Proton transfer reactions in aqueous solutions of pyridoxamine phosphate

UV-visible and ¹³C NMR measurements described in the literature and our ³¹P NMR measurements support the following mechanism of proton transfer reactions in aqueous solutions of pyridoxamine phosphate: Only the tautomeric equilibrium between neutral form, A _N, and zwitterion, A _Z, which is analogous to the tautomeric equilibrium of 3-hydroxypyridine in aqueous solution, is important, and that equilibrium does not change upon the dissociation of the second phosphate proton. With these simplifying assumption, we have simulated the relaxation spectrum of the proton transfer reactions of pyridoxamine phosphate in water using parameters from analogous reactions and compared it with our ultrasound and temperature jump measurements. We have found that the relaxation process measured by the temperature jump experiment is mainly caused by the overall reaction A _N=A _Z (or A _N ^- =A _Z ^- ) and the ultrasound absorption at the isoelectric point between pK₂ and pK₃ is mainly caused by the overall reaction .     

Enzymatic production of L-tryptophan in a reverse micelle reactor

The enzymatic production of tryptophan from indole and serine was investigated in a micellar solution of the surfactant Brij 56 in cyclohexane. An anion exchanger was employed to facilitate the transfer of tryptophan and serine between the water pool of the reverse micelle and the bulk organic phase. The influence of potassium ion, water content, pH, and co-surfactant on enzyme activity is reported. Kinetic studies indicate that the enzyme is not inhibited by indole in the micellar system and that the enzyme is more stable in reverse micelles than in bulk water. The design of a continuous reverse micelle reactor, which accommodates both product recovery and enzyme reactivation, is discussed.     

Experimental reovirus myocarditis in newborn mice. Electron microscopic observations

Reovirus is a double-stranded RNA-virus which induces myocarditis in newborn mice. Due to the large diameter of the viral particles (70-75 nm) it can be detected by electron microscopy. Subcutaneous inoculation of 0.05 ml reovirus type 3 (TCID50-titer: 10(8.5)/ml) into newborn NMRI-mice (12-18 h after birth) caused a grey-yellow mottling on the ventricular surface first seen on the 5th day after birth. At the same time muscle fiber necrosis was observed which increased with time. Electron microscopic investigations of the diseased heart muscle disclosed a marked interstitial oedema, swelling of the tubular system and sarcoplasmic reticulum, and degenerative changes in the mitochondria of individual myocardiocytes as early as the 2nd post-inoculation day. Simultaneously, an enlarged Golgi-apparatus and an increasing number of lysosomes, partially exhibiting acid phosphatase activity, was detected in the perinuclear region of ventricular myocardiocytes. On the 5th day after infection, viruses were detected either within single membrane vesicles, dispersed in cytoplasm or as aggregated clusters in the perinuclear region. These in vivo electron microscopic findings correspond with observations of virus propagation in cell-culture systems.     

Identification and expression of a murine cytomegalovirus early gene coding for an Fc receptor.

Several herpesviruses, including cytomegalovirus, induce receptors for the Fc domain of murine immunoglobulin G (IgG) molecules. Viral genes coding for these receptors have been characterized only for alphaherpesviruses. In this report, we describe a new approach that led to the identification of an Fc receptor (FcR) of murine cytomegalovirus (MCMV). The Fc fragment of IgG precipitated glycoproteins (gp) of 86 to 88 and 105 kDa from MCMV-infected cells. Deglycosylation by endoglycosidase F resulted in a protein with a molecular mass of 64 kDa. Injection of complete MCMV DNA or of DNA fragments, and the subsequent testing of cytoplasmic binding of IgG by immunofluorescence microscopy, was used to search for the coding region in the MCMV genome. The gene was located in the HindIII J fragment, map units 0.838 to 0.846, where an open reading frame of 1,707 nucleotides predicts a gp of 569 amino acids with a calculated molecular mass of 65 kDa. The sequence of this gp is related to those of the gE proteins of herpes simplex virus type 1 and varicella-zoster virus. The defined length of the mRNA, 1,838 nucleotides, was in agreement with that of a 1.9-kb RNA expressed throughout the replication cycle, starting at the early stages of infection. Expression of the gene fcr1 by recombinant vaccinia virus resulted in the synthesis of gp86/88 and gp105, each with FcR properties, and the correct identification of the gene encoding the FcR was confirmed by the DNA injection method.     

Effect of ultraviolet radiation on the microsporidian Octosporea muscaedomesticae with reference to protectants provided by the host Phormia regina

The effect of ultraviolet light on the microsporidian Octosporea muscaedomesticae in relation to infection in the adult black blowfly, Phormia regina, was investigated. A 30-Watt germicidal lamp, 253.7-nm wavelength, was used as source of uv light in five investigations. In addition, sunlight served as a uv source in two studies. Viable naked dried spores exposed to the uv lamp at a distance of 10 cm were killed after 15 min. Viable naked spores in an aqueous suspension were killed after 30 min of exposure to the uv lamp and after 3 hr of exposure to bright sunlight, respectively. Daily 30-min uv lamp exposures on living hosts harboring all life phases of the parasite did not interfere with the ensuing infection in the blowfly's midgut and the pathogen's developmental cycle. Spores harvested from uv-treated infected hosts were found to be as infective as spores retrieved from hosts not treated with uv. Spores contained in dried fecal droplets and exposed up to 3 hr to the uv lamp, or 12 hr to bright sunlight, respectively, remained infective. Addition of uric acid to a preparation of naked spores prior to 15- and 30-min uv irradiations yielded 100% infection in both host groups. A uv-protective function is ascribed to components provided by the host's tissues and feces.     

The nitrite-oxidizing community in activated sludge from a municipal wastewater treatment plant determined by fatty acid methyl ester-stable isotope probing

Metabolically-active autotrophic nitrite oxidizers from activated sludge were labeled with ¹³C-bicarbonate under exposure to different temperatures and nitrite concentrations. The labeled samples were characterized by FAME-SIP (fatty acid methyl ester-stable isotope probing). The compound cis-11-palmitoleic acid, which is the major lipid of the most abundant nitrite oxidizer in activated sludge, Candidatus Nitrospira defluvii, showed ¹³C-incorporation in all samples exposed to 3 mM nitrite. Subsequently, the lipid cis-7-palmitoleic acid was labeled, and it indicated the activity of a nitrite oxidizer that was different from the known Nitrospira taxa in activated sludge. The highest incorporation of cis-7-palmitoleic acid label was found after incubation with a nitrite concentration of 0.3 mM at 17 and 22 °C. While activity of Nitrobacter populations could not be detected by the FAME-SIP approach, an unknown nitrite oxidizer with the major lipid cis-9 isomer of palmitoleic acid exhibited ¹³C-incorporation at 28 °C with 30 mM nitrite. These results indicated flexibility of nitrite-oxidizing guilds in a complex community responding to different conditions. Labeled lipids so far not described for activated sludge-associated nitrifiers indicated the presence of unknown nitrite oxidizers in this habitat. The FAME-SIP-based information can be used to define appropriate conditions for the enrichment of nitrite-oxidizing guilds from complex samples.     

A multimedia tool for the informed consent of patients prior to gastric banding

Objective: Severe obesity is a clear indication for appropriate, effective weight loss therapy. One option is operative intervention, e.g., gastric banding. Risks of the operation and therapeutic alternatives need to be comprehensibly presented to the patient. The literature has shown that better informed consent is obtained using information presented in a multimedia/video‐based format. The current study developed and evaluated a multimedia program aimed at obtaining informed consent from obese patients before gastric banding. Research Methods and Procedure: An interactive multimedia program was developed with information about preoperative examinations, the operation itself, hospital stay, operative risks, alternative therapies, and the pathophysiology and health risks of obesity. Two groups (Group 1, n = 20, mean age 38 years, informed consent attained with conventional document information; Group 2, n = 20, mean age 37 years, informed consent attained with additional multimedia information) were interviewed regarding comprehensibility of the information presented, personal satisfaction, and anxiety levels during the informed consent process. Results: Group 2 showed significantly better (p < 0.05) understanding of the presented information and higher levels of satisfaction with the informed consent process. Anxiety levels did not significantly differ between the two groups. Discussion: Because patient satisfaction with the informed consent process and understanding of the presented information significantly improved, the multimedia program clearly benefits both surgeons and patients. Personal contact from the surgeon remains essential. High volumes of information presented in multimedia format do not alleviate patient anxiety, and personal contact may be beneficial.     

Bacteriophages of spirochetes

Historically, a number of bacteriophage-like particles have been observed in association with members of the bacterial order Spirochetales, the spirochetes. In the last decade, several spirochete bacteriophages have been isolated and characterized at the molecular level. We have recently characterized a bacteriophage of the Lyme disease agent, Borrelia burgdorferi, which we have designated phiBB-1. Here we review the history of the association between the spirochetes and their bacteriophages, with a particular emphasis on phiBB-1 and its prophage, the 32-kb circular plasmid family of B. burgdorferi.