Convergent molecular evolution of phosphoenolpyruvate carboxylase gene family in C4 and crassulacean acid metabolism plants
Phosphoenolpyruvate carboxylase (PEPC), as the key enzyme in initial carbon fixation of C4and crassulacean acid mechanism (CAM) pathways, was thought to undergo convergent adaptive changes resulting in the convergent evolution of C4 and CAM photosynthesis in vascular plants. However, the integral evolutionary history and convergence of PEPC in plants remain poorly understood. In the present study, we identified the members of PEPC gene family across green plants with seventeen genomic datasets, found ten conserved motifs and modeled three-dimensional protein structures of 90 plant-type PEPC genes. After reconstructing PEPC gene family tree and reconciled with species tree, we found PEPC genes underwent 71 gene duplication events and 16 gene loss events, which might result from whole-genome duplication events in plants. Based on the phylogenetic tree of the PEPC gene family, we detected four convergent evolution sites of PEPC in C4 species but none in CAM species. The PEPC gene family was ubiquitous and highly conservative in green plants. After originating from gene duplication of ancestral C3-PEPC, C4-PEPC isoforms underwent convergent molecular substitution that might facilitate the convergent evolution of C4 photosynthesis in Angiosperms. However, there was no evidence for convergent molecular evolution of PEPC genes between CAM plants. Our findings help to understand the origin and convergent evolution of C4 and CAM plants and shed light on the adaptation of plants in dry, hot environments.
Shu et al. (2022) Convergent molecular evolution of phosphoenolpyruvate carboxylase gene family in C4 and crassulacean acid metabolism plants. PeerJ 10:e12828 https://doi.org/10.7717/peerj.12828
Fast, low-memory detection and localization of large, polymorphic inversions from SNPs
Background Large (>1 Mb), polymorphic inversions have substantial impacts on population structure and maintenance of genotypes. These large inversions can be detected from single nucleotide polymorphism (SNP) data using unsupervised learning techniques like PCA. Construction and analysis of a feature matrix from millions of SNPs requires large amount of memory and limits the sizes of data sets that can be analyzed. Methods We propose using feature hashing construct a feature matrix from a VCF file of SNPs for reducing memory usage. The matrix is constructed in a streaming fashion such that the entire VCF file is never loaded into memory at one time. Results When evaluated on Anopheles mosquito and Drosophila fly data sets, our approach reduced memory usage by 97% with minimal reductions in accuracy for inversion detection and localization tasks. Conclusion With these changes, inversions in larger data sets can be analyzed easily and efficiently on common laptop and desktop computers. Our method is publicly available through our open-source inversion analysis software, Asaph.
Nowling et al. (2022) Fast, low-memory detection and localization of large, polymorphic inversions from SNPs. PeerJ 10:e12831 https://doi.org/10.7717/peerj.12831
Exploring the relationship between ADHD, its common comorbidities, and their relationship to organizational skills
Background Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder affecting numerous executive functioning skills, such as organizational skills. While the relationship between the inattention aspect of ADHD and poor organizational skills is well documented, it is still unclear if lower organizational skills are only associated with ADHD or if they are also associated with other comorbid disorders commonly diagnosed in conjunction with ADHD. The purpose of the present study is to investigate the relationship between organizational skills and ADHD in adults, as well as the impact of comorbid disorders on ADHD in relation to organizational skills. Methods Four hundred seven (n = 201 with a diagnosis of ADHD) adults from the general population were recruited online. Participants completed a measure of organizational skills, measures assessing levels of ADHD, depression, and anxiety, and extensive demographic information related to their diagnosis of ADHD or other possible diagnosis. Results Participants with a diagnosis of ADHD were significantly more likely to have a comorbid diagnosis of depression and/or anxiety. Organizational skills were significantly lower in individuals who reported having received a diagnosis of ADHD, but not in those with a past diagnosis of depression and anxiety. However, organizational skills were lower in individuals currently experiencing higher levels of depression and anxiety. The results of regression analyses suggest that levels of organizational skills are most strongly predicted by inattention and more weakly predicted by comorbid disorders. Discussion These results highlight the centrality of organizational skills deficit in ADHD as well as the influence of the inattention component over other components commonly observed in ADHD on organizational skills. Suggestions for treatment of ADHD in adults are discussed.
Durand et al. (2022) Exploring the relationship between ADHD, its common comorbidities, and their relationship to organizational skills. PeerJ 10:e12836 https://doi.org/10.7717/peerj.12836
Effect of fire on the palatability of plants in an African woodland savanna: varying impacts depending on plant functional groups
Fire and herbivores are two important drivers of changes in vegetation composition, quality and dynamics and both are highly related to each other. Herbivores are known to respond to fire both in terms of foraging decisions and distribution. However, little is known about the actual changes in plant chemistry following a fire event and how long these changes will last. We investigated the effect of fire on two different plant functional groups (grasses and woody species) in a woodland savanna of southern Africa. We studied chemical compounds known to be important for palatability of five perennial grass and seven woody species (trees and shrubs) common in the woodland savanna and known to be utilized by herbivores. We wanted to know if plant chemistry differs between a recently burned site (burned 2 years ago) and a control site, burned 16 years ago, and if grasses and woody species show similar relative differences between sites (i.e., the plants’ response to fire). We found a clear difference in chemical composition patterns between the plant functional groups, with an almost homogenous response to fire among woody species, but higher variability in response among grass species. Furthermore, we found that woody species maintained a higher nutritional value even 2 years after burning, whereas grasses did not show clear differences among the two investigated sites. Hence, few years after burning, woody plants might still serve as an attraction for herbivores, especially browsers, in contrast to grasses. The knowledge about these differences between the two functional groups in response to fire is beneficial for the development of management strategies for large herbivores whether domestic or wild.
Stolter et al. (2022) Effect of fire on the palatability of plants in an African woodland savanna: varying impacts depending on plant functional groups. PeerJ 10:e12721 https://doi.org/10.7717/peerj.12721
Effective asexual reproduction of a widespread soft coral: comparative assessment of four different fragmentation methods
Background Many coral reefs worldwide are experiencing declines in hard corals, resulting in other benthic organisms, e.g., soft corals, becoming more dominant. As such, more studies on the ecophysiology of soft corals are needed. Despite many methods for asexual reproduction of hard corals, effective methods for soft corals, i.e., without a hard skeleton, are scarce. This study, thus, assessed four fragmentation methods, the glue, rubber band, tunnel mesh, and plug mesh method for the pulsating soft coral Xenia umbellata that is widely distributed in the tropical Indo-Pacific. Methods Methods were comparatively assessed by determining the required time and labor for the fragmentation plus the health status of the fragmented corals by measuring their oxygen fluxes and pulsation rates, i.e., a special feature of this soft coral that can be used as a proxy for its health. Results There were no significant health status differences between methods. This was indicated by similar gross photosynthesis (between 7.4 to 9.7 μg O2 polyp−1 h−1) and pulsating rates (between 35 and 44 pulses min−1) among methods. In terms of time/labor intensity and success rates, i.e., the percentage of fragments attached to the desired surface, the plug mesh method was the most efficient method with a significantly higher success rate (95 ± 5%), while the others had a success rate between 5 ± 5 and 45 ± 15%. The time needed for fragmentation, though not significant, was also the shortest (78 ± 11 s fragment−1), while other methods required between 84 ± 14 and 126 ± 8 s frag−1. The plug mesh method may thus be a valuable tool related to the reproduction of soft corals for use in subsequent experimental work.
Kim et al. (2022) Effective asexual reproduction of a widespread soft coral: comparative assessment of four different fragmentation methods. PeerJ 10:e12589 https://doi.org/10.7717/peerj.12589
A novel nutritional index as a predictor of mortality in dilated cardiomyopathy: a retrospective study
Background Research has associated nutritional status with the prognosis of cardiovascular diseases. This study aimed to investigate the prognostic value of a novel nutritional index, triglycerides × total cholesterol × body weight index (TCBI), in patients with dilated cardiomyopathy (DCM). Methods This retrospective cohort study enrolled 445 patients with DCM. The median follow-up period was 2.8 years, and the primary endpoint was all-cause death. Results During follow-up, the all-cause mortality was observed in 135 out of 445 patients (30.3%). In Kaplan–Meier survival analysis, the third TCBI tertile had a lower mortality risk (T3 vs. T2 vs. T1: 16.9% vs. 35.1% vs. 38.9%; log-rank P < 0.001). In the multivariable Cox regression analysis, patients in the third tertile were associated with a decreased mortality, whereas there was no significant difference between the T2 and T1 groups. Moreover, TCBI could significantly improve risk stratification (continuous net reclassification improvement and integrated discrimination improvement) over the Geriatric Nutritional Risk Index (GNRI) and N-terminal pro-brain natriuretic peptide (NT-proBNP). Conclusions TCBI is independently associated with long-term survival in patients with DCM. Combination of TCBI and other biomarkers, such as GNRI and NT-proBNP, can significantly improve prognostic prediction. Further studies with larger sample size are required to validate our results.
Wang et al. (2022) A novel nutritional index as a predictor of mortality in dilated cardiomyopathy: a retrospective study. PeerJ 10:e12704 https://doi.org/10.7717/peerj.12704
Plasma FGF21 concentrations are regulated by glucose independently of insulin and GLP-1 in lean, healthy humans
Background Fibroblast growth factor 21 (FGF21) treatment improves metabolic homeostasis in diverse species, including humans. Physiologically, plasma FGF21 levels increase modestly after glucose ingestion, but it is unclear whether this is mediated by glucose itself or due to a secondary effect of postprandial endocrine responses. A refined understanding of the mechanisms that control FGF21 release in humans may accelerate the development of small-molecule FGF21 secretagogues to treat metabolic disease. This study aimed to determine whether FGF21 secretion is stimulated by elevations in plasma glucose, insulin, or glucagon-like peptide-1 (GLP-1) in humans. Methods Three groups of ten healthy participants were included in a parallel-group observational study. Group A underwent a hyperglycemic infusion; Group B underwent a 40 mU/m2/min hyperinsulinemic euglycemic clamp; Group C underwent two pancreatic clamps (to suppress endogenous insulin secretion) with euglycemic and hyperglycemic stages with an infusion of either saline or 0.5 pmol/kg/min GLP-1. Plasma FGF21 concentrations were measured at baseline and during each clamp stage by ELISA. Results Plasma FGF21 was unaltered during hyperglycemic infusion and hyperinsulinemic euglycemic clamps, compared to baseline. FGF21 was, however, increased by hyperglycemia under pancreatic clamp conditions (P < 0.05), while GLP-1 infusion under pancreatic clamp conditions did not change circulating FGF21 levels. Conclusion Increases in plasma FGF21 are likely driven directly by changes in plasma glucose independent of changes in insulin or GLP-1 secretion. Ecologically valid postprandial investigations are now needed to confirm our observations from basic science infusion models.
Solomon et al. (2022) Plasma FGF21 concentrations are regulated by glucose independently of insulin and GLP-1 in lean, healthy humans. PeerJ 10:e12755 https://doi.org/10.7717/peerj.12755
DnoisE: distance denoising by entropy. An open-source parallelizable alternative for denoising sequence datasets
DNA metabarcoding is broadly used in biodiversity studies encompassing a wide range of organisms. Erroneous amplicons, generated during amplification and sequencing procedures, constitute one of the major sources of concern for the interpretation of metabarcoding results. Several denoising programs have been implemented to detect and eliminate these errors. However, almost all denoising software currently available has been designed to process non-coding ribosomal sequences, most notably prokaryotic 16S rDNA. The growing number of metabarcoding studies using coding markers such as COI or RuBisCO demands a re-assessment and calibration of denoising algorithms. Here we present DnoisE, the first denoising program designed to detect erroneous reads and merge them with the correct ones using information from the natural variability (entropy) associated to each codon position in coding barcodes. We have developed an open-source software using a modified version of the UNOISE algorithm. DnoisE implements different merging procedures as options, and can incorporate codon entropy information either retrieved from the data or supplied by the user. In addition, the algorithm of DnoisE is parallelizable, greatly reducing runtimes on computer clusters. Our program also allows different input file formats, so it can be readily incorporated into existing metabarcoding pipelines.
Antich et al. (2022) DnoisE: distance denoising by entropy. An open-source parallelizable alternative for denoising sequence datasets. PeerJ 10:e12758 https://doi.org/10.7717/peerj.12758
Optimized nitrogen rate, plant density, and irrigation level reduced ammonia emission and nitrate leaching on maize farmland in the oasis area of China
Nitrogen fertilizers play a key role in crop production to meet global food demand. Inappropriate application of nitrogen fertilizer coupled with poor irrigation and other crop management practices threaten agriculture and environmental sustainability. Over application of nitrogen fertilizer increases nitrogen gas emission and nitrate leaching. A field experiment was conducted in China’s oasis irrigation area in 2018 and 2019 to determine which nitrogen rate, plant density, and irrigation level in sole maize (Zea mays L.) cropping system reduce ammonia emission and nitrate leaching. Three nitrogen rates of urea (46-0-0 of N-P2O5-K2O), at (N0 = 0 kg N ha−1, N1 = 270 kg N ha−1, and N2 = 360 kg N ha−1) were combined with three plant densities (D1 = 75,000 plants/ha−1, D2 = 97,500 plants/ha−1, and D3 = 120,000 plants/ha−1) with two irrigation levels (W1 = 5,250 m3/hm2 and W2 = 4,740 m3/hm2) using a randomized complete block design. The results showed that, both the main and interaction effects of nitrogen rate, plant density, and irrigation level reduced nitrate leaching (p < 0.05). In addition, irrigation level × nitrogen rate significantly (p < 0.05) reduced ammonia emission. Nitrate leaching and ammonia emission decreased with higher irrigation level and higher plant density. However, high nitrogen rates increased both nitrate leaching and ammonia emission. The study found lowest leaching (0.35 mg kg−1) occurring at the interaction of 270 kg N ha−1 × 120,000 plants/ha−1 × 4,740 m3/hm2, and higher plant density of 120,000 plants/ha−1 combined with 0 kg N ha−1 and irrigation level of 5,250 m3/hm2 recorded the lowest ammonia emission (0.001 kg N)−1. Overall, ammonia emission increased as days after planting increased while nitrate leaching decreased in deeper soil depths. These findings show that, though the contributory roles of days after planting, soil depth, amount of nitrogen fertilizer applied and year of cultivation cannot be undermined, it is possible to reduce nitrate leaching and ammonia emission through optimized nitrogen rate, plant density and regulated irrigation for agricultural and environmental sustainability.
Asibi et al. (2022) Optimized nitrogen rate, plant density, and irrigation level reduced ammonia emission and nitrate leaching on maize farmland in the oasis area of China. PeerJ 10:e12762 https://doi.org/10.7717/peerj.12762
Reconstructing the transmission dynamics of varicella in Japan: an elevation of age at infection
Background In Japan, routine two-dose immunization against varicella has been conducted among children at ages of 12 and 36 months since 2014, and the vaccination coverage has reached around 90%. To understand the impact of routine varicella vaccination, we reconstructed the epidemiological dynamics of varicella in Japan. Methods Epidemiological and demographic datasets over the past three decades were analyzed to reconstruct the number of susceptible individuals by age and year. To estimate the annual risk of varicella infection, we fitted a balance equation model to the annual number of cases from 1990 to 2019. Using parameter estimates, we reconstructed varicella dynamics starting from 1990 and modeled future dynamics until 2033. Results Overall varicella incidence declined over time and the annual risk of infection among children younger than 10 years old decreased monotonically starting in 2014. Conversely, varicella incidence among teenagers (age 10 to 14 years) has increased each year since 2014. A substantial number of unvaccinated individuals born before the routine immunization era remained susceptible and aged without contracting varicella, while the annual risk of infection among teenagers aged 10 to 14 years increased starting in 2011 despite gradual expansion of varicella vaccine coverage. The number of susceptible individuals decreased over time in all age groups. Modeling indicated that susceptibility rates among pre-school children aged 1 to 4 years will remain low. Conclusion Routine varicella vaccination has successfully reduced infections in pre-school and early primary school age children, but has also resulted in increased infection rates among adolescents. This temporary increase was caused both by the increased age of susceptible individuals and increased transmission risk among adolescents resulting from the dynamic nature of varicella transmission. Monitoring susceptibility among adolescents will be important to prevent outbreaks over the next decade.
Suzuki et al. (2022) Reconstructing the transmission dynamics of varicella in Japan: an elevation of age at infection. PeerJ 10:e12767 https://doi.org/10.7717/peerj.12767