Benzaldehyde acts as a behaviorally active component in brewer's yeast protein powder which attracts B. dorsalis through olfaction.

The Oriental fruit fly, Bactrocera dorsalis, is a significant pest that damages a variety of fruit crops. The effectiveness of chemical pesticides against such pests is limited, raising concerns about pesticide residues and resistance. Proteins naturally attract B. dorsalis and have led to the development of a management strategy known as protein bait attractant technology (BAT). Although the attraction of protein sources to B. dorsalis is well-documented, the biologically active components within these sources are not fully understood. This study employed analytical chemistry, behavioral tests, and electrophysiological techniques to investigate the behaviorally active components of beer yeast protein powder (BYPD), aiming to provide a basis for improving and developing protein baits. An olfactory trap assay confirmed the attractiveness of BYPD, and five components with high abundance were identified from its headspace volatiles using GC-MS. These components included ethanol, isoamyl alcohol, ethyl decanoate, benzaldehyde, and phenylethyl alcohol. Mixtures of these five components demonstrated significant attraction to B. dorsalis adults, with benzaldehyde identified as a potential key component. The attractiveness of benzaldehyde required a relatively large dose, and it was most attractive to adults that had been starved from dusk until the following morning. Attraction of adult flies to benzaldehyde appeared mainly mediated by inputs from olfactory receptors. While EAG data supports that ionotropic receptors could influence the detection of benzaldehyde in female adults, they did not affect female behavior towards benzaldehyde. These findings indicate that benzaldehyde is an important behaviorally active component in BYPD and offer insights for developing novel protein lures to control B. dorsalis in an environmentally friendly manner.

Human surfactant protein A inhibits SARS-CoV-2 infectivity and alleviates lung injury in a mouse infection model.

Introduction: SARS coronavirus 2 (SARS-CoV-2) infects human angiotensin-converting enzyme 2 (hACE2)-expressing lung epithelial cells through its spike (S) protein. The S protein is highly glycosylated and could be a target for lectins. Surfactant protein A (SP-A) is a collagen-containing C-type lectin, expressed by mucosal epithelial cells and mediates its antiviral activities by binding to viral glycoproteins. Objective: This study examined the mechanistic role of human SP-A in SARS-CoV-2 infectivity and lung injury in vitro and in vivo. Results: Human SP-A can bind both SARS-CoV-2 S protein and hACE2 in a dose-dependent manner (p<0.01). Pre-incubation of SARS-CoV-2 (Delta) with human SP-A inhibited virus binding and entry and reduced viral load in human lung epithelial cells, evidenced by the dose-dependent decrease in viral RNA, nucleocapsid protein (NP), and titer (p<0.01). We observed significant weight loss, increased viral burden, and mortality rate, and more severe lung injury in SARS-CoV-2 infected hACE2/SP-A KO mice (SP-A deficient mice with hACE2 transgene) compared to infected hACE2/mSP-A (K18) and hACE2/hSP-A1 (6A2) mice (with both hACE2 and human SP-A1 transgenes) 6 Days Post-infection (DPI). Furthermore, increased SP-A level was observed in the saliva of COVID-19 patients compared to healthy controls (p<0.05), but severe COVID-19 patients had relatively lower SP-A levels than moderate COVID-19 patients (p<0.05). Discussion: Collectively, human SP-A attenuates SARS-CoV-2-induced acute lung injury (ALI) by directly binding to the S protein and hACE2, and inhibiting its infectivity; and SP-A level in the saliva of COVID-19 patients might serve as a biomarker for COVID-19 severity.

Odorant Receptor BdorOR49b Mediates Oviposition and Attraction Behavior of Bactrocera dorsalis to Benzothiazole.

The ability to recognize a host plant is crucial for insects to meet their nutritional needs and locate suitable sites for laying eggs. Bactrocera dorsalis is a highly destructive pest in fruit crops. Benzothiazole has been found to induce oviposition behavior in the gravid B. dorsalis. However, the ecological roles and the olfactory receptor responsible for benzothiazole are not yet fully understood. In this study, we found that adults were attracted to benzothiazole, which was an effective oviposition stimulant. In vitro experiments showed that BdorOR49b was narrowly tuned to benzothiazole. The electroantennogram results showed that knocking out BdorOR49b significantly reduced the antennal electrophysiological response to benzothiazole. Compared with wild-type flies, the attractiveness of benzothiazole to BdorOR49b knockout adult was significantly attenuated, and mutant females exhibited a severe decrease in oviposition behavior. Altogether, our work provides valuable insights into chemical communications and potential strategies for the control of this pest.

Organized assembly of chitosan into mechanically strong bio-composite by introducing a recombinant insect structural protein OfCPH-1.

Chitosan, known for its appealing biological properties in packaging and biomedical applications, faces challenges in achieving a well-organized crystalline structure for mechanical excellence under mild conditions. Herein, we propose a facile and mild bioengineering approach to induce organized assembly of amorphous chitosan into mechanically strong bio-composite via incorporating a genetically engineered insect structural protein, the cuticular protein hypothetical-1 from the Ostrinia furnacalis (OfCPH-1). OfCPH-1 exhibits high binding affinity to chitosan via hydrogen-bonding interactions. Simply mixing a small proportion (0.5 w/w%) of bioengineered OfCPH-1 protein with acidic chitosan precursor induces the amorphous chitosan chains to form fibrous networks with hydrated chitosan crystals, accompanied with a solution-to-gel transition. We deduce that the water shell destruction driven by strong protein-chitosan interactions, triggers the formation of well-organized crystalline chitosan, which therefore offers the chitosan with significantly enhanced swelling resistance, and strength and modulus that outperforms that of most reported chitosan-based materials as well as petroleum-based plastics. Moreover, the composite exhibits a stretch-strengthening behavior similar to the training living muscles on cyclic load. Our work provides a route for harnessing the OfCPH-1-chitosan interaction in order to form a high-performance, sustainably sourced bio-composite.

Two sex pheromone receptors for sexual communication in the American cockroach.

Volatile sex pheromones are vital for sexual communication between males and females. Females of the American cockroach, Periplaneta americana, produce and emit two sex pheromone components, periplanone-A (PA) and periplanone-B (PB). Although PB is the major sex attractant and can attract males, how it interacts with PA in regulating sexual behaviors is still unknown. In this study, we found that in male cockroaches, PA counteracted PB attraction. We identified two odorant receptors (ORs), OR53 and OR100, as PB/PA and PA receptors, respectively. OR53 and OR100 were predominantly expressed in the antennae of sexually mature males, and their expression levels were regulated by the sex differentiation pathway and nutrition-responsive signals. Cellular localization of OR53 and OR100 in male antennae further revealed that two types of sensilla coordinate a complex two-pheromone-two-receptor pathway in regulating cockroach sexual behaviors. These findings indicate distinct functions of the two sex pheromone components, identify their receptors and possible regulatory mechanisms underlying the male-specific and age-dependent sexual behaviors, and can guide novel strategies for pest management.

Insect cuticle-inspired design of sustainably sourced composite bioplastics with enhanced strength, toughness and stretch-strengthening behavior.

Insect cuticles that are mainly made of chitin, chitosan and proteins provide insects with rigid, stretchable and robust skins to defend harsh external environment. The insect cuticle therefore provides inspiration for engineering biomaterials with outstanding mechanical properties but also sustainability and biocompatibility. We herein propose a design of high-performance and sustainable bioplastics via introducing CPAP3-A1, a major structural protein in insect cuticles, to specifically bind to chitosan. Simply mixing 10w/w% bioengineered CPAP3-A1 protein with chitosan enables the formation of plastics-like, sustainably sourced chitosan/CPAP3-A1 composites with significantly enhanced strength (∼90 MPa) and toughness (∼20 MJ m -3), outperforming previous chitosan-based composites and most synthetic petroleum-based plastics. Remarkably, these bioplastics exhibit a stretch-strengthening behavior similar to the training living muscles. Mechanistic investigation reveals that the introduction of CPAP3-A1 induce chitosan chains to assemble into a more coarsened fibrous network with increased crystallinity and reinforcement effect, but also enable energy dissipation via reversible chitosan-protein interactions. Further uniaxial stretch facilitates network re-orientation and increases chitosan crystallinity and mechanical anisotropy, thereby resulting in stretch-strengthening behavior. In general, this study provides an insect-cuticle inspired design of high-performance bioplastics that may serve as sustainable and bio-friendly materials for a wide range of engineering and biomedical application potentials.

An odorant receptor mediates the avoidance of Plutella xylostella against parasitoid.

BACKGROUND: Ecosystems are brimming with myriad compounds, including some at very low concentrations that are indispensable for insect survival and reproduction. Screening strategies for identifying active compounds are typically based on bioassay-guided approaches. RESULTS: Here, we selected two candidate odorant receptors from a major pest of cruciferous plants-the diamondback moth Plutella xylostella-as targets to screen for active semiochemicals. One of these ORs, PxylOR16, exhibited a specific, sensitive response to heptanal, with both larvae and adult P. xylostella displaying heptanal avoidance behavior. Gene knockout studies based on CRISPR/Cas9 experimentally confirmed that PxylOR16 mediates this avoidance. Intriguingly, rather than being involved in P. xylostella-host plant interaction, we discovered that P. xylostella recognizes heptanal from the cuticular volatiles of the parasitoid wasp Cotesia vestalis, possibly to avoid parasitization. CONCLUSIONS: Our study thus showcases how the deorphanization of odorant receptors can drive discoveries about their complex functions in mediating insect survival. We also demonstrate that the use of odorant receptors as a screening platform could be efficient in identifying new behavioral regulators for application in pest management.

Identification of the murine osteoblastic cell MC3T3-E1 as a permissive cell line in response to lumpy skin disease virus.

Lumpy skin disease virus (LSDV) is a rapidly emerging pathogen in China. Screening suitable cells for LSDV replication is vital for future research on pathogenic mechanisms and vaccine development. Previous comparative studies have identified that the rodent-derived BHK21 is a highly susceptible cell model to LSDV infection. Using western blot, indirect immune-fluorescence assay, flow cytometry, and transmission electron microscopy methods, this study is the first to identify the murine osteoblastic cell line MC3T3-E1 as a novel permissive cell model for LSDV infection. The establishment of MC3T3-E1 as a suitable infectious cell model enhances our understanding of the species range and cell types of the permissive cells and nonpermissive that support LSDV replication. It is helpful to accelerate future research on the pathogenesis, clinical application, and vaccine development of LSDV.

Comparative transcriptome analysis of the antenna and proboscis reveals feeding state-dependent chemosensory genes in Eupeodes corollae.

The physiological state of an insect can affect its olfactory system. However, the molecular mechanism underlying the effect of nutrition-dependent states on odour-guided behaviours in hoverflies remains unclear. In this study, comparative transcriptome analysis of the antenna and proboscis from Eupeodes corollae under different feeding states was conducted. Compared with the previously published antennal transcriptome, a total of 32 novel chemosensory genes were identified, including 4 ionotropic receptors, 17 gustatory receptors, 9 odorant binding proteins and 2 chemosensory proteins. Analysis of differences in gene expression between different feeding states in male and female antennae and proboscises revealed that the expression levels of chemosensory genes were impacted by feeding state. For instance, the expression levels of EcorOBP19 in female antennae, EcorOBP6 in female proboscis, and EcorOR6, EcorOR14, EcorIR5 and EcorIR84a in male antennae were significantly upregulated after feeding. On the other hand, the expression levels of EcorCSP7 in male proboscis and EcorOR40 in male antennae were significantly downregulated. These findings suggest that nutritional state plays a role in the adaptation of hoverflies' olfactory system to food availability. Overall, our study provides important insights into the plasticity and adaptation of chemosensory systems in hoverflies.

A female-specific odorant receptor mediates oviposition deterrence in the moth Helicoverpa armigera.

Finding ideal oviposition sites is a task of vital importance for all female insects. To ensure optimal conditions for their progeny, females of herbivorous insects detect not only the odors of a relevant host plant but also chemicals released by eggs, named oviposition-deterring pheromones (ODPs). It is reported that such chemicals play critical roles in suppressing female oviposition behavior; however, the molecular mechanism underlying the detection of egg-derived ODPs remains elusive. Here, we have identified three specific fatty acid methyl esters from the surface of eggs of Helicoverpa armigera serving as ODPs-methyl oleate (C18:1ME), methyl palmitate (C16:0ME), and methyl stearate (C18:0ME). We demonstrated that these ODPs are detected by the receptor, HarmOR56, exclusively expressed in sensilla trichodea on female antennae. To assess the significance of this receptor, we disrupted HarmOR56 in H. armigera using CRISPR-Cas9 and found that mutant females did not respond to the ODPs, neither in behavioral nor in electrophysiological tests. We therefore conclude that HarmOR56 is indispensable for identifying the ODPs. This study explores, for the first time, how a female-specific odorant receptor detects chemicals from conspecific eggs. Our data elucidate the intriguing biological phenomenon of repulsion to conspecific eggs during oviposition and contribute new insight into a female-specific olfactory pathway linked to reproduction.

Characterization of the pheromone receptors in Mythimna loreyi reveals the differentiation of sex pheromone recognition in Mythimna species.

Pheromone receptors (PRs) are key proteins in the molecular mechanism of pheromone recognition, and exploring the functional differentiation of PRs between closely related species helps to understand the evolution of moth mating systems. Pheromone components of the agricultural pest Mythimna loreyi have turned into (Z)-9-tetradecen-1-yl acetate (Z9-14:OAc), (Z)-7-dodecen-1-yl acetate (Z7-12:OAc), and (Z)-11-hexadecen-1-yl acetate, while the composition differs from that of M. separata in the genus Mythimna. To understand the molecular mechanism of pheromone recognition, we sequenced and analyzed antennal transcriptomes to identify 62 odorant receptor (OR) genes. The expression levels of all putative ORs were analyzed using differentially expressed gene analysis. Six candidate PRs were quantified and functionally characterized in the Xenopus oocytes system. MlorPR6 and MlorPR3 were determined to be the receptors of major and minor components Z9-14:OAc and Z7-12:OAc. MlorPR1 and female antennae (FA)-biased MlorPR5 both possessed the ability to detect pheromones of sympatric species, including (Z,E)-9,12-tetradecadien-1-ol, (Z)-9-tetradecen-1-ol, and (Z)-9-tetradecenal. Based on the comparison of PR functions between M. loreyi and M. separata, we analyzed the differentiation of pheromone recognition mechanisms during the evolution of the mating systems of 2 Mythimna species.

Identification of an odorant receptor responding to sex pheromones in Spodoptera frugiperda extends the novel type-I PR lineage in moths.

In moths, pheromone receptors (PRs) are crucial for intraspecific sexual communication between males and females. Moth PRs are considered as an ideal model for studying the evolution of insect PRs, and a large number of PRs have been identified and functionally characterized in different moth species. Moth PRs were initially thought to fall into a single monophyletic clade in the odorant receptor (OR) family, but recent studies have shown that ORs in another lineage also bind type-I sex pheromones, which indicates that type-I PRs have multiple independent origins in the Lepidoptera. In this study, we investigated whether ORs of the pest moth Spodoptera frugiperda belonging to clades closely related to this novel PR lineage may also have the capacity to bind type-I pheromones and serve as male PRs. Among the 7 ORs tested, only 1 (SfruOR23) exhibited a male-biased expression pattern. Importantly, in vitro functional characterization showed that SfruOR23 could bind several type-I sex pheromone compounds with Z-9-tetradecenal (Z9-14:Ald), a minor component found in female sex pheromone glands, as the optimal ligand. In addition, SfruOR23 also showed weak responses to plant volatile organic compounds. Altogether, we characterized an S. frugiperda PR positioned in a lineage closely related to the novel PR clade, indicating that the type-I PR lineage can be extended in moths.

A classic screening marker does not affect antennal electrophysiology but strongly regulates reproductive behaviours in Bactrocera dorsalis.

The key phenotype white eye (white) has been used for decades to selectively remove females before release in sterile insect technique programs and as an effective screening marker in genetic engineering. Bactrocera dorsalis is a representative tephritid pest causing damage to more than 150 fruit crops. Yet, the function of white in important biological processes remains unclear in B. dorsalis. In this study, the impacts of the white gene on electrophysiology and reproductive behaviour in B. dorsalis were tested. The results indicated that knocking out Bdwhite disrupted eye pigmentation in adults, consistent with previous reports. Bdwhite did not affect the antennal electrophysiology response to 63 chemical components with various structures. However, reproductive behaviours in both males and females were significantly reduced in Bdwhite-/- . Both pre-copulatory and copulation behaviours were significantly reduced in Bdwhite-/- , and the effect was male-specific. Mutant females significantly delayed their oviposition towards γ-octalactone, and the peak of oviposition behaviour towards orange juice was lost. These results show that Bdwhite might not be an ideal screening marker in functional gene research aiming to identify molecular targets for behaviour-modifying chemicals. Instead, owing to its strong effect on B. dorsalis sexual behaviours, the downstream genes regulated by Bdwhite or the genes from white-linked areas could be alternate molecular targets that promote the development of better behavioural modifying chemical-based pest management techniques.

LIRAGLUTIDE ALLEVIATES ACUTE LUNG INJURY AND MORTALITY IN PNEUMONIA-INDUCED SEPSIS THROUGH REGULATING SURFACTANT PROTEIN EXPRESSION AND SECRETION.

ABSTRACT: Glucagon-like peptide 1 (GLP-1) analogs are used to treat type 2 diabetes, and they can regulate insulin secretion, energy homeostasis, inflammation, and immune cell function. This study sought to determine whether the GLP-1 analog liraglutide exerts a beneficial action in an acute lung injury model of pneumonia-induced sepsis. Methods: Wild-type FVB/NJ mice (n = 114) were infected by intratracheal injection with Pseudomonas aeruginosa Xen5 (4 × 10 4 CFU/mouse) or an equal volume (50 µL) of saline (control) with or without a subcutaneous injection of liraglutide (2 mg/kg, 30 min after infection). Mice were killed 24 h after infection. Lung tissues and BALF were analyzed. In separate experiments, the dynamic growth of bacteria and animal mortality was monitored using in vivo imaging system within 48 h after infection. In addition, primary lung alveolar type II cells isolated from mice were used to study the mechanism of liraglutide action. Result: Liraglutide improved survival ( P < 0.05), decreased bacterial loads in vivo , and reduced lung injury scores ( P < 0.01) in septic mice. Liraglutide-treated mice showed decreased levels of inflammatory cells ( P < 0.01) and proinflammatory cytokines (TNF-α and IL-6) ( P < 0.01) in the lung compared with septic controls. Liraglutide significantly increased pulmonary surfactant proteins (SP-A and SP-B) expression/secretion ( P < 0.01) and phospholipid secretion ( P < 0.01) in vivo . Primary alveolar type II cells pretreated with liraglutide improved SP-A and SP-B expression after LPS exposure ( P < 0.01). Conclusion: Liraglutide attenuates mortality and lung inflammation/injury in pneumonia-induced sepsis. The increased surfactant expression/secretion and anti-inflammatory effects of liraglutide represent potential mechanisms by GLP-1 agonists potentiate host defense and maintain alveolar respiratory function in acute lung injury.

Odorant detection in a locust exhibits unusually low redundancy.

Olfactory coding, from insects to humans, is canonically considered to involve considerable across-fiber coding already at the peripheral level, thereby allowing recognition of vast numbers of odor compounds. We show that the migratory locust has evolved an alternative strategy built on highly specific odorant receptors feeding into a complex primary processing center in the brain. By collecting odors from food and different life stages of the locust, we identified 205 ecologically relevant odorants, which we used to deorphanize 48 locust olfactory receptors via ectopic expression in Drosophila. Contrary to the often broadly tuned olfactory receptors of other insects, almost all locust receptors were found to be narrowly tuned to one or very few ligands. Knocking out a single receptor using CRISPR abolished physiological and behavioral responses to the corresponding ligand. We conclude that the locust olfactory system, with most olfactory receptors being narrowly tuned, differs from the so-far described olfactory systems.

Mutagenesis of Odorant Receptor Coreceptor Orco Reveals the Odorant-Detected Behavior of the Predator Eupeodes corollae.

The successful mating of the hoverfly and the search for prey aphids are of great significance for biological control and are usually mediated by chemical cues. The odorant receptor co-receptor (Orco) genes play a crucial role in the process of insect odor perception. However, the function of Orco in the mating and prey-seeking behaviors of the hoverfly remains relatively unexplored. In this study, we characterized the Orco gene from the hoverfly, Eupeodes corollae, a natural enemy insect. We used the CRISPR/Cas9 technique to knock out the Orco gene of E. corollae, and the EcorOrco-/- homozygous mutant was verified by the genotype analysis. Fluorescence in situ hybridization showed that the antennal ORN of EcorOrco-/- mutant lack Orco staining. Electroantennogram (EAG) results showed that the adult mutant almost lost the electrophysiological response to 15 odorants from three types. The two-way choice assay and the glass Y-tube olfactometer indicated that both the larvae and adults of hoverflies lost their behavioral preference to the aphid alarm pheromone (E)-ß-farnesene (EBF). In addition, the mating assay results showed a significant decrease in the mating rate of males following the knock out of the EcorOrco gene. Although the mating of females was not affected, the amount of eggs being laid and the hatching rate of the eggs were significantly reduced. These results indicated that the EcorOrco gene was not only involved in the detection of semiochemicals in hoverflies but also plays a pivotal role in the development of eggs. In conclusion, our results expand the comprehension of the chemoreceptive mechanisms in the hoverflies and offers valuable insights for the advancement of more sophisticated pest management strategies.

Odorant receptor orthologues from moths display conserved responses to cis-jasmone.

In insects, the odorant receptor (OR) multigene family evolves by the birth-and-death evolutionary model, according to which the OR repertoire of each species has undergone specific gene gains and losses depending on their chemical environment, resulting in taxon-specific OR lineage radiations with different sizes in the phylogenetic trees. Despite the general divergence in the gene family across different insect orders, the ORs in moths seem to be genetically conserved across species, clustered into 23 major clades containing multiple orthologous groups with single-copy gene from each species. We hypothesized that ORs in these orthologous groups are tuned to ecologically important compounds and functionally conserved. cis-Jasmone is one of the compounds that not only primes the plant defense of neighboring receiver plants, but also functions as a behavior regulator to various insects. To test our hypothesis, using Xenopus oocyte recordings, we functionally assayed the orthologues of BmorOR56, which has been characterized as a specific receptor for cis-jasmone. Our results showed highly conserved response specificity of the BmorOR56 orthologues, with all receptors within this group exclusively responding to cis-jasmone. This is supported by the dN/dS analysis, showing that strong purifying selection is acting on this group. Moreover, molecular docking showed that the ligand binding pockets of BmorOR56 orthologues to cis-jasmone are similar. Taken together, our results suggest the high conservation of OR for ecologically important compounds across Heterocera.

In vitro activity of tubercidin against Mycobacterium tuberculosis and nontuberculosis Mycobacteria.

Tubercidin is an adenosine analogue that has been shown to exhibit good activity against some tumours and parasites. In this study, the in vitro activity of tubercidin was evaluated against Mycobacterium tuberculosis (Mtb) and nontuberculosis Mycobacteria (NTM). For determining the MICs of tubercidin, 23 fully drug-sensitive (DS) Mtb strains, 33 multi-drug resistance tuberculosis (MDR-TB) strains, 29 pre-extensively drug-resistant tuberculosis (pre-XDR-TB) strains, 21 extensively drug-resistant tuberculosis (XDR-TB) strains, 17 rapidly growing mycobacteria (RGM) and nine slowly growing mycobacteria (SGM) references strains were tested by microplate-based Alamar Blue assay (MABA) method. The results indicate that tubercidin has high in vitro activity against some drug-resistance Mtb strains and NTM reference strains, which warrants further investigation on the actions of tubercidin and its derivatives as potential drugs for mycobacterial infections.

MFS Transporter Bdorwp Does Not Affect Antennal Electrophysiology but Regulates Reproductive Behaviors in Bactrocera dorsalis.

Developing behavioral modifying chemicals through molecular targets is a promising way to improve semiochemical-based technology for pest management. Identifying molecular targets that affect insect behavior largely relies on functional genetic techniques such as deletions, insertions, and substitutions. Selectable markers have thus been developed to increase the efficiency of screening for successful editing events. However, the effect of selectable markers on relevant phenotypic traits needs to be considered. In this study, we cloned the wp gene ofBactrocera dorsalis. Knocking out Bdorwp causes white pupae phenotypes. Reproductive behaviors in both males and females were strongly regulated by Bdorwp. Remarkably, Bdorwp did not affect the antennal electrophysiology response to 63 chemical components with various structures. It is recommended to indirectly apply Bdorwp as a selectable marker in functional gene research on behavioral modifying chemicals. Moreover, Bdorwp could also be a potential molecular target for developing new insecticides for tephritid species control.