19 research outputs found
The status of the world's land and marine mammals: diversity, threat, and knowledge
Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action
Cleaner production on electrochemical removal of sulphonamide from wastewater using three-dimensional electrode system: characterisation and kinetics
Two distinct ferritin-like molecules in pseudomonas aeruginosa: the product of the bfrA gene is a bacterial ferritin (FtnA) and not a bacterioferritin (Bfr)
Two distinct types of ferritin-like molecules often coexist in bacteria, the heme binding bacterioferritins (Bfr) and the non-heme binding bacterial ferritins (Ftn). The early isolation of a ferritin-like molecule from Pseudomonas aeruginosa suggested the possibility of a bacterioferritin assembled from two different subunits [Moore, G. R., et al. (1994) Biochem. J. 304, 493-497]. Subsequent studies demonstrated the presence of two genes encoding ferritin-like molecules in P. aeruginosa, designated bfrA and bfrB, and suggested that two distinct bacterioferritins may coexist [Ma, J.-F., et al. (1999) J. Bacteriol. 181, 3730-3742]. In this report, we present structural evidence demonstrating that the product of the bfrA gene is a ferritin-like molecule not capable of binding heme that harbors a catalytically active ferroxidase center with structural properties similar to those characteristic of bacterial and archaeal Ftns and clearly distinct from those of the ferroxidase center typical of Bfrs. Consequently, the product of the bfrA gene in P. aeruginosa is a bacterial ferritin, which we propose should be termed Pa FtnA. These results, together with the previous characterization of the product of the bfrB gene as a genuine bacterioferritin (Pa BfrB) [Weeratunga, S. J., et al. (2010) Biochemistry 49, 1160-1175], indicate the coexistence of a bacterial ferritin (Pa FtnA) and a bacterioferritin (Pa BfrB) in P. aeruginosa. In agreement with this idea, we also obtained evidence demonstrating that release of iron from Pa BfrB and Pa FtnA is likely subject to different regulation in P. aerugionsa. Whereas the efficient release of iron stored in Pa FtnA requires only the input of electrons from a ferredoxin NADP reductase (Pa Fpr), the release of iron stored in Pa BfrB requires not only electron delivery by Pa Fpr but also the presence of a "regulator", the apo form of a bacterioferritin-associated ferredoxin (apo Pa Bfd). Finally, structural analysis of iron uptake in crystallo suggests a possible pathway for the internalization of ferroxidase iron into the interior cavity of Pa FtnA
Two Distinct Ferritin-like Molecules in Pseudomonas aeruginosa: The Product of the bfrA Gene Is a Bacterial Ferritin (FtnA) and Not a Bacterioferritin (Bfr)
Two distinct types of ferritin-like molecules often coexist in bacteria, the heme binding bacterioferritins (Bfr) and the non-heme binding bacterial ferritins (Ftn). The early isolation of a ferritin-like molecule from Pseudomonas aeruginosa suggested the possibility of a bacterioferritin assembled from two different subunits [Moore, G. R., et al. (1994) Biochem. J. 304, 493–497]. Subsequent studies demonstrated the presence of two genes encoding ferritin-like molecules in P. aeruginosa, designated bfrA and bfrB, and suggested that two distinct bacterioferritins may coexist [Ma, J.-F., et al. (1999) J. Bacteriol. 181, 3730–3742]. In this report, we present structural evidence demonstrating that the product of the bfrA gene is a ferritin-like molecule not capable of binding heme that harbors a catalytically active ferroxidase center with structural properties similar to those characteristic of bacterial and archaeal Ftns and clearly distinct from those of the ferroxidase center typical of Bfrs. Consequently, the product of the bfrA gene in P. aeruginosa is a bacterial ferritin, which we propose should be termed Pa FtnA. These results, together with the previous characterization of the product of the bfrB gene as a genuine bacterioferritin (Pa BfrB) [Weeratunga, S. J., et al. (2010) Biochemistry 49, 1160–1175], indicate the coexistence of a bacterial ferritin (Pa FtnA) and a bacterioferritin (Pa BfrB) in P. aeruginosa. In agreement with this idea, we also obtained evidence demonstrating that release of iron from Pa BfrB and Pa FtnA is likely subject to different regulation in P. aerugionsa. Whereas the efficient release of iron stored in Pa FtnA requires only the input of electrons from a ferredoxin NADP reductase (Pa Fpr), the release of iron stored in Pa BfrB requires not only electron delivery by Pa Fpr but also the presence of a “regulator”, the apo form of a bacterioferritin-associated ferredoxin (apo Pa Bfd). Finally, structural analysis of iron uptake in crystallo suggests a possible pathway for the internalization of ferroxidase iron into the interior cavity of Pa FtnA
Experimental study on parameter estimation and mechanism for the removal of turbidity from groundwater and synthetic water using Moringa oleifera
Characterisation of the Plasmodium falciparum Hsp70-Hsp90 organising protein (PfHop)
Malaria is caused by Plasmodium species, whose
transmission to vertebrate hosts is facilitated by mosquito
vectors. The transition from the cold blooded mosquito
vector to the host represents physiological stress to the
parasite, and additionally malaria blood stage infection is
characterised by intense fever periods. In recent years, it
has become clear that heat shock proteins play an essential
role during the parasite's life cycle. Plasmodium falciparum
expresses two prominent heat shock proteins: heat shock
protein 70 (PfHsp70) and heat shock protein 90 (PfHsp90).
Both of these proteins have been implicated in the
development and pathogenesis of malaria. In eukaryotes,
Hsp70 and Hsp90 proteins are functionally linked by an
essential adaptor protein known as the Hsp70–Hsp90
organising protein (Hop). In this study, recombinant P.
falciparum Hop (PfHop) was heterologously produced in E.
coli and purified by nickel affinity chromatography. Using
specific anti-PfHop antisera, the expression and localisation
of PfHop in P. falciparum was investigated. PfHop was
shown to co-localise with PfHsp70 and PfHsp90 in parasites
at the trophozoite stage. Gel filtration and coimmunoprecipitation
experiments suggested that PfHop
was present in a complex together with PfHsp70 and
PfHsp90. The association of PfHop with both PfHsp70 and
PfHsp90 suggests that this protein may mediate the
functional interaction between the two chaperones