Protein Hydrolysates Are Avoided by Herbivores but Not by Omnivores in Two-Choice Preference Tests

Background: The negative sensory properties of casein hydrolysates (HC) often limit their usage in products intended for human consumption, despite HC being nutritious and having many functional benefits. Recent, but taxonomically limited, evidence suggests that other animals also avoid consuming HC when alternatives exist. Methodology/Principal Findings: We evaluated ingestive responses of five herbivorous species (guinea pig, mountain beaver, gopher, vole, and rabbit) and five omnivorous species (rat, coyote, house mouse, white-footed mouse, and deer mouse; N = 16–18/species) using solid foods containing 20% HC in a series of two-choice preference tests that used a nonprotein, cellulose-based alternative. Individuals were also tested with collagen hydrolysate (gelatin; GE) to determine whether it would induce similar ingestive responses to those induced by HC. Despite HC and GE having very different nutritional and sensory qualities, both hydrolysates produced similar preference score patterns. We found that the herbivores generally avoided the hydrolysates while the omnivores consumed them at similar levels to the cellulose diet or, more rarely, preferred them (HC by the white-footed mouse; GE by the rat). Follow-up preference tests pairing HC and the nutritionally equivalent intact casein (C) were performed on the three mouse species and the guinea pigs. For the mice, mean HC preference scores were lower in the HC v C compared to the HC v Cel tests, indicating that HC’s sensory qualities negatively affected its consumption. However, responses were species-specific. For the guinea pigs, repeated exposure to HC or C (4.7-h sessions; N = 10) were found to increase subsequent HC preference scores in an HC v C preference test, which was interpreted in the light of conservative foraging strategies thought to typify herbivores. Conclusions/Significance: This is the first empirical study of dietary niche-related taxonomic differences in ingestive responses to protein hydrolysates using multiple species under comparable conditions. Our results provide a basis for future work in sensory, physiological, and behavioral mechanisms of hydrolysate avoidance and on the potential use of hydrolysates for pest management

Diversidade de Parasitóides (Hymenoptera: Braconidae e Figitidae) de larvas frugívoras (Diptera: Tephritidae e Lonchaeidae) na Reserva Florestal Adolpho Ducke, Amazônia Ocidental, Manaus, Brasil

This study aimed to identify parasitoid species of frugivorous larvae and to describe the tritrophic interactions involving wild fruits, frugivorous insects and their natural enemies at Adolpho Ducke Forest Reserve (RFAD) (Manaus, AM, Brazil). Collections were performed in four 1 km2 quadrants in the corners of the RFAD. The wild fruits were collected inside the forest in access trails leading to each collection area and in trails that surrounded the quadrants, up to five metres from the trail on each side. The fruits were placed in plastic containers covered with thin fabric, with a vermiculite layer on the base to allow the emergence of flies or parasitoids. Seven Braconidae species were collected, distributed among Opiinae: Doryctobracon areolatus (Szépligeti, 1911), Utetes anastrephae (Viereck, 1913), and Opius sp., and Alysiinae: Asobara anastrephae (Muesebeck, 1958), Phaenocarpa pericarpa Wharton and Carrejo, 1999, Idiasta delicata Papp, 1969, and Asobara sp. Parasitism rates by braconids and figitids are presented. Doryctobracon areolatus was the most frequent, parasitizing the highest number of fly species, and showing the highest parasitism percentage in larvae feeding on Micropholis williamii fruits. The collected figitids belong to Aganaspis nordlanderi Wharton, 1998 and A. pelleranoi (Brethes, 1924). All 15 tritrophic associations are new records for the Brazilian Amazon region. The RFAD is an important natural reservoir of frugivorous larvae parasitoids

The in vitro susceptibility of Campylobacter spp. to the antibacterial effect of manuka honey

We report the antimicrobial effect of manuka honey against Campylobacter spp. isolated by a diagnostic laboratory from specimens from a community in New Zealand. The isolates were differentiated according to species level using multiplex PCR. C. jejuni (20 strains) and C. coli (7 strains) were identified. The clinical isolates identified and type culture collection strains of these species were subjected to testing to determine the minimum inhibitory concentration (MIC) of manuka honey using a microdilution technique. The MIC of the manuka honey against all of the Campylobacter tested was found to be around 1% (v/v) honey. The low MIC values suggest that honey might still inhibit the growth of campylobacteria after dilution by fluid in the gut, but the actual concentration of honey that can be achieved in the intestine is unknown. Therefore, clinical investigation is required to establish the efficacy of honey against Campylobacter spp. in the gut environment

Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye

In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an electrochemical cell with 0.2L of solution containing 100mgdm(-3) of the textile dye Acid Red 1 (AR1) using Na2SO4 as supporting electrolyte, applying 7.5 and 60mAcm(-2). From the voltammetric curves, it was possible to understand that Ti/TiO2-nanotubes/PbO2 electrode has high oxygen evolution overpotential than Ti/Pt anode. A direct electron transfer reaction is attained between the dye molecules and Ti/Pt surface, at lower currents. Conversely, the AR1 oxidation involves water decomposition intermediates, mainly OH radicals at Ti/TiO2-nanotubes/PbO2 anode. The electrolytic process was monitored by the UV-visible spectrometry and the chemical oxygen demand (COD). Results clearly show that Ti/TiO2-nanotubes/PbO2 anode performs better than Ti/TiO2 in removing ARI due to the electrosynthesis of strong oxidants on its surface (OH and persulfates), achieving a higher oxidation rate, higher current efficiency, and less energy consumption than Ti/Pt electrode