scholarly journals Responses of Bacterial Taxonomical Diversity Indicators to Pollutant Loadings in Experimental Wetland Microcosms

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 251
Author(s):  
Subhomita Ghosh Ghosh Roy ◽  
Charles F. Wimpee ◽  
S. Andrew McGuire ◽  
Timothy J. Ehlinger

Urbanization results in higher stormwater loadings of pollutants such as metals and nutrients into surface waters. This directly impacts organisms in aquatic ecosystems, including microbes. Sediment microbes are known for pollution reduction in the face of contamination, making bacterial communities an important area for bioindicator research. This study explores the pattern of bacterial responses to metal and nutrient pollution loading and seeks to evaluate whether bacterial indicators can be effective as a biomonitoring risk assessment tool for wetland ecosystems. Microcosms were built containing sediments collected from wetlands in the urbanizing Pike River watershed in southeastern Wisconsin, USA, with metals and nutrients added at 7 day intervals. Bacterial DNA was extracted from the microcosm sediments, and taxonomical profiles of bacterial communities were identified up to the genera level by sequencing 16S bacterial rRNA gene (V3–V4 region). Reduction of metals (example: 90% for Pb) and nutrients (example: 98% for NO3−) added in water were observed. The study found correlations between diversity indices of genera with metal and nutrient pollution as well as identified specific genera (including Fusibacter, Aeromonas, Arthrobacter, Bacillus, Bdellovibrio, and Chlorobium) as predictive bioindicators for ecological risk assessment for metal pollution.

2004 ◽  
Vol 70 (1) ◽  
pp. 468-474 ◽  
Author(s):  
Oliver Dilly ◽  
Jaap Bloem ◽  
An Vos ◽  
Jean Charles Munch

ABSTRACT Denaturing gradient gel electrophoresis (DGGE) of amplified fragments of genes coding for 16S rRNA was used to study the development of bacterial communities during decomposition of crop residues in agricultural soils. Ten strains were tested, and eight of these strains produced a single band. Furthermore, a mixture of strains yielded distinguishable bands. Thus, DGGE DNA band patterns were used to estimate bacterial diversity. A field experiment performed with litter in nylon bags was used to evaluate the bacterial diversity during the decomposition of readily degradable rye and more refractory wheat material in comparable luvisols and cambisols in northern, central, and southern Germany. The amount of bacterial DNA in the fresh litter was small. The DNA content increased rapidly after the litter was added to the soil, particularly in the rapidly decomposing rye material. Concurrently, diversity indices, such as the Shannon-Weaver index, evenness, and equitability, which were calculated from the number and relative abundance (intensity) of the bacterial DNA bands amplified from genes coding for 16S rRNA, increased during the course of decomposition. This general trend was not significant for evenness and equitability at any time. The indices were higher for the more degradation-resistant wheat straw than for the more easily decomposed rye grass. Thus, the DNA band patterns indicated that there was increasing bacterial diversity as decomposition proceeded and substrate quality decreased. The bacterial diversity differed for the sites in northern, central, and southern Germany, where the same litter material was buried in the soil. This shows that in addition to litter type climate, vegetation, and indigenous microbes in the surrounding soil affected the development of the bacterial communities in the litter.


Author(s):  
Dabney P. Evans ◽  
Casey D. Xavier Hall ◽  
Raiza Wallace Guimarães da Rocha ◽  
Sandra Marques Prado ◽  
Marcos C. Signorelli

Abstract Purpose The purpose of this mixed-methods triangulation study was to assess the face validity and comprehension of a femicide risk assessment tool, the Danger Assessment-Brazil (DA-Brazil) among women seeking care in a one stop center for abused women in Curitiba, Brazil. Our secondary aim was to assess professionals' perceptions of feasibility for using the DA-Brazil in the same setting. Method Fifty-five women experiencing relationship violence completed the instrument and participated in cognitive interviews about their experience; professionals attending survivors were also interviewed. Results The vast majority of women described the DA-Brazil instrument as being easy to comprehend (n = 41, 73.2%). Nearly half of participants (n = 26, 46.4%) had some kind of question regarding the DA-Brazil calendar, a tool to visualize abuse frequency and severity. Queries aligned with five categories: recollection of dates, scale, relationship status, terminology, and discomfort. Professionals reported that the DA-Brazil instrument would support referral decision-making. Conclusion The overall face validity and comprehension of the DA-Brazil appears to be high. The majority of challenges were around the calendar activity. Professional perceptions of the DA-Brazil suggest a high degree of feasibility for its use in Brazilian healthcare settings. In order for the DA-Brazil to effectively be administered with facilitated support there is a need for training on the best use of the instrument. Accurate assessment of femicide risk is critical in a country like Brazil with high rates of femicide. The DA-Brazil provides a valid assessment of femicide risk and has the potential to trigger early intervention for those at risk.


Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 149
Author(s):  
Subhomita Ghosh Roy ◽  
Charles F. Wimpee ◽  
Stephen A. McGuire ◽  
Timothy J. Ehlinger

Freshwater ecosystems are affected by anthropogenic alterations. Different studies have extensively studied the concentrations of metals, nutrients, and water quality as measurements of pollution in freshwater ecosystems. However, few studies have been able to link these pollutants to bioindicators as a risk assessment tool. This study aimed to examine the potential of two bioindicators, plant ecotoxicological assays and sediment bacterial taxonomic diversity, in ecological risk assessment for six freshwater constructed wetlands in a rapidly urbanizing watershed with diverse land uses. Sediment samples were collected summer, 2015 and 2017, and late summer and early fall in 2016 to conduct plant ecotoxicological assays based on plant (Lepidium, Sinapis and Sorghum) growth inhibition and identify bacterial taxonomical diversity by the 16S rRNA gene sequences. Concentrations of metals such as lead (Pb) and mercury (Hg) (using XRF), and nutrients such as nitrate and phosphate (using HACH DR 2800TM spectrophotometer) were measured in sediment and water samples respectively. Analyses of response patterns revealed that plant and bacterial bioindicators were highly responsive to variation in the concentrations of these pollutants. Hence, this opens up the scope of using these bioindicators for ecological risk assessment in constructed freshwater wetland ecosystems within urbanizing watersheds.


2021 ◽  
Author(s):  
Rajsekhar Adhikary ◽  
Sukhendu Mandal ◽  
Vivekananda Mandal

Abstract Assessment of bacterial community dynamics helps to estimate the endophytic community structure and ecological behaviour imposed by them. Such community composition is essential to understand the molecular interplay that lies between them and the host plants. The present study aims to explore the endophytic bacterial communities and their dynamics in the pre-flowering and post-flowering seasons in the horticulturally important Mango (Mangifera indica L.) and its hemiparasites Loranthus sp., and Macrosolen sp. through a metagenomic approach using the sequence of V3 region of 16S rRNA gene. Bacillus was found to be the most abundant genera, followed by Acinetobacter, and Corynebacterium, which belong to the phyla Firmicutes, Proteobacteria, and Actinobacteria. It has been found that during the post-flowering season, twigs and leaves of mango have lower endophytic bacterial loads. Furthermore, the alpha-diversity indices of the representative genera were highest in Loranthus sp. during the post-flowering seasons of mango. The ecological, taxonomic, and complex correlation studies unravelled that the hemiparasites act as the potent reservoirs of endophytic community throughout the year, and during favourable conditions, these bacterial communities disseminate to the mango plant.


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