Modularity in Protein Evolution: Modular Organization and De Novo Domain Evolution in Mollusk Metallothioneins

Metallothioneins (MTs) are proteins devoted to the control of metal homeostasis and detoxification, and therefore, MTs have been crucial for the adaptation of the living beings to variable situations of metal bioavailability. The evolution of MTs is, however, not yet fully understood, and to provide new insights into it, we have investigated the MTs in the diverse classes of Mollusks. We have shown that most molluskan MTs are bimodular proteins that combine six domains—α, β1, β2, β3, γ, and δ—in a lineage-specific manner. We have functionally characterized the Neritimorpha β₃β₁ and the Patellogastropoda γβ₁ MTs, demonstrating the metal-binding capacity of the new γ domain. Our results have revealed a modular organization of mollusk MT, whose evolution has been impacted by duplication, loss, and de novo emergence of domains. MTs represent a paradigmatic example of modular evolution probably driven by the structural and functional requirements of metal binding.     

Probing the sORF-Encoded Peptides of Deinococcus radiodurans in Response to Extreme Stress

Organisms have developed different mechanisms to respond to stresses. However, the roles of small ORF–encoded peptides (SEPs) in these regulatory systems remain elusive, which is partially because of the lack of comprehensive knowledge regarding these biomolecules. We chose the extremophile Deinococcus radiodurans R1 as a model species and conducted large-scale profiling of the SEPs related to the stress response. The integrated workflow consisting of multiple omics approaches for SEP identification was streamlined, and an SEPome of D. radiodurans containing 109 novel and high-confidence SEPs was drafted. Forty-four percent of these SEPs were predicted to function as antimicrobial peptides. Quantitative peptidomics analysis indicated that the expression of SEP068184 was upregulated upon oxidative treatment and gamma irradiation of the bacteria. SEP068184 was conserved in Deinococcus and exhibited negative regulation of oxidative stress resistance in a comparative phenotypic assay of its mutants. Further quantitative and interactive proteomics analyses suggested that SEP068184 might function through metabolic pathways and interact with cytoplasmic proteins. Collectively, our findings demonstrate that SEPs are involved in the regulation of oxidative resistance, and the SEPome dataset provides a rich resource for research on the molecular mechanisms of the response to extreme stress in organisms.     

Dichlorophenyl dimethylurea (DCMU) induced increase in chlorophyll a fluorescence intensity – An index of photosynthetic oxygen evolution in leaves, chloroplasts and algae

Dichlorophenyl dimethylurea (DCMU) treatment in photosynthetic samples resulted in an increase in the level of steady state chlorophyll a fluorescence at room temperature which was directly proportional to the photosynthetic efficiency. The applicability of this method for the rapid determination of the efficiency of oxygen evolution in leaves, algae, mesophyll cells and chloroplasts has been investigated. Especially reliable values with less than 5% error were obtained if the fluorescence measurements were made under low excitation intensities with a sample chlorophyll concentration below 1.0 μg/ml.     

Innate-immune responses of tilapia (Oreochromis mossambicus) exposure to acute cold stress

In this present study, Oreochromis mossambicus tilapia were transferred to cold water at 12°C for various time intervals (1, 4, 8, 24, and 48 hr) and its innate immune response was analyzed by studying cellular and humoral parameters. In vivo, alternative complement pathway activity in blood plasma was rapidly increased at 1 hr of cold water (12°C) exposure. Lysozyme activity and cortisol levels of plasma were increased at 4 and 1 hr, respectively. Surprisingly, only plasma cortisol levels remained unchanged through 24 hr of cold water transfer. Phagocytic ability, phagocytic capacity, and respiratory burst (RB) activity of head kidney (HK) leukocytes and splenocytes showed no any significant changes. In peripheral blood leukocytes, phagocytic capacity, and RB activity were increased at 24 hr of cold water exposure. The expressions of genes involved innate immunity in splenocytes and HK leukocytes of tilapia cold water exposure were analyzed, messenger RNA (mRNA) expressions of HSP70, HSP90, and immunoglobulin M failed to change upon exposure to cold stress. Major histocompatibility complex-I and II mRNAs were significantly increased in tilapia splenocytes at 1 hr of cold water transferred. Whereas myxovirus (Mx) expression was increased in splenocytes and HK leukocytes of tilapia after 1 hr of cold water exposed. Our result reveals that the exposure of tilapia to acute cold stress condition significantly enhances plasma acid phosphatase activity and both phagocytic capacity and RB activity. Furthermore, cold stress significantly stimulates Mx gene expression in splenocytes and HK leukocytes.     

Urban road traffic scale analysis from the perspective of atmospheric environmental indicators in Tianjin,China

In order to investigate the largest motor vehicle ownership load within the scope of a city with atmospheric environmental indicators as constraint, this article estimates traffic atmospheric environmental capacity (TAEC) and carrying capacity (TAECC) in Tianjin using the A-value method recommended by the Chinese national standard. Our results indicate that NO_X carrying capacity is a key restraining factor of TAEC. According to the current vehicle emission levels per year and air quality standard, Tianjin can accommodate 4.21 million vehicles. Classified by the vehicle type, heavy trucks and large-sized passenger cars are identified as the most important restrictive factors of TAECC. Then we analyze change of TAECC and TAECC’s service life under the circumstances of clean vehicle strategy and mobility management strategy. Clean vehicles strategy represented by the elimination of heavy-polluting vehicles can reduce emissions of vehicles so that it can rapidly enhance the TAECC in the short term. Mobility management strategy represented by the car purchase restriction, which reduces total motor vehicle travel, is indispensable for improvement of TAECC in the long term. On the whole, the clean vehicles strategy and mobility management strategy should be implemented gradually.     

Survivability and post‐diapause fitness in a scolytid beetle as a function of overwintering developmental stage and the implications for population dynamics

1. It has recently been suggested that expected increases in temperature might lead to an additional generation per season in bark beetles. Thus, populations would grow more rapidly. However, an additional but not fully developed generation could lead to high winter mortality in the pre‐imaginal stages. 2. Winter survivability and post‐diapause fitness as a function of the overwintering developmental stage of the spruce bark beetle Ips typographus L. were studied along an altitudinal cline. Fitness was tested in terms of weight, lipid content and flight capacity. 3. Mortality was significantly lower and emergence per brood system significantly higher for fully developed adults that entered overwintering than for larvae, pupae or callow adults. 4. Post‐diapause fitness in terms of dry weight and flight capacity was significantly higher in individuals that completed development before winter, and lipid contents also showed a trend for being higher in those individuals. 5. In conclusion, in a scenario where effective temperature sums are not adequate for the complete development of an additional generation, models may overestimate population growth by neglecting increased mortality and reduced post‐diapause fitness. The results highlight the importance of considering life‐history traits and indirect effects in addition to abiotic factors such as temperature when modelling population dynamics.