Biology subjects

Hopkins, T.

Publications and source records attributed to Hopkins, T..

5 recordsLinked to original sources

bioRxiv2026

First record of the subfamily Eucerotinae (Hymenoptera: Ichneumonidae) from the mainland Afrotropics, with a description of a new species

The ichneumonid subfamily Eucerotinae has been thought to be almost absent from the tropics, with the only known Afrotropical species found in Madagascar. We report the subfamily to be present in the mainland Afrotropics, and describe a new species, Euceros species 1 from Uganda and Cameroon (name not yet shown in preprint). The subfamily had likely not been observed in the mainland Afrotropics before due to low abundances and insufficient sampling. More Eucerotinae likely remain to be discovered in tropical Africa and Asia, although tropical America may genuinely have few eucerotine species. Much more extensive sampling will be needed before it is possible to make confident estimates of how eucerotine diversity is distributed globally.

zoology↗

bioRxiv2026

Unravelling the distinct phenotype and mechanosensitive properties of different tendon cell populations.

Tendinopathy arises from maladaptive cellular responses, though the drivers remain unclear. Here we identify and characterise a previously undescribed tendon cell population residing within interfascicular matrix (IFM), demonstrating its importance as the primary mechanosensitive cell in tendon. We describe the first successful isolation and long-term culture of primary IFM and fascicular matrix (FM) cells, enabling direct comparison of their phenotypes and mechanosensitivity. IFM cells exhibited a potent response to stiff substrates, displaying cytoskeletal remodelling, rapid drifting of tenogenic and ECM gene expression, and proliferative decline, while FM cells remained largely unaltered. Crucially, transferring IFM cells to compliant, IFM-like substrates recovered their proliferative capacity, morphology, gene expression. This work defines IFM cells as the primary mechanosensitive tendon cell population, with implications for tendon ageing, injury, and regeneration. Importantly, it also enables identification of cell surface markers to isolate this population from other tendons, opening new avenues to explore mechanobiology-guided tendon therapeutics.

bioengineering↗

bioRxiv2025

Human coronary artery tri-culture organ-chip recapitulates anti-inflammatory effect of pulsatile wall strain

Inflammation is a precursor to vascular diseases, including atherosclerosis, and is modulated by the local biomechanical environment. There is an urgent need for improved in vitro models, to advance understanding, and to test new therapeutic approaches.. This study describes the development and characterization of a human coronary artery organ-chip model of vascular inflammation, with physiological biomechanical stimulation. Human coronary artery endothelial cells and smooth muscle cells were cultured on appropriate extracellular matrices in the two adjoining channels of the Chip-S1(R) from Emulate Inc. Both endothelial and smooth muscle cells demonstrated characteristic phenotypic identity, shown by expression of CD31 and -SMA respectively. Application of physiological pulsatile tensile strain induced alignment of both cell types, perpendicular to strain direction, as seen in vivo. Addition of TNF- to the vascular channel drove an inflammatory response in both cell types, shown by upregulation of ICAM-1 and P65, and attachment and invasion of circulating THP-1 monocytes. Strain field analysis revealed pressure-dependent spatial variation with 12% strain in the center of the chip, and 5% towards the ends. Pulsatile tensile strain reduced the inflammatory response to TNF- with a greater localized inflammatory response in areas of lower strain, further replicating in vivo behavior. In conclusion, we present a fully characterized, tri-culture model of the human coronary artery which recapitulates the physiological effects of pulsatile vessel dilation on morphology and localized inflammatory susceptibility. Our model was developed upon a commercially-available, organ-chip platform, allowing for rapid adoption for therapeutic testing, and fundamental discovery science.

bioengineering↗

bioRxiv2024

Myocardial infarction injury is exacerbated by nicotine in vape aerosol exposure

RationaleVaping is touted as a safer alternative to traditional cigarette smoking but the full spectrum of harm reduction versus comparable risk remains unresolved. Elevated bioavailability of nicotine in vape aerosol together with known risks of nicotine exposure may result in previously uncharacterized cardiovascular consequences of vaping. ObjectiveAssess the impact of nicotine exposure via vape aerosol inhalation upon myocardial response to infarction injury. Methods and ResultsFlavored vape juice containing nicotine (5 mg / ml) or vehicle alone (0 mg) was delivered using identical 4-week treatment protocols. Mice were subjected to acute myocardial infarction injury and evaluated for outcomes of cardiac structure and function. Findings reveal that nicotine exposure leads to worse outcomes with respect to contractile performance regardless of sex. Non-myocyte interstitial cell accumulation following infarction significantly increased with exposure to vape aerosol alone, but a comparable increase was not present when nicotine was included. ConclusionsMyocardial function after infarction is significantly decreased after exposure to nicotine vape aerosol irrespective of sex. Comparable loss of contractile function was not observed in mice exposed to vape aerosol alone, highlighting the essential role of nicotine in loss of contractile function. Increased vimentin immunoreactivity was observed in the vape alone group compared to control and vape nicotine. The correlation between vaping, interstitial cell responses, and cardiac remodeling leading to impaired contractility warrants further investigation. Public health experts seeking to reduce vaping-related health risks should consider messaging that highlights the increased cardiovascular risk especially with nicotine-containing aerosols.

molecular biology↗

bioRxiv2023

A comparison of the parasitoid wasp species richness of tropical forest sites in Peru and Uganda - subfamily Rhyssinae (Hymenoptera: Ichneumonidae)

The global distribution of parasitoid wasp species richness is poorly known. Past attempts to compare data from different sites have been hampered by small sample sizes and lack of standardisation. During the past decades, we have carried out long-term Malaise trapping using a standardised approach in the tropical forests of Peru (western Amazonia) and Uganda (eastern Africa). Here, we test how well such data can be used for global comparisons, by comparing the results for the subfamily Rhyssinae (Hymenoptera: Ichneumonidae). We found that more rhyssine species were caught in Peru than in Uganda, despite the Ugandan samples containing many more individuals both in absolute terms and per unit time. The difference in the number of individuals caught may largely be due to more rainfall in Peru, since rain reduces Malaise trap catches. Peruvian traps caught species at a faster rate (per individual caught) than Ugandan traps. We interpret this as a sign that the Peruvian sites have more species than the Ugandan site. Long-term, standardised Malaise trapping showed promise for global comparisons of species richness. Sampling more sites on both continents, and analysing all subfamilies, would give an estimate of which continent has more parasitoid wasp species. We suggest some refinements to the sampling design that would further improve sampling efficiency for future studies.

zoology↗