In this article, 3 views of the relation between various forms of phonological awareness (detection of rhyme and alliteration and detection of phonemes) and children's reading were tested. These are (a) that the experience of learning to read leads to phoneme awareness and that neither of these is connected to awareness of rhyme, (b) that sensitivity to rhyme leads to awareness of phonemes, which in turn affects reading, and (c) that rhyme makes a direct contribution to reading that is independent of the connection between reading and phoneme awareness. The results from a longitudinal study that monitored the phonological awareness and progress in reading and spelling of 65 children from the ages of 4 years 7 months to 6 years 7 months produced strong support for a combination of the 2nd and 3rd models and none at all for the 1 st model. This research was supported by a grant from the Medical Research Council.We are grateful for the help of Terezinha Carraher who read and commented on an earlier version of the article. We would like to thank the teachers and staff of local primary and first schools for letting us visit the children in our project at school.
Methylglyoxal is a toxic electrophile. In Escherichia coli cells, the principal route of methylglyoxal production is from dihydroxyacetone phosphate by the action of methylglyoxal synthase. The toxicity of methylglyoxal is believed to be due to its ability to interact with the nucleophilic centres of macromolecules such as DNA. Bacteria possess an array of detoxification pathways for methylglyoxal. In E. coli, glutathione-based detoxification is central to survival of exposure to methylglyoxal. The glutathione-dependent glyoxalase I-II pathway is the primary route of methylglyoxal detoxification, and the glutathione conjugates formed can activate the KefB and KefC potassium channels. The activation of these channels leads to a lowering of the intracellular pH of the bacterial cell, which protects against the toxic effects of electrophiles. In addition to the KefB and KefC systems, E. coli cells are equipped with a number of independent protective mechanisms whose purpose appears to be directed at ensuring the integrity of the DNA. A model of how these protective mechanisms function will be presented. The production of methylglyoxal by cells is a paradox that can be resolved by assigning an important role in adaptation to conditions of nutrient imbalance. Analysis of a methylglyoxal synthase-deficient mutant provides evidence that methylglyoxal production is required to allow growth under certain environmental conditions. The production of methylglyoxal may represent a high-risk strategy that facilitates adaptation, but which on failure leads to cell death. New strategies for antibacterial therapy may be based on undermining the detoxification and defence mechanisms coupled with deregulation of methylglyoxal synthesis.
Nursery rhymes are an almost universal part of young English-speaking children's lives. We have already established that there are strong links between children's early knowledge of nursery rhymes at 3;3 and their developing phonological skills over the next year and a quarter. Since such skills are known to be related to children's success in learning to read, this result suggests the hypothesis that acquaintance with nursery rhymes might also affect children's reading. We now report longitudinal data from a group of 64 children from the age of 3;4 to 6;3 which support this hypothesis. There is a strong relation between early knowledge of nursery rhymes and success in reading and spelling over the next three years even after differences in social background, I.Q and the children's phonological skills at the start of the project are taken into account. This raises the question of how nursery rhymes have such an effect. Our answer is that knowledge of nursery rhymes enhances children's phonological sensitivity which in turn helps them to learn to read. This paper presents further analyses which support the idea of this path from nursery rhymes to reading. Nursery rhymes are related to the child's subsequent sensitivity to rhyme and phonemes. Moreover the connection between knowledge of nursery rhymes and reading and spelling ability disappears when controls are made for differences in these subsequent phonological skills.
There has been a growth in students with dyslexia attending university. These students commonly rate writing as one of their greatest problem areas. Our research set out to describe the effects of dyslexia on the writing skills of students compared to age-matched peers and a spelling-skill-matched group. Generally, the texts of the students with dyslexia were poorer than age controls but not poorer than the spelling-skill controls. However, there were no major differences in "higher order" skills such as ideas and organization with the chronological age controls, only in "lower order" transcription skills such as spelling and handwriting fluency. The students with dyslexia made more spelling errors in their essays than one would predict given their dictated spelling skills.
SummaryThe glyoxalase I gene (gloA) of Escherichia coli has been cloned and used to create a null mutant. Cells overexpressing glyoxalase I exhibit enhanced tolerance of methylglyoxal (MG) and exhibit elevated rates of detoxification, although the increase is not stoichiometric with the change in enzyme activity. Potassium efflux via KefB is also enhanced in the overexpressing strain. Analysis of the physiology of the mutant has revealed that growth and viability are quite normal, unless the cell is challenged with MG either added exogenously or synthesized by the cells. The mutant strain has a low rate of detoxification of MG, and cells rapidly lose viability when exposed to this electrophile. Activation of KefB and KefC is diminished in the absence of functional glyoxalase I. These data suggest that the glutathione-dependent glyoxalase I is the dominant detoxification pathway for MG in E. coli and that the product of glyoxalase I activity, S-lactoylglutathione, is the activator of KefB and KefC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations鈥揷itations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright 漏 2024 scite LLC. All rights reserved.
Made with 馃挋 for researchers
Part of the Research Solutions Family.