Chemical constituents from the heterotrophic marine microalgae Aurantiochytrium sp. SC145 and their antimicrobial activities.

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.

Isolation of Fucoxanthin from Sargassum oligocystum Montagne, 1845 Seaweed in Vietnam and Its Neuroprotective Activity.

Fucoxanthin extracted and purified from Vietnamese Sargassum oligocystum Montagne, 1845 exhibits various biological activities. In this study, the ability of fucoxanthin to inhibit acetylcholinesterase (AChE), the antioxidant activities, and the expression of antioxidant enzymes were investigated. Fucoxanthin isolated from Vietnamese S. oligocystum showed no cytotoxic effects; moreover, it exhibited AChE inhibitory activity (with an IC50 value of 130.12 ± 6.65 µg mL-1) and antioxidant activity (with an IC50 value of 3.42 ± 0.15 mg mL-1). At concentrations of 50 and 100 µg mL-1, fucoxanthin provided protection against amyloid ß-protein fragment 25-35-induced neurotoxicity in a C6 neuronal cell line, and the survival of C6 cells was higher than 81.01% and 80.98%, respectively, compared to the control group (59%). Moreover, antioxidant enzyme activity and quantitative PCR analysis suggested that the neuroprotective effect of fucoxanthin resulted from regulation of the gene expression of antioxidant enzymes (CAT and GPx) and ER pathways (caspase-3 and Bax), as well as the promotion of expression of genes involved in PI3K/Akt signaling (GSK-3ß), autophagy (p62 and ATG5), and the biosynthesis of ACh (VAChT and ChAT). Therefore, fucoxanthin extracted from the seaweed S. oligocystum in Vietnam is a potential feedstock source for the production of health foods that exert neuroprotective effects.

Novel human STING activation by hydrated-prenylated xanthones from Garcinia cowa.

OBJECTIVES: We investigate the anticancer activity and human stimulator of interferon genes pathway activation by a new hydrated-prenylated tetraoxygenated xanthone, garcicowanone I (1) and two known xanthones (2 and 3) that were isolated from the root bark of Garcinia cowa Roxb. ex Choisy. METHODS: The anticancer activity of each compound was evaluated by sulforhodamine B assay in immortalized cancer cell lines. Stimulator of interferon genes pathway activation was assessed by western blot analysis using human THP-1-derived macrophages. The production of pro-inflammatory cytokines from these macrophages was also evaluated via enzyme-linked immunosorbent assay. KEY FINDINGS: Both compounds 1 and 3 displayed moderate inhibitory effects on the cancer cells, including a cisplatin-resistant cell line, with IC50 values in the range of 10-20 µM. All three xanthones activated the stimulator of interferon genes, as evidenced by phosphorylation of tank-binding kinase 1, the stimulator of interferon genes protein and interferon regulatory factor 3. Furthermore, treatment of these macrophages with compounds 1-3 led to the production of pro-inflammatory cytokines, including interleukin 6, tumour necrosis factor α and interleukin 1ß. CONCLUSIONS: In conclusion, the isolated xanthones, including the novel garcicowanone I, displayed promising anticancer and immunomodulatory activity that warrants further research.

Characterization and Optimization of Culture Conditions for Aurantiochytrium sp. SC145 Isolated from Sand Cay (Son Ca) Island, Vietnam, and Antioxidative and Neuroprotective Activities of Its Polyunsaturated Fatty Acid Mixture.

Aurantiochytrium is a heterotrophic marine microalga that has potential industrial applications. The main objectives of this study were to isolate an Aurantiochytrium strain from Sand Cay (Son Ca) Island, Vietnam, optimize its culture conditions, determine its nutritional composition, extract polyunsaturated fatty acids (PUFAs) in the free (FFA) and the alkyl ester (FAAE) forms, and evaluate the antioxidation and neuroprotection properties of the PUFAs. Aurantiochytrium sp. SC145 can be grown stably under laboratory conditions. Its culture conditions were optimized for a dry cell weight (DCW) of 31.18 g/L, with total lipids comprising 25.29%, proteins 7.93%, carbohydrates 15.21%, and carotenoid at 143.67 µg/L of DCW. The FAAEs and FFAs extracted from Aurantiochytrium sp. SC145 were rich in omega 3-6-9 fatty acids (40.73% and 44.00% of total fatty acids, respectively). No acute or subchronic oral toxicity was determined in mice fed with the PUFAs in FFA or FAAE forms at different doses over 90 days. Furthermore, the PUFAs in the FFA or FAAE forms and their main constituents of EPA, DHA, and ALA showed antioxidant and AChE inhibitory properties and neuroprotective activities against damage caused by H2O2- and amyloid-ß protein fragment 25-35 (Aß25-35)-induced C6 cells. These data suggest that PUFAs extracted from Aurantiochytrium sp. SC145 may be a potential therapeutic target for the treatment of neurodegenerative disorders.

The Correlation Between Angiopoietin-Like 3 and Metabolic Markers of Some Lipid and Glucose in Type 2 Diabetes Mellitus Patients at the First Diagnosis.

Purpose: Angiopoietin-Like3 is a protein that plays an important role in regulating plasma triglyceride concentrations by inhibiting the enzyme lipoprotein lipase. Lipid metabolism and glucose metabolism are closely related and interact with each other. ANGPTL3 may also be a factor involved in blood glucose regulation through an increase in free fatty acids generated from enhanced lipolysis in adipose tissue leading to insulin resistance. This study aimed to investigate plasma ANGPTL3 concentrations and their correlation with lipid and glucose metabolic markers in newly diagnosed type 2 Diabetes Mellitus patients. Subject and Methods: A cross-sectional descriptive study was conducted on 98 healthy subjects (control group) and 103 patients with type 2 diabetes at the first diagnosis, without any treatment (patient group). Plasma ANGPTL3 concentration was quantified by the ELISA method. The study determines the correlation of ANGPTL3 concentration with some indicators reflecting lipid and glucose metabolism. Results: The concentration of ANGPTL3 in the newly diagnosed type 2 Diabetes Mellitus patient group was lower than in the control group, the difference was statistically significant with p < 0.05. In the patient group: there was an inverse correlation between ANGPTL3 concentration and HDL-C concentration (r = -0.37; p<0.001), and a positive correlation with triglyceride concentration (r = 0.275; p < 0.05). There was no correlation between plasma ANGPTL3 levels and anthropometric indices, total cholesterol, HDL-C, glucose, HbA1C, insulin, and HOMA-IR. In the control group: there was no correlation between ANGPTL3 and any of the indicators mentioned above. Conclusion: ANGPTL3 levels in newly diagnosed type 2 diabetes mellitus patients were statistically significantly lower than in healthy subjects. Plasma ANGPTL3 was positively correlated with triglyceride levels and inversely correlated with HDL-C levels in newly diagnosed type 2 Diabetes mellitus patients.

Six New Polyoxygenated Xanthones from Garcinia cowa and Their Neuroprotective Effects on Glutamate-Mediated Hippocampal Neuronal HT22 Cell Death.

Six new polyoxygenated xanthones, garcicowanones F-H (1-3), norcowanol A-B (4-5), and garcinone F (6) along with twelve known compounds 7-18 were obtained from the latex of Garcinia cowa Roxb. ex Choisy. All new compounds have a 1,3,7-trioxygenated or 1,3,6,7-tetraoxygenated xanthone nucleus and differ from majority of xanthones from G. cowa by hydrated side chains. Compounds 1, 7, 8 and 18 exhibited significant neuroprotective effects on glutamate-mediated hippocampal neuronal HT22 cell death. In particular, compound 1 exhibited the most potent neuroprotective effect with >80 % cell viability in the concentration range of 2.9-115 µM. Further studies on compound 1 showed that it decreased cellular Ca2+ influx and inhibits cellular reactive oxygen species generation in HT22 cells. A Western blot analysis showed that MAPK phosphorylation, Bax, and AIF translocation dramatically increased upon treatment with 5 mM glutamate and decreased upon a co-treatment with compound 1.

Genome analysis of the heterotrophic microalga Thraustochytrium sp. TN22 to identify genes involved in exopolysaccharide and carotenoid biosynthesis pathways.

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 ß-carotene to xanthophyll proceeds through ß-cryptoxanthin and zeaxanthin intermediates. Our results will be useful for improving high-value coproducts for industrial application of thraustochytrids.

Correlation between the ankle-brachial index and microalbuminuria with certain risk factors in type 2 diabetes patients.

The ankle-brachial index (ABI) is a fast, simple, noninvasive method that provides accurate results in the early diagnosis of peripheral artery disease. Microalbuminuria is considered a predictor of renal and cardiovascular complications in patients with diabetes. This study was conducted to determine the correlation between ABI and microalbuminuria with certain risk factors in patients with type 2 diabetes. SUBJECTS AND RESEARCH METHODS: A cross-sectional descriptive study was performed on 62 inpatients with type 2 diabetes. All patients were measured for ABI as well as microalbuminuria, HbA1c, glucose and lipidemia in the blood. RESULTS: The study results showed that in patients with dyslipidemia, the risk of having microalbuminuria (+) increased 5.7 times and ABI ≤0.90 increased 8.6 times (P = 0.004 and 0.021, respectively). Fasting blood glucose >7.2 mmol/L had 5.7 times higher microalbuminuria (+) risk and 8.6 times higher ABI ≤0.90 (P = 0.004 and 0.021, respectively). Patients with HbA1c ≥7% were 2.9 times more likely to have microalbuminuria (+) and ABI ≤0.90 (P = 0.043 and 0.048, respectively). CONCLUSIONS: Peripheral vascular disease risk factors such as hypertension, dyslipidemia and waist circumference and the effectiveness of fasting blood glucose and HbA1c control increased the risk of high microalbuminuria and ABI in patients with type 2 diabetes.

Analysis of Outbreak and Global Impacts of the COVID-19.

Corona viruses are a large family of viruses that are not only restricted to causing illness in humans but also affect animals such as camels, cattle, cats, and bats, thus affecting a large group of living species. The outbreak of Corona virus in late December 2019 (also known as COVID-19) raised major concerns when the outbreak started getting tremendous. While the first case was discovered in Wuhan, China, it did not take long for the disease to travel across the globe and infect every continent (except Antarctica), killing thousands of people. Since it has become a global concern, different countries have been working toward the treatment and generation of vaccine, leading to different speculations. While some argue that the vaccine may only be a few weeks away, others believe that it may take some time to create the vaccine. Given the increasing number of deaths, the COVID-19 has caused havoc worldwide and is a matter of serious concern. Thus, there is a need to study how the disease has been propagating across continents by numbers as well as by regions. This study incorporates a detailed description of how the COVID-19 outbreak started in China and managed to spread across the globe rapidly. We take into account the COVID-19 outbreak cases (confirmed, recovered, death) in order to make some observations regarding the pandemic. Given the detailed description of the outbreak, this study would be beneficial to certain industries that may be affected by the outbreak in order to take timely precautionary measures in the future. Further, the study lists some industries that have witnessed the impact of the COVID-19 outbreak on a global scale.

Biocharacteristics and draft genome sequence of Halomonas hydrothermalis C22, a pyruvate-producing halophilic bacterium isolated from a commercial Spirulina culture in Vietnam.

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.

Preparation and Evaluation of Cream Mask from Vietnamese Seaweeds.

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 Caulerpa lentillifera, Sargassum crassifolium, Ulva reticulata, and Kappaphycus alvarezii are potential rich sources of protein, polysaccharide, carotenoids, and vitamins with high antibacterial, cell proliferation, moisture retention, and tyrosinase inhibitory activities. Physicochemical analysis of cream mask from a mixture of these seaweed extracts indicated that it is yellowish brown in color with a specific odor of seaweed, stable, and homogeneous for up to 12 months of storage, with a pH of 6.1, and high spread and adhesive abilities. No total aerobic mesophilic microorganisms, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and heavy metals were detected in the seaweed mask cream. The seaweed cream mask was safe and caused no irritation to normal human skin, and it satisfied provisions of Circular No. 06/2011/TT-BYT dated January 25, 2011 of the Vietnam Ministry of Health, providing cosmetic management for the cosmetic products with anti-aging and moisturizing effects.

Squalene promotes cholesterol homeostasis in macrophage and hepatocyte cells via activation of liver X receptor (LXR) α and ß.

OBJECTIVE: 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. RESULTS: 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 LXRß. 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. CONCLUSION: Squalene has hypocholesterolemic effect through the activation of LXRα and ß without inducing hepatic lipogenesis.

Indications for and techniques of keratoplasty at Vietnam National Institute of Ophthalmology.

AIM: To report the indications for and techniques of corneal transplantation at Vietnam National Institute of Ophthalmology (VNIO) over a period of 12y (2002-2013). METHODS: Records of patients who had undergone corneal transplantation at VNIO from January 1, 2002 to January 1, 2014 were reviewed to determine the indication for and type of corneal transplant performed. Patient age, gender, indication for corneal transplantation and surgical technique were recorded and analyzed. RESULTS: Corneal transplantation were underwent in 1390 eyes of 1278 patients with a mean age of 44.9±18.1y during the period under review. The most common indication was infectious corneal ulcer (n=670; 48.2%), followed by corneal scar (n=333, 24.0%), corneal dystrophy (n=138, 9.9%) and failed graft (n=112, 8.1%). Nearly all procedures performed were penetrating keratoplasty (n=1300, 93.5%), with a few lamellar keratoplasty procedures performed: lamellar keratoplasty (n=52, 3.7%), Descemet's stripping automated endothelial keratoplasty (n=27, 1.9%) and deep anterior lamellar keratoplasty (n=11, 0.8%). CONCLUSION: While the most common indication for keratoplasty was infectious keratitis, nearly all indications for corneal transplantation were managed with penetrating keratoplasty. However, lamellar keratoplasty techniques, including deep anterior lamellar keratoplasty and Descemet's stripping automated endothelial keratoplasty, are being performed with increasing frequency for isolated stromal and endothelial disorders, respectively.

Squalene isolated from Schizochytrium mangrovei is a peroxisome proliferator-activated receptor-α agonist that regulates lipid metabolism in HepG2 cells.

OBJECTIVE: Peroxisome proliferator-activated receptor-alpha (PPARα) is a nuclear receptor that has critical roles in the treatment of atherosclerosis, hyperlipidemia and hepatic steatosis. RESULTS: Squalene is a novel nature PPARα agonist, identified from reporter gene assay and qPCR analysis. Cultured hepatocytes stimulated with squalene exhibited significantly decreased cellular triacylglycerols and cholesterol concentrations, while cellular uptake of fatty acids was increased. Quantitative PCR analysis revealed that expression of genes related to fatty acid uptake, fatty acid oxidation, ketogenesis and reverse cholesterol transport metabolism were upregulated, while that of genes related to fatty acid synthesis were suppressed in cell treated with squalene. CONCLUSION: Squalene is hypolipidemic by activation of PPARα via a ligand-mediated mechanism that regulates the expression of lipid metabolism genes in hepatocytes.

Valorization of humin-based byproducts from biomass processing-a route to sustainable hydrogen.

The synthesis of biomass-based top value-added chemical platforms, for example, 5-hydroxymethyl furfural, furfural, or levulinic acid from the acid-catalyzed dehydration of sugars results in high yields of insoluble by-products, referred to as humin. Valorization of humin by steam reforming for H2 is discussed. Both thermal and catalytic steam gasification were investigated systematically. Humin undergoes drastic changes under thermal pre-treatment to the gasification temperature. Alkali-metal-based catalysts were screened for the reactions. Na2 CO3 showed the highest activity and was selected for further study. The presence of Na2 CO3 enhances the gasification rate drastically, and gas-product analysis shows that the selectivity to CO and CO2 is 75% and 25%, respectively, which is a H2 /CO ratio of 2 (corresponding to 81.3% H2 as compared to the thermodynamic equilibrium). A possible process for the complete, efficient conversion of humin is outlined.

Phylogenetic analyses of Prorocentrum spp. and Alexandrium spp. isolated from northern coast of Vietnam based on 18S rDNA sequence.

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.

Nutritional analysis of Vietnamese seaweeds for food and medicine.

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, vitamins, 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.