Sour porridge, a fermented food from the Guangxi Zhuang Autonomous Region of China, contains an abundance of lactic acid bacteria and has high nutritional value. In this study, a strain of Schleiferilactobacillus harbinensis GX0002947 was isolated from naturally fermented sour porridge from Fusui County, Chongzuo City, Guangxi Zhuang Autonomous Region of China. The strain was highly effective in the fermentation of sour porridge. It was found that strain S. harbinensis GX0002947 showed good acid and bile salt resistance at pH 3.5, bile salt concentration of 0.3 g/100 mL, in artificial gastrointestinal fluids, and the bacterial population density was greater than 106 CFU/mL. The fermentation broth and culture supernatant of strain S. harbinensis GX0002947 showed effective antibacterial activity against the foodborne pathogens Escherichia coli, Staphylococcus aureus, and Bacillus cereus. The optimum fermentation process for sour porridge was found to consist of a fermentation temperature of 37°C, inoculation dose of 12.5%, and fermentation time of 96 h, resulting in a total protein content of 397.33 μg/mL and a total amino acid content of 629.63 μmol/mL in the sour porridge. In addition, the community diversity of fermented sour porridge was explored by high-throughput Illumina sequencing. The results showed that fermentation of sour porridge by S. harbinensis GX0002947 resulted in the formation of a unique microbial community. Metabolites were compared between sour porridge fermented by strain S. harbinensis GX0002947 and naturally fermented sour porridge and were analyzed by LC–MS. This identified 24 differential metabolites which primarily included amino acids, carbohydrates, and lipids, suggesting that the associated pathways played a key role in the fermentation of sour porridge by S. harbinensis GX0002947. In conclusion, this study used inoculation of lactic acid bacteria for the fermentation of sour porridge, and assessed differences in microbial community structure and metabolites after inoculation with S. harbinensis GX0002947. These findings provided a theoretical basis and technical support for sour porridge production.

Fermented vegetable foods, with their crisp taste, pleasant aroma, and digestive properties, are increasingly popular. This study investigated improved safety and quality of fermented mustard products, using two strains of lactic acid bacteria, Pediococcus pentosaceus M52 and Lactiplantibacillus pentosus H1, isolated from traditional naturally fermented sauerkraut from Nanning, Guangxi Zhuang Autonomous Region, China. The effects of co-inoculation of the two strains on the physicochemical properties of the food were assessed by measuring the levels of indicators such as lactic acid, glucose and nitrite. The results showed that the optimum ratio of inoculation of Pediococcus pentosaceus M52 and Lactiplantibacillus pentosus H1 was 2:1 at 1% inoculation, and the physicochemical indicators of the co-inoculated fermented mustard were improved relative to naturally or single strain- inoculated fermented mustard. Non-targeted metabolomics was used to analyze and compare metabolites between naturally fermented and co-inoculated fermented mustard. The largest proportion of metabolites found was carboxylic acid and their derivatives (16.46%), while the second-largest proportion was undefined (11.91%). A total of 206 significant differential metabolites were identified, of which 139 were identified in the cationic mode and 67 in the anionic mode. Among them, amino acid, peptides and peptides analogs, carbohydrates and carbohydrate conjugates, and benzene and substituted derivatives, showed greatest diversity. The significantly up-regulated differential metabolites in co-inoculated fermented mustard included amino acid, organic acid and derivatives, heterocyclic and benzene ring- containing compounds. Improved flavor and nutritional value of the fermented mustard were associated with increased amino acid, organic acid, and aromatic substance levels. Functional analyses showed enrichment of the differential metabolites in various metabolic pathways, involved in ABC transporters, galactose metabolism, phosphotransferase system, biosynthesis of amino acid, nucleotide metabolism, biosynthesis of secondary metabolites and other metabolic pathways. Moreover, nutrients such as vitamin C, adenosine 3'-monophosphate and trans-ferulic acid were significantly increased. These findings clarify the differences in physicochemical properties and metabolic characteristics between naturally fermented and co-inoculated lactic acid bacteria-fermented mustard, providing a reference for the standardized and large-scale production of co-inoculated lactic acid bacteria- fermented vegetables.

细菌生活在营养匮乏的环境时,为了能够适应这种恶劣的环境,细菌自身会产生应急反应.细菌的应急反应至今仍是生物学研究热点之一,实施这一应急反应的是胞内的信号分子(p)ppGpp,其能与RNA聚合酶结合,调控许多细胞过程,包括病原细菌致病过程,可以作为防治动植物细菌性病害的药物靶点.植物病原细菌分布范围很广,能引起植物的许多重要病害发生,对许多农作物造成了重大经济损失.本文综述了植物病原细菌解淀粉欧文氏菌(Erwinia amylovora)、丁香假单胞杆菌(Pseudomcnas syringae)、黑腐果胶杆菌(Pecto-bacterium atrosepticum)、柑橘黄单胞菌柑橘亚种(Xanthomonas citri subsp.citri)和十字花科黑腐病菌(X.campestris pv.campestris,Xcc)中应急反应的研究进展,为全面、深入地了解植物病原细菌的应急反应,有效防治植物细菌性病害提供参考.

Ubiquitination, an important posttranslational modification, participates in virtually all aspects of cellular functions and is reversed by deubiquitinating enzymes (DUBs). Ubiquitin-specific protease 34 (USP34) plays an essential role in cancer, neurodegenerative diseases, and osteogenesis. Despite its functional importance, how USP34 recognizes ubiquitin and catalyzes deubiquitination remains structurally uncharacterized. Here, we report the crystal structures of the USP34 catalytic domain in free state and after binding with ubiquitin. In the free state, USP34 adopts an inactive conformation, which contains a misaligned catalytic histidine in the triad. Comparison of USP34 structures before and after ubiquitin binding reveals a structural basis for ubiquitin recognition and elucidates a mechanism by which the catalytic triad is realigned. Transition from an open inactive state to a relatively closed active state is coupled to a process by which the "fingertips" of USP34 intimately grip ubiquitin, and this has not been reported before. Our structural and biochemical analyses provide important insights into the catalytic mechanism and ubiquitin recognition of USP34.

The surface topological structures of the artificial implants are conducive to induce orientation growth of nerve cells and promote nerve regeneration. However, their effect on long-distance extension of dorsal root ganglion (DRG) axons is still limited and needs further enhancement. In this study, an anisotropic chitosan (CS) micropatterning containing metformin (Me) functionalized CaTiO3 (CTO) nanoparticles (NPs) for regulating DRG behavior was fabricated by micro-molding and biomodification method. The physicochemical properties of CTO nanoparticles as a function of biomodification by poly-dopamine (PDA) and Me were monitored by Zeta (ζ) potential, Fourier Transform infrared spectroscopy (FTIR), X-ray Powder Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Spectroscopy (EDX) analysis, respectively. The morphology, structure, and wettability of the CS micropatterning were characterized. In addition, Atomic Force Microscope (AFM) was used to scan the topological membrane surface to explore its surface profile. The in vitro effect of the micropatterning on DRG axon behavior including morphology, length and orientation was evaluated. The results showed that PDA-modified CTO NPs could load Me effectively and showed considerable stability. The addition of Me functionalized CTO NPs obviously improved the hydrophilicity and roughness of the CS micropatterning. DRG culture showed that the axon extension on the topology followed the arrangement direction of the anisotropic microstructure. Compared with the pure CS micropatterning, the length of the axon extension on the surface of Me-PDA-CTO-CS was significantly improved about 61.1%, indicating an obvious axonal extension promotion effect. Therefore, it is concluded that the Me-PDA-CTO-CS could constrain the direction of axon extension while obviously promoting axon growth, which may be expected to provide a new strategy for repairing peripheral nerve injury (PNI).

教育是最大的民生，关乎国家发展大计，更关乎着百姓的切身利益，其中高等学校教育是国家教育的重要组成部分，承担着为国家输送人才的职责。高等学校教育应努力为国家培养德、智、体、美、劳全面发展的社会主义建设者和接班人，不仅要努力发展学生的智力，提高学生的认知和知识水平，陶冶学生高尚的道德情操，同时也应关注学生的身心发展，应将大学生健康教育作为大学生的主修课程。

Background Mounting evidence has suggested the essential role of long non-coding RNAs (lncRNAs) in a plethora of malignant tumors, including hepatocellular carcinoma. However, the underlyling mechanisms of lncRNAs remain unidentified in HCC. The present work was aimed to explore the regulatory functions and mechanisms of LncRNA LNCAROD in HCC progression and chemotherapeutic response. Methods The expression of LNCAROD in HCC tissues and cell lines were detected by quantitative reverse transcription PCR (qPCR). Cancer cell proliferation, migration, invasion, and chemoresistance were evaluated by cell counting kit 8 (CCK8), colony formation, transwell, and chemosensitivity assays. Methylated RNA immunoprecipitation qRCR (MeRIP-qPCR) was used to determine N6-methyladenosine (m(6)A) modification level. RNA immunoprecipitation (RIP) and RNA pull down were applied to identify the molecular sponge role of LNCAROD for modulation of miR-145-5p via the competing endogenous RNA (ceRNA) mechanism, as well as the interaction between LNCAROD and serine-and arginine-rich splicing factor 3 (SRSF3). The interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) and LNCAROD was also identified by RIP assay. Gain- or-loss-of-function assays were used to identify the function and underlying mechanisms of LNCAROD in HCC. Results We found that LNCAROD was significantly upregulated and predicted a poorer prognosis in HCC patients. LNCAROD upregulation was maintained by increased m(6)A methylation-mediated RNA stability. LNCAROD significantly promoted HCC cell proliferation, migration, invasion, and chemoresistance both in vitro and in vivo. Furthermore, mechanistic studies revealed that pyruvate kinase isoform M2 (PKM2)-mediated glycolysis enhancement is critical for the role of LNACROD in HCC. According to bioinformatics prediction and our experimental data, LNCAROD directly binds to SRSF3 to induce PKM switching towards PKM2 and maintains PKM2 levels in HCC by acting as a ceRNA against miR-145-5p. The oncogenic effects of LNCAROD in HCC were more prominent under hypoxia than normoxia due to the upregulation of hypoxia-triggered hypoxia-inducible factor 1 alpha. Conclusions In summary, our present study suggests that LNCAROD induces PKM2 upregulation via simultaneously enhancing SRSF3-mediated PKM switching to PKM2 and sponging miR-145-5p to increase PKM2 level, eventually increasing cancer cell aerobic glycolysis to participate in tumor malignancy and chemoresistance, especially under hypoxic microenvironment. This study provides a promising diagnostic marker and therapeutic target for HCC patients.

In bacteria, GntR family transcription regulators are the widespread family of transcription factors. Members of this family consist of two functional domains, a conserved N-terminal DNA-binding domain that contains a typical helix-turn-helix (HTH) motif and a C-terminal effector-binding or oligomerization domain. Usually, the amino acid sequences of N-terminal DNA-binding domains are highly conserved, but differ in the C-terminal effector-binding or oligomerization domains. In the past several decades, many GntR family transcription regulators have been characterized in a number of bacteria. These regulators control a variety of cellular processes such as cell motility, glucose metabolism, bacterial resistance, pathogenesis and virulence. In this review, we summarized the discovery, C-terminal domains, biological function and regulation mode of GntR family transcription regulators. This review will help researchers to obtain more knowledge about the functions and mechanisms of the GntR family transcriptional regulatory factors.

Hepatocellular carcinoma (HCC) is the most common malignant tumor worldwide, characterized by insidious onset as well as high incidence, recurrence, metastasis, and mortality rates. At present, there is no effective clinical treatment method except transplantation. The emergence and development of high throughput sequencing technologies in recent years has turned the epigenetics of cancer to spotlight; specifically, RNA methylation modification becomes a much discussed topic recently. RNA methylation modification plays a key role in the occurrence and development of HCC. This article reviews the relationship between different types of RNA methylation modification and HCC progression, which provides a new research direction for exploring the pathogenesis of HCC and developing new diagnostic methods and therapeutic targets.

Abnormal histone modification plays an important role in the occurrence and development of hepatocellular carcinoma (HCC). As an important histone modification pattern, histone methylation is closely related to the occurrence and development of HCC. In recent years, a large number of studies have shown that abnormal histone methylation is involved in the proliferation, invasion, and metastasis of HCC and is related to the prognosis of HCC patients. Enzymes associated with histone methylation play an important role in the histone methylation process. Exploration of the relationship between histone methylation and HCC, and in-depth studies on the pathogenesis of the disease would contribute to the finding of tumor markers and the development of targeted drugs, which is of great significance for the diagnosis, treatment, and prognosis of patients with HCC. This review summarizes the research progress regarding the enzymes involved in histone methylation in HCC.

Transcriptional regulators are key players in pathways that allow bacteria to alter gene expression in response to environmental conditions. However, work to understand how such transcriptional regulatory networks interact in bacterial plant pathogens is limited. Here, in the phytopathogen Xanthomonas campestris, we demonstrate that the global transcriptional regulator HpaR1 influences many of the same genes as another global regulator Clp, including the engXCA gene that encodes extracellular endoglucanase. We demonstrate that HpaR1 facilitates the binding of RNA polymerase to the engXCA promoter. In addition, we show that HpaR1 binds directly to the engXCA promoter. Furthermore, our in vitro tests characterize two binding sites for Clp within the engXCA promoter. Interestingly, one of these sites overlaps with the HpaR1 binding site. Mobility shift assays reveal that HpaR1 has greater affinity for binding to the engXCA promoter. This observation is supported by promoter activity assays, which show that the engXCA expression level is lower when both HpaR1 and Clp are present together, rather than alone. The data also reveal that HpaR1 and Clp activate engXCA gene expression by binding directly to its promoter. This transcriptional activation is modulated as both regulators compete to bind to overlapping sites on the engXCA promoter. Bioinformatics analysis suggests that this mechanism may be used broadly in Xanthomonas campestris pv. campestris (Xcc) and is probably widespread in Xanthomonads and, potentially, other bacteria. Taken together, these data support a novel mechanism of competitive activation by two global regulators of virulence gene expression in Xcc which is probably widespread in Xanthomonads and, potentially, other bacteria.

十字花科黑腐病菌(Xcc8004)中一对双组份系统hpaS/hpaR2在致病过程中有重要作用,以前的研究发现,XC2388的表达可能受XC3669/X C3670的调控.为分析XC2388的功能,本试验采用pK18mob SacB介导的同源双交换的方法构建缺失突变体,对新获得的缺失突变体DM2388的分析发现,XC2388突变后,病原菌对寄主萝卜叶的致病力与野生型相比降低80％,采用PCR扩增XC2388完整的ORF,将新获得的1 349 bp的DNA片段克隆在pLAFR3质粒上,将新获得的重组质粒导入DM2388,发现互补菌株CDM2388的致病力可以恢复至野生型的60％,表明XC2388与致病性相关.以MMX培养基为介质绘制生长曲线,经分析发现突变体的生长严重受阻,在培养基中加入Thr后可以恢复生长,表明DM2388可能是与Thr合成相关的营养缺陷性菌株.

The GntR family transcription regulator HpaR1 identified from Xanthomonas campestris pv. campestris has been previously shown to positively regulate the genes responsible for hypersensitive reaction and pathogenicity and to autorepress its own expression. Here, we demonstrated that HpaR1 is a global regulator that positively regulates diverse biological processes, including xanthan polysaccharide production, extracellular enzyme activity, cell motility and tolerance to various stresses. To investigate the regulatory mechanisms of HpaR1, we began with xanthan polysaccharide production, which is governed by a cluster of gum genes. These are directed by the gumB promoter. Disruption of HpaR1 significantly reduced gumB transcription and an electrophoretic mobility shift assay demonstrated that HpaR1 interacts directly with gumB promoter. DNase I footprint analysis revealed that HpaR1 and RNA polymerase were bound to the sequences extending from -21 to +10 and -41 to +29 relative to the transcription initiation site of gumB, respectively. Furthermore, in vitro transcription assays showed that HpaR1 facilitated the binding of RNA polymerase to gumB promoter, leading to an enhancement of its transcription. These results suggest that HpaR1 regulates gumB transcription via a mechanism similar but different to what was found, until now, to only be used by some MerR family transcription activators.

[目的]稻黄单胞杆菌水稻致病变种Xanthomonas oryzae pv.oryzae(Xoo) PXO99A菌株中PXO_03420基因被注释为编码具有多个LRR的Ⅲ型效应物基因hpaF,本研究旨在明确hpaF基因的功能,为完善Xoo Ⅲ型效应物的研究提供一定的理论基础.[方法]通过同源双交换构建hpaF基因的缺失突变体,并通过表型分析、致病性试验和遗传互补对该基因的功能进行研究.[结果和结论]本研究发现,hpaF基因突变后对水稻日本晴品种的致病力降低了51.81％,减弱了细菌在非寄主植物蓖麻上的过敏反应.而带有hpaF全基因片段的pLAFR3能够恢复hpaF突变体的致病表型,结果表明hpaF基因与水稻白叶枯病菌的致病性相关.

十字花科黑腐病菌(Xanthomonas campestris pv.campestris,简称Xcc)能够产生大量的胞外多糖.胞外多糖商品名又称为黄原胶,具有广泛用途,在食品生产中可作为添加剂使用.为了得到不含黄色素的黄原胶,我们采用转座子EZ-Tn5随机插入诱变的方法对8004菌株进行突变,获得了一株不产黄色素的突变体.通过对突变体的转座子EZ-Tn5插入位点进行分析,发现该突变体是由于编号为XC_ 4097的基因被插入突变后衍生而来.同源性分析表明XC 4097编码一种脂质酰基转移酶,它与脂质的合成有关.采用同源双交换方法构建XC 4097基因的缺失突变体.通过对野生菌、突变体以及功能回补体的表型分析进一步证实了XC 4097基因功能的丧失只影响黑腐病菌黄色素的合成,而不影响细菌生长以及胞外多糖的合成.这为工业上生产无黄色素的黄原胶提供了应用基础.

The bacterial phytopathogen Xanthomonas campestris pv. campestris (Xcc) relies on the hrp (hypersensitive response and pathogenicity) genes to cause disease and induce hypersensitive response (HR). The hrp genes of bacterial phytopathogens are divided into two groups. Xcc hrp genes belong to group II. It has long been known that the group II hrp genes are activated by an AraC-type transcriptional regulator whose expression is controlled by a two-component system (TCS) response regulator (named HrpG in Xcc). However, no cognate sensor kinase has yet been identified. Here, we present evidence showing that the Xcc open-reading frame XC_3670 encodes a TCS sensor kinase (named HpaS). Mutation of hpaS almost completely abolished the HR induction and virulence. Bacterial two-hybrid and protein pull-down assays revealed that HpaS physically interacted with HrpG. Phos-tag (TM) SDS-PAGE analysis showed that mutation in hpaS reduced markedly the phosphorylation of HrpG in vivo. These data suggest that HpaS and HrpG are most likely to form a TCS. We also showed that XC_3669 (named hpaR2), which is adjacent to hpaS and encodes a putative TCS response regulator, is required for full virulence but not HR induction. HpaR2 also physically interacted with HpaS, suggesting that HpaS may also form another TCS with HpaR2.

To investiga te the unknown function of the putative protein of XC_1348 gene of Xanthomonas campestris pv. campestris strain 8004, we used the suicide plasmid pK18mob and pK18mobSacB to construct a nonpolar integrated mutant 1348nk and a marked deletion mutant DM1348Gm by homologous single-crossover and homologous double-crossover integration. Phenotypes studies of these two mutants showed that the mutation on XC_1348 gene did not affect the yield of exopolysaccharides (EPS), the extracellular enzymatic activity, and bacterial motility. However, interestingly, the two mutants showed a great variation in virulence. The reason might be that the two different mutation methods changed the genomic structure of Xcc8004 and the expression of certain genes was affected accordingly. This study not only helps us understand XC_1348 gene preliminarily, but also provides us a basis to improve the site-directed mutation method for further study.

The transcriptional regulator XC_2736(HpaR1) of X.campestris pv.campestris(Xcc) 8004 plays important roles in regulating bacterial diverse biological processes.Previous work showed that this transcriptional regulator might play role on extracellular cellulase.To illustrate the regulatory mechanism,HpaR1 was over expressed,and electrophoretic mobility shift assays(EMSA) were performed using HpaR1 protein and the promoter fragment end XCA-p of XC_0639.Results showed that HpaR1 could specifically bind to the promoter fragment of XC_0639.The reporter plasmid pGUS0639r was constructed by fusing the promoter of XC_0639 with gus gene,and them been introduced into wild type strain 8004 and the HpaR1 mutant DM2736,respectively.The expression level of GUS decreased significantly in the mutant,compared to the wild type background,suggesting HpaR1 positively regulates the expression of XC_0639.Mutation in XC_0639 reduces the cellulose activity greatly in Xcc.The results revealed HpaR1 regulates the cellulase activity by regulating the expression of the cellulase gene XC_0639.This work expends our horizons on the underlying regulatory mechanism and the physiological and biochemical function of HpaR1.

The GntR family is one of the most abundant and widely distributed groups of helix-turn-helix transcriptional regulators in bacteria. Six open reading frames in the genome of the plant pathogen Xanthomonas campestris pv. campestris were predicted to encode GntR regulators. All six of the predicted GntR-encoding genes were individually mutagenized and mutants from five of them were successfully obtained. Plant disease response assays revealed that one, whose product belongs to the YtrA subfamily and has been named HpaR1, is involved in the hypersensitive response (HR) and virulence. Electrophoretic mobility shift assays and in vitro transcription assays revealed that HpaR1 could repress its own transcription level through binding to its promoter sequence, indicating an autoregulatory feedback inhibition mechanism for HpaR1 expression. Promoter-gusA reporter and reverse-transcription polymerase chain reaction analyses revealed that HpaR1 positively and negatively affects the expression of HR and pathogenicity (hrp) genes in host plant and standard media, respectively. Constitutive expression of the key hrp regulator, hrpG, in the hpaR1 mutant could bypass the requirement of HpaR1 for the induction of wild-type HR, suggesting that HpaR1 regulates the expression of hrp genes that encode the type III secretion system via hrpG.

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of the black rot disease of cruciferous plants. Our previous work had demonstrated that XC3814 is required for full virulence and extracellular polysaccharide production. In this work, the reporter plasmid pL3814sac was constructed by fusing the promoter region of XC3814 to the coding region of the gene sacB, and introduced into Xcc wild-type strain 8004. The resulted strain 8004/pL3814sac was mutagenized randomly by the transposon EZ::Tn5, and 3 mutant strains insensitive to sucrose were isolated. One of the mutants was due to the disruption of the open reading frame XC3882, which was assigned to code a hypothetical protein. To verify whether XC3882 has an impact on the expression level of XC3814, the reporter plasmid pGUS3814 was constructed by fusing the promoter region of XC3814 to the coding region of the gusA gene. This construct was introduced into the wild-type strain 8004 and the XC3882 mutant strain 190A10, which was derived from the transposon Tn5gusA5 insertion. The GUS activity, produced by pGUS3814 in the XC3882 mutant background, was reduced by 81.3% compared to that in the wild type background. These results indicate that the expression of XC3814 is influenced by XC3882.