An H-ferritin from the hydrothermal vent shrimp Rimicaris exoculata and its potential role in iron metabolism.

Rimicaris exoculata (Decapoda: Bresiliidae) is one of the dominant species among hydrothermal vent communities along the Mid-Atlantic Ridge. This shrimp can tolerate high concentrations of heavy metals such as iron, but the mechanisms used for detoxification and utilization of excess metals remain largely unknown. Ferritin is a major iron storage protein in most living organisms. The central heavy subunit of ferritin (H-ferritin) possesses ferroxidase activity and converts iron from Fe2+ to Fe3+, the non-toxic form used for storage. In the present study, the H-ferritin RexFrtH was identified in the hydrothermal vent shrimp R. exoculata, and found to be highly expressed in the gill, the main organ involved in bioaccumulation of metals, at both RNA and protein levels. Accumulation of RexFrtH decreased from efferent to afferent vessels, coinciding with the direction of water flow through the gills. Fe3+ was localized with RexFrtH, and in vitro iron-binding and ferroxidase assays using recombinant RexFrtH confirmed the high affinity for iron. Based on these results, we propose a model of iron metabolism in R. exoculata gills; ferrous iron from ambient hydrothermal water accumulates and is converted and stored in ferric form by RexFrtH as an iron reservoir when needed for metabolism, or excreted as an intermediate to prevent iron overload. The findings expand our understanding of the adaptation strategies used by shrimps inhabiting extreme hydrothermal vents to cope with extremely high heavy metal concentrations.

The complete mitogenome of the fairy shrimp Phallocryptus tserensodnomi (Crustacea: Anostraca: Thamnocephalidae).

The sequence of the mitochondrial genome (mitogenome) of the fairy shrimp Phallocryptus tserensodnomi Alonso & Ventura 2013 (Crustacea: Anostraca: Thamnocephalidae) has been determined. It is 16,493 bp with an AT-content of 65.4%, which encodes information of the typical 37 genes as all other metazoan mitogenomes. Both AT-content and putative control region of the genome show moderate values among all mitogenomes of the Branchiopoda sequenced to date. The mitochondrial gene order shows the same arrangement with the Artemiidae which is different from the pancrustacean ancestral pattern, due to translocation and inversion of two tRNA genes. Our results will provide important materials for not only phylogenetic but also biogeographic studies of the Anostraca.

The complete mitogenome of the Atlantic hydrothermal vent shrimp Rimicaris exoculata Williams & Rona 1986 (Crustacea: Decapoda: Alvinocarididae).

In this study we completely determined and analyzed the mitochondrial genome of the Mid-Atlantic Ridge hydrothermal-vent shrimp Rimicaris exoculata (Crustacea: Decapoda: Alvinocarididae). The circular molecule is 15,902 bp in size with an AT content of 65.7%, composed of the same 37 mitochondrial genes as in all other known metazoan mitogenomes. Sequence composition of the R. exoculata mitogenome is exceptionally similar to that of its Indian-Ocean congener R. kairei, which suggests the fact that they might diverge at a quite recent age. The genome exhibits an ancestral pancrustacean arrangement of mitochondrial genes that presents only the translocation/inversion of trnL-UUR from the ancestral arthropod pattern. Determination of the R. exoculata mitogenome can help to resolve the consensus Decapoda tree of life. It also provides more genetic information available for phylogenetics as well as population genetics on this extensively studied species from hydrothermal vents.

[Assessment of ecological environment benefits of reclaimed water reuse in Beijing].

With the rapid development of the social economy and the sustained growth of population, China is facing increasingly serious water problems, and reclaimed water utilization has become an effective measure to solve water shortage problem and to control further deterioration of the ecological environment. Reclaimed water utilization can not only save a lot of fresh water, but also reduce the environmental impact of wastewater discharge, and thus has great ecological environmental benefits, including resource, environmental and human health benefits and so on. This study used the opportunity cost method to construct an evaluation system for ecological environmental benefits of reclaimed water utilization, and Beijing was taken as an example to conduct an estimation of ecological environmental benefits of reclaimed water utilization. Research results indicated that the reclaimed water utilization in Beijing had considerable environmental benefits for ¥ 1.2 billion in 2010, in which replacement of fresh water accounted for the largest share. The benefits of environmental improvement and groundwater recharge were large, while the other benefits were small or negative. The ecological environment benefits of reclaimed water utilization in Beijing was about 1.8 times that of its direct economic benefits, showing that reclaimed water utilization was in accordance with sustainable development. Related methods and results will provide scientific basis to promote the development of reclaimed water utilization in our country.