Differentiation of Streptococcus thermophilus Strains in Commercial Direct Vat Set Yoghurt Starter

Chengjie Ma,Zhengjun Wu,Zhengjun Chen,Zhaoping Du,Kejie Sun,Aimin Ma 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.4

Based on inhibition of acid production, 100individual colonies of Streptococcus thermophilus isolated from commercial Direct Vat Set yoghurt starter DVS-M were typed into 2 groups of sensitive and insensitive to phage ϕ001, which was isolated from the lysis culture of the turbidity test. The ratio between the sensitive and insensitive isolates in DVS-M was calculated at 3:2. Whole-cell protein profile (WCPP) and randomly amplified polymorphic DNA (RAPD) analysis showed that both WCPP and RAPD patterns between sensitive and insensitive isolates were distinct, whereas isolates with the same sensitivity or insensitivity shared common WCPP and RAPD patterns. It suggested that all the sensitive isolates belong to one S. thermophilus strain and all the insensitive isolates belong to another one. This study revealed that DVS-M yoghurt starter consists of 2 S. thermophilus strains with different phage sensitivity.

Starter Culture Design to Overcome Phage Infection During Yogurt Fermentation

Chengjie Ma,Zhengjun Chen,Guangyu Gong,Lifen Huang,Sha Li,Aimin Ma 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.2

Streptococcus thermophilus phages present hazards for yogurt processing. In order to avoid adverse effects, different component yogurt starters were designed. For 2-component yogurt starters consisting of an S. thermophilus sensitive and a Lactobacillus delbrueckii ssp. bulgaricus strain, phage infection was destructive. Phages resulted in increased fermentation time, unbalanced cocci to rod ratios, decreased viscosity values, and varied sensory properties. For 3-component yogurt starters consisting of S. thermophilus sensitive, S. thermophilus insensitive, and L. bulgaricus strains, phage invasion did not result in the undesirable effects of slow acidification, decreased viscosity values, and unbalanced cocci to rod ratios. The 3- component yogurt starter stabilized fermentation and improved the practical fermentation performance in the presence of phages. Combinations of different S. thermophilus strains in the design and use of yogurt starters should be considered.

Utilization of waste cation exchange resin to prepare carbon/iron composites for the adsorption of contaminants in water

Qianqian Shi,Aimin Li,Qing Zhou,Chendong Shuang,Yan Li,Yan Ma 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.6

Carbon/iron composites were prepared from waste cation exchange resin by NaOH activation. The BETsurface areas were over 1200 m2 g-1. The presence of iron led to the formation of new mesopores andmacropores. Activation temperature had a significant impact on the pore size distributions, crystalstructures, and magnetic properties of the carbon composites, and the magnetic properties of thecomposites were related to their crystal structures. The composite synthesized at 800 8C (800ACS-1)could effectively remove diethyl phthalate, bisphenol A, and malachite green from aqueous solutions. 800ACS-1 also exhibited high stability over a wide pH range of 4–11.5.

Identification and characterization of a novel light-induced promoter for recombinant protein production in Pleurotus ostreatus

Chaomin Yin,Xiuzhi Fan,Kun Ma,Zheya Chen,Defang Shi,Fen Yao,Hong Gao,Aimin Ma 한국미생물학회 2020 The journal of microbiology Vol.58 No.1

A lectin gene (plectin) with a high level of expression was previously identified by comparative transcriptome analysis of Pleurotus ostreatus. In this study, we cloned a 733-bp DNA fragment from the start codon of the plectin gene. Sequence analysis showed that the plectin promoter (Plp) region contained several eukaryotic transcription factor binding motifs, such as the TATA-box, four possible CAAT-box, light responsiveness motifs and MeJA-responsiveness motifs. To determine whether the Plp promoter was a light-regulated promoter, we constructed an expression vector with the fused egfp-hph fragment under the control of the Plp promoter and transformed P. ostreatus mycelia via Agrobacterium tumefaciens. PCR and Southern blot analyses confirmed the Plpegfp- hph fragment was integrated into the chromosomal DNA of transformants. qRT-PCR, egfp visualization, and intracellular egfp determination experiments showed the Plp promoter could be a light-induced promoter that may be suitable for P. ostreatus genetic engineering. This study lays the foundation for gene homologous expression in P. ostreatus.

Experimental and Mechanism Investigation on Boiling Heat Transfer Characteristics of Alumina/Water Nanofluid on a Cylindrical Tube

Hao Zhang,Zeng-en Li,Shan Qing,Zhuangzhuang Jia,Jiarui Xu,Lin Ma,Sixian Wang,Aimin Zhang,Zhumei Luo 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.10

Nucleate pool boiling heat transfer experiments have been conducted to nanofluids on a horizontal cylinder tube under atmospheric pressure. The nanofluids are prepared by dispersing Al2O3 nanoparticles into distilled water at concentrations of 0.001, 0.01, 0.1, 1 and 2 wt.% with or without sodium, 4-dodecylbenzenesulfonate (SDBS). The experimental results showed that: nanofluids at lower concentrations (0.001 wt.% to 1 wt.%) can obviously enhance the pool boiling heat transfer performance, but signs of deterioration can be observed at higher concentration (2 wt.%). The presence of SDBS can obviously enhance the pool boiling heat transfer performance, and with the presence of SDBS, a maximum enhancement ratio of BHTC of 69.88%, and a maximum decrease ratio of super heat of 41.12% can be found in Group NS5 and NS4, respectively. The tube diameter and wall thickness of heating surface are the influential factors for boiling heat transfer coefficient. Besides, we find that Rohsenow formula failed to predict the characteristics of nanofluids. The mechanism study shows that: the decrease of surface tension, which leads to the decrease of bubble departure diameter, and the presence of agglomerates in nanofluids are the reasons for the enhanced pool boiling heat transfer performance. At higher concentration, particle deposition will lead to the decrease of distribution density of the vaporization core, and as a result of that, the boiling heat transfer performance will deteriorate.

Comparing the sugar profiles and primary structures of alkali-extracted water-soluble polysaccharides in cell wall between the yeast and mycelial phases from Tremella fuciformis

Hanyu Zhu,Yuan Yuan,Juan Liu,Liesheng Zheng,Liguo Chen,Aimin Ma 한국미생물학회 2016 The journal of microbiology Vol.54 No.5

To gain insights into dimorphism, cell wall polysaccharides from Tremella fuciformis strains were obtained from alkaliextracted water-soluble fractions PTF-M38 (from the mycelial form), PTF-Y3 and PTF-Y8 (from the yeast form) of T. fuciformis strains were used to gain some insights into dimorphism study. Their chemical properties and structural features were investigated using gel permeation chromatography, gas chromatography, UV and IR spectrophotometry and Congo red binding reactions. The results indicated that the backbones of PTF-M38, PTF-Y3 and PTF-Y8 were configured with α-linkages with average molecular weights of 1.24, 1.08, and 1.19 kDa, respectively. PTF-M38 was mainly composed of xylose, mannose, glucose, and galactose in a ratio of 1:1.47:0.48:0.34, while PTF-Y3 and PTF-Y8 were mainly composed of xylose, mannose and glucose in a ratio of 1:1.65:4.06 and 1:1.21:0.44, respectively. The sugar profiles of PTF-M38, PTF-Y3 and PTF-Y8 were also established for further comparison. These profiles showed that all three polysaccharides contained the same sugars but in different ratios, and the carbon sources (xylose, mannose, glucose, and galactose) affected the sugar ratios within the polysaccharides.

An Improved Total RNA Extraction Method for White Jelly Mushroom Tremella fuciformis Rich in Polysaccharides

( Hanyu Zhu ),( Xueyan Sun ),( Dongmei Liu ),( Liesheng Zheng ),( Liguo Chen ),( Aimin Ma ) 한국균학회 2017 Mycobiology Vol.45 No.4

An improved method for extracting high quality and quantity RNA from a jelly mushroom and a dimorphic fungus―Tremella fuciformis which is especially rich in polysaccharides, is described. RNA was extracted from T. fuciformis mycelium M1332 and its parental monokaryotic yeast-like cells Y13 and Y32. The A260/280 and A260/230 ratios were both approximately 2, and the RNA integrity number was larger than 8.9. The yields of RNA were between 108 and 213 μg/g fresh wt. Downstream molecular applications including reverse transcriptional PCR and quantitative real-time PCR were also performed. This protocol is reliable and may be widely applicable for total RNA extraction from other jelly mushrooms or filamentous fungi rich in polysaccharides.

An Enzymolysis-Assisted Agrobacterium tumefaciens-Mediated Transformation Method for the Yeast-Like Cells of Tremella fuciformis

( Yuanyuan Wang ),( Danyun Xu ),( Xueyan Sun ),( Lisheng Zheng ),( Liguo Chen ),( Aimin Ma ) 한국균학회 2019 Mycobiology Vol.47 No.1

Agrobacterium tumefaciens-mediated transformation (ATMT), as a simple and versatile method, achieves successful transformation in the yeast-like cells (YLCs) of Tremella fuciformis with lower efficiency. Establishment of a more efficient transformation system of YLCs is important for functional genomics research and biotechnological application. In this study, an enzymolysis-assisted ATMT method was developed. The degradation degree of YLCs depends on the concentration and digestion time of Lywallzyme. Lower concentration (_0.1%) of Lywallzyme was capable of formation of limited wounds on the surface of YLCs and has less influence on their growth. In addition, there is no significant difference of YLCs growth among groups treated with 0.1% Lywallzyme for different time. The binary vector pGEH under the control of T. fuciformis glyceraldehyde-3-phosphate dehydrogenase gene (gpd) promoter was utilized to transform the enzymolytic wounded YLCs with different concentrations and digestion time. The results of PCR, Southern blot, quantitative real-time PCR (qRT-PCR) and fluorescence microscopy revealed that the T-DNA was integrated into the YLCs genome, suggesting an efficient enzymolysis-assisted ATMT method of YLCs was established. The highest transformation frequency reached 1200 transformants per 10⁶ YLCs by 0.05% (w/v) Lywallzyme digestion for 15 min, and the transformants were genetically stable. Compared with the mechanical wounding methods, enzymolytic wounding is thought to be a tender, safer and more effective method.

Effects of opening design of gas distribution plate on fluidization of the synthesis process of organosilicon monomer

Weichuan Tan,Shanlin Du,Yunfei He,Guoqiang Lv,Wenhui Ma,Aimin Xing,Jie Huang 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.8

The structure of the gas distributor was optimized to enhance the reaction rate of direct synthesis of siliconemonomers in a fluidized bed. In this work, the opening rate range was selected by the critical pressure drop ratio, andthe influences of opening ratio and the holes quantities of distribution plate on the synthesis process were systematicallystudied by numerical simulation approaches. The fluidization velocity was simplified by Reylows’ and Archimedes’ criterionnumbers. To better predict the gas-solid fluidization characteristics in the bed, the drag model was modified by thecritical fluidization velocity. In addition, the distributor performance was investigated from the perspectives of solidphase volume fraction, pressure drop change, bubble behavior and power spectrum analysis, etc. The results show thatthe distribution plate pressure drop ratio is about 0.11679 at the opening rate of 0.53%, which meets the design criterionof reducing the dissipation while increasing the fluidized quality. A high frequency and a low amplitude arise at theopening rate of 0.53%, indicating the corresponding favorable efficiency of heat and mass transfer. The maximum fluctuationrange of the solid phase distribution with =0.53% is only 1.7%, indicating that the inhomogeneity of the solidphase fraction distribution is the lowest, and the fluidization stability is improved by about 30%. Consequently, =0.53%is proposed as the best distributor configuration and enhanced the monomer synthesis efficiency.

A Rapid and Effective Colony PCR Procedure for Screening Transformants in Several Common Mushrooms

( Yuanyuan Wang ),( Danyun Xu ),( Dongmei Liu ),( Xueyan Sun ),( Yue Chen ),( Lisheng Zheng ),( Liguo Chen ),( Aimin Ma ) 한국균학회 2019 Mycobiology Vol.47 No.3

In the post-genomic era, gene function analysis has attracted much attention. Transformation is often needed to investigate gene function. In this study, an easy, rapid, reliable, and cost-effective colony polymerase chain reaction (PCR) method for screening mushroom transformants was developed: picking up a suitable amount of transformant’s tissue (1-10 lg) to 20 ll 0.25% Lywallzyme solution, and vortexing for 10 s followed by incubation at 34 ℃ for 15 min. Finally, 2 ll of the suspension was used as templates to perform PCR and single target bands were successfully amplified from respective transformants of Tremella fuciformis, Pleurotus ostreatus, and Pleurotus tuber-regium. This procedure could be widely employed for screening transformants in mushroom transformation experiments.