Transferase Gene Research Articles

A Novel Biosynthetic Strategy for Ginsenoside Ro: Construction of a Metabolically Engineered Saccharomyces cerevisiae Strain Using a Newly Identified UGAT Gene from Panax ginseng as the Key Enzyme Gene and Optimization of Fermentation Conditions.

Ginsenoside Ro, as one of the few oleanane-type ginsenosides, is well known for its unique molecular structure and biological activities. Currently, research on the biosynthesis of ginsenoside Ro is still in its early stages. Therefore, the establishment of a new ginsenoside Ro cell factory is of great significance for the in-depth development and utilization of genes related to ginsenoside Ro synthesis, as well as for the exploration of pathways to obtain ginsenoside Ro. In this study, we cloned endogenous constitutive promoters, terminators, and other genetic elements from S. cerevisiae BY4741. These elements were then sequentially assembled with the uridine diphosphate glucuronic acid transferase gene identified in our previously study (PgUGAT252645) and several other reported key enzyme genes, to construct DNA fragments used for integration into the genome of S. cerevisiae BY4741. By sequentially transferring these DNA fragments into chemically competent cells of engineering strains and conducting screening and target product detection, we successfully constructed an engineered S. cerevisiae strain (BY-Ro) for ginsenoside Ro biosynthesis using S. cerevisiae BY4741 as the host cell. Strain BY-Ro produced 253.32 μg/L of ginsenoside Ro under optimal fermentation conditions. According to subsequent measurements and calculations, this equates to 0.033 mg/g DCW, corresponding to approximately 31% of the ginsenoside Ro content found in plant samples. This study not only included a deeper investigation into the function of PgUGAT252645 but also provides a novel engineering platform for ginsenoside Ro biosynthesis.

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.

Resistance to carbapenems in the urban soil isolate Cupriavidus taiwanensis S2-1-W is associated with OXA-1206, a newly discovered carbapenemase.

Cupriavidus isolates are found in environmental and clinical samples and are often resistant to carbapenems, which are last-resort antibiotics. However, their carbapenem-resistance molecular mechanisms remain unknown. This study aimed to (i) characterize and sequence the carbapenem-resistant soil isolate Cupriavidus taiwanensis S2-1-W to uncover its antibiotic resistance determinants; and (ii) clone and characterize a putative novel carbapenemase gene identified in this isolate. Antibiotic susceptibility testing of C. taiwanensis S2-1-W revealed that it was resistant to most carbapenems, other β-lactams, and aminoglycosides tested. Genome sequencing of this isolate revealed a complex chromosomal resistome that included multidrug efflux pump genes, one aminoglycoside transferase gene, and three β-lactamase genes. Among them, we identified a novel putative class D β-lactamase gene (blaOXA-1206) that is highly conserved among other sequenced C. taiwanensis isolates. Cloning and characterization of blaOXA-1206 confirmed that it encodes for a newly discovered carbapenemase (OXA-1206) that confers resistance to carbapenems and other β-lactams. Carbapenem-resistance in C. taiwanensis S2-1-W is associated with a newly discovered carbapenemase, OXA-1206.

Decoding eggplant fruit: Multi-omics profiling of caffeoyl-CoA-3-OMT expression

Eggplant (Solanum melongena L.) is a rich source of health-promoting phenolic acids, mainly chlorogenic acid (CGA), and trace elements. CGA has been shown to have antioxidant, anti-inflammatory, neuroprotective, cardioprotective, anticancer, and antidiabetic properties. The natural genome of eggplants contains essential genes for beneficial traits like drought tolerance, disease resistance, and high concentrations of medicinal substances. Transcriptomic analysis of eggplant overexpressing the hydroxycinnamoyl CoA quinate hydroxycinnamoyl transferase (HQT) gene revealed upregulation of 2165 genes, including three similar to HQT and cinnamate-4-hydroxylase (C4H). Sequence similarity analysis showed homology to caffeoyl-CoA O-methyltransferases, key enzymes in the phenylpropanoid pathway leading to CGA biosynthesis. Gene ontology and KEGG pathway analysis identified 5 highly upregulated glycosyltransferase family 43 genes (650.3-fold change). Glycosyltransferases like UDP-glucose:cinnamate glucosyltransferase and cinnamate-glucose 4′-O-glucosyltransferase are crucial for CGA production in eggplant. qRT-PCR validated the potential upregulation of HQT and C4H in transgenic eggplants. Comparative analysis revealed eggplant has the highest CGA content (5–8.1 g/kg dry weight) among vegetables, with foliar CGA acting as a natural insecticide. CGA offers antioxidant, hypoglycemic, antiviral, and hepatoprotective benefits to humans. This study highlights the role of HQT and C4H in elevating the medicinal properties of eggplant through CGA biosynthesis pathway engineering.

Responses of Brassica napus to soil cadmium under elevated CO2 concentration based on rhizosphere microbiome, root transcriptome and metabolome

Rising atmospheric carbon dioxide (CO2) and soil heavy metal pollution affect crop safety and production. Exposure to elevated CO2 (ECO2) increases cadmium (Cd) uptake in some crops like wheat and rice, however, it remains unclear how ECO2 affects Cd uptake by Brassica napus. Here, we investigated the responses of B. napus seedlings exposed to ECO2 and Cd through analyses of physiology, transcriptome, metabolome, and rhizosphere microbes. Compared with Cd-stress alone (Cd50_ACO2), ECO2 boosted the uptake of Cd by B. napus roots by 38.78% under coupled stresses (Cd50_ECO2). The biomass and leaf chlorophyll a content increased by 38.49% and 79.66% respectively in Cd50_ECO2 relative to Cd50_ACO2. Activities of superoxide dismutase (SOD) and peroxidase (POD) enhanced by 8.42% and 185.01%, respectively, while glutathione (GSH) and ascorbic acid (AsA) contents increased by 16.44% and 52.48%, and abundances of rhizosphere microbes changed significantly under coupled stresses (Cd50_ECO2) relative to Cd-stress alone (Cd50_ACO2). Also, the upregulation of glutathione, glutathione transferase genes, and heavy metal ATPase expression promoted the detoxification effect of rapeseed on Cd. Changes in the expression of transcription factors like MAPK, WRKY, BAK1 and PR1, as well as changes in metabolic pathways like β-alanine, may be involved in the regulatory mechanism of stress response. These findings provide new insights for studying the regulatory mechanism of rapeseed under ECO2 on soil Cd stress, and also provide a basis for further research on Cd tolerant rapeseed varieties in the future climate context.

Mini Review: the non-neuronal cardiac cholinergic system in type-2 diabetes mellitus.

Diabetic heart disease remains the leading cause of death in individuals with type-2 diabetes mellitus (T2DM). Both insulin resistance and metabolic derangement, hallmark features of T2DM, develop early and progressively impair cardiovascular function. These factors result in altered cardiac metabolism and energetics, as well as coronary vascular dysfunction, among other consequences. Therefore, gaining a deeper understanding of the mechanisms underlying the pathophysiology of diabetic heart disease is crucial for developing novel therapies for T2DM-associated cardiovascular disease. Cardiomyocytes are equipped with the cholinergic machinery, known as the non-neuronal cardiac cholinergic system (NNCCS), for synthesizing and secreting acetylcholine (ACh) as well as possessing muscarinic ACh receptor for ACh binding and initiating signaling cascade. ACh from cardiomyocytes regulates glucose metabolism and energetics, endothelial function, and among others, in an auto/paracrine manner. Presently, there is only one preclinical animal model - diabetic db/db mice with cardiac-specific overexpression of choline transferase (Chat) gene - to study the effect of activated NNCCS in the diabetic heart. In this mini-review, we discuss the physiological role of NNCCS, the connection between NNCCS activation and cardiovascular function in T2DM and summarize the current knowledge of S-Nitroso-NPivaloyl-D-Penicillamine (SNPiP), a novel inducer of NNCCS, as a potential therapeutic strategy to modulate NNCCS activity for diabetic heart disease.

Physiology, Biochemistry, and Transcriptomics Jointly Reveal the Phytotoxicity Mechanism of Acetochlor on Pisum sativum L.

Acetochlor, as a commonly used pre-emergent herbicide, can be toxic to crops and affect production if used improperly. However, the toxic mechanism of acetochlor on plants is not fully understood. The present study used a combination of transcriptomic analysis and physiological measurements to investigate the effects of short-term (15-day) exposure to different concentrations of acetochlor (1, 10, 20 mg/kg) on the morphology, physiology, and transcriptional levels of pea seedlings, aiming to elucidate the toxic response and resistance mechanisms in pea seedlings under herbicide stress. The results showed that the toxicity of acetochlor to pea seedlings was dose-dependent, manifested as dwarfing and stem base browning with increasing concentrations, especially at 10 mg/kg and above. Analysis of the antioxidant system showed that from the 1 mg/kg treatment, malondialdehyde, superoxide dismutase, peroxidase, and glutathione peroxidase in peas increased with increasing concentrations of acetochlor, indicating oxidative damage. Analysis of the glutathione (GSH) metabolism system showed that under 10 mg/kg treatment, the GSH content of pea plants significantly increased, and GSH transferase activity and gene expression were significantly induced, indicating a detoxification response in plants. Transcriptomic analysis showed that after acetochlor treatment, differentially expressed genes in peas were significantly enriched in the phenylpropane metabolic pathway, and the levels of key metabolites (flavonoids and lignin) were increased. In addition, we found that acetochlor-induced dwarfing of pea seedlings may be related to gibberellin signal transduction. Environ Toxicol Chem 2024;43:2005-2019. © 2024 SETAC.

Effect of O-Polysaccharide Modifications on Successful Plant Colonization by Bacteria

O-polysaccharides of gram-negative bacteria are a highly variable component of the lipopolysaccharide molecules located at the cell wall surface and involved in microbial interaction with plant and animal cells. Activity of prophage genes often results in various non-stoichiometric modifications (methylation, acetylation, etc.) of glycans at bacterial cell surface. The share of modified O-polysaccharides increases during the stationary growth phase and results in increased hydrophobicity of microbial surface. Bacterial cells with different hydrophobicity showed difference in attachment to plant roots. Increased cell hydrophobicity index was found to result in a significant increase in the number of adsorbed microorganisms per unit root length. Thus, acetyl transferase and methyl transferase genes of viral origin may be indirectly involved in successful colonization of plant roots by rhizosphere bacteria.

AT-hook motif nuclear localized transcription factors function redundantly in promoting root growth through modulation of redox homeostasis.

Maintaining an optimal redox status is essential for plant growth and development, particularly when the plants are under stress. AT-hook motif nuclear localized (AHL) proteins are evolutionarily conserved transcription factors in plants. Much of our understanding about this gene family has been derived from studies on clade A members. To elucidate the functions of clade B genes, we first analyzed their spatial expression patterns using transgenic plants expressing a nuclear localized GFP under the control of their promoter sequences. AHL1, 2, 6, 7, and 10 were further functionally characterized owing to their high expression in the root apical meristem. Through mutant analyses and transgenic studies, we showed that these genes have the ability to promote root growth. Using yeast one-hybrid and dual luciferase assays, we demonstrated that AHL1, 2, 6, 7, and 10 are transcription regulators and this activity is required for their roles in root growth. Although mutants for these genes did not showed obvious defects in root growth, transgenic plants expressing their fusion proteins with the SRDX repressor motif exhibited a short-root phenotype. Through transcriptome analysis, histochemical staining and molecular genetics experiments, we found that AHL10 maintains redox homeostasis via direct regulation of glutathione transferase (GST) genes. When the transcript level of GSTF2, a top-ranked target of AHL10, was reduced by RNAi, the short-root phenotype in the AHL10-SRDX expressing plant was largely rescued. These results together suggest that AHL genes function redundantly in promoting root growth through direct regulation of redox homeostasis.

Identification and characterization of HCT genes in blackberry: Overexpression of RuHCT1 enhances anthocyanin contents

Emerging as a new generation of economic fruit, blackberries are rich in flavonoids and anthocyanins. Acylation can change the pharmacological activity and structural stability of anthocyanins and is of great significance to plant growth and secondary metabolism. In this study, based on the transcriptome data of the blackberry fruit, five blackberry hydroxycinnamoyl transferase (HCT) genes were screened and identified, all of which belong to the BAHD superfamily. Among them, RuHCT1, RuHCT2 and RuHCT3 have similar tertiary structures and functions. RuHCT1, the gene with the largest difference in expression between immature and mature blackberry fruits, was selected for overexpression research. The results showed that the content of anthocyanin in the leaves of transgenic plants was significantly increased, while the content of secondary metabolites such as lignan and chlorogenic acid was decreased. Moreover, the expression levels of the NtCCOMT, NtCHS and NtCYP98A genes in transgenic tobacco were lower than those in nontransgenic plants. In conclusion, RuHCT1 may be an important structural gene regulating anthocyanin synthesis in blackberry. RuHCT1 may also inhibit lignan synthesis and affect the expression of other key structural genes. This study provides a theoretical reference regarding the biosynthesis and regulatory mechanisms of anthocyanins in blackberry, contributing to the breeding of new blackberry cultivars with high anthocyanin content.

Colistin Resistance Mediated by Mcr-3-Related Phosphoethanolamine Transferase Genes in Aeromonas Species Isolated from Aquatic Environments in Avaga and Pakro Communities in the Eastern Region of Ghana.

Colistin is classified by the World Health Organization (WHO) as a critically important and last-resort antibiotic for the treatment of infections caused by carbapenem-resistant bacteria. However, colistin resistance mediated by chromosomal mutations or plasmid-linked mobilized colistin resistance (mcr) genes has emerged. Thirteen mcr-positive Aeromonas species isolated from water samples collected in Eastern Ghana were analyzed using whole-genome sequencing (WGS). Antimicrobial susceptibility was tested using the broth microdilution method. Resistome analysis was performed in silico using a web-based platform. The minimum inhibitory concentration (MIC) of colistin for all except three isolates was >4 µg/mL. Nine new sequence types were identified and whole-genome analysis revealed that the isolates harbored genes (mcr-3-related genes) that code for Lipid A phosphoethanolamine transferases on their chromosomes. BLAST analysis indicated that the amino acid sequences of the mcr-3-related genes detected varied from those previously reported and shared 79.04-99.86% nucleotide sequence identity with publicly available mcr-3 variants and mcr-3-related phosphoethanolamine transferases. Analysis of the genetic context of mcr-3-related genes revealed that the genetic environment surrounding mcr-3-related genes was diverse among the different species of Aeromonas but conserved among isolates of the same species. Mcr-3-related-gene-IS-mcr-3-related-gene segment was identified in three Aeromonas caviae strains. The presence of mcr-3-related genes close to insertion elements is important for continuous monitoring to better understand how to control the mobilization and dissemination of antibiotic resistance genes.

Screening of the PA14NR Transposon Mutant Library Identifies Genes Involved in Resistance to Bacteriophage Infection in Pseudomomas aeruginosa.

Multidrug-resistant P. aeruginosa infections pose a serious public health threat due to the rise in antimicrobial resistance. Phage therapy has emerged as a promising alternative. However, P. aeruginosa has evolved various mechanisms to thwart phage attacks, making it crucial to decipher these resistance mechanisms to develop effective therapeutic strategies. In this study, we conducted a forward-genetic screen of the P. aeruginosa PA14 non-redundant transposon library (PA14NR) to identify dominant-negative mutants displaying phage-resistant phenotypes. Our screening process revealed 78 mutants capable of thriving in the presence of phages, with 23 of them carrying insertions in genes associated with membrane composition. Six mutants exhibited total resistance to phage infection. Transposon insertions were found in genes known to be linked to phage-resistance such as galU and a glycosyl transferase gene, as well as novel genes such as mexB, lasB, and two hypothetical proteins. Functional experiments demonstrated that these genes played pivotal roles in phage adsorption and biofilm formation, indicating that altering the bacterial membrane composition commonly leads to phage resistance in P. aeruginosa. Importantly, these mutants displayed phenotypic trade-offs, as their resistance to phages inversely affected antibiotic resistance and hindered biofilm formation, shedding light on the complex interplay between phage susceptibility and bacterial fitness. This study highlights the potential of transposon mutant libraries and forward-genetic screens in identifying key genes involved in phage-host interactions and resistance mechanisms. These findings support the development of innovative strategies for combating antibiotic-resistant pathogens.

Enhancement of production of glycoalkaloids by elicitors along with characterization of gene expression of pathways in Solanum xanthocarpum

Solanum xanthocarpum fruits are used in the treatment of cough, fever, and heart disorders. It possesses antipyretic, hypotensive, antiasthmatic, aphrodisiac and antianaphylactic properties. In the present study, 24 elicitors (both biotic and abiotic) were used to enhance the production of glycoalkaloids in cell cultures of S. xanthocarpum. Four concentrations of elicitors were added into the MS culture medium. The maximum accumulation (5.56-fold higher than control) of demissidine was induced by sodium nitroprusside at 50 mM concentration whereas the highest growth of cell biomass (4.51-fold higher than control) stimulated by systemin at 30 mM concentration. A total of 17 genes of biosynthetic pathways of glycoalkaloids were characterized from the cells of S. xanthocarpum. The greater accumulation of demissidine was confirmed with the expression analysis of 11 key biosynthetic pathway enzymes e.g., acetoacetic-CoA thiolase, 3- hydroxy 3-methyl glutaryl synthase, β-hydroxy β-methylglutaryl CoA reductase, mevalonate kinase, farnesyl diphosphate synthase, squalene synthase, squalene epoxidase, squalene-2,3- epoxide cyclase, cycloartenol synthase, UDP-glucose: solanidine glucosyltransferase and UDP-rhamnose: solanidine rhamno-galactosyl transferase. The maximum expression levels of UDP-rhamnose: solanidine rhamno-galactosyl transferase gene was recorded in this study.

Effects of imidacloprid combined with validamycin on the population fitness and symbiotic of Nilaparvata lugens (Hemiptera: Delphacidae)

Using a high-efficiency insecticide in combination with fungicides that have different mechanisms of action is a conventional method in the current management of brown planthopper (BPH) resistance. In this study, we investigate the separate and combined effects of the low-toxicity fungicide validamycin and the non-cross-resistant insecticide imidacloprid on the fitness and symbiosis of BPH. These research results indicate that when the proportion of active ingredients in validamycin is combined with imidacloprid at a ratio of 1:30, the toxicity ratio and co-toxicity coefficient are 1.34 and 691.73, respectively, suggesting that the combination has a synergistic effect on the control of BPH. The number of yeast-like symbiotic (YLS) and dominant symbiotic (Noda) in the imidacloprid + validamycin groups were significantly lower than the other three treatment groups (validamycin, imidacloprid, and water). The results of the study on population fitness show that the lifespan of the BPH population in validamycin, imidacloprid, and imidacloprid + validamycin was shortened. Notably, the BPH populations in the imidacloprid + validamycin groups were significantly lower than other groups in terms of average generation cycle, intrinsic growth rate, net reproduction rate, finite rate of increase, and fitness. The Real-time quantitative PCR showed that validamycin and imidacloprid + validamycin can significantly inhibit the expression of the farnesyl diphosphate farnesyl transferase gene (EC2.5.1.21) and uricase gene (EC1.7.3.3), with imidacloprid + validamycin demonstrating the most pronounced inhibitory effect. Our research results can provide insights and approaches for delaying resistance and integrated management of BPH.

Integration of targeted metabolome and transcript profiling of Pseudomonas syringae-triggered changes in defence-related phytochemicals in oat plants

Main conclusionA gene-to-metabolite approach afforded new insights regarding defence mechanisms in oat plants that can be incorporated into plant breeding programmes for the selection of markers and genes related to disease resistance.Monitoring metabolite levels and changes therein can complement and corroborate transcriptome (mRNA) data on plant–pathogen interactions, thus revealing mechanisms involved in pathogen attack and host defence. A multi-omics approach thus adds new layers of information such as identifying metabolites with antimicrobial properties, elucidating metabolomic profiles of infected and non-infected plants, and reveals pathogenic requirements for infection and colonisation. In this study, two oat cultivars (Dunnart and SWK001) were inoculated with Pseudomonas syringae pathovars, pathogenic and non-pathogenic on oat. Following inoculation, metabolites were extracted with methanol from leaf tissues at 2, 4 and 6 days post-infection and analysed by multiple reaction monitoring (MRM) on a triple quadrupole mass spectrometer system. Relatedly, mRNA was isolated at the same time points, and the cDNA analysed by quantitative PCR (RT-qPCR) for expression levels of selected gene transcripts associated with avenanthramide (Avn) biosynthesis. The targeted amino acids, hydroxycinnamic acids and Avns were successfully quantified. Distinct cultivar-specific differences in the metabolite responses were observed in response to pathogenic and non-pathogenic strains. Trends in aromatic amino acids and hydroxycinnamic acids seem to indicate stronger activation and flux through these pathways in Dunnart as compared to SWK001. A positive correlation between hydroxycinnamoyl-CoA:hydroxyanthranilate N-hydroxycinnamoyl transferase (HHT) gene expression and the abundance of Avn A in both cultivars was documented. However, transcript profiling of selected genes involved in Avn synthesis did not reveal a clear pattern to distinguish between the tolerant and susceptible cultivars.Graphical abstract

Improving Surfactin Production in Bacillus subtilis 168 by Metabolic Engineering.

Surfactin is widely used in the petroleum extraction, cosmetics, biopharmaceuticals and agriculture industries. It possesses antibacterial and antiviral activities and can reduce interfacial tension. Bacillus are commonly used as production chassis, but wild-type Bacillus subtilis 168 cannot synthesise surfactin. In this study, the phosphopantetheinyl transferase (PPTase) gene sfp* (with a T base removed) was overexpressed and enzyme activity was restored, enabling B. subtilis 168 to synthesise surfactin with a yield of 747.5 ± 6.5 mg/L. Knocking out ppsD and yvkC did not enhance surfactin synthesis. Overexpression of predicted surfactin transporter gene yfiS increased its titre to 1060.7 ± 89.4 mg/L, while overexpression of yerP, ycxA and ycxA-efp had little or negative effects on surfactin synthesis, suggesting YfiS is involved in surfactin efflux. By replacing the native promoter of the srfA operon encoding surfactin synthase with three promoters, surfactin synthesis was significantly reduced. However, knockout of the global transcriptional regulator gene codY enhanced the surfactin titre to 1601.8 ± 91.9 mg/L. The highest surfactin titre reached 3.89 ± 0.07 g/L, with the yield of 0.63 ± 0.02 g/g DCW, after 36 h of fed-batch fermentation in 5 L fermenter. This study provides a reference for further understanding surfactin synthesis and constructing microbial cell factories.

Analysis of the virulence and genetic differences of carbapenem-resistant Acinetobacter baumannii epidemic clones

Objective: To evaluate the virulence levels of carbapenem-resistant Acinetobacter baumannii ST191, ST195, and ST208, and to analyze the differences in virulence factors among these epidemic clones. Methods: The study involved the genomic sequencing of 233 Acinetobacter baumannii strains that were isolated from the Fifth Medical Center of the Chinese People's Liberation Army General Hospital (North Hospital) between 2011 and 2019. The genomic data was cross-referenced with the Virulence Factor Database (VFDB) to examine the presence of virulence genes in the strains. Furthermore, a Galleria mellonella infection survival model was used to evaluate the virulence levels of the strains, and the association between virulence levels and virulence genes was analyzed. Results: The study included 38 strains of the ST191 clone, 104 strains of the ST195 clone, and 91 strains of the ST208 clone. In the Galleria mellonella infection survival experiment, the average mortality rate for ST191 was 23.0%, with 3 (7.9%) highly virulent strains. For ST195, the average mortality rate was 53.0%, with 34 (32.7%) highly virulent strains. For ST208, the average mortality rate was 47.0%, with 20 (21.9%) highly virulent strains. There was a significant statistical difference in mortality rates between ST191 and ST195 (χ2=13.9, P<0.001) as well as between ST191 and ST208 (χ2=15.2, P<0.001). A comparison of the strains with the VFDB revealed significant differences in the virulence genes carried by the clones. Specifically, the type Ⅵ secretion system-related genes (clpV/tssH, hcp/tssD, tagX, tssA, tssB, tssC, tssE, tssF, tssG, tssK, ssL, tssM) and the sugar transferase gene ACICU_RS00475 were found to be universally absent in ST191 strains (0%) while being prevalent in ST195 (100.0%) and ST208 (>82.0%) strains. Statistical analysis revealed an association between the mortality rate of the clones and the presence of virulence genes(clpV/tssH P<0.001, hcp/tssD P=0.001, tagX P<0.001, tssA P<0.001, tssB P=0.001, tssC P=0.001, tssE P=0.001, tssF P=0.001, tssG P<0.001, tssK P<0.001, tssL P<0.001, tssM P=0.001, ACICU_RS00475 P=0.001). Conclusion: Among the carbapenem-resistant epidemic clones of Acinetobacter baumannii, the ST191 clone shows lower mortality rates in Galleria mellonella, possibly because of the lack of type Ⅵ secretion system and sugar transferase genes.

Exploiting Metabolic Defects in Glioma with Nanoparticle-Encapsulated NAMPT Inhibitors.

The treatment of primary central nervous system tumors is challenging due to the blood-brain barrier and complex mutational profiles, which is associated with low survival rates. However, recent studies have identified common mutations in gliomas [isocitrate dehydrogenase (IDH)-wild-type and mutant, WHO grades II-IV; with grade IV tumors referred to as glioblastomas (GBM)]. These mutations drive epigenetic changes, leading to promoter methylation at the nicotinic acid phosphoribosyl transferase (NAPRT) gene locus, which encodes an enzyme involved in generating NAD+. Importantly, NAPRT silencing introduces a therapeutic vulnerability to inhibitors targeting another NAD+ biogenesis enzyme, nicotinamide phosphoribosyl transferase (NAMPT), rationalizing a treatment for these malignancies. Multiple systemically administered NAMPT inhibitors (NAMPTi) have been developed and tested in clinical trials, but dose-limiting toxicities-including bone marrow suppression and retinal toxicity-have limited their efficacy. Here, we report a novel approach for the treatment of NAPRT-silenced GBMs using nanoparticle (NP)-encapsulated NAMPTis administered by convection-enhanced delivery (CED). We demonstrate that GMX1778 (a NAMPTi) can be formulated in degradable polymer NPs with retention of potency for NAMPT inhibition and anticancer activity in vitro, plus sustained drug release in vitro and in vivo. Direct injection of these drugs via CED into the brain is associated with reduced retinal toxicity compared with systemic administration. Finally, we show that CED of NP-encapsulated GMX1778 to NAPRT-silenced intracranial GBM xenografts in mice exhibit significant tumor growth delay and extends survival. These data support an approach to treat gliomas harboring defects in NAD+ metabolism using CED of NP-encapsulated NAMPTis to greatly improve the therapeutic index and treatment efficacy for this class of drugs.

Elucidation of novel drought-responsive genes from tuber transcriptome of cassava under water deficit stress

Cassava (Manihot esculenta Carntz) is the major starchy root crop grown in the tropical parts of the world. Two cassava clones contrasting for their drought tolerance capacity (8S501- drought tolerant and H97-drought sensitive) were selected and grown in the field for studying the agronomical and molecular changes in both the clones under drought stress conditions. A reduction in the number of tuberous roots per plant, tuberous root length, average single tuber weight and tuber yield per plant was observed under drought stress when compared with the control conditions and also significantly lower mean values were observed for the sensitive clone H97 than that of the tolerant clone 8S501 when measured at 60 days of stress. Transcriptome sequencing of the tuber tissues of the two clones was done at 60 days of imposing drought stress. Different genes belonging to various groups like aquaporins, transporter genes, growth regulator related genes, calcium binding and mineral transfer-related genes, transferase genes and transcription factors were differentially expressed in the tubers under drought stress. Comparative transcriptomics revealed that acyl-CoA oxidase, primary-amine oxidase, glutathione peroxidase, vesicle transport, late embryogenesis abundant protein related, histone demethylase, BR-signaling kinase, palmitoyltransferase, DNA mismatch repair protein, heat shock protein related, starch/sucrose metabolic pathway related and MFS transporter genes were differentially expressed in the tubers of the tolerant clone 8S501 relative to the susceptible clone H97.

Genome wide identification and characterization of Isopentenyl transferase (IPT) gene family associated with cytokinin synthesis in rice

Genome wide identification and characterization of Isopentenyl transferase (IPT) gene family associated with cytokinin synthesis in rice