Microbial population responses to pH and salt shock during phenols degradation under high salt conditions revealed by RISA and AFDRA

2013 ◽  
Vol 67 (3) ◽  
pp. 527-534 ◽  
Author(s):  
Bin Yan ◽  
Ping Wang ◽  
Wenchao Liao ◽  
Qian Ye ◽  
Meilan Xu ◽  
...  
Keyword(s):  
Removal Rate ◽  
Restriction Analysis ◽  
Intergenic Spacer ◽  
Alcaligenes Faecalis ◽  
High Salt ◽  
Dna Fingerprint ◽  
Salt Shock ◽  
Alkaline Conditions ◽  
Functional Dna ◽  
High Level

The responses of microbial community to pH and salt shock during phenols degradation under high salt conditions were revealed by two DNA fingerprint methods, i.e. ribosomal intergenic spacer analysis (RISA) and amplified functional DNA restriction analysis (AFDRA), together with 16S rDNA clone library analysis. It was shown that the phenols removal rate was improved with increasing NaCl concentration from 0 to 50 mg/L, and could remain at a high level even in the presence of 100 mg/L NaCl. The degradation efficiency remained stable under neutral conditions (pH 7.0–9.0), but decreased sharply under acidic (below pH 5.0) or more alkaline conditions (above pH 10.0). The community structure was dramatically changed during salt fluctuations, with Halomonas sp. and Marinobacter sp. as the predominant salt-tolerant species. Meanwhile, Marinobacter sp. and Alcaligenes faecalis sp. were the major species which might play the key role for stabilizing the treatment systems under different pH conditions. Moreover, the changes of phenol hydroxylase genes were analyzed by AFDRA, which showed that these functional genes were substantially different under any shock conditions.

Relations between carbon removal rates, biofilm size and density of a novel anaerobic reactor: the inverse turbulent bed

2000 ◽  
Vol 41 (4-5) ◽  
pp. 253-260 ◽  
Author(s):  
P. Buffière ◽  
R. Moletta
Keyword(s):  
Removal Rate ◽  
Removal Rates ◽  
Carbon Removal ◽  
Biofilm Growth ◽  
Loading Rates ◽  
Biomass Activity ◽  
High Turbulence ◽  
The One ◽  
High Level ◽  
Very High

An anaerobic inverse turbulent bed, in which the biogas only ensures fluidisation of floating carrier particles, was investigated for carbon removal kinetics and for biofilm growth and detachment. The range of operation of the reactor was kept within 5 and 30 kgCOD· m−3· d−1, with Hydraulic Retention Times between 0.28 and 1 day. The carbon removal efficiency remained between 70 and 85%. Biofilm size were rather low (between 5 and 30 μm) while biofilm density reached very high values (over 80 kgVS· m−3). The biofilm size and density varied with increasing carbon removal rates with opposite trends; as biofilm size increases, its density decreases. On the one hand, biomass activity within the reactor was kept at a high level, (between 0.23 and 0.75 kgTOC· kgVS· d−1, i.e. between 0.6 and 1.85 kgCOD·kgVS · d−1).This result indicates that high turbulence and shear may favour growth of thin, dense and active biofilms. It is thus an interesting tool for biomass control. On the other hand, volatile solid detachment increases quasi linearly with carbon removal rate and the total amount of solid in the reactor levels off at high OLR. This means that detachment could be a limit of the process at higher organic loading rates.

Low Alkaline Cement Used in the Construction of a Gallery in the Horonobe Underground Research Laboratory

2010 ◽  
Author(s):  
Masashi Nakayama ◽  
Haruo Sato ◽  
Yutaka Sugita ◽  
Seiji Ito ◽  
Masashi Minamide ◽  
...  
Keyword(s):  
Fly Ash ◽  
Research Laboratory ◽  
Concrete Lining ◽  
Energy Agency ◽  
Tunnel Support ◽  
Long Term Stability ◽  
Alkaline Conditions ◽  
High Level ◽  
Underground Research Laboratory

In Japan, any high level radioactive waste (HLW) repository is to be constructed at over 300 m depth below surface. Tunnel support is used for safety during the construction and operation, and shotcrete and concrete lining are used as the tunnel support. Concrete is a composite material comprised of aggregate, cement and various admixtures. Low alkaline cement has been developed for the long term stability of the barrier systems whose performance could be negatively affected by highly alkaline conditions arising due to cement used in a repository. Japan Atomic Energy Agency (JAEA) has developed a low alkaline cement, named as HFSC (Highly Fly-ash Contained Silicafume Cement), containing over 60 wt% of silica-fume (SF) and fly-ash (FA). HFSC was used experimentally as the shotcrete material in construction of part of the 140m deep gallery in the Horonobe Underground Research Laboratory (URL). The objective of this experiment was to assess the performance of HFSC shotcrete in terms of mechanics, workability, durability, and so on. HFSC used in this experiment is composed of 40 wt% OPC (Ordinary Portland Cement), 20 wt% SF, and 40 wt% FA. This composition was determined based on mechanical testing of various mixes of the above components. Because of the low OPC content, the strength of HFSC tends to be lower than that of OPC. The total length of tunnel using HFSC shotcrete is about 73 m and about 500 m3 of HFSC was used. The workability of HFSC shotcrete was confirmed in this experimental construction.

scholarly journals Intergenic Spacer Length Variability in Cultivated, Weedy and Wild Rye Species

2015 ◽  
Vol 10 (1) ◽  
Author(s):  
L. Skuza ◽  
E. Filip ◽  
I. Szućko
Keyword(s):  
Intergenic Spacer ◽  
Repetitive Elements ◽  
Universal Primers ◽  
Closely Related Species ◽  
Spacer Length ◽  
Coding Regions ◽  
Similarity Group ◽  
Rdna Igs ◽  
High Level ◽  
Ribosomal Rrna

AbstractNon-coding rDNA spacers (IGS) can vary substantially in size due to differences in the number of repetitive elements among closely related species. Three pairs of universal primers were used in this study for the amplification of non-coding regions of ribosomal (rRNA) IGS. The amplified IGS products obtained from 19 Secale accessions, which included both cultivated and noncultivated rye and which represented three species and four subspecies of the genus Secale, showed a high level of polymorphism. The PCR results were characterized by multiple bands (1-6), different sizes (750bp-3250bp) and 100% polymorphism. Cluster analysis using the neighborjoining method based on the Dice’s coefficient of genetic similarity showed a division of the studied species into two similarity groups. All the studied Secale cereale ssp. cereale were found to belong to the same similarity group. The variation in the size of the IGS among the species which was detected in this study could be due to dissimilarity between the sequences of their respective repetitive elements or between their tandem repeat numbers. The highly interspecific polymorphisms for the rDNA IGS regions suggested that IGS might be a useful molecular marker in studies of Secale species.

Study on Catalytic Steam Reforming of Toluene over Ni/Activated Carbon Catalysts Prepared from Adsorption Treatment of Nickel Electroplating Wastewater by Activated Carbon

2019 ◽  
Vol 797 ◽  
pp. 92-101 ◽  
Author(s):  
Xiao Fang Chen ◽  
Ning Jiang ◽  
Song Hu ◽  
Li Mo He ◽  
Guang Liao ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Steam Reforming ◽  
Removal Rate ◽  
Nickel Particle ◽  
Nickel Ions ◽  
Electroplating Wastewater ◽  
Nickel Electroplating ◽  
Alkaline Conditions ◽  
Steam Reforming Of Toluene ◽  
Catalytic Steam Reforming

The conditions (adsorption duration and pH) for removal of nickel ions from nickel electroplating wastewater by adsorbing on activated carbon were studied. Ni/AC catalysts prepared by adsorption under alkaline conditions with high removal rate of Ni(II) has been chosen for catalytic steam reforming of toluene, and its catalytic performances were evaluated compared to that of Ni/AC catalysts prepared by impregnation. Alkaline conditions facilitated the removal of Ni(II) from nickel electroplating wastewater by AC and pH=9 in especial, was a critical point above which Ni(II) could be removed efficiently. The removal rate within 20 min reached up to more than 97%. After H2 reduction, the catalytic activity of Ni/AC-Ad was observed in catalytic steam reforming of toluene and then gradually decreased with the reaction time. Both the toluene conversion and hydrogen production with Ni/AC-Ad were about 65% of those with Ni/AC-Im at similar Ni loading rate. Under alkaline conditions, most of the nickel adsorbed on AC was Ni(OH)2 complex. This adsorption state led to a larger average size of nickel particle in Ni/AC-Ad than that in Ni/AC-Im. The uneven size of nickel particles on the surface caused poor dispersion of active spots, agglomeration and sintering, resulting in gradual deactivation of Ni/AC-Ad prepared under alkaline conditions during catalytic steam reforming of toluene.

scholarly journals Molecular Epidemiology of Clinical Isolates of Carbapenem-Resistant Acinetobacter spp. from Chinese Hospitals

2007 ◽  
Vol 51 (11) ◽  
pp. 4022-4028 ◽  
Author(s):  
Hui Wang ◽  
Ping Guo ◽  
Hongli Sun ◽  
He Wang ◽  
Qiwen Yang ◽  
...  
Keyword(s):  
Molecular Epidemiology ◽  
Restriction Analysis ◽  
Carbapenem Resistance ◽  
Clinical Isolates ◽  
Teaching Hospitals ◽  
Class 1 Integron ◽  
Carbapenemase Gene ◽  
Class 1 ◽  
Clonal Spread ◽  
High Level

ABSTRACT Carbapenem resistance in Acinetobacter spp. is an emerging problem in China. We investigated the molecular epidemiology and carbapenemase genes of 221 nonrepetitive imipenem-resistant clinical isolates of Acinetobacter spp. collected from 1999 to 2005 at 11 teaching hospitals in China. Genotyping by pulsed-field gel electrophoresis (PFGE) found 15 PFGE patterns. Of these, one (clone P) was identified at four hospitals in Beijing and another (clone A) at four geographically disparate cities. Most imipenem-resistant isolates exhibited high-level resistance to all β-lactams and were only susceptible to colistin. bla OXA-23-like genes were found in 97.7% of isolates. Sequencing performed on 60 representative isolates confirmed the presence of the bla OXA-23 carbapenemase gene. Analysis of the genetic context of bla OXA-23 showed the presence of ISAba1 upstream of bla OXA-23. All of the 187 A. baumannii isolates identified by amplified RNA gene restriction analysis carried a bla OXA-51-like oxacillinase gene, while this gene was absent from isolates of other species. Sequencing indicated the presence of bla OXA-66 for 18 representative isolates. Seven isolates of one clone (clone T) carried the plasmid-mediated bla OXA-58 carbapenemase gene, while one isolate of another clone (clone L) carried the bla OXA-72 carbapenemase gene. Only 1 isolate of clone Q carried the bla IMP-8 metallo-β-lactamase gene, located in a class 1 integron. Of 221 isolates, 77.8% carried bla PER-1-like genes. Eleven different structures of class 1 integrons were detected, and most integrons carried genes mediating resistance to aminoglycosides, rifampin, and chloramphenicol. These findings indicated clonal spread of imipenem-resistant Acinetobacter spp. and wide dissemination of the OXA-23 carbapenemase in China.

The Nor-D3 locus of Triticum tauschii: natural variation and genetic linkage to markers in chromosome 5

Genome ◽  
1991 ◽  
Vol 34 (3) ◽  
pp. 387-395 ◽  
Author(s):  
E. S. Lagudah ◽  
R. Appels ◽  
D. McNeil
Keyword(s):  
Ribosomal Rna ◽  
Intergenic Spacer ◽  
D Genome ◽  
Triticum Tauschii ◽  
Intergenic Spacer Region ◽  
Grain Softness ◽  
High Level ◽  
Rna Genes ◽  
Rdna Polymorphism ◽  
Grain Softness Protein

Variation in the intergenic spacer region of the ribosomal RNA genes (located at the Nor locus) was assayed in a collection of 411 accessions of Triticum tauschii from Turkey, USSR, Iran, Afghanisan, Pakistan, and China. Twenty rDNA genotypes were identified and it was demonstrated that T. tauschii accessions from the USSR and Iran have the highest diversity at the Nor locus. At least four of the rDNA genotypes were demonstrated to be alleles of a single major locus, in segregating F2 progeny analyses. The TaqI restriction fragment associated with rDNA genotype 7 was shown to be the same as the Nor-D3a allele present in all bread wheats (based on chromosome location and length of the intergenic spacer region). This genotype was significantly associated with T. t. ssp. strangulata, previously argued to be the donor of the D genome to hexaploid wheat. The Nor locus showed a high level of recombination with the 5SDna-2 locus, which was also located on chromosome 5D. The Nor locus is placed distal to the 5SDna-2 locus but proximal to the grain softness protein gene (XGsp) on the short arm of chromosome 5D.Key words: D genome, Nor-D3, rDNA polymorphism, chromosomal location.

scholarly journals Increased In Vitro Adherence and On-Farm Persistence of Predominant and Persistent Listeria monocytogenes Strains in the Milking System

2011 ◽  
Vol 77 (11) ◽  
pp. 3676-3684 ◽  
Author(s):  
Alejandra A. Latorre ◽  
Jo Ann S. Van Kessel ◽  
Jeffrey S. Karns ◽  
Michael J. Zurakowski ◽  
Abani K. Pradhan ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Restriction Analysis ◽  
Dairy Farm ◽  
Bulk Tank Milk ◽  
Content Type ◽  
Bulk Tank ◽  
High Level ◽  
On Farm ◽  
Adherence Ability

ABSTRACTDairy farms are a reservoir forListeria monocytogenes, and the reduction of this pathogen at the farm level is important for reducing human exposure. The objectives of this research were to study the diversity ofL. monocytogenesstrains on a single dairy farm, assess strain dynamics within the farm, identify potential sources ofL. monocytogenesin bulk tank milk and milk filters, and assess the adherence abilities of representative strains. A total of 248L. monocytogenesisolates were analyzed by pulsed-field gel electrophoresis (PFGE). Combined AscI and ApaI restriction analysis yielded 40 PFGE types (strains). The most predominant strains were T (28.6%), D (22.6%), and F (14.9%). A high level of heterogeneity of strains among isolates from fecal (Simpson's index of diversity [SID] = 0.96) and environmental (SID = 0.96) samples was observed. A higher homogeneity of strains was observed among isolates from milk filters (SID = 0.71) and bulk tank milk (SID = 0.65). Six of 17L. monocytogenesisolates (35.3%) were classified in anin vitroassay as having a “low adherence ability,” 9 (52.9%) were classified as having a “medium adherence ability,” and 2 (11.8%) were classified as having a “high adherence ability.” TheL. monocytogenesstrains that were predominant and persistent showed significantly better adherence than did strains that were only sporadic, predominant, or persistent (P= 0.0006). Our results suggest that the milking system was exposed to severalL. monocytogenesstrains from different sources. Only 3 strains, however, were successful in persisting within the milking system, suggesting that some strains are more suitable to that particular ecological environment than others.

scholarly journals Differentiation of Moraxella Bovoculi sp. nov. from other Coccoid Moraxellae by the Use of Polymerase Chain Reaction and Restriction Endonuclease Analysis of Amplified DNA

2007 ◽  
Vol 19 (5) ◽  
pp. 532-534 ◽  
Author(s):  
John A. Angelos ◽  
Louise M. Ball
Keyword(s):  
Polymerase Chain Reaction ◽  
Dna Sequence ◽  
Restriction Analysis ◽  
Intergenic Spacer ◽  
Restriction Enzyme Digestion ◽  
Chain Reaction ◽  
Gram Negative ◽  
Intergenic Spacer Region ◽  
Polymerase Chain ◽  
Moraxella Bovoculi

Moraxella oris was historically the only coccoid Moraxella identified in cultures of ocular fluid from cattle with infectious bovine keratoconjunctivitis (IBK) and could be morphologically and biochemically differentiated from Moraxella bovis. Moraxella bovoculi sp. nov. is a recently characterized Moraxella isolated from ulcerated eyes of calves with IBK in northern California in 2002. Like Moraxella ovis, M. bovoculi sp. nov. is a gram-negative coccus/diplococcus. All 18 original isolates of M. bovoculi sp. nov. possessed phenylalanine deaminase (PADase) activity and could therefore be differentiated from M. ovis and M. bovis. During the characterization of 44 additional isolates of hemolytic gram-negative cocci that were cultured from ulcerated eyes of IBK-affected calves, 2 PADase-negative isolates were identified that could not be differentiated biochemically from M. ovis; however, the DNA sequence of the 16S-23S intergenic spacer region (ISR) of the isolates matched the 16S-23S ISR DNA sequence of M. bovoculi sp. nov. To facilitate the identification of PADase-negative moraxellae, a polymerase chain reaction (PCR) coupled with restriction enzyme digestion analysis of amplified DNA was developed. Amplification of the 16S-23S ISR followed by AfaI digestion of amplified DNA could differentiate M. bovoculi sp. nov. from M. ovis and other moraxellae. The DNA sequence analysis of the amplified 16S-23S ISR from the 42 PADase-positive isolates of hemolytic gram-negative cocci indicated that all were M. bovoculi sp. nov. and all possessed an AfaI site. A PCR coupled with restriction analysis of amplified DNA can aid in identifying M. bovoculi sp. nov.

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