Project P.A.T.H.S. in Hong Kong: New Curriculum in Response to Adolescent Developmental Issues

2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Effectiveness of the Project P.A.T.H.S. in Hong Kong: Evaluation Based on Different Strategies and Different Studies over Time

2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Topographical and seasonal trends in transpiration by two co-occurring Eucalyptus species during two contrasting years in a low rainfall environment

Understanding the strategies that confer resilience on natural woodlands in drought prone environments is important for the conservation of these and similar ecosystems. Our main aim in this 2-year study was to assess traits (sapwood area, sapwood density and leaf area index) that control transpiration in Eucalyptus camaldulensis and E. microcarpa in a natural forest in which topographical variation created surface soils of sandy clay in a depression (clay-zone) and of loamy sand underlain by a dense profile on the terraces (sand-zone). The clay-zone had a wetter profile due to extra water supply through subsurface lateral flow from the adjoining, topographically higher, sand-zone. In the clay-zone, the differences between the two tree species in their hydraulic attributes were large and rates of water use were widely divergent. Rates of transpiration per unit land area (Ec) and canopy conductance of E. camaldulensis that was dominant in the clay-zone were about 50% lower than those for E. microcarpa in the same zone. This was in marked contrast to the behavior of trees growing in the sand-zone where water availability was persistently low and variations in sapwood density, sapwood area and canopy conductance were narrow. This resulted in almost identical rates of water use for the two species in the sand-zone, despite E. microcarpa dominating the stand. Contrary to many previous studies, sapwood density was positively correlated with Ec in these eucalypt species, while the proportion of trunk area assigned to sapwood declined with sapwood density. Consequently in this low rainfall environment, with prolonged dry seasons, dense sapwood safeguards against turgor loss, and possibly xylem embolism, thereby allowing Ec to be sustained under extremely low soil-water availability. We concluded that variation in hydraulic traits is less likely where trees are under persistent water-stress than where the stress is short and relatively mild. We developed single functions for predicting Ec for the two species by integrating their responses to micrometeorological and soil-water conditions. © 2010

Rapid kinetics of iron responsive element (IRE) RNA/iron regulatory protein 1 and IRE-RNA/eIF4F complexes respond differently to metal ions

Metal ion binding was previously shown to destabilize IRE-RNA/IRP1 equilibria and enhanced IRE-RNA/eIF4F equilibria. In order to understand the relative importance of kinetics and stability, we now report rapid rates of protein/RNA complex assembly and dissociation for two IRE-RNAs with IRP1, and quantitatively different metal ion response kinetics that coincide with the different iron responses in vivo. kon, for FRT IRE-RNA binding to IRP1 was eight times faster than ACO2 IRE-RNA. Mn2+ decreased kon and increased koff for IRP1 binding to both FRT and ACO2 IRE-RNA, with a larger effect for FRT IRE-RNA. In order to further understand IRE-mRNA regulation in terms of kinetics and stability, eIF4F kinetics with FRT IRE-RNA were determined. kon for eIF4F binding to FRT IRE-RNA in the absence of metal ions was 5-times slower than the IRP1 binding to FRT IRE-RNA. Mn2+ increased the association rate for eIF4F binding to FRT IRE-RNA, so that at 50 µM Mn2+ eIF4F bound more than 3-times faster than IRP1. IRP1/IRE-RNA complex has a much shorter life-time than the eIF4F/IRE-RNA complex, which suggests that both rate of assembly and stability of the complexes are important, and that allows this regulatory system to respond rapidly to change in cellular iron

Implications of sperm banking for health-related quality of life up to 1 year after cancer diagnosis.

Sperm banking is recommended for all men diagnosed with cancer where treatment is associated with risk of long-term gonadatoxicity, to offer the opportunity of fatherhood and improved quality of life. However, uptake of sperm banking is lower than expected and little is known about why men refuse. Our aims were to determine: (i) demographic and medical variables associated with decisions about banking and (ii) differences in quality of life between bankers and non-bankers at diagnosis (Time 1 (T1)) and 1 year later (Time 2 (T2))

Pre-cooling for endurance exercise performance in the heat: a systematic review.

PMCID: PMC3568721The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1741-7015/10/166. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Endurance exercise capacity diminishes under hot environmental conditions. Time to exhaustion can be increased by lowering body temperature prior to exercise (pre-cooling). This systematic literature review synthesizes the current findings of the effects of pre-cooling on endurance exercise performance, providing guidance for clinical practice and further research

Candida albicans repetitive elements display epigenetic diversity and plasticity

Transcriptionally silent heterochromatin is associated with repetitive DNA. It is poorly understood whether and how heterochromatin differs between different organisms and whether its structure can be remodelled in response to environmental signals. Here, we address this question by analysing the chromatin state associated with DNA repeats in the human fungal pathogen Candida albicans. Our analyses indicate that, contrary to model systems, each type of repetitive element is assembled into a distinct chromatin state. Classical Sir2-dependent hypoacetylated and hypomethylated chromatin is associated with the rDNA locus while telomeric regions are assembled into a weak heterochromatin that is only mildly hypoacetylated and hypomethylated. Major Repeat Sequences, a class of tandem repeats, are assembled into an intermediate chromatin state bearing features of both euchromatin and heterochromatin. Marker gene silencing assays and genome-wide RNA sequencing reveals that C. albicans heterochromatin represses expression of repeat-associated coding and non-coding RNAs. We find that telomeric heterochromatin is dynamic and remodelled upon an environmental change. Weak heterochromatin is associated with telomeres at 30?°C, while robust heterochromatin is assembled over these regions at 39?°C, a temperature mimicking moderate fever in the host. Thus in C. albicans, differential chromatin states controls gene expression and epigenetic plasticity is linked to adaptation

Abnormal cognition, sleep, EEG and brain metabolism in a novel knock-in Alzheimer mouse, PLB1

Peer reviewedPublisher PD

Regulation of morphological differentiation in S. coelicolor by RNase III (AbsB) cleavage of mRNA encoding the AdpA transcription factor

RNase III family enzymes, which are perhaps the most widely conserved of all ribonucleases, are known primarily for their role in the processing and maturation of small RNAs. The RNase III gene of Streptomyces coelicolor, which was discovered initially as a global regulator of antibiotic production in this developmentally complex bacterial species and named absB (antibiotic biosynthesis gene B), has subsequently also been found to modulate the cellular abundance of multiple messenger RNAs implicated in morphological differentiation. We report here that regulation of differentiation-related mRNAs by the S. coelicolor AbsB/RNase III enzyme occurs largely by ribonucleolytic cleavage of transcripts encoding the pleiotropic transcription factor, AdpA, and that AdpA and AbsB participate in a novel feedback-control loop that reciprocally regulates the cellular levels of both proteins. Our results reveal a previously unsuspected mechanism for global ribonuclease-mediated control of gene expression in streptomycetes

DNA recognition and transcriptional regulation by the WhiA sporulation factor

Sporulation in the filamentous bacteria Streptomyces coelicolor is a tightly regulated process involving aerial hyphae growth, chromosome segregation, septation and spore maturation. Genetic studies have identified numerous genes that regulate sporulation, including WhiA and the sigma factor WhiG. WhiA, which has been postulated to be a transcriptional regulator, contains two regions typically associated with DNA binding: an N-terminal domain similar to LAGLIDADG homing endonucleases, and a C-terminal helix-turn-helix domain. We characterized several in vitro activities displayed by WhiA. It binds at least two sporulation-specific promoters: its own and that of parABp2. DNA binding is primarily driven by its HTH domain, but requires full-length protein for maximum affinity. WhiA transcription is stimulated by WhiG, while the WhiA protein binds directly to WhiG (leading to inhibition of WhiG-dependent transcription). These separate activities, which resemble a possible feedback loop, may help coordinate the closely timed cessation of aerial growth and subsequent spore formation