Lipase activity in Thermus thermophilus HB8: Purification and characterization of the extracellular enzyme

Dual-factor Synergistically Activated ESIPT-based Probe: Differential Fluorescence Signals to Simultaneously Detect α-Naphthyl Acetate and Acid α-Naphthyl Acetate Esterase

α-Naphthyl acetate esterase (α-NAE) and acid α-naphthyl acetate esterase (ANAE), a class of special esterases, are important for lymphocyte typing and immunocompetence-monitoring. As such, the simultaneous detection of α-NAE and ANAE has become a target to effectively improve the accuracy in lymphocyte typing. Therefore, we developed a dual-factor synergistically activated ESIPT-based probe (HBT-NA) to detect α-NAE and ANAE sensitively, rapidly, and simultaneously in a differential manner. HBT-NA exhibits differential fluorescence signal outputs toward small changes of α-NAE and ANAE activities. HBT-NA displays a weak fluorescence signal at 392 nm over a pH range from 6.0 to 7.4. However, when it interacts with α-NAE (0-25 U) at pH = 7.4, the fluorescence intensity at 392 nm enhanced linearly within 60 s (F_392 nm/F0_392 nm = 0.042 C_α-NAE + 1.1, R² = 0.99). Furthermore, HBT-NA emits ratiometric fluorescence signals (F_505 nm/F_392 nm) for ANAE (0-25 U) at pH = 6.0 within 2.0 min, exhibiting a good linear relationship (F_505 nm/F_392 nm = 0.83C_ANAE - 1.75, R² = 0.99). The differential fluorescence signals can be used to simultaneously detect the activities of α-NAE and ANAE in solutions and complex living organisms. More importantly, based on the differential fluorescence signals toward α-NAE and ANAE, T lymphocytes and B lymphocytes could be successfully typed and differentiated among nontyped lymphocytes, facilitating the real-time evaluation of their immune functions using flow cytometry. Hence, HBT-NA could be used for the ultrasensitive detection of the enzyme activities of α-NAE and ANAE, the real-time precise typing of lymphocytes, and the monitoring of immunocompetence.

Novel thermostable lipase produced by a thermo-halophilic bacterium that catalyses hydrolytic and transesterification reactions

Lipase belongs to the class of hydrolytic enzymes that are widely used in the biotechnology industries. The goal of this research was to purify and characterize lipase produced from a thermo-halophilic bacterium, namely Pria Laot Sabang 80 (PLS 80). Purification was performed using ammonium sulphate fractionation, followed by gel filtration chromatography using Sepharose Cl-6B. After purification, the enzyme had a specific activity of 326.6 U/mg with a purity of 6.02 higher than the crude extract; with a molecular weight of around 50 kDa. The optimum activity was observed at 70 °C and pH 9. The activity increased in the presence of 10 mM Mn²⁺, K⁺ and Ca²⁺ ions, while Hg²⁺ only slightly increased the enzyme activity. In contrast, the activity decreased in 10 mM Mg²⁺, Zn²⁺, Co²⁺, EDTA, and PMSF. The enzyme showed good hydrolytic activity on long fatty acids substrates (p-nitrophenyl palmitate) with a value of 35.5 U/mL. It was also able to catalyze a transesterification reaction. GC-MS result showed that the biodiesel consisted of methyl octanoate (5.3%), methyl caprate (12.4%), methyl laurate (34.1%), methyl myristate (10.7%), methyl palmitate (3.9%), and methyl stearate (1.2%) when using coconut oil as the substrate. The results suggested that the lipase from PLS 80 had unique attributes that could be useful in various industrial applications.

Complete Genome Analysis of Thermus parvatiensis and Comparative Genomics of Thermus spp. Provide Insights into Genetic Variability and Evolution of Natural Competence as Strategic Survival Attributes

Thermophilic environments represent an interesting niche. Among thermophiles, the genus Thermus is among the most studied genera. In this study, we have sequenced the genome of Thermus parvatiensis strain RL, a thermophile isolated from Himalayan hot water springs (temperature >96°C) using PacBio RSII SMRT technique. The small genome (2.01 Mbp) comprises a chromosome (1.87 Mbp) and a plasmid (143 Kbp), designated in this study as pTP143. Annotation revealed a high number of repair genes, a squeezed genome but containing highly plastic plasmid with transposases, integrases, mobile elements and hypothetical proteins (44%). We performed a comparative genomic study of the group Thermus with an aim of analysing the phylogenetic relatedness as well as niche specific attributes prevalent among the group. We compared the reference genome RL with 16 Thermus genomes to assess their phylogenetic relationships based on 16S rRNA gene sequences, average nucleotide identity (ANI), conserved marker genes (31 and 400), pan genome and tetranucleotide frequency. The core genome of the analyzed genomes contained 1,177 core genes and many singleton genes were detected in individual genomes, reflecting a conserved core but adaptive pan repertoire. We demonstrated the presence of metagenomic islands (chromosome:5, plasmid:5) by recruiting raw metagenomic data (from the same niche) against the genomic replicons of T. parvatiensis. We also dissected the CRISPR loci wide all genomes and found widespread presence of this system across Thermus genomes. Additionally, we performed a comparative analysis of competence loci wide Thermus genomes and found evidence for recent horizontal acquisition of the locus and continued dispersal among members reflecting that natural competence is a beneficial survival trait among Thermus members and its acquisition depicts unending evolution in order to accomplish optimal fitness.