Integrative Conjugative Elements (ICE's) of the SXT/R391 family have largely been detected in clinical or environmental isolates of Gammaproteobacteria, particularly Vibrio and Proteus species. As ...wastewater treatment plants accumulate a large and diverse number of such species, we examined raw water samples taken from a municipal wastewater treatment plant initially using SXT/R391 family integrase gene-specific PCR probes to detect the presence of such elements in a directed approach. A positive amplification occurred over a full year period and a subsequent Restriction Fragment Length Polymorphism (RFLP) analysis revealed a very limited diversity in the treatment plant examined. Samples demonstrating positive amplification were cultured using Vibrio and Proteus selective media and PCR amplification tracking was utilized to monitor SXT/R391-ICE family containing strains. This screening procedure resulted in the isolation and identification of a Proteus mirabilis strain harbouring an ICE. Whole-genome sequencing of this ICE containing strain using Illumina sequencing technology revealed a novel 81 kb element that contained 75 open reading frames on annotation but contained no antibiotic or metal resistance determinants. Comparative genomics revealed the element contained a conserved ICE core with one of the insertions containing a novel bacteriophage defence mechanism. This directed isolation suggests that ICE elements are present in the environment without apparent selective pressure but may contain adaptive functions allowing survival in particular environments such as municipal wastewater which are reservoirs for large bacterial phage populations.
Natural organic matter poses an increasing challenge to water managers because of its potential adverse impacts on water treatment and distribution, and subsequently human health. Projections were ...made of impacts of climate change on dissolved organic carbon (DOC) in the primarily agricultural Boyne catchment which is used as a potable water supply in Ireland. The results indicated that excluding a potential rise in extreme precipitation, future projected loads are not dissimilar to those observed under current conditions. This is because projected increases in DOC concentrations are offset by corresponding decreases in precipitation and hence river flow. However, the results presented assume no changes in land use and highlight the predicted increase in DOC loads from abstracted waters at water treatment plants.
Display omitted
•Potential impacts of climate change on NOM were projected.•Results show future behaviours are similar to current conditions.•Projected increases are offset by parallel decreases in precipitation and flow.
The mobilisation and impact of roadway runoff on dairy farms has been established as a sub-component of the nutrient transfer continuum. It is acknowledged that fresh nutrient sources deposited on ...roadways dominate runoff and recent work has shown that available phosphorus (P) in roadway substrates is also an important source component. The objectives of this study were to understand spatial and temporal available P concentrations in roadway substrate (aggregate and soil mix) across dairy and beef farms during the open (February–October, when cows use the roadway network and fields) and closed (November–January, when cows were housed) periods and identify locations which could be considered critical source areas (CSA). For the study, roadway substrate samples were taken at 18 locations on each farm, across eight sampling periods, and were analysed for available P. Results showed that mean available P concentrations (Morgan’s P) in the sampling locations ranged from 15.9 to 101.4 mg L -1 for the Dairy Farm, from 4.1 to 59.4 mg L -1 for Beef Farm 1 and from 6.3 to 23.2 mg L -1 for Beef Farm 2. In open period, the results showed that mean available P concentrations were 75.4 ± 30.9, 14.9 ± 3.2 and 13.4 ± 2.5 mg L -1 for the Dairy Farm, Beef Farm 1 and Beef Farm 2, respectively. In closed period, the mean available P were 40.3 ± 17.2, 10.4 ± 1.0 and 9.8 ± 0.2 mg L -1 for Dairy Farm, Beef Farm 1 and Beef Farm 2, respectively. Overall, P concentrations on the Dairy Farm roadways was up to 4 times greater than that in the Beef Farms’ roadways. Compared to soils in adjacent fields, P concentrations in the Dairy and Beef Farms roadways was up-to 7 and 2 times higher, respectively. Critical roadway sections that required mitigation were two in the Dairy Farm, one in Beef Farm 1 and two in Beef Farm 2. In addition to fresh faeces and urine (i.e., dominant source of nutrients in farm roadways), this study showed that nutrient enriched roadway materials are a labile P source. Thus, future mitigation of roadway runoff must consider all roadway nutrient sources, including livestock fresh excreta as well as used roadway surface materials.
Internal farm roadways are connectors within agricultural landscapes, which act as sub-components of the nutrient transfer continuum (NTC). On dairy farms, roadway surface runoff dissolved and ...particulate phosphorus (P) sources stem from a combination of cow excreta deposited at locations that impede animal flow, soil deposited from cow hooves or machinery tyres, run-on from up-gradient fields, public roadways or farmyards and incidental spill of organic/inorganic fertilizers. The present study investigates the storage and potential release of P from the underlying roadway material (i.e. composite of soil and stone aggregates) as this source component is not considered in the NTC framework or documented in the literature. Herein, farm roadway materials were sampled (to 1 cm depth) at 17 locations avoiding fresh cow excreta. Multiple location types were selected e.g. straight roadway sections, roadway junctions, before and adjacent standoff areas associated with cattle underpasses, with all locations varying in distance from the farmyard. Roadway samples were analysed for phosphorus (P) and metals (Al, B, Ca, Co, Cu, Fe, K, Mg, and Mn) content. Results showed that the soil component of roadway materials are significant P legacy sources and are in themselves a P-storage component that merits inclusion in the NTC framework. All sampled locations, when compared with fresh roadway stone aggregates or surrounding fields, had highly elevated P with plant available Morgans P > 8 mg L
-1
(Index 4, ranging from 10 – 110 mg L
-1
). Sampling points within 100 m of the farmyard together with roadway junctions and underpasses beyond this distance had highest P concentrations. Critical source areas, where source, mobilisation and transport of P to waters coincided, formed at three locations. Possible mitigation measures are a) divert roadway runoff into fields using low-cost surface water breaks, b) disconnect cattle underpass tanks from receiving waters and c) change roadway infrastructure to improve cow flow and minimise source build-up. Future research should examine P loads in runoff from roadway sections across farm typologies and roadway material types.
Display omitted
•KOH modified Ascophyllum nodosum seaweed hydrochar is an effective V(V) adsorbent;•Weak binding of V(V) to the hydrochar indicates a reversible adsorption process;•The impact of ...co-existing cations had negligible impact on uptake of V(V);•Desorption and re-adsorption results indicate reusable potential for V(V) recovery.
Vanadium exists as a mobile and toxic trace metal in many alkaline residue leachates. Its removal and recovery not only reduces a global environmental risk but is also critical to the emergence of innovative technologies and the circular economy. In parallel, the use of treated biomass feedstock is receiving increased attention as a low cost adsorbent for toxic metals in wastewater. This study investigated the adsorption of Vanadium (V) from aqueous solution by KOH modified seaweed (Ascophyllum nodosum) hydrochar (HCKOH). The results showed that HCKOH is an effective V(V) adsorbent, achieving maximum uptake of 12.3 mg g−1 at solution pH 4, 60 min contact time and temperature 293 K. The kinetics followed a pseudo second order model with film diffusion controlling the overall adsorption rate. The type I adsorption isotherm was well fitted to a Langmuir model (qm = 12.3 mg g-1, R2 = 0.970, RMSE = 0.66) and a thermodynamic study indicated that the V(V) adsorption was both exothermic and spontaneous. The low enthalpy change (-10.97 kJ mol−1) indicated a weak binding of V(V) to HCKOH pointing to the possibility of V recovery. The impact of co-existing cations on V(V) uptake was negligible for Na(I) and Ga (III) but was reduced slightly for Al(III). Desorption and re-adsorption results (3 cycles) indicated that HCKOH has reusable potential to remove and recover V(V) from waste leachates.
Adsorption studies were carried out on a red mud modified sawdust biochar material to assess its capacity in the removal of vanadium (V) from aqueous solution. In this study, a number of parameters ...which can potentially influence V(V) adsorption were investigated including equilibrium V(V) solution concentration, contact time for effective V(V) removal, temperature of the adsorption process, solution pH and ionic strength. The uptake of V(V) was shown to be heavily influenced by solution pH with maximum uptake (16.45 mg g−1) achieved in the pH range of 3.5 - 5.5. The adsorption process was best described by the Langmuir model. The kinetics of the adsorption process indicated that V(V) uptake occurred within 60 min of contact and that pseudo-second order kinetics best described the kinetics of the overall adsorption process. There was a clear increase in V(V) uptake with increasing temperature (range 293–343 K) indicating an endothermic adsorption process and the level of uptake remained largely unchanged at solution salt concentrations of up to 0.1 M NaCl and competing cation concentrations of up to 2000 mg L-1 of sodium and 200 mg L-1 aluminium. The relatively weak interaction between V(V) and the modified biochar surface may indicate a possibility of recovery of the bound V(V) and subsequent regeneration of the adsorbent.
Methamphetamine use is a growing public health concern nationwide. Suicide is the second leading cause of death in 2019 for US citizens aged 10-14 years and 25-34 years and is also a significant ...public health concern. Understanding the intersection of methamphetamine use and suicidal ideation (SI) is necessary to develop public health and policy solutions that mitigate these ongoing severe public health issues.
Our objective was to examine SI in methamphetamine users to allow us to determine prevalence and trends by age, sex, race, and geographical region.
Using data collected between 2008 and 2019 from the National Inpatient Sample (NIS) database, we identified hospital admissions (HA) of patients ≥18 years of age with a primary or secondary diagnosis of SI who were also diagnosed as methamphetamine users. Those who used other substances with methamphetamine were excluded from the analysis.
To determine the trend and prevalence of hospital admissions due to SI and SI among methamphetamine users, we used trend weights to calculate the national estimates and performed design-based analysis to account for complex survey design and sampling weights on data collected between 2008 and 2019 in the US.
The prevalence ratio (PR) of hospitalizations with concurrent SI and methamphetamine use increased 16-fold from 2008 to 2019. The most significant increase occurred between 2015 and 2016; the PR doubled from 6.07 to 12.14. The PR of hospitalizations with concurrent SI and methamphetamine use was highest in patients aged 26-40 (49.08%) and 41-64 (28.49%). Patients aged 41-64 showed the most significant increase from 2008 to 2019 (15.8-fold). While non-Hispanic White patients comprised most of these hospitalizations (77.02%), non-Hispanic Black patients showed the highest proportional increase (39.1-fold). The Southern and Western regions in the US showed the highest PR for these hospitalizations (34.86% and 34.31%, respectively).
Our findings indicate that SI in methamphetamine users has been increasing for some time and is likely to grow. In addition, our results suggest that these patients are demographically different. Both conditions are associated with a lesser likelihood of seeking and receiving care. Therefore, when addressing increased SI or methamphetamine use, learning more about patients who share both conditions is necessary to ensure proper care.
Telomeres, repetitive nucleoprotein complexes that protect chromosomal termini and prevent them from activating inappropriate DNA damage responses (DDRs), shorten with cell division and thus with ...aging. Here, we characterized the human cellular response to targeted telomeric double-strand breaks (DSBs) in telomerase-positive and telomerase-independent alternative lengthening of telomere (ALT) cells, specifically in G1 phase. Telomeric DSBs in human G1 cells elicited early signatures of a DDR; however, localization of 53BP1, an important regulator of resection at broken ends, was not observed at telomeric break sites. Consistent with this finding and previously reported repression of classical non-homologous end-joining (c-NHEJ) at telomeres, evidence for c-NHEJ was also lacking. Likewise, no evidence of homologous recombination (HR)-dependent repair of telomeric DSBs in G1 was observed. Rather, and supportive of rapid truncation events, telomeric DSBs in G1 human cells facilitated formation of extensive tracks of resected 5' C-rich telomeric single-stranded (ss)DNA, a previously proposed marker of the recombination-dependent ALT pathway. Indeed, induction of telomeric DSBs in human ALT cells resulted in significant increases in 5' C-rich (ss)telomeric DNA in G1, which rather than RPA, was bound by the complementary telomeric RNA, TERRA, presumably to protect these exposed ends so that they persist into S/G2 for telomerase-mediated or HR-dependent elongation, while also circumventing conventional repair pathways. Results demonstrate the remarkable adaptability of telomeres, and thus they have important implications for persistent telomeric DNA damage in normal human G1/G0 cells (e.g., lymphocytes), as well as for therapeutically relevant targets to improve treatment of ALT-positive tumors.
Spontaneous telomere loss has been proposed as an important mechanism for initiating the chromosome instability commonly found
in cancer cells. We have previously shown that spontaneous telomere loss ...in a human cancer cell line initiates breakage/fusion/bridge
(B/F/B) cycles that continue for many cell generations, resulting in DNA amplification and translocations on the chromosome
that lost its telomere. We have now extended these studies to determine the effect of the loss of a single telomere on the
stability of other chromosomes. Our study showed that telomere acquisition during B/F/B cycles occurred mainly through translocations
involving either the nonreciprocal transfer or duplication of the arms of other chromosomes. Telomere acquisition also occurred
through small duplications involving the subtelomeric region of the other end of the same chromosome. Although all of these
mechanisms stabilized the chromosome that lost its telomere, they differed in their consequences for the stability of the
genome as a whole. Telomere acquisition involving nonreciprocal translocations resulted in the loss of a telomere on the donor
chromosome, which consequently underwent additional translocations, isochromosome formation, or complete loss. In contrast,
telomere acquisition involving duplications stabilized the genome, although the large duplications created substantial allelic
imbalances. Thus, the loss of a single telomere can generate a variety of chromosome alterations commonly associated with
human cancer, not only on a chromosome that loses its telomere but also on other chromosomes. Factors promoting telomere loss
are therefore likely to have an important role in generating the karyotype evolution associated with human cancer.
PDF
