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At least 667 records · Page 37Linked to original sources

PubMed1998

Kinematics of aquatic and terrestrial prey capture in Terrapene carolina, with implications for the evolution of feeding in cryptodire turtles.

Studies of aquatic prey capture in vertebrates have demonstrated remarkable convergence in kinematics between diverse vertebrate taxa. When feeding in water, most vertebrates employ large-amplitude hyoid depression to expand the oral cavity and suck in water along with the prey. In contrast, vertebrates feeding on land exhibit little or no hyoid depression. In this study we compared the kinematics of terrestrial and aquatic prey capture within one species of turtle, Terrapene carolina, in order to determine whether an individual species can modulate the magnitude of hyoid depression between air and water. High-speed video (250 frames per second) showed that hyoid depression was over three times greater in aquatic than in terrestrial feedings, indicating that T. carolina is able to modulate hyoid depression magnitude depending on the medium in which feeding occurs. In addition, we observed medium-dependent modulation of hyoid depression in another turtle, Heosemys grandis, and large-amplitude hyoid depression during aquatic feeding in Kinosternon leucostomum, Platysternon megacephalum, and juvenile Chelydra serpentina. In all of these turtles, hyoid depression produced oral cavity expansion during aquatic feeding, but the earthworm prey were never sucked toward the predators. Prey were captured by neck extension (ram feeding), and we conclude that the function of hyoid depression during aquatic feeding in cryptodire turtles is to prevent the forward motion of the predator from pushing the prey away (compensatory suction). Aquatic feeding is probably the primitive condition for all extant turtles, and thus terrestrial feeding in T. carolina and other turtles is a secondarily derived characteristic. We conclude from this historical pattern that it is not appropriate to use extant turtles in attempts to reconstruct the terrestrial feeding mechanisms of primitive amniotes.

Animals↗

PubMed2001

Expression of telomerase subunits in normal and neoplastic prostate epithelial cells isolated by laser capture microdissection.

BACKGROUND: Vertebrates have special structures at the ends of their chromosomes, known as telomeres, which may provide the chromosomes with stability and protect them from exonucleolytic degradation. The shortening of telomeric DNA with each cell division may lead to cell cycle arrest and/or apoptosis of a normal human somatic cell. Telomerase, an RNA-dependent DNA polymerase, elongates the 3'-ends of telomeric DNA. Thus, the presence of telomerase activity may reflect a cell's potential immortal state. The telomerase complex is comprised of several subunits. In the current study, the authors describe the use of laser capture microdissection (LCM) to procure pure matched tumor and normal cell populations from histologic sections and to determine the expression of telomerase subunits in these purified samples. METHODS: Pure matched tumor and normal prostate epithelial cells were procured by LCM using fresh frozen tissue samples obtained from patients undergoing radical prostatectomy. RNA was extracted from LCM captured cells, and the subunits for telomerase were assayed by reverse transcriptase-polymerase chain reaction. RESULTS: In 18 samples that were captured with LCM, only the catalytic subunit of telomerase, or hTERT, was found to be discriminatory between tumor cells (17 of 18 specimens, 94.4%) and nontumor cells (none of 18 specimens). TP1, a protein that has been shown to be associated with telomerase activity, was expressed in 3 of 18 normal cells (16.7%) and 15 of 18 tumor cells (83.3%). The RNA subunit of telomerase, or hTR, was expressed in 10 of 18 normal cells (55.6%) and 18 of 18 tumor cells (100%). There was no apparent correlation between telomerase subunit(s) expression and Gleason sum score. CONCLUSIONS: Molecular analyses of LCM cells from prostate carcinoma patient samples demonstrated transcriptional up-regulation of all telomerase subunits in the prostatic epithelium. However, only the catalytic subunit of telomerase, hTERT, was found to be discriminatory between neoplastic versus normal cells (94.4% vs. 0%). This finding suggests that the hTERT subunit may be a useful marker for the detection of prostate carcinoma and/or a potential target for therapy.

Catalytic Domain↗

PubMed2002

Electrophoretic capture of circular DNA in gels.

Results on electrophoretic capture of circular DNA in porous gels are reviewed. Processes which cause arrest of circular forms of DNA during electrophoresis can provide very efficient separation mechanism for the purification of plasmids and bacterial artificial chromosomes if the corresponding linear form is not trapped and therefore removed by the electric field. Two types of such topological traps have been proposed, impalement and lobster traps, and we here review the present experimental support for the existence of these two circle-specific mechanisms. Experiments designed to characterize the traps are discussed, regarding the concentration of the traps as well as their efficiency and capacity to trap both relaxed and supercoiled circular DNA. Studies of the dynamics of the capture process show that the average capture time is on the order of 10 s at 20 V/cm, by which time the circles have migrated several hundred micrometers and have passed hundreds of traps. We also review results on attempts to improve the capacity and efficiency of the trapping process by modification of the gels either by enzymatic treatment or by cogelation of neutral polymers.

DNA, Circular↗

PubMed2005

Trends in work-related musculoskeletal disorder reports by year, type, and industrial sector: a capture-recapture analysis.

BACKGROUND: Musculoskeletal disorders (MSD) are thought to be declining based on Bureau of Labor Statistics survey data, but there is also evidence of MSD under-reporting, raising the possibility of contrary trends. The magnitude of MSD under-reporting over time, and its industry distribution have not been adequately described. METHODS: Capture-recapture analysis of 7 years of Connecticut MSD (1995-2001), utilizing Workers' Compensation and physician reporting data was performed. RESULTS: Only 5.5%-7.9% of MSD cases appear to be reported to Workers Compensation annually. The capture-recapture estimated average annual rate for upper-extremity MSD was 133.1 per 10,000 employed persons, far above BLS rates. By industry, Manufacturing, State Government, and the Finance/Insurance/Real Estate sectors all had significantly higher MSD rates than Wholesale/Retail Trade. CONCLUSIONS: Upper-extremity MSD appears to be significantly under-reported, and rates are not decreasing over time. Capture-recapture methods provide an improved surveillance method for monitoring temporal trends in injury rates.

Adult↗

PubMed2006

Capture and release of DNA using aminosilane-modified bacterial magnetic particles for automated detection system of single nucleotide polymorphisms.

Bacterial magnetic particles (BMPs) were modified with 3-[2-(2-aminoethylamino)-ethylamino]-propyltrimethoxysilane (AEEA) to produce a dense amine surface. Modification of BMPs in a toluene solution resulted in an increased amine yield, and approximately 11.3 x 10(4) surface amines were detected on a single particle. The modified BMPs were capable of efficient electrostatic capture of DNA. The maximum amount of DNA captured on 10 microg of aminosilane-modified BMPs was 600 ng. A 10 mM phosphate buffer effectively released the captured DNA. This efficiency was dramatically enhanced by incubation at 80 degrees C and DNA recovery from aminosilane-modified BMPs approached 95%. DNA extraction from whole blood using these modified BMPs, followed by PCR, was successfully performed. Furthermore, automated single nucleotide polymorphism (SNP) detection of the aldehyde dehydrogenase 2 (ALDH2) was demonstrated.

Bacterial Proteins↗

PubMed2006

Efficient sequence-specific purification of Listeria innocua mRNA species by triplex affinity capture with parallel tail-clamps.

Parallel clamps can interact in a sequence-specific manner with homopyrimidine DNA and RNA oligonucleotides to form triplexes. For longer nucleic acids, we have previously demonstrated the inhibitory effect of DNA-target secondary structures on triplex formation. We further designed a modification of these molecules-that is, tail-clamps formed by addition of a tail sequence to the parallel clamp-and proved efficient binding of the molecules with structured single-stranded DNA targets. Here we explore the possible application of the tail-clamp strategy for triplex formation with RNA targets, which are typically found as strongly folded single-stranded molecules. Efficient and specific binding of a tail-clamp designed to form a parallel triplex with Listeria innocua iap mRNA sequences has been verified by UV melting curves and triplex affinity capture techniques. Furthermore, we show for the first time the formation of stable complexes of mRNA with tail-clamps not only under acidic but also under neutral and slightly basic pH conditions. These results signify a further step towards the possible applications of triplexes with mRNA molecules; research, analytical, and therapeutic uses can be envisaged. As an example, our tail-clamp-based triplex affinity capture assay allowed the specific capture and recovery of iap mRNA molecules from an L. innocua total RNA solution with 45 % yield.

Listeria↗

PubMed1997

Hybridization capture of microsatellites directly from genomic DNA.

A rapid approach for isolation of microsatellites and other tandem repeated sequences in described. The method is based on hybridization capture of repetitive elements from digested genomic DNA using biotinylated oligonucleotide probes in solution and subsequent attachment to magnetic beads coated with streptavidin. Captured fragments are amplified by adapter polymerase chain reaction (PCR) and the PCR products enriched for microsatellites cloned directly into a T-vector for sequencing. The results presented here show that this approach is highly effective, allowing di- and trinucleotide repeats to be isolated and sequenced directly from fish and mammalian genomic DNA within four to five days. Assuming a density and relative abundance of repeats with AC/GT motifs corresponding to that found in the human genome, the protocol presented gives at least a 35-fold enrichment of AC/GT microsatellites using an (AC)10 oligo probe. In addition, four out of five sequences captured by a (CAG)9 oligo probe contained one or several CAG repeat arrays. The efficiency of this direct approach suggests that it can be used for extracting other types of tandem and interspersed repeated sequences (including transposons, rRNA and tRNA genes and proviruses) from vertebrate genomes.

Animals↗

PubMed2003

Analysis of the performance of antibody capture methods using fluorescent peptides with capillary zone electrophoresis with laser-induced fluorescence.

A method to analyze the performance of an antibody capture method using fluorescent peptides by capillary zone electrophoresis using laser-induced fluorescence (CZE-LIF) for detection has been developed. Fluorescent peptides from the prion protein were synthesized and the corresponding antibodies were produced in rabbits against these peptides. The antibodies were used to capture the fluorescent peptides. The antibodies were then bound to protein A Sepharose. After elution, the amount of fluorescent peptide that was captured vs. the total amount placed in the assay was evaluated by CZE-LIF. Of the three peptides used in this evaluation, it was found that the recovery was approximately 25-35%. When the abnormal prion protein was prepared from scrapie-infected brain samples from hamsters and a sheep using the previously described extraction method and this method, the amount of abnormal prion protein that was measured in the fluorescence immunoassay correlated with amounts estimated from Western blot. We conclude that this method can be used to detect abnormal prion protein in a tissue sample.

Amino Acid Sequence↗

PubMed2004

Laser capture microdissection of fluorescently labeled embryonic cranial neural crest cells.

This study is the first to report a unique genetic strategy to permanently label mammalian neural crest cells (NCC) with a fluorescent marker, selectively isolate the labeled NCC or their derivatives during murine ontogenesis by laser capture microdissection (LCM), and prepare molecular components, such as RNA, for selective gene expression analyses. Through utilization of a Cre recombinase/loxP system, a genetic strategy that has been used repeatedly to achieve tissue-specific activation of reporter transgenes in mice, a novel two-component mouse model was created in which neural crest cells (and their progeny) are indelibly marked throughout the pre- and postnatal lifespan of the organism. To generate this mouse model, a Wnt1-Cre transgenic line was crossed with a mouse line expressing a conditional reporter transgene ("floxed" enhanced green fluorescent protein). Resulting offspring, expressing both the Wnt1-Cre and "floxed" EGFP alleles, demonstrated EGFP expression in the NCC and all of their derivatives throughout embryonic, postnatal, and adult stages. In the present study, EGFP-labeled cranial NCC from the first branchial arch of gestational day 9.5 murine embryos were visualized in frozen tissue sections and isolated by LCM under epifluorescence optics. RNA was extracted from "captured" cells and amplified by double-stranded cDNA synthesis and in vitro transcription. Amplified mRNA samples from "captured" cells were evaluated by TaqMan quantitative, real-time PCR for the expression of a panel of NCC gene markers. The molecular genetic strategy delineated in this report will facilitate future embryo-genomic and -proteomic analyses of mammalian NCC that will serve to further our understanding of these pluripotent embryonic progenitor cells.

Base Sequence↗

PubMedDate not supplied

Synthetic peptide vaccine development: measurement of polyclonal antibody affinity and cross-reactivity using a new peptide capture and release system for surface plasmon resonance spectroscopy.

A method has been developed for measurement of antibody affinity and cross-reactivity by surface plasmon resonance spectroscopy using the EK-coil heterodimeric coiled-coil peptide capture system. This system allows for reversible capture of synthetic peptide ligands on a biosensor chip surface, with the advantage that multiple antibody-antigen interactions can be analyzed using a single biosensor chip. This method has proven useful in the development of a synthetic peptide anti-Pseudomonas aeruginosa (PA) vaccine. Synthetic peptide ligands corresponding to the receptor binding domains of pilin from four strains of PA were conjugated to the E-coil strand of the heterodimeric coiled-coil domain and individually captured on the biosensor chip through dimerization with the immobilized K-coil strand. Polyclonal rabbit IgG raised against pilin epitopes was injected over the sensor chip surface for kinetic analysis of the antigen-antibody interaction. The kinetic rate constants, k(on) and k(off), and equilibrium association and dissociation constants, KA and KD, were calculated. Antibody affinities ranged from 1.14 x 10(-9) to 1.60 x 10(-5) M. The results suggest that the carrier protein and adjuvant used during immunization make a dramatic difference in antibody affinity and cross-reactivity. Antibodies raised against the PA strain K pilin epitope conjugated to keyhole limpet haemocyanin using Freund's adjuvant system were more broadly cross-reactive than antibodies raised against the same epitope conjugated to tetanus toxoid using Adjuvax adjuvant. The method described here is useful for detailed characterization of the interaction of polyclonal antibodies with a panel of synthetic peptide ligands with the objective of obtaining high affinity and cross-reactive antibodies in vaccine development.

Amino Acid Sequence↗

PubMed1982

Transmission of hepatitis A virus among recently captured Panamanian owl monkeys.

The presence of antibody to hepatitis A virus (anti-HAV) in 60% of procured owl monkeys (Aotus trivirgatus) held within the United States prompted a study of recently captured A trivirgatus in Panama. Only 2 of 145 newly captured monkeys, but all of 35 A trivirgatus held within a colony for over 100 days, were found to have anti-HAV. Of 41 sero-negative, newly captured monkeys followed prospectively, 25 became infected with hepatitis A virus (HAV) as evidenced by seroconversion or demonstration of virus in the liver at death. Only one monkey that survived over 60 days within the colony was not infected. HAV was identified in the feces of most infected monkeys prior to the development of antibody and was antigenically indistinguishable from human HAV in cross-blocking radioimmunoassays. This colony-centered epizootic provides strong evidence that A trivirgatus is susceptible to HAV and should be investigated further as a potential model of human hepatitis A.

Animals↗

PubMed2004

Induction of HIV-specific antibody response and protection against vaginal SHIV transmission by intranasal immunization with inactivated SHIV-capturing nanospheres in macaques.

We have previously reported that concanavalin A-immobilized polystyrene nanospheres (Con A-NS) could efficiently capture HIV-1 particles and that intranasal immunization with inactivated HIV-1-capturing nanospheres (HIV-NS) induced vaginal anti-HIV-1 IgA antibody response in mice. In this study, to evaluate the protective effect of immunization, each three macaques was intranasally immunized with Con A-NS or inactivated simian/human immunodeficiency virus KU-2-capturing nanospheres (SHIV-NS) and then intravaginally challenged with a pathogenic virus, SHIV KU-2. After a series of six immunizations, vaginal anti-HIV-1 gp120 IgA and IgG antibodies were detected in all SHIV-NS-immunized macaques. After intravaginal challenge, one of the three macaques in each of the Con A-NS- and SHIV-NS-immunized groups was infected. Plasma viral RNA load of infected macaque in SHIV-NS-immunized macaques was substantially less than that in unimmunized control macaque and reached below the detectable level. However, it could not be determined whether intranasal immunization with SHIV-NS is effective in giving complete protection against intravaginal challenge. To explore the effect of the SHIV-NS vaccine, the remaining non-infected macaques were rechallenged intravenously with SHIV KU-2. After intravenous challenge, all macaques became infected. However, SHIV-NS-immunized macaques had lower viral RNA loads and higher CD4(+) T cell counts than unimmunized control macaques. Plasma anti-HIV-1 gp120 IgA and IgG antibodies were induced more rapidly in the SHIV-NS-immunized macaques than in the controls. The rapid antibody responses having neutralizing activity might contribute to the clearance of the challenge virus. Thus, SHIV-NS-immunized macaques exhibited partial protection to vaginal and systemic challenges with SHIV KU-2.

AIDS Vaccines↗

PubMed2005

Characterization of monoclonal antibodies to Marburg virus nucleoprotein (NP) that can be used for NP-capture enzyme-linked immunosorbent assay.

After the first documented outbreak of Marburg hemorrhagic fever identified in Europe in 1967, several sporadic cases and an outbreak of Marburg hemorrhagic fever have been reported in Africa. In order to establish a diagnostic system for Marburg hemorrhagic fever by the detection of Marburg virus nucleoprotein, monoclonal antibodies to the recombinant nucleoprotein were produced. Two clones of monoclonal antibodies, MAb2A7 and MAb2H6, were efficacious in the antigen-capture enzyme-linked immunosorbent assay (ELISA). At least 40 ng/ml of the recombinant nucleoprotein of Marburg virus was detected by the antigen-capture ELISA format. The epitope of the monoclonal antibody (MAb2A7) was located in the carboxy-terminus of nucleoprotein from amino acid position 634 to 647, while that of the MAb2H6 was located on the extreme region of the carboxy-terminus of the Marburg virus nucleoprotein (amino acid position 643-695). These monoclonal antibodies strongly interacted with the conformational epitopes on the carboxy-terminus of the nucleoprotein. Furthermore, these two monoclonal antibodies were reacted with the authentic Marburg virus antigens by indirect immunofluorescence assay. These data suggest that the Marburg virus nucleoprotein-capture ELISA system using the monoclonal antibodies is a promising technique for rapid diagnosis of Marburg hemorrhagic fever.

Amino Acid Sequence↗

PubMed2002

Induction of mucosal IgA following intravaginal administration of inactivated HIV-1-capturing nanospheres in mice.

Concanavalin A-immobilized polystyrene nanospheres (Con A-NS) were developed for the HIV-1 vaccine capable of preventing sexual transmission. Con A-NS could capture efficiently HIV-1 irrespective of their cell tropism (R5 or X4). Furthermore, Con A-NS captured equally infectious and heat-inactivated HIV-1. Inactivated HIV-1-capturing Con A-NS (HIV-NS) were intravaginally administered to mice. Heat-inactivated HIV-1 alone and Con A-NS alone were also administered as control immunogens. Vaginal fluids were collected during and after immunization and analyzed for their anti-HIV-1 antibody levels. Although the anti-HIV-1 IgG antibody was undetectable in any groups, increased anti-HIV-1 IgA antibody response was identified in the vaginal fluids of immunized mice with HIV-NS. The vaginal fluids obtained from the HIV-NS-administered mice showed neutralizing activity against the immunizing HIV-1 strain. A marked difference in vaginal distribution was observed between HIV-NS and other immunogens, and the toxicity of Con A was reduced by conjugation with nanospheres. Thus, HIV-NS may have great potential as a prophylactic HIV-1 vaccine and should be examined further for its efficacy in non-human primates.

Animals↗

PubMed1978

Electron-capture detector GLC technique for estimating tocainide in biological fluids.

A sensitive and specific electron-capture detector GLC method capable of detecting picogram quantities of tocainide, a lidocaine analog, in biological fluids was developed. This method consists of extracting the compound into methylene chloride and derivatizing with heptafluorobutyric anhydride to form the monoheptafluorobutyryl derivative. The derivative formation was confirmed by GLC-mass spectrometry. Quantitative estimation was performed using 1-bromonaphthalene as an internal standard. The minimum detectable level by the electron-capture method was approximately 30 pg/injection as opposed to approximately 3 ng/injection with a flame-ionization detector Linear response was observed in the range from 50 pg to 3 ng using an electron-capture detector. No interference from endogenous substances was observed.

Anilides↗

PubMed2001

Violation of frozen shell approximation in dissociative electron capture by halogenated anthraquinones.

A series of halogenated anthraquinone (AQ) derivatives has been studied by means of electron capture negative ion (NI) mass spectrometry (ECNI-MS). 1Cl-AQ and 2Br-AQ display dramatically steep positive temperature dependencies of Hal(-) ion abundance in the low electron energy region. Molecular NI intensity decreases rapidly with increasing temperature in the case of 1I-AQ. In the case of 2Br-AQ, a metastable NI peak (m/z 22.9) corresponding to the process BrAQ(-) --> Br(-) + AQ(0) was recorded. This means that the characteristic dissociation lifetime of the molecular NI Br-AQ(-) is at least approximately 25 micros at the energy approximately 0.67 eV in the low-temperature spectrum (T approximately 80 degrees C), and at the energy approximately 0.13 eV in the hot spectrum (T approximately 290 degrees C). Together with the observed temperature dependence of the 2Br-AQ curves of effective yield (CEY), this proves that this anion dissociates according to Coulson's model. The same halogen anion behavior is observed in the case of 1Cl-AQ. There are three consecutive stages in the process of molecular NI dissociation of Cl- and Br-substituted AQ, namely, electron capture into the empty pi-orbital by means of the shape resonance mechanism, followed by a radiationless transition into the ground electronic pi-state of the anion, as predicted by Compton in the case of the parabenzoquinone molecule, and, finally, a fluctuative dissociation of the molecular NI accompanied by the transition from the pi-term into the sigma-term, so-called predissociation. Calculations show reasonable agreement with the experimental data. In the case of 1I-AQ, an effect of inversion of empty levels in the process of electron capture by the molecule takes place, a violation of the so-called frozen shell approximation. The phenomenon found may be of significance not only in the case of ECNI-MS, but also in other experimental investigations using low-energy electron-molecule and ion-molecule collisions.

Anthraquinones↗

PubMed2001

Using active medical record review and capture-recapture methods to investigate the prevalence of Down Syndrome among live-born infants in Colorado.

BACKGROUND: In a 1994 comparison of Down Syndrome (DS) birth prevalence rates between 17 states (CDC '94), the average rate for the 17 states was 9.2 per 10,000 live-born infants. Colorado residents had the highest birth prevalence rate (12.3 per 10,000). We investigated the accuracy of this report. METHODS: All children born to Colorado residents during 1989-1991 and reported to CRCSN as having DS went through an active medical record review to eliminate false-positive cases. To adjust for case underascertainment, we used capture-recapture methods to estimate the number of cases missed during surveillance activities. After eliminating false-positive cases and adjusting for case underascertainment, we estimated a new prevalence rate. RESULTS: A total of 198 children born to Colorado residents during 1989-1991 were reported to CRCSN as having DS. Of these, 151 (76%) were definite cases, 25 (13%) were false-positive cases, and 22 (11%) were inconclusive. A log-linear capture-recapture model applied to the definite cases resulted in an estimate of three missing cases. Therefore, the estimated total number of definite DS cases in Colorado was 155 (95% CI = (153-160)) and the new prevalence rate for 1989-1991 was 9.6 per 10,000 live-born infants. CONCLUSIONS: Identifying false-positive cases and applying capture-recapture methods can help identify problems with birth defects surveillance efforts and provide direction for improvements. In Colorado, these techniques identified a problem of false-positive and inconclusive reports of DS. Case underascertainment was discovered not to be a problem.

Colorado↗

PubMed1995

Calibration of biosensor response using simultaneous evanescent wave excitation of cyanine-labeled capture antibodies and antigens.

Fiber optic biosensors have proven their ability to detect antigens rapidly in a variety of environmental and clinical samples. These biosensors are based on the technique of covalently linking antibodies to the core of an optical fiber and detecting antigen binding via measurement of fluorescence induced in the evanescent wave. One problem associated with these biosensors is the fiber-to-fiber variability in measured signal. We have addressed this problem by labeling a portion of the immobilized capture antibody with the fluorescent cyanine dye Cy5.5 (emission lambda max = 696 nm). The antigen was then labeled with fluorescent Cy5 (emission lambda max = 668 nm). Both fluorophores were excited by 635-nm light, and their emission was collected using both a fiber optic spectrometer and a biosensor optimized to collect fluorescence at two wave-lengths. The fluorescence from the Cy5.5-labeled capture antibody served as a calibration signal for each fiber and corrected for differences in optics, fiber defects, and varying amounts of capture antibody present on the fiber. Our data show that normalizing the signal measured from Cy5-labeled antigen binding to the Cy5.5 signal provides a standardization process for greatly reducing signal variance among individual fibers.

Animals↗