Sweet taste receptors play roles in artificial sweetener-induced enhanced urine output in mice.

Sweet taste receptors found in oral and extra oral tissues play important roles in the regulation of many physiological functions. Studies have shown that urine volume increases during the lifetime exposure to artificial sweeteners. However, the detailed molecular mechanism and the general effects of different artificial sweeteners exposure on urine volume remain unclear.

Study on the production of high 3HV content PHBV an open fermentation with waste silkworm excrement as the carbon source by the haloarchaeon .

Silkworm excrement is hard to be degraded or bio-utilized by environmental microorganisms due to its high content of heavy metals and antimicrobial biomacromolecules in mulberry leaves. In traditional Chinese silk industry, the silkworm excrement results in environmental problems. In this study, the silkworm excrement after chlorophyll ethanol-extraction was researched.

Production of Polyhydroxyalkanoates in Unsterilized Hyper-Saline Medium by Halophiles Using Waste Silkworm Excrement as Carbon Source.

The chlorophyll ethanol-extracted silkworm excrement was hardly biologically reused or fermented by most microorganisms. However, partial extremely environmental halophiles were reported to be able to utilize a variety of inexpensive carbon sources to accumulate polyhydroxyalkanoates. In this study, by using the nile red staining and gas chromatography assays, two endogenous haloarchaea strains: A85 and A112 of silkworm excrement were shown to accumulate poly(3-hydroxybutyrate) up to 0.

Enoyl-CoA hydratase mediates polyhydroxyalkanoate mobilization in Haloferax mediterranei.

Although polyhydroxyalkanoate (PHA) accumulation and mobilization are one of the most general mechanisms for haloarchaea to adapt to the hypersaline environments with changeable carbon sources, the PHA mobilization pathways are still not clear for any haloarchaea. In this study, the functions of five putative (R)-specific enoyl-CoA hydratases (R-ECHs) in Haloferax mediterranei, named PhaJ1 to PhaJ5, respectively, were thoroughly investigated. Through gene deletion and complementation, we demonstrated that only certain of these ECHs had a slight contribution to poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biosynthesis.

Activation of a dormant replication origin is essential for Haloferax mediterranei lacking the primary origins.

The use of multiple origins for chromosome replication has been demonstrated in archaea. Similar to the dormant origins in eukaryotes, some potential origins in archaea appear to be inactive during genome replication. We have comprehensively explored the origin utilization in Haloferax mediterranei.

A patatin-like protein associated with the polyhydroxyalkanoate (PHA) granules of Haloferax mediterranei acts as an efficient depolymerase in the degradation of native PHA.

The key enzymes and pathways involved in polyhydroxyalkanoate (PHA) biosynthesis in haloarchaea have been identified in recent years, but the haloarchaeal enzymes for PHA degradation remain unknown. In this study, a patatin-like PHA depolymerase, PhaZh1, was determined to be located on the PHA granules in the haloarchaeon Haloferax mediterranei. PhaZh1 hydrolyzed the native PHA (nPHA) [including native polyhydroxybutyrate (nPHB) and native poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (nPHBV) in this study] granules in vitro with 3-hydroxybutyrate (3HB) monomer as the primary product.

[Development of PhaP-tagged protein expression and purification systems for extremely halophilic archaea ].

[ OBJECTIVE] To establish a convenient halophilic protein expression and purification system based on the haloarchaeal-type PhaP and polyhydroxyalkanoate (PHA) granule. [METHODS] We cloned a strong haloarchaeal promoter and the phaP-tag into the haloarchaea- Escherichia coli shuttle vector pWL502, and then used the constructed vector to express the PhaP-tagged haloarchaeal proteins in the phaP-deleted strain Haloferax mediterranei AphaP. We purified the PhaP-fusion proteins, which were associated with PHA granules, by sucrose density gradient centrifugation.

A novel DNA-binding protein, PhaR, plays a central role in the regulation of polyhydroxyalkanoate accumulation and granule formation in the haloarchaeon Haloferax mediterranei.

Polyhydroxyalkanoates (PHAs) are synthesized and assembled as PHA granules that undergo well-regulated formation in many microorganisms. However, this regulation remains unclear in haloarchaea. In this study, we identified a PHA granule-associated regulator (PhaR) that negatively regulates the expression of both its own gene and the granule structural gene phaP in the same operon (phaRP) in Haloferax mediterranei.

Analysis of the transcriptional regulator GlpR, promoter elements, and posttranscriptional processing involved in fructose-induced activation of the phosphoenolpyruvate-dependent sugar phosphotransferase system in Haloferax mediterranei.

Among all known archaeal strains, the phosphoenolpyruvate-dependent phosphotransferase system (PTS) for fructose utilization is used primarily by haloarchaea, which thrive in hypersaline environments, whereas the molecular details of the regulation of the archaeal PTS under fructose induction remain unclear. In this study, we present a comprehensive examination of the regulatory mechanism of the fructose PTS in the haloarchaeon Haloferax mediterranei. With gene knockout and complementation, microarray analysis, and chromatin immunoprecipitation-quantitative PCR (ChIP-qPCR), we revealed that GlpR is the indispensable activator, which specifically binds to the PTS promoter (PPTS) during fructose induction.

Multiple propionyl coenzyme A-supplying pathways for production of the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in Haloferax mediterranei.

Haloferax mediterranei is able to accumulate the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with more than 10 mol% 3-hydroxyvalerate (3HV) from unrelated carbon sources. However, the pathways that produce propionyl coenzyme A (propionyl-CoA), an important precursor of 3HV monomer, have not yet been determined. Bioinformatic analysis of H.

Proteome reference map of Haloarcula hispanica and comparative proteomic and transcriptomic analysis of polyhydroxyalkanoate biosynthesis under genetic and environmental perturbations.

Many haloarchaea are known as polyhydroxyalkanoates (PHAs) producers, but a global and integrated view of the PHA biosynthesis is still lacking in this group of archaea. In this study, a combined proteomic and transcriptomic approach was employed in Haloarcula hispanica, a model haloarchaeon that accumulates poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) under nutrient-limiting conditions with excess carbon source. First, a comprehensive proteome reference map was established for H.

Cellular and organellar membrane-associated proteins in haloarchaea: perspectives on the physiological significance and biotechnological applications.

Halophilic archaea (haloarchaea) inhabit hypersaline environments, tolerating extreme salinity, low oxygen and nutrient availability, and in some cases, high pH (soda lakes) and irradiation (saltern ponds). Membrane-associated proteins of haloarchaea, such as surface layer (S-layer) proteins, transporters, retinal proteins, and internal organellar membrane proteins including intracellular gas vesicle proteins and those associated with polyhydroxyalkanoate (PHA) granules, contribute greatly to their environmental adaptations. This review focuses on these haloarchaeal cellular and organellar membrane-associated proteins, and provides insight into their physiological significance and biotechnological potential.

Identification of the haloarchaeal phasin (PhaP) that functions in polyhydroxyalkanoate accumulation and granule formation in Haloferax mediterranei.

The polyhydroxyalkanoate (PHA) granule-associated proteins (PGAPs) are important for PHA synthesis and granule formation, but currently little is known about the haloarchaeal PGAPs. This study focused on the identification and functional analysis of the PGAPs in the haloarchaeon Haloferax mediterranei. These PGAPs were visualized with two-dimensional gel electrophoresis (2-DE) and identified by matrix-assisted laser desorption ionization-tandem time of flight mass spectrometry (MALDI-TOF/TOF MS).

[Identification of the phaB genes and analysis of the PHBV precursor supplying pathway in Haloferax mediterranei].

Objective: Identification and characterization of the genes involved in precursor supplying for poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biosynthesis in the haloarchaeon Haloferax mediterranei.

Methods: By using BLAST (Basic Local Alignment Search Tool) search methodology, we obtained five genes (phaB1, phaB2, phaJ1, phaJ2 and phaJ3) that were possibly involved in the 3-hydroxyacyl-CoA precursor supplying for PHBV biosynthesis in H. mediterranei.

Wide distribution among halophilic archaea of a novel polyhydroxyalkanoate synthase subtype with homology to bacterial type III synthases.

Polyhydroxyalkanoates (PHAs) are accumulated as intracellular carbon and energy storage polymers by various bacteria and a few haloarchaea. In this study, 28 strains belonging to 15 genera in the family Halobacteriaceae were investigated with respect to their ability to synthesize PHAs and the types of their PHA synthases. Fermentation results showed that 18 strains from 12 genera could synthesize polyhydroxybutyrate (PHB) or poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV).