RESUMEN
Tetrabromobisphenol A (TBBPA), a widely used brominated flame retardant in electronics manufacturing, has caused global contamination due to improper e-waste disposal. Its persistence, bioaccumulation, and potential carcinogenicity drive studies of its transformation and underlying (a)biotic interactions. This study achieved an anaerobic enrichment culture capable of reductively dehalogenating TBBPA to the more bioavailable bisphenol A. 16S rRNA gene amplicon sequencing and quantitative PCR confirmed that successive dehalogenation of four bromide ions from TBBPA was coupled with the growth of both Dehalobacter sp. and Dehalococcoides sp. with growth yields of 5.0 ± 0.4 × 108 and 8.6 ± 4.6 × 108 cells per µmol Br- released (N = 3), respectively. TBBPA dehalogenation was facilitated by solid humin and reduced humin, which possessed the highest organic radical signal intensity and reducing groups -NH2, and maintained the highest dehalogenation rate and dehalogenator copies. Genome-centric metatranscriptomic analyses revealed upregulated putative TBBPA-dehalogenating rdhA (reductive dehalogenase) genes with humin amendment, cprA-like Dhb_rdhA1 gene in Dehalobacter species, and Dhc_rdhA1/Dhc_rdhA2 genes in Dehalococcoides species. The upregulated genes of lactate fermentation, de novo corrinoid biosynthesis, and extracellular electron transport in the humin amended treatment also stimulated TBBPA dehalogenation. This study provided a comprehensive understanding of humin-facilitated organohalide respiration.
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Sustancias Húmicas , Bifenilos Polibrominados , Anaerobiosis , ARN Ribosómico 16S/genética , Biodegradación AmbientalRESUMEN
Hypoxia-ischemia (HI) of the brain not only impairs neurodevelopment but also causes pineal gland dysfunction, which leads to circadian rhythm disruption. However, the underlying mechanism of circadian rhythm disruption associated with HI-induced pineal dysfunction remains unknown. The zinc finger protein repressor protein with a predicted molecular mass of 58 kDa (RP58) is involved in the development and differentiation of nerve cells. In this study, we established an HI model in neonatal rats to investigate the expression of RP58 and its role in pineal dysfunction and circadian rhythm disruption induced by HI. We demonstrated that RP58 was highly expressed in the pineal gland under normal conditions and significantly downregulated in the pineal gland and primary pinealocytes following HI. Knockdown of RP58 decreased the expression of enzymes in the melatonin (Mel) synthesis pathway (tryptophan hydroxylase 1 [TPH1], acetylserotonin O-methyltransferase [ASMT], and arylalkylamine N-acetyltransferase [AANAT]) and clock genes (circadian locomotor output cycles kaput [CLOCK] and brain and muscle ARNT-like 1 [BMAL1]), and it also reduced the production of Mel, caused pineal cell injury, and disrupted circadian rhythms in vivo and in vitro. Similarly, HI reduced the expression of Mel synthesis enzymes (TPH1, ASMT, and AANAT) and clock genes (CLOCK and BMAL1), and caused pineal injury and circadian rhythm disruption, which were exacerbated by RP58 knockdown. The detrimental effect of RP58 knockdown on pineal dysfunction and circadian rhythm disruption was reversed by the addition of exogenous Mel. Furthermore, exogenous Mel reversed HI-induced pineal dysfunction and circadian rhythm disruption, as reflected by improvements in Mel production, voluntary activity periods, and activity frequency, as well as a diminished decrease in the expression of Mel synthesis enzymes and clock genes. The present study suggests that RP58 is an endogenous source of protection against pineal dysfunction and circadian rhythm disruption after neonatal HI.
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Melatonina , Glándula Pineal , Ratas , Animales , Melatonina/metabolismo , Animales Recién Nacidos , Factores de Transcripción ARNTL/metabolismo , ARN Mensajero/metabolismo , Ritmo Circadiano/fisiología , Glándula Pineal/metabolismo , Hipoxia/metabolismo , Isquemia/metabolismo , N-Acetiltransferasa de Arilalquilamina/genética , N-Acetiltransferasa de Arilalquilamina/metabolismoRESUMEN
Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile, TePN) is one of the most widely used fungicides all over the world. Its major environmental transformation product 4-hydroxy-chlorothalonil (4-hydroxy-2,5,6-trichloroisophthalonitrile, 4-OH-TPN) is more persistent, mobile, and toxic and is frequently detected at a higher concentration in various habitats compared to its parent compound TePN. Further microbial transformation of 4-OH-TPN has never been reported. In this study, we demonstrated that 4-OH-TPN underwent complete microbial reductive dehalogenation to 4-hydroxy-isophthalonitrile via 4-hydroxy-dichloroisophthalonitrile and 4-hydroxy-monochloroisophthalonitrile. 16S rRNA gene amplicon sequencing demonstrated that Dehalogenimonas species was enriched from 6% to 17-22% after reductive dechlorination of 77.24 µmol of 4-OH-TPN. Meanwhile, Dehalogenimonas copies increased by one order of magnitude and obtained a yield of 1.78 ± 1.47 × 108 cells per µmol Cl- released (N = 6), indicating that 4-OH-TPN served as the terminal electron acceptor for organohalide respiration of Dehalogenimonas species. A draft genome of Dehalogenimonas species was assembled through metagenomic sequencing, which harbors 30 putative reductive dehalogenase genes. Syntrophobacter, Acetobacterium, and Methanosarcina spp. were found to be the major non-dechlorinating populations in the microbial community, who might play important roles in the reductive dechlorination of 4-OH-TPN by the Dehalogenimonas species. This study first reports that Dehalogenimonas sp. can also respire on the seemingly dead-end product of TePN, paving the way to complete biotransformation of the widely present TePN and broadening the substrate spectrum of Dehalogenimonas sp. to polychlorinated hydroxy-benzonitrile.
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Chloroflexi , Biodegradación Ambiental , Biotransformación , Chloroflexi/metabolismo , Nitrilos , ARN Ribosómico 16S/genéticaRESUMEN
BACKGROUND: This study was designed to explore the epidemiological and clinical profiles of respiratory syncytial virus (RSV) infection in neonates from the Suzhou area of China, taking into consideration how climate factors influence disease. METHODS: From 2010 to 2014, nasopharyngeal aspirates (NPA) collected from hospitalized neonates with lower respiratory tract infections (LRIs) were screened for seven common respiratory viruses including RSV by direct immunofluorescence assay. Human bocavirus, human metapneumovirus, and mycoplasma pneumoniae were detected by polymerase chain reaction. RESULTS: Of the 1803 hospitalized neonates analyzed, 20.74 % were found to be infected with RSV. Interestingly, 30 subjects were identified as being coinfected with other viruses. The rate of RSV infection was highestduring thewinter and early spring seasons; however, infection was negatively associated with monthly mean temperature (rs = -0.821, P < 0.0001), total rainfall (rs = -0.406, P = 0.002), and sum of sunshine (rs = -0.386, P = 0.001). Monthly mean temperature was the only independent factor associated with RSV activity, as determined using multivariate regression analysis. Compared with non-RSV neonates, neonates with RSV infection presented more frequently with tachypnea,moist rales, and abnormal chest X-rays requiring supplemental oxygen and extended hospitalization postpartum. Neonatal admittance into the NICU was determined based on prematurity and coinfection with other viruses; two independent risk factors for RSV disease, as determined by multivariate logistic analysis. CONCLUSIONS: Important as a major cause of LRIs in hospitalized neonate, we found that the subtropical climate of the Suzhou area was associated with RSV activity. The identified risk factors ofsevere disease in neonates with RSV infection should be taken into consideration when implementing disease health interventions.
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Infecciones por Virus Sincitial Respiratorio/diagnóstico , Infecciones del Sistema Respiratorio/diagnóstico , China/epidemiología , Coinfección/complicaciones , Coinfección/diagnóstico , Demografía , Femenino , Hospitalización , Humanos , Incidencia , Recién Nacido , Recien Nacido Prematuro , Unidades de Cuidado Intensivo Neonatal , Tiempo de Internación , Masculino , Nasofaringe/virología , Infecciones por Virus Sincitial Respiratorio/epidemiología , Infecciones por Virus Sincitial Respiratorio/virología , Virus Sincitial Respiratorio Humano/aislamiento & purificación , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/virología , Factores de Riesgo , Estaciones del AñoRESUMEN
BACKGROUND: Severe neonatal hyperbilirubinemia can cause hearing impairment. Bilirubin can be deposited in nerve cells, and the brainstem and the 8th nerve are especially sensitive to bilirubin toxicity. Abnormal changes in brainstem auditory evoked potential (BAEP) can be observed, and the BAEP test measures a nerve potential induced by short, high-frequency sound stimulation; thus, it is able to detect damage to the auditory conduction pathway in children. We aimed to identify relationships between clinical features and BAEP abnormalities in children with hyperbilirubinemia and to assess the predictive power of these risk factors for bilirubin-induced neurological damage. METHODS: Children with hyperbilirubinemia were evaluated with BAEP and retrospectively enrolled in the study between January 2012 and December 2018. Multivariate logistic regression was performed to identify independent predictors of BAEP abnormalities. RESULTS: Of the 561 children with hyperbilirubinemia enrolled, the BAEP anomaly group accounted for 198 (35.3%) cases. Except for body weight, there were no significant differences in the general data between the two groups with hyperbilirubinemia (p > 0.05). Univariate analysis showed that prematurity, abnormal umbilical cord, and gestational diabetes during pregnancy were significantly correlated with abnormal BAEP. Multivariate logistic regression analysis identified prematurity (p = 0.001), gestational diabetes (p = 0.03), Premature rupture of membranes (p = 0.013), total serum bilirubin (TSB), bilirubin/albumin (B/A) as independent risk factors for BAEP abnormalities. The prediction accuracy of TSB (Area Under Curve (AUC) = 0.557) and B/A (AUC = 0.566) was low, indicating that abnormal BAEP should be detected by multiple factors. CONCLUSIONS: Multivariate detection is beneficial for predicting the occurrence of auditory nerve injury in patients with hyperbilirubinemia.
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Potenciales Evocados Auditivos del Tronco Encefálico , Hiperbilirrubinemia Neonatal , Humanos , Femenino , Recién Nacido , Masculino , Estudios Retrospectivos , Hiperbilirrubinemia Neonatal/sangre , Hiperbilirrubinemia Neonatal/fisiopatología , Hiperbilirrubinemia Neonatal/complicaciones , Hiperbilirrubinemia Neonatal/diagnóstico , Factores de Riesgo , Bilirrubina/sangre , Embarazo , Diabetes Gestacional/fisiopatología , Diabetes Gestacional/sangreRESUMEN
Trace iron ions (Fe(III)) are commonly found in water and wastewater, where free chlorine is very likely to coexist with Fe(III) affecting the disinfectant's stability and N-DBPs' fate during UV/chlorine disinfection, and yet current understanding of these mechanisms is limited. This study investigates the effects of Fe(III) on the formation and toxicity alteration of halonitromethanes (HNMs), dichloroacetonitrile (DCAN), and dichloroacetamide (DCAcAm) from polyethyleneimine (PEI) during UV/chlorine disinfection. Results reveal that the maxima concentrations of HNMs, DCAN, and DCAcAm during UV/chlorine disinfection with additional Fe(III) were 1.39, 1.38, and 1.29 times higher than those without additional Fe(III), instead of being similar to those of Fe(III) inhibited the formation of HNMs, DCAN and DCAcAm during chlorination disinfection. Meanwhile, higher Fe(III) concentration, acidic pH, and higher chlorine dose were more favorable for forming HNMs, DCAN, and DCAcAm during UV/chlorine disinfection, which were highly dependent on the involvement of HO· and Cl·. Fe(III) in the aquatic environment partially hydrolyzed to the photoactive Fe(III)hydroxyl complexes Fe(OH)2+ and [Fe(H2O)6]3+, which undergone UV photoactivation and coupling reactions with HOCl to achieve effective Fe(III)/Fe(II) interconversion, a process that facilitated the sustainable production of HO·. Extensive product analysis and comparison verified that the HO· production enhanced by the Fe(III)/Fe(II) internal cycle played a primary role in increasing HNMs, DCAN, and DCAcAm productions during UV/chlorine disinfection. Note that the incorporation of Fe(III) increased the cytotoxicity and genotoxicity of HNMs, DCAN, and DCAcAm formed during UV/chlorine disinfection, and yet Fe(III) did not have a significant effect on the acute toxicity of water samples before, during, and after UV/chlorine disinfection. The new findings broaden the knowledge of Fe(III) affecting HNMs, DCAN, and DCAcAm formation and toxicity alteration during UV/chlorine disinfection.
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Desinfección , Desinfección/métodos , Rayos Ultravioleta , Cloro/química , Polietileneimina/química , Acetonitrilos/química , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/toxicidad , Hierro/química , Purificación del Agua/métodos , Acetamidas/química , Acetamidas/toxicidad , Desinfectantes/químicaRESUMEN
Tetrabromobisphenol A (TBBPA), a common brominated flame retardant and a notorious pollutant in anaerobic environments, resists aerobic degradation but can undergo reductive dehalogenation to produce bisphenol A (BPA), an endocrine disruptor. Conversely, BPA is resistant to anaerobic biodegradation but susceptible to aerobic degradation. Microbial degradation of TBBPA via anoxic/oxic processes is scarcely documented. We established an anaerobic microcosm for TBBPA dehalogenation to BPA facilitated by humin. Dehalobacter species increased with a growth yield of 1.5 × 108 cells per µmol Br- released, suggesting their role in TBBPA dehalogenation. We innovatively achieved complete and sustainable biodegradation of TBBPA in sand/soil columns columns, synergizing TBBPA reductive dehalogenation by anaerobic functional microbiota and BPA aerobic oxidation by Sphingomonas sp. strain TTNP3. Over 42 days, 95.11 % of the injected TBBPA in three batches was debrominated to BPA. Following injection of strain TTNP3 cells, 85.57 % of BPA was aerobically degraded. Aerobic BPA degradation column experiments also indicated that aeration and cell colonization significantly increased degradation rates. This treatment strategy provides valuable technical insights for complete TBBPA biodegradation and analogous contaminants.
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Biodegradación Ambiental , Retardadores de Llama , Oxidación-Reducción , Fenoles , Bifenilos Polibrominados , Bifenilos Polibrominados/metabolismo , Bifenilos Polibrominados/química , Anaerobiosis , Aerobiosis , Fenoles/metabolismo , Retardadores de Llama/metabolismo , Compuestos de Bencidrilo/metabolismo , Sphingomonas/metabolismo , Halogenación , Contaminantes del Suelo/metabolismoRESUMEN
Tetrachloroethylene ï¼PCEï¼ and trichloroethylene ï¼TCEï¼ are typical volatile halogenated organic compounds in groundwater that pose serious threats to the ecological environment and human health. To obtain an anaerobic microbial consortium capable of efficiently dechlorinating PCE and TCE to a non-toxic end product and to explore its potential in treating contaminated groundwaterï¼ an anaerobic microbial consortium W-1 that completely dechlorinated PCE and TCE to ethylene was obtained by repeatedly feeding PCE or TCE into the contaminated groundwater collected from an industrial site. The dechlorination rates of PCE and TCE were ï¼120.1 ±4.9ï¼ µmol·ï¼L·dï¼-1 and ï¼172.4 ±21.8ï¼ µmol·ï¼L·dï¼-1 in W-1ï¼ respectively. 16S rRNA gene amplicon sequencing and quantitative PCR ï¼qPCRï¼ showed that the relative abundance of Dehalobacter increased from 1.9% to 57.1%ï¼ with the gene copy number increasing by 1.7×107 copies per 1 µmol Cl- released when 98.3 µmol of PCE was dechlorinated to cis-1ï¼2-dichloroethylene ï¼cis-1ï¼2-DCEï¼. The relative abundance of Dehalococcoides increased from 1.1% to 53.8% when cis-1ï¼2-DCE was reductively dechlorinated to ethylene. The growth yield of Dehalococcoides gene copy number increased by 1.7×108 copies per 1 µmol Cl- released for the complete reductive dechlorination of PCE to ethylene. The results indicated that Dehalobacter and Dehalococcoides cooperated to completely detoxify PCE. When TCE was used as the only electron acceptorï¼ the relative abundance of Dehalococcoides increased from ï¼29.1 ±2.4ï¼% to ï¼7.7 ±0.2ï¼%ï¼ and gene copy number increased by ï¼1.9 ±0.4ï¼×108 copies per 1 µmol Cl- releasedï¼ after dechlorinating 222.8 µmol of TCE to ethylene. The 16S rRNA gene sequence of Dehalococcoides LWT1ï¼ the main functional dehalogenating bacterium in enrichment culture W-1ï¼ was obtained using PCR and Sanger sequencingï¼ and it showed 100% similarity with the 16S rRNA gene sequence of D. mccartyi strain 195. The anaerobic microbial consortium W-1 was also bioaugmented into the groundwater contaminated by TCE at a concentration of 418.7 µmol·L-1. The results showed that ï¼69.2 ±9.8ï¼% of TCE could be completely detoxified to ethylene within 28 days with a dechlorination rate of ï¼10.3 ±1.5ï¼ µmol·ï¼L·dï¼-1. This study can provide the microbial resource and theoretical guidance for the anaerobic microbial remediation in PCE or TCE-contaminated groundwater.
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Chloroflexi , Dicloruros de Etileno , Tetracloroetileno , Tricloroetileno , Humanos , Anaerobiosis , ARN Ribosómico 16S/genética , Etilenos , Dicloroetilenos , Biodegradación Ambiental , Chloroflexi/genéticaRESUMEN
1,2-Dichloroethane (1,2-DCA) is a ubiquitous volatile halogenated organic pollutant in groundwater and soil, which poses a serious threat to the ecosystem and human health. Microbial reductive dechlorination has been recognized as an environmentally-friendly strategy for the remediation of sites contaminated with 1,2-DCA. In this study, we obtained an anaerobic microbiota derived from 1,2-DCA contaminated groundwater, which was able to sustainably convert 1,2-DCA into non-toxic ethylene with an average dechlorination rate of 30.70 ± 11.06 µM d-1 (N = 6). The microbial community profile demonstrated that the relative abundance of Dehalococcoides species increased from 0.53 ± 0.08% to 44.68 ± 3.61% in parallel with the dechlorination of 1,2-DCA. Quantitative PCR results showed that the Dehalococcoides species 16S rRNA gene increased from 2.40 ± 1.71 × 108 copiesâmL-1 culture to 4.07 ± 2.45 × 108 copiesâmL-1 culture after dechlorinating 110.69 ± 30.61 µmol of 1,2-DCA with a growth yield of 1.55 ± 0.93 × 108 cells per µmol Cl- released (N = 6), suggesting that Dehalococcoides species used 1,2-DCA for organohalide respiration to maintain cell growth. Notably, the relative abundances of Methanobacterium sp. (p = 0.0618) and Desulfovibrio sp. (p = 0.0001995) also increased significantly during the dechlorination of 1,2-DCA and were clustered in the same module with Dehalococcoides species in the co-occurrence network. These results hinted that Dehalococcoides species, the obligate organohalide-respiring bacterium, exhibited potential symbiotic relationships with Methanobacterium and Desulfovibrio species. This study illustrates the importance of microbial interactions within functional microbiota and provides a promising microbial resource for in situ bioremediation in sites contaminated with 1,2-DCA.
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Chloroflexi , Dehalococcoides , Humanos , Dehalococcoides/genética , ARN Ribosómico 16S/genética , Ecosistema , Biodegradación Ambiental , Etilenos , Chloroflexi/genéticaRESUMEN
N(1)-meA and N(3)-meC are cytotoxic DNA base methylation lesions that can accumulate in the genomes of various organisms in the presence of S(N)2 type methylating agents. We report here the structural characterization of these base lesions in duplex DNA using a cross-linked protein-DNA crystallization system. The crystal structure of N(1)-meA:T pair shows an unambiguous Hoogsteen base pair with a syn conformation adopted by N(1)-meA, which exhibits significant changes in the opening, roll and twist angles as compared to the normal A:T base pair. Unlike N(1)-meA, N(3)-meC does not establish any interaction with the opposite G, but remains partially intrahelical. Also, structurally characterized is the N(6)-meA base modification that forms a normal base pair with the opposite T in duplex DNA. Structural characterization of these base methylation modifications provides molecular level information on how they affect the overall structure of duplex DNA. In addition, the base pairs containing N(1)-meA or N(3)-meC do not share any specific characteristic properties except that both lesions create thermodynamically unstable regions in a duplex DNA, a property that may be explored by the repair proteins to locate these lesions.
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Adenosina/análogos & derivados , Citosina/análogos & derivados , Daño del ADN , Enzimas Reparadoras del ADN/química , ADN/química , Dioxigenasas/química , Adenosina/química , Dioxigenasa Dependiente de Alfa-Cetoglutarato, Homólogo 2 de AlkB , Emparejamiento Base , Citosina/química , Metilación de ADN , Modelos MolecularesRESUMEN
Arginine decarboxylase (ADC) catalyzes the decarboxylation of arginine to form agmatine, an important physiological and pharmacological amine, and attracts attention to the enzymatic production of agmatine. In this study, we for the first time overexpressed and characterized the marine Shewanella algae ADC (SaADC) in Escherichia coli. The recombinant SaADC showed the maximum activity at pH 7.5 and 40 °C. The SaADC displayed previously unreported substrate inhibition when the substrate concentration was higher than 50 mM, which was the upper limit of testing condition in other reports. In the range of 1-80 mM L-arginine, the SaADC showed the Km, kcat, Ki, and kcat/Km values of 72.99 ± 6.45 mM, 42.88 ± 2.63 s-1, 20.56 ± 2.18 mM, and 0.59 s/mM, respectively, which were much higher than the Km (14.55 ± 1.45 mM) and kcat (12.62 ± 0.68 s-1) value obtained by assaying at 1-50 mM L-arginine without considering substrate inhibition. Both the kcat values of SaADC with and without substrate inhibition are the highest ones to the best of our knowledge. This provides a reference for the study of substrate inhibition of ADCs.
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Proteínas Bacterianas/metabolismo , Carboxiliasas/metabolismo , Escherichia coli/genética , Shewanella/enzimología , Agmatina/metabolismo , Arginina/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Proteínas Bacterianas/aislamiento & purificación , Carboxiliasas/química , Carboxiliasas/genética , Carboxiliasas/aislamiento & purificación , Codón , Expresión Génica , Concentración de Iones de Hidrógeno , Cinética , Modelos Moleculares , Estabilidad Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/aislamiento & purificación , Proteínas Recombinantes/metabolismo , TemperaturaRESUMEN
This study reported the cloning, expression, and characterization of a new salt-tolerant leucine dehydrogenase (PrLeuDH) from Pseudoalteromonas rubra DSM 6842. A codon-optimized 1038 bp gene encoding PrLeuDH was successfully expressed on pET-22b( +) in E. coli BL21(DE3). The purified recombinant PrLeuDH showed a single band of about 38.7 kDa on SDS-PAGE. It exhibited the maximum activity at 40 °C and pH 10.5, while kept high activities in the range of 25-45 °C and pH 9.5-12. The Km value and turnover number kcat for leucine of PrLeuDH were 2.23 ± 0.12 mM and 35.39 ± 0.05 s-1, respectively, resulting in a catalytic efficiency kcat/Km of 15.87 s-1/mM. Importantly, PrLeuDH remained 92.1 ± 2.67% active in the presence of 4.0 M NaCl. The study provides the first in-depth understanding of LeuDH from marine Pseudoalteromonas rubra, meanwhile the unique properties of high activity at low temperature and high salt tolerance make it a promising biocatalyst for the synthesis of non-protein amino acids and α-ketoacids under special conditions in pharmaceutical industry.
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Escherichia coli , Pseudoalteromonas , Clonación Molecular , Estabilidad de Enzimas , Escherichia coli/genética , Concentración de Iones de Hidrógeno , Leucina/genética , Leucina-Deshidrogenasa , Pseudoalteromonas/genética , Proteínas Recombinantes/genética , Cloruro de SodioRESUMEN
The functional roles of microRNAs (miRNAs) have been studied in various diseases, including hypoxic-ischemic brain damage (HIBD). However, changes in the expression of miRNAs and the underlying mechanisms in the pineal gland during HIBD remain unknown. Based on the previous study by microRNA array, hundreds of miRNAs showed altered expression patterns in the pineal gland in a rat model of HIBD. MiR-375-3p was found to be significantly upregulated and abundant in the pineal gland. Further investigation in an in vitro HI model of pinealocytes showed that miRNA-375 exacerbated the damage to pineal function. After oxygen-glucose deprivation / reoxygenation (OGD/R), miR-375-3p expression increased, while aralkylamine N-acetyltransferase (AANAT) expression and melatonin (MT) secretion decreased. Overexpression of miRNA-375 in pinealocytes aggravated the influence of OGD/R on AANAT expression and MT secretion. Because miRNA-375 overexpression in pinealocytes induced decreased rasd1 mRNA and protein expression, rasd1 may mediate the effect of miR-375-3p on pineal function. Furthermore, miR-375-3p aggravated the cognitive impairment caused by HIBD in rats, as observed by Morris water maze test, and also affected emotion and circadian rhythm in HIBD-treated rats. Thus, miR-375-3p may be a key regulatory molecule in the pineal gland following HIBD, and targeting of miR-375-3p may represent a new strategy for the treatment of HIBD.
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Hipoxia-Isquemia Encefálica/fisiopatología , MicroARNs/metabolismo , Glándula Pineal/fisiopatología , Animales , Ritmo Circadiano/fisiología , Disfunción Cognitiva/etiología , Disfunción Cognitiva/metabolismo , Disfunción Cognitiva/fisiopatología , Emociones/fisiología , Femenino , Hipoxia-Isquemia Encefálica/complicaciones , Hipoxia-Isquemia Encefálica/metabolismo , Masculino , Glándula Pineal/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Bacillus anthracis, the causative agent of anthrax, is a dangerous biological weapon, as spores derived from drug-resistant strains cause infections for which antibiotic therapy is no longer effective. We sought to develop an anti-infective therapy for anthrax and targeted CapD, an enzyme that cleaves poly-gamma-D-glutamate capsule and generates amide bonds with peptidoglycan cross-bridges to deposit capsular material into the envelope of B. anthracis. In agreement with the model that capsule confers protection from phagocytic clearance, B. anthracis capD variants failed to deposit capsule into the envelope and displayed defects in anthrax pathogenesis. By screening chemical libraries, we identified the CapD inhibitor capsidin, 4-[(4-bromophenyl)thio]-3-(diacetylamino)benzoic acid), which covalently modifies the active-site threonine of the transpeptidase. Capsidin treatment blocked capsular assembly by B. anthracis and enabled phagocytic killing of non-encapsulated vegetative forms.
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Aminobenzoatos/farmacología , Carbunco/microbiología , Bacillus anthracis/enzimología , Cápsulas Bacterianas/metabolismo , Peptidoglicano/metabolismo , Peptidil Transferasas/metabolismo , Sulfuros/farmacología , Animales , Antibacterianos/farmacología , Bacillus anthracis/efectos de los fármacos , Bacillus anthracis/genética , Bacillus anthracis/patogenicidad , Cápsulas Bacterianas/efectos de los fármacos , Femenino , Cobayas , Peptidil Transferasas/genética , Ácido Poliglutámico/análogos & derivados , Ácido Poliglutámico/metabolismo , VirulenciaRESUMEN
Early-onset sepsis (EOS) in neonates is a serious disease with severe complications. The increased severity of EOS and risk of death in newborns in recent years signify that continued monitoring to detect possible changes in the pathogen etiology, disease severity, and disease outcome is particularly important. We conducted a retrospective study on early-onset infection among infants (birth weights > 800 g) who were hospitalized in the Children's Hospital of Soochow University from January 1, 2011, to December 31, 2017. Multivariable analysis was performed to determine the significant predictors of mortality. The most frequent early-onset pathogen was Group B Streptococcus (GBS) (28.1%), followed by Escherichia coli (21.6%), Listeria monocytogenes (11.8%), and Klebsiella pneumoniae (7.8%). Most infants (85.6%) with early-onset infections survived until hospital discharge, while 44 (14.4%) patients died. Multivariable logistic regression analysis showed that the significant predictors of mortality were the pathogen (GBS, E. coli, or other pathogens) and birth weight (both P < 0.01). GBS remains the most frequent pathogen known to infect infants. E coli was the most common pathogen associated with neonatal mortality. Prevention of E. coli sepsis, specifically among preterm infants, remains a challenge.
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Infecciones por Bacterias Gramnegativas/sangre , Infecciones por Bacterias Grampositivas/sangre , Sepsis/microbiología , Sepsis/mortalidad , China/epidemiología , Femenino , Bacterias Gramnegativas/patogenicidad , Bacterias Grampositivas/patogenicidad , Hospitalización/estadística & datos numéricos , Humanos , Incidencia , Recién Nacido , Masculino , Estudios Retrospectivos , Factores de Riesgo , Índice de Severidad de la Enfermedad , Factores de TiempoRESUMEN
This study reported simultaneously improved thermostability and hydrolytic pattern of α-amylase from Bacillus subtilis CN7 by rationally engineering the mostly conserved central beta strands in TIM barrel fold. Nine single point mutations and a double mutation were introduced at the 2nd site of the ß7 strand and 3rd site of the ß5 strand to rationalize the weak interactions in the beta strands of the TIM barrel of α-amylase. All the five active mutants changed the compositions and percentages of maltooligosaccharides in final hydrolytic products compared to the product spectrum of the wild-type. A mutant Y204V produced only maltose, maltotriose, and maltopentaose without any glucose and maltotetraose, indicating a conversion from typical endo-amylase to novel maltooligosaccharide-producing amylase. A mutant V260I enhanced the thermal stability by 7.1 °C. To our best knowledge, this is the first report on the simultaneous improvement of thermostability and hydrolytic pattern of α-amylase by engineering central beta strands of TIM barrel and the novel "beta strands" strategy proposed here may be useful for the protein engineering of other TIM barrel proteins.
Asunto(s)
Bacillus subtilis/enzimología , Páncreas/enzimología , Ingeniería de Proteínas/métodos , alfa-Amilasas/química , Animales , Aspergillus oryzae , Bacillus amyloliquefaciens , Bacillus licheniformis , Glucosa/química , Hidrólisis , Maltosa/análogos & derivados , Maltosa/química , Mutagénesis Sitio-Dirigida , Oligosacáridos/química , Mutación Puntual , Estructura Secundaria de Proteína , Pseudoalteromonas , Pyrococcus , Porcinos , Temperatura , Trisacáridos/químicaRESUMEN
A diazirine-based nucleoside analogue (DBN) efficiently forms DNA interstand cross-linking under near-UV irradiation. This new base analogue may find broad applications in biotechnology and phototherapy.
Asunto(s)
ADN/química , ADN/efectos de la radiación , Diazometano/análogos & derivados , Nucleósidos/química , Diazometano/síntesis química , Diazometano/química , Modelos Moleculares , Nucleósidos/síntesis química , Procesos Fotoquímicos , Termodinámica , Rayos UltravioletaRESUMEN
An efficient synthesis of 2,3,4-trisubstituted pyrroles via intermolecular cyclization of alkylidenecyclopropyl ketones with amines was observed. The addition of anhydrous MgSO4 improved the yields of the products 3. A possible mechanism involving the distal cleavage of the C-C bond of cyclopropane ring was proposed.
RESUMEN
OBJECTIVES: This retrospective study was aimed to explore the epidemiological and clinical profiles of Mycoplasma pneumoniae infection in neonates. METHODS: From 2011 to 2014, 1322 hospitalized neonates with lower respiratory tract infections were screened for Mycoplasma pneumoniae by detection of Mycoplasma pneumoniae antibodies using Serion ELISA classic Mycoplasma pneumoniae kits. RESULTS: Mycoplasma pneumoniae was identified in 89 (6.7%) patients. The age ranged from 1 day to 28 days with a median of 22 days. The male to female ratio was 1.15:1. Mycoplasma pneumoniae infection peaked in spring (from March through May) and winter (from December through February). Compared with non-Mycoplasma pneumoniae infected neonates, those with Mycoplasma pneumoniae infection were older, presented fever more frequently, and had less tachypnea. CONCLUSIONS: Mycoplasma pneumoniae could be an important etiologic agent for respiratory tract infection in neonates. In neonates Mycoplasma pneumoniae infection was usually associated with older age, presence of fever, and less tachypnea. Mycoplasma pneumoniae infection in neonates tends to be a mild process.