Effects of AMP-activated protein kinase (AMPK) signaling and essential amino acids on mammalian target of rapamycin (mTOR) signaling and protein synthesis rates in mammary cells

Regulation of mammary protein synthesis potentially changes the relationships between AA supply and milk protein output represented in current nutrient requirement models. Glucose and AA regulate muscle protein synthesis via cellular signaling pathways involving mammalian target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK). The objective of this study was to investigate the effects of essential AA (EAA) and acetate or glucose on mTOR and AMPK signaling pathways and milk protein synthesis rates. A bovine mammary epithelial cell line, MAC-T, was subjected to different media containing 0 or 3.5 mmol/L EAA concentrations with 0 or 5 mmol/L acetate or 0 or 17.5 mmol/L glucose in 2 separate 2 × 2 factorial studies. In a separate set of experiments, lactogenic bovine mammary tissue slices were subjected to the same treatments except that the low EAA treatment contained a low level of EAA (0.18 mmol/L). Supplementation of EAA enhanced phosphorylation of mTOR (Ser2448) and eukaryotic initiation factor 4E binding protein 1 (4EBP1, Thr37/46), and reduced phosphorylation of eukaryotic elongation factor 2 (eEF2, Thr56) in MAC-T cells. Concentration of ATP and phosphorylation of AMPK increased and decreased, respectively, in the presence of EAA in MAC-T cells. Acetate, EAA, or glucose numerically reduced AMPK phosphorylation by about 16% in mammary tissue slices. Provision of EAA increased phosphorylation of mTOR and 4EBP1, intracellular total EAA concentration, and casein synthesis rates in mammary tissue slices, irrespective of the presence of acetate or glucose in the medium. Phosphorylation of mTOR had a marginally negative association with AMPK phosphorylation, which was positively related to eEF2 phosphorylation. Casein synthesis rates were positively and more strongly linked to mTOR phosphorylation than the negative link between eEF2 phosphorylation and casein synthesis rates. A 100% increase in mTOR phosphorylation was associated with an increase in the casein synthesis rate of 0.74%·h⁻¹, whereas a 100% increase in eEF2 phosphorylation was related to a decline in the casein synthesis rate of 0.33%·h⁻¹. Although AMPK phosphorylation was responsive to cellular energy status and had a negative effect on mTOR-mediated signals in bovine mammary epithelial cells, its effect on milk protein synthesis rates appeared to be marginal compared with the mTOR-mediated regulation of milk protein synthesis by EAA.     

Psychological profiles of purging bulimics, repeat dieters, and controls.

In Study 1, 29 female undergraduates who met Diagnostic and Statistical Manual of Mental Disorders (DSM-III) criteria for bulimia were compared with 2 nonbulimic groups drawn from the same S pool. One group consisted of 27 Ss who reported feeling dissatisfied with their weight and engaged in repeated dieting attempts but not bulimic behavior. The 2nd comparison group consisted of 27 Ss who reported feeling satisfied with their weight and not dieting within the last year. Measures included the Minnesota Multiphasic Personality Inventory (MMPI), Personal Attributes Questionnaire, and Tennessee Self-Concept Scale. All Ss scored in the normal range, but bulimics scored significantly higher than the 2 comparison groups on a number of clinical scales. Also, the bulimics and repeat dieters reported lower self-esteem than did the nondieting group. The major discriminating variables—psychopathic deviance, mania, and physical self-esteem—separated all 3 groups and accounted for 78% of the explained variance. Study 2 was conducted with 27 current bulimic women, 12 former bulimics, 29 nondieters, and 31 repeat dieters. Results confirm the importance of physical self-esteem and psychopathic deviance in differentiating between groups. This study also revealed that bulimics engaged in sexual activities and in the adolescent acting-out behaviors of drug and alcohol use more frequently, and at an earlier age, than did the 2 comparison groups. Implications for therapeutic interventions are discussed. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attitudes toward sex, arousal, and the retention of contraceptive information.

Previous research has suggested that woman with a negative emotional orientation toward sexuality (i.e., erotophobia) have difficulty learning and retaining sexually relevant material such as contraceptive information. It has been hypothesized that these women become aroused by this material and that this arousal interferes with their ability to learn it. The importance of this issue led us to conduct the current study. Erotophobic and erotophilic women viewed presentations about contraception while their physiological responses were being monitored. In addition, they were tested on the information contained in the presentation before, immediately after, and again 4–6 wks after the presentation. Results indicate that the erotophobic women knew less contraceptive information before the presentation and were more aroused by the presentation. This arousal, however, did not interfere with retention of the material. Results are discussed in terms of individual differences in reactions to sexual material and the ability to learn, retain, and use contraceptive information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Startle reflex inhibition in the rat: Its persistence after extended repetition of the inhibitory stimulus.

Startle reflexes to intense sound bursts are inhibited by weak stimuli that briefly precede their elicitation. In 3 experiments, with 36 Long-Evans hooded rats, the startle stimulus (a 110-db tone burst) was presented 100 msec after the final link in a train of stimuli, the length of the train varying from 1 to 1,000, its repetition rate varying from 1 to 10 per sec, and its constituents being 40 db or 50 db white noise bursts of 25 msec duration. Inhibition was invariant across train length and repetition rate. In Exp IV, the startle stimulus was presented a variable interval after the final link, from 40 to 1,280 msec with 1 or 100 noise bursts (50 db) in the train. Inhibition developed more rapidly following the last member of the 100-stimulus train, suggesting a "priming" or sensitization effect of stimulus repetition, but its overall strength and subsequent rate of decay were not different in the 2 conditions. The general persistence of inhibition following these extended series of stimuli reveals that reflex inhibition must be the outcome of a fixed and obligatory process associated with sensory input. (29 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of sexual motivation on men's risk perception for sexually transmitted disease: There must be 50 ways to justify a lover.

Recent research has incorporated situational factors into assessment of risk. Working from a rational appraisal framework, however, these studies have not emphasized contextual features that might introduce motivated risk assessment. In the current study, participants (N?=?40 male undergraduates) lowered their risk perceptions for STDs following the induction of a sexual motivation. In an initial baseline condition, participants estimated the risk of contracting STDs from partners with relatively high- or low-risk sexual histories. In a subsequent trial, participants repeated the imagery task while viewing photographs that were high or low in sex appeal. As predicted, participants reduced their risk perceptions when they viewed photographs high in sex appeal. The only necessary precondition was the presence of nondiagnostic information from which they could construct biased risk estimates. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A stable photo-electrochemical solar cell employing a CdSe photoanode

Low temperature methods of producing thin coatings of cadmium selenide on a steel substrate are described. These coatings are suitable for solar to electrical energy conversion and have been used in a photoelectrochemical cell employing a cadmium selenide-stabilizing redox couple, which converts sunlight to electricity at a 1% power conversion efficiency without deterioration of the CdSe photoanode.Possible improvements in the coating quality and cell design are considered, and the eventual attainment of a 4% conversion efficiency is considered feasible.     

The effect of barium and cadmium stabilizers on the thermal dehydrochlorination of poly(vinyl chloride): A resonance Raman spectroscopic study

A laser Raman spectroscopic study has been made of the effect of barium and cadmium stabilizers on the thermal dehydrochlorination of poly(vinyl chloride) (PVC). The results obtained indicate that, in terms of the total level of dehydrochlorination, cadmium stearate is not as superior to barium stearate as the visual appearance of the polymer suggests. Also, the level of dehydrochlorination produced in the presence of a mixed stabilizer is not significantly lower than that produced in the presence of barium stearate alone, while samples of the latter exhibit much stronger color. It has also been shown that cadmium stearate can reduce the length of long polyene sequences, presumably by a reaction near the center of such a sequence.     

Influence of commercial corrosion-inhibiting compounds on the atmospheric corrosion of the magnesium alloys EV31A,WE43B,ZE41A and pure magnesium

The influence of four commercial corrosion-inhibiting compounds on the atmospheric corrosion of EV31A, WE43B, ZE41A and pure Mg was studied at two hot, humid, tropical sites for test periods of 3–12 months. LPS 3 and AMLGuard significantly reduced the corrosion rates, with AMLGuard being most effective with inhibition efficiencies above 85%. In contrast, Ardrox 3961 and LPS 2 were ineffective with typical corrosion rates comparable with those of the bare alloys. Corrosion inhibition was tentatively attributed to protective durable barrier films formed by chemical adsorption for LPS 3 and AMLGuard.     

Solubilization of Aromatic Hydrocarbons in Ethylene Oxide-Propylene Oxide Triblock Micelles: Location of Solubilizate and its Effect on Micelle Size from 2D NMR and Scattering Techniques

The solubilization of benzene and toluene in micellar solutions and the effects on the micellization and micelle size of ethylene oxide-propylene oxide triblock copolymers were investigated by dynamic light scattering (DLS), small angle neutron scattering (SANS), and 2D NMR spectroscopy. The copolymeric surfactants have the same size as the middle hydrophobic polypropylene oxide block (Mol. Wt. 3250) and varying polyethylene oxide end blocks (30, 40 and 50%). The solubilization and the properties of the micelles in the presence of the solubilizates were investigated; the results reveal that the more hydrophobic copolymer showed better solubilization. The cloud points of the copolymers decreased in the presence of oils; the depression in the cloud point is due to the formation of an electron donor–acceptor complex. DLS shows that the effect of benzene is dominated at high oil concentration. SANS data show that the micelles remain spherical in shape and that the micellar core size does not change with higher benzene concentration; observed changes in the low scattering vector region could be because of some small amount of benzene clusters formed at higher benzene concentration. Finally, the locus of solubilization of the oils in the copolymer micelles was determined via 2D NMR experiments. In all cases, significant nuclear Overhauser effect spectroscopy (NOESY) cross peaks were observed that appeared to correlate well with the expected loci of these solubilizates in micelles. Hence, the noninvasive NOESY technique provides important information on the location of the aromatic solubilizates in these copolymer micelles that depends on the structure of the oils.     

Pastry Lift and Croissant Volume as Affected by Microbial Transglutaminase

Microbial transglutaminase forms nondisulfide covalent crosslinks in proteins and is increasingly being used in foods. We have previously demonstrated beneficial effects of microbial transglutaminase during breadmaking, which are comparable to traditional oxidizing improvers, hypothesized to act via formation of disulfide crosslinks. Transglutaminase substantially improved the lift of puff pastry. It also had a dramatic effect on the volume of yeasted croissants made with both white flour and a blend of wholemeal and white flour. Furthermore, these effects were preserved after the pastry and croissant doughs had undergone frozen storage for periods of up to 90 d. Transglutaminase, therefore, offers a potential solution to the problem of pastry and croissant dough deterioration on frozen storage.