Biomedical subjects

Xuesong Li

Publications and source records attributed to Xuesong Li.

11 recordsLinked to original sources

PubMed2026

Biocontrol effect of a solid-state fermentation-derived extract mixture of Trichoderma asperellum on sunflower Sclerotinia rot and associated host defense responses.

Sclerotinia disease is a destructive fungal disease of sunflowers, soybeans, and other economically important crops, causing substantial yield loss and quality deterioration. Long-term reliance on dose-dependent broad-spectrum fungicides is constrained by resistance risks and potential environmental burdens, creating tension with the sustainability goal of "reducing pesticide use while improving efficacy." Here, we explore a Trichoderma spp.-based microbial disease management strategy. Whole-genome sequencing of Trichoderma asperellum TCS007 isolated from Antarctic marine sediments, coupled with genome mining, predicted diverse biosynthetic gene clusters putatively associated with siderophores, polyketides, nonribosomal peptides, and terpenoids; the corresponding metabolites are not chemically confirmed and require further validation. Using a solid-state fermentation workflow, we prepared a fermentation-derived extract mixture (TCS007-SSF-Ex). In vitro assays showed dose-dependent inhibition of Sclerotinia sclerotiorum by TCS007-SSF-Ex (EC50 = 1.252 mg/L), and microscopy revealed cellular damage-consistent changes, including organelle disruption and plasmolysis. Pathogen transcriptomic and metabolism-related analyses indicated broad perturbations in organelle biogenesis and metabolic processes, with significant alterations in pathways associated with succinate, D-glucose, and phenylacetate; these results are consistent with growth inhibition and reduced pathogenicity, but specific molecular targets and causal links remain to be validated. In vivo, under certain application conditions, triple applications increased APX activity (+492.5%) and β-1,3-glucanase activity (+419.6%). Collectively, this work supports a "pathogen suppression-host defense induction" framework and facilitates subsequent identification of active components and mechanistic validation.IMPORTANCESclerotinia diseases cause recurrent and economically important losses in oilseed crops, while long-term fungicide use is constrained by resistance risks and environmental burdens. Trichoderma-based biocontrol is a promising complementary strategy, yet evidence supporting metabolite-containing Trichoderma-derived preparations as immune elicitors remains less consolidated than that for living inoculants, and scalable production routes are still needed. Here, we examine an Antarctic marine sediment-derived strain, Trichoderma asperellum TCS007, and a solid-state fermentation (SSF)-derived extract mixture (TCS007-SSF-Ex) produced via solid-state fermentation. We combine in vitro antifungal assays, pathogen ultrastructural observations, and correlative omics analyses with in vivo measurements of sunflower defense enzymes (APX and β-1,3-glucanase) to evaluate a "pathogen suppression-host defense induction" framework. Our findings support the potential of SSF-derived Trichoderma metabolite mixtures for greener management of Sclerotinia disease and provide a foundation for future chemical identification of active components and mechanistic validation.

Ascomycota↗

PubMed2025

Spatial-Temporal Diversity of Extrachromosomal DNA Shapes Urothelial Carcinoma Evolution and Tumor-Immune Microenvironment.

Extrachromosomal DNA (ecDNA) presents a promising target for cancer therapy; however, its spatial-temporal diversity and influence on tumor evolution and the immune microenvironment remain largely unclear. We apply computational methods to analyze ecDNA from whole-genome sequencing data of 595 urothelial carcinoma (UC) patients. We demonstrate that ecDNA drives clonal evolution through structural rearrangements during malignant transformation and recurrence of UC. This supports a model wherein tumors evolve via the selective expansion of ecDNA-bearing cells. Through multi-regional sampling of tumors, we demonstrate that ecDNA contributes to the evolution of multifocality and increased intratumoral heterogeneity. EcDNA is present in 36% of UC tumors and correlates with an immunosuppressive phenotype and poor prognosis. Single-cell RNA sequencing analyses reveal that ecDNA+ malignant cells exhibit diminished expression of major histocompatibility complex class I molecules, enabling them to evade T-cell immunity. Finally, we show that sequencing of urinary sediment-derived DNA has excellent specificity in detecting ecDNA.

Journal Article↗

PubMed2006

Comparative proteomics of rat liver and Morris hepatoma 7777 plasma membranes.

Plasma membranes from normal rat liver and hepatocellular carcinoma Morris hepatoma 7777 were selectively solubilized by use of different reagents. After selective solubilization, proteins were identified by nano-HPLC-electrospray ionization tandem mass spectrometry (LC-ESI MS/MS). Using simple software, the patterns of proteins identified in membrane solubilizates from liver and hepatoma were compared. Proteins identified in Morris hepatoma 7777 and not in the corresponding membrane solubilizate from liver, mostly members of the annexin and heat shock protein families, are discussed as potential candidate markers for hepatocellular carcinomas.

Amino Acid Sequence↗

PubMed2006

Multifunctional composites using reinforced laminae with carbon-nanotube forests.

Traditional fibre-reinforced composite materials with excellent in-plane properties fare poorly when out-of-plane through-thickness properties are important. Composite architectures with fibres designed orthogonal to the two-dimensional (2D) layout in traditional composites could alleviate this weakness in the transverse direction, but all of the efforts so far have only produced limited success. Here, we unveil an approach to the 3D composite challenge, without altering the 2D stack design, on the basis of the concept of interlaminar carbon-nanotube forests that would provide enhanced multifunctional properties along the thickness direction. The carbon-nanotube forests allow the fastening of adjacent plies in the 3D composite. We grow multiwalled carbon nanotubes on the surface of micro-fibre fabric cloth layouts, normal to the fibre lengths, resulting in a 3D effect between plies under loading. These nanotube-coated fabric cloths serve as building blocks for the multilayered 3D composites, with the nanotube forests providing much-needed interlaminar strength and toughness under various loading conditions. For the fabricated 3D composites with nanotube forests, we demonstrate remarkable improvements in the interlaminar fracture toughness, hardness, delamination resistance, in-plane mechanical properties, damping, thermoelastic behaviour, and thermal and electrical conductivities making these structures truly multifunctional.

Journal Article↗

PubMed2006

Use of short monolithic columns for isolation of low abundance membrane proteins.

Convective interaction media (CIM) monoliths provide a stationary phase with a high binding capacity for large molecules and are capable of high flow rates at a very low pressure drop. Used as anion- and cation-exchangers or with affinity ligands such as antibodies, these columns have the potential for processing large volumes of complex biological mixtures within a short time. In the present report, monoclonal antibodies against several rat liver plasma membrane proteins were bound and cross-linked to protein A or protein G CIM affinity columns with a bed volume of only 60 microL. Antigens recognized by bound antibodies and co-eluting (interacting) proteins were rapidly isolated in a single step from either total plasma membrane extracts or subfractions isolated using anion-exchange CIM disk-shaped columns. The isolated antigens and co-eluting proteins were subsequently identified by immunoblot or by LC-MS/MS.

Animals↗

PubMed2006

Identification of members of the annexin family in the detergent-insoluble fraction of rat Morris hepatoma plasma membranes.

For proteomic analysis, plasma membranes of rat hepatocellular carcinoma Morris hepatoma 7777 were selectively solubilized according to the previously developed method [D. Josic, K. Zeilinger, Methods Enzymol. 271 (1996) 113-134]. If the Triton X100 insoluble pellet is subsequently extracted, several proteins can be solubilized. These proteins can be classified in two groups according to their molecular size. The proteins with apparent molecular weights in SDS-PAGE between 70 and 75 kDa belong to the first group. Smaller proteins, with apparent molecular weights between 30 and 45 kDa, are members of the second group. The main protein of higher molecular weight was also found in the Triton X100 insoluble extract from normal rat liver plasma membranes. This protein was identified as Annexin A6. The proteins from the second group are practically absent in the Triton X100 insoluble extract from rat liver. These proteins are present in relatively high concentrations in plasma membranes of Morris hepatoma 7777. Both groups of detergent-insoluble proteins from Morris hepatoma 7777 were further analyzed with SELDI-TOF and LC electrospray ionization mass spectrometry. From the first group, Annexin A6, together with two other integral plasma membrane proteins, was identified. In the second group of proteins with apparent molecular weights between 30 and 45kDa, further members of the annexin family, Annexins A1, A2, A4, A5 and A7 were identified. The possible role of these low molecular size annexins as potential cancer biomarkers is discussed.

Amino Acid Sequence↗

PubMed2006

Use of magnetic beads with immobilized monoclonal antibodies for isolation of highly pure plasma membranes.

In plasma membrane proteome research, contamination of the isolated plasma membrane fraction with proteins from other organelles is still a problem. Even if highly specific isolation methods are used, such as density gradient centrifugation combined with selective extraction, contaminating proteins cannot be completely removed. To solve this problem, a protocol for the isolation of highly pure plasma membrane fractions from rat liver and two different hepatocellular carcinoma cell lines was developed. Magnetic beads with immobilized mAb's against highly expressed membrane proteins were used for specific binding of membrane vesicles and their separation from other organelles. Isolated plasma membranes were further selectively solubilized with different reagents and analyzed by use of different methods, such as Western blotting, 1- and 2-DE, and MS. Purification and further selective solubilization was validated by use of mAb's against the marker integral plasma membrane protein carcinoembryonic antigen cell adhesion molecule 1, and identification of isolated proteins by MS. The method presented here minimizes contamination with other organelles and enables further identification of membrane proteins.

Animals↗

PubMed2006

Aligned carbon nanotube-polymer hybrid architectures for diverse flexible electronic applications.

We present the fabrication and electrical characterization of a flexible hybrid composite structure using aligned multiwall carbon nanotube arrays in a poly(dimethylsiloxane) (PDMS) matrix. Using lithographically patterned nanotube arrays, one can make these structures at any length scale from submicrometer levels to bulk quantities. The PDMS matrix undergoes excellent conformal filling within the dense nanotube network, giving rise to extremely flexible conducting structures with unique electromechanical properties. We demonstrate its robustness against high stress conditions, under which the composite is found to retain its conducting nature. We also demonstrate that these structures can be utilized directly as flexible field-emission devices. Our devices show some of the best field-enhancement factors and turn-on electric fields reported so far.

Journal Article↗

PubMed2006

Mental representation of verb meaning: behavioral and electrophysiological evidence.

Previous psycholinguistic research has debated the nature of the mental representation of verbs and the access of relevant verb information in sentence processing. In this study, we used behavioral and electrophysiological methods to examine the representation of verbs in and out of sentence contexts. In five experiments, word naming and event-related potential (ERP) components were used to measure the speed and the amplitude, respectively, associated with different verb-object combinations that result in different degrees of fit between the verb and its object. Both naming speed and ERP amplitudes (N400) are proven to be sensitive indices of the degree of fit, varying as a function of how well the object fits the verb in terms of selectional restrictions. The results suggest that the semantic features of the verb's arguments are an integral part of the mental representation of verbs, and such information of the verb is accessed and used on-line during sentence processing. Implications of these results are discussed in light of recent computational semantic models that view the lexicon through high-order lexical co-occurrences in language use.

Adolescent↗

PubMed2005

Multifunctional brushes made from carbon nanotubes.

Brushes are common tools for use in industry and our daily life, performing a variety of tasks such as cleaning, scraping, applying and electrical contacts. Typical materials for constructing brush bristles include animal hairs, synthetic polymer fibres and metal wires (see, for example, ref. 1). The performance of these bristles has been limited by the oxidation and degradation of metal wires, poor strength of natural hairs, and low thermal stability of synthetic fibres. Carbon nanotubes, having a typical one-dimensional nanostructure, have excellent mechanical properties, such as high modulus and strength, high elasticity and resilience, thermal conductivity and large surface area (50-200 m2 g(-1)). Here we construct multifunctional, conductive brushes with carbon nanotube bristles grafted on fibre handles, and demonstrate their several unique tasks such as cleaning of nanoparticles from narrow spaces, coating of the inside of holes, selective chemical adsorption, and as movable electromechanical brush contacts and switches. The nanotube bristles can also be chemically functionalized for selective removal of heavy metal ions.

Crystallization↗

PubMed2005

Bottom-up growth of carbon nanotube multilayers: unprecedented growth.

An unusual growth phenomenon, with no precedent in vapor-phase thin film growth, is described here, for the case of the growth of stacked multiple layers of vertically aligned carbon nanotubes(1-6) on solid substrates. As multiple layers of ordered nanotubes are sequentially deposited from the vapor onto the substrate, each layer nucleates and grows from the original substrate surface at the bottom of the existing multiple stacks of nanotubes. In contrast to conventional understanding of thin film deposition,(7) the mechanism here has similarities to porous oxide film formation on surfaces.(8) The stacked layers of aligned nanotubes act as fully permeable membranes for the downward diffusion of growth precursor vapors, allowing growth to occur at the buried solid interface. The preexisting multiple nanotube stacks lift up to accommodate the vertical growth of fresh layers, allowing the formation of nanotube towers extending in millimeter lengths. Our results provide evidence for a new growth phenomenon, characterized by selective, interface-driven, bottom-up growth of self-assembled nanowires at buried interfaces, covered with weakly adhering thick porous membranes.

Journal Article↗