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Antimicrobial and anti-biofilm activity of Polygonum chinense L.aqueous extract against Staphylococcus aureus
2022
Polygonum chinense
Linn. (
Polygonum chinense
L.) is one of the main raw materials of Chinese patent medicines such as Guangdong herbal tea. The increasing antibiotic resistance of
S. aureus
and the biofilm poses a serious health threat to humans, and there is an urgent need to provide new antimicrobial agents. As a traditional Chinese medicine, the antibacterial effect of
Polygonum chinense
L. has been reported, but the antibacterial mechanism of
Polygonum chinense
L.aqueous extract and its effect on biofilm have not been studied in great detail, which hinders its application as an effective antibacterial agent. In this study, the mechanism of action of
Polygonum chinense
L.aqueous extract on
Staphylococcus aureus
(
S. aureus
) and its biofilm was mainly evaluated by morphological observation, flow cytometry and laser confocal experiments. Our findings demonstrate that
Polygonum chinense
L.aqueous extract has a significant bacteriostatic effect on
S. aureus
. The result of growth curve exhibits that
Polygonum chinense
L.aqueous extract presents a significant inhibitory effect against
S. aureus
. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) reveals that
Polygonum chinense
L.aqueous extract exerts a potent destruction of the cell wall of
S. aureus
and a significant inhibitory effect on the formation of
S. aureus
biofilm. In addition, flow cytometry showed the ability of
Polygonum chinense
L.aqueous extract to promote apoptosis by disrupting cell membranes of
S. aureus
. Notably, confocal laser scanning microscopy (CLSM) images illustrated the ability of
Polygonum chinense
L.aqueous to inhibit the formation of
S. aureus
biofilms in a dose-dependent manner. These results suggested that
Polygonum chinense
L.aqueous is a promising alternative antibacterial and anti-biofilm agent for combating infections caused by planktonic and biofilm cells of
S. aureus
.
Journal Article
Correction: Rifampicin and isoniazid resistance not promote fluoroquinolone resistance in Mycobacterium smegmatis
2025
[This corrects the article DOI: 10.1371/journal.pone.0315512.].
Journal Article
Rifampicin and isoniazid resistance not promote fluoroquinolone resistance in Mycobacterium smegmatis
by
Xu, Ge
,
Zhou, Qin
,
Wang, Xiaomin
in
Antibiotics
,
Antitubercular Agents - pharmacology
,
Biology and Life Sciences
2025
The emergence of drug-resistant Tuberculosis (TB) has made treatment challenging. Although fluoroquinolones (FQs) are used as key drugs in the treatment of multidrug-resistant tuberculosis (MDR-TB), the problem of FQs resistance is becoming increasingly serious. Rifampicin (RIF) resistance is considered a risk factor for FQs resistance. The objective of this study was to investigate the impact of RIF and isoniazid (INH) resistance on the FQs resistance in vitro experiment.
FQs resistant strains were selected in vitro from RIF and/or INH resistant Mycobacterium smegmatis (M.sm). The sequencing of the gyrA gene, and the minimum inhibitory concentration (MIC) of FQs (ciprofloxacin, levofloxacin, moxifloxacin and gatifloxacin) were performed for FQs-resistant strains.
A total of 222 FQs-resistant M.sm strains were selected, all of which had the gyrA mutation. Seven gyrA mutations were detected, with mutations at loci 90 and 94 being the most common. There were no differences in FQs resistance developed from RIF and/or INH resistant M.sm. There was a significant difference in the MIC of the gyrA mutant types to FQs. The highest resistance to FQs was observed in the Gly88Cys mutant strains. M.sm with the identical gyrA mutation showed the highest resistance to ciprofloxacin and relatively low resistance to gatifloxacin and moxifloxacin.
In this study, we found no evidence that RIF and/or INH resistance directly affects FQs resistance in M.sm in vitro experiments. Resistance profiles of different gryA mutations to the four FQs drugs were also presented. These findings provide a more comprehensive understanding of FQs resistance.
Journal Article
Expanding ACMG variant classification guidelines into a general framework
by
Liao, Zhuan
,
Génin, Emmanuelle
,
Rebours, Vinciane
in
ACMG guidelines
,
Allele frequency threshold
,
Allelic heterogeneity
2022
Background
The American College of Medical Genetics and Genomics (ACMG)-recommended five variant classification categories (pathogenic, likely pathogenic, uncertain significance, likely benign, and benign) have been widely used in medical genetics. However, these guidelines are fundamentally constrained in practice owing to their focus upon Mendelian disease genes and their dichotomous classification of variants as being either causal or not. Herein, we attempt to expand the ACMG guidelines into a general variant classification framework that takes into account not only the continuum of clinical phenotypes, but also the continuum of the variants’ genetic effects, and the different pathological roles of the implicated genes.
Main body
As a disease model, we employed chronic pancreatitis (CP), which manifests clinically as a spectrum from monogenic to multifactorial. Bearing in mind that any general conceptual proposal should be based upon sound data, we focused our analysis on the four most extensively studied CP genes,
PRSS1
,
CFTR
,
SPINK1
and
CTRC
. Based upon several cross-gene and cross-variant comparisons, we first assigned the different genes to two distinct categories in terms of disease causation: CP-causing (
PRSS1
and
SPINK1
) and CP-predisposing (
CFTR
and
CTRC
). We then employed two new classificatory categories, “predisposing” and “likely predisposing”, to replace ACMG’s “pathogenic” and “likely pathogenic” categories in the context of CP-predisposing genes, thereby classifying all pathologically relevant variants in these genes as “predisposing”. In the case of CP-causing genes, the two new classificatory categories served to extend the five ACMG categories whilst two thresholds (allele frequency and functional) were introduced to discriminate “pathogenic” from “predisposing” variants.
Conclusion
Employing CP as a disease model, we expand ACMG guidelines into a five-category classification system (predisposing, likely predisposing, uncertain significance, likely benign, and benign) and a seven-category classification system (pathogenic, likely pathogenic, predisposing, likely predisposing, uncertain significance, likely benign, and benign) in the context of disease-predisposing and disease-causing genes, respectively. Taken together, the two systems constitute a general variant classification framework that, in principle, should span the entire spectrum of variants in any disease-related gene. The maximal compliance of our five-category and seven-category classification systems with the ACMG guidelines ought to facilitate their practical application.
Journal Article
Analysis of the sulfate permease family in Bursaphelenchus xylophilus in the nematode development and stress adaptation
2025
Pine wilt disease (PWD), caused by the pine wood nematode (PWN)
, poses a significant threat to global pine forests. The sulfate permease (SULP) family is essential for sulfate transport, sulfur assimilation and cellular homeostasis, yet it remains uncharacterized in
. This study aimed to comprehensively identify all members of the SULP family in
and to elucidate their roles in nematode development and stress adaptation.
Through genomic data analysis, we identified 10 members of the SULP family in
and conducted a comprehensive characterization of their physicochemical properties, conserved motifs, protein structures, and gene expression profiles across different developmental stages.
The results revealed Bx-sulps were located on 5 chromosomes of
. Phylogenetic analysis unveiled both conserved and divergent evolutionary patterns of these proteins compared to counterparts in other nematodes. Expression analysis demonstrated upregulation of
during the dauer third-instar larva (D3) stage, suggesting their involvement in stress response and diapause. Moreover, certain Bx-sulps exhibited high expression levels in adult stages, indicating a potential role in reproductive processes.
The study presents the first comprehensive examination of BxSULP family, shed light on its significance in nematode development and stress adaptation. These findings provide the groundwork for further functional investigations and may aid in the development of targeted strategies for managing PWD.
Journal Article
EgLDH as a Novel Target: Design and Preliminary Efficacy Assessment of a DNA Vaccine
2026
(1) Background: Echinococcosis is a significant zoonotic disease that the World Health Organization (WHO) aims to eliminate by 2050. Current drug-based control faces challenges such as drug resistance, highlighting the urgent need to develop vaccines as a supplementary strategy. Although some progress has been made in the study of intermediate host vaccines using antigens such as Eg95, there is still no commercial vaccine available for the definitive host, canines—which are crucial for transmission—and it is not yet suitable for large-scale use. While vaccine studies targeting the key enzyme lactate dehydrogenase (LDH) in parasite energy metabolism remain scarce, they represent a promising area of potential. (2) Methods: The B cell antigen epitopes of LDH were analyzed, and prokaryotic (pET-28a-EgLDH) and eukaryotic (pVAX1-EgLDH) DNA vaccine expression vectors were constructed. After verifying expression and immunogenicity via qRT-PCR and WB, in vitro validation was performed in 293T cells. Mice were immunized with the vaccine and then challenged with the parasite; blood was collected from the orbital sinus, and IgG levels and cytokines were measured by ELISA. Protective effects were assessed through counting liver cysts and histopathological analysis. (3) Results: We constructed the pVAX1-EgLDH plasmid and immunized Kunming (KM) mice. Compared with the PBS control group, the vaccine group showed an 80.95% reduction in liver cysts (Quil-A group: 19.00%). Histopathological analysis indicated no significant liver damage, although the spleens in the vaccine group were smaller. ELISA results demonstrated an increase in total IgG (p < 0.05), and cytokine analysis showed elevated levels of IL-1 (p < 0.01), IL-4, and IL-10 (p < 0.001), whereas IL-5 and IFN-γ showed no significant changes (p > 0.05). (4) Conclusions: The EgLDH DNA vaccine can elicit a specific immune response and significantly reduce cyst burden, providing theoretical basis and data support for its use as a candidate vaccine for the prevention and control of Echinococcosis.
Journal Article
A linear smoothed meshfree method with intrinsic enrichment functions for 2D crack analysis
2022
PurposeThis article aims to develop an accurate and efficient meshfree Galerkin method based on the strain smoothing technique for linear elastic continuous and fracture problems.Design/methodology/approachThis paper proposed a generalized linear smoothed meshfree method (LSMM), in which the compatible strain is reconstructed by the linear smoothed strains. Based on the idea of the weighted residual method and employing three linearly independent weight functions, the linear smoothed strains can be created easily in a smoothing domain. Using various types of basic functions, LSMM can solve the linear elastic continuous and fracture problems in a unified way.FindingsOn the one hand, the LSMM inherits the properties of high efficiency and stability from the stabilized conforming nodal integration (SCNI). On the other hand, the LSMM is more accurate than the SCNI, because it can produce continuous strains instead of the piece-wise strains obtained by SCNI. Those excellent performances ensure that the LSMM has the capability to precisely track the crack propagation problems. Several numerical examples are investigated to verify the accurate, convergence rate and robustness of the present LSMM.Originality/valueThis study provides an accurate and efficient meshfree method for simulating crack growth.
Journal Article
Frameshift coding sequence variants in the LPL gene: identification of two novel events and exploration of the genotype–phenotype relationship for variants reported to date
2023
Background
Lipoprotein lipase (LPL) is the rate-limiting enzyme for triglyceride hydrolysis. Homozygous or compound heterozygous
LPL
variants cause autosomal recessive familial chylomicronemia syndrome (FCS), whereas simple heterozygous
LPL
variants are associated with hypertriglyceridemia (HTG) and HTG-related disorders.
LPL
frameshift coding sequence variants usually cause complete functional loss of the affected allele, thereby allowing exploration of the impact of different levels of LPL function in human disease.
Methods
All exons and flanking intronic regions of
LPL
were Sanger sequenced in patients with HTG-related acute pancreatitis (HTG-AP) or HTG-AP in pregnancy. Previously reported
LPL
frameshift coding sequence variants were collated from the Human Gene Mutation Database and through PubMed keyword searching. Original reports were manually evaluated for the following information: zygosity status of the variant, plasma LPL activity of the variant carrier, disease referred for genetic analysis, patient’s age at genetic analysis, and patient’s disease history. SpliceAI was employed to predict the potential impact of collated variants on splicing.
Results
Two novel rare variants were identified, and 53 known
LPL
frameshift coding sequence variants were collated. Of the 51 variants informative for zygosity, 30 were simple heterozygotes, 12 were homozygotes, and 9 were compound heterozygotes. Careful evaluation of the 55 variants with respect to their clinical and genetic data generated several interesting findings. First, we conclude that 6–7% residual LPL function could significantly delay the age of onset of FCS and reduce the prevalence of FCS-associated syndromes. Second, whereas a large majority of
LPL
frameshift coding sequence variants completely disrupt gene function through their \"frameshift\" nature, a small fraction of these variants may act wholly or partly as \"in-frame\" variants, leading to the generation of protein products with some residual LPL function. Third, we identified two candidate
LPL
frameshift coding sequence variants that may retain residual function based on genotype–phenotype correlation or SpliceAI-predicted data.
Conclusions
This study reported two novel
LPL
variants and yielded new insights into the genotype–phenotype relationship as it pertains to
LPL
frameshift coding sequence variants.
Journal Article
Significant but partial lipoprotein lipase functional loss caused by a novel occurrence of rare LPL biallelic variants
2024
Background
Lipoprotein lipase (LPL) plays a crucial role in triglyceride hydrolysis. Rare biallelic variants in the
LPL
gene leading to complete or near-complete loss of function cause autosomal recessive familial chylomicronemia syndrome. However, rare biallelic
LPL
variants resulting in significant but partial loss of function are rarely documented. This study reports a novel occurrence of such rare biallelic
LPL
variants in a Chinese patient with hypertriglyceridemia-induced acute pancreatitis (HTG-AP) during pregnancy and provides an in-depth functional characterization.
Methods
The complete coding sequences and adjacent intronic regions of the
LPL
,
APOC2
,
APOA5
,
LMF1
, and
GPIHBP1
genes were analyzed by Sanger sequencing. The aim was to identify rare variants, including nonsense, frameshift, missense, small in-frame deletions or insertions, and canonical splice site mutations. The functional impact of identified
LPL
missense variants on protein expression, secretion, and activity was assessed in HEK293T cells through single and co-transfection experiments, with and without heparin treatment.
Results
Two rare
LPL
missense variants were identified in the patient: the previously reported c.809G > A (p.Arg270His) and a novel c.331G > C (p.Val111Leu). Genetic testing confirmed these variants were inherited biallelically. Functional analysis showed that the p.Arg270His variant resulted in a near-complete loss of LPL function due to effects on protein synthesis/stability, secretion, and enzymatic activity. In contrast, the p.Val111Leu variant retained approximately 32.3% of wild-type activity, without impacting protein synthesis, stability, or secretion. Co-transfection experiments indicated a combined activity level of 20.7%, suggesting no dominant negative interaction between the variants. The patient’s post-heparin plasma LPL activity was about 35% of control levels.
Conclusions
This study presents a novel case of partial but significant loss-of-function biallelic
LPL
variants in a patient with HTG-AP during pregnancy. Our findings enhance the understanding of the nuanced relationship between
LPL
genotypes and clinical phenotypes, highlighting the importance of residual LPL function in disease manifestation and severity. Additionally, our study underscores the challenges in classifying partial loss-of-function variants in classical Mendelian disease genes according to the American College of Medical Genetics and Genomics (ACMG)’s variant classification guidelines.
Journal Article
The East Asian-specific LPL p.Ala288Thr (c.862G > A) missense variant exerts a mild effect on protein function
2023
Background
Lipoprotein lipase (LPL) is the key enzyme responsible for the hydrolysis of triglycerides. Loss-of-function variants in the
LPL
gene are associated with hypertriglyceridemia (HTG) and HTG-related diseases. Unlike nonsense, frameshift and canonical GT-AG splice site variants, a pathogenic role for clinically identified
LPL
missense variants should generally be confirmed by functional analysis. Herein, we describe the clinical and functional analysis of a rare
LPL
missense variant.
Methods
Chinese patients with HTG-associated acute pancreatitis (HTG-AP) were screened for rare nonsense, frameshift, missense or canonical GT-AG splice site variants in
LPL
and four other lipid metabolism-related genes (
APOC2
,
APOA5
,
GPIHBP1
and
LMF1
) by Sanger sequencing. The functional consequences of the
LPL
missense variant of interest were characterized by in vitro expression in HEK-293T and COS-7 cells followed by Western blot and LPL activity assays.
Results
Five unrelated HTG-AP patients were found to be heterozygous for a rare East Asian-specific
LPL
missense variant, c.862G > A (p.Ala288Thr). All five patients were adult males, and all were overweight and had a long history of alcohol consumption. Transfection of
LPL
wild-type and c.862G > A expression vectors into two cell lines followed by Western blot analysis served to exclude the possibility that the p.Ala288Thr missense variant either impaired protein synthesis or increased protein degradation. Contrary to a previous functional study that claimed that p.Ala288Thr had a severe impact on LPL function (reportedly having 36% normal activity), our experiments consistently demonstrated that the variant had a comparatively mild effect on LPL functional activity, which was mediated through its impact upon LPL protein secretion (~ 20% reduced secretion compared to wild-type).
Conclusions
In this study, we identified the East Asian-specific
LPL
c.862G > A (p.Ala288Thr) missense variant in five unrelated HTG-AP patients. We demonstrated that this variant exerted only a relatively mild effect on LPL function in two cell lines. Heterozygosity for this
LPL
variant may have combined with alcohol consumption to trigger HTG-AP in these patients.
Journal Article