Transformation of 1,1,1-trichloroethane in an anaerobic packed-bed reactor at various concentrations of 1,1,1-trichloroethane, acetate and sulfate

Biotransformation of 1,1,1-trichloroethane (CH3CCl3) was observed in an anaerobic packed-bed reactor under conditions of both sulfate reduction and methanogenesis. Acetate (1 mM) served as an electron donor. CH3CCl3 was completely converted up to the highest investigated concentration of 10 µM. 1,1-Dichloroethane and chloroethane were found to be the main transformation products. A fraction of the CH3CCl3 was completely dechlorinated via an unknown pathway. The rate of transformation and the transformation products formed depended on the concentrations of CH3CCl3, acetate and sulfate. With an increase in sulfate and CH3CCl3 concentrations and a decrease in acetate concentration, the degree of CH3CCl3 dechlorination decreased. Both packed-bed reactor studies and batch experiments with bromoethanesulfonic acid, an inhibitor of methanogenesis, demonstrated the involvement of methanogens in CH3CCl3 transformation. Batch experiments with molybdate showed that sulfate-reducing bacteria in the packed-bed reactor were also able to transform CH3CCl3. However, packed-bed reactor experiments indicated that sulfate reducers only had a minor contribution to the overall transformation in the packed-bed reactor.

Hyperparasitoids Use Herbivore-Induced Plant Volatiles to Locate Their Parasitoid Host

Abstract Plants respond to herbivory with the emission of induced plant volatiles. These volatiles may attract parasitic wasps (parasitoids) that attack the herbivores. Although in this sense the emission of volatiles has been hypothesized to be beneficial to the plant, it is still debated whether this is also the case under natural conditions because other organisms such as herbivores also respond to the emitted volatiles. One important group of organisms, the enemies of parasitoids, hyperparasitoids, has not been included in this debate because little is known about their foraging behaviour. Here, we address whether hyperparasitoids use herbivore-induced plant volatiles to locate their host. We show that hyperparasitoids find their victims through herbivore-induced plant volatiles emitted in response to attack by caterpillars that in turn had been parasitized by primary parasitoids. Moreover, only one of two species of parasitoids affected herbivore-induced plant volatiles resulting in the attraction of more hyperparasitoids than volatiles from plants damaged by healthy caterpillars. This resulted in higher levels of hyperparasitism of the parasitoid that indirectly gave away its presence through its effect on plant odours induced by its caterpillar host. Here, we provide evidence for a role of compounds in the oral secretion of parasitized caterpillars that induce these changes in plant volatile emission. Our results demonstrate that the effects of herbivore-induced plant volatiles should be placed in a community-wide perspective that includes species in the fourth trophic level to improve our understanding of the ecological functions of volatile release by plants. Furthermore, these findings suggest that the impact of species in the fourth trophic level should also be considered when developing Integrated Pest Management strategies aimed at optimizing the control of insect pests using parasitoids

Extrusion texturization of cricket flour and soy protein isolate: Influence of insect content, extrusion temperature, and moisture‐level variation on textural properties

Due to the increasing global population and unsustainable meat production, the future supply of animal-derived protein is predicted to be insufficient. Currently, edible insects are considered as a potential and “novel” source of protein in the development of palatable meat analogues. This research used high moisture extrusion cooking (HMEC), at a screw speed of 150 rpm, to produce meat analogues using full- or low-fat cricket flours (CF) and soy protein isolate (SPI). Effects of water flow rate (WFR), cooking temperature (9 and 10 ml/min; 120, 140, and 160°C, respectively), and CF inclusions levels of 0, 15, 30, and 45% were analyzed. Cooking temperature and CF inclusion had a significant effect (p < .05) on both tensile stress in parallel and perpendicular directions, while WFR had no significant effect (p = .3357 and 0.7700), respectively. The tensile stress increased with temperature but decreased with CF inclusion at both WFRs. Comparatively, the tensile stress was stronger at WFR of 9 ml/min than at 10 ml/min; however, the tensile stress in parallel was mostly greater than tensile stress in perpendicular directions. Fibrous meat analogues with high anisotropic indices (AIs) of up to 2.80 were obtained, particularly at WFR of 10 ml/min and at inclusions of 30% low-fat CF. By controlling HMEC conditions, full-/low-fat cricket flours at 15% and 30% inclusions can offer an opportunity to partially substitute SPI in manufacturing of fibrous meat analogues

Experimental study system of the four-trophic-level community on <i>Brassica oleracea</i> plants.

<p>The gregarious primary parasitoid <i>Cotesia glomerata</i> (CG) and the solitary <i>C. rubecula</i> (CR) attack caterpillars of <i>Pieris</i> (PR) butterflies, which are in turn attacked by several hyperparasitoids: <i>Acrolyta nens</i> (1), <i>Lysibia nana</i> (2), <i>Pteromalus semotus</i> (3), <i>Mesochorus gemellus</i> (4), and <i>Baryscapus galactopus</i> (5). Hyperparasitoids at the fourth trophic level find their primary parasitoid host at the third trophic level via information derived from the plant at the first trophic level. Larvae of primary parasitoids that develop in their herbivorous host at the second trophic level inflict changes in their herbivore host, and the combination of herbivore and parasitoid (parasitized herbivores) inflict changes in plant volatile emission (I). These changes in plant volatile emission are used by hyperparasitoids as a cue of host presence (II). Photograph credit: Tibor Bukovinszky.</p

Hyperparasitoid species and the number of hyperparasitoid wasps emerging from <i>Cotesia glomerata</i> and <i>C. rubecula</i> cocoons collected during a 3-year survey.

<p>The numbers represent individual cocoons of the two parasitoids from which either a primary parasitoid or a hyperparasitoid emerged.</p>1<p><i>Baryscapus galactopus</i> is a gregarious hyperparasitoid that develops with on average eight individuals in a single <i>C. rubecula</i> cocoon. The numbers for <i>B. galactopus</i> represent individual <i>Cotesia</i> cocoons that were hyperparasitized by <i>B. galactopus</i> (and thus on average produced eight hyperparasitoids). The number of cocoons of the gregarious <i>C. glomerata</i> that were hyperparasitized was calculated by dividing the total number of emerging <i>B. galactopus</i> by eight.</p>2<p>Number indicates the collected number of cocoon clutches, from which 25,170 <i>C. glomerata</i> wasps emerged.</p

Preference of hyperparasitoids for herbivore-induced plant volatiles.

<p>Preference of the hyperparasitoid <i>Lysibia nana</i> for herbivore-induced plant volatiles was tested by using a full factorial design of two-choice olfactometer tests including pair-wise comparisons of the treatments: undamaged plants (white bars), <i>Pieris rapae</i> damaged plants (light grey), plants damaged by <i>Pieris rapae</i> caterpillars parasitized by <i>Cotesia glomerata</i> (dark grey bars), or plants damaged by <i>Pieris rapae</i> caterpillars parasitized by <i>C. rubecula</i> (black bars). The two lowest pairs of bars show the preference of <i>L. nana</i> for plants treated with caterpillar regurgitant. The first pair shows hyperparasitoid preference when plants are artificially damaged and regurgitant of unparasitized (light grey) or parasitized (dark grey) caterpillars was applied. The second and lowest pair shows that hyperparasitoids do not respond to the application of regurgitant without artificially damaging the plant. Numbers between brackets indicate the number of wasps that made a choice within 10 min from the start of the experiment versus the total number of wasps tested. * <i>p</i><0.05, ** <i>p</i><0.001. Photograph credit: Tibor Bukovinszky.</p

Herbivore-induced plant volatiles mediate hyperparasitism in the field.

<p>Percentage of <i>Cotesia glomerata</i> (CG, left) and <i>C. rubecula</i> (CR, right) cocoon clutches hyperparasitized on plants that had been induced with herbivory by unparasitized or parasitized caterpillars of <i>P. rapae</i>. <i>Pieris rapae</i> (PR), <i>P. rapae</i> parasitized by <i>C. glomerata</i> (PR-CG), <i>P. rapae</i> parasitized by <i>C. rubecula</i> (PR-CR), and undamaged (UD). Letters indicate significant differences between treatment groups (GLM, <i>p</i><0.05). Photograph credit: Tibor Bukovinszky.</p

Performance of <i>Lysibia nana</i> on pupae of two parasitoid species.

<p><i>Lysibia nana</i> dry mass plotted against the mass of the <i>Cotesia</i> cocoon before <i>L. nana</i> had parasitized the cocoon. Orange symbols represent wasps emerging from <i>C. glomerata</i> cocoons, and black symbols those emerging from <i>C. rubecula</i> cocoons. Females are represented by dots, and males by triangles. Photograph credit: Tibor Bukovinszky.</p

The effect of plant induction treatment on the fraction of primary parasitoid cocoons per plant that contained any hyperparasitoid in the field.

<p>Boldface type presents significant effects (α = 0.05) in a GLM model with a binomial distribution.</p

<i>Lysibia nana</i> responses in choice tests with primary parasitoid cocoons.

<p><i>Lysibia nana</i> preference (top bar) for gregarious broods of <i>Cotesia glomerata</i> (grey) or solitary cocoons of <i>C. rubecula</i> (white) in a Petri dish bioassay. <i>Lysibia nana</i> preference (lower bar) for gregarious broods of <i>Cotesia glomerata</i> (grey) or the same number of cocoons of <i>C. rubecula</i> (white). Numbers between brackets indicate the fraction of wasps that responded to cocoons within 10 min from the start of the experiment. * <i>p</i><0.05, ** <i>p</i><0.001. Photograph credit: Tibor Bukovinszky.</p