Revealing the Orbital Interactions between Dissimilar Metal Sites during Oxygen Reduction Process.

A FeCo/DA@NC catalyst with the well-defined FeCoN6 moiety is customized through a novel and ultrafast Joule heating technique. This catalyst demonstrates superior oxygen reduction reaction activity and stability in an alkaline environment. The power density and charge-discharge cycling of znic-air batteries driven by FeCo/DA@NC also surpass those of Pt/C catalyst. The source of the excellent oxygen reduction reaction activity of FeCo/DA@NC originates from the significantly changed charge environment and 3d orbital spin state. These not only improve the bonding strength between active sites and oxygen-containing intermediates, but also provide spare reaction sites for oxygen-containing intermediates. Moreover, various in situ detection techniques reveal that the rate-determining step in the four-electron oxygen reduction reaction is *O2 protonation. This work provides strong support for the precise design and rapid preparation of bimetallic catalysts and opens up new ideas for understanding orbital interactions during oxygen reduction reactions.

Regulating the Lithium Ions' Local Coordination Environment through Designing a COF with Single Atomic Co Site to Achieve Dendrite-Free Lithium-Metal Batteries.

The detrimental growth of lithium dendrites and unstable solid electrolyte interphase (SEI) inhibit the practical application of lithium-metal batteries. Herein, atomically dispersed cobalt coordinate conjugated bipyridine-rich covalent organic framework (sp2 c-COF) is explored as an artificial SEI on the surface of the Li-metal anode to resolve these issues. The single Co atoms confined in the structure of COF enhance the number of active sites and promote electron transfer to the COF. The synergistic effects of the Co─N coordination and strong electron-withdrawing cyano-group can adsorb the electron from the donor (Co) at a maximum and create an electron-rich environment, hence further regulating the Li+ local coordination environment and achieving uniform Li-nucleation behavior. Furthermore, in situ technology and density functional theory calculations reveal the mechanism of the sp2 c-COF-Co inducing Li uniform deposition and promoting Li+ rapid migration. Based on these advantages, the sp2 c-COF-Co modified Li anode exhibits a low Li-nucleation barrier of 8 mV, and excellent cycling stability of 6000 h.

Antibiotic synergist OM19r reverses aminoglycoside resistance in multidrug-resistant Escherichia coli.

Introduction: The continued emergence and spread of multidrug-resistant (MDR) bacterial pathogens require a new strategy to improve the efficacy of existing antibiotics. Proline-rich antimicrobial peptides (PrAMPs) could also be used as antibacterial synergists due to their unique mechanism of action. Methods: Utilizing a series of experiments on membrane permeability, In vitro protein synthesis, In vitro transcription and mRNA translation, to further elucidate the synergistic mechanism of OM19r combined with gentamicin. Results: A proline-rich antimicrobial peptide OM19r was identified in this study and its efficacy against Escherichia coli B2 (E. coli B2) was evaluated on multiple aspects. OM19r increased antibacterial activity of gentamicin against multidrug-resistance E. coli B2 by 64 folds, when used in combination with aminoglycoside antibiotics. Mechanistically, OM19r induced change of inner membrane permeability and inhibited translational elongation of protein synthesis by entering to E. coli B2 via intimal transporter SbmA. OM19r also facilitated the accumulation of intracellular reactive oxygen species (ROS). In animal models, OM19r significantly improved the efficacy of gentamicin against E. coli B2. Discussion: Our study reveals that OM19r combined with GEN had a strong synergistic inhibitory effect against multi-drug resistant E. coli B2. OM19r and GEN inhibited translation elongation and initiation, respectively, and ultimately affected the normal protein synthesis of bacteria. These findings provide a potential therapeutic option against multidrug-resistant E. coli.

Downregulated miR-181a alleviates H2O2-induced oxidative stress and cellular senescence by targeting PDIA6 in human foreskin fibroblasts

Abstract Background Oxidative stress is strongly associated with cellular senescence. Numerous studies have indicated that microRNAs (miRNAs) play a critical part in cellular senescence. MiR-181a was reported to induce cellular senescence, however, the potential mechanism of miR-181a in hydrogen peroxide (H2O2)-induced cellular senescence remains obscure. Objective The aim of this study is to investigate the role and regulatory mechanism of miR-181a in H2O2-induced cellular senescence. Methods Human foreskin fibroblasts (HFF) transfected with miR-181a inhibitor/miR-NC with or without H2O2 treatment were divided into four groups: control + miR-NC/miR-181a inhibitor, H2O2 + miR-NC/miR-181a inhibitor. CCK-8 assay was utilized to evaluate the viability of HFF. RT-qPCR was used to measure the expression of miR-181a and its target genes. Protein levels of protein disulfide isomerase family A member 6 (PDIA6) and senescence markers were assessed by western blotting. Senescence-associated β-galactosidase (SA-β-gal) staining was applied for detecting SA-β-gal activity. The activities of SOD, GPx, and CAT were detected by corresponding assay kits. The binding relation between PDIA6 and miR-181a was identified by luciferase reporter assay. Results MiR-181a inhibition suppressed H2O2-induced oxidative stress and cellular senescence in HFF. PDIA6 was targeted by miR-181a and lowly expressed in H2O2-treated HFF. Knocking down PDIA6 reversed miR-181a inhibition-mediated suppressive impact on H2O2-induced oxidative stress and cellular senescence in HFF. Study limitations Signaling pathways that might be mediated by miR-181a/PDIA6 axis were not investigated. Conclusion Downregulated miR-181a attenuates H2O2-induced oxidative stress and cellular senescence in HFF by targeting PDIA6.

Downregulated miR-181a alleviates H2O2-induced oxidative stress and cellular senescence by targeting PDIA6 in human foreskin fibroblasts.

BACKGROUND: Oxidative stress is strongly associated with cellular senescence. Numerous studies have indicated that microRNAs (miRNAs) play a critical part in cellular senescence. MiR-181a was reported to induce cellular senescence, however, the potential mechanism of miR-181a in hydrogen peroxide (H2O2)-induced cellular senescence remains obscure. OBJECTIVE: The aim of this study is to investigate the role and regulatory mechanism of miR-181a in H2O2-induced cellular senescence. METHODS: Human foreskin fibroblasts (HFF) transfected with miR-181a inhibitor/miR-NC with or without H2O2 treatment were divided into four groups: control + miR-NC/miR-181a inhibitor, H2O2 + miR-NC/miR-181a inhibitor. CCK-8 assay was utilized to evaluate the viability of HFF. RT-qPCR was used to measure the expression of miR-181a and its target genes. Protein levels of protein disulfide isomerase family A member 6 (PDIA6) and senescence markers were assessed by western blotting. Senescence-associated ß-galactosidase (SA-ß-gal) staining was applied for detecting SA-ß-gal activity. The activities of SOD, GPx, and CAT were detected by corresponding assay kits. The binding relation between PDIA6 and miR-181a was identified by luciferase reporter assay. RESULTS: MiR-181a inhibition suppressed H2O2-induced oxidative stress and cellular senescence in HFF. PDIA6 was targeted by miR-181a and lowly expressed in H2O2-treated HFF. Knocking down PDIA6 reversed miR-181a inhibition-mediated suppressive impact on H2O2-induced oxidative stress and cellular senescence in HFF. STUDY LIMITATIONS: Signaling pathways that might be mediated by miR-181a/PDIA6 axis were not investigated. CONCLUSION: Downregulated miR-181a attenuates H2O2-induced oxidative stress and cellular senescence in HFF by targeting PDIA6.

Inferring regulatory element landscapes and gene regulatory networks from integrated analysis in eight hulless barley varieties under abiotic stress.

BACKGROUND: The cis-regulatory element became increasingly important for resistance breeding. There were many DNA variations identified by resequencing. To investigate the links between the DNA variations and cis-regulatory element was the fundamental work. DNA variations in cis-regulatory elements caused phenotype variations in general. RESULTS: We used WGBS, ChIP-seq and RNA-seq technology to decipher the regulatory element landscape from eight hulless barley varieties under four kinds of abiotic stresses. We discovered 231,440 lowly methylated regions (LMRs) from the methylome data of eight varieties. The LMRs mainly distributed in the intergenic regions. A total of 97,909 enhancer-gene pairs were identified from the correlation analysis between methylation degree and expression level. A lot of enriched motifs were recognized from the tolerant-specific LMRs. The key transcription factors were screened out and the transcription factor regulatory network was inferred from the enhancer-gene pairs data for drought stress. The NAC transcription factor was predicted to target to TCP, bHLH, bZIP transcription factor genes. We concluded that the H3K27me3 modification regions overlapped with the LMRs more than the H3K4me3. The variation of single nucleotide polymorphism was more abundant in LMRs than the remain regions of the genome. CONCLUSIONS: Epigenetic regulation is an important mechanism for organisms to adapt to complex environments. Through the study of DNA methylation and histone modification, we found that many changes had taken place in enhancers and transcription factors in the abiotic stress of hulless barley. For example, transcription factors including NAC may play an important role. This enriched the molecular basis of highland barley stress response.

Resistance to Powdery Mildew in Qingke Involves the Accumulation of Aromatic Phenolamides Through Jasmonate-Mediated Activation of Defense-Related Genes.

Powdery mildew (PM) leads to severe yield reduction in qingke (Hordeum vulgare L. var. nudum). Although studies have focused on identifying PM-related resistance genes, mechanistic insights into the metabolic regulation networks of resistance against PM have rarely been explored in qingke. Here, we integrated transcriptomic, proteomic and metabolomic data using PM-susceptible (G72) and PM-resistant (K69) accessions to systemically explore the mechanisms of PM resistance. The integrated results show that a rapidly transduction of jasmonic acid (JA) and (+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile), and importantly, a inducing accumulation of aromatic PAs conferred qingke-specific resistance for PM stress. Functional analysis revealed that the four BAHD N-acyltransferase genes were responsible for the synthesis of aliphatic and aromatic PAs. The expression of the four genes are induced by methyl jasmonate (MeJA) and PM treatment. Co-expression network analysis shows that a histone lysine demethylase, JMJ705 gene, also induced by MeJA and PM treatment, had highly correlation with PAs biosynthesis. Chromatin immunoprecipitation (ChIP)-seq assays revealed that the level of trimethylated histone H3 lysine 27 (H3K27me3) of the four genes in MeJA and PM-treated plants was significantly reduced. Overall, our results suggest that a novel strategy for jasmonic acid signal-mediated demethylation controlling the accumulation of aromatic PAs to enhance plant immune resistance through removal of H3K27me3 and activating defense-related gene expression.

Endolymphatic Hydrop Phenotype in Familial Norrie Disease Caused by Large Fragment Deletion of NDP.

Norrie disease (ND; OMIM 310600), a rare X-linked recessive genetic disorder, is characterized by congenital blindness and occasionally, sensorineural hearing loss, and developmental delay. The congenital blindness of ND patients is almost untreatable; thus, hearing is particularly important for them. However, the mechanism of hearing loss of ND patients is unclear, and no good treatment is available except wearing hearing-aid. Therefore, revealing the mechanism of hearing loss in ND patients and exploring effective treatment methods are greatly important. In addition, as a serious monogenic genetic disease, convenient gene identification method is important for ND patients and their family members, as well as prenatal diagnosis and preimplantation genetic diagnosis to block intergenerational transmission of pathogenic genes. In this study, a Norrie family with two male patients was reported. This pedigree was ND caused by large fragment deletion of NDP (norrin cystine knot growth factor NDP) gene. In addition to typical severe ophthalmologic and audiologic defects, the patients showed new pathological features of endolymphatic hydrops (EH), and they also showed acoustic nerves abnormal as described in a very recent report. PCR methods were developed to analyze and diagnose the variation of the family members. This study expands the understanding of the clinical manifestation and pathogenesis of ND and provides a new idea for the treatment of patients in this family and a convenient method for the genetic screen for this ND family.

Discovery of a novel antibacterial protein CB6-C to target methicillin-resistant Staphylococcus aureus.

Given a serious threat of multidrug-resistant bacterial pathogens to global healthcare, there is an urgent need to find effective antibacterial compounds to treat drug-resistant bacterial infections. In our previous studies, Bacillus velezensis CB6 with broad-spectrum antibacterial activity was obtained from the soil of Changbaishan, China. In this study, with methicillin-resistant Staphylococcus aureus as an indicator bacterium, an antibacterial protein was purified by ammonium sulfate precipitation, Sephadex G-75 column, QAE-Sephadex A 25 column and RP-HPLC, which demonstrated a molecular weight of 31.405 kDa by SDS-PAGE. LC-MS/MS analysis indicated that the compound was an antibacterial protein CB6-C, which had 88.5% identity with chitosanase (Csn) produced by Bacillus subtilis 168. An antibacterial protein CB6-C showed an effective antimicrobial activity against gram-positive bacteria (in particular, the MIC for MRSA was 16 µg/mL), low toxicity, thermostability, stability in different organic reagents and pH values, and an additive effect with conventionally used antibiotics. Mechanistic studies showed that an antibacterial protein CB6-C exerted anti-MRSA activity through destruction of lipoteichoic acid (LTA) on the cell wall. In addition, an antibacterial protein CB6-C was efficient in preventing MRSA infections in in vivo models. In conclusion, this protein CB6-C is a newly discovered antibacterial protein and has the potential to become an effective antibacterial agent due to its high therapeutic index, safety, nontoxicity and great stability.

An Antibacterial Peptide with High Resistance to Trypsin Obtained by Substituting d-Amino Acids for Trypsin Cleavage Sites.

The poor stability of antibacterial peptide to protease limits its clinical application. Among these limitations, trypsin mainly exists in digestive tract, which is an insurmountable obstacle to orally delivered peptides. OM19R is a random curly polyproline cationic antimicrobial peptide, which has high antibacterial activity against some gram-negative bacteria, but its stability against pancreatin is poor. According to the structure-activity relationship of OM19R, all cationic amino acid residues (l-arginine and l-lysine) at the trypsin cleavage sites were replaced with corresponding d-amino acid residues to obtain the designed peptide OM19D, which not only maintained its antibacterial activity but also enhanced the stability of trypsin. Proceeding high concentrations of trypsin and long-time (such as 10 mg/mL, 8 h) treatment, it still had high antibacterial activity (MIC = 16-32 µg/mL). In addition, OM19D also showed high stability to serum, plasma and other environmental factors. It is similar to its parent peptide in secondary structure and mechanism of action. Therefore, this strategy is beneficial to improve the protease stability of antibacterial peptides.

Drought Resistance in Qingke Involves a Reprogramming of the Phenylpropanoid Pathway and UDP-Glucosyltransferase Regulation of Abiotic Stress Tolerance Targeting Flavonoid Biosynthesis.

Tibetan hulless barley (qingke) is an important food crop in the Tibetan plateau. However, it often suffers from drought stress resulting in reduction of food production because of the extreme plateau environment. To elucidate the molecular mechanisms underlying the drought resistance of qingke, the transcriptomic and metabolomic responses of drought-sensitive (D) and drought-resistant (XL) accessions were characterized in experiments with a time course design. The phenylpropanoid pathway was reprogrammed by downregulating the lignin pathway and increasing the biosynthesis of flavonoids and anthocyanins, and this regulation improved plant tolerance for drought stress. Besides, flavonoid glycosides have induced accumulation of metabolites that participated in drought stress resistance. HVUL7H11410 exhibited the activity of wide-spectrum glucosyltransferase and mediated flavonoid glycosylation to enhance drought stress resistance. Overall, the findings provide insights into the regulatory mechanism underlying drought stress tolerance associated with metabolic reprogramming. Furthermore, the flavonoid-enriched qingke is more tolerant to drought stress and can be used as a functional food to benefit human health.

Magnetic resonance imaging differentiates locoregional flaps from free flaps after reconstructive surgical treatment of tongue cancer.

OBJECTIVE: The aim of this study was to compare magnetic resonance imaging (MRI) features of reconstruction with locoregional flaps (LRFs) with free flaps (FFs) after surgical treatment for tongue cancer. STUDY DESIGN: In total, 115 cases of postoperative tongue carcinoma (67 cases of LRF surgery and 48 cases of FF surgery) were retrospectively reviewed. All patients had undergone nonenhanced and contrast-enhanced MRI at 0-4, 5-12, and 13-48 months after surgery. Signal intensity, margins, maximal size, contrast enhancement, change in the hyoglossus and mylohyoid muscles, recurrence, lymph node metastasis, and complications were evaluated. RESULTS: Significant differences were found between LRF and FF for signal intensity (P < .001) in all 3 periods, with LRF mostly isointense with muscle on T1-weighted images (T1WIs) and FF producing mixed hyperintensity with muscular striations in all cases in T1WIs and T2-weighted images (T2 WIs). Margin definition was similar between groups in the early period, but sharp margins were more common in FF after 4 months (P ≤ .018). LRF was significantly smaller than FF in all periods (P ≤ .017). Both mylohyoid and hyoglossus enlargements were common in the early period in both groups, but all cases became atrophic later. CONCLUSIONS: MRI can differentiate LRFs from FFs in a variety of parameters after flap reconstructive surgery for tongue cancer.

miR-194-5p serves a suppressive role in human keloid fibroblasts via targeting NR2F2.

Keloids are a skin fibrotic disease that cause a number of problems for reconstructive surgeons. MicroRNAs (miRs) are crucial for the development of keloids. The present study aimed to investigate the function of the miR­194­5p/nuclear receptor subfamily 2 group F member 2 (NR2F2) interactome in human keloid fibroblasts. Microarray analysis was performed to identify key genes that may participate in keloid progression. The expression levels of miR­194­5p and NR2F2 mRNA in normal human skin fibroblasts (HSFs) and human keloid fibroblasts (KEL­FIBs) were measured via reverse transcription­quantitative PCR. Furthermore, cell proliferation, apoptosis, migration and invasion were assessed in KEL­FIB cells. Following NR2F2 knockdown and miR­194­5p inhibition, NR2F2 expression was measured via western blotting. The microarray analysis identified NR2F2 as a key gene related to keloids. The regulatory association between miR­194­5p and NR2F2 was identified using TargetScan Human (version 7.2) and verified by performing a dual­luciferase reporter assay. miR­194­5p expression was decreased in KEL­FIB cells compared with HSF cells, and miR­194­5p overexpression inhibited the aggressive phenotypes of KEL­FIB cells compared with the negative control group. Meanwhile, NR2F2 expression was negatively correlated with miR­194­5p expression. NR2F2 knockdown and miR­194­5p overexpression displayed similar effects on KEL­FIB cells. Moreover, NR2F2 knockdown effectively reversed miR­194­5p inhibitor­mediated effects in keloid fibroblasts. The present study indicated that the novel miR/194­5p/NR2F2 interactome might be involved in the progression of keloid aggression and may serve as a potential therapeutic target for human keloid in the future.

Quantitative Proteome Profiling Provides Insight into the Proteins Associated with ß-Glucan Accumulation in Hull-less Barley Grains.

The hull-less barley (Qingke) is widely planted as a staple food crop in the Tibetan area, China, and the grains contains high content of ß-glucan (BG). The mechanisms of BG synthesis and accumulation in qingke has not been studied at the protein level. This study characterized the proteins associated with BG synthesis and accumulation during qingke seed development. The proteome profiles of qingke seeds taken at 20, 30, and 40 days after flowering were compared using the TMT-based quantitative proteomics. A total of 4283 proteins were identified, with 759 being differentially expressed (DEPs) throughout seed development. Comparisons of protein expression pattern, functions, and pathway enrichment tests highlight cell wall modification, carbon and energy metabolism, polysaccharide metabolism, post-transcriptional modifications, and vesicular transport as critical biological processes related to qingke BG accumulation. Furthermore, induction of starch synthase, starch branching enzyme, pectin acetyl esterases, beta-glucosidases, beta-amylases, 1,4-beta-xylan, xyloglucan, α-amylase inhibitors, and glycosyltransferases underpinned BG synthesis. The results also indicated that the proteins involved in glycolytic, gluconeogenesis, and glyoxylate bypass pathways provided energy and reducing power for BG storage. Parallel reaction monitoring (PRM) and quantitative real-time PCR (qPCR) analyses confirmed the expression profile of the proteins obtained by TMT-based proteomics. The current results provided an insight into the mechanisms of BG synthesis and accumulation during qingke seed development.

Preparation, Characterization and Pharmacokinetic Study of N-Terminal PEGylated D-Form Antimicrobial Peptide OM19r-8.

Recently, new cationic antibacterial peptide OM19R has been designed with low minimum inhibitory concentration (MIC) values against some gram-negative bacteria, such as Escherichia coli, Salmonella, and Shigella. However, this hybrid peptide, like most antibacterial peptides, has low enzyme stability and short half-life, which, in turn, increases the drug's cost. In this study, an antibacterial peptide (OM19r-8) was obtained containing some D-Arg amino acids. The new preparations were carried out through the replacement of l-Arginine by d-Arginine and the addition of PEG chains. Firstly, eight OM19r series of antibacterial peptides were obtained by designing D-Arg. Then, a polyethylene glycol-modified product mPEG5-butyrALD-OM19r-8 (mPEG5-OM19r-8) was isolated and purified by reverse-phase high-performance liquid chromatography (RT-HPLC). The enzyme stability test showed that the resistance of antibacterial peptide OM19r-8 to protease degradation increased by 4-32-fold. Moreover, the Time-kill studies showed that the germicidal kinetics curves of mPEG5-OM19r-8 and OM19r-8 to Escherichia coli had a similar trend, thus suggesting that PEG modification has an acceptable effect on the activity of the original peptide. Furthermore, the elimination of half-life (28.09 ± 2.81min) of mPEG5-OM19r-8, and the area under the drug concentration-time curve (2686.48 ± 651.36min∗ug/ml) was significantly prolonged. The current study demonstrates an example that optimizes the AMP by utilizing L-to-D amino acid replacement and including PEG chains. These results provide useful data for the clinical application of the mPEG5-OM19r-8.

Structural characteristic of a sulfated polysaccharide from Gracilaria Lemaneiformis and its lipid metabolism regulation effect.

A sulfated polysaccharide extracted from Gracilaria lemaneiformis (GLP) with a prominent effect in regulating lipid metabolism was isolated. The molecular weight was 31.5 kDa and it was composed mainly of galactose, glucose and xylose. Fourier-transform infrared (FT-IR) spectrum and nuclear magnetic resonance (NMR) analysis suggested that GLP was composed of the following repeating unit: [3-ß-Gal-4(OSO3)-1→4-α-3,6-anhydrogal-2(OSO3)-1→]. GLP could significantly decrease serum total cholesterol, triglyceride and free fatty acid levels and lower alanine aminotransferase and aspartate aminotransferase activities in high-fat-diet mice. Additionally, GLP could keep the body weight and attenuate accumulation of fat surrounding the liver and epididymis induced by high-fat diet. Results of RT-PCR indicated that GLP might regulate lipid metabolism and accelerate free fatty acid oxidation by up-regulating the expression of the PPARα, ACS and CPT1a gene. The present study suggests that GLP may be potentially useful for regulating lipid metabolism.

An improved high-quality genome assembly and annotation of Tibetan hulless barley.

Hulless barley (Hordeum vulgare L. var. nudum) is a barley variety that has loose husk cover of the caryopses. Because of the ease in processing and edibility, hulless barley has been locally cultivated and used as human food. For example, in Tibetan Plateau, hulless barley is the staple food for human and essential livestock feed. Although the draft genome of hulless barley has been sequenced, the assembly remains fragmented. Here, we reported an improved high-quality assembly and annotation of the Tibetan hulless barley genome using more than 67X PacBio long-reads. The N50 contig length of the new assembly is at least more than 19 times larger than other available barley assemblies. The new genome assembly also showed high gene completeness and high collinearity of genome synteny with the previously reported barley genome. The new genome assembly and annotation will not only remove major hurdles in genetic analysis and breeding of hulless barley, but will also serve as a key resource for studying barley genomics and genetics.

Comparative metabolomics analysis of the response to cold stress of resistant and susceptible Tibetan hulless barley (Hordeum distichon).

Plants cultivated on the Qinghai-Tibetan Plateau grow in an extremely cold environment and thus are exposed to cold stress. To assess the metabolic processes during cold exposure of Tibetan hulless barley (Hordeum distichon L.), metabolic analyses were conducted on one tolerant (XiLa) and one sensitive (ZangQing) cultivar exposed to six temperatures (24 °C, 12 °C, 5 °C, 0 °C, -5 °C, -8 °C) for 24 h. In total, 770 metabolites were identified, including amino acids and derivatives, carbohydrates, flavonoids, lipids, nucleotides and derivatives, and phenolamides. In principal component analysis, the samples were clearly grouped according to the cultivar, suggesting that the two cultivars have differential responses to cold stress. In cold-grown plants, eight metabolites, including monoacylglycerol (MAG, 18:2), MAG (18:3), deoxyadenosine, 6-methylmercaptopurine, and coniferin, were significantly altered in XiLa, but not in ZangQing when compared to the levels in control plants, and thus, these compounds can be considered as potential biomarkers of exposure to cold stress in hulless barley. Furthermore, differentially altered metabolites between seedlings exposed to -8 °C and those maintained at 24 °C were significantly enriched in glutathione metabolism. The findings of this study will be useful for the development of cultivars with cold stress tolerance.

Comparative proteomics analysis of Tibetan hull-less barley under osmotic stress via data-independent acquisition mass spectrometry.

BACKGROUND: Tibetan hull-less barley (Hordeum vulgare L. var. nudum) is one of the primary crops cultivated in the mountains of Tibet and encounters low temperature, high salinity, and drought. Specifically, drought is one of the major abiotic stresses that affect and limit Tibetan barley growth. Osmotic stress is often simultaneously accompanied by drought conditions. Thus, to improve crop yield, it is critical to explore the molecular mechanism governing the responses of hull-less barley to osmotic/drought stress conditions. FINDINGS: In this study, we used quantitative proteomics by data-independent acquisition mass spectrometry to investigate protein abundance changes in tolerant (XL) and sensitive (DQ) cultivars. A total of 6,921 proteins were identified and quantified in all samples. Two distinct strategies based on pairwise and time-course comparisons were utilized in the comprehensive analysis of differentially abundant proteins. Further functional analysis of differentially abundant proteins revealed that some hormone metabolism-associated and phytohormone abscisic acid-induced genes are primarily affected by osmotic stress. Enhanced regulation of reactive oxygen species (may promote the tolerance of hull-less barley under osmotic stress. Moreover, we found that some regulators, such as GRF, PR10, MAPK, and AMPK, were centrally positioned in the gene regulatory network, suggesting that they may have a dominant role in the osmotic stress response of Tibetan barley. CONCLUSIONS: Our findings highlight a subset of proteins and processes that are involved in the alleviation of osmotic stress. In addition, this study provides a large-scale and multidimensional proteomic data resource for the further investigation and improvement of osmotic/drought stress tolerance in hull-less barley or other plant species.

Genomic island type IV secretion system and transposons in genomic islands involved in antimicrobial resistance in Trueperella pyogenes.

Trueperella pyogenes (T. pyogenes) is a well-known opportunistic pathogen of many animal species. It can cause a variety of suppurative infections. The objective of this research was to get insight into the gene context and the location of the antimicrobial resistance determinants in the two multi-resistant T. pyogenes isolates TP3 and TP4. Comparative analysis of key factors leading to antimicrobial resistance was performed. Both isolates were resistant to erythromycin, azithromycin and tetracycline, and susceptible to ciprofloxacin, enrofloxacin, cefazolin and florfenicol. In addition, TP4 was resistant to amikacin and gentamicin. Whole-genome analyses revealed that both TP3 and TP4 contained two different genomic islands (TP3-GI1, TP3-GI5, TP4-GI5 and TP4-GI8) involved in multi-drug resistance. There is a common region in TP3-GI1 and TP4-GI5, containing the tetracycline resistance gene tet(W) and a series of genes involved in type IV secretion systems. Several genes located on TP3-GI5 and TP4-GI8 are highly homologous. Tetracycline-resistance gene tet(33) was potentially acquired by horizontal gene transfer via IS6100 located on 57,936 bp TP3-GI5. The macrolide resistance gene erm(X) was located near the end of the TP3-GI5. The sequence analysis of TP4-GI8 showed that two copies of erm(X) and two IS1634 elements located in the same orientation may have formed a composite transposon. GI-type T4SS, transposons and multiple resistance genes located on GIs play a key role in multiple drug resistance of TP3 and TP4.