SEARCH · PubMed Health

Results for “Characterization”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39Linked to original sources

PubMed2000

Characterization of steroid hormone sensitivity in human breast cancers maintained ex vivo under organotypical culture conditions.

PURPOSE: The methodology we propose combines the immunohistochemical determination of the oestrogen and progesterone receptors (ER and PgR) with the characterization of the oestradiol- and progesterone-induced influence on cell proliferation in breast cancers in order to characterize their steroid hormone sensitivity at both the "static" and "dynamic" level. METHODS: ER and PgR have been immunohistochemically quantified by means of computer-assisted microscopy. Cell proliferation has been determined by means of tritiated thymidine autoradiography in tumour samples maintained in vitro as organotypic cultures. A series of 14 patients was investigated. RESULTS: Of the 14 breast cancers under study, one with an unequivocally "very ER-rich"/"very PgR-rich" immunohistochemical phenotype totally failed to exhibit any modification in its cell proliferation level after both oestradiol and progesterone stimulation. Two cases definitively associated with an "ER-poor"/"PgR-poor" immunohistochemical phenotype nevertheless responded noticeably to the dynamic stimulation of their cell proliferation by oestradiol and progesterone. While our series of cases covers 14 patients only, it suffices to demonstrate the limits of ER and PgR determination in characterizing steroid hormone sensitivity in breast cancer. DISCUSSION: The present work therefore presents an in vitro approach to test growth regulation of human breast cancer by steroid hormones. The clinical value of the present approach should be further determined by showing that steroid hormone-induced modifications in cell proliferation level are actually associated with clinical response.

Aged↗

PubMed1998

Characterization of Giardia duodenalis by polymerase-chain-reaction fingerprinting.

The development of a polymerase chain reaction (PCR) based fingerprinting method for the characterization of Giardia duodenalis isolates is described. The method uses three different PCRs; one is specific for the A ("Polish") major group of G. duodenalis isolates, another is specific for the B ("Belgian") group of isolates; and one amplifies a fragment of the glutamate dehydrogenase gene present in all G. duodenalis isolates. The PCRs perform highly sensitively on DNA from cultured trophozoites. Isolates were further characterized by restriction-fragment-length polymorphism (RFLP) analysis of the PCR products. In this way, representative isolates from the A and B groups could be grouped together into a number of subgroups. The stability of the genotypes with time and the reproducibility of the two methods were tested on cloned and subcloned lines from a number of isolates and proved to be highly satisfactory. The PCR/RFLP method was evaluated on cysts derived from a number of human patients. It is concluded that the PCR fingerprinting method described in this paper provides a reliable characterization method for Giardia isolates and has the potential to be used as a direct method of typing G. duodenalis cysts from feces.

Adolescent↗

PubMed2004

Scd1ab-Xyk: a new asebia allele characterized by a CCC trinucleotide insertion in exon 5 of the stearoyl-CoA desaturase 1 gene in mouse.

We describe here a spontaneous, autosomal recessive mutant mouse suffering from skin and hair defects, which arose in the outbred Kunming strain. By haplotype analysis and direct sequencing of PCR products, we show that this mutation is a new allele of the asebia locus with a naturally occurring mutation in the Scd1 gene (a CCC insertion at nucleotide position 835 in exon 5), which codes for stearoyl-CoA desaturase 1. This mutation introduces an extra proline residue at position 279 in the Scd1 protein. The mutant mice, originally designated km/km but now assigned the name Scd1ab-Xyk (hereafter abbreviated as abXyk/abXyk), have a similar gross and histological phenotype to that reported for previously characterized allelic asebia mutations (Scd1ab, Scd1abJ, Scd1ab2J, and Scd1tm1Ntam). Histological analysis showed they were also characterized by hypoplasic sebaceous glands and abnormal hair follicles. In a cross between Kunming- abXyk/abXyk and ABJ/Le-abJ/abJ mice, all the progeny showed the same phenotype, indicating that the two mutations were non-complementing and therefore allelic. Comparisons with the other four allelic mutants indicate that the Scd1ab-Xyk mutation causes the mildest change in Scd1 function. This new mouse mutant is a good model not only for the study of scarring alopecias in humans, which are characterized by hypoplasic sebaceous glands, but also for studying the structure and function of the Scd1 protein.

Alleles↗

PubMed1999

Molecular characterization of waxy mutations in wheat.

To date, few mutations in wheat have been characterized at the molecular level. In this study, the mutations in the three waxy alleles in waxy wheat (Wx-A1h, Wx-B1b and Wx-D1b) were characterized, and waxy gene expression was compared in several wheat lines, including hexaploid and tetraploid waxy lines of wheat. Southern analysis showed that the Wx-B1b allele had sustained a deletion which included the entire coding region of the Wx-B1 gene. DNA homologous to waxy gene sequences was still present in the Wx-A1b and Wx-D1b alleles of the hexaploid waxy mutant. Transcripts of waxy alleles were also detected in both hexaploid and tetraploid mutants at 10 days post-anthesis, but the transcript level was dramatically reduced compared to that found in non-waxy lines. Isolation of cDNAs showed that transcripts were produced by both the Wx-A1b and Wx-D1b alleles. A 23-bp deletion sustained by the Wx-A1b allele at an exon-intron junction results in the use of a cryptic splice site during mRNA processing. The deduced translation product encoded by the Wx-A1b cDNA lacks 39 amino acids, including the putative ADP-glucose binding site and a portion of the transit peptide. The C-terminal region of the deduced protein encoded by the Wx-D1b cDNA lacks the last 30 amino acids. Comparison of the genomic sequences of the null and wild-type Wx-D1 alleles indicated that 588 bp were deleted in the Wx-D1b mutation, and that the last 261 bp of the Wx-D1b cDNA originated from the normally non-transcribed 3' flanking region. Like several deletion mutations characterized in other plant species, both Wx-A1b and Wx-D1b alleles contain small DNA insertions, or filler DNA, between the deletion end-points.

Alleles↗

PubMed2001

A new multicolor-FISH approach for the characterization of marker chromosomes: centromere-specific multicolor-FISH (cenM-FISH).

Centromere-specific multi-color FISH (cenM-FISH) is a new multicolor FISH technique that allows the simultaneous characterization of all human centromeres by using labeled centromeric satellite DNA as probes. This approach allows the rapid identification of all human centromeres by their individual pseudo-coloring in one single step and is therefore a powerful tool in molecular cytogenetics. CenM-FISH fills a gap in multicolor karyotyping using WCP probes and distinguishes all centromeric regions apart from the evolutionary highly conserved regions on the chromosomes 13 and 21. The usefulness of the cenM-FISH technique for the characterization of small supernumerary marker chromosomes with no (or nearly no) euchromatin and restricted amounts of available sample material is demonstrated in prenatal, postnatal, and tumor cytogenetic cases. In addition, rarely described markers with the involvement of heterochromatic material inserted into homogeneously staining regions could be identified and characterized by using the cenM-FISH technique.

Centromere↗

PubMed2002

Differentiation of human alveolar epithelial cells in primary culture: morphological characterization and synthesis of caveolin-1 and surfactant protein-C.

Human alveolar type II cells were isolated from lung tissue and cultured for several days. The morphology of cells was investigated at different time points postseeding and the synthesis of alveolar cell-type specific proteins was analyzed using different methods. The rationale of the study was to characterize a primary cell culture of human alveolar cells for the development of an in vitro model studying pulmonary drug delivery. In vitro test systems based on human cells are attracting increasing interest as important alternatives to animal-derived models because possible interspecies differences in alveolar cell biology and transport mechanisms cannot be excluded. In our study, both morphological characterization and marker protein synthesis of human alveolar cells in culture indicate the differentiation of isolated alveolar type II cells into epithelial monolayers consisting of alveolar type I-like and alveolar type II-like cells, which corresponds to the composition of the alveolar epithelium of the donor tissue. By using flow cytometry, immunofluorescence, immunoblotting and reverse transcriptase polymerase chain reaction (RT-PCR), we observed a shift in the synthesis of important marker proteins. Early cultures were characterized by low caveolin-1 and high Sp-C levels. In comparison, the protein biosynthesis of alveolar cells switched with time of culture to high caveolin-1 and low Sp-C levels. Based on the similarity between human alveolar epithelium and the development of our primary alveolar cell culture, we suggest that the culture may serve as a suitable model to study epithelial transport or cell biological processes in human alveolar cells.

Antibodies↗

PubMed1998

Ultrastructural characterization of interstitial cells of Cajal in the rat small intestine using control and Ws/Ws mutant rats.

Interstitial cells in the myenteric plexus and the deep muscular plexus of the small intestine of the c-kit mutant rats (Ws/Ws) and their normal siblings (+/+) were studied. c-Kit immunoreactivity was detected in two regions corresponding to the myenteric plexus and the deep muscular plexus in the jejunum of +/+ rats, while no immunoreactivity was detected in Ws/Ws rats. Using electron microscopy, two types of gap junction-forming interstitial cells were found in association with the myenteric plexus in +/+ rats: one type characterized by a typical fibroblastic ultrastructure, and the other characterized by numerous mitochondria and less electron-dense cytoplasm. Since the latter were greatly reduced in Ws/Ws rats, it was suggested that these cells correspond to c-kit-expressing cells, i.e. interstitial cells of Cajal in the myenteric plexus region. In contrast, two types of interstitial cells in the region of the deep muscular plexus were observed with no difference between +/+ and Ws/Ws rats. Probable interstitial cells of Cajal in this region were characterized by a basal lamina and numerous caveolae as well as large gap junctions that interconnect with each other and with the smooth muscle cells. We concluded that interstitial cells of Cajal in the rat intestine are heterogeneous in ultrastructure, c-kit dependency in the cell maturation, and functional role.

Animals↗

PubMed1999

Localization and characterization of intracerebral cavernous angiomas by intra-operative high-resolution colour-duplex-sonography.

The aim of this prospective study was to evaluate the reliability of high-resolution Colour-Duplex-Sonography (= CDS) in intra-operative localization, guiding and characterization of intracerebral cavernous angiomas (= CA). During a time period from 5/93 to 12/96 a total of 26 patients with 21 supratentorial and 5 infratentorial CA (15 of them deep-seated) were examined intra-operatively by CDS. The study focussed on 1. sonographic characterization, 2. localization in relationship to anatomical landmarks, 3. navigation, 4. correlation of sonographic to magnetic resonance imaging (= MRI), intra-arterial angiography (= DSA) and histological results and 5. control of complete resection. All CA appeared sonographically as hyperechoic lesions without flow-signals in Colour-mode. Imaging of anatomical landmarks as cerebral sulci, brain stem, insular cistern, falx, ventricles and vessels could be used for precise localization and successful guiding to 15 deep-seated lesions. The correlation of the size between MRI and CDS was excellent (1.4 mm mean difference, range from 0 to 5 mm). All 4 associated venous anomalies, as verified by pre-operative DSA, could be visualized and identified by CDS. The completeness of exstirpation was controlled sonographically in 14 cases and confirmed by MRI (= 10) and CT (= 4). This study provides the first comprehensive intra-operative characterization of CAs by CDS and correlation to MRI and DSA. Furthermore it demonstrates the reliability of CDS for intra-operative localization and guiding as well as its potential to control the complete exstirpation.

Adolescent↗

PubMed2005

Mixed-ligand complexes of ruthenium(II) containing new photoactive or electroactive ligands: synthesis, spectral characterization and DNA interactions.

Mixed-ligand ruthenium(II) complexes of three photoactive ligands, viz., (E)-1-[2-(4-methyl-2-pyridyl)-4-pyridyl]-2-(1-naphthyl)-1-ethene (mppne), (E)-1-(9-anthryl)-2-[2-(4-methyl-2-pyridyl)-4-pyridyl]-1-ethene (mppae) and (E)-1-[2-(4-methyl-2-pyridyl)-4-pyridyl]-2-(1-pyrenyl)-1-ethene (mpppe), in which a 2,2'-bipyridyl unit is linked via an ethylinic linkage to either a naphthalene, an anthracene or a pyrene chromophore and three electroactive ligands, viz., 4-(4-pyridyl)-1,2-benzenediol (catpy), 5,6-dihydroxy-1,10-phenanthroline (catphen) and 1,2-benzenediol (cat), were synthesized in good to moderate yields. Complexes [Ru(bpy)(2)(mppne)](2+) (bpy is 2, 2'-bipyridyl), [Ru(bpy)(2)(mppae)](2+), [Ru(bpy)(2)(mpppe)](2+), [Ru(bpy)(2)(sq-py)](+), [Ru(bpy)(2)(sq-phen)](+) and [Ru(phen)(2)(bsq)](+) (phen is 1,10-phenanthroline) were fully characterized by elemental analysis, IR, (1)H NMR, fast-atom bombardment or electron-impact mass, UV-vis and cyclic voltammetric methods. In the latter three complexes, the ligands catpy, catphen and cat are actually bound to the metal center as the corresponding semiquinone species, viz., 4-(4-pyridyl)-1,2-benzenedioleto(+I) (sq-py), 1,10-phenanthroline-5,6-dioleto(+I) (sq-phen) and 1,2-benzenedioleto(+I) (bsq), thus making the overall charge of the complexes formally equal to + 1 in each case. These three complexes are electron paramagnetic resonance active and exhibit an intense absorption band between 941 and 958 nm owing to metal-to-ligand charge transfer (MLCT, d (Ru)-->pi*(sq)) transitions. The other three ruthenium(II) complexes containing three photoactive ligands, mppne, mppae and mpppe, exhibit MLCT (d (Ru)-->pi*(bpy) ) bands in the 454-461-nm region and are diamagnetic. These can be characterized by the (1)H NMR method. [Ru(bpy)(2)(mppne)](2+), [Ru(bpy)(2)(mppae)](2+) and [Ru(bpy)(2)(mpppe)](2+) exhibit redox waves corresponding to the Ru(III)/Ru(II) couple along with the expected ligand (bpy and substituted bpy) based ones in their cyclic and differential pulse voltammograms (CH(3)CN, 0.1 M tetrabutylammonium hexafluorophosphate)-corresponding voltammograms of [Ru(bpy)(2)(sq-py)](+), [Ru(bpy)(2)(sq-phen)](+) and [Ru(phen)(2)(bsq)](+) are mainly characterized by waves corresponding to the quinone/semiquinone (q/sq) and semiquinone/1,2-diol (sq/cat) redox processes. The results of absorption and fluorescence titration as well as thermal denaturation studies reveal that [Ru(bpy)(2)(mppne)](2+) and [Ru(bpy)(2)(mppae)](2+) are moderate-to-strong binders of calf thymus DNA with binding constants ranging from 10(5) to 10(6) M(-1). Under the identical conditions of drug and light dose, the DNA (supercoiled pBR 322) photocleavage activities of these two complexes follow the order:[Ru(bpy)(2)(mppne)](2+)>[Ru(bpy)(2)(mppae)](2+), although the emission quantum yields follow the reverse order. The other ruthenium(II) complexes containing the semiquinone-based ligands are found to be nonluminescent and inefficient photocleavage agents of DNA. However, experiments shows that [Ru(bpy)(2)(sq)](+)-based complexes oxidize the sugar unit and could be used as mild oxidants for the sugar moiety of DNA. Possible explanations for these observations are presented.

DNA↗

PubMed2003

Molecular and serological characterization of group a rotavirus isolates obtained from hospitalized children in Goiânia, Brazil, 1998-2000.

Fecal samples positive for rotavirus group A ( n=120) were analyzed by enzyme immunoassay-monoclonal antibody (EIA-MAb) serotyping and/or reverse transcription/multiplex polymerase chain reaction (PCR) amplification to determine the prevalence of the [P] and G genotypes. The most prevalent G genotype/serotype detected was G1 (76.7%), followed by G2 (5.0%). Six samples were characterized as G9 by multiplex PCR, and one sample was characterized as G3 by EIA-MAb. The combinations of [P] and G genotypes found were P[8] and G1 (20.8%), P[6] and G1 (10.8%), P[6] and G9 (4.2%), P[8] and G2 (1.7%), and P[6] and G2 (0.8%). The diversity of rotavirus group A [P] and G genotypes/serotypes reinforces the need for continuous characterization of rotaviruses circulating in populations in Brazil.

Brazil↗

PubMed2000

Characterization of Satellite DNA Sequences from the Commercially Important Marine Rotifers Brachionus rotundiformis and Brachionus plicatilis.

This study was initiated to search for species-specific and strain-specific satellite DNA sequences for which oligonucleotide primers could be designed to differentiate between various commercially important strains of the marine monogonont rotifers Brachionus rotundiformis and Brachionus plicatilis. Two unrelated, highly reiterated satellite sequences were cloned and characterized. The eight sequenced monomers from B. rotundiformis and six from B. plicatilis had low intrarepeat variability and were similar in their overall lengths, A + T compositions, and high degrees of repeated motif substructure. However, hybridizations to 19 representative strains, sequence characterizations, and GenBank searches indicated that these two satellites are morphotype-specific and population-specific, respectively, and share little homology to each other or to other characterized sequences in the database. Primer pairs designed for the B. rotundiformis satellite confirmed hybridization specificities on polymerase chain reaction and could serve as a useful molecular diagnostic tool to identify strains belonging to the SS morphotype, which are gaining widespread usage as first feeds for marine fish in commercial production.

Journal Article↗

PubMed2005

Heterogeneity of radiation induced apoptosis in Ewing Tumor cell lines characterized on a single cell level.

The objective of this study was to investigate heterogeneity of radiation induced apoptosis on a single cell level. Two Ewing tumor cell lines were characterized in vitro before and 24 and 72 h after radiation with 5 Gy by multiparametric flow cytometry. Annexin V, 7-AAD and fluorescence conjugated antibodies that were directed against HLA-ABC, CD11a and CD62L were used. Based on these markers radiation induced apoptosis was quantified, multiple apoptotic subpopulations were identified and a characteristic individual apoptotic profile was characterized. The characterization of HLA-ABC, CD11a and CD62L was informative to detect subpopulations of apoptotic cells. The observed heterogeneity and the identification of multiple apoptotic subpopulations reflect the complexity and diversity of biology of radiation induced cell death. This might be an indication for co-existing apoptotic pathways or it might represent sequential steps of the apoptotic cascade.

Apoptosis↗

PubMed2006

Characterization of the highly variable cry gene regions of Bacillus thuringiensis strain ly4a3 by PCR-SSCP profiling and sequencing.

Characterization of cry gene contents can help to predict the insecticidal activities of Bacillus thuringiensis isolates and in the searching of new cry genes. PCR-Single-strand conformation polymorphism (SSCP) profiling and sequencing of the highly variable cry gene regions were used to characterize cry gene content of B. thuringiensis strain ly4a3. The highly variable regions with about 1100 bp in sizes were amplified using a degenerate primer pair for cry genes, OL2(d) and OL5(r). A library of the PCR product was constructed, and all white colonies were subjected to PCR using another degenerate primer pair for cry genes, OL3(d) and OL5(r), with products about 250 bp in sizes. Two different profiles were observed based on SSCP profiling for the PCR products. The cry genes in the two corresponding colonies were sequenced and their deduced amino acids showed high identities to Cry1Ab (84.5% approximately 98.4%) and Cry1I (88.78% approximately 98.4%), respectively. This method allows the quick characterization of cry gene content of B. thuringiensis isolates and the detection of new cry genes.

Bacillus thuringiensis↗

PubMed2005

Characterization of exocytotic events from single PC12 cells: amperometric studies in native PC12h, DA-loaded PC12h and bovine adrenal chromaffin cells.

Exocytotic events from rat pheochromocytoma (PC12) cells were characterized by amperometric analysis. For single-cell amperometric recordings, PC12h cells cultured onto poly-L-lysine corted glass-base dish were incubated with 1 mM dopamine (DA) for 60 min. Amperometric recordings, with a carbon fiber microelectrode (5 mum diameter), of catecholamine release from the individual cells were conducted under an inverted microscope at 25 degrees C. To characterize a single exocytotic event that is detected as a single spike current, the spike number, spike parameters (rise time, middle width and area) and spike shape were analyzed. Exposure of DA-loaded PC12h cells to 60 mM KCl (1000 hps) for 5 min and for 4 s evoked a train of events with the event number of 114+/-19 (spikes/response for 5 min) and 12+/-3 (spikes/response for 15 s), respectively. We observed distinctive kinetics in the events (rise time=0.83+/-0.19 ms, middle width=2.89+/-0.62 ms, area=62+/-7.6 fC and the spikes with a "foot"=15.4+/-2.7% of total spikes). The number and mean height of the events were 3- to 4-fold higher than that in DA-unloaded cells, and the values of rise time and middle width in DA-loaded PC12h cells were approx. 5- and 10-fold less than those observed in cultured adrenal chromaffin cells. The successful application of amperometry to monitor DA released from secretory vesicles in DA-loaded PC12h cell suggest that this technique is applicable to characterize exocytotic events in neurons.

Action Potentials↗

PubMed2005

Microstructural and in vitro characterization of SiO2-Na2O-CaO-MgO glass-ceramic bioactive scaffolds for bone substitutes.

In the present research work, the preparation and characterization of bioactive glass-ceramic scaffolds for bone substitutes are described. The scaffolds were prepared by starch consolidation of bioactive glass powders belonging to the SiO2-Na2O-CaO-MgO system using three different organic starches (corn, potatoes and rice) as reported in a previous screening process. The scaffolds, characterized by scanning electron microscopy, showed a porous structure with highly interconnected pores. The pores sizes assessed by mercury intrusion porosimetry put in evidence the presence of pores of 50-100 microm. The structure of the scaffolds was investigated by X-ray diffraction and revealed the glass-ceramic nature of the obtained material. The mechanical properties of the scaffolds were evaluated by means of compressive tests on cubic samples and the obtained results demonstrated their good mechanical strength. The in vitro bioactivity of the scaffolds was tested by soaking them in a simulated body fluid (SBF) and by subsequently characterizing the soaked surfaces by SEM, EDS and X-ray diffraction. Good in vitro bioactivity was found for the starting glass and for the obtained scaffolds. Moreover, the scaffold bioresorption, tested by measuring the samples weight loss in SBF at different periods of time, showed a partial resorption of the scaffolds. Cell culture testing of the three different scaffolds indicated no differences in cell number and in alkaline phosphatase activity; the morphology of the osteoblasts showed good spreading, comparable to bulk material which was used as the control.

Body Fluids↗

PubMed2006

Expression and characterization of wild-type TFPI and the [P151L]TFPI mutant in insect cells.

Tissue factor pathway inhibitor (TFPI) is a multivalent Kunitz-type serine proteinase inhibitor that plays a central role in the extrinsic pathway of blood coagulation. In earlier studies we could identify the [P151L]TFPI mutant, and we could also demonstrate that heterozygous carriers of this mutant show a nine-fold increased risk for deep venous thrombosis (DVT). To express greater amounts of both proteins and to enable their characterization, we expressed wild-type TFPI as well as [P151L]TFPI in High Five insect cells with expression rates of up to 215 ng/ml for wild-type TFPI and 214 ng/ml for [P151L]TFPI. The specific inhibitory activities for the recombinant proteins were determined as 11.3 and 11.5 mU/ng, respectively. Both proteins were detected via Western blot analysis and ELISA. The recombinant proteins' inhibitory activities were characterized by a chromogenic assay and by the determination of a modified activated thromboplastin time (aPTT) in which both of them proved to be inhibitorily active. We also examined both recombinant proteins' binding properties to glycoproteins, glycosaminoglycans, lipoproteins and tissue factor. Our results show that we have developed an efficient model system for the recombinant expression of inhibitorily active wild-type TFPI as well as [P151L]TFPI in insect cells, and we were able to characterize both proteins' inhibitory properties by determination of their influence on the aPTT and also their binding properties. Although both recombinant proteins did not show a significant difference in their effect on the aPTT, their binding properties differed significantly between the wild type and mutant protein.

Animals↗

PubMed2005

Structural characterization of a recombinant monoclonal antibody by electrospray time-of-flight mass spectrometry.

PURPOSE: The aim of this study was to perform structural characterization of a recombinant monoclonal antibody (MAb), huN901, by electrospray time-of-flight mass spectrometry (ESI-TOFMS) using both "top-down" and "bottom-up" approaches. METHODS: In the top-down approach, the molecular masses of the deglycosylated huN901 and the light and heavy chains of the antibody were measured by direct infusion MS and liquid chromatography-mass spectrometry (LC-MS). In the bottom-up approach, trypsin and Asp-N protease were used to digest the separated, reduced and alkylated light and heavy chains followed by LC-MS analysis of the digests. RESULTS: The primary structure and post-translational modifications of huN901 were characterized by both top-down and bottom-up MS approaches. Modifications of N-terminal pyroglutamate formation, cleavage of C-terminal lysine, glycosylation, and deamidation were identified in the antibody heavy chain by both protein mass measurement and peptide mapping. No modifications were found in the complementarity determining regions (CDRs) of both chains. Both trypsin and Asp-N protease digestion had an average sequence recovery of 97%, and generated complimentary mapping results with complete sequence recovery. CONCLUSIONS: ESI-TOFMS is a superior tool to characterize MAb and other complex protein pharmaceuticals.

Alkylation↗

PubMed2004

Recent progress in the characterization of molecular determinants in the Xanthomonas axonopodis pv. manihotis-cassava interaction.

Cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis (Xam), is a widespread disease that affects cassava (Manihot esculenta Crantz). Studies on the pathogen population structure, pathogen diagnosis, identification and expression of plant genes involved in resistance have been carried out. Different molecular techniques were developed to assess the genetic diversity among the Xampopulations. Characterization of Xam population dynamics over time had enable us to determine the different factors that are associated with resistance breakdown and those that influence the genetic structure or virulence phenotypes of the pathogen's population. Methods for detecting the pathogen in vegetative planting materials and true seeds were developed and contributed to reduce the impact of the disease. To better understand the genetics of resistance a quantitative trait loci (QTLs) approach was developed. Using a PCR-based strategy with degenerate primers we isolated two resistance gene candidates in cassava. We also characterized a region of a chromosome rich in R-gene like sequence. In this review we also report the main results obtained by transcript profiling methodologies, cDNA-AFLP and ESTs developed by the authors to characterize the genes involved in disease resistance. All together these techniques allowed the identification of molecular markers either associated to CBB resistance or that may represent putative genes involved in disease resistance. This article reviews current knowledge on the molecular cassava-Xam interactions.

Chromosome Mapping↗