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1.
Environ Sci Technol ; 57(49): 20636-20646, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-38011382

RESUMO

Cyanobacterial harmful algal blooms (CyanoHABs) pose serious risks to inland water resources. Despite advancements in our understanding of associated environmental factors and modeling efforts, predicting CyanoHABs remains challenging. Leveraging an integrated water quality data collection effort in Iowa lakes, this study aimed to identify factors associated with hazardous microcystin levels and develop one-week-ahead predictive classification models. Using water samples from 38 Iowa lakes collected between 2018 and 2021, feature selection was conducted considering both linear and nonlinear properties. Subsequently, we developed three model types (Neural Network, XGBoost, and Logistic Regression) with different sampling strategies using the nine selected variables (mcyA_M, TKN, % hay/pasture, pH, mcyA_M:16S, % developed, DOC, dewpoint temperature, and ortho-P). Evaluation metrics demonstrated the strong performance of the Neural Network with oversampling (ROC-AUC 0.940, accuracy 0.861, sensitivity 0.857, specificity 0.857, LR+ 5.993, and 1/LR- 5.993), as well as the XGBoost with downsampling (ROC-AUC 0.944, accuracy 0.831, sensitivity 0.928, specificity 0.833, LR+ 5.557, and 1/LR- 11.569). This study exhibited the intricacies of modeling with limited data and class imbalances, underscoring the importance of continuous monitoring and data collection to improve predictive accuracy. Also, the methodologies employed can serve as meaningful references for researchers tackling similar challenges in diverse environments.


Assuntos
Cianobactérias , Proliferação Nociva de Algas , Lagos/microbiologia , Iowa
2.
mSystems ; 6(5): e0020121, 2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34546069

RESUMO

Genes belonging to the same functional group may include numerous and variable gene sequences, making characterizing and quantifying difficult. Therefore, high-throughput design tools are needed to simultaneously create primers for improved quantification of target genes. We developed MetaFunPrimer, a bioinformatic pipeline, to design primers for numerous genes of interest. This tool also enables gene target prioritization based on ranking the presence of genes in user-defined references, such as environment-specific metagenomes. Given inputs of protein and nucleotide sequences for gene targets of interest and an accompanying set of reference metagenomes or genomes, MetaFunPrimer generates primers for ranked genes of interest. To demonstrate the usage and benefits of MetaFunPrimer, a total of 78 primer pairs were designed to target observed ammonia monooxygenase subunit A (amoA) genes of ammonia-oxidizing bacteria (AOB) in 1,550 publicly available soil metagenomes. We demonstrate computationally that these amoA-AOB primers can cover 94% of the amoA-AOB genes observed in the 1,550 soil metagenomes compared with a 49% estimated coverage by previously published primers. Finally, we verified the utility of these primer sets in incubation experiments that used long-term nitrogen fertilized or unfertilized soils. High-throughput quantitative PCR (qPCR) results and statistical analyses showed significant differences in relative quantification patterns between the two soils, and subsequent absolute quantifications also confirmed that target genes enumerated by six selected primer pairs were significantly more abundant in the nitrogen-fertilized soils. This new tool gives microbial ecologists a new approach to assess functional gene abundance and related microbial community dynamics quickly and affordably. IMPORTANCE Amplification-based gene characterization allows for sensitive and specific quantification of functional genes. There is often a large diversity of genes represented for functional gene groups, and multiple primers may be necessary to target associated genes. Current primer design tools are limited to designing primers for only a few genes of interest. MetaFunPrimer allows for high-throughput primer design for various genes of interest and also allows for ranking gene targets by their presence and abundance in environmental data sets. Primers designed by this tool improve the characterization and quantification of functional genes in broad gene amplification platforms and can be powerful with high-throughput qPCR approaches.

3.
Trop Med Infect Dis ; 2(3)2017 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-30270886

RESUMO

Over five years, a total of 646 P. aeruginosa isolates was acquired from different clinical specimens and their resistance to the commonly used anti-pseudomonal antibiotics was determined. The majority of the isolates were from respiratory (60.99%) and urinary sources (23.22%) while the least came from transudates and exudates (2.01%). Most of the samples were acquired from older adults (77.55%), most of whom were admitted (67.03%). Amikacin was found to be the most effective drug with a resistance rate of 7.5%, followed by piperacillin/tazobactam (8.5%) and gentamicin (13.5%). On the other hand, 26.7% of the isolates were resistant to levofloxacin. Almost 100% of the isolates were screened positive for AmpC production, which may suggest inducible resistance against expanded spectrum beta-lactamase. Furthermore, for the last three years, P. aeruginosa isolates from this area have been noted to have decreasing resistance only to aztreonam and gentamicin. Also, for five years, a mean MAR index of 0.17 was noted which indicates either proper antibiotic use or most isolates did not come from high-risk areas. Moreover, there was no significant difference in the resistance of P. aeruginosa when compared by specimen source (p = 0.662), but significant when compared by year band (p = 0.02).

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