Callus induction and RAPD analysis of Simarouba glauca DC

Callus induction for somatic embryogenesis from Simarouba glauca DC leaf explants of three genotypes (S. glauca 5, S. glauca 19 and S. glauca 21) was studied. Leaf explants (leaf segments from basal, middle and tip of the leaves) were cultured on two types of nutrient media; SGC1 and SGC2. Both media contained Murashige and Skoog (MS) medium with vitamins: 100 mg/L ascorbic acid, 0.5 mg/L 6-benzylaminopurine (BAP), 0.5 to 5.0 mg/L NAA (1-napthaleneacetic acid), and 3.0 g/L sucrose. The SGC2 media additionally contained 0.5 to 5.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D). SGC2 media generated better callusing response compared to SGC1, thus displaying the importance of using 2,4-D in combination with NAA for callus induction. MS medium containing 2.5 mg/L NAA (SGC1.5) was noted to be the most effective in the initiation of friable embryogenic callus. On the other hand, MS medium containing a combination of 2.0 mg/L NAA and 2.0 mg/L 2,4-D was effective in the early initiation of friable embryogenic callus. In addition, a higher frequency of callus formation was observed from basal leaf segment as compared to that from middle and apical leaf segments. A random amplified polymorphic DNA (RAPD) analysis was also performed to see the genetic differences between the three S. glauca genotypes used in this study. The performance of S. glauca 5 and S. glauca 19 for higher callus frequency over the S. glauca 21 could be attributed to the genotypic differences between these genotypes. Overall, our protocol using SGC 2.4 media yielded optimal results and is suitable for large scale micropropagation of S. glauca. Keywords: Simarouba glauca, somatic embryogenesis, callus, plant growth regulators, RAPD and biofuel.African Journal of Biotechnology, Vol 13(53) 4766-477

An Examination of Psychopathology and Daily Impairment in Adolescents with Social Anxiety Disorder

Although social anxiety disorder (SAD) is most often diagnosed during adolescence, few investigations have examined the clinical presentation and daily functional impairment of this disorder exclusively in adolescents. Prior studies have demonstrated that some clinical features of SAD in adolescents are unique relative to younger children with the condition. Furthermore, quality of sleep, a robust predictor of anxiety problems and daily stress, has not been examined in socially anxious adolescents. In this investigation, social behavior and sleep were closely examined in adolescents with SAD (n = 16) and normal control adolescents (NC; n = 14). Participants completed a self-report measure and an actigraphy assessment of sleep. Social functioning was assessed via a brief speech and a social interaction task, during which heart rate and skin conductance were measured. Additionally, participants completed a daily social activity journal for 1 week. No differences were observed in objective or subjective quality of sleep. Adolescents with SAD reported greater distress during the analogue social tasks relative to NC adolescents. During the speech task, adolescents with SAD exhibited a trend toward greater speech latency and spoke significantly less than NC adolescents. Additionally, SAD participants manifested greater skin conductance during the speech task. During the social interaction, adolescents with SAD required significantly more confederate prompts to stimulate interaction. Finally, adolescents with SAD reported more frequent anxiety-provoking situations in their daily lives, including answering questions in class, assertive communication, and interacting with a group. The findings suggest that, although adolescents with SAD may not exhibit daily impaired sleep, the group does experience specific behavioral and physiological difficulties in social contexts regularly. Social skills training may be a critical component in therapeutic approaches for this group