Biology subjects

Robinson, A. P.

Publications and source records attributed to Robinson, A. P..

4 recordsLinked to original sources

bioRxiv2020

Disentangling the role of surface topography and intrinsic wettability in the prey capture mechanism of Nepenthes pitcher plants

Nepenthes pitcher plants capture prey with leaves specialised as pitfall traps. Insects are trapped when they aquaplane on the pitcher rim (peristome), a surface structured with macroscopic and microscopic radial ridges. What is the functional significance of this hierarchical surface topography? Here, we use insect pad friction measurements, photolithography, wetting experiments and physical modelling to demonstrate that the ridges enhance the traps efficacy by satisfying two functional demands on prey capture: Macroscopic ridges restrict lateral but enhance radial spreading of water, thereby creating continuous slippery tracks which facilitate prey capture when little water is present. Microscopic ridges, in turn, ensure that the water film between insect pad and peristome remains stable, causing insects to aquaplane. In combination, the hierarchical ridge structure hence renders the peristome wettable, and water films continuous, so avoiding the need for a strongly hydrophilic surface chemistry, which would compromise resistance to desiccation and attract detrimental contamination.

plant biology↗

bioRxiv2019

Nanocatalytic activity of clean-surfaced, faceted nanocrystalline gold enhances remyelination in animal models of multiple sclerosis

Development of pharmacotherapies that promote remyelination are a high priority for multiple sclerosis (MS) due to their potential for neuroprotection and restoration of function through repair of demyelinated lesions. A novel preparation of clean-surfaced, faceted gold nanocrystals demonstrated robust remyelinating activity in response to demyelinating agents in both chronic cuprizone and acute lysolecithin rodent animal models. Furthermore, oral delivery of gold nanocrystals improved motor functions of cuprizone-treated mice in both open field and kinematic gait studies. Gold nanocrystal treatment of oligodendrocyte precursor cells in culture resulted in oligodendrocyte maturation and expression of key myelin differentiation markers. Additional in vitro data demonstrated that these gold nanocrystals act via a novel energy metabolism pathway involving the enhancement of key indicators of aerobic glycolysis. In response to gold nanocrystals, co-cultured central nervous system cells exhibited elevated levels of the redox coenzyme nicotine adenine dinucleotide (NAD+), elevated total ATP levels, elevated extracellular lactate levels, and upregulation of myelin-synthesis related genes, collectively resulting in functional myelin generation. Based on these preclinical studies, clean-surfaced, faceted gold nanocrystals represent a novel remyelinating therapeutic for multiple sclerosis.\n\nOne Sentence SummaryNanocatalytic activity of clean-surfaced, faceted gold nanocrystals results in robust remyelinating activity in demyelination animal models of multiple sclerosis.

neuroscience↗

bioRxiv2018

Sample-based regulatory intervention for managing risk within heterogeneous populations, with phytosanitary inspection of mixed consignments as a case study

Inspection of consignments of imported goods is commonly undertaken at national borders in order to prevent incursions of pests and diseases and deter malefactors. Inspection of the whole consignment is usually either impossible or inefficient, so inspection of a random sample is used instead.\n\nThe size of the random sample for plant products is justified by appeal to International Standards for Phytosanitary Measures No. 31, \"Methodologies for Sampling of Consignments\". ISPM 31 notes that \"A lot to be sampled should be a number of units of a single commodity identifiable by its homogeneity [...]\" and \"Treating multiple commodities as a single lot for convenience may mean that statistical inferences can not be drawn from the results of the sampling.\"\n\nHowever, commonly consignments are heterogeneous, either because the same commodities have multiple sources or because there are several different commodities. The ISPM 31 prescription creates a substantial impost on border inspection because it suggests that heterogeneous populations must be split into homogeneous sub-populations from which separate samples of nominal size must be taken.\n\nWe demonstrate that if consignments with known heterogeneity are treated as stratified populations and the random sample of units is allocated proportionally based on the number of units in each stratum, then the nominal sensitivity at the consignment level is achieved if our concern is the level of contamination in the entire consignment taken as a whole. We argue that unknown heterogeneity is no impediment to appropriate statistical inference. We conclude that the international standard is unnecessarily restrictive.

ecology↗

bioRxiv2018

Risk Factors for Fouling Biomass: Evidence from Small Vessels in Australia

Invasive marine non-indigenous species are a major threat to marine biodiversity and marine related industries. Recreational vessels are recognised as an important vector of non-indigenous species translocation, particularly the secondary translocation of species domestically.\n\nThis paper reports on a novel application of multilevel modelling and multiple imputation to biomass samples gathered from the hull and other external surfaces of recreational yachts and fishing vessels in order to quantify the relationship between the wet biomass of biofouling and vessel-level characteristics. Unsurprisingly, we find that the number of days since the vessel was last cleaned was strongly related to the wet weight of biomass. The number of days since the vessel was last used was also related to the wet weight of biomass, yet differed depending on the vessel type. Similarly, the median number of trips undertaken by the vessel was related to the wet weight of biomass, and varied according to the type of antifouling paint used by the vessel. The relationship between vessel size, as measured by hull surface area, and wet weight biomass per sample unit area was not significant.\n\nIn order to reduce the international and domestic spread of invasive species, small vessel owners should use an appropriate type of antifouling paint that suits their vessels operational profile, and be encouraged to maintain a maintenance

ecology↗