The isomeric composition of retinal was measured in a number of bacteriorhodopsin (bR) mutants (D85N, D212N, R82A, Y185F, and D115N) under various conditions, using a rapid retinal extraction technique followed by HPLC analysis. Besides the 13-cis and the all-trans retinal isomers observed in wild type (wt) bR under physiological conditions, the 1 1-cis and 9-cis retinal isomers were observed in variable but minor amounts in the bR mutants. In addition, the values of the equilibrium constant at two temperatures and the enthalpy change for the all-trans to 13-cis isomerization process in the dark-adapted state of D212N, DMN, deionized blue bR, and wt bR were determined. We find that perturbation of the retinal cavity (pocket) by residue replacement changes the relative thermal stability of the different retinal isomers, allowing for thermaland/or photoisomenzation of the retinal chromophore along C9-Cl0 and C1 1 -C12 bonds to moderately compete with the isomerization around the C I~-C I~ bond. The bR mutants expressed in Halobacterium salinarium studied in the present work showed normal 13-cis to all-trans light adaptation, in contrast with abnormal all-trans to 13-cis light adaptation observed for D212E, D212A, and D212N expressed in Escherichia coli, suggesting an influence of the purple membrane lattice and/or the lipids on the stability of the different retinal isomers within the protein.

The end-Permian mass extinction was followed by the formation of an enigmatic rock layer with a distinctive macroscopic spotted or dendroid fabric. This deposit has been interpreted as microbial reef rock, digitate dendrolite, digital thrombolite, dendritic thrombolite, or bacterial deposits. Agreement has been reached in considering them as microbialites, but not in their formation. This study has revealed that the spotted and dendroid microbialites were composed of numerous fossil casts formed by the planktic cyanobacterium, Microcystis, a coccoid genus that at the present-day commonly forms blooms in modern lakes, rivers, and reservoirs. The abundance of the fossils and the diagenesis they experienced has determined the macroscopic fabric: where they abundant, the rock appears as dendroid, otherwise, it appears as spotted. The ancient Microcystis bloom might produce toxin to kill other metazoans, and be responsible for the oceanic anoxia that has puzzled so many researchers for so many years.

A novel multiply synergetic Si@rGO/g-C3N4 as an ultra-long-life anode material for lithium-ion batteries was synthesized successfully via stable interface bonding.

When used for agricultural production, karst mountainous areas are susceptible to soil degradation due to the effects of soluble rocks and the climate. To mitigate the risk, the Grain for Green Project, a sizable initiative, was commenced to transition cultivated land away from agricultural use. This conversion of cultivated land to non-agricultural land has been significant. The study area considered in this research included four small towns in southwest China in karst mountainous areas with various morphologies. The investigation of the non-agriculturalization of cultivated land in the four sample areas revealed that the non-agriculturalization rate of cultivated land as a result of the Grain for Green Project has reached between 21.36% and 51.43% each decade. Thus, the Grain for Green Project has been advantageous for lowering the landscape ecological risk. Furthermore, because an increasing number of agricultural production materials have been introduced to the cultivated land, the conversion from cultivated land to non-agricultural land has not caused a staple food crisis on the national scale. However, it is impossible to observe all the potential drawbacks of the non-agriculturalization of cultivated land from satellite photos alone, and further social data collection is required. The findings of this study can offer precise information for policymaking in relation to the protection of rural cultivated land and rural spatial optimization in karst mountainous areas.