Nitrogen metabolism in haloarchaea

The nitrogen cycle (N-cycle), principally supported by prokaryotes, involves different redox reactions mainly focused on assimilatory purposes or respiratory processes for energy conservation. As the N-cycle has important environmental implications, this biogeochemical cycle has become a major research topic during the last few years. However, although N-cycle metabolic pathways have been studied extensively in Bacteria or Eukarya, relatively little is known in the Archaea. Halophilic Archaea are the predominant microorganisms in hot and hypersaline environments such as salted lakes, hot springs or salted ponds. Consequently, the denitrifying haloarchaea that sustain the nitrogen cycle under these conditions have emerged as an important target for research aimed at understanding microbial life in these extreme environments. The haloarchaeon Haloferax mediterranei was isolated 20 years ago from Santa Pola salted ponds (Alicante, Spain). It was described as a denitrifier and it is also able to grow using NO3-, NO2- or NH4+ as inorganic nitrogen sources. This review summarizes the advances that have been made in understanding the N-cycle in halophilic archaea using Hfx mediterranei as a haloarchaeal model. The results obtained show that this microorganism could be very attractive for bioremediation applications in those areas where high salt, nitrate and nitrite concentrations are found in ground waters and soils.

Constructing an Indigenous Model of the Self to Address Cultural and Mental Health Issues in the Canadian Subarctic

Since the last decades, academic research has paid much attention to the phenomenon of revitalizing indigenous cultures and, more precisely, the use of traditional indigenous healing methods both to deal with individuals' mental health problems and with broader cultural issues. The re-evaluation of traditional indigenous healing practices as a mode of psychotherapeutic treatment has been perhaps one of the most interesting sociocultural processes in the postmodern era. In this regard, incorporating indigenous forms of healing in a contemporary framework of indigenous mental health treatment should be interpreted not simply as an alternative therapeutic response to the clinical context of Western psychiatry, but also constitutes a political response on the part of ethno-cultural groups that have been stereotyped as socially inferior and culturally backward. As a result, a postmodern form of "traditional healing" developed with various forms of knowledge, rites and the social uses of medicinal plants, has been set in motion on many Canadian indigenous reserves over the last two decades.