Assigning a function to a conserved archaeal metallo-β-lactamase from Haloferax volcanii

The metallo-β-lactamase family of enzymes comprises a large group of proteins with diverse functions in the metabolism of the cell. Among others, this superfamily contains proteins which are involved in DNA and RNA metabolism, acting as nucleases in e.g. repair and maturation. Many proteins have been annotated in prokaryotic genomes as being potential metallo-β-lactamases, but very often the function has not been proven. The protein HVO_2763 from Haloferax volcanii is such a potential metallo-β-lactamase. HVO_2763 has sequence similarity to the metallo-β-lactamase tRNase Z, a tRNA 3′ processing endonuclease. Here, we report the characterisation of this metallo-β-lactamase HVO_2763 in the halophilic archaeon Haloferax volcanii. Using different in vitro assays with the recombinant HVO_2763, we could show that the protein does not have tRNA 3′ processing or exonuclease activity. According to transcriptome analyses of the HVO_2763 deletion strain, expression of proteins involved in membrane transport is downregulated in the mutant. Therefore, HVO_2763 might be involved directly or indirectly in membrane transport

Corrosion-resistant plastic pipes with barrier layers to prevent permeation of hydrocarbons: Safe transport of contaminated fluids from industrial processes or exploration

Corrosion-resistant plastic pipe systems are a good option for transporting aqueous solutions resulting from industrial separation processes or separation processes involved in oil or natural gas exploration, which are potentially environmentally hazardous, since they are contaminated with volatile organic hydrocarbons and frequently also with brines. Safe containment of these environmentally relevant components in the pipe systems over many years of operation is the concern of every responsible operator. In the past, leakages caused by corrosion damage on steel pipes or by permeation of hydrocarbons through pipes made of polyethylene (PE) have resulted in environmental damages, which required extensive remediation measures. In view of proven permeation losses with plain polyethylene pipes of the kind also used for drinking water, the suitability of pressure pipes made of polyethylene (PE 100-RC) and equipped with an external aluminium barrier layer (SLA® barrier pipe) as well as an outer protective sheath was to be demonstrated. Since permeation is a slow process involving transport of substances through a solid body, pipes with such a barrier layer were tested and compared to the same pipes which did not have a barrier layer over a 4-year time period in the context of field- and laboratory trials. For tests performed during real operation of a crude oil production facility, the composition of the fluid was given by the real case. For systematic laboratory tests, clearly specified test liquids which came as close as possible to providing a representative sample were used. In order to simulate drastic conditions, test liquids were saturated solutions consisting of various volatile hydrocarbons, some of them also chlorinated. A further test liquid was a mixture of pure volatile hydrocarbons with a 10% share of aromatic toluene. In contrast to single-layer polyethylene pipes, the PE pipes featuring a barrier layer (SLA) were shown to be resistant to permeation of all of the dissolved volatile organic ingredients examined. Even under tougher test conditions in the laboratory (which involved pure volatile hydrocarbons), analytic measurements after two years showed some traces of hydrocarbons in the protective sheath beyond the aluminium barrier layer of the SLA pipes only, though not in the gaseous phase outside the barrier layer pipe (SLA). Thus, PE pipes equipped with an aluminium barrier layer can be recommended for loss-free transport of aqueous liquids containing hydrocarbons, such as production water in crude oil and natural gas facilities, and are an alternative for pipes exclusively made of polyethylene. Combined with permanent monitoring for the purpose of damage detection, they comply with the strictest environmental requirements in effect, thus reliablyprotecting the environment

Distribution, habitat, and conservation status of the near-threatened Japanese Paradise-Flycatcher (Terpsiphone atrocaudata periophthalmica) on Lanyu, Taiwan

The near-threatened Japanese Paradise-Flycatcher (Terpsiphone atrocaudata) consists of three subspecies, one of which, T. a. periophthalmica, has an important population on Lanyu, Taiwan. After briefly reviewing the species' conservation status in its breeding range, we describe our field work in Lanyu during the breeding seasons of 2009 and 2010. We first established that the territory size of a male flycatcher is around 1.16 hectares. We then visited 224 1-hectare grid cells randomly distributed across Lanyu and established 120 presence grid cells. We then used these presence grid cells and nine environmental data layers to build an ensemble distribution model using the software Maxent. The model showed that the Japanese Paradise-Flycatcher prefers relatively wet forest habitats at elevations of 50-300 m. Using the model, we estimated that the extent of suitable habitat covered approximately 12.0 km² (or 26%) of Lanyu's surface area, which could hold approximately 1000 male territories. Forest cover increased between 1948 and 2006 by approximately 7.6 km² (or 16%) of Lanyu's surface area, which, all other things being equal, should have resulted in a population increase of around 30%. Given the absence of current threats, the Lanyu population is assumed to be relatively stable. Given this new information and our review of the species' conservation status, we suggest that the species may be down-listed to "least concern." However, if the distinct subspecies T. a. periophthalmica would be elevated to species status or be considered two independent conservation units (one in Lanyu and one in Batanes, Philippines), its conservation status would be much more precarious given it only occurs in five known localities (Lanyu and four islands in Batanes) of limited geographic range, and a population size of approximately 1000 males in Lanyu and an unknown population size in Batanes. Therefore, we conclude that more information is needed about (1) the species' status in Batanes, (2) its migration and wintering grounds, and (3) the taxonomic status of the three subspecies

The Archaeal Lsm Protein Binds to Small RNAs*

Proteins of the Lsm family, including eukaryotic Sm proteins and bacterial Hfq, are key players in RNA metabolism. Little is known about the archaeal homologues of these proteins. Therefore, we characterized the Lsm protein from the haloarchaeon Haloferax volcanii using in vitro and in vivo approaches. H. volcanii encodes a single Lsm protein, which belongs to the Lsm1 subfamily. The lsm gene is co-transcribed and overlaps with the gene for the ribosomal protein L37e. Northern blot analysis shows that the lsm gene is differentially transcribed. The Lsm protein forms homoheptameric complexes and has a copy number of 4000 molecules/cell. In vitro analyses using electrophoretic mobility shift assays and ultrasoft mass spectrometry (laser-induced liquid bead ion desorption) showed a complex formation of the recombinant Lsm protein with oligo(U)-RNA, tRNAs, and an small RNA. Co-immunoprecipitation with a FLAG-tagged Lsm protein produced in vivo confirmed that the protein binds to small RNAs. Furthermore, the co-immunoprecipitation revealed several protein interaction partners, suggesting its involvement in different cellular pathways. The deletion of the lsm gene is viable, resulting in a pleiotropic phenotype, indicating that the haloarchaeal Lsm is involved in many cellular processes, which is in congruence with the number of protein interaction partners