scholarly journals The presence of Pseudogymnoascus destructans, a fungal pathogen of bats, correlates with changes in microbial metacommunity structure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthew Grisnik ◽  
Joshua B. Grinath ◽  
Donald M. Walker
Keyword(s):  
Community Structure ◽  
Community Composition ◽  
Common Core ◽  
Fungal Pathogen ◽  
Pseudogymnoascus Destructans ◽  
Community Patterns ◽  
Host Health ◽  
Microbial Group ◽  
Metacommunity Structure ◽  
The Relationship

AbstractMetacommunity theory provides a framework for how community patterns arise from processes across scales, which is relevant for understanding patterns in host-associated microbial assemblages. Microbial metacommunities may have important roles in host health through interactions with pathogens; however, it is unclear how pathogens affect host microbial metacommunities. Here, we studied relationships between a fungal pathogen and a host-associated microbial metacommunity. We hypothesized that a fungal pathogen of bats, Pseudogymnoascus destructans, correlates with a shift in metacommunity structure and changes in relationships between community composition, and factors shaping these assemblages, such as ecoregion. We sampled bat cutaneous microbial assemblages in the presence/absence of P. destructans and analyzed microbial metacommunity composition and relationships with structuring variables. Absence of P. destructans correlated with a metacommunity characterized by a common core microbial group that was lacking in disease positive bats. Additionally, P. destructans presence correlated with a change in the relationship between community structure and ecoregion. Our results suggest that the fungal pathogen intensifies local processes influencing a microbial metacommunity and highlights the importance of cutaneous microbial assemblages in host–pathogen interactions.

Dissolved oxygen and temperature best predict deep-sea fish community structure in the Gulf of California with climate change implications

2020 ◽  
Vol 637 ◽  
pp. 159-180
Author(s):  
ND Gallo ◽  
M Beckwith ◽  
CL Wei ◽  
LA Levin ◽  
L Kuhnz ◽  
...  
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Community Composition ◽  
Environmental Conditions ◽  
Deep Sea ◽  
Gulf Of California ◽  
Fish Community ◽  
Demersal Fish ◽  
Fish Community Structure ◽  
Explained Variance

Natural gradient systems can be used to examine the vulnerability of deep-sea communities to climate change. The Gulf of California presents an ideal system for examining relationships between faunal patterns and environmental conditions of deep-sea communities because deep-sea conditions change from warm and oxygen-rich in the north to cold and severely hypoxic in the south. The Monterey Bay Aquarium Research Institute (MBARI) remotely operated vehicle (ROV) ‘Doc Ricketts’ was used to conduct seafloor video transects at depths of ~200-1400 m in the northern, central, and southern Gulf. The community composition, density, and diversity of demersal fish assemblages were compared to environmental conditions. We tested the hypothesis that climate-relevant variables (temperature, oxygen, and primary production) have more explanatory power than static variables (latitude, depth, and benthic substrate) in explaining variation in fish community structure. Temperature best explained variance in density, while oxygen best explained variance in diversity and community composition. Both density and diversity declined with decreasing oxygen, but diversity declined at a higher oxygen threshold (~7 µmol kg-1). Remarkably, high-density fish communities were observed living under suboxic conditions (<5 µmol kg-1). Using an Earth systems global climate model forced under an RCP8.5 scenario, we found that by 2081-2100, the entire Gulf of California seafloor is expected to experience a mean temperature increase of 1.08 ± 1.07°C and modest deoxygenation. The projected changes in temperature and oxygen are expected to be accompanied by reduced diversity and related changes in deep-sea demersal fish communities.

A Comparative Overview of the Fair Wear and Tear Exception: the Duty of Holders of Temporary Interests to Preserve Property

2002 ◽  
Vol 6 (1) ◽  
pp. 85-100
Author(s):  
Raffaele Caterina
Keyword(s):  
Common Core ◽  
Complete Solution ◽  
Roman Law ◽  
Private Ownership ◽  
Legal Systems ◽  
Personal Rights ◽  
Wear And Tear ◽  
Long Life ◽  
The Law ◽  
The Relationship

“A system of private ownership must provide for something more sophisticated than absolute ownership of the property by one person. A property owner needs to be able to do more than own it during his lifetime and pass it on to someone else on his death.”1 Those who own things with a long life quite naturally feel the urge to deal in segments of time. Most of the owner's ambitions in respect of time can be met by the law of contract. But contract does not offer a complete solution, since contracts create only personal rights. Certain of the owner's legitimate wishes can be achieved only if the law allows them to be given effect in rem—that is, as proprietary rights. Legal systems have responded differently to the need for proprietary rights limited in time. Roman law created usufruct and other iura in re aliena; English law created different legal estates. Every system has faced similar problems. One issue has been the extent to which the holder of a limited interest should be restricted in his or her use and enjoyment in order to protect the holders of other interests in the same thing. A common core of principles regulates the relationship between those who hold temporary interests and the reversioners. For instance, every system forbids holder of the possessory interest to damage the thing arbitrarily. But other rules are more controversial. This study focuses upon the rules which do not forbid, but compel, certain courses of action.

An island biogeography model for beta diversity and endemism: The roles of speciation, extinction and dispersal

2015 ◽  
Vol 08 (01) ◽  
pp. 1550011 ◽  
Author(s):  
Youhua Chen
Keyword(s):  
Numerical Simulation ◽  
Community Composition ◽  
Beta Diversity ◽  
Island Biogeography ◽  
Positive Relationship ◽  
Community Patterns ◽  
Speciation Rate ◽  
Immigration Rate ◽  
Extinction Rates

A community composition island biogeography model was developed to explain and predict two community patterns (beta diversity and endemism) with the consideration of speciation, extinction and dispersal processes. Results showed that rate of speciation is positively and linearly associated with beta diversity and endemism, that is, increasing species rates typically could increase the percentage of both endemism and beta diversity. The influences of immigration and extinction rates on beta diversity and endemism are nonlinear, but with numerical simulation, I could observe that increasing extinction rates would lead to decreasing percentage of endemism and beta diversity. The role of immigration rate is very similar to that of speciation rate, having a positive relationship with beta diversity and endemism. Finally, I found that beta diversity is closely related to the percentage of endemism. The slope of this positive relationship is determined jointly by different combinations of speciation, extinction and immigration rates.

Temporal patterns in the macrobenthic communities of the Hawkesbury estuary, New South Wales

1987 ◽  
Vol 38 (5) ◽  
pp. 607
Author(s):  
AR Jones
Keyword(s):  
Community Composition ◽  
Temporal Patterns ◽  
Single Species ◽  
Species Number ◽  
Community Patterns ◽  
Low Salinity ◽  
Number Of Species ◽  
South Wales ◽  
Physicochemical Factors ◽  
Number Of Individuals

Temporal patterns in number of species, number of individual animals and community composition of the soft-sediment zoobenthos of the Hawkesbury estuary are described and related to physicochemical factors. Replicate grabs were taken at 3-month intervals over 3 years (1977-1979) from sites located in three zones: the lower, middle and upper reaches. The number of species and number of individuals showed significant seasonal and annual differences in all zones. However, the pattern of these differences varied among sites and seasonal differences were not repeatable over years. Similarly, differences in community composition as revealed by classification were not seasonal. In the middle and lower reaches, these differences were apparently caused by the over- riding influence of non-seasonal climatic events, i.e. a major flood in 1978 and a drought throughout 1979. In the first two sampling following the flood, sample values for the numbers of both species and individuals were usually lowest and community composition was distinct from pre-flood and drought times. During the drought, the number of species was usually high and community composition relatively distinct. Whereas the number of species and community composition groupings were both significantly related to river discharge, the number of individuals was significantly correlated with temperature. All community variables were sometimes significantly related to salinity. The identity of numerically dominant species, as determined by Fager rankings, varied among times in both the lower and middle reaches. However, the polychaete Nephtys australiensis and the bivalve mollusc Notospisula trigonella were highest ranked overall in both zones. Community patterns in the low-salinity upper reaches differed from those further downstream by showing little change in numbers of species and community composition following the flood. Only the number of species was significantly correlated with any of the measured physicochemical variables, this being partly due to an influx of species during the drought. Furthermore, the upstream community was always dominated by the polychaete Ceratonereis limnetica and was thus the only community that could be characterised by a single species.

scholarly journals Rare microbes from diverse Earth biomes dominate community activity

2019 ◽  
Author(s):  
Rohan Sachdeva ◽  
Barbara J. Campbell ◽  
John F. Heidelberg
Keyword(s):  
Community Structure ◽  
Microbial Activity ◽  
Ecosystem Function ◽  
Total Activity ◽  
Reaction Rates ◽  
Community Activity ◽  
Crucial Component ◽  
Tightly Coupled ◽  
The Relationship

AbstractMicrobes are the Earth’s most numerous organisms and are instrumental in driving major global biological and chemical processes. Microbial activity is a crucial component of all ecosystems, as microbes have the potential to control any major biochemical process. In recent years, considerable strides have been made in describing the community structure,i.e. diversity and abundance, of microbes from the Earth’s major biomes. In virtually all environments studied, a few highly abundant taxa dominate the structure of microbial communities. Still, microbial diversity is high and is concentrated in the less abundant, or rare, fractions of the community,i.e. the “long tail” of the abundance distribution. The relationship between microbial community structure and activity, specifically the role of rare microbes, and its connection to ecosystem function, is not fully understood. We analyzed 12.3 million metagenomic and metatranscriptomic sequence assemblies and their genes from environmental, human, and engineered microbiomes, and show that microbial activity is dominated by rare microbes (96% of total activity) across all measured biomes. Further, rare microbial activity was comprised of traits that are fundamental to ecosystem and organismal health,e.g. biogeochemical cycling and infectious disease. The activity of rare microbes was also tightly coupled to temperature, revealing a link between basic biological processes,e.g. reaction rates, and community activity. Our study provides a broadly applicable and predictable paradigm that implicates rare microbes as the main microbial drivers of ecosystem function and organismal health.

scholarly journals Significant Differences in the Gut Bacterial Communities of Hooded Crane (Grus monacha) in Different Seasons at a Stopover Site on the Flyway

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 701 ◽  
Author(s):  
Fengling Zhang ◽  
Xingjia Xiang ◽  
Yuanqiu Dong ◽  
Shaofei Yan ◽  
Yunwei Song ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Community Composition ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Bacterial Community Composition ◽  
Stopover Site ◽  
Intestinal Bacterial Community ◽  
Hooded Crane ◽  
Grus Monacha

Intestinal bacterial communities form an integral component of the organism. Many factors influence gut bacterial community composition and diversity, including diet, environment and seasonality. During seasonal migration, birds use many habitats and food resources, which may influence their intestinal bacterial community structure. Hooded crane (Grus monacha) is a migrant waterbird that traverses long distances and occupies varied habitats. In this study, we investigated the diversity and differences in intestinal bacterial communities of hooded cranes over the migratory seasons. Fecal samples from hooded cranes were collected at a stopover site in two seasons (spring and fall) in Lindian, China, and at a wintering ground in Shengjin Lake, China. We analyzed bacterial communities from the fecal samples using high throughput sequencing (Illumina Mi-seq). Firmicutes, Proteobacteria, Tenericutes, Cyanobacteria, and Actinobacteria were the dominant phyla across all samples. The intestinal bacterial alpha-diversity of hooded cranes in winter was significantly higher than in fall and spring. The bacterial community composition significantly differed across the three seasons (ANOSIM, P = 0.001), suggesting that seasonal fluctuations may regulate the gut bacterial community composition of migratory birds. This study provides baseline information on the seasonal dynamics of intestinal bacterial community structure in migratory hooded cranes.

scholarly journals Community structure and centrality effects in the South African company network

2013 ◽  
Vol 44 (2) ◽  
pp. 35-43 ◽  
Author(s):  
I. Durbach ◽  
D Katshunga ◽  
H. Parker
Keyword(s):  
Community Structure ◽  
Social Network ◽  
South African ◽  
Stock Exchange ◽  
The South ◽  
Market Capitalization ◽  
Johannesburg Stock Exchange ◽  
The Relationship

This paper conducts a search for community structure in the South African company network, a social network whose elements are South African companies listed on the Johannesburg Stock Exchange. Companies are connected in this network if they share one or more directors on their respective boards. Discovered clusters, called communities, can be considered to be compartments of the network working relatively independently of one another, making their distribution and composition of some interest. We test whether the discovered communities of companies are (a) statistically significant, and (b) related to other attributes such as sector membership or market capitalization. We also investigate the relationship between the centrality of a company’s position in the network and its market capitalization.

scholarly journals Coupled changes in soil organic carbon fractions and microbial community composition in urban and suburban forests

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xueying Zhang ◽  
Xiaomei Chen ◽  
Muying Liu ◽  
Zhanying Xu ◽  
Hui Wei
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Community Composition ◽  
Microbial Community Structure ◽  
Soil Microorganisms ◽  
Microbial Community Composition ◽  
Soil C ◽  
Suburban Forests

Abstract Climate change and rapid urbanization have greatly impacted urban forest ecosystems and the carbon (C) cycle. To assess the effects of urbanization on forest soil C and soil microorganisms, six natural forests in a highly-urbanized region were selected as the research objects. Soil samples were collected to investigate the content and fractions of the soil organic carbon (SOC), as well as the soil microbial community composition. The results showed that the SOC content and fractions were substantially lower in the urban forests than in the suburban forests. Meanwhile, the total amount of phospholipid fatty acids (PLFAs) at suburban sites was twice more than that at urban sites, with shifts in microbial community structure. The potential differences in C inputs and nutrient limitation in urban forests may aggravate the low quantity and quality of SOC and consequently impact microbial community abundance and structure. Variation in microbial community structure was found to explain the loss of soil C pools by affecting the C inputs and promoting the decomposition of SOC. Therefore, the coupled changes in SOC and soil microorganisms induced by urbanization may adversely affect soil C sequestration in subtropical forests.

The political rationalities of indebtedness: Control, discipline, sovereignty

2019 ◽  
Vol 58 (3) ◽  
pp. 454-468
Author(s):  
Jean François Bissonnette
Keyword(s):  
Michel Foucault ◽  
Common Core ◽  
Gilles Deleuze ◽  
The Political ◽  
Power Dynamics ◽  
Important Phenomenon ◽  
The Common ◽  
The Relationship ◽  
Political Character ◽  
Loan Contract

This article examines the political character of debt relations, focusing in particular on the increasingly important phenomenon of personal indebtedness. Following Michel Foucault and Gilles Deleuze, it distinguishes between three forms of ‘rationality’ that explain the various power dynamics at play beneath the formal and seemingly voluntary loan contract. Debt first exemplifies the open-ended flows of power that circulate in the networked structures of the ‘societies of control’ described by Deleuze. Far from signaling the demise of the modern disciplines analyzed by Foucault, credit relations are, on the contrary, shown to depend on some of the normalizing procedures that constituted the common core of disciplinary institutions. Arguing for a synchronic approach to historical political rationalities, this article highlights the relationship between debt and sovereignty, showing the intrication of contemporary, financialized forms of capitalist exploitation and the state’s ancient pretension to exact from its citizens an infinite debt of existence. Debt thus combines the respective effects of control, discipline and sovereignty and constitutes as such a powerful technology for the governing of individuals and populations.

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