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Burkholderia sp. GB-01 strain was used to study different factors affecting its growth for inoculum production and then evaluated for abamectin degradation in soil for optimization under various conditions. The efficiency of abamectin degradation in soil by strain GB-01 was seen to be dependent on soil pH, temperature, initial abamectin concentration, and inoculum size along with inoculation frequency. Induction studies showed that abamectin depletion was faster when degrading cells were induced by pre-exposure to abamectin. Experiments performed with varying concentrations (2-160 mg Kg(-1)) of abamectin-spiked soils showed that strain GB-01 could effectively degrade abamectin over the range of 2-40 mg Kg(-1). The doses used were higher than the recommended dose for an agricultural application of abamectin, taking in account the over-use or spill situations. A cell density of approximately 10(8) viable cells g(-1) dry weight of soil was found to be suitable for bioremediation over a temperature range of 30-35°C and soil pH 7.5-8.5. This is the first report on bacterial degradation of abamectin in soil by a Burkholderia species, and our results indicated that this bacterium may be useful for efficient removal of abamectin from contaminated soils.
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Burkholderia/metabolismo , Ivermectina/análogos & derivados , Contaminantes del Suelo/metabolismo , Animales , Antiparasitarios/metabolismo , Antiparasitarios/toxicidad , Carga Bacteriana , Biodegradación Ambiental , Burkholderia/crecimiento & desarrollo , Contaminación Ambiental/prevención & control , Concentración de Iones de Hidrógeno , Insecticidas/metabolismo , Insecticidas/toxicidad , Ivermectina/metabolismo , Contaminantes del Suelo/toxicidad , TemperaturaAsunto(s)
Colecistitis/complicaciones , Neoplasias de la Vesícula Biliar/patología , Linfoma Folicular/patología , Anciano , Colecistectomía , Colecistitis/cirugía , Colelitiasis/complicaciones , Colelitiasis/cirugía , Procedimientos Quirúrgicos Electivos , Neoplasias de la Vesícula Biliar/complicaciones , Neoplasias de la Vesícula Biliar/diagnóstico , Neoplasias de la Vesícula Biliar/cirugía , Humanos , Linfoma Folicular/complicaciones , Linfoma Folicular/diagnóstico , Linfoma Folicular/cirugía , MasculinoRESUMEN
We present the case of a 31-year-old woman who underwent surgical excision for a polypoid, vulvar lesion. Histopathological analysis showed a diffuse myxoid stroma admixed with scant collagen fibrils. Thin-walled and branching blood vessels were prominent, with a mild perivascular lymphocytic infiltrate. Cytologically bland spindle cells with inconspicuous nucleoli were immersed in a loose myxoid stroma. This combination of histopathological features along with multinodularity in the subcutaneous fat raised concern for deep angiomyxoma, a locally destructive neoplasm. Among our differential of myxoid lesions of the vulva, we ultimately favored the diagnosis of vulvar cutaneous myxoma. Upon further investigation, we learned that our patient was indeed known for the Carney complex. We highlight that vulvar cutaneous myxomas arising in the context of the Carney complex pose a significant diagnostic challenge for pathologists and should not be overdiagnosed as aggressive lesions such as deep angiomyxoma or other malignant stromal neoplasms.
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Complejo de Carney/patología , Neoplasias Cutáneas/patología , Neoplasias de la Vulva/patología , Adulto , Biomarcadores de Tumor/metabolismo , Complejo de Carney/diagnóstico , Complejo de Carney/metabolismo , Femenino , Humanos , Neoplasias Cutáneas/diagnóstico , Neoplasias Cutáneas/metabolismo , Neoplasias de la Vulva/diagnóstico , Neoplasias de la Vulva/metabolismoRESUMEN
Based on analyzing the bearing capacity of existing T-beam bridges in service, the factors that affect the T-beams cracked by chloride ions mainly include the width and the depth of cracks. Combined with practical engineering examples, a single-piece T-beam model is established to explore the influence of factors such as crack width and crack depth on the T-beams affected by chloride ion erosion through numerical simulation in this paper. In addition, the attenuation models of bending capacity and shear capacity of the T-beam are obtained to analyze the possible failure modes of T-beams with cracks. All of which provides a reference for exploring the effect of crack width and depth on the durability of reinforced concrete members under chloride ion field.
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Composed of multi-strand parallel high-strength wires or steel strands, the stayed cables have been widely used recently in stayed bridges or suspension bridges owing to their light weight and high bearing capacity, especially the steel strands. Meanwhile, chloride-induced corrosion of steel strands is one of the most considerable factors for the durability of the stayed cable exposed to marine environments. The fatigue caused by both cyclic loading and corrosion can affect the life of the steel strands. Besides, the current studies related to the effects of the aforementioned two impact factors on the life of the steel strands either considered the fatigue only, or took the two impact factors into account separately. The coupling effects of fatigue and corrosion on the life of the steel strands are required to be further explored and discussed. Consequently, it is essential to create a model to predict the life of the steel strands with the coupling effects taken into consideration. In this paper, an indoor physical experiment of the steel strand specimens exposed to marine tidal environment was carried out. To avoid accidental errors, the whole specimens were divided into 20 groups, with each group having two steel wires with a 5 days, 10 days, and 15 days cycle for the test. The corrosion of steel strands was observed at various exposure times and it was found that the pits were formed on the surface with the chloride ion erosion to the steel strands. Deeper and sharper pits result in greater pitting-local stress and a shorter fatigue life, which is also the main reason for reducing the carrying capacity of the steel strands. However, a detailed description for this problem is lacking in current domestic and foreign literature, because the pit is hard to predict owing to its complex nature. In order to simulate the evolution of the pits, the stochastic pitting-corrosion model was set up by the neural network method to evaluate the pit evolutions over time. In addition, an empirical formula consisting of length-width ratios, length-depth ratios, and depth-to-width ratios of the pits was obtained to determine the stress concentration factor based on the multi-dimensional linear regression method. The fatigue notch factor of components can be deduced by the stress concentration factor, and the life of the steel strands can be deduced by both of them. The findings are expected to be useful in realistically predicting the durability of wire structures.
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BACKGROUND: The research of extracellular matrix stent (ECM) has made some progress in the repair of urethra and bladder defects. OBJECTIVES: To observe the effects of highly bioactive ECM scaffold on the regeneration and repair of defects in long-segment ureteral replacement. MATERIAL AND METHODS: An animal model of long-segment ureteral defect was established and four-layer tubular highly bioactive ECM materials were prepared. After the ureteral defect was repaired through surgery, the rabbits in the negative control group were administered a non-bioactive stent, and rabbits in the observation group were treated with an ECM stent. RESULTS: Comparison of macro-indicators: The negative control group had a higher infection rate, a lower survival rate and more complications than the observation group (p < 0.05). The frequency of ureteral peristalsis in the negative control group was lower than in the observation group. In addition, the rate of urinary dysfunction was higher, and the ratio of ureteral diameter was lower in the negative control group than in the observation group (all p < 0.05). Comparison of histopathology: Three months after the operation, the vascular, smooth muscle and mucous membrane of the ureter in the observation group regenerated to close to normal ureteral tissue. There was no significant difference between the ureter regeneration in the repair area and the normal ureter tissue in the observation group 3 months after the operation. The number of regenerated muscle fibers in the observation group was significantly higher than that of the negative control group. Compared with the negative control group, the fibrous capsule was thicker, the percentages of CD31, CD3, CD68, CD80+, and CD163+ were higher, the scope of new smooth muscle fiber was expanded, fusion with the host muscle fibers was higher, and the neuromuscular junction (NMJ) structure was stronger in the observation group (all p < 0.05). CONCLUSIONS: A highly bioactive ECM stent can better regenerate the local anatomical structure and physiological function.
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Matriz Extracelular , Stents , Uréter , Animales , Conejos , Regeneración , Uréter/cirugía , Vejiga UrinariaRESUMEN
The effects of hydrothermal carbonization (hydrothermal carbonization temperature, hydrothermal carbonization time, pH) on the dehydration performance of dyeing sludge were studied. The specific resistance, viscosity and floccular morphology of sludge before and after hydrothermal carbonization were analyzed. The physical and chemical properties of the liquid were also determined. The results showed that the dehydration performance of sludge was optimum, when the reaction temperature was 180 °C, the reaction time 4 h and the pH was 5.0. Here the specific resistance to filtration and viscosity were 93.69% and 96.78% lower, respectively, than the control group. When the sludge was hydrothermally carbonized, the sludge flocs were broken due to extreme conditions of high temperature and high pressure, which formed a porous mesh structure with better water permeability. The cohesion of the sludge colloidal structure was reduced, the capillary suction time was reduced by 88.89%, and the sludge dewatering performance was improved. This study shows the feasibility of the use of hydrothermal carbonization in sludge reduction.
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Atrazine (AT), a kind of herbicide for the pre and post-emergence control of annual and broad leaved weeds and perennial grasses, had been widely used in the world. However, the extensive use of atrazine had led to widespread environmental pollution. A bacterium strain SA1, which could degrade AT completely, was isolated from an atrazine-degrading consortium by long-time repeated alternative cultivation and plate striking. Combining cultural and physiobiochemical characteristics with 16S rDNA sequence analysis, SA1 was identified as Pseudomonas sp.. SAl could use atrazine as the sole carbon, nitrogen and energy sources for growth, and the main product of AT biodegradation was cyanuric acid. AT degrading activity of SA1 was not affected by the addition of nitrogen resources. However, cyanuric acid could be degraded quickly to an undetectable level when glucose was added. The optimal temperature and pH value for SAl growth was 37 degrees C and pH7, respectively. Atrazine could be degraded efficiently by the resting cells of SAl under the conditions of 10 degrees C - 40 degrees C or pH value 4-11, and SA1 had a wide range of temperature and pH value for AT degradation when compared with ADP. atzABCD and conserved sequence of tnpA gene of IS1071 could be amplified from SA1, and these genes could be lost during subculture.
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Atrazina/metabolismo , Herbicidas/metabolismo , Pseudomonas/aislamiento & purificación , Pseudomonas/metabolismo , Microbiología del Suelo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , ADN Bacteriano/genética , ADN Ribosómico/genética , Datos de Secuencia Molecular , Filogenia , Pseudomonas/clasificación , Pseudomonas/genética , ARN Ribosómico 16S/genéticaRESUMEN
Ectoine was the main compatible solute of moderately halophilic bacteria. In order to clone the ectABC gene which involved in the ectoine biosynthesis pathway from total DNA of moderately halophilic bacteria Halomonas sp. BYS-1, firstly a 750bp fragment of ectABC gene was amplified by PCR using combinations of forward primers and reverse primers designed according to the ectABC genes of Halomonas elongata 2851T and Halomonas elongata DSM3043. Then the upstream and downstream sequences of the 750bp fragment were amplified by SEFA PCR (SElf-Formed Adaptor PCR), a new PCR method amplified relatively long flanking sequences from tagged sequences in a simple way without enzyme excision and ligation. The 3532bp fragment include 2423bp ectABC, 980bp upstream sequences and 129bp downstream sequences were cloned from Halomonas sp. BYS-1 using a pair of conserved primers designed according to acquired sequences by SEFA PCR. The GenBank accession number of the 3532bp fragment is DQ017757. ORF analysis revealed that ectA, ectB, ectC cluster to an operon, the size of ectA, ectB, and ectC were 573bp, 1251bp and 387bp respectively. The predicted molecular masses of the encoded proteins were 21.1kDa (191 amino acids, EctA), 45.7 kDa (417 amino acids, EctB), and 14.5 kDa (129 amino acids, EctC) respectively. The 3532bp fragment was ligated to the MCS site of vector pUC19 and transformed E. coli DH5alpha to construct E. coli (pUC19ECT). Transformant E. coli (pUC19ECT) could synthesis ectoine under salt stress, the intracellular ectoine level were 7.1, 19.4 and 32.3 micromol/(g x dry x wt) when the salinities of the mediums were 0, 0.4 and 0.8mol/L sodium chloride respectively. But the accumulation of ectoine could not promote the growth of E. coli (pUC19ECT)under high salinity.
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Proteínas Bacterianas/metabolismo , Secuencia de Bases , Halomonas/genética , Reacción en Cadena de la Polimerasa/métodos , Aminoácidos Diaminos/síntesis química , Proteínas Bacterianas/genética , Clonación Molecular , Cartilla de ADN , Escherichia coli/metabolismo , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Vectores Genéticos , Cloruro de Sodio/metabolismoRESUMEN
Triazophos is a kind of organophosphorous pesticide which was widely used by farmers all over the world in 1990's. It is effective in controlling pesticide but harmful to human beings. Bioremediation is an effective and economic method to treat environment that has been polluted by hazardous organic compounds, so researchers paid much attention in this area. Most of which focused on isolating functional bacteria, studying its degrading mechanism, and cloning degradation-related genes. MP-4 was isolated from soil polluted by Triazophos for a long time and identified as Ochrobactrum sp.. The triazophos hydrolase (tpd) gene was cloned by the method of shotgun cloning, and the sequences were determined and analyzed. In the former tests it was found that there was only 18 base pairs different in tpd gene from mpd gene, which was isolated from methyl parathion degrading strain Pseudomonas putida DLL-1. Enzyme TPD can hydrolyze triazophos and methyl parathion while MPD cannot hydrolyze triazophos. Pseudomonas putida KT2440 is a metabolically versatile saprophytic soil bacterium that has been certified as a biosafety host for the cloning of foreign genes. This bacterium is known for its diverse metabolism and potential for development of biopesticides and plant growth promoters because of its ability to colonize rhizosphere of crop plants. Tpd gene was isolated from the genomic DNA of Ochrobactrum sp. MP-4 by PCR amplification. Recombinant plasmids pTPD was constructed by ligating tpd gene into broad host vector pBBRMCS-5. With the help of plasmid pRK2013, pTPD was transferred into Pseudomonas putida KT2440 to construct KT2440-DOP. KT2440-DOP can degrade many organophosphate pesticides and aromatics compounds. The specific activity of organophosphate hydrolase of KT2440-DOP was approximately 2 times of MP-4. Later, parameters affecting bioremediation of Organophosphate pesticide in soil using KT2440-DOP will be studied.
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Pseudomonas putida/metabolismo , Biodegradación Ambiental , Insecticidas/metabolismo , Compuestos Organofosforados/metabolismo , Organotiofosfatos/metabolismo , Triazoles/metabolismoRESUMEN
Horizontal gene transfer, unlike vertical gene transfer, is a means of genetic communication in bacteria. In the special polluted environment, horizontal transfer of polluted-degrading gene has significant functions. Study on horizontal transfer of degrading gene in polluted environment may deepen our understanding of the mechanism of bacterial adaptation to the organic-polluted environment. In the practical application in bioremediation, horizontal transfer of degrading gene can be regulated to promote degrading ability of microorganisms. In this article, we will review the advances in the study on mechanisms of genetic interactions among bacteria, the effect of degrading gene transfer in contaminated environment on microorganisms'adaptation to contaminated environment and the degradation of the pollutants.
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Bacterias/metabolismo , Proteínas Bacterianas/metabolismo , Contaminantes Ambientales/metabolismo , Transferencia de Gen Horizontal , Adaptación Fisiológica/genética , Adaptación Fisiológica/fisiología , Bacterias/genética , Bacterias/crecimiento & desarrollo , Proteínas Bacterianas/genética , Restauración y Remediación Ambiental/métodosRESUMEN
A moderately halophilic bacterium(designated strain I15) was isolated from lawn soil. Based on the analysis of 16S rDNA (GenBank accession number DQ010162), morphology, physiological and biochemical characteristics, strain I15 was identified as Virgibacillus marismortuii. This strain was capable of growing under 0% approximately 25% NaCl, and exhibited an optimum NaCl concentration of 10% and an optimum temperature of 30 degrees C and an optimum pH of 7.5 - 8.0 for its growth, respectively. Under hyperosmotic stress, strain 115 accumulated ectoine as the main compatible solute. Under 15% NaCl conditions the intracellar ectoine can reach to 1.608 mmol/(g x cdw), accounted for 89.6% of the total compatible solutes. The biosynthesis of ectoine was under the control of osmotic, and the accumulated ectoine synthesized intraceilularly can released under hypoosmotic shocks and resynthesis under hyperosmotic shock rapidly.
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Aminoácidos Diaminos/metabolismo , Bacterias/aislamiento & purificación , Microbiología del Suelo , Bacterias/clasificación , Bacterias/crecimiento & desarrollo , Bacterias/metabolismo , FilogeniaRESUMEN
Atrazine could be used as the sole carbon, nitrogen and energy sources for growth by strain Arthrobacter sp. AG1, and the atrazine-degrading genes of AG1 were found to be the combination of trzN, atzB and atzC. The atrazine chloride hydrolysase gene trzN was cloned by PCR amplification,whose sequence shared 99% identity with that of Norcardioides sp. C190. Two large plasmids were found in AG1,and trzN and atzB were confirmed to be localized on the larger plasmid pAG1 by the method of southern hybridization. Subculture of AG1 in liquid LB for three generations, 34% of the subsequent cells were found to lose degrading activity, however, neither plasmid was lost. PCR amplification results showed that the mutants had only lost the trzN gene instead of atzB and atzC. It was deduced that mutation might be due to the trzN gene deletion from the plasmid. This study provided new evidence that atrazine metabolic genotypes were resulted from horizontal gene transfer between different bacteria under environmental selective pressure.
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Arthrobacter/genética , Atrazina/metabolismo , Genes Bacterianos/genética , Biodegradación Ambiental , Herbicidas/metabolismoRESUMEN
A monocrotophos [dimethyl (E)-1-2-methylcarbamoylvinylphosphate or MCP] -degrading strain named as M-1 was isolated from sludge collected from the wastewater treatment pool of a pesticide factory and identified as Paracoccus sp. according to its morphology and biochemical properties and 16S rDNA sequence analysis. Using MCP as a sole carbon source, M-1 was able to degrade MCP(100 mg x L(-1)) by 92.47% in 24 h. The key enzyme(s) involved in the initial biodegradation of monocrotophos in M-1 was shown to be constitutively expressed cytosolic proteins and showed the greatest activity at pH 8.0 and 25 degrees C, with its Michaelis-Mentn's constant (K(m)) and maximum degradation rate (V(max)) of 0.29 micromol x mL(-1) and 682.12 micromol (min x mg)(-1) respectively. This degrading enzyme(s) was sensitive to high temperature, but kept high activity under alkaline conditions.
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Monocrotofos/metabolismo , Paracoccus/aislamiento & purificación , Paracoccus/metabolismo , Aguas del Alcantarillado/microbiología , Biodegradación Ambiental , Paracoccus/genética , ARN Ribosómico 16S/genética , TemperaturaRESUMEN
Construction of multifunctional pesticides-degrading genetically engineered microorganisms (GEMs) is increasing important in the bioremediation of various pesticides contaminants in environment. However, construction of genetically stable GEMs without any exogenous antibiotic resistance is thought to be one of the bottlenecks in GEMs construction. In this article, homologous recombination vectors with the recipient's 16S rDNA as homologous recombination directing sequence (HRDS) and sacB gene as double crossover recombinants positive selective marker were firstly constructed. The methyl parathion hydroalse gene (mpd) was inserted into the 16S rDNA site of the carbofuran degrading strain Sphingomonas sp. CDS-1 by homologous recombination single crossover in the level of about 3.7 x 10-(7) - 6.8 x 10(-7). Multifunctional pesticides-degrading GEMs with one or two mpd genes inserted into the chromosome without any antibiotic marker were successfully constructed. The homologous recombination events were confirmed by PCR and southern blot methods. The obtained GEMs were genetically stable and could degrade methyl parathion and carbofuran simultaneously. The insertion of mpd gene into rrn site did not have any significant effect on recipient' s physiological and original degrading characteristics. The methyl parathion hydrolase (MPH) was expressed at a relatively high level in the recombinants and the recombinant MPH specific activity in cell lysate was higher than that of original bacterium (DLL-1) in every growth phase tested. The highest recombinant MPH specific activity was 6.22 mu/tg. In this article, we describe a first attempt to use rRNA-encoding regions of Sphingomonas strains as target site for expression of exogenous MPH, and constructed multifunctional pesticides degrading GEMs, which are genetically stable and promising for developing bioremediation strategies for the decontamination of pesticides polluted soils.