Experimental and Field Constraints on the Role of Silica–Organic Complexation and Silica–Microbial Interactions during Sediment Diagenesis

2009 ◽  
pp. 119-127
Author(s):  
J. B. Fein
Keyword(s):  
Microbial Interactions ◽  
Organic Complexation ◽  
Sediment Diagenesis

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 CRISPR/Cas9 mutagenesis reveals a role for ABCB1 in gut immune responses to Vibrio diazotrophicus in sea urchin larvae

2021 ◽  
Vol 224 (7) ◽  
Author(s):  
Travis J. Fleming ◽  
Catherine S. Schrankel ◽  
Himanshu Vyas ◽  
Hannah D. Rosenblatt ◽  
Amro Hamdoun
Keyword(s):  
Immune Responses ◽  
Sea Urchin ◽  
Gene Editing ◽  
Opportunistic Pathogen ◽  
Microbial Interactions ◽  
Protective Mechanism ◽  
Ancestral Function ◽  
Microbial Environment ◽  
Invertebrate Larvae

ABSTRACT The ABC transporter ABCB1 plays an important role in the disposition of xenobiotics. Embryos of most species express high levels of this transporter in early development as a protective mechanism, but its native substrates are not known. Here, we used larvae of the sea urchin Strongylocentrotus purpuratus to characterize the early life expression and role of Sp-ABCB1a, a homolog of ABCB1. The results indicate that while Sp-ABCB1a is initially expressed ubiquitously, it becomes enriched in the developing gut. Using optimized CRISPR/Cas9 gene editing methods to achieve high editing efficiency in the F0 generation, we generated ABCB1a crispant embryos with significantly reduced transporter efflux activity. When infected with the opportunistic pathogen Vibrio diazotrophicus, Sp-ABCB1a crispant larvae demonstrated significantly stronger gut inflammation, immunocyte migration and cytokine Sp-IL-17 induction, as compared with infected control larvae. The results suggest an ancestral function of ABCB1 in host–microbial interactions, with implications for the survival of invertebrate larvae in the marine microbial environment.

scholarly journals Micro-aggregation of a pristine grassland soil selects for bacterial and fungal communities and changes in nitrogen cycling potentials

2021 ◽  
Author(s):  
Christoph Keuschnig ◽  
Jean Martins ◽  
Aline Navel ◽  
Pascal Simonet ◽  
Catherine Larose
Keyword(s):  
Particle Size ◽  
Nitrogen Cycling ◽  
Bacterial Communities ◽  
Soil Microbial Communities ◽  
Microbial Interactions ◽  
Fungal Communities ◽  
Supernatant Fraction ◽  
Soil Microbial ◽  
Microbial Analysis

Microbial analysis at the micro scale of soil is essential to the overall understanding of microbial organization and interactions, and necessary for a better understanding of soil ecosystem functioning. While bacterial communities have been extensively described, little is known about the organization of fungal communities as well as functional potentials at scales relevant to microbial interactions. Fungal and bacterial communities and changes in nitrogen cycling potentials in the pristine Rothamsted Park Grass soil (bulk soil) as well as in its particle size sub-fractions (PSFs; > 250 µm, 250-63 µm, 63-20 µm, 20-2 µm, < 2 µm and supernatant) were studied. The potential for nitrogen reduction was found elevated in bigger aggregates. The relative abundance of Basidiomycota deceased with decreasing particle size, Ascomycota showed an increase and Mucoromycota became more prominent in particles less than 20 µm. Bacterial community structures changed below 20 µm at the scale where microbes operate.Strikingly, only members of two bacterial and one fungal phyla (Proteobacteria, Bacteroidota and Ascomycota, respectively) were washed-off the soil during fractionation and accumulated in the supernatant fraction where most of the detected bacterial genera (e.g., Pseudomonas, Massilia, Mucilaginibacter, Edaphobaculum, Duganella, Janthinobacterium and Variovorax) were previously associated with exopolysaccharide production and biofilm formation.Overall, the applied method shows potential to study soil microbial communities at micro scales which might be useful in studies focusing on the role of specific fungal taxa in soil structure formation as well as research on how and by whom biofilm-like structures are distributed and organized in soil.

scholarly journals Dynamic age-associated changes and their driver microbes in healthy gut microbiota of captive crab-eating macaques

2020 ◽  
Author(s):  
Zhi-Yuan Wei ◽  
Jun-Hua Rao ◽  
Ming-Tian Tang ◽  
Guo-An Zhao ◽  
Qi-Chun Li ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Alpha Diversity ◽  
Active Role ◽  
Antibiotic Use ◽  
Microbial Interactions ◽  
Topology Analysis ◽  
Show Evidence ◽  
Gut Mucosa ◽  
Metabolite Synthesis

Abstract Background: Previous population studies have indicated age-associated changes in the gut microbiota. However, the actual age effects on microbiota are inevitably confounded by varying environmental factors such as diets and antibiotic use in the populations. Captive crab-eating macaques reared in a well-controlled environment can provide a useful model to recapitulate dynamic age-associated changes in the healthy primate gut microbiota.Results: We show evidence supporting lifelong age-associated changes in the healthy gut microbiota of captive macaques. The Firmicutes to Bacteroidetes ratio and beta diversity but not alpha diversity changed significantly with age. The most significantly age-associated genera were mainly composed of commensals, such as Faecalibacterium . Unexpectedly, a subset of the age-associated microbes were suspicious pathogens such as Helicobacter and Campylobacter , which were enriched in infant macaques, and possibly associated with gut mucosa development. These age-associated microbes were main contributors to the gut microbiota networks. Importantly, topology analysis showed that connectivity of these networks changed with age, and its rapid decrease in elderly macaques might indicate altered microbial interactions associated with host aging. Prevotella 9 , one of the most abundant age-associated genera, was the driver responsible for the gut microbiota maturation from infants to young adults. In adults, Rikenellaceae RC9 gut group and Megasphaera were two key drivers that continuously played an active role in driving microbial community changes of across different stages of adulthood. We also showed evidence of age-associated changes in gut microbial phenotypes and functions, in particular pathways of immunomodulatory metabolite synthesis, and metabolism of lipids and carbohydrates. The driver microbes were key players involved in these functions.Conclusions: Our current study in captive macaques demonstrate evident age-associated changes during the lifelong process of healthy gut microbiota development. The enrichment of suspicious pathogens in healthy infant macaques might indicate the importance of appropriate exposure to these microbes for the developing immune system. The current study provides new insights into the pivotal role of driver microbes and microbial interactions in gut microbiota, and further underlines the importance of network analysis in microbiome studies. Our findings also provide a baseline for better understanding of disease-related changes in the primate gut microbiota.

scholarly journals The Yin and Yang ofStreptococcusLung Infections in Cystic Fibrosis: a Model for Studying Polymicrobial Interactions

2019 ◽  
Vol 201 (11) ◽  
Author(s):  
Jessie E. Scott ◽  
George A. O’Toole
Keyword(s):  
Cystic Fibrosis ◽  
Lung Disease ◽  
Microbial Interactions ◽  
Oral Streptococci ◽  
Content Type ◽  
Lung Microbiome ◽  
Oral Microflora ◽  
Streptococcus Milleri ◽  
Yin And Yang

ABSTRACTThe streptococci are increasingly recognized as a core component of the cystic fibrosis (CF) lung microbiome, yet the role that they play in CF lung disease is unclear. The presence of theStreptococcus millerigroup (SMG; also known as the anginosus group streptococci [AGS]) correlates with exacerbation when these microbes are the predominant species in the lung. In contrast, microbiome studies have indicated that an increased relative abundance of streptococci in the lung, including members of the oral microflora, correlates with impacts on lung disease less severe than those caused by other CF-associated microflora, indicating a complex role for this genus in the context of CF. Recent findings suggest that streptococci in the CF lung microenvironment may influence the growth and/or virulence of other CF pathogens, as evidenced by increased virulence factor production byPseudomonas aeruginosawhen grown in coculture with oral streptococci. Conversely, the presence ofP. aeruginosacan enhance the growth of streptococci, including members of the SMG, a phenomenon that could be exacerbated by the fact that streptococci are not susceptible to some of the frontline antibiotics used to treatP. aeruginosainfections. Collectively, these studies indicate the necessity for further investigation into the role of streptococci in the CF airway to determine how these microbes, alone or via interactions with other CF-associated pathogens, might influence CF lung disease, for better or for worse. We also propose that the interactions of streptococci with other CF pathogens is an ideal model to study clinically relevant microbial interactions.

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