crisscrossing Science Episode 067: The Best Gift Your Mother Gave You

In this episode, Mike Crosser (professor of physics at Linfield College) and Chad Tillberg (professor of biology at Linfield College) invite Dr. Megan Bestwick (assistant professor of chemistry at Linfield College) to discuss her primary research topic, mitochondria. Mitochondria are organelles within our cells that ultimately create the energy currency that our cells need in order to do anything. Crosser, Tillberg, and Bestwick discuss the processes of mitochondria, how they are useful in forensics, and where they came from

The effect of short-term kaempferol exposure on reactive oxygen levels and integrity of human (HL-60) leukaemic cells

AbstractFlavonoids may be a principal contributor to the cancer preventative activity of fruit- and vegetable-rich diets and there is interest in their use as dietary supplements. However, there is potential conflict between the cytoprotective and cytotoxic activities of flavonoids, and their efficacy as anti-cancer agents is unresolved. Here, the integrity and survival of HL-60 promyelocytic leukaemia cells following short-term (90 min) exposure to the dietary abundant flavonoid kaempferol (1–100 μM) is reported. Supplementation initially decreased reactive oxygen levels but, paradoxically, a dose-dependent increase in single-strand DNA breakage occurred. However, there was no increase in oxidised DNA purines or membrane damage. Following a 24-h recovery period in non-kaempferol supplemented media, DNA single-strand breakage had declined and kaempferol exposed and control cultures possessed similar reactive oxygen levels. A reduction in 3H-thymidine incorporation occurred with ≥10 μM kaempferol. One hundred micromolar kaempefrol increased the proportion of cells in G2-M phase, the proportion of cells with a sub-G1 DNA content and enhanced ‘active’ caspase-3 expression but only induced a loss of mitochondrial membrane potential within a minority of cells. The relevance of induced DNA damage within a non-overtly oxidatively stressed environment to the disease preventative and therapeutic use of kaempferol is discussed

Invasive Plants Are a Valuable Alternate Protein Source and Can Contribute to Meeting Climate Change Targets

This work was funded by the Scottish Government through RESAS as part of its strategic research programme. We would like to thank William Rees and Teresa Grohmann for their time in helping with preparation of the manuscript. Jacqueline Wallace (Rowett Institute) and Robin Walker (SRUC) for providing plant samples. Donna Henderson and Jodie Park for technical assistance in NSP measurements. Susan Anderson for technical assistance in amino acid profiling. Gary Duncan and Lorraine Scobbie for technical assistance in phenolic profiling. Lisa Guerrier, Salomé Leveque (IUT- Clermont-Ferrand, France), who assisted and observed procedures as part of their lab-skill training. We would also like to thank Graham Horgan (BIOSS, Rowett Institute) for advise on the statistical analysis. We would like to thank the NHS for its incredible commitment to keeping us safe during these harsh times.Peer reviewedPublisher PD

Non-immortalized human tenocyte cultures as a vehicle for understanding cellular aspects to tendinopathy

The biochemical mechanisms underlying tendinopathy are obscure. We briefly describe preliminary observations of human tenocyte behaviour in culture as a vehicle for determining the role of reactive oxygen in tendon patholog

Unconventional Josephson Effect in Hybrid Superconductor-Topological Insulator Devices

We report on transport properties of Josephson junctions in hybrid superconducting-topological insulator devices, which show two striking departures from the common Josephson junction behavior: a characteristic energy that scales inversely with the width of the junction, and a low characteristic magnetic field for suppressing supercurrent. To explain these effects, we propose a phenomenological model which expands on the existing theory for topological insulator Josephson junctions

Three-dimensional dental microwear in type-Maastrichtian mosasaur teeth (Reptilia, Squamata)

Mosasaurs (Squamata, Mosasauridae) were large aquatic reptiles from the Late Cretaceous that filled a range of ecological niches within marine ecosystems. The type-Maastrichtian strata (68–66 Ma) of the Netherlands and Belgium preserve remains of five species that seemed to have performed different ecological roles (carnivores, piscivores, durophages). However, many interpretations of mosasaur diet and niche partitioning are based on qualitative types of evidence that are difficult to test explicitly. Here, we apply three-dimensional dental microwear texture analysis (DMTA) to provide quantitative dietary constraints for type-Maastrichtian mosasaurs, and to assess levels of niche partitioning between taxa. DMTA indicates that these mosasaurs did not exhibit neatly defined diets or strict dietary partitioning. Instead, we identify three broad groups: (i) mosasaurs Carinodens belgicus and Plioplatecarpus marshi plotting in the space of modern reptiles that are predominantly piscivorous and/or consume harder invertebrate prey, (ii) Prognathodon saturator and Prognathodon sectorius overlapping with extant reptiles that consume larger amounts of softer invertebrate prey items, and (iii) Mosasaurus hoffmanni spanning a larger plot area in terms of dietary constraints. The clear divide between the aforementioned first two groups in texture-dietary space indicates that, despite our small sample sizes, this method shows the potential of DMTA to test hypotheses and provide quantitative constraints on mosasaur diets and ecological roles

Scanning electron microscopy for blood micro-crystals in aortic stenosis patients.

BACKGROUND: Micro-crystals of calcium phosphate have been detected on the aortic valve of patients with aortic stenosis using scanning electron microscopy. It is not known whether crystalisation is specific to heart valve tissue or a general blood-derived process. METHODS: To this end we modified the method to determine whether calcium phosphate micro-crystals were present in the blood of patients with aortic stenosis. The method was first validated by adding synthetic calcium phosphate hydroxyapatite micro-crystals to healthy volunteer blood samples and determining the lower limit of detection. Then the method was used to examine the blood of 63 patients with echocardiographically confirmed aortic stenosis and 69 unaffected controls undergoing echocardiography for other reasons. Serum calcium and phosphate were measured and the calcium phosphate product compared in cases and controls. RESULTS: In the validation study, synthetic hydroxyapatite micro-crystals were identified down to a lower concentration limit of 0.008mg/mL. In the experimental study no particles were identified in any patient, with or without aortic stenosis, even though serum calcium phosphate was higher in cases compared with controls 2.6mmol/L (2.58-2.77) versus 2.47mmol/L (2.36-2.57), p = 0.005 for the difference. CONCLUSION: The results of our study confirm a positive association between serum calcium phosphate and aortic stenosis, but indicate that the calcium phosphate particles found in valve tissue do not precipitate freely in the blood

Interplay of chiral and helical states in a Quantum Spin Hall Insulator lateral junction

We study the electronic transport across an electrostatically-gated lateral junction in a HgTe quantum well, a canonical 2D topological insulator, with and without applied magnetic field. We control carrier density inside and outside a junction region independently and hence tune the number and nature of 1D edge modes propagating in each of those regions. Outside the 2D gap, magnetic field drives the system to the quantum Hall regime, and chiral states propagate at the edge. In this regime, we observe fractional plateaus which reflect the equilibration between 1D chiral modes across the junction. As carrier density approaches zero in the central region and at moderate fields, we observe oscillations in resistance that we attribute to Fabry-Perot interference in the helical states, enabled by the broken time reversal symmetry. At higher fields, those oscillations disappear, in agreement with the expected absence of helical states when band inversion is lifted.Comment: 5 pages, 4 figures, supp. ma

Incorporating DNA Sequencing into Current Prenatal Screening Practice for Down's Syndrome

PMCID: PMC3604109This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited