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opencc-zeroSep 2021View details →

Pleistocene climatic fluctuations promoted alternative evolutionary histories in Phytelephas aequatorialis, an endemic palm from western Ecuador

Aim: Pleistocene (2.58 Ma – 11.7 ka) climatic fluctuations have shaped intraspecific genetic patterns worldwide; however, their manifestation in many regions remains unknown. In order to determine the impact of Pleistocene climatic fluctuations on the tropical rain forests of western Ecuador, we explored the evolutionary history of the endemic palm Phytelephas aequatorialis. Location: Western Ecuador, northwestern South America. Taxon: Phytelephas aequatorialis (Arecaceae). Methods: 176 nuclear genes were sequenced in 91 individuals for phylogenomic and population structure analyses. The time of divergence between identified genetic lineages was estimated using a coalescent phylogenomic analysis. Paleoecological niche modelling analyses were performed to determine areas of historical climatic suitability since the Last Glacial Maximum (LGM; 22 ka) that potentially acted as forest refugia during the Pleistocene. A Wilcoxon test and Pearson correlations were used to explore how current levels of genetic diversity (Hs) have been shaped by several paleoclimatic and geographic factors. Results: Phylogenomic and population structure analyses revealed two genetic lineages with a north-south distribution, which diverged 1.14 Ma during the Pleistocene. Two potential Pleistocene refugia were identified in the Pacific coast of Ecuador and in the Andean foothills of southwestern Ecuador, whose distribution agrees with the spatial location of the two lineages. Within the Andean foothills, Hs was lower for the southern lineage than for the northern lineage. Hs significantly increased with decreasing latitude within the whole species distribution. Main conclusions: Pleistocene climatic fluctuations promoted intraspecific divergence in P. aequatorialis within the rain forests of western Ecuador. The Andean foothills of southwestern Ecuador could be an important spot for rain forest evolution because they potentially remained climatically suitable through the Pleistocene. Lower genetic diversity in the southern lineage, which apparently remained isolated in the Andean foothills during glacial cycles, adds evidence to the presence of a forest refugium in southwestern Ecuador. The geographic pattern in genetic diversity suggests that P. aequatorialis colonized western Ecuador from the north. This study supports the role of Pleistocene climatic fluctuations in promoting intraspecific divergence, and for the first time, we show their impact west of the Andes.

opencc-zeroOct 2021View details →

Development and validation of the Health Belief Model questionnaire to promote smoking cessation for nasopharyngeal cancer prevention: a cross-sectional study

Objective: Nasopharyngeal cancer (NPC) risk factors caused by lifestyle choices are substantial yet avoidable. Using the Health Belief Model as a conceptual framework, this study develops and validates a questionnaire to predict smokers' intentions to quit in Sarawak, Malaysia (HBM). Design: A cross sectional study. Setting: Urban and suburban areas in Sarawak, Malaysia. Participants: Following a thorough literature study, the preliminary items for the instrument were created. Prior to beginning the content validity by a panel of 10 experts, the instrument was translated into the Malay language utilising the forward-backwards approach. 10 smokers carried out face validity in both quantitative and qualitative ways. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were used to assess the instrument's concept validity. Phase 1 of the EFA involved 100 smokers, whereas phase 2 of the CFA involved 171 smokers. Cronbach's alpha coefficients were used to measure internal consistency and assess reliability. Results: The factor loading of each item remained within the acceptable threshold in the exploratory stage. The final revised CFA yielded the following model fit indices that suitably fitted the seven-factor model: Chi Square: 641.705; df= 500; P< 0.001; CFI = 0.953; TLI: 0.948; RMSEA= 0.041. With the exception of one pairwise construct, satisfactory convergent validity and divergent validity were demonstrated. Phases 1 and 2 both have Cronbach's alpha values over 0.7, suggesting acceptable internal reliability. Conclusions: The study confirmed the validity and reliability of the instrument in predicting smokers' tendency to adopt healthy behaviour of smoking cessation to lower risk of developing cancer. The instrument consists of 34 items, dividing into two sections: 6 HBM components and health behavioural intention. The instrument is regarded as innovation and can be applicable in other smoking-related malignancies in different susceptible populations and geographical locations.

opencc-by-4.0May 2019View details →

Raw Data supporting Promoters adopt distinct dynamic manifestations depending on transcription factor context

All source data is provided as MAT-files, which can be opened in Matlab. In total, the source data contain 270 core data files and 540 processed data files. The data for each individual promoter is stored in a different directory and the 9 promoters are: <ul> <li> ALD3 </li> <li> DCS2 </li> <li> DDR2 </li> <li> HXK1 </li> <li> RTN2 </li> <li> TKL2 </li> <li> SIP18 </li> <li> pSIP18_mut6 (also referred to as mutant A4) </li> <li> pSIP18_mut21 (also referred to as mutant D6) </li> </ul> The data for the first 7 promoters was previously reported in (Hansen and O’Shea, 2013), though in an unnormalized form. That is, it was previously reported as a concentration per cell in arbitrary fluorescence units (AU). In the present manuscript, we have calibrated the data to obtain absolute abundances, such that the MAT-files now contain both the old AU concentration as well as absolute abundances, i.e. number of YFP molecules per cell. The calibration was performed as described in (Huang et al., 2016). Similarly, the data for the last 2 promoters (A4 and D6) was previously reported in its unnormalized form in (Hansen and O’Shea, 2015) and it is here also reported in the form of absolute abundances.   The MAT-files containing the raw data have the suffix “_size.mat”. The name of the MAT files describes the experiment. If the file name contains “DM”, then it is a single pulse. Thus, “SIP18_DM_40min_275nM_size.mat” refers to a single 40 min pulse with 275 nM 1-NM-PP1 for the SIP18 promoter. Similarly if the file name contains “FM”, e.g. “RTN2_FM_8_5min_690nM_size.mat” then it refers to eight 5 min pulses separated by 5 min intervals at 690 nM for the RTN2 promoter. Finally, if the file name contains “FM4”, e.g.  “TKL2_FM4_15minINT_690nM_size.mat” then the experiment was four 5 min pulses separated by 15 min intervals at 690 nM for the TKL2 promoter. The concentration is the concentration of 1-NM-PP1 that was used and 100 nM, 275 nM, 690 nM and 3mM refers to approximately, 25%, 50%, 75% and 100% Msn2 activation. For full experimental details please see (Hansen and O’Shea, 2013; Hansen et al., 2015).   The “_size.mat” MAT-files contain the following variables: <ul> <li> cell_size_pixels</li> <li> CFP</li> <li> CFP_molecules</li> <li> CFP_raw</li> <li> inhibitor_conc</li> <li> MSN2_raw</li> <li> MSN2_RFP</li> <li> pulse_parameters • time</li> <li> YFP</li> <li> YFP_molecules</li> <li> YFP_raw</li> </ul> CFP, CFP_molecules, CFP_raw and YFP, YFP_molecules, YFP_raw are Nx64 matrices, where each row N correspond to a different cell and the 64 columns correspond to the 64 experimentally measured timepoints corresponding to the “time” vector running from -5 min to 152.5 min in increments of 2.5 min and the 1NM-PP1 inhibitor was added at time 0. “CFP_raw” and “YFP_raw” contains raw, uncorrected data, so without photobleaching correction and background subtraction. “CFP” and “YFP” contain corrected data in arbitrary fluorescence units (AU) and report on the concentration (i.e. size normalized). Finally, “CFP_molecules” and “YFP_molecules” contains the total number of CFP and YFP molecules per cell (i.e. this is not a concentration, but the absolute abundance). The area of each cell at each timepoint can be found in the matrix “cell_size_pixels”. Since the cells are live and growing, this will tend to increase during the experiments. Occasionally large fluctuations can occur due to errors in cell segmentation or due to division. For full details on the image analysis and cell segmentation, please see (Hansen and O’Shea, 2013; Hansen et al., 2015).   The variables “inhibitor_conc” and “pulse_parameters” refer to the type of experiment and is also given by the name. “inhibitor_conc”  gives the 1NMPP1 concentration: 100 nM, 275 nM, 690 nM or 3000 nM. “pulse_parameters” contains either 2 or 3 elements and given the dynamical pulse sequence parameters. Column 1 contains the number of pulses and column 2 the duration of the pulses. Column 3 gives the interval between the pulses if more than one pulse is used – otherwise column 3 is zero.   Moreover, on a more technical note it should be noted that the signal-to-noise of the CFP reporter is worse than the YFP reporter. Therefore, we always use the YFP reporter for quantitative analysis. Furthermore, the two other MAT-files “…MSN2.mat” and “…YFP.mat” contain processed data. Please see the ReadMe file on the code for a full description and how these were derived.   Finally, Supplementary Table 1 contains the model-inferred parameters for each promoter and condition.     References Hansen, A.S., and O’Shea, E.K. (2013). Promoter decoding of transcription factor dynamics involves a trade-off between noise and control of gene expression. Mol. Syst. Biol. Hansen, A.S., and O’Shea, E.K. (2015). Cis Determinants of Promoter Threshold and Activation Timescale. Cell Rep. Hansen, A.S., Hao, N., and OShea, E.K. (2015). High-throughput microfluidics to control and measure signaling dynamics in single yeast cells. Nat. Protoc. Huang, L., Pauleve, L., Zechner, C., Unger, M., Hansen, A.S., and Koeppl, H. (2016). Reconstructing dynamic molecular states from single-cell time series. J. R. Soc. Interface.

opencc-zeroNov 2022View details →

Data from: Agroecological measures in meadows promote honey bee colony development and winter survival

The homogenization of agricultural landscapes has led to a decrease in pollinator diversity and abundance. In response to this decline, farmers have implemented agroecological measures, which, in meadows, aim at providing more floral resources. These measures are the availability of unmown floral strips, delayed mowing, and discouraging the use of the conditioner, a device known to harm insects. The aim of our study was to investigate the cascade of effects of these agroecological measures on honey bee colony development and winter survival. We (i) determined the effect of these measures on colony size during the nectar and pollen collecting season in spring and summer, (ii) evaluated the effect of spring and summer colony sizes on autumn size, and (iii) described the effect of colony size in autumn on winter mortality. In this study, 300 honey bee colonies were monitored over three years in three cantons of Switzerland. Colony size was defined by the number of brood cells and adult workers, Honey bee colony size in summer and autumn were improved by agroecological measures on meadows and likely contributed to the increased overwintering success. This study is a first step towards the targeted identification of viable agroecological measures on temporary meadows that can be implemented to promote honey bee colonies' health in the agricultural landscape.

opencc-zeroNov 2022View details →

Airborne cues accelerate flowering and promote photosynthesis in Brassica rapa

1. Volatile cues can induce and/or prime plant defences, but it is less well known if plants also respond by altering growth and reproduction-related parameters. 2. Here we evaluated whether plant volatile cues can elicit changes in growth, flower production, net photosynthesis rate and defences in receiver plants and whether those responses are similar to those elicited in response to direct herbivore-feeding. 3. Our results demonstrate that exposure to volatiles emitted from damaged neighbours accelerated the time to first flowering, increased the number of flowers produced and the net photosynthesis rate, but did not alter the fresh harvested plant biomass and volatile defences, compared to non-exposed plants. Earlier flowering was also observed for plants exposed to volatiles from undamaged plants. 4. These responses differed from those of plants exposed to actual herbivore-feeding for which feeding enhanced net photosynthesis rate but reduced growth and had no effect on reproduction and defence in response to subsequent herbivory. 5. Synthesis. These findings document that plant airborne cues can influence floral traits of receiver plants. In particular, the flower phenology is modulated, and photosynthesis is enhanced, suggesting that carbon allocation could be directed toward reproduction.

opencc-zeroNov 2022View details →

Data from: Augmin prevents merotelic attachments by promoting proper arrangement of bridging and kinetochore fibers

The human mitotic spindle is made of microtubules nucleated at centrosomes, at kinetochores, and from pre-existing microtubules by the augmin complex. However, it is unknown how the augmin-mediated nucleation affects distinct microtubule classes and thereby mitotic fidelity. Here we use superresolution microscopy to analyze the previously indistinguishable microtubule arrangements within the crowded metaphase plate area and demonstrate that augmin is vital for the formation of uniformly arranged parallel units consisting of sister kinetochore fibers connected by a bridging fiber. This ordered geometry helps both prevent and resolve merotelic attachments. Whereas augmin-nucleated bridging fibers prevent merotelic attachments by creating a nearly parallel and highly bundled microtubule arrangement unfavorable for creating additional attachments, augmin-nucleated k-fibers produce robust force required to resolve errors during anaphase. STED microscopy revealed that bridging fibers were impaired twice as much as k-fibers following augmin depletion. The complete absence of bridging fibers from a significant portion of kinetochore pairs, especially in the inner part of the spindle, resulted in the specific reduction of the interkinetochore distance. Taken together, we propose a model where augmin promotes mitotic fidelity by generating assemblies consisting of bridging and kinetochore fibers that align sister kinetochores to face opposite poles, thereby preventing erroneous attachments.

opencc-by-4.0May 2023View details →

[Github Sample Dataset] Microbiota dictate T cell clonal selection to promote graft-vs-host disease after stem cell transplantation

[Github Sample Dataset]. This is an accompanying data set for the github repository "https://github.com/acyeh-lab/2023/tree/main/tcr-simulation" referred to in "Non-genetic determinants of clonotypic T cell expansion following stem cell transplantation" by Yeh AC et al.

opencc-zeroDec 2022View details →

Soluble T-cadherin promotes pancreatic β-cell proliferation by upregulating Notch signaling

Endogenous humoral factors that link systemic and/or local insulin demand to pancreatic β-cells have not been identified. Here, we demonstrated that T-cadherin, a unique glycosylphosphatidylinositol-anchored cadherin primarily expressed in vascular endothelial cells and cardiac and skeletal muscle cells, but not in pancreatic β-cells, was secreted as soluble forms and was important for β-cell proliferation. Cdh13 (T-cadherin) knockout mice exhibited impaired glucose handling due to attenuated β-cell proliferation under high-fat diet conditions. The gene expression analyses indicated the impairment in cell cycle and Notch signaling in the islets of T-cadherin knockout mice under high-fat diet conditions. In streptozotocin-induced diabetes, the replacement of soluble T-cadherin improved β-cell mass and blood glucose levels in T-cadherin knockout mice. Recombinant soluble T-cadherin upregulated Notch signaling in cultured murine islets. We concluded that soluble T-cadherin could work as an endogenous humoral factor whose signaling pathways including Notch signaling regulate β-cell proliferation under diabetic conditions in mice.

opencc-by-4.0Jan 2023View details →

Maryland private school websites' physical activity promotion

Excel file of 387 Maryland (USA) private schools' websites' mentioning of PE (the term physical education, PE teacher, PE curriculum, PE dosage) and physical activity (intramural physical activity, interscholastic sports, physical activity images)

STRA6 promotes thyroid carcinoma progression via activation of the ILK/AKT/mTOR axis in cells and female nude mice

Background: Metastasis has emerged to be an important cause for poor prognosis of thyroid carcinoma (TC) and its molecular mechanisms are not fully understood. STRA6 is a multifunctional membrane protein widely expressed in embryonic and adult tissues. The function and mechanism of STRA6 in TC remain elusive. Objective: We aimed to explore the role of STRA6 in TC progression and provide a therapeutic target for TC. Methods: The expression and clinicopathological relevance of STRA6 were explored in TC. Stable STRA6-knockdown TC cells were established and used to determine the biological function of STRA6 in vitro and in vivo. RNA-sequencing and Co-immunoprecipitation were performed to unveil the molecular mechanism of STRA6 in TC progression. The potential of STRA6 as a therapeutic target was evaluated by lipid nanoparticles (LNPs) containing siRNA. Results: STRA6 was upregulated in TC and correlated with aggressive clinicopathological features including extrathyroidal extension and lymph node metastasis, which contributed to the poor prognosis of TC. STRA6 facilitated TC progression by enhancing proliferation and metastasis in vitro and in vivo. Mechanistically, STRA6 could interact with ILK and subsequently activate the AKT/mTOR signaling pathway. We further unveiled that STRA6 reprogrammed lipid metabolism through SREBP1, which was crucial for the metastasis of TC. Moreover, STRA6 siRNA delivered by LNP significantly inhibited cell growth in xenograft tumor models. Conclusions: Our study demonstrates the critical roles of STRA6 contributing to TC progression via the ILK/AKT/mTOR axis, which may provide a novel prognostic marker as well as a promising therapeutic target for aggressive TC.

opencc-by-4.0Feb 2023View details →

Raw Data for the article: Cigarette smoke promotes inflammasome-independent activation of caspase-1 and -4 leading to gasdermin D cleavage in human macrophages

Mechanisms and consequences of gasdermin D (GSDMD) activation in cigarette smoke (CS)-associated inflammation and lung disease are unknown. GSDMD is a downstream effector of caspase-1, -8, and -4. Upon cleavage, GSDMD generates pores into cell membranes. Different degrees of GSDMD activation are associated with a range of physiological outputs ranging from cell hyperactivation to pyroptosis. We have previously reported that in human monocyte-derived macrophages CS extract (CSE) inhibits the NLRP3 inflammasome and shifts the response to lipopolysaccharide (LPS) towards the TLR4-TRIF axis leading to activation of caspase-8, which, in turn, activates caspase-1. In the present work, we investigated whether other ASC-dependent inflammasomes could be involved in caspase activation by CSE and whether caspase activation led to GSDMD cleavage and other downstream effects. Presented results demonstrate that CSE promoted ASC-independent activation of caspase-1 leading to GSDMD cleavage and increased cell permeability, in the absence of cell death. GSDMD cleavage was strongly enhanced upon stimulation with LPS+CSE, suggesting a synergistic effect between the two stimuli. Noteworthy, CSE promoted LPS internalization leading to caspase-4 activation, thus contributing to increased GSDMD cleavage. Caspase-dependent GSDMD cleavage was associated with mitochondrial superoxide generation. Increased cleaved GSDMD was found in lung macrophages of smokers compared to ex-smokers and non-smoking controls. Our findings revealed that ASC-independent activation of caspase-1, -4, and -8 and GSDMD cleavage upon exposure to CS may contribute to macrophage dysfunction and feed the chronic inflammation observed in the smokers' lung.

Data for: Host shift promotes divergent evolution between closely related holoparasitic species

Distinct hosts have been hypothesized to possess the potential for affecting species differentiation and genome evolution of parasitic organisms. However, what host shift history is experienced by the closely related parasites and whether disparate evolution of their genomes occur remain largely unknown. Here, we screened horizontal gene transfer (HGT) events in a pair of sister species of holoparasitic Boschniakia (Orobanchaceae) having obligate hosts from distinct families to recall the former host-parasite associations and performed a comparative analysis to investigate the difference of their organelle genomes. Except these from present hosts (Ericaceae and Betulaceae), a number of HGTs from Rosaceae were identified to support the occurrence of unexpected ancient host shifts. Different hosts transfer functional genes which changed nuclear genomes of the sister species. Similarly, different donors transfer sequences to their mitogenomes which size varies due to foreign and repetitive elements rather than other factors found in other parasites. The plastomes are both severely reduced, but the extent of differences in reduction syndrome is near to the genus level. Our findings provide new insights into the genome evolution of parasites adapting different hosts and extend the mechanism of host shift promoting species differentiation to parasitic plant lineages.

Data for: Excess labile carbon promotes diazotroph abundance in heat-stressed octocorals

Constant nitrogen limitation is the foundation of a stable coral-algal symbiosis. Diazotrophs, i.e., prokaryotes capable of fixing N2 into ammonia, are key players in coral holobionts. Recent studies on reef-building corals have shown that labile dissolved organic carbon (DOC) enrichment or heat stress stimulated the growth and activity of diazotrophs, resulting in excess nitrogen availability. However, the (a)biotic drivers of diazotrophs in octocorals are still poorly understood. We investigated diazotroph abundance (assessed via relative quantification of nifH gene copy numbers) in two symbiotic octocorals, the more mixotrophic soft coral Xenia umbellata and the more autotrophic gorgonian Pinnigorgia flava, under a) labile DOC enrichment for 21 days, followed by b) combined labile DOC enrichment and heat stress for 24 days. In the absence of heat stress, relative diazotroph abundances in X. umbellata and P. flava were unaffected by DOC enrichment. During heat stress, DOC enrichment (higher than 20 mg glucose L-1) increased the relative abundances of diazotrophs by 6-fold in X. umbellata and 4-fold in P. flava, compared to their counterparts without excess DOC. Our data suggest that labile DOC enrichment and concomitant heat stress could disrupt the nitrogen limitation in octocorals through stimulating diazotroph proliferations. Reducing labile DOC loading may effectively help octocorals cope with future ocean warming scenarios.

Data from: Variable ambient temperature promotes song learning and production in zebra finches

This data set contains the data used in the analysis of the article titled: Variable ambient temperature promotes song learning and production in zebra finches.

opencc-by-4.0Feb 2023View details →

FTD-tau S320F mutation stabilizes local structure and allosterically promotes amyloid motif-dependent aggregation

Amyloid deposition of the microtubule-associated protein tau is a unifying theme in a multitude of neurodegenerative diseases. Disease-associated missense mutations in tau are associated with frontotemporal dementia (FTD) and enhance tau aggregation propensity. However, the molecular mechanism of how mutations in tau promote tau assembly into amyloids remains obscure. There is a need to understand how tau folds into pathogenic conformations to cause disease. Here we describe the structural mechanism for how an FTD-tau S320F mutation drives spontaneous aggregation. We use recombinant protein and synthetic peptide systems, computational modeling, cross-linking mass spectrometry, and cell models to investigate the mechanism of spontaneous aggregation of the S320F FTD-tau mutant. We discover that the S320F mutation drives the stabilization of a local hydrophobic cluster which allosterically exposes the 306VQIVYK311 amyloid motif. We identify a suppressor mutation that reverses the S320F aggregation phenotype through the reduction of S320F-based hydrophobic clustering in vitro and in cells. Finally, we use structure-based computational design to engineer rapidly aggregating tau sequences by optimizing nonpolar clusters in proximity to the S320 site revealing a new principle governing the regulation of tau aggregation. We uncover a mechanism for regulating aggregation that balances transient nonpolar contacts within local protective structures or in longer-range interactions that sequester amyloid motifs. The introduction of a pathogenic mutation redistributes these transient interactions to drive spontaneous aggregation.  We anticipate that more profound knowledge of this process will permit control of tau aggregation into discrete structural polymorphs to aid the design of reagents that can detect disease-specific tau conformations.

opencc-by-4.0Mar 2023View details →

DRAM1 Promotes Lysosomal Delivery of Mycobacterium marinum in Macrophages

Confocal RAW imaging data related to manuscript DRAM1 Promotes Lysosomal Delivery of Mycobacterium marinum in Macrophages.

opencc-by-4.0Mar 2023View details →

The indirect pathway of the basal ganglia promotes transient punishment, but not motor suppression

Data and code for manuscript entitled "The indirect pathway of the basal ganglia promotes transient punishment, but not motor suppression"

opencc-zeroMar 2023View details →

Data for: Climatic oscillation promoted diversification of spinous assassin bugs during Pleistocene glaciation

Insect speciation is among the most fascinating topics in evolutionary biology; however, its underlying mechanisms remain unclear. Allopatric speciation represents one of the major types of speciation and is believed to have frequently occurred during glaciation periods, when climatic oscillation may have caused suitable habitats to be fragmented repeatedly, creating geographical isolation among populations. However, supporting evidence for allopatric speciation of insects in East Asia during the Pleistocene glaciation remains lacking. We aim to investigate the effect of climatic oscillation during the Pleistocene glaciation on the diversification pattern and evolutionary history of hemipteran insects and to test the hypothesis of Pleistocene species stability using spinous assassin bugs Sclomina (Hemiptera: Reduviidae), a small genus widely distributed in southern China but was lately found to have cryptic species diversity. Here, using the whole mitochondrial genome (mitogenome) and nuclear ribosomal RNA genes, we investigated both interspecific and intraspecific diversification patterns of spinous assassin bugs. Approximate Bayesian computation, ecological niche modeling and demographic history analyses were also applied to understand the diversification process and driven factors. Our data suggest that the five species of Sclomina are highly diverged, despite three of them currently being cryptic. Speciation occurred during Pleistocene when suitable distribution areas were possibly fragmentated. Six phylogeographic groups in the type species S. erinacea were identified, among which two groups underwent expansion during early Last Glacial Period and after Last Glacier Maximum. Our analyses suggest that this genus may have experienced climate-driven habitat fragmentation and post-glacial expansion in the Pleistocene, promoting allopatric speciation and intraspecific diversification. Our results reveal underestimated species diversity in a small insect group and illustrate a remarkable example of allopatric speciation of insects in East Asia promoted by Pleistocene climatic oscillations. These findings provide important insights into the speciation processes and aid the conservation of insect species diversity.

opencc-zeroApr 2023View details →

Do plant-soil feedbacks promote coexistence in a sagebrush steppe?

Recent studies have shown the potential for negative plant-soil feedbacks (PSFs) to promote stable coexistence but have not quantified the stabilizing effect relative to other coexistence mechanisms. We conducted a field experiment to test the role of PSFs in stabilizing coexistence among four dominant sagebrush steppe species that appear to coexist stably, based on previous work with observational data and models. We then integrated the effects of PSF treatments on focal species across germination, survival, and first-year growth. To contribute to stable coexistence, soil microbes should have host-specific effects that result in negative feedbacks. Over two replicated growing seasons, our experiments consistently showed that soil microbes have negative effects on plant growth, but these effects were rarely host-specific. The uncommon host-specific effects were mostly positive at the germination stage and negative for growth. Integrated effects of PSF across early life-stage vital rates showed that PSF-mediated self-limitation occasionally had large effects on projected plant biomass but occurred inconsistently between years. Our results suggest that while microbially-mediated PSF may not be a common mechanism of coexistence in this community, it may still affect the relative abundance of dominant plant species via changes in host fitness. Our work also serves as a blueprint for future investigations that aim to identify underlying processes and test alternative mechanisms to explain important patterns in community ecology.