Novel tyrosine markers in Raman spectra of wild-type and mutant (Y21M and Y24M) Ff virions indicate unusual environments for coat protein phenoxyls.

The tyrosine side chain generates a pair of distinctive Raman bands--a Fermi doublet near 850 and 830 cm-1--with relative intensities diagnostic of hydrogen bonding states of the phenolic acceptor and donor atoms [Siamwiza et al. (1975) Biochemistry 14, 4870-4876]. This structural correlation has been tested extensively and is used widely as an indicator of tyrosine interactions in globular proteins and their assemblies.

Update on AIDS and sexual behavior of college students: seven years later.

This survey of 54 single, sexually active college students indicated that there has been a significant increase in concern about AIDS compared to a survey on a similar sample in 1985. A majority of this sample have been involved in monogamous relationships during the past year and 35% have had the AIDS test on which no seropositive results were reported. Yet, despite an increase in AIDS in the nation's heterosexual population, the majority of students continue to engage in unprotected sexual relations.

Vibrational analysis of nucleic acids. I. The phosphodiester group in dimethyl phosphate model compounds: (CH3O)2PO2-, (CD3O)2PO2-, and (13CH3O)2PO2-.

Normal coordinate analyses and vibrational assignments are presented for the dimethyl phosphate anion [(CH3O)2PO2-] and its deuteriomethyl [(CD3O)2PO2-] and carbon-13 [(13CH3O)2PO2-] derivatives in the gauche-gauche conformation. The dimethyl phosphate anion, which is the simplest model for the nucleic acid phosphodiester moiety, exhibits many of the spectral complexities of DNA and RNA and has previously resisted a complete and consistent vibrational analysis. In the present study we make use of new experimental data on the dimethyl phosphate isotopomers, including Raman depolarization measurements, to develop a consistent valence force field for normal modes of the C--O--P--O--C phosphodiester network and its hydrogenic substituents, as well as for stretching and bending modes of the O--P--O network of the anionic phosphodioxy group (PO2-).

Raman dynamic probe of hydrogen exchange in bean pod mottle virus: base-specific retardation of exchange in packaged ssRNA.

We describe a novel approach to investigating exchange kinetics in biological assemblies. The method makes use of a Raman multichannel analyzer coupled with a dialysis flow cell. We employ this methodology to determine exchange rates of labile hydrogens in both the packaged RNA genome and protein subunits of bean pod mottle virus (BPMV).

Diffusion and concentration profiles of drugs in gels.

A versatile membraneless method was used to study the diffusion of acetaminophen, ibuprofen, indomethacin, theophylline, and chlorpheniramine in thermoreversible gels. Two independent ways to calculate the diffusion coefficients and to verify Fickian transport are presented; the most sensitive criterion for Fickian transport being an agreement between the concentration profile for the drug in the gel and the free diffusion model. The diffusion of acetaminophen, ibuprofen, and indomethacin was studied at different temperatures in 1% (w/w) agarose gels.

Spatial displacement among pedestrians: a cross-cultural replication.

An observational study of pedestrians in a shopping mall in a mid-western U.S. city was replicated in shopping malls in London.

Cysteine conformation and sulfhydryl interactions in proteins and viruses. 3. Quantitative measurement of the Raman S-H band intensity and frequency.

The bond stretching vibration of the cysteine sulfhydryl (SH) group in a typical protein generates a Raman band in the spectral interval 2500-2600 cm-1, a region devoid of interference from any other fundamental mode of vibration of the protein. The relatively high Raman cross section associated with the S-H stretching vibration, the sensitivity of the vibrational frequency to hydrogen bonding interactions and side chain configurations, and the dependence of the Raman intensity on thiol-thiolate equilibria, combine to make the Raman SH band a potentially valuable marker of protein sulfhydryl interactions and a unique indicator of sulfhydryl participation in thiol-disulfide oxidoreductase activity. In order to exploit Raman spectroscopy for these purposes, accurate and precise measurements of Raman SH band profiles are required.

Relative ground and excited state energies of CH3(CH = CH)5CH = NC4H9, its hydrogen-bonded and proton-transferred species, and charge partitioning and distribution in the protonated Schiff base of retinal.

CH3(CH = CH)5CH = NC4H9 (compound 1) is structurally related to the Schiff base of retinal, the prosthetic group in visual pigments. Dilute solutions of a weak acid (phenol) and 1 in a hydrocarbon solvent, when subjected to decreasing temperature, show striking changes in electronic absorption spectra. Initially only the spectrum of compound 1 is present, but as the temperature is lowered, the absorbance of 1 decreases, and the spectrum of the H-bonded form of 1 appears and increases.

Characterization of hemopexin and its interaction with heme by differential scanning calorimetry and circular dichroism.

Hemopexin is a plasma glycoprotein that has two structural domains (I and II) and binds and transports heme particularly to liver cells. Differential scanning calorimetry (DSC) studies show that hemopexin is largely stabilized by heme, which binds exclusively to domain I. The melting temperature (Tm) of heme-hemopexin is 66.

Efficient large-scale purification of restriction fragments by solute-displacement ion-exchange HPLC.

Extreme overloading of HPLC columns with sample can create a condition of binding site saturation causing competition and displacement among solutes during column elution. This has been termed solute-displacement chromatography (SD-HPLC). We present an example of this phenomenon for the preparative fractionation and purification of restriction fragments of almost identical size (1337 and 1388 bp) which cannot be resolved by agarose gel electrophoresis.

Victim resistance and judgments of victim "consensuality" in rape.

38 participants read about a man who entered a woman's apartment at night, told her that "all he wanted was sex," engaged in the act of sex regardless of what she said or did, and then left. Participants then made a preliminary rating of their agreement or disagreement with the statement. "The woman consented to have sex.

Regulation of heme oxygenase and metallothionein gene expression by the heme analogs, cobalt-, and tin-protoporphyrin.

Two heme analogs, cobalt- and tin-protoporphyrin (CoPP and SnPP, respectively) have been used to probe the heme-hemopexin interaction, hemopexin receptor binding, and the mechanism of regulation of heme oxygenase (HO) and metallothionein-1 (MT-1) gene expression by hemopexin. Both CoPP and SnPP are HO inhibitors and hemopexin binds SnPP (Morgan, W. T.

Evaluation of a brief measure of depressive mood for use in a university counseling center.

To study the reliability of Set 1 (A, B, C, D) and Set 2 (E, F, G) of the state and trait forms of the Depression Adjective Check Lists in university counseling centers, four independent studies were conducted. Reliability (internal consistency, split-half, and alternate form) and validity (convergent and discriminant) for both sets and both forms were sufficiently high to warrant use for research and clinical purposes. Additional research needs were mentioned.

Oestrone loaded poly(l-lactic acid) microspheres: preparation, evaluation and in vitro release kinetics.

Poly(l-lactic acid) microspheres containing oestrone were prepared by the solvent evaporation method using methylene chloride as the casting solvent and poly(vinyl alcohol) as the emulsifier. Non-agglomerated microspheres with average diameters of 125-160 microns, containing 3-18 per cent oestrone were prepared successfully using a stirring rate of 650 rpm and a poly(vinyl alcohol) concentration as low as 0.15%.

Demonstration of Z-d(5BrCGAT5BrCG) and B-d(CGCGATCGCG) form crystal structures in DNA-cobalt hexammine complexes by Kr 647.1 nm excitation of Raman spectra.

Cobalt hexammine [Co(NH3)6(3+)] is an efficient DNA complexing agent which significantly perturbs nucleic acid secondary structure. We have employed red excitation (647.1 nm) from a krypton laser to obtain Raman spectra of the highly colored complexes formed between cobalt hexammine and crystals of the DNA oligomers, d(5BrCGAT5BrCG) and d(CGCGATCGCG), both of which incorporate out-of-alternation pyrimidine/purine sequences.

Identification of the histidine residues of hemopexin that coordinate with heme-iron and of a receptor-binding region.

Rabbit hemopexin cDNA was cloned from a rabbit liver lambda gt11 cDNA expression library using a mixture of five monoclonal antibodies raised against rabbit hemopexin, and the entire rabbit hemopexin sequence was determined. The heme-binding domain I of rabbit hemopexin (Smith, A., and Morgan, W.

Structural studies of the enveloped dsRNA bacteriophage phi 6 of Pseudomonas syringae by Raman spectroscopy. I. The virion and its membrane envelope.

We report and interpret the first Raman spectrum of a double-stranded RNA virus containing a membrane envelope. Spectra of the native bacteriophage phi 6 and of its isolated host-attachment (spike) protein and phospholipid-free core assembly were collected from aqueous solutions over a wide range of temperature. Comparison of the vibrational spectra by digital difference methods permits the following structural conclusions regarding molecular constituents of the fully assembled virion.

Effects of lysophospholipids and diacylglycerols on the transfer of arachidonic acid to phospholipids and triacylglycerols in rat brain membranes.

Brain membranes catalyze the acylation of lysophospholipids and diacylglycerols (DAG) to form the respective phospholipids and triacylglycerols (TAG). These acylation reactions were examined using brain plasma membrane-enriched fractions by measuring the incorporation of [14C]arachidonic acid into TAG and individual phospholipids under a variety of conditions. In the absence of added lipid substrates, the amount of [14C]arachidonic acid incorporated into TAG in the presence of ATP, Mg2+, and CoA was approx twice the amount incorporated into phosphatidylositol (PtdIns), and more than 10 times the amount incorporated into phosphatidylcholine (PtdCho), phosphatidylethanolamine (PtdEtn) and phosphatidylserine (PtdSer).

Antihypertensive therapy in the geriatric patient: II. A review of the alpha1-adrenergic blocking agents.

The prevalence of hypertension increases with age. Multiple physiologic factors are involved in the development of hypertension in the elderly. Alpha1-adrenergic blocking agents lower blood pressure through a reduction in total peripheral resistance.

Secondary structure and interactions of the packaged dsDNA genome of bacteriophage P22 investigated by Raman difference spectroscopy.

Vibrational spectra of the double-stranded DNA genome of bacteriophage P22 in packaged and unpackaged states are compared by digital difference Raman spectroscopy. The difference Raman spectrum, which is sensitive to structural changes at the level of < 2% of a given nucleotide type, reveals the effects of packaging upon sugar pucker, glycosyl orientation, phosphodiester geometry, base pairing, base stacking, and the electrostatic environment of DNA phosphate groups. For both packaged and unpackaged states, the experiments were performed on aqueous solutions at 25 degrees C containing effective P22 DNA concentrations of 30-50 mg/mL in 200 mM NaCl + 10 mM MgCl2 + 10 mM Tris at pH 7.

Mapping of monoclonal antibody epitopes in the nucleolar protein fibrillarin (B-36) of Physarum polycephalum.

We have mapped the epitopes for nine monoclonal antibodies raised against the nucleolar protein fibrillarin of the slime mold Physarum polycephalum. This has been done using a combination of specific chemical and enzymatic cleavage, Western blotting and partial sequencing of fragments. Cleavage with cyanogen bromide reveals four prominent methionine cleavage sites within the protein.

Electrophysiology of nitrous oxide on cerebellar granule cells: a single-cell study.

We recorded 18 single cells in the granule cell layer of the cat. Each single cell was screened and identified as a granule cell based on a set of criteria derived from known electrophysiological properties of granule cells. We then monitored the effects of nitrous oxide on the spontaneous activities and the auditory responses of these cells.

Purification of the STB enterotoxin of Escherichia coli and the role of selected amino acids on its secretion, stability and toxicity.

The methanol-insoluble heat-stable enterotoxin of Escherichia coli (STB) was purified and characterized by automated Edman degradation and tryptic peptide analysis. The amino-terminal residue, Ser-24, confirmed that the first 23 amino acids inferred from the gene sequence were removed during translocation through the E. coli inner membrane.