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Maternal Control (maternal + control)
Selected AbstractsMaternal control of cold and desiccation tolerance in eggs of the band-legged ground cricket Dianemobius nigrofasciatus in relation to embryonic diapauseENTOMOLOGICAL RESEARCH, Issue 1 2008Shin G. GOTO Abstract Cold and desiccation tolerance was investigated in the eggs of the band-legged ground cricket Dianemobius nigrofasciatus in relation to embryonic diapause. Diapause eggs were more tolerant to both desiccation and cold than non-diapause eggs. In addition, diapause-destined eggs on day zero (0,12 h after being laid) already showed high tolerance to these stresses before entering diapause. This clearly indicates that stress tolerance, like diapause, is controlled by photoperiod, but is not directly associated with diapause itself. Because the acquisition of stress tolerance predates the onset of diapause, it is plausible that diapause programming during some period before the onset of diapause is involved in the acquisition of stress tolerance. Weights and sizes were nearly identical in short-day and long-day eggs until day five. Sorbitol, a major sugar alcohol in eggs of D. nigrofasciatus, was accumulated at the same level in short-day and long-day eggs on days zero and five. These results indicate that the surface-to-volume ratio as well as the accumulation of sugar alcohol is not involved in the acquisition of stress tolerance. Maternal factors are clearly involved in the acquisition of stress tolerance in D. nigrofasciatus eggs, but the physiological mechanisms underlying the tolerance are still unclear. [source] Focused attention in toddlers: measurement, stability, and relations to negative emotion and parentingINFANT AND CHILD DEVELOPMENT, Issue 4 2008Bridget M. Gaertner Abstract This longitudinal study examined individual differences and correlates of focused attention when toddlers were approximately 18 months old (T1; n=256) and a year later (T2; n=230). Toddlers' attention and negative emotionality were reported by mothers and non-parental caregivers and rated globally by observers. Toddlers' focused attention also was observed during two mother,child interactions and an independent play task. Measures of maternal emotional support and control were obtained via self-report and observation. Some contemporaneous relations among indices of toddlers' attention were obtained, particularly for observed measures. Moreover, all measures of attention demonstrated stability across time. Negative emotionality was negatively related to toddlers' observed attention at both ages, whereas maternal praise had positive concurrent associations. Maternal control was negatively related to observed attention at T2 and also predicted longitudinally, but only for children who initially had low or moderate attention. The findings suggest that individual differences in focused attention evidence stability early in life but can be influenced by adult socialization. Copyright © 2008 John Wiley & Sons, Ltd. [source] Do maternal parenting practices predict problematic patterns of adolescent alcohol consumption?ADDICTION, Issue 5 2010Rosa Alati ABSTRACT Objective This study examines whether a mother's style of parenting at child age 5 years predicts problematic patterns of drinking in adolescence, after controlling for relevant individual, maternal and social risk factors. Methods Data were used from the Mater-University Study of Pregnancy, an Australian longitudinal study of mothers and their children from pregnancy to when the children were 14 years of age. Logistic regression analyses examined whether maternal parenting practices at child age 5 predicted problematic drinking patterns in adolescence, after controlling for a range of confounding covariates. Results Physical punishment at child age 5 did not predict adolescent alcohol problems at follow-up. Results indicated that low maternal control at child age 5 predicted adolescent occasional drinking patterns at age 14. More frequent maternal partner change coupled with lower levels of control was the strongest predictor of more problematic patterns of drinking by adolescents. Conclusions These findings highlight the importance of family structure and level of parental control in the development of problematic patterns of drinking in adolescence. [source] Parenting behaviour as a mediator between young children's negative emotionality and their anxiety/depressionINFANT AND CHILD DEVELOPMENT, Issue 4 2010Corine O. van der Bruggen Abstract The goal of this longitudinal study was to examine observed paternal and maternal control (psychological control and autonomy granting) and support (rejection and emotional warmth) as mediators of the relation between children's negative emotionality at 3.5 years of age and depression and anxiety problems at 4.5 years. For 35 children, 60-min unstructured parent,child interactions were rated at 4.5 years. Results indicated that maternal rejection mediated the relation between children's negative emotionality and their later anxiety/depression. Higher levels of child negative emotionality predicted more psychological control in mothers, but did not predict any parenting behaviours in fathers. Higher levels of paternal autonomy granting were associated with more child anxiety/depression. Unexpectedly, however, more maternal emotional warmth was related to higher levels of child anxiety/depression. The findings offer new insights to guide future research on the (mediating) role of parenting behaviours in the relation between children's negative emotionality and their internalizing problems. Copyright © 2010 John Wiley & Sons, Ltd. [source] Inheritance of progeny sex ratio in Urtica dioicaJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2007G. A. GLAWE Abstract Seed samples collected from female Urtica dioica plants in the field showed considerable inter-family variation in the sex ratio (faction of males). To investigate the inheritance pattern of the sex ratio trait, crosses were performed between individual male and female plants from different sex ratio families. Our results suggest, at least for the families studied here, that maternal parents strongly contribute to the variation in the primary sex ratio. Furthermore, progeny sex ratios from reciprocal crosses were significantly different and resembled the sex ratios produced by their maternal parents. We discuss the possible mechanisms underlying maternal control. [source] How many symbionts are provided by mothers, acquired by offspring, and needed for successful vertical transmission in an obligate insect,bacterium mutualism?MOLECULAR ECOLOGY, Issue 24 2007TAKAHIRO HOSOKAWA Abstract Vertical symbiont transmission is among the most pivotal processes for maintenance of symbiotic associations. However, it is poorly understood whether and how the levels of resource allocation and investment upon vertical transmission are regulated. The stinkbug Megacopta punctatissima is obligatorily associated with the gut symbiotic bacterium ,Candidatus Ishikawaella capsulata', whose transmission is mediated by a unique mechanism called ,symbiont capsule'. We investigated the population dynamics of the symbiont during vertical transmission in the host,symbiont mutualism. The stinkbug mothers produced one capsule for around 3.6 eggs irrespective of clutch size, suggesting a strict maternal control over symbiont supply for the offspring. However, experimental manipulation of egg/capsule ratios revealed that one capsule is sufficient for symbiont transmission to six nymphs. Quantitative polymerase chain reaction analyses demonstrated that a capsule contains 1.2 × 108 symbionts, a newborn nymph possesses 2 × 107 symbionts from a capsule, and thus one capsule certainly contains a sufficient amount of symbiont cells for six nymphs. These results indicated that the stinkbug mothers produce 1.7 times more symbiont capsules than needed. The newborn nymphs consistently harboured around 2 × 107 symbionts, also suggesting a nymphal control over symbiont transmission. The threshold symbiont titre minimally needed for successful vertical transmission was estimated to be 1.9 × 106 symbionts, which is only 1/10 of the actual symbiont titre detected in a newborn nymph. These results illuminate several ecological factors that may be relevant to parental and offspring controls over symbiotic resource allocation through host insect generations. [source] Identification and inheritance of a partially dominant gene for yellow seed colour in Brassica napusPLANT BREEDING, Issue 1 2005X. P. Liu Abstract A yellow-seeded doubled haploid (DH) line no. 2127-17, derived from a resynthesized Brassica napus L., was crossed with two black-seeded Brassica cultivars ,Quantum' and ,Sprint' of spring type. The inheritance of seed colour was investigated in the F2, and BC1 populations of the two crosses and also in the DH population derived from the F1 of the cross ,Quantum'× no. 2127-17. Seed colour analysis was performed with the colorimeter CR-300 (Minolta, Japan) together with a visual classification system. The immediate F1 seeds of the reciprocals in the two crosses had the same colour as the self-pollinated seeds of the respective black- and yellow-seeded female parents, indicating the maternal control of seed colour. The F1 plants produced yellow-brown seeds that were darker in colour than the seeds of no. 2127-17, indicating the partial dominance of yellow seed over black. In the segregating BC1 progenies of the two crosses, the frequencies of the black- and yellow-seeded plants fit well with a 1 : 1 ratio. In the cross with ,Quantum', the frequencies of yellow-seeded and black-seeded plants fit with a 13 : 3 ratio in the F2 progeny, and with a 3 : 1 ratio in the DH progeny. However, a 49 : 15 segregation ratio was observed for the yellow-seeded and black-seeded plants in the F2 progeny of the cross with ,Sprint'. It was postulated from these results that seed colour was controlled by three pairs of genes. A dominant yellow-seeded gene (Y) was identified in no. 2127-17 that had epistatic effects on the two independent dominant black-seeded genes (B and C), thereby inhibiting the biosynthesis of seed coat pigments. [source] Maternal cyclin B levels "Chk" the onset of DNA replication checkpoint control in DrosophilaBIOESSAYS, Issue 10 2007Dhananjay Yellajoshyula In many animals, early development of the embryo is characterized by synchronous, biphasic cell divisions. These cell divisions are controlled by maternally inherited proteins and RNAs. A critical question in developmental biology is how the embryo transitions to a later pattern of asynchronous cell divisions and transfers the prior maternal control of development to the zygotic genome. The most-common model regarding how this transition from maternal to zygotic control is regulated posits that this is a consequence of the limitation of maternal gene products, due to their titration during early cell divisions. Here we discuss a recent article by Crest et al.1 that instead proposes that the balance of Cyclin-dependent Kinase 1 and Cyclin B (Cdk1-CycB) activity relative to that of the Drosophila checkpoint kinase Chk1 determines when asynchronous divisions begin. BioEssays 29:949,952, 2007. © 2007 Wiley Periodicals, Inc. [source] Potential mechanisms of avian sex manipulationBIOLOGICAL REVIEWS, Issue 4 2003THOMAS W. PIKE ABSTRACT The aim of this review is to consider the potential mechanisms birds may use to manipulate the sex of their progeny, and the possible role played by maternal hormones. Over the past few years there has been a surge of reports documenting the ability of birds to overcome the rigid process of chromosomal sex determination. However, while many of these studies leave us in little doubt that mechanisms allowing birds to achieve this feat do exist, we are only left with tantalizing suggestions as to what the precise mechanism or mechanisms may be. The quest to elucidate them is made no easier by the fact that a variety of environmental conditions have been invoked in relation to sex manipulation, and there is no reason to assume that any particular mechanism is conserved among the vast diversity of species that can achieve it. In fact, a number of intriguing proposals have been put forward. We begin by briefly reviewing some of the most recent examples of this phenomenon before highlighting some of the more plausible mechanisms, drawing on recent work from a variety of taxa. In birds, females are the heterogametic sex and so non-Mendelian segregation of the sex chromosomes could conceivably be under maternal control. Another suggestion is that follicles that ultimately give rise to males and females grow at different rates. Alternatively, the female might selectively abort embryos or,dump lay'eggs of a particular sex, deny certain ova a chance of ovulation, fertilization or zygote formation, or selectively provision eggs so that there is sex-specific embryonic mortality. The ideas outlined in this review provide good starting points for testing the hypotheses both experimentally (behaviourally and physiologically) and theoretically. [source] | ||||||||||