Two new species of Camellia (Theaceae) from Vietnam

Lieu Thi Nguyen,Ninh Tran,Uematsu CHIYOMI,Katayama HIRONORI,Dung Van Luong,Son Thanh Hoang,Ky Danh NGUYEN,Hung Viet NGUYEN,Toan Canh THAI 한국식물분류학회 2018 식물 분류학회지 Vol.48 No.2

Two new species of Camellia (Theaceae) are described from Vietnam: Camellia vuquangensis Luong, Tran & L. T. Nguyen and Camellia hatinhensis Luong, Tran & L. T. Nguyen. The new taxa were col- lected from Vu Quang National Park in the center of Vietnam. The new finds are morphologically dissimilar to all known Camellia species. Recent Camellia discoveries have increased the number of species recorded in Viet- nam from 50 to 75, making Vietnam a center of diversity and a crucial area for more research into the diversity and distributions of Camellia.

Effect of Lactic Fermentation and Spray Drying Process on Bioactive Compounds from Ngoc Linh Ginseng Callus and Lactobacillus plantarum Viability

( Lieu My Dong ),( Nguyen Thi Thuy Linh ),( Nguyen Thi Hoa ),( Dang Thi Kim Thuy ),( Do Dang Giap ) 한국미생물 · 생명공학회 2021 한국미생물·생명공학회지 Vol.49 No.3

Ngoc Linh ginseng is one of the most valuable endemic medicinal herbs in Vietnam. In this study, Ngoc Linh ginseng callus was fermented by Lactobacillus plantarum ATCC 8014 (at 6, 7, and 8 log CFU/ml) to evaluate the extraction efficiency of bioactive compounds. The post-fermentation solution was spray-dried using maltodextrin with or without Stevia rebaudiana (3% and 6% v/v) as the wall material. Bioactive compounds such as polyphenols, polysaccharides, and total saponins, and L. plantarum viability during fermentation and after spray-drying, as well as under simulated gastric digestion, were evaluated in this study. The results showed that probiotic density had a significant effect on bioactive compounds, and L. plantarum at 8 log CFU/ml showed the best results with a short fermentation time compared to other tests. The total content of polyphenols, polysaccharides, and saponins reached 5.16 ± 0.18 mg GAE/g sample, 277.2 ± 6.12 mg Glu/g sample, and 4.17 ± 0.15 mg/g sample, respectively after 20 h of fermentation at the initial density of L. plantarum (8 log CFU/ml). Although there was no difference in the particle structure of the preparation, the microencapsulation efficiency of the bioactive compound in the samples containing S. rebaudiana was higher than that with only maltodextrin. The study also indicated that adding S. rebaudiana improved the viability of L. plantarum in gastric digestion. These results showed that S. rebaudiana, a component stimulating probiotic growth, combined with maltodextrin as a co-prebiotic, improved the survival rate of L. plantarum in simulated gastric digestion.

Enhancing the Viability Rate of Probiotic by Co-Encapsulating with Prebiotic in Alginate Microcapsules Supplemented to Cupcake Production

Lieu My Dong,Nguyen Thien Luan,Dang Thi Kim Thuy 한국미생물·생명공학회 2020 한국미생물·생명공학회지 Vol.48 No.2

The objective of the study was to assess the survival of microencapsulated Lactobacillus plantarum ATCC8014 produced using the emulsion technique in alginate gel combined with pectin and maltodextrin components. The microcapsules were then added to cupcake dough that was further baked at 200℃ for 12 min. The viability of L. plantarum was assessed during baking and the 10 days of storage at 4℃ as well as in simulated gastrointestinal conditions. In addition, yeast-mold and water activity were investigated. After baking, the samples with microencapsulated L. plantarum contained more than 5 log CFU/g, which was higher compared to the bacterial concentration of the control samples. The concentration of L. plantarum was more than 6 logs CFU/g after the end of the storage; therefore, the probiotic functioned as a biopreservative in the cake. The prebiotic component strengthened the microcapsules network and helped protect the viability of L. plantarum in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) media. The results show that the addition of L. plantarum microencapsules did not affect the sensory scores of the cupcake while ensuring the viability of the probiotic during baking and storing.

Improvement of Anthocyanin Encapsulation Efficiency into Yeast Cell by Plasmolysis, Ethanol, and Anthocyanin Concentration Using Response Surface Methodology

( Lieu My Dong ),( Hoang Thi Thuy Hang ),( Nguyen Huyen Nguyet Tran ),( Dang Thi Kim Thuy ) 한국미생물 · 생명공학회 2020 한국미생물·생명공학회지 Vol.48 No.3

Anthocyanins are antioxidant compounds susceptible to environmental factors. Anthocyanin encapsulation into yeast cells is a viable solution to overcome this problem. In this study, the optimal factors for anthocyanin encapsulation were investigated, including anthocyanin concentration, plasmolysis contraction agent, and ethanol concentration, and response surface methodology was evaluated, for the first time. Anthocyanin from Hibiscus sabdariffa L. flowers was encapsulated into Saccharomyces cerevisiae using plasmolysis contraction agent (B: 3%-20% w/v), ethanol concentration (C: 3%-20% v/v), and anthocyanin concentration (A: 0.15-0.45 g/ml). The encapsulation yield and anthocyanin loss rate were determined using a spectrometer (520 nm), and color stability evaluation of the capsules was performed at 80℃ for 30 min. The results of the study showed that these factors have a significant impact on the encapsulation of anthocyanin, in which ethanol agents have the highest encapsulation yield compared to other factors in the study. Statistical analysis shows that the independent variables (A, B, C), their squares (A², B², C²), and the interaction between B and C have a significant effect on the encapsulation yield. The optimized factors were anthocyanin, 0.25 g/ml; NaCl, 9.5% (w/v); and ethanol, 11% (v/v) with an encapsulation yield of 36.56% ± 0.55% and anthocyanin loss rate of 15.15% ± 0.98%; This is consistent with the expected encapsulation yield of 35.46% and loss rate of 13.2%.

Microprocessor depends on hemin to recognize the apical loop of primary microRNA

Nguyen, Tuan ,Anh,Park, Joha,Dang, Thi ,Lieu,Choi, Yeon-Gil,Kim, V ,Narry Oxford University Press 2018 Nucleic acids research Vol.46 No.11

<P><B>Abstract</B></P><P>Microprocessor, which consists of a ribonuclease III DROSHA and its cofactor DGCR8, initiates microRNA (miRNA) maturation by cleaving primary miRNA transcripts (pri-miRNAs). We recently demonstrated that the DGCR8 dimer recognizes the apical elements of pri-miRNAs, including the UGU motif, to accurately locate and orient Microprocessor on pri-miRNAs. However, the mechanism underlying the selective RNA binding remains unknown. In this study, we find that hemin, a ferric ion-containing porphyrin, enhances the specific interaction between the apical UGU motif and the DGCR8 dimer, allowing Microprocessor to achieve high efficiency and fidelity of pri-miRNA processing <I>in vitro</I>. Furthermore, by generating a DGCR8 mutant cell line and carrying out rescue experiments, we discover that hemin preferentially stimulates the expression of miRNAs possessing the UGU motif, thereby conferring differential regulation of miRNA maturation. Our findings reveal the molecular action mechanism of hemin in pri-miRNA processing and establish a novel function of hemin in inducing specific RNA-protein interaction.</P>

Enhancing the Viability Rate of Probiotic by Co-Encapsulating with Prebiotic in Alginate Microcapsules Supplemented to Cupcake Production

Dong, Lieu My,Luan, Nguyen Thien,Thuy, Dang Thi Kim The Korean Society for Microbiology and Biotechnol 2020 한국미생물·생명공학회지 Vol.48 No.2

The objective of the study was to assess the survival of microencapsulated Lactobacillus plantarum ATCC8014 produced using the emulsion technique in alginate gel combined with pectin and maltodextrin components. The microcapsules were then added to cupcake dough that was further baked at 200℃ for 12 min. The viability of L. plantarum was assessed during baking and the 10 days of storage at 4℃ as well as in simulated gastrointestinal conditions. In addition, yeast-mold and water activity were investigated. After baking, the samples with microencapsulated L. plantarum contained more than 5 log CFU/g, which was higher compared to the bacterial concentration of the control samples. The concentration of L. plantarum was more than 6 logs CFU/g after the end of the storage; therefore, the probiotic functioned as a biopreservative in the cake. The prebiotic component strengthened the microcapsules network and helped protect the viability of L. plantarum in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) media. The results show that the addition of L. plantarum microencapsules did not affect the sensory scores of the cupcake while ensuring the viability of the probiotic during baking and storing.

Camellia tuyenquangensis (Theaceae), a new species from Vietnam

Ninh Nguyet Hai Le,Chiyomi Uematsu,Hironori Katayama,Lieu Thi Nguyen,Ninh Tran,Dung Van Luong,Son Thanh Hoang 한국식물분류학회 2017 식물 분류학회지 Vol.47 No.2

Camellia tuyenquangensis (Theaceae), a new yellow species of camellia from the Chiem Hoa district of the Tuyen Quang province in Vietnam, is described and illustrated. Camellia tuyenquangensis is similar to Camellia luongii but different from the latter species in several morphological features: leaves oblong-ovate to narrow elliptic; flowers 1–2; bracteoles glabrous on both sides; sepal margins ciliate; style cleft one half of the length. The morphological data provisionally support its placement in Camellia sect. Chrysantha Chang.