Application of spectrally resolved fluorescence induction to study light-induced nonphotochemical quenching in algaeBrief Communications

R. Kaňa

Photosynthetica 2018, 56(1):132-138 | DOI: 10.1007/s11099-018-0780-1

The light-induced nonphotochemical quenching (NPQ) can safely dissipate excess of absorbed light to heat. Here we describe an application of spectrally resolved fluorescence induction (SRFI) method for studying spectral variability of NPQ. The approach allows detection of spectrally-resolved nonphotochemical quenching (NPQ_λ) representing NPQ dependency on fluorescence emission wavelength in the whole spectral range of fluorescence emission. The experimental approach is briefly described and NPQ_λ is studied for the cryptophyte alga Rhodomonas salina and for green alga Chlorella sp. We confirm presence...

Fluorescence induction of photosynthetic bacteriaArticle

G. Sipka, M. Kis, J. L. Smart, P. Maróti

Photosynthetica 2018, 56(1):125-131 | DOI: 10.1007/s11099-017-0756-6

The kinetics of bacteriochlorophyll fluorescence in intact cells of the purple nonsulfur bacterium Rhodobacter sphaeroides were measured under continuous and pulsed actinic laser diode (808 nm wavelength and maximum 2 W light power) illumination on the micro- and millisecond timescale. The fluorescence induction curve was interpreted in terms of a combination of photochemical and triplet fluorescence quenchers and was demonstrated to be a reflection of redox changes and electron carrier dynamics. By adjustment of the conditions of single and multiple turnovers of the reaction center, we obtained 11 ms^-1 and 120 μs^-1...

Chlorophyll fluorescence emission spectroscopy of oxygenic organisms at 77 KReview

J. J. Lamb, G. Røkke, M. F. Hohmann-Marriott

Photosynthetica 2018, 56(1):105-124 | DOI: 10.1007/s11099-018-0791-y

Photosynthetic fluorescence emission spectra measurement at the temperature of 77 K (-196°C) is an often-used technique in photosynthesis research. At low temperature, biochemical and physiological processes that modulate fluorescence are mostly abolished, and the fluorescence emission of both PSI and PSII become easily distinguishable. Here we briefly review the history of low-temperature chlorophyll fluorescence methods and the characteristics of the acquired emission spectra in oxygen-producing organisms. We discuss the contribution of different photosynthetic complexes and physiological processes to fluorescence emission at 77 K in cyanobacteria,...

Chlorophyll a fluorescence induction: Can just a one-second measurement be used to quantify abiotic stress responses?Review

A. Stirbet, D. Lazár, J. Kromdijk, Govindjee

Photosynthetica 2018, 56(1):86-104 | DOI: 10.1007/s11099-018-0770-3

Chlorophyll (Chl) a fluorescence induction (transient), measured by exposing dark-adapted samples to high light, shows a polyphasic rise, which has been the subject of extensive research over several decades. Several Chl fluorescence parameters based on this transient have been defined, the most widely used being the F_V [= (F_M-F₀)]/F_M ratio as a proxy for the maximum quantum yield of PSII photochemistry. However, considerable additional information may be derived from analysis of the shape of the fluorescence transient. In fact, several performance indices (PIs) have been defined, which are suggested...

On Otto Warburg, Nazi Bureaucracy and the difficulties of moral judgmentArticle

K. Nickelsen

Photosynthetica 2018, 56(1):75-85 | DOI: 10.1007/s11099-018-0773-0

Twentieth-century photosynthesis research had strong roots in Germany, with the cell physiologist Otto H. Warburg being among its most influential figures. He was also one of the few scientists of Jewish ancestry who kept his post as a director of a research institution throughout the Nazi period. Based on archival sources, the paper investigates Warburg's fate during these years at selected episodes. He neither collaborated with the regime nor actively resisted; he was harrassed by bureaucracy and denunciated to the secret police, but saved by powerful figures in economy, politics, and science. Warburg reciprocated this favour with problematic testimonies...

Synthesis and characterization of a cobalt(II) tetrakis(3-fluorophenyl) porphyrin with a built-in 4-vinylphenyl surface attachment moietyArticle

D. Khusnutdinova, M. Flores, A. M. Beiler, G. F. Moore

Photosynthetica 2018, 56(1):67-74 | DOI: 10.1007/s11099-018-0783-y

Metalloporphyrins serve important roles in biology and as components in emerging technological assemblies for energy conversion. In this report, we describe the synthesis and characterization of a novel cobalt(II) 5,10,15,20-tetrakis (3-fluorophenyl)porphyrin bearing a 4-vinylphenyl surface attachment group at a beta position on the macrocycle. Electrochemical measurements show the 3-fluorophenyl groups at the meso positions of the porphyrin perturb the reduction potentials of the complex to more positive values as compared to non-fluorinated analogs, thus allowing access to reduced cobalt porphyrin species at significantly less negative applied bias...

Chloroplast ribonucleoprotein-like proteins of the moss Physcomitrella patens are not involved in RNA stability and RNA editingBrief Communications

H. Uchiyama, M. Ichinose, M. Sugita

Photosynthetica 2018, 56(1):62-66 | DOI: 10.1007/s11099-017-0755-7

Many RNA recognition motif (RRM)-containing proteins are known to exist in chloroplasts. Major members of the RRM protein family, which are chloroplast ribonucleoproteins (cpRNPs), have been investigated in seed plants, including tobacco and Arabidopsis thaliana, but never in early land plants, such as bryophytes. In this study, we surveyed RRM proteins encoded in the moss Physcomitrella patens genome and predicted 25 putative chloroplast RRM proteins. Among them, two RRM-containing proteins, PpRBP2a and PpRBP2b, resembled cpRNPs and were thus referred to as cpRNP-like proteins. However, knockout mutants of either one or two PpRBP2...

RNA editing of plastid-encoded genesReview

Y. Lu

Photosynthetica 2018, 56(1):48-61 | DOI: 10.1007/s11099-017-0761-9

RNA editing is post-transcriptional modification to RNA molecules. In plants, RNA editing primarily occurs to two energy-producing organelles: plastids and mitochondria. Organelle RNA editing is often viewed as a mechanism of correction to compensate for defects or mutations in haploid organelle genomes. A common type of organelle RNA editing is deamination from cytidine to uridine. Cytidine-to-uridine plastid RNA editing is carried out by the RNA editing complex which consists of at least four types of proteins: pentatricopeptide repeat proteins, RNA editing interacting proteins/multiple organellar RNA editing factors, organelle RNA recognition motif...

On oxygen production by photosynthesis: A viewpointBrief Communications

A. Yu. Borisov, L. O. Björn

Photosynthetica 2018, 56(1):44-47 | DOI: 10.1007/s11099-017-0738-8

In this brief communication we provide an estimate of the part of the incident solar energy used for oxygen evolution as well as the time, in years, needed for the generation of the present amount of molecular oxygen in the biosphere by photosynthesis on land and in the ocean. We find this to be ≈3,000 yr. We also find that the ocean produces 22% more oxygen than the land surface.

Living off the Sun: chlorophylls, bacteriochlorophylls and rhodopsinsReview

A. W. D. Larkum, R. J. Ritchie, J. A. Raven

Photosynthetica 2018, 56(1):11-43 | DOI: 10.1007/s11099-018-0792-x

Pigments absorbing 350-1,050 nm radiation have had an important role on the Earth for at least 3.5 billion years. The ion pumping rhodopsins absorb blue and green photons using retinal and pump ions across cell membranes. Bacteriochlorophylls (BChl), absorbing in the violet/blue and near infra red (NIR), power anoxygenic photosynthesis, with one photoreaction centre; and chlorophylls (Chl), absorbing in the violet/blue and red (occasionally NIR) power oxygenic photosynthesis, with two photoreaction centres. The accessory (bacterio)chlorophylls add to the spectral range (bandwidth) of photon absorption, e.g., in algae living at depth in clear...

ForewordArticle

Julian J. Eaton-Rye

Photosynthetica 2018, 56(1):1-10 | DOI: 10.1007/s11099-018-0796-6