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Adherent macrofouling in marine environments caused complex corrosion of steel surfaces, resulting in localized corrosion at the oyster/steel interface and uniform corrosion at the ascidian/steel interface. Sulfate-reducing bacteria (SRB) have been implicated in the microbiologically influenced corrosion (MIC) process at macrofouling-covered interfaces. To better understand the role of marine biofilms as key mediators in the MIC process, metagenomic techniques were used to study microbial communities and their response to macrofouling's coverage. Compared to ascidians, the formed local anaerobic zone at oyster/steel interface stimulated the growth of SRBs, leading to higher FeS content and severe localized corrosion. SRB Desulfovibrio and Desulfobulbus, along with the SRB-related functional gene dsr, were found to increase, while oxygen-related function genes coxC, ccoN, ccoO, ccoP, and ccoQ decreased. In contrast, steel surfaces without macrofouling coverage had the richest microbial communities, yet experienced less severe MIC, suggesting no direct connection between microbial abundance/diversity and steel corrosion promotion. [ABSTRACT FROM AUTHOR]

The nuclear factor-κB (NF-κB) signaling pathway regulates specific immunological responses and controls a wide range of physiological processes. NF-κB inhibitor alpha (IKBA) is an NF-κB inhibitory mediator in the cytoplasm that modulates the nuclear translocation and DNA binding activities of NF-κB proteins. However, whether the upstream cascade of the canonical NF-κB signaling pathway has physiological roles independent of IKBA-mediated transcriptional activation remains unclear. Herein we investigated the function of IKBA in mature sperm in which transcriptional and translational events do not occur. IKBA was highly expressed in human sperm. The repression of IKBA phosphorylation by its inhibitor Bay117082 markedly enhanced sperm motility. On the contrary, lipopolysaccharide-stimulated IKBA phosphorylation significantly decreased sperm motility. Nevertheless, Bay117082 treatment did not affect the motility of IKBA-knockout sperm. Further, untargeted metabolomic analysis and pharmacological blocking assays revealed that the Bay117082-induced increase in sperm motility was attributable to fatty acid β-oxidation (FAO) enhancement. In addition, we found that IKBA phosphorylation inhibition resulted in a significant reduction of acetyl-CoA carboxylase levels in the FAO metabolic pathway. Our findings indicate that IKBA-mediated signaling orchestrates sperm motility program and improves our understanding of transcription-independent NF-κB signaling pathway in cells. NF-κB inhibitor alpha (IKBA) signaling in mature sperm drives sperm motility and controls fatty acid b-oxidation metabolism. [ABSTRACT FROM AUTHOR]

High-strength steels are widely used in marine engineering; however, they suffer from the risks of corrosion, hydrogen permeation, and stress corrosion cracking (SCC) in wet–dry cyclic marine environments. In this study, the corrosion, hydrogen permeation, and SCC behaviours of AISI 4135 steel in the tidal zone were investigated using electrochemical corrosion, electrochemical hydrogen permeation, and slow strain rate tests, respectively, via field exposure. The results showed that the AISI 4135 steel sample placed at the high tide level had high SCC susceptibility because of severe pitting corrosion and hydrogen permeation, whereas the steel samples placed at the middle and low tide levels had low SCC susceptibilities. The dry/wet time ratio was crucial in determining the SCC behaviour and mechanism of the steel in the tidal zone. With increasing time ratio, the SCC mechanism changed from micro-void coalescence control to localised anodic dissolution and hydrogen embrittlement in tandem. [ABSTRACT FROM AUTHOR]

Although the potential corrosive microbial communities of the refined oil pipelines can cause pipeline failure which directly threatens on soil and water environment, few studies have been published in this field. Therefore, the long-distance on-site internal corrosion detection and high-throughput sequencing techniques were employed in this study to investigate the distribution shifts of the corrosive microbial communities on the inner wall of a refined oil pipeline and its impact on the internal corrosion. The microorganisms colonizing on the inner wall of the pipeline showed significant distribution differences between the axial direction of the relative elevation and radial direction of the cross-section. On the inner wall, the high diversity and the abundance of the corrosive microbial communities induced serious microbiologically influenced corrosion (MIC), while the chemical corrosion and the synergy of the corrosive microbial communities accelerated the internal corrosion of the refined oil pipeline. A corrosion zone model has been proposed, which divides the pipeline cross-section into the sediment, the water–oil interface, the gas-oil interface, and the oil fully immersed zones. Therefore, the relationships between the environment, corrosion degree, and distribution characteristics of the corrosive microbial communities in the pipeline were analyzed. This research exhibited the importance of the distribution characteristics of the corrosive microorganisms on the inner wall of the refined oil pipelines. Its internal corrosion behavior was accurately explored, while providing a basis for controlling the corrosive microbial communities. [ABSTRACT FROM AUTHOR]

Background: The introduction of broadleaved tree species in monoculture larch plantations to establish mixed plantations is a feasible way to improve soil properties. However, our understanding of how mixed plantations of larch and broadleaved tree species affect soil properties, particularly microbial community structures and functions, remains limited. We compared three paired monoculture larch (Larix gmelinii) and mixed [L. gmelinii–Fraxinus mandshurica (a dominant broadleaved species)] plantations to investigate the effect of a larch–broadleaved tree species combination on the carbon (C) and nitrogen (N) content, abundance and composition of microbial communities, and enzyme activities associated with litter and soil. Results: The bacterial abundance in the litter, soil N availability, pH and electronic conductivity were significantly higher in the mixed-species plantation in comparison with those of the monoculture plantation. However, in the litter of mixed-species plantation, the relative levels of Agaricomycetes fungi were lower than those of the monoculture plantation, indicating that soil fungal communities were affected more than bacterial communities. In contrast, soil in the mixed-species plantation showed increased exoglucanase and N-acetyl-β-glucosaminidase activities. However, the C and N levels, δ13C and δ15N values, and fungal abundance in litter and soil were not significantly different between the monoculture and mixed-species plantations. Conclusions: Our findings suggest that fungal community compositions and enzyme activities are sensitive to the introduction of broadleaved tree species into larch plantations. Thus, these parameters can be used as important indicators to evaluate the effects of tree species selection on soil restoration. [ABSTRACT FROM AUTHOR]

Corrosion had aroused extensive concern and attention because it was an unavoidable problem for marine equipment and facilities in service. However, the current status and development trend of marine environment corrosion research had seldom been systematically studied. Therefore, it was encouraged to use bibliometrics and information visualization analysis methods to conduct bibliometric analysis of related publications in the field of marine environment corrosion based on HistCite, CiteSpace, and VOSviewer software programs. Compared with the traditional comments of researchers in this field, this research provided a direction for the development of quantitative analysis and visualization of marine environment corrosion on a large scale. The results showed that the overall focus of research in the field of marine environment corrosion continued to increase from 1900 to 2019. China had the highest publication productivity, the USA had the highest h-index value and the second highest average citations per item value, Materials Science was the most popular subject category, Corrosion Science was the main journal and Melchers RE was the author with the most output contributions. This research also exhibited four hot spots in this field. In addition, this work could help new researchers to find research directions and identify research trends and frontiers in the field of marine environment corrosion by tracing the research hotspots of topic categories, countries, institutions, journals, authors, and publications in recent years. [ABSTRACT FROM AUTHOR]