Resistance-related Genes Research Articles

Doxorubicin and topotecan resistance in ovarian cancer: Gene expression and microenvironment analysis in 2D and 3D models.

This study explores the mechanisms underlying chemotherapy resistance in ovarian cancer (OC) using doxorubicin (DOX) and topotecan (TOP)-resistant cell lines derived from the drug-sensitive A2780 ovarian cancer cell line. Both two-dimensional (2D) monolayer cell cultures and three-dimensional (3D) spheroid models were employed to examine the differential drug responses in these environments. The results revealed that 3D spheroids demonstrated significantly higher resistance to DOX and TOP than 2D cultures, suggesting a closer mimicry of in vivo tumour conditions. Molecular analyses identified overexpression of essential drug resistance-related genes, including MDR1 and BCRP, and extracellular matrix (ECM) components, such as MYOT and SPP1, which were more pronounced in resistant cell lines. MDR1 and BCRP overexpression contribute to chemotherapy resistance in OC by expelling drugs like DOX and TOP. Targeting these transporters with inhibitors or gene silencing could improve drug efficacy, making them key therapeutic targets to enhance treatment outcomes for drug-resistant OC. The study further showed that EMT-associated markers, including VIM, SNAIL1, and SNAIL2, were upregulated in the 3D spheroids, reflecting a more mesenchymal phenotype. These findings suggest that factors beyond gene expression, such as spheroid architecture, cell-cell interactions, and drug penetration, contribute to the enhanced resistance observed in 3D cultures. These results highlight the importance of 3D cell culture models for a more accurate representation of tumour drug resistance mechanisms in ovarian cancer, providing valuable insights for therapeutic development.

Prevalence and molecular characteristics of colistin-resistant isolates among carbapenem-resistant Klebsiella pneumoniae in Central South China: a multicenter study

BackgroundThe emergence of colistin resistance in carbapenem-resistant Klebsiella pneumoniae (CRKP) is a significant public health concern, as colistin has been the last resort for treating such infections. This study aimed to investigate the prevalence and molecular characteristics of colistin-resistant CRKP isolates in Central South China.MethodsCRKP isolates from twelve hospitals in Central South China were screened for colistin resistance using broth microdilution. The epidemiological characteristics, virulome, resistome, plasmid replicons and two-component systems associated with colistin resistance of colistin-resistant isolates were explored by whole-genome sequencing. The mgrB gene and the relative expression of the pmrC and pmrK genes were analyzed by polymerase chain reaction (PCR) and real-time quantitative PCR, respectively. The bacterial virulence was evaluated through a Galleria mellonella larvae infection model.ResultsOf the 429 nonduplicate CRKP isolates, 26 (6.1%) were colistin-resistant and they included eight clonal clusters. Six distinct sequence type (ST)-capsule loci (KL) types were identified: ST11-KL64, ST11-KL47, ST963-KL16, ST307-KL102, ST751-KL64 and ST5254-KL47. 88.5% (23/26) of them were found to carry at least one carbapenemase gene, including blaKPC−2 (65.4%, 17/26) and blaNDM−1 (7.7%, 2/26), as well as coharbouring blaKPC−2 and blaNDM−1 (15.4%, 4/26). Diverse mutations of colistin resistance-related genes were observed, with mgrB inactivation by insertions and the T157P deleterious mutation in pmrB being detected in 57.7% and 42.3% of the colistin-resistant isolates, respectively. In addition, a novel deleterious mutation, R248P, in the crrB gene was found in two ST11 isolates. 88.5% of the 26 isolates presented an increase in pmrK transcription, and 69.2% of them had an overexpression of the pmrC gene. All the 16 ST11-KL64 isolates and one ST751-KL64 isolate (65.4%, 17/26) carried at least two hypervirulence biomarkers and showed high virulence in vivo.ConclusionsThis study highlights the presence of different colistin resistance mechanisms in isolates belonging to the same clone and identified multiple clonal transmission clusters in colistin resistant isolates, including the globally high-risk ST11 and ST307 clones, of which a significant proportion exhibited high virulence. Consequently, it is crucial to enforce measures to prevent the ongoing spread of colistin resistance.

OsMYB1 antagonizes OsSPL14 to mediate rice resistance to brown planthopper and Xanthomonas oryzae pv. oryzae.

OsMYB1 negatively mediates rice resistance to brown planthopper and rice blight. Additionally, OsMYB1 interacts with OsSPL14 and antagonizes its function by oppositely regulating downstream resistance-related genes. In their natural habitats, plants are concurrently attacked by different biotic factors. Xanthomonas oryzae pv. oryzae (Xoo) is a pathogen that severely deteriorates rice yield and quality, and brown planthopper (BPH; Nilaparvata lugens) is a rice specific insect pest with the damage topping other pathogens. Although genes for respective resistance to BPH and Xoo have been widely reported, few studies pay attention to simultaneous resistance to both. In this study, we identified a MYB transcription factor, OsMYB1, which exhibited diverse transcriptional regulatory capabilities and a negative regulatory role in resistance to both BPH and Xoo. Biochemical and genetic analysis proved OsMYB1 to be a TF that could interact with OsSPL14, a positive regulator of rice resistance to Xoo. OsSPL14 mutants showed increased sensitivity to BPH, suggesting that OsSPL14 is contrary to OsMYB1 in regulating rice resistance to these two biotic stresses. Consistently, OsMYB1 and OsSPL14 displayed opposite functions in regulating defense-related genes. OsMYB1 can form transcription regulation complexes with repressor OsJAZs instead of co-repressor TOPLESS to possibly realize its transcriptional repression function. Taken together, we concluded that two interacting TFs in rice, OsMYB1 and OsSPL14, played antagonistic roles in regulating resistance to BPH and Xoo.

Mechanism of Zhengsui Wan in the Treatment of Acute Lymphoblastic Leukemia Based on Network Pharmacology and Experimental Validation.

Zhengsui Wan (ZSW) is a commonly used traditional Chinese medicine formula for treating Acute Lymphatic Leukemia (ALL) in our institution, and it has shown potential efficacy. However, its mechanism of action (MoA) remains unclear. In this study, we systematically explored the ZSW in ALL (in vitro and in vivo) using network pharmacology and molecular docking techniques. Mass spectrometry was conducted to analyze possible active components in ZSW. BALB/c mice were treated by ZSW aqueous decoction, and mesenchymal stem cells (MSCs) were extracted for proteomic analysis to evaluate differentially expressed proteins. Moreover, proteins associated with acute lymphoblastic leukemia in SwissTargetPrediction and GeneCards databases were screened, and they intersected with differentially expressed proteins to obtain potential targets for ZSW. Protein interactions were constructed for the selected targets. Then, we performed GO and KEGG enrichment analysis on its basis and screened the core target through K-core. We validated it by molecular docking with the top three actives in the molecular network in degree value. Finally, we detected the regulation of ICAM1 in MSCs by ZSW by qRT-PCR. We detected 182 active ingredients in ZSW and identified 725 differential proteins in ZSWtreated mice, of which 25 were potential targets. Furthermore, MMP2, ICAM1, PSEN1, SLC9A1, and MMP14 were identified as core targets using the PPI network and K-core screening. Moreover, ZSW significantly downregulated ICAM1 expression in MSCs. GO and KEGG enrichment analyses showed that the results of ZSW were coordinated through immunomodulatory, inflammation-related, and drug resistance-related genes, including the PI3K-Akt, cAMP, and Wnt signaling pathways. Molecular docking and molecular dynamics simulations indicated moderate binding capacity between the active compounds and the screened target. In this study, we successfully identified possible active ingredients and predicted potential targets and pathways for ZSW for the treatment of ALL. We provide a new strategy for further research on the molecular basis of ZSW biological effects in ALL. In addition, the potential active ingredients could provide new leads for drug discovery in ALL investigations.

Antibiotic susceptibility testing and molecular characterization based on whole-genome sequencing of Streptococcus pneumoniae isolates from pediatric infections at the National Regional Medical Center of Southwest China during the COVID-19 pandemic

BackgroundStreptococcus pneumoniae is a transmitted respiratory pathogen that causes high morbidity and mortality in children, especially those under 5 years of age. During the implementation of population control measures for COVID-19 in mainland China, the Streptococcus pneumoniae detection rate in pediatric patients decreased. However, with the second wave of the COVID-19 pandemic (2022), the incidence of pneumococcal disease (PD) and even invasive pneumococcal disease (IPD) began to rise again.MethodsThis study was conducted from August 2022 to September 2023 at a national regional medical center based mainly in West China Second University Hospital, Sichuan University. The demographic and clinical characteristics of S. pneumoniae-infected pediatric patients were analyzed. All S. pneumoniae isolates were subjected to standardized clinical sample inoculation, culture, subculture, and identification procedures. Next-generation sequencing and analysis were used to determine serotypes and sequence types (STs) and evaluate antibiotic resistance- and virulence-related genes. Antimicrobial susceptibility was determined in AST dishes via the broth microdilution method.ResultsThe prevalent serotypes in the IPD patients were 14, 6A, and 23F, and the prevalent serotypes in the NIPD patients were 19F and 6A. A significant difference in the proportion of patients with serotype 14 was noted between the two groups. A total of 23 STs were identified and classified into 13 different GPSC lineages, including 4 novel STs (ST18449, ST18451, ST18464 and ST18466) and 1 novel allele (ddl1209). According to the interpretation breakpoints for non-meningitis infections, the resistance/nonsusceptibility rates of invasive isolates were as follows: penicillin (0.0%/8.3%), amoxicillin (0.0%/0.0%), cefotaxime (8.3%/16.6%), ceftriaxone (8.3%/8.3%), and cefepime (0.0%/8.3%). The resistance/nonsusceptibility rates of invasive isolates according to the meningitis breakpoints were as follows: penicillin (100.0%), cefotaxime (16.7%/33.4%), ceftriaxone (8.3%/50.0%), and cefepime (8.3%/66.7%). All the isolates were susceptible to rifampicin, levofloxacin, moxifloxacin, linezolid and vancomycin. In addition, the characteristics of the antibiotic resistance-related genes and virulence genes of serotype 19F were significantly different from those of the other serotypes.ConclusionThese data provide valuable information for understanding pediatric pneumococcal disease during the second outbreak of COVID-19 in Southwest China and will contribute to the prevention and treatment of S. pneumoniae infection.

Physiological characteristics and transcriptomic analyses of alfalfa root crown in wintering

BackgroundAlfalfa, scientifically identified as Medicago sativa, is repeatedly referred to as the “king of forages”. Because of its tight relationship to winter hardiness, the alfalfa’s root crown plays a significant role as a storage organ over the winter. At present, it is still unknown what molecular process makes the alfalfa root crown resistant to cold. This study was aimed to study these knowledge gaps. Using RNA sequencing (RNA-Seq) technology, significant genes associated with cold hardiness were found.MethodsAccording to the random block design, Longmu 806 alfalfa and Sardi alfalfa were planted in regional experiments. Under the condition of low-temperature treatment in winter, the differentially expressed genes (DEGs), winter survival rate (WSR), and physiological characteristics were, in turn, calculated by RNA-Seq, chemical analysis, and field investigation.ResultsThe WSR of the Longmu 806 alfalfa was 3.68-fold greater than that of the Sardi alfalfa. The jasmonic acid (JA), soluble sugar (SS), proline (Pro), and glutathione (GSH) concentration in the roots of Longmu 806 alfalfa was more than the same amount in Sardi alfalfa in other words P is less than 0.05. An entire set of 878 DEGs related to winter hardiness was found by statistical analysis. Among them, 463 DEGs showed an increase in expression, whereas 415 DEGs showed a decrease in expression. The metabolic pathways’ examination presented that the DEGs (MsERF1, MsCHIB, MsJAZ, MsAOC, MsGST, MsINV, MsTPS, and MsOAT) were linked to the pathways of “plant hormone signaling transduction”, “Amino sugar and nucleotide sugar metabolism”, and “glutathione metabolism”. Furthermore, the physiological changes in JA, SS, Pro content, and GSH were influenced by the dynamic transcription profile of LT (low- temperature) resistance-related genes.

RGIE: A Gene Selection Method Related to Radiotherapy Resistance in Head and Neck Squamous Cell Carcinoma.

Head and Neck Squamous Cell Carcinoma (HNSCC) is a malignant tumor with a high degree of malignancy, invasiveness, and metastasis rate. Radiotherapy, as an important adjuvant therapy for HNSCC, can reduce the postoperative recurrence rate and improve the survival rate. Identifying the genes related to HNSCC radiotherapy resistance (HNSCC-RR) is helpful in the search for potential therapeutic targets. However, identifying radiotherapy resistance-related genes from tens of thousands of genes is a challenging task. While interactions between genes are important for elucidating complex biological processes, the large number of genes makes the computation of gene interactions infeasible. We propose a gene selection algorithm, RGIE, which is based on ReliefF, Gene Network Inference with Ensemble of Trees (GENIE3) and Feature Elimination. ReliefF was used to select a feature subset that is discriminative for HNSCC-RR, GENIE3 constructed a gene regulatory network based on this subset to analyze the regulatory relationship among genes, and feature elimination was used to remove redundant and noisy features. Nine genes (SPAG1, FIGN, NUBPL, CHMP5, TCF7L2, COQ10B, BSDC1, ZFPM1, GRPEL1) were identified and used to identify HNSCC-RR, which achieved performances of 0.9730, 0.9679, 0.9767, and 0.9885 in terms of accuracy, precision, recall, and AUC, respectively. Finally, qRT-PCR validated the differential expression of the nine signature genes in cell lines (SCC9, SCC9-RR). RGIE is effective in screening genes related to HNSCC-RR. This approach may help guide clinical treatment modalities for patients and develop potential treatments.

Analysis of Mutations in Pneumocystis jirovecii Dihydropteroate Synthase and Dihydropteroate Reductase Genes Among Non-HIV Patients in China.

Pneumocystis jirovecii pneumonia (PJP) shows a high fatality rate in non-HIV patients. However, there are limited data on P. jirovecii drug resistance-related gene mutations in these patients. This study aimed to describe the prevalence of mutations in the dihydrofolate reductase (DHFR) and dihydropteroate synthase (DHPS) genes of P. jirovecii in non-HIV patients in China, providing a reference for drug usage. We analyzed the polymorphisms of DHPS and DHFR genes from 45 non-HIV patients in China, including P. jirovecii infection (n = 14) and P. jirovecii colonization (n = 31). This analysis also considered clinical characteristics, P. jirovecii burden, treatment response, and prognosis. Compared to the P. jirovecii colonization, P. jirovecii infection had significantly altered blood indicators (GR%, LY%, HGB, TP, ALB, CRP, P<0.05) with higher P. jirovecii burden (P<0.05) and worse prognosis (P<0.05). Additionally, patients with P. jirovecii infection were more susceptible to infections, such as the Epstein-Barr virus, Cytomegalovirus, Mycoplasma and Klebsiella pneumoniae. Although no known drug-resistance mutations were detected in the DHPS gene in this study, 10 nonsynonymous mutations were identified. Furthermore, 10 nonsynonymous and 2 synonymous mutations were found in the DHFR gene. However, these mutations were not associated with a worse prognosis. Our results implied that TMP-SMX prophylaxis is still recommended for PJP in high-risk non-HIV patients in China.

Whole genome sequencing and analysis of a goose-derived Mycoplasma gallisepticum in Guangdong Province, China.

Mycoplasma gallisepticum (MG) infection is a primary cause of chronic respiratory disease in poultry, threatening the economic viability of China's goose-farming industry. This study investigated the pathogenicity and drug resistance of an MG strain isolated from geese and whole-genome sequenced the strain. A strain designated MG-GD01/22 was isolated from the air-sac tissues of five geese with chronic respiratory disease on a Guangdong goose farm. Its pathogenicity was assessed, antimicrobial susceptibility tests were performed using agar dilution, and its total DNA was extracted for whole-genome sequencing and gene function annotation with second- and third-generation sequencing technologies. The homology of the 16S ribosomal RNA (rRNA) region was analysed and a phylogenetic tree was constructed, as was an evolutionary tree of the mgc2 gene. Gene co-linearity analysis was performed to compare MG-GD01/22 with the strains in the GenBank database. The isolate produced "fried egg" colonies and was pathogenic to goslings. It was resistant to enrofloxacin, danofloxacin and spectinomycin and susceptible to valnemulin, tilmicosin, tylosin, acetylisovaleryltylosin tartrate and tiamulin. The genome analysis revealed 1,666 coding genes. Gene database annotation identified 25 virulence-related genes, 22 drug resistance-related genes, 13 pathogen-host-interaction genes and 9 carbohydrate-active enzyme genes. The isolate exhibited 99.9% homology to the MG S6 strain by its 16S rRNA, while the mgc2 gene typing results indicated that it differed from known MG model strains. The genome of MG-GD01/22 showed high homology but poor co-linearity with MG S6, characterised by numerous gene deletions, inversions and displacements. This study offers theoretical references for the diagnosis, prevention and treatment of MG in geese in the Guangdong region.

Physiological and molecular mechanisms of leaf response to high-temperature stress in high-temperature-resistant soybean varieties

BackgroundWith increasing global limate warm, high temperature (HT) is one of limiting factors for soybean yield and quality. Exploring HT resistance-related functional genes and their corresponding molecular mechanisms is of great value. In our previous report, compared with HD14 (HT sensitive), JD21 is an HT-resistant variety, and further analysis of the transcriptome and proteome has revealed the HT tolerance mechanism of JD21 anthers. We found that compared with those of HD14 (28.72%), the leaves of JD21 also exhibited HT resistance, and the degree of leaf wilting in JD21 plants after HT stress treatment was 11.02%; however, the regulatory mechanism of the response of JD21 to HT stress is still unclear.ResultsIn this study, comparative transcriptome analysis of JD21 and HD14 soybean leaves after HT stress and field control plants was performed by RNA-seq analysis. The results showed that the number of upregulated differentially expressed genes (DEGs) in JD21 and HD14 was greater than the number of downregulated DEGs after HT stress, and the number of up- or down-regulated DEGs in JD21 was higher than those of HD14. Bioinformatics analysis revealed that many DEGs were involved in various molecular functions and metabolic pathways. QRT‒PCR analysis verified that the gene expression pattern results determined via RNA–seq was reliable. In addition, through analysis of gene expression level and conserved domain, 18 key candidate genes related to the response of soybean leaves to HT stress were screened.ConclusionsThis study systematically revealed the regulation mechanism of soybean leaves molecular transcription level by RNA-seq, and several key candidate DEGs (transcription factor, HSPs, HSFs, GmCYP78A6, etc.) involved in the response to HT stress were identified based on the bioinformatics analysis. The results provided a theoretical basis for studying the response mechanism of soybean leaves to HT stress.

Unveiling the therapeutic potential of anthocyanin/cisplatin-loaded chitosan nanoparticles against breast and liver cancers

BackgroundLiver and breast cancers are among the leading causes of cancer-related deaths worldwide, prompting researchers to seek natural anticancer agents and reduce chemotherapy side effects. Red beetroot (Beta vulgaris Linnaeus), rich in polyphenols and powerful antioxidants, has shown potential in cancer prevention. This study aimed to evaluate the impact of red beetroot-derived anthocyanin (Ant), Ant-loaded chitosan nanoparticles (Ant NPs), cisplatin (Cis), Cis-loaded chitosan (Cis NPs), and Cis + Ant-loaded chitosan NPs on human hepatoma HepG2 and breast adenocarcinoma MCF7 cell lines.MethodsNPs preparation was evaluated by zeta potential, FTIR, and SEM. The cytotoxic, apoptotic, antioxidant, anti-inflammatory, anti-metastatic, and anti-angiogenic effects were assessed by MTT assay, qPCR, AO/EB staining, and flow cytometry.ResultsTreatment with Ant, Ant NPs, Cis, Cis NPs, and Cis + Ant NPs caused cytotoxicity in HepG2 and MCF7 with best effect in Cis-treated cells. The anticancer effects were attributed to mitochondrial-dependent apoptosis (with high Bax and low Bcl2 expression), chromatin disintegration, and cell cycle arrest in G2/M and S phases. All treatments inhibited migration by downregulating the migration-related gene MMP9 and upregulating the anti-migratory gene TIMP1 and decreased the angiogenesis-related gene VEGF and the inflammatory gene TNFα with best results in Cis NPs-treated cells. Interestingly, Ant, Ant NPs, and Cis + Ant NPs increased the antioxidant status (high GSH and upregulated expression of Nrf2 and OH-1) and decreased drug resistance-related MAPK1 and MDR1 genes compared to Cis and Cis NPs-treated cells.ConclusionsAnthocyanin and cisplatin-loaded chitosan nanoparticles effectively combat breast and liver cancers by inducing cancer cell apoptosis, enhancing antioxidant defenses, and reducing inflammation. They also inhibit tumor spread and blood vessel formation through downregulation of MMP9 and VEGF, highlighting their therapeutic potential.

Genomic characterisation of an extended-spectrum β-Lactamase-producing Klebsiella pneumoniae isolate assigned to a novel sequence type (6914)

BackgroundCow milk, which is sometimes consumed raw, hosts a plethora of microorganisms, some of which are beneficial, while others raise food safety concerns. In this study, the draft genome of an extended-spectrum β-lactamase-producing Klebsiella pneumoniae subsp. pneumoniae strain Cow102, isolated from raw cow milk used to produce traditional foods in Nigeria, is reported.ResultThe genome has a total length of 5,359,907 bp, with 70 contigs and a GC content of 57.35%. A total of 5,244 protein coding sequences were detected with 31% mapped to a subsystem, and genes coding for amino acids and derivatives being the most prevalent. Multilocus sequence typing revealed that the strain had new allelic profile assigned to the novel 6914 sequence type possessing capsular and lipopolysaccharide antigen K locus 122 with an unknown K type (KL122) and O locus O1/O2v2 with type O2afg, respectively. A total of 28 resistance-related genes, 98 virulence-related genes, two plasmids and five phages were identified in the genome. The resistance genes oqxA, oqxB and an IS3 belonging to cluster 204 were traced to bacteriophage Escher 500,465. Comparative analysis predicted one strain specific orthologous group comprising three genes.ConclusionThis report of a novel sequence type (ST6914) in K. pneumoniae presents a new allelic profile, indicating ongoing evolution and diversification within the species. Its uniqueness suggests it may represent a locally evolved lineage, although further sampling would be necessary to confirm this hypothesis. The strain’s multidrug resistance, virulence gene repertoire, and isolation from animal milk render it a potentially significant public health concern, underscoring the importance of genomic surveillance in non-clinical settings to detect emerging strains. Further research is required to fully characterise the capsular K type of ST6914.

Isolation and Characterization of a Novel Escherichia Bacteriophage with Potential to Control Multidrug-Resistant Avian Pathogenic Escherichia coli and Biofilms.

Background/Objectives: Avian pathogenic Escherichia coli (APEC) infection is a significant problem for the global chicken industry, as it decreases animal welfare and is associated with substantial economic losses. Traditionally, APEC infections have been controlled through the use of antibiotics, which has led to an increased prevalence of antibiotic-resistant E. coli. Therefore, developing alternative treatments for APEC infection is crucial. Methods: In this study, an Escherichia phage specific to multidrug-resistant (MDR) APEC, designated as phage vB_EcoP_PW8 (phage vECPW8), was isolated. The morphology, phage adsorption to host cells, one-step growth curve, thermal stability, pH stability, whole-genome sequencing, antibacterial ability, and antibiofilm efficacy of phage vECPW8 were evaluated. Results: The results demonstrated that phage vECPW8 has a Podoviridae morphology and is effective at lysing bacteria. Phage vECPW8 exhibited a high absorption rate to bacterial cells (more than 85% within 10 min) and had a latent period of 20 min, with a burst size of 143 plaque-forming units per cell. Additionally, phage vECPW8 showed good temperature and pH stability. The phage displayed strong antibacterial activity in vitro, and its efficacy in controlling bacteria was confirmed through scanning electron microscopy. Whole-genome sequencing revealed that the phage has a linear genome with 69,579 base pairs. The genome analysis supported the safety of the phage, as no toxin, virulence, or resistance-related genes were detected. Phage vECPW8 was identified as a novel lytic phage in the Gamaleyavirus genus and Schitoviridae family. The phage also demonstrated antibiofilm efficacy by reducing and preventing biofilm formation, as evidenced by biofilm biomass and bacterial cell viability measurements. Conclusions: These results indicate that phage vECPW8 is a promising candidate for the effective treatment of MDR APEC infections in poultry.

Comparative metabolome and transcriptome analyses reveal the role of MeJA in improving postharvest disease resistance and maintaining the quality of Rosa roxburghii fruit

Rosa roxburghii has a short and concentrated harvest period, during which rapid decay and quality deterioration at room temperature pose significant challenges to the supply chain. To address this, we applied methyl jasmonate (MeJA) treatment and stored the fruit at low temperatures. MeJA treatment effectively reduced decay, maintained fruit firmness and brightness, suppressed respiration, and decreased malondialdehyde content. Further analysis revealed that MeJA reduced hydrogen peroxide levels by boosting the activities and gene expressions of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Additionally, MeJA upregulated the expression of disease resistance-related genes (RrRGA3, RrPPO, RrCHIT, RrPRB1, and RrRPM1). It also stimulated genes involved in the AsA synthesis and AsA-GSH cycle (RrMIXO, RrAKRC9, RrDHAR, and RrGPX), thereby increasing AsA content. Moreover, MeJA promoted the activities (PAL, C4H, and 4CL) and gene expressions (RrPAL, Rr4CL, RrCSE, RrCCR, RrPGT, RrHCT, RrDFR and RrERF114) of phenylpropane metabolism, resulting in increased levels of L-phenylalanine, caffeic acid, phlorizin, and other phenolic acids and lignin content. Furthermore, MeJA induced the expression of genes related to JA biosynthesis (RrAOC, RrOPR, and RrACX), and abscisic acid synthesis (RrNCED). In conclusion, these findings suggest that MeJA treatment enhances disease resistance and preserves the postharvest quality of R. roxburghii, making it a promising preservation method for large-scale commercial application in fruit storage.

Genome-wide analysis of the HSF family in Allium sativum L. and AsHSFB1 overexpression in Arabidopsis under heat stress

The heat shock transcription factor (HSF) family is one of the most widely studied transcription factor families in plants; HSFs can participate in the response to various stressors, such as heat stress, high salt, and drought stress. Based on garlic transcriptome data, we screened and identified 22 garlic HSFs. The HSF proteins of garlic and Arabidopsis can be divided into three (A, B, C) subfamilies. The phylogenetic relationship, chromosome localization, sequence characteristics, conserved motifs, and promoter analysis of the HSF family were analyzed through bioinformatics methods. RT-qPCR analysis showed that the nine selected genes had different degrees of response to heat stress. In addition, we isolated and identified a class B HSF gene, AsHSFB1, from garlic variety ‘Xusuan No.6’. Subsequently, the AsHSFB1 gene was overexpressed in Arabidopsis thaliana. Under heat stress, the germination rate and growth of wild-type plants were better than that of transgenic plants. Moreover, after heat treatment, the contents of peroxidase, catalase, and chlorophyll a and b of transgenic plants were lower, but the contents of malondialdehyde (MDA) and leaf conductivity were higher. Nitroblue tetrazolium (NBT) staining showed that the stained area of transgenic plant leaves was larger than that of the wild type. Further studies showed that AsHSFB1 overexpression inhibited the expression of related reverse resistance genes. These results indicate that AsHSFB1 might play a negative regulatory role in garlic resistance under high stress. Altogether, these findings provide valuable data for revealing the function of HSF genes and lay a foundation for the subsequent selection of heat-resistant garlic varieties.

Novel SNPs Linked to Blast Resistance Genes Identified in Pearl Millet Through Genome-Wide Association Models.

Foliar blast, caused by Pyricularia grisea, poses a major challenge to pearl millet (Pennisetum glaucum (L.) R. Br) production, leading to severe yield losses, particularly in rainfed ecologies. This study aimed to elucidate the genetic basis of blast resistance through a genome-wide association study (GWAS) involving 281 diverse pearl millet inbreds. GWAS panel was phenotyped for blast resistance against three distinct isolates of P. grisea collected from Delhi, Gujarat, and Rajasthan locations, revealing a significant variability with 16.7% of the inbreds showing high resistance. Bayesian information and linkage disequilibrium iteratively nested keyway (BLINK) and Multi-Locus Mixed Model (MLMM) models using transformed means identified 68 significant SNPs linked to resistance, with hotspots for resistance-related genes on chromosomes 1, 2, and 6. These regions harbor genes involved in defense mechanisms, including immune response, stress tolerance, signal transduction, transcription regulation, and pathogen defense. Genes, namely 14-3-3-like proteins RGA2, RGA4, hypersensitive-induced response proteins, NHL3, NBS-LRR, LRR-RLK, LRRNT_2, and various transcription factors such as AP2/ERF and WRKY, played a crucial role in the stress-responsive pathways. Analyses of transporter proteins, redox processes, and structural proteins revealed additional mechanisms contributing to blast resistance. This study offers valuable insights into the complex genetic architecture of blast resistance in pearl millet, offering a solid foundation for marker-assisted breeding programs and gene-editing experiments.

Whole-genome analysis of stress resistance-related genes in Listeria monocytogenes

Listeria monocytogenes is a crucial foodborne pathogen with significant public health implications. This study analyzed whole-genome sequences (WGS) of L. monocytogenes strains from public databases, examining associations between resistance genes, lineage, strain type, isolation source, and geography. Results revealed that after eliminating duplicates and strains with incomplete WGS, a total of 316 strains were deemed suitable for subsequent analyses. Within these strains, lineages I and II were extensively distributed, predominantly isolated from clinical and food sources. 56.65% of these strains fell into seven major Clonal Complexes (CC), identified by Multilocus Sequence Typing (MLST), correlating significantly with isolation information. Analysis of 46 resistance-related genes showed a high consistency of resistance genes in the same type of strains, hinting at a potential causal chain of ‘food-food environment-evolution of L. monocytogenes’. Moreover, the standard strains exhibit similar gene carriage rates as the sample strains, with multiple variations observed in acid-resistance genes. In conclusion, through a comprehensive analysis of the L. monocytogenes genome sequences, this study deepens our understanding of the differences and associations between its lineage, strain typing, isolation sources, geographical distribution, and resistance genes, thereby providing a scientific basis for formulating more effective prevention and control strategies.

Surface-functionalized UIO-66-NH2 for dual-drug delivery of vancomycin and amikacin against vancomycin-resistant Staphylococcus aureus

BackgroundConventional antibacterial compounds can inhibit the growth of microorganisms, but their adverse effects and the development of drug limit their widespread use. The current study aimed to synthesize PEG-coated UIO-66-NH2 nanoparticles loaded with vancomycin and amikacin (VAN/AMK-UIO-66-NH2@PEG) and evaluate their antibacterial and anti-biofilm activities against vancomycin-resistant Staphylococcus aureus (VRSA) clinical isolates.MethodsThe VAN/AMK-UIO-66-NH2@PEG were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) to determine their size, polydispersity index (PDI), encapsulation efficiency (EE%), zeta-potential, drug release profile, and physical stability. Antibacterial activity was evaluated using minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill assays. Biofilm formation by VRSA was assessed using the crystal violet (CV) and minimum biofilm eradication concentration (MBEC) assays. The effect of sub-MIC concentrations of the formulations on the expression of biofilm-related genes (icaA, icaD) and resistance-related genes (mecA, vanA) was investigated using quantitative real-time polymerase chain reaction (RT-qPCR).ResultsAs demonstrated by MIC, MBC and time-kill assay, the VAN/AMK-UIO-66-NH2@PEG nanoparticles exhibited enhanced antibacterial activity against VRSA isolates compared to free drugs and prepared formulations. Furthermore, CV and MBEC tests indicated that the VAN/AMK-UIO-66@NH2/PEG can reduce biofilm formation dramatically compared to VAN/AMK and VAN/AMK-UIO-66@NH2, due to its great drug release properties. This study also found that the expression level of the mecA, vanA, icaA, and icaD genes in VAN/AMK-UIO-66@NH2/PEG treated VRSA isolates was substantially decreased compared to other groups.ConclusionsThese findings highlighted the efficiency of VAN/AMK-UIO-66@NH2/PEG in combating antimicrobial resistance and biofilm formation in VRSA isolates. Future studies, particularly in vivo models, are necessary to evaluate the safety, efficacy, and clinical applicability of these nanoparticles for the treatment of bacterial infections.

Identification and characterization of a novel Haematococcus pluvialis strain resistant to Paraphysoderma sedebokerense infection

The commercial culture of Haematococcus pluvialis is threatened by the pathogen Paraphysoderma sedebokerense, leading to substantial losses in the natural astaxanthin industry. This study successfully identified a novel H. pluvialis strain WBG-26, which exhibited high resistance to P. sedebokerense in both laboratory and open raceway ponds. Comparative analysis showed that the resistant strain WBG-26 had a thicker cell wall and lower levels of specific monosaccharides which may be closely related to resistance. RNA-sequencing analysis revealed differential gene expression profiles, with 29 up-regulated and 25 down-regulated genes identified as crucial for resistance. Using bioinformatics analysis, we identified several potential resistance genes and resistance-related genes, such as those encoding receptor-like kinases, leucine-rich repeat, transcription factors, CAZymes, and heat shock proteins, which may play critical roles in defense response. This study represents a comprehensive investigation of multiple defense mechanisms of microalgae, providing insights into breeding disease-resistant microalgal strains for biotechnological applications.

Genetic Insights on Meropenem Resistance Concerning Klebsiella pneumoniae Clinical Isolates.

The transferable genetic elements are associated with the dissemination of virulence determinants amongst Klebsiella pneumoniae. Thus, we assessed the correlated antimicrobial resistance in carbapenem-resistant Klebsiella pneumoniae clinical isolates. Each isolate's ability to biosynthesize biofilm, carbapenemase, and extended-spectrum β-lactamase were examined. Genotypically, the biofilm-, outer membrane porin-, and some plasmid-correlated antimicrobial resistance genes were screened. About 50% of the isolates were multidrug-resistant while 98.4% were extended-spectrum β-lactamase producers and 89.3% were carbapenem-resistant. Unfortunately, 93.1% of the multidrug-resistant isolates produced different biofilm levels. Additionally, fimD and mrkD genes encoding adhesins were detected in 100% and 55.2% of the tested isolates, respectively. Also, the blaKPC, blaOXA-48-like, and blaNDM-encoding carbapenemases were observed in 16.1%, 53.6%, and 55.4% of the tested isolates, respectively. Moreover, the blaSHV and blaCTX-M extended-spectrum β-lactamase-associated genes were detected at 95.2% and 61.3%, respectively. Furthermore, aac(3)IIa, qnrB, and tetB resistance-correlated genes were observed in 38.1%, 46%, and 7.9% of the tested isolates, respectively. Certainly, the tested antimicrobial resistance-encoding genes were concurrently observed in 3.2% of the tested isolates. These findings confirmed the elevated prevalence of various antimicrobial resistance-associated genes in Klebsiella pneumoniae. The concurrent transferring of plasmid-encoding antimicrobial resistance-related genes could be associated with the possible acquisition of multidrug-resistant Klebsiella pneumoniae phenotypes.