Studies on the thermostability of the α-amylase of Bacillus caldovelox

Summary Molecular mechanisms of thermoinactivation of the thermostable -amylase of Bacillus caldovelox were examined. Monomolecular conformational processes were found to be the major causes of thermoinactivation at both pH 4.5 and 8.0. The enzyme possessed considerable additional thermostability at pH 8.0, with half-lives of 0.75 and 7.0 min at 90° C and pH 4.5 and 8.0, respectively. The amino acid composition was examined with respect to the underlying thermostability exhibited by this enzyme. The inherent thermostability exhibited may be due to the high proline content (4.47 mol%), but more likely due to the high content of residues forming hydrophobic bonds (60.89 mol%) allied to a low content of residues responsible for ionic interactions (28.34 mol%). Offprint requests to: C. T. Kelly     

Effect of Dephosphorylation on the Self-association and the Precipitation of β-Casein

The pyrolyzate of the nondialyzable melanoidin prepared from glucose-ammonia reaction system (kept in pH 5.3~6.0 during the reaction) was fractionated to volatile fraction and nonvolatile fraction. Among the volatile components, two pyridines and four alkylpyrazines were identified. On the other hand, one imidazole compound and two β-hydroxypyridines isolated from the nonvolatile fraction were identified as 4(5)-methylimidazole, 3-hydroxypyridine and 2-methyl-5-hydroxypyridine, respectively. It is inferred that these compounds are not produced by the fission of the main skeleton in the melanoidin molecule, but formed by pyrolysis of the heterocyclic compounds present as a small moiety in the melanoidin.     

Effect of cortisone on the developmental pattern of the neutral and the acid β-galactosidases of the small intestine of the rat

1. The developmental pattern and effect of cortisone on acid beta-galactosidase and neutral beta-galactosidase were studied in postnatal rats by a recently proposed method for their independent determination. 2. After birth the acid beta-galactosidase activity increases in the ileum, whereas it decreases slightly in the jejunum. On day 16 after birth the activity in the ileum decreases and in 20-day-old rats activity in both parts of the intestine decreases to adult values. In suckling animals the activity in the ileum exceeds the jejunal activity severalfold and in adult animals the activity in the jejunum is slightly higher than that in the ileum. 3. Neutral beta-galactosidase activity is high after birth and decreases in both jejunum and ileum after day 20 after birth. In 12-20-day-old rats activity in both parts is essentially the same, but in adult animals jejunal activity exceeds ileal activity four-to five-fold. 4. Cortisone (0.5, 2.0 or 5.0mg/100g body wt. daily for 4 days) does not influence the activity of either enzyme in 60-day-old rats. Acid beta-galactosidase activity is decreased after cortisone treatment in 8-, 12-, 16-and 18-day-old rats, with sensitivity to cortisone increasing with the approach of weaning. No effect of cortisone on acid beta-galactosidase is seen in 8-day-old rats. Neutral beta-galactosidase activity is increased in the ileum of 8-, 12-, 16- and 18-day old rats, but only in the jejunum of 8-and 12-day-old rats.     

Studies on the Fluorescence of Saké

By spectrofluorophotometric investigation on various kinds of Saké it was found that they have at least two kinds of fluorescent colors, the one is blue, the other yellowish green. The former is always more dominant than the latter, but is unstable although the intensities of both color decrease remarkably by treatment of active charcoal. Ferulic acid and harman as the blue fluorescent components are isolated, the former from Saké in young, the latter from Saké kept for a long time under direct sun light.     

Effects of ⁵⁶Fe-particle cranial radiation on hippocampus-dependent cognition depend on the salience of the environmental stimuli

Ionizing radiation reduces the numbers of neurons expressing activity-regulated cytoskeleton-associated protein (Arc) in the hippocampal dentate gyrus (DG). It is currently unclear if that change relates to cognitive function. We assessed the effects of 1 Gy of head-only ??Fe-particle irradiation on hippocampus-dependent and hippocampus-independent fear conditioning and determined how those changes related to Arc expression within the DG. Irradiated mice that did not receive tone-shock pairings on day 1 showed less freezing in the same context on a second day and a lower fraction of Arc-expressing neurons in the free (lower) blade of the DG than sham-irradiated mice. Those data suggested reduced hippocampus-dependent spatial habituation learning. Changes in Arc expression in the free blade correlated positively with freezing in mice that did not receive tone-shock pairings. However, irradiated mice that did receive tone-shock pairings showed enhanced contextual freezing but a reduced percentage of Arc-expressing neurons in the enclosed (upper) blade. Changes in Arc expression correlated negatively with freezing in mice that received tone-shock pairings. In animals receiving cued fear conditioning, radiation did not affect cognitive performance or the fractions of Arc-expressing neurons. While the relationship between Arc expression and cognitive performance is complex, our data suggest that radiation effects on hippocampus-dependent cognition might depend on the prominence (salience) of environmental stimuli and blade-specific Arc expression.     

Effect of the three-dimensional organization of liver cells on the biogenesis of the γ-glutamyltransferase fraction pattern

Context Four gamma-glutamyltransferase (GGT) fractions with different molecular weights (big-, medium-, small- and free-GGT) are detectable in human plasma. Objective Verify if liver cells can release all four GGT fractions and if the spatial cell organization influences their release. Methods Hepatoma (HepG2) and melanoma (Me665/2/60) cells were cultured as monolayers or spheroids. GGT released in culture media was analysed by gel-filtration chromatography. Results HepG2 and Me665/2/60 monolayers released the b-GGT fraction, while significative levels of s-GGT and f-GGT were detectable only in media of HepG2-spheroids. Bile acids alone or in combination with papain promoted the conversion of b-GGT in s-GGT or f-GGT, respectively. Conclusions GGT is usually released as b-GGT, while s-GGT and f-GGT are likely to be produced in the liver extracellular environment by the combined action of bile acids and proteases.     

The dog that didn’t bark: on the effect of the Great Recession on the surge of secessionism

This paper explores the relationship between the economic turmoil generated by the Great Recession and the increase of secessionism. Some authors have stressed that the Great Recession triggered changes in territorial preferences and, in the context of a conflict between the centre and the periphery, fuelled secessionism as a radical shift of the institutional setup. Nevertheless, other researchers have remarked that a recession may enhance the status quo bias and decrease the likelihood of changes. Our paper aims at contributing to this debate by analysing the case of Catalonia. We use an aggregate and an individual-level empirical design to explore the relationship between the deterioration of the economic situation and the increase of preferences for secession among the Catalan population. The findings from the analysis of our empirical models do not support the hypothesis that the effects of the Great Recession had any significant impact on political preferences in Catalonia.     

Studies on the oxidation–reduction systems of the erythrocyte

1. Starvation for 3 days produces a decrease in methaemoglobin-reductase and glutathione-reductase activities, but it does not alter the glucose 6-phosphate-dehydrogenase activity of the rat erythrocyte. 2. The feeding of a protein-free diet for 11 days causes greater changes in the first two enzymes and also a diminution of the third. Under this experimental condition slight decreases in protein and haemoglobin contents were noted. 3. The experimental animals did not show methaemoglobinaemia, probably because the activity of methaemoglobin diaphorase is preserved. 4. The GSH content was not affected but the stability of the tripeptide in the presence of an oxidizing agent was diminished.     

Effect of α-p-chlorophenoxyisobutyrate on the metabolism of isoprenoid compounds in the rat

1. Feeding of alpha-p-chlorophenoxyisobutyrate (CPIB) to rats increased ubiquinone concentration in the liver but not in other tissues. The increase was progressive with the time of feeding and related to the concentration of CPIB in the diet. 2. Incorporation of [1-(14)C]acetate, but not of [2-(14)C]mevalonate, into sterols in the liver in vivo or by liver slices in vitro was decreased on feeding the rats with CPIB. However, incorporation of mevalonate into ubiquinone increased. 3. CPIB, when added in low concentrations to liver slices, had no effect on isoprene synthesis from acetate; higher concentrations, however, were inhibitory. 4. No activation of ubiquinone synthesis from mevalonate was observed when CPIB was added to the liver slices synthesizing ubiquinone. 5. The increase in ubiquinone in CPIB-fed animals appears to be due to increased synthesis in the initial stages and to decreased catabolism in the later stages. 6. An inverse relationship was found between the concentration of ubiquinone in the liver and the serum sterol concentration in CPIB-fed rats.     

Difficulties of assessing the impacts of the 2019–2020 bushfires on koalas

The 2019–2020 Australian bushfires were unprecedented both in extent and severity, impacting wildlife through direct mortality as well as habitat damage. More than 10% of koala habitat is estimated to have been affected by fires. Estimating the number of koalas lost is crucial to assess koala conservation status and to determine the appropriate management actions required. However, this is not a trivial task, as accurate data on koala distribution and population density before the fires is patchy. Acknowledging this weakness, we sought to estimate fire impact on koalas at specific sites, by comparing habitat areas affected by the fire with habitat areas that were unaffected by the fire, pairing closely related study sites (based on geography and vegetation). To compare koala density, we deployed two koala detection methods; drone-acquired thermal imagery and detection dogs coupled with genetic fingerprinting, in four fire-affected sites paired with four control sites in New South Wales and Queensland. Through drone surveys, we detected 140 koalas in 5,240 ha in New South Wales. The detection dogs found 144 scat samples corresponding to 79 unique koalas in 77 ha of transects in Queensland. Our preliminary results show many koalas were still present in fire-affected areas after the 2019–2020 bushfire season. Koala density was 24 to 71% lower in fire-affected sites compared with control sites in three of the habitat pairs, whereas unexpectedly, in the fourth pair, we observed a 317% higher koala density in the fire-affected site. This underlined that koalas can be present in fire-affected areas and that monitoring their health could be critical for months after the fires.     

Effect of progesterone pretreatment on the uptake of estradiol-17β by the uterine epithelium of the rat

Summary Progesterone pretreatment of ovariectomised rats resulted in a moderate (44%) lowering of the level of nuclear estradiol receptors found in the uterine epithelium 2 h after a single injection of this estrogen.     

Effect of Crystallization State on the Gel Properties of Oleogels Based on β-sitosterol

Oleogels based on three different oils (sunflower oil, solid coconut oil and liquid coconut oil) were formulated using β-sitosterol. In general, an observed increase in crystallinity was correlated with an increase in the gel storage modulus and hardness. Addition of lecithin promoted the formation of needle-like crystals of β-sitosterol with a corresponding increase in strain tolerance and oil-trapping capacity for oleogels produced with liquid oils. However, the incorporation of β-sitosterol crystals with or without lecithin into oleogels containing solid coconut oil reduced its strain tolerance by interrupting the formation of continual radiolitic crystal structures. The use of sunflower oil (long chain fatty acids) was more favourable to the packing and growth of gelator crystals and the formation of an elastic gel, in comparison to liquid coconut oil (short chain fatty acids). Overall, the type and physical state of oil influence the formation of oil crystal network, thus affecting its gel properties. These findings allow the better understanding of β-sitosterol-based oleogels, providing opportunity to design for the application as a fat-replacer and lowering solid fat content.