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11.
Magnetic separation technology, using magnetic particles, is quick and easy method for sensitive and reliable capture of specific proteins, genetic material and other biomolecules. The technique offers an advantage in terms of subjecting the analyte to very little mechanical stress compared to other methods. Secondly, these methods are non-laborious, cheap and often highly scalable. Moreover, techniques employing magnetism are more amenable to automation and miniaturization. Now that the human genome is sequenced and about 30,000 genes are annotated, the next step is to identify the function of these individual genes, carrying out genotyping studies for allelic variation and SNP analysis, ultimately leading to identification of novel drug targets. In this post-genomic era, technologies based on magnetic separation are becoming an integral part of todays biology laboratory. This article briefly reviews the selected applications of magnetic separation techniques in the field of biotechnology, biomedicine and drug discovery. 相似文献
12.
Side effects of genome structural changes 总被引:2,自引:0,他引:2
Reymond A Henrichsen CN Harewood L Merla G 《Current opinion in genetics & development》2007,17(5):381-386
The first extensive catalog of structural human variation was recently released. It showed that large stretches of genomic DNA that vary considerably in copy number were extremely abundant. Thus it is conceivable that they play a major role in functional variation. Consistently, genomic insertions and deletions were shown to contribute to phenotypic differences by modifying not only the expression levels of genes within the aneuploid segments but also of normal copy-number neighboring genes. In this report, we review the possible mechanisms behind this latter effect. 相似文献
13.
Claus Sibold † Jørgen Henrichsen rea König Christiane Martin Lynda Chalkley Regine Hakenbeck 《Molecular microbiology》1994,12(6):1013-1023
Penicillin-resistant clinical isolates of Streptococcus pneumoniae contain mosaic penicillin-binding protein (PBP) genes that encode PBPs with decreased affinity for β-lactam antibiotics. The mosaic blocks are believed to be the result of gene transfer of homologous PBP genes from related penicillin-resistant species. We have now identified a gene homologous to the pneumococcal PBP2x gene (pbpX) in a penicillin-sensitive Streptococcus oralis isolate M3 from South Africa that diverged by almost 20% from pbpX of penicillin-sensitive pneumococci, and a central sequence block of a mosaic pbpX gene of Streptococcus mitis strain NCTC 10712. In contrast, it differed by only 2-4% of the 1 to 1.5 kb mosaic block in pbpX genes of three genetically unrelated penicillin-resistant S. pneumoniae isolates, two of them representing clones of serotype 6B and 23F, which are prevalent in Spain and are also already found in other countries. With low concentrations of cefotaxime, transformants of the sensitive S. pneumoniae R6 strain could be selected containing pbpX genes from either S. mitis NCTC 10712 or S. oralis M3, demonstrating that genetic exchange can already occur between β-lactam-sensitive species. These data are in agreement with the assumption that PBPs as penicillin-resistance determinants have evolved by the accumulation of point mutations in genes of sensitive commensal species. 相似文献
14.
Kenneth W Cummins Priscila CN Andrade 《Studies on Neotropical Fauna and Environment》2013,48(1):69-89
An analysis conducted at nine stream/river sites in the Atlantic Forest region in the State of Paraná, Brazil used macroinvertebrate functional feeding group (FFG) assessments to evaluate ecological condition of the sites. The FFG approach categorizes qualitative macroinvertebrate collections according to their morphological-behavioral adaptations for food acquisition (e.g. scrapers that harvest non-filamentous, attached algae from stable surfaces in flowing water). FFG ratios were employed as surrogates for stream/river ecosystem attributes: balance between autotrophy and heterotrophy; linkage between riparian inputs of coarse particulate organic matter and in-stream food webs; relative dominance of fine particulate organic matter in transport (suspended load) compared to that deposited in the sediments; and geomorphic stability of the channel. The analyses indicated that all nine sites were heterotrophic, six of the nine carried expected levels of suspended organic load and showed below expected linkage with riparian inputs, and in only two were stable substrates limiting. The implications of the findings and recommendations for further analysis and modifications of the protocol are discussed. 相似文献
15.
Bacterial surface translocation: a survey and a classification 总被引:53,自引:0,他引:53
J Henrichsen 《Bacteriological reviews》1972,36(4):478-503
16.
Background
Modeling of transmembrane domains (TMDs) requires correct prediction of interfacial residues for in-silico modeling and membrane insertion studies. This implies the defining of a target sequence long enough to contain interfacial residues. However, too long sequences induce artifactual polymorphism: within tested modeling methods, the longer the target sequence, the more variable the secondary structure, as though the procedure were stopped before the end of the calculation (which may in fact be unreachable). Moreover, delimitation of these TMDs can produce variable results with sequence based two-dimensional prediction methods, especially for sequences showing polymorphism. To solve this problem, we developed a new modeling procedure using the PepLook method. We scanned the sequences by modeling peptides from the target sequence with a window of 19 residues.Results
Using sequences whose NMR-structures are already known (GpA, EphA1 and Erb2-HER2), we first determined that the hydrophobic to hydrophilic accessible surface area ratio (ASAr) was the best criterion for delimiting the TMD sequence. The length of the helical structure and the Impala method further supported the determination of the TMD limits. This method was applied to the IL-2Rβ and IL-2Rγ TMD sequences of Homo sapiens, Rattus norvegicus, Mus musculus and Bos taurus.Conclusions
We succeeded in reducing the variation in the TMD limits to only 2 residues and in gaining structural information. 相似文献17.
Stanley CK Cheung Li-zhong Liu Lin-lin Lan Qiao-quan Liu Samuel SM Sun Juliana CN Chan Peter CY Tong 《BMC biotechnology》2011,11(1):37
Background
Human insulin-like growth factor-I (hIGF-I) is a growth factor which is highly resemble to insulin. It is essential for cell proliferation and has been proposed for treatment of various endocrine-associated diseases including growth hormone insensitivity syndrome and diabetes mellitus. In the present study, an efficient plant expression system was developed to produce biologically active recombinant hIGF-I (rhIGF-I) in transgenic rice grains. 相似文献18.
Waliza Ansar Sumi Mukhopadhyay SK. Hasan Habib Shyamasree Basu Bibhuti Saha Asish Kumar Sen CN. Mandal Chitra Mandal 《Glycoconjugate journal》2009,26(9):1151-1169
Human C-reactive protein (CRP), as a mediator of innate immunity, removed damaged cells by activating the classical complement
pathway. Previous studies have successfully demonstrated that CRPs are differentially induced as glycosylated molecular variants
in certain pathological conditions. Affinity-purified CRPs from two most prevalent diseases in India viz. tuberculosis (TB) and visceral leishmaniasis (VL) have differential glycosylation in their sugar composition and linkages. As anemia is a common manifestation in TB and
VL, we assessed the contributory role of glycosylated CRPs to influence hemolysis via CRP-complement-pathway as compared to
healthy control subjects. Accordingly, the specific binding of glycosylated CRPs with erythrocytes was established by flow-cytometry
and ELISA. Significantly, deglycosylated CRPs showed a 7–8-fold reduced binding with erythrocytes confirming the role of glycosylated
moieties. Scatchard analysis revealed striking differences in the apparent binding constants (104–105 M−1) and number of binding sites (106–107sites/erythrocyte) for CRP on patients’ erythrocytes as compared to normal. Western blotting along with immunoprecipitation
analysis revealed the presence of distinct molecular determinants on TB and VL erythrocytes specific to disease-associated
CRP. Increased fragility, hydrophobicity and decreased rigidity of diseased-erythrocytes upon binding with glycosylated CRP
suggested membrane damage. Finally, the erythrocyte-CRP binding was shown to activate the CRP-complement-cascade causing hemolysis,
even at physiological concentration of CRP (10 μg/ml). Thus, it may be postulated that CRP have a protective role towards
the clearance of damaged-erythrocytes in these two diseases. 相似文献
19.
Toh M Moffitt MC Henrichsen L Raftery M Barrow K Cox JM Marquis CP Neilan BA 《Journal of applied microbiology》2004,97(5):992-1000
AIMS: To determine if cereulide, the emetic toxin produced by Bacillus cereus, is produced by a nonribosomal peptide synthetase (NRPS). METHODS AND RESULTS: NC Y, an emetic strain of Bacillus cereus, was examined for a NRPS gene using PCR with primers recognizing a fragment of a NRPS gene from the cyanobacterium Microcystis. The amplicon was sequenced and compared with other gene sequences using BLAST analysis, which showed that the amplicon from strain NC Y was similar in sequence to peptide synthetase genes in other micro-organisms, including Bacillus subtilis and B. brevis, while no such sequence was found in the complete genome sequence of a nonemetic strain of B. cereus. Specific PCR primers were then designed and used to screen 40 B. cereus isolates previously implicated in outbreaks of foodborne illness. The isolates were also screened for toxin production using the MTT cell cytotoxicity assay. PCR and MTT assay screening of the B. cereus isolates revealed a high correlation between the presence of the NRPS gene and cereulide production. CONCLUSIONS: The results indicate that cereulide is produced by a NRPS complex. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study to provide evidence identifying the mechanism of production of cereulide, the emetic toxin of B. cereus. The PCR primers developed in the study allow determination of the potential for cereulide production among isolates of B. cereus. 相似文献
20.
A DOS-compatible model for use on personal computers has been constructed for teaching in parasite epidemiology. The program is based on the Macdonald model of schistosome dynamics and enables simulation of the effect of a control campaign on a human worm load by reducing four transmission factors in the parasite life-cycle: (1) egg contamination, (2) snail lifetime, (3) exposure to cercariae and (4) adult worm lifetime. 相似文献