In vitro characterization of FlgB, FlgC, FlgF, FlgG, and FliE, flagellar basal body proteins of Salmonella.

The bacterial flagellar basal body is a rotary motor. It spans the cytoplasmic and outer membranes and drives rapid rotation of a long helical filament in the cell exterior. The flagellar rod at its central axis is a drive shaft that transmits torque through the hook to the filament to propel the bacterial locomotion. To study the structure of the rod in detail, we have established purification procedures for Salmonella rod proteins, FlgB, FlgC, FlgF, FlgG, and also for FliE, a rod adapter protein, from an Escherichia coli expression system. While FlgF was highly soluble, FlgB, FlgC, FlgG and FliE tended to self or cross-aggregate into fibrils in solutions at neutral pH or below, at high ionic strength, or at high protein concentration. These aggregates were characterized to be beta-amyloid fibrils, unrelated to the rod structure formed in vivo. Under non-aggregative conditions, no protein-protein interactions were detected between any pairs of these five proteins, suggesting that their spontaneous, template-free polymerization is strongly suppressed. Limited proteolyses showed that FlgF and FlgG have natively unfolded N and C-terminal regions of about 100 residues in total just as flagellin does, whereas FlgB, FlgC and FliE, which are little over 100 residues long, are unfolded in their entire peptide chains. These results together with other data indicate that all of the ten flagellar axial proteins share structural characteristics and folding dynamics in relation to the mechanism of their self-assembly into the flagellar axial structure.

Anti-diabetic effects of lactic acid bacteria in normal and type 2 diabetic mice.

The antidiabetic effects of lactic acid bacteria were investigated using mice. In Experiment 1, normal ICR mice were loaded with sucrose or starch with or without viable Lactobacillus rhamnosus GG cells. GG significantly inhibited postprandial blood glucose levels when administered with sucrose or starch. In Experiment 2, KK-A(y) mice, a model of genetic type 2 diabetes, were given a basal diet containing viable GG cells or viable Lactobacillus delbrueckii subsp. bulgaricus cells for 6 weeks. Viable GG cells significantly inhibited fasting blood glucose, postprandial blood glucose in a glucose tolerance test and HbA1c. Such effects were not shown by viable L. bulgaricus cells. In Experiment 3, the KK-A(y) mice were given a basal diet containing viable GG cells or heat-treated GG cells for 3 weeks. The viable GG cells significantly suppressed fasting blood glucose and impaired glucose tolerance, but the heat-treated GG showed no effects. These results demonstrated that GG decreased the postprandial blood glucose in ICR mice, and that the antidiabetic activity of lactic acid bacteria on the KK-A(y) mice differed depending on the bacterial strain and whether the bacterium is viable when it arrives in the intestine. In the present study, we conclude that the antidiabetic activity may result from continuous inhibition of the postprandial blood glucose through suppression of glucose absorption from the intestine. These findings indicate that specific strains of lactic acid bacterium can be expected to be beneficial for the management of type 2 diabetes.

Synthesis and spectroscopic studies of composite gold nanorods with a double-shell structure composed of spacer and cyanine dye J-aggregate layers.

The composite gold nanorods (Au NRs) having a double-shell structure composed of Au NR (core), spacer layer (inner shell), and J-aggregate (JA) layer (outer shell) have been synthesized to examine the spectroscopic properties of the hybrid system in which the localized surface plasmon is coupled with the molecular exciton of JA. The spacer layer consisting of N,N,N-trimethyl(11-mercaptoundecyl)ammonium chloride plays a significant role in the formation of JA shell for several kinds of cyanine dyes. The absorption spectra of composite NRs are characterized by a distinct dip near the J-band when the plasmon energy of Au core is close to the exciton energy of JA shell, whereas a normal J-band peak appears when two energies are widely different from each other. The gradual change from the dip type to peak type absorption was observed when the plasmon energy was modulated by varying the aspect ratio of Au NR. Furthermore, composite NRs with thicker spacer layers have been fabricated by inserting the multilayer shell of polyelectrolytes between TMA and JA layers. They exhibited an alteration of the spectral line shape from the dip type to peak type with increase in the thickness of spacer layer. These observations have been interpreted in terms of the strength of the exciton-plasmon coupling, which is sensitive to the configuration of composite NRs as well as the relative difference between plasmon and exciton energies.

Clinical effect of vitamin D3 analogues is not inactivated by subsequent UV exposure.

BACKGROUND: Combining phototherapy with topical vitamin D3 analogues is a useful therapy for the treatment of psoriasis by reducing the cumulative UV dose required for clearance of lesions. Experimental investigations demonstrated that calcipotriol is degraded by UV radiation, and suggested that calcipotriol should be applied after phototherapy but not immediately before. METHODS: Calcipotriol or maxacalcitol ointment was topically applied to psoriatic plaques of six patients immediately before or after phototherapy on the right or left side of the body, respectively. RESULTS: Topical application of vitamin D3 analogues either before or after irradiation by psoralen and UVA radiation (PUVA) or narrow-band (NB)-UVB showed exactly similar effects in all patients. CONCLUSION: Therapeutic effects of vitamin D3 analogues are not clinically inactivated by subsequent irradiation with PUVA or NB-UVB phototherapy.

Construction of hybrid photosynthetic units using peripheral and core antennae from two different species of photosynthetic bacteria: detection of the energy transfer from bacteriochlorophyll a in LH2 to bacteriochlorophyll b in LH1.

Typical purple bacterial photosynthetic units consist of supra-molecular arrays of peripheral (LH2) and core (LH1-RC) antenna complexes. Recent atomic force microscopy pictures of photosynthetic units in intact membranes have revealed that the architecture of these units is variable (Scheuring et al. (2005) Biochim Bhiophys Acta 1712:109-127). In this study, we describe methods for the construction of heterologous photosynthetic units in lipid-bilayers from mixtures of purified LH2 (from Rhodopseudomonas acidophila) and LH1-RC (from Rhodopseudomonas viridis) core complexes. The architecture of these reconstituted photosynthetic units can be varied by controlling ratio of added LH2 to core complexes. The arrangement of the complexes was visualized by electron-microscopy in combination with Fourier analysis. The regular trigonal array of the core complexes seen in the native photosynthetic membrane could be regenerated in the reconstituted membranes by temperature cycling. In the presence of added LH2 complexes, this trigonal symmetry was replaced with orthorhombic symmetry. The small lattice lengths for the latter suggest that the constituent unit of the orthorhombic lattice is the LH2. Fluorescence and fluorescence-excitation spectroscopy was applied to the set of the reconstituted membranes prepared with various proportions of LH2 to core complexes. Remarkably, even though the LH2 complexes contain bacteriochlorophyll a, and the core complexes contain bacteriochlorophyll b, it was possible to demonstrate energy transfer from LH2 to the core complexes. These experiments provide a first step along the path toward investigating how changing the architecture of purple bacterial photosynthetic units affects the overall efficiency of light-harvesting.

Anesthetic management of bidirectional cavopulmonary shunt in a patient with pulmonary atresia with intact ventricular septum associated with sinusoidal communications.

Pulmonary atresia with intact ventricular septum (PAIVS) is sometimes associated with coronary artery anomalies, including right ventricle (RV)-to-coronary artery fistulas (sinusoidal communications), coronary artery stenoses, and coronary artery occlusions. In some cases, the coronary circulation depends entirely or partly on the desaturated systemic venous blood supply from the RV. Under these circumstances, decompression of the RV can result in fatal myocardial ischemia. A 6-month-old boy, diagnosed with PAIVS associated with sinusoidal communications, underwent a bidirectional cavopulmonary shunt procedure under venoarterial cardiopulmonary bypass (CPB). During CPB, to prevent RV decompression, we maintained right atrial pressure above 5 mmHg and used a pump perfusion rate of 30%-40% of the calculated value based on body surface area. Although electrocardiography showed slight ST depression and bradycardia, myocardial contractility after weaning from CPB was adequate to maintain the circulation with the administration of dobutamine and atrial pacing. In patients with PAIVS and RV-dependent coronary circulation, it is important to maintain coronary artery perfusion throughout the period of anesthesia.