No abstract

In the world and Vietnam, a great number of toxic substances from industrial and agricultural activities, food production, and healthcare services are daily released into the environment. Many exogenous harmful substances are procarcinogens, but become carcinogens by the bioactivation of human cytochrome P450 enzymes (CYPs). Thus, development of analytical testing for rapid detection of procarcinogens plays a crucial role in food safety and environmental monitoring. This study aims to establish a biosensor basing on Saccharomyces cerevisiae Y486 cotransformed with two promoter–gene constructs, CYP3A4–CPR and DIN7–GFP. The results showed that all recombinant proteins were coexpressed in Y486 cells. The molecular weight of recombinant CPR and CYP3A4 were 75 kDa and 56 kDa, respectively. CYP3A4 enzyme only showed its catalytic activity in biotransformation of the specific substance as coexpressed with CPR. Kinetic constants, Km, Vmax, and Vmax/Km, of this CPR–CYP3A4 enzyme complex were 3.2 µM, 3.5 pmol/pmol CYP/min, and 1.1 μL/pmol CYP/min, respectively. Coexpressing constructs of CPR–CYP3A4 and DIN7-GFP in Y486 strain was able to identify aflatoxin B1 in the range of 0.1 - 0.4 µM; benzo(c)pyrene in the range of 10 - 40 µM. However, this system could not detect other procacinogens, such as, N-Nitrosodimethylamine, at any investigated concentrations. These findings were the first trial for further development of other biosensors to determine diverse procarcinogens in the enviroment by redesign of coexpressing constructs or replacement of the specific CYPs and inducible promoters.

Mesenchymal stem cells (MCSs) from adipose tissue are reported to have a pronounced impact on tumor growth or suppression. However, so far, how the cancer cells affect the stem cells in vivo conditions has not been clarified. In this study, we evaluated the impact of breast cancer cells on the characteristics of adipose-derived stem cells (ADSCs) under in vivo conditions. ADSCs were obtained from Balb/c mice in three consecutive weeks after transplantation with 1×106 MCF7 cells. The results showed that the amount of ADSCs per one gram fat reduced over time, but that reduction was not significantly different. In fact, isolated ADSCs presenting specific MSC surface markers increased at the second passage, compared to the time of isolation. Particularly, they were highly positive for CD90 (a MSC indicator) and negative for CD45 (a hematopoietic marker). Moreover, in in vitro culture, ADSCs were successfully differentiated into adipocytes, which were detected by Oil Red O staining. This present experiment gives initial assessments of ADSC characteristics; however, further investigations are necessary to fully evaluate the differences in stem cell potency and immunophenotype caused by cancer cell transplantation.

Recent advances in metagenomics and bioinformatics allow the robust analysis of the composition and abundance of microbial communities, functional genes, and their metabolic pathways. So far, there has been a variety of computational/statistical tools or software for analyzing microbiome, the common problems that occurred in its implementation are, however, the lack of synchronization and compatibility of output/input data formats between such software. To overcome these challenges, in this study context, we aim to apply the DADA2 pipeline (written in R programming language) instead of using a set of different bioinformatics tools to create our own workflow for microbial community analysis in a continuous and synchronous manner. For the first effort, we tried to investigate the composition and abundance of coral-associated bacteria using their 16S rRNA gene amplicon sequences. The workflow or framework includes the following steps: data processing, sequence clustering, taxonomic assignment, and data visualization. Moreover, we also like to catch readers’ attention to the information about bacterial communities living in the ocean as most marine microorganisms are unculturable, especially residing in coral reefs, namely, bacteria are associated with the coral Acropora tenuis in this case. The outcomes obtained in this study suggest that the DADA2 pipeline written in R programming language is one of the potential bioinformatics approaches in the context of microbiome analysis other than using various software. Besides, our modifications for the workflow execution help researchers to illustrate metagenomic data more easily and systematically, elucidate the composition, abundance, diversity, and relationship between microorganism communities as well as to develop other bioinformatic tools more effectively.

Coral reefs harbor the extraordinary biodiversity and not only provide livelihoods for coastal communities but also play a crucial role in economic development generally. Unfortunately, they are in decline in Vietnam and around the world because mass coral bleaching events have become more common worldwide. However, little is discovered, about viruses that infect corals and their symbionts. Herein, we present metagenomic analyses of the viral communities in coral mucus associated with healthy and bleached coral Acropora formosa which was collected at Con Dao Island, Vietnam. Interestingly, the number of viral species in bleached specimens are higher than those in healthy status. Viruses similar to those that infect humans and some marine animals also appeared in the coral viral assemblage. The results indicated that the proportion of shared viruses were quite small, and represented extremely abundance. Among the phage identified, vibriophage and cyanophage were only presented in healthy and bleached coral, respectively. Therefore, coral-associated viruses could prospectively infect all constituents of the holobiont - coral, microalgal and microbial. Thus, we expect viruses to be illustrated prominently in the preservation and breakdown of coral health.