نتایج جستجو برای: taxonomic units
تعداد نتایج: 197687 فیلتر نتایج به سال:
Both the weighted and unweighted Unifrac distances have been very successfully employed to assess if two communities differ, but do not give any information about how two communities differ. We take advantage of recent observations that the Unifrac metric is equivalent to the so-called earth mover’s distance (also known as the Kantorovich-Rubinstein metric) to develop an algorithm that not only...
From birth to the time after weaning the gastrointestinal microbiota of calves must develop into a stable, autochthonous community accompanied by pivotal changes of anatomy and physiology of the gastrointestinal tract. The aim of this pilot study was to examine the fecal microbiota of six Simmental dairy calves to investigate time-dependent dynamics of the microbial community. Calves were follo...
High-throughput sequencing of small-subunit (SSU) rRNA genes has revolutionized understanding of microbial communities and facilitated investigations into ecological dynamics at unprecedented scales. Such extensive SSU rRNA gene sequence libraries, constructed from DNA extracts of environmental or host-associated samples, often contain a substantial proportion of unclassified sequences, many re...
Recent gut microbiome studies in model organisms emphasize the effects of intrinsic and extrinsic factors on the variation of the bacterial composition and its impact on the overall health status of the host. Species occurring in the same habitat might share a similar microbiome, especially if they overlap in ecological and behavioral traits. So far, the natural variation in microbiomes of free...
In the biogeography of microorganisms, the habitat size of an attached-living bacterium has never been investigated. We approached this theme with a multilocus sequence analysis (MLSA) study of new strains of Rhodopirellula sp., an attached-living planctomycete. The development of an MLSA for Rhodopirellula baltica enabled the characterization of the genetic diversity at the species level, beyo...
Bacterial communities in the different regions of gastrointestinal tract (GIT) of broiler chickens were analyzed by pyrosequencing approach to understand microbial composition and diversity. The DNA samples extracted from 7 different regions along the GIT were subjected to bacterial-community analysis by pyrosequencing of the V1-V3 region of 16S rRNA gene. Major bacterial phyla in the chicken-g...
The primary purpose ofDNA-barcoding projects is to generate an efficient expertise and identification tool. This is an important challenge to the taxonomy of the 21st century, as the demand increases and the expert capacity does not. However, identifying specimens usingDNA-barcodes requires a preliminary analysis to relatemolecular clusters to available scientific names. Through a case study of...
Objective Our previous studies found that disturbances in gut microbiota might have a causative role in the onset of major depressive disorder (MDD). The aim of this study was to investigate whether there were sex differences in gut microbiota in patients with MDD. Patients and methods First-episode drug-naïve MDD patients and healthy controls were included. 16S rRNA gene sequences extracted ...
Peanut yield and quality are seriously affected by pod rot pathogens worldwide, especially in China in recent years. The goals of this study are to analyze the structure of fungal communities of peanut pod rot in soil in three peanut cultivars and the correlation of pod rot with environmental variables using 454 pyrosequencing. A total of 46,723 internal transcribed spacer high-quality sequence...
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