Laboratory Populations Research Articles

Bugs (hemiptera) of western siberia possible agents of biological control of phytophages

The increasing harmfulness of phytophages damaging agricultural and ornamental crops is associated with various factors, in particular with the expansion of the range of pest species and the development of resistance to the chemical plant protection products used. The search and regular replenishment of the assortment of entomocarifages is becoming important in the biological protection of plants for obtaining organic crop products. An alternative to using chemical pesticides is to use natural enemies. One of the promising and numerous suborders is the hemiptera or bugs (Hemiptera: Heteroptera). The paper provides an ecological and faunal description of zoophages and zoophytophages of the order Hemiptera found in the regions of the Novosibirsk region (Moshkovsky, Bolotninsky, Chulymsky districts), Altai Territory (Troitsky district) and the Altai Republic (Ust-Koksinsky district) during the growing season of 2023. Seven species belonging to three families of the bedbug suborder were collected: Nabidae (Nabis ferus, Nabis limbatus), Anthocoridae (Orius niger), Pentatomidae (Arma custos, Zicrona caerulea, Picromerus bidens, Pentatoma rufipes). The insects were kept alive for transportation to the laboratory and study of their biological characteristics. Three species were introduced into laboratory culture. The selection of conditions for keeping predatory insectoids continues to obtain a stable laboratory population and further use in crop production. As a result of the surveys of natural and agrobiocenoses, predation by Arma custos and Pentatoma rufipes on the larvae of the Colorado potato beetle was revealed.

B-118 Comparison of Statistical Methods, Chauvenet Test, and Interquartile Deviation for Urinary Sediment Inter Microscopists Evaluation

Abstract Background Comparison among microscopists is a quality process aimed at achieving comparability of analyses among collaborators who perform microscopy or manual analysis examinations, as in the case of urinary sediment examination. The current laboratory process evaluates red blood cell and white blood cell counts among microscopists within the same unit, aiming to identify discrepant counts through the application of statistical tools, with Chauvenet Statistics and Interquartile Deviation (IQD) being the most common in the literature. The purpose was to systematically compare Chauvenet Statistics and IQD as evaluation criteria for the comparison among microscopists for urinary sediment examination in our laboratories. Methods A total of 45 laboratory units within a total of 684 participants were analyzed throughout 2023. The results reported by microscopists from the same unit were evaluated using Chauvenet Statistics and IQD, calculating the adequacy rate for each type of assessment. Results Adopting IQD as the evaluation criterion, adequacy rates of 94.20% for red blood cell counts and 93.73% for white blood cell counts were observed. Using Chauvenet Statistics, the adequacy rates were 96.20% for red blood cells and 95.65% for white blood cells. This difference stems from 233 results identified as inadequate by the IQD method but deemed adequate by Chauvenet Statistics. In these cases, the results did not exhibit a normal distribution, approaching an expected distribution for categorical (discrete) variables. Additionally, 35 results identified as inadequate by Chauvenet Statistics were evaluated as adequate by the IQD method. These occurrences were observed when the reported results approached a normal distribution. Conclusions Regarding Chauvenet Statistics, IQD is a more efficient statistical tool for use as an evaluation criterion in the comparison among microscopists who perform red and white blood cell counts for urinary sediment examination in the selected laboratory units. However, the present study illustrated that each of the statistical tools will be more efficient in identifying outliers depending on the dataset analyzed. Therefore, it is important to consider the laboratory's epidemiology and population to decide which statistical tool is most suitable for each scenario.

A-201 The Impact of Implementing the CKD-EPI 2021 Equation for Calculation of Estimated Glomerular Filtration Rate (eGFR) and the Kidney Failure Risk Equation (KFRE) on a Large Community Laboratory Population

Abstract Background Community laboratories in Ontario, Canada have reported estimated glomerular filtration rate (eGFR) using the CKD-EPI 2009 equation without race adjustment since 2020. In 2023, the Canadian Society of Nephrology recommended implementation of the CKD-EPI 2021 equation for eGFR, which does not incorporate a race-based modifier. Community laboratories will also report the 5-year Kidney Failure Risk Equation (KFRE), a risk prediction model to estimate the risk of renal failure in people with chronic kidney disease (CKD) Stages 3 to 5 (eGFR <60 mL/min/1.73m2), which is more accurate than judging by eGFR alone. This study assessed the impact of implementing the CKD-EPI 2021 equation for eGFR and the 5-year KFRE in a large community laboratory population. Methods Laboratory results for serum creatinine and urine albumin to creatinine ratio (ACR), patient sex and age were extracted from Dynacare’s laboratory information system for November 2023. The CKD-EPI 2009 without race adjustment and the CKD-EPI 2021 were calculated. Reclassification of CKD stage using the CKD-EPI 2021 equation was assessed. The 4-variable 5-year KFRE was calculated for patients in CKD Stage 3-5 (eGFR <60 mL/min/1.73m2) when all parameters including, patient age, sex, creatinine and ACR, were available. Results Data was extracted for 242,843 patients. The median age was 61 years old and 47% of the population was female. The calculated median eGFR was 83 and 87 mL/min/1.73m2 when the CKD-EPI 2009 with no race adjustment, and CKD-EPI 2021 equation, respectively, were applied. Linear regression analysis showed a correlation of 0.997 with a slope of 0.990 and y-intercept of 4.513. A total of 13.0% (n=31,679) of patients were reclassified into a less progressive CKD stage when the CKD-EPI 2021 was applied compared to the CKD-EPI 2009 without race adjustment. Notable, was the reclassification of 21.8% (n=6899) of those patients from Stage 3a to 2, i.e. patients no longer have CKD (eGFR >60 mL/min/1.73m2) based on the new calculation. 64.8% (n=20513) of patients were reclassified from Stage 2 to 1, 9.4% (n=2977) were reclassified from Stage 3b to 3a, 3.5% (n=1102) were classified from Stage 4 to 3b, and 0.6% (n=188) were reclassified from Stage 5 to 4. The 5-year KFRE was calculated when creatinine and ACR were included on the same order and the patient was classified as Stage 3 to 5 (n=12,737 patients with eGFR <60 mL/min/1.73m2). The 5-year KFRE showed increasing median risk, 1%, 4%, 27%, 95%, as CKD stage increased from 3a, 3b, 4 and 5, respectively. 1.1% (n=58) of patients in Stage 3a, 43.3% (n=1584) of patients in Stage 3b, 96.6% (n=1994) of patients in Stage 4, and 100% (n=401) of patients in Stage 5 met the KFRE threshold of ≥5% for referral to nephrology. Conclusions Implementation of the CKD-EPI 2021 resulted in reclassification to a less progressive CKD stage. Use of the KFRE as a clinical decision tool will increase patient referral to nephrology. This study provided insight into the impact of the implementation of the CKD-EPI 2021 and KFRE and highlights the underutilization of ACR in a community population.

Ultradian rhythms of activity in a wild subterranean rodent.

Many animals adapt their activity patterns to the best environmental conditions using daily rhythms. African mole-rats are among the mammals that have become models for studying how these rhythms can be entrained by light or temperature in experimental laboratory studies. However, it is unclear whether they exhibit similar circadian rhythms in their natural lightless, subterranean environment. In this study, we used biologging to investigate the activity rhythms of wild, highveld mole-rats. We show that their activity cycle exhibited an ultradian rhythm with a length between 4 and 8 h. On an individual level, mole-rats displayed about five activity bouts per day, occurring at various times during the day and night. On a population level, activity peaked in the afternoon, coinciding with the peak in ambient temperature. Our research suggests that wild subterranean mammals, which experience reduced environmental variation, are unlikely to show clear circadian rhythmicity in activity patterns. Instead, activity periods are distributed over several bouts throughout the day and night, and activity coincides with the peak in daily temperature. We propose that ultradian rhythms in activity may be more common than previously thought and discuss how physiological processes may generate differences in periodicity between laboratory and wild populations.

Do Sex Ratio Distorting Microbes Inhibit the Evolution of Pesticide Resistance? An Experimental Test.

We are still largely reliant on pesticides for the suppression of arthropod pests which threaten human health and food production, but the recent rise of evolved resistance among important pest species has reduced pesticide efficacy. Despite this, our understanding of strategies that effectively limit the evolution of resistance remains weak. Male-killing sex ratio distorting microbes (SRDMs), such as Wolbachia and Spiroplasma, are common among arthropod species. Previous theoretical work has suggested that they could limit adaptive potential in two ways: first, because by distorting sex ratios they reduce the effective population size, and second, because infected females produce no male offspring which restricts gene flow. Here we present the results of a novel experiment in which we test the extent by which these two mechanisms limit the adaptive response of arthropods to pesticide. Using a fully factorial design, we manipulated the adult sex ratio of laboratory populations of Drosophila melanogaster, both in the presence and absence of SRDMs, and exposed these populations to six generations of pesticide poisoning. This design allows the effects of SRDMs on sex ratio and their effects on gene flow to be estimated separately. After six generations, individuals from populations with even sex ratios displayed a higher resistance to pesticide relative to individuals from female-biased populations. By contrast, we found no effect of the presence of SRDMs in host populations on pesticide resistance independent of sex ratio. In addition, males were more susceptible to pesticide than females-this was true of flies from both naïve and previously exposed populations. These findings provide the first empirical proof of concept that sex ratio distortion arising from SRDMs can limit adaptation to pesticides, but cast doubt on the theoretical effect of male-killers limiting adaptation by disrupting gene flow.

8185 The diagnosis of primary aldosteronism: testing 2 screening approachesin a large reference laboratory population

8185 The diagnosis of primary aldosteronism: testing 2 screening approachesin a large reference laboratory population

Features of reproduction and postembryonic ontogenesis in voles Microtus kermanensis and M. mystacinus of the subgenus Microtus (Rodentia, Arvicolinae)

The voles Microtus kermanensis Roguin, 1988 and M. mystacinus De Filippi, 1865 are representatives of the “mystacinus” group in the subgenus Microtus (2n = 54). A three-year study of reproduction of these species was conducted in the Laboratory of Theriology of the Zoological Institute RAS. The laboratory populations of voles were created from animals caught in Iran. In this study, 38 pairs of M. kermanensis and 18 pairs of M. mystacinus were under observation. For the study of postembryonic ontogenesis, 39 litters (166 pups) of M. kermanensis voles and 14 litters (51 pups) of M. mystacinus were examined. For comparison, 10 litters (47 pups) of M. arvalis Pallas, 1978 (form “arvalis” from the Vladimir region) were used. The breeding of animals continued all year round. The average number of pups per litter was 4.3 in M. kermanensis, 3.6 in M. mystacinus, and 4.7 in M. arvalis; the sex ratio in all species was close to 1:1. High mortality was noted in the larger M. kermanensis (28.3%), with lower rates in M. mystacinus (15.7%) and M. arvalis (17.0%). In general, the development of pups of all three species during the first 12 days of life is fast. Among the distinctive features, the early separation of the auricles in M. mystacinus is of note. The large M. kermanensis is characterized by earlier divergence of the fingers on the fore and hind limbs, which ends by day 10 (in M. mystacinus and M. arvalis by day 12). Also, in M. kermanensis the timing of incisor eruption is extended; the lower incisors begin to erupt on day 3 and appear by day 9 in 100% of the pups (by day 7 in the other two species). The upper incisors begin to erupt from day 4, and 100% of the pups have them by day 10 (in M. mystacinus and M. arvalis, they completely erupt on day 8). In all three species, their eyes start opening at 9 days and open completely by day 12; such uniformity can serve as confirmation of the phylogenetic proximity of these species. All three species are characterized by the avoidance of incest.

Histone H3-K27 and H3-K9 methylation does not predict lifespan in divergent populations of Drosophila melanogaster

A universal theory of aging remains elusive despite decades of research. Traditional gerontological research has focused on genetic alterations as the driving unit of the aging processes. Recent breakthroughs in cellular reprogramming, transgenerational epigenetic inheritance, and molecular aging clocks have motivated theories proposing that the disruption of epigenetic regulation is the proximal cause of aging. The claim that aging is fundamentally an epigenetic process, however, is largely based on studies using clonal cell populations and genetically identical organisms. Consequently, there has been limited experimental evidence demonstrating the correlation between epigenetic differences and longevity differences among genetically diverse populations. To address this gap in literature we leveraged laboratory populations of the model organism Drosophila melanogaster. Using sister populations with evolved differences in longevity after more than 1 500 generations of divergent life history selection, we measured the methylation at the H3K27 and H3K9 sites which have previously been shown to become dysregulated with age. Here we report that there were no differences in the amount of H3K27me3 or H3K9me2 between 3 replicate population pairs of the divergent lines. These results do not support that epigenetic dysregulation is the underlying cause of aging. Future studies investigating additional indicators of epigenetic dysregulation are required to clarify the role of epigenetics in aging.

Understanding why restrictive trial eligibility criteria are inappropriate

BackgroundAn important difference between explanatory and pragmatic clinical trials concerns eligibility criteria. Eligibility criteria are restrictive in explanatory trials, while pragmatic trials are more inclusive or even all-inclusive. MethodsTo better understand the diverging views regarding eligibility criteria, we examine the contrast between theoretical and clinical medicine, and 3 different research contexts: laboratory research, population studies and clinical trials. In each context we review the purpose for selecting study subjects or research material, as well as the type of inductive inference or generalization that is sought by such selection. ResultsIn each context, selection concerns different things and serves different purposes: In the laboratory, selection concerns the homogenous research material that will help isolate a causal signal. In the epidemiological context selection concerns the (random) sampling method, designed to produce a representative sample of the population. In the clinical trial setting, selection concerns patients in need of care. Restrictive eligibility criteria become inappropriate in the care setting because the aim of the trial is not to represent a population nor to isolate a causal signal, but to find out which patients benefit from treatment. ConclusionThe idea of selecting patients comes from methods that belong to theoretical medicine. In the care setting, most clinical trials should be pragmatic and as inclusive as possible.

The bioefficacy of a novel VECTRON™ T500 indoor residual spray formulation in an experimental huts trial against Anopheles gambiae s.l. populations

Background: The emergence of insecticide resistance and its spread through populations of malaria vectors has decreased the number of insecticides available for control. Insecticide resistance has been observed in vector populations across sub-Saharan Africa in malaria endemic areas. Therefore, new compounds with different modes of action are needed that can be used in the management of resistance. The current study assessed the bioefficacy of the new indoor residual spray formulation, VECTRON™ T500 against Klypson 500 WG and water against laboratory reared and wild populations of Anopheles gambiae s.l.. The comparative experimental hut trial was implemented between June 2022 and December 2022 to determine the efficacy of VECTRON™ T500, containing the active ingredient (ai) broflanilide as a 50 % wettable powder (WP). The efficacy of VECTRON™ T500 was compared with a positive control, Klypson 500 WG, a wettable granule (WG) formulation that contains 50 % clothianidin. Cement and mud walls were sprayed with VECTRON™ T500, Klypson 500 WG with water sprayed as a negative control. The two insecticides and negative control were evaluated monthly for six months against laboratory and the field-derived An. gambiae s.l. using the standard WHO cone bioassays. Each wall had two cones on each day of testing. VECTRON™ T500 was sprayed on both surface types at a rate of 100mg ai/m2 whilst Klypson 500 WG was applied at a rate of 300 mg ai/m2. For both wall surface types, the vector from the laboratory-reared and the wild populations exhibited a low knockdown effect to both VECTRON™ T500 and Klypson 500 WG. A total of 3,840 mosquitoes were used of which 2,880 (75 %) were susceptible colony of An. gambiae s.s. and 960 (25 %) were wild An. gambiae s.l.. The VECTRON™ T500 induced a mortality of 97.8 %-98.1 % in the laboratory population and 83.2-95.0 % wild population mosquitoes on cement and mud-walled huts respectively while Klypson 500 WG ranged from 89.6-99.0 % for wild and 99.0-99.3 % for the laboratory population mosquitoes on cement and mud walls respectively. The knockdown due to VECTRON™ T500 was 7.08 % in the sixth month, while for Klypson 500 WG was 16.04-17.50 %. The monthly wall cone bioassay mortality with VECTRON™ T500 remained over 80 % for 6 months post-spraying for both laboratory and wild populations. The findings of this study have shown VECTRON™ T500 to have extended efficacy against malaria vector mosquitoes when applied to cement and mud walls. The evaluated new IRS formulation, VECTRON™ T500, performed equally with the positive control, Klypson 500 WG, regarding its impact on vector mortality.

Long-term effects of widespread pharmaceutical pollution on trade-offs between behavioural, life-history and reproductive traits in fish.

In our rapidly changing world, understanding how species respond to shifting conditions is of paramount importance. Pharmaceutical pollutants are widespread in aquatic ecosystems globally, yet their impacts on animal behaviour, life-history and reproductive allocation remain poorly understood, especially in the context of intraspecific variation in ecologically important traits that facilitate species' adaptive capacities. We test whether a widespread pharmaceutical pollutant, fluoxetine (Prozac), disrupts the trade-off between individual-level (co)variation in behavioural, life-history and reproductive traits of freshwater fish. We exposed the progeny of wild-caught guppies (Poecilia reticulata) to three field-relevant levels of fluoxetine (mean measured concentrations: 0, 31.5 and 316 ng/L) for 5 years, across multiple generations. We used 12 independent laboratory populations and repeatedly quantified activity and risk-taking behaviour of male guppies, capturing both mean behaviours and variation within and between individuals across exposure treatments. We also measured key life-history traits (body condition, coloration and gonopodium size) and assessed post-copulatory sperm traits (sperm vitality, number and velocity) that are known to be under strong sexual selection in polyandrous species. Intraspecific (co)variation of these traits was analysed using a comprehensive, multivariate statistical approach. Fluoxetine had a dose-specific (mean) effect on the life-history and sperm trait of guppies: low pollutant exposure altered male body condition and increased gonopodium size, but reduced sperm velocity. At the individual level, fluoxetine reduced the behavioural plasticity of guppies by eroding their within-individual variation in both activity and risk-taking behaviour. Fluoxetine also altered between-individual correlations in pace-of-life syndrome traits: it triggered the emergence of correlations between behavioural and life-history traits (e.g. activity and body condition) and between life-history and sperm traits (e.g. gonopodium size and sperm vitality), but collapsed other between-individual correlations (e.g. activity and gonopodium size). Our results reveal that chronic exposure to global pollutants can affect phenotypic traits at both population and individual levels, and even alter individual-level correlations among such traits in a dose-specific manner. We discuss the need to integrate individual-level analyses and test behaviour in association with life-history and reproductive traits to fully understand how animals respond to human-induced environmental change.

Wolbachia confers protection against the entomopathogenic fungus Metarhizium pingshaense in African Aedes aegypti.

Symbiotic and pathogenic microorganisms such as bacteria and fungi represent promising alternatives to chemical insecticides to respond to the rapid increase of insecticide resistance and vector-borne disease outbreaks. This study investigated the interaction of two strains of Wolbachia, wAlbB and wAu, with the natural entomopathogenic fungi from Burkina Faso Metarhizium pingshaense, known to be lethal against Anopheles mosquitoes. In addition to showing the potential of Metarhizium against African Aedes aegypti wild-type populations, our study shows that the wAlbB and wAu provide a protective advantage against entomopathogenic fungal infections. Compared to controls, fungal-infected wAu and wAlbB-carrying mosquitoes showed higher longevity, without any significant impact on fecundity and fertility phenotypes. This study provides new insights into the complex multipartite interaction among the mosquito host, the Wolbachia endosymbiont and the entomopathogenic fungus that might be employed to control mosquito populations. Future research should investigate the fitness costs of Wolbachia, as well as its spread and prevalence within mosquito populations. Additionally, evaluating the impact of Wolbachia on interventions involving Metarhizium pingshaense through laboratory and semi-field population studies will provide valuable insights into the effectiveness of this combined approach.

The cultivable gut bacteria Enterococcus mundtii promotes early-instar larval growth of Conogethes punctiferalis via enhancing digestive enzyme activity.

Gut bacteria are crucial in influencing insect development and even phenotypic plasticity. The yellow peach moth Conogethes punctiferalis, as a significant borer pest, has been the subject of limited reports regarding the structural and diversification changes in its gut microbiota during feeding, and their potential impacts on the growth and development of the host insects. This study, employing 16S rRNA sequencing, demonstrates distinct shifts in the larvae gut microbiome of C. punctiferalis between different feeding stages, highlighting a pronounced diversity in the early-instar with Enterococcus as a predominant genus in laboratory populations. Through in vitro cultivation and sequencing, three bacterial strains - Micrococcus sp., Brevibacterium sp. and Enterococcus mundtii - were isolated and characterized. Bioassays revealed that E. mundtii-infused corn significantly boosts early-instar larval growth, enhancing both body length and weight. Quantitative PCR and spectrophotometry confirmed a higher abundance of E. mundtii in younger larvae, correlating with increased digestive enzyme activity and total protein levels. This study reveals the heightened gut microbiota diversity in early instars of C. punctiferalis larvae, highlighting that Enterococcus represent a predominant bacteria in laboratory populations. In vitro cultivation and bioassays unequivocally demonstrate the significant role of the cultivable gut bacteria E. mundtii in promoting the growth of early-instar larva. These findings provide a solid theoretical foundation for advancing the comprehension of the intricate interactions between gut microbiota and insect hosts, as well as for the development of eco-friendly pest control technologies based on targeted manipulation of insect gut microbial communities. © 2024 Society of Chemical Industry.

Selection of Aphis craccivora (Hemiptera: Aphididae) for Resistance to Thiamethoxam Insecticide under Laboratory Conditions1

Abstract The cowpea aphid, Aphis craccivora Koch (Hemiptera: Aphididae), is a polyphagous pest that causes yield losses in a variety of crops worldwide. Its management relies mainly on the use of chemical insecticides. This study followed the development of resistance to thiamethoxam in A. craccivora under laboratory conditions for 24 generations. The initial median lethal concentration (LC50) of thiamethoxam in a susceptible laboratory population of A. craccivora was 2.62 ppm. Exposure of surviving aphids in each generation to thiamethoxam caused an increase in the LC50 with each successive generation. After 24 generations, the LC50 had increased to 225.83 ppm, an 86.2-fold increase over the initial LC50. Resistance, as indicated by the increasing LC50, appeared as early as the second generation with a 1.4-fold increase over the initial generation. By the 14th generation, the LC50 had increased by 29-fold, and by the 16th generation, it had quickly increased by 69.4-fold. Our results indicate that A. craccivora populations repeatedly exposed to thiamethoxam in a cropping system can lead to rapid development of resistance to the insecticide. Any overuse or other misuse of the pesticide may lead to an even more rapid development of high levels of resistance to thiamethoxam within a short period of time. Elevated levels of the detoxifying enzymes, carboxylesterase, glutathione-S-transferase, and mixed function oxidases, in aphids exhibiting resistance as compared with the initial susceptible population indicated that the detoxifying enzymes, especially the carboxylesterases, are likely involved in facilitating the development of resistance to thiamethoxam in A. craccivora.

Unveiling population-specific outcomes: Examining life cycle traits of different strains of Chironomus riparius exposed to microplastics and cadmium questions generality of ecotoxicological results.

Ecotoxicological tests used for risk assessment of toxicants and its mixtures rely both on classical life-cycle endpoints and bioindicator organisms usually derived from long-term laboratory cultures. While these cultures are thought to be comparable among laboratories and more sensitive than field organisms, it is not well investigated whether this assumption is met. Therefore, we aimed to investigate differential life-cycle endpoints response of two different strains of C. riparius, one originally from Spain and the other from Germany, kept under the same laboratory conditions for more than five years. To highlight any possible differences, the two populations were challenged with exposure to cadmium (Cd), polyvinyl chloride (PVC) microplastics and a co-exposure with both. Our results showed that significant differences between the strains became evident with the co-exposure of Cd and PVC MPs. The German strain showed attenuation of the deleterious Cd effects with microplastic co-exposure in survival and developmental time. Contrary to that, the Spanish strain showed no interaction between the substances. In conclusion, the toxicity-effects of contaminants may vary strongly among laboratory populations, which makes a universal risk assessment evaluation challenging.

Age-related physiological dysregulation progresses slowly in semi-free-ranging chimpanzees.

Lifestyle has widespread effects on human health and aging. Prior results from chimpanzees (Pan troglodytes), one of humans' closest evolutionary relatives, indicate that these lifestyle effects may also be shared with other species, as semi-free-ranging chimpanzees fed a naturalistic diet show healthier values in several specific health biomarkers, compared with their sedentary, captive counterparts. Here, we examined how lifestyle factors associated with different environments affect rates of physiological aging in closely related chimpanzees. We compared physiological dysregulation, an index of biological aging, in semi-free-ranging chimpanzees in an African sanctuary versus captive chimpanzees in US laboratories. If the rate of aging is accelerated by high-calorie diet and sedentism, we predicted greater age-related dysregulation in the laboratory populations. Conversely, if costs of a wild lifestyle accelerate aging, then semi-free-ranging chimpanzees at the sanctuary, whose environment better approximates the wild, should show greater age-related dysregulation. We further tested whether dysregulation differed based on sex or body system, as in humans. We found that semi-free-ranging chimpanzees showed lower overall dysregulation, as well as lower age-related change in dysregulation, than laboratory chimpanzees. Males experienced lower dysregulation than females in both contexts, and the two populations exhibited distinct aging patterns based on body system. Our results support the conclusion that naturalistic living conditions result in healthier aging in chimpanzees. These data provide support for the proposal that lifestyle effects on human health and aging are conserved from deeper into our evolutionary history.

A Path Integral Approach for Allele Frequency Dynamics Under Polygenic Selection.

Many phenotypic traits have a polygenic genetic basis, making it challenging to learn their genetic architectures and predict individual phenotypes. One promising avenue to resolve the genetic basis of complex traits is through evolve-and-resequence experiments, in which laboratory populations are exposed to some selective pressure and trait-contributing loci are identified by extreme frequency changes over the course of the experiment. However, small laboratory populations will experience substantial random genetic drift, and it is difficult to determine whether selection played a roll in a given allele frequency change. Predicting how much allele frequencies change under drift and selection had remained an open problem well into the 21st century, even those contributing to simple, monogenic traits. Recently, there have been efforts to apply the path integral, a method borrowed from physics, to solve this problem. So far, this approach has been limited to genic selection, and is therefore inadequate to capture the complexity of quantitative, highly polygenic traits that are commonly studied. Here we extend one of these path integral methods, the perturbation approximation, to selection scenarios that are of interest to quantitative genetics. In particular, we derive analytic expressions for the transition probability (i.e., the probability that an allele will change in frequency from , to in time ) of an allele contributing to a trait subject to stabilizing selection, as well as that of an allele contributing to a trait rapidly adapting to a new phenotypic optimum. We use these expressions to characterize the use of allele frequency change to test for selection, as well as explore optimal design choices for evolve-and-resequence experiments to uncover the genetic architecture of polygenic traits under selection.

Copy number variation and population-specific immune genes in the model vertebrate zebrafish.

Copy number variation in large gene families is well characterized for plant resistance genes, but similar studies are rare in animals. The zebrafish (Danio rerio) has hundreds of NLR immune genes, making this species ideal for studying this phenomenon. By sequencing 93 zebrafish from multiple wild and laboratory populations, we identified a total of 1513 NLRs, many more than the previously known 400. Approximately half of those are present in all wild populations, but only 4% were found in 80% or more of the individual fish. Wild fish have up to two times as many NLRs per individual and up to four times as many NLRs per population than laboratory strains. In contrast to the massive variability of gene copies, nucleotide diversity in zebrafish NLR genes is very low: around half of the copies are monomorphic and the remaining ones have very few polymorphisms, likely a signature of purifying selection.

Rearing and Experimental Uses of Daphnia: Controlling Animal Nutrition and Assessing Lifespan and Life-History Traits.

Caloric restriction has been found to extend the lifespan of many organisms including mammals and other vertebrates. With lifespans exceeding months to years, age-related experiments involving fish and mammals can be overtly costly, both in terms of time and funding. The freshwater crustacean, Daphnia, has a relatively short lifespan (∼50 to 100 days), which makes it a cost-effective alternative animal model for longevity and aging studies. Besides age-specific mortality, there are a suite of physiological responses connected to "healthspan" that can be tracked as these animals age including growth, reproduction, and metabolic rates. These responses can be complemented by assessment of molecular and cellular processes connected to aging and health. Lifespan and metabolism of this model organism is responsive to long studied modulators of aging, such as rearing temperature and nutritional manipulation, but also pharmacological agents that target aging, e.g., rapamycin, which adds to its usefulness as a model organism. Here we describe how to culture Daphnia for aging experiments including maintaining laboratory populations of Daphnia mothers, growing algal food, and manipulating nutrition of these animals. In addition, we provide methods for tracking common physiological and longevity responses of Daphnia. This protocol provides researchers planning to use this model organism with methods to establish and maintain Daphnia populations and to standardize their experimental approaches. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Culturing algae for Daphnia food Basic Protocol 2: General methods for culturing Daphnia Basic Protocol 3: Standardizing and controlling nutrition for experimental Daphnia Basic Protocol 4: Monitoring Daphnia lifespan Basic Protocol 5: Evaluating Daphnia health: Heart rate and respiration, body mass and growth rates, and reproduction.

Identification and Characterization of Three Novel Solemo-like Viruses in the White-Backed Planthopper, Sogatella furcifera.

Agricultural insects play a crucial role in transmitting plant viruses and host a considerable number of insect-specific viruses (ISVs). Among these insects, the white-backed planthoppers (WBPH; Sogatella furcifera, Hemiptera: Delphacidae) are noteworthy rice pests and are responsible for disseminating the southern rice black-streaked dwarf virus (SRBSDV), a significant rice virus. In this study, we analyzed WBPH transcriptome data from public sources and identified three novel viruses. These newly discovered viruses belong to the plant-associated viral family Solemoviridae and were tentatively named Sogatella furcifera solemo-like virus 1-3 (SFSolV1-3). Among them, SFSolV1 exhibited a prevalent existence in different laboratory populations, and its complete genome sequence was obtained using rapid amplification of cDNA ends (RACE) approaches. To investigate the antiviral RNA interference (RNAi) response in WBPH, we conducted an analysis of virus-derived small interfering RNAs (vsiRNAs). The vsiRNAs of SFSolV1 and -2 exhibited typical patterns associated with the host's siRNA-mediated antiviral immunity, with a preference for 21- and 22-nt vsiRNAs derived equally from both the sense and antisense genomic strands. Furthermore, we examined SFSolV1 infection and distribution in WBPH, revealing a significantly higher viral load of SFSolV1 in nymphs' hemolymph compared to other tissues. Additionally, in adult insects, SFSolV1 exhibited higher abundance in male adults than in female adults.