ABSTRACT
Microorganisms are the dominant players driving the degradation and transformation of chloramphenicol (CAP) in the environment. However, little bacterial strains are able to efficiently degrade and mineralize CAP, and the CAP degrading pathways mediated by oxidative reactions remain unclear. In this study, a highly efficient CAP-degrading microbial consortium, which mainly consists of Rhodococcus (relative abundance >70%), was obtained through an enrichment process using CAP-contaminated activated sludge as the inoculum. A bacterial strain CAP-2 capable of efficiently degrading CAP was isolated from the consortium and identified as Rhodococcus sp. by 16S rRNA gene analysis. Strain CAP-2 can efficiently degrade CAP under different nutrient conditions. Based on the biotransformation characteristics of the detected metabolite p-nitrobenzoic acid and the reported metabolites p-nitrobenzaldehyde and protocatechuate by strain CAP-2, a new oxidative pathway for the degradation of CAP was proposed. The side chain of CAP was oxidized and broken to generate p-nitrobenzaldehyde, which was further oxidized to p-nitrobenzoic acid. Strain CAP-2 can be used to further study the molecular mechanism of CAP catabolism, and has the potential to be used in in situ bioremediation of CAP-contaminated environment.
Subject(s)
Biodegradation, Environmental , Chloramphenicol , RNA, Ribosomal, 16S/genetics , Rhodococcus/genetics , SewageABSTRACT
Objective@#To investigate the changes of brain gray matter volume in patients with occupational noise-induced hearing loss by voxel based morphometry (VBM) .@*Methods@#16 age-and education-matched healthy controls and 42 patients with occupational noise induced hearing loss, including 27 in mild group and 15 in severe group, received MRI 3D-FSPGR sequence T1WI sagittal scan, and then underwent VBM of brain gray matter volume data analysis.@*Results@#The brain gray matter volume of the left occipitotemporal lateral gyrus, the anterior cingulate gyrus, the bilateral angular gyrus, the precuneus and the near midline area of cerebellum differed between experimental group and control group (P<0.01) .@*Conclusion@#The volume of gray matter in specific brain areas of patients with occupational noise-induced hearing loss was changed, and the effect of noise on brain structure was revealed from the perspective of imaging.
ABSTRACT
In this study, we investigated reductive degradation of nitroaromatic antibiotic chloramphenicol to non-effective antibacterial amine product in fed-batch biocatalyzed electrolysis systems (BES) (applied voltage was 0.5 V) under low temperature (12 +/- 2 degrees C). The ohm resistance of the whole BES reactor increased when the phosphate buffer solution concentrations decreased. Efficiencies (ErCAP) of chloramphenicol reduction with biocathode (PBS, 25 mmol/L) in presence of glucose was (86.3 +/- 1.69)% within 24 h and sludge fermentation liquor was (74.1 +/-1.44)% within 24 h. While the ErCAP of abiotic cathode under the same condition was only (57.9 +/- 1.94)% within 24 h. It suggested that biocathode could be a promising technology for reductive biodegradation of nitroaromatic antibiotics-containing wastewater in areas with relatively low annual mean temperature.
Subject(s)
Bioreactors , Chloramphenicol , Metabolism , Electrochemical Techniques , Methods , Electrodes , Fermentation , Oxidation-ReductionABSTRACT
Objective To explore the sensibility of radiation-induced normal brain injury in different regions at acute stage after all cranial radiotherapy by MR diffusion tensor imaging (DTI).Methods A total of 44 patients with brain tumors undergoing whole cranial radiotherapy were examined with convention and enhancement magnetic resonance imaging and diffusion tensor imaging before and three weeks after radiotherapy.The apparent diffusion coefficient ( ADC ),fractional anisotropy ( FA),relative anisotropy (RA) and volume ratio(VR) of DTI in contralateral brain hemisphere after radiotherapy with the dose of 27 Gy were measured and analyzed in different regions.Results No abnormal signal intensities were revealed in convention and enhancement MRI.ADC values in superficial cerebral convolution gray matter,ADC and VR values in deep gray nucleus were increased(t =- 3.321,- 2.810,P ＜ 0.05 ),while FA and RA values in deep gray nucleus were descended( t =2.906,2.349,P ＜0.05 ).There was no statistically significant difference among DTI index in other regions.Conclusions The brain gray matter more sensitive to radiation-induced brain injury in than white matter at acute stage of radiation.DTI could be used to evaluate the functional changes at the histocytology level of radiation-induced brain injury,and to explain the early clinical reactions after radiotherapy.
ABSTRACT
Hydrogen production from lignocellulosic biomass is both sustainable and environmentally friendly, which is garnering more and more attention across the world, with an expectation to challenge the shortage of fossil fuels supply and climate change as well. In this article, the update research progress and technology development of biohydrogen production are reviewed, with a focus on biomass pretreatment, hydrogen-producing microorganisms and process engineering strategies. And in the meantime, a roadmap for more efficient and economic biohydrogen production is envisioned.
Subject(s)
Bacteria , Metabolism , Bioelectric Energy Sources , Microbiology , Biomass , Biotransformation , Fermentation , Hydrogen , Metabolism , Lignin , MetabolismABSTRACT
Objective To investigate the effect of hirudo micropowder on inflammatory factors in rats with cerebral ischemia-reperfusion injury.Methods Rats were randomly divided into sham-operation group,model group,coarse powder hirudo group,high-,middle-and low-dose micropowder hirudo groups.The corresponding drugs were given to the rats for 10 days by intragastric administration.Then middle cerebral artery occlusion(MCAO) model was made by suture method.The changes of inflammatory factors were observed.Results The level of intercellular adhesion molecule 1(ICAM-1) in high-dose micropowder hirudo group was lower than that in coarse powder hirudo group,and the level of platelet-derived growth factor(PDGF) in middle-and high-dose micropowder hirudo groups was also lower than that in coarse powder hirudo group obviously(P