scholarly journals RefSeq database growth influences the accuracy of k-mer-based species identification

2018 ◽  
Author(s):  
Daniel J. Nasko ◽  
Sergey Koren ◽  
Adam M. Phillippy ◽  
Todd J. Treangen
Keyword(s):  
Microbial Communities ◽  
Strong Influence ◽  
Species Level ◽  
Sequence Classification ◽  
Closely Related Species ◽  
Large Genome ◽  
Classification Uncertainty ◽  
Target Strain ◽  
New Algorithms ◽  
Over Time

ABSTRACTAccurate species-level taxonomic classification and profiling of complex microbial communities remains a challenge due to homologous regions shared among closely related species and a sparse representation of non-human associated microbes in the database. Although the database undoubtedly has a strong influence on the sensitivity of taxonomic classifiers and profilers, to date, no study has carefully explored this topic on historical RefSeq releases and explored its impact on accuracy. In this study, we examined the influence of the database, over time, on k-mer based sequence classification and profiling. We present three major findings: (i) database growth over time resulted in more classified reads, but fewer species-level classifications and more species-level misclassifications; (ii) Bayesian re-estimation of abundance helped to recover species-level classifications when the exact target strain was present; and (iii) Bayesian reestimation struggled when the database lacked the target strain, resulting in a notable decrease in accuracy. In summary, our findings suggest that the growth of RefSeq over time has strongly influenced the accuracy of k-mer based classification and profiling methods, resulting in different classification results depending on the particular database used. These results suggest a need for new algorithms specially adapted for large genome collections and better measures of classification uncertainty.

scholarly journals Serial Analysis of the Gut and Respiratory Microbiome in Cystic Fibrosis in Infancy: Interaction between Intestinal and Respiratory Tracts and Impact of Nutritional Exposures

mBio ◽  
2012 ◽  
Vol 3 (4) ◽  
Author(s):  
J. C. Madan ◽  
D. C. Koestler ◽  
B. A. Stanton ◽  
L. Davidson ◽  
L. A. Moulton ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Respiratory Tract ◽  
Microbial Communities ◽  
Effective Means ◽  
Significant Proportion ◽  
Gut Colonization ◽  
Pulmonary Damage ◽  
Chronic Colonization ◽  
High Degree ◽  
Over Time

ABSTRACT Pulmonary damage caused by chronic colonization of the cystic fibrosis (CF) lung by microbial communities is the proximal cause of respiratory failure. While there has been an effort to document the microbiome of the CF lung in pediatric and adult patients, little is known regarding the developing microflora in infants. We examined the respiratory and intestinal microbiota development in infants with CF from birth to 21 months. Distinct genera dominated in the gut compared to those in the respiratory tract, yet some bacteria overlapped, demonstrating a core microbiota dominated by Veillonella and Streptococcus. Bacterial diversity increased significantly over time, with evidence of more rapidly acquired diversity in the respiratory tract. There was a high degree of concordance between the bacteria that were increasing or decreasing over time in both compartments; in particular, a significant proportion (14/16 genera) increasing in the gut were also increasing in the respiratory tract. For 7 genera, gut colonization presages their appearance in the respiratory tract. Clustering analysis of respiratory samples indicated profiles of bacteria associated with breast-feeding, and for gut samples, introduction of solid foods even after adjustment for the time at which the sample was collected. Furthermore, changes in diet also result in altered respiratory microflora, suggesting a link between nutrition and development of microbial communities in the respiratory tract. Our findings suggest that nutritional factors and gut colonization patterns are determinants of the microbial development of respiratory tract microbiota in infants with CF and present opportunities for early intervention in CF with altered dietary or probiotic strategies. IMPORTANCE While efforts have been focused on assessing the microbiome of pediatric and adult cystic fibrosis (CF) patients to understand how chronic colonization by these microbes contributes to pulmonary damage, little is known regarding the earliest development of respiratory and gut microflora in infants with CF. Our findings suggest that colonization of the respiratory tract by microbes is presaged by colonization of the gut and demonstrated a role of nutrition in development of the respiratory microflora. Thus, targeted dietary or probiotic strategies may be an effective means to change the course of the colonization of the CF lung and thereby improve patient outcomes.

scholarly journals Behaviour of cranes (family Gruidae) mirrors their phylogenetic relationships

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nela Nováková ◽  
Jan Robovský
Keyword(s):  
Phylogenetic Relationships ◽  
Phylogenetic Signal ◽  
Species Level ◽  
Monophyletic Group ◽  
Molecular Tree ◽  
Behavioural Repertoire ◽  
Over Time

Abstract Background The behavioural repertoire of every species evolved over time and its evolution can be traced through the phylogenetic relationships in distinct groups. Cranes (family Gruidae) represent a small, old, monophyletic group with well-corroborated phylogenetic relationships on the species level, and at the same time they exhibit a complex and well-described behavioural repertoire. Methods We therefore investigated the evolution of behavioural traits of cranes in a phylogenetic context using several phylogenetic approaches and two types of trait scoring. The cranes exhibit more than a hundred behavioural displays, almost one third of which may be phylogenetically informative. Results More than half of the analysed traits carry a significant phylogenetic signal. The ancestor of cranes already exhibited a quite complex behavioural repertoire, which remained unchanged in Balearicinae but altered greatly in Gruinae, specifically by the shedding of traits rather than their creation. Trait scoring has an influence on results within the Gruinae, primarily in genera Bugeranus and Anthropoides. Conclusions Albeit the behavioural traits alone cannot be used for resolving species-level relationships within the Gruidae, when optimized on molecular tree, they can help us to detect interesting evolutionary transformations of behaviour repertoire within Gruiformes. The Limpkin (Aramus guarauna) seems to be the most enigmatic species and should be studied in detail for its behavioural repertoire, which may include some precursors of crane behavioural traits.

scholarly journals Dissecting individual pathogen-commensal interactions within a complex gut microbiota community

2020 ◽  
Author(s):  
Jack Hassall ◽  
Meera Unnikrishnan
Keyword(s):  
Gut Microbiota ◽  
Single Species ◽  
Species Level ◽  
Commensal Bacteria ◽  
Individual Species ◽  
Community Responses ◽  
Bacterial Interactions ◽  
Gut Pathogen ◽  
Over Time

AbstractInteractions of commensal bacteria within the gut microbiota and with invading pathogens are critical in determining the outcome of an infection. While murine studies have been valuable, we lack in vitro tools to monitor community responses to pathogens at a single-species level. We have developed a multi-species community of nine representative gut species cultured together as a mixed biofilm and tracked numbers of individual species over time using a qPCR-based approach. Introduction of the major nosocomial gut pathogen, Clostridiodes difficile, to this community resulted in increased adhesion of commensals and inhibition of C. difficile multiplication. Interestingly, we observed an increase in individual Bacteroides species accompanying the inhibition of C. difficile. Furthermore, Bacteroides dorei reduced C. difficile growth within biofilms, suggesting a role for Bacteroides spp in prevention of C. difficile colonisation. We report here an in vitro tool with excellent applications for investigating bacterial interactions within a complex community.

scholarly journals Soil microbial communities in the face of changing farming practices: A case study in an agricultural landscape in France

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252216
Author(s):  
Laurie Dunn ◽  
Christophe Lang ◽  
Nicolas Marilleau ◽  
Sébastien Terrat ◽  
Luc Biju-Duval ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Properties ◽  
Microbial Communities ◽  
Soil Microorganisms ◽  
Soil Microbial Communities ◽  
Partial Least Square ◽  
Farming Practices ◽  
Soil Microbial ◽  
Bacterial Richness ◽  
Over Time

According to biogeography studies, the abundance and richness of soil microorganisms vary across multiple spatial scales according to soil properties and farming practices. However, soil microorganisms also exhibit poorly understood temporal variations. This study aimed at better understanding how soil microbial communities respond to changes in farming practices at a landscape scale over time. A regular grid of 269 sites was set up across a 1,200 ha farming landscape, and soil samples were characterized for their molecular microbial biomass and bacterial richness at two dates (2011 and 2016). A mapping approach highlighted that spatial microbial patterns were stable over time, while abundance and richness levels were modified. The drivers of these changes were investigated though a PLS-PM (partial least square path-modeling) approach. Soil properties were stable over time, but farming practices changed. Molecular microbial biomass was mainly driven by soil resources, whereas bacterial richness depended on both farming practices and ecological parameters. Previous-crop and management effects and a temporal dependence of the microbial community on the historical farming management were also highlighted.

Big Data Analytics

2018 ◽  
pp. 124-138
Author(s):  
Sreenu G. ◽  
M.A. Saleem Durai
Keyword(s):  
Decision Making ◽  
Big Data ◽  
Real Life ◽  
Big Data Analytics ◽  
Speed Up ◽  
Processing Techniques ◽  
And Storage ◽  
Big Data Computing ◽  
New Algorithms ◽  
Over Time

Advances in recent hardware technology have permitted to document transactions and other pieces of information of everyday life at an express pace. In addition of speed up and storage capacity, real-life perceptions tend to transform over time. However, there are so much prospective and highly functional values unseen in the vast volume of data. For this kind of applications conventional data mining is not suitable, so they should be tuned and changed or designed with new algorithms. Big data computing is inflowing to the category of most hopeful technologies that shows the way to new ways of thinking and decision making. This epoch of big data helps users to take benefit out of all available data to gain more precise systematic results or determine latent information, and then make best possible decisions. Depiction from a broad set of workloads, the author establishes a set of classifying measures based on the storage architecture, processing types, processing techniques and the tools and technologies used.

Phylogeny, systematics and rarity assessment of New Zealand endemic Saphydrus beetles and related enigmatic larvae (Coleoptera : Hydrophilidae : Cylominae)

2020 ◽  
Author(s):  
Matthias Seidel ◽  
Yûsuke N. Minoshima ◽  
Richard A. B. Leschen ◽  
Martin Fikácek
Keyword(s):  
New Zealand ◽  
Adult Stage ◽  
Single Species ◽  
Species Level ◽  
Phylogenetic Position ◽  
Primary Reason ◽  
Altitudinal Distribution ◽  
Population Number ◽  
Threatened Status ◽  
Over Time

The New Zealand endemic beetle genus Saphydrus Sharp, 1884 (Coleoptera:Hydrophilidae:Cylominae) is studied in order to understand its phylogenetic position, species-level systematics, biology and distribution, and to reveal reasons for its rarity. The first complete genus-level phylogeny of Cylominae based on two mitochondrial (cox1, 16S) and two nuclear genes (18S, 28S) covering 18 of 19 genera of the subfamily reveals Saphydrus as an isolated lineage situated in a clade with Cylorygmus (South America), Relictorygmus (South Africa) and Eurygmus (Australia). DNA is used to associate two larval morphotypes with Saphydrus: one of them represents the larvae of S. suffusus Sharp, 1884; the other, characterised by unique characters of the head and prothorax morphology, is revealed as sister but not closely related to Saphydrus. It is described here as Enigmahydrus, gen. nov. with a single species, E. larvalis, sp. nov., whose adult stage remains unknown. Saphydrus includes five species, two of which (S. moeldnerae, sp. nov. and S. tanemahuta, sp. nov.) are described as new. Larvae of Enigmahydrus larvalis and Saphydrus suffusus are described and illustrated in detail based on DNA-identified specimens. Candidate larvae for Saphydrus obesus Sharp, 1884 and S. tanemahuta are illustrated and diagnosed. Specimen data are used to evaluate the range, altitudinal distribution, seasonality and population dynamics over time for all species. Strongly seasonal occurrence of adults combined with other factors (winter occurrence in S. obesus, occurrence at high altitudes in S. tanemahuta) is hypothesised as the primary reason of the rarity for Saphydrus species. By contrast, Enigmahydrus larvalis underwent a strong decline in population number and size since the 1970s and is currently known from a single, locally limited population; we propose the ‘nationally threatened’ status for this species. http://zoobank.org/urn:lsid:zoobank.org:pub:28D87163-29E8-418C-9380-262D3038023A

scholarly journals Global airborne microbial communities controlled by surrounding landscapes and wind conditions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Romie Tignat-Perrier ◽  
Aurélien Dommergue ◽  
Alban Thollot ◽  
Christoph Keuschnig ◽  
Olivier Magand ◽  
...  
Keyword(s):  
Particulate Matter ◽  
High Altitude ◽  
Microbial Communities ◽  
Atmospheric Chemistry ◽  
Sampling Site ◽  
Temporal Stability ◽  
Fungal Species ◽  
The World ◽  
Bacteria And Fungi ◽  
Over Time

Abstract The atmosphere is an important route for transporting and disseminating microorganisms over short and long distances. Understanding how microorganisms are distributed in the atmosphere is critical due to their role in public health, meteorology and atmospheric chemistry. In order to determine the dominant processes that structure airborne microbial communities, we investigated the diversity and abundance of both bacteria and fungi from the PM10 particle size (particulate matter of 10 micrometers or less in diameter) as well as particulate matter chemistry and local meteorological characteristics over time at nine different meteorological stations around the world. The bacterial genera Bacillus and Sphingomonas as well as the fungal species Pseudotaeniolina globaosa and Cladophialophora proteae were the most abundant taxa of the dataset, although their relative abundances varied greatly based on sampling site. Bacterial and fungal concentration was the highest at the high-altitude and semi-arid plateau of Namco (China; 3.56 × 106 ± 3.01 × 106 cells/m3) and at the high-altitude and vegetated mountain peak Storm-Peak (Colorado, USA; 8.78 × 104 ± 6.49 × 104 cells/m3), respectively. Surrounding ecosystems, especially within a 50 km perimeter of our sampling stations, were the main contributors to the composition of airborne microbial communities. Temporal stability in the composition of airborne microbial communities was mainly explained by the diversity and evenness of the surrounding landscapes and the wind direction variability over time. Airborne microbial communities appear to be the result of large inputs from nearby sources with possible low and diluted inputs from distant sources.

scholarly journals Temporal Responses of Microbial Communities to Anaerobic Soil Disinfestation

2019 ◽  
Vol 80 (1) ◽  
pp. 191-201 ◽  
Author(s):  
Amisha T. Poret-Peterson ◽  
Nada Sayed ◽  
Nathaniel Glyzewski ◽  
Holly Forbes ◽  
Enid T. González-Orta ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Rice Bran ◽  
Grape Pomace ◽  
Soil Microbiome ◽  
Tomato Pomace ◽  
Soil Redox ◽  
Soil Disinfestation ◽  
Anaerobic Soil Disinfestation ◽  
Red Grape ◽  
Over Time

AbstractAnaerobic soil disinfestation (ASD) is an organic amendment-based management tool for controlling soil-borne plant diseases and is increasingly used in a variety of crops. ASD results in a marked decrease in soil redox potential and other physicochemical changes, and a turnover in the composition of the soil microbiome. Mechanisms of ASD-mediated pathogen control are not fully understood, but appear to depend on the carbon source used to initiate the process and involve a combination of biological (i.e., release of volatile organic compounds) and abiotic (i.e., lowered pH, release of metal ions) factors. In this study, we examined how the soil microbiome changes over time in response to ASD initiated with rice bran, tomato pomace, or red grape pomace as amendments using growth chamber mesocosms that replicate ASD-induced field soil redox conditions. Within 2 days, the soil microbiome rapidly shifted from a diverse assemblage of taxa to being dominated by members of the Firmicutes for all ASD treatments, whereas control mesocosms maintained diverse and more evenly distributed communities. Rice bran and tomato pomace amendments resulted in microbial communities with similar compositions and trajectories that were different from red grape pomace communities. Quantitative PCR showed nitrogenase gene abundances were higher in ASD communities and tended to increase over time, suggesting the potential for altering soil nitrogen availability. These results highlight the need for temporal and functional studies to understand how pathogen suppressive microbial communities assemble and function in ASD-treated soils.

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