Molecular analysis of transgenic rice.
Explore the source record for details and available documents.
Blotting, Southern↗
Biomedical subjects
J P Connell
Publications and source records attributed to J P Connell.
Individual differences and the development of perceived control.
Research on individual differences demonstrates that children's perceived control exerts a strong effect on their academic achievement and that, in turn, children's actual school performance influences their sense of control. At the same time, developmental research shows systematic age-graded changes in the processes that children use to regulate and interpret control experiences. Drawing on both these perspectives, the current study examines (1) age differences in the operation of beliefs-performance cycles and (2) the effects of these cycles on the development of children's perceived control and classroom engagement from the third to the seventh grade. Longitudinal data on about 1,600 children were collected six times (every fall and spring) over 3 consecutive school years, including children's reports of their perceived control and individual interactions with teachers; teachers' reports of each student's engagement in class; and, for a subset of students, grades and achievement tests. Analyses of individual differences and individual growth curves (estimated using hierarchical linear modeling procedures) were consistent, not only with a cyclic model of context, self, action, and outcomes, but also with predictors of individual development over 5 years from grade 3 to grade 7. Children who experienced teachers as warm and contingent were more likely to develop optimal profiles of control; these beliefs supported more active engagement in the classroom, resulting in better academic performance; success in turn predicted the maintenance of optimistic beliefs about the effectiveness of effort. In contrast, children who experienced teachers as unsupportive were more likely to develop beliefs that emphasized external causes; these profiles of control predicted escalating classroom disaffection and lower scholastic achievement; in turn, these poor performances led children to increasingly doubt their own capacities and to believe even more strongly in the power of luck and unknown causes. Systematic age differences in analyses suggested that the aspects of control around which these cycles are organized change with development. The beliefs that regulated engagement shifted from effort to ability and from beliefs about the causes of school performance (strategy beliefs) to beliefs about the self's capacities. The feedback loop from individual performance to subsequent perceived control also became more pronounced and more focused on ability. These relatively linear developmental changes may have contributed to an abrupt decline in children's classroom engagement as they negotiated the transition to middle school and experienced losses in teacher support. Implications are discussed for future study of individual differences and development, especially the role of changing school contexts, mechanisms of influence, and developmentally appropriate interventions to optimize children's perceived control and engagement.
Achievement↗
Emotion regulation in two-year-olds: strategies and emotional expression in four contexts.
A descriptive study of the modulation of negative emotion in the toddler period was conducted by examining expressions of negative emotion and the strategies used to reduce or change these expressions. 6 strategies were identified and evaluated in terms of their frequency of use in different situations, relations with emotional expressiveness, and cross-situational consistency. 37 2-year-olds were seen in 2 laboratory contexts (delay and separation) each with 2 variants. Emotion regulation strategies and emotional expressiveness were coded from videotapes of children's behavior in these 4 situations. Findings suggest that active engagement was most commonly used and most negatively associated with child distress. Use of strategies varied by context, and there was more cross-situational consistency in use of strategies that were more negatively or positively associated with distress within a given context than in use of particular strategies without consideration of their within-context significance.
Child Behavior↗
Educational risk and resilience in African-American youth: context, self, action, and outcomes in school.
This study examined the empirical validity of a model of human motivation as it applies to school success and failure in 3 independent samples of 10- to 16-year-old African-American youth. Specifically, we assessed how indicators of context, self, and action relate to measures of risk and resilient outcomes in school in 3 different samples, using 3 different measurement strategies. Correlational and path analyses on the 3 data sets supported the empirical validity of the model. African-American youth's experience of their parents' school involvement predicted a composite of self-system processes, which in turn predicted the subjects' reports of their engagement in school. Engagement then predicted school performance and adjustment. The data supported a reciprocal path from action to context, suggesting that youth who show more disaffected patterns of behavior and emotion in school experience less support from their families than those reporting more engaged patterns of action. Implications for program and policy decisions are discussed.
Black or African American↗
What motivates children's behavior and emotion? Joint effects of perceived control and autonomy in the academic domain.
This study examined the contribution of perceived control and autonomy to children's self-reported behavior and emotion in the classroom (N = 246 children ages 8-10 years). Multiple regression analyses revealed unique effects of autonomy over and above the strong effects of perceived control. In addition, both sets of perceptions (and their interaction) were found to distinguish children who were active but emotionally disaffected from those who were active and emotionally positive. Specific predictions were also tested regarding the effects of (a) control attributions to 5 causes and (b) 4 reasons for task involvement that differed in degree of autonomy on children's active (vs. passive) behavior and 4 kinds of emotions: boredom, distress, anger, and positive emotions. Implications of the findings for theories of children's motivation are discussed, as well as for diagnostic strategies to identify children at risk for motivational problems
Achievement↗
Requirement for ICR-like sequences in the replication of brome mosaic virus genomic RNA.
Previous studies using a brome mosaic virus (BMV) RNA-2 deletion mutant (pRNA-2 M/S) and additional derivatives as reporters established that viral sequences resembling internal control regions (ICRs) 1 and 2 of tRNA gene promoters are vital to (+)-strand replication in protoplasts. Transfer of these mutations to genomic RNA-2 and functional analysis in protoplast, local lesion, and systemic infections revealed a sequence-specific requirement for bases within the ICR2-like motif. Despite the low (generally less than 20% of wild-type) and sometimes undetectable levels of replication of these RNA-2 mutants, sufficient p2a protein was produced to support at least modest levels of RNA-1, -3 and -4 replication in protoplasts. However, only those RNA-2 ICR2 mutants supporting substantial replication of the viral genome in protoplasts were capable of establishing local lesions in Chenopodium hybridum and systemic infections in barley, further establishing the essential role of the ICR-like sequences in viral infectivity. Upon passage through a second set of barley plants, accumulation patterns for progeny from inocula containing certain RNA-2 mutants paralleled those from wild-type inocula, indicating repair of the introduced mutations. RNA stability and translatability were shown to be unaffected by the introduced mutations. BMV RNA-3 contains several ICR-like sequences, each of which was individually deleted. Whereas deletion of the 5'-terminal ICR2-like motif had little effect on RNA-3 accumulation in protoplasts or local lesion formation, it debilitated systemic spread in barley. Deletion of an internal ICR2-like motif at position 1100 decreased (+):(-) strand asymmetry from greater than 100:1 to 14:1, reduced RNA-3 replication in protoplasts to less than 15% of wild-type, and abolished local lesion and systemic infectivity.
Base Sequence↗
Regulation of (+):(-)-strand asymmetry in replication of brome mosaic virus RNA.
Transfection of barley protoplasts with brome mosaic virus (BMV) RNAs 1 + 2 in the absence of RNA-3 yielded a molar ratio for (+):(-)-strand progeny at 24 hr postinoculation near unity, whereas over 100-fold more (+)- than (-)-strand progeny accumulated in its presence. The presence of RNA-3 enhanced total (+)-strand RNA production 205-fold and that of RNAs 1 + 2 by 29-fold. In contrast, total (-)-strand RNA accumulation decreased by 68% and that for (-)RNAs 1 + 2 by 79% in the presence of RNA-3. Transfections containing an RNA-3 mutant (Gsgi----U RNA-3) that is incapable of yielding RNA-4 as a result of a single nucleotide substitution at the subgenomic RNA initiation site yielded only 66% of the (+):(-) asymmetry seen in the presence of wild-type RNA-3. Only 1.8-fold excess of (+)-over (-)-strand production was obtained for transfections that included delta SGP RNA-3, a deletion that includes the subgenomic promoter core and extends 43 nt into the RNA-4 sequence. Transfections containing RNA-3 mutants bearing frameshifts or deletions in the coat protein cistron yielded levels of asymmetry similar to those seen for Gsgi----U RNA-3. These findings implicate the subgenomic promoter and other sequences in the intercistronic region of RNA-3 as the primary determinants of asymmetric replication, although the coat protein may be an additional factor enhancing the accumulation of (+)-strand RNA.
Capsid↗
Non-replicating deletion mutants of brome mosaic virus RNA-2 interfere with viral replication.
Naturally occurring defective interfering RNAs (DI-RNAs) and satellite RNAs greatly reduce the accumulation of their helper virus in vivo, but often modulate symptom expression in an unpredictable manner. Deletion mutants Nc/S, Na/M and Sa/Nc + M/S, derived from brome mosaic virus (BMV) RNA-2, failed to replicate when co-inoculated with BMV RNAs-1 and -2 to barley protoplasts. However, the inoculum RNA corresponding to these deletion mutants was extremely stable and could have been mistaken for plus-strand progeny had minus-strand progeny analysis been omitted. These results accentuate the need for such tests in evaluating the ability of mutant viral sequences to replicate. One of the mutants, Nc/S, effectively interfered with the accumulation of BMV RNAs-1 and -2 in barley protoplasts. This non-replicating interfering RNA was termed NRI RNA-2 Nc/S. When present with RNAs-1 and -2 at low inoculum amounts (1 microgram), NRI RNA-2 Nc/S reduced replication of RNA-2, the parental RNA, by 63% and preferentially interfered with minus-strand RNA accumulation. At higher levels (4 micrograms), it completely displaced replication of both RNAs-1 and -2. Mutations eliminating translation of a truncated p2a protein from NRI RNA-2 Nc/S did not alleviate the interference effect, demonstrating that a defective replicase protein was not responsible for the decreased accumulation of genomic RNA. At an NRI RNA: genomic RNA inoculum molar ratio of 1:1, NRI RNA-2 Nc/S reduced the accumulation of all helper virus RNAs by 55%. Since this reduction was seen for both wild-type RNA-3 and delta SGP RNA-3, a deletion mutant of RNA-3 that lacks the subgenomic promoter necessary for coat protein expression, it was evident that the effective interference mediated by NRI RNA-2 Nc/S was not mitigated by encapsidation. The ability of the NRI RNAs to mimic satellite DI RNAs in depressing helper virus replication suggests that their expression in transgenic plants may provide a new and widely applicable approach for inducing resistance to viral infection.
Blotting, Northern↗
Artificial defective interfering RNAs derived from brome mosaic virus.
Naturally occurring defective interfering RNAs (DI-RNAs) greatly reduce the accumulation of their helper virus in vivo, but are rarely associated with plant positive-strand RNA viruses. Deletion mutants pRNA-2 M/S and pRNA-2 E/S, derived from brome mosaic virus (BMV) genomic RNA-2, replicated in a manner dependent on BMV RNA-1 and -2, and effectively interfered with their accumulation in barley protoplasts. Based on their mode of replication, these mutant RNAs have been termed parasitic RNAs (pRNAs). When present with RNA-1 and -2 at low inoculum amounts, pRNA-2 M/S and pRNA-2 E/S reduced the level of replication of RNA-2, the parental RNA, by 37% and 64%, respectively. Greater amounts of pRNA in the inoculum completely eliminated the replication of both RNA-1 and -2. Mutations that prevented translation of truncated proteins from the pRNAs did not affect interference, but those that reduced pRNA replication decreased their ability to interfere with genomic RNA replication. At a molar pRNA: genomic RNA inoculum ratio of 1.5:1, pRNA-2 E/S reduced the accumulation of all helper virus RNAs by greater than 60%. This occurred in the presence of wild-type RNA-3 or delta SGP RNA-3, a deletion mutant of RNA-3 that lacks the subgenomic promoter necessary for coat protein expression, demonstrating that the interference mediated by the pRNAs was not effected by encapsidation. These data indicate that the expression of pRNAs that function as artificial DI-RNAs in transgenic plants may be an approach for inducing resistance to virus infection which is applicable to a wide range of plant viruses.
Blotting, Northern↗
Perceived locus of causality and internalization: examining reasons for acting in two domains.
Theories of internalization typically suggest that self-perceptions of the "causes" of (i.e. reasons for) behavior are differentiated along a continuum of autonomy that contains identifiable gradations. A model of perceived locus of causality (PLOC) is developed, using children's self-reported reasons for acting. In Project 1, external, introjected, identified, and intrinsic types of reasons for achievement-related behaviors are shown to conform to a simplex-like (ordered correlation) structure in four samples. These reason categories are then related to existing measures of PLOC and to motivation. A second project examines 3 reason categories (external, introject, and identification) within the domain of prosocial behavior. Relations with measures of empathy, moral judgement and positive interpersonal relatedness are presented. Finally, the proposed model and conceptualization of PLOC are discussed with regard to intrapersonal versus interpersonal perception, internalization, cause-reason distinctions, and the significance of perceived autonomy in human behavior.
Achievement↗
Gender and sex-role influences on children's self-esteem.
This study examined direct and moderating influences of gender and sex-role orientations on children's general self-esteem. Moderating influences of these variables on the prediction of self-esteem were examined with respect to two sets of competence beliefs regarding school achievement: perceived capacities and perceived strategies for doing well in school. One hundred nineteen fourth-, fifth-, and sixth-grade children were assessed using the Perceived Competence Scale for Children (Harter, 1982), the Multidimensional Measure of Children's Perceptions of Control (Connell, 1985), and the Children's Personal Attributes Questionnaire (Hall & Halberstadt, 1980). Correlational and hierarchical multiple regression analyses indicated that upper elementary schoolchildren's general self-esteem is (a) marginally related to biological gender, with boys showing a slight advantage; (b) significantly related to masculinity and androgyny; and (c) predicted more strongly by perceived capacities to do schoolwork in girls than in boys, and by perceived (lack of) strategies for academic success in nontraditionally sex-typed children than in traditionally sex-typed children. Of the two nontraditionally sex-typed groups, androgynous children were found to have more positive school competence beliefs than were undifferentiated children.
Achievement↗
Comparison of methods for enumeration of selected coliforms exposed to ozone.
mT7 medium performed no better than m-Endo medium in enumerating cells of Escherichia coli and Citrobacter freundii exposed to ozone. Also, there was no difference in the plate count of heterotrophic bacteria in ozonated raw water determined on modified Henrici agar or R2A agar. Statistically significant differences were seen between bacteria and the type of water in which they were suspended during ozonation.
Citrobacter↗
Temperament, emotion, and social interactive behavior in the strange situation: a component process analysis of attachment system functioning.
This study examines the contributions of temperamentally and nontemperamentally based emotional reactions to the organization of social interactive behavior within the Strange Situation to better understand the emotional underpinnings of attachment system functioning. At 12 1/2 and 19 1/2 months, temperamental fear (assessed via maternal report) was related to independent per-episode dimensions of social interactive and distress behavior. Fear was moderately correlated with both distress and interactive dimensions at each age. Path-analytic models revealed that temperamental fear had direct effects on interactive behavior and also indirect effects mediated by preceding distress reactions. However, residualized measures of "context-specific" distress (with temperamental variance removed) were still highly consistent across Strange Situation episodes and also significantly predicted subsequent social interactive behavior; furthermore, stable distress reactions from 12 1/2 to 19 1/2 months significantly predicted concurrent stability in social interactive behavior. We discuss likely sources of "context-specific" emotional influences on Strange Situation behavior and also age-related differences in these findings.
Affective Symptoms↗
Self-system concomitants of discrepancies between children's and teacher's evaluations of academic competence.
The purpose of this study was to elucidate the psychological concomitants of discrepancies between fourth- to sixth-grade children's perceptions of academic competence and 2 measures of their "actual" competence in this domain: teacher ratings and achievement test scores. Over-, under-, and congruent child raters were identified on the basis of the 2 external standards and then compared on child and teacher ratings of self-esteem, self-regulatory style, and coping with perceived failure. 6 teachers and 121 lower- to upper-middle-class suburban students participated. As predicted, no differences were obtained between congruent and distorted (combined over- and under-) raters on these self-system variables. Consistent with previous research, overrating children showed higher self-esteem on self- and teacher ratings than underraters. After controlling for level of perceived competence, overraters scored higher on anxiety, and, when overrating occurred against the teacher standard, these children were rated by teachers as having lower self-esteem, poorer coping strategies, and less internalized self-regulatory styles. Comparing the 2 standards, self-reported difficulties were associated with underrating against the teacher's standard but not the achievement standard. Teacher reported difficulties were associated with the opposite pattern of underrating against the 2 standards. Motivational factors contributing to patterns of discrepancies are discussed, as are the educational implications of mismatches between teacher and student perceptions of objective and intrapsychic aspects of school experience.
Achievement↗
Pea chloroplast glutathione reductase: purification and characterization.
Glutathione reductase (EC 1.6.4.2) was purified from intact pea (Pisum sativum) chloroplasts by a method which includes affinity chromatography on ADP-agarose. Fractions from the affinity column which had glutathione reductase activity consisted of polypeptides of 60 and 32 kilodaltons. Separation of the proteins by electrophoresis on native gels showed that glutathione reductase activity was associated with 60 kilodalton polypeptides and not with the 32 kilodalton polypeptides. Antibodies to spinach whole leaf glutathione reductase (60 kilodaltons) cross-react with the chloroplast 60 kilodalton glutathione reductase but not the 32 kilodalton polypeptides. In the absence of dithiothreitol the 60 kilodalton polypeptides showed a shift in apparent molecular weight on sodium dodecyl sulfate gels to 72 kilodaltons. Dithiothreitol did not alter the activity of the chloroplast enzyme. Chloroplast glutathione reductase is relatively insensitive to NADPH.
Journal Article↗
A new multidimensional measure of children's perceptions of control.
Perceived control plays a central role in many motivational and cognitive accounts of behavior. In this study, a new 48-item self-report instrument, the Multidimensional Measure of Children's Perceptions of Control, is described. Perceptions of control are defined as children's understanding of the locus of the sufficient cause for success and failure outcomes. 3 dimensions of third- through ninth-grade children's perceptions of control are independently assessed: internal, powerful others, and unknown. Each of these sources of control is assessed within 3 behavioral domains: cognitive, social, and physical. General items are also included. Perceptions of control over success outcomes and failure outcomes are assessed separately. The psychometric properties of the new measure's subscales are presented. Correlations of the new measure with measures of perceived and actual competence and findings demonstrating the sensitivity of the new measure to developmental, gender, and environmental influences are reported. It is argued that the new measure is an advance over existing measures of internal versus external locus of control in children because it provides domain-specific assessments of 3 separate dimensions of locus of control, including the previously untapped dimension of unknown control.
Achievement↗