When antibiotics encounter microplastics in aquatic environments: Interaction, combined toxicity, and risk assessments

Antibiotics and microplastics (MPs), known as emerging pollutants, are bound to coexist in aquatic environments due to their widespread distribution and prolonged persistence. To date, few systematic summaries are available for the interaction between MPs and antibiotics in aquatic ecosystems, and a comprehensive reanalysis of their combined toxicity is also needed. Based on the collected published data, we have analyzed the source and distribution of MPs and antibiotics in global aquatic environments, finding their coexistence occurs in a lot of study sites. Accordingly, the presence of MPs can directly alter the environmental behavior of antibiotics. The main influencing factors of interaction between antibiotics and MPs have been summarized in terms of the characteristics of MPs and antibiotics, as well as the environmental factors. Then, we have conducted a meta-analysis to evaluate the combined toxicity of antibiotics and MPs on aquatic organisms and the related toxicity indicators, suggesting a significant adverse effect on algae, and inapparent on fish and daphnia. Finally, the environmental risk assessments for antibiotics and MPs were discussed, but unfortunately the standardized methodology for the risk assessment of MPs is still challenging, let alone assessment for their combined toxicity. This review provides insights into the interactions and environment risks of antibiotics and MPs in the aquatic environment, and suggests perspectives for future research.

Low temperature acclimation of electroactive microorganisms may be an effective strategy to enhance the toxicity sensing performance of microbial fuel cell sensors

Microbial fuel cell (MFC) sensing is a promising method for real-time detection of water biotoxicity, however, the low sensing sensitivity limits its application. This study adopted low temperature acclimation as a strategy to enhance the toxicity sensing performance of MFC biosensor. Two types of MFC biosensors were started up at low (10 °C) or warm (25 °C) temperature, denoted as MFC-Ls and MFC-Ws respectively, using Pb2+ as the toxic substance. MFC-Ls exhibited superior sensing sensitivities towards Pb2+ compared with MFC-Ws at both low (10 °C) and warm (25 °C) operation temperatures. For example, the inhibition rate of voltage of MFC-Ls was 22.81 % with 1 mg/L Pb2+ shock at 10 °C, while that of MFC-Ws was only 5.9 %. The morphological observation showed the anode biofilm of MFC-Ls had appropriate amount of extracellular polymer substances, thinner thickness (28.95 μm for MFC-Ls and 41.58 μm for MFC-Ws) and higher proportion of living cells (90.65 % for MFC-Ls and 86.01 % for MFC-Ws) compared to that of MFC-Ws. Microbial analysis indicated the enrichment of psychrophilic electroactive microorganisms and cold-active enzymes as well as their sensitivity to Pb2+ shock was the foundation for the effective operation and good performance of MFC-Ls biosensors. In conclusion, low temperature acclimation of electroactive microorganisms enhanced not only the sensitivity but also the temperature adaptability of MFC biosensors.

Planktonic/benthic Bathyarchaeota as a "gatekeeper" enhance archaeal nonrandom co-existence and deterministic assembling in the Yangtze River

Archaea, the third proposed domain of life, mediate carbon and nutrient cycling in global natural habitats. Compared with bacteria, our knowledge about archaeal ecological modes in large freshwater environments subject to varying natural and human factors is limited. By metabarcoding analysis of 303 samples, we provided the first integrate biogeography about archaeal compositions, co-existence networks, and assembling processes within a 6000 km continuum of the Yangtze River. Our study revealed that, among the major phyla, water samples owned a higher proportion of Thaumarchaeota (62.8%), while sediments had higher proportions of Euryarchaeota (33.4%) and Bathyarchaeota (18.8%). A decline of polarization in phylum abundance profile was observed from plateau/mountain/hill to basin/plain areas, which was attributed to the increase of nutrients and metals. Planktonic and benthic Bathyarchaeota tended to co-occur with both major (e.g., methanogens or Thermoplasmata) and minor (e.g., Asgard or DPANN) taxa in the non-random networks, harboring the highest richness and abundances of keystone species and contributing the most positively to edge number, node degree, and nearest neighbor degree. Furthermore, we noted significantly positive contributions of Bathyarchaeota abundance and network complexity to the dominance of deterministic process in archaeal assembly (water: 65.3%; sediments: 92.6%), since higher carbon metabolic versatility of Bathyarchaeota would benefit archaeal symbiotic relations. Stronger deterministic assembling was identified at the lower-reach plain, and higher concentrations of ammonium and aluminum separately functioning as nutrition and agglomerator were the main environmental drivers. We lastly found that the Three Gorges Dam caused a simultaneous drop of benthic Bathyarchaeota abundance, network co-existence, and deterministic effects immediately downstream due to riverbed erosion as a local interference. These findings highlight that Bathyarchaeota are a "gatekeeper" to promote fluvial archaeal diversity, stability, and predictability under varying macroscopic and microscopic factors, expanding our knowledge about microbial ecology in freshwater biogeochemical cycling globally.

Effect of chlorine disinfectant influx on biological sewage treatment process under the COVID-19 pandemic: Performance, mechanisms and implications

Since the onset of the COVID-19 Pandemic, large amounts of chlorine-containing disinfectants have been used to interrupt the spread of SARS-CoV-2 and residual chlorine eventually entered the hospital or municipal sewage treatment facilities. However, little is known about the effect of chlorine influx on the biological sewage treatment process. Here we investigated the effect of chlorine on the microbiome and the mechanism of microbial chlorine resistance in the activated sludge of the aerobic treatment process, using metagenomic and metatranscriptomic sequencing. We found that chlorine could negatively impact the aerobic treatment performance regarding nitrogen/COD removal with a dose-dependent effect, and the dual effects of chlorine dose and interaction time differentiated the microbial community in activated sludge. The decline of nitrogen/COD removal was attributed to the compressed activity of functional microorganisms, such as the ammonia oxidation bacteria, under chlorinated conditions, and the damage cannot be recovered in a short term. In addition, some microorganisms could survive in chlorinated conditions by up-regulating the chlorine resistance genes (CRGs) expression (approximately 1.5 times) and stimulating new CRGs expression. In particular, species Acinetobacter johnsonii could resist high concentrations of chlorine through various mechanisms, especially the overexpression of efflux pump function encoded by qac genes play a key role. Based on these results, considering the persistence of the epidemic and extensive use of chlorine disinfectants, it cannot be ignored that large amounts of residual chlorine are entering the biological treatment facility, and strictly de-chlorination measures or microbial chlorine resistance regulations before entering should be implemented.

May microbial ecological baseline exist in continental groundwater?

BACKGROUND

Microbes constitute almost the entire biological community in subsurface groundwater and play an important role in ecological evolution and global biogeochemical cycles. Ecological baseline as a fundamental reference with less human interference has been investigated in surface ecosystems such as soils, rivers, and ocean, but the existence of groundwater microbial ecological baseline (GMEB) is still an open question so far.

RESULTS

Based on high-throughput sequencing information derived from national monitoring of 733 newly constructed wells, we find that bacterial communities in pristine groundwater exhibit a significant lateral diversity gradient and gradually approach the topsoil microbial latitudinal diversity gradient with decreasing burial depth of phreatic water. Among 74 phyla dominated by Proteobacteria in groundwater, Patescibacteria act as keystone taxa that harmonize microbes in shallower aquifers and accelerate decline in bacterial diversity with increasing well-depth. Decreasing habitat niche breadth with increasing well-depth suggests a general change in the relationship among key microbes from closer cooperation in shallow to stronger competition in deep groundwater. Unlike surface-water microbes, microbial communities in pristine groundwater are predominantly shaped by deterministic processes, potentially associated with nutrient sequestration under dark and anoxic environments in aquifers.

CONCLUSIONS

By unveiling the biogeographic patterns and mechanisms controlling the community assembly of microbes in pristine groundwater throughout China, we firstly confirm the existence of GMEB in shallower aquifers and propose Groundwater Microbial Community Index (GMCI) to evaluate anthropogenic impact, which highlights the importance of GMEB in groundwater water security and health diagnosis. Video Abstract.

In situ Nanopore sequencing reveals metabolic characteristics of the Qilian glacier meltwater microbiome

Nanopore metagenomic sequencing enables rapid annotating microbiological ecosystems, and the previous glacier-related sequencing applications (e.g., targeted ice sheets, ice lake, and cryoconite holes) inspire us to explore high-altitude glacier meltwater at Qilian Mountain, China (3000 to 4000 m above sea level, MASL). Our findings suggest that (1) despite only several hundred meters apart, the microbial communities and functionalities are quite different among vertical alpine distributions; (2) the high-altitude Qilian meltwater microbiome serve several main metabolic functions, including sulfur oxidation, selenite decomposing, photosynthesis, energy production, enzymic, and UV tolerant activities. Meanwhile, our Nanopore metagenomic results indicate that the microbial classifications and functionalities (e.g., chaperones, cold-shock, specific tRNA species, oxidative stress, and resistance to toxic compounds) of Qilian meltwater are highly consistent with the other glacial microbiome, emphasizing that only certain microbial species can survive in the cold environment and the molecular adaptions and lifestyles remain stable all over the world. Besides, we have shown Nanopore metagenomic sequencing can provide reliable prokaryotic classifications within or among studies, which therefore can encourage more applications in the field given faster turnaround time. However, we recommend accumulating at least 400 ng nucleic acids (after extraction) and maximizing Nanopore library preparation efficiency before on-site sequencing to obtain better resolutions.

Interaction of silver nanoparticles with marine/lake snow in early formation stage

Marine and lake snows play an important ecological role in aquatic systems, and recent researches have also revealed their interactions with various pollutants. In this paper, the interaction of silver nanoparticles (Ag-NPs), a typical nano-pollutant, with marine/lake snow in the early formation stage was investigated by roller table experiments. Results indicated Ag-NPs promoted the accumulation of larger marine snow flocs while inhibited the development of lake snow. The promotion effect of AgNPs might be attributed to their oxidative dissolution into low-toxic silver chloride complexes in seawater, and the subsequent incorporation into marine snow, which would enhance the rigidity and strength of larger flocs and favor the development of biomass. Conversely, Ag-NPs mainly existed in the form of colloidal nanoparticles in lake water and their strong antimicrobial effect suppressed the growths of biomass and lake snow. In addition, Ag-NPs could also affect the microbial community of marine/lake snow, including impact on microbial diversity, and elevation on abundances of extracellular polymeric substances (EPS) synthesis genes and silver resistance genes. This work has deepened our understanding of the fate and ecological effect of Ag-NPs via the interaction with marine/lake snow in aquatic environments.

Is it really safe to replace decabromodiphenyl ether (BDE209) with decabromodiphenyl ethane (DBDPE)?: A perspective from hepatotoxicity

In this paper, the hepatocytotoxicity and aryl hydrocarbon receptor (AHR) activity of decabromodiphenyl ethane (DBDPE), decabromodiphenyl ether (BDE209) and other 18 analogues were evaluated in vitro using human normal liver cell L02. These dioxin-like compounds showed differential hepatocytotoxicity (EC₅₀  = 0.38-17.87 mg/L) and AHR activity (EROD activity = 4.53-46.35 U/μg). In silico study indicated the distance of π-π bonds between the benzene ring of compounds and residue Phe234 of AHR played a key role in the binding of AHR, and the substituents on the benzene ring also influenced the activity. Combining molecular biology and bioomics, the comprehensive investigations on the hepatotoxic mechanisms have demonstrated the AHR signaling pathway was the key mediation mechanism for the hepatotoxicity of DBDPE/BDE209. The cytochrome P450s (CYP2 family) mediated formation of reactive oxygenated intermediates might be the dominant toxic mechanism, which could produce oxidative stress or cause genotoxicity. Although the experimental toxicity of DBDPE was smaller relative to BDE209, the health risk of DBDPE may be much greater than we expected, due to the high potential to form a variety of dioxin-like intermediates by microbial oxidation of ethyl group. Therefore, whether it is really safe to replace BDE209 with DBDPE is a debatable question, and more ecotoxicological and health data are needed to clarify this issue.

The distinct resistance mechanisms of cyanobacteria and green algae to sulfamethoxazole and its implications for environmental risk assessment

Cyanobacteria and green algae are the OECD recommended test organisms for environmental toxicity assessments of chemicals. Whether the differences in these two species' responses to the identical chemical affect the assessment outcomes is a question worth investigating. Firstly, we investigated the distinct resistance mechanisms of Synechococcus sp. (cyanobacteria) and R. subcapitata (green algae) to sulfamethoxazole (SMX). The antioxidant system analysis demonstrated that R. subcapitata mainly relies on enhancing the activity of first line defense antioxidants, including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), which is the most powerful and efficient response to get rid of ROS, whereas Synechococcus sp. depends upon increasing the activity of glutathione-S-transferase (GST) and GPx to resist oxidative stress. Besides, a total 7 transformation products (TPs) of SMX were identified in R. subcapitata culture medium. The analysis of conjectural transformation pathways and the predicted toxicity indicates that R. subcapitata could relieve SMX toxicity by degrading it to low eco-toxic TPs. Additionally, we summarized numerous exposure data and assessed the environmental risk of various antibiotics, revealing an inconsistent result for the same type of antibiotic by using cyanobacteria and green algae, which is most likely due to the different resistance mechanisms. In the future, modified indicators or comprehensive assessment methods should be considered to improve the rationality of environmental toxicity assessments.

Significant alterations of intestinal symbiotic microbiota induced by intraperitoneal vaccination mediate changes in intestinal metabolism of NEW Genetically Improved Farmed Tilapia (NEW GIFT, Oreochromis niloticus)

BACKGROUND

After millions of years of coevolution, symbiotic microbiota has become an integral part of the host and plays an important role in host immunity, metabolism, and health. Vaccination, as an effective means of preventing infectious diseases, has been playing a vital role in the prevention and control of human and animal diseases for decades. However, so far, minimal is known about the effect of vaccination on fish symbiotic microbiota, especially mucosal microbiota, and its correlation with intestinal metabolism remains unclear.

METHODS

Here we reported the effect of an inactivated bivalent Aeromonas hydrophila/Aeromonas veronii vaccine on the symbiotic microbiota and its correlation with the intestinal metabolism of farmed adult Nile tilapia (Oreochromis niloticus) by 16S rRNA gene high-throughput sequencing and gas chromatography-mass spectrometry metabolomics.

RESULTS

Results showed that vaccination significantly changed the structure, composition, and predictive function of intestinal mucosal microbiota but did not significantly affect the symbiotic microbiota of other sites including gill mucosae, stomach contents, and stomach mucosae. Moreover, vaccination significantly reduced the relative abundance values of potential opportunistic pathogens such as Aeromonas, Escherichia-Shigella, and Acinetobacter in intestinal mucosae. Combined with the enhancement of immune function after vaccination, inactivated bivalent Aeromonas vaccination had a protective effect against the intestinal pathogen infection of tilapia. In addition, the metabolite differential analysis showed that vaccination significantly increased the concentrations of carbohydrate-related metabolites such as lactic acid, succinic acid, and gluconic acid but significantly decreased the concentrations of multiple lipid-related metabolites in tilapia intestines. Vaccination affected the intestinal metabolism of tilapia, which was further verified by the predictive function of intestinal microbiota. Furthermore, the correlation analyses showed that most of the intestinal differential microorganisms were significantly correlated with intestinal differential metabolites after vaccination, confirming that the effect of vaccination on intestinal metabolism was closely related to the intestinal microbiota.

CONCLUSIONS

In conclusion, this paper revealed the microbial and metabolic responses induced by inactivated vaccination, suggesting that intestinal microbiota might mediate the effect of vaccination on the intestinal metabolism of tilapia. It expanded the novel understanding of vaccine protective mechanisms from microbial and metabolic perspectives, providing important implications for the potential influence of vaccination on human intestinal microbiota and metabolism. Video Abstract.

Nanopore-based long-read metagenomics uncover the resistome intrusion by antibiotic resistant bacteria from treated wastewater in receiving water body

Wastewater treatment plant (WWTP) effluent discharge could induce the resistome enrichment in the receiving water environments. However, because of the general lack of a robust antibiotic-resistant bacteria (ARB) identification method, the driving mechanism for resistome accumulation in receiving environment is unclear. Here, we took advantage of the enhanced ARBs recognition by nanopore long reads to distinguish the indigenous ARBs and the accumulation of WWTP-borne ARBs in the receiving water body of a domestic WWTP. A bioinformatic framework (named ARGpore2: https://github.com/sustc-xylab/ARGpore2) was constructed and evaluate to facilitate antibiotic resistance genes (ARGs) and ARBs identification in nanopore reads. ARGs identification by ARGpore2 showed comparable precision and recall to that of the commonly adopt BLASTP-based method, whereas the spectrum of ARBs doubled that of the assembled Illumina dataset. Totally, we identified 33 ARBs genera carrying 65 ARG subtypes in the receiving seawater, whose concentration was in general 10 times higher than clean seawater's. Notably we report a primary resistome intrusion caused by the revival of residual microbes survived from disinfection treatment. These WWTP-borne ARBs, including several animal/human enteric pathogens, contributed up to 85% of the receiving water resistome. Plasmids and class 1 integrons were reckoned as major vehicles facilitating the persistence and dissemination of ARGs. Moreover, our work demonstrated the importance of extensive carrier identification in determining the driving force of multifactor coupled resistome booming in complicated environmental conditions, thereby paving the way for establishing priority for effective ARGs mitigation strategies.

What are the ideal systolic and diastolic blood pressure which do not injure the intima of iliac and coronary arteries?

 

For patients with coronary artery disease, hypertension (HTN) is a major risk factor. How could uncontrolled HTN start atherosclerosis? In our prior research, laminar flow in coronary arteries prevented the formation of plaques while turbulent flow injured the intima and triggered atherosclerosis. In this present study our question was: Which blood pressure (BP) level is optimal in not producing turbulence and so not injuring the intima?

Methods

At first, a systolic BP<120mmHg and diastolic BP<75mmHg) were arbitrarily set as controlled (group A) while a BP of >160/105mmHg as uncontrolled (group B). All patients underwent a dynamic coronary angiogram recorded at 15 images/second or 0.06 seconds per image. The first image was of the index artery completely filled with contrast. In subsequent images the blood in white color moved in over a background of black contrast (Figure 1A). In 1B, 0.06 seconds later, the blood arrived at the mid segment (white arrow). In 1C, the flood moved forward, however there was darker contrast hanging at the mid segment, marking the location of collision from the retrograde against the antegrade flow (white arrow). The reason was that in uncontrolled BP the contraction of the left ventricle was stronger so in systole, the coronary blood could reverse its course, run on a retrograde direction, collide against the antegrade flow and create turbulence (1C).

At the end, before deploying a vascular closure device, an iliac angiogram was performed. In Figure 2, on a black background of contrast, the blood in white color moved forward with a pointed tip of laminar flow. 0.06 seconds later, the laminar tip was stopped abruptly with all the layers recoiling on each other like a falling stack of dominoes. In the next image. a large swirl of disorganized mixing of blood and contrast suggested the presence of turbulence caused by the collision.

The data to be collected were (1) the duration of the antegrade and retrograde flow, (2) duration of the collision (turbulence at the collision site)

Results

In the group A (BP <120/75 mmHg), 90% of 20 patients had no retrograde flow nor collision in the iliac and short collision in coronary arteries (<0.12 secs). In 30 patients of group B (BP >160/105 mmHg), the duration of retrograde flow and collision in the iliac artery were prolonged at >0.24 msecs. In the coronary arteries, the duration was prolonged at 0.18 msecs (all p<0.05 compared with group A). These locations of turbulence correlated with the location of plaques in our prior studies.

Conclusion

In patients with uncontrolled HTN, the retrograde flow was prolonged, and the turbulence was intense. In contrary, for patients with controlled BP, there was no retrograde flow and weaker collision in coronary arteries. The results suggest that a BP of <120/75 mmHg may not trigger the atherosclerotic process. New clinical trials with larger number of patients should be performed in search for the lowest ideal blood pressure.

Funding Acknowledgement

Type of funding sources: None.

Rare biosphere regulates the planktonic and sedimentary bacteria by disparate ecological processes in a large source water reservoir

The bacteria in the water column and surface sediments are inherently intertwined and inseparable in aquatic ecosystems, yet little is known about the integrated spatiotemporal dynamics and driving mechanisms of both planktonic and sedimentary bacterial communities in reservoirs. By investigating the planktonic and sedimentary bacteria during four seasons from 88 samples of 11 representative sites across the Danjiangkou reservoir, we depicted an integrated biogeographic pattern of bacterial communities in the water source of the world's largest water diversion project. Our study revealed both planktonic (mantel r = 0.502, P = 0.001) and sedimentary (mantel r = 0.131, P = 0.009) bacterial communities were significantly correlated with environmental heterogeneity, but a weak disparity along spatial heterogeneity, and the significant seasonal dynamics of planktonic (mantel r = 0.499, P = 0.001) rather than sedimentary bacteria. Particularly, rare biosphere played a main role in determining the community succession in the reservoir. It not only exhibited a more striking environmental separation than abundant taxa but also was an essential part in mediating spatiotemporal shifts of planktonic bacteria and maintaining the stability of bacterial community. These rare bacteria were respectively mediated by stochastic (62.68%) and selective (79.60%) processes in water and sediments despite abundant taxa being largely determined by stochastic processes (86.88-93.96%). Overall, our study not only fills a gap in understanding the bacterial community dynamics and underlying drivers in source water reservoirs, but also highlights the particular importance of rare bacteria in mediating biogeochemical cycles in world's large reservoir ecosystems.

Enhanced removal efficiency of sulfamethoxazole by acclimated microalgae: Tolerant mechanism, and transformation products and pathways

This study utilized sulfamethoxazole (SMX) acclimatization to enhance the tolerance and biodegradation capacity of Chlorella vulgaris. Compared to wild C. vulgaris, the growth inhibition and oxidative damage induced by SMX evidently decreased in acclimated C. vulgaris, and meanwhile photosynthetic and antioxidant activities were significantly promoted. The physiological analyses with the aid of principal component analysis revealed the increase of catalase and glutathione reductase activities was the critical tolerant mechanism of acclimated C. vulgaris. As the consequence, the acclimated C. vulgaris exhibited enhanced efficiency and (pseudo-first-order) kinetic rate for removal of SMX. The distribution analysis of residual SMX demonstrated the biodegradation was the major removal mechanism of SMX by C. vulgaris, while bioadsorption and bioaccumulation made pimping contributions. During the degradation process of SMX, nine transformation products (TPs) were identified. Based on the identified TPs, a possible transformation pathway was proposed.

Effect of Nano-Silver on Formation of Marine Snow and the Underlying Microbial Mechanism

Roller experiments were conducted to explore the effect of nano-silver on the formation of marine snow and the underlying microbial mechanism. With the increasing concentration of nano-Ag from 1 ng/L to 1 mg/L, the formation and aggregation of marine snow particles were solidly suppressed in a dose-dependent pattern. Moreover, the formed marine snows tended to be thinner fibrous particles with smaller size and increased edge smoothness and compactness in the presence of nano-Ag. The microbial analyses indicated that nano-Ag not only inhibited the development of biomass but also changed the species composition and functional profile of the microbial community. Nano-Ag obviously inhibited most of the abundant species, except for some myxobacteria, which is unfavorable for the microbial community stability. For the microbial functions, some major biological processes including the growth, metabolic, and cellular processes were also inhibited by the high dosage of nano-Ag. The strong microbial inhibition of nano-Ag would contribute to the suppression on the formation of marine snow. Specifically, the function genes of extracellular polymeric substance synthesis and secretion were significantly reduced by nano-Ag, which might be the key and straight microbial factor in suppressing the formation of marine snow.

Response of microbial nitrogen transformation processes to antibiotic stress in a drinking water reservoir

Effects of antibiotics on microbial nitrogen transformation processes in natural aquatic ecosystems are largely unknown. In this study, we utilized the ¹⁵N stable isotope tracers and metagenomic sequencing to identify how antibiotics drive nitrogen transformation processes in Danjiangkou Reservoir, which is the largest artificial drinking water reservoir in China. We retrieved 51 nitrogen functional genes, and found that the highest abundances of nitrate reduction and denitrification-related genes occurred in dissimilatory nitrogen transformation pathways. ¹⁵N-labelling analysis substantiated that denitrification was the main pathway for nitrogen removal, accounting for 57.1% of nitrogen loss. Nitrogen functional genes and antibiotic resistance genes co-occurred in Danjiangkou Reservoir, and they were mainly carried by the denitrifying bacteria such as Rhodoferax, Polaromonas, Limnohabitans, Pararheinheimera, Desulfobulbus, and Pseudopelobacter. Genome annotation revealed that antibiotic deactivation, Resistance-Nodulation-Division and facilitator superfamily efflux pumps were responsible for the multiple-resistance to antibiotics in these bacteria. Moreover, antibiotics showed non-significant effects on nitrogen transformation processes. It is speculated that denitrifying bacteria harboring ARGs played crucial roles in protecting nitrogen transformation from low-level antibiotics stress in the reservoir. Our results highlight that denitrifying bacteria are important hosts of ARGs, which provides a novel perspective for evaluating the effects of antibiotics on nitrogen cycle in natural aquatic ecosystems.

Influences of petroleum hydrocarbon pyrene on the formation, stability and antibacterial activity of natural Au nanoparticles

The effect of pyrene on the formation of naturally Au nanoparticles (AuNPs) in the presence of humic acid (HA) under UV irradiation is described. TEM, EDS, FTIR and XPS were carried out to prove the formation of AuNPs and display their morphologies and formation mechanism. There are little differences between size, morphology and function groups of surface coated materials of AuNPs formed with and without pyrene. With the presence of HA, pyrene showed an inhibiting effect on the reduction of Au ion via competition for O₂^•-, thereby decreasing the production of AuNPs. However, AuNPs formed by HA-pyrene showed higher stability than AuNPs formed by HA with the sedimentation rates of 4.13% and 13.68% respectively after 30-d standing. As for the antibacterial activities against Staphylococcus aureus and Escherichia coli, AuNPs formed by HA-pyrene were more toxic than AuNPs formed by HA. Meanwhile, changes of environmental factors such as temperature, pH and ionic strength exhibited similar influence trend on the formation of AuNPs in the presence and absence of pyrene. The results suggest that the typical petroleum hydrocarbon pyrene contained in spilled oil could influence the formation, fate and ecotoxicity of AuNPs.

Enhanced degradation of reactive brilliant red X-3B by photocatalysis integrated with micro-electrolysis

The microwave electrodeless lamp UV photocatalysis (MWUV) integrated with iron carbon micro-electrolysis (ME) was applied to degrade reactive brilliant red X-3B. In the present study, the removal rate of X-3B by MWUV/ME was 95%, which was significantly higher than 56% of MWUV and 62% of ME system. The experiment results demonstrated a synergistic effect in MWUV/ME system, wherein the ME system played an important role in color removal and the formation of ·OH in photocatalysis contributed most for the mineralization of X-3B and its intermediates. The removal efficiency of TOC was 32%, 7.5%, and 59.5% under MWUV, ME, and MWUV/ME processes at the end of the reaction, respectively. The Fe³⁺ existed in the system was an enhancer of producing ·OH via self-generation of ·OH by UV irradiation or improving the separation of electron-hole in photocatalysis by capturing the electrons. Therefore, the combined treatment of MWUV and ME system has the potential of synergistic effect compared to the separate process. Lowering the initial solution pH and increasing the iron filing dosage and dissolved oxygen were beneficial for the enhancement of degradation efficiency. The inorganic anions showed a diversity influencing the degradation of X-3B. NO₃^-, CO₃^2-, and SO₄^2- (at higher concentration) promoted the degradation reaction, while Cl^- had non-significant effect.

Metagenomic and viromic data mining reveals viral threats in biologically treated domestic wastewater

Activated sludge (AS), a common biological secondary treatment process in wastewater treatment plants (WWTPs), is known to remove a large spectrum of microorganisms. Yet little is known about its effect on the entire viral community. After compiling 3 Tbp of next-generation sequencing (NGS) metagenomic/viromic datasets consisted of 119 sub-datasets of influent, effluent, and AS samples from 27 WWTPs, viral removal efficacy is evaluated through data mining. The normalized abundance of viruses suggests effluents exhibit the highest viral prevalence (3.21 ± 3.26%, n = 13) followed by the AS (0.48 ± 0.25%, n = 57) and influents (0.23 ± 0.17%, n = 17). In contrast, plasmids, representing genetic element of bacteria, show higher average prevalence (0.73 ± 0.82%, n = 17) in influents than those of the AS (0.63 ± 0.26%, n = 57) and effluents (0.35 ± 0.42%, n = 13). Furthermore, the abundance-occupancy analysis identifies 142 core phage viruses and 17 non-phages core viruses, including several pathogenic viruses in the AS virome. The persistent occurrence of pathogenic viruses, coupled with non-favorable virus removal by the AS treatment, reveals the hidden virus threats in biologically treated domestic wastewater. The mechanisms for why viruses persist and the possibility that WWTPs are potential hotspots for viral survival deserve attention.

Active ammonia-oxidizing bacteria and archaea in wastewater treatment systems

Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are two microbial groups mediating nitrification, yet little is presently known about their abundances and community structures at the transcriptional level in wastewater treatment systems (WWTSs). This is a significant issue, as the numerical abundance of AOA or AOB at the gene level may not necessarily represent their functional role in ammonia oxidation. Using amoA genes as molecular markers, this study investigated the transcriptional abundance and community structure of active AOA and AOB in 14 WWTSs. Quantitative PCR results indicated that the transcriptional abundances of AOB amoA (averaged: 1.6 × 10⁸ copies g^-1 dry sludge) were higher than those of AOA (averaged: 3.4 × 10⁷ copies g^-1 dry sludge) in all WWTSs despite several higher abundances of AOA amoA at the gene level. Moreover, phylogenetic analysis demonstrated that Nitrosomonas europaea and unknown clusters accounted for 37.66% and 49.96% of the total AOB amoA transcripts, respectively, suggesting their dominant role in driving ammonia oxidation. Meanwhile, AOA amoA transcripts were only successfully retrieved from 3 samples, and the Nitrosospaera sister cluster dominated, accounting for 83.46%. Finally, the substrate utilization kinetics of different AOA and AOB species might play a fundamental role in shaping their niche differentiation, community composition, and functional activity. This study provides a basis for evaluating the relative contributions of ammonia-oxidizing microorganisms (AOMs) to nitrogen conversions in WWTSs.

A metagenomic-based method to study hospital air dust resistome

As a symbol of the defense mechanisms that bacteria have evolved over time, the genes that make bacteria resist antibiotics are overwhelmingly present in the environment. Currently, bacterial antibiotic resistance genes (ARGs) in the air are a serious concern. Previous studies have identified bacterial communities and summarized putative routes of transmissions for some dominant hospital-associated pathogens from hospital indoor samples. However, little is known about the possible indoor air ARG transportation. In this study, we mainly surveyed air-conditioner air dust samples under different airflow conditions and analyzed these samples using a metagenomic-based method. The results show air dust samples exhibited a complex resistome, and the average concentration is 0.00042 copies/16S rRNA gene, which is comparable to some other environments. The hospital air-conditioners can form resistome over time and accumulate pathogens. In addition, our results indicate that the Outpatient hall is one of the main ARG transmission sources, which can distribute ARGs to other departments (explains >80% resistome). We believe that the management should focus on ARG carrier genera such as Staphylococcus, Micrococcus, Streptococcus, and Enterococcus in this hospital and our novel evidence-based network strategy proves that plasmid-mediated ARG transfer can occur frequently. Overall, these results provide insights into the characteristics of air dust resistome and possible route for how ARGs are spread in air.

Spatiotemporal distribution, risk assessment and source appointment of metal(loid)s in water and sediments of Danjiangkou Reservoir, China

Danjiangkou Reservoir is the biggest artificial reservoir in China. But spatiotemporal distribution and risks of metal(loid)s in it were still unclear after the operation of Middle Route of South-to-North Water Diversion Project. In this study, distribution pattern of fifteen metal(loid)s in the Danjiangkou Reservoir was investigated. It was shown that metal(loid)s concentrations in the water were much lower than the drinking water quality standards in China, while Sb, Co, Cd and Cr were identified as the major pollutants in the sediments. Environment-metal(loid)s correlation analysis revealed total organic carbon, sulfate, temperature, dissolved oxygen and total phosphorus markedly controlled metal(loid)s distribution in the water, while organic carbon, total phosphorus and ammonia nitrogen shaped their distribution in the sediments. Results of risk assessment further revealed that the sediments of Danjiangkou Reservoir were minor to moderate polluted, and Sb, Cd exhibited the highest potential ecological risk. Additionally, source identification showed agricultural activities (25.3%), industrial and mining activities (17.5%) and natural processes (57.2%) were the dominant sources of metal(loid)s burden in the sediments. Overall, the results are of significance to understanding the ecological risk and pollution sources in the Danjiangkou Reservoir, which is essential for the effective management of metal(loid)s pollution.

Pre-accumulation and in-situ destruction of diclofenac by a photo-regenerable activated carbon fiber supported titanate nanotubes composite material: Intermediates, DFT calculation, and ecotoxicity

Pharmaceuticals and personal care products (PPCPs) have been widely detected in ecosystems. However, effective water purification technologies for PPCPs degradation are lacking. In this work, an active activated carbon fiber supported titanate nanotubes (TNTs@ACF) composite was synthesized via one-step hydrothermal process, which was applied for adsorption and photocatalytic degradation of PPCPs under simulated solar light. Characterizations indicated that the successful grafting of TNTs onto ACF was achieved and surface modification occurred. Diclofenac (DCF, a model PPCPs) was rapidly adsorbed onto TNTs@ACF, and subsequently photodegraded (98.8 %) under solar light within 2 h. TNTs@ACF also performed well over a wide range of pH, and was resistant to humic acid. The good adsorption and photocatalytic activity of TNTs@ACF was attributed to the well-defined hybrid structure, enabling corporative adsorption of DCF by TNTs and ACF, and extending the light absorbance to visible region. Furthermore, the description of degradation pathway and evaluation of ecotoxicity for DCF and its intermediates/byproduct were proposed based on experimental analysis, density functional theory (DFT) calculation and quantitative structure-activity relationship (QSAR) analysis, respectively, indicating the photocatalytic degradation of DCF can offer the step-by-step de-toxicity. Our study is expected to offer new strategy as "pre-accumulation and in-situ destruction" for environmental application.

Radical attack and mineralization mechanisms on electrochemical oxidation of p-substituted phenols at boron-doped diamond anodes

Degradation of phenols with different substituent groups (including -OCH₃, -CHO, -NHCOCH₃, -NO₂, and -Cl) at boron-doped diamond (BDD) anodes has been studied previously based on the removal efficiency and •OH detection. Innovatively, formations of CO₂ gas and various inorganic ions were examined to probe the mineralization process combined with quantitative structure-activity relationship (QSAR) analysis. As results, all phenols were efficiently degraded within 8 h with high COD removal efficiency. Three primary intermediates (hydroquinone, 1,4-benzoquinone and catechol) were identified during electrochemical oxidation and degradation pathway was proposed. More importantly, CO₂ transformation efficiency ranked as: no N or Cl contained phenols (p-CHO, p-OCH₃ and Ph) > N-contained phenols (p-NHCOCH₃ and p-NO₂) > Cl-contained phenols (p-Cl and o,p-Cl). Carbon mass balance study suggested formation of inorganic carbon (H₂CO₃, CO₃^2- and HCO₃^-) and CO₂ after organic carbon elimination. Inorganic nitrogen species (NH₄⁺, NO₃^- and NO₂^-) and chlorine species (Cl^-, ClO₃^- and ClO₄^-) were also formed after N- and Cl-contained phenols mineralization, while no volatile nitrogen species were detected. The phenols with electron-withdrawing substituents were easier to be oxidized than those with electron-donating substituents. QSAR analysis indicated that the reaction rate constant (k₁) for phenols degradation was highly related to Hammett constant (∑σ_o,m,p) and energy gap (E_LUMO - E_HOMO) of the compound (R² = 0.908), which were key parameters on evaluating the effect of structural moieties on electronic character and the chemical stability upon radical attack for a specific compound. This study presents clear evidence on mineralization mechanisms of phenols degradation at BDD anodes.

Effect of modified basic oxygen furnace slag on the controlled release of nitrate nitrogen and the functional microbial community in soil

The specific surface area and active adsorption sites of basic oxygen furnace (BOF) slag increase after BOF modification. The addition of modified BOF slag to the soil may enable the control of nitrate nitrogen (NO₃-N) leaching and also affect the functional microflora in the soil. In this study, soil column leaching experiments were conducted to explore the effects of adding modified slag to the soil on the controlled release of NO₃-N and the main functional microbial communities involved in nitrification and denitrification processes. The experimental design included seven column groups: a soil control group (CT); soil groups with 2.5%, 5%, and 10% raw slag (S1, S2, S3); and soil groups with 2.5%, 5%, and 10% modified slag (MS1, MS2, MS3) that were subjected to three cycles of leaching, each of which were comprised of five leaching treatments. After the three cycles of leaching, significantly less NO₃-N had leached from the modified slag group compared to the CT and the raw slag groups (P < 0.05). Although both slag treatments increased soil pH and decreased the oxidation reduction potential of the soil leaching solution, the addition of modified slag had less effect on soil pH than the addition of raw slag. During column leaching, the group with modified slag had a higher gene abundance of functional microflora compared with the group with raw slag. Similarly, the modified slag group had a higher diversity and richness of denitrifying bacteria, ammonia-oxidizing archaea, and ammonia-oxidizing bacteria than the raw slag group. In conclusion, the addition of modified slag to soil effectively decreased the NO₃-N leaching and had relatively little effect on the functional microbial community in the soil.

Effect of basic oxygen furnace slag on succession of the bacterial community and immobilization of various metal ions in acidic contaminated mine soil

As an immobilizing agent for metal ions, basic oxygen furnace slag may affect bacterial community succession, thus further promote metal ion immobilization in acidic contaminated soil. In this work, pot experiments were conducted to study the effects of adding 10 g/kg (S10) and 15 g/kg (S15) slag on soil properties, plant growth, bacterial community succession and various metal ion immobilization in acidic mine soils contaminated by Pb, Zn, Cu, Cr and Cd. The results showed that after 93 days of potting, the soil pH, electrical conductivity, total nitrogen and organic carbon content increased significantly (P < 0.05), and the dry weight of Poa pratensis L. increased significantly (P < 0.05) in S10 and S15 compared with in original soil group. With slag addition and plant growth, the diversity and richness indices of bacterial communities greatly improved, and at the genus level, the abundance of metal-tolerant bacteria and bacteria beneficial to plant growth increased, while the abundance of acidophiles decreased. After adding slag to the soil, the various metals were immobilized because slag could not only immobilize metal ions through ion exchange and coprecipitation, but also benefit plant growth and bacterial community succession which further promote the immobilization of metal ions.

RUNX1-activated upregulation of lncRNA RNCR3 promotes cell proliferation, invasion, and suppresses apoptosis in colorectal cancer via miR-1301-3p/AKT1 axis in vitro and in vivo

PURPOSE

Long non-coding RNAs (lncRNAs) have participated in progression of colorectal cancer. This study aims to study the role of RUNX1/RNCR3/miR-1301-3p/AKT1 axis in colorectal cancer.

METHODS

The cancer tissues were from patients with colorectal cancer. The qRT-PCR was used to determine expression of lncRNA RNCR3, miR-1301-3p, and AKT1. Both dual-luciferase reporter assay and ChIP assay were conducted to investigate the binding sites of RUNX1 on RNCR3 promoter. Western blot was performed to analyze expression of AKT1 protein. Both dual-luciferase reporter assay and RIP assay were performed to detect the interacting sites between RNCR3 and miR-1301-3p. The CCK-8 assay, soft agar assay, transwell assay, and annexin-V-FITC/PI staining were applied to analyze the cell growth, invasion, and apoptosis, respectively.

RESULTS

The data demonstrated that RNCR3 was elevated in colorectal cancer, and it was negatively correlated with expression of miR-1301-3p which was decreased in cancers. Then, RNCR3 could interact with and suppress miR-1301-3p expression in HCT116 and SW480. Knockdown of RNCR3 or miR-1301-3p overexpression significantly inhibited cell growth, invasion, and increased apoptosis through suppressing expression of Cyclin A1, PCNA, N-cadherin, Bcl-2, and promoting expression of E-cadherin, Bax in vitro and in vivo. RUNX1 was directly bound to RNCR3 promoter to activate RNCR3 expression. Furthermore, overexpression of RNCR3 blocked tumor inhibitory effects of miR-1301-3p on proliferation, colony formation, invasion, and apoptosis in vitro and in vivo. Additionally, RNCR3 and miR-1301-3p synergistically modulated AKT1 expression.

CONCLUSION

RUNX1-activated upregulation of RNCR3 promoted colorectal cancer progression by sponging miR-1301-3p to elevate AKT1 levels in vitro and in vivo.

Efficient adsorption of europium (III) and uranium (VI) by titanate nanorings: Insights into radioactive metal species

Radioactive wastewater containing high concentration of radionuclides poses severe threats to ecosystem and human health, so efficient removal of these toxic heavy metals is urgently needed. Titanate nanomaterials have been demonstrated good adsorbents for heavy metals due to ion exchange property. In this study, titanate nanorings (TNRs) were synthesized using the facile hydrothermal-cooling method. The TNRs were composed of sodium trititanate, with a chemical formula of Na_0.66H_1.34Ti₃O₇•0.27H₂O and a Na content of 2.38 mmol/g. The TNRs demonstrated sufficient adsorption performance to radionuclides europium (Eu) and uranium (U) ions. Specifically, even at a high initial concentration of 50 mg/L, 86.5% and 92.6% of the two metal ions can be rapidly adsorbed by the TNRs within 5 min, and equilibrium was reached within 60 min at pH 5. The maximum adsorption capacity (Q _max) obtained by the Langmuir isotherm model was 115.3 mg/g for Eu(III) and 282.5 mg/g for uranium U(VI) at pH 5, respectively. The adsorption capacities of the two metals under various water chemical conditions were highly related to their species. Ion exchange between metal cations and Na⁺ in the TNR interlayers was the dominant adsorption mechanism, and adsorption of U(VI) was more complicated because of the co-existence of various uranyl (UO₂ ²⁺) and uranyl-hydroxyl species. The spent TNRs were effectively regenerated through an acid-base or ethylenediamine tetraacetic acid (EDTA) treatment and reused. Considering the large adsorption capacity and quick kinetic, TNRs are promising materials to remove radionuclides in environmental purification applications, especially emergent treatment of leaked radionuclides.

Metagenomic insights into the profile of antibiotic resistomes in a large drinking water reservoir

Reservoirs play a vital role in the control and management of surface water resources. However, the long water residence time in the reservoir potentially increases the storage and accumulation of antibiotic resistant genes (ARGs). The full profiles and potential health risks of antibiotic resistomes in reservoirs are largely unknown. In this study, we investigated the antibiotic resistomes of water and sediment during different seasons in the Danjiangkou Reservoir, which is one of the largest reservoirs in China, using a metagenomic sequencing approach. A total of 436 ARG subtypes belonging to 20 ARG types were detected from 24 water and 18 sediment samples, with an average abundance of 0.138 copies/cell. The overall ARG abundance in the sediment was higher than that in the water, and bacitracin and vancomycin resistance genes were the predominant ARG types in the water and sediment, respectively. The overall ARG abundance in the dry season was higher than that in the wet season, and a significant difference in ARG subtype compositions was observed in water, but not in the sediment, between the different seasons. The potential horizontal gene transfer frequency in the water was higher than that in the sediment, and the ARGs in water mainly came from the sediment upstream of the reservoir. The metagenomic assembly identified 14 contigs as ARG-carrying pathogens including Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, and 3 of 14 carried virulence factors. Overall, the potential public health risks posed by resistomes in the water of the Danjiangkou Reservoir were higher in the dry season than in the wet season. Based on these results, strategies including sediment control and pathogen monitoring are suggested for water safety management in drinking water reservoirs.

Abundance and community composition of comammox bacteria in different ecosystems by a universal primer set

Complete ammonia oxidizing bacteria (CAOB) have been recognized as a new member of ammonia-oxidizing microorganisms (AOMs) due to its single-step nitrification capability. However, the abundance and diversity of CAOB in environmental ecosystems were still far from known owing to the lack of specific molecular marker. Herein, a universal primer set specifically targeting both clades of CAOB amoA gene with high specificity and coverage was successfully designed. Intriguingly, real-time quantitative PCR tests revealed that CAOB were ubiquitous and unexpectedly abundant in agricultural soils, river sediments, intertidal zones, drinking water and wastewater treatment systems. Phylogenetic analysis indicated that clade A existed in all the five types of ecosystems, while clade B were only detected in soil and sediment samples. Four sub-clusters were further classified within clade A, in which N. nitrosa cluster dominated CAOB amoA in activated sludge samples while the new recognized soil cluster was the primary constitute in soils. Moreover, the niche specialization between different CAOB species and the environmental conditions were supposed to be the primary driven force to shape the diversity and community of CAOB. This study provided a strong evidence in support of the ubiquities and high abundances of CAOB in various environmental ecosystems and highlighted the significance of including CAOB as the new member of AOMs to re-evaluate the biogeochemical nitrogen cycle.

Role of sludge retention time in mitigation of nitrous oxide emission from a pilot-scale oxidation ditch

Nitrous oxide (N₂O) emission from wastewater treatment plants (WWTPs) has become a focus of attention due to its significant greenhouse effect. In this study, the role of sludge retention time (SRT) in mitigation of N₂O emission from a pilot-scale oxidation ditch was systematically investigated. The activated sludge system that operated at SRT of 25 days demonstrated significantly lower N₂O emission factor, higher resistance to ammonia overload and aeration failure shock than those obtained at SRT of 15 days no matter which hydraulic retention time (HRT) was adopted. Batch experiments revealed that nitrifier denitrification (ND) was the primary mechanism of N₂O generation. However, more microbes affiliated with Nitrospira genera were harbored in the system at SRT 25 d, which could effectively avoid nitrite accumulation, a key factor promoting N₂O generation by ND. PICRUSt results further suggested the system at SRT 25 d possessed higher genetic potential for N₂O reduction reflected by the more abundant nitrous-oxide reductase.

The immune profile of small HER2-positive breast cancers: a secondary analysis from the APT trial

BACKGROUND

Previous data suggest that the immune microenvironment plays a critical role in human epidermal growth factor receptor 2 (HER2) -positive breast cancer; however, there is little known about the immune profiles of small HER2-positive tumors. In this study, we aimed to characterize the immune microenvironment of small HER2-positive breast cancers included in the Adjuvant paclitaxel and trastuzumab for node-negative, HER2-positive breast cancer (APT) trial and to correlate the immune markers with pathological and molecular tumor characteristics.

PATIENTS AND METHODS

The APT trial was a multicenter, single-arm, phase II study of paclitaxel and trastuzumab in patients with node-negative HER2-positive breast cancer. The study included 406 patients with HER2-positive, node-negative breast cancer, measuring up to 3 cm. Exploratory analysis of tumor infiltrating lymphocytes (TIL), programmed death-ligand 1 (PD-L1) expression (by immunohistochemistry), and immune gene signatures using data generated by nCounter PanCancer Pathways Panel (NanoString Technologies, Seattle, WA), and their association with pathological and molecular characteristics was carried out.

RESULTS

Of the 406 patients, 328 (81%) had at least one immune assay carried out: 284 cases were evaluated for TIL, 266 for PD-L1, and 213 for immune gene signatures. High TIL (≥60%) were seen with greater frequency in hormone-receptor (HR) negative, histological grades 2 and 3, as well in HER2-enriched and basal-like tumors. Lower stromal PD-L1 (≤1%) expression was seen with greater frequency in HR-positive, histological grade 1, and in luminal tumors. Both TIL and stromal PD-L1 were positively correlated with 10 immune cell signatures, including Th1 and B cell signatures. Luminal B tumors were negatively correlated with those signatures. Significant correlation was seen among these immune markers; however, the magnitude of correlation did not indicate a monotonic relationship between them.

CONCLUSION

Immune profiles of small HER2-positive breast cancers differ according to HR status, histological grade, and molecular subtype. Further work is needed to explore the implication of these findings on disease outcome.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT00542451.

Prospective evaluation of the cardiac safety of HER2-targeted therapies in patients with HER2-positive breast cancer and compromised heart function: the SAFE-HEaRt study

Purpose

HER2-targeted therapies have substantially improved the outcome of patients with breast cancer, however, they can be associated with cardiac toxicity. Guidelines recommend holding HER2-targeted therapies until resolution of cardiac dysfunction. SAFE-HEaRt is the first trial that prospectively tests whether these therapies can be safely administered without interruptions in patients with cardiac dysfunction.

Methods

Patients with stage I–IV HER2-positive breast cancer candidates for trastuzumab, pertuzumab or ado-trastuzumab emtansine (TDM-1), with left ventricular ejection fraction (LVEF) 40–49% and no symptoms of heart failure (HF) were enrolled. All patients underwent cardiology visits, serial echocardiograms and received beta blockers and ACE inhibitors unless contraindicated. The primary endpoint was completion of the planned HER2-targeted therapies without developing either a cardiac event (CE) defined as HF, myocardial infarction, arrhythmia or cardiac death or significant asymptomatic worsening of LVEF. The study was considered successful if planned oncology therapy completion rate was at least 30%.

Results

Of 31 enrolled patients, 30 were evaluable. Fifteen patients were treated with trastuzumab, 14 with trastuzumab and pertuzumab, and 2 with TDM-1. Mean LVEF was 45% at baseline and 46% at the end of treatment. Twenty-seven patients (90%) completed the planned HER2-targeted therapies. Two patients experienced a CE and 1 had an asymptomatic worsening of LVEF to ≤ 35%.

Conclusion

This study provides safety data of HER2-targeted therapies in patients with breast cancer and reduced LVEF while receiving cardioprotective medications and close cardiac monitoring. Our results demonstrate the importance of collaboration between cardiology and oncology providers to allow for delivery of optimal oncologic care to this unique population.

Electronic supplementary material

The online version of this article (10.1007/s10549-019-05191-2) contains supplementary material, which is available to authorized users.

Antibiotics in water and sediments of Danjiangkou Reservoir, China: Spatiotemporal distribution and indicator screening

Danjiangkou Reservoir is the largest artificial freshwater lake in China. The occurrence and spatiotemporal distribution of 77 antibiotics in water and sediment samples from Danjiangkou Reservoir were investigated. Approximately 90% of the detectable concentrations of the 61 and 54 antibiotics found in water and sediment samples were lower than 5.0 ng/L and 1.0 ng/g, respectively. Sulfamethoxazole was the most abundant antibiotic found in water (1.65-149 ng/L, median 6.25 ng/L). In sediment samples, macrolides were frequently detected (42.7-54.5%) at concentrations of ND-4.34 ng/g. Greater diversity and higher levels of antibiotics were generally found in both water and sediment samples in spring than in the other seasons. Composition profiles of antibiotics differed between the two tributary river basins of Danjiangkou Reservoir, indicating different sources of contamination and the influence of water and sediment properties. Four criteria, namely widespread occurrence, correlation with the total antibiotic concentration, and risk to aquatic organisms or to human health, were suggested to select specific indicators for monitoring and pollution control of antibiotics. Five antibiotics were selected as appropriate indicators for Danjiangkou Reservoir, namely sulfamethoxazole, trimethoprim, clarithromycin, roxithromycin, and anhydrochlortetracycline. This study adds to the understanding of the occurrence of antibiotics in water reservoirs and can assist authorities in regulating antibiotic contamination and designing effective strategies for risk minimization.

Abstract P2-09-07: Preoperative pembrolizumab (Pembro) with radiation therapy (RT) in patients with operable triple-negative breast cancer (TNBC)

Background: Radiation therapy (RT) induces immune-mediated cell death and could generate a rich supply of tumor antigens if administered in the pre-operative, curative-intent setting. The addition of PD-1 mediated checkpoint blockade to pre-operative RT could thus, generate robust anti-tumor immune responses, induce long-term tumor-specific memory, and ultimately, improve cure rates. This study aims to establish the safety of pre-operative pembrolizumab (pembro)-mediated immune modulation with a RT “boost” equivalent in patients with operable triple negative breast cancer (TNBC) for whom lumpectomy and adjuvant RT are planned (NCT03366844). Serial research biopsies permit interrogation of conventional biomarkers including tumor infiltrating lymphocytes (TILs) and novel immune correlates as potential predictors of response to pembro alone versus pembro with RT.

Methods: Ten women with operable, primary TNBC &gt;2cm for whom breast-conserving therapy is planned are being enrolled in this single-institution pilot study. Study treatment consists of 1 cycle of pre-operative pembro (200 mg IV) alone, followed 3 weeks later by a RT boost (24 Gy/3 fractions) to the primary breast tumor concurrently with pembro (+/- 5 days). Curative-intent, standard-of-care, neoadjuvant chemotherapy (NAC) or breast-conserving surgery is then undertaken within 8 weeks of study enrollment (i.e. within 5 weeks of pembro #2). Adjuvant RT is administered per standard-of-care after surgery, but without a boost dose. Research blood and fresh tumor biopsies are obtained at baseline and after cycles 1 and 2 of pembro. Co-primary endpoints are: 1) safety/tolerability, as defined by the number of patients who do not necessitate a delay in standard-of-care chemotherapy or surgery and 2) change in TIL score. Secondary endpoints include safety/toxicity up to 19 weeks after study enrollment, pCR rates and disease-free survival. Correlative analysis will include single-cell RNA sequencing of the tumor immune infiltrate and multispectral immunohistochemistry

Results: Seven patients enrolled between 12/19/17 and 7/1/18. As of 7/1/18, 5 patients have completed the experimental pembro/RT phase of the trial and are currently completing standard-of-care NAC; 1 patient is currently being treated in the experimental pembro/RT phase; and 1 patient with a cT2N0 tumor at baseline achieved a pathologic complete response (pCR, ypT0/Tis ypN0) after completing the experimental pembro/RT phase followed by anthracycline- and taxane-based NAC. No grade 3 or 4 toxicities have been observed during pembro/RT in the 6 patients completing the experimental phase to date. Three additional patients will be enrolled

Conclusions: This is the first trial of curative-intent, pre-operative checkpoint blockade with RT in breast cancer and the strategy appears to be well tolerated to date. At the time of presentation, safety, change in TIL score, and pCR rates for all patients completing the experimental and NAC phases of the study will be reported.

Citation Format: McArthur HL, Basho R, Shiao SL, Park D, Mita M, Chung A, Arnold B, Martin C, Dang C, Karlan S, Knott S, Giuliano A, Ho A. Preoperative pembrolizumab (Pembro) with radiation therapy (RT) in patients with operable triple-negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-09-07.

Abstract P3-08-04: Transient state change, but not permanent subtype change, after HER2-targeted therapy for HER2-positive breast cancer

Background: In CALGB 40601 (Alliance, NCT00770809), a neoadjuvant phase III trial of paclitaxel and trastuzumab with or without lapatinib for 12 weeks for patients with HER2-positive breast cancer, 33% of pretreatment tumors were Luminal A subtype, however, 69% of post-treatment samples with residual disease were Luminal A subtype. In addition, 71% of Luminal B (12/17) and 67% of HER2-Enriched (6/9) tumors changed into Luminal A, while 80% of Luminal A (20/24) remained Luminal A (Carey et al. J Clin Oncol. 2016). It is not known whether this shift to Luminal A was transient or permanent.

Methods: We selected matched pairs of pre- and post-treatment 40601 samples with tumor purity &gt;10% based upon DNA analyses to ensure all samples contained tumor. PAM50 intrinsic subtyping was applied to the 40601 samples gene expression data using a two-step normalization process based on The Genome Cancer Atlas, and PAM50 training set. In addition, a HER2-enriched expression subtype patient-derived xenograft (PDX) tumor called WHIM35, was studied and was either untreated (n=10), or treated with lapatinib at 220 mg/kg for 1 week (wk) (n=5), for 2 wks (n=8), or for 3 wks (n=4). We also treated WHIM35 tumors with lapatinib for 2 wks (on) and then removed laptinib for 1 wk (off) (n=6), or for 2 wks on and 2-4 wk off (n=6), and finally for 3 wks on, and 1 wk off (n=3). PAM50 intrinsic subtyping was applied to the PDX gene expression data and subtype assessed as well as a genomic-based proliferation score. ANOVA p-values were calculated by comparing median values across all gene signature or correlation scores.

Results: We found 10 pairs of 40601 samples that kept their tumor purity values, however, their subtype changed to Luminal A after treatment (i.e., in the residual disease), and in these cases no minor tumor subclone became a dominant clone in the post treatment sample. Pretreatment subtypes were 6 Luminal B, 3 Luminal A, and 1 HER2-enriched. The tumor purity values did not change after the treatments, but correlation to Luminal A was significantly higher (p=0.01), while correlation to HER2-enriched (p=0.004) and proliferation signature scores (p=0.003) were significantly lower in the post-treatment samples. Among the WHIM35 PDX tumors, one sample changed its subtype from HER2-enriched to Luminal A after the lapatinib treatment and the rest remained HER2-enriched, suggesting environmental differences between patient samples and the PDX model. However, correlation to Luminal A was significantly higher in all lapatinib treated WHIM35 samples (p=8.3e-12), and notably went back to the initial low levels just one week after removing lapatinib. Likewise, correlation to HER2-enriched (p=1.2e-10) and proliferation signature scores (p=6.2e-12) also got lower while treated with lapatinib, but went back to the initial levels after cessation of treatment.

Conclusions: Our findings suggest that the apparent subtype change during HER2-targeting therapy is not permanent, but is more likely a transient state change from a HER2-enriched subtype into a more Luminal A-like state. When we plan additional treatment strategies using residual disease phenotypes, it may not be clear what is the true subtype of the sample due to this inherent plasticity.

Citation Format: Tanioka M, Parker JS, Henry LN, Tolaney S, Dang C, Krop IE, Harris L, Polley M, Berry DA, Winer EP, Carey LA, Perou CM. Transient state change, but not permanent subtype change, after HER2-targeted therapy for HER2-positive breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-08-04.

Abstract P6-18-30: Phase Ib/II study of capecitabine 7/7 schedule with neratinib in patients with HER2-positive metastatic breast cancer (MBC)

Background: Neratinib (N) is a potent irreversible inhibitor of HER1, HER2, and HER4 and has been shown to have antitumor activity in patients (pts) with human epidermal growth factor receptor 2 (HER2) - positive breast cancer. A previous study of combination of neratinib with capecitabine (X) was associated with &gt; G 3 diarrhea in &gt; 20% of patients. Currently, the NALA study is evaluating this combination of N with X at standard schedule against control. X at 7 day on and 7 day off schedule (7/7) has been shown to be well-tolerated with less ≥G3 toxicities. We are conducting a phase Ib/II study of N with X (7/7) in pts with pretreated HER2+ MBC (NCT03377387). Methods: Eligible pts had HER2+ MBC, normal left ventricular ejection fraction (LVEF ≥ 50%); pts can have any and up to 4 prior chemotherapy-based treatments in phase Ib and II portions, respectively. Primary endpoints are to define maximum tolerated dose and efficacy in phase I and phase II portions, respectively. Secondary endpoints include safety and tolerability; exploratory endpoint is to quantify cell-free DNA to correlate with response for phase II portion. There were 4 cohorts for phase Ib with dose level 1 with starting dose of X at 1500 mg BID at 7/7 schedule with N at 240 mg daily. Results: As of July 1, 2018 8 pts have been enrolled in 2 cohorts. The median age is 63y (range: 57-79), and median ECOG is 0 (range: 0-1). 4 patients were treated at dose level 1 and 2 of 4 patients experienced dose-limiting toxicity with G3 diarrhea during cycle 1. Other significant toxicities included G3 hand foot syndrome (n=1), G3 fatigue (n=1) and G3 nausea (n=1). Three pts have now been treated at dose level -1 (X at 1000 mg twice daily 7/7 and N at 240 mg daily) and no ≥ G3 toxicities has been noted. Once MTD is reached, the phase II portion will occur to assess the efficacy and to further establish the safety and tolerability of capecitabine and neratinib at the MTD. Conclusions: The phase Ib/II study combining neratinib and capecitabine 7/7 is ongoing and updated result will be presented.

Citation Format: Wang R, Singh J, Sterlin V, Goldstein M, Lake D, Wong S, Baselga J, Norton L, Dang C. Phase Ib/II study of capecitabine 7/7 schedule with neratinib in patients with HER2-positive metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-30.

Newly designed primer pair revealed dominant and diverse comammox amoA gene in full-scale wastewater treatment plants

The discovery of complete ammonia oxidizing bacteria (CAOB) capable of performing the two-step nitrification process on their own has fundamentally upended our traditional perception. However, their environmental distribution and ecological significance in driving ammonia oxidation are still urgently awaited to be assessed. In this study, the diversity and abundance of CAOB amoA gene in wastewater treatment plants (WWTPs) were presented taking advantage of a newly designed primer pair specifically targeting CAOB amoA gene. Phylogenetic results demonstrated the novel amoA gene formed a clearly distinct cluster from the canonical amoA and pmoA genes. Among the five well-supported sub-clusters, Nitrospira nitrosa cluster accounted for 94.34% of all the currently retrieved sequences from WWTPs. More importantly, qPCR results demonstrated a remarkably high abundance of CAOB amoA gene, which were up to 182.7-fold more abundant than AOB amoA gene. This study provided new dimension and fundamental basis for future researches towards biogeochemical nitrogen cycle.