Publications by authors named "Liu Guangjin"

Article Synopsis
  • Streptococcus agalactiae (S. agalactiae) is a type of bacteria known for causing infections, primarily studied in humans and some animals, but a specific strain named CFFB was found in a healthy Sichuan golden snub-nosed monkey.
  • The CFFB strain was closely related to human strains genetically, particularly identified as serotype III, ST19, indicating a possible link or common origin with human infections.
  • Testing showed that CFFB had lower virulence and antibiotic resistance compared to human strains, but it still caused some fatalities in lab mice, and certain genetic features suggested it might have originated from human S. agalactiae.
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Aims: is one of the major anaerobic pathogen causing food poisoning and animal enteritis. With the rise of antibiotic resistance and the restrictions of the use of antibiotic growth promoting agents (AGPs) in farming, enteritis and food contamination have become more common. It is time-consuming and labor-intensive to confirm the detection by standard culture methods, and it is necessary to develop on-site rapid detection tools.

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() is a zoonotic pathogen with multiple serotypes, and thus, multivalent vaccines generating cross-protection against infections are urgently needed to improve animal welfare and reduce antibiotic abuse. In this study, we established a systematic and comprehensive epitope prediction pipeline based on immunoinformatics. Ten candidate epitopes were ultimately selected for building the multi-epitope vaccine (MVSS) against infections.

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  • - The study synthesized novel flavonol alkaloids from green tea through thermal reactions of myricetin, quercetin, and kaempferol, identifying them in specific green tea cultivars using advanced chromatography and mass spectrometry techniques.
  • - The structural analysis of these compounds was conducted using 1D and 2D NMR spectroscopies, uncovering their potential therapeutic effects against Alzheimer's disease.
  • - One particular compound showed a strong binding affinity to amyloid β, significantly improving lifespan and neuroprotection in a transgenic worm model, indicating its potential health benefits.
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The arginine deiminase system (ADS) has been identified in various bacteria and functions to supplement energy production and enhance biological adaptability. The current understanding of the regulatory mechanism of ADS and its effect on bacterial pathogenesis is still limited. Here, we found that the XRE family transcriptional regulator XtrSs negatively affected virulence and significantly repressed ADS transcription when the bacteria were incubated in blood.

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To address the growing health threat posed by drug-resistant pathogenic microorganisms, the development of novel antimicrobial medications with multiple mechanisms of action is in urgent demand. With traditional antibacterial drug resources challenging to push forward, developing new antibacterial drugs has become a hot spot in biomedical research. In this study, we tested the antibacterial activity of 119 phenanthridine derivatives via the antibacterial assay and obtained 5 candidates.

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  • The LuxS quorum sensing system helps bacteria communicate with each other, playing a key role in their survival, particularly in macrophages.
  • This study showed that when the luxS gene is deleted, the bacteria (Streptococcus agalactiae) struggle to survive inside macrophages due to decreased transcription of the fruRKI operon, important for metabolism.
  • The researchers found that luxS doesn’t directly bind to the fruRKI promoter but instead influences its expression by modifying the interaction of a regulatory protein (CcpA) with the promoter region, revealing a new aspect of how bacteria evade the immune response.
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  • Prophages significantly influence the transfer of traits like virulence and antimicrobial resistance genes, although their role in the latter is still debated.
  • SMphages, a common type of prophage in Streptococcus, carry 25 antimicrobial resistance genes, making them resistant to ten drug classes, including critical vancomycin and oxazolidinone antibiotics.
  • These prophages integrate into bacterial chromosomes, can be excised when induced, and transfer rapidly via high-frequency conjugation, contributing to the spread of antimicrobial resistance within Streptococcus species.
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Objective: Clostridium perfringens is one of most important bacterial pathogens in the poultry industry and mainly causes necrotizing enteritis (NE). This pathogen and its toxins can cause foodborne diseases in humans through the food chain. In China, with the rise of antibiotic resistance and the banning of antibiotic growth promoters (AGPs) in poultry farming, food contamination and NE are becoming more prevalent.

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Epigallocatechin-3--(4--methyl)gallate (EGCG4″Me) in possesses numerous beneficial biological activities. However, the germplasm rich in EGCG4″Me and the -methyltransferase responsible for EGCG4″Me biosynthesis are poorly understood. Herein, the content of EGCG3″Me and EGCG4″Me in the shoots of 13 cultivars was analyzed to demonstrate that EGCG4″Me is characteristically accumulated in the "GZMe4" cultivar but not in the other 12 cultivars.

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Source contributions and regional transport of maximum daily average 8-h (MDA8) O during a high O month (June 2019) in Henan province in central China are explored using a source-oriented Community Multiscale Air Quality (CMAQ) model. The monthly average MDA8 O exceeds ∼70 ppb in more than half of the areas and shows a clear spatial gradient, with lower O concentrations in the southwest and higher in the northeast. Significant contributions of anthropogenic emissions to monthly average MDA8 O concentrations of more than 20 ppb are predicted in the provincial capital Zhengzhou, mostly due to emissions from the transportation sector (∼50%) and in the areas in the north and northeast regions where industrial and power generation-related emissions are high.

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(Group B , GBS) is a multi-host pathogen, even causing life-threatening infections in newborns. Vaccination with GBS crossed serotypes vaccine is one of the best options for long-term infection control. Here we built a comprehensive epitope-prediction workflow pipeline to design a multivalent ultiepitope-based subunit accine containing 11 epitopes against (MVSA).

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Air pollution in Henan province is serious and is significantly impacted by pollution transmission and interactions with surrounding areas. The emission sources in 18 cities in Henan province were labeled and applied to the WRF-CMAQ traceability model for simulation in January, April, July, and October of 2017. The pollutant distribution results showed that due to the combined influence of emissions and meteorology, the concentrations of PM, NO, and SO in Henan province were the highest in winter and the lowest in summer.

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  • Serotype 2 (SS2) is a zoonotic pathogen linked to diseases in pigs and cases of severe human illness, specifically streptococcal toxic shock syndrome.
  • The study identified an RNA-binding protein (RbpA) with an S1 domain that enhances SS2's ability to adhere to host cells and increases its pathogenicity.
  • A proteomic analysis revealed 145 differentially expressed proteins, including key virulence factors, and demonstrated that RbpA influences gene expression through various post-transcriptional mechanisms, shedding light on bacterial pathogenicity.
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The clustered regularly interspaced palindromic repeat (CRISPR)-associated (Cas) system functions classically as a prokaryotic defense system against invading mobile genetic elements, such as phages, plasmids, and viruses. Our previous study revealed that CRISPR deletion caused increased transcription of capsular polysaccharide (CPS) synthesis-related genes and severely attenuated virulence in the hypervirulent piscine Streptococcus agalactiae strain GD201008-001. Here, we found that CRISPR deficiency resulted in reduced adhesion, invasion, and biofilm formation abilities in this strain by upregulating the production of CPS.

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Streptococcus suis is an important emerging zoonosis that causes economic losses in the pig industry and severe threats to public health. Transcriptional regulators play essential roles in bacterial adaptation to host environments. In this study, we identified a novel XRE family transcriptional regulator in S.

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Article Synopsis
  • Streptococcal infections are common in both humans and animals, and the rise of multidrug-resistant strains has led to the need for alternative treatments to antibiotics.
  • A novel endolysin called Ply0643, derived from a specific bacteriophage, shows strong antibacterial effects against 66 different Streptococcus strains and is effective in a wide range of temperatures and pH levels.
  • In animal studies, Ply0643 demonstrated significant protective effects against severe bacterial infections and reduced inflammation in mice, indicating its potential as a new treatment for streptococcal infections.
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The clustered regularly interspaced palindromic repeats (CRISPR)-Cas (CRISPR-associated) system is a prokaryotic defence against invading mobile genetic elements, such as bacteriophages or exogenous plasmids. Beyond this, this system has been shown to play an important role in controlling the virulence of some bacterial pathogens. strain GD201008-001, a causative agent of septicemia and meningitis in tilapia, contains a single type II CRISPR-Cas system with Cas9 as a signature protein.

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Streptococcus agalactiae (GBS) is an important pathogen that has increasingly received attention for its role in invasive infections and its broad host range. Research on the regulation of gene expression could illuminate GBS pathogenesis. We previously identified a novel transcriptional regulator XtgS, which is a negative regulator of GBS pathogenicity.

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Streptococcus suis (S. suis) is an important zoonotic pathogen that causes septicaemia, meningitis and streptococcal toxic shock-like syndrome in its host, and recent studies have shown that S. suis could be competent for natural genetic transformation.

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Porcine epidemic diarrhea virus (PEDV) has become increasingly problematic around the world, not only for its hazards to livestock but also due to the possibility that it is a zoonotic disease. Although vaccine therapy has made some progress toward PEDV control, additional effective therapeutic strategies against PEDV are needed, such as the development of chemotherapeutic agents. The aim of this work was to identify novel anti-PEDV agents by designing and synthesizing a series of phenanthridine derivatives.

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Streptococcus agalactiae is a contagious pathogen that causes bovine mastitis worldwide, resulting in considerable economic losses. In this study, we isolated 42 S. agalactiae strains in 379 milk samples from cows with subclinical mastitis on 15 dairy farms in 12 Chinese provinces.

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The serotype 2 (SS2) is a significant zoonotic pathogen that is responsible for various swine diseases, even causing cytokine storms of Streptococcal toxic shock-like syndromes amongst human. Cell wall anchoring proteins with a C-terminal LPxTG are considered to play vital roles during SS2 infection; however, their exporting mechanism across cytoplasmic membranes has remained vague. This study found that YSIRK-G/S was involved in the exportation of LPxTG-anchoring virulence factors MRP and SspA in virulent SS2 strain ZY05719.

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Porcine extraintestinal pathogenic Escherichia coli (ExPEC) is occurring with increasing frequency in China, and leads to significant economic and welfare costs in the swine industry. The underlying mechanisms of porcine ExPEC in blood colonization during systematic infection is poorly understood. Here we measured the gene expression of porcine ExPEC in infected animal bloodstream in vivo and fresh swine blood in vitro.

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