Reductase Gene Research Articles

Prevalence of molecular markers of sulfadoxine-pyrimethamine resistance in Plasmodium falciparum isolates from West Africa during 2012–2022

Sulfadoxine-pyrimethamine (SP) is a key drug recommended by the World Health Organization for the chemoprevention of malaria. However, the strategy is affected by the parasite resistance to SP. This study evaluated Plasmodium falciparum dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes, associated with SP resistance, from 508 P. falciparum isolates imported from West African countries to Henan Province, China, during 2012–2022. High mutant prevalence of the genes Pfdhfr (94.7%) and Pfdhps (96.8%) was observed. The mutants Pfdhfr N51I, C59R, S108N, and Pfdhps A437G were at high frequency in all countries analyzed. The overall prevalence of the mutant Pfdhps K540E was low (3.4%), but with a high frequency in Liberia (24.3%). The frequency of mutants Pfdhps I431V, A581G, and A613S was 11.7%, 9.8%, and 16.2%, respectively, all of which had the highest mutant prevalence in Nigeria. The mutant Pfdhps A581G and A613S were identified in the absence of K540E. The partially resistant haplotype (I51R59N108 - G437) was the most common (72.6%), and the fully resistant haplotype (I51R59N108 - G437E540) had a low prevalence of 3.4% and mainly occurred in Liberia. No super resistant haplotype was identified. The mutant Pfdhps I431V and the octuple mutant haplotype I51R59N108 - V431A436G437G581S613 deserve more attention. In areas of high SP resistance, the intervention still reduces low birthweight and maternal anaemia. SP should continue to be used in areas of high SP resistance until more effective alternatives for malaria chemoprevention are found. It is important to continuously monitor the molecular markers associated with SP resistance to better implement intermittent preventive treatment policies in pregnancy (IPTp) and infants (IPTi).

Overlapping Transcriptome Alterations Reveal the Mechanism of Interaction between Selenium and Zinc and Their Common Effect on Essential Nutrient Metabolism in Mung Bean (Vigna radiata L.).

Selenium (Se) and zinc (Zn) deficiencies have become serious global food security and public health problems. Biofortification through foliar fertilizer is a nonspecific, low-tech, and cost-effective strategy. Se and Zn have overlapping physiological roles and interacting relationships in plants. Mung bean is superior for Se enrichment and an excellent Zn carrier. However, the molecular mechanism underlying the interaction between Se and Zn in the mung bean remains unclear. Herein, Se and Zn accumulation, antioxidant activities, physiological determination, and transcriptomic analysis were performed under both Se and Zn treatments. Common essential roles of Se and Zn in mung bean were reflected by the comprehensively altered ten physiological indexes under both Se2 (24 g·ha-1) and Zn1 (1.2 kg·ha-1) treatments. Overlapping transcriptome changes and common DEGs in two compared groups revealed that the upregulated expression of sulfate transporters (SULTRs), phosphate transporters (PHTs), and Zinc-regulated/Iron-regulated-like protein (ZIP) family genes under Se and Zn treatments directly promoted both Se and Zn intakes. Furthermore, the altered Se/Sulfur, nitrogen, and carbohydrate metabolisms are closely interlinked with the uptake and assimilation of Se and Zn via the 20 key genes that we filtered through the protein-protein interaction (PPI) network analysis. Further analysis indicated that l-methionine γ-lyase (E 4.4.1.11) genes may play an important role in the transamination of selenomethionine and its derivatives; glutamine synthetase (GS), nitrate reductase (NR), and starch synthase (SS) genes may regulate the nitrogen assimilation and carbohydrate metabolism, which provide more carriers for Se and Zn; glutathione peroxidase (GPx), glutamate-cysteine ligase catalytic subunit (GCLC), and serine acetyltransferase (SAT) genes may accelerate the GSH-GSSH cycle and promote Se and Zn storages. This study provides new molecular insights into the comprehensive improvement of the nutritional quality of mung beans in Se and Zn biofortification productions.

Multiple variables influence the finely calibrated antioxidant defenses of Clostridioides difficile.

The obligate anaerobe Clostridioides difficile encodes multiple reductases to detoxify molecular oxygen and reactive oxygen species. Caulat and colleagues have characterized the activity and regulation of four such reductases (L. C. Caulat, A. Lotoux, M. C. Martins, N. Kint, et al., mBio 15:e01591-24, 2024, https://doi.org/10.1128/mbio.01591-24). Each proved critical for clostridial survival in a different range of oxygen concentrations; together, they ameliorate a broad range of oxidative stress levels. Moreover, two previously uncharacterized regulators were found to control reductase gene expression in response to oxidative stress. The genetic repressor Rex and the reductase FdpF are both sensitive to the NAP+:NADH ratio, which is affected by a cell's metabolic state as well as redox activity. While oxygen is known to influence the expression of metabolism genes in C. difficile, the mechanisms for cross-talk between the pathways that respond to oxidative and metabolic stress are not well known. The NADH dependence of Rex and FdpF may represent a newly mapped junction between these pathways.

Combined Transcriptome and Metabolome Analyses Provide New Insights into the Changes in the Flesh Color of Anthocyanins in Strawberry (Fragaria × ananassa (Weston) Duchesne ex Rozier)

Background: Strawberries are bright in color, sweet and sour in taste, and rich in nutrients and flavonoid compounds such as anthocyanins and proanthocyanidins. The synthesis and accumulation of anthocyanins are the decisive factors that make strawberries appear bright red. From the perspective of plant breeding, a change in flesh color is an important goal. Methods: In this study, two strawberry plants with different flesh colors were selected, and transcriptome and metabolome analyses were performed during the color change period (S1) and ripening period (S2). Results: RNA-seq revealed a total of 13,341 differentially expressed genes (DEGs) between and within materials, which were clustered into 5 clusters. A total of 695 metabolites were detected via metabolome analysis, and 243 differentially regulated metabolites (DRMs) were identified. The anthocyanin biosynthesis, starch and sucrose metabolism and glycolysis/gluconeogenesis pathways were determined to be important regulatory pathways for changes in strawberry flesh color through a joint analysis of RNA-seq data and the metabolome. The leucoanthocyanidin reductase (LAR) and chalcone synthase (CHS) gene is a key gene related to anthocyanins, cinnamic acid, and phenylalanine. In addition, through joint RNA-seq and metabolome analyses combined with weighted gene co-expression network analysis (WGCNA), we identified 9 candidate genes related to strawberry flesh color. Conclusions: Our research findings have laid the groundwork for a more comprehensive understanding of the molecular mechanisms governing the color transformation in strawberry flesh. Additionally, we have identified novel genetic resources that can be instrumental in advancing research related to strawberry color change.

Further Evidence of Anthropogenic Impact: High Levels of Multiple-Antimicrobial-Resistant Bacteria Found in Neritic-Stage Sea Turtles

Background/Objectives: Marine turtles are globally threatened and face daily anthropogenic threats, including pollution. Water pollution from emerging contaminants such as antimicrobials is a major and current environmental concern. Methods: This study investigated the phenotypic antimicrobial resistance and heavy metal resistance genes of 47 Vibrio isolates from different stages of sea turtles (oceanic stage vs neritic stage) from the Taiwanese coast. Results: The results show that a high proportion (48.9%; 23/47) of the Vibrio species isolated from sea turtles in our study had a multiple antimicrobial resistance (MAR) pattern. It was found that Vibrio spp. isolates with a MAR pattern and those with a MAR index value greater than 0.2 were both more likely to be observed in neritic-stage sea turtles. Furthermore, isolates from neritic-stage sea turtles exhibited greater resistance to the majority of antimicrobials tested (with the exception of beta-lactams and macrolides) than isolates from the oceanic-stage groups. Isolates from neritic sea turtles were found to be more resistant to nitrofurans and aminoglycosides than isolates from oceanic sea turtles. Furthermore, isolates with a MAR pattern (p = 0.010) and those with a MAR index value greater than 0.2 (p = 0.027) were both found to be significantly positively associated with the mercury reductase (merA) gene. Conclusions: The findings of our study indicate that co-selection of heavy metals and antimicrobial resistance may occur in aquatic bacteria in the coastal foraging habitats of sea turtles in Taiwan.

Biofilm Formation on Excavation Damaged Zone Fractures in Deep Neogene Sedimentary Rock.

Deep underground galleries are used to access the deep biosphere in addition to mining and other engineering applications, such as geological disposal of radioactive waste. Fracture networks developed in the excavation damaged zone (EDZ) are concerned with accelerating mass transport, where microbial colonization might be possible due to the availability of space and nutrients. In this study, microbial biofilms at EDZ fractures were investigated by drilling from a 350-m-deep gallery and subsequent borehole logging at the Horonobe Underground Research Laboratory (URL). By using microscopic and spectroscopic techniques, the dense colonization of microbial cells was demonstrated at the surfaces of the EDZ fractures with high hydraulic conductivity. 16S rRNA gene sequence analysis revealed the dominance of gammaproteobacterial lineages, the cultivated members of which are aerobic methanotrophs. The near-complete genomes from Horonobe groundwater, affiliated with the methanotrophic lineages, were fully equipped with genes involved in aerobic methanotrophy. Although the mediation of aerobic methanotrophy remains to be demonstrated, microbial O2 production was supported by the presence of genes in the near-complete genomes, such as catalase and superoxide dismutase that produce O2 from reactive oxygen species and a nitric oxide reductase gene with the substitutions of amino acids in motifs. It is concluded that the EDZ fractures provide energetically favorable subsurface habitats for microorganisms.

Arsenic Stress Mitigation Using a Novel Plant Growth-Promoting Bacterial Strain Bacillus mycoides NR5 in Spinach Plant (Spinacia oleracea L.).

Present study aimed to identify arsenic (As)-resistant bacterial strains that can be used to mitigate arsenic stress. A bacterium Bacillus mycoides NR5 having As tolerance limit of 1100 mg L-1 was isolated from Nag River, Maharashtra, India. It was also equipped with plant growth-promoting (PGP) attributes like phosphate solubilization, siderophores, ammonia, and nitrate reduction, with added antibiotic tolerance. Furthermore, scanning electron microscopy (SEM) and transmission electron micrograph (TEM) suggested biosorption as possible mechanisms of arsenic tolerance. A strong peak in FTIR spectra at 3379.0 corresponding to amine in As-treated NR5 also indicated metal interaction with cell surface protein. Amplification of arsenic reductase gene in NR5 further suggested intracellular transformation of As speciation. Moreover, As tolerance capability of NR5 was shown in spinach plants in which the bacterium effectively mitigated 25 ppm As by producing defense-related proline molecules. Evidence from SEM, TEM, and FTIR, concluded biosorption possibly the primary mechanism of As tolerance in NR5 along with the transformation of arsenic. B. mycoides NR5 with PGP attributes, high As tolerance, and antibiotic resistance mediated enhanced As tolerance in spinach plants advocated that the strain can be a better choice for As bioremediation in contaminated agricultural soil and water.

Integrated Analysis of Transcriptome and Metabolome Provides Insights into Flavonoid Biosynthesis of Blueberry Leaves in Response to Drought Stress.

Blueberries (Vaccinium spp.) are extremely sensitive to drought stress. Flavonoids are crucial secondary metabolites that possess the ability to withstand drought stress. Therefore, improving the drought resistance of blueberries by increasing the flavonoid content is crucial for the development of the blueberry industry. To explore the underlying molecular mechanism of blueberry in adaptation to drought stress, we performed an integrated analysis of the metabolome and transcriptome of blueberry leaves under drought stress. We found that the most enriched drought-responsive genes are mainly involved in flavonoid biosynthesis and plant hormone signal transduction pathways based on transcriptome data and the main drought-responsive metabolites come from the flavonoid class based on metabolome data. The UDP-glucose flavonoid 3-O-glucosyl transferase (UFGT), flavonol synthase (FLS), and anthocyanidin reductase (ANR-2) genes may be the key genes for the accumulation of anthocyanins, flavonols, and flavans in response to drought stress in blueberry leaves, respectively. Delphinidin 3-glucoside and delphinidin-3-O-glucoside chloride may be the most important drought-responsive flavonoid metabolites. VcMYB1, VcMYBPA1, MYBPA1.2, and MYBPA2.1 might be responsible for drought-induced flavonoid biosynthesis and VcMYB14, MYB14, MYB102, and MYB108 may be responsible for blueberry leaf drought tolerance. ABA responsive elements binding factor (ABF) genes, MYB genes, bHLH genes, and flavonoid biosynthetic genes might form a regulatory network to regulate drought-induced accumulation of flavonoid metabolites in blueberry leaves. Our study provides a useful reference for breeding drought-resistant blueberry varieties.

Evolution of Pfdhps and Pfdhfr mutations before and after adopting seasonal malaria chemoprevention in Nanoro, Burkina Faso

Seasonal Malaria Chemoprevention consisting of monthly administration of amodiaquine/sulfadoxine-pyrimethamine to children aged 3–59 months during the transmission season could promote SP-resistance. Mutations in dihydrofolate reductase (Pfdhfr) and dihydropteroate synthase (Pfdhps) genes were assessed before and after SMC adoption in Burkina Faso. A total of 769 dried blood spots were selected from studies conducted in Nanoro, Burkina Faso, between 2010 and 2020. Of those, 299 were pre-SMC (2010–2012) and 470 were post-SMC-samples. Pfdhps and Pfdhfr genes were PCR-amplified and sequenced. A systematic review/meta-analysis of published studies conducted in Burkina Faso (2009–2023) was additionally performed. In Nanoro, the prevalence of Pfdhfr triple mutations (CIRNI) rose from 43.6% pre-SMC to 89.4% post-SMC (p < 0.0001). There was no mutation in Pfdhfr 164 and Pfdhps 540; Pfdhps A437G mutation increased from 63.9% (2010–2012) to 84.7% (2020) (p < 0.0001). The VAGKGS haplotype was 2.8% (2020). Pfdhfr/Pfdhps quintuple mutant IRN-436A437G rose from 18.6% (2010–2012) to 58.3% (2020) (p < 0.0001). Meta-analysis results from Burkina Faso showed an increase in mutations at Pfdhfr N51I, C59R, S108N, and Pfdhps A437G after SMC adoption. Post-SMC, the pyrimethamine-resistance marker prevalence increased, while the sulfadoxine-resistance marker prevalence remained stable. Detection of emerging PfdhpsVAGKGS haplotypes in 2020 underscores the importance of continuous SP-resistance monitoring.

Functional characterization of chalcone reductase gene CHR3 through RNAi

In this experiment, the soybean genome "Jilin 30" was used as a template to clone the target gene CHR3 using specific primers. The sense fragment, antisense fragment, and intron of the target gene were ligated into pCAMBIA3300 through double enzyme digestion to form a stem loop structure. We then transferred the constructed RNAi vector pCAMBIA3301-CHR3 RNAi into the recipient soybean genome via Agrobacterium mediated method, specifically reducing the expression of the target gene CHR3. By genetic transformation, positive plants were obtained, and molecular biology methods such as Southern blotting, real-time quantitative PCR, isoliquiritigenin analysis, and identification of resistance to Phytophthora root rot were used to detect the expression level of the CHR3 gene in the positive plants and study its function.The RNAi expression vector pCAMBIA3300-CHR3-RNAi was successfully constructed using the sense and antisense fragments of 428 bp CHR3 gene and an intron of 110 bp was inserted to form the stem-loop structure of the RNAi vector. PCR was used to detect 6 lines of the T1 generation and 15 lines of the T2 generation. The results of Southern analysis confirmed the integration of CHR3 and marker genes into the soybean genome. The expression CHR3 gene in the T1 genotypes decreased by 13.1 to 58.3%; the expression in the root decreased by 0.9 to 47.4%; the expression in the leaf decreased by 20 to 44.2%; and the expression in the stem decreased by 7.6 to 23%. The content of isoliquiritigenin decreased by 26.7% as transgenic shoots had a lower content of isoliquiritigenin and reduced resistance to Phytophthora sojae. Bangladesh J. Bot. 53(3): 627-633, 2024 (September) Special

Enhancing fatty acid and omega-3 production in Schizochytrium sp. using developed safe-harboring expression system

BackgroundSchizochytrium, a group of eukaryotic marine protists, is an oleaginous strain, making it a highly promising candidate for the production of lipid-derived products such as biofuels and omega-3 fatty acids. However, the insufficient advancement of genetic engineering tools has hindered further advancements. Therefore, the development and application of genetic engineering tools for lipid enhancement are crucial for industrial production.ResultsTransgene expression in Schizochytrium often encounters challenges such as instability due to positional effects. To overcome this, we developed a safe-harbor transgene expression system. Initially, the sfGFP gene was integrated randomly, and high-expressing transformants were identified using fluorescence-activated cell sorting. Notably, HRsite 2, located approximately 3.2 kb upstream of cytochrome c, demonstrated enhanced sfGFP expression and homologous recombination efficiency. We then introduced the 3-ketoacyl-ACP reductase (KR) gene at HRsite 2, resulting in improved lipid and docosahexaenoic acid (DHA) production. Transformants with KR at HRsite 2 exhibited stable growth, increased glucose utilization, and a higher lipid content compared to those with randomly integrated transgenes. Notably, these transformants showed a 25% increase in DHA content compared to the wild-type strain.ConclusionThis study successfully established a robust homologous recombination system in Schizochytrium sp. by identifying a reliable safe harbor site for gene integration. The targeted expression of the KR gene at this site not only enhanced DHA production but also maintained growth and glucose consumption rates, validating the efficacy of the safe-harbor approach. This advancement in synthetic biology and metabolic engineering paves the way for more efficient biotechnological applications in Schizochytrium sp.

Diversity and transcription of genes involved in respiratory As(V) reduction and As(III) methylation in Japanese paddy soils

BackgroundArsenic (As) metabolism by soil microorganisms has an impact on As geochemical cycling in paddy soils, which in turn affects As uptake in rice. However, little is known about the key microorganisms involved in this process in Japanese paddy soil.ResultsTotal RNA was extracted from Japanese paddy soils with different levels of dissolved As under flooded conditions, and the transcription of As metabolic genes (arrA, ttrA and arsM) was analyzed via a metatranscriptomic approach. The results showed that ttrA was the predominant respiratory arsenate reductase gene transcribed in these soils rather than arrA, suggesting that ttrA contributes to the reductive dissolution of As. The predominant taxa expressing ttrA differed among soils but were mostly associated with genera known for their iron- and/or sulfate-reduction activity. In addition, a wide variety of microorganisms expressed and upregulated arsM approximately 5.0- to 13.2-fold at 9 d compared with 3 d of incubation under flooded conditions in flasks.ConclusionsOur results support the involvement of microbial activity in the geochemical cycling of As in Japanese paddy soils and suggest that ttrA may be one of the key genes involved in the formation of arsenite, an inorganic species taken up by rice.

Metabolic engineering of Halomonas bluephagenesis for the production of ethylene glycol and glycolate from xylose

Halophilic Halomonas bluephagenesis, a natural producer of poly-3-hydroxybutyrate (PHB), was metabolically engineered to synthesize ethylene glycol and glycolate from xylose. Xylose utilization was achieved by overexpressing either the xylonate pathway or the ribulose-1-phosphate pathway. The key genes encoding for xylonate dehydratase and 2-keto-3-deoxy-xylonate aldolase in the xylonate pathway were screened. With further overexpressing aldehyde reductase gene yjgB, ethylene glycol accumulation was improved to 0.91g/L, accompanied with 1.48g/L of PHB accumulation. The disruption of native glycolate oxidase was found to be essential for glycolate production, and the defective recombinant strain produced 0.80g/L glycolate with 1.14g/L PHB in shake flask cultures. These results indicated that H. bluephagenesis has the potential to produce diverse metabolic chemicals from xylose.

Epigenetic alterations in preeclampsia: a focus on microRNA149 and tetrahydrofolate reductase gene polymorphisms in Egyptian women.

Preeclampsia (PE) poses a substantial risk to prenatal and maternal health. Folic acid (FA) and methylenetetrahydrofolate reductase (MTHFR) play roles in DNA methylation and genomic integrity maintenance, with MTHFR polymorphisms potentially impacting PE occurrence. Human microRNA 149 (miR-149) remains underexplored in PE despite its involvement in folate metabolism. This study seeks to evaluate serum miR-149 levels with the MTHFR C677T polymorphism for diagnosing PE. Seventy females aged 28-40 gestational weeks were divided into control and Preeclampsia groups. Serum miR-149 and MTHFR gene levels were evaluated using real-time PCR. Preeclamptic patients showed significantly lower serum miR-149 levels than healthy controls (P ≤ 0.01). PE cases showed a higher frequency of the TT genotype and T allele of the C677T polymorphism (OR = 0.181, 2.882, respectively), implicating them as genetic risk factors. The CT genotype also increased PE risk (OR = 0.26), while no significant difference was observed in the CC genotype. Merging miR-149 and MTHFR polymorphism assessment improves discrimination between healthy and PE groups, offering valuable insights into PE pathogenesis and potential diagnostic strategies.

Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) gene polymorphisms and five related serum molecular levels in 2587 patients: Associated differentially with adverse pregnancy.

The aim of the study is to investigate the relationship between Methylenetetrahydrofolate reductase (MTHFR), methionine synthase reductase (MTRR) polymorphisms, 5 serum related molecular levels and the risk of adverse pregnancies in different genders. Patients aged from 22 to 38 with a history of adverse pregnancy treated in our genetic eugenics clinic of Henan Provincial People's Hospital are selected. The controls aged from 20 to 34 undergoing eugenics examinations in our genetic eugenics clinic that had no history of adverse pregnancy and at least one healthy child are selected. Sanger sequencing and Chemiluminescence Microparticle Immuno Assay (CMIA) are used for detecting the mutations of MTHFR and MTRR and the 5 serum molecular serum levels. In the female group, MTHFR 677C > T is associated with Recurrent spontaneous abortion (RSA) (P = 0.0017), Chromosomal abnormality (CA) (P = 0.0053), Cleft lip and palate (CLP) (P = 0.0326) and Brain dysplasia (BD) (P = 0.0072); MTHFR 1298A > C is associated with Infertility (P = 0.0026) and BD (P = 0.0382); MTRR 66A > G is associated with CLP (P = 0.0131). In the male group, MTHFR 677C > T is associated with RSA (P = 0.0003), Infertility (P = 0.0013), CA (P = 0.0027) and BD (P = 0.0293). In the female group, the genotype of MTHFR 677C > T is associated with RSA (P = 0.0017), CA (P = 0.0014) and BD (P = 0.0021); MTHFR 1298A > C is associated with Infertility (P = 0.0081) and MTRR 66A > G is associated with Infertility (P = 0.0309). In the male group, the genotype of MTHFR 677C > T is associated with RSA (P = 0.0008), Infertility (P = 0.0096) and CA (P = 0.0165) and MTRR 66A > G is associated with Infertility (P = 0.0158) and congenital heart disease (CHD) (P = 0.0218). In the male group, there is statistically significant difference of the serum Homocysteine (Hcy) levels (P < 0.0001) between adverse pregnancy group and controls.In the female group,there is statistically significant difference of the serum vitamin D levels (P = 0.0015) between adverse pregnancy group and controls. Polymorphic variants in MTHFR and MTRR, serum Folic acid (FA), Hcy and B12 levels in the male group and vitamin D levels in the female group are associated differentially with adverse pregnancy.

The Systemic Effect of Ischemia Training and Its Impact on Bone Marrow-Derived Monocytes.

Monocytes are innate immune cells that play a central role in inflammation, an essential component during neovascularization. Our recent publication demonstrated that ischemia training by 24 h unilateral occlusion of the femoral artery (FA) can modify bone marrow-derived monocytes (BM-Mono), allowing them to improve collateral remodeling in a mouse model of hindlimb ischemia. Here, we expand on our previous findings, investigating a potential systemic effect of ischemia training and how this training can impact BM-Mono. BM-Mono from mice exposed to ischemia training (24 h) or Sham (same surgical procedure without femoral artery occlusion-ischemia training) procedures were used as donors in adoptive transfer experiments where recipients were subjected to hindlimb ischemia. Donor cells were divided corresponding to the limb from which they were isolated (left-limb previously subjected to 24 h ischemia and right-contralateral limb). Recipients who received 24 h ischemic-trained monocytes isolated from either limb had remarkable blood flow recovery compared to recipients with Sham monocytes (monocytes isolated from Sham group-no ischemia training). Since these data suggested a systemic effect of ischemic training, circulating extracellular vesicles (EVs) were investigated as potential players. EVs were isolated from both groups, 24 h-trained and Sham, and the former showed increased expression of histone deacetylase 1 (HDAC1), which is known to downregulate 24-dehydrocholesterol reductase (Dhcr24) gene expression. Since we previously revealed that ischemia training downregulates Dhcr24 in BM-Mono, we incubated EVs from 24 h-trained and Sham groups with wild-type (WT) BM-Mono and demonstrated that WT BM-Mono incubated with 24 h-trained EVs had lower gene expression of Dhcr24 and an HDAC1 inhibitor blunted this effect. Next, we repeated the adoptive transfer experiment using Dhcr24 KO mice as donors of BM-Mono for WT mice subjected to hindlimb ischemia. Recipients who received Dhcr24 KO BM-Mono had greater limb perfusion than those who received WT BM-Mono. Further, we focused on the 24 h-trained monocytes (which previously showed downregulation of Dhcr24 gene expression and higher desmosterol) to test the expression of a few genes downstream of the desmosterol pathway, confirm the Dhcr24 protein level and assess its differentiation in M2-like macrophage phenotype. We found that 24 h-trained BM-Mono had greater expression of key genes in the desmosterol pathway, such as liver X receptors (LXRs) and ATP-binding cassette transporter (ABCA1), and we confirmed low protein expression of Dhcr24. Further, we demonstrated that ischemic-trained BM-Mono polarized towards an anti-inflammatory M2 macrophage phenotype. Finally, we demonstrated that 24 h-trained monocytes adhere less to endothelial cells, and the same pattern was shown by WT BM-Mono treated with Dhcr24 inhibitor. Ischemia training leads to a systemic effect that, at least in part, involves circulating EVs and potential epigenetic modification in BM-Mono. These ischemic-trained BM-Mono demonstrated an anti-inflammatory phenotype towards M2 macrophage differentiation and less ability to adhere to endothelial cells, which is associated with the downregulation of Dhcr24 in those cells. These data together suggest that Dhcr24 might be an important target within monocytes to improve the outcomes of hindlimb ischemia.

Consensus QTL map deciphered genes and pathways regulating tolerance to post‐flowering diseases in maize

AbstractPost‐flowering diseases (PFDs), such as ear rot, stalk rot and smut, affect maize yield and quality by damaging the reproductive organs, stalks and seeds. We hypothesized that quantitative trait loci (QTL) associated with different PFDs colocalize and share similar defence mechanisms. Hence, to find a stable consensus meta‐QTL (MQTL) for single or multiple PFDs, MQTL analysis was performed. QTL conferring resistance to PFD reported in 31 independent studies were collated to develop a consensus map. As many as 49 MQTL conferring PFD resistance were projected using appropriate algorithms. Most MQTL regions encompass genes encoding a wide range of defence‐related proteins. MQTL1.1 and MQTL10.5 included QTL/genes for resistance to all PFDs, which supported our hypothesis. Candidate genes for PFDs in MQTL7.1 were associated with pathogenesis‐related 1 protein and mitogen‐activated protein kinase (MAPK) signalling. MQTL5.2 encompassed chalcone flavanone isomerase and cinnamoyl coenzyme A (CoA) reductase genes involved in flavonoid and phenylpropanoid biosynthesis, respectively. Furthermore, MQTL10.4 was found to harbour genes encoding E3 ubiquitin ligase, WRKY‐TF11, calcium‐binding domains and zinc finger motifs. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis reiterated the role of genes within MQTL7.1 in the MAPK signalling pathway, phytohormone signal transduction and plant–pathogen interaction. Hence, we propose that these genes are potential candidates for PFD resistance. Furthermore, 75% of the genes within the MQTL showed orthology with sorghum and rice, indicating that these genes were conserved across species. The role of 27 MQTL, including the six most significant MQTL, was confirmed with reported genome‐wide association study (GWAS) results. Thus, the hotspots associated with PFDs identified in our study could be reliably used in marker‐assisted breeding for PFD resistance.

Transcriptome and Metabolome Analyses Reveal Response Mechanisms to Alternaria brassicicola-Induced Black Spot Disease in Diverse Chinese Cabbage Genotypes

Chinese cabbage (Brassica rapa L. ssp. pekinensis) is an important food crop. However, its growth and development are commonly impacted by black spot disease. To examine the response mechanisms of Chinese cabbage to black spot disease, transcriptome and metabolome sequencing were performed on the leaves of Chinese cabbage genotypes J405 (resistant) and B214 (susceptible), 48 h post-infection (hpi) with Alternaria brassicicola. Expression of essential genes in the jasmonic acid, cytokinin, and auxin signaling pathways of both Chinese cabbage genotypes was inhibited. The expression of the pathogenesis-related protein 1 (PR1) gene mediated by the salicylic acid pathway is inhibited in the Chinese cabbage genotype B214. The basic endochitase B (CHIB) gene in the ethylene pathway of both Chinese cabbage genotypes was upregulated. The accumulation of reactive oxygen species in the disease spots of Chinese cabbage genotype J405 was greater than in genotype B214. The respiratory burst oxidase (RBOH) gene in the reactive oxygen species metabolic pathway was significantly upregulated in genotype J405, while no change was observed in genotype B214. We found that oxidation-reduction-related genes such as type-2 peroxiredoxin genes, NADPH-dependent thioredoxin reductase genes, glutathione peroxidase genes, and glutathione S-transfer genes were differentially expressed across both Chinese cabbage genotypes at 48 hpi. Metabolomics demonstrated that delta-tocopherol and S-hexyl glutathione were all downregulated in genotype J405, while they were upregulated in genotype B214. This approach also identified differential expression of genes in the carotenoid biosynthesis pathway, the glycinebetaine biosynthesis pathway, as well as in the specific sulfur glycoside metabolism pathway. These findings indicate that ethylene signaling is important in the hormone signaling regulatory network-mediated disease resistance and defense in Chinese cabbage. When facing pathogen infection, hormone transduction pathways associated with growth and development in Chinese cabbage are inhibited. The accumulation of reactive oxygen species and the outbreak of various secondary metabolites may endow the Chinese cabbage genotype J405 with increased resistance to black spot disease.

Population genomics of Plasmodium ovale species in sub-Saharan Africa.

Plasmodium ovale curtisi (Poc) and Plasmodium ovale wallikeri (Pow) are relapsing malaria parasites endemic to Africa and Asia that were previously thought to represent a single species. Amid increasing detection of ovale malaria in sub-Saharan Africa, we performed a population genomic study of both species across the continent. We conducted whole-genome sequencing of 25 isolates from Central and East Africa and analyzed them alongside 20 previously published African genomes. Isolates were predominantly monoclonal (43/45), with their genetic similarity aligning with geography. Pow showed lower average nucleotide diversity (1.8×10-4) across the genome compared to Poc (3.0×10-4) (p < 0.0001). Signatures of selective sweeps involving the dihydrofolate reductase gene were found in both species, as were signs of balancing selection at the merozoite surface protein 1 gene. Differences in the nucleotide diversity of Poc and Pow may reflect unique demographic history, even as similar selective forces facilitate their resilience to malaria control interventions.

Efficient partial denitrification-anammox process enabled by a novel denitrifier with truncated nitrite reduction pathway

Partial denitrification coupled with anaerobic ammonium oxidation (PD-anammox) is a promising technology for cost-effective nitrogen removal from wastewater. Nitrite availability is crucial to anammox performance but often limited by the slow partial denitrification process. Here we report an efficient PD-anammox system driven by the novel denitrifier Bacillus velezensis C1–3 with truncated nitrite reduction pathway. Whole-genome sequencing analysis revealed that the lack of nitrite reductase genes nirS/nirK and norBC in strain C1–3 enabled nitrite accumulation without the need for precise control of carbon dosage. By coupling it with anammox sludge, over 79 % total nitrogen (TN) removal was stably achieved, under a TN loading rate of 660 mg/L/d and a carbon/nitrogen ratio below 1.0. Mechanism explorations indicate that the niche differentiation of C1–3 and anammox bacteria facilitated their mutualism while avoiding nitrite competition. This study demonstrates a novel strategy for establishing efficient PD-anammox process by harnessing the unique metabolic deficiency of denitrifiers, shedding light on the development of stable and sustainable biological nitrogen removal technologies with minimal carbon footprint.