The proliferation and differentiation of pre-osteoblastic MC3T3-E1 cells from Vietnamese drug formulations

A public heath problem, osteoporosis, is recognized as the prevalent disease, and mainly causes for impairment and loss mass of bone. It closely related the balance between bone formation by osteoblasts and resorption by osteoclasts during the remodeling cycle of bone. Hence, pharmaceutical therapies are looking for the potential agents to stimulate osteoblastic bone formation, as well as inhibit osteoclastic processes

Optimization and Characterization of Paper-based SERS Substrates for Detection of Melamine

A flexible low-cost paper-based surface enhanced Raman scattering (SERS) substrate was successfully manufactured by a direct chemical reduction of silver nanoparticles (AgNPs) onto a common commercially available filter paper. Characterization of fabricated paper-based SERS substrate and the influences of the silver nitrate concentration, type of paper on SERS signal were systematically investigated. In order to fabricate SERS substrates with the highest quality, a suitable one from four different types of filter papers was chosen. The prepared SERS substrates have capability for detecting food toxic chemicals. The test of detecting melamine in aqueous solution was successfully demonstrated with the limit of detection for melamine is 10-7M

Characterization of Genetic Elements Carrying mcr-1 Gene in Escherichia coli from the Community and Hospital Settings in Vietnam

Colistin is widely used in agriculture and aquaculture as prophylaxis, particularly in Asia. Recently, mcr-1 and other mobilizable genes conferring colistin resistance have spread globally in community and hospital populations. Characterizing mcr-1 mobile genetic elements and host genetic background is important to understand the transmission of this resistance mechanism. We conducted whole-genome sequencing of 94 mcr-1-positive Escherichia coli isolates (Mcr1-Ec isolates) from human and animal feces, food, and water in a community cohort (N = 87) and from clinical specimens from a referral hospital (N = 7) in northern Vietnam. mcr-1 was plasmid-borne in 71 and chromosomally carried in 25 (2 isolates contain one copy on chromosome and one copy on a plasmid) of 94 E. coli isolates from the community and hospital settings. All seven clinical isolates carried mcr-1 on plasmids. Replicon types of mcr-1-carrying plasmids included IncI2, IncP, IncX4, and IncFIA single replicons and combinations of IncHI2, IncN, and IncX1 multireplicons. Alignment of a long-read sequence of an IncI2 plasmid from animal feces with short-read sequences of IncI2 plasmids from a healthy human, water, and hospitalized patients showed highly similar structures (query cover from 90% to 98%, overall identity of >81%). We detected the potential existence of multireplicon plasmids harboring mcr-1 regardless of sample setting, confirming 10/71 with long-read sequencing. An intact/conserved Tn6330 transposon sequence or its genetic context variants were found in 6/25 Mcr1-Ec isolates with chromosomally carried mcr-1. The dissemination of mcr-1 is facilitated by a high diversity of plasmid replicon types and a high prevalence of the chromosomal Tn6330 transposon. IMPORTANCE The article presented advances our understanding of genetic elements carrying mcr-1 in Escherichia coli in both community and hospital settings. We provide evidence to suggest that diverse plasmid types, including multireplicon plasmids, have facilitated the successful transmission of mcr-1 in different reservoirs. The widespread use of colistin in agriculture, where a high diversity of bacteria are exposed, has allowed the selection and evolution of various transmission mechanisms that will make it a challenge to get rid of. Colocalization of mcr-1 and other antibiotic resistance genes (ARGs) on multireplicon plasmids adds another layer of complexity to the rapid dissemination of mcr-1 genes among community and hospital bacterial populations and to the slow pandemic of antimicrobial resistance (AMR) in general