Prospects,challenges and current status of RNAi through insect feeding

RNA interference is a phenomenon in which the introduction of double‐stranded RNA (dsRNA) into cells triggers the degradation of the complementary messenger RNA in a sequence‐specific manner. Suppressing expression of vital genes could lead to insect death, therefore this technology has been considered as a potential strategy for insect pest control. There are three main routes of dsRNA administration into insects: (i) injections to the hemolymph, (ii) topical, and (iii) feeding. In this review, we focus on dsRNA administration through feeding. We summarize novel strategies that have been developed to improve the efficacy of this method, such as the use of nano‐based formulations, engineered microorganisms, and transgenic plants. We also expose the hurdles that have to be overcome in order to use this technique as a reliable pest management method. © 2019 Society of Chemical Industry     

The effect on root geotropism of certain ortho-carboxyphenylpropanones

A series of compounds related to 1-(2′-carboxyphenyl)-3-phenylpropane-1,3-dione has been synthesised and their effects on root geotropism assessed using cress and ryegrass seedlings. The more active members have been found to be highly potent, abolishing root geotropism at concentrations as low as 0.01 mg/litre. In this respect they compare favourably with TIBA and NPA. It is suggested that a 2-carboxy-phenyl radical separated by a 3 carbon unit from a second aromatic ring is essential for activity, and that a C-1 oxygen function enhances the effect.     

Behavioural responses of Aphis fabae to isothiocyanates in the laboratory and field

Isothiocyanates have been shown to stimulate olfactory receptors on the antennae of the black bean aphid, Aphis fabae Scop. Single-cell recording techniques show that this aphid has receptors at the proximal primary rhinarium which are sensitive to n-butyl isothiocyanate. In laboratory assays, 4-pentenyl and n-butyl isothiocyanates were repellent at similar threshold concentrations. A. fabae was attracted to host-plant odour, but addition of either isothiocyanate to the airstream masked this attraction. Field trials on spring beans did not produce any consistent reduction in numbers of alate or apterous aphids on the crop, and yields were not improved by either compound.     

Response to the Views and Opinions of Maningat,Seib, and Bassi Regarding McCleary et al (2013)

Phosphate cross‐linked starch, referred to as resistant starch 4 (RS₄) is hydrolyzed much more rapidly under physiological conditions (i.e., pH 6, 37°C, pancreatic α‐amylase) than under the conditions used in AOAC dietary fiber method 985.29/AACC International Approved Method 32‐45.01 (the Prosky method), in which samples are incubated with thermostable bacterial α‐amylase at 95–100°C. For this reason, the author concludes that the Prosky method overestimates the dietary fiber content of these materials. A more accurate estimate of dietary fiber content is obtained with AOAC Method 2009.01/AACCI Approved Method 32‐45.01.     

Agelasine Diterpenoids and Cbl-b Inhibitory Ageliferins from the Coralline Demosponge Astrosclera willeyana

An extract of the coralline demosponge Astrosclera willeyana inhibited the ubiquitin ligase activity of the immunomodulatory protein Cbl-b. The bioassay-guided separation of the extract provided ten active compounds, including three new N-methyladenine-containing diterpenoids, agelasines W–Y (1–3), a new bromopyrrole alkaloid, N(1)-methylisoageliferin (4), and six known ageliferin derivatives (5–10). The structures of the new compounds were elucidated from their spectroscopic and spectrometric data, including IR, HRESIMS, and NMR, and by comparison with spectroscopic data in the literature. While all of the isolated compounds showed Cbl-b inhibitory activities, ageliferins (4–10) were the most potent metabolites, with IC₅₀ values that ranged from 18 to 35 μM.     

Anterior cingulate: single neuronal signals related to degree of reward expectancy

As monkeys perform schedules containing several trials with a visual cue indicating reward proximity, their error rates decrease as the number of remaining trials decreases, suggesting that their motivation and/or reward expectancy increases as the reward approaches. About one-third of single neurons recorded in the anterior cingulate cortex of monkeys during these reward schedules had responses that progressively changed strength with reward expectancy, an effect that disappeared when the cue was random. Alterations of this progression could be the basis for the changes from normal that are reported in anterior cingulate population activity for obsessive-compulsive disorder and drug abuse, conditions characterized by disturbances in reward expectancy.