Biomedical subjects

Xiaolin Liu

Publications and source records attributed to Xiaolin Liu.

10 recordsLinked to original sources

PubMed2026

The transcriptional regulator CasR controls mycobacterial antioxidant defense and biofilm formation via multiple direct targets.

AIMS: The antioxidant defense system of Mycobacterium tuberculosis is critical for pathogenicity and persistence within macrophages, yet the regulatory networks remain poorly understood. This study aims to elucidate the molecular mechanism by which the transcription factor CasR regulates antioxidant defense in mycobacteria through delineation of the regulatory axis linking CasR activity, target gene expression, and the antioxidant phenotype. METHODS AND RESULTS: Using Mycobacterium smegmatis as a model organism, we demonstrate that overexpression of CasR renders the bacteria significantly susceptible to hydrogen peroxide. Electrophoretic mobility shift assay (EMSA) and β-galactosidase reporter analyses reveal that CasR directly binds and represses the promoter of cyp144, an uncharacterized cytochrome P450-encoding gene. Deletion of casRMsmreduces biofilm formation, consistent with the expected derepression of cyp144Msm, a gene that negatively regulates both biofilm and oxidative stress tolerance. EMSA and β-galactosidase activity assays also demonstrate that CasR negatively regulates antioxidant gene katGI, suggesting that CasR exerts a broader, global regulatory role within the mycobacterial antioxidant defense network. Furthermore, we identify isoleucine 18 as a critical residue for the DNA-binding and regulatory function of CasR. CONCLUSION: This study establishes CasR as a pleiotropic transcriptional regulator that directly controls multiple antioxidant genes, including cyp144 and katGI, in mycobacteria. We report a previously unrecognized role for a cytochrome P450 family member in suppressing bacterial antioxidant capacity, as cyp144 overexpression reduces biofilm formation. These findings provide a valuable reference for further investigation into mycobacterial antioxidant mechanisms and identify CasR and Cyp144 as potential targets for the development of anti-tuberculosis drugs.

Biofilms↗

PubMed2006

Association of interferon-gamma gene haplotype in the Chinese population with hepatitis B virus infection.

In general, cytokines encoded by different genes of human genome might strongly influence host cell-mediated immune responses, which play an important role in the clearance of virus by the infected host. Interferon gamma (IFN-gamma) produced by T lymphocytes and natural killer cells plays an essential role in affecting cellular immune responses. A functional study demonstrated that two single nucleotide polymorphisms located in the IFN-gamma gene intron (at positions +874 and +2109) were involved in its transcriptional regulation. The aim of this study was to evaluate whether IFN-gamma gene polymorphisms or its haplotypes might be associated with predisposition to hepatitis B virus (HBV) infection in the Chinese population. The study included 181 cases with HBV infection and 272 gender, age-matched healthy controls. All genotyping were identified by polymerase chain reaction in association with the measurement of amplification refractory mutation system. A significant difference was observed between case and control groups. The frequency of +874A allele was significantly higher in patients than in controls (OR = 2.25, 95%CI = 1.69-2.99, P < 0.0001). However, no significant difference was found in the allelic frequencies of IFN-gamma +2109A/G between cases and controls (P > 0.05). By haplotype analysis, the frequency of haplotype AG (+874A and +2109G) revealed a significant difference in the cases in comparison to controls (P < 0.0001). Multiple logistic regression analysis showed that individuals possessing haplotype AG had an increased likelihood of HBV infection (OR = 8.14, 95%CI = 4.98-13.30). Our results suggest that haplotype AG containing +874A and +2109G may be a crucial risk factor of genetic susceptibility to HBV infection in the Chinese population.

Adolescent↗

PubMed2006

[Production and application of bio-derived scaffold in peripheral nerve].

OBJECTIVE: To comment on the recent advances of production and application of the bio-derived scaffold in the tissue engineered peripheral nerve. METHODS: The recent articles were systematically analyzed, and then the production methods of the bio-derived scaffold and its application to the tissue engineered peripheral nerve were evaluated and prospected. RESULTS: Biological tissues were processed by some methods to produce the bio-derived materials. These materials could maintain the structure and components of the tissues. Moreover; the immunogenicity of these materials was reduced. CONCLUSION: Application of the bio-derived materials is a trend in the fabricating scaffold of the tissue engineered peripheral nerve.

Biocompatible Materials↗

PubMed2005

[Cluster analysis on the temporal dynamics of arthropod community in a plum orchard].

In this paper, twelve investigations were conducted on the structural feature of arthropod community in a plum orchard, and a cluster analysis was made on the temporal dynamics of the community. The total community could be clustered into 5 clusters (D = 0.2000), i.e., that in March, in June, in July, in November, and in other months. The natural enemy and pest-neutral sub-communities could be also clustered into 5 clusters, respectively. For natural enemy sub-community, the clusters (D = 0.2000) were that in March, in July, in August, in September and October, and in other months, and for pest-neutral sub-community, they (D = 0.1000) were that in April, in July, in June, in November, and in other months. The results of cluster analysis partly reflected the seasonal differences of total community and sub-communities, while the temporal overlaps of cluster results reflected the complexity of community structure. Based on the optimization cut-apart, both the total community and the sub-communities were divided into 5 stages, i.e., 6 April as the first stage, 27 April to 8 June as the second stage, 27 June to 27 August as the third stage, 21 September to 19 October as the forth stage, and 22 November as the fifth stage.

Animals↗

PubMed2005

[Geostatistics analysis on spatial patterns of Myzus persicae and Erigonidium graminicola in plum orchard].

Investigations on the spatial construction and distribution of Myzus persicae and Erigonidium graminicola in a plum orchard were conducted from March 2003 to November 2003. The results indicated that the semivariogram of Myzus persicae could be described by spherical model, except on June 27 and November 22, which should be described by lined model, and that of Erigonidium graminicola could be described by spherical model, except on May 21, May 31, October 19 and November 22, which should be described by lined model. It could be concluded that the amount and spatial distribution of Erigonidium graminicola was closely related to those of Myzus persicae.

Animals↗

PubMed2005

[Spatial distribution pattern and space dependence of Contarinia sp. and Erigonidium graminicola in jujube orchard].

With the principles and methodologies of geostatistics, this paper studied the spatial structure and space dependence of Contarinia sp. and its natural enemy Erigonidium graminicola in a jujube orchard at different date. The results indicated that the semivariogram of Contarinia sp. on 8 June, 27 August and 19 October could be described by spherical model, showing an aggregated spatial distribution with the ranges of spatial dependence being 26.3, 7.8 and 22.0 m, and the degrees of spatial dependence being 88.05%, 85.77% and 87.58%, respectively. The semivariogram of Erigonidium graminicola could be also described by spherical model, showing an aggregated distribution with the ranges of spatial dependence being 28.3, 22.5 and 22.2 m, and the degrees of spatial dependence being 90.09%, 87.96% and 85.72%, respectively. It is suggested that Erigonidium graminicola is the dominant natural enemy against Contarinia sp. population in the examined jujube orchard.

Animals↗

PubMed2002

Spin filtering with curve windows for interferometric fringe patterns.

Filtering off noise from fringe patterns is important for the processing and analysis of interferometric fringe patterns. Spin filters proposed by the author have been proven to be effective in filtering off noise without blurring and distortion to fringe patterns with small fringe curvature. But spin filters still have problems processing fringe patterns with large fringe curvature. We develop a new spin filtering with curve windows that is suitable for all kinds of fringe pattern regardless of fringe curvature. The experimental results show that the new spin filtering provides optimal results in filtering off noise without distortion of the fringe features, regardless of fringe curvature.

Journal Article↗

PubMed2002

[Effects of ultraviolet(UV-BC) radiation stress on blade visible injury of forty-seven plants].

The effect of simulated ultraviolet (UV-BC) radiation stress on the area of foliar injury and chlorophyll content of forty-seven garden plants were examined with leaf. The result shows that change range of area of foliar injury and chlorophyll content was positively correlated with UV-BC radiation dose [radiant intensity(Tn) x radiant time(d)]. The injury threshold values of forty-seven plants were established. The UV-BC radiation resistance of plants was put in order by injury values of leaves.

Chlorophyll↗

PubMed2002

Study in vitro of populating autogenous Schwann cells into chemical extracted allogenous nerve.

OBJECTIVE: To look for an ideal substance to repair large gap of nerve defect after injury by culture of Schwann cells (Scs) and preparation of acellular allogenous nerve grafts (ANG) with chemical extraction. METHODS: The double adhesion culture and Arab-c to prohibit the fibroblast growth were used to achieve high-purified Scs. Triton-x-100 and sodium deoxycholate were used to achieve ANG. Finally the Scs were microinjected into the acellural nerve grafts and cultured in vitro. The consequence was analysed. RESULTS: High purified Scs and ANG were acquired, which could integrate each other well. Scs could survive and transfer to aline in vitro. CONCLUSIONS: Populating Scs into chemical extracted ANG may be an ideal substance to repair the large gap of nerve defect after injury.

Animals↗

PubMed2002

[Stress effects of simulant acid rain on three woody plants].

Osmanthus fragrana, Chimonanthus praecox and Prunus persica were used as materials to investigate the effect of simulant acid rain on chlorophyll (Chl) content, cell membrane permeability(L%), the content of proline (Pro) and malondialdehyde (MDA) in three woody plants with different resistance, and effects of the light and dark conditions on acid rain injury. The results showed that the change degree of four kinds of physiological and biochemical indexes for these woody plants was as sequence: Osmanthus fragrana > Chimonanthus praecox > Prunus persica. The change of chlorophyll content in these woody plants was not obviously when acid rain stress was influenced by the light and dark.

Acid Rain↗