Insect responses to seasonal time constraints under global change are facilitated by warming and counteracted by invasive alien predators.

In seasonal environments, organisms with complex life cycles not only contend with seasonal time constraints (TC) but also increasingly face global change stressors that may interfere with responses to TC. Here, we tested how warming and predator stress imposed during the egg and larval stages shaped life history and behavioural responses to TC in the temperate damselfly Ischnura elegans. Eggs from early and late clutches in the season were subjected to ambient and 4 °C warming temperature and the presence or absence of predator cues from perch and signal crayfish. After hatching, larvae were retained at the same thermal regime, and the predator treatment was continued or not up to emergence. The late eggs decreased their development time, especially under warming and when not exposed to predator cues. However, the late eggs increased their development time when exposed to predator cues, especially to crayfish cues. The TC decreased survival of late larvae that were as eggs exposed to crayfish cues, indicating a carry-over effect. The TC and warming additively reduced late larvae development time to emergence. Independent of the TC, predator cue effects on development time were stronger during the egg than during the larval stage. The late individuals expressed lower mass at emergence, which mirrored the size difference between field-collected mothers. Warming caused a higher mass at emergence. The late individuals increased their boldness and showed a higher number of moves, whereas warming caused a decreased boldness. There was no predator cue effect on larval behaviour. The results indicate that late individuals compensate for late season egg laying, which is facilitated under warming but counteracted under predation risk, especially when imposed by the crayfish.

Oviposition behavior of the parasitoid Telenomus remus (Hymenoptera: Scelionidae) on eggs of Spodoptera frugiperda (Lepidoptera: Noctuidae).

Telenomus remus (Hymenoptera: Scelionidae) is an efficient parasitoid of Spodoptera eggs. However, biological control programs require taxonomic, bioecological and behavioral studies of biological agents. Although the performance of T. remus in pest control has been evaluated, little is known about its behavioral aspects that can influence IPM tactics. The aim of this study was therefore to study the parameters related to the oviposition behavior of T. remus on Spodoptera frugiperda (Lepidoptera: Noctuidae) eggs. The experiment was conducted in the laboratory, where 17 females were transferred individually to arenas containing a mass of S. frugiperda eggs. Oviposition behavior was recorded for 30 minutes. The average walking speed of the females was 0.116 mm.s-1 and the total distance covered was 203.3 mm. The females remained on the egg masses for an average of 16.7 min, which corresponds to more than half of the total time. The average number of parasitized eggs was 15.1 per female in 30 minutes. Females with larger antennae had lower values for average speed and total distance covered. The results of the parameters evaluated show the standard oviposition behavior of T. remus females on S. frugiperda eggs and help us to better understand the species.

The effect of addition of calcium mineral in feed containing fishery wastes on egg production and hatching performance of Mojosari ducks.

Calcium (Ca) is an essential mineral for eggshell formation and muscle contraction, and a lack of it can result in poor egg quality and decreased egg output in laying ducks. This study aims to see how feeding the mineral Ca in a ration containing Shrimp head meal and Bilis fish head affects the laying performance and quality of hatching eggs in Mojosari ducks. A total of 105 female and 15 male Mojosari ducks, aged 78 weeks, were raised for three months and randomly divided into 15 flocks (each flock containing seven females and one male duck). There were three kinds of treatment, namely P0 (control, without mineral), P1 (ratio of Shrimp head meal and Bilis fish head 2:1 + 1% mineral), and P2 ((ratio of Shrimp head meal and Bilis fish head 1:2 + 1% mineral). The findings revealed that adding mineral Ca to feed, including Shrimp head meal and Bilis fish head, had no significant influence (P>0.05) on laying Mojosari duck performance in terms of feed intake, egg production, egg weight, egg quality, ducklings produced, and income over feed cost (IOFC). Furthermore, Ca addition in the ration did not result in substantial increases (P>0.05) in fertility, hatchability, or egg size characteristics. Based on the findings of this study, feeding ducks with shrimp head meal and Bilis fish head can be used as an alternate calcium-free feed formulation.

Finding a balance: Reproductive trade-offs in parasitic isopods of the family Cymothoidae.

In this study conducted along the coast of Odisha, India, reproductive trade-offs in isopods of the family Cymothoidae were investigated, focusing on the relationship between the number vs. volume of eggs and the percentage of brood to body volume. Ovigerous females from species with substantial sample sizes (n > 30) were analyzed to understand their survival strategies. The findings highlight distinct strategies among different parasite types within Cymothoidae. Buccal parasites such as Cymothoa frontalis and Cymothoa indica, along with branchial parasites like Joryma sawayah and Agarna malayi, generally produced a higher number of smaller eggs, except for A. malayi, which produced fewer but larger eggs. In contrast, the external body surface-attaching parasite, Nerocila orbignyi, was observed to produce fewer eggs of larger size. Across all parasite types (intraspecific), there was a statistically significant negative correlation between egg number and egg volume (p < 0.05). Buccal parasites were observed to have the highest percentage of marsupium volume relative to body volume, indicating a strategy to maximize egg storage. Conversely, external body surface-attaching parasites had the lowest percentage, possibly reflecting adaptation to a different reproductive environment. Additional observations revealed anatomical adaptations in all the studied isopod species which include the shift of the alimentary canal to the dorsal side to accommodate the development of the marsupial sac for egg incubation. In summary, these findings illustrate how parasitic isopods of the family Cymothoidae manage trade-offs between reproductive potential and success, crucial for their species' continuity and survival strategies in coastal ecosystems.

Measuring protein stoichiometry with single-molecule imaging in Xenopus egg extracts.

In human cells, DNA double-strand breaks are rapidly bound by the highly abundant non-homologous end joining (NHEJ) factor Ku70/Ku80 (Ku). Cellular imaging and structural data revealed a single Ku molecule is bound to a free DNA end and yet the mechanism regulating Ku remains unclear. Here, we describe how to utilize the cell-free Xenopus laevis egg extract system in conjunction with single-molecule microscopy to investigate regulation of Ku stoichiometry during non-homologous end joining. Egg extract is an excellent model system to study DNA repair as it contains the soluble proteome including core and accessory NHEJ factors, and efficiently repairs double-strand breaks in an NHEJ-dependent manner. To examine the Ku stoichiometry in the extract system, we developed a single-molecule photobleaching assay, which reports on the number of stable associated Ku molecules by monitoring the intensity of fluorescently labeled Ku molecules bound to double-stranded DNA over time. Photobleaching is distinguishable as step decreases in fluorescence intensity and the number of photobleaching events indicate fluorophore stoichiometry. In this paper we describe sample preparation, experimental methodology, and data analysis to discern Ku stoichiometry and the regulatory mechanism controlling its loading. These approaches can be readily adopted to determine stoichiometry of molecular factors within other macromolecular complexes.

Demography and predatory potential of Orius strigicollis on eggs of Plutella xylostella at two temperatures.

Background: The polyphagous predatory bug Orius strigicollis Poppius (Heteroptera: Anthocoridae) is an active predator used to control many insect pests of agricultural crops. Orius species are significantly affected by the type of food and temperature. Method: A study of O. strigicollis feeding on Plutella xylostella L. (Lepidoptera: Plutellidae) eggs in climate chambers at 28 and 32 °C, 70 ± 5% relative humidity, 16:8 photoperiod, was conducted to determine the effects of different temperatures on the predation activity, biological characteristics and demographic parameters of O. strigicollis. Twosex-MS Charts were used to determine the age-stages and characteristics of this species. Results: The results showed that the daily consumption of pre-adults on eggs of P. xylostella was highest at 28 °C, and at this temperature, there was a greater probability that O. strigicollis would survive to adulthood (42.5%) than at 32 °C (25.0%). It has also been found that at 28 °C there was a long oviposition period (9.38 days) and the greatest female fecundity (44.2 eggs/female) In addition to the highest life expectancy of O. strigicollis (16.96 days) at 28 °C, the intrinsic rate of increase (0.087 d-1) was also highest. According to our results, O. strigicollis has the potential to grow and develop on the eggs of P. xylostella at 28 °C and, therefore, could potentially be used as a biological control agent in integrated pest management (IPM) programs.

Immunomodulatory effect of Dicrocoelium dendriticum ova on DSS-induced experimental colitis in C57BL/6 mouse.

Inflammatory bowel disease (IBD) significantly diminishes an individual's quality of life and increases the risk of colorectal cancer. Recent clinical and experimental findings suggest that infection with parasitic helminths may suppress the development of certain inflammatory conditions. The objective of this study was to evaluate the immunoregulatory effects of Dicrocoelium eggs on experimentally induced colitis in C57BL/6 mice using dextran sulfate sodium (DSS). C57BL/6 mice received 3.5% DSS orally for 7 days to induce colitis, during which they were treated intraperitoneally with Dicrocoelium eggs. The severity of colitis was assessed through parameters such as body weight, stool consistency or bleeding, disease activity index (DAI), colon lengths, macroscopic scores, histopathological findings, colon gene expression levels, and serum cytokine levels. Our results indicated that Dicrocoelium eggs administration significantly reduced the severity of colitis and disease activity. Histopathological scores improved, correlating with downregulation of IFN-γ and upregulation of IL-4 expression. This findings suggest the therapeutic potential of Dicrocoelium eggs in treating colitis. Immunotherapy involving Dicrocoelium eggs primarily induces a Th2 response and modulates IFN-γ, contributing to reduced inflammation in colitis. Thus, this approach could be a promising therapeutic strategy for alleviating inflammation in IBD.

Low microbial abundance and community diversity in the egg capsule of the oviparous cloudy catshark (Scyliorhinus torazame) during oviposition.

Vertebrate embryos are protected from bacterial infection by various maternally derived factors, yet little is known about the defence mechanisms in elasmobranchs. This study aimed to characterize the intracapsular environment of freshly laid eggs of the oviparous catshark (Scyliorhinus torazame) by investigating the microbial abundance and microbiota to understand its potential contribution to embryonic defence. The egg capsule of oviparous elasmobranchs is tightly sealed until pre-hatching, after which seawater flows into the capsule, exposing the embryos to the surrounding seawater. We found that early embryos were highly vulnerable to environmental pathogens, suggesting that the embryos are somehow protected from infection before pre-hatching. Indeed, the intracapsular environment of freshly laid eggs exhibited significantly low bacterial density, maintained until pre-hatching. Furthermore, the microbiome inside eggs just after oviposition differed markedly from those of rearing seawater and adult oviducal gland epithelia; these eggs were predominantly populated by an unidentified genus of Sphingomonadaceae. Overall, this study provides compelling evidence that early embryos of oviparous cloudy catshark are incubated in a clean intracapsular environment that potentially plays a significant role in embryonic development in oviparous elasmobranchs.

Methylome profile of medaka eggs and sperm.

Eggs and sperm are responsible for the continuation of generations. Following the epigenetic reprogramming of the embryo, core epigenetic information present in the sperm and eggs is transmitted to offspring somatic cells prior to the blastula stage, which specifically influences gene expression in the cells. Differences in the patterns of DNA methylation between the paternal and maternal genomes are critical to regulating allele-specific gene expression in the developing embryo, constituting the basis of genomic imprinting in mammals. While the information on allele-specific epigenetic information has been limited to mammals, it is not clearly understood whether non-mammalian vertebrate gametes possess any sex-specific allelic epigenetic information and whether somatic cells maintain the allele-specific epigenetic information, particularly DNA methylation. To determine the landscape of DNA methylation in paternal and maternal alleles in a non-mammalian vertebrate, we profiled the methylome of egg in medaka fish and compared it with our previously published medaka sperm methylome. We identified a set of gamete-specific differentially methylated regions (DMRs) in the genome- medaka eggs maintained a significantly lower global methylation profile than the sperm. Based on our sequencing depth and data, 10 DMRs were hypermethylated, and 237 DMRs were hypomethylated in the eggs compared to the sperm methylome. Somatic cells in blastula maintained some of those parental gamete-specific DNA methylation profiles. Those DMRs are associated with 70 genes, suggesting that they may have imprinted-like functions and warrant further investigation.

Passive dispersal potential of medaka eggs by attaching to waterbirds.

Colonization of new habitats is a key event in forming current distributions in organisms. It has been speculated that freshwater fish eggs can be dispersed passively by attaching to or egestion from waterbirds that arrive in wetland habitats. Recent research showed that some freshwater fish eggs could be excreted alive from birds and then successfully hatch, but scientific evidence of bird-mediated fish dispersal is still limited to endozoochory (internal transport through a bird's digestive tract). Here, we experimentally suggest the dispersal potential in another way or epizoochory (external dispersal by attaching to waterbirds), using medaka Oryzias latipes, which spawns on aquatic plants. Our field experiment showed that waterbirds could carry artificial aquatic plants among waterbodies. Medaka eggs attached to aquatic plants could survive in the air for up to 18 h with a median lethal period of 16.3 h. Those two findings raise the possibility of the epizoochory of medaka in nature.

Liver Fibrosis Is Enhanced by a Higher Egg Burden in Younger Mice Infected with S. mansoni.

Schistosomiasis affects over 250 million people worldwide, with the highest prevalence at the age of 10-14 years. The influence of the host's age on the severity of liver damage is unclear. We infected male 8, 14, and 20-week-old mice with S. mansoni. Hepatic damage, inflammation, fibrosis, and metabolism were analyzed by RT-qPCR, Western blotting, ELISA, immunohistochemistry, and mechanistic transwell chamber experiments using S. mansoni eggs and human hepatic stellate cells (HSCs) or primary mouse hepatocytes. Major results were validated in human biopsies. We found that hepatosplenomegaly, granuloma size, egg load, inflammation, fibrosis, and glycogen stores all improved with the increasing age of the host. However, serum alanine transaminase (ALT) levels were lowest in young mice infected with S. mansoni. Hepatic carbohydrate exploitation was characterized by a shift towards Warburg-like glycolysis in S. mansoni-infected animals. Notably, S. mansoni eggs stimulated hepatic stellate cells to an alternatively activated phenotype (GFAP+/desmin+/αSMA-) that secretes IL-6 and MCP-1. The reduction of fibrosis in older age likely depends on the fine-tuning of regulatory and inflammatory cytokines, alternative HSC activation, and the age-dependent preservation of hepatic energy stores. The current results emphasize the significance of investigations on the clinical relevance of host age-dependent liver damage in patients with schistosomiasis.

Effects of dietary digestible lysine levels in breeding Japanese quails on productive and reproductive performance, egg quality, blood metabolites and immune responses.

BACKGROUND: The vegetable-based diet alone does not provide the lysine (Lys) needed to maximize poultry productive performance. OBJECTIVES: This experiment aimed to evaluate the effects of dietary digestible Lys (dLys) level on productive and reproductive performance, egg quality, blood metabolites and immune responses in breeding Japanese quails (Coturnix japonica). METHODS: The experiment was conducted in a completely randomized design with 6 treatments, 5 replicates and 15 (12 females and 3 meals) 10-week-old breeding Japanese quails each. A basal diet was formulated to meet nutritional requirements of breeding quails except dLys. The basal diet was supplemented with graded (+0.82 g/kg) levels of l-Lys-HCl, corresponding to dietary dLys levels of 0.690%, 0.755%, 0.820%, 0.885%, 0.950% and 1.015%. The experiment lasted for 12 weeks, which was divided into 3-4-week periods. RESULTS: Significant differences were observed for egg production (EP), egg mass (EM) and feed efficiency (FE) in response to increasing dietary dLys concentration with quadratic trends. The highest traits were observed in the birds fed with a diet containing 0.885% dLys. However, feed intake, egg quality, reproductive performance, blood metabolites and immune responses against sheep red blood cell inoculation were not significantly affected by increasing dietary dLys concentrations. The dLys requirements during 11-14, 15-18, 19-22 and 11-22 (overall) weeks of age for optimal EP, EM and FE, based on the quadratic broken-line regression analysis, were estimated 272, 265, 250 and 266; 293, 285, 264 and 279; and 303, 294, 281 and 293 mg/bird/day, respectively. CONCLUSIONS: The dLys requirements vary depending on the EP phase and the trait being optimized. The estimated dLys requirement for FE was higher than those for EP and EM. During the peak stage of the first laying cycle, the dietary dLys level of 0.932% and a daily intake of 303 mg dLys/bird are sufficient for optimal performance.

In ovo betaine and heat acclimation affect hatching results, growth performance and immunity of the broilers under cyclic heat stress.

This study investigated the effects of in ovo betaine and thermal manipulation during incubation on growth performance, and some immune parameters of broilers under cyclic heat stress (CHS). Eggs were divided into 5 groups and incubated at 1) 37.8 °C and 60% relative humidity (Control incubation and not-injected, CI); 2) eggs were incubated at CI and in ovo betaine injected into yolk sac on d 11 (E11) (CI + In ovo); 3) eggs were exposed to 38.8 °C for 8 h between 10 and 18d of incubation (heat acclimation, HA); 4) eggs were incubated at HA and in ovo betaine applied (HA + In ovo); 5) positive control: eggs were incubated at CI and injected with saline. Hatched chicks were raised under standard management conditions until 21 d, between 21 and 42 d half of the chickens in each incubation treatment were kept either at optimum (OPT) or at CHS. In ovo and HA did not affect hatching performance. In ovo increased thymus and spleen weights of chicks. Serum IgG was higher in HA + In ovo chicks. From d 7 to 21, in ovo chicks were heavier body weights, consumed more feed, and better feed conversion than those from CI. The body weights of HA chickens were similar in OPT and CHS on d 28 and 35. CHS reduced the body weight of CI chickens which was compatible with their feed consumption. Moreover, feed intake of HA + In ovo chickens exposed to CHS was higher than those not injected indicating that HA + In ovo enhanced thermoregulation of chickens under CHS.

Egg Drop Syndrome 76 in a U.S. Broiler Breeder Flock.

A four-house broiler breeder farm of approximately 35-wk-old hens was diagnosed with egg drop syndrome (EDS'76) utilizing PCR and hemagglutination inhibition (HI) testing. Based on communication with local practitioners, the geographic area near where this flock was located had numerous EDS'76 cases in table egg layers at the time of diagnosis. An egg production drop was seen in the broiler breeder flock over a 7-day period, which prompted an investigation. During this investigation, a significant number of shell-less, wrinkled, and pale eggs were noted, but no increases in mortality or respiratory signs were observed. The disease and subsequent production drops spread horizontally across the farm over a 5-wk period. Production returned to approximately the breed standard egg production 4 wk after initial egg production drop. However, hatching egg utilization continued to be reduced for another 2 wk because of the number of thin-shelled eggs. A similar pattern of drop in egg production and subsequent return was observed in the other houses. No significant lesions were noted in the tissues submitted for histopathology. Differential diagnoses that could cause shell abnormalities and egg production drops were ruled out by submitting appropriate samples for diagnostic investigation. Egg drop syndrome 76 PCR was performed on shell-less eggs and EDS'76 was detected by PCR at two separate laboratories. Subsequently, serum was submitted for HI and positive results were found in each house as they showed egg production drop concurrent with shell abnormalities. At the time the flocks returned to breed standard production, EDS'76 titers were consistent with a uniformly exposed and seroconverted flock. The authors suspect that immunosuppression as pullets played a role in this flock being impacted by EDS. No other farms in the company's system were observed with production drops or shell abnormalities similar to this case.

Reporte de caso- Síndrome de baja de postura 76 en una parvada de reproductoras de pollos de engorde en los Estados Unidos. Una granja de reproductoras pesadas con cuatro casetas con aves de aproximadamente 35 semanas de edad fue diagnosticada con el síndrome de baja de postura 76 (EDS'76) mediante PCR y pruebas de inhibición de hemaglutinación. Según las comunicaciones con los profesionales locales, el área geográfica cercana a donde se encontraba esta parvada tenía numerosos casos de síndrome de baja de postura 76 en aves de postura de huevo comercial en el momento del diagnóstico. Se observó una caída en la producción de huevo en la parvada de reproductoras pesadas durante un período de siete días, lo que motivó una investigación. Durante esta investigación, se observó una cantidad significativa de huevos sin cascarón, con cascarón rugoso, y pálidos, pero no se observaron aumentos en la mortalidad ni en signos respiratorios. La enfermedad y las consiguientes caídas de producción se extendieron horizontalmente por toda la granja durante un período de cinco semanas. La producción retornó aproximadamente a la producción de huevos estándar de la estirpe de cuatro semanas después de la estirpe cuatro semanas después de la caída inicial en la producción de huevo. Sin embargo, la utilización de huevos para incubar continuó reduciéndose durante otras dos semanas debido a la cantidad de huevos de cascarón delgado. En las otras casetas se observó un patrón similar de caída en la producción de huevos y posterior retorno. No se observaron lesiones significativas en los tejidos enviados para histopatología. Se descartaron diagnósticos diferenciales que pudieran provocar anomalías en el cascarón y caídas en la producción de huevo, mediante el envío de muestras adecuadas para investigación diagnóstica. Métodos de PCR para el síndrome de baja de postura 76 se llevaron a cabo en huevos sin cascarón y el síndrome de baja de postura 76 se detectó mediante PCR en dos laboratorios diferentes. Posteriormente, se envió suero para inhibición de la hemaglutinación y se encontraron resultados positivos en cada caseta ya que mostraron una caída en la producción de huevo junto con anomalías en el cascarón. En el momento en que las parvadas volvieron a reproducir la producción estándar, los títulos de anticuerpos contra el síndrome de baja de postura 76 eran consistentes con una parvada uniformemente expuesta y con seroconversión. Los autores sospechan que la inmunosupresión en las pollitas jugó un papel en el impacto del síndrome de baja de postura en esta parvada. No se observaron otras granjas en el sistema de la compañía con caídas de producción o anomalías en el cascarón similares a este caso.

Design, Synthesis, and 3D-QASR of Oxazoline Derivatives Containing an S-S Moiety as Potential Acaricide.

To mitigate the detrimental effects of agricultural pest mites on crop yield, an active substructure splicing strategy was employed to modify etoxazole by introducing an S-S moiety. The target products were obtained efficiently via a bilateral disulfurating reagent (DSMO), which was developed by our group. The leaf dip method was used to evaluate the activities of the designed target compounds against the eggs and larvae of the spider mite (Tetranychus cinnabarinus). Most of the target compounds exhibited good efficacy in controlling the larvae and eggs of T. cinnabarinus. Based on these results, a three-dimensional quantitative structure-activity relationship (3D-QSAR) model was established to guide the construction of compound 7l. Notably, compound 7l exhibited a better activity against T. cinnabarinus eggs (LC50 = 0.0035 mg/L) compared to etoxazole (LC50 = 0.2990 mg/L). Greenhouse bioassays indicated that compound 7l exhibits excellent acaricidal activity against egg of T. cinnabarinus, which is better than the etoxazole at 1.0 mg/L. Additionally, some of the compounds showed inhibitory effects against Dickeya zeae (D. zeae), Xanthomonas campestris pv campestris (Xcc), Xanthomonas oryzae pvoryza (Xoo), and Xanthomonas oryzae pvoryzicola (Xoc). Furthermore, compounds 7l not only exhibited relatively potent against Plutella xylostella activities (LC50 = 24.0 mg/L) but also had low toxicity (LC50 > 11.0 µg/bee) to Apis mellifera. In conclusion, the current experimental results suggest that oxazoline derivatives containing an S-S moiety have the potential to serve as lead compounds for the development of novel acaricide agents.

Breeding stages affect egg recognition in azure-winged magpies (Cyanopica cyanus).

Egg rejection often involves a cognitive process of recognizing foreign eggs, which can vary not only between species or among different individuals of the same species, but also within the same individual during different breeding stages, leading to markedly different responses to parasitic eggs. We conducted a comparative study in Wuhan, Hubei, and Fusong, Jilin, China, on the recognition and rejection behavior of azure-winged magpies (Cyanopica cyanus) at different breeding stages (pre-egg-laying, one-host-egg, multi-host-egg and early incubation stages). In the Fusong population, there was a significant difference in the rejection rate of model eggs by azure-winged magpies at different stages of the egg-laying period. During the one-host-egg stage, the rejection rate (63.6%) was significantly lower than that during the pre-egg-laying stage (85.7%) and the multi-host-egg stage (100%). The population of azure-winged magpies in Wuhan exhibited a 100% rejection rate towards model eggs during the pre-egg-laying stage. Furthermore, during the incubation stage, azure-winged magpies were able to accurately recognize and reject foreign eggs even when those were in majority. This indicates that azure-winged magpies employ a template-based recognition mechanism rather than relying on discordance mechanism for recognition after the onset of incubation. This study suggests that while azure-winged magpies can truly recognize their own eggs, different breeding stages still influence their rejection response towards parasitic eggs, especially during the pre-egg-laying and egg laying stages.

Maternal genetic variants in kinesin motor domains prematurely increase egg aneuploidy.

The female reproductive lifespan is highly dependent on egg quality, especially the presence of a normal number of chromosomes in an egg, known as euploidy. Mistakes in meiosis leading to egg aneuploidy are frequent in humans. Yet, knowledge of the precise genetic landscape that causes egg aneuploidy in women is limited, as phenotypic data on the frequency of human egg aneuploidy are difficult to obtain and therefore absent in public genetic datasets. Here, we identify genetic determinants of reproductive aging via egg aneuploidy in women using a biobank of individual maternal exomes linked with maternal age and embryonic aneuploidy data. Using the exome data, we identified 404 genes bearing variants enriched in individuals with pathologically elevated egg aneuploidy rates. Analysis of the gene ontology and protein-protein interaction network implicated genes encoding the kinesin protein family in egg aneuploidy. We interrogate the causal relationship of the human variants within candidate kinesin genes via experimental perturbations and demonstrate that motor domain variants increase aneuploidy in mouse oocytes. Finally, using a knock-in mouse model, we validate that a specific variant in kinesin KIF18A accelerates reproductive aging and diminishes fertility. These findings reveal additional functional mechanisms of reproductive aging and shed light on how genetic variation underlies individual heterogeneity in the female reproductive lifespan, which might be leveraged to predict reproductive longevity. Together, these results lay the groundwork for the noninvasive biomarkers for egg quality, a first step toward personalized fertility medicine.

DNA barcode reference library of the fish larvae and eggs of the South China Sea: taxonomic effectiveness and geographic structure.

Fish early-stages constitute useful indicators of the states of marine ecosystems, as well as important fishery resources. Given the spectacular phenotypic changes during ontogeny, and the paucity of diagnostic morphological characters at the species level, the identification of fish early-stages is a challenging task. DNA barcoding, the use of the mitochondrial gene of the cytochrome c oxidase subunit I (COI) as an internal species tag, opened new perspectives for the identifications of both larval fish and fish eggs. However, the accuracy of the identifications assisted by DNA barcoding are dependent of the completeness of the DNA barcode reference libraries used to assigned unknown sequences to known species. Here, we built a DNA barcode reference library for 113 species of larval fish and 85 species of fish eggs involving the production of 741 newly generated DNA barcodes from South China Sea (63 localities). Together with 514 DNA barcodes mined from Genbank for 116 species from the South China Sea regions, a reference library including 1255 DNA barcodes for 308 species (248 locations) was assembled. The present study emphasizes the importance of integrating DNA barcoding to large scale inventories of early stages, as DNA-based species delimitation analyses delimited 305 molecular operational taxonomic units (MOTUs) and multiple cases of discordance with morphological identifications were detected. Cryptic diversity is detected with 14 species displaying two MOTUs and a total of 23 species were lumped into 11 MOTUs due to low interspecific divergence and/or mixed lineages.

Biochemical analysis and fertilization success of Cirrhinus mrigala ova during induced spawning.

Fish egg quality is very crucial in aquaculture sector for production of healthy seed. Egg yolk is an energy reservoir for growth and development of embryo. This study evaluated the biochemical composition and quality of Cirrhinus mrigala eggs at three different hatchery sites of Pakistan, (Site 1= Fish Seed Hatchery, District Pakpattan; Site 2= Sidhuwan Hatchery, Head Balloki, District Kasur; Site 3= Chenab Fish Hatchery, Rangpur, District Muzaffargarh) during induced breeding. For this, a total of 36 (18 males and 18 females) fish brooders, 12 (06 males and 06 females) from each site were utilized. Fatty acids analysis revealed significant differences among three different sites. Saturated fatty acids i.e., palmitic acid (C16:0) and stearic acids (C18:0) were higher at site 2 compared to the others sites. Monounsaturated fatty acids i.e., Oleic acid (C18:1) and polyunsaturated fatty acids i.e., Docosahexaenoic acid (DHA) (C22:6) exhibited considerably greater values at site 2 than those of other two sites. Egg mineral contents unveiled remarkable differences, particularly at site 2 indicating significantly higher mineral contents except copper (Cu) in comparison to the other sites. Significant variation exists in fertilization and hatching rates during induced spawning, with the highest values recorded at site 2. It is concluded that biochemical composition of egg especially fatty acid profile and mineral content greatly influences the embryonic development and hatching success of farm reared Cirrhinus mrigala.

AI reveals how sperm sticks to egg during fertilization.

Two studies use software developed by some of this year's Nobel winners to find elusive protein complex.