Biology subjects

Bailey, D. M.

Publications and source records attributed to Bailey, D. M..

4 recordsLinked to original sources

bioRxiv2025

Conservation relevant fine scale distribution and habitat associations of threatened elasmobranchs in temperate nearshore waters

Elasmobranchs are globally threatened and experiencing ongoing declines. Understanding threatened elasmobranch distribution is critical for developing effective marine conservation strategies. However, our knowledge of fine scale elasmobranch habitat association and distribution in temperate nearshore systems is limited. Here, we examined the presence, relative abundance and habitat association of sharks, skates and rays using benthic baited remote underwater stereo-video systems (SBRUVs). From 772 deployments (682 total hours, 53 minutes average soak time) across three years (2021-2023) and two Scottish sea lochs and adjacent bays, elasmobranchs were detected on 31.2% of deployments (n = 241). Our surveys detected six species of elasmobranchs, representing 17.6% of the resident elasmobranch diversity reported to date in nearshore waters < 200 m depth in UK waters. The species detected include two species listed as globally Vulnerable on the IUCN Red List, spiny dogfish (Squalus acanthias) and porbeagle (Lamna nasus) and one Critically Endangered species, flapper skate (Dipturus intermedius). Critically Endangered flapper skate were detected in 5.2% deployments (n = 40) and were the only species recorded which did not show a relationship between the probability of presence and substratum type. Our findings provide critical data on the fine scale spatial distribution and habitat use of elasmobranchs, informing evidence-based conservation measures and supporting more consistent and targeted policy action for these species in Scotland.

ecology↗

bioRxiv2023

Luminal transport rates through intact endoplasmic reticulum limit the magnitude of localized Ca2+ signals

The endoplasmic reticulum (ER) forms an interconnected network of tubules stretching throughout the cell. Understanding how ER functionality relies on its structural organization is crucial for elucidating cellular vulnerability to ER perturbations, which have been implicated in several neuronal pathologies. One of the key functions of the ER is enabling Ca2+ signalling by storing large quantities of this ion and releasing it into the cytoplasm in a spatiotemporally controlled manner. Through a combination of physical modeling and livecell imaging, we demonstrate that alterations in ER shape significantly impact its ability to support efficient local Ca2+ releases, due to hindered transport of luminal content within the ER. Our model reveals that rapid Ca2+ release necessitates mobile luminal buffer proteins with moderate binding strength, moving through a well-connected network of ER tubules. These findings provide insight into the functional advantages of normal ER architecture, emphasizing its importance as a kinetically efficient intracellular Ca2+ delivery system. Significance StatementThe peripheral endoplasmic reticulum forms a continuous network of tubules extending through the entire cell. One of the key functional roles of the ER is the release of Ca2+ ions into the cytosol to support a broad diversity of intracellular signaling processes. Such release events are enabled by the high Ca2+ storage capacity of the ER. This work demonstrates that mobile Ca2+binding buffer proteins and a well-connected lattice-like architecture of the ER network are optimal to supply local Ca2+ signals and that changes in ER structure can modulate Ca2+ release. By linking transport kinetics to Ca2+ release, we demonstrate a key functional role for the interconnected network architecture of the ER.

cell biology↗

bioRxiv2018

Functional implications of impaired dynamic cerebral autoregulation in young healthy women; a comparative investigation

Women exhibit higher prevalence of orthostatic hypotension with presyncopal symptoms compared to men. These symptoms could be influenced by an attenuated ability of the cerebrovasculature to respond to rapid changes in blood pressure (BP) [dynamic cerebral autoregulation (dCA)]. However, the influence of sex on dCA remains equivocal. We compared dCA in 11 women (25 {+/-} 2 y) and 11 age-matched men (24 {+/-} 1 y) using a multimodal approach including a sit-to-stand maneuver and forced oscillations (5 min of squat-stand performed at 0.05 and 0.10 Hz). The prevalence of initial orthostatic hypotension (IOH; decrease in systolic [≥] 40 mmHg and/or diastolic BP [≥] 20 mmHg) during the first 15 sec of sit-to-stand was determined as a functional outcome. In women, the decrease in mean middle cerebral artery blood velocity (MCAvmean) following the sit-to-stand was greater (-20 {+/-} 8 vs. -11 {+/-} 7 cm sec-1; p=0.018) and the onset of the regulatory change (time lapse between the beginning of the sit-to-stand and the increase in the conductance index (MCAvmean/mean arterial pressure(MAP)) was delayed (p=0.007). Transfer function analysis gain during 0.05 Hz squat-stand was [~]48% higher in women (6.4 {+/-} 1.3 vs. 3.8 {+/-} 2.3 sec; p=0.017). The prevalence of IOH was comparable between groups (4/9 vs. 5/9, p=0.637). These results indicate the cerebrovasculature of healthy women has an attenuated ability to react to large and rapid changes in BP in the face of preserved orthostasis, which could be related to a higher cerebrovascular reserve to face a rapid transient hypotension.\n\nNEWS & NOTEWORTHYThe novel findings of this study are that healthy women have impaired dynamic cerebral autoregulation, although the prevalence of orthostatic intolerance was similar in women and men. These results indicate the cerebrovasculature of healthy women has an attenuated ability to react to large and rapid changes in blood pressure in the face of preserved orthostasis, which could be related to a higher cerebrovascular reserve to face a rapid transient hypotension.

physiology↗

bioRxiv2017

Diminished dynamic cerebral autoregulatory capacity with forced oscillations in mean arterial pressure with elevated cardiorespiratory fitness

The effect that cardiorespiratory fitness has on the dynamic cerebral autoregulatory capacity during changes in mean arterial pressure (MAP) remains equivocal. Using a multiple-metrics approach, challenging MAP across the spectrum of physiological extremes (i.e. spontaneous through forced MAP oscillations), we characterized dynamic cerebral autoregulatory capacity in 19 male endurance athletes and 8 controls via three methods: [1] onset of regulation (i.e., time delay before an increase in middle cerebral artery (MCA) conductance [MCA flow velocity (MCAv)/mean arterial pressure (MAP)] and rate of regulation, after transient hypotension induced by sit-to-stand, and transfer function analysis (TFA) of MAP and MCAv responses during [2] spontaneous and [3] forced oscillations (5-min of squat-stand maneuvers performed at 0.05 and 0.10 Hz). Reductions in MAP and mean MCAv (MCAVmean) during initial orthostatic stress (0-30 s after sit-to-stand) and the prevalence of orthostatic hypotension were also determined. Onset of regulation was delayed after sit-to-stand in athletes (3.1{+/-}1.7 vs. 1.5{+/-}1.0 s; p=0.03), but rate of regulation was not different between groups (0.24{+/-}0.05 vs. 0.21{+/-}0.09 s-1; p=0.82). While both groups had comparable TFA metrics during spontaneous oscillations, athletes had higher TFA gain during 0.10 Hz squat-stand vs. recreational controls (p=0.01). Reductions in MAP (p=0.15) and MCAVmean (p=0.11) during orthostatic stress and the prevalence of initial orthostatic hypotension (p=0.65) were comparable between groups. These results indicate an intact ability of the cerebral vasculature to react to spontaneous oscillations but an attenuated capability to counter rapid and large changes in MAP in individuals with elevated cardiorespiratory fitness.\n\nNew findingsO_ST_ABSWhat is the central question of this study?C_ST_ABSO_LIWhat is the impact of cardiorespiratory fitness on dynamic cerebral autoregulatory capacity?\nC_LI\n\nWhat is the main finding and its importance?O_LIOur results indicate an intact ability of the cerebral vasculature to react to spontaneous oscillations but an attenuated capability to counter rapid and large changes in mean arterial pressure in individuals with elevated cardiorespiratory fitness.\nC_LI

physiology↗