to compare the acute effects of three kinds of antithyroid agents of iodide (I-), propylthiouracil (PTU) and PTU combined with iodide (PTU+I-) on thyroid function in hyperthyroid patients with diffuse goiter, serum concentrations of thyroxine (T4), triiodothyronine (T3), T3-resin sponge uptake (T3-RU) and free thyroxine index (FT4I) were employed as thyroid function parameters. In the group given iodine (1 mg/day) as iodinated-lecithine, the initial values of T4, T3, T3-RU and FT4I were 20.9 +/- 1.6 microng/100 ml (T4), greater than 740 ng/100 ml (T3), 49.5 +/- 2.3% (T3-RU) and 14.7 +/- 1.8 (FT4I). At the end of one week of therapy, they decreased clearly to 15.6 +/- 2.2 microng/100 ml, 457 +/- 87 ng/100 ml, 42.2 +/- 4.0% and 9.7 +/- 2.4. The so-called "escape phenomenon" from iodide inhibition was observed in serum T4, T3-RU and FT4I values at the end of two weeks of iodide therapy, while serum T3 continued to decrease but the value of T3 was far outside of the normal range. In the PTU group (300 mg/day), thyroid function parameters were 22.5 +/- 0.8 microng/100 ml (T4), greater than 592 ng/100 ml (T3), 54.9 +/- 1.0% (T3-RU) and 18.7 +/- 1.0 (FT4I) before treatment. They decreased continually week by week. At the end of four-week treatment with PTU, the value of each thyroid function parameter was 11.1 +/- 1.9 microng/100 ml, 229 +/- 56 ng/100 ml, 36.6 +/- 4.4% and 5.7 +/- 1.7. In the group of hyperthyroidism simultaneously given both PTU and iodide (300 mg/PTU and 1 mg/iodine), these thyroid function parameters decreased as well as in the group treated with PTU alone for more than two weeks. More rapid or significant decrease of T4, T3, T3-RU and ft4i in PTU+I- group than in PTU group was observed in the present study. These results suggested strongly that iodide alone was not an adequate therapy for hyperthyroidism as well known and they were also compatible with the idea that the concomitant administration of PTU and iodide was more effective in the early phase of therapy of hyperthyroidism than PTU alone.     

Hydroxylations of substituted naphthalenes by Escherichia coli expressing aromatic dihydroxylating dioxygenase genes from polycyclic aromatic hydrocarbon-utilizing marine bacteria

Bioconversion experiments of various mono- or di-substituted naphthalenes such as dimethylnaphthalenes were carried out using the cells of Escherichia coli that expressed aromatic dihydroxylating dioxygenase genes (phnA1A2A3A4 and phdABCD) from polycyclic aromatic hydrocarbon-utilizing marine bacteria, Nocardioides sp. KP7 and Cycloclasticus sp. A5, respectively. We found that the former dioxygenase PhnA1A2A3A4 had broad substrate preference for these compounds and often was able to hydroxylate their methyl groups. Specifically, 1,4-dimethylnaphthalene was predominantly bioconverted into 1,4-dihydroxymethylnaphthalene.     

cDNA cloning and characterization of an osmotically sensitive TRP channel from ascidian eggs

The transient receptor potential (TRP) ion channels are thought to be involved in the entry of calcium ion into cells. In this study, we isolated a cDNA clone, HrTRPV, that shows high homology to Caenorhabditis elegans OSM-9, a TRPV subfamily member of the TRP family, from a Halocynthia roretzi fertilized egg cDNA library. We analyzed its properties using HrTRPV-transfected cells. Upon reduction of extracellular osmolarity, the intracellular calcium concentration was found to increase in HrTRPV-transfected cells. This increase in intracellular calcium concentration was dependent on the presence of extracellular calcium ion and was inhibited by treatment with gadolinium ion, a stretch-activated calcium channel blocker. Thus, these results indicate that ascidian egg HrTRPV is an osmotically sensitive TRP channel.     

Human placenta beta-galactoside-binding lectin. Purification and some properties

A beta-galactoside-binding lectin was extracted from human placenta homogenate with lactose solution and purified to apparent homogeneity by affinity chromatography on asialofetuin-Sepharose. The apparent subunit molecular weight of the lectin was 13,800 and its isoelectric point was about 5. Several saccharides containing D-galactose inhibited the hemagglutinating activity. The lectin resembles other vertebrate beta-galactoside-binding lectins in various biochemical characteristics.     

Bio-medico-mechanical behavior of natural artery blood vessel under constant and variable internal pulsatile pressure flow test in vitro

Studies have been carried out on the bio-medico-mechanical behavior in vitro of natural blood vessel (dogs) under constant and variable internal pulsatile pressure flow. The apparatus designed by us well simulated the arterial system. The studies were made for the case of pressure amplitude kept as constant, of the two-step-multi-duplicated pulsatile pressure and of the fluctuating pressure. For the case of the fluctuating pressure, the strength of the artery becomes considerably lower than those under constant amplitude and two-step-multi-duplicated pulsatile pressure. SEM observations of the inner walls of the artery shows that collagen fibers are more elongated under fluctuating pulsatile pressure flow. In conclusion, in order to avoid the mechanical deterioration of the artery strength, it is useful to keep the pulsatile blood pressure at constant amplitude. Even for the case of the blood pressure fluctuation, it is necessary to manage to keep the blood pressure as near a regular wave as possible, the total number of repeated pulse being equal.     

Two discrete events, human T-cell leukemia virus type I Tax oncoprotein expression and a separate stress stimulus, are required for induction of apoptosis in T-cells

Apoptosis, or programmed cell death, is a key event in biologic homeostasis but is also involved in the pathogenesis of many human diseases including human immunodeficiency virus (HIV) infection. Although multiple mechanisms contribute to the gradual T cell decline that occurs in HIV-infected patients, programmed cell death of uninfected bystander T lymphocytes, including CD4+ and CD8+ T cells, is an important event leading to immunodeficiency. The HIV envelope glycoproteins (Env) play a crucial role in transducing this apoptotic signal after binding to its receptors, the CD4 molecule and a coreceptor, essentially CCR5 and CXCR4. Depending on Env presentation, the receptor involved and the complexity of target cell contact, apoptosis induction is related to death receptor and/or mitochondria-dependent pathways. This review summarizes current knowledge of Env-mediated cell death leading to T cell depletion and clinical complications and covers the sometimes conflicting studies that address the possible mechanisms of T cell death.