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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Comparative Transcriptomics Analyses across Species, Organs, and Developmental Stages Reveal Functionally Constrained lncRNAs

The functionality of long noncoding RNAs (lncRNAs) is disputed. In general, lncRNAs are under weak selective pressures, suggesting that the majority of lncRNAs may be nonfunctional. However, although some surveys showed negligible phenotypic effects upon lncRNA perturbation, key biological roles were demonstrated for individual lncRNAs. Most lncRNAs with proven functions were implicated in gene expression regulation, in pathways related to cellular pluripotency, differentiation, and organ morphogenesis, suggesting that functional lncRNAs may be more abundant in embryonic development, rather than in adult organs. To test this hypothesis, we perform a multidimensional comparative transcriptomics analysis, across five developmental time points (two embryonic stages, newborn, adult, and aged individuals), four organs (brain, kidney, liver, and testes), and three species (mouse, rat, and chicken). We find that, overwhelmingly, lncRNAs are preferentially expressed in adult and aged testes, consistent with the presence of permissive transcription during spermatogenesis. LncRNAs are often differentially expressed among developmental stages and are less abundant in embryos and newborns compared with adult individuals, in agreement with a requirement for tighter expression control and less tolerance for noisy transcription early in development. For differentially expressed lncRNAs, we find that the patterns of expression variation among developmental stages are generally conserved between mouse and rat. Moreover, lncRNAs expressed above noise levels in somatic organs and during development show higher evolutionary conservation, in particular, at their promoter regions. Thus, we show that functionally constrained lncRNA loci are enriched in developing organs, and we suggest that many of these loci may function in an RNA-independent manner.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Bioelectrocatalytic conversion of CO₂ to PHA bioplastics using engineered methylotrophs

The sustainable generation of biodegradable plastics represents an opportunity to capture atmospheric CO 2 while reducing plastic waste accumulation in the environment. This study implements an integrated platform for bioelectrocatalytic CO 2 conversion to medium-chain-length polyhydroxyalkanoates (mcl-PHAs). Immobilizing cobalt phthalocyanine electrocatalysts on a covalent-organic framework in a gas recirculation electrolyzer enabled CO 2 -to-methanol conversion with a carbon conversion efficiency of 98%. Integration of polymer biosynthesis pathways enabled Methylotuvimicrobium alcaliphilum 20Z R to produce ~20% mcl-PHA of the dry cell weight with a CO 2 -to-bioproducts carbon conversion efficiency of 50%. This cell line was adapted to high sodium bicarbonate media, eliminating costly intermediate separation steps while improving economic potential. Transcriptomic analysis revealed sulfate transporters and peptidoglycan biosynthesis as key pathways involved in sodium bicarbonate halotolerance. Altogether, this research presents a foundation for integrating divergent chemical and biological processes into a transformative electrobiomanufacturing platform, addressing the need for alternative pipelines for generating valuable plastics and chemicals.

CO2 utilization↗
DOE OSTI2021

Bioenergy sorghum’s deep roots: A key to sustainable biomass production on annual cropland

Abstract Bioenergy sorghum has high biomass yield potential, drought resilience, good nitrogen use efficiency, and a root system that contributes to the accumulation of soil organic carbon. In this study, field grown bioenergy sorghum root systems were analyzed during the growing season to characterize their depth, biomass, morphology, anatomy, and gene expression profiles. Bioenergy sorghum roots grew continuously during a 155‐day growing season producing ~175 nodal roots, accumulating ~7 Mg of dry biomass per hectare, and reaching >2 m deep in the soil profile. Nodal roots within 20 cm of the stem were 1–5 mm in diameter, whereas roots deeper in soil profiles were enriched in lateral roots with small diameters (~30–500 µm) enabling growth through soil macropores. In older field‐grown plants, roots with intact endodermal, vascular and inner root tissues were surrounded by degraded or aerenchyma‐filled epidermal and cortical cell layers. Transcriptome analysis of nodal, surface, and deep roots identified >2,500 differentially expressed genes involved in root growth, transport, adaptation, defense, and AMF–root interaction. Deep roots (180–240 cm) differentially expressed genes that regulate lateral root growth. Surface roots (0–20 cm) located mid‐row differentially expressed genes involved in nitrate transport, whereas ammonium transport genes were expressed in surface and deep roots and genes involved in phosphate transport were expressed in nodal, surface, and deep roots. Overall, bioenergy sorghum's long growing season enables root systems to grow deeper and accumulate more biomass than annual grain crops such as maize, attributes that could help restore annual cropland soil organic carbon levels and improve soil productivity. Deep roots active in nutrient transport are positioned to take‐up fertilizer leached deep into soil profiles mitigating potential nutrient run‐off. Bioenergy sorghum's large and deep root system is a key to sustainable production of biofuels, biopower, and bioproducts on annual cropland.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Lactiplantibacillus plantarum uses ecologically relevant, exogenous quinones for extracellular electron transfer

Extracellular electron transfer (EET) is a metabolic process that frequently uses quinones to couple intracellular redox reactions with extracellular electron acceptors. The physiological relevance of this metabolism for microorganisms capable of EET but unable to synthesize their own quinones remains to be determined. To address this question, we investigated quinone utilization by Lactiplantibacillus plantarum, a microorganism required for food fermentations, that performs EET and is also a quinone auxotroph. L. plantarum selectively used 1,4-dihydroxy-2-naphthoic acid (DHNA) and more hydrophilic naphthoquinones for EET reduction of insoluble iron (ferrihydrite). However, quinones used for EET also inhibited L. plantarum growth in non-aerated conditions. Transcriptomic analysis showed that DHNA-induced oxidative stress in L. plantarum, but this was alleviated when the electron acceptor, ferric ammonium citrate (FeAC), was included in the growth medium. Although DHNA and FeAC induced L. plantarum EET, this metabolism was still dependent on direct access to environmental electron shuttles. To determine whether quinone-producing food fermentation bacteria could be sources of those electron shuttles, L. plantarum EET was measured after incubation with Lactococcus lactis and Leuconostoc mesenteroides. Quinone-producing L. lactis, but not a quinone-deficient L. lactis ΔmenC mutant, increased L. plantarum ferrihydrite reduction and medium acidification through an EET-dependent mechanism. L. plantarum EET was also stimulated by L. mesenteroides, resulting in greater environmental acidification and transient increases in L. plantarum cell numbers. Our findings show that L. plantarum overcomes the toxic effects of exogenous quinones to use those compounds for EET-conferred, ecological advantages during the early stages of food fermentations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

Enhancing hydrogen‐dependent growth of and carbon dioxide fixation by Clostridium ljungdahlii through nitrate supplementation

Abstract Synthesis gas (syngas) fermentation via the Wood–Ljungdahl pathway is receiving growing attention as a possible platform for the fixation of and renewable production of fuels and chemicals. However, the pathway operates near the thermodynamic limit of life, resulting in minimal adenosine triphosphate (ATP) production and long doubling times. This calls into question the feasibility of producing high‐energy compounds at industrially relevant levels. In this study, we investigated the possibility of co‐utilizing nitrate as an inexpensive additional electron acceptor to enhance ATP production during ‐dependent growth of Clostridium ljungdahlii , Moorella thermoacetica , and Acetobacterium woodii . In contrast to other acetogens tested, growth rate and final biomass titer were improved for C. ljungdahlii growing on a mixture of and when supplemented with nitrate. Transcriptomic analysis, labeling, and an electron balance were used to understand how electron flux was partitioned between and nitrate. We further show that, with nitrate supplementation, the ATP/adenosine diphosphate (ADP) ratio and acetyl‐CoA pools were increased by fivefold and threefold, respectively, suggesting that this strategy could be useful for the production of ATP‐intensive heterologous products from acetyl‐CoA. Finally, we propose a pathway for enhanced ATP production from nitrate and use this as a basis to calculate theoretical yields for a variety of products. This study demonstrates a viable strategy for the decoupling of ATP production from carbon dioxide fixation, which will serve to significantly improve the fixation rate and the production metrics of other chemicals from and in this host.

Emerson, David F.↗
DOE OSTI2022

Flaxseed oil ameliorates aging in d ‐galactose induced rats via altering gut microbiota and mitigating oxidative damage

Abstract BACKGROUND Aging causes decreased antioxidant capacity and chronic inflammation and may even elevate cancer risks. Previous studies reported that flaxseed oil (FO) can alleviate age‐related diseases, including improving alcoholic liver disease, atherosclerosis and diabetes. However, whether the intestinal microbiota accountable for this alleviation is still unknown. This study aims to study the antioxidant effects of FO in an aging rat model and the underlying mechanism between the intestinal microbiota and aging. RESULTS Our results presented that serum and liver antioxidant capacities in FO group were up‐regulated, and liver inflammation in FO group was reduced. The 16S rDNA sequencing showed that FO regulated the microbial community, including up‐regulation of four families of Lactobacillus and six families of Clostridium. In addition, FO had also adjusted the relative abundance of several genera such as Ruminococcaceae_UCG‐005 and Prevotella_9 , which may be the key bacteria associated with the aging process. Colonic transcriptome analysis showed that there were 1679 differentially expressed genes (DEGs) in the Model group and the FO group (134 up‐regulated and 1545 down‐regulated). Gene set enrichment analysis (GSEA) revealed FO down‐regulates the expression of the upstream genes Ptprc , Lck , Zap70 , Lat and Lcp2 in the T cell receptor signaling pathway. CONCLUSION In conclusion, FO improved antioxidant capacity and reduced intestinal microbial disturbances caused by aging damage, indicating that dietary FO has the potential to fight aging damage. This study provides a more comprehensive view of dietary intervention to improve aging. © 2022 Society of Chemical Industry.

Sun, Xiaoyan↗
DOE OSTI2020

Cytochrome P450s CYP380C6 and CYP380C9 in green peach aphid facilitate its adaptation to indole glucosinolate‐mediated plant defense

Abstract BACKGROUND Overexpressing CIRCADIAN CLOCK ASSOCIATED1 in Arabidopsis thaliana ( CCA1‐ox ) increases indole glucosinolate production and resistance to green peach aphid ( Myzus persicae ). Little is known of how aphids respond to this group of plant defense compounds or of the underlying molecular mechanism. Results Aphids reared on CCA1‐ox for over 40 generations (namely the CCA population) became less susceptible to CCA1‐ox than aphids maintained on the wild‐type Col‐0 (namely the COL population). This elevated tolerance was transgenerational as it remained for at least eight generations after the CCA population was transferred to Col‐0. Intriguingly, transcriptome analysis indicated that all differential cytochrome P450 monooxygenase genes ( MpCYPs ), primarily MpCYP4 s, MpCYP380s and MpCYP6 s, were more highly expressed in the CCA population. Application of a P450 inhibitor to the CCA population resulted in decreased aphid reproduction on CCA1‐ox , which was not observed if aphids were reared on Col‐0. When indole glucosinolate biosynthesis in CCA1‐ox was blocked using virus‐induced gene silencing, the effect of the P450 inhibitor on the CCA population was attenuated, affirming the essential role played by MpCYPs in counteracting the defense mechanism in CCA1‐ox that is low or absent in Col‐0. Furthermore, we used host‐induced gene silencing to identify MpCYP380C6 and MpCYP380C9 that specifically facilitated the CCA population to cope with CCA1 ‐mediated plant defense. Expression profiles revealed their possible contribution to the transgenerational tolerance observed in aphids. Conclusion MpCYP380C6 and MpCYP380C9 in aphids play a crucial role in mitigating indole glucosinolate‐mediated plant defense, and this effect is transgenerational.

Ji, Rui↗
DOE OSTI2019

Transcriptome Guided Drug Combination Suppresses Proliferation of Breast Cancer Cells

One of actively developing trends in modern pharmacology is the use of the transcriptome analysis for drug repositioning. We have previously detected two molecular markers of relapses in patients with malignant breast tumors: ELOVL5 and IGFBP6. Poor prognosis is associated with low expression of these markers. Here we analyze the effects of simvastatin and a new potential proteasome inhibitor K7174 inducing expression of IGFBP6 and EVOVL5 on the proliferation of breast cancer cells MDA-MB-231 and DU4475. Compound K7174 potentiates the inhibitory effect of simvastatin on the proliferation of DU4475 cells characterized by low expression of ELOVL5-IGFBP6 pair, but not on the proliferation of MDA-MB-231 cells with high expression of these markers.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

Genetic disruption of tubulin acetyltransferase, αTAT1, inhibits proliferation and invasion of colon cancer cells through decreases in Wnt1/β-catenin signaling

Microtubules are required for diverse cellular processes, and abnormal regulation of microtubule dynamics is closely associated with severe diseases including malignant tumors. In this study, we report that α-tubulin N-acetyltransferase (αTAT1), a regulator of α-tubulin acetylation, is required for colon cancer proliferation and invasion via regulation of Wnt1 and its downstream genes expression. Public transcriptome analysis showed that expression of ATAT1 is specifically upregulated in colon cancer tissue. A knockout (KO) of ATAT1 in the HCT116 colon cancer cell line, using the CRISPR/Cas9 system showed profound inhibition of proliferative and invasive activities of these cancer cells. Overexpression of αTAT1 or the acetyl-mimic K40Q α-tubulin mutant in αTAT1 KO cells restored the invasiveness, indicating that microtubule acetylation induced by αTAT1 is critical for HCT116 cell invasion. Analysis of colon cancer-related gene expression in αTAT1 KO cells revealed that the loss of αTAT1 decreased the expression of WNT1. Mechanistically, abrogation of tubulin acetylation by αTAT1 knockout inhibited localization of β-catenin to the plasma membrane and nucleus, thereby resulting in the downregulation of Wnt1 and of its downstream genes including CCND1, MMP-2, and MMP-9. These results suggest that αTAT1-mediated Wnt1 expression via microtubule acetylation is important for colon cancer progression. - Highlights: • Ablation of αTAT1 inhibits HCT116 colon cancer cell invasion. • αTAT1/acetylated microtubules regulate expression of Wnt1/β-catenin target genes. • Acetylated microtubules regulate cellular localization of β-catenin. • Loss of αTAT1 prevents Wnt1 from inducing β-catenin-dependent and -independent pathways.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

A-674563 increases chondrocyte marker expression in cultured chondrocytes by inhibiting Sox9 degradation

Highlights: • We established a high-throughput screening system for induction of chondrocytic characters. • We screened 5822 compounds and found that A-674563 enhanced transcription of chondrocyte markers. • A-674563 inhibited the degradation of Sox9 protein. • A-674563 increased expression of ubiquitin-specific peptidase 29, which is known to induce deubiquitination. The implantation of autologous chondrocytes is a therapeutic treatment for articular cartilage damage. However, the benefits are limited due to the expansion of chondrocytes in monolayer culture, which causes loss of chondrocytic characters. Therefore, culture conditions that enhance chondrocytic characters are needed. We screened 5822 compounds and found that A-674563 enhanced the transcription of several chondrocyte marker genes, including Col2a1, Acan and Col11a2, in mouse primary chondrocytes. Experiments using cycloheximide, MG132 and bafilomycin A1 have revealed that Sox9 is degraded through the ubiquitin-proteasome pathway and that A-674563 inhibits this degradation, resulting in larger amount of Sox9 protein. RNA sequencing transcriptome analysis showed that A-674563 increases the expression of the gene that encodes ubiquitin-specific peptidase 29, which is known to induce the deubiquitination of proteins. Although the precise mechanism remains to be determined, our findings indicated that A-674563 could contribute to culture conditions that expand chondrocytes without losing chondrocytic characters.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Spindle pole body component 25 homolog expressed by ECM stiffening is required for lung cancer cell proliferation

Highlights: • Matrix stiffness regulates the expression of genes involved in cell proliferation. • SPC25 is identified as hazard gene induced by matrix stiffness. • SPC25 is involved in cancer cell proliferation under stiff matrix conditions. • Depletion of SPC25 induces G2/M arrest via chromosome misalignment in metaphase. Accumulating evidence has shown that matrix stiffening in cancer tissue by the deposition of extracellular matrix (ECM) is closely related with severe tumor progression. However, much less is known about the genes affected by matrix stiffness and its signaling for cancer progression. In the current research, we investigated the differential gene expression of a non-small lung adenocarcinoma cell line, H1299, cultured under the conditions of soft (∼0.5 kPa) and stiff (∼40 kPa) matrices, mimicking the mechanical environments of normal and cancerous tissues, respectively. For integrated transcriptome analysis, the genes identified by ECM stiffening were compared with 8248 genes retrieved from The Cancer Genome Atlas Lung Adenocarcinoma (TCGA). In stiff matrix, 29 genes were significantly upregulated, while 75 genes were downregulated. The screening of hazard ratios for these genes using the Kaplan-Meier Plotter identified 8 genes most closely associated with cancer progression under the condition of matrix stiffening. Among these genes, spindle pole body component 25 homolog (SPC25) was one of the most up-regulated genes in stiff matrix and tumor tissue. Knockdown of SPC25 in H1299 cells using shRNA significantly inhibited cell proliferation with downregulation of the expression of checkpoint protein, Cyclin B1, under the condition of stiff matrix whereas the proliferation rate in soft matrix was not affected by SPC25 silencing. Thus, our findings provide novel key molecules for studying the relationship of extracellular matrix stiffening and cancer progression.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Ectopic expression of the TAL effector AvrXa7 in Xanthomonas citri subsp. citri hinders citrus canker symptom formation by modulating transcriptional profile of citrus genes

Highlights: • Xanthomonas TAL effector AvrXa7 showed a suppression effect on citrus canker. • The AvrXa7 modulated the transcription profile of citrus genes. • The AvrXa7 targets CsLOX2-1 to promote citrus defense reaction. Xanthomonas citri subsp. citri (Xcc) is the causal agent of citrus canker, a serious bacterial disease that affects citrus trees worldwide. The ectopic expression of TAL effector AvrXa7 in Xcc suppressed canker development. The Xcc strain expressing avrXa7 induced a yellow symptom around the inoculation site. Transcriptome analysis revealed 315 differentially expressed genes, which were categorized into several functional groups. The more interesting genes were those involved in the biosynthesis of terpene and ethylene. In particular, the linoleate 13 S-lipoxygenase gene CsLOX2-1 was found to possess the AvrXa7 binding sequence in the promoter region. The recognition of AvrXa7 to the CsLOX2-1 promoter was subsequently confirmed by yeast one-hybrid and electrophoretic mobility shift experiments. This demonstrated that the TALE effector AvrXa7 promotes CsLOX2-1 expression by directly binding to the promoter sequence. Our findings contribute a valuable clue to identifying the potential genes that can be used to prevent citrus canker.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Direct and rapid identification of T315I-Mutated BCR-ABL expressing leukemic cells using infrared microspectroscopy

Highlights: • BCR-ABL T315I mutation can be detected in single leukemic cells using infrared microspectroscopy. • The specificity of this spectral signature is demonstrated using Dox-inducible T315I-mutated BCR-ABL expressing cell lines. • Leukemic cells expressing T315I-mutated BCR-ABL exhibit a distinct transcriptome signature. • This technology could be applied to rapid detection of leukemic cells expressing T315I and to drug screening strategies. Despite the major success obtained by the use of tyrosine kinase inhibitors (TKI) in chronic myeloid leukemia (CML), resistances to therapies occur due to mutations in the ABL-kinase domain of the BCR-ABL oncogene. Amongst these mutations, the “gatekeeper” T315I is a major concern as it renders leukemic cells resistant to all licenced TKI except Ponatinib. We report here that Fourier transform infrared (FTIR) microspectroscopy is a powerful methodology allowing rapid and direct identification of a spectral signature in single cells expressing T315I-mutated BCR-ABL. The specificity of this spectral signature is confirmed using a Dox-inducible T315I-mutated BCR-ABL-expressing human UT-7 cells as well as in murine embryonic stem cells. Transcriptome analysis of UT-7 cells expressing BCR-ABL as compared to BCR-ABL T315I clearly identified a molecular signature which could be at the origin of the generation of metabolic changes giving rise to the spectral signature. Thus, these results suggest that this new methodology can be applied to the identification of leukemic cells harbouring the T315I mutation at the single cell level and could represent a novel early detection tool of mutant clones. It could also be applied to drug screening strategies to target T315I-mutated leukemic cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Ploidy-dependent change in cyclin D2 expression and sensitization to cdk4/6 inhibition in human somatic haploid cells

Near-haploidy is observed in certain cancer types, but ploidy-dependent alterations in gene regulation in the haploid state remain elusive. Here, by comparative transcriptome analysis between human isogenic haploid and diploid cell lines, we found lowering of cyclin D2 level in haploids. Acute genome duplication in haploids restored cyclin D2 expression to diploid level, indicating that the regulation of cyclin D2 expression is directly linked to ploidy. Downstream pathways of cyclin D2, such as Rb phosphorylation and p27 sequestration remained intact in haploids, suggesting that they adapt to lowered cyclin D level. Interestingly, however, haploid cells were more susceptible to cdk4/6 inhibition compared to diploids. Our finding indicates feasibility of selective growth suppression of haploid cells based on ploidy-linked gene regulation.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

SmpB down-regulates proton-motive force for the persister tolerance to aminoglycosides in Aeromonas veronii

Highlights: • The smpB deletion exhibited a higher susceptibility to aminoglycosides in A. veronii. • The expression level of SmpB was enhanced by gentamicin challenge. • The effect of SmpB on persistence formation was eliminated by PMF inhibition. • The smpB deletion downregulated proton-motive force-related metabolic genes. Bacterial persisters comprise a small fraction of phenotypically heterogeneous variants with transient capability for survival when exposed to high concentrations of antibiotic. In aquatic pathogenic bacteria Aeromonas veronii, Small Protein B (SmpB), the core factor of trans-translation system, was identified as a new persistence-related gene. The SmpB deletion exhibited a higher susceptibility and lower persister cell formation under aminoglycosides antibiotics pressure compared with wild type. The transcriptional and translational activities of smpB gene were significantly enhanced by the gentamicin challenge in exponential phase, but not changed in stationary phase. The transcriptomic analysis revealed that the smpB deletion stimulated the production of proton-motive force (PMF). The cell survival induced by carbonyl cyanide m-chlorophenyl hydrazone (CCCP) further verified that SmpB variation affected the quantities of PMF. Taken together, these results uncovered a novel mechanism of persister formation mediated by SmpB under aminoglycosides treatments.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Short-term administration of iso-α-acids increases transthyretin transcription in the hippocampus

Cognitive decline and dementia are currently recognized as major problems in the aging population; however, there is still no promising treatment for these conditions. Previously, our group reported that iso-α-acids (IAAs), which are hop-derived bitter components present in beer, prevent inflammation and cognitive impairment in an Alzheimer's disease model mice (5xFAD mice) and yield significant reduction in amyloid β (Αβ) in the brain. However, data on the molecular mechanisms underlying these physiological effects of IAAs remain limited. Here, we used transcriptome analysis and found that oral administration of IAAs to 5xFAD mice for 7 days induces a 58.9-fold increase in the expression of transthyretin (TTR; Ttr) in the hippocampus compared with controls. In addition, real-time quantitative PCR showed that oral administration of IAAs significantly increased Ttr transcription in the hippocampi of wild type C57BL/6J mice but not in the cerebral cortex. TTR is an Αβ protein scavenger; thus, an increase in its expression could prevent amyloid aggregate formation. These results indicate that IAAs reduce Αβ in the brain by elevating TTR levels.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Lytic polysaccharide monooxygenase synergized with lignin-degrading enzymes for efficient lignin degradation

Even though the discovery of lytic polysaccharide monooxygenases (LPMOs) has fundamentally shifted our understanding of biomass degradation, most of the current studies focused on their roles in carbohydrate oxidation. However, no study demonstrated if LPMO could directly participate to the process of lignin degradation in lignin-degrading microbes. This study showed that LPMO could synergize with lignin-degrading enzymes for efficient lignin degradation in white-rot fungi. The transcriptomics analysis of fungi Irpex lacteus and Dichomitus squalens during their lignocellulosic biomass degradation processes surprisingly highlighted that LPMOs co-regulated with lignin-degrading enzymes, indicating their more versatile roles in the redox network. Biochemical analysis further confirmed that the purified LPMO from I. lacteus CD2 could use diverse electron donors to produce H 2 O 2 , drive Fenton reaction, and synergize with manganese peroxidase for lignin oxidation. The results thus indicated that LPMO might uniquely leverage the redox network toward dynamic and efficient degradation of different cell wall components.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Elucidating biodegradation of dimethyl terephthalate by two Rhodococcus strains for its valorization applications

Dimethyl terephthalate (DMT) serves as the precursor in the production of polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate. The widespread use of DMT in the polymer industry and its ubiquitous existence in end products raise alarms about its potential harm to humans and animals. DMT can enter the environment through the degradation of polymers and their end products, and cause endocrine disruption, oxidative stress, and an elevated risk of cancer. In recent years, DMT has also gained renewed interest in its potential for plastic recycling and upcycling. In this study, we identified two strains of Rhodococcus that possess DMT-degrading capabilities and utilized transcriptomic analysis and gene knockout to elucidate the mechanisms of DMT degradation. R. opacus PD630 and R. jostii RPET were found to convert up to 1 g/L DMT into mono-methyl terephthalate (MMT). A putative DMTase (RS34275) was identified for this conversion. R. jostii RPET also demonstrates the ability to convert DMT into MMT and to utilize MMT for its cellular growth via the terephthalate pathway. A putative MMTase (RS21885) as the sole enzyme was identified for the conversion of MMT into terephthalate in the RPET strain. In addition, we successfully produced lycopene and lipids from an engineered RPET strain using DMT as a substrate. Our findings will facilitate future DMT bioremediation and bio-upcycling of DMT-associated plastics, enabling the production of value-added products.

Biodegradation↗