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981.
Kim D Kim SN Baik KS Park SC Lim CH Kim JO Shin TS Oh MJ Seong CN 《Journal of microbiology (Seoul, Korea)》2011,49(1):141-145
A metagenomic fosmid library was constructed using genomic DNA isolated from abalone intestine. Screening of a library of
3,840 clones revealed a 36 kb insert of a cellulase positive clone (pAMHElO). A shotgun clone library was constructed using
the positive clone (pAMHElO) and further screening of 3,840 shotgun clones with an approximately 5 kb insert size using a
Congo red overlay revealed only one cellulase positive clone (pAMHL9). The pAMHL9 consisted of a 5,293-bp DNA sequence and
three open reading frames (ORFs). Among the three ORFs, cellulase activity was only shown in the recombinant protein (CelAMll)
coded by ORF3, which showed 100% identity with outer membrane protein A from Vibrio alginolyticus 12G01, but no significant sequence homology to known cellulases. The expressed protein (CelAMll) has a molecular weight of
approximately 37 kDa and the highest CMC hydrolysis activity was observed at pH 7.0 and 37°C. The carboxymethyl cellulase
activity was determined by zymogram active staining and different degraded product profiles for CelAMll were obtained when
cellotetraose and cellopentaose were used as the substrates, while no substrate hydrolysis was observed on oligosaccharides
such as cellobiose and cellotriose. 相似文献
982.
Shivaji S Pratibha MS Sailaja B Hara Kishore K Singh AK Begum Z Anarasi U Prabagaran SR Reddy GS Srinivas TN 《Extremophiles : life under extreme conditions》2011,15(1):1-22
Three 16S rRNA gene clone libraries (P1L, P4L and P8L) were constructed using three soil samples (P1S, P4S and P8S) collected
near Pindari glacier, Himalayas. The three libraries yielded a total of 703 clones. Actinobacteria, Firmicutes and Proteobacteria were common to the three libraries. In addition to the above P1L and P8L shared the phyla Acidobacteria, Bacteroidetes, Gemmatimonadetes and Planctomycetes. Phyla Chlamydiae, Chlorobi, Chloroflexi, Dictyoglomi, Fibrobacteres, Nitrospirae, Verrucomicrobia, candidate division SPAM and candidate TM7s TM7a phylum were present only in P1L. Rarefaction analysis indicated that the
bacterial diversity in P4S and P8S soil samples was representative of the sample. Principal component analysis (PCA) revealed
that P1S and P8S were different from P4S soil sample. PCA also indicated that arsenic content, pH, Cr and altitude influence
the observed differences in the percentage of specific OTUs in the three 16S rRNA gene clone libraries. The observed bacterial
diversity was similar to that observed for other Himalayan and non-polar cold habitats. A total of 40 strains of bacteria
were isolated from the above three soil samples and based on the morphology 20 bacterial strains were selected for further
characterization. The 20 bacteria belonged to 12 different genera. All the isolates were psychro-, halo- and alkalitolerant.
Amylase and urease activities were detected in majority of the strains but lipase and protease activities were not detected.
Long chain, saturated, unsaturated and branched fatty acids were predominant in the psychrotolerant bacteria. 相似文献
983.
Ingo Aldag Ulrike Bockau Jan Rossdorf Sven Laarmann Willem Raaben Lutz Herrmann Thomas Weide Marcus WW Hartmann 《BMC biotechnology》2011,11(1):11
Background
Tetrahymena thermophila possesses many attributes that render it an attractive host for the expression of recombinant proteins. Surface proteins from the parasites Ichthyophthirius multifiliis and Plasmodium falciparum and avian influenza virus antigen H5N1 were displayed on the cell membrane of this ciliate. Furthermore, it has been demonstrated that T. thermophila is also able to produce a functional human DNase I. The present study investigates the heterologous expression of the functional human intestinal alkaline phosphatase (hiAP) using T. thermophila and thereby presents a powerful tool for the optimization of the ciliate-based expression system. 相似文献984.
985.
Kyoung Ah Kang Rui Zhang Mei Jing Piao Min Jeong Park Ae Ran Kwon Bum Joon Kim Ho Jin You Myung Hee Chung Jin Won Hyun 《Biotechnology and Bioprocess Engineering》2007,12(2):114-120
8-Hydroxydeoxyguanosine (oh8dG) treatment induced senescence-like changes in KG-1 cells, a human acute myelocytic leukemia cell line. The oh8dG-treated cells stained positive for senescence associated β-galactosidase (SA-β-galactosidase) and had enlarged cell shape,
both of which are senescence indexes. The oh8dG-treated cells were also cell growth inhibited and arrested at G1 in the cell cycle. The accumulation of cdk (cyclin dependent kinase) inhibitors, such as p16, p21, and p27, also implies
that cellular senescence was induced in oh8dG-treated cells. However, these changes were not accompanied by cell differentiation or telomerase activity. Taken together,
we conclude that oh8dG treatment of KG-1 cells induces cellular senescence. 相似文献
986.
A simple and precise method for chiral separation of tryptophan enantiomers using high performance liquid chromatography with
aligand exchange mobile phase was developed. Chiral separation was performed on a conventional C18 column, using a mobile phase that consisted of a water-methanol solution (88∶12, v/v) containing 10 mmol/Ll-leucine and 5 mmol/L copper sulfate as a chiral ligand additive at a flow rate of 1.0 mL/min. This method allowed baseline
separation of two enantiomers with a resolution of 1.84 in less than 30 min. The effect of various conditions, including concentration,
type of ligand, organic modifier, pH, flow rate, and temperature, on enantioseparation were evaluated and chiral recognition
mechanisms were investigated. Thermodynamic data (ΔΔH and ΔΔS) obtained by van't Hoff plots revealed that enantioseparation is an enthalpy-controlled process. 相似文献
987.
988.
Background
DING proteins constitute a conserved and broadly distributed set of proteins found in bacteria, fungi, plants and animals (including humans). Characterization of DING proteins from animal and plant tissues indicated ligand-binding ability suggesting a role for DING proteins in cell signaling and biomineralization. Surprisingly, the genes encoding DING proteins in eukaryotes have not been identified in the eukaryotic genome or EST databases. Recent discovery of a DING homologue (named Psp here) in the genome of Pseudomonas fluorescens SBW25 provided a unique opportunity to investigate the physiological roles of DING proteins. P. fluorescens SBW25 is a model bacterium that can efficiently colonize plant surfaces and enhance plant health. In this report we genetically characterize Psp with a focus on conditions under which psp is expressed and the protein exported. 相似文献989.
Ana Martín Marta Herránz María Jesús Ruiz Serrano Emilio Bouza Darío García de Viedma 《BMC microbiology》2007,7(1):73
Background
The application of molecular tools to the analysis of tuberculosis has revealed examples of clonal complexity, such as exogenous reinfection, coinfection, microevolution or compartmentalization. The detection of clonal heterogeneity by standard genotyping approaches is laborious and often requires expertise. This restricts the rapid availability of Mycobacterium tuberculosis (MTB) genotypes for clinical or therapeutic decision-making. A new PCR-based technique, MIRU-VNTR, has made it possible to genotype MTB in a time frame close to real-time fingerprinting. Our purpose was to evaluate the capacity of this technique to provide clinicians with a rapid discrimination between reactivation and exogenous reinfection and whether MIRU-VNTR makes it possible to obtain data directly from stored MTB isolates from recurrent episodes. 相似文献990.