Enhancing stability of aerobic granules by microbial selection pressure using height-adjustable influent strategy

2021 ◽  
pp. 117356
Author(s):  
Jia-heng Zhou ◽  
Qing Ren ◽  
Xiao-lei Xu ◽  
Jing-yuan Fang ◽  
Tao Wang ◽  
...  
Keyword(s):  
Selection Pressure ◽  
Aerobic Granules

Improved stability and performance of aerobic granules under stepwise increased selection pressure

2007 ◽  
Vol 41 (3) ◽  
pp. 205-211 ◽  
Author(s):  
X.H. Wang ◽  
H.M. Zhang ◽  
F.L. Yang ◽  
L.P. Xia ◽  
M.M. Gao
Keyword(s):  
Selection Pressure ◽  
Aerobic Granules ◽  
Improved Stability ◽  
And Performance

scholarly journals Amino-Acid Co-Variation in HIV-1 Gag Subtype C: HLA-Mediated Selection Pressure and Compensatory Dynamics

PLoS ONE ◽  
2010 ◽  
Vol 5 (9) ◽  
pp. e12463 ◽  
Author(s):  
Morgane Rolland ◽  
Jonathan M. Carlson ◽  
Siriphan Manocheewa ◽  
J. Victor Swain ◽  
Erinn Lanxon-Cookson ◽  
...  
Keyword(s):  
Amino Acid ◽  
Selection Pressure ◽  
Subtype C ◽  
Hiv 1

scholarly journals Whole-Genome Sequence Analysis of Pseudorabies Virus Clinical Isolates from Pigs in China between 2012 and 2017 in China

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1322
Author(s):  
Ruiming Hu ◽  
Leyi Wang ◽  
Qingyun Liu ◽  
Lin Hua ◽  
Xi Huang ◽  
...  
Keyword(s):  
Selection Pressure ◽  
Pseudorabies Virus ◽  
Viral Evolution ◽  
Infectious Agent ◽  
Genomic Diversity ◽  
Whole Genome Sequence ◽  
Evolutionary Constraint ◽  
The Novel ◽  
Novel Variants ◽  
Pressure Analysis

Pseudorabies virus (PRV) is an economically significant swine infectious agent. A PRV outbreak took place in China in 2011 with novel virulent variants. Although the association of viral genomic variability with pathogenicity is not fully confirmed, the knowledge concerning PRV genomic diversity and evolution is still limited. Here, we sequenced 54 genomes of novel PRV variants isolated in China from 2012 to 2017. Phylogenetic analysis revealed that China strains and US/Europe strains were classified into two separate genotypes. PRV strains isolated from 2012 to 2017 in China are highly related to each other and genetically close to classic China strains such as Ea, Fa, and SC. RDP analysis revealed 23 recombination events within novel PRV variants, indicating that recombination contributes significantly to the viral evolution. The selection pressure analysis indicated that most ORFs were under evolutionary constraint, and 19 amino acid residue sites in 15 ORFs were identified under positive selection. Additionally, 37 unique mutations were identified in 19 ORFs, which distinguish the novel variants from classic strains. Overall, our study suggested that novel PRV variants might evolve from classical PRV strains through point mutation and recombination mechanisms.

scholarly journals Metagenomic analyses and genetic diversity of Tomato leaf curl Arusha virus affecting tomato plants in Kenya

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Edith Khamonya Avedi ◽  
Adedapo Olutola Adediji ◽  
Dora Chao Kilalo ◽  
Florence Mmogi Olubayo ◽  
Isaac Macharia ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Selection Pressure ◽  
Management Strategies ◽  
Purifying Selection ◽  
Tomato Leaf ◽  
Amino Acid Sequences ◽  
Virus Population ◽  
Tomato Production ◽  
Tomato Leaf Curl ◽  
Leaf Curl

Abstract Background Tomato production is threatened worldwide by the occurrence of begomoviruses which are associated with tomato leaf curl diseases. There is little information on the molecular properties of tomato begomoviruses in Kenya, hence we investigated the population and genetic diversity of begomoviruses associated with tomato leaf curl in Kenya. Methods Tomato leaf samples with virus-like symptoms were obtained from farmers’ field across the country in 2018 and Illumina sequencing undertaken to determine the genetic diversity of associated begomoviruses. Additionally, the occurrence of selection pressure and recombinant isolates within the population were also evaluated. Results Twelve complete begomovirus genomes were obtained from our samples with an average coverage of 99.9%. The sequences showed 95.7–99.7% identity among each other and 95.9–98.9% similarities with a Tomato leaf curl virus Arusha virus (ToLCArV) isolate from Tanzania. Analysis of amino acid sequences showed the highest identities in the regions coding for the coat protein gene (98.5–100%) within the isolates, and 97.1–100% identity with the C4 gene of ToLCArV. Phylogenetic algorithms clustered all Kenyan isolates in the same clades with ToLCArV, thus confirming the isolates to be a variant of the virus. There was no evidence of recombination within our isolates. Estimation of selection pressure within the virus population revealed the occurrence of negative or purifying selection in five out of the six coding regions of the sequences. Conclusions The begomovirus associated with tomato leaf curl diseases of tomato in Kenya is a variant of ToLCArV, possibly originating from Tanzania. There is low genetic diversity within the virus population and this information is useful in the development of appropriate management strategies for the disease in the country.

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