BIO-INSPIRED MAGNETIC BEADS FOR ISOLATION OF SPERM FROM HETEROGENOUS SAMPLES IN FORENSIC APPLICATIONS.

Rapid and efficient processing of sexual assault evidence will accelerate forensic investigation and decrease casework backlogs. The standardized protocols currently used in forensic laboratories require the continued innovation to handle the increasing number and complexity of samples being submitted to forensic labs. Here, we present a new technique leveraging the integration of a bio-inspired oligosaccharide (i.

A confirmatory test for sperm in sexual assault samples using a microfluidic-integrated cell phone imaging system.

Rapid and efficient processing of sexual assault evidence to accelerate forensic investigation and decrease casework backlogs is urgently needed. Therefore, the standardized protocols currently used in forensic laboratories can benefit from continued innovation to handle the increasing number and complexity of samples being submitted to forensic labs. To our knowledge, there is currently no available rapid and portable forensic screening technology based on a confirmatory test for sperm identification in a sexual assault kit.

A Novel On-Chip Method for Differential Extraction of Sperm in Forensic Cases.

One out of every six American women has been the victim of a sexual assault in their lifetime. However, the DNA casework backlog continues to increase outpacing the nation's capacity since DNA evidence processing in sexual assault casework remains a bottleneck due to laborious and time-consuming differential extraction of victim's and perpetrator's cells. Additionally, a significant amount (60-90%) of male DNA evidence may be lost with existing procedures.

The DAVID (Dual Chamber and VVI Implantable Defibrillator) II trial.

Objectives: The purpose of this study was to determine whether atrial pacing is a safe alternative to minimal (backup-only) ventricular pacing in defibrillator recipients with impaired ventricular function.

Background: The DAVID (Dual Chamber and VVI Implantable Defibrillator) trial demonstrated that dual chamber rate responsive pacing as compared with ventricular backup-only pacing worsens the combined end point of mortality and heart failure hospitalization. Although altered ventricular activation from right ventricular pacing was presumed to be the likely cause for these maladaptive effects, this supposition is unproven.

Using a CCD camera imaging system as a recording device to quantify human DNA by slot blot hybridization.

Slot blot hybridization of membrane-immobilized, single-stranded human DNA with the higher primate-specific alphoid probe D17Z1 is routinely used in forensic science to estimate the amount of DNA in biological samples. Typically, a chemiluminescent signal captured on film records the hybridization, and the quantity of the signal is related to the amount of immobilized DNA. Digital imaging using a cooled CCD camera offers an alternate non-film-based method for image acquisition with comparable sensitivity of detection, a greater dynamic range, enhanced capability of data interpretation, and often faster results than film.

Inhibition of antagonist and agonist binding to the human brain muscarinic receptor by arachidonic acid.

Arachidonic acid (AA) inhibits the binding of [3H]quinclidinyl benzilate ([3H]QNB) to the human brain muscarinic cholinergic receptor (mAChR). AA inhibits at lower concentrations in the absence of glutathione (I50 = 15 microM) than in the presence of glutathione (I50 = 42 microM). Inhibition of mAChR binding shows specificity for AA and is reduced with loss of one or more double bonds or with either a decrease or increase in the length of the fatty acid chain.

Simple protocols for typing forensic biological evidence: chemiluminescent detection for human DNA quantitation and restriction fragment length polymorphism (RFLP) analyses and manual typing of polymerase chain reaction (PCR) amplified polymorphisms.

Methods for identity testing are described that enable extraction of DNA from biological samples, determination of the quantity of human DNA, and genetic analyses of the materials using restriction fragment length polymorphism (RFLP) typing and/or amplified fragment length polymorphism (AMP-FLP) typing of PCR products. The salient features of the procedures are simplicity, manual typing, nonradioactive chemiluminescent assays or silver staining for detection, and low cost. Most application-oriented laboratories involved in forensic and/or paternity testing should be able to implement these procedures.

Chemiluminescent detection of DNA probes in forensic analysis.

The conditions for hybridization and detection of enzyme-labeled probes have been optimized in our laboratory for use with oligonucleotides coupled to alkaline phosphatase. We have examined several enzyme-linked probe which are complimentary to commonly used variable number of tandem repeats (VNTR) loci to determine the feasibility of using chemiluminescence for routine application in forensic DNA analysis. It was found that a chemiluminescent detection system employing an alkaline phosphatase activated dioxetane in the presence of chemiluminescent enhancers provides a high degree of sensitivity in hybridization protocols with a significant savings in overall filter processing time.

Rapid isolation of DNA from complex biological samples using a novel capture reagent--methidium-spermine-sepharose.

We have synthesized and analyzed the functional properties of a novel DNA capture reagent containing a methidium moiety attached to a sepharose bead by a spermine linker. DNA present in a biological fluid or other complex sample binds to the reagent. The DNA-capture reagent complex is then separated from the sample by centrifugation and the DNA is released from the reagent by brief incubation in 0.

Novel biotinylated nucleotide--analogs for labeling and colorimetric detection of DNA.

A series of dATP and dCTP nucleotide analogs have been synthesized which are modified by attachment of aliphatic linkers containing a functional group to the amino-nitrogen at the hydrogen bonding positions of the bases, that is, at the 6-position of adenine and the 4-position of cytosine. These nucleotides are incorporated into DNA probes by standard nick-translation protocols. DNA probes labeled with biotin derivatives of these nucleotides are effectively hybridized to target DNA sequences and can be detected by a streptavidin and calf intestinal alkaline phosphatase conjugate with a sensitivity (0.

Gyrase . DNA complexes visualized as looped structures by electron microscopy.

Gyrase bound to duplex DNA in the absence of ATP is seen by electron microscopy as a nearly spherical particle frequently located at the intersection of two duplex DNA strands. Such looped structures with gyrase situated at the base of the loops are observed with both linear and circular DNA substrates, and two or three individual DNA molecules bound to the same protein are also seen at high DNA concentrations. Addition of the nonhydrolyzable beta,gamma-imido analog of ATP to the gyrase .

Stabilization of Z-DNA by polyarginine near physiological ionic strength.

The identification of left handed or Z-DNA in solutions of poly d(GC) in high salt suggests that left handed DNA may exist in biological systems if stabilized at lower ionic strength. In the present study we show that binding of polyarginine to the Z form of poly d(GC) results in a protein-Z-DNA complex stable near physiological ionic strength. The percentage of Z-DNA in the low salt polyarginine-poly d(GC) complex was measured from the DNA circular dichroism spectrum.

Deoxyribonucleic acid gyrase-deoxyribonucleic acid complex containing 140 base pairs of deoxyribonucleic acid and an alpha 2 beta 2 protein core.

Staphylococcal nuclease digestion of the complex between DNA and DNA gyrase yields a gyrase-DNA core particle composed of a 140 base pair DNA segment and an active gyrase enzyme. The partial specific volume and S20,w of this purified core complex are measured to be 0.70 cm3/g and 14.

31P NMR studies of the solution structure and dynamics of nucleosomes and DNA.

31P NMR studies of 140 base pair DNA fragments in nucleosomes and free in solution show no detectable change in the internucleotide 31P chemical shift or linewidth when DNA is packaged into nucleosomes. Measurements of 31P spin-lattice relaxation times T1 and 31P-[H] nuclear Overhauser enhancements revealed internal motion with a correlation time of about 4 x 10(-10) sec in double helical DNA, both free in solution and bound to nucleosomal core proteins. This result implies greater dynamic mobility in double helical DNA than has previously been supposed.

Physical studies of nucleosome assemble.

Biochemical, spectroscopic, and hydrodynamic studies were performed on the reconstituted complex of 140 base pair DNA and the arginine-rich histone tetramer (H3/H4)2. The histones bind to DNA in a 1:1 molar ration to form a stable particle which orients in an electric field with a rotational correlation time of 6.3 mus and a limitign reduced dichroism of --0.

Transient electric dichroism studies of nucleosomal particles.

We report transient electric dichroism experiments on nucleosomal core particles containing 140 and 175 base pairs of DNA, and on spacerless dinucleosomes. The results indicate that all particles posses a permanent dipole moment. The orientation time of 140 base pair nucleosomes implies an estimated maximum dimension of a = 130 A (a must be at least 111 A), consistent with the disk model.

Isolation and characterization of a spacerless dinucleosome from H1-deleted chromatin.

Calf thymus chromatin, depleted in histone H1, was digested with micrococcal nuclease and fractionated by column chromatography. 140 base pair nucleosome core particles were isolated along with an unusual particle containing 2 histone octamers and 240 base pairs of DNA. Evidence is presented that the spacer DNA region is absent from these modified dinucleosomes, which appear as stable products of the digestion process.