Representative sampling of natural biofilms: influence of substratum type on the bacterial and fungal communities structure

Much progress has been made in recent years towards the development of closed-loop foundry sand reclamation systems. However, virtually all work to date has determined the effectiveness of these systems to remove surface clay and metal oxide scales by a qualitative inspection of a representative sampling of sand particles. In this investigation, particles from a series of foundry sands were sized and chemically classified by a Lemont image analysis system (which was interfaced with an SEM and an X-ray energy dispersive spectrometer) in order to statistically document the effectiveness of a reclamation system developed by The Pangborn Company - a subsidiary of SOHIO.The following samples were submitted: unreclaimed sand; calcined sand; calcined & mechanically scrubbed sand and unused sand. Prior to analysis, each sample was sprinkled onto a carbon mount and coated with an evaporated film of carbon. A backscattered electron photomicrograph of a field of scale-covered particles is shown in Figure 1. Due to a large atomic number difference between sand particles and the carbon mount, the backscattered electron signal was used for image analysis since it had a uniform contrast over the shape of each particle.

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Experimentally altered rainfall regimes and host root traits affect grassland arbuscular mycorrhizal fungal communities

10.32942/osf.io/cu4jh ◽

2019 ◽

Author(s):

Coline Deveautour ◽

Suzanne Donn ◽

Sally Power ◽

Kirk Barnett ◽

Jeff Powell

Keyword(s):

Fungal Community ◽

Community Assembly ◽

Root Length ◽

Specific Root Length ◽

Root Traits ◽

Arbuscular Mycorrhizal ◽

Fungal Communities ◽

Rainfall Regime ◽

Precipitation Regimes ◽

Rainfall Regimes

Future climate scenarios predict changes in rainfall regimes. These changes are expected to affect plants via effects on the expression of root traits associated with water and nutrient uptake. Associated microorganisms may also respond to these new precipitation regimes, either directly in response to changes in the soil environment or indirectly in response to altered root trait expression. We characterised arbuscular mycorrhizal (AM) fungal communities in an Australian grassland exposed to experimentally altered rainfall regimes. We used Illumina sequencing to assess the responses of AM fungal communities associated with four plant species sampled in different watering treatments and evaluated the extent to which shifts were associated with changes in root traits. We observed that altered rainfall regimes affected the composition but not the richness of the AM fungal communities, and we found distinctive communities in the increased rainfall treatment. We found no evidence of altered rainfall regime effects via changes in host physiology because none of the studied traits were affected by changes in rainfall. However, specific root length was observed to correlate with AM fungal richness, while concentrations of phosphorus and calcium in root tissue and the proportion of root length allocated to fine roots were correlated to community composition. Our study provides evidence that climate change and its effects on rainfall may influence AM fungal community assembly, as do plant traits related to plant nutrition and water uptake. We did not find evidence that host responses to altered rainfall drive AM fungal community assembly in this grassland ecosystem.

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Temporal dynamics of mycorrhizal fungal communities and co-associations with grassland plant communities following experimental manipulation of rainfall

10.32942/osf.io/t82ug ◽

2019 ◽

Cited By ~ 1

Author(s):

Coline Deveautour ◽

Sally Power ◽

Kirk Barnett ◽

Raul Ochoa-Hueso ◽

Suzanne Donn ◽

...

Keyword(s):

Community Composition ◽

Plant Community ◽

Plant Communities ◽

Fungal Community ◽

Mycorrhizal Fungi ◽

Temporal Dynamics ◽

Arbuscular Mycorrhizal ◽

Fungal Communities ◽

Plant Responses ◽

Rainfall Regimes

Climate models project overall a reduction in rainfall amounts and shifts in the timing of rainfall events in mid-latitudes and sub-tropical dry regions, which threatens the productivity and diversity of grasslands. Arbuscular mycorrhizal fungi may help plants to cope with expected changes but may also be impacted by changing rainfall, either via the direct effects of low soil moisture on survival and function or indirectly via changes in the plant community. In an Australian mesic grassland (former pasture) system, we characterised plant and arbuscular mycorrhizal (AM) fungal communities every six months for nearly four years to two altered rainfall regimes: i) ambient, ii) rainfall reduced by 50% relative to ambient over the entire year and iii) total summer rainfall exclusion. Using Illumina sequencing, we assessed the response of AM fungal communities sampled from contrasting rainfall treatments and evaluated whether variation in AM fungal communities was associated with variation in plant community richness and composition. We found that rainfall reduction influenced the fungal communities, with the nature of the response depending on the type of manipulation, but that consistent results were only observed after more than two years of rainfall manipulation. We observed significant co-associations between plant and AM fungal communities on multiple dates. Predictive co-correspondence analyses indicated more support for the hypothesis that fungal community composition influenced plant community composition than vice versa. However, we found no evidence that altered rainfall regimes were leading to distinct co-associations between plants and AM fungi. Overall, our results provide evidence that grassland plant communities are intricately tied to variation in AM fungal communities. However, in this system, plant responses to climate change may not be directly related to impacts of altered rainfall regimes on AM fungal communities. Our study shows that AM fungal communities respond to changes in rainfall but that this effect was not immediate. The AM fungal community may influence the composition of the plant community. However, our results suggest that plant responses to altered rainfall regimes at our site may not be resulting via changes in the AM fungal communities.

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Influence of Long-term Fertilizations on Nutrients and Fungal Communities in Typical Paddy Soil of South China

ACTA AGRONOMICA SINICA ◽

10.3724/sp.j.1006.2017.00286 ◽

2017 ◽

Vol 43 (2) ◽

pp. 286 ◽

Cited By ~ 2

Author(s):

Dan-Mei CHEN ◽

Ling YUAN ◽

Jian-Guo HUANG ◽

Jian-Hua JI ◽

Hong-Qian HOU ◽

...

Keyword(s):

South China ◽

Paddy Soil ◽

Fungal Communities

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Impact of the divorce experience on the marital and family mindsets

Russian Foundation for Basic Research Journal Humanities and social sciences ◽

10.22204/2587-8956-2018-090-01-88-96 ◽

2018 ◽

pp. 88-96

Author(s):

Елена Лактюхина ◽

Elena Laktyukhina ◽

Георгий Антонов ◽

Georgy Antonov

Keyword(s):

Comparative Analysis ◽

Demographic Characteristics ◽

Representative Sampling ◽

First Marriage ◽

Active Population ◽

Volgograd Region ◽

The Social ◽

Marriage Stability ◽

Main Factors ◽

The Individual

The article presents a comparative analysis of marital and family mindsets of two categories of the demographically active population of modern Russia: (1) individuals that have no experience of a divorce and (2) those who have already experienced one or more official termination of a marriage. The empirical base of the analysis is the data of the author’s questionnaire survey conducted by representative sampling in Volgograd and Volgograd Region in 2015–2016. The analysis was made on the following basic empiric indicators: optimal (from the viewpoint of the respondents) age for the first marriage, frequency of mentioning marital and family statuses as the respondents describe their own social and demographic “portrait”, legitimate causes of a divorce and a number of others. It is found that, in the case of sufficiently strong traditional marital and family mindsets, perception of marital norms is adjusted, if an “abnormal” event (such as a divorce) occurs in the individual’s life course. At the same time, perception of the marriage stability is less variable and does not depend on the social and demographic characteristics of the respondents, including the presence/absence of a marriage termination experience. The “strongest” factor that affects the change of the marital and family mindsets is age. With age (and, consequently, experience accumulation), importance of the majority of main factors capable of preventing the individual from a divorce decreases and, therefore, the risk of such event increases.

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Fungal Diversity in the Phyllosphere of Pinus heldreichii H. Christ—An Endemic and High-Altitude Pine of the Mediterranean Region

Diversity ◽

10.3390/d12050172 ◽

2020 ◽

Vol 12 (5) ◽

pp. 172 ◽

Cited By ~ 3

Author(s):

Jelena Lazarević ◽

Audrius Menkis

Keyword(s):

High Altitude ◽

Bark Beetles ◽

Fungal Pathogens ◽

High Throughput Sequencing ◽

Fungal Communities ◽

High Quality ◽

The Balkans ◽

Fungal Community Structure ◽

Growing Conditions ◽

Coniferous Tree Species

Pinus heldreichii is a high-altitude coniferous tree species naturaly occurring in small and disjuncted populations in the Balkans and southern Italy. The aim of this study was to assess diversity and composition of fungal communities in living needles of P. heldreichii specifically focusing on fungal pathogens. Sampling was carried out at six different sites in Montenegro, where 2-4 year-old living needles of P. heldreichii were collected. Following DNA isolation, it was amplified using ITS2 rDNA as a marker and subjected to high-throughput sequencing. Sequencing resulted in 31,831 high quality reads, which after assembly were found to represent 375 fungal taxa. The detected fungi were 295 (78.7%) Ascomycota, 79 (21.0%) Basidiomycota and 1 (0.2%) Mortierellomycotina. The most common fungi were Lophodermium pinastri (12.5% of all high-quality sequences), L. conigenum (10.9%), Sydowia polyspora (8.8%), Cyclaneusma niveum (5.5%), Unidentified sp. 2814_1 (5.4%) and Phaeosphaeria punctiformis (4.4%). The community composition varied among different sites, but in this respect two sites at higher altitudes (harsh growing conditions) were separated from three sites at lower altitudes (milder growing conditions), suggesting that environmental conditions were among major determinants of fungal communities associated with needles of P. heldreichii. Trees on one study site were attacked by bark beetles, leading to discolouration and frequent dieback of needles, thereby strongly affecting the fungal community structure. Among all functional groups of fungi, pathogens appeared to be an important component of fungal communities in the phyllosphere of P. heldreichii, especially in those trees under strong abiotic and biotic stress.

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Rock Surface Fungi in Deep Continental Biosphere—Exploration of Microbial Community Formation with Subsurface In Situ Biofilm Trap

Microorganisms ◽

10.3390/microorganisms9010064 ◽

2020 ◽

Vol 9 (1) ◽

pp. 64

Author(s):

Maija Nuppunen-Puputti ◽

Riikka Kietäväinen ◽

Lotta Purkamo ◽

Pauliina Rajala ◽

Merja Itävaara ◽

...

Keyword(s):

Significant Proportion ◽

Debaryomyces Hansenii ◽

Fungal Communities ◽

Fungal Colonization ◽

Rock Surface ◽

Mica Schist ◽

Deep Subsurface ◽

Bacterial Phyla ◽

In Situ Conditions

Fungi have an important role in nutrient cycling in most ecosystems on Earth, yet their ecology and functionality in deep continental subsurface remain unknown. Here, we report the first observations of active fungal colonization of mica schist in the deep continental biosphere and the ability of deep subsurface fungi to attach to rock surfaces under in situ conditions in groundwater at 500 and 967 m depth in Precambrian bedrock. We present an in situ subsurface biofilm trap, designed to reveal sessile microbial communities on rock surface in deep continental groundwater, using Outokumpu Deep Drill Hole, in eastern Finland, as a test site. The observed fungal phyla in Outokumpu subsurface were Basidiomycota, Ascomycota, and Mortierellomycota. In addition, significant proportion of the community represented unclassified Fungi. Sessile fungal communities on mica schist surfaces differed from the planktic fungal communities. The main bacterial phyla were Firmicutes, Proteobacteria, and Actinobacteriota. Biofilm formation on rock surfaces is a slow process and our results indicate that fungal and bacterial communities dominate the early surface attachment process, when pristine mineral surfaces are exposed to deep subsurface ecosystems. Various fungi showed statistically significant cross-kingdom correlation with both thiosulfate and sulfate reducing bacteria, e.g., SRB2 with fungi Debaryomyces hansenii.

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