scholarly journals The Mechanism of Microbial-Ferromanganese Nodule Interaction and the Contribution of Biomineralization to the Formation of Oceanic Ferromanganese Nodules

2021 ◽  
Vol 9 (6) ◽  
pp. 1247
Author(s):  
Jing Lyu ◽  
Xinke Yu ◽  
Mingyu Jiang ◽  
Wenrui Cao ◽  
Gaowa Saren ◽  
...  
Keyword(s):  
Nucleation Site ◽  
Major Elements ◽  
Genetic Mechanism ◽  
Nodule Formation ◽  
Ferromanganese Nodule ◽  
Marine Microorganisms ◽  
Mineral Precipitation ◽  
Ferromanganese Nodules ◽  
Mineral Particles

Ferromanganese nodules are an important mineral resource in the seafloor; however, the genetic mechanism is still unknown. The biomineralization of microorganisms appears to promote ferromanganese nodule formation. To investigate the possible mechanism of microbial–ferromanganese nodule interaction, to test the possibility of marine microorganisms as deposition template for ferromanganese nodules minerals, the interactions between Jeotgalibacillus campisalis strain CW126-A03 and ferromanganese nodules were studied. The results showed that strain CW126-A03 increased ion concentrations of Fe, Mn, and other metal elements in solutions at first. Then, metal ions were accumulated on the cells’ surface and formed ultra-micro sized mineral particles, even crystalline minerals. Strain CW126-A03 appeared to release major elements in ferromanganese nodules, and the cell surface may be a nucleation site for mineral precipitation. This finding highlights the potentially important role of biologically induced mineralization (BIM) in ferromanganese nodule formation. This BIM hypothesis provides another perspective for understanding ferromanganese nodules’ genetic mechanism, indicating the potential of microorganisms in nodule formation.

Nitrate reductases and hemoglobins control nitrogen-fixing symbiosis by regulating nitric oxide accumulation

2020 ◽  
Author(s):  
Antoine Berger ◽  
Alexandre Boscari ◽  
Alain Puppo ◽  
Renaud Brouquisse
Keyword(s):  
Nitric Oxide ◽  
Defense Responses ◽  
Nodule Formation ◽  
No Production ◽  
Degradation Pathways ◽  
Atmospheric Nitrogen ◽  
Metabolic Intermediate ◽  
Hypoxic Environment ◽  
Nitrate Reductases

Abstract The interaction between legumes and rhizobia leads to the establishment of a symbiotic relationship between plant and bacteria. This is characterized by the formation of a new organ, the nodule, which facilitates the fixation of atmospheric nitrogen (N2) by nitrogenase through the creation of a hypoxic environment. Nitric oxide (NO) accumulates at each stage of the symbiotic process. NO is involved in defense responses, nodule organogenesis and development, nitrogen fixation metabolism, and senescence induction. During symbiosis, either successively or simultaneously, NO regulates gene expression, modulates enzyme activities, and acts as a metabolic intermediate in energy regeneration processes via phytoglobin-NO respiration and the bacterial denitrification pathway. Due to the transition from normoxia to hypoxia during nodule formation, and the progressive presence of the bacterial partner in the growing nodules, NO production and degradation pathways change during the symbiotic process. This review analyzes the different source and degradation pathways of NO, and highlights the role of nitrate reductases and hemoproteins of both the plant and bacterial partners in the control of NO accumulation.

Creative Tourist Experience

2017 ◽  
pp. 278-298
Author(s):  
Amitabh Upadhya ◽  
Mohit Vij
Keyword(s):  
Qualitative Methodology ◽  
Major Elements ◽  
Core Theme ◽  
The Core ◽  
Tourist Experience ◽  
Destination Management Organizations

The chapter explores the role and importance of Destination Management Organizations in managing the delivery of creative tourist experience. The study is divided in two parts whereby the first part adopts a qualitative methodology of exploration in regard to Destination Management Organizations and Creative Tourist Experiences while the second part is a case study of the tourism organizations of the UAE. The role of creativity in managing the total tourist experience is the core theme of the study. The study finds that co-creation of tourist experiences have a lasting memory value. Creative tourist experience can be achieved in the creative-theatre by a combination of designed aesthetics, choreographed activities and co-created souvenirs as the major elements.

scholarly journals The Role of Long Period Stacking Ordered Phase in Dynamic Recrystallization of a Mg–Gd–Y–Zn–Zr Alloy during Multi-Directional Forging Process

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3290
Author(s):  
Huiling Liu ◽  
Yingze Meng ◽  
Huisheng Yu ◽  
Wenlong Xu ◽  
Siyang Zhang ◽  
...  
Keyword(s):  
Dynamic Recrystallization ◽  
Nucleation Site ◽  
Nucleation Mechanism ◽  
Forging Process ◽  
Lpso Phase ◽  
Long Period ◽  
Texture Intensity ◽  
Uniform Microstructure ◽  
Zr Alloy

The Mg–Gd–Y–Zn–Zr alloy containing a long period stacking ordered (LPSO) phase was subjected to multi-pass deformation by means of a multi-directional forging process, and the microstructure evolution and the influence of the LPSO phase on its dynamic recrystallization (DRX) were studied. The results showed that multi-directional forging can effectively refine the grain with the DRX fraction increased, and DRXed grains lead to the decrease of the texture intensity, which can significantly improve the mechanical properties of the alloy. The different morphologies of the LPSO phase have different degrees of promotion relative to DRX behavior. The lamellar LPSO phase with kinks promoted dislocation plugging, where there could be a potential nucleation site for DRX grains. The fragmented lamellar LPSO phase promoted the DRX process through the particle-stimulated nucleation mechanism, and the block-shaped phase was more prone to stress concentration, which promoted DRX. These effects resulted in continuous grain refinement and a more uniform microstructure.

Managing Corporate E-Mail Systems

2011 ◽  
pp. 254-281
Author(s):  
Aidan Duane ◽  
Patrick Finnegan
Keyword(s):  
Major Elements ◽  
Electronic Business ◽  
Monitoring And Control ◽  
Negative Effects ◽  
Multiple Case ◽  
And Control ◽  
Mail System ◽  
E Mail

As the criticality of e-mail for electronic business activity increases, adhoc e-mail implementation, prolonged management neglect and user abuse of e-mail systems have generated negative effects. However, management’s ability to rectify problems with e-mail systems is hindered by our understanding of its organisational use. Research on e-mail systems is often dated and based on quantitative methodologies that cannot explain the interaction between various controls in organisational settings. Updating our understanding of the organisational aspects of e-mail systems utilizing qualitative methods is necessary. This chapter presents a multiple case study investigation of e-mail system monitoring and control. The study examines the interaction between key elements of e-mail control identified by previous researchers and considers the role of such controls at various implementation phases. The findings reveal eight major elements to be particularly important in monitoring and controlling e-mail systems within the organisations studied. These are: (1) form a cross-functional e-mail system management team; (2) implement and regularly update e-mail management software; (3) formulate a detailed and legally sound e-mail policy; (4) engage in structured e-mail system training; (5) create and maintain ongoing awareness of e-mail policy; (6) engage in a process of hybrid feedback and control-based e-mail monitoring; (7) firmly enforce discipline in accordance with the e-mail policy; and (8) conduct regular reviews and updates of the e-mail management programme.

In situ synthesis of hierarchical nitrogen-doped MoS2 microsphere with an excellent visible light-driven photocatalytic nitrogen fixation ability

2020 ◽  
Vol 13 (05) ◽  
pp. 2051031
Author(s):  
Abulikemu Abulizi ◽  
Hujiabudula Maimaitizi ◽  
Dilinuer Talifu ◽  
Yalkunjan Tursun
Keyword(s):  
Visible Light ◽  
High Performance ◽  
Nucleation Site ◽  
Active Species ◽  
Nitrogen Doped ◽  
Photogenerated Electrons ◽  
The Hierarchical Structure ◽  
Visible Light Driven

A photocatalyst of high-performance hierarchical nitrogen-doped MoS2 (N-MoS2) microsphere was fabricated by an in situ hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB). The as-prepared N-MoS2 microsphere was self-assembled by extremely thin interleaving petals, where CTAB acts as a nucleation site for the formation of the interleaving petals due to the strong interaction between CTA+ and [Formula: see text]. N-MoS2 showed higher N2 fixation ability (101.2 [Formula: see text] mol/g(cat)h) than the non-doped MoS2 under the visible light irradiation, and the improved photocatalytic activity could be ascribed to that the doped N narrows the band gap, and the surface reflecting and scattering effect caused by the hierarchical structure enhance the light adsorption. The trapping experiment of active species was also investigated to evaluate the role of photogenerated electrons in the photocatalytic reaction process. Meanwhile, the possible mechanism for the formation and excellent photocatalytic performance of N-MoS2 microsphere were also presented.

scholarly journals Marine Microbial Assemblages on Microplastics: Diversity, Adaptation, and Role in Degradation

2020 ◽  
Vol 12 (1) ◽  
pp. 209-232 ◽  
Author(s):  
Sonja Oberbeckmann ◽  
Matthias Labrenz
Keyword(s):  
Pathogenic Bacteria ◽  
Life Forms ◽  
Microbial Interactions ◽  
The Other ◽  
Human Society ◽  
Marine Microorganisms ◽  
Microbial Adaptation ◽  
Artificial Surfaces ◽  
Plastic Degradation

We have known for more than 45 years that microplastics in the ocean are carriers of microbially dominated assemblages. However, only recently has the role of microbial interactions with microplastics in marine ecosystems been investigated in detail. Research in this field has focused on three main areas: ( a) the establishment of plastic-specific biofilms (the so-called plastisphere); ( b) enrichment of pathogenic bacteria, particularly members of the genus Vibrio, coupled to a vector function of microplastics; and ( c) the microbial degradation of microplastics in the marine environment. Nevertheless, the relationships between marine microorganisms and microplastics remain unclear. In this review, we deduce from the current literature, new comparative analyses, and considerations of microbial adaptation concerning plastic degradation that interactions between microorganisms and microplastic particles should have rather limited effects on the ocean ecosystems. The majority of microorganisms growing on microplastics seem to belong to opportunistic colonists that do not distinguish between natural and artificial surfaces. Thus, microplastics do not pose a higher risk than natural particles to higher life forms by potentially harboring pathogenic bacteria. On the other hand, microplastics in the ocean represent recalcitrant substances for microorganisms that are insufficient to support prokaryotic metabolism and will probably not be microbially degraded in any period of time relevant to human society. Because we cannot remove microplastics from the ocean, proactive action regarding research on plastic alternatives and strategies to prevent plastic entering the environment should be taken promptly.

scholarly journals Co-Inoculation of Bacillus velezensis Strain S141 and Bradyrhizobium Strains Promotes Nodule Growth and Nitrogen Fixation

2020 ◽  
Vol 8 (5) ◽  
pp. 678
Author(s):  
Surachat Sibponkrung ◽  
Takahiko Kondo ◽  
Kosei Tanaka ◽  
Panlada Tittabutr ◽  
Nantakorn Boonkerd ◽  
...  
Keyword(s):  
N2 Fixation ◽  
Growth Promotion ◽  
Nodule Formation ◽  
Bacillus Velezensis ◽  
Cytokinin Biosynthesis ◽  
Large Size ◽  
Other Substances ◽  
Glycine Max L ◽  
Iaa Biosynthesis

The objective of this research was to evaluate the PGPR effect on nodulation and nitrogen-fixing efficiency of soybean (Glycine max (L.) Merr.) by co-inoculation with Bradyrhizobium diazoefficiens USDA110. Co-inoculation of Bacillus velezensis S141 with USDA110 into soybean resulted in enhanced nodulation and N2-fixing efficiency by producing larger nodules. To understand the role of S141 on soybean and USDA110 symbiosis, putative genes related to IAA biosynthesis were disrupted, suggesting that co-inoculation of USDA110 with S141ΔyhcX reduces the number of large size nodules. It was revealed that yhcX may play a major role in IAA biosynthesis in S141 as well as provide a major impact on soybean growth promotion. The disruption of genes related to cytokinin biosynthesis and co-inoculation of USDA110 with S141ΔIPI reduced the number of very large size nodules, and it appears that IPI might play an important role in nodule size of soybean–Bradyrhizobium symbiosis. However, it was possible that not only IAA and cytokinin but also some other substances secreted from S141 facilitate Bradyrhizobium to trigger bigger nodule formation, resulting in enhanced N2-fixation. Therefore, the ability of S141 with Bradyrhizobium co-inoculation to enhance soybean N2-fixation strategy could be further developed for supreme soybean inoculants.

Transport of the river load from the Błądzikowski stream to the puck lagoon (southern Baltic Sea, Poland)

2013 ◽  
Vol 42 (2) ◽  
Author(s):  
Marta Damaszke ◽  
Ewa Szymczak
Keyword(s):  
Baltic Sea ◽  
Granulometric Composition ◽  
Surface Sediments ◽  
Suspended Load ◽  
Bed Load ◽  
Estuarine Area ◽  
Southern Baltic Sea ◽  
Mineral Particles ◽  
Sea Bed

AbstractThe main aim of this study was to determine the size of the load carried by the Błądzikowski Stream and discharged into the Puck Lagoon, and the role of the river load in the formation of the sea bed deposits at the stream mouth. The Błądzikowski Stream, with the length of only 10 km, discharges about 610 tons of sediment into the Puck Lagoon per year, including 89.8% (548 tons) of the bed load and 10.2% (62 tons) of the suspended load. The amount is 4.9% of the river load discharged into the Puck Lagoon. Mineral particles are more common in the composition of the river load and account for 94.6% of the suspended load and 98.7% of the bed load. It is mainly the bed load deposited in the estuarine area that creates a contemporary underwater accumulation form in the Puck Lagoon, which is corroborated by the granulometric composition of the channel and surface sediments; the suspended load is carried further into the Lagoon.

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