Cysteine protease activity in bovine milk

Proteolytic activity of native cysteine proteases was studied in bovine milk. Five fractions (fI–fV) with cysteine protease activity were separated from acid whey prepared from raw bovine milk by ion-exchange chromatography on Q-Sepharose. The hydrolytic action of the most active fractions (fIII and fV), after further purification using gel permeation chromatography on Superdex S75, was studied against individual caseins. The two fractions contained different cysteine protease activities capable of hydrolyzing both α_s1- and β-casein. Studies of the effects of different reagents on the activity of partially purified fIII showed that the activity in this fraction was unaffected by aprotinin, slightly inhibited by p-chloromercuribenzoate and o-phenanthroline and completely inhibited by -trans-epoxysuccinyl- -leucylamido (4-guanidino) butane, consistent with identification as a cysteine protease. Phenylmethylsulphonyl fluoride and pepstatin A reduced activity of fIII by 40% and 50%, respectively. The partially purified fIII retained 20% of its cysteine protease activity after heating at 55°C, 60°C, 65°C and 72°C for 40 min, 20 min, 10 min and 30 s, respectively. Immunoblotting of fIII with antibodies to the bovine lysosomal cysteine protease, cathepsin B, clearly indicated the presence of immunoreactive cathepsin B in this fraction. This study presents strong evidence for the presence of a heterogeneous group of cysteine proteases in bovine milk, with one of these enzymes probably being cathepsin B.     

Wall reflection issues for optical diagnostics in fusion devices

The problem of light reflection has been raised as a high priority issue for optical diagnostics in next step fusion devices where metallic wall environment will generate significant perturbations in the diagnostics measurements. Tore Supra is a large size tokamak equipped with water-cooled stainless-steel panels used to sustain the plasma long shot radiations. These panels are highly reflective and affect significantly optical systems. In particular, we show that the infrared imaging diagnostic, which surveys the plasma facing component surface temperature for safety purposes, can give incorrect information due to reflected light coming from the bottom limiter. In the visible range, motional Stark effect and Zeff measurements experience important drifts during the plasma heating phases due to parasitic light coming from the limiter, but also from the plasma itself when the viewing lines are facing the reflecting walls. In the next step fusion devices such as ITER, the possibility to use optical measurements needs to be accessed by a modeling of the diagnostic light in its machine environment and the development of new techniques of online correction.     

Soft x-ray tomography for real-time applications: present status at Tore Supra and possible future developments

This paper is focused on the soft x-ray (SXR) tomography system setup at Tore Supra (DTOMOX) and the recent developments made to automatically get precise information about plasma features from inverted data. The first part describes the main aspects of the tomographic inversion optimization process. Several observations are made using this new tool and a set of shape factors is defined to help characterizing the emissivity field in a real-time perspective. The second part presents a detailed off-line analysis comparing the positions of the magnetic axis obtained from a magnetic equilibrium solver, and the maximum of the reconstructed emissivity field for ohmic and heated pulses. A systematic discrepancy of about 5 cm is found in both cases and it is shown that this discrepancy increases during sawtooth crashes. Finally, evidence of radially localized tungsten accumulation with an in-out asymmetry during a lower hybrid current drive pulse is provided to illustrate the DTOMOX capabilities for a precise observation of local phenomena.     

The Good,the Bad,and the Expert: How Consumer Expertise Affects Review Valence Effects on Purchase Intentions in Online Product Reviews

This study aims to shed more light on the question whether, and under what circumstances, valence affects consumers' intention to buy a product after reading an online review. We hypothesize that receiver expertise could possibly moderate (a) the impact of review valence on consumers' purchase intentions, and (b) the asymmetric effects of positive and negative reviews. To test these hypotheses, we conducted an experiment, exposing participants (n = 470) to reviews varying in valence (i.e., positive, neutral, negative), with purchase‐intention as the dependent variable. The results support the moderating role of receiver expertise for both the influence and weight of review valence effects. This explains the inconsistent results for review valence reported in previous studies.     

Fluctuations in human milk long-chain PUFA levels in relation to dietary fish intake

Within the Danish population, milk DHA (22∶6n−3) levels vary by more than a factor of 10. This paper deals with fluctuations in the milk content of 22∶6n−3 and other long-chain PUFA (LCPUFA) and the acute effects of fish meals and fish oil supplements on milk levels of LCPUFA. Twelve fish-eating mothers with 4-mon-old infants provided one blood and one adipose tissue sample, and seven consecutive morning hindmilk samples with dietary records from the previous days. Another 12 lactating women were given fish oil (2–8 g) for breakfast and delivered 6–12 milk samples during the following 24 h. The mean milk 22∶6n−3 content of the fish-eating mothers was 0.57±0.28 FA% (=percentage of total area of FAME peaks in GLC) and the day-to-day variation (SD/mean) within the individual was 35±17%. Mean milk 22∶6n−3 content on mornings with no fish the day before was 0.42±0.15 FA%; this was increased by 82±17% (n=9, P=0.05) if the mother had eaten fatty fish. Fish oil resulted in a twofold increase in milk 22∶6n−3 levels, which peaked after 10 h and lasted for 24 h. The EPA content of milk was also increased by fish meals and fish oil supplements, but these had no effect on the level of arachidonic acid. The study showed that diurnal and day-to-day fluctuations in levels of milk n−3 LCPUFA are large, which makes it difficult to assess the 22∶6n−3 intake of breast-fed infants from a single milk sample. In studies of the functional outcome of dietary 22∶6n−3 in breast-fed infants it is suggested also to use a measure of maternal 22∶6n−3 status.     

Identification of peptides in milk as a result of proteolysis at different levels of somatic cell counts using LC MALDI MS/MS detection

The somatic cell count (SCC) in milk is associated with increasing proteolytic degradation of caseins and it has been suggested that enzymes derived from somatic cells contribute to a lower yield and poorer quality of cheese. It is essential to increase the knowledge on naturally occurring milk proteinase activities to better understand how to improve the technological quality of milk. The aim of this work was to identify peptides actually present in milk as a result of proteolysis at different levels of SCC and to assign these peptides to potential responsible proteases where possible. Peptide fractions were prepared from acid whey by ultrafiltration at a molecular cut-off value of 10 000 Da. The peptides were separated using capillary reversed phase high performance liquid chromatography (RP-HPLC) and identified by matrix-assisted laser desorption/ionization-time of flight tandem mass spectrometry (MALDI-TOF MS/MS). Peptides identified ranged in mass from 1023 to 2000 Da, and originated from alphaS1-, alphaS2- or beta-casein. Possible responsible proteases that could be suggested when examining the peptide cleavage sites included plasmin, cathepsin B, D and leukocyte elastase. The results indicated that plasmin was primarily responsible for the observed proteolysis in milk at low cell count, whereas the cathepsins and elastase became implicated at elevated cell count. Specificity and activity of cathepsins and elastase has earlier mainly been studied in model systems, whereas less is known about their activities in milk itself. This is also the first indication of involvement of elastase in milk proteolysis through the unequivocal determination of cleavage sites.     

Preliminary results of a video-assisted psychotherapist workshop in alliance strategies.

This study examined the preliminary results of an integrative, video-assisted training workshop aimed at helping psychotherapists build strong therapeutic relationships with their clients. Participants were 57 clinicians across five community mental health clinics, who were randomly assigned to the brief alliance-training workshop (in which they participated prior to starting treatment with a new client) or to a delayed-training control condition. Outcomes assessed included therapist-reported use of alliance strategies during Session 1, therapist-rated alliance quality after Session 1, and client engagement across the first 4 weeks. In contrast to hypotheses, one-way analyses of variance and chi-square analyses revealed no statistically significant differences between the training and the delayed-training conditions. However, the therapist-reported impact of using the workshop's alliance strategies was positively correlated with therapist-rated alliance quality (r = .30, p = .03) and marginally correlated with number of sessions attended (r = .25, p = .06) across the two conditions. The findings hold promise for the utility of a brief alliance-focused workshop, and for collaborations between researchers and clinicians seeking to bridge science and practice. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Maternal Intake of Fish Oil but not of Linseed Oil Reduces the Antibody Response in Neonatal Mice

Dietary levels of n-3 PUFA are believed to influence the immune system. The importance of the source of n-3 PUFA is debated. This study addressed how the content and source of n-3 PUFA in the maternal diet influenced tissue FA composition and the immune response to ovalbumin (OVA) in mice pups. From the day of conception and throughout lactation, dams were fed diets containing 4% fat from linseed oil (LSO), fish oil (FO) or a n-3 PUFA-deficient diet (DEF). Pups were injected with OVA within 24 h of birth and sacrificed at weaning (day 21). Overall, the content of n-3 PUFA in milk, liver and spleen reflected the source and only minor differences were observed in brain phospholipid 22:6n-3. The source had only limited influence on the n-3 PUFA accretion in peripheral tissue, with most pronounced differences in the spleen. The marine PUFA-group had reduced levels of total OVA-specific antibodies and OVA-IgG1 titers in the pup blood, while the response in the LSO-group did not differ from that in the DEF-group. There were no statistical differences in the cytokine responses to OVA-stimulated splenocytes, but the decrease in IgG1 was paralleled by an increase in IFNγ-production and a decrease in IL-6-production. Our results indicate that maternal intake of FO, but not of LSO, changes the offspring’s antigen-specific response and potentially increases Th1-polarization.