BackgroundNon-histone protein acylation is increasingly recognized as an important posttranslational modification, but little is known as to the biochemical properties of protein serine acylating enzymes.Methodology/Principal FindingsWe here report that we have identified a metal-stimulated serine octanoyltransferase activity in microsomes from human erythroleukemic (HEL) cells. The HEL acylating enzyme was linear with respect to time and protein, exhibited a neutral pH optimum (stimulated by cobalt and zinc), and inhibited by chelating reagents. Hydroxylamine treatment removed most, but not all, of the attached radioactivity. A salt extract of microsomal membranes contained the major portion of enzyme activity, indicating that this acyltransferase is not an integral membrane protein. Sucrose density fractionation showed that the acyltransferase activity is concentrated in the endoplasmic reticulum. In competition experiments, the acyltransferase was well inhibited by activated forms of fatty acids containing at least eight to fourteen carbons, but not by acetyl CoA. The zinc-stimulated HEL acyltransferase did not octanoylate proenkephalin, proopiomelanocortin, His-tagged proghrelin, or proghrelin lacking the amino-terminal His-tag stub of Gly-Ala-Met. The peptides des-acyl ghrelin and ACTH were also not acylated; however, des-acyl ghrelin containing the N-terminal tripeptide Gly-Ala-Met was acylated. Mutagenesis studies indicated a requirement for serine five residues from the amino terminus, reminiscent of myristoyl transferase, but not of ghrelin acylation. However, recombinant myristoyl transferase could not recapitulate the hydroxylamine sensitivity, zinc-stimulation, nor EDTA inhibition obtained with HEL acyltransferase, properties preserved in the HEL cell enzyme purified through four sequential chromatographic steps.Conclusions/SignificanceIn conclusion, our data demonstrate the presence of a zinc-stimulated acyltransferase activity concentrated in the endoplasmic reticulum in HEL cells which is likely to contribute to medium-chain protein lipidation.

The purpose of the study was to investigate the seasonal relationship of athletic amenorrhea and body composition in elite, adolescent, cross-country runners. The participants consisted of 28 female adolescent cross-country runners (mean age +/- SD = 15.4 +/- 1.5 years); 17 eumenorrheics and 11 amenorrheics. The participants' body composition was measured pre- and postseason using dual-energy X-ray Absorptiometer (DXA). The eumenorrheics' postseason BMD was significantly greater than the amenorrheics' postseason BMD (F(1,54) = 16.22, p < .05, partial eta2 = .231). The eumenorrheics' postseason bodyweight (F(1,54) = 7.65, p < .05, partial eta2 = .124), BF (F(1,54) = 8.56, p < .05, partial eta2 = .137), and BMC (F(1,54) = 8.52, p < .05, partial eta2 = .136) were significantly greater than the amenorrheic subgroup. There was also a significant seasonal increase in BMD (t(27) = -4.01, p < .05) for the overall group and the eumenorrheic subgroup (t(16) = -3.90, p < .05). Bodyweight best predicted BMD (F(1,26) = 46.434, p < .05, R2 = .641). In the study, athletic amenorrhea was highly associated with lower levels of BMD in the participants, and cross-country running was highly associated with increased BMD.

SUMMARYThis study demonstrates that Bolivian long distance truck drivers are a high risk population of HIV infection and transmission, supporting other global studies involving truck drivers and their high risk. The aims of this investigation were to estimate the prevalence of high risk behaviors and to identify predictors of condom use in this population.Analysis was completed on survey results from 246 male truckers (aged 18-67). About one in three of the truck drivers (30%) reported having had a sexually transmitted infection sometime in their past. More than half (56%) reported having sex with casual partners. Other risks involved unprotected anal sex. Age and two social cognitive constructs (outcome expectations and perceived social norms) predicted condom use from logistic regression analysis. The authors discuss the need for expanded HIV/sexually transmitted infection prevention programs that incorporate social cognitions.

No abstract

With an increasing concern that teachers develop reflective thinking abilities as part of their teacher training programs, there comes a need to know more about the reflector. This knowledge can guide teacher education programs in providing experiences that will enhance or encourage reflective ability. A Q-technique factor analysis was employed to examine a number of psychological and personal characteristics of prospective teachers in order to provide a description of those who have been classified as reflectors. The results indicate that both psychological and personal characteristics may be useful for describing reflectors and non-reflectors. Implications for teacher education programs are discussed.