Comparative proteomics of thylakoids from Arabidopsis grown in laboratory and field conditions

Compared to controlled laboratory conditions, plant growth in the field is rarely optimal since it is frequently challenged by large fluctuations in light and temperature which lower the efficiency of photosynthesis and lead to photo-oxidative stress. Plants grown under natural conditions therefore place an increased onus on the regulatory mechanisms that protect and repair the delicate photosynthetic machinery. Yet, the exact changes in thylakoid proteome composition which allow plants to acclimate to the natural environment remain largely unexplored. Here, we use quantitative label-free proteomics to demonstrate that field-grown Arabidopsis plants incorporate aspects of both the low and high light acclimation strategies previously observed in laboratory-grown plants. Field plants showed increases in the relative abundance of ATP synthase, cytochrome b6f, ferredoxin-NADP+ reductases (FNR1 and FNR2) and their membrane tethers TIC62 and TROL, thylakoid architecture proteins CURT1A, CURT1B, RIQ1, and RIQ2, the minor monomeric antenna complex CP29.3, rapidly-relaxing non-photochemical quenching (qE)-related proteins PSBS and VDE, the photosystem II (PSII) repair machinery and the cyclic electron transfer complexes NDH, PGRL1B, and PGR5, in addition to decreases in the amounts of LHCII trimers composed of LHCB1.1, LHCB1.2, LHCB1.4, and LHCB2 proteins and CP29.2, all features typical of a laboratory high light acclimation response. Conversely, field plants also showed increases in the abundance of light harvesting proteins LHCB1.3 and CP29.1, zeaxanthin epoxidase (ZEP) and the slowly-relaxing non-photochemical quenching (qI)-related protein LCNP, changes previously associated with a laboratory low light acclimation response. Field plants also showed distinct changes to the proteome including the appearance of stress-related proteins ELIP1 and ELIP2 and changes to proteins that are largely invariant under laboratory conditions such as state transition related proteins STN7 and TAP38. We discuss the significance of these alterations in the thylakoid proteome considering the unique set of challenges faced by plants growing under natural conditions

STN7 is not essential for developmental acclimation of Arabidopsis to light intensity

Plants respond to changing light intensity in the short term through regulation of light harvesting, electron transfer, and metabolism to mitigate redox stress. A sustained shift in light intensity leads to a long-term acclimation response (LTR). This involves adjustment in the stoichiometry of photosynthetic complexes through de novo synthesis and degradation of specific proteins associated with the thylakoid membrane. The light-harvesting complex II (LHCII) serine/threonine kinase STN7 plays a key role in short-term light harvesting regulation and was also suggested to be crucial to the LTR. Arabidopsis plants lacking STN7 (stn7) shifted to low light experience higher photosystem II (PSII) redox pressure than the wild type or those lacking the cognate phosphatase TAP38 (tap38), while the reverse is true at high light, where tap38 suffers more. In principle, the LTR should allow optimisation of the stoichiometry of photosynthetic complexes to mitigate these effects. We used quantitative label-free proteomics to assess how the relative abundance of photosynthetic proteins varied with growth light intensity in wild-type, stn7, and tap38 plants. All plants were able to adjust photosystem I, LHCII, cytochrome b6f, and ATP synthase abundance with changing white light intensity, demonstrating neither STN7 nor TAP38 is crucial to the LTR per se. However, stn7 plants grown for several weeks at low light (LL) or moderate light (ML) still showed high PSII redox pressure and correspondingly lower PSII efficiency, CO2 assimilation, and leaf area compared to wild-type and tap38 plants, hence the LTR is unable to fully ameliorate these symptoms. In contrast, under high light growth conditions the mutants and wild type behaved similarly. These data are consistent with the paramount role of STN7-dependent LHCII phosphorylation in tuning PSII redox state for optimal growth in LL and ML conditions

British civil protection, the industrial and the military reaction to external and internal threats 1900-1990

SIGLEAvailable from British Library Document Supply Centre- DSC:DX175383 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Asset pricing, time-varying risk premia and interest rate risk

Journal of Banking and Finance213315-335JBFI

Flood Insurance and Claims: The Impact of the Community Rating System

The Community Rating System (CRS) was introduced to encourage community-level flood mitigation and increase household-level flood insurance uptake through the National Flood Insurance Program (NFIP). Using historical data of policies-in-force and flood damage claims from 1998-2014 for all NFIP communities in Alabama and Mississippi, we estimate the relationship between community participation in the CRS and the number of policies-in-force, as well on flood damage claims. We find a significant, positive, and generally increasing effect of CRS participation on insurance uptake. Reduced flood damage claims are found to be limited to communities with a very high level of CRS participation (Class 5) only

Financial Stability in European Banking: The Role of Common Factors

In this paper, I investigate the development and determinants of CDS spreads for 18 major European banks between December 2001 and January 2004 applying factor analysis to daily data. Two clear-cut conclusions can be drawn. First, the dominating first common factor that explains 88 percent of all variation in the system, impacts on all banks in a similar direction. This suggests a strong market integration. However the size of the response of each bank’s CDS spread to the first common factor differs substantially, probably reflecting differences in individual bank’s exposure and riskiness. Second, the first common factor appears significantly related to the European P/E ratio and the European-wide 2-year nominal interest rate. This finding suggests that the common factor may be interpreted as a general indicator of market conditions. Copyright Springer Science + Business Media, LLC 2006credit default swap spreads, risk premium, financial integration,