Effects of combined treatments of zinc and pH on attached bacterial abundance and activity

1991 ◽  
Vol 37 (7) ◽  
pp. 491-496 ◽  
Author(s):  
Deborah Dean-Ross
Keyword(s):  
Bacterial Community ◽  
Chlorophyll Content ◽  
Diversity Index ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Total Biomass ◽  
Heterotrophic Activity ◽  
Wiener Diversity Index ◽  
Attached Bacteria ◽  
Attached Community

The response of attached bacteria to Zn at three pH levels was studied in outdoor stream mesocosms. Streams containing water from Crooked Lake, Indiana, were dosed with either 0.1 or 0.5 mg Zn/L at ambient pH (pH 8.4), pH 7.0, or pH 5.5. Samples were taken at 2, 5, 10, and 20 days and analyzed for total biomass, chlorophyll content, total bacterial numbers, and heterotrophic activity. All measures of community abundance and activity were highest in the treatment receiving 0.1 mg/L at a pH of 8.4. Treatments at lower pH levels and the higher Zn concentration showed significantly lower biomass, chlorophyll content, and total bacterial numbers. Bacterial heterotrophic activity did not demonstrate a statistically significant response as pH decreased, although it did show a statistically significant decrease at a concentration of 0.5 mg Zn/L. The portion of the bacterial community able to grow on nutrient agar demonstrated adaptation to the increased toxicity of Zn at lower pH levels by an increase in the proportion of bacteria resistant to Zn. In addition, the structure of the culturable bacterial community was altered at low pH, as demonstrated by a reduction in the Shannon–Wiener diversity index. The results indicate that pH can modulate Zn toxicity to the attached community. Key words: attached bacteria, zinc, heavy metal resistance, acid rain, species diversity.

Response of attached bacteria to zinc in artificial streams

1990 ◽  
Vol 36 (8) ◽  
pp. 561-566 ◽  
Author(s):  
Deborah Dean-Ross
Keyword(s):  
Bacterial Community ◽  
Exposure Period ◽  
Wiener Index ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Total Biomass ◽  
Treatment Groups ◽  
Artificial Streams ◽  
Attached Bacteria ◽  
Bacterial Groups

To study the response of natural communities of attached bacteria to Zn, artificial streams were dosed with Zn at levels of 0, 0.01,0.1,0.5, 1.0, and 10.0 mg/L in duplicate treatment groups. Changes in total biomass, chlorophyll a content, total bacterial numbers, and heterotrophic activity were measured over a 5-week exposure period. The adaptation of the culturable bacterial community to Zn was assessed by comparing viable counts on unsupplemented medium with counts on media supplemented with several concentrations of Zn. The structure of that portion of the bacterial community capable of growth on nutrient agar was assessed by characterizing randomly selected colonies with respect to 20 nutritional capabilities and grouping the strains by numerical taxonomy. Streams receiving 0.5, 1.0, and 10.0 mg Zn/L were significantly inhibited with respect to all variables studied when compared with streams receiving 0, 0.01, or 0.1 mg Zn/L. Bacteria developed tolerance to the exposure concentration of Zn but were resistant to higher Zn concentrations. Increasing concentrations of Zn produced alterations in the structure of the culturable bacterial community, resulting in differing assemblages of bacterial groups and a decrease in diversity as measured by the Shannon–Wiener index and rarefaction. These results suggest that streams receiving 0.5 mg Zn/L or more may be adversely impacted. Key words: attached bacteria, zinc, heavy-metal resistance, species diversity.

scholarly journals Effects of Plastic Debris on the Biofilm Bacterial Communities in Lake Water

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1465
Author(s):  
Chao Shen ◽  
Liuyan Huang ◽  
Guangwu Xie ◽  
Yulai Wang ◽  
Zongkai Ma ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Diversity Index ◽  
Plastic Substrate ◽  
Simpson Index ◽  
Plastic Debris ◽  
Plastic Substrates ◽  
Wiener Diversity Index

Increasing discharge of plastic debris into aquatic ecosystems and the worsening ecological risks have received growing attention. Once released, plastic debris could serve as a new substrate for microbes in waters. The complex relationship between plastics and biofilms has aroused great interest. To confirm the hypothesis that the presence of plastic in water affects the composition of biofilm in natural state, in situ biofilm culture experiments were conducted in a lake for 40 days. The diversity of biofilm attached on natural (cobble stones (CS) and wood) and plastic substrates (Polyethylene terephthalate (PET) and Polymethyl methacrylate (PMMA)) were compared, and the community structure and composition were also analyzed. Results from high-throughput sequencing of 16S rRNA showed that the diversity and species richness of biofilm bacterial communities on natural substrate (observed species of 1353~1945, Simpson index of 0.977~0.989 and Shannon–Wiener diversity index of 7.42~8.60) were much higher than those on plastic substrates (observed species of 900~1146, Simpson index of 0.914~0.975 and Shannon–Wiener diversity index of 5.47~6.99). The NMDS analyses were used to confirm the taxonomic significance between different samples, and Anosim (p = 0.001, R = 0.892) and Adonis (p = 0.001, R = 808, F = 11.19) demonstrated that this classification was statistically rigorous. Different dominant bacterial communities were found on plastic and natural substrates. Alphaproteobacterial, Betaproteobacteria and Synechococcophycideae dominated on the plastic substrate, while Gammaproteobacteria, Phycisphaerae and Planctomycetia played the main role on the natural substrates. The bacterial community structure of the two substrates also showed significant difference which is consistent with previous studies using other polymer types. Our results shed light on the fact that plastic debris can serve as a new habitat for biofilm colonization, unlike natural substrates, pathogens and plastic-degrading microorganisms selectively attached to plastic substrates, which affected the bacterial community structure and composition in aquatic environment. This study provided a new insight into understanding the potential impacts of plastics serving as a new habitat for microbial communities in freshwater environments. Future research should focus on the potential impacts of plastic-attached biofilms in various aquatic environments and the whole life cycle of plastics (i.e., from plastic fragments to microplastics) and also microbial flock characteristics using microbial plastics in the natural environment should also be addressed.

scholarly journals Grazing Exclusion, a Choice between Biomass Growth and Species Diversity Maintenance in Beijing—Tianjin Sand Source Control Project

2019 ◽  
Vol 11 (7) ◽  
pp. 1941 ◽  
Author(s):  
Yuzhe Li ◽  
Jiangwen Fan ◽  
Hailing Yu
Keyword(s):  
Species Diversity ◽  
Diversity Index ◽  
Source Control ◽  
Total Biomass ◽  
Above Ground Biomass ◽  
Grazing Exclusion ◽  
Ground Biomass ◽  
Wiener Diversity Index ◽  
Restoration Practices ◽  
Sand Source

Grasslands in northern China form an important ecological barrier that prevents and controls desertification. The Beijing–Tianjin Sand Source Control (BTSSC) Project has been implemented to restore grassland in order to control sand sourced pollution. This study aimed to understand the impacts of four applied restoration practices on the productivity, composition, and species diversity of vegetation communities in the BTSSC Project. The results indicated the following: (1) All the restoration practices tended to increase the height and cover of communities, and the effect was most obvious where grazing was excluded; (2) total biomass (87%), above-ground biomass (164%) and below-ground biomass (58%) only increased consistently when grazing was excluded from the steppe; (3) fenced and grazing exclusion practice significantly increased the abundance of species in communities, but all the practices tended to decrease the evenness of species; and, (4) the correlation analysis revealed that the Shannon–Wiener diversity index, and Pielou evenness index, showed significant negative correlations with the above-ground biomass of grassland communities after restoration, while no significant relationships were shown in reference plots. Our comparison of applied practices in the BTSSC project revealed that grazing exclusion might be a high priority for more successful restoration in this region.

Structure Analysis and Diversity of Bacterial Community and their Resistance Determinants in a Nickel-Contaminated Soil in Southwest Slovakia

2016 ◽  
Vol 24 (1) ◽  
pp. 17-24
Author(s):  
Matej Remenár ◽  
Edita Karelová ◽  
Jana Harichová ◽  
Anna Kamlárová ◽  
Kristína Krčová ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Bacterial Community ◽  
Contaminated Soil ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Bacterial Phyla ◽  
Resistance Determinants ◽  
Final Output ◽  
Heavy Metal Resistant ◽  
Bioremediation Processes

AbstractIn this study we aimed to analyse the structure and diversity of overall bacterial community and its resistance determinants from nickel-contaminated soil in Slovakia by both, cultivation-dependent and independent approaches. The phylogeny was reconstructed using partial sequences of 16S rRNA (16S rDNA) and heavy-metal resistance genes from separated isolates and bacterial clones. A total of 518 bacterial sequences obtained from both, isolates and clones, represented 266 species belonging to 8 bacterial phyla: Acidobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, Firmicutes, Gemmatimonadetes, Proteobacteria (α-, β- and γ-classes), Verrucomicrobia, and one yet unclassified group. In addition, among isolates and clones, 49 different nccA-like genes were found in the final output. Majority of them were assigned to a system of transmembrane metal pumps. Our results demonstrate the fact that the nickel-contaminated soil is able to present very specific heavy-metal resistant bacterial community which can be used in different bioremediation processes.

scholarly journals Comparative Genomic Analysis of 450 Strains of Salmonella enterica Isolated from Diseased Animals

Genes ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1025
Author(s):  
Shaohua Zhao ◽  
Cong Li ◽  
Chih-Hao Hsu ◽  
Gregory H. Tyson ◽  
Errol Strain ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Bacterial Infections ◽  
Genomic Analysis ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Comparative Genomic ◽  
Salmonella Infections ◽  
Antimicrobial Resistance Genes ◽  
Salmonella Pathogenicity Islands ◽  
Shed Light

Salmonella is a leading cause of bacterial infections in animals and humans. We sequenced a collection of 450 Salmonella strains from diseased animals to better understand the genetic makeup of their virulence and resistance features. The presence of Salmonella pathogenicity islands (SPIs) varied by serotype. S. Enteritidis carried the most SPIs (n = 15), while S. Mbandaka, S. Cerro, S. Meleagridis, and S. Havana carried the least (n = 10). S. Typhimurium, S. Choleraesuis, S. I 4,5,12:i:-, and S. Enteritidis each contained the spv operon on IncFII or IncFII-IncFIB hybrid plasmids. Two S. IIIa carried a spv operon with spvD deletion on the chromosome. Twelve plasmid types including 24 hybrid plasmids were identified. IncA/C was frequently associated with S. Newport (83%) and S. Agona (100%) from bovine, whereas IncFII (100%), IncFIB (100%), and IncQ1 (94%) were seen in S. Choleraesuis from swine. IncX (100%) was detected in all S. Kentucky from chicken. A total of 60 antimicrobial resistance genes (ARGs), four disinfectant resistances genes (DRGs) and 33 heavy metal resistance genes (HMRGs) were identified. The Salmonella strains from sick animals contained various SPIs, resistance genes and plasmid types based on the serotype and source of the isolates. Such complicated genomic structures shed light on the strain characteristics contributing to the severity of disease and treatment failures in Salmonella infections, including those causing illnesses in animals.

scholarly journals Heavy Metal Tolerance Trend in Extended-Spectrum β-Lactamase Encoding Strains Recovered from Food Samples

2021 ◽  
Vol 18 (9) ◽  
pp. 4718
Author(s):  
Kashaf Junaid ◽  
Hasan Ejaz ◽  
Iram Asim ◽  
Sonia Younas ◽  
Humaira Yasmeen ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Food Samples ◽  
Esbl Production ◽  
Extended Spectrum ◽  
Retail Food ◽  
Esbl Producers

This study evaluates bacteriological profiles in ready-to-eat (RTE) foods and assesses antibiotic resistance, extended-spectrum β-lactamase (ESBL) production by gram-negative bacteria, and heavy metal tolerance. In total, 436 retail food samples were collected and cultured. The isolates were screened for ESBL production and molecular detection of ESBL-encoding genes. Furthermore, all isolates were evaluated for heavy metal tolerance. From 352 culture-positive samples, 406 g-negative bacteria were identified. Raw food samples were more often contaminated than refined food (84.71% vs. 76.32%). The predominant isolates were Klebsiella pneumoniae (n = 76), Enterobacter cloacae (n = 58), and Escherichia coli (n = 56). Overall, the percentage of ESBL producers was higher in raw food samples, although higher occurrences of ESBL-producing E. coli (p = 0.01) and Pseudomonas aeruginosa (p = 0.02) were observed in processed food samples. However, the prevalence of ESBL-producing Citrobacter freundii in raw food samples was high (p = 0.03). Among the isolates, 55% were blaCTX-M, 26% were blaSHV, and 19% were blaTEM. Notably, heavy metal resistance was highly prevalent in ESBL producers. These findings demonstrate that retail food samples are exposed to contaminants including antibiotics and heavy metals, endangering consumers.

scholarly journals Genome-Driven Discovery of Enzymes with Industrial Implications from the Genus Aneurinibacillus

2021 ◽  
Vol 9 (3) ◽  
pp. 499
Author(s):  
Majid Rasool Kamli ◽  
Nada A. Y. Alzahrani ◽  
Nahid H. Hajrah ◽  
Jamal S. M. Sabir ◽  
Adeel Malik
Keyword(s):  
Heavy Metal ◽  
Enzyme Activities ◽  
Heavy Metal Resistance ◽  
Industrial Applications ◽  
Metal Resistance ◽  
The Family ◽  
Antiviral Activities ◽  
Genome Level ◽  
Genome Analyses ◽  
Unique Species

Bacteria belonging to the genus Aneurinibacillus within the family Paenibacillaceae are Gram-positive, endospore-forming, and rod-shaped bacteria inhabiting diverse environments. Currently, there are eight validly described species of Aneurinibacillus; however, several unclassified species have also been reported. Aneurinibacillus spp. have shown the potential for producing secondary metabolites (SMs) and demonstrated diverse types of enzyme activities. These features make them promising candidates with industrial implications. At present, genomes of 9 unique species from the genus Aneurinibacillus are available, which can be utilized to decipher invaluable information on their biosynthetic potential as well as enzyme activities. In this work, we performed the comparative genome analyses of nine Aneurinibacillus species representing the first such comprehensive study of this genus at the genome level. We focused on discovering the biosynthetic, biodegradation, and heavy metal resistance potential of this under-investigated genus. The results indicate that the genomes of Aneurinibacillus contain SM-producing regions with diverse bioactivities, including antimicrobial and antiviral activities. Several carbohydrate-active enzymes (CAZymes) and genes involved in heavy metal resistance were also identified. Additionally, a broad range of enzyme classes were also identified in the Aneurinibacillus pan-genomes, making this group of bacteria potential candidates for future investigations with industrial applications.

scholarly journals Effects of Ecological Restoration Using Non-Native Mangrove Kandelia obovata to Replace Invasive Spartina alterniflora on Intertidal Macrobenthos Community in Maoyan Island (Zhejiang, China)

2021 ◽  
Vol 9 (8) ◽  
pp. 788
Author(s):  
Qiuxuan Wang ◽  
Carlos Duarte ◽  
Li Song ◽  
George Christakos ◽  
Susana Agusti ◽  
...  
Keyword(s):  
Community Structure ◽  
Ecological Restoration ◽  
Spartina Alterniflora ◽  
Diversity Index ◽  
Invasion History ◽  
Kandelia Obovata ◽  
Wiener Diversity Index ◽  
Significant Difference ◽  
Spatial Differences ◽  
Average Biomass

Spartina alterniflora has extensively invaded the coastline of China, including in Maoyan Island of Zhejiang Province. Ecological restoration has been conducted using non-native mangrove Kandelia obovata to replace S. alterniflora in an attempt to restore the impacted intertidal zones. To illustrate the ecological effectiveness of the restoration projects, macrobenthos communities were studied among different habitats within the restored areas, including one non-restored S. alterniflora marsh (SA) and three differently-aged restored K. obovata stands planted in 2003, 2009, and 2011 respectively (KF14, KF8, and KF6). Besides, one unvegetated mudflat (MF) adjacent to the non-restored S. alterniflora marsh and one K. obovata forest transplanted in 2006 (RKF) at a previously barren mudflat without invasion history of S. alterniflora were set as reference sites. A total of 69 species of macrobenthos were collected from Maoyan Island, and the species richness was dominated by gastropoda (23 species), polychaeta (18 species), and malacostraca (16 species). There was no significant difference between the six sites in terms of the abundance of macrobenthos, with the average values of abundance peaking in KF6 (734.7 ind m−2) and being lowest in RKF (341.3 ind m−2). The six sites had significant differences in terms of the biomass of macrobenthos. The KF8 site contained the highest average biomass (168.3 g m−2), whereas the MF site had the lowest (54.3 g m−2). The Shannon-Wiener diversity index and Pielou’s evenness index of the macrobenthos did not exhibit significant differences among the six sites. However, the results of permutational multivariate analysis of variance (PERMANOVA) revealed significant spatial differences in the macrobenthos community structure between the sites. Since KF14 shared a similar macrobenthos community structure with RKF, while representing a strikingly different structure from SA, we infer that ecological restoration using K. obovata can restore the macrobenthos community to resemble to a normally planted K. obovata forest about 15 years after restoration.

scholarly journals Retromobilization of heavy metal resistance genes in unpolluted and heavy metal polluted soil

1995 ◽  
Vol 18 (3) ◽  
pp. 191-203 ◽  
Author(s):  
Eva M. Top ◽  
Helene Rore ◽  
Jean-Marc Collard ◽  
Veerle Gellens ◽  
Galina Slobodkina ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Resistance Genes ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Polluted Soil

scholarly journals Replication of Staphylococcal Multiresistance Plasmids

2000 ◽  
Vol 182 (8) ◽  
pp. 2170-2178 ◽  
Author(s):  
Neville Firth ◽  
Sumalee Apisiridej ◽  
Tracey Berg ◽  
Brendon A. O'Rourke ◽  
Steve Curnock ◽  
...  
Keyword(s):  
Sequence Similarity ◽  
Heavy Metal Resistance ◽  
Metal Resistance ◽  
Replication Initiation ◽  
Conjugative Plasmid ◽  
Rolling Circle ◽  
Segregational Stability ◽  
Structural And Functional Properties ◽  
Resistance Plasmids ◽  
Genes Encoding

ABSTRACT Based on structural and functional properties, three groups of large staphylococcal multiresistance plasmids have been recognized, viz., the pSK1 family, pSK41-like conjugative plasmids, and β-lactamase–heavy-metal resistance plasmids. Here we describe an analysis of the replication functions of a representative of each of these plasmid groups. The replication initiation genes from theStaphylococcus aureus plasmids pSK1, pSK41, and pI9789::Tn552 were found to be related to each other and to the Staphylococcus xylosus plasmid pSX267 and are also related to rep genes of several plasmids from other gram-positive genera. Nucleotide sequence similarity between pSK1 and pI9789::Tn552 extended beyond theirrep genes, encompassing upstream divergently transcribed genes, orf245 and orf256, respectively. Our analyses revealed that genes encoding proteins related to the deducedorf245 product are variously represented, in several types of organization, on plasmids possessing six seemingly evolutionarily distinct types of replication initiation genes and including both theta-mode and rolling-circle replicons. Construction of minireplicons and subsequent functional analysis demonstrated that orf245is required for the segregational stability of the pSK1 replicon. In contrast, no gene equivalent to orf245 is evident on the conjugative plasmid pSK41, and a minireplicon encoding only the pSK41 rep gene was found to exhibit a segregational stability approaching that of the parent plasmid. Significantly, the results described establish that many of the large multiresistance plasmids that have been identified in clinical staphylococci, which were formerly presumed to be unrelated, actually utilize an evolutionarily related theta-mode replication system.

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