Personality type differences between Ph.D. climate researchers and the general public: implications for effective communication

Effectively communicating the complexity of climate change to the public is an important goal for the climate change research community, particularly for those of us who receive public funds. The challenge of communicating the science of climate change will be reduced if climate change researchers consider the links between personality types, communication tendencies and learning preferences. Jungian personality type is one of many factors related to an individual’s preferred style of taking in and processing information, i.e., preferred communication style. In this paper, we demonstrate that the Jungian personality type profile of interdisciplinary, early career climate researchers is significantly different from that of the general population in the United States. In particular, Ph.D. climate researchers tend towards Intuition and focus on theories and the “big picture”, while the U.S. general population tends towards Sensing and focuses on concrete examples and experience. There are other differences as well in the way the general public as a group prefers to take in information, make decisions, and deal with the outer world, compared with the average interdisciplinary climate scientist. These differences have important implications for communication between these two groups. We suggest that climate researchers will be more effective in conveying their messages if they are aware of their own personality type and potential differences in preferred learning and communication styles between themselves and the general public (and other specific audiences), and use this knowledge to more effectively target their audience

Iron-induced oligomerization of human FXN81-210 and bacterial CyaY frataxin and the effect of iron chelators

Patients suffering from the progressive neurodegenerative disease Friedreich’s ataxia have reduced expression levels of the protein frataxin. Three major isoforms of human frataxin have been identified, FXN42-210, FXN56-210 and FXN81-210, of which FXN81-210 is considered to be the mature form. Both long forms, FXN42-210 and FXN56-210, have been shown to spontaneously form oligomeric particles stabilized by the extended N-terminal sequence. The short variant FXN81-210, on other hand, has only been observed in the monomeric state. However, a highly homologous E. coli frataxin CyaY, which also lacks an N-terminal extension, has been shown to oligomerize in the presence of iron. To explore the mechanisms of stabilization of short variant frataxin oligomers we compare here the effect of iron on the oligomerization of CyaY and FXN81-210. Using dynamic light scattering, small-angle X-ray scattering, electron microscopy (EM) and cross linking mass spectrometry (MS), we show that at aerobic conditions in the presence of iron both FXN81-210 and CyaY form oligomers. However, while CyaY oligomers are stable over time, FXN81-210 oligomers are unstable and dissociate into monomers after about 24 h. EM and MS studies suggest that within the oligomers FXN81-210 and CyaY monomers are packed in a head-to-tail fashion in ring-shaped structures with potential iron-binding sites located at the interface between monomers. The higher stability of CyaY oligomers can be explained by a higher number of acidic residues at the interface between monomers, which may result in a more stable iron binding. We also show that CyaY oligomers may be dissociated by ferric iron chelators deferiprone and DFO, as well as by the ferrous iron chelator BIPY. Surprisingly, deferiprone and DFO stimulate FXN81-210 oligomerization, while BIPY does not show any effect on oligomerization in this case. The results suggest that FXN81-210 oligomerization is primarily driven by ferric iron, while both ferric and ferrous iron participate in CyaY oligomer stabilization. Analysis of the amino acid sequences of bacterial and eukaryotic frataxins suggests that variations in the position of the acidic residues in helix 1, β-strand 1 and the loop between them may control the mode of frataxin oligomerization

DLS studies of iron-dependent oligomerization of human frataxin FXN^81-210.

<p><b>A</b>) Measurements after 30 min of incubation with iron at 2:1 equivalents of iron-to-protein (magenta), 4:1 (green), and 10:1 (blue). <b>B</b>) Measurements after 60 min of incubation showing buildup of oligomers. In black is monomeric human FXN^81-210 without the addition of iron. On the x-axis is the hydrodynamic radius of the particles and on the y-axis is the volume percentage of particles.</p

DLS studies of iron-dependent oligomerization of <i>E</i>. <i>coli</i> CyaY.

<p><b>A</b>) CyaY was incubated for 1 h at 2:1 iron-to-protein ratio (green); 6:1, magenta; 10:1, blue. Dashed lines show the same sample after 26 h of incubation. In black, monomeric CyaY without addition of iron. On the x-axis the hydrodynamic radius and on the y-axis the volume-percentage of particles are shown. <b>B</b>) CyaY oligomerization with and without DFO. The protein was incubated at 6:1 (red) and 8:1 (green) iron equivalents; in black the protein without iron addition; dashed line show the sample after the addition of DFO.</p

The interface between subunits in the head-to-tail arrangement.

<p><b>A</b>) Human frataxin interface with residues D112, D115, D122, and D124 marked in magenta. The N-terminus is colored in pink and the different monomers within the dimer are shown in yellow (head) and green (tail). A crystal structure (PDB entry 1EKG) was used for preparing the figure. <b>B</b>) CyaY interface and the residues making up the potential metal binding sites are shown. Residues H7, E19, D22, and D23, which may build up the first metal binding site, are shown as red sticks; D3, H58, and D25 may participate in the second site (yellow sticks); and H70, D29, and E44 (blue sticks) in the third. Gray spheres show Europium ions bound in the 2P1X crystal structure. Residues involved in metal binding in the crystal structures of CyaY in complex with Co and/or Eu are labeled. The different monomers in the dimer are shown in green (head) and blue (tail). Crystal structures (PDB entry 2P1X, 2EFF, and 1EW4) were used in the preparation of the figue.</p

Iron-induced oligomerization of human FXN^81-210 and bacterial CyaY frataxin and the effect of iron chelators

<div><p>Patients suffering from the progressive neurodegenerative disease Friedreich’s ataxia have reduced expression levels of the protein frataxin. Three major isoforms of human frataxin have been identified, FXN^42-210, FXN^56-210 and FXN^81-210, of which FXN^81-210 is considered to be the mature form. Both long forms, FXN^42-210 and FXN^56-210, have been shown to spontaneously form oligomeric particles stabilized by the extended N-terminal sequence. The short variant FXN^81-210, on other hand, has only been observed in the monomeric state. However, a highly homologous <i>E</i>. <i>coli</i> frataxin CyaY, which also lacks an N-terminal extension, has been shown to oligomerize in the presence of iron. To explore the mechanisms of stabilization of short variant frataxin oligomers we compare here the effect of iron on the oligomerization of CyaY and FXN^81-210. Using dynamic light scattering, small-angle X-ray scattering, electron microscopy (EM) and cross linking mass spectrometry (MS), we show that at aerobic conditions in the presence of iron both FXN^81-210 and CyaY form oligomers. However, while CyaY oligomers are stable over time, FXN^81-210 oligomers are unstable and dissociate into monomers after about 24 h. EM and MS studies suggest that within the oligomers FXN^81-210 and CyaY monomers are packed in a head-to-tail fashion in ring-shaped structures with potential iron-binding sites located at the interface between monomers. The higher stability of CyaY oligomers can be explained by a higher number of acidic residues at the interface between monomers, which may result in a more stable iron binding. We also show that CyaY oligomers may be dissociated by ferric iron chelators deferiprone and DFO, as well as by the ferrous iron chelator BIPY. Surprisingly, deferiprone and DFO stimulate FXN^81-210 oligomerization, while BIPY does not show any effect on oligomerization in this case. The results suggest that FXN^81-210 oligomerization is primarily driven by ferric iron, while both ferric and ferrous iron participate in CyaY oligomer stabilization. Analysis of the amino acid sequences of bacterial and eukaryotic frataxins suggests that variations in the position of the acidic residues in helix 1, β-strand 1 and the loop between them may control the mode of frataxin oligomerization.</p></div

Negative staining TEM images of iron-induced FXN^81-210 oligomers.

<p><b>A</b>) Monomeric FXN^81-210. <b>B)</b> FXN^81-210 after 30 min of incubation with iron at 6:1 of iron-to-protein molar ratio. Ring-shaped particles are marked by black circles. <b>C</b>) FXN^81-210 incubated with iron at 6:1 molar ratio of iron-to-protein and with deferiprone added. <b>D</b>) FXN^81-210 incubated with iron at 6:1 molar ratio of iron-to-protein and with DFO added. Ring-shaped particles and larger spherical particles are marked by black circles. <b>E</b>) Class averages of the ring-shaped structures obtained from 1265 particles. The tetrameric character of the ring-structures can be clearly seen on some of the class averages. The EM images have a magnification of 55,000x.</p

Average size and distribution of particles of CyaY obtained from DLS measurements and the effect of iron chelators.

<p>Average size and distribution of particles of CyaY obtained from DLS measurements and the effect of iron chelators.</p

DLS studies of iron-dependent oligomerization of human frataxin FXN^81-210.

<p><b>A</b>) Measurements after 30 min of incubation with iron at 2:1 equivalents of iron-to-protein (magenta), 4:1 (green), and 10:1 (blue). <b>B</b>) Measurements after 60 min of incubation showing buildup of oligomers. In black is monomeric human FXN^81-210 without the addition of iron. On the x-axis is the hydrodynamic radius of the particles and on the y-axis is the volume percentage of particles.</p