Comparative study of the mucin-type sugar chains of human chorionic gonadotropin present in the urine of patients with trophoblastic diseases and healthy pregnant women

Human chorionic gonadotropins (hCGs) highly purified from the urine of patients with trophoblastic diseases and of healthy pregnant women contain approximately four mucin-type sugar chains in one molecule. The structures of these sugar chains were studied comparatively by using a new sensitive method to obtain mucin-type sugar chains quantitatively as radioactive oligosaccharides from a small amount of glycoproteins. The mucin-type sugar chains of all hCGs include sialylated and nonsialylated Gal beta 1----3GalNAc and Gal beta 1----4GlcNAc beta 1----6(Gal beta 1----3)GalNAc. In the case of normal hCG and hydatidiform mole hCG, oligosaccharides containing the tetrasaccharide core occupy approximately 10% of the total mucin-type sugar chains. The ratio of the tetrasaccharide containing oligosaccharides is increased prominently to approximately 60% in choriocarcinoma hCG. The proportion in invasive mole hCG was also increased, but less than the proportion of choriocarcinoma hCG.     

Stimulation of uridine phosphorylation in primary cultures of Xenopus laevis hepatocytes by estradiol-17 beta

The effects of estrogen on the uridine uptake into cells were examined in primary cultures of liver parenchymal cells from Xenopus laevis. The total uptake of [3H]uridine into the estrogen-treated cells and its incorporation into RNA were about 1.5 times higher than the values for control cells. The uptake of [3H]adenosine and its incorporation into RNA were not affected by estrogen. An experiment in which liver parenchymal cells were double labeled with [3H]uridine and [3H]adenosine showed that estrogen elevated the specific radioactivity of the UTP pool 1.4-fold the value found for the control cells, but that of the ATP pool was not altered by estrogen. Short term labeling revealed that estrogen did not significantly alter the rate of the initial uptake of [3H]uridine into the cells, but it did stimulate [3H]uridine phosphorylation about 1.7-fold. Uridine kinase activity measured in cell-free extracts of hepatocytes treated with estrogen had a value 1.6 times that of the control cells. These data indicate that the stimulation of [3H]uridine uptake and phosphorylation in Xenopus laevis hepatocytes in the presence of estrogen is caused by the enhancement of uridine kinase activity.     

Concurrent Bursty Behavior of Social Sensors in Sporting Events

The advent of social media expands our ability to transmit information and connect with others instantly, which enables us to behave as “social sensors.” Here, we studied concurrent bursty behavior of Twitter users during major sporting events to determine their function as social sensors. We show that the degree of concurrent bursts in tweets (posts) and retweets (re-posts) works as a strong indicator of winning or losing a game. More specifically, our simple tweet analysis of Japanese professional baseball games in 2013 revealed that social sensors can immediately react to positive and negative events through bursts of tweets, but that positive events are more likely to induce a subsequent burst of retweets. We confirm that these findings also hold true for tweets related to Major League Baseball games in 2015. Furthermore, we demonstrate active interactions among social sensors by constructing retweet networks during a baseball game. The resulting networks commonly exhibited user clusters depending on the baseball team, with a scale-free connectedness that is indicative of a substantial difference in user popularity as an information source. While previous studies have mainly focused on bursts of tweets as a simple indicator of a real-world event, the temporal correlation between tweets and retweets implies unique aspects of social sensors, offering new insights into human behavior in a highly connected world.     

Determination of free sulphite in wine using a microbial sensor

Summary A microbial sensor of immobilized Thiobacillus thiooxidans S3 cells was assembled to determine free sulphite in wine. Sulphite oxidation activity of the immobilized cells was sufficiently high for use even after 3 months storage at 4° C. The sensitivity of this sensor was 116 nA·1·mg^-1 for sulphur dioxide. The relationship between the current decrease and the sulphur dioxide concentration was linear up to 17 mg·1^-1. The sampling rate achieved was 10 min per sample including washing time. This sensor method needed no pretreatment of wine samples, and wines diluted with 5 mM sulphuric acid solution could be directly introduced in the computer-aided analysis system. The pigments in red wine did not disturbed the analysis.     

Genetic characterization of human KB cell lines resistant to epidermal growth factor: Pseudomonas exotoxin conjugates

Pleiotropic human KB cell mutants, selected for resistance to a conjugate of epidermal growth factor with Pseudomonas exotoxin (PE-EGF), were characterized genetically. These mutants have a pleiotropic phenotype, which includes reduced number of EGF receptors and reduced growth rate. Hybrid cells between HeLa D98 and four out of five of these resistant cell lines were more resistant to PE-EGF than hybrids formed between HeLa D98 and parental KB cells. This result indicates that the phenotype of PE-EGF resistance is incompletely dominant in four out of five cases and recessive in one out of five variants. In three separate experiments, transfection of DNA from two of the dominant resistant cell lines resulted in transformation of wild-type KB cells to PE-EGF resistance, confirming the dominant nature of these mutations, which affect levels of EGF receptor in KB cells.     

A method for measuring the amount of retrogradely transported HRP in the rat masseteric motoneuron using Mesulam's HRP histochemical protocol and an image processing system. An investigation of the effect of dopamine receptor antagonists on the retrograde transport of HRP

We developed a method for a determination of the amount of retrogradely transported HRP in the rat masseteric motoneuron using a modification of Mesulam's HRP histochemical protocol and an image processing system combined with a light microscope and a television camera. To test the validity and reproducibility of the new method, a quantitative comparison of the amount of dark blue granules of HRP-product in the cell body of masseteric motor neurons was performed between the right and left trigeminal motor nuclei of 70 rats, which resulted in no significant difference. An additional study used the method was made of the effects of administration of five dopamine receptor antagonists with different biochemical and pharmacologic properties on retrograde transport of HRP in the rat masseteric motoneuron. As a result, chlorpromazine, haloperidol, SCH 23390, and sulpiride significantly enhanced retrograde transport of HRP as against domperidone which showed no significant change in the transport. A possible regulatory system for retrograde transport of HRP in the masseteric motoneuron was discussed in relation to the action of the dopamine receptor.     

Inhibition of ATPase Activity in Pea Plasma Membranes In Situ by a Suppressor from a Pea Pathogen, Mycosphaerella pinodes

A pathogenic fungus of pea, Mycosphaerella pinodes, secretesa so-called "suppressor" in its pycnospore germination fluid.The suppressor blocks the defense responses and induces localsusceptibility (accessibility) in pea plants to agents thatare not pathogenic in pea. The suppressor nonspecifically inhibitsthe ATPase activity in plasma membranes prepared from pea, soybean,kidney bean, cowpea and barley plants. However, cytochemicalstudies by electron microscopy indicate that the suppressorspecifically inhibits the ATPase in pea cell membranes, butnot in those of four other plant species tested. That is, thespecificity of the suppressor appears at the cell and/or tissuelevel, but is not evident in vitro. Furthermore, the inhibitoryeffect of the suppressor is temporary because the ATPase activityrecovers 9 h after the treatment. A similar effect was observedafter inoculation with M. pinodes but not with a nonpathogenof pea, M. ligulicola. The role of the suppressor in host-parasitespecificity is discussed. (Received April 9, 1991; Accepted August 6, 1991)     

Biosynthesis of lysosomal cathepsins B and H in cultured rat hepatocytes

The biosynthesis of lysosomal cysteine proteases, cathepsins B and H, was investigated by using pulse-chase experiments in vivo in primary cultures of rat hepatocytes. Cathepsins B and H were isolated from either total cell extracts or culture medium labeled with [35S]methionine by immunoprecipitation and analyzed for their molecular forms. Within 60 min of chase, cellular proforms of cathepsins B of 39 kDa and H of 41 kDa were converted to single-chain form cathepsins B of 29 kDa and H of 28 kDa, respectively, and persisted as these forms even after 12-h chase periods. The proforms of cathepsins B and H derived from pulse-labeling experiments showed complete susceptibility to endoglycosidase H treatment, indicating that these proenzymes bear high-mannose-type oligosaccharides at the stage of initial events of biosynthesis. In the presence of tunicamycin, unglycosylated proenzymes of cathepsins B of 35 kDa and H of 34 kDa were found to be secreted into the extracellular medium without undergoing proteolytic processing. Furthermore, in the presence of swainsonine, a potent inhibitor of Golgi mannosidase II, considerable amounts of the proenzymes were secreted and accumulated in the medium during chasing periods. These results suggest that the oligosaccharide moiety of these enzymes would be necessary for the intracellular sorting mechanism. In monensin-treated cells, the conversion of intracellular proenzymes to mature enzymes was significantly inhibited and the proenzymes were secreted into the medium. In the presence of chloroquine or ammonium chloride, proteolytic processing of the proenzymes was completely prevented and the enhanced secretion of proenzymes was observed. These results suggest that in the presence of lysosomotropic amines the intracellular sorting of proenzymes might not occur properly during biosynthesis.     

Insulin-degrading enzyme is capable of degrading receptor-bound insulin

In the investigation of the intracellular sites of insulin degradation, it might be important whether receptor-bound insulin could be a substrate for insulin-degrading enzyme (IDE). Insulin receptor and IDE were purified from rat liver using a wheat germ agglutinin column and monoclonal anti-IDE antibody affinity column, respectively. [125I]insulin-receptor complex was incubated with various amounts of IDE at 0 degree C in the presence of disuccinimidyl suberate and analyzed by reduced 7.5% SDS-PAGE and autoradiography. With increasing amounts of IDE, the radioactivity of 135 kd band (insulin receptor alpha-subunit) decreased, whereas that of 110 kd band (IDE) appeared then gradually increased, suggesting that IDE could bind to receptor-bound insulin. During incubation of insulin-receptor complex with IDE at 37 degrees C, about half of the [125I]insulin was dissociated from the complex. However, the time course of [125I]insulin degradation in this incubation was essentially identical to that of free [125I]insulin degradation. Cross-linked, non-dissociable receptor-bound [125I]insulin was also degraded by IDE. Rebinding studies to IM-9 cells showed that the receptor binding activity of dissociated [125I]insulin from insulin-receptor complex incubated with IDE was significantly (p less than 0.001) decreased as compared with that without the enzyme. These results, therefore, show that IDE could recognize and degrade receptor-bound insulin, and suggest that IDE may be involved in insulin metabolism during receptor-mediated endocytosis through the degradation of receptor-bound insulin in early neutral vesicles before their internal pH is acidified.     

Glucosylation of Salicyl Alcohol by Gardenia jasminoides Cell Cultures

Cultured cells of Gardenia jasminoides produced both salicinand isosalicin from exogenously supplied salicyl alcohol. Theglucosylation activity of the cells was highest in the exponentialphase of growth and ca. 70% of the added substrate was convertedto the glucosides within 4 days. The rate of glucosylation wasalso dependent on the medium composition such as auxin and sucroseconcentrations. The ratio of salicin to isosalicin formed fromsalicyl alcohol was influenced by the growth stage of the culturedcells. Salicin was converted to isosalicin when exogenouslyadded to the culture. (Received October 11, 1985; Accepted March 10, 1986)