Publications by authors named "Zebin Liu"

9 Publications

  • Page 1 of 1

Overexpression and biochemical characterization of a truncated endo-α (1 → 3)-fucoidanase from alteromonas sp. SN-1009.

Food Chem 2021 Mar 7;353:129460. Epub 2021 Mar 7.

National Key Laboratory of Biochemical Engineering, National Engineering Research Center for Biotechnology (Beijing), Key Laboratory of Biopharmaceutical Production & Formulation Engineering, PLA, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China. Electronic address:

Endo-fucoidanases are important in structural analysis of fucoidans and preparation of fuco-oligosaccharides. However their enzymological properties and analysis of degradation products are scarcely investigated. Truncated endo-α (1 → 3)-fucoidanase Fda1 (tFda1B from Alteromonas sp. was overexpressed and characterized, showing highest activity at pH 7.0, 35 °C, and 1.0 M NaCl. Its K and k were 3.88 ± 0.81 mg/mL and 0.82 ± 0.17 min. Fe and Mn enhanced activity by 100% and 19.5% respectively. Co and Cu completely inactivated tFda1B, whereas Ni, Mg, Zn, Pb, Ca, Ba and Li decreased activity by 58.8%, 56.0%, 50.6%, 47.7%, 28.9%, 15.6% and 37.5%, respectively. Catalytic residues were identified through structure and sequence alignment, and confirmed by mutagenesis. Degradation products of Kjellmaniella crassifolia fucoidan by tFda1B were characterized by LC-ESI-MS/MS, confirming tFda1B belongs to endo-(1 → 3)-fucoidanases, and backbone of K. crassifolia fucoidan is 1 → 3 fucoside linkage. This endo-α (1 → 3)-fucoidanase would be useful for elucidating fucoidan structures, and be used as a food enzyme.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodchem.2021.129460DOI Listing
March 2021

GASC1 promotes glioma progression by enhancing NOTCH1 signaling.

Mol Med Rep 2021 May 2;23(5). Epub 2021 Mar 2.

Department of Neurosurgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China.

Recent studies have reported that gene amplified in squamous cell carcinoma 1 (GASC1) is involved in the progression of several types of cancer. However, whether GASC1 promotes glioma progression remains unknown. Therefore, the present study aimed to investigate the effect of GASC1 exposure on glioma tumorigenesis. The western blot demonstrated that grade III and IV glioma tissues exhibited a higher mRNA and protein expression of GASC1. Moreover, CD133+ U87 or U251 cells from magnetic cell separation exhibited a higher GASC1 expression. Invasion Transwell assay, clonogenic assay and wound healing assay have shown that GASC1 inhibition using a pharmacological inhibitor and specific short hairpin (sh)RNA suppressed the invasive, migratory and tumorsphere forming abilities of primary culture human glioma cells. Furthermore, GASC1‑knockdown decreased notch receptor (Notch) responsive protein hes family bHLH transcription factor 1 (Hes1) signaling. GASC1 inhibition reduced notch receptor 1 (NOTCH1) expression, and a NOTCH1 inhibitor enhanced the effects of GASC1 inhibition on the CD133+ U87 or U251 cell tumorsphere forming ability, while NOTCH1 overexpression abrogated these effects. In addition, the GASC1 inhibitor caffeic acid and/or the NOTCH1 inhibitor DAPT (a γ‑Secretase Inhibitor), efficiently suppressed the human glioma xenograft tumors. Thus, the present results demonstrated the importance of GASC1 in the progression of glioma and identified that GASC1 promotes glioma progression, at least in part, by enhancing NOTCH signaling, suggesting that GASC1/NOTCH1 signaling may be a potential therapeutic target for glioma treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3892/mmr.2021.11949DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7974312PMC
May 2021

Estrogen receptor α/prolactin receptor bilateral crosstalk promotes bromocriptine resistance in prolactinomas.

Int J Med Sci 2020 23;17(18):3174-3189. Epub 2020 Oct 23.

Department of Neurosurgery, Zhongnan hospital of Wuhan university, Wuhan, Hubei 430071, P.R. China.

Prolactinomas are the most common type of functional pituitary adenoma. Although bromocriptine is the preferred first line treatment for prolactinoma, resistance frequently occurs, posing a prominent clinical challenge. Both the prolactin receptor (PRLR) and estrogen receptor α (ERα) serve critical roles in the development and progression of prolactinomas, and whether this interaction between PRLR and ERα contributes to bromocriptine resistance remains to be clarified. In the present study, increased levels of ERα and PRLR protein expression were detected in bromocriptine-resistant prolactinomas and MMQ cells. Prolactin (PRL) and estradiol (E2) were found to exert synergistic effects on prolactinoma cell proliferation. Furthermore, PRL induced the phosphorylation of ERα via the JAK2-PI3K/Akt-MEK/ERK pathway, while estrogen promoted PRLR upregulation via pERα. ERα inhibition abolished E2-induced PRLR upregulation and PRL-induced ERα phosphorylation, and fulvestrant, an ERα inhibitor, restored pituitary adenoma cell sensitivity to bromocriptine by activating JNK-MEK/ERK-p38 MAPK signaling and cyclin D1 downregulation. Collectively, these data suggest that the interaction between the estrogen/ERα and PRL/PRLR pathways may contribute to bromocriptine resistance, and therefore, that combination treatment with fulvestrant and bromocriptine (as opposed to either drug alone) may exert potent antitumor effects on bromocriptine-resistant prolactinomas.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7150/ijms.51176DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7646122PMC
October 2020

Pimozide augments bromocriptine lethality in prolactinoma cells and in a xenograft model via the STAT5/cyclin D1 and STAT5/Bcl‑xL signaling pathways.

Int J Mol Med 2021 Jan 5;47(1):113-124. Epub 2020 Nov 5.

Department of Neurosurgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei 430071, P.R. China.

As hyperprolactinemia is observed in patients with bromocriptine‑resistant prolactinoma, prolactin (PRL) has been implicated in the development of bromocriptine resistance. Since PRL primarily mediates cell survival and drug resistance via the Janus kinase‑2 (JAK2)/signal transducer and activator of transcription 5A (STAT5) signaling pathway, the STAT5 inhibitor, pimozide, may inhibit cell proliferation and reverse bromocriptine resistance in prolactinoma cells. In the present study, compared with bromocriptine or pimozide alone, the combination of pimozide and bromocriptine exerted enhanced reduction in cell growth and proliferation, and increased apoptosis and cell cycle arrest in bromocriptine‑resistant prolactinoma cells. A reduction in phospho‑STAT5, cyclin D1 and B‑cell lymphoma extra‑large (Bcl‑xL) expression levels were observed in cells treated with the combination of drugs. In addition, pimozide suppressed spheroid formation of human pituitary adenoma stem‑like cells, and reduced the protein expression of the cancer stem cell markers, CD133 and nestin. Pimozide did not exert any additional antitumor activity in STAT5‑knockdown primary culture cells of human bromocriptine‑resistant prolactinomas. Furthermore, Pimozide combined with bromocriptine treatment significantly reduced human prolactinoma xenograft growth. Western blot and immunohistochemical analyses also demonstrated significant inhibition of cell proliferation and stem cell marker proteins in vivo. Collectively, these data indicated that pimozide treatment reduced prolactinoma growth by targeting both proliferating cells and stem cells, at least in part, by inhibiting the STAT5/Bcl‑xL and STAT5/cyclin D1 signaling pathways.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3892/ijmm.2020.4784DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7723514PMC
January 2021

Water yield variation with elevation, tree age and density of larch plantation in the Liupan Mountains of the Loess Plateau and its forest management implications.

Sci Total Environ 2021 Jan 19;752:141752. Epub 2020 Aug 19.

Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Key Laboratory of Forest Ecology of National Forestry and Grassland Administration, Beijing 100091, China.

Large scale afforestation mainly for erosion control or timber production and a very strict logging ban policy in recent decades led to many over-dense stands and remarkable water yield reduction in the dryland region of the Loess Plateau in northwest China. To guide the integrated forest-water management at stand level, a study on the response of water yield from larch (Larix principis-rupprechtii) plantations to key stand structure and site factors was carried out in the Liupan Mountains. Models of leaf area index (LAI) of forest canopy and stand evapotranspiration (ET) in the growing season were developed and fitted. The growing season water yield was calculated based on water budget. The results showed that: (1) The LAI increases with rising tree density firstly quickly and then slowly and finally tending to its maximum; but firstly increases and then decreases with rising tree age and elevation. The LAI model coupling the effects of tree density, age, and elevation works well. (2) The ET model reflecting the coupled effects of precipitation, potential evapotranspiration, LAI and soil moisture can well predict the ET variation. (3) The water yield decreases gradually with rising tree density, but firstly decreases and then increases with rising tree age and elevation. The lowest water yield appears at the age of 30 years and at an elevation of 2420 m. (4) The implications of this study for integrated forest-water management are: defining water yield as the dominant forest service at high or low elevations, but quality timber production as the dominant service at medium elevations; arranging rational thinning for dense forests around the age of 30 years; designing a mosaic distribution of forest ages within watersheds. Applying the study outcomes can promote the integration of water yield management with traditional forest management to ensure the sustainability of water supply in dryland regions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2020.141752DOI Listing
January 2021

Overexpression and Biochemical Characterization of an Endo-α-1,4-polygalacturonase from in .

Int J Mol Sci 2020 Mar 19;21(6). Epub 2020 Mar 19.

National Key Laboratory of Biochemical Engineering, National Engineering Research Center for Biotechnology (Beijing), Key Laboratory of Biopharmaceutical Production & Formulation Engineering, PLA, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China.

Pectinases have many applications in the industry of food, paper, and textiles, therefore finding novel polygalacturonases is required. Multiple sequence alignment and phylogenetic analysis of AnEPG (an endo-α-1,4-polygalacturonase from ) and other GH 28 endo-polygalacturonases suggested that AnEPG is different from others. AnEPG overexpressed in was characterized. AnEPG showed the highest activity at pH 4.0, and exhibited moderate activity over a narrow pH range (pH 2.0-5.0) and superior stability in a wide pH range (pH 2.0-12.0). It displayed the highest activity at 60 °C, and retained >42.2% of maximum activity between 20 and 80 °C. It was stable below 40 °C and lost activity very quickly above 50 °C. Its apparent kinetic parameters against PGA (polygalacturonic acid) were determined, with the and values of 8.3 mg/mL and 5640 μmol/min/mg, respectively. Ba and Ni enhanced activity by 12.2% and 9.4%, respectively, while Ca, Cu, and Mn inhibited activity by 14.8%, 12.8%, and 10.2% separately. Analysis of hydrolysis products by AnEPG proved that AnEPG belongs to an endo-polygalacturonase. Modelled structure of AnEPG by I-TASSER showed structural characteristics of endo-polygalacturonases. This pectinase has great potential to be used in food industry and as feed additives.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21062100DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7139513PMC
March 2020

SmpB down-regulates proton-motive force for the persister tolerance to aminoglycosides in Aeromonas veronii.

Biochem Biophys Res Commun 2018 12 16;507(1-4):407-413. Epub 2018 Nov 16.

Hainan Key Laboratory for Sustainable Utilization of Tropical Bioresources, Institute of Tropical Agriculture and Forestry, Hainan University, 570228, Haikou, China. Electronic address:

Bacterial persisters comprise a small fraction of phenotypically heterogeneous variants with transient capability for survival when exposed to high concentrations of antibiotic. In aquatic pathogenic bacteria Aeromonas veronii, Small Protein B (SmpB), the core factor of trans-translation system, was identified as a new persistence-related gene. The SmpB deletion exhibited a higher susceptibility and lower persister cell formation under aminoglycosides antibiotics pressure compared with wild type. The transcriptional and translational activities of smpB gene were significantly enhanced by the gentamicin challenge in exponential phase, but not changed in stationary phase. The transcriptomic analysis revealed that the smpB deletion stimulated the production of proton-motive force (PMF). The cell survival induced by carbonyl cyanide m-chlorophenyl hydrazone (CCCP) further verified that SmpB variation affected the quantities of PMF. Taken together, these results uncovered a novel mechanism of persister formation mediated by SmpB under aminoglycosides treatments.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbrc.2018.11.052DOI Listing
December 2018

Simultaneous determination of acetaminophen and dihydrocodeine in human plasma by UPLC-MS/MS: Its pharmacokinetic application.

J Chromatogr B Analyt Technol Biomed Life Sci 2015 Jun 27;992:91-5. Epub 2015 Apr 27.

The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, PR China. Electronic address:

An ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine acetaminophen (AAP) and dihydrocodeine (DHC) in human plasma simultaneously. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard midazolam were separated on an Acquity UPLC BEH C18 column and mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 151.2→110.0 and m/z 302.3→199.2 were used to quantify for AAP and DHC, respectively. The linearity of this method was found to be within the concentration range of 50-10000ng/mL for AAP, and 1-100ng/mL for DHC in human plasma, respectively. The lower limit of quantification (LLOQ) was 50ng/mL and 1ng/mL for AAP and DHC in human plasma, respectively. The relative standard deviations (RSD) of intra and inter precision were less than 10% for both AAP and DHC. The analysis time of per sample was 1.0min. The developed and validated method was successfully applied to a pharmacokinetic study of AAP (500mg) with DHC (20mg) capsule in Chinese healthy volunteers (N=20).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jchromb.2015.04.031DOI Listing
June 2015

Effect of off-season flooding on growth, photosynthesis, carbohydrate partitioning, and nutrient uptake in Distylium chinense.

PLoS One 2014 15;9(9):e107636. Epub 2014 Sep 15.

State Forestry Administration Key Laboratory of Forest Ecology and Environment, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, PR China.

Distylium chinense is an evergreen shrub used for the vegetation recovery of floodplain and riparian areas in Three Gorges Reservoir Region. To clarify the morphological and physiological responses and tolerance of Distylium chinense to off-season flooding, a simulation flooding experiment was conducted during autumn and winter. Results indicated that the survival rate of seedlings was 100%, and that plant height and stem diameter were not significantly affected by flooding. Adventitious roots and hypertrophic lenticels were observed in flooded seedlings after 30 days of flooding. Flooding significantly reduced the plant biomass of roots, net photosynthetic rate (Pn), stomatal conductance (gs), transpiration rate (Tr), maximum photochemical efficiency (Fv/Fm), photochemical quenching (qP), and electron transport rate (ETR) in leaves, and also affected the allocation and transport of carbohydrate and nutrients. However, D. chinense was able to maintain stable levels of Pn, Fv/Fm, qP, ETR, and nutrient content (N and P) in leaves and to store a certain amount of carbohydrate in roots over prolonged durations of flooding. Based on these results, we conclude that there is a high flooding tolerance in D. chinense, and the high survival rate of D. chinense may be attributable to a combination of morphological and physiological responses to flooding.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0107636PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4164644PMC
December 2015