Population Fitness Research Articles

DNAR-14. MODULATING POPULATIONAL VARIANCE OF METHYL-GUANINE METHYL TRANSFERASE (MGMT) EXPRESSION THROUGH MICRORNA DEGRADATION: A NOVEL MECHANISM OF TEMOZOLOMIDE RESISTANCE

Abstract O6 methyl-guanine methyltransferase (MGMT) restores alkylated DNA to its undamaged form in a stochiometric manner to prevent the cytotoxic effects of temozolomide (TMZ), a DNA alkylating agent used as a standard-of-care treatment for glioblastomas. We previously demonstrated that he microRNA, miR-181d, post-transcriptionally repressed MGMT expression. Here, we show that treatment of glioblastoma cells with TMZ induced a feed-forward cascade resulting in an ataxia telangiectasia and Rad3 (ATR) and polyribonucleotide nucleotidyl transferase 1 (PNPT1)-dependent degradation of miR-181d. Single-cell analyses revealed such miR-181d degradation induced an: 1) increased mean level of MGMT expression and 2) widened the variance in MGMT expression in the cell population. While the former is known to confer increased population fitness to temozolomide, the importance of the latter is unknown. By mixing cultures derived from isogenic glioblastoma subclones with distinct MGMT expression levels, we generated glioblastoma cell populations with comparable mean MGMT expression levels while differing in the populational variance in MGMT expression (classified as “wide” or “narrow”). Despite comparable mean levels of MGMT expression, the glioblastoma population with wide variance exhibited increased temozolomide resistance relative to the population with the narrow variance, in vitro and in vivo. Transfection of miR-181d into the wide-variance population narrows the variance of MGMT expression and restores TMZ sensitivity to levels comparable to that observed in miR-181d transfected narrow-variance populations. These findings suggest that TMZ-induced miR-181d degradation enhanced TMZ resistance through modulation of both the mean and variance of MGMT expression, mechanisms which may be extrapolated to microRNA biology in general.

Phenotypic homogenization and potential fitness constraints following non-native introgression in an endemic sportfish.

Introgressive hybridization may lead to contrasting evolutionary outcomes that are difficult to predict, since they depend on the fitness effects of endogenous genomic interactions and environmental factors. Conservation of endemic biodiversity may be more effective with require direct measurement of introgressed ancestry and fitness in wild populations, especially for keystone taxa at risk of hybridization following species introductions. We assessed the relationship of non-native ancestry with growth and body condition in the basin-restricted Neosho Bass (Micropterus velox; NB), focusing on two streams in the NB native range that are admixed extensively with non-native Smallmouth Bass (M. dolomieu; SMB). We quantified genetic composition of 116 fish from Big Sugar Creek (N=46) and Elk River (N=70) at 14 microsatellite loci. Using back-calculated total length-at-age estimated from sagittal otoliths, we assessed whether genetic ancestry explained variation in von Bertalanffy growth model parameters, accounting for sex and stream effects. We then assessed the relationship of ancestry and body condition. We found no differences in growth parameters by sex, stream, or ancestry, suggesting phenotypic homogenization which could be mediated by selection on body size. We found a negative correlation between SMB ancestry and condition, including lower condition in Big Sugar Creek, possibly reflecting a trade-off between maximum length and condition with respect to overall fitness. We show that ongoing non-native introgression, which may be augmented by anthropogenic SMB introductions, may attenuate evolutionary differentiation between species and directly influence fitness, possibly having critical implications for long-term persistence and management of adaptive potential in a popular and ecologically important endemic sportfish.

Fisheries-induced life-history changes recover in experimentally harvested fish populations.

Overfishing is one of the greatest threats to fish populations. Size-selective harvesting favours faster juvenile growth, younger maturation, small adult body size and low reproductive output. Such changes might be slow to recover and ultimately threaten population fitness and survival. To study the recovery potential of exploited experimental populations, we compared life-history traits in three differently size-selected experimental lines (large-selected, small-selected and random-selected) after five generations of harvesting and 10 subsequent generations of recovery (i.e. cessation of harvesting). We show that after a recovery period twice as long as the harvesting period, the differences in adult body size among the selection lines have eroded. While there was still a significant body size difference among the selection lines, this did not translate to differences in reproductive success. Although size-selective harvesting causes phenotypic changes in exploited fish populations, we show that such changes are reversible if the recovery period is long enough.

Research on solving multi-preference intelligent scheduling problem based on improved genetic algorithm

Abstract. The paper will use the improved genetic algorithm that adds Gaussian perturbation based on the standard deviation of the population fitness and increases the variance probability operation to optimize the traditional genetic algorithm, and after iterating until the optimal scheduling strategy is found, we combine this algorithm with a mathematical model, and adopt a variety of variations to improve the efficiency of the algorithm. Among them, we take into account the customer flow, area of the store, employee work preference and other related factors to maximize its adaptability. We use real store employee data for simulation example experimental evidence, and compared with other algorithms, the results show that the study of the scheduling optimization ideas and algorithms are practical and feasible.

Effect of Chlorantraniliprole on Life History Traits and Relative Fitness of Laboratory-Selected Resistant and Susceptible Populations of Spodoptera litura (Lepidoptera: Noctuidae).

Insecticides are widely used to control pests and improve agricultural yield. The use of indiscriminate amounts and persistent pesticides has not only resulted in insect pest resistance challenges but has also harmed non-target organisms and contaminated the environment. We assessed the cost-effectiveness of Spodoptera litura (Fabricius) resistance to chlorantraniliprole (CTPR) as part of insect resistance control programs. S. litura larvae were collected from the fields and treated with chlorantraniliprole for 15 generations. Compared to the unselected population (Unsel-Lab), the chlorantraniliprole-selected population (CTPR-Sel) of S. litura exhibited a resistance level of 98.23 times. The findings demonstrated that the chlorantraniliprole-resistant genotype had lower egg-to-adult survivability, longer egg-to-adult developing times, and lower fecundity than the chlorantraniliprole-susceptible genotype. Compared to the Unsel-Lab population, the CTPR-Sel population of S. litura had a poorer relative fitness (0.44) at LC30 and shorter male/female longevity. Demographic parameters, including net reproductive rate (R0) and intrinsic (rm) and finite rate of increase (λ), were lower in the CTPR-Sel strain than in Unsel-Lab S. litura. These findings demonstrate that chlorantraniliprole resistance in S. litura has fitness costs at the individual and population levels, implying that removing the selecting agent from the environment might result in less resistance and opportunities for susceptibility restoration. As a result, the current work could help to determine effective management strategies to prevent chlorantraniliprole resistance in S. litura.

Determining the Fitness Level of People with Down Syndrome Living in Kosovo Based on the ALPHA Protocol

Purpose: This study aimed to establish national norm values for body composition and fitness levels among individuals with Down syndrome. It also aimed to investigate gender differences in body composition features and fitness parameters, analyze the impact of the region where individuals with Down syndrome reside, and compare their fitness levels with international peers. Methods: The sample included 81 participants, 40 females (height: 146.6±4.88 cm, weight: 63.6±16.4 kg) and 41 males (height: 157.4±6.21 cm, weight: 66.8±14.8 kg). To assess the physical fitness levels of the participants with Down syndrome, a modified version of the ALPHA testing protocol was used. Findings: The results demonstrated significant gender differences (p<0.05) in body composition and fitness parameters, with males generally exhibiting better outcomes compared to females. Moreover, significant disparities (p<0.05) in body composition and fitness parameters were observed among individuals with Down syndrome residing in different regions of Kosovo. Noteworthy gender disparities exist in terms of body composition and physical fitness metrics, with male participants achieving superior results compared to their female counterparts. Furthermore, noticeable variations were observed among the regional Down syndrome centers, with participants from older centers displaying improved fitness metrics and body composition features compared to those from newly established facilities. Conclusion: Gender differences in body composition and fitness were evident, with males outperforming females, except in muscle mass. Future studies should explore fitness and health barriers in Kosovo's DS population, with a focus on improving physical activity through tailored strategies.

Temporal trends in weight-based disparities in physical fitness of children: 30-years of continuous surveillance through Slovenian national system

BackgroundObesity in childhood has deleterious consequences for health while improving physical fitness can significantly reduce health risks related to high body mass index. We aimed to examine the evolution of disparities in physical fitness based on weight status among 7–15-year-olds in Slovenia between 1989 and 2019 and compare these trends across sex, age and socioeconomic status.MethodsWe used annual data collected within the SLOfit monitoring system in the period between 1989 and 2019, totalling 4,256,930 participants (about 137 000 per year). We examined cardiorespiratory fitness (600-m run test), muscular fitness (60-s sit-ups, bent arm hang, and standing broad jump test) and skill-related fitness (backwards obstacle course, 60-m dash, arm plate tapping). We grouped children according to the IOTF cut-offs for BMI to those living with normal weight or excess weight and estimated changes in physical fitness over time by fitting quantile regression models separately by sex and age group, and then using segmented regression to identify the patterns of trends over time.ResultsWeight-based disparities in physical fitness were large in 1989 and have further increased by 2019. The increase in disparities was generally around 5 percentiles larger in boys, and 10–15-year-olds compared to younger children. It was particularly pronounced for body core strength and speed in boys (up to 15 and 19 percentiles, respectively) and upper body strength and speed among girls (up to 13 percentiles). Most of the increase in disparities in health-related fitness accumulated during the 2010s, when the fitness of children generally improved, but much less so in children living with excess weight.ConclusionsDespite recent improvements in population fitness levels, children with excess weight seem to be left behind, which adds to existing health inequalities. Our results should encourage policymakers to redesign policies aimed at promoting physical activity and enhancing physical fitness to make them more equitable and ultimately lead to reducing inequalities in fitness.

Effects of continuous and transgenerational rearing in peanut leaves on the performance and enzyme activity of Spodoptera frugiperda (Lepidoptera: Noctuidae).

The invasive fall armyworm (FAW), Spodoptera frugiperda, is a polyphagous pest that significantly threatens crops worldwide. FAW may undergo adaptation, enhancing its ability to infect specific plant hosts. However, there is limited knowledge on this topic. After 8 generations of constant rearing on peanut leaves, the performance and enzyme activities of FAW were investigated in this study. Compared to FAW fed on the peanut cultivars 'Fuhua 8' and 'Quanhonghua 1' for 2 generations, those grown on leaves for 5 to 8 generations had significantly shorter pre-adult development times and total preoviposition periods. Fecundity also increased significantly, resulting in an overall improvement in population fitness as measured by demographic parameters. However, the F2 generation of FAW fed on corn leaves outperformed the F8 generation of FAW fed on peanut leaves. In the F2 generation, the FAW peanut population exhibited 30-55% supernumerary larval molts, which decreased substantially in the F5 and F8 generations. Notably, supernumerary larval molts displayed pupation and emergence rates comparable to normal larvae, regardless of the peanut cultivar or rearing generation. The activities of lipase and acetylcholinesterase increased significantly from the F2 to F8 generations, showing substantial negative and positive correlations with larval development time and fecundity, respectively. In conclusion, FAW demonstrated inferior performance on peanut leaves compared to corn leaves, despite its performance was significantly improved after 5 to 8 generations of acclimation. These results suggest that corn will continue to be the primary target crop for FAW in China.

Determining star formation rates in AGN hosts from strong optical emission lines

Abstract The influence of Active Galactic Nuclei (AGN) on star formation within their host galaxies remains a topic of intense debate. One of the primary challenges in quantifying the star formation rate (SFR) within AGN hosts arises from the prevalent assumption in most methodologies, which attribute gas excitation to young stars alone. However, this assumption does not consider the contribution of the AGN to the ionization of the gas in their environment. To address this issue, we evaluate the use of strong optical emission lines to obtain the SFR surface density (ΣSFRAGN) in regions predominantly ionized by an AGN, using a sample of 293 AGN hosts from the MaNGA survey, with SFR measurements available through stellar population fitting. We propose calibrations involving the Hα and [O iii]λ5007 emission lines, which can be used to determine ΣSFRAGN, resulting in values consistent with those estimated through stellar population fitting.

Galaxy Assembly Bias in the Stellar-to-halo Mass Relation for Red Central Galaxies from SDSS

We report evidence of galaxy assembly bias—the correlation between galaxy properties and biased secondary halo properties at fixed halo mass (M H)—in the stellar-to-halo mass relation for red central galaxies from the Sloan Digital Sky Survey. In the M H = 1011.5–1013.5 h −1 M ⊙ range, central galaxy stellar mass (M *) is correlated with the number density of galaxies within 10 h −1 Mpc (δ 10), a common proxy for halo formation time. This galaxy assembly bias signal is also present when M H, M *, and δ 10 are substituted with group luminosity, galaxy luminosity, and metrics of the large-scale density field. To associate differences in δ 10 with variations in halo formation time, we fitted a model that accounts for (1) errors in the M H measured by the J. L. Tinker group catalog and (2) the level of correlation between halo formation time and M * at fixed M H. Fitting of this model yields that (1) errors in M H are ∼0.15 dex and (2) halo formation time and M * are strongly correlated (Spearman’s rank correlation coefficient ∼0.85). At fixed M H, variations of ∼0.4 dex in M * are associated with ∼1–3 Gyr variations in halo formation time and galaxy formation time (from stellar population fitting). These results are indicative that halo properties other than M H can impact central galaxy assembly.

Collective exploitation of large prey by group foraging shapes aggregation and fitness of cnidarian polyps

Group living is widespread and beneficial to metazoans. It improves protection and survival opportunities, reinforcing interspecific competitiveness. Benthic cnidarians often colonize large surfaces. Evidence of collective capture and exploitation of large prey by small, clumped polyps suggests that aggregation is functional to access food resources hardly achievable by isolated individuals. In turn, the chance to catch large prey may represents a driver of aggregation in polyps, whether beneficial to their fitness. Here, the effects of group foraging on aggregation, asexual reproduction, and growth rates of Aurelia coerulea von Lendenfeld 1884 polyps were experimentally tested by providing them with either small or large prey, or a mix of both to simulate the co-occurrence of preys at sea. As expected, some polyps were not able to reach the large prey. Hence, the population was a posteriori divided into group-foragers and solitary-feeders. In general, the large prey diet resulted in higher population fitness and when simultaneously supplied with the small prey represented an energetic booster resulting beneficial for all group-members. The decrease of interindividual distances was reported among group-foragers, that converged towards each other. Cnidarians are basal in metazoan evolution, and the comprehension of their collective foraging behavior, as well as the processes leading to the selective feature driving them to forage in group or not, may be essential to better understand the evolution and spread of social foraging in animals. Moreover, the access to large prey by sessile polyps of Aurelia coerulea could be pivotal in determining the increase in abundance of adult bloom-forming medusae.

Molecular and structural insights into SARS-CoV-2 evolution: from BA.2 to XBB subvariants.

Due to the incessant emergence of various SARS-CoV-2 variants with enhanced fitness in the human population, controlling the COVID-19 pandemic has been challenging. Understanding how the virus enhances its fitness during a pandemic could offer valuable insights for more effective control of viral epidemics. In this manuscript, we review the evolution of SARS-CoV-2 from early 2022 to the end of 2023-from Omicron BA.2 to XBB descendants. Focusing on viral evolution during this period, we provide concrete examples that SARS-CoV-2 has increased its fitness by enhancing several functions of the spike (S) protein, including its binding affinity to the ACE2 receptor and its ability to evade humoral immunity. Furthermore, we explore how specific mutations modify these functions of the S protein through structural alterations. This review provides evolutionary, molecular, and structural insights into how SARS-CoV-2 has increased its fitness and repeatedly caused epidemic surges during the pandemic.

Genetic rescue often leads to higher fitness as a result of increased heterozygosity across animal taxa.

Biodiversity loss has reached critical levels partly due to anthropogenic habitat loss and degradation. These landscape changes are damaging as they can fragment species distributions into small, isolated populations, resulting in limited gene flow, population declines and reduced adaptive potential. Genetic rescue, the translocation of individuals to increase genetic diversity and ultimately fitness, has produced promising results for fragmented populations but remains underutilized due to a lack of long-term data and monitoring. To promote a better understanding of genetic rescue and its potential risks and benefits over the short-term, we reviewed and analysed published genetic rescue attempts to identify whether genetic diversity increases following translocation, and if this change is associated with increased fitness. Our review identified 19 studies that provided genetic and fitness data from before and after the translocation; the majority of these were on mammals, and included experimental, natural and conservation-motivated translocations. Using a Bayesian meta-analytical approach, we found that on average, genetic diversity and fitness increased in populations post translocations, although there were some exceptions to this trend. Overall, genetic diversity was a positive predictor of population fitness, and in some cases this relationship extended three generations post-rescue. These data suggest a single translocation can have lasting fitness benefits, and support translocation as another tool to facilitate conservation success. Given the limited number of studies with long-term data, we echo the need for genetic monitoring of populations post-translocation to understand whether genetic rescue can also limit the loss of adaptive potential in the long-term.

An estimate of fitness reduction from mutation accumulation in a mammal allows assessment of the consequences of relaxed selection.

Each generation, spontaneous mutations introduce heritable changes that tend to reduce fitness in populations of highly adapted living organisms. This erosion of fitness is countered by natural selection, which keeps deleterious mutations at low frequencies and ultimately removes most of them from the population. The classical way of studying the impact of spontaneous mutations is via mutation accumulation (MA) experiments, where lines of small effective population size are bred for many generations in conditions where natural selection is largely removed. Such experiments in microbes, invertebrates, and plants have generally demonstrated that fitness decays as a result of MA. However, the phenotypic consequences of MA in vertebrates are largely unknown, because no replicated MA experiment has previously been carried out. This gap in our knowledge is relevant for human populations, where societal changes have reduced the strength of natural selection, potentially allowing deleterious mutations to accumulate. Here, we study the impact of spontaneous MA on the mean and genetic variation for quantitative and fitness-related traits in the house mouse using the MA experimental design, with a cryopreserved control to account for environmental influences. We show that variation for morphological and life history traits accumulates at a sufficiently high rate to maintain genetic variation and selection response. Weight and tail length measures decrease significantly between 0.04% and 0.3% per generation with narrow confidence intervals. Fitness proxy measures (litter size and surviving offspring) decrease on average by about 0.2% per generation, but with confidence intervals overlapping zero. When extrapolated to humans, our results imply that the rate of fitness loss should not be of concern in the foreseeable future.

Detection and characterization of detached tidal dwarf galaxies

Tidal interactions between galaxies often give rise to tidal tails, which can harbor concentrations of stars and interstellar gas resembling dwarf galaxies. Some of these tidal dwarf galaxies (TDGs) have the potential to detach from their parent galaxies and become independent entities, but their long-term survival is uncertain. In this study, we conducted a search for detached TDGs associated with a sample of 39 interacting galaxy pairs in the local Universe using infrared, ultraviolet, and optical images. We employed IR colors and UV/optical/IR spectral energy distributions to identify potential interlopers, such as foreground stars or background quasars. Through spectroscopic observations using the Boller and Chivens spectrograph at San Pedro Mártir Observatory, we confirmed that six candidate TDGs are at the same redshift as their putative parent galaxy pairs. We identified and measured emission lines in the optical spectra and calculated nebular oxygen abundances, which range from log(O/H) = 8.10 ± 0.01 to 8.51 ± 0.02. We have serendipitously discovered an additional detached TDG candidate in Arp72 using available spectra from SDSS. Utilizing the photometric data and the CIGALE code for stellar population and dust emission fitting, we derived the stellar masses, stellar population ages, and stellar metallicities for these detached TDGs. Compared to standard mass-metallicity relations for dwarf galaxies, five of the seven candidates have higher than expected metallicities, confirming their tidal origins. One of the seven candidates remains unclear due to large uncertainties in metallicity, and another has stellar and nebular metallicities compatible with those of a preexisting dwarf galaxy. The latter object is relatively compact in the optical relative to its stellar mass, in contrast to the other candidate TDGs, which have large diameters for their stellar masses compared to most dwarf galaxies. The derived stellar population ages range from 100 Myr to 900 Myr, while the inferred stellar masses are between 2 × 106 M⊙ and 8 × 107 M⊙. Four of the six TDGs are associated with the gas-rich M51-like pair Arp 72, one TDG is associated with a second M51-like pair Arp 86, and another is associated with Arp 65, an approximately equal mass pair. In spite of the relatively low stellar masses of these TDGs, they have survived for at least 100–900 Myrs, suggesting that they are stable and in dynamical equilibrium. We conclude that encounters with a relatively low-mass companion (1/10th–1/4th of the mass of the primary) can also produce long-lasting TDGs.

Cluster Heat Selection Optimization in Wsn Via Genetic Based Evolutionary Algorithm and Secure Data Transmission Using Paillier Homomorphic Cryptosystem

Introduction: Wireless Sensor Networks (WSNs) consist of sensor nodes requiring energy-saving measures to extend their lifespan. Traditional solutions often lead to premature node failure due to non-adaptive network setups. Differential Evolution (DE) and Genetic Algorithms (GA) are two key evolutionary algorithms used for optimizing cluster head (CH) selection in WSNs to enhance energy efficiency and prolong network lifetime.Methods: This study compares DE and GA for CH selection optimization, focusing on energy efficiency and network lifespan. It also introduces an improved decryption method for the Paillier homomorphic encryption system to reduce decryption time and computational cost.Results: Experiments show GA outperforms DE in the number of rounds for the first node to die (FND) and achieves a longer network lifespan, despite fewer rounds for the last node to die (LND). GA has slower fitness convergence but higher population fitness values and significantly faster decoding speeds.Conclusion: GA is more effective than DE for CH selection in WSNs, leading to an extended network lifespan and better energy efficiency. Despite slower fitness convergence, GA's higher fitness values and improved decoding speeds make it a superior choice. The enhancements to the Paillier encryption system further increase its efficiency, offering a robust solution for secure and efficient WSN operation

Implications of cypermethrin exposure on population dynamics and fitness traits of laboratory-selected resistant and susceptible populations of Spodoptera litura (Fabricius)

The tobacco cutworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) is an economically important agricultural polyphagous pest worldwide. It has shown high resistance to several insecticides, including cypermethrin, a synthetic pyrethroid that is used in large-scale commercial agricultural applications. The present study investigated the development of selection-induced resistance to cypermethrin and associated fitness costs in S. litura. After continuous exposure to cypermethrin for consecutive fifteen generations, the cypermethrin-selected population (CYP-Sel) of S. litura developed a 21.2-fold resistance. The CYP-Sel strain had a relative fitness of 0.16 when treated with LC50, prolonged larval duration, and development time. Meanwhile, the strain also showed shorter adult duration, lower fecundity, and hatchability compared with the Unsel-Lab population. CYP-Sel population showed a significant disadvantage in intrinsic rate of natural increase (rm), net reproductive rate (Ro), and finite rate of increase (λ) when compared to the Unsel-Lab population. This knowledge could help to design resistance management strategies against this particular pest, along with potential management strategies to overcome the development of resistance.

Eco-toxicity assessment of polypropylene microplastics in juvenile zebrafish (Danio rerio)

In recent years, everyone has recognized microplastics as an emerging contaminant in aquatic ecosystems. Polypropylene is one of the dominant pollutants. The purpose of this study was to examine the effects of exposing zebrafish (Danio rerio) to water with various concentrations of polypropylene microplastics (11.86 ± 44.62 μm), including control (0 mg/L), group 1 (1 mg/L), group 2 (10 mg/L), and group 3 (100 mg/L) for up to 28 days (chronic exposure). The bioaccumulation of microplastics in the tract was noted after 28 days. From the experimental groups, blood and detoxifying organs of the liver and brain were collected. Using liver tissues evaluated the toxic effects by crucial biomarkers such as reactive oxygen species, anti-oxidant parameters, oxidative effects in protein & lipids, total protein content and free amino acid level. The study revealed that the bioaccumulation of microplastics in the organisms is a reflection of the oxidative stress and liver tissue damage experienced by the group exposed to microplastics. Also, apoptosis of blood cells was observed in the treated group as well as increased the neurotransmitter enzyme acetylcholine esterase activity based on exposure concentration-dependent manner. The overall results indicated bioaccumulation of microplastics in the gut, which led to increased ROS levels. This consequently affected antioxidant biomarkers, ultimately causing oxidation of biomolecules and liver tissue injury, as evidenced by histological analysis. This study concludes that chronic ingestion of microplastics causes considerable effects on population fitness in the aquatic environment, as well as other ecological complications, and is also critical to understand the magnitude of these contaminants' influence on ichthyofauna.

An improved differential evolution with adaptive population allocation and mutation selection

In order to improve the performance of differential evolution (DE) for different optimization problems, an improved DE with adaptive population allocation and mutation selection (iDE-APAMS) is proposed. First, different mutation strategies are selected to constitute the exploration strategy pool and the exploitation strategy pool. The exploration strategy pool is mainly used for global search to increase the population diversity; the exploitation strategy pool is primarily used for local search to accelerate the convergence and improve the solution accuracy. Second, different mutation strategies obtain population resources dynamically through cooperation and competition. Mutation strategies in the same strategy pool first compete for population resources with mutation strategies in the other strategy pool through cooperation, and in this way the population is allocated between the two strategy pools. Then within each strategy pool, different mutation strategies compete with each other to obtain corresponding population resources. Third, mutation scale factor and crossover rate are adaptively adjusted based on population diversity and fitness improvement. Finally, the Levy random walk is applied to individuals with better fitness at the later stage of the iteration to avoid falling into local optima and further improve the accuracy of the solution. The iDE-APAMS is compared with 4 classical DE variants and 11 state-of-the-art algorithms on the CEC2013, CEC2014, and CEC2017 benchmark test suites respectively, and it is also tested on 22 real-world optimization problems in CEC2011. The results show that iDE-APAMS can improve the convergence of the algorithm and the stability of the solution, and it is statistically significantly better than the comparison algorithms.

Red-light-dependent chlorophyll synthesis kindles photosynthetic recovery of chlorotic dormant cyanobacteria using a dark-operative enzyme

Chlorosis dormancy resulting from nitrogen starvation and its resuscitation upon available nitrogen contributes greatly to the fitness of cyanobacterial population under nitrogen-fluctuating environments. The reinstallation of the photosynthetic machinery is a key process for resuscitation from a chlorotic dormant state; however, the underlying regulatory mechanism is still elusive. Here, we reported that red light is essential for re-greening chlorotic Synechocystis sp. PCC 6803 (a non-diazotrophic cyanobacterium) after nitrogen supplement under weak light conditions. The expression of dark-operative protochlorophyllide reductase (DPOR) governed by the transcriptional factor RpaB was strikingly induced by red light in chlorotic cells, and its deficient mutant lost the capability of resuscitation from a dormant state, indicating DPOR catalyzing chlorophyll synthesis is a key step in the photosynthetic recovery of dormant cyanobacteria. Although light-dependent protochlorophyllide reductase is widely considered as a master switch in photomorphogenesis, this study unravels the primitive DPOR as a spark to activate the photosynthetic recovery of chlorotic dormant cyanobacteria. These findings provide new insight into the biological significance of DPOR in cyanobacteria and even some plants thriving in extreme environments.