Transcriptomic changes in the microsporidia proliferation and host responses in congenitally infected embryos and larvae.

Congenital infection caused by vertical transmission of microsporidia N. bombycis can result in severe economic losses in the silkworm-rearing industry. Whole-transcriptome analyses have revealed non-coding RNAs and their regulatory networks in N. bombycis infected embryos and larvae. However, transcriptomic changes in the microsporidia proliferation and host responses in congenitally infected embryos and larvae remains unclear. Here, we simultaneously compared the transcriptomes of N. bombycis and its host B. mori embryos of 5-day and larvae of 1-, 5- and 10-day during congenital infection. For the transcriptome of N. bombycis, a comparison of parasite expression patterns between congenital-infected embryos and larva showed most genes related to parasite central carbon metabolism were down-regulated in larvae during infection, whereas the majority of genes involved in parasite proliferation and growth were up-regulated. Interestingly, a large number of distinct or shared differentially expressed genes (DEGs) were revealed by the Venn diagram and heat map, many of them were connected to infection related factors such as Ricin B lectin, spore wall protein, polar tube protein, and polysaccharide deacetylase. For the transcriptome of B. mori infected with N. bombycis, beyond numerous DEGs related to DNA replication and repair, mRNA surveillance pathway, RNA transport, protein biosynthesis, and proteolysis, with the progression of infection, a large number of DEGs related to immune and infection pathways, including phagocytosis, apoptosis, TNF, Toll-like receptor, NF-kappa B, Fc epsilon RI, and some diseases, were successively identified. In contrast, most genes associated with the insulin signaling pathway, 2-oxacarboxylic acid metabolism, amino acid biosynthesis, and lipid metabolisms were up-regulated in larvae compared to those in embryos. Furthermore, dozens of distinct and three shared DEGs that were involved in the epigenetic regulations, such as polycomb, histone-lysine-specific demethylases, and histone-lysine-N-methyltransferases, were identified via the Venn diagram and heat maps. Notably, many DEGs of host and parasite associated with lipid-related metabolisms were verified by RT-qPCR. Taken together, simultaneous transcriptomic analyses of both host and parasite genes lead to a better understanding of changes in the microsporidia proliferation and host responses in embryos and larvae in N. bombycis congenital infection.

CRISPR/Cas9-Mediated Knockout of the PxJHBP Gene Resulted in Increased Susceptibility to Bt Cry1Ac Protoxin and Reduced Lifespan and Spawning Rates in Plutella xylostella.

Juvenile hormone binding protein (JHBP) is a key regulator of JH signaling, and crosstalk between JH and 20-hydroxyecdysone (20E) can activate and fine-tune the mitogen-activated protein kinase cascade, leading to resistance to insecticidal proteins from Bacillis thuringiensis (Bt). However, the involvement of JHBP in the Bt Cry1Ac resistance of Plutella xylostella remains unclear. Here, we cloned a full-length cDNA encoding JHBP, and quantitative real-time PCR (qPCR) analysis showed that the expression of the PxJHBP gene in the midgut of the Cry1Ac-susceptible strain was significantly higher than that of the Cry1Ac-resistant strain. Furthermore, CRISPR/Cas9-mediated knockout of the PxJHBP gene significantly increased Cry1Ac susceptibility, resulting in a significantly shorter lifespan and reduced fertility. These results demonstrate that PxJHBP plays a critical role in the resistance to Cry1Ac protoxin and in the regulation of physiological metabolic processes associated with reproduction in adult females, providing valuable insights to improve management strategies of P. xylostella.

Effects of dietary urea supplementation on performance of selected insect species.

Feeding costs of farmed insects may be reduced by applying alternative nitrogen sources such as urea that can partly substitute true proteins. The aim of this study was to examine the effects of different nitrogen sources on body weight (BW) and survival rate (SR) of the Jamaican field cricket (JFC, Gryllus assimilis), the house cricket (HC, Acheta domesticus), yellow mealworm larvae (YM, Tenebrio molitor) and superworm larvae (SW, Zophobas morio). Crickets were either housed individually or in groups, and larvae were group-housed. Six isonitrogenous feeds composed of 3.52% nitrogen were designed for all four insect species using four independent replicates with micellar casein: urea proportions of 100-0%, 75-25%, 50-50%, 25-75%, 0-100% and 100% extracted soybean meal. All selected insect species were able to utilise urea. However, urea as the only nitrogen source resulted in low final BW. In the HC, the JFC, and the YM on nitrogen basis urea can replace 25% of micellar casein without having any negative effects on BW and SR in comparison to the 100% micellar casein group. In the SW, a 25% urea level did not have a significant effect on final BW, but SR decreased significantly.

Molecular-Weight-Dependent Degradation of Plastics: Deciphering Host-Microbiome Synergy Biodegradation of High-Purity Polypropylene Microplastics by Mealworms.

The biodegradation of polypropylene (PP), a highly persistent nonhydrolyzable polymer, by Tenebrio molitor has been confirmed using commercial PP microplastics (MPs) (Mn 26.59 and Mw 187.12 kDa). This confirmation was based on the reduction of the PP mass, change in molecular weight (MW), and a positive Δδ13C in the residual PP. A MW-dependent biodegradation mechanism was investigated using five high-purity PP MPs, classified into low (0.83 and 6.20 kDa), medium (50.40 and 108.0 kDa), and high (575.0 kDa) MW categories to access the impact of MW on the depolymerization pattern and associated gene expression of gut bacteria and the larval host. The larvae can depolymerize/biodegrade PP polymers with high MW although the consumption rate and weight losses increased, and survival rates declined with increasing PP MW. This pattern is similar to observations with polystyrene (PS) and polyethylene (PE), i.e., both Mn and Mw decreased after being fed low MW PP, while Mn and/or Mw increased after high MW PP was fed. The gut microbiota exhibited specific bacteria associations, such as Kluyvera sp. and Pediococcus sp. for high MW PP degradation, Acinetobacter sp. for medium MW PP, and Bacillus sp. alongside three other bacteria for low MW PP metabolism. In the host transcriptome, digestive enzymes and plastic degradation-related bacterial enzymes were up-regulated after feeding on PP depending on different MWs. The T. molitor host exhibited both defensive function and degradation capability during the biodegradation of plastics, with high MW PP showing a relatively negative impact on the larvae.

Key HPI axis receptors facilitate light adaptive behavior in larval zebrafish.

The vertebrate stress response (SR) is mediated by the hypothalamic-pituitary-adrenal (HPA) axis and contributes to generating context appropriate physiological and behavioral changes. Although the HPA axis plays vital roles both in stressful and basal conditions, research has focused on the response under stress. To understand broader roles of the HPA axis in a changing environment, we characterized an adaptive behavior of larval zebrafish during ambient illumination changes. Genetic abrogation of glucocorticoid receptor (nr3c1) decreased basal locomotor activity in light and darkness. Some key HPI axis receptors (mc2r [ACTH receptor], nr3c1), but not nr3c2 (mineralocorticoid receptor), were required to adapt to light more efficiently but became dispensable when longer illumination was provided. Such light adaptation was more efficient in dimmer light. Our findings show that the HPI axis contributes to the SR, facilitating the phasic response and maintaining an adapted basal state, and that certain adaptations occur without HPI axis activity.

JAK/STAT mediated insulin resistance in muscles is essential for effective immune response.

BACKGROUND: The metabolically demanding nature of immune response requires nutrients to be preferentially directed towards the immune system at the expense of peripheral tissues. We study the mechanisms by which this metabolic reprograming occurs using the parasitoid infection of Drosophila larvae. To overcome such an immune challenge hemocytes differentiate into lamellocytes, which encapsulate and melanize the parasitoid egg. Hemocytes acquire the energy for this process by expressing JAK/STAT ligands upd2 and upd3, which activates JAK/STAT signaling in muscles and redirects carbohydrates away from muscles in favor of immune cells. METHODS: Immune response of Drosophila larvae was induced by parasitoid wasp infestation. Carbohydrate levels, larval locomotion and gene expression of key proteins were compared between control and infected animals. Efficacy of lamellocyte production and resistance to wasp infection was observed for RNAi and mutant animals. RESULTS: Absence of upd/JAK/STAT signaling leads to an impaired immune response and increased mortality. We demonstrate how JAK/STAT signaling in muscles leads to suppression of insulin signaling through activation of ImpL2, the inhibitor of Drosophila insulin like peptides. CONCLUSIONS: Our findings reveal cross-talk between immune cells and muscles mediates a metabolic shift, redirecting carbohydrates towards immune cells. We emphasize the crucial function of muscles during immune response and show the benefits of insulin resistance as an adaptive mechanism that is necessary for survival.

CRISPR-Cas9 mediated dsRNase knockout improves RNAi efficiency in the fall armyworm.

Lepidopteran insects are refractory to RNA interference (RNAi) response, especially to orally delivered double-stranded RNA (dsRNA). High nuclease activity in the midgut lumen is proposed as one of the major reasons for RNAi insensitivity. We identified three dsRNase genes highly expressed in the midgut of fall armyworm (FAW), Spodoptera frugiperda. The genomic region harboring those three dsRNase genes was deleted using the CRISPR-Cas9-mediated genome editing method. A homozygous line with deletion of three dsRNase genes was produced. dsRNA degradation by midgut lumen contents of mutant larvae was lower than in wild-type larvae. Feeding dsRNA targeting the inhibitor of apoptosis (IAP) gene increased knockdown of the target gene and mortality in mutants compared to wild-type larvae. These results suggest that dsRNases in the midgut contribute to RNAi inefficiency in FAW. Formulations that protect dsRNA from dsRNase degradation may improve RNAi efficiency in FAW and other lepidopteran insects.

A chromosome-level genome assembly of the soybean pod borer: insights into larval transcriptional response to transgenic soybean expressing the pesticidal Cry1Ac protein.

BACKGROUND: Genetically modified (GM) crop plants with transgenic expression of Bacillus thuringiensis (Bt) pesticidal proteins are used to manage feeding damage by pest insects. The durability of this technology is threatened by the selection for resistance in pest populations. The molecular mechanism(s) involved in insect physiological response or evolution of resistance to Bt is not fully understood. RESULTS: To investigate the response of a susceptible target insect to Bt, the soybean pod borer, Leguminivora glycinivorella (Lepidoptera: Tortricidae), was exposed to soybean, Glycine max, expressing Cry1Ac pesticidal protein or the non-transgenic parental cultivar. Assessment of larval changes in gene expression was facilitated by a third-generation sequenced and scaffolded chromosome-level assembly of the L. glycinivorella genome (657.4 Mb; 27 autosomes + Z chromosome), and subsequent structural annotation of 18,197 RefSeq gene models encoding 23,735 putative mRNA transcripts. Exposure of L. glycinivorella larvae to transgenic Cry1Ac G. max resulted in prediction of significant differential gene expression for 204 gene models (64 up- and 140 down-regulated) and differential splicing among isoforms for 10 genes compared to unexposed cohorts. Differentially expressed genes (DEGs) included putative peritrophic membrane constituents, orthologs of Bt receptor-encoding genes previously linked or associated with Bt resistance, and those involved in stress responses. Putative functional Gene Ontology (GO) annotations assigned to DEGs were significantly enriched for 36 categories at GO level 2, respectively. Most significantly enriched cellular component (CC), biological process (BP), and molecular function (MF) categories corresponded to vacuolar and microbody, transport and metabolic processes, and binding and reductase activities. The DEGs in enriched GO categories were biased for those that were down-regulated (≥ 0.783), with only MF categories GTPase and iron binding activities were bias for up-regulation genes. CONCLUSIONS: This study provides insights into pathways and processes involved larval response to Bt intoxication, which may inform future unbiased investigations into mechanisms of resistance that show no evidence of alteration in midgut receptors.

Molecular characterization of the cytochrome P450 enzyme CYP18A1 in Henosepilachna vigintioctopunctata.

In insects, the expression of 20E response genes that initiate metamorphosis is triggered by a pulse of 20-hydroxyecdysone (20E). The 20E pulse is generated through two processes: synthesis, which increases its level, and inactivation, which decreases its titer. CYP18A1 functions as an ecdysteroid 26-hydroxylase and plays a role in 20E removal in several representative insects. However, applying 20E degradation activity of CYP18A1 to other insects remains a significant challenge. In this study, we discovered high levels of Hvcyp18a1 during the larval and late pupal stages, particularly in the larval epidermis and fat body of Henosepilachna vigintioctopunctata, a damaging Coleopteran pest of potatoes. RNA interference (RNAi) targeting Hvcyp18a1 disrupted the pupation. Approximately 75% of the Hvcyp18a1 RNAi larvae experienced developmental arrest and remained as stunted prepupae. Subsequently, they gradually turned black and eventually died. Among the Hvcyp18a1-depleted animals that successfully pupated, around half became malformed pupae with swollen elytra and hindwings. The emerged adults from these deformed pupae appeared misshapen, with shriveled elytra and hindwings, and were wrapped in the pupal exuviae. Furthermore, RNAi of Hvcyp18a1 increased the expression of a 20E receptor gene (HvEcR) and four 20E response transcripts (HvE75, HvHR3, HvBrC, and HvαFTZ-F1), while decreased the transcription of HvßFTZ-F1. Our findings confirm the vital role of CYP18A1 in the pupation, potentially involved in the degradation of 20E in H. vigintioctopunctata.

Prolonged Heat Stress during Winter Diapause Alters the Expression of Stress-Response Genes in Ostrinia nubilalis (Hbn.).

During diapause, a state of temporarily arrested development, insects require low winter temperatures to suppress their metabolism, conserve energy stores and acquire cold hardiness. A warmer winter could, thus, reduce diapause incidence and duration in many species, prematurely deplete their energy reserves and compromise post-diapause fitness. In this study, we investigated the combined effects of thermal stress and the diapause program on the expression of selected genes involved in antioxidant defense and heat shock response in the European corn borer Ostrinia nubilalis. By using qRT-PCR, it has been shown that response to chronic heat stress is characterized by raised mRNA levels of grx and trx, two important genes of the antioxidant defense system, as well as of hsp70 and, somewhat, of hsp90, two major heat shock response proteins. On the other hand, the expression of hsc70, hsp20.4 and hsp20.1 was discontinuous in the latter part of diapause, or was strongly controlled by the diapause program and refractory to heat stress, as was the case for mtn and fer, genes encoding two metal storage proteins crucial for metal ion homeostasis. This is the first time that the effects of high winter temperatures have been assessed on cold-hardy diapausing larvae and pupae of this important corn pest.

Discovery of Trisubstituted N-Phenylpyrazole Containing Diamides with Improved Insecticidal Activity.

To increase the structural diversity of insecticides and meet the needs of effective integrated insect management, the structure of chlorantraniliprole was modified based on a previously established three-dimensional quantitative structure-activity relationship (3D-QSAR) model. The pyridinyl moiety in the structure of chlorantraniliprole was replaced with a 4-fluorophenyl group. Further modifications of this 4-fluorophenyl group by introducing a halogen atom at position 2 and an electron-withdrawing group (e.g., iodine, cyano, and trifluoromethyl) at position 5 led to 34 compounds with good insecticidal efficacy against Mythimna separata, Plutella xylostella, and Spodoptera frugiperda. Among them, compound IV f against M. separata showed potency comparable to that of chlorantraniliprole. IV p against P. xylostella displayed a 4.5 times higher potency than chlorantraniliprole. In addition, IV d and chlorantraniliprole exhibited comparable potencies against S. frugiperda. Transcriptome analysis showed that the molecular target of compound IV f is the ryanodine receptor. Molecular docking was further performed to verify the mode of action and insecticidal activity against resistant P. xylostella.

Immunological regulation by Toll-1 and Spätzle-4 in larval density-dependent prophylaxis of the oriental armyworm, Mythimna separata.

High population density has been shown to alter insect prophylactic immunity. Toll-Spätzle pathway performs a key function in insect innate immune response. To determine the role of Toll and Spätzle, two main components of Toll-Spätzle pathway, in the density-dependent prophylaxis of Mythimna separata. We identified full-length cDNA encoding the Toll-1 and Spätzle-4 genes in M. separata (designed MsToll-1 and Ms Spätzle-4). Both MsToll-1 and MsSpätzle-4 were expressed throughout all developmental stages. MsToll-1 expression was highly in fat body and brain and MsSpätzle-4 was highly expressed in brain and Malpighian tubule. With increased larval density, MsToll-1 expression was markedly up-regulated. MsSpätzle-4 expression was found to be raised in larvae that were fed in high density (5 and 10 larvae per jar). Co-immunoprecipitation assays demonstrated that MsToll-1 interacted with MsSpätzle-4. Immune-related genes transcriptions were considerably reduced in high-density larvae MsToll-1 (or MsSpätzle-4) was silenced by dsRNA injection. Meanwhile, a discernible reduction in the survival rate of the larvae exposed to Bacillus thuringiensis infection with silence of MsToll-1 (or MsSpätzle-4) was observed. This study implies that prophylactic immunity was influenced by crowded larvae via modulating the Toll-Spätzle pathway in M. separata and allow for a new understanding of into density-dependent prophylaxis in insects.

Understanding the toxicity mechanism of gelsemine in zebrafish.

Gelsemium elegans (GE), also known as Duanchangcao, is a plant associated with toxic symptoms related to the abdomen; however, the toxicity caused by GE remains unknown. Gelsemine (GEL) is an alkaloid extracted from GE and is one of the most toxic alkaloids. This study used zebrafish as an animal model and employed high-throughput gene sequencing to identify genes and signaling pathways related to GEL toxicity. Exposure to GEL negatively impacted heart rate, swim bladder development, and activity in zebrafish larvae. Transcriptomics data revealed the enrichment of inflammatory and phagocyte signaling pathways. RT-PCR analysis revealed a decrease in the expression of pancreas-related genes, including the pancreatic coagulation protease (Ctr) family, such as Ctrl, Ctrb 1, and Ctrc, due to GEL exposure. Furthermore, GEL exposure significantly reduced Ctrb1 protein expression while elevating trypsin and serum amylase activities in zebrafish larvae. GEL also resulted in a decrease in pancreas-associated fluorescence area and an increase in neutrophil-related fluorescence area in transgenic zebrafish. This study revealed that GEL toxicity in zebrafish larvae is related to acute pancreatic inflammation.

Investigating the toxic mechanism of iron oxide nanoparticles-induced oxidative stress in tadpole (Duttaphrynus melanostictus): A combined biochemical and molecular study.

Metal oxide nanomaterials have toxicity towards aquatic organisms, especially microbes and invertebrates, but little is known about their impact on amphibians. We conducted a study on Duttaphrynus melanostictus (D. melanostictus) tadpoles to explore the chronic toxicity effects of iron oxide nanoparticles (IONPs) and the underlying mechanisms of IONPs-induced oxidative stress. IONPs exposure led to increased iron accumulation in the blood, liver, and kidneys of tadpoles, significantly affecting blood parameters and morphology. Higher IONPs concentrations (10 and 50 mg L-1) triggered reactive oxygen species generation, resulting in lipid peroxidation, oxidative stress, and pronounced toxicity in tadpoles. The activity levels of antioxidant enzymes/proteins (SOD, CAT, albumin, and lysozyme) decreased after IONPs exposure, and immunological measures in the blood serum were significantly reduced compared to the control group. Molecular docking analysis revealed that IONPs primarily attached to the surface of SOD/CAT/albumin/lysozyme through hydrogen bonding and hydrophobic forces. Overall, this study emphasizes the ability of IONPs to induce oxidative damage by decreasing immunological profiles such as ACH50 (34.58 ± 2.74 U mL-1), lysozyme (6.94 ± 0.82 U mL-1), total Ig (5.00 ± 0.35 g dL-1), total protein (1.20 ± 0.17 g dL-1), albumin (0.52 ± 0.01 g dL-1) and globulin (0.96 ± 0.01 g dL-1) and sheds light on their potential toxic effects on tadpoles.

Determination of the larval precursor configuration of the Drosophila adult hindgut by G-TRACE analysis.

The Drosophila hindgut is a classical model to study organogenesis. The adult hindgut originates from the precursor cells in the larval hindgut. However, the territory of these cells has still not been well determined. A ring of wingless (wg)-expressing cells lies at the anterior zone of both the larval and adult hindgut. The larval Wg ring was thought as a portion of precursor of the adult hindgut. By applying a cell lineage tracing tool (G-TRACE), we demonstrate that larval wg-expressing cells have no cell lineage contribution to the adult hindgut. Additionally, adult Wg ring cells do not divide and move posteriorly to replenish the hindgut tissue. Instead, we determine that the precursors of the adult pylorus and ileum are situated in the cubitus interruptus (ci)-expressing cells in the anterior zone, and deduce that the precursor stem cells of the adult rectum locate in the trunk region of the larval pylorus including hedgehog (hh)-expressing cells. Together, this research advances our understanding of cell lineage origins and the development of the Drosophila hindgut.

MicroRNA miR-7-5p targets MARK2 to control metamorphosis in Galeruca daurica.

The MARK2 gene, coding microtubule affinity-regulating kinase or serine/threonine protein kinase, is an important modulator in organism microtubule generation and cell polarity. However, its role in the metamorphosis of insects remains unknown. In this study, we found a conserved miRNA, miR-7-5p, which targets MARK2 to participate in the regulation of the larval-pupal metamorphosis in Galeruca daurica. The dual luciferase reporter assay showed that miR-7-5p interacted with the 3' UTR of MARK2 and repressed its expression. The expression profiling of miR-7-5p and MARK2 displayed an opposite trend during the larval-adult development process. In in-vivo experiments, overexpression of miR-7-5p by injecting miR-7-5p agomir in the final instar larvae down-regulated MARK2 and up-regulated main ecdysone signaling pathway genes including E74, E75, ECR, FTZ-F1 and HR3, which was similar to the results from knockdown of MARK2 by RNAi. In contrast, repression of miR-7-5p by injecting miR-7-5p antagomir obtained opposite effects. Notably, both overexpression and repression of miR-7-5p in the final instar larvae caused abnormal molting and high mortality during the larval-pupal transition, and high mortality during the pupal-adult transition. The 20-hydroxyecdysone (20E) injection experiment showed that 20E up-regulated miR-7-5p whereas down-regulated MARK2. This study reveals that the accurate regulation of miRNAs and their target genes is indispensable for insect metamorphosis.

A new insight into Cd exposure-induced hemocyte reduction in Lymantria dispar larvae: Involvement of the ROS-ATF6-ER stress-apoptosis pathway.

Hemocytes are important targets for heavy metal-induced immunotoxicity in insects. This study aimed to investigate the mechanism by which cadmium (Cd) exposure affects the hemocyte count in Lymantria dispar larvae. The results showed that the number of larval hemocytes was significantly decreased under Cd exposure, accompanied by a significant increase in the apoptosis rate and the expression of Caspase-3. The endoplasmic reticulum (ER) of hemocytes in the Cd-treated group showed irregular swelling. Expression levels of ER stress indicator genes (CHOP, Bip1, Bip2, Bip3, and Bip4) were significantly higher in the Cd-treated group. Among the three pathways that potentially mediate ER stress, only the key genes in the ATF6 pathway (ATF6, S1P-1, S1P-2, and WFS1) exhibited differential responses to Cd exposure. Cd exposure significantly increased the levels of reactive oxygen species (ROS) and the expression of oxidative stress-related genes (CNCC, P38, and ATF2) in hemocytes. Studies using inhibitors confirmed that apoptosis mediated the decrease in hemocyte count, ER stress mediated apoptosis, ATF6 pathway mediated ER stress, and ROS or oxidative stress mediated ER stress through the activation of the ATF6 pathway. Taken together, the ROS-ATF6-ER stress-apoptosis pathway is responsible for the reduction in the hemocyte count of Cd-treated L. dispar larvae.

A sodium-dependent trehalose transporter contributes to anhydrobiosis in insect cell line, Pv11.

Pv11 is the only animal cell line that, when preconditioned with a high concentration of trehalose, can be preserved in the dry state at room temperature for more than one year while retaining the ability to resume proliferation. This extreme desiccation tolerance is referred to as anhydrobiosis. Here, we identified a transporter that contributes to the recovery of Pv11 cells from anhydrobiosis. In general, the solute carrier 5 (SLC5)-type secondary active transporters cotransport Na+ and carbohydrates including glucose. The heterologous expression systems showed that the transporter belonging to the SLC5 family, whose expression increases upon rehydration, exhibits Na+-dependent trehalose transport activity. Therefore, we named it STRT1 (sodium-ion trehalose transporter 1). We report an SLC5 family member that transports a naturally occurring disaccharide, such as trehalose. Knockout of the Strt1 gene significantly reduced the viability of Pv11 cells upon rehydration after desiccation. During rehydration, when intracellular trehalose is no longer needed, Strt1-knockout cells released the disaccharide more slowly than the parental cell line. During rehydration, Pv11 cells became roughly spherical due to osmotic pressure changes, but then returned to their original spindle shape after about 30 min. Strt1-knockout cells, however, required about 50 min to adopt their normal morphology. STRT1 probably regulates intracellular osmolality by releasing unwanted intracellular trehalose with Na+, thereby facilitating the recovery of normal cell morphology during rehydration. STRT1 likely improves the viability of dried Pv11 cells by rapidly alleviating the significant physical stresses that arise during rehydration.

Biotransformation of Pb and As from sewage sludge and food waste by black soldier fly larvae: Migration mechanism of bacterial community and metalloregulatory protein scales.

The accumulation and transformation of lead (Pb) and arsenic (As) during the digestion of sewage sludge (SS) by black soldier fly larvae (BSFL) remain unclear. In this study, we used 16 s rRNA and metagenomic sequencing techniques to investigate the correlation between the microbial community, metalloregulatory proteins (MRPs), and Pb and As migration and transformation. During the 15-day test period, BSFL were able to absorb 34-48 % of Pb and 32-45 % of As into their body. Changes in bacterial community abundance, upregulation of MRPs, and redundancy analysis (RDA) results confirmed that ZntA, EfeO, CadC, ArsR, ArsB, ArsD, and ArsA play major roles in the adsorption and stabilization of Pb and As, which is mainly due to the high contribution rates of Lactobacillus (48-59 %) and Enterococcus (21-23 %). Owing to the redox reaction, the regulation of the MRPs, and the change in pH, the Pb and As in the BSFL residue were mainly the residual fraction (F4). The RDA results showed that Lactobacillus and L.koreensis could significantly (P < 0.01) reduce the reducible fraction (F2) and F4 of Pb, whereas Firmicutes and L.fermentum can significantly (P < 0.05) promote the transformation of As to F4, thus realizing the passivation Pb and As. This study contributes to the understanding of Pb and As in SS adsorbed by BSFL and provides important insights into the factors that arise during the BSFL-mediated migration of Pb and As.

Go local: Enhancing sustainable production of Tenebrio molitor through valorization of locally available agricultural byproducts.

Insects receive increasing attention as an alternative source of protein for animals and humans, and thus, the production of low-cost insects for meeting the dietary demand on sustained basis is an ever-growing concept. This study aims to design dietswith locally available agricultural byproducts from Greece as feed for larvae of the yellow mealworm, Tenebrio molitor L. (Coleoptera: Tenebrionidae). This will considerably reduce the cost of insect feed and the environmental impact of insect farming by using locally available agricultural byproducts as economic insect feedstock. More specifically, five agricultural byproducts derived from the production of cereals and legumes were utilized to design twelve different diets at two protein levels, i.e., 17.4 and 22.5% protein content. All diets were evaluated both at laboratory scale, but also at pilot scale. Based on the obtained results, both bioassays revealed that the diets contained one legume and one cereal byproduct (i.e., lupin and triticale as well as lupin and oat) supported more efficiently the growth and performance of the larvae, irrespective of the protein level. Indicatively, individual larval weight of the best performed larvae from both groups ranged from 132 to 142 mg. Moreover, our results highlight the fact that data derived from laboratory scale bioassays are not always easy to be extrapolated to industrial production. For instance, the total harvest of larvae, a parameter assessed in the tray scale bioassay, exhibited a disparity between diet A2 (910 g) and diet A3 (749 g), despite both being deemed optimal in the laboratory-scale experiment. Our study aims to promote a circular approach for the industrial rearing of insects through integration of local agricultural byproducts into specific diets for T. molitor larvae.