Purification and Characterization of Trehalase from Artemia Embryos and Larvae

Efficient production and characterization of a newly identified trehalase for inhibiting the formation of bacterial biofilms

Trehalase has attracted widespread attention in medicine, agriculture, food, and ethanol industry due to its ability to specifically degrade trehalose. Efficient expression of trehalase remains a challenge. In this study, a putative trehalase-encoding gene (Tre-zm) from Zunongwangia mangrovi was explored using gene-mining strategy and heterologously expressed in E. coli. Trehalase activity reached 3374 U·mL-1 after fermentation optimization. The scale-up fermentation in a 15 L fermenter was achieved with a trehalase production of 15,068 U·mL-1. The recombinant trehalase TreZM was purified and characterized. It displayed optimal activity at 35 °C and pH 8.5, with Mn2+, Sn2+, Na+, and Fe2+ promoting the activity. Notably, TreZM showed significant inhibition effect on biofilm forming of Staphylococcus epidermidis. The combination of TreZM with a low concentration of antibiotics could inhibit 70 % biofilm formation of Staphylococcus epidermidis and 28 % of Pseudomonas aeruginosa. Hence, this study provides a promising candidate for industrial production of trehalase and highlights its potential application to control harmful biofilms.

Purification and Characterization of Trehalase From Acyrthosiphon pisum, a Target for Pest Control

Insect trehalases are glycoside hydrolases essential for trehalose metabolism and stress resistance. We here report the extraction and purification of Acyrthosiphon pisum soluble trehalase (ApTreh-1), its biochemical and structural characterization, as well as the determination of its kinetic properties. The protein has been purified by ammonium sulphate precipitation, first followed by an anion-exchange and then by an affinity chromatography. The SDS-PAGE shows a main band at 70 kDa containing two isoforms of ApTreh-1 (X1 and X2), identified by mass spectrometry and slightly contrasting in the C-terminal region. A phylogenetic tree, a multiple sequence alignment, as well as a modelled 3D-structure were constructed and they all reveal the ApTreh-1 similarity to other insect trehalases, i.e. the two signature motifs ¹⁷⁹PGGRFRELYYWDTY¹⁹² and ⁴⁷⁹QWDFPNAWPP⁴⁸⁹, a glycine-rich region ⁵⁴⁹GGGGEY⁵⁵⁴, and the catalytic residues Asp336 and Glu538. The optimum enzyme activity occurs at 45 °C and pH 5.0, with K_m and V_max values of ~ 71 mM and ~ 126 µmol/min/mg, respectively. The present structural and functional characterization of soluble A. pisum trehalase enters the development of new strategies to control the aphids pest without significant risk for non-target organisms and human health.

Stress tolerance during diapause and quiescence of the brine shrimp, Artemia

Oviparously developing embryos of the brine shrimp, Artemia, arrest at gastrulation and are released from females as cysts before entering diapause, a state of dormancy and stress tolerance. Diapause is terminated by an external signal, and growth resumes if conditions are permissible. However, if circumstances are unfavorable, cysts enter quiescence, a dormant stage that continues as long as adverse conditions persist. Artemia embryos in diapause and quiescence are remarkably resistant to environmental and physiological stressors, withstanding desiccation, cold, heat, oxidation, ultraviolet radiation, and years of anoxia at ambient temperature when fully hydrated. Cysts have adapted to stress in several ways; they are surrounded by a rigid cell wall impermeable to most chemical compounds and which functions as a shield against ultraviolet radiation. Artemia cysts contain large amounts of trehalose, a non-reducing sugar thought to preserve membranes and proteins during desiccation by replacing water molecules and/or contributing to vitrification. Late embryogenesis abundant proteins similar to those in seeds and other anhydrobiotic organisms are found in cysts, and they safeguard cell organelles and proteins during desiccation. Artemia cysts contain abundant amounts of p26, a small heat shock protein, and artemin, a ferritin homologue, both ATP-independent molecular chaperones important in stress tolerance. The evidence provided in this review supports the conclusion that it is the interplay of these protective elements that make Artemia one of the most stress tolerant of all metazoan organisms.

Regulation of trehalase expression inhibits apoptosis in diapause cysts of Artemia

Trehalase, which specifically hydrolyses trehalose into glucose, plays an important role in the metabolism of trehalose. Large amounts of trehalose are stored in the diapause encysted embryos (cysts) of Artemia, which are not only vital to their extraordinary stress resistance, but also provide a source of energy for development after diapause is terminated. In the present study, a mechanism for the transcriptional regulation of trehalase was described in Artemia parthenogenetica. A trehalase-associated protein (ArTAP) was identified in Artemia-producing diapause cysts. ArTAP was found to be expressed only in diapause-destined embryos. Further analyses revealed that ArTAP can bind to a specific intronic segment of a trehalase gene. Knockdown of ArTAP by RNAi resulted in the release of cysts with coarse shells in which two chitin-binding proteins were missing. Western blotting showed that the level of trehalase was increased and apoptosis was induced in these ArTAP-knockdown cysts compared with controls. Taken together, these results show that ArTAP is a key regulator of trehalase expression which, in turn, plays an important role in trehalose metabolism during the formation of diapause cysts.

Purification and partial biochemical-genetic characterization of trehalose 6-phosphate synthase from muscles of adult female Ascaris suum

Trehalose 6-phosphate (T6P) synthase (TPS; EC 2.4.1.15) was isolated from muscles of Ascaris suum by ammonium sulphate fractionation, ion-exchange DEAE SEPHACEL(TM) anion exchanger column chromatography and Sepharose 6B gel filtration. On sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), 265-fold purified TPS exhibited a molecular weight of 66 kDa. The optimum pH and temperature of the purified enzyme were 3.8-4.2 and 35°C, respectively. The isoelectric point (pI) of TPS was pH 5.4. The studied TPS was not absolutely substrate specific. Besides glucose 6-phosphate, the enzyme was able to use fructose 6-phosphate as an acceptor of glucose. TPS was activated by 10 mM MgCl2, 10 mM CaCl2 and 10 mM NaCl. In addition, it was inhibited by ethylenediaminetetra-acetic acid (EDTA), KCl, FeCl3 and ZnCl2. Two genes encoding TPS were isolated and sequenced from muscles of the parasite. Complete coding sequences for tps1 (JF412033.2) and tps2 (JF412034.2) were 3917 bp and 3976 bp, respectively. Translation products (AEX60788.1 and AEX60787.1) showed expression to the glucosyltransferase-GTB-type superfamily.

Purification and characterization of acid trehalase from muscle of Ascaris suum (Nematoda)

Acid trehalase (EC 3.2.1.28) was isolated from muscle of Ascaris suum by fractionating with ammonium sulfate, acetone and column chromatography on DEAE-cellulose and phenyl sepharose CL-4B. The purified homogeneous preparation of native acid trehalase exhibited a molecular mass of 76 kDa and of 38 kDa on SDS-PAGE. The enzyme has the optimum pH 4.9, pI 4.3, Km of 6.6 mM and Vmax=34.5 nM min(-1) x mg(-1). Besides trehalose, it hydrolyses sucrose, isomaltose and maltose and, to a lesser degree melezitose, and it does not act on cellobiose and lactose. Acid trehalase was activated by MgCl2, KNO3, NaCl, CaCl2, CH2ICOOH and p-chloromercuribenzoate and inhibited by EDTA, ZnSO4 and FeCl3.