Two orthogonal differentiation gradients locally coordinate fruit morphogenesis.

Morphogenesis requires the coordination of cellular behaviors along developmental axes. In plants, gradients of growth and differentiation are typically established along a single longitudinal primordium axis to control global organ shape. Yet, it remains unclear how these gradients are locally adjusted to regulate the formation of complex organs that consist of diverse tissue types. Here we combine quantitative live imaging at cellular resolution with genetics, and chemical treatments to understand the formation of Arabidopsis thaliana female reproductive organ (gynoecium). We show that, contrary to other aerial organs, gynoecium shape is determined by two orthogonal, time-shifted differentiation gradients. An early mediolateral gradient controls valve morphogenesis while a late, longitudinal gradient regulates style differentiation. Local, tissue-dependent action of these gradients serves to fine-tune the common developmental program governing organ morphogenesis to ensure the specialized function of the gynoecium.

Progress and Challenges in Tumor Ferroptosis Treatment Strategies: A Comprehensive Review of Metal Complexes and Nanomedicine.

Ferroptosis is a new form of regulated cell death featuring iron-dependent lipid peroxides accumulation to kill tumor cells. A growing body of evidence has shown the potential of ferroptosis-based cancer therapy in eradicating refractory malignancies that are resistant to apoptosis-based conventional therapies. In recent years, studies have reported a number of ferroptosis inducers that can increase the vulnerability of tumor cells to ferroptosis by regulating ferroptosis-related signaling pathways. Encouraged by the rapid development of ferroptosis-driven cancer therapies, interdisciplinary fields that combine ferroptosis, pharmaceutical chemistry, and nanotechnology are focused. First, the prerequisites and metabolic pathways for ferroptosis are briefly introduced. Then, in detail emerging ferroptosis inducers designed to boost ferroptosis-induced tumor therapy, including metal complexes, metal-based nanoparticles, and metal-free nanoparticles are summarized. Subsequently, the application of synergistic strategies that combine ferroptosis with apoptosis and other regulated cell death for cancer therapy, with emphasis on the use of both cuproptosis and ferroptosis to induce redox dysregulation in tumor and intracellular bimetallic copper/iron metabolism disorders during tumor treatment is discussed. Finally, challenges associated with clinical translation and potential future directions for potentiating cancer ferroptosis therapies are highlighted.

Re-recognition of the role of roughness in keloid assessment.

BACKGROUND: Under visual observation, keloids are more rough than normal skin. This roughness may be used to assess the activity and severity of keloids but lacks the support of objective and accurate evidence. The purpose of this study was to verify the role of roughness in the development of keloids and to clarify the advantage of roughness in the comprehensive assessment of keloids. METHODS: Patients with keloids who attended Peking Union Medical College Hospital were recruited. Keloids were classified into progressive, stable, and atrophic stages based on the change in size over the past year and blood perfusion. The keloids were evaluated using the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS). The roughnesses of the keloid and normal skin were measured using the Phaseshift Rapid In vivo Measurement Of the Skin (PRIMOS), and blood perfusion was measured using laser speckle contrast imaging (LSCI). RESULTS: Thirty-three patients with a total of 81 keloids were included. The surface roughness values Sa, Sq, and Sz of the keloid region were 243.70 (143.85-328.05), 316.20 (179.85-475.20), and 1708.20 (1098.30-4087.20), respectively, which were 4.87, 4.80, and 3.08 times higher than those of normal skin. There were significant differences in roughness among the different keloid stages. A significantly strong correlation between roughness and other assessed indices was found. CONCLUSIONS: Roughness as a morphological characteristic is of great value in the evaluation of keloids. It is recommended as an important examination for keloids.

Associations of the Mediterranean-DASH Intervention for Neurodegenerative Delay diet with brain structural markers and their changes.

INTRODUCTION: The associations of the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet with brain structural changes are unclear. METHODS: Among 26,466 UK Biobank participants, a 15-point MIND score was calculated from 24-hour diet recalls from 2009 to 2012. We assessed its associations with 17 magnetic-resonance-derived brain volumetric markers and their longitudinal changes and explored whether genetic factors modify the associations. RESULTS: Higher MIND adherence was associated with larger volumes of thalamus, putamen, pallidum, hippocampus, and accumbens (beta per 3-unit increment ranging from 0.024 to 0.033) and lower white matter hyperintensities (P-trends < 0.05), regardless of genetic predispositions of Alzheimer's disease. MIND score was not associated with their longitudinal changes (P > 0.05) over a median of 2.2 years among participants with repeated imaging assessments (N = 2963), but was associated with slower atrophy in putamen (beta: 0.026, P-trend = 0.044) and pallidum (beta: 0.030, P-trend = 0.033) among APOE Îµ4 non-carriers (N = 654). DISCUSSION: The MIND diet showed beneficial associations with certain brain imaging markers, and its associations with long-term brain structural changes warrants future investigation. HIGHLIGHTS: Adherence to the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet was significantly associated with higher volumes and larger gray matter volumes in certain brain regions in UK adults, and the associations were not modified by genetic factors. No significant associations were observed between MIND diet and longitudinal changes in the investigated brain structural markers over a median of 2.2 years. Higher MIND score was significantly associated with slower atrophy in the putamen and pallidum among APOE Îµ4 non-carriers.

Progression and trajectory network of age-related functional impairments and their combined associations with mortality.

Age-related functional impairments (ARFIs) contribute to the loss of independence in older adults, but their progressions, interrelations, and combined relations with mortality are largely unknown. We conducted a prospective study among 17,914 participants in the Health and Retirement Study (2000-2020). The incidence rates of visual impairment, hearing impairment, physical frailty, and cognitive impairment increased exponentially with age, while those of restless sleep and depression increased relatively slowly. These ARFIs were associated with each other in temporal sequence and constituted a hazard network. We observed a dose-response relationship between the number of ARFIs and mortality risk, and the dyads involving physical frailty demonstrated the strongest associations with mortality. Our findings may assist in the identification of individuals at higher mortality risk and highlight the potential for future investigations to explore the impact of multiple ARFIs in aging.

Pathogenic Bacteria Are the Primary Determinants Shaping PM2.5-Borne Resistomes in the Municipal Food Waste Treatment System.

Bioaerosol pollution poses a substantial threat to human health during municipal food waste (FW) recycling. However, bioaerosol-borne antibiotic-resistant genes (ARGs) have received little attention. Herein, 48 metagenomic data were applied to study the prevalence of PM2.5-borne ARGs in and around full-scale food waste treatment plants (FWTPs). Overall, FWTP PM2.5 (2.82 ± 1.47 copies/16S rRNA gene) harbored comparable total abundance of ARGs to that of municipal wastewater treatment plant PM2.5 (WWTP), but was significantly enriched with the multidrug type (e.g., AdeC/I/J; p < 0.05), especially the abundant multidrug ARGs could serve as effective indicators to define resistome profiles of FWTPs (Random Forest accuracy >92%). FWTP PM2.5 exhibited a decreasing enrichment of total ARGs along the FWTP-downwind-boundary gradient, eventually reaching levels comparable to urban PM2.5 (1.46 ± 0.21 copies/16S rRNA gene, N = 12). The combined analysis of source-tracking, metagenome-assembled genomes (MAGs), and culture-based testing provides strong evidence that Acinetobacter johnsonii-dominated pathogens contributed significantly to shaping and disseminating multidrug ARGs, while abiotic factors (i.e., SO42-) indirectly participated in these processes, which deserves more attention in developing strategies to mitigate airborne ARGs. In addition, the exposure level of FWTP PM2.5-borne resistant pathogens was about 5-11 times higher than those in urban PM2.5, and could be more severe than hospital PM2.5 in certain scenarios (<41.53%). This work highlights the importance of FWTP in disseminating airborne multidrug ARGs and the need for re-evaluating the air pollution induced by municipal FWTP in public health terms.

Multiple Sensory Impairments in Relation to Cognitive Function: Two Nationwide Cross-sectional Studies.

INTRODUCTION: Sensory impairments (SIs, including visual, hearing, olfactory, and taste impairments) have been individually associated with age-related cognitive function. Little is known regarding their combined associations with cognitive function. METHODS: We included 2,931 participants (mean age of 69.1 years) from the National Health and Nutrition Examination Survey (NHANES, 2011-2014) and 10,785 participants (mean age of 70.2 years) from the National Health Interview Survey (NHIS, 2021). Status of visual, hearing, olfactory, and taste functions were self-reported in structured questionnaires. In NHANES, cognitive function was objectively measured by a battery of tests, including memory, verbal fluency, and processing speed. NHIS participants answered a single question about subjective cognitive complaints (SCC). We used regression models to assess the relation of the total number and the individual sensory impairments to z-scores of cognitive domains (linear regression) in NHANES and to SCC (logistic regression) in NHIS. RESULTS: A larger number of SI was related to poorer domain-specific cognitive function (all Ptrend <0.05), including memory (beta each additional SI = -0.12, 95% confidence interval: -0.17 to -0.08), verbal fluency (-0.05, -0.10 to -0.01), and processing speed (-0.13, -0.16 to -0.09). In NHIS, each additional SI was related to 96% higher odds of SCC. We also observed independent associations of sensory impairments (except olfactory impairment) with specific cognitive domains. In addition, each individual SI was associated with higher odds of SCC (the odds ratios ranged from 1.30 to 1.78). CONCLUSION: A larger number of SI was related to worse cognitive function and higher odds of SCC.

Insight into the responses of antibiotic resistance genes in microplastic biofilms to zinc oxide nanoparticles and zinc ions pressures in landfill leachate.

Microplastic (MP) biofilms are hotspots of antibiotic resistance genes (ARGs) in landfill environment. MP biofilms in landfill leachate coexist with heavy metals and metallic nanoparticles (NPs) that considered to be the selective agents of ARGs. However, the effects of these selective pressures on ARGs in MP biofilms and their differences in MP-surrounding leachate have not been well understood. Herein, the changes of ARG abundances in MP biofilms and corresponding leachate under zinc oxide (ZnO) NPs and zinc ion (Zn2+) pressures were comparatively analyzed. The presence of ZnO NPs and Zn2+ promoted the enrichment of ARGs in MP biofilms, and the enrichment was more pronounced in ZnO NPs groups. ZnO NPs and especially Zn2+ mainly decreased the abundances of ARGs in leachate. The increase of integron abundances and reactive oxygen species production in MP biofilms implied the enhanced potential for horizontal transfer of ARGs under ZnO NPs and Zn2+ pressures. Meanwhile, the co-occurrence pattern between ARGs and bacterial genera in MP biofilms with more diverse potential ARG hosts was more complex than in leachate, and the enrichment of ARG-hosting bacteria in MP biofilms under ZnO NPs and Zn2+ pressures supported the enrichment of ARGs.

Associations between underlying diseases with COVID-19 and its symptoms among adults: a cross-sectional study.

Background: Specific underlying diseases were reported to be associated with severe COVID-19 outcomes, but little is known about their combined associations. The study was aimed to assess the relations of number of and specific underlying diseases to COVID-19, severe symptoms, loss of smell, and loss of taste. Methods: A total of 28,204 adult participants in the National Health Interview Survey 2021 were included. Underlying diseases (including cardiovascular diseases, cancer, endocrine diseases, respiratory diseases, neuropsychiatric diseases, liver and kidney diseases, fatigue syndrome, and sensory impairments), the history of COVID-19, and its symptoms were self-reported by structured questionnaires. Multivariable logistic regression models were used to assess the combined relation of total number of underlying diseases to COVID-19 and its symptoms, while mutually adjusted logistic models were used to examine their independent associations. Results: Among the 28,204 participants (mean ± standard deviation: 48.2 ± 18.5 years), each additional underlying disease was related to 33, 20, 37, and 39% higher odds of COVID-19 (odds ratio [OR]: 1.33, 95% confidence interval [CI]: 1.29-1.37), severe symptoms (OR: 1.20, 95% CI: 1.12-1.29), loss of smell (OR: 1.37, 95% CI: 1.29-1.46), and loss of taste (OR: 1.39, 95% CI: 1.31-1.49). In addition, independent associations of sensory impairments with COVID-19 (OR: 3.73, 95% CI: 3.44-4.05), severe symptoms (OR: 1.37, 95% CI: 1.13-1.67), loss of smell (OR: 8.17, 95% CI: 6.86-9.76), and loss of taste (OR: 6.13, 95% CI: 5.19-7.25), cardiovascular diseases with COVID-19 (OR: 1.13, 95% CI: 1.03-1.24), neuropsychiatric diseases with severe symptoms (OR: 1.41, 95% CI: 1.15-1.74), and endocrine diseases with loss of taste (OR: 1.28, 95% CI: 1.05-1.56) were observed. Conclusion: A larger number of underlying diseases were related to higher odds of COVID-19, severe symptoms, loss of smell, and loss of taste in a dose-response manner. Specific underlying diseases might be individually associated with COVID-19 and its symptoms.

Epidemiological characteristics of norovirus infection in pediatric patients during the COVID-19 pandemic.

To assess the epidemiological characteristics of norovirus infection. We included 5564 patients under the age of 18 years who visited the hospital in which the study took place from December 2020 to November 2022 with a primary diagnosis of acute diarrhea. Clinical information was extracted from the electronic health record system. We calculated the prevalence of norovirus infection by age, gender, season, year, and type of patients. A nonlinear association between age and prevalence rates was assessed using a restricted cubic spline regression model. A total of 5564 patients completed the test for human norovirus, among whom 1442 (25.9%) tested positive. The prevalence of norovirus infection was significantly lower in 2022 than in 2021 (35.9% vs. 53.7%, p < 0.001), and the highest prevalence was observed in winter (35.1%) and then followed by autumn (27.5%). Regarding the age pattern, the highest rate was seen in children aged 1-3 years (37.5%). Children at age 1.5 years may have the highest risk of having norovirus infection (Pnonlinear < 0.001). The prevalence of norovirus infection of norovirus during the COVID-19 pandemic was similar to that before the pandemic shown in literatures. A relatively high rate was observed in cool seasons and in younger children (i.e., 1-3 years).

Non-negligible health risks caused by inhalation exposure to aldehydes and ketones during food waste treatments in megacity Shanghai.

Aldehydes and ketones in urban air continue to receive regulatory and scientific attention for their environmental prevalence and potential health hazard. However, current knowledge of the health risks and losses caused by these pollutants in food waste (FW) treatment processes is still limited, especially under long-term exposure. Here, we presented the first comprehensive assessment of chronic exposure to 21 aldehydes and ketones in urban FW-air environments (e.g., storage site, mechanical dewatering, and composting) by coupling substantial measured data (383 samples) with Monte Carlo-based probabilistic health risk and impact assessment models. The results showed that acetaldehyde, acetone, 2-butanone and cyclohexanone were consistently the predominant pollutants, although the significant differences in pollution profiles across treatment sites and seasons (Adonis test, P < 0.001). According to the risk assessment results, the estimated cancer risk (CR; mean range: 1.6 × 10-5-1.12 × 10-4) and non-cancer risk (NCR; mean range: 2.98-22.7) triggered by aldehydes and ketones were both unacceptable in most cases (CR: 37.8%-99.3%; NCR: 54.2%-99.8%), and even reached the limit of concern to CR (1 × 10-4) in some exposure scenarios (6.18%-16.9%). Application of DALYs (disability adjusted life years) as a metric for predicting the damage suggested that exposure of workers to aldehydes and ketones over 20 years of working in FW-air environments could result in 0.02-0.14 DALYs per person. Acetaldehyde was the most harmful constituent of all targeted pollutants, which contributed to the vast majority of health risks (>88%) and losses (>90%). This study highlights aldehydes and ketones in FW treatments may be the critical pollutants to pose inhalation risks.

Genome-centric metagenomics revealed functional traits in high-solids anaerobic co-digestion of restaurant food waste, household food waste and rice straw.

High-solids anaerobic co-digestion (HS-AcoD) of food waste (FW) and other organic wastes is an effective option to improve the biogas production and system stability compared to mono-digestion. However, the clean and sustainable HS-AcoD strategy for FW and associated microbial functional traits have not been well explored. Here, HS-AcoD of restaurant food waste (RFW), household food waste (HFW) and rice straw (RS) were performed. Results showed that the maximum synergy index (SI) of 1.28 were achieved when the volatile solids ratio of RFW, HFW and RS was 0.45:0.45:0.1. HS-AcoD alleviated the acidification process by regulating metabolism associated with hydrolysis and volatile fatty acids formation. The synergistic relationship between syntrophic bacteria and Methanothrix sp., and the enhanced metabolic capacity associated with the acetotrophic and hydrogenotrophic pathways dominated by Methanothrix sp., provided a further explanation of the synergistic mechanism. These findings advance the knowledge about microbial mechanisms underlying the synergistic effect of HS-AcoD.

Dietary Intake Levels of Iron, Copper, Zinc, and Manganese in Relation to Cognitive Function: A Cross-Sectional Study.

Background: Previous studies have related circulating levels of trace metal elements, of which dietary intake is the major source, to cognitive outcomes. However, there are still relatively few studies evaluating the associations of dietary intake levels of iron, copper, zinc, and manganese with cognitive function (CF). Methods: We leveraged the data of 6863 participants (mean [standard deviation] age = 66.7 [10.5] years) in the Health and Retirement Study (2013/2014). Dietary intake levels of iron, copper, zinc, and manganese were calculated from a semi-quantitative food frequency questionnaire. CF was assessed using the 27-point modified Telephone Interview for Cognitive Status (TICS). We used linear regression models to calculate the mean differences in global CF scores by quintiles of dietary intake levels of trace metal elements. Results: Among the study participants, the mean (SD) values of daily dietary intake were 13.3 (6.3) mg for iron, 1.4 (0.7) mg for copper, 10.7 (4.6) mg for zinc, and 3.3 (1.6) mg for manganese. Compared with the lowest quintile of dietary iron intake (<8.1 mg), the highest quintile (≥17.7 mg) was associated with a lower cognitive score (-0.50, -0.94 to -0.06, P-trend = 0.007). Higher dietary copper was significantly associated with poorer CF (P-trend = 0.002), and the mean difference in cognitive score between extreme quintiles (≥1.8 vs. <0.8 mg) was -0.52 (95% confidence interval: -0.94 to -0.10) points. We did not observe significant associations for dietary intake of zinc (P-trend = 0.785) and manganese (P-trend = 0.368). Conclusion: In this cross-sectional study, higher dietary intake of iron and copper was related to worse CF, but zinc and manganese intake levels were not significantly associated with CF.

Research progress of hydrogels as delivery systems and scaffolds in the treatment of secondary spinal cord injury.

Secondary spinal cord injury (SSCI) is the second stage of spinal cord injury (SCI) and involves vasculature derangement, immune response, inflammatory response, and glial scar formation. Bioactive additives, such as drugs and cells, have been widely used to inhibit the progression of secondary spinal cord injury. However, the delivery and long-term retention of these additives remain a problem to be solved. In recent years, hydrogels have attracted much attention as a popular delivery system for loading cells and drugs for secondary spinal cord injury therapy. After implantation into the site of spinal cord injury, hydrogels can deliver bioactive additives in situ and induce the unidirectional growth of nerve cells as scaffolds. In addition, physical and chemical methods can endow hydrogels with new functions. In this review, we summarize the current state of various hydrogel delivery systems for secondary spinal cord injury treatment. Moreover, functional modifications of these hydrogels for better therapeutic effects are also discussed to provide a comprehensive insight into the application of hydrogels in the treatment of secondary spinal cord injury.

Longitudinal body weight dynamics in relation to cognitive decline over two decades: A prospective cohort study.

OBJECTIVE: The aim of this study was to investigate the associations of body weight change (BWC) and body weight variability (BWV) with changes in cognitive function. METHODS: In 10,340 Health and Retirement Study participants (mean age: 68.0 years), body weight was reported biennially from 1993/1994 to 2016, and cognitive function was measured biennially from 1998 to 2016. We calculated BWC and BWV as the slope and root-mean-square error by regressing body weight on time for each individual. BWC was categorized by quintiles (Q): stable weight (Q2 to Q4), weight loss (Q1), and weight gain (Q5). BWV was categorized by tertiles. We used linear mixed regression models to assess associations with cognitive change. RESULTS: Compared with stable weight (median: 0 kg/y), weight loss (median: -1.3 kg/y) predicted faster cognitive decline as demonstrated by mean difference of -0.023 (95% CI: -0.027 to -0.019) in cognitive change z score per year, whereas weight gain (median: 1 kg/y) was related to slower cognitive decline (ß = 0.006; 95% CI: 0.003 to 0.009). Larger BWV was also associated with faster cognitive decline (ß comparing the top with bottom tertile = -0.003; 95% CI: -0.006 to -0.0002). Similar associations were observed for episodic and working memory. CONCLUSIONS: Weight loss and large BWV over a long time independently predicted faster cognitive decline in middle-aged and older adults, underscoring the importance of long-term dynamic body weight monitoring.

Epidemiological and genetic characteristics of respiratory syncytial virus infection in children from Hangzhou after the peak of COVID-19.

BACKGROUND: Respiratory syncytial virus (RSV) is one of the main pathogens that causes acute lower respiratory tract infection (ARTI) in infants. During the Coronavirus Disease 2019 (COVID-19) pandemic, although strict interventions have been implemented, RSV infection has not decreased. OBJECTIVES: To study the epidemiological and genetic characteristics of RSV circulating in Hangzhou after the peak of COVID-19. METHODS: A total of 1225 nasopharyngeal swabs were collected from outpatients with ARTIs from July 2021 to January 2022 in The Children's Hospital, Zhejiang University School of Medicine. RESULTS: A total of 267 (21.79%) of the 1225 samples were RSV positive. There was no gender bias. However, an obvious age preference for infection was observed, and children aged 3-6 years were more susceptible, which was very different from previous RSV pandemic seasons. Phylogenetic analysis of 115 sequenced RSV isolates showed that all the RSV-A viruses belong to the ON1 subtype, which could be clustered into three clusters. While all the RSV-B viruses belong to BA9. Further analysis of the mutations highlights the fixation of ten mutations, which should be given extra attention regarding their biological properties. CONCLUSION: The incidence of RSV infection in preschool children reported in this study is high. Phylogenetic analysis showed that the subtype A ON1 genotype was the dominant strain in Hangzhou from July 2021 to January 2022.

Profiles and predictive value of cytokines in children with human metapneumovirus pneumonia.

BACKGROUND: Human metapneumovirus (HMPV) is an important cause of respiratory tract infections in young children. Early innate immune response to HMPV is focused on induction of antiviral interferons (IFNs) and other pro-inflammatory cytokines that are critical for the formation of adaptive immune responses. To evaluate the predictive value of Th1/Th2 cytokines which include IL-2, IL-4, IL-6, IL-10, INF-γ and TNF-α in pneumonia caused by HMPV. METHODS: A retrospective study was performed among 59 pneumonia pediatric patients with HMPV infection and 33 healthy children as the control cohort, which was detected by the immunofluorescence assay, and the Th1/Th2 cytokines were measured by flow cytometry. 131 children infected with Influenza virus A (IVA) and 41 children infected with influenza virus B (IVB) were detected by RT-PCR assay in throat swabs. RESULTS: When compared with the healthy children, children who were infected with HMPV pneumonia had a significantly lower level of IL-2 (p < 0.001) and higher levels of IL-4 (p < 0.001), IL-6 (p = 0.001), IL-10 (p < 0.001), and IFN-γ (p < 0.001). Compared with patients diagnosed with IVA or IVB infection, HMPV-positive patients had significantly higher levels of IL-4 (p < 0.001 and < 0.001), IFN-γ (p < 0.001 and < 0.001), and TNF-α (p < 0.001 and 0.016). Moreover, compared with IVA patients, HMPV-positive patients had a significantly lower level of IL-6 (p = 0.033). Finally, when comparing cytokine levels among the patients with HMPV pneumonia, IL-6 and TNF-α levels were found to be significantly higher in the severe group than the mild group (p = 0.027 and 0.049). The IL-6 and TNF-α were used to differentiate between mild symptoms and severe symptoms in children diagnosed with HMPV pneumonia with an AUC of 0.678 (95% CI 0.526-0.829) and 0.658 (95% CI 0.506-0.809), respectively. CONCLUSION: Our study indicated that difference in cytokine trends depending on the virus species. The levels of IL-4, TNF-α and IFN-γ were significantly distinguished in children infected with HMPV versus IVA and IVB. IL-6 and TNF-α may be helpful in assessing the severity and prognosis of HMPV infection.

SSThe coexistence and diversity of Candidatus methylomirabilis oxyfera-like and anammox bacteria in sediments of an urban eutrophic lake / SLa coexistencia y diversidad de bacterias Candidatus methylomirabilis oxyfera y anammox en sedimentos de un lago urbano eutrófico

Tangxun Lake is the largest urban lake in China, which is polluted by multiple wastewaters, and now is severely eutrophic. We detected diversity, abundance, and the coexistence of Candidatus Methylomirabilis oxyfera-like and anammox bacteria in different horizontal and vertical directions of the lake sediments through qPCR and clone library. Phylogenetic tree analysis showed that the Ca. Methylomirabilis oxyfera-like and anammox bacteria exhibited high diversity, and they belonged to group B—E and Ca. Brocadia genus, respectively. These two bacteria displayed higher diversity in polluted area than in other areas. Furthermore, they had great spatial variation of abundance both horizontally and vertically. The abundance of anammox bacteria was significantly higher than that of Ca. Methylomirabilis oxyfera-like bacteria. The stronger the human interference were, the higher abundances these two bacteria exhibited horizontally, whereas both their abundances and the ratio of anammox to Ca. Methylomirabilis oxyfera-like bacteria decreased with the increasing depth. Redundancy analysis indicated that nitrate was the most influential environmental factor to the abundance of these two bacteria. Ammonia, nitrite, total nitrogen, and organic matters were in positive correlation with the abundance of these two bacteria. Nitrate was slightly negatively correlated with the abundance of Ca. Methylomirabilis oxyfera-like bacteria, while it was positively correlated with that of anammox bacteria. Our results provided an insight into the effects of environmental factors such as ammonia, nitrite, and nitrate on the diversity and abundances of these two bacteria and theoretical basis for restoration of water.(AU)