Motility Ability Research Articles

RpoS sigma factor mediates adaptation and virulence in Vibrio mimicus

The alternative sigma factor RpoS functions as a regulator of stress and virulence response in numerous bacterial species. Vibrio mimicus is a critical opportunistic pathogen causing huge losses to aquaculture. However, the exact role of RpoS in V. mimicus remains unclear. In this study, rpoS deletion mutant of V. mimicus was constructed through allelic exchange and the phenotypic and transcriptional changes were investigated to determine the function of RpoS. The abilities of growth, motility, biofilm production, hemolytic activity and pathogenicity were significantly impaired in ΔrpoS strain. Stationary-phase cells of ΔrpoS strain showed lower tolerance to H2O2, heat, ethanol, and starvation stress than the wild-type strain. Transcriptome analyses revealed the involvement of rpoS in various cellular processes, notably bacterial-type flagellum synthesis and assembly, membrane synthesis and assembly and response to various stimuli. Phenotypic and RNA-seq analysis revealed that RpoS is required for biofilm formation, stress resistance, and pathogenicity in V. mimicus. Furthermore, β-galactosidase activity showed that rpoS is essential for optimal transcription of the flgK, fliA, cheA, mcpH mRNA. These results offer significant insight into the function and regulatory network of rpoS/RpoS, thereby improving our understanding and facilitating selection of molecular targets for future prevention strategies against V. mimicus.

Insights into macrolide resistance in Arcobacter butzleri: potential resistance mechanisms and impact on bacterial fitness and virulence.

Macrolides are recommended for treating the emerging enteropathogen Arcobacter butzleri; nonetheless, this bacterium often exhibits highly variable resistance rates, and the mechanisms behind this resistance phenotype remain largely unexplored. To understand the phenotypic and genotypic consequences associated with the acquisition of erythromycin resistance in A. butzleri, as well as the effects on the fitness of this species. Resistant strains resulting from spontaneous mutations and adaptive laboratory evolution under increasing erythromycin concentrations were examined regarding their cross-resistance and collateral susceptibility profiles. Genetic causes of phenotypic antibiotic resistance were analysed by sequencing and bioinformatics, with functional correlation through ethidium bromide accumulation assays. Growth profiles in the presence and absence of erythromycin, motility and biofilm formation abilities were assessed to detect potential changes in fitness and virulence. Clones from spontaneous mutation rate evolution demonstrated decreased susceptibility to erythromycin and other classes of antibiotics, associated with mutations in the transcriptional repressor areR, causing overexpression of the AreABC efflux pump. In turn, WGS analysis of the evolved strain showed additional mutations in the ribosomal proteins L4 and L22 and in the areR gene. Furthermore, the acquisition of macrolide resistance altered A. butzleri virulence and entailed a high biological cost. The findings of this study have proved that efflux activity contributes synergistically with mutations in the ribosomal proteins L4 and L22 to A. butzleri's high-level macrolide resistance. The results further suggest an impact on the bacterial physiology and virulence, with the increased fitness cost justifying the low worldwide prevalence of high-level resistant circulating strains.

Drosophila melanogaster sperm turn more oxidative in the female.

Males and females of many species store sperm for extended periods. During storage, sperm are predicted to undergo cellular and functional changes, especially towards glycolytic energy metabolism because oxygen radicals derived from oxidative phosphorylation can affect sperm motility and fertilisation ability. However, not all species can use both major energy metabolism pathways. Here, we examined the fruit fly Drosophila melanogaster and asked whether sperm metabolism can be fuelled by both glycolysis and oxidative phosphorylation, and to what extent metabolism changes during storage. Inhibiting glycolysis in vitro led to a more oxidative state of sperm; inhibiting oxidative phosphorylation increased the glycolytic component, assessed by multi-photon autofluorescence lifetime imaging (FLIM) of NAD(P)H. We further examined sperm in male and female sperm storage organs using FLIM of NAD(P)H and FAD. In intact storage organs, we found that, unexpectedly, (i) sperm were more oxidative in females than in males, and (ii) oxidative phosphorylation increased with storage duration in females. Our observation that the relative contribution of the two major energy metabolic pathways in D. melanogaster sperm differs in males and females and over storage time has important evolutionary implications.

Effect of L-HSL on biofilm and motility of Pseudomonas aeruginosa and its mechanism

Pseudomonas aeruginosa (P. aeruginosa) biofilm formation is a crucial cause of enhanced antibiotic resistance. Quorum sensing (QS) is involved in regulating biofilm formation; QS inhibitors block the QS signaling pathway as a new strategy to address bacterial resistance. This study investigated the potential and mechanism of L-HSL (N-(3-cyclic butyrolactone)-4-trifluorophenylacetamide) as a QS inhibitor for P. aeruginosa. The results showed that L-HSL effectively inhibited the biofilm formation and dispersed the pre-formed biofilm of P. aeruginosa. The production of extracellular polysaccharides and the motility ability of P. aeruginosa were suppressed by L-HSL. C. elegans infection experiment showed that L-HSL was non-toxic and provided protection to C. elegans against P. aeruginosa infection. Transcriptomic analysis revealed that L-HSL downregulated genes related to QS pathways and biofilm formation. L-HSL exhibits a promising potential as a therapeutic drug for P. aeruginosa infection.Key points• Chemical synthesis of N-(3-cyclic butyrolactone)-4-trifluorophenylacetamide, named L-HSL.• L-HSL does not generate survival pressure on the growth of P. aeruginosa and can inhibit the QS system.• KEGG enrichment analysis found that after L-HSL treatment, QS-related genes were downregulated.

Optimizing chitosan derived from Metapenaeus affinis: a novel anti-biofilm agent against Pseudomonas aeruginosa

Pseudomonas aeruginosa is a commonly found Gram-negative bacterium in healthcare facilities and is renowned for its ability to form biofilms and its virulence factors that are controlled by quorum sensing (QS) systems. The increasing prevalence of multidrug-resistant strains of this bacterium poses a significant challenge in the field of medicine. Consequently, the exploration of novel antimicrobial agents has become a top priority. This research aims to optimize chitosan derived from white shrimp (Metapenaeus affinis) using the Response Surface Methodology (RSM) computational approach. The objective is to investigate chitosan’s potential as a solution for inhibiting QS activity and biofilm formation in P. aeruginosa ATCC 10,145. Under optimized conditions, chitin was treated with NaOH (1.41 M) for 15.75 h, HCl (7.49% vol) for 2.01 h, and at a deacetylation temperature of 81.15 °C. The resulting chitosan exhibited a degree of deacetylation (DD%) exceeding 93.98%, as confirmed by Fourier-transform infrared (FTIR) spectral analysis, indicating its high purity. The extracted chitosan demonstrated a significant synergistic antibiotic effect against P. aeruginosa when combined with ceftazidime, enhancing its bactericidal activity by up to 15-fold. In addition, sub-MIC (minimum inhibitory concentration) concentrations of extracted chitosan (10 and 100 µg/mL) successfully reduced the production of pyocyanin and rhamnolipid, as well as the swimming motility, protease activity and biofilm formation ability in comparison to the control group (P < 0.05). Moreover, chitosan treatment downregulated the RhlR and LasR genes in P. aeruginosa when compared to the control group (P < 0.05). The optimized chitosan extract shows significant potential as a coating agent for surgical equipment, effectively preventing nosocomial infections caused by P. aeruginosa pathogens.

The p38/MAPK pathway as a therapeutic target to prevent therapeutic escape of breast cancer stem cells.

Cancer stem cells (CSCs) play an important role in metastasis development, tumor recurrence, and treatment resistance, and are essential for the eradication of cancer. Currently, therapies fail to eradicate CSCs due to their therapeutic stress-induced cellular escape, which leads to enhanced aggressive behaviors compared with CSCs that have never been treated. However, the underlying mechanisms regulating the therapeutic escape remain unknown. To this end, we established a model to isolate the therapeutic escaped CSCs (TSCSCs) from breast CSCs and performed the transcription profile to reveal the mechanism. Mechanistically, we demonstrated that the behavior of therapeutic escape was regulated through the p38/MAPK signaling pathway, resulting in TSCSCs exhibiting enhanced motility and metastasis. Notably, blocking the p38/MAPK signaling pathway effectively reduced motility and metastasis ability both in vitro and in vivo, which were further supported by downregulated motility-related genes and epithelial-mesenchymal transition (EMT)-related proteins vimentin and N-cadherin. The obtained findings reveal the p38/MAPK pathway as a potential therapeutic target for TSCSCs and would provide profound implications for cancer therapy.

Functional analysis of OmpA and its contribution to pathogenesis of Edwardsiella tarda

Outer membrane protein A (OmpA), a major component of outer membrane proteins in gram-negative bacteria, is considered to be an important virulence factor in various pathogenic bacteria, but its underlying mechanisms involved in pathogenic process of Edwardsiella tarda has not yet been fully elucidated. E. tarda is an important facultative intracellular pathogen with a broad host range. This bacterium could survive and replicate in macrophages as an escape mechanism from the host defense. To address the functions of OmpA and its potential roles in the pathogenesis of E. tarda, ΔompA mutant strain and ΔompA-C complementary strain were constructed by the allelic exchange method in this study. Here, we demonstrate that the abilities of motility, biofilm formation and adherence to RAW264.7 cells of ΔompA were significantly impaired, although there was no difference in growth between wild-type (WT) strain and ΔompA. Moreover, inactivation of ompA rendered E. tarda more sensitive to oxidative, heat shock and osmotic stress, which simulate the in vivo conditions that E. tarda encounters within the intramacrophage environment. Consist with this observation, ΔompA was also found to be markedly attenuated for growth within macrophages. In addition, compared with the WT strain, ΔompA activated macrophages to release more inflammatory mediators, including tumor necrosis factor alpha (TNF-α), reactive oxygen species (ROS) and nitric oxide (NO). However, flow cytometry analysis revealed that ΔompA induced less apoptosis of RAW264.7 cells as compared with WT strain, characterized by decreased Annexin V binding and the activation of caspase-3. Overall, our findings suggest an importance of OmpA to E. tarda and provide the first comprehensive insight into its functions and potential roles in the pathogenesis of E. tarda, including its effect on interaction with macrophages.

Expression and potential molecular mechanism of TOP2A in metastasis of non-small cell lung cancer

DNA topoisomerase II alpha (TOP2A) expression, gene alterations, and enzyme activity have been studied in various malignant tumors. Abnormal elevation of TOP2A expression is considered to be related to the development of non-small cell lung cancer (NSCLC). However, its association with tumor metastasis and its mode of action remains unclear. Bioinformatics, real-time quantitative PCR, immunohistochemistry and immunoblotting were used to detect TOP2A expression in NSCLC tissues and cells. Cell migration and invasion assays as well as cytoskeletal staining were performed to analyze the effects of TOP2A on the motility, migration and invasion ability of NSCLC cells. Cell cycle and apoptosis assays were used to verify the effects of TOP2A on apoptosis as well as cycle distribution in NSCLC. TOP2A expression was considerably upregulated in NSCLC and significantly correlated with tumor metastasis and the occurrence of epithelial–mesenchymal transition (EMT) in NSCLC. Additionally, by interacting with the classical ligand Wnt3a, TOP2A may trigger the canonical Wnt signaling pathway in NSCLC. These observations suggest that TOP2A promotes EMT in NSCLC by activating the Wnt/β-catenin signaling pathway and positively regulates malignant events in NSCLC, in addition to its significant association with tumor metastasis. TOP2A promotes the metastasis of NSCLC by stimulating the canonical Wnt signaling pathway and inducing EMT. This study further elucidates the mechanism of action of TOP2A, suggesting that it might be a potential therapeutic target for anti-metastatic therapy.

Exploring novel function of Gpx5 antioxidant activity: Assisting epididymal cells secrete functional extracellular vesicles.

Glutathione peroxisomal-5 (Gpx5) promotes the elimination of H2O2 or organic hydrogen peroxide, and plays an important role in the physiological process of resistance to oxidative stress (OS). To directly and better understand the protection of Gpx5 against OS in epididymal cells and sperm, we studied its mechanism of antioxidant protection from multiple aspects. To more directly investigate the role of Gpx5 in combating oxidative damage, we started with epididymal tissue morphology and Gpx5 expression profiles in combination with the mouse epididymal epithelial cell line PC1 (proximal caput 1) expressing recombinant Gpx5. The Gpx5 is highly expressed in adult male epididymal caput, and its protein signal can be detected in the sperm of the whole epididymis. Gpx5 has been shown to alleviate OS damage induced by 3-Nitropropionic Acid (3-NPA), including enhancing antioxidant activity, reducing mitochondrial damage, and suppressing cell apoptosis. Gpx5 reduces OS damage in PC1 and maintains the well-functioning extracellular vesicles (EVs) secreted by PC1, and the additional epididymal EVs play a role in the response of sperm to OS damage, including reducing plasma membrane oxidation and death, and increasing sperm motility and sperm-egg binding ability. Our study suggests that GPX5 plays an important role as an antioxidant in the antioxidant processes of epididymal cells and sperm, including plasma membrane oxidation, mitochondrial oxidation, apoptosis, sperm motility, and sperm-egg binding ability.

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.

Supplementation of Extender with Melatonin Improves the Motility, Mitochondrial Membrane Potential, and Fertilization Ability of Cryopreserved Brown-Marbled Grouper Sperm.

Sperm cryopreservation is a valuable tool for breeding, conservation, and genetic improvement in aquatic resources, while oxidative damage will cause a decline in sperm quality during this progress. Melatonin (MT), a natural antioxidant hormone, is used as an additive in sperm cryopreservation to reduce cellular damage from oxidative stress. Here, we aimed to investigate the effect of adding MT to the freezing medium in sperm cryopreservation of brown-marbled grouper (Epinephelus fuscoguttatus). Different concentrations of MT (0, 0.1, 0.25, and 0.5 mg/mL) were tested. We evaluated sperm motility, viability, apoptosis, mitochondrial membrane potential (MMP), and fertilization ability to assess the effects of MT supplementation. Our results demonstrated that the addition of MT to the extender improved the post-thaw motility, MMP, and fertilization ability of brown-marbled grouper sperm. The total motility, curvilinear velocity, straight linear velocity, and average path velocity in MT-treated groups (0.1 and 0.25 mg/mL) exhibited significantly higher values than that of the control group. A higher MMP (p < 0.05) was observed in the group treated with 0.25 mg/mL MT, suggesting that supplementation of MT in the extender might be able to protect mitochondrial membrane integrity effectively. Regarding fertilizing ability, 0.25 mg/mL MT yielded a significantly higher hatching rate than the control. An adverse effect was found with the concentration of MT up to 0.5 mg/mL, suggesting the possible toxicity of a high-dose addition. In this study, we optimized the sperm cryopreservation protocol of brown-marbled grouper, which might be valuable for sperm cryopreservation and sample commercialization of groupers and other fish.

Growth, biofilm formation, and motility of Listeria monocytogenes strains isolated from food and clinical samples located in Shanghai (China)

Listeria monocytogenes is a common foodborne pathogen that frequently causes global outbreaks. In this study, the growth characteristics, biofilm formation ability, motility ability and whole genome of 26 L. monocytogenes strains isolated from food and clinical samples in Shanghai (China) from 2020 to 2022 were analyzed. There are significant differences among isolates in terms of growth, biofilm formation, motility, and gene expression. Compared with other sequence type (ST) types, ST1930 type exhibited a significantly higher maximum growth rate, the ST8 type demonstrated a stronger biofilm formation ability, and the ST121 type displayed greater motility ability. Furthermore, ST121 exhibited significantly high mRNA expression levels compared with other ST types in virulence genes mpl, fbpA and fbpB, the quorum sensing gene luxS, starvation response regulation gene relA, and biofilm adhesion related gene bapL. Whole-genome sequencing (WGS) analyses indicated the isolates of lineage I were mostly derived from clinical, and the isolates of lineage II were mostly derived from food. The motility ability, along with the expression of genes associated with motility (motA and motB), exhibited a significantly higher level in lineage II compared with lineage I. The isolates from food exhibited significantly higher motility ability compared with isolates from clinical. By integrating growth, biofilm formation, motility phenotype with molecular and genotyping information, it is possible to enhance comprehension of the association between genes associated with these characteristics in L. monocytogenes.

Nicotine-derived nitrosamines promote renal cell carcinoma cell migration via binding to nicotinic acetylcholine receptors

Several risk factors such as smoking, obesity, diabetes, and hypertension are related to the incidence of kidney cancer. Renal cell carcinoma (RCC) originates from the renal tubular epithelium and is the major form of kidney cancer. Notably, the relative risk of RCC in smokers compared to non-smokers is 1.38 while revealing a dose-dependent risk reduction in smoking cessation. Carcinogenic substances in tobacco, specifically nicotine-derived nitrosamines like 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N'-nitrosonornicotine (NNN), were known to induce the formation of DNA adducts, mutating genes that potentially initiate cancers. In addition to carcinogenesis, nicotine-derived nitrosamines may also contribute to modify the malignant features, which accelerates the cancer progression. This study was aimed to evaluate the effects of NNK in the modulation RCC cell proliferation and motility, besides, the possible underlying mechanisms were also studied. Our findings showed differential expression of nicotinic acetylcholine receptor (nAChR) mRNA subunits between normal human renal tubular cell (HK-2) and RCC cells (Achn), suggesting that RCC cells may have the ability in respond to the stimuli of NNK. While NNK didn't significantly show an influence in RCC cell viability, it enhanced cell motility and migration ability. Utilizing specific inhibitors, it was inferred that NNK stimulates RCC cell migration via nAChR activation and subsequent calcium channel opening. Our research underscores the necessity of smoking cessation in RCC management, even as further studies on diverse RCC cell lines and real-world data are required.

Inhibition of piezo1 prevents chronic cerebral hypoperfusion-induced cognitive impairment and blood brain barrier disruption

Chronic cerebral hypoperfusion (CCH) plays a critical role in the onset and progression of vascular dementia (VD), which is now recognized as the second most common form of dementia after Alzheimer's disease (AD). The mechanosensitive piezo1 channel has been identified to play important roles in several neurological disorders. However, the roles and possible mechanisms of piezo1 in CCH-induced cognitive decline and blood brain barrier (BBB) disruption, as well as the underlying mechanisms remain elusive. In this study, the CCH model was established by bilateral common carotid artery occlusion in rats and by oxygen and glucose deprivation/reoxygenation (OGD/R) in bEnd.3 cells. The results demonstrated that the antagonist of piezo1 GsMTx4 ameliorated CCH-induced cognitive dysfunction and mitigated cerebral edema. Furthermore, this study indicated that GsMTx4 improved the permeability and integrity of BBB and protected cerebral microvasculature after CCH. In vitro, GsMTx4 improved cell viability, promoted the ability of cell motility and migration, and inhibited the degradation of BBB integrity-related proteins by inhibiting NLRP3 inflammasome activation. In addition, NLRP3 agonist abolished the beneficial effects of GsMTx4. Collectively, our results demonstrate that piezo1 might be involved in CCH-induced cognitive impairment and BBB damage, which may be at least partially mediated through regulation of NLRP3 inflammasome.

Transcriptomic analysis of Vibrio alginolyticus challenged by Rhizoma coptidis reveals mechanisms of virulence genes

Rhizoma coptidis, a Chinese herbal medicine widely used to treat various bacterial infections, has the potential to develop antibiotic substitutes to overcome the drug resistance of Vibrio alginolyticus. To study the inhibitory effect of R. coptidis on V. alginolyticus, we sequenced the transcriptomes of three groups of samples of wild-type V. alginolyticus (CK) and V. alginolyticus, which were stressed by 5 mg/mL R. coptidis for 2 h (RC_2 h) and 4 h (RC_4 h). CK was compared with RC_2 h and RC_4 h, respectively, and a total of 1565 differentially expressed genes (DEGs) (988 up-regulated and 577 down-regulated) and 1737 DEGs (1152 up-regulated and 585 down-regulated) were identified. Comparing RC_2 h with RC_4 h, 156 DEGs (114 up-regulated and 42 down-regulated) were identified. The ability of biofilm formation and motility of V. alginolyticus altered upon with different concentrations of R. coptidis. Interestingly, relative expression patterns of virulence genes appeared statistically significantly varied, upon different concentrations of R. coptidis extract. DEGs were annotated to the Gene Ontology (GO) database for function enrichment analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, the results showed that the main enriched pathways, was those related to the virulence of V. alginolyticus. This study provides a new perspective for understanding the complex pathogenic mechanism of V. alginolyticus. R. coptidis could potnetially be used as alternative or complimnetary to antibiotics to treat infections after further research.

Cyclic-di-AMP confers an invasive phenotype on Escherichia coli through elongation of flagellin filaments

BackgroundAdherent-invasive Escherichia coli (AIEC) is isolated from patients with Crohn’s disease (CD). AIEC can invade the intestinal epithelium, suggesting that it is involved in the development and pathogenesis of CD. However, the mechanism by which AIEC acquired the invasive phenotype remains unknown.ResultsThis study was designed to examine the mechanisms of AIEC invasiveness. We found that the flagellin (fliC) expression in AIEC was two-fold higher than that in non-AIEC strains, and this overexpression induced the formation of long-filament flagellin. Deletion of fliC in the AIEC LF82 strain resulted in the disappearance of flagellar filaments and attenuated the motility and invasive ability of the bacterium, suggesting that the formation of long filament flagellin induced by increased fliC expression is required by AIEC to invade the intestinal epithelium. In AIEC and non-AIEC K12 strains cultured in the presence of cyclic-di-AMP (c-di-AMP), the expression of fliC was enhanced, and flagellar filaments were elongated. Stimulation with c-di-AMP enhanced the bacterial motility and ability to invade epithelial cells, even in the non-AIEC K12 strain.ConclusionsOur findings show that c-di-AMP confers an AIEC-like phenotype on non-AIEC strains by enhancing the expression of fliC. The results should be useful for understanding the pathogenesis of CD.

Polyclonal anti-whole cell IgY passive immunotherapy shields against P. aeruginosa-induced acute pneumonia and burn wound infections in murine models

Pseudomonas aeruginosa (PA) is a multidrug-resistant (MDR) opportunistic pathogen causing severe hospital-, and community-acquired infections worldwide. Thus, the development of effective immunotherapy-based treatments is essential to combat the MDR-PA infections. In the current study, we evaluated the protective efficacy of polyclonal avian antibodies raised against inactivated whole cells of the PAO1 strain in murine models of acute pneumonia and burn wound. The efficacy of generated antibodies was evaluated against different PA strains through several in vitro, ex vivo and in vivo experiments. The results showed that the anti-PAO1-IgY effectively reduced the motility, biofilm formation and cell internalization ability, and enhanced the opsonophagocytic killing of PA strains through the formation of immobilized bacteria and induction of increased cell surface hydrophobicity. Furthermore, immunotherapy with anti-PAO1-IgY completely protected mice against all PA strains in both acute pneumonia and burn wound murine models. It was found to reduce the bacterial loads in infected burned mice through interfering with virulence factors that play vital roles in the early stages of PA infection, such as colonization and cell internalization. The immunotherapy with anti-PAO1-IgYs could be instrumental in developing effective therapies aimed at reducing the morbidity and mortality associated with PA infections.

Isolation and Characterization Identification of Edophytic Nitrogen-Fixing Bacteria from Peanut Nodules.

This work was carried out to isolate and perform molecular identification and selection of endophytic nitrogen-fixing bacteria (ENFB) to be utilized as biofertilizer. In this research, nodulous samples of peanuts were collected from inside dyke areas, namely, Phuoc Hung of An Phu, An Giang, Vietnam. Ten colonies were isolated from nutrient agar plates containing YMA's medium. All isolates were rod shaped, Gram negative, and no spore creation. Biochemical tests indicated that they were obligate aerobes, catalase, oxidase, urea hydrolysis, well motile ability, and no nitrate reduction. The salt tolerance observed that most survived at 0.5% and 2% salinity (except Enterobacter cloacae subsp. dissolvens strain LMG 2683), while at 4%, only 3 isolates (Bacillus aryabhattai strain CM44, Enterobacter asburiae strain IIWM-JS-07L, and Bacillus songklensis strain KCa6) and at 5% only, 2 isolates survived, namely, Enterobacter asburiae strain IIWM-JS-07L and Bacillus songklensis strain KCa6. The result showed that most of ten ENFB strains could adapt to the range of 25°C and 45°C (except Enterobacter cloacae subsp. dissolvens strain LMG 2683 and Enterobacter mori strain cjy13 at 25°C). Out of ten isolates, three were finally selected for the next studies, which potentially have N-fixing ability and are utilized as biofertilizer in agricultural cultivation.

Early short-term hypoxia promotes epidermal cell migration by activating the CCL2-ERK1/2 pathway and epithelial-mesenchymal transition during wound healing.

Due to vasculature injury and increased oxygen consumption, the early wound microenvironment is typically in a hypoxic state. We observed enhanced cell migration ability under early short-term hypoxia. CCL2 belongs to the CC chemokine family and was found to be increased in early hypoxic wounds and enriched in the extracellular signal-regulated kinase (ERK)1/2 pathway in our previous study. However, the underlying mechanism through which the CCL2-ERK1/2 pathway regulates wound healing under early short-term hypoxia remains unclear. Activation of epithelial-mesenchymal transition (EMT) is a key process in cancer cell metastasis, during which epithelial cells acquire the characteristics of mesenchymal cells and enhance cell motility and migration ability. However, the relationship between epithelial cell migration and EMT under early short-term hypoxia has yet to be explored. HaCaT cells were cultured to verify the effect of early short-term hypoxia on migration through cell scratch assays. Lentiviruses with silenced or overexpressed CCL2 were used to explore the relationship between CCL2 and migration under short-term hypoxia. An acute full-thickness cutaneous wound rat model was established with the application of an ERK inhibitor to reveal the hidden role of the ERK1/2 pathway in the early stage of wound healing. The EMT process was verified in all the above experiments through western blotting. In our study, we found that short-term hypoxia promoted cell migration. Mechanistically, hypoxia promoted cell migration through mediating CCL2. Overexpression of CCL2 via lentivirus promoted cell migration, while silencing CCL2 via lentivirus inhibited cell migration and the production of related downstream proteins. In addition, we found that CCL2 was enriched in the ERK1/2 pathway, and the application of an ERK inhibitor in vivo and in vitro verified the upstream and downstream relationships between the CCL2 pathway and ERK1/2. Western blot results both in vivo and in vitro demonstrated that early short-term hypoxia promotes epidermal cell migration by activating the CCL2-ERK1/2 pathway and EMT during wound healing. Our work demonstrated that hypoxia in the early stage serves as a stimulus for triggering wound healing through activating the CCL2-ERK1/2 pathway and EMT, which promote epidermal cell migration and accelerate wound closure. These findings provide additional detailed insights into the mechanism of wound healing and new targets for clinical treatment.

Involvement of Cannabinoid Receptors and Adenosine A2B Receptor in Enhanced Migration of Lung Cancer A549 Cells Induced by γ-Ray Irradiation.

Residual cancer cells after radiation therapy may acquire malignant phenotypes such as enhanced motility and migration ability, and therefore it is important to identify targets for preventing radiation-induced malignancy in order to increase the effectiveness of radiotherapy. G-Protein-coupled receptors (GPCRs) such as adenosine A2B receptor and cannabinoid receptors (CB1, CB2, and GPR55) may be involved, as they are known to have roles in proliferation, invasion, migration and tumor growth. In this study, we investigated the involvement of A2B and cannabinoid receptors in γ-radiation-induced enhancement of cell migration and actin remodeling, as well as the involvement of cannabinoid receptors in cell migration enhancement via activation of A2B receptor in human lung cancer A549 cells. Antagonists or knockdown of A2B, CB1, CB2, or GPR55 receptor suppressed γ-radiation-induced cell migration and actin remodeling. Furthermore, BAY60-6583 (an A2B receptor-specific agonist) enhanced cell migration and actin remodeling in A549 cells, and this enhancement was suppressed by antagonists or knockdown of CB2 or GPR55, though not CB1 receptor. Our results indicate that A2B receptors and cannabinoid CB1, CB2, and GPR55 receptors all contribute to γ-radiation-induced acquisition of malignant phenotypes, and in particular that interactions of A2B receptor and cannabinoid CB2 and GPR55 receptors play a role in promoting cell migration and actin remodeling. A2B receptor-cannabinoid receptor pathways may be promising targets for blocking the appearance of malignant phenotypes during radiotherapy of lung cancer.