A Longitudinal Analysis of Stress in African American Youth: Predictors and Outcomes of Stress Trajectories

Few researchers have studied trajectories of stress over time in relation to psychosocial outcomes and behaviors among adolescents. A sample of African American adolescents were assessed longitudinally on perceived stress, psychological well-being, support, antisocial behaviors, and academic success. Patterns of stress over 4 time points were developed using a cluster-analytic approach. Differences among the trajectory clusters were examined using psychosocial outcomes and behaviors. Adolescents with chronic levels of stress reported more anxiety and depression, engaged in antisocial behaviors, and reported less active coping than youth in other trajectories. Adolescents with low levels of stress over time reported fewer psychological problems, perceived more social support, and were more likely to graduate from high school than those with higher stress levels over time. We also found that an increase in stress coincided with a lack of support and more psychological problems over time.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45295/1/10964_2004_Article_465298.pd

Encapsulation of DNA and non-viral protein changes the structure of murine polyomavirus virus-like particles

Asymmetrical-flow field flow fractionation with multiple-angle light scattering (AFFFF-MALS) was, for the first time, used to characterize the size of murine polyomavirus virus-like particles (MPV VLPs) packaged with either insect cell genomic DNA or non-viral protein. Encapsidation of both genomic DNA and non-viral protein were found to cause a contraction in VLP radii of gyration by approximately 1 nm. Non-viral protein packaged into VLPs consisted of a series of glutathione-S-transferase, His and S tags attached to the N-terminal end of the MPV structural protein VP2 (M (r) = 67108). Transmission electron microscopy analysis of MPV VLPs packaging non-viral protein suggested that VLPs grew in diameter by approximately 5 nm, highlighting the differences between this invasive technique and the relatively non-invasive AFFFF-MALS technique. Encapsulation of non-viral protein into MPV VLPs was found to prevent co-encapsidation of genomic DNA. Further investigation into why this occurred led to the discovery that encapsulation of non-viral protein alters the nuclear localization of MPV VLPs during in vivo assembly. VLPs were relocated away from the ring zone and the nuclear membrane towards the centre of the nucleus amongst the virogenic stroma. The change in nuclear localization away from the site where VLP assembly usually occurs is a likely reason why encapsidation of genomic DNA did not take place