Egg Hatch Research Articles

A mass rearing method to aliquot and hatch Aedes mosquito eggs using capsules

The sterile insect technique (SIT) is a sustainable genetic control method to effectively suppress mosquito vector populations below sanitary and nuisance thresholds. The SIT requires a cost-effective production and release of radio sterilized insects of high and consistent quality and quantity. In this study, we report a new procedure to hatch, aliquot and introduce Aedes albopictus and Aedes aegypti larvae into larval mass rearing units using dissolvable vegetable capsules containing brushed eggs and larval diet. The results demonstrated that the egg brushing procedures, the opening of the hatching container and the presence of diet in the hatching solution increased Aedes eggs hatching success. The diet added during the hatching process decreased the dissolved oxygen (DO) concentration, which constituted the main stimulus for egg hatching success in both species. However, a DO reduction below 3 mg/l can effectively stimulate hatching in both species regardless of the deoxygenation method adopted. The capsule method produced similar hatching success without affecting larval survival and pupation rates in comparison with standard hatching procedures. The use of capsules eliminates intermediate laborious procedures for hatching, counting and transferring larvae into mass rearing trays with an expected improvement in production times and costs for Aedes SIT operational programs.

Koi Fish (Cyprinus rubrofuscus Lacepede, 1803) Breeding Techniques at the Center for Freshwater Aquaculture (BBPBAT) Sukabumi, West Java

One of the economically valuable aspects of fisheries development is ornamental fish farming. Koi farming has advantages as the fish can easily adapt to various environments. The breeding activities included broodstock maintenance, spawning and nursery tank preparation, broodstock selection, hormone injection, egg hatching, larva care, nursery stages, and harvesting. This research is intended to help the author learn and understand proper koi fish breeding techniques at the Center for Freshwater Aquaculture (BBPBAT) in Sukabumi, West Java. The data collected during this research activity includes both primary and secondary data. Primary data is obtained directly without intermediaries, resulting in raw data. Secondary data, on the other hand, is gathered through intermediaries or indirectly, and is sourced from library reports and information from governmental institutions. In the koi fish breeding activities carried out, it was observed that the koi fish had a fecundity rate of 71,400 eggs, an FR (Fertilization Rate) of 92%, an HR (Hatching Rate) of 97%, an SR (Survival Rate) in Nursery Phase I of 45%, and in Nursery Phase II of 74%.

Exploring the ameliorative potential of rutin against High-Sucrose Diet-induced oxidative stress and reproductive toxicity in Drosophila melanogaster

Sucrose is a vital ingredient in numerous food items consumed regularly. However, exposure to excessive sucrose for a prolonged period can promote health issues. The reproductive system has a delicate physiology that can be targeted by various chemical stressors, including sucrose. Hence, the present in vivo study aims to unveil the impacts of the High-Sucrose Diet (HSD) on the reproductive fitness of Drosophila melanogaster. In addition, the present work has also assessed the protective potential of a bioactive compound, rutin, against it. Here, 1st instar larvae were exposed to HSD (30%) alone and in combination with rutin (100-300µM) till their adult stage. HSD disturbed sex comb morphology in adult males, while fecundity and hatchability of eggs in females. Moreover, HSD triggered gonadal ROS production, oxidative stress, and modulated endogenous antioxidants such as SOD, catalase, and glutathione in both sexes. Nuclear fragmentation and tissue injuries, along with protein and lipid oxidation, were also apparent. Elevated levels of cytosolic Iron suggested an active Fenton reaction in adults. Further, HSD modulated the activities of reproductive and metabolic mediators, including vitellogenin, malate dehydrogenase, glucose-6-phosphate dehydrogenase, and angiotensin-converting enzymes that are critical to overall reproductive fitness. Interestingly, co-treatment with rutin, mainly at 200µM, mitigated these adverse effects and restored reproductive fitness. The protective potential of rutin might be attributed to its ability to normalize redox homeostasis, reduce oxidative stress, and optimize critical enzymes involved in reproductive physiology. These findings suggest that rutin has potential therapeutic implications to counteract the reproductive hazards induced by HSD.

Worldwide used bio-insecticides Cry1Ac toxin have no detrimental effects on E. balteatus but alter the symbiotic microbial communities.

Hoverflies, capable of abilities providing dual ecosystem services including pest control and pollination, are exposed to insecticidal proteins from transgenic plants via pollen and prey aphids. However, the effects of such exposures on hoverflies have never been adequately assessed. Here, we investigated impacts of the most widely used biotoxin Cry1Ac on a representative hoverfly species Episyrphus balteatus through food chain transmission and active toxin exposure. The results showed Cry1Ac can be transmitted into E. balteatus through feeding on Aphis gossypii reared by Bt insect-resistant cotton variety expressing the Cry1Ac toxin, but the biological parameters of E. balteatus including survival rate, growth, development, reproductive capacity, and detoxification-related gene expression, were not significantly affected. Furthermore, the exposure to high-dose Cry1Ac toxin (500 μg/mL) resulted in slight increase of 16.67 % in the activity of detoxification and antioxidant enzyme catalase in E. balteatus and inhibited the egg hatching, partially inducing stress responses. Notably, the exposure to Cry1Ac toxin disrupted the microbiota homeostasis in E. balteatus, and the relative abundances of three dominant symbiotic bacterial genera (Cosenzaea, Wolbachia, and Commensalibacter) in E. balteatus exhibited a 10 % ~ 40 % fluctuation under Cry1Ac toxin stress. Taken together, these results suggest Cry1Ac toxin is not lethal to E. balteatus, but it poses a potential threat to its endosymbiotic bacteria.

Bdyof is a Y-chromosome-specific gene required for male development in Bactrocera dorsalis.

In many organisms, the Y chromosome contains important genes associated with sex determination and male reproductive development. However, there have been few studies of Y-chromosome-specific genes in non-model species due to the incomplete information of Y chromosome genome and difficulty in sequencing. Here, we screened 90 candidate Y-specific sequences in a constructed transcriptome assembly library by using the chromosome quotient method, among which 11 were unreported sequences associated with male reproductive development, including Bactrocera dorsalis Y-specific Oligozoospermia factor (Bdyof) with the highest expression in the testis. CRISPR/Cas9-mediated knockout of Bdyof resulted in abnormal testis development, significantly reduced sperm count, and obviously lower egg hatching rate in homozygous mutant flies. In addition, Bdyof knockout decreased the expression of dsx-M. This results provides new insights into the biological processes related to male reproductive development controlled by the Y-chromosome-specific gene Bdyof, thus providing a promising molecular target for the study of agricultural pests. © 2024 Society of Chemical Industry.

Unveiling the potential of a protease inhibitor from Pleiogynium cerasiferum to combat Helicoverpa armigera by employing sequential purification and multivariate statistical analysis

Crop protection is heavily dependent on the use of chemical pesticides that are not only toxic but also detrimental to the environment. To minimize the chemical approaches of crop protection, this study investigates a natural protease inhibitor PCPI (Pleiogynium cerasiferum protease inhibitor) extracted from the seeds of Pleiogynium cerasiferum as a viable bioresource with biopesticidal properties. PCPI demonstrated inhibitory activity of 92% against bovine trypsin and 89% against Helicoverpa armigera's midgut proteolytic enzymes. Characterization of PCPI revealed a 24 kDa protein with critical inhibitory concentrations of 1.53 µg/ml for H. armigera midgut proteases and 1.31 µg/ml for bovine trypsin. At the concentration of 0.5% (w/w) of PCPI, the deformities in pupae were ~ 82%, adult insects ~ 87%, and egg-laying as well as egg hatching capacity dropped by ~ 81% and 17% respectively. Principal component analysis (PCA), complemented by hierarchical clustering, was applied to assess the nuanced effects of PCPI across the pest's lifecycle. The analysis identified deformities in pupae, adult, adult emergence, and notably, egg laying reduction as variables most responsive to PCPI concentrations. Hierarchical clustering analysis corroborated these PCA findings indicating a concentrated influence on developmental stages and reproduction metrics, signifying the multifaceted impact of PCPI. These insights affirm PCPI's promise as a cornerstone of eco-friendly pest management strategies.

Testing low-risk bioactive compounds on Halyomorpha halys: an improved pipeline of analyses to investigate their effects on the bacterial endosymbiont Candidatus Pantoea carbekii.

The brown marmorated stink bug Halyomorpha halys has become an invasive insect pest of many crops. A promising control strategy to manage the proliferation of H. halys is based on the suppression of its obligate and vertically transmitted uncultivated symbiotic bacterium Candidatus Pantoea carbekii through surface-sterilization of H. halys eggs. Indeed, the application of antimicrobial formulations on the eggs of H. halys could cause mortality of endosymbiont and consequently of newly emerged nymphs. In this study, a microbial live/dead assay was applied directly on H. halys eggs to evaluate Ca. P. carbekii loss of viability after treatments with seven commercial formulations including fungicides (copper hydroxide, sulphur, sweet orange essential oil) and plant biostimulants (flavonoids and chestnut tannin extract) compared with two disinfectants for civil and industrial use (sodium hypochlorite/hydrated sodium/tetraborate decahydrate and peracetic acid/hydrogen peroxide). Impact of mode of application was also evaluated, as surface treatment of egg masses was performed through spraying and dipping in laboratory conditions. Antimicrobial activity data were finally complemented with observations of egg hatching and vitality of the nymphs. The optimization of live/dead staining is useful for evaluating Ca. P. carbekii mortality directly on eggs, providing a rapid and reliable culture-independent approach. Sodium hypochlorite, copper, sulphur, tannins and sweet orange essential oil showed an antimicrobial effect against Ca. P. carbekii and a H. halys egg hatching reduction and nymph's vitality. The antimicrobial and insecticidal effects of these commercial products should be further studied to assess their in-field efficiency as well as the impact of these substances on non-target organisms. The approach followed in this study could be considered a robust pipeline of analyses to evaluate the effectiveness of antimicrobial eco-friendly compounds in symbiotic control of H. halys. © 2024 Society of Chemical Industry.

Suppression of Cadra cautella (Lepidoptera: Pyralidae) development by phytosanitary irradiation doses and their impacts on physiochemical and microbiological quality of dates.

Cadra cautella is a serious insect pest of stored figs and dates. The irradiation sensitivity of different development stages of C. cautella and large-scale testing of the proposed irradiation quarantine doses (50-500 Gy), were investigated. The impact of a PI dose of 400 Gy on the physiochemical and microbiological quality of dry dates (Bartamoda cv.) stored at room temperature was also investigated. An irradiation dose of 100 Gy prevented egg hatching in the F1 generation when 1-3 days old eggs were irradiated. Irradiation doses of 200 and 300 Gy prevented adult emergence when 2nd and 4th instar larvae were irradiated. When the pupae stage was irradiated, an irradiation dose of 400 Gy prevented the hatchability of F1 generation, indicating that this stage was the most radio-tolerant. The results of large-scale testing of the proposed phytosanitary irradiation dose (400 Gy) applied to 18, 0000 pupae resulted in no reproduction (zero hatching of F1 generation). There were no significant differences in the physiochemical properties of stored dates during the storage period at room temperature. Stable ESR signal intensity was recorded for 6 months in all parts of the irradiated fruits, and the intensity was highest in the kernel. The PI dose of 400 Gy also slightly reduced all microorganisms' counts. In conclusion, the dose level of 400 Gy stopped the reproduction potential of C. cautella. and they maintained the quality characteristics of dry date Bartamoda fruits during storage at room temperature for 6 months in tightly closed packages.

Structural characterization and proteomic profiling of oviposition secretions across three rice planthopper species

Insect oviposition secretions play crucial roles during the reproductive process, yet systematic studies on their structural characterization and protein compositions remain limited. This study investigated the oviposition secretions of three major rice pests: the brown planthopper (Nilaparvata lugens, BPH), small brown planthopper (Laodelphax striatella, SBPH), and white-backed planthopper (Sogatella furcifera, WBPH). Ultrastructural observation revealed differences in the oviposition secretions of them. The eggs of BPH and SBPH were adhered to rice tissue by abundant secretions, while WBPH eggs were embedded deeper within the leaf sheath with less secretions. Proteomic analysis identified 111, 98, and 66 oviposition secretion proteins (OSPs) in BPH, SBPH, and WBPH, respectively. 4 common protein subgroups were shared among them, along with varying numbers of shared subgroups between species pairs. Notably, the majority of OSPs were exclusively found in one species, indicating the existence of both similar and specialized functions unique to each planthopper species. The functions of 4 uncharacterized OSPs (Nl.chr07.0363, Nl.chr12.078, Nl.chr11.716, Nl.scaffold.0714) that were uniquely identified in the BPH were studied by maternal RNAi. Downregulation of each of these 4 protein-coding genes led to a significant decrease in egg production and hatchability. Moreover, knockdown of Nl.chr12.078 or Nl.chr07.0363 also disrupt the secretory function of the lateral oviduct. In conclusion, this study provides insights into the structural characteristics and protein components of the oviposition secretions of BPH, SBPH, and WBPH, which could serve as potential targets for RNAi-based pest control and lay a foundation for future studies on insect-plant interactions mediated by oviposition secretions.

Natural variation in timing of egg hatching, response to water agitation, and bidirectional selection of early and late hatching strains of the malaria mosquito Anopheles gambiae sensu lato

BackgroundEggs of anopheline mosquitoes hatch within a few days of laying and require high levels of humidity to survive. Assessing natural variation in egg hatching and its environmental and genetic determinants in sibling species of the malaria vector Anopheles gambiae s.l. is important for understanding their adaptation to variable aquatic habitats. Crucially, it can also inform insectary rearing practices toward the optimization of mosquito production for genetic vector control strategies.MethodsHatching rates and timing of egg hatching in long-established and recently colonized strains of An. gambiae s.s, Anopheles arabiensis, and Anopheles coluzzii, were compared under still water conditions (26 ℃) and with cold (4 ℃) and (15 ℃) water agitation regimes. Next, early and late hatching strains of the recently colonized An. coluzzii VK colony were generated through bidirectional selection for 18–23 generations to detect a genetic component for this trait.ResultsHatching rates differed significantly between species and treatments. The older An. arabiensis Senn and An. gambiae s.s. Kisumu strains had the highest proportion of hatching and preferred the nonagitation treatment at 26 °C. In contrast, the more recently colonized An. coluzzii VK and An. arabiensis Rufisque strains had lower overall hatching success but responded strongly to agitation at 4 °C, while the An. coluzzii Mopti strain did not significantly respond to water agitation. In all strains, eggs hatching started at day 2 and continued till day 5 in the older strains, whilst it was more staggered and extended up to day 6 in the younger strains. Bidirectional selection for early and late hatching over many generations resulted in early hatching selected strains with eggs hatching 2–3 days earlier than in late hatching ones indicating a significant heritable component for these traits.ConclusionsWater agitation and temperature and age of colonization are likely important determinants of egg hatching in natural An. gambiae s.l. populations. Current rearing protocols systematically select for fast hatching and result in the progressive loss of staggered egg hatching in older laboratory strains. The selection of novel slow-hatching strains may prove instrumental to enable the mass production, shipping, and release of Anopheles mosquitoes across Africa as part of genetic vector control programs.Graphical

Cocktail vaccine for the management of Hyalomma anatolicum and Rhipicephalus microplus.

Globally, ticks rank second only to mosquitoes as vectors of deadly pathogens affecting humans and first in transmitting animal pathogens, presenting a significant challenge to human wellness and sustainability of livestock-based industries. Traditional tick control via chemical acaricides impacts on the environment and has led to the emergence of multi-acaricide-resistant tick populations. Use of immunoprophylactic, along with other components of integrated tick management, holds the potential to mitigate tick infestations in a sustainable manner. To control multi-species tick infestations, the concept of a cocktail vaccine comprising of more than one antigens has emerged as a viable solution due to the inconsistent efficacy of single antigen-based immunization protocol. In this study, a dual antigen cocktail immunization protocol was developed targeting ferritin2 (FER2) and tropomyosin (TPM) proteins, which are associated with ticks' essential cellular and physiological functions, like blood iron homeostasis and muscle contractions. Dual gene silencing of FER2 and TPM genes in Hyalomma anatolicum resulted in a 75.3% reduction in infested ticks, a 95.4% decrease in egg masses, and a complete loss of egg hatching when compared to control ticks. Microscopically, an altered ovarian cellular architecture, marked by vacuolation and reduced nucleus-to-cytoplasmic ratio were noted in the gene knocked down ticks. An immunization with cocktails of 300 µg dose of each protein, rHaFER2 and rHaTPM was standardized in a rat model and was used to immunize cross-bred (Bos indicus x B. taurus) male cattle with Montanide ISA 50V2 adjuvant on days 0, 28, and 49. A significant (p < 0.001) IgG and IgG2 antibody response was observed in the immunized animals with high IgG levels sustained until day 119 post-primary immunization, showing a 4.1-fold increase over the pre-immunization period. The animals were challenged with larvae and adults of H. anatolicum and larvae of Rhipicephalus microplus. Immunization with the cocktail antigen resulted an efficacy of 70% and 76% against H. anatolicum larvae and adults, respectively, and 54% against R. microplus infestations. Compared to single-antigen immunization, the immunization with cocktail antigens demonstrated higher protection against R. microplus and H. anatolicum ticks. The results advance the development of cocktail vaccines to control multiple tick species.

Investigating the Potential of X-Ray-Based Cancer Treatment Equipment for the Sterile Insect Technique in Aedes aegypti Control Programs.

The sterile insect technique (SIT) stands as an eco-friendly approach for mosquito control, but it is impeded by the limited availability of γ-ray radiation source. This research sought to investigate a different radiation source-the Varian Clinac 23EX linear accelerator, which is frequently used for X-ray therapy in cancer treatment. Evaluation parameters including emergence rate, average survival time, induced sterility (IS), male mating competitiveness of irradiated males and fecundity (the number of eggs per female per batch), and the egg hatch rate of females mated with irradiated males were assessed to gauge the application potential of this cancer treatment equipment in the realm of the SIT. The results indicated that X-rays from radiation therapy equipment can effectively suppress the hatch rate of offspring mosquitoes without adversely affecting the emergence rate of irradiated males or the fecundity of females. In addition, at an X-ray dose of 60 Gy, the induced sterility in Ae. aegypti was comparable to the sterility induced by 40 Gy of γ-rays with both treatments resulting in 99.6% sterility. Interestingly, when a release ratio of 7:1 (irradiated males:unirradiated males) was used to competitively mate with females, the IS results resulted by 60 Gy X-rays and 40 Gy γ-rays were still at 70.3% and 73.7%, respectively. In conclusion, the results underscored the potential of the Varian Clinac 23EX linear accelerator as an X-ray source in SIT research.

Curcuma longa essential oil as an acaricidal agent for the control of cattle ectoparasitic tick - Rhipicephalus (Boophilus) annulatus

well known for its insecticidal, anti-inflammatory, antioxidant, anticancer, anti-rheumatic and antibiotic properties, Turmeric (Curcuma longa L.) Essential oil (EO), is effective in repelling and controlling many different pest species. The present study evaluates in vitro efficacy of turmeric EO against ectoparasitic tick, Rhipicephalus (Boophilus)annulatus collected from their natural host, domesticated cows. Repellency and toxicity of the EO on ectoparasitic ticks was analyzed with petri dish choice bioassay and AIT (Adult immersion test) against adult engorged females and nymphal stages of ticks. The Repellency Concentration (RC50) and Lethal Concentration (LC50) reproductive index, inhibition of oviposition and egg hatchability of treated ticks were estimated. GC-MS analysis identified Ar-turmerone as the major phytochemical, which induces adulticidal and repellant properties of EO. The nymphal stages of the ticks exhibited greater repellency on application of EO than the adult stage. Also, EO induced effective mortality in adult ticks. Further, this lethal concentration is capable of producing a decreased output in reproductive parameters namely, fecundity, % of oviposition and egg hatchability in surviving ticks thereby considerably reducing Rhipicephalus (Boophilus) R(B). annulatus population on its host. This study reveals the potency C. longa EO to be used as an effective pest control agent against R (B). annulatus infestation that can serve as an alternative to synthetic pesticides.

The SA-WRKY70-PR-Callose Axis Mediates Plant Defense Against Whitefly Eggs.

The molecular mechanisms of plant responses to phytophagous insect eggs are poorly understood, despite their importance in insect-plant interactions. This study investigates the plant defense mechanisms triggered by the eggs of whitefly Bemisia tabaci, a globally significant agricultural pest. A transcriptome comparison of tobacco plants with and without eggs revealed that whitefly eggs may activate the response of defense-related genes, including those involved in the salicylic acid (SA) signaling pathway. SA levels are induced by eggs, resulting in a reduction in egg hatching, which suggests that SA plays a key role in plant resistance to whitefly eggs. Employing Agrobacterium-mediated transient expression, virus-induced gene silencing assays, DNA-protein interaction studies, and bioassays, we elucidate the regulatory mechanisms involved. Pathogenesis-related proteins NtPR1-L1 and NtPR5-L2, downstream of the SA pathway, also affect whitefly egg hatching. The SA-regulated transcription factor NtWRKY70a directly binds to the NtPR1-L1 promoter, enhancing its expression. Moreover, NtPR1-L1 promotes callose deposition, which may impede the eggs' access to water and nutrients. This study establishes the SA-WRKY70-PR-callose axis as a key mechanism linking plant responses and defenses against whitefly eggs, providing new insights into the molecular interactions between plants and insect eggs.

Pleiotropic effects of Ebony on pigmentation and development in the Asian multi-coloured ladybird beetle, Harmonia axyridis (Coleoptera: Coccinellidae).

Melanin plays a pivotal role in insect body pigmentation, significantly contributing to their adaptation to diverse biotic and abiotic environmental challenges. Several genes involved in insect melanin synthesis showed pleiotropic effects on insect development and reproduction. Among these, the N-β-alanyl dopamine synthetase gene (Ebony) is integral to the pigmentation process. However, the full spectrum of its pleiotropic impacts is not yet thoroughly understood. In this study, we identified and characterised the HaEbony gene in the Asian multi-coloured ladybird beetle (Harmonia axyridis) and found that HaEbony gene is a conserved gene within the Coleoptera order. We aimed to further explore the multiple roles of HaEbony in the physiology and behaviour in H. axyridis. The CRISPR/Cas9 system was applied to generate multiple HaEbony knockout allele (HaEbony+/-), showing nucleotide deletion in the G0 and G1 generations. Remarkably, the resultant HaEbony+/- mutants consistently displayed darker pigmentation than their wild-type counterparts across larval, pupal and adult stages. Furthermore, these HaEbony+/- individuals (G0) demonstrated an enhanced predatory efficiency, evidenced by a higher number of aphids consumed compared to the wild type. A significant finding was the reduced egg hatchability in both G0 and G1 generations of the HaEbony+/- group, highlighting a potential reproductive fitness cost associated with HaEbony deficiency. In conclusion, our study not only sheds light on the multifaceted roles of HaEbony in H. axyridis but also highlights the potential of employing CRISPR/Cas9-targeted modifications of the Ebony gene. Such genetic interventions could enhance the environmental adaptability and predatory efficacy of ladybirds, presenting a novel strategy in biological control application.

Gene flow stimulates recovery of reproductive fitness in a captive bred insect

Abstract Captive breeding can be a useful tool for the management of threatened species, but such programs often begin with a bottleneck which may lower reproductive fitness by increasing inbreeding and allowing deleterious alleles to increase in frequency by reducing effective population size. Dryococelus australis, the Lord Howe Island stick insect, is a critically endangered insect that has been bred at the Melbourne Zoo in Melbourne, Australia, since shortly after the species was rediscovered in 2001. We analysed a long‐term dataset of phenotypic measurements from this captive breeding program to determine whether reproductive fitness has declined in captivity. We found a clear signal of decline in direct (egg hatching success) and indirect (egg and nymph size) fitness indicators over time. We compared a captive line descended from the original program founders to a new hybrid line that has recent wild ancestry. The hybrid line showed an immediate improvement in egg hatch rate, suggesting the potential for genetic rescue. Egg and nymph size did not show as dramatic a change, although this line had only existed for just over a single generation at the time of data collection. These results argue strongly for the regular sourcing of new genetic material from the wild D. australis population to counteract fitness declines in captivity. Aside from benefiting the captive population, this would also improve the prospects of establishing new wild populations in the future, using individuals sourced from captivity.

The oviposition of cotton bollworms stimulates the defense against its eggs and larvae in tomato plants.

Herbivorous insects sustain their populations by oviposition. To reduce the damage caused by herbivores, the host plant triggers a defensive response upon detection of egg deposition. However, the specific impact of the egg deposition time of the cotton bollworm Helicoverpa armigera (Lepidoptera: Noctuidae), on the tomato plant defense remains obscure. This study investigated the effects of tomato plant defenses on cotton bollworm eggs and larvae at different time intervals following egg deposition. The study revealed that tomato plant defense triggered by egg deposition did not directly affect the hatchability of the eggs. Nevertheless, it attracted Trichogramma chilonis 48 h after the egg deposition. Gas chromatography-mass spectrometry analysis of the oviposition-induced plant volatiles (OIPVs) revealed a considerable increase in the amount of α-pinene released by tomato plants 48 h after egg deposition. The olfactory results from Y-tube experiments showed that α-pinene exhibited a substantial attraction towards T. chilonis. In addition, it was found that the defense response induced by egg deposition for 24 and 48 h significantly inhibited the growth and development of the larvae. Metabolomics analysis revealed that the egg deposition of cotton bollworm altered the metabolite composition and caused significant modifications in the metabolic pathways of tomato plants. These findings provide novel insights into pest management by using egg-induced plant defenses to reduce egg hatching, and impede larval growth and development in herbivorous insects. © 2024 Society of Chemical Industry.

Purification and Identification of the Nematicidal Activity of S1 Family Trypsin-Like Serine Protease (PRA1) from Trichoderma longibrachiatum T6 Through Prokaryotic Expression and Biological Function Assays.

Heterodera avenae is a highly significant plant-parasitic nematode, causing severe economic losses to global crop production each year. Trichoderma species have been found to parasitize nematodes and control them by producing enzymes that degrade eggshells. The T. longibrachiatum T6 (T6) strain has been demonstrated the parasitic and lethal effects on H. avenae cysts and eggs, associated with the increased serine protease activity and trypsin-like serine protease gene (PRA1) expression. Our present study aimed to purify the recombinant PRA1 protease through a prokaryotic expression system and identify its nematicidal activity. The recombinant PRA1 protease was identified as S1 family trypsin-like serine protease, with a molecular weight of 43.16 kDa. The purified soluble protease exhibited the optimal activity at 35 °C and pH 8.0, and also demonstrating higher hydrolytic ability toward casein and skimmed milk. Meanwhile, the Ca2+ and Mg2+ enhanced its activity, while the inhibitor PMSF significantly reduced it. The contents of H. avenae eggs leaked out after treatment with the recombinant PRA1 protease, with egg hatching inhibition and relative hatching inhibition rates at 70.60% and 66.58%, respectively. In contrast, there was no sign of content dissolution, and embryos developed normally in the control group. Our present study revealed that the PRA1 protease of T6 strain has a lethal effect on H. avenae eggs, which providing a theoretical basis for developing biocontrol agents to control nematodes.

Enhanced mite control and agricultural safety with etoxazole-loaded chitin nanocrystals: Synthesis, characterization, and ecological impacts

Chitin nanocrystals (ChNCs), known for their high aspect ratio, surface charge, and mobility, are promising bio-based nanomaterials for drug delivery. However, their potential as pesticide carriers in agriculture remains underexplored. Etoxazole, a diphenyl oxalate acaricide, effectively inhibits egg hatching and the normal molting process in mites but suffers from rapid degradation and short persistence in field applications. This study introduces a novel formulation, Eto@ChNC, prepared by complexing TEMPO-oxidized ChNCs with etoxazole via a one-pot method. Eto@ChNC was evaluated for controlling Tetranychus urticae, demonstrating significantly enhanced rapid action and prolonged efficacy compared to traditional formulations. The formulation increased the synergistic effects on mite eggs and deutonymphs by 41.74 % and 67.85 %, respectively, extending effectiveness by two days. The improved performance was attributed to the enhanced wetting ability of Eto@ChNC on leaf surfaces and its superior inhibition of the epidermal chitin content in T. urticae, facilitating greater etoxazole penetration. Transcriptome sequencing revealed numerous differentially expressed genes related to chitin metabolism, elucidating the molecular mechanisms underlying the increased efficacy. Safety assessments confirmed that Eto@ChNC did not elevate toxicity to earthworms or predatory mites and promoted the growth of wheat and cowpea, underscoring its environmental safety. These findings highlight Eto@ChNC as a significant advancement in bio-based acaricide formulations, offering promising applications in mite management.

Comparative fertility and hatchability of broiler grandparent stocks in Bangladesh

Checking the fertility and hatchability of broiler grandparent lines is important for improving chicken production. The Cobb-500, Ross-308, and Indian River (IR) grandparent strains were studied to determine their initial egg weight, fertility, hatchability, embryonic mortality, hatching weight, and chick survival rates. We studied a total of 2700 eggs from three different age/treatment, each consisting of three replicates with 100 eggs for each of the three genotypes. Using an automated incubator, eggs were incubated. Cobb-500 had a significantly higher mean egg weight (67.52 g) at later stage of their age compared to Ross-308 (64.22 g) and IR (65.05 g). Study also found that a higher egg weight reflects a higher day-old chick weight. The fertility rates of the Ross-308, IR, and Cobb-500 genotypes were high at 35 weeks (96.00%, 87.00%, and 93.00%) but declined after 45 weeks (64.22%, 65.05%, and 67.52%), respectively. The hatchability of Ross-308, IR, and Cobb-500 eggs at 35 weeks was 85.00%, 75.00%, and 80.00%, respectively. By 45 weeks, all genotypes had higher hatchability, with Ross-308 having the highest at 89%. But at 55 weeks, all genotype showed lowest hatchability where IR was the lowest 67%. Statistically significant variations were observed across strains at later stage. As age increased, embryonic mortality and brood mortality were higher. Compared to the other two, Ross-308 showed the lowest mortality in both embryonic and brooding cases in all three stages of their age of life. However, the IR breed consistently displayed the highest mortality rate. Same pattern showed dead in shell and culling chick’s percentages. Strain-wise, the parameters differ from each other. However, regarding overall performance, the Ross-308 strain outperformed the other two strains. Asian Australas. J. Food Saf. Secur. 2024, 8(2), 48-57