Systems Biology

Metabolic Connectome and Its Role in the Prediction, Diagnosis, and Treatment of Complex Diseases

Fri, 2024-02-23 06:00

Metabolites. 2024 Jan 26;14(2):93. doi: 10.3390/metabo14020093.

ABSTRACT

The interconnectivity of advanced biological systems is essential for their proper functioning. In modern connectomics, biological entities such as proteins, genes, RNA, DNA, and metabolites are often represented as nodes, while the physical, biochemical, or functional interactions between them are represented as edges. Among these entities, metabolites are particularly significant as they exhibit a closer relationship to an organism's phenotype compared to genes or proteins. Moreover, the metabolome has the ability to amplify small proteomic and transcriptomic changes, even those from minor genomic changes. Metabolic networks, which consist of complex systems comprising hundreds of metabolites and their interactions, play a critical role in biological research by mediating energy conversion and chemical reactions within cells. This review provides an introduction to common metabolic network models and their construction methods. It also explores the diverse applications of metabolic networks in elucidating disease mechanisms, predicting and diagnosing diseases, and facilitating drug development. Additionally, it discusses potential future directions for research in metabolic networks. Ultimately, this review serves as a valuable reference for researchers interested in metabolic network modeling, analysis, and their applications.

PMID:38392985 | DOI:10.3390/metabo14020093

Categories: Literature Watch

Temperature Dependence of Platelet Metabolism

Fri, 2024-02-23 06:00

Metabolites. 2024 Jan 26;14(2):91. doi: 10.3390/metabo14020091.

ABSTRACT

Temperature plays a fundamental role in biology, influencing cellular function, chemical reaction rates, molecular structures, and interactions. While the temperature dependence of many biochemical reactions is well defined in vitro, the effect of temperature on metabolic function at the network level is poorly understood, and it remains an important challenge in optimizing the storage of cells and tissues at lower temperatures. Here, we used time-course metabolomic data and systems biology approaches to characterize the effects of storage temperature on human platelets (PLTs) in a platelet additive solution. We observed that changes to the metabolome with storage time do not simply scale with temperature but instead display complex temperature dependence, with only a small subset of metabolites following an Arrhenius-type relationship. Investigation of PLT energy metabolism through integration with computational modeling revealed that oxidative metabolism is more sensitive to temperature changes than glycolysis. The increased contribution of glycolysis to ATP turnover at lower temperatures indicates a stronger glycolytic phenotype with decreasing storage temperature. More broadly, these results demonstrate that the temperature dependence of the PLT metabolic network is not uniform, suggesting that efforts to improve the health of stored PLTs could be targeted at specific pathways.

PMID:38392983 | DOI:10.3390/metabo14020091

Categories: Literature Watch

The Exometabolome of <em>Xylella fastidiosa</em> in Contact with <em>Paraburkholderia phytofirmans</em> Supernatant Reveals Changes in Nicotinamide, Amino Acids, Biotin, and Plant Hormones

Fri, 2024-02-23 06:00

Metabolites. 2024 Jan 24;14(2):82. doi: 10.3390/metabo14020082.

ABSTRACT

Microbial competition within plant tissues affects invading pathogens' fitness. Metabolomics is a great tool for studying their biochemical interactions by identifying accumulated metabolites. Xylella fastidiosa, a Gram-negative bacterium causing Pierce's disease (PD) in grapevines, secretes various virulence factors including cell wall-degrading enzymes, adhesion proteins, and quorum-sensing molecules. These factors, along with outer membrane vesicles, contribute to its pathogenicity. Previous studies demonstrated that co-inoculating X. fastidiosa with the Paraburkholderia phytofirmans strain PsJN suppressed PD symptoms. Here, we further investigated the interaction between the phytopathogen and the endophyte by analyzing the exometabolome of wild-type X. fastidiosa and a diffusible signaling factor (DSF) mutant lacking quorum sensing, cultivated with 20% P. phytofirmans spent media. Liquid chromatography-mass spectrometry (LC-MS) and the Method for Metabolite Annotation and Gene Integration (MAGI) were used to detect and map metabolites to genomes, revealing a total of 121 metabolites, of which 25 were further investigated. These metabolites potentially relate to host adaptation, virulence, and pathogenicity. Notably, this study presents the first comprehensive profile of X. fastidiosa in the presence of a P. phytofirmans spent media. The results highlight that P. phytofirmans and the absence of functional quorum sensing affect the ratios of glutamine to glutamate (Gln:Glu) in X. fastidiosa. Additionally, two compounds with plant metabolism and growth properties, 2-aminoisobutyric acid and gibberellic acid, were downregulated when X. fastidiosa interacted with P. phytofirmans. These findings suggest that P. phytofirmans-mediated disease suppression involves modulation of the exometabolome of X. fastidiosa, impacting plant immunity.

PMID:38392974 | DOI:10.3390/metabo14020082

Categories: Literature Watch

Pins Gene Table v2.0: An Online Genome Database of 37 <em>Pythium insidiosum</em> Strains for Gene Content Exploration and Phylogenomic Analysis

Fri, 2024-02-23 06:00

J Fungi (Basel). 2024 Jan 29;10(2):112. doi: 10.3390/jof10020112.

ABSTRACT

Unlike most pathogenic oomycetes, Pythium insidiosum infects humans and animals instead of plants. P. insidiosum has three clinically relevant genotypes/clades that cause a severe disease called pythiosis. To develop strategies for infection control, it is necessary to understand the biology and pathogenesis of this pathogen. Investigating the evolutionary mechanisms behind the host-specific adaptation is vital, and comparative genomic analysis can help with this. To facilitate genomic analysis, an online bioinformatics tool called P. insidiosum (Pins) Gene Table v2.0 was developed. This tool includes genomic data from 37 genetically diverse P. insidiosum strains and four related species. The database contains 732,686 genes, grouped into 80,061 unique clusters and further divided into core and variable categories at genus, species, and genotype levels. A high-resolution phylogenomic relationship among P. insidiosum strains and other oomycetes was projected through hierarchical clustering and core gene analyses. 3156 P. insidiosum-specific genes were shared among all genotypes and may be responsible for causing disease in humans and animals. After comparing these species-specific genes to the MvirDB database, 112 had significant matches with 66 known virulence proteins, some of which might be involved in vascular occlusion, which is a pathological feature of pythiosis. The correlation of genotypes, geographic origins, and affected hosts of P. insidiosum suggests that clade-I strains are more specific to animals, while clade-II/III strains are more specific to humans. The clade-specific genes might link to host preference. In summary, Pins Gene Table v2.0 is a comprehensive genome database accessible to users with minimal bioinformatics experience for the analysis of P. insidiosum genomes.

PMID:38392784 | DOI:10.3390/jof10020112

Categories: Literature Watch

Possible Role of Fibrinaloid Microclots in Postural Orthostatic Tachycardia Syndrome (POTS): Focus on Long COVID

Fri, 2024-02-23 06:00

J Pers Med. 2024 Jan 31;14(2):170. doi: 10.3390/jpm14020170.

ABSTRACT

Postural orthostatic tachycardia syndrome (POTS) is a common accompaniment of a variety of chronic, inflammatory diseases, including long COVID, as are small, insoluble, 'fibrinaloid' microclots. We here develop the argument, with accompanying evidence, that fibrinaloid microclots, through their ability to block the flow of blood through microcapillaries and thus cause tissue hypoxia, are not simply correlated with but in fact, by preceding it, may be a chief intermediary cause of POTS, in which tachycardia is simply the body's exaggerated 'physiological' response to hypoxia. Similar reasoning accounts for the symptoms bundled under the term 'fatigue'. Amyloids are known to be membrane disruptors, and when their targets are nerve membranes, this can explain neurotoxicity and hence the autonomic nervous system dysfunction that contributes to POTS. Taken together as a system view, we indicate that fibrinaloid microclots can serve to link POTS and fatigue in long COVID in a manner that is at once both mechanistic and explanatory. This has clear implications for the treatment of such diseases.

PMID:38392604 | DOI:10.3390/jpm14020170

Categories: Literature Watch

A Mechanistic Model of Perceptual Binding Predicts That Binding Mechanism Is Robust against Noise

Fri, 2024-02-23 06:00

Entropy (Basel). 2024 Jan 31;26(2):133. doi: 10.3390/e26020133.

ABSTRACT

The concept of the brain's own time and space is central to many models and theories that aim to explain how the brain generates consciousness. For example, the temporo-spatial theory of consciousness postulates that the brain implements its own inner time and space for conscious processing of the outside world. Furthermore, our perception and cognition of time and space can be different from actual time and space. This study presents a mechanistic model of mutually connected processes that encode phenomenal representations of space and time. The model is used to elaborate the binding mechanism between two sets of processes representing internal space and time, respectively. Further, a stochastic version of the model is developed to investigate the interplay between binding strength and noise. Spectral entropy is used to characterize noise effects on the systems of interacting processes when the binding strength between them is varied. The stochastic modeling results reveal that the spectral entropy values for strongly bound systems are similar to those for weakly bound or even decoupled systems. Thus, the analysis performed in this study allows us to conclude that the binding mechanism is noise-resilient.

PMID:38392388 | DOI:10.3390/e26020133

Categories: Literature Watch

Interventions to Mitigate Financial Toxicity in Adult Patients with Cancer in the United States: A Scoping Review

Fri, 2024-02-23 06:00

Curr Oncol. 2024 Feb 6;31(2):918-932. doi: 10.3390/curroncol31020068.

ABSTRACT

Financial toxicity adversely affects quality of life and treatment outcomes for patients with cancer. This scoping review examined interventions aimed at mitigating financial toxicity in adult patients with cancer and their effectiveness. We utilized five bibliographical databases to identify studies that met our inclusion criteria. The review included studies conducted among adult patients with cancer in the United States and published in English between January 2011 to March 2023. The review identified eight studies that met the inclusion criteria. Each of the studies discussed the implementation of interventions at the patient/provider and/or health system level. Collectively, the findings from this scoping review highlight both the limited number of published studies that are aimed at mitigating financial toxicity and the need to create and assess interventions that directly impact financial toxicity in demographically diverse populations of adult patients with cancer.

PMID:38392062 | DOI:10.3390/curroncol31020068

Categories: Literature Watch

The landscape of transcription factor promoter activity during vegetative development in Marchantia

Fri, 2024-02-23 06:00

Plant Cell. 2024 Feb 23:koae053. doi: 10.1093/plcell/koae053. Online ahead of print.

ABSTRACT

Transcription factors (TFs) are essential for the regulation of gene expression and cell fate determination. Characterising the transcriptional activity of TF genes in space and time is a critical step towards understanding complex biological systems. The vegetative gametophyte meristems of bryophytes share some characteristics with the shoot apical meristems of flowering plants. However, the identity and expression profiles of TFs associated with gametophyte organization are largely unknown. With only ∼450 putative TF genes, Marchantia (Marchantia polymorpha) is an outstanding model system for plant systems biology. We have generated a near-complete collection of promoter elements derived from Marchantia TF genes. We experimentally tested reporter fusions for all the TF promoters in the collection and systematically analysed expression patterns in Marchantia gemmae. This allowed us to build a map of expression domains in early vegetative development and identify a set of TF-derived promoters that are active in the stem cell zone. The cell markers provide additional tools and insight into the dynamic regulation of the gametophytic meristem and its evolution. In addition, we provide an online database of expression patterns for all promoters in the collection. We expect that these promoter elements will be useful for cell-type-specific expression, synthetic biology applications, and functional genomics.

PMID:38391349 | DOI:10.1093/plcell/koae053

Categories: Literature Watch

Boosting species evenness, productivity and weed control in a mixed meadow by promoting arbuscular mycorrhizas

Fri, 2024-02-23 06:00

Front Plant Sci. 2024 Feb 8;15:1303750. doi: 10.3389/fpls.2024.1303750. eCollection 2024.

ABSTRACT

Lowland meadows represent aboveground and belowground biodiversity reservoirs in intensive agricultural areas, improving water retention and filtration, ensuring forage production, contrasting erosion and contributing to soil fertility and carbon sequestration. Besides such major ecosystem services, the presence of functionally different plant species improves forage quality, nutritional value and productivity, also limiting the establishment of weeds and alien species. Here, we tested the effectiveness of a commercial seed mixture in restoring a lowland mixed meadow in the presence or absence of inoculation with arbuscular mycorrhizal (AM) fungi and biostimulation of symbiosis development with the addition of short chain chito-oligosaccharides (CO). Plant community composition, phenology and productivity were regularly monitored alongside AM colonization in control, inoculated and CO-treated inoculated plots. Our analyses revealed that the CO treatment accelerated symbiosis development significantly increasing root colonization by AM fungi. Moreover, the combination of AM fungal inoculation and CO treatment improved plant species evenness and productivity with more balanced composition in forage species. Altogether, our study presented a successful and scalable strategy for the reintroduction of mixed meadows as valuable sources of forage biomass; demonstrated the positive impact of CO treatment on AM development in an agronomic context, extending previous observations developed under controlled laboratory conditions and leading the way to the application in sustainable agricultural practices.

PMID:38390295 | PMC:PMC10883063 | DOI:10.3389/fpls.2024.1303750

Categories: Literature Watch

Sustained and Localized Drug Depot Release using Radiation-Activated Scintillating Nanoparticles

Fri, 2024-02-23 06:00

Adv Mater. 2024 Feb 23:e2312326. doi: 10.1002/adma.202312326. Online ahead of print.

ABSTRACT

Clinical treatment of cancer commonly incorporates X-ray radiation therapy (XRT), and developing spatially-precise radiation-activatable drug delivery strategies may improve XRT efficacy while limiting off-target toxicities associated with systemically administered drugs. Nevertheless, achieving this has been challenging thus far because strategies typically rely on radical species with short lifespans, and the inherent nature of hypoxic and acidic tumor microenvironments may encourage spatially heterogeneous effects. We hypothesized that the challenge could be bypassed by using scintillating nanoparticles that emit light upon X-ray absorption, locally forming therapeutic drug depots in tumor tissues. We thus developed a nanoparticle platform ( Scintillating nanoparticle Drug Depot; SciDD) that enables the local release of cytotoxic payloads only after activation by XRT, thereby limiting off-target toxicity. As a proof-of-principle, SciDD was used to deliver a microtubule-destabilizing payload MMAE (monomethyl auristatin E). With as little as a 2 Gy local irradiation to tumors, MMAE payloads were released effectively to kill tumor cells. XRT-mediated drug release was demonstrated in multiple mouse cancer models and showed efficacy over XRT alone (p < 0.0001). This work shows that SciDD can act as a local drug depot with spatiotemporally controlled release of cancer therapeutics. This article is protected by copyright. All rights reserved.

PMID:38389502 | DOI:10.1002/adma.202312326

Categories: Literature Watch

Optimization of plasmid electrotransformation into Bacillus subtilis using an antibacterial peptide

Thu, 2024-02-22 06:00

Arch Microbiol. 2024 Feb 22;206(3):116. doi: 10.1007/s00203-024-03847-2.

ABSTRACT

Bacillus subtilis can potentially serve as an efficient expression host for biotechnology due to its ability to secrete extracellular proteins and enzymes directly into the culture medium. One of the important challenges in the biotechnology industry is to optimize the transformation conditions of B. subtilis bacteria. This study aims to provide a new method to optimize the transformation conditions and improve the transformation efficiency of B. subtilis WB600. To increase the transformation efficiency in B. subtilis, two methods of adding CM11 antibacterial peptides to the bacterial medium along with electroporation and optimizing the variables including the growth medium composition, time to adding CM11 peptide, electroporation voltage, recovery medium, and cell recovery time are used. The results of this study showed that the addition of antimicrobial peptides (AMPs) with a concentration of 2 μg/ml increases the transformation efficiency by 4 times compared to the absence of AMP in the bacterial medium. Additionally, the findings from our study indicated that the most optimal rate of transformation for B. subtilis was observed at a voltage of 7.5 kV/cm, with a recovery period of 12 h. With the optimized method, the transformation efficiency came up to 1.69 × 104 CFU/µg DNA. This improvement in transformation efficiency will be attributed to the research of expression of exogenous genes in B. subtilis, gene library construction for transformation of wild-type B. subtilis strains.

PMID:38388903 | DOI:10.1007/s00203-024-03847-2

Categories: Literature Watch

Chromosome evolution screens recapitulate tissue-specific tumor aneuploidy patterns

Thu, 2024-02-22 06:00

Nat Genet. 2024 Feb 22. doi: 10.1038/s41588-024-01665-2. Online ahead of print.

ABSTRACT

Whole chromosome and arm-level copy number alterations occur at high frequencies in tumors, but their selective advantages, if any, are poorly understood. Here, utilizing unbiased whole chromosome genetic screens combined with in vitro evolution to generate arm- and subarm-level events, we iteratively selected the fittest karyotypes from aneuploidized human renal and mammary epithelial cells. Proliferation-based karyotype selection in these epithelial lines modeled tissue-specific tumor aneuploidy patterns in patient cohorts in the absence of driver mutations. Hi-C-based translocation mapping revealed that arm-level events usually emerged in multiples of two via centromeric translocations and occurred more frequently in tetraploids than diploids, contributing to the increased diversity in evolving tetraploid populations. Isogenic clonal lineages enabled elucidation of pro-tumorigenic mechanisms associated with common copy number alterations, revealing Notch signaling potentiation as a driver of 1q gain in breast cancer. We propose that intrinsic, tissue-specific proliferative effects underlie tumor copy number patterns in cancer.

PMID:38388848 | DOI:10.1038/s41588-024-01665-2

Categories: Literature Watch

The CNK-HYP scaffolding complex promotes RAF activation by enhancing KSR-MEK interaction

Thu, 2024-02-22 06:00

Nat Struct Mol Biol. 2024 Feb 22. doi: 10.1038/s41594-024-01233-6. Online ahead of print.

ABSTRACT

The RAS-MAPK pathway regulates cell proliferation, differentiation and survival, and its dysregulation is associated with cancer development. The pathway minimally comprises the small GTPase RAS and the kinases RAF, MEK and ERK. Activation of RAF by RAS is notoriously intricate and remains only partially understood. There are three RAF isoforms in mammals (ARAF, BRAF and CRAF) and two related pseudokinases (KSR1 and KSR2). RAS-mediated activation of RAF depends on an allosteric mechanism driven by the dimerization of its kinase domain. Recent work on human RAFs showed that MEK binding to KSR1 promotes KSR1-BRAF heterodimerization, which leads to the phosphorylation of free MEK molecules by BRAF. Similar findings were made with the single Drosophila RAF homolog. Here we show that the fly scaffold proteins CNK and HYP stabilize the KSR-MEK interaction, which in turn enhances RAF-KSR heterodimerization and RAF activation. The cryogenic electron microscopy structure of the minimal KSR-MEK-CNK-HYP complex reveals a ring-like arrangement of the CNK-HYP complex allowing CNK to simultaneously engage KSR and MEK, thus stabilizing the binary interaction. Together, these results illuminate how CNK contributes to RAF activation by stimulating the allosteric function of KSR and highlight the diversity of mechanisms impacting RAF dimerization as well as the regulatory potential of the KSR-MEK interaction.

PMID:38388830 | DOI:10.1038/s41594-024-01233-6

Categories: Literature Watch

Author Correction: A heterotypic assembly mechanism regulates CHIP E3 ligase activity

Thu, 2024-02-22 06:00

EMBO J. 2024 Feb 22. doi: 10.1038/s44318-024-00042-3. Online ahead of print.

NO ABSTRACT

PMID:38388749 | DOI:10.1038/s44318-024-00042-3

Categories: Literature Watch

Protein design using structure-based residue preferences

Thu, 2024-02-22 06:00

Nat Commun. 2024 Feb 22;15(1):1639. doi: 10.1038/s41467-024-45621-4.

ABSTRACT

Recent developments in protein design rely on large neural networks with up to 100s of millions of parameters, yet it is unclear which residue dependencies are critical for determining protein function. Here, we show that amino acid preferences at individual residues-without accounting for mutation interactions-explain much and sometimes virtually all of the combinatorial mutation effects across 8 datasets (R2 ~ 78-98%). Hence, few observations (~100 times the number of mutated residues) enable accurate prediction of held-out variant effects (Pearson r > 0.80). We hypothesized that the local structural contexts around a residue could be sufficient to predict mutation preferences, and develop an unsupervised approach termed CoVES (Combinatorial Variant Effects from Structure). Our results suggest that CoVES outperforms not just model-free methods but also similarly to complex models for creating functional and diverse protein variants. CoVES offers an effective alternative to complicated models for identifying functional protein mutations.

PMID:38388493 | DOI:10.1038/s41467-024-45621-4

Categories: Literature Watch

Spatiotemporal patterns of the pregnancy microbiome and links to reproductive disorders

Thu, 2024-02-22 06:00

Sci Bull (Beijing). 2024 Feb 6:S2095-9273(24)00070-7. doi: 10.1016/j.scib.2024.02.001. Online ahead of print.

ABSTRACT

The microbiome of females undergoes extensive remodeling during pregnancy, which is likely to have an impact on the health of both mothers and offspring. Nevertheless, large-scale integrated investigations characterizing microbiome dynamics across key body habitats are lacking. Here, we performed an extensive meta-analysis that compiles and analyzes microbiome profiles from >10,000 samples across the gut, vagina, and oral cavity of pregnant women from diverse geographical regions. We have unveiled unexpected variations in the taxonomic, functional, and ecological characteristics of microbial communities throughout the course of pregnancy. The gut microbiota showed distinct trajectories between Western and non-Western populations. The vagina microbiota exhibited fluctuating transitions at the genus level across gestation, while the oral microbiota remained relatively stable. We also identified distinctive microbial signatures associated with prevalent pregnancy-related disorders, including opposite variations in the oral and gut microbiota of patients with gestational diabetes and disrupted microbial networks in preterm birth. This study establishes a comprehensive atlas of the pregnancy microbiome by integrating multidimensional datasets and offers foundational insights into the intricate interplay between microbes and host factors that underlie reproductive health.

PMID:38388298 | DOI:10.1016/j.scib.2024.02.001

Categories: Literature Watch

Unraveling the signaling roles of indole in an opportunistic pathogen Pseudomonas aeruginosa strain Jade-X

Thu, 2024-02-22 06:00

Chemosphere. 2024 Feb 20:141482. doi: 10.1016/j.chemosphere.2024.141482. Online ahead of print.

ABSTRACT

Pseudomonas aeruginosa, which can produce several toxins and form biofilm, is listed among the priority pathogens. Indole is a ubiquitous aromatic pollutant and signaling molecule produced by tryptophanase in bacteria. Herein, the impacts of indole on a newly isolated P. aeruginosa strain Jade-X were systematically investigated. Indole (0.5-2.0 mM) enhanced the biofilm production by 1.33-2.31-fold after 24 h incubation at 30 °C. However, the effects indole on biofilm formation were intricate and closely intertwined with factors such as incubation temperature, bacterial growth stage, and indole concentration. The twitching motility was enhanced by 1.15-1.99-fold by indole, potentially facilitating surface exploration and biofilm development. Indole reduced the production of virulence factors (pyocyanin and pyoverdine) as well as altered the surface properties (zeta potential and hydrophobicity). Transcriptional analysis revealed that indole (1.0 mM) significantly downregulated mexGHI-opmD efflux genes (4.73-6.91-fold) and virulence-related genes (pqs, pch, and pvd clusters, and flagella-related genes), while upregulating pili-related genes in strain Jade-X. The quorum sensing related signal regulators, including RhlR, LasR, and MvfR (PqsR), were not altered by indole, while other six transcriptional regulators (AmrZ, BfmR, PchR, QscR, SoxR, and SphR) were significantly affected, implying that indole effects might be regulated in a complex and delicate manner. This study should provide new insights into our understanding of indole signaling roles.

PMID:38387666 | DOI:10.1016/j.chemosphere.2024.141482

Categories: Literature Watch

Single-cell colocalization analysis using a deep generative model

Thu, 2024-02-22 06:00

Cell Syst. 2024 Feb 21;15(2):180-192.e7. doi: 10.1016/j.cels.2024.01.007.

ABSTRACT

Analyzing colocalization of single cells with heterogeneous molecular phenotypes is essential for understanding cell-cell interactions, and cellular responses to external stimuli and their biological functions in diseases and tissues. However, existing computational methodologies identified the colocalization patterns between predefined cell populations, which can obscure the molecular signatures arising from intercellular communication. Here, we introduce DeepCOLOR, a computational framework based on a deep generative model that recovers intercellular colocalization networks with single-cell resolution by the integration of single-cell and spatial transcriptomes. Along with colocalized population detection accuracy that is superior to existing methods in simulated dataset, DeepCOLOR identified plausible cell-cell interaction candidates between colocalized single cells and segregated cell populations defined by the colocalization relationships in mouse brain tissues, human squamous cell carcinoma samples, and human lung tissues infected with SARS-CoV-2. DeepCOLOR is applicable to studying cell-cell interactions behind various spatial niches. A record of this paper's transparent peer review process is included in the supplemental information.

PMID:38387441 | DOI:10.1016/j.cels.2024.01.007

Categories: Literature Watch

Impact of wildfire recurrence on soil properties and organic carbon fractions

Thu, 2024-02-22 06:00

J Environ Manage. 2024 Feb 21;354:120293. doi: 10.1016/j.jenvman.2024.120293. Online ahead of print.

ABSTRACT

The recurrence and severity of wildfire is on the rise due to factors like global warming and human activities. Mediterranean regions are prone to significant wildfire events, which cause extensive damage to ecosystems and soil properties. This study focuses on the municipality of Allande in south-western Asturias (Spain), a region highly affected by recurrent wildfires. In this regard, we sought to examine how the recurrence of such fires influences soil organic carbon fractionation and other soil parameters, such as nitrogen fractionation, pH, and cation exchange capacity. The study involved six sampling plots with between varying fire recurrence levels, from 0 to 4 events between 2005 and 2022. The results revealed some significant effects of wildfires recurrence on soil texture, inorganic elemental composition and CEC, but not on pH and CE. In soil affected by recurrent fires, labile carbon fractions (cold-water extractable & hot-water extractable), and fulvic acid concentrations decreased by up to 36%, 5%, and 45%, respectively in comparison with undisturbed soil. In contrast, humic acid concentration remained stable or increased in soils damaged by fire. Additionally, nitrogen species in soil were observed to decrease significantly in high recurrence scenarios, especially nitrate. On the basis of our findings, we conclude that wildfires impact the distinct fractions of organic carbon and nitrogen in soils and that this effect is aggravated by increasing recurrence.

PMID:38387345 | DOI:10.1016/j.jenvman.2024.120293

Categories: Literature Watch

Patterns of recombination in snakes reveal a tug-of-war between PRDM9 and promoter-like features

Thu, 2024-02-22 06:00

Science. 2024 Feb 23;383(6685):eadj7026. doi: 10.1126/science.adj7026. Epub 2024 Feb 23.

ABSTRACT

In some mammals, notably humans, recombination occurs almost exclusively where the protein PRDM9 binds, whereas in vertebrates lacking an intact PRDM9, such as birds and canids, recombination rates are elevated near promoter-like features. To determine whether PRDM9 directs recombination in nonmammalian vertebrates, we focused on an exemplar species with a single, intact PRDM9 ortholog, the corn snake (Pantherophis guttatus). Analyzing historical recombination rates along the genome and crossovers in pedigrees, we found evidence that PRDM9 specifies the location of recombination events, but we also detected a separable effect of promoter-like features. These findings reveal that the uses of PRDM9 and promoter-like features need not be mutually exclusive and instead reflect a tug-of-war that is more even in some species than others.

PMID:38386752 | DOI:10.1126/science.adj7026

Categories: Literature Watch

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