RESUMO
Variation in coat color among equids has attracted significant interest in genetics and breeding research. The range of colors is primarily determined by the type, concentration, and distribution of melanin pigments, with the balance between eumelanin and pheomelanin influenced by numerous genetic factors. Advances in genomic and sequencing technologies have enabled the identification of several candidate genes that influence coat color, thereby clarifying the genetic basis of these diverse phenotypes. In this review, we concisely categorize coat coloration in horses and donkeys, focusing on the biosynthesis and types of melanin involved in pigmentation. Moreover, we highlight the regulatory roles of some key candidate genes, such as MC1R, TYR, MITF, ASIP, and KIT, in coat color variation. Moreover, the review explores how coat color relates to selective breeding and specific equine diseases, offering valuable insights for developing breeding strategies that enhance both the esthetic and health aspects of equine species.
RESUMO
DNA methylation represents a predominant epigenetic modification with broad implications in various biological functions. Its role is particularly significant in the process of collagen deposition, a fundamental aspect of dermal development in donkeys. Despite its critical involvement, the mechanistic insights into how DNA methylation influences collagen deposition in donkey skin remain limited. In this study, we employed whole genome bisulfite sequencing (WGBS) and RNA sequencing (RNA-seq) to investigate the epigenetic landscape and gene expression profiles in the dorsal skin tissues of Dezhou donkeys across three developmental stages: embryonic (YD), juvenile (2-year-old, MD), and mature (8-year-old, OD). Our analysis identified numerous differentially methylated genes that play pivotal roles in skin collagen deposition and overall skin maturation, including but not limited to COL1A1, COL1A2, COL3A1, COL4A1, COL4A2, GLUL, SFRP2, FOSL1, SERPINE1, MMP1, MMP2, MMP9, and MMP13. Notably, we observed an inverse relationship between gene expression and DNA methylation proximal to transcription start sites (TSSs), whereas a direct correlation was detected in regions close to transcription termination sites (TTSs). Detailed bisulfite sequencing analyses of the COL1A1 promoter region revealed a low methylation status during the embryonic stage, correlating with elevated transcriptional activity and gene expression levels. Collectively, our findings elucidate key genetic markers associated with collagen deposition in the skin of Dezhou donkeys, underscoring the significant regulatory role of DNA methylation. This research work contributes to the foundational knowledge necessary for the genetic improvement and selective breeding of Dezhou donkeys, aiming to enhance skin quality attributes.
RESUMO
The primary focus of donkey hide gelatin processing lies in the dermal layer of donkey hide due to its abundant collagen content. However, the molecular mechanism involved in collagen organization and skin development in donkey skin tissue across various developmental stages remains incomplete. The current study aims to investigate the transcriptomic screening of lncRNAs and mRNA associated with skin development and collagen organization across different ages in Dezhou donkeys' skin. In the pursuit of this objective, we used nine skin tissue samples obtained from Dezhou donkeys at various ages including 8-month fetal stage, followed by 2 and 8 years. RNA-seq analysis was performed for the transcriptomic profiling of differentially expressed genes (DEGs) and lncRNAs associated with skin development in different age groups. Our investigation revealed the presence of 6,582, 6,455, and 405 differentially expressed genes and 654, 789, and 29 differentially expressed LncRNAs within the skin tissues of Dezhou donkeys when comparing young donkeys (YD) vs. middle-aged donkeys (MD), YD vs. old donkeys (OD), and MD vs. OD, respectively. Furthermore, we identified Collagen Type I Alpha 1 Chain (COL1A1), Collagen Type III Alpha 1 Chain (COL3A1), and Collagen Type VI Alpha 5 Chain (COL6A5) as key genes involved in collagen synthesis, with COL1A1 being subject to cis-regulation by several differentially expressed LncRNAs, including ENSEAST00005041187, ENSEAST00005038497, and MSTRG.17248.1, among others. Interestingly, collagen organizational and skin development linked pathways including Protein digestion and absorption, metabolic pathways, Phosphatidylinositol 3-Kinase-Protein Kinase B signaling pathway (PI3K-Akt signaling pathway), Extracellular Matrix-Receptor Interaction (ECM-receptor interaction), and Relaxin signaling were also reported across different age groups in Dezhou donkey skin. These findings enhance our comprehension of the molecular mechanisms underlying Dezhou donkey skin development and collagen biosynthesis and organization, thus furnishing a solid theoretical foundation for future research endeavors in this domain.
RESUMO
Introduction: The Dezhou donkey, a prominent Chinese breed, is known for its remarkable size, rapid growth, and resilience to tough feeding conditions, and disease resistance. These traits are crucial in meeting the growing demand for Ejiao and donkey meat. Yeast polysaccharide (YPS), a functional polysaccharide complex known for its immune-enhancing and growth-promoting properties in livestock and poultry, remains relatively understudied in donkeys. Objectives: This study aimed to investigate the impact of YPS supplementation on lactating and growing Dezhou donkey jennies and foals. Materials and methods: Twelve 45-day-old Dezhou donkey foals and their jennies, matched for body weight and age, were randomly allocated to two dietary groups: a control group receiving a basal diet and an experimental group receiving the basal diet supplemented with 10 g/pen of YPS. The experiment was conducted over a 23-day period, during which donkey foals and lactating jennies were co-housed. Results and discussion: The findings revealed that YPS supplementation had no adverse effects on milk production or composition in Dezhou donkey jennies but significantly increased feed intake. Additionally, YPS was associated with increased plasma glucose and creatinine concentrations in foals, while tending to decrease alkaline phosphatase, white blood cell count, red blood cell count, and hemoglobin levels (p < 0.10). Immune indices demonstrated that YPS supplementation elevated the levels of immunoglobulin A (IgA) and immunoglobulin G (IgG) in jennies (p < 0.05) and increased complement component C4 concentrations in foals (p < 0.05). Moreover, YPS positively influenced the fecal microbiome, promoting the abundance of beneficial microorganisms such as Lactobacillus and Prevotella in donkey foals and Terriporobacter and Cellulosilyticum in jennies, all of which contribute to enhanced feed digestion. Additionally, YPS induced alterations in the plasma metabolome for both jennies and foals, with a predominant presence of lipids and lipid-like molecules. Notably, YPS increased the concentrations of specific lipid metabolites, including 13,14-Dihydro PGF2a, 2-Isopropylmalic acid, 2,3-Dinor-TXB2, Triterpenoids, Taurocholic acid, and 3b-Allotetrahydrocortisol, all of which are associated with improved animal growth. Conclusion: In conclusion, this study suggests that dietary supplementation of YPS enhances feed intake, boosts immunity by increasing immunoglobulin levels, stimulates the growth-promoting gut microbiota (Lactobacillus and Prevotella), and exerts no adverse effects on the metabolism of both Dezhou donkey jennies and foals.
RESUMO
For dairy cattle to perform well throughout and following lactations, precise dietary control during the periparturient phase is crucial. The primary issues experienced by periparturient dairy cows include issues like decreased dry matter intake (DMI), a negative energy balance, higher levels of non-esterified fatty acids (NEFA), and the ensuing inferior milk output. Dairy cattle have always been fed a diet high in crude protein (CP) to produce the most milk possible. Despite the vital function that dairy cows play in the conversion of dietary CP into milk, a sizeable percentage of nitrogen is inevitably expelled, which raises serious environmental concerns. To reduce nitrogen emissions and their production, lactating dairy cows must receive less CP supplementation. Supplementing dairy cattle with rumen-protected methionine (RPM) and choline (RPC) has proven to be a successful method for improving their ability to use nitrogen, regulate their metabolism, and produce milk. The detrimental effects of low dietary protein consumption on the milk yield, protein yield, and dry matter intake may be mitigated by these nutritional treatments. In metabolic activities like the synthesis of sulfur-containing amino acids and methylation reactions, RPM and RPC are crucial players. Methionine, a limiting amino acid, affects the production of milk protein and the success of lactation in general. According to the existing data in the literature, methionine supplementation has a favorable impact on the pathways that produce milk. Similarly, choline is essential for DNA methylation, cell membrane stability, and lipid metabolism. Furthermore, RPC supplementation during the transition phase improves dry matter intake, postpartum milk yield, and fat-corrected milk (FCM) production. This review provides comprehensive insights into the roles of RPM and RPC in optimizing nitrogen utilization, metabolism, and enhancing milk production performance in periparturient dairy cattle, offering valuable strategies for sustainable dairy farming practices.
RESUMO
Recently, the optoelectronic memory is capturing growing attention due to its integrated function of sense and memory as well as multilevel storage ability. Although tens of states have been reported in literature, there are still three obvious deficiencies in most of the optoelectronic memories: large programming voltage (>20 V), high optical power density (>1 mW cm-2), and poor compatibility originating from the over-reliance on channel materials. Here, we firstly propose an optoelectronic memory based on a new photosensitive dielectric (PSD) architecture. Data writing and erasing are realized by using an optical pulse to switch on the PSD. The unique design enables the memory to work with a programming voltage and optical power density as low as 4 V and 160 µW cm-2, respectively. Meanwhile, this device may be extended to different kinds of transistors for specific applications. Our discovery offers a brand-new direction for non-volatile optoelectronic memories with low energy consumption.
RESUMO
BACKGROUND: At present, donkey meat in the market shows an imbalance between supply and demand, and there is an urgent need to cultivate a meat-type Dezhou donkey breed. On the one hand, it can improve the imbalance in the market, and on the other hand, it can promote the rapid development of the donkey industry. This study aimed to reveal significant genetic variation in the NK1 homeobox 2 gene (NKX1-2) of Dezhou donkeys and investigate the association between genotype and body size in Dezhou donkeys. RESULTS: In this study, a SNP (g.54704925 A > G) was identified at the exon4 by high-depth resequencing of the Dezhou donkey NKX1-2 gene. The AA genotype is the dominant genotype. The g.54704925 A > G site was significantly associated with body length, thoracic girth, and hide weight (P < 0.05), while it was highly significantly associated with body height and carcass weight (P < 0.01) in Dezhou donkeys. CONCLUSION: Overall, the results of this study showed that the NKX1-2 gene could be a candidate gene for breeding meat-type Dezhou donkeys, and the g.54704925 A > G locus could be used as a marker locus for selection and breeding.
Assuntos
Equidae , Animais , Tamanho Corporal/genética , Equidae/genética , Genótipo , Fenótipo , Análise de Sequência de DNA , Polimorfismo de Nucleotídeo ÚnicoRESUMO
Nanoscale zero-valent iron (nZVI) has a high removal affinity toward arsenic (As). However, the agglomeration of nZVI reduces the removal efficiency of As and, thus, limit its application. In this study, we report an environmentally friendly novel composite of Chlorella vulgaris-supported nanoscale zero-valent iron (abbreviated as CV-nZVI) that exhibits a fast and efficient removal of As(III) from As-contaminated water. Scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS), X-ray diffractometry (XRD), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS) were used to characterize and analyze the CV-nZVI. These results indicated that the stabilization effect of C. vulgaris reduced the nZVI agglomeration and enhanced the reactivity of nZVI. The experiments showed a removal efficiency of 99.11% for As(III) at an optimum pH of 7.0. The adsorption kinetics and isotherms followed the pseudo-second-order kinetic model and Langmuir adsorption isotherm with the superior maximum adsorption capacities of 34.11 mg/g for As(III). The FTIR showed that the As(III) was adsorbed on the CV-nZVI surface by complexation reaction, and XPS indicated that oxidation reaction was also involved. After five reuse cycles, the removal efficiency of As(III) by CV-nZVI was 32.93%, suggesting that the CV-nZVI had some reusability and regeneration. Overall, this work provides a practical and highly efficient approach for As remediation in As-contaminated water, and simultaneously resolves the agglomeration problems of nZVI nanoparticles.
Assuntos
Arsênio , Chlorella vulgaris , Poluentes Químicos da Água , Poluentes Químicos da Água/análise , Ferro/química , Adsorção , ÁguaRESUMO
The lipid molecules and volatile organic compounds (VOCs) in milk are heavily influenced by diet. However, little is known about how roughage affects the lipid and VOC contents of donkey milk. Accordingly, in the present study, donkeys were fed corn straw (G1 group), wheat hulls (G2 group), or wheat straw (G3 group), and the lipid and VOC profiles of their milk were determined using LC-MS and GC-MS. Of the 1842 lipids identified in donkey milk, 153 were found to be differential, including glycerolipids, glycerophospholipids, and sphingolipids. The G1 group showed a greater variety and content of triacyclglycerol species than the G2 and G3 groups. Of 45 VOCs, 31 were identified as differential, including nitrogen compounds, esters, and alcohols. These VOCs were significantly increased in the G2 and G3 groups, with the greatest difference being between the G1 and G2 groups. Thus, our study demonstrates that dietary roughage changes the lipid and VOC profiles of donkey milk.
RESUMO
X-ray detectors must be operated at minimal doses to reduce radiation health risks during X-ray security examination or medical inspection, therefore requiring high sensitivity and low detection limits. Although organolead trihalide perovskites have rapidly emerged as promising candidates for X-ray detection due to their low cost and remarkable performance, these materials threaten the safety of the human body and environment due to the presence of lead. Here we present the realization of highly sensitive X-ray detectors based on an environmentally friendly solution-grown thick BiI/BiI3/BiI (BixIy) van der Waals heterostructure. The devices exhibit anisotropic X-ray detection response with a sensitivity up to 4.3 × 104 µC Gy-1 cm-2 and a detection limit as low as 34 nGy s-1. At the same time, our BixIy detectors demonstrate high environmental and hard radiation stabilities. Our work motivates the search for new van der Waals heterostructure classes to realize high-performance X-ray detectors and other optoelectronic devices without employing toxic elements.
RESUMO
Thermal transport properties of amorphous materials are crucial for their emerging applications in energy and electronic devices. However, understanding and controlling thermal transport in disordered materials remains an outstanding challenge, owing to the intrinsic limitations of computational techniques and the lack of physically intuitive descriptors for complex atomistic structures. Here, it is shown how combining machine-learning-based models and experimental observations can help to accurately describe realistic structures, thermal transport properties, and structure-property maps for disordered materials, which is illustrated by a practical application on gallium oxide. First, the experimental evidence is reported to demonstrate that machine-learning interatomic potentials, generated in a self-guided fashion with minimum quantum-mechanical computations, enable the accurate modeling of amorphous gallium oxide and its thermal transport properties. The atomistic simulations then reveal the microscopic changes in the short-range and medium-range order with density and elucidate how these changes can reduce localization modes and enhance coherences' contribution to heat transport. Finally, a physics-inspired structural descriptor for disordered phases is proposed, with which the underlying relationship between structures and thermal conductivities is predicted in a linear form. This work may shed light on the future accelerated exploration of thermal transport properties and mechanisms in disordered functional materials.
RESUMO
Mastitis, the inflammatory condition of mammary glands, has been closely associated with immune suppression and imbalances between antioxidants and free radicals in cattle. During the periparturient period, dairy cows experience negative energy balance (NEB) due to metabolic stress, leading to elevated oxidative stress and compromised immunity. The resulting abnormal regulation of reactive oxygen species (ROS) and reactive nitrogen species (RNS), along with increased non-esterified fatty acids (NEFA) and ß-hydroxybutyric acid (BHBA) are the key factors associated with suppressed immunity thereby increases susceptibility of dairy cattle to infections, including mastitis. Metabolic diseases such as ketosis and hypocalcemia indirectly contribute to mastitis vulnerability, exacerbated by compromised immune function and exposure to physical injuries. Oxidative stress, arising from disrupted balance between ROS generation and antioxidant availability during pregnancy and calving, further contributes to mastitis susceptibility. Metabolic stress, marked by excessive lipid mobilization, exacerbates immune depression and oxidative stress. These factors collectively compromise animal health, productive efficiency, and udder health during periparturient phases. Numerous studies have investigated nutrition-based strategies to counter these challenges. Specifically, amino acids, trace minerals, and vitamins have emerged as crucial contributors to udder health. This review comprehensively examines their roles in promoting udder health during the periparturient phase. Trace minerals like copper, selenium, and calcium, as well as vitamins; have demonstrated significant impacts on immune regulation and antioxidant defense. Vitamin B12 and vitamin E have shown promise in improving metabolic function and reducing oxidative stress followed by enhanced immunity. Additionally, amino acids play a pivotal role in maintaining cellular oxidative balance through their involvement in vital biosynthesis pathways. In conclusion, addressing periparturient mastitis requires a holistic understanding of the interplay between metabolic stress, immune regulation, and oxidative balance. The supplementation of essential amino acids, trace minerals, and vitamins emerges as a promising avenue to enhance udder health and overall productivity during this critical phase. This comprehensive review underscores the potential of nutritional interventions in mitigating periparturient bovine mastitis and lays the foundation for future research in this domain.
Assuntos
Mastite , Oligoelementos , Feminino , Gravidez , Bovinos , Animais , Humanos , Vitaminas , Antioxidantes , Aminoácidos , Espécies Reativas de Oxigênio , Rúmen , Vitamina A , Vitamina K , Anti-InflamatóriosRESUMO
An increase in the number of vertebrae can significantly affect the meat production performance of livestock, thus increasing carcass weight, which is of great importance for livestock production. The homeobox gene C8 (HOXC8) has been identified as an essential candidate gene for regulating vertebral development. However, it has not been researched on the Dezhou donkey. This study aimed to verify the Dezhou donkey HOXC8 gene's polymorphisms and assess their effects on multiple vertebral numbers and carcass weight. In this study, the entire HOXC8 gene of the Dezhou donkey was sequenced, SNPs at the whole gene level were identified, and typing was accomplished utilizing a targeted sequencing genotype detection technique (GBTS). Then, a general linear model was used to perform an association study of HOXC8 gene polymorphism loci, multiple vertebral numbers, and carcass weight for screening candidate markers that can be used for molecular breeding of Dezhou donkeys. These findings revealed that HOXC8 included 12 SNPs, all unique mutant loci. The HOXC8 g.15179224C>T was significantly negatively associated with carcass weight (CW) and lumbar vertebrae length (LL) (p < 0.05). The g.15179674G>A locus was shown to be significantly positively associated with the number of lumbar vertebrae (LN) (p < 0.05). The phylogenetic tree constructed for the Dezhou donkey HOXC8 gene and seven other species revealed that the HOXC8 gene was highly conserved during animal evolution but differed markedly among distantly related animals. The results suggest that HOXC8 is a vital gene affecting multiple vertebral numbers and carcass weight in Dezhou donkeys, and the two loci g.15179224C>T and g.15179674G>A may be potential genetic markers for screening and breeding of new strains of high-quality and high-yielding Dezhou donkeys.
Assuntos
Equidae , Genes Homeobox , Animais , Equidae/genética , Filogenia , Polimorfismo de Nucleotídeo Único/genética , Vértebras LombaresRESUMO
Several studies have shown the association between the ligand-dependent nuclear receptor compression-like protein (LCORL) gene and body size in horses, pigs and donkeys. Based on previous studies, the LCORL gene was hypothesized to be associated with growth traits and hide weight in Dezhou donkeys. In this study, we aimed to reveal the variation of the LCORL gene in the Dezhou donkey and explore whether the gene is associated with hide weight and body size. In this study, genetic polymorphisms in the LCORL gene of the Dezhou donkey were studied using targeted sequencing technology, and single nucleotide polymorphisms (SNPs) of the LCORL gene were analyzed for association with hide weight and body size in Dezhou donkeys. The results showed that there was an SNP locus situated in intron 1 of the LCORL gene. Association analysis revealed that individuals with the GG genotype had significantly higher body height, body length, chest circumference and hide weight than those with the AA genotype (p < 0.05). Therefore, the g.112558859 A > G locus can be used as a potential candidate marker affecting body size and hide weight. This study provides the foundation for breeding high-quality donkeys with high hide yield.
RESUMO
Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterized by recurrent arteriovenous thrombosis and/or morbid pregnancy. Valve involvement is the most common cardiac manifestation of APS, with lesions characterized by valve thickening and vegetations known as Libman-Sacks endocarditis (LSE). This report discussed a rare case of a 26-year-old young woman diagnosed with primary APS with multiple cerebral infarctions and right middle cerebral artery occlusion that occured 3 years ago. During the investigation, transthoracic echocardiography (TTE) revealed vegetations on both leaflets of the mitral valve with mild to moderate mitral regurgitation. One year following corticosteroid and anticoagulant treatment, mitral valve fibrosis and moderate to severe regurgitation were noted, after which mitral mechanical valve replacement was finally performed. Accordingly, this report suggests that LSE occurrence should be alerted during the examination of APS patients especially in those with cerebrovascular disease. Furthermore, establishing an early diagnosis and conducting close follow-ups are necessary for its timely intervention and treatment.
RESUMO
BACKGROUND: Preterm birth is serious public health worldwide, and early prediction of preterm birth in pregnant women may provide assistance for timely intervention and reduction of preterm birth. This study aimed to develop a preterm birth prediction model that is readily available and convenient for clinical application. METHODS: Data used in this case-control study were extracted from the National Vital Statistics System (NVSS) database between 2018 and 2019. Univariate and multivariate logistic regression analyses were utilized to find factors associated with preterm birth. Odds ratio (OR) and 95% confidence interval (CI) were used as effect measures. The area under the curve (AUC), accuracy, sensitivity, and specificity were utilized as model performance evaluation metrics. RESULTS: Data from 3,006,989 pregnant women in 2019 and 3,039,922 pregnant women in 2018 were used for the model establishment and external validation, respectively. Of these 3,006,989 pregnant women, 324,700 (10.8%) had a preterm birth. Higher education level of pregnant women [bachelor (OR = 0.82; 95%CI, 0.81-0.84); master or above (OR = 0.82; 95%CI, 0.81-0.83)], pre-pregnancy overweight (OR = 0.96; 95%CI, 0.95-0.98) and obesity (OR = 0.94; 95%CI, 0.93-0.96), and prenatal care (OR = 0.48; 95%CI, 0.47-0.50) were associated with a reduced risk of preterm birth, while age ≥ 35 years (OR = 1.27; 95%CI, 1.26-1.29), black race (OR = 1.26; 95%CI, 1.23-1.29), pre-pregnancy underweight (OR = 1.26; 95%CI, 1.22-1.30), pregnancy smoking (OR = 1.27; 95%CI, 1.24-1.30), pre-pregnancy diabetes (OR = 2.08; 95%CI, 1.99-2.16), pre-pregnancy hypertension (OR = 2.22; 95%CI, 2.16-2.29), previous preterm birth (OR = 2.95; 95%CI, 2.88-3.01), and plurality (OR = 12.99; 95%CI, 12.73-13.24) were related to an increased risk of preterm birth. The AUC and accuracy of the prediction model in the testing set were 0.688 (95%CI, 0.686-0.689) and 0.762 (95%CI, 0.762-0.763), respectively. In addition, a nomogram based on information on pregnant women and their spouses was established to predict the risk of preterm birth in pregnant women. CONCLUSIONS: The nomogram for predicting the risk of preterm birth in pregnant women had a good performance and the relevant predictors are readily available clinically, which may provide a simple tool for the prediction of preterm birth.
Assuntos
Nascimento Prematuro , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Recém-Nascido , Razão de Chances , Gravidez , Nascimento Prematuro/epidemiologia , Nascimento Prematuro/etiologia , Fatores de Risco , Magreza/complicações , Estados Unidos/epidemiologiaAssuntos
Síndrome Antifosfolipídica , Endocardite Bacteriana , Endocardite , Lúpus Eritematoso Sistêmico , Humanos , Síndrome Antifosfolipídica/complicações , Endocardite/complicações , Endocardite/diagnóstico por imagem , Endocardite Bacteriana/complicações , Endocardite Bacteriana/diagnóstico por imagem , Lúpus Eritematoso Sistêmico/complicaçõesRESUMO
Cephalosporin antibiotics, a group of widely prescribed antibiotics, are frequently detected in wastewater effluent and in the natural aquatic environment. Materials have been sought to effectively degrade the antibiotics. In this study, a novel high-iron clay was prepared with potassium ferrate and montmorillonite via a strong alkaline in situ synthesis method. Degradation of cefazolin sodium (CFZ) by this novel Fe (VI)-clay was investigated. The optimal conditions for the degradation of CFZ were determined using a single factor experiment and response surface optimization method. We found that 89.84% removal efficiency was obtained in 137 min when pH value was 5.16 and Fe (VI)-clay dosage was 0.79 g. The CFZ degradation mechanism was studied by computations on the Frontier Electron Density (FED) in combination with spectroscopic and mass spectroscopic analysis. The spectroscopic characteristics of the products at different stages showed that the oxidation decomposition reaction occurred during the degradation of CFZ by Fe (VI)-clay. Furthermore, FED calculation combined with GC-MS results showed that the degradation pathways of CFZ by the Fe (VI)-clay was mainly the cleavage of ß-lactam, thiadiazole, tetrazole, and dihydrothiazine rings.
Assuntos
Poluentes Químicos da Água , Purificação da Água , Antibacterianos/química , Cefazolina , Argila , Ferro/química , Cinética , Oxirredução , Poluentes Químicos da Água/análise , Purificação da Água/métodosRESUMO
The rapid start-up and operating characteristics of simultaneous partial nitrification, anammox, and denitrification (SNAD) process was investigated using synthetic wastewater with a low C/N ratio (COD: NH4+-N = 200 mg/L: 200 mg/L) in a novel upflow microaerobic membrane bioreactor (UMMBR). The average removal efficiencies of COD, NH4+-N, and TN in the stable phase were 89%, 96%, and 86%, respectively. Carmine granule, which coexisted with sludge floc, appeared on day 83. The high sludge concentration (12.9-17.2 g/L) and the upflow mode of the UMMBR could establish some anaerobicregions for anammox process. The anammox bacteria and short-cut denitrification (NO2-âN2) bacteria with activities of 4.46 mg NH4+-N/gVSS·h and 2.57 mg NO2--N/gVSS·h contributed TN removal of 39% and 61% on day 129, respectively. High-throughput sequencing analysis revealed that the ammonia-oxidizing archaea (AOA, 49.45% in granule and 17.05% in sludge floc) and ammonia-oxidizing bacterial (AOB, 1.30% in sludge floc) dominated the nitrifying microbial community. Candidatus Jettenia (47.14%) and Denitratisoma (10.92%) mainly existed in granule with positive correlations. Some heterotrophic bacteria (OLB13, SJA-15, 1-20, SBR1031, and SJA-28) in sludge floc benefited system stability and sludge activity and protected Candidatus Jettenia from adverse environments.
Assuntos
Nitrificação , Águas Residuárias , Amônia , Oxidação Anaeróbia da Amônia , Reatores Biológicos/microbiologia , Desnitrificação , Nitrogênio , Oxirredução , Esgotos/microbiologiaRESUMO
The effects of alkalinity addition with different strategies on the start-up, performance, and microbial community of completely autotrophic nitrogen removal over nitrite (CANON) were investigated over 450 days. In phase I, the alkalinity was increased gradually from 300 to 2,000 mg/L to obtain the optimal range. In phase II, the reactor was restarted to verify the appropriate alkalinity value of 1,600 mg/L. The fact that it only took 90 days (phase I: 170 days) to complete the start-up of CANON in phase II demonstrated that an alkalinity value of 1,600 mg/L was suitable when the influent NH4 + -N concentration was 200 mg/L (alkalinity/NH4 + -N = 8:1). The slope (k = 2.00) of NH4 + -N concentration decrease in phase II during the start-up process was significantly higher than that in phase I (k = 1.50). High removal efficiencies of NH4 + -N (98%) and TN (80%) were attained in both phases. Specific anaerobic ammonium oxidation (anammox) activity tests showed that the anammox activity of the two phases reached 3.31 and 5.31 mg TN/(g VSS·h), respectively. High-throughput sequencing analysis revealed that appropriate alkalinity could promote the enrichment of Candidatus Brocadia, C. Jettenia, and C. Kuenenia (total abundance of 31.96%) while effectively inhibiting Nitrospira (abundance of less than 0.50%). PRACTITIONER POINTS: An alkalinity/NH4 + -N ratio of 8 promoted the rapid start-up and stable performance of CANON. NH4 + -N and TN removal efficiencies of 98% and 80%, respectively, were obtained. High alkalinity promoted the enrichment of Candidatus Brocadia, Candidatus Jettenia, Candidatus Kuenenia and inhibited Nitrospira.