Egg Hatch Research Articles

Effect of cattle and horse feces storage methods on Nematode egg viability and sensitivity for egg hatch test

The aim of the present study was to validate methods of stool sample conservation for the egg hatch test (EHT). This study involved the use of a bovine naturally infected predominantly by Cooperia spp. and one equine naturally infected predominantly by cyathostomins characterized as susceptible to benzimidazoles in the EHT. Fecal samples were submitted to three treatments: aerobic methods (anaerobic storage in plastic bottles, anaerobic storage in vacuum-sealed bags or aerobic storage in plastic bags), under two temperature conditions (room temperature and refrigeration) analyzed at four different assessment times (48, 72, 96 and 120 h). As the standard test, an assay was also performed within 3 h. The tests were performed in triplicate for each drug concentration and with three experimental repetitions at one-week intervals. Two criteria were used for the storage methods: hatchability in the negative control group and sensitivity of the eggs to thiabendazole, comparing the EC50 and 95% confidence interval for each treatment to those of the standard test and the other repetitions. Bovine samples can be stored for up to 96 h and refrigerated vacuum storage can be used, ensuring hatchability of the negative control and sensitivity of the eggs to thiabendazole. For equine samples, no forms of storage were indicated due to the variation among the repetitions and the reduction in the sensitivity of the eggs to thiabendazole, which could result in a false positive detection of resistance.

Functional characterization of helminth-associated Clostridiales reveals covariates of Treg differentiation

BackgroundParasitic helminths influence the composition of the gut microbiome. However, the microbiomes of individuals living in helminth-endemic regions are understudied. The Orang Asli, an indigenous population in Malaysia with high burdens of the helminth Trichuris trichiura, display microbiotas enriched in Clostridiales, an order of spore-forming obligate anaerobes with immunogenic properties. We previously isolated novel Clostridiales that were enriched in these individuals and found that a subset promoted the Trichuris life cycle. In this study, we aimed to further characterize the functional properties of these bacteria.ResultsClostridiales isolates were profiled for their ability to perform 57 enzymatic reactions and produce short-chain fatty acids (SCFAs) and hydrogen sulfide, revealing that these bacteria were capable of a range of activities associated with metabolism and host response. Consistent with this finding, monocolonization of mice with individual isolates identified bacteria that were potent inducers of regulatory T-cell (Treg) differentiation in the colon. Comparisons between variables revealed by these studies identified enzymatic properties correlated with Treg induction and Trichuris egg hatching.ConclusionWe identified Clostridiales species that are sufficient to induce high levels of Tregs. We also identified a set of metabolic activities linked with Treg differentiation and Trichuris egg hatching mediated by these newly isolated bacteria. Altogether, this study provides functional insights into the microbiotas of individuals residing in a helminth-endemic region.-EyM7p7tfAvrAjtAePB85JVideo

Evaluating anthelmintic activity through Caenorhabditis elegans egg hatching assay

The Caenorhabditis elegans egg hatching methodology is a valuable tool for assessing the anthelmintic activity of drugs and compounds and evaluating anthelmintic drug efficacy.Isolated eggs from gravid adults are exposed to different concentrations of selected drugs and the percentage of egg hatching is determined with respect to the control condition. The assay allows the construction of concentration-response curves and determination of EC50 or EC90 values for egg hatching inhibition. Also, it allows measurements of inhibition as a function of time of exposure.This approach addresses the urgent need for new anthelmintics, as resistance to current treatments poses a significant challenge in parasitic nematode infection. This resistance not only affects humans but also animals and plants, causing significant economic losses in livestock farming and agriculture.By using the free-living nematode C. elegans as a parasitic model organism, researchers can efficiently screen for potential treatments and assess drug combinations for synergistic effects. Importantly, this assay offers a cost-effective and accessible alternative to traditional methods, eliminating the need for specialized infrastructure, hosts, and trained animal maintenance personnel. Additionally, the methodology closely mimics natural conditions, providing insights into egg development and potential therapeutic targets.This method allows for evaluating the direct negative impact of drugs on egg hatching, which correlates with long-term anthelmintic effects, offering advantages in preventing or reducing the transmission and spread of worm infections by eggs.Overall, this approach represents a significant advancement for anthelmintic discovery, offering both practical applications and avenues for further scientific research.•The C. elegans egg hatching assay is a robust and effective method for assessing the anthelmintic potential of various drugs and compounds, allowing the generation of concentration-response curves.•By leveraging the free-living nematode C. elegans as a parasitic model organism, this method facilitates efficient screening of potential treatments and evaluation of drug combinations.•The method addresses the urgent need for new anthelmintics, offering a cost-effective and accessible alternative to traditional approaches.

Effects of relative humidity on egg hatching success of blow flies (Diptera: Calliphoridae)

Humidity can influence oviposition decisions by females and the development and survival of offspring. We measured the impact of relative humidity on egg eclosion of three forensically relevant blow fly species: Lucilia sericata (Meigen), Phormia regina (Meigen) and Calliphora vicina Robineau-Desvoidy (Diptera: Calliphoridae). Egg masses were placed into glass jars lined with filter paper and placed into growth chambers at 25°C with 12:12 L:D, across six levels of relative humidity (30, 40, 50, 60, 70, and 80%). Eggs were observed every six hours for eclosing larvae to measure the effect of humidity on time to egg eclosion. As relative humidity increased, time to eclosion decreased for all three species. Calliphora vicina hatching success was the least affected by humidity, maintaining greater than 60% hatching success even at 30% relative humidity. In contrast, L. sericata required at least 50% relative humidity to have hatching success above 60%. Phormia regina was the most affected by humidity, requiring relative humidity to be above 70% to reach hatching success above 60%. Given the differential effect of relative humidity on egg hatching, these results may have implications for oviposition decisions made by female blow flies.

Analisis Usaha dan Pemasaran Pembenihan Udang Windu (Penaeus monodon) di HSRT Windu Tirta Samudra Desa Tanjung Limau Kecamatan Muara Badak

Tiger shrimp farming is an aquaculture business associated with the rearing of shrimp from egg hatching until they are ready to be harvested for consumption. The amount of tiger shrimp production is highly dependent on the tiger shrimp hatchery process. This study was conducted with the aim to 1) Calculate the income of tiger shrimp hatchery business, 2) Analyze the feasibility of tiger shrimp hatchery business based on the criteria of Revenue Cost Ratio (RCR), Break Even Point (BEP), Payback Period, Return On Investman (ROI), and 3) Describe marketing channels, marketing margins, and farmer share in shrimp hatchery business. The sample method used was purposive sampling and snowball sampling. The results showed that tiger shrimp hatcheries in HSRT Windu Tirta Samudra earned an income of Rp.43,313,992/month. Based on the criteria of RCR, BEP, ROI and Payback Period (PP) tiger shrimp hatchery business is feasible to continue and run. Marketing of tiger shrimp seed forms level 0 and level 1 marketing channels, with a margin of Rp.2/head on level 1 marketing channels, and the farmer's share obtained is efficient because it is above 60%.

Phytochemicals, antioxidant ability and in vitro anthelmintic activity of crude extracts from Vitexnegundo leaves against Haemonchus contortus.

The aim of this study was to evaluate the in vitro anthelmintic effect of crude aqueous, methanol, ethanol, hydro alcohol and acetone extracts of Vitex negundo leaves against Haemonchus contortus eggs and larvae. Phytochemical analysis to identify the number of compounds in extracts was done by chemical tests and gas chromatography coupled to a mass spectrophotometer detector (GC-MS). First off all the effectiveness of dried plant materials was evaluated on larval development by mixing powdered material (no nano particles) to faecal cultures from donor sheep. Adding powder to the faecal culture resulted into 100% inhibition in larval development at 200 and 300mg/g of faeces. The anthelmintic activity was assessed using the egg hatch assay (EHA) and the larval mortality assay (LMA). Comparison of mean inhibition percentage of egg embryonation, mean inhibition percentage of egg hatching and mean percentage of larval mortality at different concentrations with control was performed by one-way ANOVA. The means were compared for statistical significance using DMRT at P < 0.05. For both the assays, 50% inhibitory concentration (IC50) and lethal concentration (LC50) were calculated by probit analysis. Chemical test revealed presence of high concentration of saponin and flavoinoids and moderate concentration of total phenols in leaves. The antioxidant activity (radical scavenging activity, RSA %) measured was 35.47%. On GC-MS, the methanolic leaves extract revealed 30 phyto-compounds. On EHA, there was marked effect on inhibition of egg hatching by aqueous, hydro alcohol and acetone extracts. On LMA all the five extracts showed excellent larvicidal activity. V. negundo leaves methanol extract mediated silver nanoparticles were found very effective at much lower concentrations as compared to crude methanol extract. The results indicated that the V. negundo leaves crude extracts possessed excellent in vitro ovicidal and larvicidal properties against H. contortus which needs more investigation, especially in vivo trials for the control of parasite.

Sulfonamide modified chitosan oligosaccharide with high nematicidal activity against Meloidogyne incognita

Chitosan oligosaccharide (COS) modification is a feasible way to develop novel green nematicides. This study involved the synthesis of various COS sulfonamide derivatives via hydroxylated protection and deprotection, which were then characterized using NMR, FTIR, MS, elemental analysis, XRD, and TG/DTG. In vitro experiments found that COS-alkyl sulfonamide derivatives (S6 and S11–S13) exhibited high mortality (>98 % at 1 mg/mL) against Meloidogyne incognita second-instar larvaes (J2s) among the derivatives. S6 can cause vacuole-like structures in the middle and tail regions of the nematode body and effectively inhibit egg hatching. In vivo tests have found that S6 has well control effects and low plant toxicity. Additionally, the structure-activity studies revealed that S6 with a high degree of substitution, a low molecular weight, and a sulfonyl bond on the amino group of the COS backbone exhibited increased nematicidal activity. The sulfonamide group is a potential active group for developing COS-based nematicides.

Diverging phenology of American lobster (Homarus americanus) larvae and their zooplankton prey in a warming ocean

Abstract We build on previous research describing correlative links between changes in the abundance of the copepod Calanus finmarchicus, a foundational zooplankton species of the pelagic food web, and diminishing recruitment of young-of-year American lobster (Homarus americanus) to benthic nurseries in the Gulf of Maine. Using parallel 31-year time series of lobster larvae and zooplankton collected on the New Hampshire coast between 1988 and 2018, we investigated how changes in phenology of stage I larval lobster and their putative copepod prey, C. finmarchicus, affect their temporal overlap and potential to interact during the larval season. We found that over the time series both the lobster egg hatch and first appearance of larvae began earlier in the season, a trend significantly correlated with ocean warming. The last appearance of larvae in late summer has been delayed, however, thereby extending the larval season. Even with the longer larval lobster season, the C. finmarchicus season has increasingly been ending before the peak abundance of stage I lobster larvae. The net effect is a widening mismatch in phenology of the two species, an outcome consistent with the hypothesis that changes in abundance and phenology of C. finmarchicus have contributed to recent declines in lobster recruitment.

Influence of abiotic factors on diapause termination and temperature requirements for postdiapause development in the European red mite, Panonychus ulmi (Acari: Tetranychidae).

The European red mite Panonychus ulmi (Koch) is widely distributed and it can severely affect pome fruit crops, particularly apple. Pest outbreaks are related to an overuse of non-selective pesticide treatments that lead to the development of resistance and the absence of natural enemies in the orchard. A key aspect to optimize the use of pesticide treatments in the context of IPM is to increase the knowledge on the biology and ecology of the pest to better predict population dynamics and outbreaks. For the European red mite, knowledge on the conditions that lead to diapause breaking by winter eggs is essential to model population dynamics. To increase this knowledge, winter eggs were collected during field surveys in northen Spain during three years and egg hatching was monitored under controlled temperature and photoperiod conditions in the laboratory. The "number of days exposed to cold temperatures" was the most significant factor that positively affected hatching of overwintering eggs. The time required for 50% of the egg population to hatch (T50%) was also negatively modulated by the duration of exposure to cold temperature. The temperature threshold for postdiapause eggs development collected from the field was estimated between 5 and 6 ºC in 2005 and 2007, respectively. Moreover, the degree-days required for post diapause development were estimated between 263.2 and 270.3, depending on the year of collection. Collectively, we provide additional information on the diapause termination and postdiapause development of the European red mite that may effectively contribute to optimize pest population models.

Implementation of Internet of Things for Egg Incubation Control System

An egg incubator is a technology in the livestock industry used for automated and efficient egg hatching. However, in its development, existing egg incubators only utilize incandescent lamps without any notification system to indicate when the chicken eggs have hatched, and there is no temperature or humidity detection in the incubator. As a result, the incubator’s situation during the egg hatching process remains uncontrolled. Therefore, this research, we designed and constructed an egg incubator machine that utilizes a microcontroller as the main control unit, responsible for regulating temperature, humidity, and egg rotation. Through the implementation of the Internet of Things, this egg incubator is connected to the internet as a communication tool using specialized software, allowing farmers to remotely monitor the device. Users receive information about the incubator machine through the Telegram mobile application, such as the current temperature and humidity inside the incubation room, up to the hatching status of the eggs. Based on the test results conducted, it can be concluded that the hardware has been successfully developed using the Microcontroller. In the temperature sensor test, there was an average error of 3.14% in temperature readings and error 5.91% in humidity readings. Overall, the device has functioned well and as intended, which includes temperature and humidity readings, controlling the timing of the lamp, and shifting the egg tray. The performance test of the device successfully hatched eggs on time (for 21 days) with a success rate of 90%.

Effect of Silencing subolesin and enolase impairs gene expression, engorgement and reproduction in Haemaphysalis longicornis (Acari: Ixodidae) ticks.

Haemaphysalis longicornis is an obligate blood-sucking ectoparasite that has gained attention due its role of transmitting medically and veterinary significant pathogens and it is the most common tick species in Republic of Korea. The preferred strategy for controlling ticks is a multi-antigenic vaccination. Testing the efficiency of a combination antigen is a promising method for creating a tick vaccine. The aim of the current research was to analyze the role of subolesin and enolase in feeding and reproduction of H. longicornis by gene silencing. In this study, we used RNA interference to silence salivary enolase and subolesin in H. longicornis. Unfed female ticks injected with double-stranded RNA targeting subolesin and enolase were attached and fed normally on the rabbit's ear. Real-time polymerase chain reaction was used to confirm the extent of knockdown. Ticks in the subolesin or enolase dsRNA groups showed knockdown rates of 80% and 60% respectively. Ticks in the combination dsRNA (subolesin and enolase) group showed an 80% knockdown. Knockdown of subolesin and enolase resulted in significant depletion in feeding, blood engorgement weight, attachment rate, and egg laying. Silencing of both resulted in a significant (p < 0.05) reduction in tick engorgement, egg laying, egg hatching (15%), and reproduction. Our results suggest that subolesin and enolase are an exciting target for future tick control strategies.

The comparative egg physical characteristics from four poultry species

In this study, we examined the physical characteristics of two local breeds (Cemani chicken and Mojosari putih duck) and two imported breeds (White Leghorn chicken and Peking duck). A total of 280 eggs were tested. Egg physical characteristics and hatchability were analyzed using ANOVA with consideration for breed effects using GLM (SPSS version 25). Peking ducks have a heavier, larger mean of geometric diameter, larger volumes, and larger surface area of eggs (p<0.05). Among them, the Cemani chicken is the smallest in the world (p<0.05). Cemani chicken and Mojosari putih ducks had the highest sphericity and shape index scores, and were significantly different from White Leghorn chickens and Peking ducks (p<0.05). Density parameters were highest in Cemani chickens as well as in White Leghorn chickens, but were significantly different from Peking ducks and Mojosari putih ducks (p<0.05). Hatchability was related to the shape index value. Mojosari putih ducks and Cemani chickens have a higher shape index than White Leghorn chickens and Peking ducks. In summary, the Peking duck was better, but the hatchability was higher for the Mojosari putih duck and Cemani chicken.

CRISPR/Cas9 mediated validation of spermatogenesis-related gene, tssk2 as a component of genetic pest management of fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae).

Invasive insect pests, currently, pose a serious economic threat to several staple crops all over the world, one such being the fall armyworm, Spodoptera frugiperda. It was first observed in Africa since 2016, outside of its natural habitat in the Americas. Subsequently, it invaded several countries in South and South East Asia and also very recently in Australia. In all the newly invaded regions, maize is the principal crop attacked causing a serious economic concern to the poor farmers, particularly in the developing countries. Owing to the innate genetic ability, it defies many of the management options that include insecticides, Bt transgenics, and so forth. This is due to its high mobility, polyphagy and ability for quick development of resistance to several classes of insecticides. At this critical juncture, CRISPR/Cas9 mediated genome editing has shown a lot of promise in developing a novel area-wide pest management strategy called precision-guided sterile insect technique (pgSIT). pgSIT was initially demonstrated in Drosophila melanogaster which holds a greater promise for the environmentally friendly management of several globally significant agricultural pests such as S. frugiperda. Therefore, before developing both sgRNA and Cas9 transgenic lines, we have validated the target gene such as tssk2 through a non-transgenic approach by microinjecting ribo nucleo protein complex (Cas9 protein and tssk2 sgRNA) into G0 eggs of S. frugiperda. In the current investigation, we have obtained five edited males with distinct mutations which were further used for crossing studies to ascertain the effect of tssk2 editing affecting egg hatchability.

LIFE HISTORY PARAMETERS OF MELON FRUIT FLY, BACTROCERA CUCURBITAE (COQUILLETT) (DIPTERA: TEPHRITIDAE) ON FOUR ECONOMICALLY IMPORTANT VEGETABLES

The majority of plant species that are used for consumption and medicinal purposes belongs to Cucurbitaceae. These vegetables are attacked by several insect pests including Tephritid flies. Keeping in view, four economically important cucurbit vegetables such as sponge gourd; Luffa aegyptiaca, bitter gourd; Momordica charantia, musk melon; Cucumis melo, and bottle gourd; Lagenaria siceraria were selected to investigate the life-history parameters of Bactrocera cucurbitae (Coq.) (Diptera: Tephritidae) under laboratory conditions. For this purpose, B. cucurbitae was reared in the laboratory on each host vegetable and egg hatchability %, egg incubation period, larval survival (%), duration (days), length and width of larvae, pupal parameters, male-female ratio, and age-specific fecundity were recorded. The results showedno statistical difference in hatchability percentages, larval duration, and pupal survival (%) in all tested vegetables. However, greater length and width of larvae were recorded when the B. cucurbitae larvae were provided with bottle gourd. Moreover, maximum pupal recovery was recorded in bottle and sponge gourd among all the tested vegetables. Maximum females were also recorded in bottle gourd. Adult longevity and fecundity were significantly affected by the host. Maximum female longevity (52 days) was recorded when B. cucurbitae were provided with bottle gourd and minimum (41 days) on sponge gourd. Similarly, maximum fecundity (823 eggs) was also recorded when maggots were fed on bottle gourd and the lowest (611 eggs) on a sponge gourd. In conclusion, Bottle gourd is the most preferable and nutritious host among all the tested vegetables and needs effective management strategies for B. cucurbitae. The output of the present studies would be helpful for the development of an effective integrated pest management (IPM) program for B. cucurbitae in a variety of vegetables.

Water Level Fluctuation Effect on Fish Reproduction Success

Alteration of water levels of the lake/reservoir due to changes in river discharges, upstream abstraction, and drawdown regulation due to hydropower generation has been reported as among the major challenges to fish physiology and ultimately reproduction. Variations in lake/reservoir water levels influence biodiversity and the abundance of lake/reservoir biota. Variations have the greatest impacts in the littoral zones hence, interfering with fish spawning, incubation, and hatching of eggs, as well as the development of larvae, postlarvae, and juveniles. This particular paper reviews the literature available on the effect of the reservoirs/lakes’ water level fluctuations on fish reproduction success using the documentary view method. The literature argues that water level fluctuations have both positive and negative impacts depending on frequency, magnitude, and duration and the species exposed. Extreme fluctuations tend to bring more adverse impacts. It further indicates that extreme and untimely water level fluctuation has direct impacts on the aquatic habitats and ultimately impacts fish assemblage and their populations. Few articles indicate the range of decrease or increase of water level, duration of such events, and effects they have on reservoir/lake ecosystem functions and fish physiology. Nevertheless, quantification of moderate and extreme water level fluctuation and associated effects is lacking. Although water level fluctuation is an important environmental cue for aquatic organisms, literature shows that the reduction of extreme water level variations especially multiannual variations is vital for fish reproduction. Therefore, upstream water use and reservoir operations should take into consideration the effects of water level fluctuations on reservoir structure, biological functions, and ultimate effects on fish reproduction.

Insect-resistant activities of Elsholtzia ciliata essential oil and its main components carvone against Tribolium castaneum in different development stages

The main objectives of the present study are to introduce a ecologically safe, and natural compound for controlling the red flour beetle, Tribolium castaneum. This study aims to thoroughly examine the effects of Elsholtzia ciliata essential oil (E. ciliata EO) and its primary components, carvone, on Tribolium castaneum eggs, larvae, pupae, and adults. The study also includes a simulated warehouse test to assess the efficacy of these substances as contact agents, fumigants, repellents, and antifeedants. All of these anti-insect activities were positively correlated with the concentrations of E. ciliata EO and carvone. Firstly, in the contact activity assay, E. ciliata EO and carvone completely inhibited the hatching of eggs and pupae of the T. castaneum at a concentration of 2.5 μL/cm2. The LC50 of E. ciliata EO and carvone were 7.62 and 4.33 μg/adult, respectively, against senior adults (5 weeks old). Secondly, in the fumigant activity assay, 60 mg/L of E. ciliata EO and carvone essentially completely inhibited pupae eclosion. On the other hand, the LD50 of E. ciliata EO and carvone against senior adults (5 weeks old) were 8.72 and 5.02 mg/L, respectively. Thirdly, for T. castaneum adults, at the highest test concentration, the repellent rate of the E. ciliata EO was above 90%. Fourthly, the larvae and adults of the T. castaneum could reach complete antifeedant activity by E. ciliata EO and carvone at the highest test concentrations. Finally, 3000 ppm of carvone was sufficient to kill all the pests in the warehouse in the simulated warehouse test. In conclusion, the results of this study will contribute to the better control of the storage pest, T. castaneum, and the development of environmentally friendly insecticides based on E. ciliata EO and carvone.

Preliminary screening of plant essential oils from an oceanic climate zone (NW Spain) for the control of equine cyathostomins

Cyathostomins (Strongylida: Cyathostominae) are gastrointestinal nematodes (GIN) that affect equines in many parts of the world. Due to anthelmintic resistance (AR), it is necessary to search for control alternatives. The objective of the study was to carry out a screening of 26 essential oils (EOs) from plants to determine in vitro their action on cyathostomins. Essential oils were obtained by hydro-distillation from leaves, flowers, fruits, and seeds of the selected species and used against the eggs of cyathostomins by means of the tests of egg hatching and larval motility inhibition. For each EO, different concentrations were prepared (250, 125, 62.5, 31.3, 15.6, 7.8, 3.9, 2.0, 1.0, 0.5 and 0.24 mg/mL). Oxfendazole at 2.5% mixed with closantel 5% was used as positive control, and PBS served as negative control. Cyathostomin eggs were obtained from feces of infected horses and infective larvae were recovered after coproculture. The in vitro test was carried out 36 h after the challenge with the EOs. The highest production of EOs was obtained from leaves of bay, eucalyptus, mallow, and basil, as well as from seeds of black pepper, coriander, cinnamon, anise, and peel of orange and cloves, cumin, and Lawson’s cypress. The oils extracted from laurel leaves, ground cinnamon, anise, cumin, and coriander seeds had a very high effect on cyathostomins eggs up to concentrations lower than 3.9 mg/mL. Therefore, in addition to the uses against other pathogens such as fungi and bacteria, some EOs might attain great importance as an alternative control strategy in the control of nematode eggs.

Natural products from Xenorhabdus and Photorhabdus show promise as biolarvicides against Aedes albopictus.

In the perpetual struggle to manage mosquito populations, there has been increasing demand for the development of biopesticides to supplant/complement current products. The insecticidal potential of Xenorhabdus and Photorhabdus has long been recognized and is of interest for the control of important mosquitoes like Aedes albopictus which vectors over 20 different arboviruses of global public health concern. The larvicidal effects of cell-free supernatants, cell growth cultures and cell mass of an extensive list of Xenorhabdus and Photorhabdus spp. was investigated. They were quite effective against Ae. albopictus causing larval mortality ranging between 52-100%. Three Photorhabdus spp. and 13 Xenorhabdus spp. release larvicidal compounds in cell-free supernatants. Cell growth culture of all tested species exhibited larvicidal activity, except for Xenorhabdus sp. TS4. Twenty-one Xenorhabdus and Photorhabdus bacterial cells (pellet) exhibited oral toxicity (59-91%) against exposed larvae. The effect of bacterial supernatants on the mosquito eggs were also assessed. Bacterial supernatants inhibited the hatching of mosquito eggs; when unhatched eggs were transferred to clean water, they all hatched. Using the easyPACId approach, the larvicidal compounds in bacterial supernatant were identified as fabclavine from X. szentirmaii and xencoumacin from X. nematophila (causing 98 and 70% mortality, respectively, after 48 h). Xenorhabdus cabanillasii and X. hominickii fabclavines were as effective as commercial Bacillus thuringiensis subsp. israelensis and spinosad products within 5 days post-application (dpa). Fabclavine and xenocoumacin can be developed into novel biolarvicides, can be used as a model to synthesize other compounds or/and can be combined with other commercial biolarvicides. © 2024 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Comprehensive analysis of Mentha longifolia subsp. himalaiensis essential oil: GC MS profiling and biological properties

Mentha longifolia is a well-known species of medicinal plant for its ethnopharmacological, pharmacological importance, industrial uses etc. This research paper presents a comprehensive study on a new species Mentha longifolia subsp. himalaiensis essential oil, focusing on its GC-MS analysis, nematicidal and antioxidant activities, as well as in-silico PASS prediction. The essential oil was extracted from Mentha longifolia subsp. himalaiensis leaves using steam distillation and subjected to gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis to identify its chemical composition. The in vitro nematicidal activities were accessed via nematode mortality assay and nematode egg hatching assay against Meloidogyne incognita. The essential oil was also tested for its antioxidant activities via DPPH (2,2-diphenyl-2-picrylhydrazyl) radical scavenging activity, H2O2 (Hydrogen peroxide) scavenging activity and Metal chelating activity. The essential oil was also tested for antimicrobial potential against 5 strains of bacteria and two strains of fungus. Furthermore, the major chemical constituents of the essential oils were subjected to in-silico PASS prediction for their biological activities. The GC and GC-MS analysis revealed that piperitenone oxide (31.13 %) and cis-piperitone oxide (51.61 %) were the major components of the essential oil. The essential oil exhibited significant nematicidal activity against M. incognita and notable antioxidant activity. The essential oils also showed significant antibacterial and antifungal activity against targeted microbial strains. In-silico PASS prediction further supported the essential oil's bioactive properties and its potential for diverse applications. These results highlight the potential of Mentha longifolia subsp. himalaiensis essential oil as a natural nematicide, antimicrobial and antioxidant agent.

A 6 year assessment of low sea-ice impacts on emperor penguins

Sea ice, and particularly land-fast sea ice, is crucial for emperor penguins as a breeding and moulting platform and foraging habitat (Barbraud &amp; Weimerskirch 2001). Emperor penguins use land-fast sea ice as a breeding platform to raise their chicks, from egg hatching in late July to mid-August until fledging, typically between mid-December and early January.