Wildcat population density in NE Portugal: A regional stronghold for a nationally threatened felid

Population density data on depleted and endangered wildlife species are essential to assure their effective management and, ultimately, conservation. The European wildcat is an elusive and threatened species inhabiting the Iberian Peninsula, with fragmented populations and living in low densities. We fitted spatial capture–recapture models on camera-trap data, to provide the first estimate of wildcat density for Portugal and assess the most influential drivers determining it. The study was implemented in Montesinho Natural Park (NE Portugal), where we identified nine individuals, over a total effort of 3,477 trap-nights. The mean density estimate was 0.032 ± 0.012 wildcat/km², and density tended to increase with distance to humanized areas, often linked to lower human disturbance and domestic cat presence, with forest and herbaceous vegetation cover and with European rabbit abundance. Although, this density estimate is within the range of values estimated for protected areas elsewhere in the Iberian Peninsula, our estimates are low at the European level. When put in context, our results highlight that European wildcats may be living in low population densities across the Iberian Mediterranean biogeographic region. No phenotypic domestic or hybrid cats were detected, suggesting potentially low admixture rates between the two species, although genetic sampling would be required to corroborate this assertion. We provide evidence that Montesinho Natural Park may be a suitable area to host a healthy wildcat population, and thus be an important protected area in this species' conservation context.     

Early physiological responses of Abies alba and Rubus fruticosus to ungulate herbivory

For the last 50 years, Chamois (Rupicapra rupicapra) population exponentially increased in the French Alps. This herbivore faces a food shortage in the winter; its diet mainly includes woody species (Abies alba Mill.) and brambles (Rubus fruticosus). The physiological response following simulated herbivory of these two plants was assessed. More precisely, the effects of leaf clipping and ungulate saliva application on the epidermal flavonoids and chlorophyll contents were considered as an induced structural response. The chlorophyll fluorescence (Fv/Fm) was also measured to provide information on the photosynthesis status as an induced functional response. The non-invasive techniques used in this experiment highlighted an induced response, emerging during the days following the simulated herbivory. R. fruticosus was drastically affected, photosynthesis was disturbed (decreased Fv/Fm) and mortality began on day 5 reaching 100 % less than 1 week later. Physiological parameters were also affected in A. alba (slight decrease of Fv/Fm and lower content of flavonoids), but this species recovered and survived no matter what the stressing treatment was. These results did not point out an efficient repulsive-induced response of A. alba and R. fruticosus to herbivory. The existence of constitutive defences such as prickles (R. fruticosus) or low-digestible tannins (A. alba) is no more efficient to escape from ungulates consumption. Nevertheless, in spite of the increase of the ungulates exponential demography, these two plants do not face rarefaction problem in the French Alps. Thus, survival of A. alba stands is probably linked to the recovery ability of saplings, when R. fruticosus stands maintain themselves thanks to the strong resprouting capacity of this species.     

The molecular targets of ivermectin and lotilaner in the human louse Pediculus humanus humanus: New prospects for the treatment of pediculosis

Control of infestation by cosmopolitan lice (Pediculus humanus) is increasingly difficult due to the transmission of parasites resistant to pediculicides. However, since the targets for pediculicides have no been identified in human lice so far, their mechanisms of action remain largely unknown. The macrocyclic lactone ivermectin is active against a broad range of insects including human lice. Isoxazolines are a new chemical class exhibiting a strong insecticidal potential. They preferentially act on the γ-aminobutyric acid (GABA) receptor made of the resistant to dieldrin (RDL) subunit and, to a lesser extent on glutamate-gated chloride channels (GluCls) in some species. Here, we addressed the pediculicidal potential of isoxazolines and deciphered the molecular targets of ivermectin and the ectoparasiticide lotilaner in the human body louse species Pediculus humanus humanus. Using toxicity bioassays, we showed that fipronil, ivermectin and lotilaner are efficient pediculicides on adult lice. The RDL (Phh-RDL) and GluCl (Phh-GluCl) subunits were cloned and characterized by two-electrode voltage clamp electrophysiology in Xenopus laevis oocytes. Phh-RDL and Phh-GluCl formed functional homomeric receptors respectively gated by GABA and L-glutamate with EC₅₀ values of 16.0 μM and 9.3 μM. Importantly, ivermectin displayed a super agonist action on Phh-GluCl, whereas Phh-RDL receptors were weakly affected. Reversally, lotilaner strongly inhibited the GABA-evoked currents in Phh-RDL with an IC₅₀ value of 40.7 nM, whereas it had no effect on Phh-GluCl. We report here for the first time the insecticidal activity of isoxazolines on human ectoparasites and reveal the mode of action of ivermectin and lotilaner on GluCl and RDL channels from human lice. These results emphasize an expected extension of the use of the isoxazoline drug class as new pediculicidal agents to tackle resistant-louse infestations in humans.     

Gentamicin palmitate as a new antibiotic formulation for mixing with bone tissue and local release

During surgery with bone grafting, the impaction of bone tissue creates an avascular area where local circulation is disrupted. If infections arise, they may prevent systemically administered antibiotics from reaching the infected bone. In this study we evaluated gentamicin palmitate (GP) mixed with gentamicin sulfate (GS) as a coating for bone chips (BCh). The efficacy of the coated BCh was measured by gentamicin base release tests using B. subtilis, S. epidermidis and S. aureus. Gentamicin base release was evaluated in phosphate-buffered saline for up to 7 days using B. subtilis bioassay. Antimicrobial efficacy was tested with S. aureus and S. epidermidis. A significant difference on the release of gentamicin base between GS and GS + GP was observed. S. epidermidis are significantly more susceptible to GS + GP and GS than S. aureus. BCh can act as gentamicin carriers and showed efficacy against S. aureus and S. epidermidis.