The biology and pathogenicity of Clostridium perfringens type F: a common human enteropathogen with a new(ish) name.

SUMMARYIn the 2018-revised Clostridium perfringens typing classification system, isolates carrying the enterotoxin (cpe) and alpha toxin genes but no other typing toxin genes are now designated as type F. Type F isolates cause food poisoning and nonfoodborne human gastrointestinal (GI) diseases, which most commonly involve type F isolates carrying, respectivefooly, a chromosomal or plasmid-borne cpe gene. Compared to spores of other C. perfringens isolates, spores of type F chromosomal cpe isolates often exhibit greater resistance to food environment stresses, likely facilitating their survival in improperly prepared or stored foods. Multiple factors contribute to this spore resistance phenotype, including the production of a variant small acid-soluble protein-4. The pathogenicity of type F isolates involves sporulation-dependent C. perfringens enterotoxin (CPE) production. C. perfringens sporulation is initiated by orphan histidine kinases and sporulation-associated sigma factors that drive cpe transcription. CPE-induced cytotoxicity starts when CPE binds to claudin receptors to form a small complex (which also includes nonreceptor claudins). Approximately six small complexes oligomerize on the host cell plasma membrane surface to form a prepore. CPE molecules in that prepore apparently extend ß-hairpin loops to form a ß-barrel pore, allowing a Ca2+ influx that activates calpain. With low-dose CPE treatment, caspase-3-dependent apoptosis develops, while high-CPE dose treatment induces necroptosis. Those effects cause histologic damage along with fluid and electrolyte losses from the colon and small intestine. Sialidases likely contribute to type F disease by enhancing CPE action and, for NanI-producing nonfoodborne human GI disease isolates, increasing intestinal growth and colonization.

Complete telomere-to-telomere assemblies of two sorghum genomes to guide biological discovery.

The assembly of two sorghum T2T genomes corrected the assembly errors in the current reference, uncovered centromere variation, boosted functional genomics research, and accelerated sorghum improvement.

Revealing the Synergistic Effect of Cation and Anion Vacancies on Enhanced Fenton-Like Reaction: The Electron Density Modulation of O 2p-Co 3d Bands.

Defect engineering is considered as a flexible and effective mean to improve the performance of Fenton-like reactions. Herein, a simple method is employed to synthesize Co3O4 catalysts with Co-O vacancy pairs (VP) for peroxymonosulfate (PMS) activation. Multi-scaled characterization, experimental, and simulation results jointly revealed that the cation vacancies-VCo contributed to enhanced conductivity and anion vacancies-VO provided a new active center for the 1O2 generation. Co3O4-VP can optimize the O 2p and Co 3d bands with the strong assistance of synergistic double vacancies to reduce the reaction energy barrier of the "PMS → Co(IV) = O → 1O2" pathway, ultimately triggering the stable transition of mechanism. Co3O4-VP catalysts with radical-nonradical collaborative mechanism achieve the synchronous improvement of activity and stability, and have good environmental robustness to favor water decontamination applications. This result highlights the possibility of utilizing anion and cation vacancy engineering strategies to rational design Co3O4-based materials widely used in catalytic reactions.

Multimodal fall detection for solitary individuals based on audio-video decision fusion processing.

Falls often pose significant safety risks to solitary individuals, especially the elderly. Implementing a fast and efficient fall detection system is an effective strategy to address this hidden danger. We propose a multimodal method based on audio and video. On the basis of using non-intrusive equipment, it reduces to a certain extent the false negative situation that the most commonly used video-based methods may face due to insufficient lighting conditions, exceeding the monitoring range, etc. Therefore, in the foreseeable future, methods based on audio and video fusion are expected to become the best solution for fall detection. Specifically, this article outlines the following methodology: the video-based model utilizes YOLOv7-Pose to extract key skeleton joints, which are then fed into a two stream Spatial Temporal Graph Convolutional Network (ST-GCN) for classification. Meanwhile, the audio-based model employs log-scaled mel spectrograms to capture different features, which are processed through the MobileNetV2 architecture for detection. The final decision fusion of the two results is achieved through linear weighting and Dempster-Shafer (D-S) theory. After evaluation, our multimodal fall detection method significantly outperforms the single modality method, especially the evaluation metric sensitivity increased from 81.67% in single video modality to 96.67% (linear weighting) and 97.50% (D-S theory), which emphasizing the effectiveness of integrating video and audio data to achieve more powerful and reliable fall detection in complex and diverse daily life environments.

Plant thermosensors.

Plants dynamically regulate their genes expression and physiological outputs to adapt to changing temperatures. The underlying molecular mechanisms have been extensively studied in diverse plants and in multiple dimensions. However, the question of exactly how temperature is detected at molecular level to transform the physical information into recognizable intracellular signals remains continues to be one of the undetermined occurrences in plant science. Recent studies have provided the physical and biochemical mechanistic breakthrough of how temperature changes can influence molecular thermodynamically stability, thus changing molecular structures, activities, interaction and signaling transduction. In this review, we focus on the thermosensing mechanisms of recognized and potential plant thermosensors, to describe the multi-level thermal input system in plants. We also consider the attributes of a thermosensor on the basis of thermal-triggered changes in function, structure, and physical parameters. This study thus provides a reference for discovering more plant thermosensors and elucidating plant thermal adaptive mechanisms.

Formation and prediction of heterocyclic amines and N-nitrosamines in smoked sausages using back propagation artificial neural network.

BACKGROUND: Heterocyclic amines (HAs) and N-nitrosamines (NAs) are formed easily during the thermal processing of food, and epidemiological studies have demonstrated that consuming HAs and NAs increases the risk of cancer. However, there are few studies on the application of back propagation artificial neural network (BP-ANN) models to simultaneously predict the content of HAs and NAs in sausages. This study aimed to investigate the effects of cooking time and temperature, smoking time and temperature, and fat-to-lean ratio on the formation of HAs and NAs in smoked sausages, and to predict their total content based on the BP-ANN model. RESULTS: With an increase in processing time, processing temperature and fat ratio, the content of HAs and NAs in smoked sausages increased significantly, while the content of HA precursors and nitrite residues decreased significantly. The optimal network topology of the BP-ANN model was 5-11-2, the correlation coefficient values for training, validation, testing and all datasets were 0.99228, 0.99785, 0.99520 and 0.99369, respectively, and the mean squared error value of the best validation performance was 0.11326. The bias factor and the accuracy factor were within acceptable limits, and the predicted values approximated the true values, indicating that the model has good predictive performance. CONCLUSION: The contents of HAs and NAs in smoked sausages were significantly influenced by the cooking conditions, smoking conditions and fat ratio. The BP-ANN model has high application value in predicting the contents of HAs and NAs in sausages, which provides a theoretical basis for the suppression of carcinogen formation. © 2024 Society of Chemical Industry.

Prognostic value of serum phosphate levels in sepsis: a systematic review and meta-analysis.

Background: There remain controversies over the conclusion of different serum phosphate levels as prognostic predictors of sepsis patients. As such, this study investigated the association between different serum phosphate and the prognosis of sepsis. Methods: Data from PubMed, Embase, Cochrane Library, and Web of Science were systematically retrieved from the inception of databases to June 1, 2023 and independently screened and extracted by two authors. Binary variables in the study were estimated as relative risk ratio (RR) and 95% confidence interval (CI), and continuous variables were estimated as mean and standard deviation. The Newcastle-Ottawa Scale (NOS) was employed to evaluate the quality of the included studies, and subgroup analysis and sensitivity analysis were performed for all outcomes to explore the sources of heterogeneity. Results: Ten studies were included in this study including 38,320 patients with sepsis or septic shock. Against normal serum phosphate levels, a high serum phosphate level was associated with an elevated all-cause mortality risk (RR = 1.46; 95% CI [1.22-1.74]; P = 0.000) and prolonged Intensive Care Unit (ICU) length of stay (LOS) (WMD = 0.63; 95% CI [0.27-0.98]; P = 0.001). However, there was no significant difference in the in-hospital LOS (WMD = 0.22; 95% CI [-0.61-1.05]; P = 0.609). A low serum phosphate level was not significantly associated with the all-cause mortality risk (RR = 0.97; 95% CI [0.86-1.09]; P = 0.588), ICU LOS (WMD = -0.23; 95% CI [-0.75-0.29]; P = 0.394) and in-hospital LOS (WMD = -0.62; 95% CI [-1.72-0.49]; P = 0.274). Conclusion: Sepsis patients with high serum phosphate levels before therapeutic interventions were associated with a significant increase in the all-cause mortality risk, prolonged ICU LOS, and no significant difference in in-hospital LOS. Sepsis patients with low serum phosphate levels before interventions may have a reduced risk of all-cause mortality, shorter ICU LOS, and in-hospital LOS, but the results were not statistically significant.

Efficient and safe use of a slow-release Mn material for three sequential crops of rice in Cd-contaminated paddy soils.

Traditional passivators reduce the effectiveness of Cd by ion exchange, chemisorption, and complexation in soil. However, traditional passivators have defects such as easy aging and poor durability, which not only reduce the treatment efficiency but also increase the risk of primary soil environmental pollution. For this reason, considering that Mn and Cd have physiological antagonism in rice, sepiolite-supported manganese ferrite (SMF) was prepared in this study to improve passivation persistence. The passivation mechanism, effect and duration of SMF were explored. The results showed that SMF has a dense and small pore structure and that the surface is rough, which provides abundant adsorption sites for Cd2+ adsorption. When the SMF adsorbs Cd2+, ions or functional groups in the material, such as MnOOH*, will exchange with Cd2+ to form Cd(OH)2 and other internal complexes. Indoor pure soil cultivation experiments showed that 0.1 % SMF can reduce the effective Cd content of soil by 41.32 %, demonstrating the efficiency of SMF. The three-crop rice experiments in pots showed that SMF could increase soil pH and continuously increase the content of available Mn in soil. Increasing the content of available Mn reduces the ability of rice to absorb Cd. In addition, the three-cropping rice experiments also indicated that the passivation effect of SMF materials on Cd-contaminated paddy fields was long-lasting and stable and that SMF is a more efficient and safe Cd passivation agent.

[Effects of Source Depletion on Vapor Intrusion Risk Assessment].

The current regulatory site investigation employs the J&E model to predict vapor intrusion risk. However, the J&E model assumes that the source concentration is constant for a given exposure period, which is not consistent with the actual site source under depletion. In this study, we compared the differences between the J&E model (constant source), SD source depletion model, and RBCA source depletion model for predicting indoor concentration variation as well as the risk levels during the exposure period with a case study in Beijing. The results showed that the source and indoor air concentrations predicted by the SD and RBCA models showed exponential decreases, whereas those predicted by the J&E model maintained high concentrations throughout the exposure period, which greatly overestimated the risk. The RBCA predicted source depletion at the fastest rate, but the predicted indoor air concentrations were still lower than those of the SD model, which was related to the fact that the RBCA did not consider the effect of buildings on source depletion and did not follow mass conservation. Further, the sensitivity analysis showed that the pressure difference (dP) had the greatest influence on the source concentration in the SD model. For the calculated carcinogenic risk and hazard quotients, the J&E constant source model, the SD source depletion model, and the RBCA source depletion model were ranked in descending order. The results indicated that in general the J&E model was too conservative, the RBCA model may have underestimated risk, and the SD model was more suitable for quantifying vapor intrusion risk in reality.

Response of soil phosphorus fractions to litter removal in subalpine coniferous forest.

Litter plays a crucial role in phosphorus (P) cycling, and its role in forest ecosystems may vary with different treatments and forest types. In this study, we investigated soil P fraction responses to litter removal in different forest types and how forest conversion affects the acquisition pathway of bioavailable P through an in situ controlled litter experiment. The results showed that the soil P content increased with the conversion of primary to secondary forest, which may be mostly related to the differences in nutrients and species richness between the two forest types. In addition, the main source of bioavailable P in primary forests was active organic P, while mineral P was the main bioavailable P source in secondary forests. Moreover, the three-year litter removal treatment significantly decreased the primary forest soil P fraction content while significantly increasing the secondary forest bioavailable P content. The main driving factors of the soil P fraction are also different between the two forest types, with AP activity and SOC as the major factors in the primary forest and pH as the main factor in the secondary forest.

Mechanism for improving the gel properties of transglutaminase-mediated porcine myofibrillar protein by ultrasonic pretreatment combined with carrageenan.

To improve the limitation of transglutaminase on the quality of myofibrillar protein (MP) gel, this study investigated the synergistic effect of ultrasonic pretreatment in combination with carrageenan on the gel properties of transglutaminase-mediated MP gels. The synergistic effect generated gel with lower surface hydrophobicity and fluorescence intensity. Combined with the secondary structure results, it can be hypothesized that the synergistic effect caused the rearrangement of the proteins and the formation of aggregates wrapping hydrophobic groups, which changed the structure and phase behavior of the proteins. The synergistic effect also improved the formation of dense and interpenetrating gel networks, which reduced cooking loss and produced composite MP gels with optimal gel strength. Moreover, FTIR spectroscopy revealed the presence of electrostatic interactions in the hybrid gel system. This study provides a theoretical basis and experimental foundation for the effective use of high-tech composite functional components to improve the quality of gel products.

Species richness disparity in tropical terrestrial herbaceous floras: Evolutionary insight from Collabieae (Orchidaceae).

Species richness is spatially heterogeneous even in the hyperdiverse tropical floras. The main cause of uneven species richness among the four tropical regions are hot debated. To date, higher net diversification rates and/or longer colonization time have been usually proposed to contribute to this pattern. However, there are few studies to clarify the species richness patterns in tropical terrestrial floras. The terrestrial tribe Collabieae (Orchidaceae) unevenly distributes in the tropical regions with a diverse and endemic center in Asia. Twenty-one genera 127 species of Collabieae and 26 DNA regions were used to reconstruct the phylogeny and infer the biogeographical processes. We compared the topologies, diversification rates and niche evolutionary rates of Collabieae and regional lineages on empirical samplings and different simulated samplings fractions respectively. Our results suggested that the Collabieae originated in Asia at the earliest Oligocene, and then independently spread to Africa, Central America, and Oceania since the Miocene via long-distance dispersal. These results based on empirical data and simulated data were similar. BAMM, GeoSSE and niche analyses inferred that the Asian lineages had higher net diversification and niche evolutionary rates than those of Oceanian and African lineages on the empirical and simulated analyses. Precipitation is the most important factor for Collabieae, and the Asian lineage has experienced more stable and humid climate, which may promote the higher net diversification rate. Besides, the longer colonization time may also be associated with the Asian lineages' diversity. These findings provided a better understanding of the regional diversity heterogeneity in tropical terrestrial herbaceous floras.

Identification of orphan histidine kinases that impact sporulation and enterotoxin production by Clostridium perfringens type F strain SM101 in a pathophysiologically-relevant ex vivo mouse intestinal contents model.

When causing food poisoning or antibiotic-associated diarrhea, Clostridium perfringens type F strains must sporulate to produce C. perfringens enterotoxin (CPE) in the intestines. C. perfringens is thought to use some of its seven annotated orphan histidine kinases to phosphorylate Spo0A and initiate sporulation and CPE production. We previously demonstrated the CPR0195 orphan kinase, but not the putative CPR1055 orphan kinase, is important when type F strain SM101 initiates sporulation and CPE production in modified Duncan-Strong (MDS) sporulation medium. Since there is no small animal model for C. perfringens sporulation, the current study used diluted mouse intestinal contents (MIC) to develop an ex vivo sporulation model and employed this model to test sporulation and CPE production by SM101 CPR0195 and CPR1055 null mutants in a pathophysiologically-relevant context. Surprisingly, both mutants still sporulated and produced CPE at wild-type levels in MIC. Therefore, five single null mutants were constructed that cannot produce one of the previously-unstudied putative orphan kinases of SM101. Those mutants implicated CPR1316, CPR1493, CPR1953 and CPR1954 in sporulation and CPE production by SM101 MDS cultures. Phosphorylation activity was necessary for CPR1316, CPR1493, CPR1953 and CPR1954 to affect sporulation in those MDS cultures, supporting their identity as kinases. Importantly, only the CPR1953 or CPR1954 null mutants exhibited significantly reduced levels of sporulation and CPE production in MIC cultures. These phenotypes were reversible by complementation. Characterization studies suggested that, in MDS or MIC, the CPR1953 and CPR1954 mutants produce less Spo0A than wild-type SM101. In addition, the CPR1954 mutant exhibited little or no Spo0A phosphorylation in MDS cultures. These studies, i) highlight the importance of using pathophysiologically-relevant models to investigate C. perfringens sporulation and CPE production in a disease context and ii) link the CPR1953 and CPR1954 kinases to C. perfringens sporulation and CPE production in disease-relevant conditions.

NanJ Is the Major Sialidase for Clostridium perfringens Type F Food Poisoning Strain 01E809.

Clostridium perfringens type F strains cause food poisoning (FP) when they sporulate and produce C. perfringens enterotoxin (CPE) in the intestines. Most type F FP strains carry a chromosomal cpe gene (c-cpe strains). C. perfringens produces up to three different sialidases, named NanH, NanI, and NanJ, but some c-cpe FP strains carry only nanJ and nanH genes. This study surveyed a collection of such strains and showed that they produce sialidase activity when cultured in Todd-Hewitt broth (TH) (vegetative cultures) or modified Duncan-Strong (MDS) medium (sporulating cultures). Sialidase null mutants were constructed in 01E809, a type F c-cpe FP strain carrying the nanJ and nanH genes. Characterization of those mutants identified NanJ as the major sialidase of 01E809 and showed that, in vegetative and sporulating cultures, nanH expression affects nanJ expression and vice versa; those regulatory effects may involve media-dependent changes in transcription of the codY or ccpA genes but not nanR. Additional characterization of these mutants demonstrated the following: (i) NanJ contributions to growth and vegetative cell survival are media dependent, with this sialidase increasing 01E809 growth in MDS but not TH; (ii) NanJ enhances 24-h vegetative cell viability in both TH and MDS cultures; and (iii) NanJ is important for 01E809 sporulation and, together with NanH, CPE production in MDS cultures. Lastly, NanJ was shown to increase CPE-induced cytotoxicity and CH-1 pore formation in Caco-2 cells. Collectively, these results suggest that NanJ may have a contributory role in FP caused by type F c-cpe strains that carry the nanH and nanJ genes.

Diagnostic Significance of Targeted Next-Generation Sequencing in Central Nervous System Infections in Neurosurgery of Pediatrics.

Background: Cerebrospinal fluid (CSF) pathogen culture suffers from the drawbacks of prolonged cycle time and a low positivity rate in diagnosing intracranial infections in children. This study aims to investigate the diagnostic potential of targeted next-generation sequencing (tNGS) in pediatric neurosurgery for central nervous system (CNS) infections. Methods: A retrospective study was conducted on children under 14 with suspected intracranial infections following craniocerebral trauma or surgery between November 2018 and August 2020. Routine, biochemical, smear, and pathogen culture tests were performed on CSF during treatment. The main parameters of CSF analysis encompassed white blood cells (WBC, ×106/L) count, percentage of multinucleated cells (%), protein levels (g/L), glucose concentration (GLU, mmol/L), chloride levels (mmol/L), and pressure (mmH2O). The outcomes of tNGS were assessed through the Receiver Operating Characteristic (ROC) curve and pertinent diagnostic parameters. Results: Among the 35 included pediatric patients, 22 were clinically diagnosed with CNS infection in neurosurgery, tNGS was confirmed in 18 cases. The sensitivity and specificity of tNGS were 81.8% and 76.9%, respectively, while the traditional method of CSF cultures and smears exhibited a sensitivity of 13.6% and a specificity of 100%. ROC curve analysis indicated an area under the curve (AUC) of 0.794 for tNGS and 0.568 for the CSF cultures and smears. CSF analysis indicated that the two groups exhibited statistically significant differences in terms of WBC count [330.0 (110.00-2639.75) vs 14.00 (4.50-26.50), P<0.001] and percentage of multinuclear cells (%) [87.50 (39.75-90.00) vs 0 (0-10.00), P<0.001]. However, the remaining parameters did not statistically significant differences between the groups (all P>0.05). Conclusion: tNGS demonstrates a high degree of diagnostic accuracy when detecting infections within the CNS of pediatric neurosurgery patients. tNGS can effectively establish for diagnosing CNS infections by detecting pathogenic microorganisms and their corresponding virulence and/or resistance genes within the test samples.

Electrospun naringin-loaded microsphere/sucrose acetate isobutyrate system promotes macrophage polarization toward M2 and facilitates osteoporotic bone defect repair.

Repairing osteoporotic bone defects is still a major clinical challenge. Recent studies have revealed that immune response is also essential in osteogenesis. The intrinsic inflammatory response of the host, especially the M1/M2 polarization status and inflammatory secretory function of macrophages, can directly affect osteogenic differentiation. Therefore, in this study, an electrospun naringin-loaded microspheres/sucrose acetate isobutyrate (Ng-m-SAIB) system was constructed to investigate its effect on the polarization of macrophage and osteoporotic bone defects. The results of both in vitro and in vivo experiments showed that Ng-m-SAIB had good biocompatibility and could promote the polarization of macrophage toward M2, thereby forming a favorable microenvironment for osteogenesis. The animal experiments also showed that Ng-m-SAIB could promote the osteogenesis of critical size defects in the skull of the osteoporotic model mouse (the senescence-accelerated mouse-strain P6). Together, these results collectively suggested that Ng-m-SAIB might be a promising biomaterial to treat osteoporotic bone defects with favorable osteo-immunomodulatory effects.

Formation of the synaptonemal complex in a gynogenetic allodiploid hybrid fish.

Introduction: The correct pairing and separation of homologous chromosomes during meiosis is crucial to ensure both genetic stability and genetic diversity within species. In allodiploid organisms, synapsis often fails, leading to sterility. However, a gynogenetic allodiploid hybrid clone line (GDH), derived by crossing red crucian carp (Carassius auratus ♀) and common carp (Cyprinus carpio ♂), stably produces diploid eggs. Because the GDH line carries 100 chromosomes with 50 chromosomes from the red crucian carp (RCC; ♀, 2n = 2x = 100) and 50 chromosomes from the common carp (CC; C. carpio L., ♂, 2n = 2x = 100), it is interesting to study the mechanisms of homologous chromosome pairing during meiosis in GDH individuals. Methods: By using fluorescence in situ hybridization (FISH) with a probe specific to the red crucian carp to label homologous chromosomes, we identified the synaptonemal complex via immunofluorescence assay of synaptonemal complex protein 3 (SCP3). Results: FISH results indicated that, during early ovarian development, the GDH oogonium had two sets of chromosomes with only one set from Carassius auratus, leading to the failure formation of normal bivalents and the subsequently blocking of meiosis. This inhibition lasted at least 5 months. After this long period of inhibition, pairs of germ cells fused, doubling the chromosomes such that the oocyte contained two sets of chromosomes from each parent. After chromosome doubling at 10 months old, homologous chromosomes and the synaptonemal complex were identified. Discussion: Causally, meiosis proceeded normally and eventually formed diploid germ cells. These results further clarify the mechanisms by which meiosis proceeds in hybrids.

Exploring island syndromes: Variable matrix permeability in Phalaenopsis pulcherrima (Orchidaceae), a specialist lithophyte of tropical Asian inselbergs.

Introduction: Plants confined to island-like habitats are hypothesised to possess a suite of functional traits that promote on-spot persistence and recruitment, but this may come at the cost of broad-based colonising potential. Ecological functions that define this island syndrome are expected to generate a characteristic genetic signature. Here we examine genetic structuring in the orchid Phalaenopsis pulcherrima, a specialist lithophyte of tropical Asian inselbergs, both at the scale of individual outcrops and across much of its range in Indochina and on Hainan Island, to infer patterns of gene flow in the context of an exploration of island syndrome traits. Methods: We sampled 323 individuals occurring in 20 populations on 15 widely scattered inselbergs, and quantified genetic diversity, isolation-by-distance and genetic structuring using 14 microsatellite markers. To incorporate a temporal dimension, we inferred historical demography and estimated direction of gene flow using Bayesian approaches. Results: We uncovered high genotypic diversity, high heterozygosity and low rates of inbreeding, as well as strong evidence for the occurrence of two genetic clusters, one comprising the populations of Hainan Island and the other those of mainland Indochina. Connectivity was greater within, rather than between the two clusters, with the former unequivocally supported as ancestral. Discussion: Despite a strong capacity for on-spot persistence conferred by clonality, incomplete self-sterility and an ability to utilize multiple magnet species for pollination, our data reveal that P. pulcherrima also possesses traits that promote landscape-scale gene flow, including deceptive pollination and wind-borne seed dispersal, generating an ecological profile that neither fully conforms to, nor fully contradicts, a putative island syndrome. A terrestrial matrix is shown to be significantly more permeable than open water, with the direction of historic gene flow indicating that island populations can serve as refugia for postglacial colonisation of continental landmasses by effective dispersers.

Variations and patterns of C and N stoichiometry in the first five root branch orders across 218 woody plant species.

Despite the vital role in carbon (C) sequestration and nutrient retention, variations and patterns in root C and nitrogen (N) stoichiometry of the first five root orders across woody plant species remains unclear. We compiled a dataset to explore variations and patterns of root C and N stoichiometry in the first five orders of 218 woody plant species. Across the five orders, root N concentrations were greater in deciduous, broadleaf, and arbuscular mycorrhizal species than in evergreen, coniferous species, and ectomycorrhizal association species, respectively. Contrasting trends were found for root C : N ratios. Most root branch orders showed clear latitudinal and altitudinal trends in root C and N stoichiometry. There were opposite patterns in N concentrations between latitude and altitude. Such variations were mainly driven by plant species, and climatic factors together. Our results indicate divergent C and N use strategies among plant types and convergence and divergence in the patterns of C and N stoichiometry between latitude and altitude across the first five root orders. These findings provide important data on the root economics spectrum and biogeochemical models to improve understanding and prediction of climate change effects on C and nutrient dynamics in terrestrial ecosystems.