Ferulic Acid Inhibits Arsenic-Induced Colon Injury by Improving Intestinal Barrier Function.

The prolonged exposure to arsenic results in intestinal barrier dysfunction, which is strongly concerned with detrimental processes such as oxidative stress and the inflammatory response. Ferulic acid (FA), as a phenolic acid, possesses the capability to mitigate arsenic-induced liver damage and cardiotoxic effects dependent on inhibition of oxidative stress and inflammatory responses. FA can mitigate testicular tissue damage and alveolar epithelial dysfunction, the mechanism of which may rely on nuclear factor erythroid 2-related factor 2/heme oxygenase 1 (Nrf2/HO-1) activation and nuclear factor-kappa B (NF-κB) pathway blocking. Based on the antioxidant and anti-inflammatory properties of FA, we speculated that FA might have the potential to inhibit arsenic-induced intestinal damage. To confirm this scientific hypothesis, mice exposed to sodium arsenite were treated with FA to observe colonic histopathology and TJ protein levels, and oxidative stress and TJ protein levels in Caco-2 cells exposed to sodium arsenite were assessed after FA intervention. In addition, molecular levels of NF-κB and Nrf2/HO-1 pathway in colon and Caco-2 cells were also detected. As shown in our data, FA inhibited arsenic-induced colon injury, which was reflected in the improvement of mucosal integrity, the decrease of down-regulated expression of tight junction (TJ) proteins (Claudin-1, Occludin, and ZO-1) and the inhibition of oxidative stress. Similarly, treatment with FA attenuated the inhibitory effect of arsenic on TJ protein expression in Caco-2 cells. In addition to suppressing the activation of NF-κB pathway, FA retrieved the activation of Nrf2/HO-1 pathway in colon and intestinal epithelial cells induced by arsenic. In summary, our findings propose that FA has the potential to mitigate arsenic-induced intestinal damage by preserving the integrity of intestinal epithelial TJs and suppressing oxidative stress. These results lay the groundwork for the potential use of FA in treating colon injuries caused by arsenic.

Discovery and characterization of a novel pathogen Erwinia pyri sp. nov. associated with pear dieback: taxonomic insights and genomic analysis.

In 2022, a novel disease similar to pear fire blight was found in a pear orchard in Zhangye City, Gansu Province, China. The disease mainly damages the branches, leaves, and fruits of the plant. To identify the pathogen, tissue isolation and pathogenicity testing (inoculating the potential pathogen on healthy plant tissues) were conducted. Furthermore, a comprehensive analysis encompassing the pathogen's morphological, physiological, and biochemical characteristics and whole-genome sequencing was conducted. The results showed that among the eight isolates, the symptoms on the detached leaves and fruits inoculated with isolate DE2 were identical to those observed in the field. Verifying Koch's postulates confirmed that DE2 was the pathogenic bacterium that causes the disease. Based on a 16S rRNA phylogenetic tree, isolate DE2 belongs to the genus Erwinia. Biolog and API 20E results also indicated that isolate DE2 is an undescribed species of Erwinia. Isolate DE2 was negative for oxidase. Subsequently, the complete genome sequence of isolate DE2 was determined and compared to the complete genome sequences of 29 other Erwinia species based on digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) analyses. The ANI and dDDH values between strain DE2 and Erwinia species were both below the species thresholds (ANI < 95-96%, dDDH<70%), suggesting that isolate DE2 is a new species of Erwinia. We will temporarily name strain DE2 as Erwinia pyri sp. nov. There were 548 predicted virulence factors in the genome of strain DE2, comprising 534 on the chromosome and 5 in the plasmids. The whole genome sequence of strain DE2 has been submitted to the NCBI database (ASM3075845v1) with accession number GCA_030758455.1. The strain DE2 has been preserved at the China Center for Type Culture Collection (CCTCC) under the deposit number CCTCC AB 2024080. This study represents the initial report of a potentially new bacterial species in the genus Erwinia that causes a novel pear dieback disease. The findings provide a valuable strain resource for the study of the genus Erwinia and establish a robust theoretical foundation for the prevention and control of emerging pear dieback diseases.

Diversity and Antibiotic Resistance of Triticale Seed-Borne Bacteria on the Tibetan Plateau.

The Tibetan Plateau is located in southwestern China. It has many important ecological functions, such as biodiversity protection, and is an important grassland agroecosystem in China. With the development of modern agriculture and animal husbandry, antibiotics are widely used to treat humans and livestock, and antibiotics cannot be fully metabolised by both. Antibiotics eventually find their way into the environment, affecting other parts of grassland agroecosystems. Triticale (Triticosecale wittmack) is an artificial hybrid forage that can be used for both grain and forage. This study revealed the diversity of seedborne bacteria in triticale on the Tibetan Plateau and the resistance of the bacteria to nine antibiotics. It identified 37 representative strains and successfully obtained the spliced sequences of 36 strains of the bacteria, which were clustered into 5 phyla and 16 genera. Among them, 18 strains showed resistance to at least one of the 9 antibiotics, and the colony-forming unit (CFU) abundance of antibiotic-resistant bacteria (ARB) accounted for 45.38% of the total samples. Finally, the bacterial motility and biofilm formation ability were measured, and their correlation with bacterial resistance was analysed. The results showed that the bacterial resistance did not have an absolute positive correlation with the motility or biofilm formation ability.

Seed-Borne Bacterial Diversity of Fescue (Festuca ovina L.) and Properties Study.

Rich endophytic bacterial communities exist in fescue (Festuca ovina L.) and play an important role in fescue growth, cold tolerance, drought tolerance and antibiotic tolerance. To screen for probiotics carried by fescue seeds, seven varieties were collected from three different regions of China for isolation by the milled seed method and analyzed for diversity and motility, biofilm and antibiotic resistance. A total of 91 bacterial isolates were obtained, and based on morphological characteristics, 36 representative dominant strains were selected for 16S rDNA sequencing analysis. The results showed that the 36 bacterial strains belonged to four phyla and nine genera. The Firmicutes was the dominant phylum, and Bacillus, Paenibacillus and Pseudomonas were the dominant genera. Most of the strains had motility (80%) and were biofilm-forming (91.7%). In this study, 15 strains were capable of Indole-3-acetic acid (IAA) production, 24 strains were capable of nitrogen fixation, and some strains possessed amylase and protease activities, suggesting their potential for growth promotion. Determination of the minimum inhibitory concentration (MIC) against the bacteria showed that the strains were not resistant to tetracycline and oxytetracycline. Pantoea (QY6, LH4, MS2) and Curtobacterium (YY4) showed resistance to five antibiotics (ampicillin, kanamycin, erythromycin, sulfadiazine and rifampicin). Using Pearson correlation analysis, a significant correlation was found between motility and biofilm, and between biofilm and sulfadiazine. In this study, we screened two strains of Pantoea (QY6, LH4) with excellent growth-promoting ability as well as broad-spectrum antibiotic resistance. which provided new perspectives for subsequent studies on the strong ecological adaptations of fescue, and mycorrhizal resources for endophytic bacteria and plant interactions.

Diversity and Biological Characteristics of Seed-Borne Bacteria of Achnatherum splendens.

As a high-quality plant resource for ecological restoration, Achnatherum splendens has strong adaptability and wide distribution. It is a constructive species of alkaline grassland in Northwest China. The close relationship between seed-borne bacteria and seeds causes a specific co-evolutionary effect which can enhance the tolerance of plants under various stresses. In this study, 272 bacterial isolates were isolated from the seeds of Achnatherum splendens in 6 different provinces of China. In total, 41 dominant strains were identified, and their motility, biofilm formation ability and antibiotic resistance were analyzed. The results showed that the bacteria of Achnatherum splendens belonged to 3 phyla and 14 genera, of which Firmicutes was the dominant phylum and Bacillus was the dominant genus. The motility and biofilm formation ability of the isolated strains were studied. It was found that there were six strains with a moving diameter greater than 8 cm. There were 16 strains with strong biofilm formation ability, among which Bacillus with biofilm formation ability was the most common, accounting for 37.5%. The analysis of antibiotic resistance showed that sulfonamides had stronger antibacterial ability to strains. Correlation analysis showed that the resistance of strains to aminoglycosides (kanamycin, amikacin, and gentamicin) was significantly positively correlated with their biofilm formation ability. This study provides fungal resources for improving the tolerance of plants under different stresses. In addition, this is the first report on the biological characteristics of bacteria in Achnatherum splendens.

Study on seed-borne cultivable bacterial diversity and antibiotic resistance of Poa pratensis L.

In order to study the difference of cultivable seed-borne bacterial diversity between commercial varieties and wild species of Poa pratensis L., and their antibiotic resistance to sulfadiazine, tetracycline, oxytetracycline, ciprofloxacin, gentamicin, oxytetracycline and rifampin. In this study, 60 bacterium isolates were isolated by dilution-coated plate method. Through 16S rRNA sequence analysis, 40 representative isolates with different morphological characteristics were identified and phylogenetic tree was constructed. The results of diversity analysis showed that the seed-borne bacterial diversity of commercial varieties was richer than that of wild species. The antibiotic resistance of the isolated bacterial strains was studied by agar dilution method, and it was concluded that the antibiotic resistance of the seed-borne bacteria carried by commercial varieties was stronger than that of the wild species. Finally, the biofilm formation ability and swimming motility of the bacterial strain were measured, and the correlation between the two and the antibiotic resistance of the bacterial strain was analyzed. The analysis showed that the antibiotic resistance of bacterial strains in Poa pratensis L. was significantly correlated with their swimming motility. In addition, the swimming motility of the bacterial strains was significantly correlated with the biofilm formation ability. It is worth mentioning that this is the first time to study the drug-resistant bacteria distributed in the seed-borne bacteria of Poa pratensis L.

The determination of the biological function of bacterial pink pigment and Fusarium chlamydosporum on alfalfa (Medicago sativa L.).

Bacterial pigment is one of the secondary metabolites produced by bacteria and has functions that are yet to be understood in relation to soil-borne pathogenic fungi and plants in mutualistic processes. The study evaluates the growth, photosynthetic, and physiological characteristics of alfalfa after interacting with different concentrations of Cp2 pink pigment and Fusarium chlamydosporum. The findings showed that Cp2 pink pigment has the ability to inhibit the growth of alfalfa, with the inhibition ratio gradually increasing with rising concentration. F. chlamydosporum inhibited the growth of alfalfa, which reduced the photosynthetic physiological response and elevated antioxidant enzymes, which are typically manifested by yellowing leaves and shortened roots. Under the combined effect of Cp2 pink pigment and F. chlamydosporum, increasing concentrations of Cp2 pink pigment intensified the symptoms in alfalfa and led to more pronounced growth and physiological response. This indicates that the Cp2 pink pigment is one of the potential virulence factors secreted by the Erwinia persicina strain Cp2, which plays an inhibitory role in the interactions between F. chlamydosporum and alfalfa, and also has the potential to be developed into a plant immunomodulator agent.

SAA1 exacerbates pancreatic ß-cell dysfunction through activation of NF-κB signaling in high-fat diet-induced type 2 diabetes mice.

Insufficient decompensated insulin secretion and insulin resistance caused by pancreatic ß-cell dysfunction are the pathological bases of type 2 diabetes mellitus (T2DM). Glucolipotoxicity in pancreatic ß-cells is an important factor leading to their dysfunction, closely related to inflammatory signals, oxidative stress, mitochondrial dysfunction, and endoplasmic reticulum stress (ERs). However, there may be other unproven regulatory mechanisms that govern pancreatic ß-cell dysfunction. Therefore, further elucidation of the underlying mechanisms that lead to pancreatic ß-cells dysfunction will provide a sufficient theoretical basis for the more effective prevention and treatment of T2DM. As a stress protein with pro-inflammatory properties, Serum Amyloid 1 (SAA1) promotes the progression of metabolic syndrome-related diseases by activating immune cells and damaging endothelial cells. In the development of T2DM, the activation of nuclear factor-kappa B (NF-κB) signaling aggravates pancreatic ß-cells dysfunction under the stimulation of free fatty acids (FFAs), inflammatory factors, and chemokines. Moreover, the facilitating effect of SAA1 on the activation of the NF-κB signaling pathway has been demonstrated in other studies. In the present study, we demonstrated that SAA1 inhibits insulin secretion and promotes apoptotic molecular expression in pancreatic cells and islets and that NF-κB signaling inhibitors could reduce this effect of SAA1. SAA1 deficiency improved high-fat diet (HFD)-induced pancreatic ß-cell dysfunction and decreased expression of NF-κB signaling molecules. Our findings suggested that HFD-induced SAA1 might exacerbate T2DM by enhancing pancreatic ß-cell dysfunction; such a function of SAA1 might depend on NF-κB signaling activation.

Diverse Virulence Attributes of Pantoea alfalfae sp. nov. CQ10 Responsible for Bacterial Leaf Blight in Alfalfa Revealed by Genomic Analysis.

Alfalfa is widely grown worldwide for its excellent nutritional value. Pantoea species living in alfalfa seeds can easily spread over great distances with frequent trade. However, the pathogenic properties of this dangerous hitchhiker on alfalfa have not been evaluated. Here, we identified the taxonomic status of Pantoea strain CQ10 isolated from the interior of alfalfa seeds based on the whole genome sequence. The diverse virulence attributes of strain CQ10 during host infection were characterized through pathogenicity assays and functional and genomic analyses. We report that strain CQ10 belongs to a novel species in the genus Pantoea, which was phylogenetically close to Pantoea vagans and Pantoea agglomerans. Strain CQ10 caused bacterial leaf blight of alfalfa after inoculation from the roots. We found that strain CQ10 possesses a large number of pathogenic genes involved in shaping the virulence properties during bacteria-host interactions, including motility, biofilm, type VI secretion system, and nutrient acquisition. Compared with P. vagans and P. agglomerans, the unique virulence factors of strain CQ10 were mainly involved in motility and biofilm, which were confirmed by in vitro experiments. Taken together, our results suggest that strain CQ10 is the first Pantoea species to infect alfalfa, and it possesses diverse virulence attributes among which motility and biofilm may be the best weapons.

Seed-Borne Erwinia persicina Affects the Growth and Physiology of Alfalfa (Medicago sativa L.).

Seed-borne Erwinia persicina can be transmitted globally via alfalfa (Medicago sativa L.) seed trade, but there is limited information about the impact of this plant-pathogenic bacterium on alfalfa plants. In this study, strain Cp2, isolated from alfalfa seeds, was confirmed by whole-genome sequencing to belong to E. persicina. Subsequently, the effects of Cp2 on alfalfa growth and physiology were evaluated by constructing a rhizosphere infection model. Strain Cp2 had a strong inhibitory effect on the elongation and growth of alfalfa roots, which was very unfavorable to these perennial plants. Furthermore, an increased number of leaf spots and yellowing symptoms were observed in plants of the Cp2 group from day 10 to day 21 and the strain Cp2 was re-isolated from these leaves. Correlation between growth and photosynthetic parameters was analyzed and the significant decreases in fresh weight and root and plant lengths in the Cp2 group were related to the marked reduction of chlorophyll b, carotenoid, transpiration rate, and stomatal conductance of leaves (r > 0.75). In addition, nine physiological indicators of root, stem, and leaf were measured in the plants 21 days after treatment with Cp2. The physiological response of root and leaf to Cp2 treatment was stronger than that of stem. The physiological indicators with the greatest response to Cp2 infection were further explored through principal component analysis, and superoxide dismutase, peroxidase, ascorbate peroxidase, and soluble protein showed the greatest changes in roots, stems, and leaves (P < 0.001). Among tissues, the commonality was the change of soluble protein. Therefore, soluble protein is speculated to be a physiological marker during alfalfa-E. persicina interactions. These findings indicate that once E. persicina spreads from alfalfa seeds to the rhizosphere, it can invade alfalfa roots and cause disease. This study demonstrates that this plant pathogenic bacterium may be a potential threat to new environment when they spread via seed trade and these "dangerous hitchhikers" warrant further attention, especially in the study of bacterial diseases in pasture-based production systems.