23924379
Superdormant spores of Bacillus species have elevated wet-heat resistance and temperature requirements for heat activation.
Purified superdormant spores of Bacillus cereus, B. megaterium, and B. subtilis isolated after optimal heat activation of dormant spores and subsequent germination with inosine, d-glucose, or l-valine, respectively, germinate very poorly with the original germinants used to remove dormant spores from spore populations, thus allowing isolation of the superdormant spores, and even with alternate germinants. However, these superdormant spores exhibited significant germination with the original or alternate germinants if the spores were heat activated at temperatures 8 to 15 degrees C higher than the optimal temperatures for the original dormant spores, although the levels of superdormant spore germination were not as great as those of dormant spores. Use of mixtures of original and alternate germinants lowered the heat activation temperature optima for both dormant and superdormant spores. The superdormant spores had higher wet-heat resistance and lower core water content than the original dormant spore populations, and the environment of dipicolinic acid in the core of superdormant spores as determined by Raman spectroscopy of individual spores differed from that in dormant spores. These results provide new information about the germination, heat activation optima, and wet-heat resistance of superdormant spores and the heterogeneity in these properties between individual members of dormant spore populations.
1212219
Effects of Mn levels on resistance of Bacillus megaterium spores to heat, radiation and hydrogen peroxide.
AIMS
To determine the effects of Mn levels in Bacillus megaterium sporulation and spores on spore resistance.


METHODS AND RESULTS
Bacillus megaterium was sporulated with no added MnCl(2) and up to 1 mmol l(-1) MnCl(2). The resultant spores were purified and loosely bound Mn removed, and spore Mn levels were found to vary c. 100-fold. The Mn level had no effect on spore γ-radiation resistance, but B. megaterium spores with elevated Mn levels had higher resistance to UVC radiation (as did Bacillus subtilis spores), wet and dry heat and H(2)O(2). However, levels of dipicolinic acid and the DNA-protective α/β-type small, acid-soluble spore proteins were the same in spores with high and low Mn levels.


CONCLUSIONS
Mn levels either in sporulation or in spores are important factors in determining levels of B. megaterium spore resistance to many agents, with the exception of γ-radiation.


SIGNIFICANCE AND IMPACT OF THE STUDY
The Mn level in sporulation is an important factor to consider when resistance properties of B. megaterium spores are examined, and will influence the UV resistance of B. subtilis spores, some of which are used as biological dosimeters.
21780213
Interfacial and self-aggregation of binary mixtures of anionic and nonionic amphiphiles in aqueous medium.
Interfacial and bulk properties of sodium dodecyl sulfate (SDS), polyoxyethylene (20) sorbitan monooleate (Tween-80), and their binary mixtures in aqueous medium have been investigated using surface tension, conductance, and fluorescence measurements at different temperatures. The critical micelle concentration (CMC), counterion binding, polarity index, aggregation number, thermodynamics of interfacial adsorption, and micellization are evaluated. The entropic contribution is found to be the predominant factor in micelle formation. The aggregation number and the polarity index of the micelle interior estimated by the pyrene fluorescence technique show interesting temperature dependence. The size and composition of the mixed micelles vary with the total concentration. The micellar compositions, activities of the individual components in the mixed species, and intersurfactant interactions are also estimated following regular solution theory, excess thermodynamic functions, and a molecular thermodynamic model. The surfactant mixtures are found to be nonideal with a lower degree of counterion binding compared to the individual members. Mixed micelles are nonspherical in nature at all temperatures when the mole fraction (α) of the ionic part in mixtures is high but transform to spherical when α(SDS) is ≤0.50.
1788663
Hypertrophic cardiomyopathy with preexcitation: insights from noninvasive electrocardiographic imaging (ECGI) and catheter mapping.
UNLABELLED
Hypertrophic Cardiomyopathy and Preexcitation.


INTRODUCTION
Fasciculoventricular pathway has been described as an unusual variant of preexcitation. Electrocardiographic imaging (ECGI) is a novel imaging modality for noninvasive electroanatomic mapping of epicardial activation and repolarization.


CASE
We present a case of an 18-year-old male with hypertrophic cardiomyopathy (HCM) and an electrocardiogram (ECG)-based diagnosis of Wolff-Parkinson-White (WPW) syndrome, who underwent a noninvasive ECGI study to image ventricular activation, followed by an electrophysiology study (EPS). The ECGI electroanatomic isochrone map showed early activation of the epicardial aspect of the atrioventricular (A-V) groove and an aberrant posterior-base-to-apex progression of activation in the left ventricular (LV) epicardium. The EPS showed a likely fasciculoventricular pathway (FVP) without any inducible tachycardia.


CONCLUSION
While FVP has been described before, this is the first report of detailed quantitative three-dimensional characterization of electrical activation sequence of a heart with this type of preexcitation, using a novel noninvasive imaging modality (ECGI). In spite of abnormal ventricular activation, the EPS demonstrated that the FVP is not capable of supporting reentrant supraventricular tachycardia or rapidly conducted atrial fibrillation.
13798187
Spectroscopic, computational, and kinetic studies of the mu4-sulfide-bridged tetranuclear CuZ cluster in N2O reductase: pH effect on the edge ligand and its contribution to reactivity.
A combination of spectroscopy and density functional theory (DFT) calculations has been used to evaluate the pH effect at the CuZ site in Pseudomonas nautica (Pn) nitrous oxide reductase (N2OR) and Achromobacter cycloclastes (Ac) N2OR and its relevance to catalysis. Absorption, magnetic circular dichroism, and electron paramagnetic resonance with sulfur K-edge X-ray absorption spectra of the enzymes at high and low pH show minor changes. However, resonance Raman (rR) spectroscopy of PnN2OR at high pH shows that the 415 cm-1 Cu-S vibration (observed at low pH) shifts to higher frequency, loses intensity, and obtains a 9 cm-1 18O shift, implying significant Cu-O character, demonstrating the presence of a OH- ligand at the CuICuIV edge. From DFT calculations, protonation of either the OH- to H2O or the mu4-S2- to mu4-SH- would produce large spectral changes which are not observed. Alternatively, DFT calculations including a lysine residue at an H-bonding distance from the CuICuIV edge ligand show that the position of the OH- ligand depends on the protonation state of the lysine. This would change the coupling of the Cu-(OH) stretch with the Cu-S stretch, as observed in the rR spectrum. Thus, the observed pH effect (pKa approximately 9.2) likely reflects protonation equilibrium of the lysine residue, which would both raise E degrees and provide a proton for lowering the barrier for the N-O cleavage and for reduction of the [Cu4S(im)7OH]2+ to the fully reduced 4CuI active form for turnover.
31421212
New regulators of NF-κB in inflammation
Research on the biological function of nuclear factor-κB (NF-κB), a key mediator of inducible transcription in the immune system, has traditionally focused on its role in the initiation of innate and adaptive immune responses. These studies have largely concentrated on the mechanisms of signalling that lead to NF-κB activation and on the positive role of NF-κB in both physiological immunity and pathological inflammation. More recently, there has been growing interest in the mechanisms that directly regulate the NF-κB transcriptional programmes. As a result, several new NF-κB regulatory components have been identified and some of the known components have been assigned new roles. In this Review, we discuss these new insights into the regulation of NF-κB.
19814204
Comparative diagnostic potentiality of ELISA and dot-ELISA in prepatent diagnosis of experimental Fasciola gigantica infection in cattle.
A glycoprotein (27 kDa) was isolated from crude somatic antigen of Fasciola gigantica by two steps affinity chromatography and was used in early detection of experimental fasciolosis in cattle by indirect ELISA and in dot-ELISA formats. Although, anti-27 kDa antibodies could be detected after 3 weeks post infection (WPI) by dot - ELISA which was one week later than indirect ELISA. The test, dot-ELISA, was more convenient in field application. By the test (dot-ELISA) the infection could be equally detected in animals infected with 100, 200 and 300 metacercariae of F. gigantica with high sensitivity. Further, the antigen (27 kDa) was not found to react with goat sera infected with Paramphistomum epiclitum, which are giving strong reaction to homologous immature and mature fluke antigens of P. epiclitum.