Overexpression and enzymatic characterization of Neisseria gonorrhoeae penicillin-binding protein 4.

The penicillin-binding proteins (PBPs) are ubiquitous bacterial enzymes involved in cell wall biosynthesis, and are the targets of the beta-lactam antibiotics. The low molecular mass Neisseria gonorrhoeae PBP 4 (NG PBP 4) is the fourth PBP revealed in the gonococcal genome. NG PBP 4 was cloned, overexpressed, purified, and characterized for beta-lactam binding, DD-carboxypeptidase activity, acyl-donor substrate specificity, transpeptidase activity, inhibition by a number of active site directed reagents, and pH profile.

A poisonous plant of the genus Datura (Solanaceae) in an eighteenth-century Danish garden in West Africa.

There was disagreement among colonialists about whether the Africans around the Danish West African forts made use of native poisons in the early nineteenth century, but it appears that the Danes themselves may have introduced a poisonous ornamental plant of the genus Datura in one of their own gardens on the Guinea Coast.

In vitro degradation of chitosan by bacterial enzymes from rat cecal and colonic contents.

The degradative activities of extracellular and cell-associated portions of rat cecal and colonic enzymes, whose activities are comparable to that in the human colon, against five chitosan samples were characterized. The effects of the molecular weight (MW) and degree of deacetylation (DD) of chitosan on its susceptibility to degradation were investigated. In addition, the degradation function of rat bacterial enzymes was compared to that of a commercially available almond emulsin beta-glucosidase that contains a chitinase.

A study of the psychometric and predictive properties of the Fagerström Test for Nicotine Dependence in a population of young smokers.

This study examined the psychometric properties of the Fagerström Test for Nicotine Dependence (FTND) in a population (N = 7998) of young smokers entering US Air Force Basic Military Training (BMT). An exploratory factor analysis suggested that the FTND is comprised of two factors. The first factor, labeled Smoking Pattern, included items assessing the number of cigarettes smoked per day, time to first cigarette, difficulty refraining from smoking, and smoking when ill.

The folding of nascent mitochondrial aspartate aminotransferase synthesized in a cell-free extract can be assisted by GroEL and GroES.

At 30 degrees C, the precursor to mitochondrial aspartate aminotransferase (pmAspAT) cannot fold after synthesis in rabbit reticulocyte lysate (RRL), a model for studying intracellular protein folding. However, it folds rapidly once imported into mitochondria. Guanidinium chloride denatured pmAspAT likewise cannot refold at 30 degrees C in a defined in vitro system.

Overview of the angiotensin-converting-enzyme inhibitors.

The pharmacology of angiotensin-converting-enzyme (ACE) inhibitors and their role in the renin-angiotensin system (RAS) are described, and pharmacokinetic properties and common adverse events are presented. ACE inhibitors play a vital role in the RAS by regulating the potent vasoconstrictor angiotensin II. All ACE inhibitors share the same basic structure; however, they can be separated on the basis of their functional (binding) group: carboxyl, sulfhydryl, or phosphinyl.

Plans to hasten death among gay men with HIV/AIDS: relationship to psychological adjustment.

This study assessed the prevalence and nature of thoughts and future plans to end one's life in a group of gay men with HIV/AIDS over an 18-month period. HIV-positive men (n = 167) participated in a series of clinical interviews which measured current health status, current and past psychiatric disorders, current levels of distress, and thoughts and plans about ending their lives currently or at some future point. A small number of HIV-positive men (17%) reported serious thoughts or plans to end their lives at some point in the future which were stable over an 18-month period.

Kinetics of a model nucleoside (guanosine) release from biodegradable poly(DL-lactide-co-glycolide) microspheres: a delivery system for long-term intraocular delivery.

The objective of this study was to prepare poly(DL-lactide-co-glycolide) (PLGA) microspheres containing guanosine as a model drug for intraocular administration. Microspheres were prepared by solvent evaporation technique using o/w emulsion system. The influence of composition and molecular weight of PLGA, drug loading efficiency, microsphere size, and in vitro and in vivo release rates were determined.

Ultraviolet-resonance raman spectroscopy of the filamentous virus Pf3: interactions of Trp 38 specific to the assembled virion subunit.

The class II filamentous virus Pf3 packages a circular single-stranded DNA genome of approximately 5833 [corrected] nucleotides within a cylindrical capsid constructed from approximately 2500 [corrected] copies of a 44 residue alpha-helical subunit. The single tryptophan residue (Trp 38) of the capsid subunit is located within a basic C-terminal sequence (.R(+)WIK(+)AQFF).

Raman spectroscopy of protein and nucleic acid assemblies.

The Raman spectrum of a protein or nucleic acid consists of numerous discrete bands representing molecular normal modes of vibration and serves as a sensitive and selective fingerprint of three-dimensional structure, intermolecular interactions, and dynamics. Recent improvements in instrumentation, coupled with innovative approaches in experimental design, dramatically increase the power and scope of the method, particularly for investigations of large supramolecular assemblies. Applications are considered that involve the use of (a) time-resolved Raman spectroscopy to elucidate assembly pathways in icosahedral viruses, (b) polarized Raman microspectroscopy to determine detailed structural parameters in filamentous viruses, (c) ultraviolet-resonance Raman spectroscopy to probe selective DNA and protein residues in nucleoprotein complexes, and (d) difference Raman methods to understand mechanisms of protein/DNA recognition in gene regulatory and chromosomal complexes.

Association of terminal complement proteins in solution and modulation by suramin.

The association of terminal complement proteins was investigated by analytical ultracentrifugation and multi-angle laser light scattering. Native C8 and C9 formed a heterodimer in solution of physiological ionic strength with a free-energy change DeltaG degrees of -8.3 kcal/mol and a dissociation constant Kd of 0.

The pattern of sexual politics: feminism, homosexuality and pedophilia.

Until recently sex and gender issues were thought to be biological or natural rather than political. The feminist movement largely changed perceptions of gender, and the gay and lesbian movements significantly altered conceptions of sex, so that what were once seen as permanent moral standards are now viewed as historical and political constructions. As views of these groups have moved towards social constructionism, perceptions of child sexuality have become more absolutist.

Raman markers of nonaromatic side chains in an alpha-helix assembly: Ala, Asp, Glu, Gly, Ile, Leu, Lys, Ser, and Val residues of phage fd subunits.

The study of filamentous virus structure by Raman spectroscopy requires accurate band assignments. In previous work, site- and residue-specific isotope substitutions were implemented to elucidate definitive assignments for Raman bands arising from vibrational modes of the alpha-helical coat protein main chain and aromatic side chains in the class I filamentous phage, fd [Overman, S. A.

Interaction of Escherichia coli heat-stable enterotoxin B with rat intestinal epithelial cells and membrane lipids.

The binding of 125I-labeled Escherichia coli heat-stable enterotoxin B to rat intestinal epithelial cells was unsaturable and nonspecific, at concentrations well above that required to mediate biological events. Following its interaction with intestinal cells, approximately 50-80% of heat-stable enterotoxin B remained stably associated with the cells, implying that it was partitioned into the membrane and/or internalized by the cell. The toxin bound with different affinities to lipids isolated from intestinal epithelial cells, phospholipids, glycolipids, neutral lipids and to model membrane vesicles containing negatively charged lipids.

Demonstration by ultraviolet resonance Raman spectroscopy of differences in DNA organization and interactions in filamentous viruses Pf1 and fd.

Pf1, a class II filamentous virus, has been investigated by ultraviolet resonance Raman (UVRR) spectroscopy with excitation wavelengths of 257, 244, 238, and 229 nm. The 257-nm UVRR spectrum is rich in Raman bands of the packaged single-stranded DNA (ssDNA) genome, despite the low DNA mass (6%) of the virion. Conversely, the 229-nm UVRR spectrum is dominated by tyrosines (Tyr 25 and Tyr 40) of the 46-residue alpha-helical coat subunit.

Syntheses and beta-adrenergic binding affinities of (R)- and (S)-fluoronaphthyloxypropanolamines.

The beta-adrenergic receptors mediate several physiological processes including heart rate (beta 1), bronchodilation (beta 2), and lipolysis (beta 3). Therefore, selectivity is important for a possible therapeutic agent acting via these receptors. Aryloxypropanolamines are beta-receptor agonists or antagonists, depending on the aryl group and its substituents.

An examination of body weight standards and the association between weight and health behaviors in the United States Air Force.

This study examined the weight standards used by the U.S. Air Force and tested whether Air Force personnel who exceed the maximum allowable weight standard are more likely to engage in health risk behaviors compared with individuals who do not exceed current Air Force weight standards.

Molecular mechanism of DNA recognition by the alpha subunit of the Oxytricha telomere binding protein.

Interactions between telomeric DNA and the alpha subunit of the heterodimeric telomere binding protein of Oxytricha nova have been probed by Raman spectroscopy, CD spectroscopy, and nondenaturing gel electrophoresis. Telomeric sequences investigated include the Oxytricha 3' overhang, d(T4G4)2, and the related sequence dT6(T4G4)2, which incorporates a 5'-thymidylate leader. Corresponding nontelomeric isomers, d(TG)8 and dT6(TG)8, have also been investigated.

Negative aging stereotypes and the agentic-communal dichotomy.

Prior research has documented negative aging stereotypes. Our hypothesis is that these only apply when a certain dimension of traits is employed and when older persons occupy certain roles. 42 college students were asked to rate the extent to which each of several "agentic" traits, e.

Smoking prevalence and risk factors for smoking in a population of United States Air Force basic trainees.

Objective: To provide a comprehensive assessment of smoking prevalence and risks for smoking in an entire population of United States Air Force (USAF) military basic trainees (n = 32,144).

Design: Population-based survey with every individual entering the USAF enlisted force from August 1995 to August 1996.

Setting: USAF Basic Military Training (BMT) facility at Lackland Air Force Base, Texas.

Conformation and interactions of the packaged double-stranded DNA genome of bacteriophage T7.

The structure of the packaged double-stranded DNA genome of bacteriophage T7 was compared to that of unpackaged T7 DNA using digital difference Raman spectroscopy. Spectral data were obtained at 25 degrees C from native T7 virus (100 mg/mL), empty T7 capsids (50 mg/mL), and purified T7 DNA (40 mg/mL) in buffer containing 200 mM NaCl, 10 mM MgCl2, and 10 mM Tris at pH 7.5.