SECONDARY METABOLITES FROM A MARINE-DERIVED FUNGUS Penicillium chrysogenum 045-357-2

Marine fungi represent a potential source for natural products in the future due to the incredible diversity of chemical compounds. In our previous investigation to search new antimicrobial agents from marine-derived fungi, we isolated fungal strain Penicillium chrysogenum 045-357-2 from a soft coral sample collected from Ca Na Bay, Ninh Thuan, Vietnam. The fungus showed high antibacterial activity and was selected for further study. By various chromatography separations, two compounds including andrastinA (1) and citreohybridonol (2) were obtained from the ethyl acetate extract of culture medium of this strain. Their chemical structures were determined by analysis of 1D and 2D NMR spectra and high-resolution mass spectroscopic data, as well as by comparison of the corresponding data to those previously reported in the literature. The compound 2 exhibited antibacterial activity towards Bacillus cereus ATCC 11778 and Streptoccocus faecalis ATCC 19433 with Minimal Inhibitory Concentration (MIC) values of 32 and 64 μg/ml, respectively; however, antibacterial activity was not detected in the compound 1. This is the first report on these compounds of marine fungal strain P. chrysogenum isolated in Vietnam

Isolation and screening marine fungi with antimicrobial activity from samples collected in Nha Trang bay, VietNam

The marine environment is an extremely complex ecosystem and contains a broad spectrum of fungal diversity. Marine fungi have been shown to be tremendous sources for new and biologically active secondary metabolites. The present study aims to isolate and screen antimicrobial properties of 100 fungus strains from different marine sources including seaweeds, soft corals, sponges and sediment collected at Nha Trang Bay, Vietnam. In preliminary experiments, the crude extracts of these fungal isolates with ethyl acetate were screened for their antimicrobial activity against the human microbial pathogens including Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Listeria monocytogenes ATCC 19111, Streptococcus faecalis ATCC 19433 and Candida albicans ATCC 10231 by the disc diffusion method. Among the 100 isolates, 59 strains exhibited antimicrobial activity against at least two tested pathogens, that 57% against S. aureus, 50% against L. monocytogenes, 49% against B. cereus, 45% against S. faecalis, 7% against E. coli, 5% against C. albicans, and only 2% against P. aeruginosa. The present study has revealed the presence of high numbers of marine fungi from Nha Trang waters having antimicrobial properties and they need to be investigated further for natural bioactive products

Effect of cultural conditions on antimicrobial activity of marine-derived fungus Penicillium chrysogenum

Marine fungi are a potential source of structurally diversified bioactive secondary metabolites that are not found in terrestrial sources. In our continuous investigation to search new antimicrobial agents from marine-derived fungi, we isolated fungal strain 045-357-2 from a soft coral sample collected from Ca Na bay, Ninh Thuan, Vietnam. The strain showed high antibacterial activity and was selected for further study. According to Internal Transcribed Spacer (ITS) rDNA molecular methods, the fungus was identified as Penicillium chrysogenum 045-357-2 and had a 100% homology (600/600 bp) with a GenBank sequence from a reference P. chrysogenum strain (NCBI accession no. EF200090). In the present investigation, the fungus was studied on effect of different culture incubation period, pH and salinity for antimicrobial activity against pathogenic microbes including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Streptococcus faecalis, Listeria monocytogenes, and Candida albicans. The ethyl acetate extracts of culture medium of the fungal isolate were determined antimicrobial activity by disc diffusion assay. The results showed that the optimum antimicrobial activity of the fungal strain P. chrysogenum 045-357-2 was obtained in medium containing 20 g rice, 20 mg yeast extract, 10 mg KH2PO4 , and 40 mL natural seawater at 30oC on the 14th day of incubation. The strain also exhibited highest antimicrobial activity in the medium at initial pH 6.0 – 8.0 and salinity of 35 g/L. The findings indicate that cultural conditions significantly influenced on antimicrobial activity of the studied fungus. The optimization is potential use for further study on the mass cultivation and isolation of bioactive compounds for this fungus

HAEMAGGLUTINATION ACTIVITY OF THE EXTRACTS FROM SOME VIETNAM MARINE INVERTEBRATES

Aqueous extracts from 21 species of Vietnam marine invertebrates, including 11 bivalve and 10 gastropod species, were examined for haemagglutination activity using native and enzyme-treated different animal and human erythrocytes. The 8 bivalve and 10 gastropod species were found to have haemagglutinination activities toward at least one type of erythrocyte tested. A total of 86% of marine invertebrate species surveyed were active. Strong activity was detected in extracts from two bivalve species (Tridacna squamosa and Geloina coaxans) and three gastropod species (Tutufa rubeta, Pleuroploca trapezium and Tectus conus) with enzyme-treated rabbit, horse and human A, B, O erythrocytes. In a haemagglutination–inhibition test with various monosaccharides and glycoproteins, haemagglutination activities of two extracts from T. rubeta and P. trapezium had no affinity for any of the monosaccharides and glycoproteins tested, while activities of the extracts from T. squamosa and T. conus were strongly inhibited by porcine stomach mucin tested, suggesting the presence of lectins specific for O-glycans of these species. The activities of four marine invertebrate extracts were stable over a wide range ofpH and temperature. The haemagglutination activities of T. rubeta and P. trapezium extracts were independent of the presence of divalent cations, whereas the haemagglutination activity of extracts from T. squamosa and T. conus were slightly dependent on the presence of divalent cations. The results suggest that Vietnam marine invertebrates may be good sources of useful lectins for biochemical and biomedical applications

EFFECT OF CULTURE CONDITIONS FOR ANTIMICROBIAL ACTIVITY OF MARINE - DERIVED FUNGUS ASPERGILLUS FLOCCULOSUS 01NT.1.1.5

The biosynthesis of compounds with antibiotic activity produced by marine fungi, strongly depends on their growth conditions. A good understanding of the role of culture conditions in the biosynthesis of metabolites may lead to better exploitation of microbial metabolites. In this study, the influence of culture conditions including incubation period, initial pH and salinity on antimicrobial activity and secondary metabolites production of marine fungus 01NT.1.1.5 was investigated. This isolate, obtained from sponge Stylissa sp. in Nha Trang Bay, exhibited a broad spectrum of in vitro antimicrobial activity to Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 19111, Streptococcus faecalis ATCC 19433 and Candida albicans ATCC 10231. According to morphological characteristics and sequence analysis of 28S rDNA, the fungus was identified as Aspergillus flocculosus. The results indicated that antimicrobial activity and metabolite amount were highest when the fungus was cultivated in rice medium with incubation period of 20 days. The optimum salinity of 35 g/L and initial pH of 6.0 were found for the maximum antibiotic production. The colony growth, antimicrobial activity and production of secondary metabolites of the strain A. flocculosus 01NT.1.1.5 varied depending on salt concentrations and initial pH of medium. Particularly, extract of this fungus only showed activity against C. albicans when it was cultured in medium with 30-35 g/L salinity and initial pH 4.0-8.0. The results  indicate that salinity and initial pH along with cultivation period are important factors influencing antimicrobial activity and secondary metabolites of A. flocculosus 01NT.1.1.5, and might be for other marine fungi

Acceptance and user experiences of a wearable device for the management of hospitalized patients in COVID-19–designated wards in Ho Chi Minh City, Vietnam: action learning project

Background: Wearable devices have been used extensively both inside and outside of the hospital setting. During the COVID-19 pandemic, in some contexts, there was an increased need to remotely monitor pulse and saturated oxygen for patients due to the lack of staff and bedside monitors. Objective: A prototype of a remote monitoring system using wearable pulse oximeter devices was implemented at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam, from August to December 2021. The aim of this work was to support the ongoing implementation of the remote monitoring system. Methods: We used an action learning approach with rapid pragmatic methods, including informal discussions and observations as well as a feedback survey form designed based on the technology acceptance model to assess the use and acceptability of the system. Based on these results, we facilitated a meeting using user-centered design principles to explore user needs and ideas about its development in more detail. Results: In total, 21 users filled in the feedback form. The mean technology acceptance model scores ranged from 3.5 (for perceived ease of use) to 4.4 (for attitude) with behavioral intention (3.8) and perceived usefulness (4.2) scoring in between. Those working as nurses scored higher on perceived usefulness, attitude, and behavioral intention than did physicians. Based on informal discussions, we realized there was a mismatch between how we (ie, the research team) and the ward teams perceived the use and wider purpose of the technology. Conclusions: Designing and implementing the devices to be more nurse-centric from their introduction could have helped to increase their efficiency and use during the complex pandemic period

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Cytoprotective Polyketides from Sponge-Derived Fungus Lopadostoma pouzarii

The new polyketides lopouzanones A and B, as well as the new 1-O-acetyl and 2-O-acetyl derivatives of dendrodochol B, were isolated from the sponge-derived marine fungus Lopadostoma pouzarii strain 168CLC-57.3. Moreover, six known polyketides, gliorosein, balticolid, dendrodolide G, dihydroisocoumarine, (&ndash;)-5-methylmellein, and dendrodochol B, were identified. The structures of the isolated compounds were determined by a combination of NMR and ESIMS techniques. The absolute configurations of the lopouzanones A and B were determined using the Mosher&rsquo;s method. The cytotoxicity of the isolated compounds against human prostate cancer cells PC-3 and normal rat cardiomyocytes H9c2 was investigated. Gliorosein showed weak DPPH radical-scavenging activity and in vitro cardioprotective effects toward rotenone toxicity and CoCl2-mimic hypoxia