18 research outputs found
Organizations should know their people: a behavioral economics approach
Public and private organizations are increasingly applying behavioral economics methods to a variety of issues such as mechanism design and incentive architecture. However, there has been little focus on how experimental tools used in behavioral economics can help companies learn more about their (current or prospective) workforce and, more specifically, about their employees’ tastes and inclinations. This has important implications for broader organizational performance since some designs/incentives are likely to affect only individuals with a particular disposition (e.g. risk averse or fairness oriented) but not others, or can even have opposite effects on individuals with different sets of preferences. In this commentary, we point out a number of promising avenues for the application of a behavioral economics lens to understand and manage people within organizations. A comprehensive case study is also provided
Correct Bgs1 function is important for CAR Integrity and maintenance of Ags1 and Bgs4 in the septum membrane.
<p><b>(A)</b> Fluorescence micrographs of CW stained <i>cps1-191</i> cells carrying Rlc1-RFP (ring) and GFP-Psy1 (plasma membrane). <i>cps1-191</i> cells growing in YES+S (S = 1.3M sorbitol) at 25°C were shifted to 37°C for 6 h and imaged. Medial z slide (upper panels) and maximum-intensity projections of 28 z slides at 0.3 μm intervals (lower panels) of the same cells are shown. <b>(B)</b> Three-dimensional reconstructions (28 z slides at 0.3 μm intervals) of cells grown as in A. Left, equatorial plane; right, longitudinal plane. <b>(C-E)</b> Time-lapses (one medial z slide, 5 min intervals, although in some cases only is shown 10 min interval as indicated) of CW-stained wild-type <b>(C)</b> and <i>cps1-191</i> (<b>D</b> and <b>E</b>) cells carrying Rlc1-RFP and Ags1-GFP or GFP-Bgs4. Wild type and <i>cps1-191</i> cells growing in YES+S at 25°C were shifted to 37°C for 1.5 h and filmed to capture ring formation, and Ags1 or Bgs4 arrival to the division site. Two <i>cps1-191</i> cells showing a sliding ring which does not constrict (left in D and E) and two <i>cps1-191</i> cells with a slow ring constriction and septum deposition (right in D and E) are shown. Arrowheads indicate synthesis of the septum wall in the absence of ring constriction. A dashed line is drawn as reference for the ring position. <b>(F</b> and <b>G)</b> Fluorescence micrographs of CW-stained wild-type (F) and <i>cps1-191</i> (G) cells carrying Rlc1-RFP, and GFP-Bgs4 or Ags1-GFP. Cells were grown as in A. Maximum-intensity projections of 28 z slides at 0.3 μm intervals (upper panels) and the corresponding three-dimensional reconstructions of the equatorial plane including the septum area (lower panels) of the complete cell are shown. In all the three-dimensional reconstructions, from the 28 slides acquired it was only selected those slides that cover the entire cell diameter. Scale bars, 5 μm.</p
Pxl1 is required for stable CAR and septum positioning in the middle of the cell.
<p><b>(A)</b> A Calcofluor White (CW) staining image of <i>pxl1</i>Δ cells with off-centered septa. <b>(B)</b> Histogram showing the indicated intervals of septum position measured as the percent of septum offset from the cell center: white bars, wild-type cells (n = 40); black bars, <i>pxl1</i>Δ cells (n = 142); dark grey bars, <i>pxl1</i>Δ <i>ags1</i><sup>+</sup>-<i>GFP</i> cells (n = 131); and light grey bars, <i>pxl1</i>Δ <i>GFP-bgs1</i><sup>+</sup> cells (n = 59). The position of the septum was measured with Image J software as described in the Materials and Methods section. <b>(C)</b> Time series of fluorescence micrographs (one medial z slide, 3 min intervals) of cells carrying Rlc1-RFP and GFP-Atb2. The first panel shows a wild-type cell with a centrally located ring that began to constrict at +24 min. The second panel shows a <i>pxl1</i>Δ cell with a ring that moved toward the upper pole at +15 min. Spindle microtubules appear at time 0. <b>(D)</b> Time courses of appearance of cortical nodes tracked with Rlc1-RFP (circle), completion of ring (square), onset of ring constriction (diamond), and ring sliding (triangle). Filled symbols are wild-type cells (circle n = 16; square n = 15; diamond n = 15), and open symbols are <i>pxl1</i>Δ cells (circle n = 40; square n = 50; diamond n = 45; triangle n = 27). <b>(E)</b> Time series of fluorescence micrographs (one medial z slide, 3 min intervals) of cells carrying GFP-Bgs1, Rlc1-RFP and GFP-Atb2. The first panel shows a wild-type cell where Bgs1 was detected in the cell middle at +15 min. The second panel shows a <i>pxl1</i>Δ cell with a ring that moved toward the lower pole at +18 min and where Bgs1 was detected in the cell middle at +15 min. Spindle microtubules appear at time 0. <b>(F)</b> Time series of fluorescence micrographs (one medial z slide, 3 min intervals) of cells carrying Ags1-GFP, Rlc1-RFP and GFP-Atb2. The first panel shows a wild-type cell where Ags1 was detected in the cell middle at +12 min. The second panel shows a <i>pxl1</i>Δ cell with a ring that moved toward the lower pole at +18 min where Ags1 was detected at +15 min. Spindle microtubules appear at time 0. Dashed line: reference for the ring position. Elapsed time is shown in minutes. Scale bars, 5 μm.</p
Cdc15 SH3 domain is necessary for proper concentration of Pxl1 at the CAR.
<p><b>(A)</b> Box plot showing the total fluorescence of GFP-Pxl1 in the cell middle of wild-type (n = 90) and <i>cdc15</i><sub>ΔSH3</sub> cells (n = 214). GFP-Pxl1 fluorescence was measured in cells stained with CW, and divided into four categories depending on the length of the septum in the cell: 1) no septum 2) early septum (less than 0.6 μm); 3) middle septum (0.6 to 1.2 μm); and 4) advanced septum (more than 1.2 μm). Total fluorescence was quantified by using Image J software as described in the Materials and Methods section. <b>(B)</b> Fluorescence micrographs showing representative septated wild-type and <i>cdc15</i><sub>ΔSH3</sub> cells carrying GFP-Pxl1, and used to measure the total fluorescence of GFP-Pxl1 in A. <b>(C)</b> Kymographs of fluorescence time series (one middle z slide, 2 min intervals) of wild-type and <i>cdc15</i><sub>ΔSH3</sub> cells stained with CW and carrying GFP-Pxl1. <b>(D)</b> Time series of fluorescence micrographs (one medial z slide, 3 min intervals) of wild-type (upper panels) and <i>cdc15</i><sub>ΔSH3</sub> (lower panels) cells carrying GFP-Pxl1 and RFP-Atb2. Spindle microtubules appear at time 0. <b>(E)</b> Total fluorescence of GFP-Pxl1 in the cell middle of the time series shown in D. Fluorescence was quantified along the time as described in A. <b>(F)</b> Time series of fluorescence micrographs (one medial z slide, 3 min intervals) of cells carrying GFP-Bgs1 and RFP-Atb2. The first panel shows a wild-type cell where the Bgs1 band was detected in the septum assembly site at +12 min. The second panel shows a <i>cdc15</i><sub>ΔSH3</sub> cell where the Bgs1 band was detected in the septum assembly site at +18 min. The third panel shows a <i>pxl1</i>Δ cell where the Bgs1 band was detected in the septum assembly site at +12 min. Spindle microtubules appear at time 0. Squares indicate the first detection of Bgs1 as a band in the septum assembly site in the wild-type. <b>(G)</b> Time courses of appearance of the GFP-Bgs1 band (diamond) and GFP-Bgs1 ring (square). Open symbols are wild-type cells, and filled symbols are <i>cdc15</i><sub>ΔSH3</sub> (upper graph) and <i>pxl1</i>Δ (lower graph) cells. The same wild-type cells were used in both graphs. Wild-type (diamond n = 19; square n = 19), <i>cdc15</i><sub>ΔSH3</sub> (diamond n = 24; square n = 24), and <i>pxl1</i>Δ cells (diamond n = 15; square n = 14). Elapsed time is shown in minutes. Scale bars, 5 μm.</p
Bgs1 and Pxl1 cooperation is essential for the septum synthesis.
<p><b>(A-D)</b> Transmission electron microscopy images of wild-type cells (A), <i>pxl1</i>Δ (B), P<i>nmt81-bgs1</i><sup>+</sup> (C), and <i>pxl1</i>Δ P<i>nmt81-bgs1</i><sup>+</sup> (D). Open arrowhead (in section B): Thick growing septum. Arrow (in section D): Projections of cell wall material that is laid down along the cell cortex. Arrowhead (in section D): Old thick septa without primary septum generated during earlier times of <i>bgs1</i><sup>+</sup> repression. Cells were grown to early log-phase in EMM+S and shifted to EMM+S+T for 40 h, and then processed for electron microscopy as described in the Material and Methods section.</p
Rho1 is involved in Pmk1 activation in response to cell wall stress.
<p>Strains MI200 (<i>pmk1-HA6H</i>, WT), LS201 (<i>rho1-596</i>), MI700 (<i>rho2Δ</i>), and LS202 (<i>rho1-596 rho2Δ</i>) were grown in YES medium to mid log-phase, and treated with (A) 0.6 M KCl, (B) 1 mM H<sub>2</sub>O<sub>2</sub>, or (C) 1 µg/ml Caspofungin. At different times Pmk1-HA6H was purified and both activated and total Pmk1 were detected by immunoblotting with anti-phospho-p42/44 and anti-HA antibodies, respectively. (D) Rho1 and Pmk1 play additive roles in cell survival during cell wall stress. Strains MI200 (WT), MI700 (<i>rho2Δ</i>), GB3 (<i>pck2Δ</i>), GB29 (<i>rho2Δ pck2Δ</i>), LS201 (<i>rho1-596</i>), LS202 (<i>rho1-596 rho2Δ</i>), LS203 (<i>rho1-596 pck2Δ</i>), MI102 (<i>pmk1Δ</i>) and LS209 (<i>rho1-596 pmk1Δ</i>) were grown in YES medium, and 10<sup>4</sup>, 10<sup>3</sup>, 10<sup>2</sup> and 10 cells were spotted onto YES plates supplemented with increased concentrations of Caspofungin. The plates were incubated for 4 days at 28°C before being photographed.</p
Cooperation of Bgs1 and Pxl1 is essential for CAR maintenance and septum formation.
<p><b>(A)</b> CW staining images of <i>cps1-191</i>, P<i>nmt41-pxl1</i><sup>+</sup> and <i>cps1-191</i> P<i>nmt41-pxl1</i><sup>+</sup> cells. Cells were grown at 25°C (permissive temperature for <i>cps1-191</i>) in the presence of thiamine (+T, <i>pxl1</i><sup>+</sup> repressed) for 24 h and imaged. <b>(B)</b> Histogram showing the indicated intervals of positions of the septa measured as the percent of septum offset from the cell center: white bars, <i>cps1-191</i> cells (n = 37); black bars, P<i>nmt41-pxl1</i><sup>+</sup> cells (n = 44 cells); and grey bars, <i>cps1-191</i> P<i>nmt41-pxl1</i><sup>+</sup> cells (n = 62 cells). The percentages of septum offset were calculated as described for the <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005358#pgen.1005358.g001" target="_blank">Fig 1B</a>. <b>(C)</b> Fluorescence micrographs of P<i>nmt81-bgs1</i><sup>+</sup> and <i>pxl1</i>Δ P<i>nmt81-bgs1</i><sup>+</sup> cells stained with CW and carrying Rlc1-GFP. Cells were grown to early log-phase in EMM+S (time 0 h), shifted to EMM+S+T for <i>bgs1</i><sup>+</sup> repression (times 15, 24 and 40 h + T), and imaged at the indicated times. Arrow: Cell with an open septum without the ring of Rlc1. Arrowhead: Cell with an aberrant ring of Rlc1. <b>(D)</b> Histograms showing the indicated percentages of septa and Rlc1 structures in P<i>nmt81-bgs1</i><sup>+</sup> (n = 150 cells or hypha units for each time), and <i>pxl1</i>Δ P<i>nmt81-bgs1</i><sup>+</sup> cells (n = 100 cells or hypha units for each time). Note that P<i>nmt81-bgs1</i><sup>+</sup> strains at 24 h of <i>bgs1</i><sup>+</sup> repression appear as hypha units, each being equivalent to several single cells. (<b>E</b>) Fluorescence micrographs of <i>Pnmt81-bgs1</i><sup>+</sup> (time 24 h of <i>bgs1</i><sup>+</sup> repression) and <i>pxl1</i>Δ <i>Pnmt81-bgs1</i><sup>+</sup> (times 0 and 24 h of <i>bgs1</i><sup>+</sup> repression) cells carrying Rlc1-RFP and Ags1-GFP or GFP-Bgs4. Cells were grown as in C and imaged at the indicated times. Arrow: concentration of Ags1-GFP or GFP-Bgs4 in the septum membrane. Scale bars, 5 μm.</p
Cooperation between Bgs1 and the SH3 Domain of Cdc15 is essential for CAR maintenance and septum formation.
<p><b>(A)</b> Fluorescence micrographs of <i>cdc15</i><sub>ΔSH3</sub>-<i>GFP</i> P<i>nmt81-bgs1</i><sup>+</sup> cells stained with CW and carrying Cdc15<sub>ΔSH3</sub>-GFP. Cells were grown to early log-phase in EMM+S (time 0 h), shifted to the same medium plus thiamine, EMM+S+T (times 15, 24 and 40 h, <i>bgs1</i><sup>+</sup> repressed) and imaged at the indicated times. Arrow: Cell with an open septum without the ring of Cdc15. Arrowhead: Cell with a disorganized ring of Cdc15. <b>(B)</b> Histograms showing the indicated percentages of septa and Cdc15 structures in the strains P<i>nmt81-bgs1</i><sup>+</sup> (n = 150 cells or hypha units were quantified for each time) and <i>cdc15</i><sub>ΔSH3</sub>-<i>GFP</i> P<i>nmt81-bgs1</i><sup>+</sup> (n = 100 cells or hypha units were quantified for each time). Note that P<i>nmt81-bgs1</i><sup>+</sup> strains after 24 h of <i>bgs1</i><sup>+</sup> repression appear as hypha units, each being equivalent to several single cells. (<b>C</b>) Fluorescence micrographs of P<i>nmt81-bgs1</i><sup>+</sup> and <i>cdc15</i><sub>ΔSH3</sub>-<i>GFP</i> P<i>nmt81-bgs1</i><sup>+</sup> cells stained with CW and carrying Ags1-RFP or RFP-Bgs4 after the indicated times of repression of <i>bgs1</i><sup>+</sup>. <b>(D)</b> Fluorescence micrographs of P<i>nmt81-bgs1</i><sup>+</sup>, P<i>nmt81-bgs1</i><sup>+</sup><i>pxl1</i>Δ and P<i>nmt81-bgs1</i><sup>+</sup><i>cdc15</i><sub>ΔSH3</sub> cells carrying the hypomorphic version of Bgs1 GFP-Cps1-191, and wild-type cells carrying GFP-Bgs1 used as Bgs1 localization control. Since <i>cps1-191</i> allele is lethal in <i>pxl1</i>Δ and <i>cdc15</i><sub>ΔSH3</sub> backgrounds, strains are maintained alive with an inducible version of <i>bgs1</i><sup>+</sup> (P<i>nmt81-bgs1</i><sup>+</sup>). Cells were grown at 25°C (permissive temperature for <i>cps1-191</i> cells) in EMM+S (time 0 h, <i>bgs1</i><sup>+</sup> induced) and shifted to EMM+S+T (time 24 h +T, <i>bgs1</i><sup>+</sup> repressed) to visualize cell phenotype and GFP-Cps1-191 localization. Scale bars, 5 μm.</p
Specific detection of fission yeast primary septum reveals septum and cleavage furrow ingression during early anaphase independent of mitosis completion
<div><p>It is widely accepted in eukaryotes that the cleavage furrow only initiates after mitosis completion. In fission yeast, cytokinesis requires the synthesis of a septum tightly coupled to cleavage furrow ingression. The current cytokinesis model establishes that simultaneous septation and furrow ingression only initiate after spindle breakage and mitosis exit. Thus, this model considers that although Cdk1 is inactivated at early-anaphase, septation onset requires the long elapsed time until mitosis completion and full activation of the Hippo-like SIN pathway. Here, we studied the precise timing of septation onset regarding mitosis by exploiting both the septum-specific detection with the fluorochrome calcofluor and the high-resolution electron microscopy during anaphase and telophase. Contrarily to the existing model, we found that both septum and cleavage furrow start to ingress at early anaphase B, long before spindle breakage, with a slow ingression rate during anaphase B, and greatly increasing after telophase onset. This shows that mitosis and cleavage furrow ingression are not concatenated but simultaneous events in fission yeast. We found that the timing of septation during early anaphase correlates with the cell size and is regulated by the corresponding levels of SIN Etd1 and Rho1. Cdk1 inactivation was directly required for timely septation in early anaphase. Strikingly the reduced SIN activity present after Cdk1 loss was enough to trigger septation by immediately inducing the medial recruitment of the SIN kinase complex Sid2-Mob1. On the other hand, septation onset did not depend on the SIN asymmetry establishment, which is considered a hallmark for SIN activation. These results recalibrate the timing of key cytokinetic events in fission yeast; and unveil a size-dependent control mechanism that synchronizes simultaneous nuclei separation with septum and cleavage furrow ingression to safeguard the proper chromosome segregation during cell division.</p></div