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A mufF conditional mutant was used to evaluate the effect of suboptimal transcription of this on the transcriptome of the methicillin-resistant Staphylococcus aureus strain COL. The mutant was grown in the presence of optimal and suboptimal concentrations of the inducer, and the relative levels of transcription of genes were evaluated genome wide with an Affymetrix DNA microarray that included all open reading frames (ORFs) as well as intergenic sequences derived from four sequenced S. aureus strains. Using a sensitivity threshold value of 1.5, suboptimal expression of murF altered the transcription of a surprisingly large number of genes, i.e., 668 out of the 2,740 ORFs (close to one-fourth of all ORFs), of the genome ofS. aureus strain COL. The genes with altered transcription were distributed evenly around the S. aureus chromosome, and groups of genes involved with distinct metabolic functions responded in unique and operon-specific manners to modulation in murF transcription. For instance, all genes belonging to the isd operon and all but 2 of the 35 genes of prophage L54a were down-regulated, whereas all but one of the 21 members of the vraSR regulon and most of the 79 virulence-related genes (those for fibronectin binding proteins A and B, clumping factor A, gamma hemolysin, enterotoxin B, etc.) were up-regulated in cells with suboptimal expression of murF. Most importantly, the majority of these altered gene expression profiles were reversible by resupplying the optimal concentration of IPTG (isopropyl-[beta]-D-thiogalactopyranoside) to the culture. The observations suggest the coordinate regulation of a large sector of the S. aureus transcriptome in response to a disturbance in cell wall synthesis.

Reversible transitions between the A- and B- forms of DNA are obtained in free molecular dynamics simulations of a single double helix immersed in a water drop with Na(super +) counterios. Analysis of the available experiment data suggests that the mechanism is generally responsible for the A/B polymorphism in DNA.

The isotope effects for anionic-exchange HPLC retention time that represent slight differences in the pKa of glucopyranose hydroxyl groups are reported. Most of the charge in ionized glucose at pH 11.7 is carried by OH1 with some participation by OH4.

A study describing a novel folding pattern of a DNA oligonucleotide d(G3T4G4), which adopts an asymmetric bimolecular G-quadruplex structure in solution is presented. The solution structure of d(G3T4G4)2 that is consistent with all NMR data is composed of three G-quarters, overhanging G11 residue and G3, which is part of a loop.

A nanoparticle-based drug carrier for photodynamic therapy is reported which can provide stable aqueous dispersion of hydrophobic photosensitizers, at the same time preserve the main step of photogeneration of singlet oxygen, necessary for photodynamic action. The potential of using ceramic-based nanoparticles as drug carriers for photodynamic therapy is demonstrated.

Direct measurement of the specific activity of labeled penicillin bound to the penicillin-binding proteins in Staphylococcus aureus reveals approximately 150 to 825 penicillin-binding proteins per cell.

Research has been conducted on the beta-galactose-conjugated purpurinimides, a class of chlorins prepared from purpurin-N-propargylimide via enyne metathesis. The synthesis and biological evaluation of these compounds recognized as galectin-1 photosensitizers are reported.

Research has been conducted on the reaction of porphyrins with osmium tetraoxide. The effect of the electron-donating and electron-withdrawing substituents on these porphyrins has been investigated.

Research describes the syntheses of a variety of fluorinated and nonfluorinated benzochlorins exhibiting varying lipophilicity from nickel(II)octaethylporphyrin. Results indicate that the lipophilicity variation, caused by increasing the length of the alkyl or alkyl ether carbon units of the phenyl ring system, alters benzochlorins' pharmacokinetic profiles and increses in tumor uptake.

Research has been conducted on the spirochlorin-chlorin dimer with fixed distances. The reaction of Witting reagent with photoprotoporphyrin IX dimethyl ester is discussed.

The effects of substituents in the benzobacteriochlorin series was investigated by preparing and evaluating the biological activity of the hexyl ether derivative. A chlorophyll biosynthetic intermediate was successfully synthesized, which was then extended to the preparation of another biosynthetic intermediate, methyl 3,8-divinylpheophorbide alpha. The results showed that the synthetic procedure developed provided the preparation of the target compound in the fewest steps possible, avoiding wasteful yield losses and minimizing synthesis time.

Methylpheophorbide-a (a chlorophyll a analog) was converted into methyl [13.sup.1]-deoxypyropheophorbide-a 2 in excellent yield. The Ni(II) complex of 2 on hydrogenation and subsequent Viismeier reaction with phosphorus oxychloride and 3-(N,N-dimethylamino)acrolein produced Ni(II) methyl 20-(2-formylvinyl)-[13.sup.1]-deoxypyropheophorbide-a 4. In contrast to other synthetic and naturally occurring isobacteriochlorins, the isobacteriochlorin obtained by acid-catalyzed cyclization of 4 was found to be unstable and oxidized to the corresponding benzochlorin. The free base benzochlorin 7, obtained by demetalation, up on DDQ/methanol treatment produced a mixture of [13.sup.2]-oxo- and [13.sup.1]-methoxy-[13.sup.2]-oxobenzochlorins 8, 9. Surprisingly, under similar reaction conditions, an ethanolic solution of DDQ afforded [13.sup.1], [13.sup.2]-dioxobenzochlorin 13 as a major product. Vilsmeier reaction ([POC1.sub.3]/DMF) of Ni(II) benzochlorin 6 gave unexpected 5-formyl-[13.sup.2]-oxobenzochlorin 15. Zn(II) complexes of the newly synthesized benzochlorins showed long wavelength absorptions in the range of 750-753 nm. Thus, compared to the respective free base analogues bathochromic shifts of 4042 nm were observed. Despite extensive studies in benzochlorins, these are the first examples which exhibit such remarkable long wavelength absorptions in their electronic absorption spectra. The structures of novel benzochlorins were confirmed by extensive NMR [2D NMR (ROESY), 13C NMR] and X-ray crystallographic studies. On the basis of the crystal structure of oxobenzochlorin 8, the chemical reactivity of other benzochlorin analogues were examined by semiempirical molecular orbital theory. Our results are in agreement with the previous qualitative electron sextet hypothesis proposed for chlorin systems by Woodward. The fluorescence quantum yields and the singlet oxygen yields of the free base and Zn(II) benzochlorins were measured relative to tetraphenylporphyrin (TPP) in benzene.

The cell wall-cell division gene clusters in pathogenic gram-positive cocci were examined to determine it identification and characterization. The experiment identified and sequenced in two gram-positive cocci, the clusters of peptidoglycan biosynthesis and cell division genes. Results showed significant differences in the comparative sizes of div1B and ftsQ genes, and the absence of several genes.

The regioselective oxidation of pyrrole units in porphyrin and chlorin systems by OsO4 were analyzed to determine the kinetic properties of the synthetic process. Analysis of the OsO4-mediated regioselective oxidation of porphyrin and chlorin systems indicated the role of electron-withdrawing groups at various points of the macrocycles in modulating the synthetic reaction. Furthermore, the position and number of electron-withdrawing groups at various points of the substituents also affected their migratory behavior during pinacol-pinacolone rearrangements.

The number of molecules per cell of the individual penicillin-binding proteins (PBPs) was determined directly in Escherichia coli by measuring both the cell numbers present and the radioactivity in the individual PBPs from a precise quantity of cells. Care was taken to make sure that the individual PBPs were saturated with (3H)penicillin and an adequately large sample was taken in separate experiments to permit statistical assessment of the data sets. Findings showed that the original values computed by B.G. Spratt in 1977 are fairly accurate except for higher values derived for PBP 2 and 3.

Examination of the interaction of UDP-N-acetylmuramyl-L-alanine with Escherichia coli glutamate racemase indicates that UDP-N-acetylmuramyl-L-alanine functions as an enzyme activator. Optimal activation of the enzymes requires the presence of longer N-terminal region of the enzyme. Site-directed mutagenesis and solvent isotope exchange studies indicate that the activated E. coli glutamate racemase follows a deprotonation/reprotonation mechanism.

Genetic complementation studies reveal the presence of D-amino acid transaminase (dat) and glutamate racemase (dga) biosynthetic enzymes in Staphylococcus haemolyticus. One of the two gene products isolated from S. haemolyticus shows significant similarity with Dga proteins from Pediococcus pentosaceous and the other with Dat proteins from Bacillus spp. DNA hybridization studies indicate the presence of homologous chromosomal DNA for both dga and dat genes in Staphylococcus aureus.

Two Escherichia coli genes required in the production of D-glutamate were identified by mutation analysis. The first gene, designated dga, located at 89.9 min on the E. coli genetic map, was identified as a previously identified open reading frame. The second gene, localized at 82 min, is involved in the transport of D- and L-glutamic acid into E. coli. Both mutations were required in the construction of D-glutamic acid auxotrophs.

The murB gene of Escherichia coli coding for UDP-N-acetylenolpyruvoylglucosamine reductase was isolated, cloned, subcloned and sequenced to characterize the locus. Nucleotide sequence analysis of the gene revealed a reading frame consisting of 1,029 base pairs which encodes a 37,859 dalton polypeptide with 342 amino acid residues. Further, the nucleotide sequence is 100% homologous with a known reading frame called ORFII. Mapping of the gene and analysis of its product were also conducted to further characterize the locus.