Based on a total of 6,295,650 sequences from the V3 and V4 regions (16S ribosomal RNA), the composition of the microorganism communities in the water of three Litopenaeus vannamei (Decapoda, Whiteleg shrimp; Soc Trang, Vietnam) ponds were identified. Pseudomonas (10–20.29%), Methylophilus (13.26–24.28%), and Flavobacterium (2.6–19.29%) were the most abundant genera. The total ammonia (TAN) concentration (p = 0.025) and temperature (p = 0.015) were significantly correlated with the relative abundance of Pseudomonas in two bacterial communities (ST1, ST4), whereas the predictive functions of microorganism communities based on 16S rRNA gene data was estimated using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUST), which showed that nitrogen metabolism was significantly negatively correlated (p = 0.049) with TAN concentration. The abundance of Pseudomonas and nitrogen metabolism increased with a decrease in TAN concentration. The correlation between TAN concentration and the abundance of Pseudomonas was followed by the isolation, and heterotrophic nitrifying performance analysis was used to confirm our findings. Six Pseudomonas strains capable of heterotrophic nitrification were isolated from the three water samples and showed a complete reduction of 100 mg/L NH₄Cl during a 96-h cultivation. These results indicate the potential of applying Pseudomonas in shrimp ponds for water treatment.

Nitrogen compounds, especially ammonia, are widely produced in aquaculture systems during cultivation. Ammonia has been investigated as a model compound for use by heterotrophic nitrifying bacteria. Pseudomonas TT321 and Pseudomonas TT322, isolated from shrimp pond water in Soc Trang province, Vietnam, are identified by comparing them with 31 of the closest genomes sequences from the NCBI nucleotide database. The genome sizes of strains TT321 and TT322 were 5,566,241 bp and 5,563,644 bp, respectively. No plasmids were evident in these strains. Genome analysis revealed that TT321 and TT322 belonged to Pseudomonas putida and shared a common ancestor with 33 genomes. Analysis based on the comparison of genomes showed that three genes, carbamate kinase (arcC), glutamine synthetase (Glul), and aminomethyltransferase (amt), are involved in three metabolic pathways. These pathways are: (i) arginine and proline metabolism, (ii) alanine, aspartate and glutamate metabolism, and (iii) glycine, serine and threonine metabolism. These genes may play important roles in ammonia reduction and support bacterial growth via ammonia assimilation.

Umbilical cord hematopoietic stem cells (UC-HSCs) are capable of self-regeneration and differentiation into many different types of blood cells, helping to treat blood diseases such as leukemia, Hodgkin's disease and non-Hodgkin's lymphoma, as well as for transplantation. However, the number of UC-HSCs is still very small due to limitations in isolation and proliferation. In this study, UC-HSCs were cultured with the bioactive SL-13R peptide to examine whether SL-13R enhances UC-HSC proliferation. Here, we showed that CD34+UC-HSCs can be enriched by up to 47.08% by culturing total mononuclear cells (MNCs) from umbilical cord blood (UCB) in serum-free StemMACS medium supplemented with a cytokine cocktail. We demonstrated that SL-13R enhanced the proliferation of CD34+UC-HSCs by 1.21-1.44 times compared to that of the controls. These results suggested that StemMACS medium supplemented with cytokines and SL-13R can be used to expand CD34+UC-HSCs ex vivo for medical treatment and transplantation.

There are three groups of potential stem cells that are widely used in regenerative medicine in clinical practice: hematopoietic stem cells, mesenchymal stem cells, and epithelial stem cells. Among them, adipose-derived mesenchymal stem cells (ASCs) are very common in the human body and can be easily obtained without causing major damage to the body. The use of human adipose-derived stromal vascular fraction (SVF) therapy has increased in recent years. SVF is a rich source of mesenchymal stem cells (MSCs) used in regenerative medicine. This study evaluated the effect of collagenase incubation time on the efficiency of SVF isolation and MSC viability. The aim of the study was to optimize the SVF isolation time to obtain MSCs with a high survival rate in clinical applications while ensuring the stemness and differentiation ability of MSCs after isolation. Collagenase digestion at different time points (60, 120, and 180 minutes) was compared, measuring MSC yield and viability via flow cytometry and differentiation assays. Results indicated that 120 minutes of collagenase treatment provided optimal MSC yield and cell viability, demonstrating significant differentiation potential, making this time point ideal for clinical applications.

Gut bacteria comprise a complex bacterial community related to many functions in a host. The stability of gut bacteria plays important models in the health and immunology of a host. Many studies on intestine bacteria constructed via cultivation and Denaturation Gradient Gel Electrophoresis (DDGE) methods have proved a limited efficiency. In order to tackle these drawbacks, the next generation sequencing method was developed on 16S-rRNA-based sequences (Metabarcoding). The composition of bacterial communities was revealed based on the analysis of 16S rRNA sequences of intestine bacteria in Litopenaeus vannamei ponds in comparison with microbial communities in a Penaeus monodon pond and a muscle of shrimp. These results showed that the dominant phyla of intestine bacteria in Litopenaeus vannamei were Proteobacteria (49.3–57.4%), Firmicutes (15.6–34.4%) and Bacteroidetes (0.1–16.9%). Rhizobium(0.4%-26.1%), Vibrio(0–23.9%) and Spongiimonas(0–16,7%) were dominant genera in Litopenaeus vannamei gut. A higher proportion of Fusobacterium (10%), a shrimp pathogen group, was found in a disease shrimp pond (ST4) in comparison with a low growth shrimp pond (ST3) (0%) and a healthy shrimp pond (ST1) (0.6%). Vibrio was marked as shrimp pathogen genus accounted for 22.3% of total genera in ST4 in comparison with 2.4% in ST3 and 3.5% in ST1. Interestingly, a higher percentage of Vibrio rotiferianus (7.98%) was found in ST4 compared to ST3 (1%) and ST1 (0%). Fusobacterium and Vibrio will be the objects for the next experiments to discover shrimp pathogens specifically.