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Currently, nearly 36.5 million people live with Alzheimer’s disease worldwide, and acetylcholinesterase inhibition is considered the main treatment strategy against it. Seaweeds (or macroalgae) are a natural source of high-value bioactive compounds and have great potential in the production of health foods/foods, pharmaceuticals, cosmetics, animal feeds, biofertilizers, and biofuels. The most studied and applied seaweed species include red seaweed (Rhodophyta), green seaweed (Chlorophyta) and brown seaweed (Phaeophyta). This study aimed to evaluate the antioxidant and neuroprotective activities of extracts/substances isolated with solvents including ethanol 75o and 96o, water, n-hexane, ethyl acetate under normal and ultrasonic conditions (power 80W, frequency 4.7 kHz and for 1 hour) from 5 economically important seaweed species belonging to genera Caulerpa, Sargassum, Gracilaria, Ulva and Kappaphycus collected in Ninh Thuan and Khanh Hoa provinces, Vietnam. The results have shown that 05/30 extracts and substances (including SaE96S, SaH, SaHW, SaEA and fucosterol) isolated from five seaweed species exhibited high antioxidant activity through the free radical screening method using 2,2-diphenyl-1-picrylhydrazyl (DPPH) (with EC50 values < 5 mg/mL for extracts and EC50 value < 2 mM for substance) in comparison with positive control ascorbic acid (EC50 = 0.015 mg/mL); acetylcholinesterase inhibitory activity using acetylcholinesterase inhibitor screening KIT (with IC50 values of < 200 µg/mL for both extracts and substances), compared with positive control galantamine (with IC50 value of 52,8 µg/mL). The extracts/substances were able to protect the cell against cytotoxity in the C6 alzheimer’s disease cell model induced by amyloid beta-protein fragment (Aβ25-35). The results achieved from this research have proven that the extracts/substances isolated from seaweed species were a potential source of medicinal agents for the prevention and treatment of alzheimer’s disease.

The sea area of the Truong Sa Archipelago, Vietnam - outpost island region of the country has a special geographical location and plays an important role in economic development as well as security and defense of Vietnam. Here, the first time for isolation of heterotrophic marine microalgae is precious. In this paper, the results on isolation, identification, and selection of suitable culture conditions of the strain Thraustochytrium pachydermum TSL10 isolated from the sea area of Spratly Island, Truong Sa Archipelago, Vietnam in 2021 were presented. The optimal culture conditions for the growth of T. pachydermum TSL10 in the flask were M1 medium, 3% glucose, 1% yeast extract and 25 - 28 °C temperature. Dry biomass and lipid content reached the highest levels of 12.54 ± 1.23 g/L and 28.65 ± 1.11 % dry cell weight (DCW), respectively. In a 30 L fermentor, T. pachydermum TSL10 grew well in a medium containing 9% glucose and 1% industrial extract yeast. After 120 hours of cultivation, dry biomass, lipid, protein, carbohydrate, carotenoids, and astaxanthin reached the highest levels of 30.76 ± 1.32 g/L; 22.95 ± 0.28% DCW; 6.65 ± 0.19% DCW, 15.96 ± 0.021% DCW, 178.00 ± 2.43 µg/L, and 8.30 ± 0.28 µg/L, respectively. The fatty acid composition contains mainly omega - 6 and omega - 9 fatty acids, accounting for 21.69% of total fatty acids (TFA) and 34.56% of TFA. The fatty acid profile was mainly dominated by linoleic acid and oleic acid, accounting for 21.54% of TFA and 34.23% of TFA, respectively. The results showed that TSL10 biomass was suitable raw material for screening bioactive compounds.

Fucoxanthin belonging to the carotenoid family has different bioactive properties as anti-oxidant, anti-obesity, anti-diabetic, and anti-cancer effects. This study presents the results of the extraction and purification of fucoxanthin from Sargassum olygocystum Montagne, 1845 using thin-layer chromatography, column chromatography, and high-performance liquid chromatography. Furthermore, this study demonstrated the antioxidant activities, expression of antioxidant enzymes, and inhibition of acetylcholinesterase (AChE) of fucoxanthin. The chemical structure, molecular formula (C42H58O6), and molecular weight (658) of fucoxanthin were determined by nuclear magnetic resonance spectroscopy. Fucoxanthin isolated from S. olygocystum showed no cytotoxic effects, moreover, it showed potent antioxidant activity as assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method (with an IC50 value of 3.42 ± 0.15 mg mL− 1), and AchE inhibitory activity (with an IC50 value of 130.12 ± 6.65 µg mL− 1). At concentrations of 50 and 100 µg mL− 1, fucoxanthin protected against amyloid β-protein fragment 25–35 - induced neurotoxicity on the C6 neuronal cell line with the survival of C6 cells higher than 81.01 and 80.98%, respectively, compared to the control group (59%). Moreover, antioxidant enzyme activity and quantitative PCR analysis revealed that the neuroprotective effect of fucoxanthin, was possibly due to not only regulation of gene expression of antioxidant enzyme (CAT and GPx), ER pathway (caspase-3 and Bax) but also promoting expression of genes involved in PI3K/Akt signaling (GSK-3β), autophagy (p62 and ATG5) and the biosynthesis of ACh (VAChT and ChAT). Therefore, fucoxanthin extracted from the Sargassum olygocystum is a potential feedstock source for the production of health foods with neuroprotective effects.

One new indol, N-methoxymethyltryptophol (1), one new phenolic, (2 R)-2-(4-hydroxyphenyl)ethyl 2-hydroxy-3-phenylpropanoate (2) and fifteen known compounds (3–17) were isolated from the methanol extract of the fermentation of marine microalgae Aurantiochytrium sp. SC145. Their structures were elucidated by 1D-, 2D-NMR spectroscopic analysis, HR-ESI-MS, quantum chemical calculation methods and by comparing their NMR data with those reported in the literature. All compounds were evaluated for their antimicrobial activities against microorganisms. Compounds 2, 3 and 11 significantly exhibited antimicrobial activities on all tested Gram-(+), Gram-(-) bacteria and the yeast C. albicans with MIC values ranging from 32 to 256 µg/mL.

Spirulina cyanobacteria have been widely cultivated to exploit products such as crude protein, vitamins, phycocyanin pigment... with high nutritional and pharmacological values. However, the commercialization of these products is still a challenging issue due to high biomass cost, which is mainly caused by expensive nutrients in the culture medium. In this study, from 11 freshwater S. platensis strains, by culture screening, we found 7 strains being capable of profitable growth on inexpensive seawater with salinity ranging from 5 - 30‰, and selected ST strain as the potential strain for further study. Natural seawater must be pretreated to remove ions that easily cause precipitation of nutrients in the culture medium such as Mg2+, Ca2+, SO42-… before using. The ST strain showed the best growth in the natural seawater medium with 30‰ salinity containing 3 g/L NaNO3, 0.5 g/L K2HPO4, 0.05 g/L FeSO4. This strain reached the highest biomass yield at 0.487 g/L and the specific growth rate (µ) of 0.12 x day-1; protein and phycocyanin contents reached 48.6% and 127 mg/g of dry biomass, respectively. There was no difference in the mentioned above values with biological statistical significance between this medium and SOT medium in distilled water. The ST strain biomass was qualified to be used for the production of functional foods. Results of this study provided scientific basis for the use of marine and brackish waters to produce biomass of this highly economic cyanobacterium.

Thraustochytrium is a heterotrophic marine microalgae genus belonging to the Labyrinthula class, Thraustochytriaceae (Thraustochytrids) family. Recently, studied results have showed that some species/strains of Thraustochytrium genus are potential candidates to produce biomass rich in lipid containing high polyunsaturated fatty acid (PUFAs), especially docosahexaenoic (DHA C22: 6 ω-3), carotenoid, extracellular polysaccharides (EPSs) and enzymes which play a crucial role in human health. Therefore, throughout many decades, numerous studies have been conducted in exploiting bioactive compounds, especially PUFAs. Biomass and PUFAs yield of some strains Thraustochytrium spp. depend on environmental conditions. In this paper, the results on the effects of different culture conditions on the growth of Thraustochytrium aureum BT6 (isolated from coastal regions of Binh Thuan in 2010) in 500 mL erlenmeyer flask and 30 L fermentors is presented. Suitable conditions for the growth of strain BT6 were: Bajpai medium, 2% glucose, 0.5% yeast extract, temperature of 20−28 oC, salt concentration 0.5%; and initial algal cell concentration of 2 g/L. The dry biomass, lipid and DHA contents of strain BT6 in 500 mL erlenmeyer flasks and 30 L fermentor reached the highest levels of 8.56 ± 0.12 and 6.92 ± 0.27 g/L, 18.36 ± 1.15 and 5.50 ± 0.133% DCW, 2.00 ± 0.05 and 0.14 ± 0.01% DCW, respectively, after 4 days of cultivation. Carotenoid content in flask and 30L fermentor achieved 44.45 ± 1.4 and 28.84 ± 1.12 mg/kg DCW, respectively after 4 days of cultivation. Obtained results have indicated that the algae biomass met the requirements in orientation to exploit valuable bioactive compounds.

Objectives Isolation, structure determination, and antimicrobial activities evaluation of compounds from the methanol extract of the marine microalga Thraustochytrium pachydermum TSL10. Methods Using chromatographic methods to isolate compounds from the methanol extract of the T pachydermum. The chemical structures were elucidated by analyses of HR-ESI-MS and NMR spectral data. The antimicrobial activities of compounds were evaluated using the dilution turbidimetric broth method as the standard protocol published by the Clinical and Laboratory Standard Institute. Results One new sterol, (24 R)-ergosta-7,22-diene-3 β,5 α,9 α-triol (1), and 16 known compounds, ergosta-7,22-diene-3 β,5 α-diol (2), cerevisterol (3), (22 E,24 S)-5 α,6 α-epoxy-ergosta-8(9),22-diene-3 β,7 α-diol (4), ergosterol (5), 5 α,8 α-epidioxyergosta-6,22-diene-3 β-ol (6), linoleic acid (7), 4-((9 Z,12 Z)-octadeca-9,12-dienoyloxy)butanoic acid (8), 1-linoleoyl-sn-glycero-3-phosphocholine (9), cibotiglycerol (10), gingerglycolipid B (11), oleic acid (12), 4-((9Z)-octadec-9-enoyloxy)butanoic acid (13), (2 S)-1- O-(9 Z)-octadec-9-enoyl)-3- O-(6-sulfo-D-quinovopyranosyl)glycerol (14), 6′- O-linoleylsucrose (15), gingerglycolipid C (16), and ( S)-3-stearoyl- sn-glycerol (17) were identified from the marine microalga Thraustochytrium pachydermum TSL10. Sterols 1–6 were found to exhibit significant antimicrobial activities on Gram-( + ) bacteria ( Enterococcus faecalis ATCC29212 , Staphylococcus aureus ATCC25923, and Bacillus cereus ATCC14579) and the yeast ( Candida albicans ATCC10231) with MIC values ranging from 32 to 256 µg/mL. Conclusions The results suggested sterols 1–6 could be potential antimicrobial agents against Gram-( + ) bacteria.

Green macroalgae have gained attention as promising renewable sources for biorefining. Despite the wide potential availability of green macroalgae, their utilization has been limited to ethanol production, hindering their further application. In this study, we report that a bacterium, Halomonas sp. strain BL6 (isolated from a mangrove forest in Bach Long, Nam Dinh Province, Vietnam), produces pyruvate from a saccharified solution of the green seaweed Ulva reticulata and secretes it into the medium. Pyruvate, an important α-oxocarboxylic acid, plays a central role in energy and carbon metabolism in living organisms and is used mainly for the synthesis of various chemicals and polymers or as an ingredient or additive in food, cosmetics, and pharmaceuticals. To investigate the possibility of using U. reticulata from the seashore of Vietnam as biomass feedstock, the chemical composition and saccharification yield of this seaweed were studied. Dry biomass of U. reticulata was found to contain 65.5% carbohydrate, 10.3% protein, 1.8% lipid, and 10.6% ash. Reducing sugar content reached 608.79 mg g−1 of biomass after pretreatment with diluted acid and 24 h of incubation with 50 IU g−1 Viscozyme L. The resulting sugars were fermented by Halomonas sp. strain BL6 to produce pyruvate, and the maximal pyruvate concentration reached 55.23 g L−1 after 72 h of cultivation. This study is the first to report the production of valuable compounds other than bioethanol products, such as pyruvate, from U. reticulata hydrolysate by a Halomonas strain.

In this work, polypyrrole (PPy) films were directly deposited on Al2O3 substrate by a facile template-free vapour phase polymerization route using ferric chloride (FeCl3) oxidant. Influence of the surface morphology and doping of the PPy structures on the gas sensing performance was investigated. The synthesized PPy films with different morphologies including nanoparticles-cluster, nanofibers-matrix and porous-structure were obtained by simply regulating the utilized FeCl3 solutions in concentration range from 0.01 to 0.06 M. The increase in the used FeCl3 concentration led to a monotonous increase in the doping/oxidant content of the PPy film. Sensing performances of the PPy films were examined by investigating their resistances responding to NH3, NO2, H2, CO and CH4 gases, and relative humidity (11–95% RH) at room temperature (25 °C). All the PPy films presented to have high selectivity and reversibility to NH3 gas. The highest response to NH3 gas and the lowest humidity influence were found for the nanoparticles-cluster PPy film. The fast sensing response times of the PPy films were about 10, 7, 4 and 3 s in order of the used FeCl3 concentrations of 0.01, 0.02, 0.04 and 0.06 M, respectively. The sensing performances at room temperature of the PPy films were suggested to be attributed by both their surface morphology and doping content.

Pyruvic acid (pyruvate) is a central intermediate in carbon and energy metabolism in all organisms. It is widely used in the industrial biosynthesis of high - value compounds and food additives. Biotechnological pyruvate production has attracted attention as a potential alternative method of pyruvate synthesis. From 27 soil and mud samples collected from mangrove forests of Cam Ranh, Khanh Hoa province, we isolated 10 bacterial strains belonging to Halomonas genus. Among them, 9 strains were able to synthesis and secreted pyruvate in the culture medium. The maximal pyruvate production was in MC8 strain with value of 0.110 ± 0.015 g/L. MC8 strain was Gram-negative, short rod-shaped, 1,56 ± 0,07 in width, 5,09 ± 0,38 µm in length, non-flagella and nonmotile. MC8 strain was positive for oxidase and catalase activities and reduction of nitrate to nitrite and nitrogen. Cells were able to growth at salt concentrations of from 0.5 to 20%, temperature ranging from 20 to 45ºC and pH ranging from 5 to 12. The major fatty acids of MC8 biomass were C16:0; C18:1w7c và C12:0 3OH. Phylogenetic analyses based on 16S rRNA gene sequencing showed that MC8 strain possessed the highest similarity of 98.5% to the strain Halomonas flava. Based on morphological, biochemical characteristics and 16S rRNA gene sequencing, MC8 strain was identified as H. flava. This is the first study of Halophilic bacteria which is capable of pyruvate synthesis in Vietnam. Thus, these obtained results provided important insights into the production of pyruvate using Halomonas strains.

Pyruvic acid (pyruvate) the most important α-oxocarboxylic acid, plays a central role in energy metabo-lism in living organisms. It is used mainly as a starting material in the biosynthesis of pharmaceuticals as well as employed in the production of crop protection agents, polymers, cosmetics and food additives. Four Gram-negative, moderately halophilic, pyruvate and poly (3-hydroxybutyrate)- producing strains were isolated from soil samples collected from mangrove forest at Giao Thuy, Nam Dinh province. Preliminary screening results showed that among fours strain, the ND7 strain was able to produce the highest bioplastic-poly (3-hydroxybutyrate) (PHB) and extracellular secretion of pyruvate, respectively, reaching 50.23% dry weight and 6.87 g/L after 60 hours of cultivation. When cultured in high alkaliphilic medium (pH 9.4), the pyruvate secretion increased significantly (21.02 g/L after 60 hours of cultivation). Based on the morphological, bio-chemical characteristics and nucleotide sequence analysis of partial 16S rRNA gene, the ND7 strain was iden-tified as Halomonas maura. The results allow us to conclude that ND7 strain is a potential target for the ex-ploitation of pyruvate in a larger scale.

In this study, the genome of Thraustochytrium sp. TN22, a heterotrophic marine microalga, was sequenced, assembled and annotated using the Illumina NovaSeq 6000, PacBio RS II and MinION platform to identify genes and EPS and carotenoid biosynthesis pathways. The genome of Thraustochytrium sp. TN22 consists of 38,842,079 bp with a G + C content of 66.52% and reached 90.7% gene completeness. In total, 15,208 genes were annotated, among which 14,236 genes were identified using the NCBI-nr, KEGG, GO, COG and InterProScan databases. Pathway analysis showed that EPS biosynthesis in Thraustochytrium sp. TN22 follows an ABC-dependent pathway. The carotenoids of Thraustochytrium TN22 are predicted to be synthesized via the mevalonate pathway, and the conversion of β-carotene to xanthophyll proceeds through β-cryptoxanthin and zeaxanthin intermediates. Our results will be useful for improving high-value coproducts for industrial application of thraustochytrids.

Squalene is currently known as chemopreventive agents in reducing the incident of coronary heart disease and cancer. It is also a strong antioxidant used extensively in the food and cosmetic industries. Microbial sources of squalene are being explored in recent years. The objective of this study was to investigate fermentation conditions of Schizochytrium mangrovei PQ6 for high squalene production in 30L bioreactor. Squalene production was influenced by various nutritional factors such as glucose, nitrogen, vitamins etc. and physical factors such as batch and fed-batch fermentation. Our study established that fed-batch fermentation with nitrogen source of 1.2% yeast extract and 6.4% monosodium glutamate and 0.4% mixture of vitamin B1, 6 and 12 as optimal culture condition for maximal production of squalene by S. mangrovei PQ6. In fed-batch culture, the glucose concentration feeding was added up to 22% into the culture at 36 h of fermentation. The maximum squalene production was achieved 6.9 ± 0.1 g/L at 48 h of fed-batch fermentation, respectively. The values were 2-3 times more than that in fed-batch cultivation without adding mixture of vitamins and 4-6 times more than that in batch cultivation. Our obtained results are a breakthrough for the development of alternative squalene source from heterotrophic marine microalgae of Schizochytrium mangrovei PQ6 species for health-promoting functional foods. Citation: Nguyen Cam Ha, Hoang Thi Minh Hien, Le Thi Thom, Hoang Thi Huong Quynh, Dang Diem Hong, 2017. Optimization of fermentation conditions for squalene production by heterotrophic marine microalgae Schizochytrium mangrovei PQ6. Tap chi Sinh hoc, 39(3): 349-358. DOI: 10.15625/0866-7160/v39n3.9130. *Corresponding author: hoangminhhien@yahoo.com; ddhong60vn@yahoo.com Received 6 January 2017, accepted 20 August 2017

This study introduces an effective method of decorating noble metal palladium (Pd) nanoparticles on the surface of polyaniline (PANi) to enhance NH3 gas-sensing performance. The surface structure analysis conducted through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the diameters of the synthesized PANi nanowires were 50–100 nm. The chemical composition structure of the PANi composites was studied by Raman spectroscopy. Energy-dispersive X-ray spectroscopy (EDS) was applied to identify the composition of modified Pd on the PANi composite surface. The obtained results demonstrate the applicability of the PANi composites to improve the sensitivity, response time, and recovery time of NH3 gas sensors.

In this work, NO 2 sensing characteristics of the sensors based on Schottky contacts between metal electrodes (Au, Pt) and nanotube titanates (Na x H 2 −x Ti 3 O 7 ) for room temperature operation were investigated. The nanotube titanates (NTT) with 10 nm in diameter were synthesized by a typical hydrothermal method. The sensors were fabricated with different configurations of Pt/NTT/Pt, Au/NTT/Au and Au/NTT/Pt for analyzing effect of the Schottky contacts (Au, Pt)/NTT on gas-sensing performance. The NO 2 sensing results of the sensors indicated that the synthesized nanotube titanates were p-type semiconductor and the interface Au/NTT had large NO 2 sensitivity in comparison with the interface Pt/NTT. High selectivity of the sensor Au/NTT/Pt to NO 2 gas was also presented by cross-sensing investigation to some gases such as NO, NH 3 , H 2 , CO and C 3 H 8 . Additionally, it was found that the sensor Au/NTT/Pt exhibited high sensitivity and fast response/recovery times in low concentration range of NO 2 gas (0–10 ppm) at room temperature. The gas sensing mechanism of the sensors was explained by change in the Schottky barriers (Au, Pt)/NTT when interacting with reducing/oxidizing gases.

Halophilic bacteria are receiving increasing attention for industrial chemical production processes due to their unique properties. Herein, an alkaliphilic and halophilic bacterium was isolated from a commercial Spirulina culture at Nghe An province in Vietnam and found to secrete pyruvate. Pyruvate is widely used as a starting material in the industrial biosynthesis of pharmaceuticals, and is employed for production of crop protection agents, polymers, cosmetics, and food additives. Phenotypic and chemotaxonomic characterization, and the 16S rRNA gene sequence homology with Halomonas hydrothermalis strain DSM 15,725 (99.2%) predicted that the strain belongs to the Halomonas genus, thus we named this strain as H. hydrothermalis strain C22. We investigated the biocharacteristics and capacity of strain C22 and determined the draft genome sequence comprising 3,934,166 bp with a G + C content of 60.2% encoding 3,668 proteins, 58 tRNAs, 9 rRNAs, and 1 tmRNA. Maximal pyruvate secretion reached 51.1 g/l after 84 h of cultivation. The results will facilitate future studies on the genetic and metabolic diversity of halophilic bacteria and expand our understanding of important bioprocesses in this microorganism.

In this paper, the acute and subchronic toxicity and the effect of squalene isolated from heterotrophic marine microalga Schizochytrium mangrovei PQ6 on the serum levels of HDL-C were investigated using animal models. The results of acute toxicity study showed that by oral administration of the squalene on albino mice at the highest dose of 58.25 g/kg of whole body of mice/day, the LD50 was not determined. Squalene at doses of 400 mg and 1,200 mg/kg/day for 60 consecutive days have allowed the normal behavior, body weight, hematological and biochemical parameters, liver and kidney functions, morphology of liver, kidney and spleen, total plasma cholesterol content, however, HDL-C level was higher in squalene treated mices compared to control group (p < 0.05). In addition, at doses of 600 and 1,200 mg/kg/day for 60 continuous days, squalene treated mice showed the increase in HDL-C level and HDL-C/total cholesterol ratio and the decrease in the contents of LDL-C and VLDL-C without affecting the body and liver weights and levels of total cholesterol and triglyceride.

In this work, NiO/PPy hybrid nanostructured films were fabricated by chemical vapor-phase polymerization using NiO nanoparticles films drop-coated FeCl3 oxidant on Al2O3 substrates. The NiO nanoparticles with a size of about 20 nm were synthesized by a hydrothermal method. Different ratios between NiO and PPy in the NiO/PPy hybrid films were modified by regulating FeCl3 oxidant content when using FeCl3 solutions with concentrations of 0.15, 0.2, 0.4, 0.8, and 1.5 M. X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy, and Raman scattering spectroscopy were used to analyze specific material characteristics of these films. The gas-sensing performance of the films was examined by exploring their resistances responding to NH3, NO2, H2, CO, and relative humidity at an operating temperature range from 25 to 110 °C. The NiO/PPy hybrid films presented to have a very high sensitivity to NH3 gas in comparison to the non-hybrid films based on only NiO or PPy. The highest sensitivity to NH3 gas (the sensing response S = 246.6 % for 350 ppm at 25 °C) was found for the NiO/PPy film with the used 0.2 M FeCl3 oxidant solution. The gas-sensing performance of the NiO/PPy films was suggested by the main contribution of the hybrid nanostructure between NiO nanoparticles and PPy.

In this study, an effective electrochemical method was successfully developed to produce polyaniline/multiwalled carbon nanotubes nanocomposite on interdigitated platinum microelectrodes for the enhancement of biosensing performance. Morphology and structure of nanocomposite were investigated by field emission scanning electron microscopy and ultraviolet–visible spectroscopy. Fourier transform infrared spectroscopy technique was used to identify the presence of polyaniline/multiwalled carbon nanotubes on the surface of microelectrodes. IgG polyclonal antibodies against Japanese encephalitis virus (JEV) were immobilized onto nanocomposite-modified microelectrodes, acting as an electrochemical immunosensor for label-free detection of JEV antigens. Results showed that the linear detection range of the immunosensor for JEV antigens was 2–250 ng/mL. The electrochemical impedance spectroscopy analysis also indicated that a negligible response was found when the immunosensor exposed to non-specific molecules. This work showed the potential use of polyaniline/multiwalled carbon nanotubes nanocomposite in the platform of electrochemical immunosensors for label-free detection of pathogens and small biomolecules.

Seaweed is rich source of natural bioactive compounds that could be exploited as functional ingredient for cosmetic applications. The aim of this study was to evaluate the biochemical compositions and bioactivities of 10 seaweeds collected from coastal waters of Vietnam. The present study also prepared and evaluated cream mask from mixture of seaweeds extracted with water. The results showed that

To examine the effect of squalene on liver X receptors (LXRs) that regulate target genes associated with reverse cholesterol transport and thus control whole-body cholesterol homeostasis. To examine the effect of squalene on liver X receptors (LXRs) that regulate target genes associated with reverse cholesterol transport and thus control whole-body cholesterol homeostasis. Squalene significantly stimulated the transactivation of liver X receptor modulator LXRα and LXRβ. The mRNA expression of LXRs and their target genes, including ABCA1, ABCG1 and ApoE, was significantly induced in macrophages stimulated with squalene, resulting in removal of cholesterol from the cells. Notably, squalene did not induce higher hepatic triacylglycerol levels nor did it alter expression of sterol regulatory element-binding protein 1c (SREBP-1c) and FAS in hepatocyte cells, primarily because of its upregulation of Insig-2a, which delays nuclear translocation of SREBP-1c, a key hepatic lipogenic transcription factor. Squalene has hypocholesterolemic effect through the activation of LXRα and β without inducing hepatic lipogenesis.

Vietnamese edible marine macro-algae (seaweed) are of interest because of their value in nutrition and medicine. Vietnamese living in the coastal have traditionally utilized seaweeds species as food supplement and herbal medicine. They consumed seaweed as food in various forms: raw as salad and vegetable, pickle with sauce or with vinegar, relish or sweetened jellies and also cooked for vegetable soup. As herbal medicine, seaweed is usually used for traditional comestics, treatments for cough, asthma, hemorrhoid, boils, goitres, stomach ailments, urinary diseases, reduce the incidence of tumors, ulcers and headaches. Although Vietnam has an abundance of algae floral with total number of species is estimated to be nearly 1000 spp. in which there are 638 species of marine algae identified. However, there have been no intense study regarding to changes in marine algal chemistry. The fifteen species of edible seaweeds studied in this paper include green, brown and red algae. The proximate compositions as ash, protein, lipid, carbohydrate, fatty acids, vitamines, pigments, macro and micro-elements were compared among different species examined and the genetic relationships among them by analyzing the species-specific differences in nucleotide sequences of ITS-1 region of the ribosomal DNA was identified.

Some species of marine dinoflagellates belonging to genera Alexandrium and Prorocentrum have been responsible for paralytic shellfish poisoning (PSP) and diarrheic shellfish poisoning (DSP), respectively Morphological and molecular studies of 4 species including Alexandrium sp. 5, Alexandrium sp. 16, Prorocentrum sp. 1 and Prorocentrum sp. 3 that were collected in Northern coast of Vietnam were presented for the first time. By morphologic observations, we identifiedAlexandrium sp. 5 and Alexandrium sp. 16 as Alexandrium minutum, Alexandrium affine, respectively; Prorocentrum sp. 1 and Prorocentrum sp. 3 as Prorocentrum mexicanum. Sequence data from the partial 18S riboxomal RNA genes have been used to generate a phylogenetic framework with database of GenBank. The obtained results of phylogenetic analyses of species of Prorocentrum spp. and Alexandrium spp. based on 18S rDNA sequences are similar to morphological observations. Thus, molecular tool would be helpful for the identification of dinoflagellate species and further taxonomic studies in Vietnam.