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Featured researches published by Meifang Jin.


Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology | 2008

A comparative study on the phylogenetic diversity of culturable actinobacteria isolated from five marine sponge species

Haitao Zhang; Wei Zhang; Yan Jin; Meifang Jin; Xingju Yu

A cultivation-based approach was employed to compare the culturable actinobacterial diversity associated with five marine sponge species (Craniella australiensis, Halichondria rugosa, Reniochalina sp., Sponge sp., and Stelletta tenuis). The phylogenetic affiliation of the actinobacterial isolates was assessed by 16S rDNA-RFLP analysis. A total of 181 actinobacterial strains were isolated using five different culture media (denoted as M1–M5). The type of medium exhibited significant effects on the number of actinobacteria recovered, with the highest number of isolates on M3 (63 isolates) and the lowest on M1 (12 isolates). The genera isolated were also different, with the recovery of three genera on M2 and M3, and only a single genus on M1. The number of actinobacteria isolated from the five sponge species was significantly different, with a count of 83, 36, 30, 17, and 15 isolates from S. tenuis, H. rugosa, Sponge sp., Reniochalina sp., and C. australiensis, respectively. M3 was the best isolation medium for recovery of actinobacteria from S. tenuis, H. rugosa, and Sponge sp., while no specific medium preference was observed for the recovery of actinobacteria from Reniochalina sp., and C. australiensis. The RFLP fingerprinting of 16S rDNA genes digested with HhaI revealed six different patterns, in which 16 representative 16S rDNAs were fully sequenced. Phylogenetic analysis indicated that 12 strains belong to the group Streptomyces, three strains belong to Pseudonocardia, and one strain belongs to Nocardia. Two strains C14 (from C. australiensis) and N13 (from Sponge sp.) have only 96.26% and 96.27% similarity to earlier published sequences, and are therefore potential candidates for new species. The highest diversity of three actinobacteria genera was obtained from Sponge sp., though the number of isolates was low. Two genera of actinobacteria, Streptomyces, and Pseudonocardia, were isolated from both S. tenuis and C. australiensis. Only the genus of Streptomyces was isolated from H. rugosa and Reniochalina sp. Sponge species have been demonstrated here to vary as sources of culturable actinobacterial diversity, and the methods for sampling such diversity presented may be useful for improved sampling of such diversity.


Journal of Biotechnology | 2003

Optimizing the formation of in vitro sponge primmorphs from the Chinese sponge Stylotella agminata (Ridley).

Wei Zhang; Xiaoying Zhang; Xupeng Cao; Junyi Xu; Quanyu Zhao; Xingju Yu; Meifang Jin; Maicun Deng

The establishment and optimization of in vitro primmorph formation from a Chinese sponge, Stylotella agminata (Ridley), collected from the South China Sea, were investigated. Our aims were to identify the key factors affecting primmorph formation in this species and to optimize the technique for developing an in vitro primmorph culture system. The size of dissociated cells from S. agminata is relatively small, in the range between 5 and 10 microm. Round-shaped primmorphs of less than 100 microm were formed 3 days after transferring the dissociated cells into seawater containing Ca(2+) and Mg(2+). The effect of various cell dissociation conditions, inoculum cell density, concentration of antibiotics, pH, and temperature was further investigated upon the formation of primmorphs. The time required for primmorph formation, primmorph size distribution, and the proliferating capability were microscopically documented. Healthy sponge S. agminata, inoculum cell density and culture temperature play a critical role for the successful formation of primmorphs and that the microbial contamination will have to be controlled.


Biotechnology Progress | 2006

Role of Carbonyl Cyanide m‐Chlorophenylhydrazone in Enhancing Photobiological Hydrogen Production by Marine Green Alga Platymonas subcordiformis

Chunqiu Ran; Xingju Yu; Meifang Jin; Wei Zhang

We demonstrated that a significant volume of H2 gas could be photobiologically produced by a marine green alga Platymonas subcordiformis when an uncoupler of photophosphorylation, carbonyl cyanide m‐chlorophenylhydrazone (CCCP), was added after 32 h of anaerobic dark incubation, whereas a negligible volume of H2 gas was produced without CCCP. The role of CCCP in enhancing photobiological H2 production was delineated. CCCP as an ADRY agent (agent accelerating the deactivation reactions of water‐splitting enzyme system Y) rapidly inhibited the photosystem II (PSII) activity of P. subcordiformis cells, resulting in a markedly decline in the coupled oxygen evolution. The mitochondrial oxidative respiration was only slightly inactivated by CCCP, which depleted O2 in the light. As a result, anaerobiosis during the stage of photobiological H2 evolution was established, preventing severe O2 inactivation of the reversible hydrogenase in P. subcordiformis. The uncoupling effect of CCCP accelerates electron transfer from water due to a disruption of the proton motive force and release of ΔpH across the thylakoid membrane and thus enhances the accessibility of electron and H+ to hydrogenase. The electrons for hydrogen photoevolution are mainly from the photolysis of water (90%). Upon the addition of CCCP, Chl a/b ratio increased, which implies a decrease in the light‐harvesting PSII antennae or an increase in PSII/PSI ratio, possibly resulting in higher efficiency of utilization of light energy. The enhancement of H2 evolution by the addition of CCCP is mostly due to the combination of the above three mechanisms. However, the disruption of the proton gradient across the thylakoid membrane may prevent a sustained photobiological H2 evolution due to a shortfall of ATP generation essential for the maintenance and repair functions of the cells.


Biomolecular Engineering | 2003

Biopotentials of marine sponges from China oceans: past and future

Wei Zhang; Song Xue; Quanyu Zhao; Xiaoying Zhang; Jinhe Li; Meifang Jin; Xinju Yu; Quan Yuan

An extensive literature survey of over 17 Journals was carried out on Chinese sponges and their natural products in the period from 1980 to 2001. This review is thus intended to provide the first thorough overview of research on marine sponges from China Ocean territories. Information is provided about the rather-limited taxonomic study of Chinese marine sponges, with an analysis on their distribution and diversity. Research findings on the natural products and their bioactivity screening from Chinese sponges are summarized. The weaknesses, gaps and problems in the past R&D program of Chinese sponges are identified, which point to the future opportunities in exploiting these huge untapped sponge resources. The report is expected to serve as an entry point for understanding Chinese sponges and for furthering R&D on their bioactive compounds for new drug development.


Biotechnology Progress | 2008

Formulation of a basal medium for primary cell culture of the marine sponge Hymeniacidon perleve.

Quanyu Zhao; Wei Zhang; Meifang Jin; Xingju Yu; Maicun Deng

Marine sponge cell culture is a potential route for the sustainable production of sponge‐derived bioproducts. Development of a basal culture medium is a prerequisite for the attachment, spreading, and growth of sponge cells in vitro. With the limited knowledge available on nutrient requirements for sponge cells, a series of statistical experimental designs has been employed to screen and optimize the critical nutrient components including inorganic salts (ferric ion, zinc ion, silicate, and NaCl), amino acids (glycine, glutamine, and aspartic acid), sugars (glucose, sorbitol, and sodium pyruvate), vitamin C, and mammalian cell medium (DMEM and RPMI 1640) using MTT assay in 96‐well plates. The marine sponge Hymeniacidon perleve was used as a model system. Plackett‐Burman design was used for the initial screening, which identified the significant factors of ferric ion, NaCl, and vitamin C. These three factors were selected for further optimization by Uniform Design and Response Surface Methodology (RSM), respectively. A basal medium was finally established, which supported an over 100% increase in viability of sponge cells.


Biotechnology and Bioprocess Engineering | 2005

Instability of Anthocyanin Accumulation in Vitis vinifera L. var. Gamay Freaux Suspension Cultures

Qu Jg; Wei Zhang; Xingju Yu; Meifang Jin

The inherent instability of metabolite production in plant cell culture-based bioprocessing is a major problem hindering its commercialization. To understand the extent and causes of this instability, this study was aimed at understanding the variability of anthocyanin accumulation during long-term subcultures, as well as within subculture batches, inVitis vinifera cell cultures. Therefore, four cell line suspensions ofVitis vinifera L. var. Gamay Fréaux, A, B, C and D, originated from the same callus by cell-aggregate cloning, were established with starting anthocyanin contents of 2.73±0.15, 1.45±0.04, 0.77±0.024 and 0.27±0.04 CV (Color Value)/g-FCW (fresh cell weight), respectively. During weekly subculturing of 33 batches over 8 months, the anthocyanin biosynthetic capacity was gradually lost at various rates, for all four cell lines, regardless of the significant difference in the starting anthocyanin content. Contrary to this general trend, a significant fluctuation in the anthocyanin content was observed, but with an irregular cyclic pattern. The variabilities in the anthocyanin content between the subcultures for the 33 batches, as represented by the variation coefficient (VC), were 58, 57, 54, and 84% forV. vinifera cell lines A, B, C and D, respectively. Within one subculture, the VCs from 12 replicate flasks for each of 12 independent subcultures were averaged, and found to be 9.7%, ranging from 4 to 17%. High- and low-producing cell lines, VV05 and VV06, with 1.8-fold differences in their basal anthocyanin contents, exhibited different inducibilities tol-phenylalanine feeding, methyl jasmonate and light irradiation. The low-producing cell line showed greater potential in enhanced the anthocyanin production.


Chinese Journal of Biotechnology | 2006

Effect of homogeneity on cell growth and anthocyanin biosynthesis in suspension cultures of Vitis vinifera

Qu Jg; Wei Zhang; Meifang Jin; Xue Yu

The instability of secondary metabolite production is a ubiquitous problem in plant cell culture. To understand the instability, the investigation of anthocyanin accumulation in suspension cultures of Vitis vinifera, as a model system, has been initiated in our laboratory. Suspension culture of a relatively homogeneous cell line E of V. vinifera, was established by long-term cell line selection by anthocyanin content differentiation. The aggregate size of E was smaller than that of other cell lines obtained by routine screening method. The variation coefficients of anthocyanin content in suspension cultures of E were 8.7% in long-term subcultures and 5% in repeated flasks, respectively. The effects of elicitor, precursor feeding and light irridiation on biomass and anthocyanin accumulation in suspension cultures of E had been investigated and the results showed that all the variation coefficients were lower than 12% and this indicated the importance of homogeneity on stable production in plant cell culture. With the combination treatment of 30micromol/L phenylalanine and 218micromol/L methyl jasmonate in the dark in suspension cultures of E, the anthocyanin content and production in suspension culture of E was 5.89-fold and 4.30-fold of the controls, respectively, and all the variation coefficients of biomass and anthocyanin accumulation were lower than those of the controls in 5 successive subcultures.


Biotechnology Progress | 2003

Attachment of marine sponge cells of Hymeniacidon perleve on microcarriers

Quanyu Zhao; Meifang Jin; Werner E. G. Müller; Wei Zhang; Xingju Yu; Maicun Deng

Toward the development of an in vitro cultivation of marine sponge cells for sustainable production of bioactive metabolites, the attachment characteristics of marine sponge cells of Hymeniacidon perleve on three types of microcarriers, Hillex, Cytodex 3, and glass beads, were studied. Mixed cell population and enriched cell fractions of specific cell types by Ficoll gradient centrifugation (6%/8%/15%/20%) were also assessed. Cell attachment ratio (defined as the ratio of cells attached on microcarrier to the total number of cells in the culture) on glass beads is much higher than that on Cytodex 3 and Hillex for both mixed cell population and cell fraction at Ficoll 15–20% interface. The highest attachment ratio of 41% was obtained for the cell fraction at Ficoll 15–20% interface on glass beads, which was significantly higher than that of a mixed cell population (18%). The attachment kinetics on glass beads indicated that the attachment was completed within 1 h. Cell attachment ratio decreases with increase in cell‐to‐microcarrier ratio (3–30 cells/bead) and pH (7.6–9.0). The addition of serum and BSA (bovine serum albumin) reduced the cell attachment on glass beads.


Chinese Journal of Biotechnology | 2006

Impact of subculture cycles and inoculum sizes on suspension cultures of Vitis vinifera

Qu Jg; Wei Zhang; Hu Ql; Meifang Jin

The commercial application of plant cell cultures is often hindered by the instability of secondary metabolite biosynthesis, where the metabolite yield fluctuates and decline dramatically over subcultures. This study proposed that such instability is due to the fluctuations of culture variables. To validate this hypothesis, the effects of the fluctuations of two culture variables (subculture cycle and inoculum size) on the biomass, anthocyanin biosynthesig, intracellular carbon, nitrogen and phosphate during continuous 10 subculture cycles were investigated. The subculture cycle was fluctuated for 12h in a 7 day cycle (6.5, 7 and 7.5 d), and the inoculum size was fluctuated by 20% on basis of 2.00 g (1.60, 2.00 and 2.40 g). It was found that all the measured culture parameters fluctuated over the 10 subculture cycles. The fluctuation in terms of inoculum sizes had a greater effect on the stability of anthocyanin biosynthesis in suspension cultures of V. vinifera. Among all the subculture conditions investigated, 7d-subculture cycle and 1.60 g-inoculum size was the best one to hold the relatively stable anthocyanin production. The anthocyanin yield presented a negative correlation with intracellular sucrose content or intracellular total phosphate content.


Chinese Journal of Biotechnology | 2007

[Subcellular localization and identification of hydrogenase isolated from the marine green alga Platymonas subcordiformis using immunoprecipitation and MALDI-TOF MS].

Zhen Guo; Zhaoan Chen; Xingju Yu; Meifang Jin; Li W; Wei Zhang

A marine unicellular green alga, Platymonas subcordiformis, was demonstrated to photobiologically produce hydrogen gas from seawater. The objective of this study was to localize and identify the hydrogenase isolated from P. subcordiformis. Adaptation in the presence of inhibitors of protein biosynthesis indicated that the hydrogenase was much more inhibited by cycloheximide than that by chloramphenicol. The result suggested that the hydrogenase isolated from P. subcordiformis is probably synthesized in cytoplasmic ribosomes. Both Western blot analysis and immunogold electron microscopy demonstrate that the P. subcordiformis hydrogenase is mainly located in the chloroplast stroma. The proteins that reacted specifically with the antibodies against the iron hydrogenase isolated from Chlamydomonas reinhardtii were concentrated by immunoprecipitation. The separated protein bands were cut out of the SDS-PAGE gel, in-gel digested by trypsin, and analyzed by Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). Mascot was employed for analysis of the MALDI data using the public databases NCBInr. The hydrogenase isolated from P. subcordiformis was identified to be the Fe-hydrogenase.

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Xingju Yu

Dalian Institute of Chemical Physics

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Zhaoan Chen

Dalian Institute of Chemical Physics

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Quanyu Zhao

Kyushu Institute of Technology

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Chunqiu Ran

Dalian Institute of Chemical Physics

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Qu Jg

Dalian Institute of Chemical Physics

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Xupeng Cao

Dalian Institute of Chemical Physics

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Yan Jin

Dalian Institute of Chemical Physics

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Zhen Guo

Dalian Institute of Chemical Physics

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