Nucleation and growth of elastin-like peptide fibril multilayers: an in situ atomic force microscopy study

Controlling how molecules assemble into complex supramolecular architectures requires careful consideration of the subtle inter-?and intra-molecular interactions that control their association. This is particularly crucial in the context of assembly at interfaces, where both surface chemistry and structure can play a role in directing structure formation. We report here the results of a study into the self-assembly of the elastin-like peptide EP I on structurally modified highly ordered pyrolytic graphite, including the role of spatial confinement on fibril nucleation and the growth of oriented fibril multilayers. In situ atomic force microscopy performed in fluid and at elevated temperature provided direct evidence of frustrated fibril nuclei and oriented growth of independent fibril domains. These results portend the application of this in situ strategy for studies of the nucleation and growth mechanisms of other fibril-?and amyloid-forming proteins.     

Psychopathology and Marital Satisfaction: The Importance of Evaluating Both Partners.

Using path analysis and hierarchical linear modeling, the authors evaluated the associations between both partners' level of depression and anxiety, as measured by Minnesota Multiphasic Personality Inventory-2 (MMPI-2) content scales, and both partners' level of marital satisfaction among married couples (N = 774) that participated in the MMPI restandardization study (J. N. Butcher, W. G. Dahlstrom, J. R. Graham, A. Tellegen, & B. Kaemmer, 1989). Results indicated that marital satisfaction was predicted by the person's own level of anxiety and depression (i.e., actor effects) and by his or her spouse's level of depression only (i.e., partner effects). Findings also indicated that (a) there were no significant gender differences in the magnitude of effects, (b) depression effects were significantly stronger than anxiety effects, (c) actor effects were significantly stronger than partner effects, and (d) there were interactions between actor and partner effects for depression only. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lateralized changes in tympanic membrane temperature in relation to different cognitive tasks in chimpanzees (Pan troglodytes).

Lateralized changes in tympanic membrane (TM) temperature were assessed in chimpanzees. Subjects were engaged in 1 of 3 different cognitive tasks, including matching-to-sample, visual-spatial discrimination, and a motor task. During execution of each task, TM temperatures were taken from each ear over a 20-min time period. The TM temperatures at each time interval were subtracted from a baseline measure to assess relative change in blood flow. For the matching-to-sample and visual-spatial discrimination tasks, significant lateralized changes in TM temperature were found, with left-ear temperature increasing and right-ear temperature decreasing. No laterality effects were found for the motor or control tasks. These data provide the first evidence of laterality in physiological functioning in chimpanzees and suggest that transient asymmetries in cognitive functions are associated with changes in cerebral blood flow as assessed by TM temperature change. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synergistic effects of metals and oxidants in the curing of marine mussel adhesive

Marine mussels produce an impressive adhesive material for affixing themselves to rocks in the turbulent marine environment. This glue is generated by application of proteins to the surface followed by extensive cross-linking to yield the final matrix. Prior studies have shown that simple oxidation or reactivity brought about by metal ions may be key to this protein cross-linking process. Here we have explored protein cross-linking reactivity in which combinations of metals and oxidants may display synergistic effects with respect to adhesive curing. Extracted adhesive proteins were mixed with a series of metals, oxidants, and combinations thereof. In some cases, synergistic curing was observed. For example, we found that iron(II) ions with hydrogen peroxide brought about a greater degree of protein cross-linking than the sum of the individual components. These studies were performed as part of our efforts to provide perspectives on the connections between biology, chemistry, and functional materials.     

Apolipoprotein B mRNA editing and apolipoprotein gene expression in the liver of hyperinsulinemic fatty zucker rats: Relationship to very low density lipoprotein composition

We previously demonstrated increased apolipoprotein B (apoB) mRNA editing, elevated levels of mRNA for the catalytic component of the apoB mRNA editing complex, apobec-1, and increased secretion of the product of the edited mRNA, apoB48, in very low density lipoproteins (VLDL) in primary cultures of Sprague-Dawley rat hepatocytes following insulin treatment. In order to determine the effect of in vivo hyperinsulinemia on these processes, we determined apoB mRNA editing, apobec-1 expression, hepatic expression of mRNA for apoB and other VLDL apoproteins, and the quantity and composition of plasma VLDL in the hyperinsulinemic fatty Zucker rat. Total apoB mRNA content of the livers of the fatty rats and lean littermates did not differ, however, edited apoB message coding for hepatic apo B48, and abundance of mRNA for the catalytic subunit of the apoB mRNA editing complex, apobec-1, was increased by 1.7-and 3.3-fold, respectively, in fatty rats. ApoCIII mRNA abundance was increased in livers of fatty rats as well, but the abundance of hepatic apoE mRNA in the fatty animal was not different from that of the lean rat. Hepatic apoAI mRNA abundance was also increased in the fatty rats. Associated with increased apoB mRNA editing, was the 1.7-fold increase in the fraction of apoB in plasma as apoB48 in fatty rats. VLDL-triglyceride and-apoB in plasma were 15-and 3-fold higher, respectively, in fatty Zucker rats compared to lean littermates, indicating both enrichment of VLDL with triglycerides and increased accumulation of VLDL particles. Increased hepatic expression of mRNA for apoCIII and apoAI was associated with increased content of apoC (and relative depletion of apoE) in VLDL of fatty rats, and plasma apoAI was increased in fatty Zucker rats, primarily in the HDL fraction. The current study provides further evidence that chronic exposure to high levels of insulin influences both the quantity of and lipid/apoprotein composition of VLDL in plasma. The increased apoC and decreased apoE (as well as increased triglyceride) content of VLDL in the fatty Zucker rat observed in the current study may affect VLDL clearance and therefore may be a factor in the observed accumulation of VLDL in the plasma of the fatty hyperinsulinemic Zucker rats.     

Attributional style and depressive symptoms among children.

The reformulation of helplessness theory proposes that an insidious attributional style accompanies and predisposes depressive symptoms. The present study investigated predictions of the reformulation among 96 8–13 yr olds who completed the Children's Attributional Style Questionnaire (ASQ) and Children's Depression Inventory twice, 6 mo apart. 83 of their parents completed the adult ASQ and the Beck Depression Inventory at their children's 2nd testing. Children who attributed bad events to internal, stable, and global causes were more likely to report depressive symptoms than were children who attributed these events to external, unstable, and specific causes. This depressive attributional style predicted depressive symptoms 6 mo later, suggesting that it may be a risk factor for depression. Children's attributional style for bad events and their depressive symptoms converged with those of their mothers but not their fathers. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Confirming the latent structure and base rate of schizotypy: A taxometric analysis.

P. E. Meehl's (1962, 1990) model of schizotypy and the development of schizophrenia implies that the structure of liability for schizophrenia is dichotomous and that a "schizogene" determines membership in a latent class, or taxon (Meehl and R. R. Golden, 1982). The authors sought to determine the latent structure and base rate of schizotypy. They applied Meehl's (1973) MAXCOV-HITMAX taxometric analytic procedures to a subset of items from the Perceptual Aberration Scale (PAS; L. J. Chapman et al, 1978), a prominent psychometric index of schizotypy, derived from a randomly ascertained nonclinical sample (N?=?1,093). The results, in accordance with Meehl's conjectures, strongly suggest that schizotypy, as assessed by the PAS, is taxonic at the latent level with a general population taxon base rate of approximately .10. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Temporal contrast and the word frequency effect.

Studied the word frequency effect in recall and recognition under 3 list structures: (a) homogeneous rare or common nouns, (b) mixed alternating frequencies, and (c) mixed blocked frequencies. Exp I with 96 undergraduates found that the number of frequency contrasts within a list had a clear effect on recall and little effect on recognition. Recall of rare items was poor in a homogeneous list, equal to common items in a blocked list, and better than common items when in a list of alternating frequencies. Exp II with 48 Ss examined the reversed frequency effect of the alternating list under overt and covert rehearsal conditions across 3 trials. Under overt rehearsal there was no significant difference in number of rehearsals of rare and common items. The superior recall of rare items present on Trial 1 decreased across trials supporting a stimulus change-contrast interpretation of the effect of mixed frequency items in free recall. (French summary) (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of psychotherapy on the productivity of psychologists.

To investigate (a) the effects of psychotherapy on the scientific publications of American psychologists and (b) the extent to which this group had received psychotherapy, questionnaires were sent to all APA members receiving PhDs 1945-1951 to obtain information about their therapy. A number of publications was obtained from the Psychological Abstracts. There were no significant differences in number of publications between therapy and matched nontherapy control samples. Of 966 male psychologists responding, ? had received psychotherapy, with clinicians disproportionately represented. Of this ?, 13% had 3 or more therapeutic experiences. There was a high positive correlation between duration of therapy and therapy satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)