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result(s) for
"Bo-Xue Tian"
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Computational-guided discovery and characterization of a sesquiterpene synthase from Streptomyces clavuligerus
by
Bo-Xue Tian
,
Gurusankar Ramamoorthy
,
Ronald D. Seidel
in
active sites
,
Algorithms
,
Alkyl and Aryl Transferases - chemistry
2015
Significance This paper describes a novel strategy for predicting the function of terpene synthases. Functional assignment of terpene synthases is a daunting task because product selectivity is not high in many terpene synthases, and mutations in and near the active sites of selective enzyme can result in synthesis of different products. Using a homology model of an unknown terpene synthase, we developed an algorithm that predicted the enzyme synthesizes a linear triquinane. We confirmed this prediction; specifically, the enzyme converts farnesyl diphosphate to a linear triquinine sesquiterpene: (5 S ,7 S ,10 R ,11 S )-cucumene. The findings highlight the potential for using computational approaches to assist in the discovery and characterization of unknown terpene synthases.
Terpenoids are a large structurally diverse group of natural products with an array of functions in their hosts. The large amount of genomic information from recent sequencing efforts provides opportunities and challenges for the functional assignment of terpene synthases that construct the carbon skeletons of these compounds. Inferring function from the sequence and/or structure of these enzymes is not trivial because of the large number of possible reaction channels and products. We tackle this problem by developing an algorithm to enumerate possible carbocations derived from the farnesyl cation, the first reactive intermediate of the substrate, and evaluating their steric and electrostatic compatibility with the active site. The homology model of a putative pentalenene synthase (Uniprot: B5GLM7) from Streptomyces clavuligerus was used in an automated computational workflow for product prediction. Surprisingly, the workflow predicted a linear triquinane scaffold as the top product skeleton for B5GLM7. Biochemical characterization of B5GLM7 reveals the major product as (5 S ,7 S ,10 R ,11 S )-cucumene, a sesquiterpene with a linear triquinane scaffold. To our knowledge, this is the first documentation of a terpene synthase involved in the synthesis of a linear triquinane. The success of our prediction for B5GLM7 suggests that this approach can be used to facilitate the functional assignment of novel terpene synthases.
Journal Article
Predicting the Functions and Specificity of Triterpenoid Synthases: A Mechanism-Based Multi-intermediate Docking Approach
by
Wallrapp, Frank H.
,
Chow, Jeng-Yeong
,
Poulter, C. Dale
in
Alkyl and Aryl Transferases - chemistry
,
Alkyl and Aryl Transferases - metabolism
,
Analysis
2014
Terpenoid synthases construct the carbon skeletons of tens of thousands of natural products. To predict functions and specificity of triterpenoid synthases, a mechanism-based, multi-intermediate docking approach is proposed. In addition to enzyme function prediction, other potential applications of the current approach, such as enzyme mechanistic studies and enzyme redesign by mutagenesis, are discussed.
Journal Article
Computational-guided discovery and characterization of a sesquiterpene synthase fromStreptomyces clavuligerus
Terpenoids are a large structurally diverse group of natural products with an array of functions in their hosts. The large amount of genomic information from recent sequencing efforts provides opportunities and challenges for the functional assignment of terpene synthases that construct the carbon skeletons of these compounds. Inferring function from the sequence and/or structure of these enzymes is not trivial because of the large number of possible reaction channels and products. We tackle this problem by developing an algorithm to enumerate possible carbocations derived from the farnesyl cation, the first reactive intermediate of the substrate, and evaluating their steric and electrostatic compatibility with the active site. The homology model of a putative pentalenene synthase (Uniprot: B5GLM7) fromStreptomyces clavuligeruswas used in an automated computational workflow for product prediction. Surprisingly, the workflow predicted a linear triquinane scaffold as the top product skeleton for B5GLM7. Biochemical characterization of B5GLM7 reveals the major product as (5S,7S,10R,11S)-cucumene, a sesquiterpene with a linear triquinane scaffold. To our knowledge, this is the first documentation of a terpene synthase involved in the synthesis of a linear triquinane. The success of our prediction for B5GLM7 suggests that this approach can be used to facilitate the functional assignment of novel terpene synthases.
Journal Article
Predicting the Functions and Specificity of Triterpenoid Synthases: A Mechanism-Based Multi-intermediate Docking Approach
by
Jacobson, Matthew P
,
Wallrapp, Frank H
,
Poulter, C Dale
in
Bioinformatics
,
Biosynthesis
,
Carbon
2014
Terpenoid synthases construct the carbon skeletons of tens of thousands of natural products. To predict functions and specificity of triterpenoid synthases, a mechanism-based, multi-intermediate docking approach is proposed. In addition to enzyme function prediction, other potential applications of the current approach, such as enzyme mechanistic studies and enzyme redesign by mutagenesis, are discussed.
Journal Article
Effects of Calcium Sulfate Combined with Platelet-rich Plasma on Restoration of Long Bone Defect in Rabbits
by
Hua Chen Xin-Ran Ji Qun Zhang Xue-Zhong Tian Bo-Xun Zhang Pei-Fu Tang
in
Animals
,
Blood platelets
,
Bone Regeneration - drug effects
2016
Background:The treatment for long bone defects has been a hot topic in the field of regenerative medicine.This study aimed to evaluate the therapeutic effects of calcium sulfate (CS) combined with platelet-rich plasma (PRP) on long bone defect restoration.Methods:A radial bone defect model was constructed through an osteotomy using New Zealand rabbits.The rabbits were randomly divided into four groups (n =10 in each group):a CS combined with PRP (CS-PRP) group,a CS group,a PRP group,and a positive (recombinant human bone morphogenetic protein-2) control group.PRP was prepared from autologous blood using a two-step centrifugation process.CS-PRP was obtained by mixing hemihydrate CS with PRP.Radiographs and histologic micrographs were generated.The percentage of bone regenerated bone area in each rabbit was calculated at 10 weeks.One-way analysis of variance was performed in this study.Results:The radiographs and histologic micrographs showed bone restoration in the CS-PRP and positive control groups,while nonunion was observed in the CS and PRP groups.The percentages of bone regenerated bone area in the CS-PRP (84.60 ± 2.87%) and positive control (52.21 ± 4.53%) groups were significantly greater than those in the CS group (12.34 ± 2.17%) and PRP group (16.52 ± 4.22%) (P 〈 0.001).In addition,the bone strength of CS-PRP group (43.l 0 ± 4.10%) was significantly greater than that of the CS group (20.10 ± 3.70%) or PRP group (25.10 ± 2.10%) (P 〈 0.001).Conclusion:CS-PRP functions as an effective treatment for long bone defects through stimulating bone regeneration and enhancing new bone strength.
Journal Article
Metal complexes of a novel bis-β-diketone-type ligand and its copper(II) complexes of two-photon biological imaging
2012
A curcumin derivative ligand, 1,7-bis(3-methoxyl-4-acetoxyl)phenyl-1,6-heptadiene-3,5-diketone (diacetylcurcumin, abbrevi- ated as HL), and its Cu and Ni complexes have been synthesized and fully characterized by elemental analyses, IR, 1HNMR and molar conductivity. The resulting complexes exhibit two-photon excited fluorescence (TPEF) in DMF, and have been proven to be potentially useful for two-photon microscopy imaging in living cells. In addition, cytotoxicity tests showed that the low-micromolar concentrations of ML2 did not cause significant reduction in cell viability over a period of at least 24 h and should be safe for further biological studies.
Journal Article
Towards a global One Health index: a potential assessment tool for One Health performance
by
Han, Le-Fei
,
Li, Min
,
Yin, Jing-Xian
in
Antimicrobial resistance
,
Capacity development
,
Cell-like framework
2022
Background
A One Health approach has been increasingly mainstreamed by the international community, as it provides for holistic thinking in recognizing the close links and inter-dependence of the health of humans, animals and the environment. However, the dearth of real-world evidence has hampered application of a One Health approach in shaping policies and practice. This study proposes the development of a potential evaluation tool for One Health performance, in order to contribute to the scientific measurement of One Health approach and the identification of gaps where One Health capacity building is most urgently needed.
Methods
We describe five steps towards a global One Health index (GOHI), including (i) framework formulation; (ii) indicator selection; (iii) database building; (iv) weight determination; and (v) GOHI scores calculation. A cell-like framework for GOHI is proposed, which comprises an external drivers index (EDI), an intrinsic drivers index (IDI) and a core drivers index (CDI). We construct the indicator scheme for GOHI based on this framework after multiple rounds of panel discussions with our expert advisory committee. A fuzzy analytical hierarchy process is adopted to determine the weights for each of the indicators.
Results
The weighted indicator scheme of GOHI comprises three first-level indicators, 13 second-level indicators, and 57 third-level indicators. According to the pilot analysis based on the data from more than 200 countries/territories the GOHI scores overall are far from ideal (the highest score of 65.0 out of a maximum score of 100), and we found considerable variations among different countries/territories (31.8–65.0). The results from the pilot analysis are consistent with the results from a literature review, which suggests that a GOHI as a potential tool for the assessment of One Health performance might be feasible.
Conclusions
GOHI—subject to rigorous validation—would represent the world’s first evaluation tool that constructs the conceptual framework from a holistic perspective of One Health. Future application of GOHI might promote a common understanding of a strong One Health approach and provide reference for promoting effective measures to strengthen One Health capacity building. With further adaptations under various scenarios, GOHI, along with its technical protocols and databases, will be updated regularly to address current technical limitations, and capture new knowledge.
Graphical Abstract
Journal Article
Polygonatum odoratum polysaccharide attenuates lipopolysaccharide‐induced lung injury in mice by regulating gut microbiota
2023
Polygonatum odoratum is appreciated for its edible and medicinal benefits especially for lung protection. However, the contained active components have been understudied, and further research is required to fully exploit its potential application. We aimed to probe into the beneficial effects of Polygonatum odoratum polysaccharide (POP) in lipopolysaccharide‐induced lung inflammatory injury mice. POP treatment could ameliorate the survival rate, pulmonary function, lung pathological lesions, and immune inflammatory response. POP treatment could repair intestinal barrier, and modulate the composition of gut microbiota, especially reducing the abundance of Klebsiella , which were closely associated with the therapeutic effects of POP. Investigation of the underlying anti‐inflammatory mechanism showed that POP suppressed the generation of pro‐inflammatory molecules in lung by inhibiting iNOS + M1 macrophages. Collectively, POP is a promising multi‐target microecological regulator to prevent and treat the immuno‐inflammation and lung injury by modulating gut microbiota.
Journal Article
Windblown dust in the Tarim basin, Northwest China
2025
Tarim Basin in western China is home to the world’s second-largest mobile dune desert, Taklimakan Desert, and it’s one of Asia’s primary sources of sand and dust storm. Observations of windblown dust are insufficient over this hyper-dry inland region. Here we present a comprehensive study based on consecutive in-situ field observations, meteorological records, environmental monitoring data and satellite measurements over the Tarim Basin for a full year in 2015. The results show that during the severe sand and dust storm events, the observed ambient PM
10
(particulate matter with an aerodynamic diameter ≤ 10 μm) concentration rises rapidly, with a maximum value exceeding 10,000 µg/m
3
per hour, while wind speeds reach 10–30 m/s and visibility is reduced to less than 10 m. Soil particulates can be blown vertically into the atmosphere at a height of 3–12 km. High volumes of dust deposition were measured at environmental monitoring stations, ranging from 1764 to 3800 g/m
2
yr. Those significant flux levels of ambient particulate matter (PM) concentrations and dust depositions are strongly associated with frequent dust occurrence in the arid environment of the Tarim Basin. Satellite measurements of aerosol optical depths (AOD) show a broad spatial pattern of dust aerosols distribution over the basin, with dense dust remaining suspended for long periods of time (3–5 months in spring and summer seasons). The wind regimes, basin-like topography, thermodynamic condition, and loose sandy surfaces greatly affect the regional aeolian dust environment in the Tarim Basin, which lead to a significantly high dust emission, ambient PM concentration and dust deposition.
Journal Article
Influence of gradient moisture content on hot pressing heat transfer of bamboo scrimber and it’s mathematical model
2024
Hot pressing process is an important process in the preparation of bamboo scrimber. However, due to the low thermal conductivity of fiberized bamboo veneer and the low heat transfer efficiency in the preparation of bamboo scrimber, the processing time is prolonged. At the same time, due to the influence of moisture content in the hot pressing process, the “boiler effect” of the core layer with a sharp increase in temperature and excessive steam pressure will appear, resulting in the risk of board explosion. In this study, a pavement method with gradient moisture content is explored, which can make the surface water vaporize and produce steam impact on the core layer, thus improving the heat transfer efficiency of the core layer and reducing the hot pressing period. The results show that when paving with gradient moisture content, the heating rate of the core layer is increased to a certain extent due to the promotion of steam impact on the core layer temperature. At the same time, due to the low moisture content of the core layer, the saturated steam cannot be formed from the moisture to the core layer, so the obvious “boiler effect” will not appear in the core layer, which can improve the hot pressing efficiency and reduce the risk of board explosion. In addition, this method does not reduce the mechanical properties of the panel. Meanwhile, this study introduces a straightforward gradient moisture content paving method and has made structural enhancements to the hot press machine, enabling the practical implementation of gradient moisture content paving.
Journal Article