Utilising a 1,8-naphthalimide probe for the ratiometric fluorescent visualisation of caspase-3

The development of selective and sensitive probes for monitoring caspase-3 activity–a critical enzyme involved in apoptosis–remains an area of significant interest in biomedical research. Herein, we report the synthesis and characterisation of a novel ratiometric fluorescent probe, Ac-DEVD-PABC-Naph, designed to detect caspase-3 activity. The probe utilises a 1,8-naphthalimide fluorophore covalently linked to a peptide sequence via a self-immolative p-aminobenzyl alcohol (PABA) linker. Upon enzymatic cleavage by caspase-3, the probe undergoes spontaneous degradation, releasing the free naphthalimide fluorophore, resulting in a ratiometric change in fluorescence emission. Spectroscopic studies revealed a time-dependent ratiometric fluorescent response, demonstrating the probe’s ability to visualise caspase-3 activity with high sensitivity. Enzyme kinetics such as Km (Michaelis constant), kcat (turnover number), and LOD (Limit of Detection) were obtained, suggesting that the probe possesses comparable kinetic data to other probes in literature, but with the added benefits of ratiometric detection. Selectivity studies also demonstrated the probe’s specificity for caspase-3 over other endogenous species and enzymes. Ac-DEVD-PABC-Naph may be a promising tool for the quantitative detection and fluorescent visualisation of caspase-3 activity in biological systems, with potential applications in apoptosis research and drug development

Exploring the role of normative, financial and environmental information in promoting uptake of energy efficient technologies

The potential of normative and feedback (financial vs. environmental) information in guiding pro-environmental decision-making behaviour was explored in a 2 × 2 (plus control) choice experiment. Using the context of home heating, 599 non-student participants from the UK general public were asked to choose between a standard heating system (a gas boiler) and a relatively more-energy efficient option (a heat pump). In line with evidence for the energy efficiency gap for sustainable innovations, there was low uptake of the heat pump (32.5%) in the control condition where no frame information was provided. Yet, in both conditions where normative information was provided, respondents were significantly more likely (vs. control) to choose the heat pump (financial + norm OR 3.63; 95% CIs 2.13,6.19; environmental + norm OR 3.09; 95% CIs 1.67,4.79), advancing understanding of normative social influence in the context of pro-environmental purchase behaviour. When normative information was not provided, only financial (OR 2.82; 95% CIs 1.67,4.79) but not environmental (OR 1.33; 95% CIs 0.78,2.26), feedback was associated with a significantly greater likelihood of heat pump choice. The main effect of normative information was replicated for behavioural intentions (though only for homeowners), but there was no norm-feedback interaction (regardless of homeownership). The implications for researchers looking to promote ‘green’ choice in the context of new technology adoption are discussed.</p

The Effects of Prenatal Protein Restriction on β-Adrenergic Signalling of the Adult Rat Heart during Ischaemia Reperfusion

A maternal low-protein diet (MLP) fed during pregnancy leads to hypertension in adult rat offspring. Hypertension is a major risk factor for ischaemic heart disease. This study examined the capacity of hearts from MLP-exposed offspring to recover from myocardial ischaemia-reperfusion (IR) and related this to cardiac expression of β-adrenergic receptors (β-AR) and their associated G proteins. Pregnant rats were fed control (CON) or MLP diets (n = 12 each group) throughout pregnancy. When aged 6 months, hearts from offspring underwent Langendorff cannulation to assess contractile function during baseline perfusion, 30 min ischemia and 60 min reperfusion. CON male hearts demonstrated impaired recovery in left ventricular pressure (LVP) and dP/dtmax (P < 0.01) during reperfusion when compared to MLP male hearts. Maternal diet had no effect on female hearts to recover from IR. MLP males exhibited greater membrane expression of β2-AR following reperfusion and urinary excretion of noradrenaline and dopamine was lower in MLP and CON female rats versus CON males. In conclusion, the improved cardiac recovery in MLP male offspring following IR was attributed to greater membrane expression of β2-AR and reduced noradrenaline and dopamine levels. In contrast, females exhibiting both decreased membrane expression of β2-AR and catecholamine levels were protected from IR injury