[PSI] and [URE3] as yeast prions

[URE3] is a non-Mendelian genetic element that mimics recessive mutations in the chromosomal URE2 gene making cells derepressed for nitrogen catabolic enzymes. [PSI] is a non-Mendelian enhancer of readthrough of translational termination similar in its effects to some mutations in the chromosomal SUP35 gene. Three lines of evidence led to the proposal⁷⁵ that both [URE3] and [PSI] are prions, infectious proteins analogous to the scrapie agent mediating transmissible spongiform encephalopathies of mammals. (1) Both [PSI] and [URE3] are reversibly curable. (2) [PSI] propagation requires SUP35 and [URE3] propagation requires URE2 with recessive chromosomal mutants having the same phenotypes as the presence of the respective dominant non-Mendelian element. (3) Overproduction of Sup35p and Ure2p increases the frequency of cells acquiring [PSI] or [URE3], respectively.     

The repression response to implied failure as a function of the hysteria-psychasthenia index.

A study designed to test the Freudian theory of repression and its relation to the scores on the repression index of the hysteria minus the psychasthenia scales of the MMPI. Results were consistent with the repression hypothesis and are also discussed in relation to the drive-anxiety hypothesis. 15 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The repression hypothesis studied in a situation of hypnotically induced conflict.

"Through hypnotic induction and control of conflict and degree of awareness, five experimental conditions were produced: (a) preconflict control; (b) conflict with posthypnotic amnesia for the situation; (c) conflict with partial posthypnotic amnesia; (d) conflict with full awareness; and (e) postconflict control. Eight measures of response to a word-association test administered by the Luria method were obtained for six Ss. Each S was tested in the waking state under the five experimental conditions. For the Ss as a group it was demonstrated that (a) there was a conflict; (b) there was a progressive increase in degree of awareness; and (c) most of the measures of behavior reflected emotional disturbance with some validity." (25 ref.) From Psyc Abstracts 36:01:1HJ04B. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Authoritarianism and repression.

"In an examination of the relationship between repression and authoritarian and ethnocentric attitudes, a group of male freshmen college students filled out the California E and F scales and then participated in an auditory perception experiment in which they were asked to identify a series of noise-masked self-disparaging sexual and aggressive sentences and neutral control sentences. The F scores were significantly related to the perception of sentences in both the sexual and aggressive areas with the more authoritarian men demonstrating poorer recognition accuracy. The E scale, on the other hand, did not prove to be related to perceptual performance." The results were interpreted as indicating stronger repressive tendencies in the authoritarian Ss. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Polyphenols and phenolic acids from strawberry and apple decrease glucose uptake and transport by human intestinal Caco‐2 cells

The effect of polyphenols, phenolic acids and tannins (PPTs) from strawberry and apple on uptake and apical to basolateral transport of glucose was investigated using Caco‐2 intestinal cell monolayers. Substantial inhibition on both uptake and transport was observed by extracts from both strawberry and apple. Using sodium‐containing (glucose transporters SGLT1 and GLUT2 both active) and sodium‐free (only GLUT2 active) conditions, we show that the inhibition of GLUT2 was greater than that of SGLT1. The extracts were analyzed and some of the constituent PPTs were also tested. Quercetin‐3‐O‐rhamnoside (IC₅₀=31 μM), phloridzin (IC₅₀=146 μM), and 5‐caffeoylquinic acid (IC₅₀=2570 μM) contributed 26, 52 and 12%, respectively, to the inhibitory activity of the apple extract, whereas pelargonidin‐3‐O‐glucoside (IC₅₀=802 μM) contributed 26% to the total inhibition by the strawberry extract. For the strawberry extract, the inhibition of transport was non‐competitive based on kinetic analysis, whereas the inhibition of cellular uptake was a mixed‐type inhibition, with changes in both V_max and apparent K_m. The results in this assay show that some PPTs inhibit glucose transport from the intestinal lumen into cells and also the GLUT2‐facilitated exit on the basolateral side.     

Chemical composition of tomato (Lycopersicon esculentum) from Tenerife,the Canary Islands

Chemical composition (moisture, ash, total fibre, protein, glucose and fructose), the taste index and maturity were determined in five tomato cultivars (Dorothy, Boludo, Thomas, Dominique, Dunkan) which were cultivated using intensive, organic and hydroponic methods in Tenerife. The chemical composition was similar to most of the data found in the literature. There were many significant differences in the mean values between the analysed parameters according to the cultivar, cultivation method, region of cultivation and sampling period. Glucose and fructose concentrations were strongly and positively correlated, suggesting the common origin of both sugars. The moisture correlated inversely with the rest of the analysed parameters. Applying a stepwise discriminant analysis (DA), low percentages of correct classifications were obtained according to the cultivar and cultivation methods. The correct classification of the tomato samples improved when the DA was applied to differentiate the tomatoes according to the sampling period.     

Absorption of anthocyanins through intestinal epithelial cells – Putative involvement of GLUT2

Anthocyanins bioavailability is a major issue regarding their biological effects and remains unclear due to few data available on this matter. This work aimed to evaluate the absorption of anthocyanins at the intestine using Caco‐2 cells. Anthocyanin extract, rich in malvidin‐3‐glucoside, was obtained from red grape skins and tested on Caco‐2 cells. The absorption of anthocyanins, in absence or presence of 1% ethanol, was detected by HPLC/DAD/LC‐MS. Our results showed that this transport was significantly increased in the presence of ethanol especially after 60 min of incubation. In addition, cells that were pretreated for 96 h with anthocyanins (200 μg/mL) showed an increase of their own transport (about 50% increase). Expression of glucose transporters sodium‐dependent glucose transporter 1, facilitative glucose transporters 5, and facilitative glucose transporters 2 was assessed by RT‐PCR. It was found that facilitative glucose transporters 2 expression was increased (60%) in Caco‐2 cells pretreated with anthocyanins, by comparison with controls. When the effect of anthocyanin extract on ³H‐2‐deoxy‐D ‐glucose uptake was tested, an inhibitory effect was observed (about 60% decrease). However, the malvidin aglycone was tested and had no effect. In conclusion, anthocyanins could be absorbed through Caco‐2 cells, and can interfere with their own transport and also with glucose intestinal uptake.     

催化氧化法以葡萄糖制取葡萄糖酸镁的研究

用钯／发作催化剂，用空气氧化葡萄糖，制取了葡萄糖酸镁，葡萄糖氧化转化率达95％。研究了葡萄糖浓度、搅拌速度、空气流量、反应温度对葡萄糖催化氧化转化的影响。     

黑曲霉A9葡萄糖氧化酶的提取纯化

为研究葡萄糖氧化酶的酶学性质、催化机理等问题,利用黑曲霉(Aspergillus niger)A9,经发酵、破碎细胞,得到胞内葡萄糖氧化酶,然后经超滤浓缩、硫酸铵盐析、DEAE-纤维素离子交换层析、Sephadex G-100凝胶过滤分离纯化。试验结果表明:通过控制离子交换层析与分子筛层析的具体操作条件,大部分杂蛋白被除去,所得酶蛋白经PAGE电泳鉴定为单一条带,达到电泳纯。测定其比活力为1779.29U/mg,比初始发酵液提高20.13倍。建立了一套操作简单、快速且费用低廉的黑曲霉A9葡萄糖氧化酶的提纯方案。