Salinity decline promotes growth and harmful blooms of a toxic alga by diverting carbon flow.

Global climate change intensifies the water cycle and makes freshest waters become fresher and vice-versa. But how this change impacts phytoplankton in coastal, particularly harmful algal blooms (HABs), remains poorly understood. Here, we monitored a coastal bay for a decade and found a significant correlation between salinity decline and the increase of Karenia mikimotoi blooms. To examine the physiological linkage between salinity decreases and K. mikimotoi blooms, we compare chemical, physiological and multi-omic profiles of this species in laboratory cultures under high (33) and low (25) salinities. Under low salinity, photosynthetic efficiency and capacity as well as growth rate and cellular protein content were significantly higher than that under high salinity. More strikingly, the omics data show that low salinity activated the glyoxylate shunt to bypass the decarboxylation reaction in the tricarboxylic acid cycle, hence redirecting carbon from CO2 release to biosynthesis. Furthermore, the enhanced glyoxylate cycle could promote hydrogen peroxide metabolism, consistent with the detected decrease in reactive oxygen species. These findings suggest that salinity declines can reprogram metabolism to enhance cell proliferation, thus promoting bloom formation in HAB species like K. mikimotoi, which has important ecological implications for future climate-driven salinity declines in the coastal ocean with respect to HAB outbreaks.

Seasonal variation in diurnal blood pressure pattern.

AIMS: To explore the relationship between diurnal blood pressure (BP) pattern and season. METHODS: A total of 6765 eligible patients (average age 57.35 ± 15.53 years; male 51.8%; hypertensives 68.8%) from 1 October 2016 to 6 April 2022 were enrolled, who were divided into four dipper groups, dipper, non-dipper, riser, and extreme-dipper, according to the diurnal BP pattern calculated using their ambulatory BP monitoring data. The season which the patient was in was determined by the time of ambulatory BP monitoring examination. RESULTS: Among the 6765 patients, 2042 (31.18%) were grouped into dipper, 380 (5.6%) into extreme-dipper, 1498 (22.1%) into riser and 2845 (42.1%) into non-dipper. Only the dipper subjects showed age difference among seasons, with the average age significantly lower in winter. There was no seasonal difference in age for the other types. No seasonal difference was revealed in gender, BMI, hypertension or not. Diurnal BP patterns significantly differed among seasons (P < .001). Post hoc tests with Bonferroni correction indicated the significantly different diurnal BP pattern between any two seasons (P < .001), but not between spring and autumn (P = .257), and the significance of the P value was assessed at 0.008 (0.05/6) after Bonferroni correction. Multinomial logistic regression suggested season as an independent contributor to diurnal BP pattern. CONCLUSION: Diurnal BP pattern is influenced by season.

Lumbar spine segmentation method based on deep learning.

Aiming at the difficulties of lumbar vertebrae segmentation in computed tomography (CT) images, we propose an automatic lumbar vertebrae segmentation method based on deep learning. The method mainly includes two parts: lumbar vertebra positioning and lumbar vertebrae segmentation. First of all, we propose a lumbar spine localization network of Unet network, which can directly locate the lumbar spine part in the image. Then, we propose a three-dimensional XUnet lumbar vertebrae segmentation method to achieve automatic lumbar vertebrae segmentation. The method proposed in this paper was validated on the lumbar spine CT images on the public dataset VerSe 2020 and our hospital dataset. Through qualitative comparison and quantitative analysis, the experimental results show that the method proposed in this paper can obtain good lumbar vertebrae segmentation performance, which can be further applied to detection of spinal anomalies and surgical treatment.

Root-Bacteria Associations Boost Rhizosheath Formation in Moderately Dry Soil through Ethylene Responses.

The rhizosheath is a layer of soil around the root that provides a favorable environment for soil microbe enrichment and root growth. Rice (Oryza sativa) roots form rhizosheaths under moderate soil drying (MSD) conditions, but how the rhizosheath forms associations with microbes is unclear. To investigate rice rhizosheath formation under MSD, we employed a multiphasic approach, integrating data from high-throughput sequencing and root-bacteria interactions. Rice roots formed a pronounced rhizosheath under MSD, but not under continuous flooding regimens. Plant growth-promoting rhizobacteria of the Enterobacteriaceae were enriched in rhizosheaths of two different rice varieties, 'Gaoshan 1' (drought tolerant) and 'Nipponbare' (drought sensitive). RNA-sequencing analysis revealed that the ethylene pathway was induced in the rhizosheath-root system under MSD. Enterobacter aerogenes, a bacterium isolated from the rhizosheath, degrades the ethylene precursor 1-aminocyclopropane-1-carboxylate, thereby increasing rhizosheath formation. Furthermore, a 1-aminocyclopropane-1-carboxylate deaminase-deficient mutant of E. aerogenes failed to enhance rice rhizosheath formation. Our results suggest that root-bacteria associations substantially contribute to rhizosheath formation in rice under MSD conditions by mechanisms that involve the ethylene response. These data inform strategies to reduce water consumption in rice production, one of the most water-intensive human activities.

Abscisic acid mediates barley rhizosheath formation under mild soil drying by promoting root hair growth and auxin response.

Soil drying enhances root ABA accumulation and rhizosheath formation, but whether ABA mediates rhizosheath formation is unclear. Here, we used the ABA-deficient mutant Az34 to investigate molecular and morphological changes by which ABA could affect rhizosheath formation. Mild soil drying with intermittent watering increased rhizosheath formation by promoting root and root hair elongation. Attenuated root ABA accumulation in Az34 barley constrained the promotion of root length and root hair length by drying soil, such that Az34 had a smaller rhizosheath. Pharmacological experiments of adding fluridone (an ABA biosynthesis inhibitor) and ABA to drying soil restricted and enhanced rhizosheath formation respectively in Az34 and wild-type Steptoe barley. RNA sequencing suggested that ABA accumulation mediates auxin synthesis and responses and root and root hair elongation in drying soil. In addition, adding indole-3-acetic acid (IAA) to drying soil increased rhizosheath formation by promoting root and root hair elongation in Steptoe and Az34 barley. Together, these results show that ABA accumulation induced by mild soil drying enhance barley rhizosheath formation, which may be achieved through promoting auxin response.

Moderate water stress in rice induces rhizosheath formation associated with abscisic acid and auxin responses.

The rhizosheath is known to be beneficial for drought resistance in many plants, but the regulation of rhizosheath formation in rice plants is unclear. Here, we investigate rhizosheath formation in different rice varieties and root hair mutants. Our results showed that moderate water stress in rice induced rhizosheath formation. The soil porosity and water content were higher in the rice rhizosheath than in the rice bulk soil under moderate water stress. Additionally, rhizosheath formation in short root hair mutants was lower than in wild-type rice under moderate water stress. Moreover, transcriptomic results indicated that abscisic acid (ABA) and auxin were involved in root and root hair responses in rhizosheath formation. Further, blocking ABA and auxin pathways in wild type and in rhl1-1, the shortest root hair mutant, rhizosheath formation and root hair length were significantly decreased under moderate water stress. However, wild type plants maintained a higher root ABA content, root basipetal auxin transport, root hair length, and amount of rhizosheath than did rhl1-1. Our results suggest that moderate water stress in rice induces rhizosheath formation by modulating the ABA and auxin responses to regulate root and root hair growth, which may be used to breed rice varieties resistant to drought.

Rhizosheath formation and involvement in foxtail millet (Setaria italica) root growth under drought stress.

The rhizosheath, a layer of soil particles that adheres firmly to the root surface by a combination of root hairs and mucilage, may improve tolerance to drought stress. Setaria italica (L.) P. Beauv. (foxtail millet), a member of the Poaceae family, is an important food and fodder crop in arid regions and forms a larger rhizosheath under drought conditions. Rhizosheath formation under drought conditions has been studied, but the regulation of root hair growth and rhizosheath size in response to soil moisture remains unclear. To address this question, in this study we monitored root hair growth and rhizosheath development in response to a gradual decline in soil moisture. Here, we determined that a soil moisture level of 10%-14% (w/w) stimulated greater rhizosheath production compared to other soil moisture levels. Root hair density and length also increased at this soil moisture level, which was validated by measurement of the expression of root hair-related genes. These findings contribute to our understanding of rhizosheath formation in response to soil water stress.

Surface-Enhanced Raman Spectroscopy for Identification of Heavy Metal Arsenic(V)-Mediated Enhancing Effect on Antibiotic Resistance.

Bacterial antibiotic resistance poses a threat to global public health. Restricted usage of antibiotics does not necessarily prevent its continued emergence. Rapid and sensitive screening of triggers, in addition to antibiotic, and exploring the underlying mechanism are still major challenges. Herein, by developing a homogeneous vacuum filtration-based bacterial sample fabrication enabling high surface-enhanced Raman scattering (SERS) reproducibility across multiple bacterial samples and negating interfering spectral variations from inhomogeneous sample geometry and SERS enhancement, SERS was employed to study heavy metal arsenic [As(V)]-mediated antibiotic resistance in a robust, sensitive, and rapid fashion. Independent and robust spectral changes representing phenotypic bacterial responses, combined with multivariate analysis, clearly identified that As(V) enhanced antibiotic resistance to tetracycline (Tet). Similar spectral alteration profile to As(V) and Tet indicated that cross-resistance, whereby As(V)-induced bacterial resistance simultaneously blocked Tet action, could account for the enhanced resistance. The sensitive, robust, and rich phenotypic profile provided by SERS, combined with additional advantages in imposing no need to cultivate bacteria and single-cell sensitivity, can be further exploited to evaluate resistance-intervening factors in real microbiota.

Proteomic analysis provides new insights into the adaptive response of a dinoflagellate Prorocentrum donghaiense to changing ambient nitrogen.

Nitrogen (N) is the major nutrient limiting phytoplankton growth and productivity over large ocean areas. Dinoflagellates are important primary producers and major causative agents of harmful algal blooms in the ocean. However, very little is known about their adaptive response to changing ambient N. Here, we compared the protein profiles of a marine dinoflagellate Prorocentrum donghaiense grown in inorganic N-replete, N-deplete and N-resupplied conditions using 2-D fluorescence differential gel electrophoresis. The results showed that cell density, chlorophyll a and particulate organic N contents presented low levels in N-deplete cells, while particulate organic carbon content and glutamine synthetase (GS) activity maintained high levels. Comparison of the protein profiles of N-replete, N-deplete and N-resupplied cells indicated that proteins involved in photosynthesis, carbon fixation, protein and lipid synthesis were down-regulated, while proteins participating in N reallocation and transport activity were up-regulated in N-deplete cells. High expressions of GS and 60 kDa chaperonin as well as high GS activity in N-deplete cells indicated their central role in N stress adaptation. Overall, in contrast with other photosynthetic eukaryotic algae, P. donghaiense possessed a specific ability to regulate intracellular carbon and N metabolism in response to extreme ambient N deficiency.

Heavy Metal Induced Antibiotic Resistance in Bacterium LSJC7.

Co-contamination of antibiotics and heavy metals prevails in the environment, and may play an important role in disseminating bacterial antibiotic resistance, but the selective effects of heavy metals on bacterial antibiotic resistance is largely unclear. To investigate this, the effects of heavy metals on antibiotic resistance were studied in a genome-sequenced bacterium, LSJC7. The results showed that the presence of arsenate, copper, and zinc were implicated in fortifying the resistance of LSJC7 towards tetracycline. The concentrations of heavy metals required to induce antibiotic resistance, i.e., the minimum heavy metal concentrations (MHCs), were far below (up to 64-fold) the minimum inhibition concentrations (MIC) of LSJC7. This finding indicates that the relatively low heavy metal levels in polluted environments and in treated humans and animals might be sufficient to induce bacterial antibiotic resistance. In addition, heavy metal induced antibiotic resistance was also observed for a combination of arsenate and chloramphenicol in LSJC7, and copper/zinc and tetracycline in antibiotic susceptible strain Escherichia coli DH5α. Overall, this study implies that heavy metal induced antibiotic resistance might be ubiquitous among various microbial species and suggests that it might play a role in the emergence and spread of antibiotic resistance in metal and antibiotic co-contaminated environments.

Kimura Disease: A Detailed Analysis of Clinical and Radiological Manifestations in a Retrospective Case Series.

Background: Kimura disease (KD) is a rare chronic inflammatory disease that affects mainly young Asian men and is characterized by painless subcutaneous masses, lymphadenopathy, and elevated serum IgE levels. Despite its benign nature, KD poses a diagnostic and therapeutic challenge due to its rarity and clinical variability. Objective: This study aimed to provide a comprehensive analysis of the clinical and radiological features of KD in a retrospective case series, to assess treatment outcomes, and to discuss the implications for diagnosis and management. Methods: We retrospectively analyzed four histologically confirmed cases of KD admitted to Zhejiang Provincial People's Hospital from January 2018 to October 2023. Clinical and radiological data were retrospectively analyzed, and imaging findings were analyzed by two neuroradiologists to determine lesion characteristics and contrast enhancement patterns. Results: Our findings showed that the patients were predominantly male, with a mean age of 43 years and an age range of 13-71 years. All patients presented with painless subcutaneous masses and three of them had peripheral blood eosinophilia and elevated serum IgE levels. Radiographically, the lesions were predominantly ill-defined with heterogeneous enhancement, accompanied by subcutaneous fat atrophy. Complete surgical excision and oral corticosteroids were effective treatments, and no recurrence was noted during follow-up. Conclusion: KD should be considered in the differential diagnosis of painless subcutaneous masses in the head and neck region, especially in the presence of eosinophilia and elevated IgE levels. Our findings contribute to the understanding of KD's clinical and radiological spectrum and highlight the need for long-term follow-up due to the risk of recurrence.

Impact of Discharge Planning Combined with "Internet Home Ostomy Care Platform'' in Patients with Permanent Colostomy after Rectal Cancer Surgery.

AIM: Patients with permanent colostomy need continuous nursing management measures. Therefore, this study aimed to investigate the impact of discharge planning combined with "Internet home ostomy care platform'' on post-discharge complications, self-management abilities, quality of life, and satisfaction of patients with permanent colostomy after rectal cancer surgery. METHODS: This retrospective analysis included 72 rectal cancer patients who underwent permanent colostomy in Zhejiang Provincial People's Hospital between January 2021 and December 2021. Patients receiving routine nursing management were included in the control group (n = 36), and those receiving discharge planning combined with "Internet home ostomy care platform'' were included in the study group (n = 36). We collected baseline data, complication rate, self-management behavior questionnaire for Chinese enterostomy patients (SBQ-CEP), and Chinese version of the City of Hope Quality of Life-Ostomy Questionnaire (COH-QOL-OQ) and Medical Experience Scale for Outpatient Care of Enterostomy (MES-OCE) score. The complication rate, self-management ability, quality of life, and satisfaction of the two groups were statistically compared and analyzed. RESULTS: The study group demonstrated significantly higher medical compliance behavior, dietary behavior, symptom management behavior, psychosocial behavior, information management behavior scores, and SBQ-CEP total scores compared to the control group six months after discharge (p < 0.05). However, the study group showed a significantly lower incidence of complications than the control group at 1 week, 2 weeks, 1 month, 3 months, and 6 months after discharge (p < 0.05). Furthermore, the study group demonstrated significantly lower psychological well-being, physical well-being, spiritual well-being, social well-being scores, and COH-QOL-OQ total scores compared to the control group 6 months after discharge (p < 0.05). Additionally, the study group indicated significantly higher environment and process, service attitude, health guidance, diagnosis and treatment effect, overall evaluation of treatment experience scores, and MES-OCE total scores compared to the control group 6 months after discharge (p < 0.05). CONCLUSIONS: Discharge planning combined with "Internet home ostomy care platform'' can effectively reduce the risk of complications in patients with permanent colostomy after rectal cancer surgery. It improves patients' self-management abilities, quality of life, and satisfaction. This finding provides an ongoing guarantee for the quality of rehabilitation at home for patients with permanent colostomy.

Intermediate product control in cascade reaction for one-pot production of ε-caprolactone by Escherichia coli.

ε-Caprolactone is an important non-toxic compound for polymer synthesis like polycaprolactone which has been widely used in drug delivery and degradable plastics. To meet the demand for a green economy, a bi-enzymatic cascade, consisting of an alcohol dehydrogenase (ADH) and a cyclohexanone monooxygenase (CHMO), was designed and introduced into Escherichia coli to synthesize ε-caprolactone from cyclohexanol with a self-sufficient NADPH-cofactor regeneration system. To further improve the catalytic efficiency, a carbonyl group-dependent colorimetric method using inexpensive 2,4-dinitrophenylhydrazine (DNPH) was developed for assay of cyclohexanone, an intermediate production of cascade reaction. It can be used to screen mutant strains with high catalytic efficiency from high-throughput library by detecting the absorbance value in microtiter plates (MTP) instead of gas chromatography (GC) analysis. Moreover, an RBS combinatorial library was constructed for balancing the expression of ADH and CHMO from two independent transcriptional units. After the high-throughput screening based on intermediate product control, an optimal variant with higher substrate tolerance and long-term stability was obtained from RBS combinatorial library. Through a fed-batch process, ε-caprolactone production reached 148.2 mM after 70 h of reaction under the optimized conditions, which was the highest yield achieved to date.

Auxin-producing bacteria promote barley rhizosheath formation.

The rhizosheath, or the layer of soil closely adhering to roots, can help plants to tolerate drought under moderate soil drying conditions. Rhizosheath formation is the result of poorly understood interactions between root exudates, microbes, and soil conditions. Here, we study the roles played by the soil microbiota in rhizosheath formation in barley (a dry crop). We show that barley rhizosheath formation is greater in acid soil than in alkaline soil, and inoculation with microbiota from acid soil enhances rhizosheath formation in alkaline soil. The rhizosheath-promoting activity is associated with the presence of Flavobacteriaceae and Paenibacillaceae bacteria that express genes for biosynthesis of indole-3-acetic acid (IAA, a common auxin), as determined by metagenomics and metatranscriptomics. Two bacterial strains isolated from rhizosheath (Chryseobacterium culicis and Paenibacillus polymyxa) produce IAA and enhance barley rhizosheath formation, while their IAA-defective mutants are unable to promote rhizosheath formation. Co-inoculation with the IAA-producing strains enhances barley grain yield in field experiments through an increase in spike number. Our findings contribute to our understanding of barley rhizosheath formation, and suggest potential strategies for crop improvement.

Risk and prognosis of secondary bladder cancer after post-operative radiotherapy for gynecological cancer.

The aim of this study was to investigate the impacts of radiation therapy (RT) on the occurrence risk of secondary bladder cancer (SBC) and on the patients' survival outcome after being diagnosed with gynecological cancer (EC). The data was obtained from the SEER database between 1973 and 2015. Chi-squared test was used to compare the clinicopathological characteristics among the different groups. Fine and Gray's competing risk model was used to assess the cumulative incidence and occurrence risk of SBC in GC survivors. Kaplan-Meier method was utilized for survival analysis. A total of 123,476 GC patients were included, among which 31,847 (25.8%) patients received RT while 91629 (74.2%) patients did not. The cumulative incidence of SBC was 1.59% or 0.73% among patients who had received prior GC specific RT or not, respectively. All EBRT (standardized incidence ratio (SIR) =2.49, 95% CI [2.17-2.86]), brachytherapy (SIR =1.96, 95% CI [1.60-2.38]), and combinational RT modality groups (SIR =2.73, 95% CI [2.24-3.28]) had dramatically higher SBC incidence as compared to the US general population. Receiving EBRT (HR = 2.83, 95% CI [2.34-3.43]), brachytherapy (HR = 2.17, 95% CI [1.67-2.82]), and combinational RT modality (HR = 2.97, 95% CI [2.34-3.77]) were independent risk factors for SBC development. Survival detriment was observed in SBC patients who received RT after GC diagnosis, as compared to those who did not receive RT. In conclusion, patients who underwent RT after GC had an increased risk of developing bladder as a secondary primary cancer. A long-term surveillance for SBC occurrence is necessary for GC patients who have received prior RT.

Metastasis patterns and prognosis of octogenarians with metastatic breast cancer: A large-cohort retrospective study.

BACKGROUND: Breast cancer may differ biologically in patients aged over 80 years. The objective of the current study was to analyze the metastasis patterns and prognosis of elderly patients with metastatic breast cancer (MBC) and compare it to patients of other ages. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was utilized to select MBC patients from 2010 to 2015. Chi-squared test was used to compare clinicopathological characteristics among different aged groups. The Kaplan-Meier method and multivariate Cox model were utilized for survival analysis. RESULTS: A total of 10479 MBC patients were included, among which 1036 (9.9%) patients were aged over 80 years. Compared with other aged group, the elderly patients tended to have a higher proportion of HR+/Her2- subtype, white race, lower tumor differentiation, and receive less treatment, including surgery, chemotherapy and radiotherapy (P< 0.001). MBC patients with different age presented with distinctive metastatic patterns. The older patients were more likely to have lung metastasis, but less likely to have bone, brain, liver and multiple sites metastasis than the younger group (P <0.001). The proportion of TNBC subtype increased substantially in the older patients with brain metastasis, compared to the younger and middle-aged group. The old age was demonstrated to significantly associate with worse prognosis of MBC patients. Additionally, our findings also showed that older MBC patients could achieve dramatical overall survival benefit from surgery (HR = 0.58; P <0.001) and chemotherapy (HR = 0.59; P <0.001), but not the radiotherapy (HR = 0.96; P = 0.097). CONCLUSION: The elderly MBC patients presented with distinctive metastatic patterns, clinical characteristics, and prognostic outcomes compared with younger patients. Our findings could assist clinicians in making appropriate therapeutic decision.

Coordination of root auxin with the fungus Piriformospora indica and bacterium Bacillus cereus enhances rice rhizosheath formation under soil drying.

Moderate soil drying (MSD) is a promising agricultural technique that can reduce water consumption and enhance rhizosheath formation promoting drought resistance in plants. The endophytic fungus Piriformospora indica (P. indica) with high auxin production may be beneficial for rhizosheath formation. However, the integrated role of P. indica with native soil microbiome in rhizosheath formation is unclear. Here, we investigated the roles of P. indica and native bacteria on rice rhizosheath formation under MSD using high-throughput sequencing and rice mutants. Under MSD, rice rhizosheath formation was significantly increased by around 30% with P. indica inoculation. Auxins in rice roots and P. indica were responsible for the rhizosheath formation under MSD. Next, the abundance of the genus Bacillus, known as plant growth-promoting rhizobacteria, was enriched in the rice rhizosheath and root endosphere with P. indica inoculation under MSD. Moreover, the abundance of Bacillus cereus (B. cereus) with high auxin production was further increased by P. indica inoculation. After inoculation with both P. indica and B. cereus, rhizosheath formation in wild-type or auxin efflux carrier OsPIN2 complemented line rice was higher than that of the ospin2 mutant. Together, our results suggest that the interaction of the endophytic fungus P. indica with the native soil bacterium B. cereus favors rice rhizosheath formation by auxins modulation in rice and microbes under MSD. This finding reveals a cooperative contribution of P. indica and native microbiota in rice rhizosheath formation under moderate soil drying, which is important for improving water use in agriculture.

Rhizosheath microbes induce root immune response under soil drying.

The rhizosheath is an important drought-adaptive trait in roots of many angiosperms and has been regarded as a potential trait for future agricultural sustainability. In recent studies, we found that rice roots could form a pronounced rhizosheath under moderate soil drying (MSD) but not under continuous flooding irrigation (CF). The formation of rhizosheaths substantially changes the microbial community structure in endosphere root tissues and the rhizosphere in rice, which may induce a plant immune response. However, the manner by which the formation of rhizosheaths regulates the immune system of roots remains largely unknown. Here, we have analyzed the root transcriptomes of drought-tolerant rice and drought-sensitive rice under both MSD (rhizosheath-root) and CF (root without rhizosheath) conditions. Our results suggest that rhizosheath-associated microbes may trigger plant immune pathways in root under MSD, including the first line of defense component pattern-triggered immunity and the second line of defense component effector-triggered immunity. These data expand our understanding of rhizosheath-associated microbes and plant interactions.

Conversion of tannery solid waste to an adsorbent for high-efficiency dye removal from tannery wastewater: A road to circular utilization.

The high value-added use of tannery solid waste and elimination of tannery liquid waste in the leather-making industry have attracted widespread attention. In this study, a MgO-doped biochar (MgO/BC) adsorbent was successfully prepared by utilizing tannery solid waste (i.e., non-tanned hide wastes) as the biomass material for dye removal from tannery wastewater. Characterization results indicated that MgO was uniformly embedded into the porous BC structure. The adsorption capacity of acid orange II by MgO/BC reached up to 448.4 mg g-1, which drastically exceeded the pure BC and other reported adsorbents. The adsorption behavior of acid orange II by MgO/BC matched nicely with Langmuir isotherm and pseudo-second-order kinetic model. This satisfactory adsorption capacity of MgO/BC for acid orange II was mainly due to the large specific surface area and the enhanced electrostatic interaction. According to the BET, zeta potential and XPS analysis, the possible mechanism towards acid orange II removal was attributed to the pore filling, surface complexation, electrostatic attraction and π-π interaction. In addition, MgO/BC showed the efficient removal towards anionic dyes from actual tannery wastewater. This work could provide guidance for the value-added utilization of tannery solid waste and a practical way to remove dyes from tannery wastewater.

Synergistic antimicrobial activity of a novel cationic micelle L/D2 and imipenem against multidrug-resistant Acinetobacter baumannii.

Background: The multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) has become one of the most important pathogens of nosocomial infection due to widespread use of broad spectrum antimicrobial drugs and immunosuppressor therapy. As polymyxins resistance emerges, developing novel effective antibacterial agents capable of overcoming multidrug resistance is urgently needed. Methods: In this study, biodegradable triblock copolymers of polyethylene glycol (PEG), guanidinium-functionalized polycarbonate and polylactide, PEG-PGC20-PLLA20 (L2) and PEG-PGC20-PDLA20 (D2), were utilized as antibacterial agents. Results: The copolymers self-assemble into micellar nanoparticles (L/D2), and exhibit broad-spectrum antibacterial activity against 20 clinically isolated multidrug-resistant A. baumannii strains. L/D2 had more rapid killing kinetics than conventional antibiotics imipenem and ceftazidime, and exhibited potent anti-biofilm activity. Repeated use of L/D2 did not induce drug resistance. From scanning electron microscopy and nucleic acid release analyses, L/D2 showed membrane-lytic mechanism. We also demonstrated that L/D2 was synergistically active with imipenem against MDR A. baumannii strains. Additionally, strong synergistic antibacterial activity was also observed for the combined use of L/D2 and imipenem in a MDR A. baumannii abdominal infection mouse model. Conclusions: Therefore, the combination of L/D2 and imipenem might be an alternative option for the prevention of nosocomial infection caused by A. baumannii.