Effect of Hyperbaric Pressure on Pseudomonas aeruginosa Isolated from Divers with Otitis Externa

Kevin Maclean^* and Ezekiel Green

University of Johannesburg, South Africa

P seudomonas aeruginosa (P. aeruginosa) is an important opportunistic pathogen associated with swimmerʼs ear infections (otitis externa) in professional divers at Sodwana Bay, KwaZulu Natal, South Africa. This bacterium is known for its serious worldwide emerging antimicrobial resistance. Previous studies mainly focused on the use of hyperbaric conditions as an adjunctive therapy to antimicrobials for such infections. However, there are only a few studies describing the effect of hyperbaric conditions on the molecular characteristics of P. aeruginosa and none for isolates from professional divers with otitis externa at Sodwana Bay. The present study tested the effect of pressure on selected P. aeruginosa previously isolated from divers with otitis externa and their diving environment at Sodwana Bay. With this study, we developed a method that enables the activity of pressure on P. aeruginosa to be measured using mutations on the gene sequences. However, during the onset of this study it was found that the chamber was severely contaminated with other bacteria which could interfere with the integrity of our results. This required an intervention to avoid bacterial contamination of microbial experiments in hyperbaric chambers. The existing membrane filtration apparatus typically used for the quantification of bacteria in water was modified to prevent contamination of hyperbaric microbiology experiments. This resulted in the novel development of an “Aseptic Millipore Membrane Filtration Hyperbaric Recompression of Bacterial Isolates in Microbiological Experiments” technique. It is an improvement on current approaches as it will inhibit P. aeruginosa contamination from diving equipment while focusing on the organism to be investigated.

Biography:
Kevin Maclean is an employed academic at the University of Johannesburg teaching Microbiology to Biotechnologystudents. He is ferventto upgrade his qualification and is therefore currently busy finalizing a Doctorate in Biotechnology to be completed in 2020. At leisure he is a SCUBA diving instructor whotrainsindividuals to become safe divers. He wedded his passion for diving with the academia and embarked on a research project which overall investigate ear infection in SCUBA divers. A part of this study included the development of a method to prevent bacterial contamination in a hyperbaric chamber occasionally used for microbiological experiments.

Regulation of Mg⁺²-Dependent Phosphatidic Acid Phosphatase Enzymes in the Yeast Yarrowia lipolytica

Pasham S, Adebayo T and Fakas S

Alabama A&M University, USA

Single-cell oils (SCOs) are considered major products capable of producing polyunsaturated fatty acids (PUFAs) that are essential for human nutrition. They are derived from microorganisms such as Yarrowia lipolytica. In this yeast, during the lipid biosynthesis,phosphatidic acid phosphatase (PAP) catalyzes the conversionof diacylglycerol (DAG) to triacylglycerol (TAG) in a reaction that depends on Mg⁺². In Y. lipolytica, the PAH1 and APP1 genes encode for Mg⁺²-dependent PAP activity, but their regulation has not been studied in detail. In this work, we constructed a strain that lacks both PAH1 and APP1 (i.e., pah1Δapp1Δ) to examine the contribution of these enzymes to PAP activity and TAG biosynthesis. We grew the strains in high glucose media that favors the lipid accumulation and measured the PAP enzymatic activity during lipogenesis. The contribution of the genes was examined by comparing the PAP activity and lipid profiles between a wild type strain, a mutant strain that lacks PAH1 (i.e., pah1Δ), and a mutant strain that lacks both PAH1 and APP1 (i.e., pah1Δapp1Δ). The results showed that 90% of the Mg⁺²-dependent PAP activity is encoded by the PAH1 gene, while APP1 is only contributing 10% of that activity.Next, we examined the role that these enzymes play in TAG biosynthesis. The lack of PAH1alone (i.e., pah1Δ) resulted in a 20% reduction of the TAG levels, while the lack of APP1 did not have a significant effect on TAG levels. These results showed that APP1 does not contribute to TAG biosynthesis in Y. lipolytica.

Keywords: Single-cell oils, PUFAs, Triacylglycerols, Phosphatidic acid phosphatase, High glucose, PAP activity, Lipid profile, Yarrowia. lipolytica.

A Facile Method for Tracking Hepatocytes Transplantation

Xin Pan¹, Siliang Zeng², Fengfeng Lu¹, Changcheng Liu¹, Zhongmin Liu¹ and Zhiying He¹

¹Institute for Regenerative Medicine, Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, P.R. China
²Rehabilitation Therapy Department, School of Health, Shanghai Normal University Tianhua College, P.R. China

Cell transplantation therapy has been broadly used to cure the diseases requiring tissue repairments or replacements. Usually, a preclinical method to systematically evaluate the dynamic change of donor cells in recipients, is highly needed to judge the potential therapeutic effect for the particularly designed cell transplantation. For this purpose, three-dimensional (3D) optical imaging was used to track dynamic cell for evaluating the transplanted hepatocytes in a mouse model of liver failure. This protocol directed to precisely evaluate the dynamic movements of donor hepatocytes, which was helpful for judging the capacities of cell candidates before their clinical application.

Keyword: Cell transplantation, in vivo tracking, bioluminescence imaging

Acknowledgements:
This work was supported by NationalKeyResearchandDevelopmentProject (ContractNo. 2020YFA0112604), National NaturalScience Foundation of China Grants (ContractNo. 30972633), the Shanghai Health and Family Planning Commission Project (ContractNo. 201640253).