Effects of dietary exposure to plant toxins on bioaccumulation, survival, and growth of black soldier fly (Hermetia illucens) larvae and lesser mealworm (Alphitobius diaperinus)

In their natural habitat, insects may bioaccumulate toxins from plants for defence against predators. When insects are accidently raised on feed that is contaminated with toxins from co-harvested herbs, this may pose a health risk when used for human or animal consumption. Plant toxins of particular relevance are the pyrrolizidine alkaloids (PAs), which are genotoxic carcinogens produced by a wide variety of plant species and the tropane alkaloids (TAs) which are produced by a number of Solanaceae species. This study aimed to investigate the transfer of these plant toxins from substrates to black soldier fly larvae (BSFL) and lesser mealworm (LMW). PAs and the TAs atropine and scopolamine were added to insect substrate simulating the presence of different PA- or TA-containing herbs, and BSFL and LMW were grown on these substrates. Bioaccumulation from substrate to insects varied widely among the different plant toxins. Highest bioaccumulation was observed for the PAs europine, rinderine and echinatine. For most PAs and for atropine and scopolamine, bioaccumulation was very low. In the substrate, PA N-oxides were quickly converted to the corresponding tertiary amines. More research is needed to verify the findings of this study at larger scale, and to determine the potential role of the insect and/or substrate microbiome in metabolizing these toxins.

Simulation-based development: shaping clinical procedures for extra-uterine life support technology

BACKGROUND

Research into Artificial Placenta and Artificial Womb (APAW) technology for extremely premature infants (born < 28 weeks of gestation) is currently being conducted in animal studies and shows promising results. Because of the unprecedented nature of a potential treatment and the high-risk and low incidence of occurrence, translation to the human condition is a complex task. Consequently, the obstetric procedure, the act of transferring the infant from the pregnant woman to the APAW system, has not yet been established for human patients. The use of simulation-based user-centered development allows for a safe environment in which protocols and devices can be conceptualized and tested. Our aim is to use participatory design principles in a simulation context, to gain and integrate the user perspectives in the early design phase of a protocol for this novel procedure.

METHODS

Simulation protocols and prototypes were developed using an iterative participatory design approach; usability testing, including general and task-specific feedback, was obtained from participants with clinical expertise from a range of disciplines. The procedure made use of fetal and maternal manikins and included animations and protocol task cards.

RESULTS

Physical simulation with the active participation of clinicians led to the diffusion of tacit knowledge and an iteratively formed shared understanding of the requirements and values that needed to be implemented in the procedure. At each sequel, participant input was translated into simulation protocols and design adjustments.

CONCLUSION

This work demonstrates that simulation-based participatory design can aid in shaping the future of clinical procedure and product development and rehearsing future implementation with healthcare professionals.

Effects of pyrethroid and organophosphate insecticides on reared black soldier fly larvae (Hermetia illucens)

Black soldier fly larvae (Hermetia illucens) receive growing interest as a potential alternative animal feed source. These insects may be exposed to insecticide residues in the rearing substrate. This study aimed to investigate the effects of six different pyrethroid and organophosphate insecticides on this insect species' performance. The toxicity of two "model" substances for each of these classes (cypermethrin; pirimiphos-methyl) was quantified, with and without the synergist piperonyl butoxide (PBO). Critical effect doses corresponding to 10% yield (CED10) for cypermethrin (0.4 mg/kg) and pirimiphos-methyl (4.8 mg/kg) were determined. The addition of PBO to cypermethrin enhanced its relative potency with a factor 2.6. These data were compared against the relative toxicity of two analogue substances in each class (permethrin, deltamethrin; chlorpyrifos-methyl, malathion). Results suggest that exposure to concentrations complying with legal limits can cause significant reductions in yield. Exposure to multiple substances at lower concentrations resulted in negative additive and synergistic effects. Of the tested substances, deltamethrin was most toxic, causing 94% yield at 0.5 mg/kg. Analytical results suggested that transfer of tested substances to the larval biomass was substance- and concentration-specific, but appeared to be correlated to reduced yields and the presence of PBO. Transfer of organophosphates was overall low (<2%), but ranged from 8% to 75% for pyrethroids. Due to very low limits in insect biomass (∼0.01 mg/kg), high transfer may result in noncompliance. It is recommended that rearing companies implement lower contractual thresholds, and that policymakers consider adjusting legally allowed maximum residue levels in insect feed.

The use of animal by-products in a circular bioeconomy: Time for a TSE road map 3?

In 2005 and 2010, the European Commission (EC) published two subsequent 'Road Maps' to provide options for relaxation of the bans on the application of animal proteins in feed. Since then, the food production system has changed considerably and demands for more sustainability and circularity are growing louder. Many relaxations envisioned in the second Road Map have by now been implemented, such as the use of processed animal proteins (PAPs) from poultry in pig feed and vice versa. However, some legislative changes, in particular concerning insects, had not been foreseen. In this article, we present a new vision on legislation for increased and improved use of animal by-products. Six current legislative principles are discussed for the bans on animal by-products as feed ingredients: feed bans; categorization of farmed animals; prohibition unless explicitly approved; approved processing techniques, the categorization of animal by-products, and monitoring methods. We provide a proposal for new guiding principles and future directions, and several concrete options for further relaxations. We argue that biological nature of farmed animals in terms of dietary preferences should be better recognised, that legal zero-tolerance limits should be expanded if safe, and that legislation should be revised and simplified.

Aflatoxin B1 Metabolism of Reared Alphitobius diaperinus in Different Life-Stages

The presence of carcinogenic aflatoxins in food and feed is a major issue. In prior studies, aflatoxin B1 (AfB1) and known primary metabolites were absent from Lesser Mealworm (LMW, Alphitobius diaperinus) reared on contaminated diets. LMW is a promising alternative protein source. The objectives of this stu\dy were to determine whether LMW can be reared on AfB1-contaminated feed in each life-stage, and to gather more insight into potential metabolites formed. Results suggested no adverse effects in terms of survival/growth when three stages of LMW (larvae, pre-pupae, beetles) were exposed to feed containing AfB1 concentrations of 200 and 600 µg/kg for 48 h. Insect and frass samples were analyzed by LC-MS/MS and high-resolution MS to, respectively, quantify concentrations of AfB1 and its major metabolites, and determine secondary metabolites. No AfB1 or major metabolites were quantified in the insect samples. Mass balance calculations showed that up to 40% of spiked AfB1 could be recovered in the frass, in the form of AfB1, aflatoxicol and AfM1. HRMS results suggested the presence of additional metabolites in the frass, but, due to lack of commercially available reference standards for these compounds, exact identification and quantification was not possible. More research is needed to verify the absence of toxicity.

Effects of insecticides on mortality, growth and bioaccumulation in black soldier fly (Hermetia illucens) larvae

Residues of persistent insecticides may be present in the substrates on which insects are reared for food and feed, which may affect insect growth or survival. In addition, insecticidal substances may bio-accumulate in reared insects. The objective of this study was to assess potential effects of selected insecticides on the growth and survival of black soldier fly larvae (BSFL, Hermetia illucens) and on their safety when used as animal feed. Six insecticides (chlorpyrifos, propoxur, cypermethrin, imidacloprid, spinosad, tebufenozide) with different modes of action were tested in two sequential experiments. Cypermethrin was also tested with the synergist piperonyl butoxide (PBO). Standard BSFL substrate was spiked to the respective maximum residue level (MRL) of each insecticide allowed by the European Union to occur in feed; and BSFL were reared on these substrates. Depending on the observed effects in the first experiment, spiked concentrations tested in the second experiment were increased or reduced. At the concentrations applied (1 and 10 times MRL), three of the six tested substances (chlorpyrifos, propoxur, tebufenozide) did not affect the survival or biomass growth of BSFL, compared to the control (non-spiked) treatments. At MRL, imidacloprid stimulated the growth of BSFL compared to the controls. Spinosad and cypermethrin at the MRL level negatively affected growth and survival. The effects of cypermethrin appeared to be augmented by addition of PBO. A mean bio-accumulation factor of ≤0.01 was found in both experiments for all substances-except for cypermethrin, which was comparatively high, but still below 1 (0.79 at 0.1 mg/kg). The lack of accumulation of insecticides in the larvae suggests that there is no risk of larval products being uncompliant with feed MRLs. However, we conclude that insecticides present in substrates may affect growth and survival of BSFL. More research on a larger variety of substances and insect species is recommended.

The aflatoxin situation in Africa: Systematic literature review

Contamination of African staple foods is a major issue for human and animal health, nutrition, and trade. This review aimed to collect and synthesize the available evidence on geographical spread, scale of contamination, disease burden, economic impact, and mitigation measures for aflatoxins in Africa by way of a systematic literature review. This knowledge can enhance management strategies for the major challenges to combat aflatoxins. The search was conducted by applying a predefined search strategy, using bibliographic databases and websites, covering the period 2010 to 2018. Results showed that maize, peanuts, and animal feeds were the most studied commodities. For maize, all studies indicated mean AFB₁ to exceed the European Union legal limit. From studies on contamination levels and biomarkers, it is clear that overall exposure is high, leading to a substantial increase in long-term disease burden. In addition, concentrations in food occasionally can reach very high levels, causing acute aflatoxicoses. The trade-related impact of aflatoxin contamination was mainly evaluated from the standpoint of aflatoxin regulation affecting products imported from Africa. There was a limited number of studies on health-related economic impacts, pointing out a gap in peer-reviewed literature. A number of mitigation measures have been developed, but proof of cost-effectiveness or even costs alone of the practices is often lacking. We recommend more emphasis to be put in peer-reviewed studies on evidence-based cost-effective mitigation strategies for aflatoxins, on the scale and spread of the problem and its impacts on public health and economics for use in evidence-based policies.

Cenozoic evolution of the steppe-desert biome in Central Asia

The origins and development of the arid and highly seasonal steppe-desert biome in Central Asia, the largest of its kind in the world, remain largely unconstrained by existing records. It is unclear how Cenozoic climatic, geological, and biological forces, acting at diverse spatial and temporal scales, shaped Central Asian ecosystems through time. Our synthesis shows that the Central Asian steppe-desert has existed since at least Eocene times but experienced no less than two regime shifts, one at the Eocene-Oligocene Transition and one in the mid-Miocene. These shifts separated three successive "stable states," each characterized by unique floral and faunal structures. Past responses to disturbance in the Asian steppe-desert imply that modern ecosystems are unlikely to recover their present structures and diversity if forced into a new regime. This is of concern for Asian steppes today, which are being modified for human use and lost to desertification at unprecedented rates.

Accelerated growth of orbital schwannomas during pregnancy does not correlate with sex hormone- or growth factor receptor status

Purpose: Until now, three cases of growth of an orbital schwannoma during pregnancy have been published. We aim to provide additional insight in the effect of pregnancy on orbital schwannomas. Methods: We present two additional cases of accelerated growth of orbital schwannomas during pregnancy and investigate receptor expression profiles for estrogen, progesterone, androgen, VEGF, EGF, FGF, PDGF-Rβ and ki-67 in the two pregnant cases and six non-pregnant cases. Results: Case 1: A 26-year-old woman developed unilateral exophthalmos during pregnancy, with normal visual acuity and ocular motility. During a subsequent pregnancy, again the exophthalmos progressed. MRI showed a mass suggestive of schwannoma. After delivery, resection of the lesion was performed through an anterior approach. Pathology confirmed schwannoma. The expression profile was positive for estrogen- and FGF receptors and ki-67, but negative for progesterone-, androgen- and other growth factor receptors. Case 2: A 24-year-old woman presented with diplopia and unilateral pain during pregnancy. She had normal visual acuity, but a mild exophthalmos and elevation deficit. MRI revealed an extraconal mass suggestive of schwannoma. After delivery, resection was performed through an anterior approach. Pathology confirmed the diagnosis. The expression profile was positive for ki-67, but negative for sex hormone- and growth factor receptors. In the six non-pregnant cases the expression profiles varied, with only one subject showing a strong expression of estrogen-, progesterone- and androgen receptors. Conclusions: Orbital schwannomas can experience growth during pregnancy. The underlying mechanism remains unclear as hormone- and growth factor expression profiles show no correlation to the pregnant state.

Bridging legal requirements and analytical methods: a review of monitoring opportunities of animal proteins in feed

Availability and safety of food ranks among the basic requirements for human beings. The importance of the food producing sector, inclusive of feed manufacturing, demands a high level of regulation and control. This paper will present and discuss the relationships in the triangle of legislation, the background of hazards with a biological nature, and opportunities for monitoring methods, most notable for prion-based diseases as primary issue. The European Union legislation for prevention of prion-based diseases since 2000 is presented and discussed. The definitions and circumscriptions of groups of species will be analysed in the view biological classification and evolutionary relationships. The state of the art of monitoring methods is presented and discussed. Methods based on visual markers (microscopy), DNA-based methods (PCR), protein-based methods (ELISA, mass spectroscopy, proteomics), near infrared oriented methods and combinations thereof are being evaluated. It is argued that the use in legislation of non-homogeneous groups of species in a biological sense will hamper the optimal design of monitoring methods. Proper definitions are considered to act as bridges between legal demands and suitable analytical methods for effective monitoring. Definitions including specified groups of species instead of single species are more effective for monitoring in a range of cases. Besides the desire of precise circumscription of animal groups targeted by legislation, processed products need well defined definitions as well. Most notable examples are blood versus blood products, and hydrolysis of several types of material. The WISE principle for harmonising the design of legislation and of analytical methods is discussed. This principle includes the elements Witful (reasonable legal principles), Indicative (clear limits between prohibition and authorisation), Societal demands (public health, environment, economy), and Enforceable (presence of suited monitoring methods) in order to promote a balanced effort for reaching the desired level of safety in the food production chain.

[A woman with acute bilateral vision loss]

A 46-year-old woman presented to the emergency department with progressive bilateral loss of vision followed by headache. She had been taking topiramate 25 mg daily for eight days before presentation. In the end, she was diagnosed with topiramate-induced acute glaucoma for which she received appropriate treatment.

FMRP is associated to the ribosomes via RNA

The FMR1 transcript is alternatively spliced and generates different splice variants coding for FMR1 proteins (FMRP) with a predicted molecular mass of 70-80 kDa. FMRP is widely expressed and localized in the cytoplasm. To study a possible interaction with other cellular components, FMRP was isolated and characterized under non-denaturing conditions. Under physiological salt conditions FMRP appears to have a molecular mass of > 600 kDa, indicating a binding to other cellular components. This interaction is disrupted in the presence of high salt concentrations. The dissociation conditions to free FMRP from the complex are similar to the dissociation of FMRP from RNA as shown before. The binding of FMRP from the complex is also disrupted by RNAse treatment. That the association of FMRP to a high molecular weight complex possibly occurs via RNA, is further supported by the observation that the binding of FMRP, containing an lle304Asn substitution, to the high molecular weight complex is reduced. An equal reduced binding of mutated FMRP to RNA in vitro was observed before under the same conditions. The reduced binding of FMRP with the lle304Asn substitution further indicates that the interaction to the complex indeed occurs via FMRP and not via other RNA binding proteins. In a reconstitution experiment where the low molecular mass FMRP (70-80 kDa) is mixed with a reticulocyte lysate (enriched in ribosomes) it was shown that FMRP can associate to ribosomes and that this binding most likely occurs via RNA.

Characterization of FMR1 proteins isolated from different tissues

FMR1 protein expression was studied in different tissues. In human, monkey and murine tissues, high molecular mass FMR1 proteins (67-80 kDa) are found, as shown in lymphoblastoid cells lines. The identity of these proteins was confirmed by their absence in tissues from patients with the fragile X syndrome and a FMR1 knock-out mouse. An Ile367Asn substitution in the FMR1 protein did not alter the translation, processing and localization of FMR1 proteins in lymphoblastoid cells from a patient carrying this mutation. All the high molecular mass FMR1 proteins isolated from normal lymphoblastoid cells and cells from the patient with the Ile367Asn substitution were able to bind RNA. However, the FMR1 proteins of the patient had reduced affinity for RNA binding at high salt concentrations. In some human, monkey and murine tissues low molecular mass FMR1 proteins (39-41 kDa) were found, which had the same N terminus as the 67-90 kDa isoforms, but differ in their C terminus and are therefore most likely the result of carboxy-terminal proteolytic cleavage. These low molecular mass FMR1 proteins did not bind RNA, in contrast with the high molecular mass FMR1 proteins. The significance of these low molecular mass proteins remains to be studied.