Cheap Materials to Clean Heavy Metal Polluted Waters

Abstract BackgroundAnopheles arabiensis (a member of the An. gambiae species complex) is a major vector of malaria. These mosquitoes typically breed in clean bodies of water, but can also utilise polluted waters. Although this expands their breeding range, adaptation to breeding in polluted waters necessitates coping with a large amount of environmental stress in the form of exposure to heavy metal pollutants. Environmental stress can induce heritable changes to an organism without altering the basal genetic code. This occurs by rapid changes in the regulatory elements associated with nucleic acids that result in changes in patterns of gene expression and silencing. This is known as epigenetic regulation. There is currently little information on epigenetic regulation in An. arabiensis. The aim of this study was to examine whether exposure to metal pollutants at the larval stage induced alterations of epigenetic markers resulting in phenotypic changes in insecticide susceptible and resistant laboratory strains of An. arabiensis. ResultsThere was a marked difference in the phenotypic response in adult mosquitoes of the insecticide susceptible strain compared to that of its’ resistant counterpart. The susceptible strain showed reduced fertility and fecundity in response to epigenetic manipulation. For males and females of the resistant strain, exposure to nucleic acid modifying drugs typically increased their tolerance to insecticides. In the insecticide susceptible strain, regulatory signals associated with gene silencing were increased, while those associated with gene expression were reduced in response to heavy metal exposure. By contrast, the insecticide resistant strain showed a decrease in signatures associated with gene silencing as well as an increase in signatures associate with chromatin remodelling. ConclusionsLarval exposure to heavy metal contaminants can result in heritable changes in gene expression. These data suggest that exposure to the same pollutants can result in different biological outcomes in insecticide susceptible and resistant adult An. arabiensis, and that these changes are reflected in their respective global? epigenetic signatures.

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Glauconitic greensand: A possible filter of heavy metal cations from polluted waters

Environmental Geology ◽

10.1007/bf02380487 ◽

1978 ◽

Vol 2 (4) ◽

pp. 215-221 ◽

Cited By ~ 11

Author(s):

Nenad Spoljaric ◽

William A. Crawford

Keyword(s):

Heavy Metal ◽

Metal Cations ◽

Heavy Metal Cations ◽

Polluted Waters

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Short-term changes in phytoplankton assemblages and their potential for heavy metal bioaccumulation – a laboratory study

Oceanological and Hydrobiological Studies ◽

10.1515/ohs-2018-0025 ◽

2018 ◽

Vol 47 (3) ◽

pp. 260-274 ◽

Cited By ~ 1

Author(s):

Abd-Ellatif M. Hussian ◽

Ahmed M. Abd El-Monem ◽

Agnieszka Napiórkowska-Krzebietke ◽

Naser S. Flefil

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Abundant Species ◽

Metal Bioaccumulation ◽

Phytoplankton Assemblages ◽

Iron And Zinc ◽

Heavy Metal Bioaccumulation ◽

Aulacoseira Granulata ◽

Polluted Waters ◽

Egyptian Lakes

Abstract This study focused on phytoplankton changes in polluted waters of Lake Manzala and the assessment of heavy metal bioaccumulation capacity during the 15-day laboratory experiment. Phytoplankton samples were analyzed every day and the concentration of zinc, iron and lead in water, in phytoplankton and in filtrate – every fifth day of the experiment. Significantly higher phytoplankton abundance was recorded in water from the El-Boom station (basin I) compared to the New Bahr El-Baqar drain (basin II), followed by distinct differences in its composition and chlorophyll content. However, the most abundant species were the same in both basins, i.e. Chroococcus minor, Microcystis aeruginosa, Actinoptychus octonarius, Aulacoseira granulata, Pantocsekiella ocellata, Kirchneriella obesa and Nephrocytium limneticum. Water in basin I was more polluted with heavy metals compared to basin II. Basin I was characterized by the dominance of cyanobacteria and high relative abundance of chlorophytes compared to basin II, where either cyanobacteria and/or diatoms dominated in the phytoplankton. In the former basin, the highest uptake factors (UFs) were recorded for iron and zinc and the lowest UF for lead. In basin II, the highest UF was determined for zinc, but relatively high UFs were recorded also for iron and lead. The presented results suggest that phytoplankton can contribute to natural biosorbents of heavy metals in Egyptian lakes.

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Habitat Association of Klebsiella Species

Infection Control ◽

10.1017/s0195941700062603 ◽

1985 ◽

Vol 6 (2) ◽

pp. 52-58 ◽

Cited By ~ 111

Author(s):

Susan T. Bagley

Keyword(s):

Drinking Water ◽

Gastrointestinal Tract ◽

Surface Waters ◽

Industrial Effluents ◽

Opportunistic Pathogen ◽

Habitat Associations ◽

Habitat Association ◽

Klebsiella Species ◽

Almost All ◽

Polluted Waters

AbstractThe genus Klebsiella is seemingly ubiquitous in terms of its habitat associations. Klebsiella is a common opportunistic pathogen for humans and other animals, as well as being resident or transient flora (particularly in the gastrointestinal tract). Other habitats include sewage, drinking water, soils, surface waters, industrial effluents, and vegetation. Until recently, almost all these Klebsiella have been identified as one species, ie, K. pneumoniae. However, phenotypic and genotypic studies have shown that “K. pneumoniae” actually consists of at least four species, all with distinct characteristics and habitats. General habitat associations of Klebsiella species are as follows: K. pneumoniae—humans, animals, sewage, and polluted waters and soils; K. oxytoca—frequent association with most habitats; K. terrigena— unpolluted surface waters and soils, drinking water, and vegetation; K. planticola—sewage, polluted surface waters, soils, and vegetation; and K. ozaenae/K. rhinoscleromatis—infrequently detected (primarily with humans).

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Complementary Z-Contrast Imaging and Digital Image Processing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100118394 ◽

1985 ◽

Vol 43 ◽

pp. 304-305

Author(s):

K. N. Colonna ◽

G. Oliphant

Keyword(s):

Image Processing ◽

Heavy Metal ◽

Digital Image Processing ◽

Digital Image ◽

Biological Tissue ◽

Biological Imaging ◽

Tissue Preparation ◽

Contrast Imaging ◽

Imaging Tool ◽

Z Contrast

Harmonious use of Z-contrast imaging and digital image processing as an analytical imaging tool was developed and demonstrated in studying the elemental constitution of human and maturing rabbit spermatozoa. Due to its analog origin (Fig. 1), the Z-contrast image offers information unique to the science of biological imaging. Despite the information and distinct advantages it offers, the potential of Z-contrast imaging is extremely limited without the application of techniques of digital image processing. For the first time in biological imaging, this study demonstrates the tremendous potential involved in the complementary use of Z-contrast imaging and digital image processing.Imaging in the Z-contrast mode is powerful for three distinct reasons, the first of which involves tissue preparation. It affords biologists the opportunity to visualize biological tissue without the use of heavy metal fixatives and stains. For years biologists have used heavy metal components to compensate for the limited electron scattering properties of biological tissue.

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Recent Progress In High-Resolution Shadowing For Biological Transmission Electron Microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100181300 ◽

1990 ◽

Vol 48 (1) ◽

pp. 510-511 ◽

Cited By ~ 1

Author(s):

Heinz Gross ◽

Katarina Krusche ◽

Peter Tittmann

Keyword(s):

Heavy Metal ◽

High Resolution ◽

Freeze Drying ◽

Atmospheric Conditions ◽

Vacuum Equipment ◽

Transmission Electron ◽

Gas Atmosphere ◽

Gas Molecules ◽

Residual Gas ◽

Backing Layer

Freeze-drying followed by heavy metal shadowing is a long established and straight forward approach to routinely study the structure of dehydrated macromolecules. Very thin specimens such as isolated membranes or single macromolecules are directly adsorbed on C-coated grids. After rapid freezing the grids are transferred into a suitable vacuum equipment for freeze-drying and heavy metal shadowing.To improve the resolution power of shadowing films we introduced shadowing at very low specimen temperature (−250°C). To routinely do that without the danger of contamination we developed in collaboration with Balzers an UHV (p≤10-9 mbar) machine (BAF500K, Fig.2). It should be mentioned here that at −250°C the specimen surface acts as effective cryopump for practically all impinging residual gas molecules from the residual gas atmosphere.Common high resolution shadowing films (Pt/C, Ta/W) have to be protected from alterations due to air contact by a relatively thick C-backing layer, when transferred via atmospheric conditions into the TEM. Such an additional C-coat contributes disturbingly to the contrast at high resolution.

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