Systems Biology
Editorial: The plant cell wall: advances and current perspectives
Front Plant Sci. 2023 Jun 22;14:1235749. doi: 10.3389/fpls.2023.1235749. eCollection 2023.
NO ABSTRACT
PMID:37426983 | PMC:PMC10325644 | DOI:10.3389/fpls.2023.1235749
Two plant-associated <em>Bacillus velezensis</em> strains selected after genome analysis, metabolite profiling, and with proved biocontrol potential, were enhancing harvest yield of coffee and black pepper in large field trials
Front Plant Sci. 2023 Jun 23;14:1194887. doi: 10.3389/fpls.2023.1194887. eCollection 2023.
ABSTRACT
Elimination of chemically synthesized pesticides, such as fungicides and nematicides, in agricultural products is a key to successful practice of the Vietnamese agriculture. We describe here the route for developing successful biostimulants based on members of the Bacillus subtilis species complex. A number of endospore-forming Gram-positive bacterial strains with antagonistic action against plant pathogens were isolated from Vietnamese crop plants. Based on their draft genome sequence, thirty of them were assigned to the Bacillus subtilis species complex. Most of them were assigned to the species Bacillus velezensis. Whole genome sequencing of strains BT2.4 and BP1.2A corroborated their close relatedness to B. velezensis FZB42, the model strain for Gram-positive plant growth-promoting bacteria. Genome mining revealed that at least 15 natural product biosynthesis gene clusters (BGCs) are well conserved in all B. velezensis strains. In total, 36 different BGCs were identified in the genomes of the strains representing B. velezensis, B. subtilis, Bacillus tequilensis, and Bacillus. altitudinis. In vitro and in vivo assays demonstrated the potential of the B. velezensis strains to enhance plant growth and to suppress phytopathogenic fungi and nematodes. Due to their promising potential to stimulate plant growth and to support plant health, the B. velezensis strains TL7 and S1 were selected as starting material for the development of novel biostimulants, and biocontrol agents efficient in protecting the important Vietnamese crop plants black pepper and coffee against phytopathogens. The results of the large-scale field trials performed in the Central Highlands in Vietnam corroborated that TL7 and S1 are efficient in stimulating plant growth and protecting plant health in large-scale applications. It was shown that treatment with both bioformulations resulted in prevention of the pathogenic pressure exerted by nematodes, fungi, and oomycetes, and increased harvest yield in coffee, and pepper.
PMID:37426979 | PMC:PMC10327441 | DOI:10.3389/fpls.2023.1194887
Identification and characterization of CYP71 subclade cytochrome P450 enzymes involved in the biosynthesis of bitterness compounds in <em>Cichorium intybus</em>
Front Plant Sci. 2023 Jun 22;14:1200253. doi: 10.3389/fpls.2023.1200253. eCollection 2023.
ABSTRACT
Industrial chicory (Cichorium intybus var. sativum) and witloof (C. intybus var. foliosum) are crops with an important economic value, mainly cultivated for inulin production and as a leafy vegetable, respectively. Both crops are rich in nutritionally relevant specialized metabolites with beneficial effects for human health. However, their bitter taste, caused by the sesquiterpene lactones (SLs) produced in leaves and taproot, limits wider applications in the food industry. Changing the bitterness would thus create new opportunities with a great economic impact. Known genes encoding enzymes involved in the SL biosynthetic pathway are GERMACRENE A SYNTHASE (GAS), GERMACRENE A OXIDASE (GAO), COSTUNOLIDE SYNTHASE (COS) and KAUNIOLIDE SYNTHASE (KLS). In this study, we integrated genome and transcriptome mining to further unravel SL biosynthesis. We found that C. intybus SL biosynthesis is controlled by the phytohormone methyl jasmonate (MeJA). Gene family annotation and MeJA inducibility enabled the pinpointing of candidate genes related with the SL biosynthetic pathway. We specifically focused on members of subclade CYP71 of the cytochrome P450 family. We verified the biochemical activity of 14 C. intybus CYP71 enzymes transiently produced in Nicotiana benthamiana and identified several functional paralogs for each of the GAO, COS and KLS genes, pointing to redundancy in and robustness of the SL biosynthetic pathway. Gene functionality was further analyzed using CRISPR/Cas9 genome editing in C. intybus. Metabolite profiling of mutant C. intybus lines demonstrated a successful reduction in SL metabolite production. Together, this study increases our insights into the C. intybus SL biosynthetic pathway and paves the way for the engineering of C. intybus bitterness.
PMID:37426959 | PMC:PMC10324620 | DOI:10.3389/fpls.2023.1200253
hdWGCNA identifies co-expression networks in high-dimensional transcriptomics data
Cell Rep Methods. 2023 Jun 12;3(6):100498. doi: 10.1016/j.crmeth.2023.100498. eCollection 2023 Jun 26.
ABSTRACT
Biological systems are immensely complex, organized into a multi-scale hierarchy of functional units based on tightly regulated interactions between distinct molecules, cells, organs, and organisms. While experimental methods enable transcriptome-wide measurements across millions of cells, popular bioinformatic tools do not support systems-level analysis. Here we present hdWGCNA, a comprehensive framework for analyzing co-expression networks in high-dimensional transcriptomics data such as single-cell and spatial RNA sequencing (RNA-seq). hdWGCNA provides functions for network inference, gene module identification, gene enrichment analysis, statistical tests, and data visualization. Beyond conventional single-cell RNA-seq, hdWGCNA is capable of performing isoform-level network analysis using long-read single-cell data. We showcase hdWGCNA using data from autism spectrum disorder and Alzheimer's disease brain samples, identifying disease-relevant co-expression network modules. hdWGCNA is directly compatible with Seurat, a widely used R package for single-cell and spatial transcriptomics analysis, and we demonstrate the scalability of hdWGCNA by analyzing a dataset containing nearly 1 million cells.
PMID:37426759 | PMC:PMC10326379 | DOI:10.1016/j.crmeth.2023.100498
Immuno-PET Imaging of CD69 Visualizes T-Cell Activation and Predicts Survival Following Immunotherapy in Murine Glioblastoma
Cancer Res Commun. 2023 Jul 6;3(7):1173-1188. doi: 10.1158/2767-9764.CRC-22-0434. eCollection 2023 Jul.
ABSTRACT
Glioblastoma (GBM) is the most common and malignant primary brain tumor in adults. Immunotherapy may be promising for the treatment of some patients with GBM; however, there is a need for noninvasive neuroimaging techniques to predict immunotherapeutic responses. The effectiveness of most immunotherapeutic strategies requires T-cell activation. Therefore, we aimed to evaluate an early marker of T-cell activation, CD69, for its use as an imaging biomarker of response to immunotherapy for GBM. Herein, we performed CD69 immunostaining on human and mouse T cells following in vitro activation and post immune checkpoint inhibitors (ICI) in an orthotopic syngeneic mouse glioma model. CD69 expression on tumor-infiltrating leukocytes was assessed using single-cell RNA sequencing (scRNA-seq) data from patients with recurrent GBM receiving ICI. Radiolabeled CD69 Ab PET/CT imaging (CD69 immuno-PET) was performed on GBM-bearing mice longitudinally to quantify CD69 and its association with survival following immunotherapy. We show CD69 expression is upregulated upon T-cell activation and on tumor-infiltrating lymphocytes (TIL) in response to immunotherapy. Similarly, scRNA-seq data demonstrated elevated CD69 on TILs from patients with ICI-treated recurrent GBM as compared with TILs from control cohorts. CD69 immuno-PET studies showed a significantly higher tracer uptake in the tumors of ICI-treated mice compared with controls. Importantly, we observed a positive correlation between survival and CD69 immuno-PET signals in immunotherapy-treated animals and established a trajectory of T-cell activation by virtue of CD69-immuno-PET measurements. Our study supports the potential use of CD69 immuno-PET as an immunotherapy response assessment imaging tool for patients with GBM.
SIGNIFICANCE: Immunotherapy may hold promise for the treatment of some patients with GBM. There is a need to assess therapy responsiveness to allow the continuation of effective treatment in responders and to avoid ineffective treatment with potential adverse effects in the nonresponders. We demonstrate that noninvasive PET/CT imaging of CD69 may allow early detection of immunotherapy responsiveness in patients with GBM.
PMID:37426447 | PMC:PMC10324623 | DOI:10.1158/2767-9764.CRC-22-0434
(Tn5-)FISH-based imaging in the era of 3D/spatial genomics
Biophys Rep. 2023 Feb 28;9(1):15-25. doi: 10.52601/bpr.2023.220025.
ABSTRACT
3D genomics mainly focuses on the 3D position of single genes at the cell level, while spatial genomics focuses more on the tissue level. In this exciting new era of 3D/spatial genomics, half-century old FISH and its derivative methods, including Tn5-FISH, play important roles. In this review, we introduce the Tn5-FISH we developed recently, and present six different applications published by our collaborators and us, based on (Tn5-)FISH, which can be either general BAC clone-based FISH or Tn5-FISH. In these interesting cases, (Tn5-)FISH demonstrated its vigorous ability of targeting sub-chromosomal structures across different diseases and cell lines (leukemia, mESCs (mouse embryonic stem cells), and differentiation cell lines). Serving as an effective tool to image genomic structures at the kilobase level, Tn5-FISH holds great potential to detect chromosomal structures in a high-throughput manner, thus bringing the dawn for new discoveries in the great era of 3D/spatial genomics.
PMID:37426200 | PMC:PMC10323772 | DOI:10.52601/bpr.2023.220025
A guide for developing comprehensive systems biology maps of disease mechanisms: planning, construction and maintenance
Front Bioinform. 2023 Jun 22;3:1197310. doi: 10.3389/fbinf.2023.1197310. eCollection 2023.
ABSTRACT
As a conceptual model of disease mechanisms, a disease map integrates available knowledge and is applied for data interpretation, predictions and hypothesis generation. It is possible to model disease mechanisms on different levels of granularity and adjust the approach to the goals of a particular project. This rich environment together with requirements for high-quality network reconstruction makes it challenging for new curators and groups to be quickly introduced to the development methods. In this review, we offer a step-by-step guide for developing a disease map within its mainstream pipeline that involves using the CellDesigner tool for creating and editing diagrams and the MINERVA Platform for online visualisation and exploration. We also describe how the Neo4j graph database environment can be used for managing and querying efficiently such a resource. For assessing the interoperability and reproducibility we apply FAIR principles.
PMID:37426048 | PMC:PMC10325725 | DOI:10.3389/fbinf.2023.1197310
A comprehensive survey of bat sarbecoviruses across China in relation to the origins of SARS-CoV and SARS-CoV-2
Natl Sci Rev. 2022 Oct 11;10(6):nwac213. doi: 10.1093/nsr/nwac213. eCollection 2023 Jun.
ABSTRACT
SARS-CoV and SARS-CoV-2 have been thought to originate from bats. In this study, we screened pharyngeal and anal swabs from 13 064 bats collected between 2016 and 2021 at 703 locations across China for sarbecoviruses, covering almost all known southern hotspots, and found 146 new bat sarbecoviruses. Phylogenetic analyses of all available sarbecoviruses show that there are three different lineages-L1 as SARS-CoV-related CoVs (SARSr-CoVs), L2 as SARS-CoV-2-related CoVs (SC2r-CoVs) and novel L-R (recombinants of L1 and L2)-present in Rhinolophus pusillus bats, in the mainland of China. Among the 146 sequences, only four are L-Rs. Importantly, none belong in the L2 lineage, indicating that circulation of SC2r-CoVs in China might be very limited. All remaining 142 sequences belong in the L1 lineage, of which YN2020B-G shares the highest overall sequence identity with SARS-CoV (95.8%). The observation suggests endemic circulations of SARSr-CoVs, but not SC2r-CoVs, in bats in China. Geographic analysis of the collection sites in this study, together with all published reports, indicates that SC2r-CoVs may be mainly present in bats of Southeast Asia, including the southern border of Yunnan province, but absent in all other regions within China. In contrast, SARSr-CoVs appear to have broader geographic distribution, with the highest genetic diversity and sequence identity to human sarbecoviruses along the southwest border of China. Our data provide the rationale for further extensive surveys in broader geographical regions within, and beyond, Southeast Asia in order to find the most recent ancestors of human sarbecoviruses.
PMID:37425654 | PMC:PMC10325003 | DOI:10.1093/nsr/nwac213
Catalase as a novel drug target for metastatic castration-resistant prostate cancer
Am J Cancer Res. 2023 Jun 15;13(6):2644-2656. eCollection 2023.
ABSTRACT
Prostate Cancer (PCa) is the second most prevalent cancer in the world. Currently, most treatments for PCa involve Androgen Deprivation Therapy (ADT) which inhibits androgen-dependent tumor cell growth. When PCa is diagnosed early and is still Androgen Dependent, ADT is effective. However, this therapy is not effective for metastatic Castration-Resistant Prostate Cancer (mCRPC). Although the mechanism of becoming Castration-Resistant is not fully understood, it is known that high levels of oxidative stress (OS) are important for cancer suppression. Catalase is a very important enzyme in controlling OS levels. We hypothesized that catalase function is critical for the progression to mCRPC. To test this hypothesis, we used a CRISPR nickase system to create a catalase knockdown in PC3 cells, a mCRPC human-derived cell line. We obtained a Cat+/- knockdown cell line, which has approximately half of the transcripts for catalase, half of the protein levels, and half of catalase activity. The Cat+/- cells are also about twice as sensitive to H2O2 exposure compared to WT cells, migrate poorly, have low attachment to collagen, high attachment to Matrigel, and proliferate slowly. Using SCID mice for a xenograft model, we show that Cat+/- cells form smaller tumors than wild-type tumors with less collagen and no blood vessels. These results were validated via rescue experiments where functional catalase was reintroduced into the Cat+/- cells and the phenotypes were reversed. This study shows a novel role for catalase in deterring mCRPC development and points to a new potential drug target for mCRPC progression. Summary: Novel treatments for Metastatic Castration-Resistant Prostate Cancer are needed. By taking advantage of the sensitivity of tumor cells to oxidative stress (OS), reducing an enzyme, catalase, that decreases OS, has the potential to provide another target for Prostate Cancer therapy.
PMID:37424804 | PMC:PMC10326582
Correction: Recent five-year progress in the impact of gut microbiota on vaccination and possible mechanisms
Gut Pathog. 2023 Jul 10;15(1):34. doi: 10.1186/s13099-023-00560-1.
NO ABSTRACT
PMID:37424033 | DOI:10.1186/s13099-023-00560-1
Reinhart Heinrich: In memoriam of an exceptional scholar
Biosystems. 2023 Jul 7:104965. doi: 10.1016/j.biosystems.2023.104965. Online ahead of print.
ABSTRACT
In the Mathematical Biology community, Reinhart Heinrich (1946-2006) is well-known as one of the founders of Metabolic Control Analysis. Moreover, he made significant contributions on the modelling of erythrocyte metabolism and signal transduction cascades, optimality principles in metabolism, theoretical membrane biophysics and other topics. Here, the historical context of his scientific work is outlined and numerous personal memories of the scholarship of, and cooperation with, Reinhart Heinrich are narrated. Attention is drawn again to the pros and cons of normalized and non-normalized control coefficients. The role of the Golden Ratio in a dynamic optimization problem in genetic regulation of metabolism is discussed. Overall, this article is aimed at keeping alive the memory of a unique university teacher, researcher and friend.
PMID:37423594 | DOI:10.1016/j.biosystems.2023.104965
Atypical network topologies enhance the reductive capacity of pathogen thiol antioxidant defense networks
Redox Biol. 2023 Jul 4;65:102802. doi: 10.1016/j.redox.2023.102802. Online ahead of print.
ABSTRACT
Infectious diseases are a significant health burden for developing countries, particularly with the rise of multidrug resistance. There is an urgent need to elucidate the factors underlying the persistence of pathogens such as Mycobacterium tuberculosis, Plasmodium falciparum and Trypanosoma brucei. In contrast to host cells, these pathogens traverse multiple and varied redox environments during their infectious cycles, including exposure to high levels of host-derived reactive oxygen species. Pathogen antioxidant defenses such as the peroxiredoxin and thioredoxin systems play critical roles in the redox stress tolerance of these cells. However, many of the kinetic rate constants obtained for the pathogen peroxiredoxins are broadly similar to their mammalian homologs and therefore, their contributions to the redox tolerances within these cells are enigmatic. Using graph theoretical analysis, we show that compared to a canonical Escherichia coli redoxin network, pathogen redoxin networks contain unique network connections (motifs) between their thioredoxins and peroxiredoxins. Analysis of these motifs reveals that they increase the hydroperoxide reduction capacity of these networks and, in response to an oxidative insult, can distribute fluxes into specific thioredoxin-dependent pathways. Our results emphasize that the high oxidative stress tolerance of these pathogens depends on both the kinetic parameters for hydroperoxide reduction and the connectivity within their thioredoxin/peroxiredoxin systems.
PMID:37423162 | DOI:10.1016/j.redox.2023.102802
Design, synthesis and evaluation of novel 2-phenyl-3-(1H-pyrazol-4-yl)pyridine positive allosteric modulators for the M<sub>4</sub> mAChR
Eur J Med Chem. 2023 Jul 1;258:115588. doi: 10.1016/j.ejmech.2023.115588. Online ahead of print.
ABSTRACT
Translation of muscarinic acetylcholine receptor (mAChR) agonists into clinically used therapeutic agents has been difficult due to their poor subtype selectivity. M4 mAChR subtype-selective positive allosteric modulators (PAMs) may provide better therapeutic outcomes, hence investigating their detailed pharmacological properties is crucial to advancing them into the clinic. Herein, we report the synthesis and comprehensive pharmacological evaluation of M4 mAChR PAMs structurally related to 1e, Me-C-c, [11C]MK-6884 and [18F]12. Our results show that small structural changes to the PAMs can result in pronounced differences to baseline, potency (pEC50) and maximum effect (Emax) measures in cAMP assays when compared to the endogenous ligand acetylcholine (ACh) without the addition of the PAMs. Eight selected PAMs were further assessed to determine their binding affinity and potential signalling bias profile between cAMP and β-arrestin 2 recruitment. These rigorous analyses resulted in the discovery of the novel PAMs, 6k and 6l, which exhibit improved allosteric properties compared to the lead compound, and probative in vivo exposure studies in mice confirmed that they maintain the ability to cross the blood-brain barrier, making them more suitable for future preclinical assessment.
PMID:37423123 | DOI:10.1016/j.ejmech.2023.115588
Cellular allostatic load is linked to increased energy expenditure and accelerated biological aging
Psychoneuroendocrinology. 2023 Jun 14;155:106322. doi: 10.1016/j.psyneuen.2023.106322. Online ahead of print.
ABSTRACT
Stress triggers anticipatory physiological responses that promote survival, a phenomenon termed allostasis. However, the chronic activation of energy-dependent allostatic responses results in allostatic load, a dysregulated state that predicts functional decline, accelerates aging, and increases mortality in humans. The energetic cost and cellular basis for the damaging effects of allostatic load have not been defined. Here, by longitudinally profiling three unrelated primary human fibroblast lines across their lifespan, we find that chronic glucocorticoid exposure increases cellular energy expenditure by ∼60%, along with a metabolic shift from glycolysis to mitochondrial oxidative phosphorylation (OxPhos). This state of stress-induced hypermetabolism is linked to mtDNA instability, non-linearly affects age-related cytokines secretion, and accelerates cellular aging based on DNA methylation clocks, telomere shortening rate, and reduced lifespan. Pharmacologically normalizing OxPhos activity while further increasing energy expenditure exacerbates the accelerated aging phenotype, pointing to total energy expenditure as a potential driver of aging dynamics. Together, our findings define bioenergetic and multi-omic recalibrations of stress adaptation, underscoring increased energy expenditure and accelerated cellular aging as interrelated features of cellular allostatic load.
PMID:37423094 | DOI:10.1016/j.psyneuen.2023.106322
Rapid and robust squashed spore/colony PCR of industrially important fungi
Fungal Biol Biotechnol. 2023 Jul 8;10(1):15. doi: 10.1186/s40694-023-00163-0.
ABSTRACT
BACKGROUND: Fungi have been utilized for centuries in medical, agricultural, and industrial applications. Development of systems biology techniques has enabled the design and metabolic engineering of these fungi to produce novel fuels, chemicals, and enzymes from renewable feedstocks. Many genetic tools have been developed for manipulating the genome and creating mutants rapidly. However, screening and confirmation of transformants remain an inefficient step within the design, build, test, and learn cycle in many industrial fungi because extracting fungal genomic DNA is laborious, time-consuming, and involves toxic chemicals.
RESULTS: In this study we developed a rapid and robust technique called "Squash-PCR" to break open the spores and release fungal genomic DNA as a template for PCR. The efficacy of Squash-PCR was investigated in eleven different filamentous fungal strains. Clean PCR products with high yields were achieved in all tested fungi. Spore age and type of DNA polymerase did not affect the efficiency of Squash-PCR. However, spore concentration was found to be the crucial factor for Squash-PCR in Aspergillus niger, with the dilution of starting material often resulting in higher PCR product yield. We then further evaluated the applicability of the squashing procedure for nine different yeast strains. We found that Squash-PCR can be used to improve the quality and yield of colony PCR in comparison to direct colony PCR in the tested yeast strains.
CONCLUSION: The developed technique will enhance the efficiency of screening transformants and accelerate genetic engineering in filamentous fungi and yeast.
PMID:37422681 | DOI:10.1186/s40694-023-00163-0
A computational approach for the identification of key genes and biological pathways of chronic lung diseases: a systems biology approach
BMC Med Genomics. 2023 Jul 8;16(1):159. doi: 10.1186/s12920-023-01596-7.
ABSTRACT
BACKGROUND: Chronic lung diseases are characterized by impaired lung function. Given that many diseases have shared clinical symptoms and pathogenesis, identifying shared pathogenesis can help the design of preventive and therapeutic strategies. This study aimed to evaluate the proteins and pathways of chronic obstructive pulmonary disease (COPD), asthma, idiopathic pulmonary fibrosis (IPF), and mustard lung disease (MLD).
METHODS AND RESULTS: After collecting the data and determining the gene list of each disease, gene expression changes were examined in comparison to healthy individuals. Protein-protein interaction (PPI) and pathway enrichment analysis were used to evaluate genes and shared pathways of the four diseases. There were 22 shared genes, including ACTB, AHSG, ALB, APO, A1, APO C3, FTH1, GAPDH, GC, GSTP1, HP, HSPB1, IGKC, KRT10, KRT9, LCN1, PSMA2, RBP4, 100A8, S100A9, TF, and UBE2N. The major biological pathways in which these genes are involved are inflammatory pathways. Some of these genes activate different pathways in each disease, leading to the induction or inhibition of inflammation.
CONCLUSION: Identification of the genes and shared pathways of diseases can contribute to identifying pathogenesis pathways and designing preventive and therapeutic strategies.
PMID:37422662 | DOI:10.1186/s12920-023-01596-7
Differential contribution of nitrifying prokaryotes to groundwater nitrification
ISME J. 2023 Jul 8. doi: 10.1038/s41396-023-01471-4. Online ahead of print.
ABSTRACT
The ecophysiology of complete ammonia-oxidizing bacteria (CMX) of the genus Nitrospira and their widespread occurrence in groundwater suggests that CMX bacteria have a competitive advantage over ammonia-oxidizing bacteria (AOB) and archaea (AOA) in these environments. However, the specific contribution of their activity to nitrification processes has remained unclear. We aimed to disentangle the contribution of CMX, AOA and AOB to nitrification and to identify the environmental drivers of their niche differentiation at different levels of ammonium and oxygen in oligotrophic carbonate rock aquifers. CMX ammonia monooxygenase sub-unit A (amoA) genes accounted on average for 16 to 75% of the total groundwater amoA genes detected. Nitrification rates were positively correlated to CMX clade A associated phylotypes and AOB affiliated with Nitrosomonas ureae. Short-term incubations amended with the nitrification inhibitors allylthiourea and chlorate suggested that AOB contributed a large fraction to overall ammonia oxidation, while metaproteomics analysis confirmed an active role of CMX in both ammonia and nitrite oxidation. Ecophysiological niche differentiation of CMX clades A and B, AOB and AOA was linked to their requirements for ammonium, oxygen tolerance, and metabolic versatility. Our results demonstrate that despite numerical predominance of CMX, the first step of nitrification in oligotrophic groundwater appears to be primarily governed by AOB. Higher growth yields at lower ammonia turnover rates and energy derived from nitrite oxidation most likely enable CMX to maintain consistently high populations.
PMID:37422599 | DOI:10.1038/s41396-023-01471-4
Zn deficiency disrupts Cu and S homeostasis in Chlamydomonas resulting in over accumulation of Cu and Cysteine
Metallomics. 2023 Jul 8:mfad043. doi: 10.1093/mtomcs/mfad043. Online ahead of print.
ABSTRACT
Growth of Chlamydomonas reinhardtii in zinc (Zn) limited medium leads to disruption of copper (Cu) homeostasis, resulting in up to 40-fold Cu over-accumulation relative to its typical Cu quota. We show that Chlamydomonas controls its Cu quota by balancing Cu import and export, which is disrupted in a Zn deficient cell, thus establishing a mechanistic connection between Cu and Zn homeostasis. Transcriptomics, proteomics and elemental profiling revealed that Zn-limited Chlamydomonas cells up-regulate a subset of genes encoding "first responder" proteins involved in sulfur (S) assimilation and consequently accumulate more intracellular S, which is incorporated into L-cysteine, γ-glutamylcysteine and homocysteine. Most prominently, in the absence of Zn, free L-cysteine is increased ∼80-fold, corresponding to ∼ 2.8×109 molecules/cell. Interestingly, classic S-containing metal binding ligands like glutathione and phytochelatins do not increase. X-ray fluorescence microscopy showed foci of S accumulation in Zn-limited cells that co-localize with Cu, phosphorus and calcium, consistent with Cu-thiol complexes in the acidocalcisome, the site of Cu(I) accumulation. Notably, cells that have been previously starved for Cu do not accumulate S or Cys, causally connecting cysteine synthesis with Cu accumulation. We suggest that cysteine is an in vivo Cu(I) ligand, perhaps ancestral, that buffers cytosolic Cu.
PMID:37422438 | DOI:10.1093/mtomcs/mfad043
Optogenetic control of Cdc48 for dynamic metabolic engineering in yeast
Metab Eng. 2023 Jul 6:S1096-7176(23)00095-2. doi: 10.1016/j.ymben.2023.06.013. Online ahead of print.
ABSTRACT
Dynamic metabolic engineering is a strategy to switch key metabolic pathways in microbial cell factories from biomass generation to accumulation of target products. Here, we demonstrate that optogenetic intervention in the cell cycle of budding yeast can be used to increase production of valuable chemicals, such as the terpenoid β-carotene or the nucleoside analog cordycepin. We achieved optogenetic cell-cycle arrest in the G2/M phase by controlling activity of the ubiquitin-proteasome system hub Cdc48. To analyze the metabolic capacities in the cell cycle arrested yeast strain, we studied their proteomes by timsTOF mass spectrometry. This revealed widespread, but highly distinct abundance changes of metabolic key enzymes. Integration of the proteomics data in protein-constrained metabolic models demonstrated modulation of fluxes directly associated with terpenoid production as well as metabolic subsystems involved in protein biosynthesis, cell wall synthesis, and cofactor biosynthesis. These results demonstrate that optogenetically triggered cell cycle intervention is an option to increase the yields of compounds synthesized in a cellular factory by reallocation of metabolic resources.
PMID:37422133 | DOI:10.1016/j.ymben.2023.06.013
Cytotoxic and apoptotic effects of chemically synthesized silver nanoparticles loaded with recombinant Staphylococcus LukS-PV toxin
J Biotechnol. 2023 Jul 6:S0168-1656(23)00129-3. doi: 10.1016/j.jbiotec.2023.07.001. Online ahead of print.
ABSTRACT
Chronic myeloid leukemia (CML) accounts for approximately 15% of leukemias. LukS-PV, a Panton-Valentine leucocidin (PVL) component, is secreted by Staphylococcus aureus. Silver nanoparticles have increasingly been used for different purposes, most notably for drug delivery and anticancer agents. In this work, the cytotoxicity effect of recombinant LukS-PV protein, chemically synthesized AgNPs, and recombinant LukS-PV protein-loaded silver nanoparticles was investigated on human Chronic myeloid leukemia K562 cells and human normal embryonic kidney HEK293 cells. Cell apoptosis was investigated by staining with Annexin V/propidium iodide. The recombinant LukS-PV protein-loaded silver nanoparticles exhibited dose-dependent cytotoxicity and induced apoptosis in the K562 cells but had little effect on normal HEK293 cells. After 24h of exposure to recombinant LukS-PV protein-loaded silver nanoparticles (IC50 concentration), flow cytometry showed that 31.17% of K562 cells were apoptotic. These results indicate that recombinant LukS-PV protein-loaded silver nanoparticles maybe are a potential chemotherapeutic agent candidate against K562 cells. Hence, silver nanoparticles could be used as drug carriers for toxin release to cancer cells.
PMID:37421980 | DOI:10.1016/j.jbiotec.2023.07.001