This paper examines the bio-derived stabilization of sand-only or sand-plus-silt soils using an extracted bacterial enzyme application to achieve induced calcite precipitation (ICP). As compared to ...conventional microbial induced calcite precipitation (MICP) methods, which use intact bacterial cells, this strategy that uses free urease catalysts to secure bacterial enzyme–induced calcite precipitation (BEICP) appears to offer an improved means of bio-stabilizing silty-sand soils as compared to that of MICP processing. Several benefits may possibly be achieved with this BEICP approach, including bio-safety, environmental, and geotechnical improvements. Notably, the BEICP bio-stabilization results presented in this paper demonstrate (i) higher rates of catalytic urease activity, (ii) a wider range of application with sand-plus-silt soil applications bearing low-plasticity properties, and (iii) the ability to retain higher levels of soil permeability after BEICP processing. Comparative BEICP versus MICP results for sand-only systems are presented, along with BEICP-based results for stabilized soil mixtures at 90:10 and 80:20 percentile sand:silt ratios. This BEICP method’s ability to obtain unconfined compressive strength results in excess of 1000 kPa with sand-plus-silt soil mixtures is particularly noteworthy.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
As nanoparticles (NPs) enter into biological systems, they are immediately exposed to a variety and concentration of proteins. The physicochemical interactions between proteins and NPs are influenced ...by the surface properties of the NPs. To identify the effects of NP surface heterogeneity, the interactions between bovine serum albumin (BSA) and gold NPs (AuNPs) with similar chemical composition but different surface structures were investigated. Different interaction modes and BSA conformations were studied by dynamic light scattering, circular dichroism spectroscopy, fluorescence quenching and isothermal titration calorimetry (ITC). Depending on the surface structure of AuNPs, BSA seems to adopt either a “side-on” or an “end-on” conformation on AuNPs. ITC demonstrated that the adsorption of BSA onto AuNPs with randomly distributed polar and nonpolar groups was primarily driven by electrostatic interaction, and all BSA were adsorbed in the same process. The adsorption of BSA onto AuNPs covered with alternating domains of polar and nonpolar groups was a combination of different interactions. Overall, the results of this study point to the potential for utilizing nanoscale manipulation of NP surfaces to control the resulting NP–protein interactions.
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IJS, KILJ, NUK, PNG, UL, UM
Conjugation of catabolic plasmids in contaminated environments is a naturally occurring horizontal gene transfer phenomenon, which could be utilized in genetic bioaugmentation. The potentially ...important parameters for genetic bioaugmentation include gene regulation of transferred catabolic plasmids that may be controlled by the genetic characteristics of transconjugants as well as environmental conditions that may alter the expression of the contaminant-degrading phenotype. This study showed that both genomic guanine–cytosine contents and phylogenetic characteristics of transconjugants were important in controlling the phenotype functionality of the TOL plasmid. These genetic characteristics had no apparent impact on the stability of the TOL plasmid, which was observed to be highly variable among strains. Within the environmental conditions tested, the addition of glucose resulted in the largest enhancement of the activities of enzymes encoded by the TOL plasmid in all transconjugant strains. Glucose (1 g/L) enhanced the phenotype functionality by up to 16.4 (±2.22), 30.8 (±7.03), and 90.8 (±4.56)-fold in toluene degradation rates, catechol 2,3-dioxygenase enzymatic activities, and
xylE
gene expression, respectively. These results suggest that genetic limitations of the expression of horizontally acquired genes may be overcome by the presence of alternate carbon substrates. Such observations may be utilized in improving the effectiveness of genetic bioaugmentation.
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CEKLJ, DOBA, EMUNI, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK
Reliable access to safe water is essential for health, wellbeing, and the livelihoods of people. However, water security innovations benefit when engineering and geoscience decisions consider ...systemic human, social, and organizational realities, needs, and goals. Indeed, true innovation that leads to water security requires intensively inclusive and iterative processes to occur at multiple scales of analysis across diverse sciences—for this, expertise and knowledge across the varied sciences is essential to facilitate such convergent, transdisciplinary research. Here, we articulate our perspective for identifying points of intersection and working across disciplinary boundaries to address water crises. Our perspective takes a multidimensional view of community, organization, family, and individual resilience in the face of natural and human hazards. It builds upon previous models of cumulative water related risk by nuancing the relationships amongst levels of analysis, and expanding the idea of cumulative impacts to include interactive impacts (e.g., buffering, enhancing, effects and other moderators), mediated effects (i.e., mechanisms of impact), as well as additive and suppressive linkages amongst risk and protective factors.
In the bacterial enzyme-induced calcite precipitation (BEICP) technique for biocementation, the spatial distribution of adsorbed and catalytically active urease dictates the location where calcium ...carbonate precipitation and resulting cementation will occur. This study investigated the relationships between the amount of urease and total bacterial proteins adsorbed, the retained enzymatic activity of adsorbed urease, and the overall loss of activity upon adsorption, and how these relationships are influenced by changes in soil surface chemistry. In soils with hydrophobic contents higher than 20% (w/w) ratio, urease was preferentially adsorbed compared to the total amount of proteins present in the crude bacterial protein extract. Conversely, adsorption of urease onto silica sand and soil mixtures, including iron-coated sand, was much lower compared to the total proteins. Higher levels of urease activity were retained in hydrophobic-containing samples, with urease activity decreasing with lower hydrophobic content. These observations suggest that the surface manipulation of soils, such as treatments to add hydrophobicity to soil surfaces, can potentially be used to increase the activity of adsorbed urease to improve biocementation outcomes.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Pathogen resistance against common disinfectants in drinking water treatment could have serious public health implications, particularly in potable water reuse. Frequent disinfection in potable water ...reuse has a potential to facilitate resistance development. This study investigated resistance development in
Escherichia coli
against repeated monochloramine and ferrate disinfection.
E. coli
cultures repeatedly treated with monochloramine developed resistance after 12 + treatment rounds, whereas repeated ferrate disinfection did not lead to resistance development. Monochloramine induced cells into the viable but nonculturable (VBNC) state in initial disinfection rounds; however, repeated monochloramine treatment caused increases in culturability, which corresponded to decreases in the fraction of VBNC cells post-disinfection. The cumulative number of disinfection episodes (∼12 times) rather than treatment frequency (e.g., every 48, 96, or 144 h) played a critical role in resistance development against monochloramine. In addition to preventing resistance, ferrate effectively inactivated (>3-log
10
) the evolved monochloramine-stressed cultures, suggesting that the evolutionary adaptations against monochloramine were ineffective against ferrate. The lack of resistance against ferrate renders it a promising disinfection agent that deserves further assessment. This work’s findings demonstrate that repeated disinfection coupled with the type of applied disinfectant can influence bacterial resistance development. Therefore, current and future water disinfection schemes, especially within potable water reuse, need regular monitoring to evaluate the resistance profile of pathogenic bacteria.
Three dimensional printing has emerged as a widely acceptable strategy for the fabrication of mammalian cell laden constructs with complex microenvironments for tissue engineering and regenerative ...medicine. More recently 3D printed living materials containing microorganisms have been developed and matured into living biofilms. The potential for engineered 3D biofilms as in vitro models for biomedical applications, such as antimicrobial susceptibility testing, and environmental applications, such as bioleaching, bioremediation, and wastewater purification, is extensive but the need for an in‐depth understanding of the structure–function relationship between the complex construct and the microorganism response still exists. This review discusses 3D printing fabrication methods for engineered biofilms with specific structural features. Next, it highlights the importance of bioink compositions and 3D bioarchitecture design. Finally, a brief overview of current and potential applications of 3D printed biofilms in environmental and biomedical fields is discussed.
This review discusses 3D printing fabrication methods for engineered biofilms with specific structural features. Next, it highlights the importance of bioink compositions and 3D bio architecture design. Finally, a brief overview of current and potential applications of 3D printed biofilms in environmental and biomedical fields is discussed.
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FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
Consistent and accurate measurement of public perceptions of water quality is useful for understanding water use behaviors, policy development/support, and community engagement, all essential for ...sustainable water management. Toward consistent and accurate measurement, we refined and examined the initial psychometric properties of a Water Quality Perception Scale (WQPS). In this study, we report an exploratory factor analysis (EFA) with 18 items on a group of respondents ( N = 154), which identified one primary factor, ‘Individual Water Quality Perception,’ consisting of 13 items and two additional factors represented by the remaining 5 items. Subsequently, a confirmatory factor analysis (CFA) was performed with ( n = 147 participants), including both original ( n = 74 assessed at a separate time from their original assessment) and new participants ( n = 73). The results of the CFA affirmed the initial loadings of the 13-item WQPS in a single factor. The scale demonstrated internal consistency, with coefficients of 0.93 and 0.90 (Cronbach’s alpha) in the two samples, and the measure showed convergent validity with the Household Water Insecurity Experiences Scale (HWISE), ( r = −0.41 and −0.49 in the respective samples). This scale holds promise toward consistent and accurate measurement instrument for researching public perceptions of water quality, guiding policy and public initiatives to improve water management strategies. Avenues for further development and use are discussed.
Several studies have suggested that global DNA methylation in circulating white blood cells (WBC) is associated with breast cancer risk.
To address conflicting results and concerns that the findings ...for WBC DNA methylation in some prior studies may reflect disease effects, we evaluated the relationship between global levels of WBC DNA methylation in white blood cells and breast cancer risk in a case-control study nested within the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO) cohort. A total of 428 invasive breast cancer cases and 419 controls, frequency matched on age at entry (55-59, 60-64, 65-69, ≥70 years), year of entry (on/before September 30, 1997, on/after October 1, 1997) and period of DNA extraction (previously extracted, newly extracted) were included. The ratio of 5-methyl-2' deoxycytidine 5-mdC to 2'-deoxyguanine dG, assuming dG = 5-mdC + 2'-deoxycytidine dC (%5-mdC), was determined by liquid chromatography-electrospray ionization-tandem mass spectrometry, an especially accurate method for assessing total genomic DNA methylation.
Odds ratio (OR) estimates and 95% confidence intervals (CI) for breast cancer risk adjusted for age at entry, year of entry, and period of DNA extraction, were 1.0 (referent), 0.89 (95% CI, 0.6-1.3), 0.88 (95% CI, 0.6-1.3), and 0.84 (95% CI, 0.6-1.2) for women in the highest compared to lowest quartile levels of %5md-C (p for trend = .39). Effects did not meaningfully vary by time elapsed from WBC collection to diagnosis.
These results do not support the hypothesis that global DNA hypomethylation in WBC DNA is associated with increased breast cancer risk prior to the appearance of clinical disease.
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