Optical Feedback Loop Involving Dinoflagellate Symbiont and Scleractinian Host Drives Colorful Coral Bleaching

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Iron-sulfur centers in the photosynthetic reaction center complex fromChlorobium vibrioforme. Differences from and similarities to the iron-sulfur centers in Photosystem I

The photosynthetic reaction center complex from the green sulfur bacteriumChlorobium vibrioforme has been isolated under anaerobic conditions. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis reveals polypeptides with apparent molecular masses of 80, 40, 30, 18, 15, and 9 kDa. The 80- and 18-kDa polypeptides are identified as the reaction center polypeptide and the secondary donor cytochromec ₅₅₁ encoded by thepscA andpscC genes, respectively. N-terminal amino acid sequences identify the 40-kDa polypeptide as the bacteriochlorophylla-protein of the baseplate (the Fenna-Matthews-Olson protein) and the 30-kDa polypeptide as the putative 2[4Fe-4S] protein encoded bypscB. Electron paramagnetic resonance (EPR) analysis shows the presence of an iron-sulfur cluster which is irreversibly photoreduced at 9K. Photoaccumulation at higher temperature shows the presence of an additional photoreduced cluster. The EPR spectra of the two iron-sulfur clusters resemble those of F_A and F_B of Photosystem I, but also show significantly differentg-values, lineshapes, and temperature and power dependencies. We suggest that the two centers are designated Center I (with calculatedg-values of 2.085, 1.898, 1.841), and Center II (with calculatedg-values of 2.083, 1.941, 1.878). The data suggest that Centers I and II are bound to thepscB polypeptide.     

Green tea extracts as ultraviolet protectants for the beet armyworm,Spodoptera exigua,nucleopolyhedrovirus

The addition of a caffeinated green tea, Camellia sinensis L., filtrate (1%) to the nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hübner), provided almost complete protection following UVB irradiation (30 min) in laboratory tests. There were few differences in UV protection when extracts were prepared at 27 or at 90°C. Moreover, few differences in UV protection were demonstrated following infusion times of 5, 15, 30, and 60 min at 90°C. At a 1% concentration, decaffeinated and caffeinated green teas were equally effective as UV protectants. At lower concentrations (0.1, 0.01, and 0.001%) caffeinated green tea provided greater UV protection (UVB/UVB 30, 60 min). Virus/tea extracts (caffeinated), under field conditions at 1 and 5%, were ineffective as UV screens. At a 10% concentration, some UV protection was provided and UV protection further increased in a concentration-dependent manner.     

Treatment of carrots with spent green tea extract reduces the soft rot of Pectobacterium spp.

In the present study the antibacterial activity of spent green tea (SGT) was evaluated against Pectobacterium spp. causing soft rot incidence. Gas chromatography and mass spectroscopy (GC-MS) analysis reveal the presence of caffeine in the SGT extracts. Time kill assay revealed that SGT was able to kill Pectobacterium spp. at 18 h at 10 × MIC and at 24 h at 1 × MIC concentration. SGT led to the significant decrease in pectin lyase (PL), polygalcturonase (PG) and pectin methyl esterase activity in carrots challenge inoculated with Pectobacterium spp. SGT treated carrots recorded low degree of maceration, and relative electrolyte leakage (REL) values and also maintained high β carotene content, phenolic content and total antioxidant percentage. Based on the results of this study it could be concluded that SGT was able to offer protection to carrot against soft rot causing Pectobacterium spp. under post-harvest storage conditions.     

Green land: Multiple perspectives on green algal evolution and the earliest land plants

Green plants, broadly defined as green algae and the land plants (together, Viridiplantae), constitute the primary eukaryotic lineage that successfully colonized Earth's emergent landscape. Members of various clades of green plants have independently made the transition from fully aquatic to subaerial habitats many times throughout Earth's history. The transition, from unicells or simple filaments to complex multicellular plant bodies with functionally differentiated tissues and organs, was accompanied by innovations built upon a genetic and phenotypic toolkit that have served aquatic green phototrophs successfully for at least a billion years. These innovations opened an enormous array of new, drier places to live on the planet and resulted in a huge diversity of land plants that have dominated terrestrial ecosystems over the past 500 million years. This review examines the greening of the land from several perspectives, from paleontology to phylogenomics, to water stress responses and the genetic toolkit shared by green algae and plants, to the genomic evolution of the sporophyte generation. We summarize advances on disparate fronts in elucidating this important event in the evolution of the biosphere and the lacunae in our understanding of it. We present the process not as a step-by-step advancement from primitive green cells to an inevitable success of embryophytes, but rather as a process of adaptations and exaptations that allowed multiple clades of green plants, with various combinations of morphological and physiological terrestrialized traits, to become diverse and successful inhabitants of the land habitats of Earth.     

Freshwater ecosystems could become the biggest losers of the Paris Agreement

Securing access to energy for a growing population under the international commitment of reduction of greenhouse emissions requires increasing the contribution of renewable sources to the global share. Hydropower energy, which accounts for >80% of green energy, is experiencing a boom fostered by international investment mainly in developing countries. This boom could be further accelerated by the recent climate agreement reached in Paris. Despite its flexibility, hydropower production entails social, economic and ecological risks that need to be carefully considered before investing in the development of potentially thousands of planned hydropower projects worldwide. This is especially relevant given the weak or nonexistent legislation that regulates hydropower project approval and construction in many countries. I highlight the need for adequate policy to provide the Paris Agreement with new financial and planning mechanisms to avoid further and irreversible damage to freshwater ecosystem services and biodiversity.