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Facklamia ignava sp. nov., isolated from human clinical specimens.

Two strains of a hitherto-undescribed gram-positive, catalase-negative coccus isolated from human sources were characterized by phenotypic and molecular taxonomic methods. Comparative 16S rRNA gene sequencing studies demonstrated that the unknown strains are genealogically identical and constitute a new line close to, but distinct from, Facklamia hominis. The unknown bacterium was readily distinguished from F. hominis by biochemical tests and electrophoretic analysis of whole-cell proteins. On the basis of phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Facklamia ignava sp. nov. The type strain of Facklamia ignava is CCUG 37419.

Aged↗

Facklamia languida sp. nov., isolated from human clinical specimens.

Three strains of a gram-positive catalase-negative, facultatively anaerobic coccus-shaped organism originating from human clinical samples were characterized by phenotypic and molecular taxonomic methods. Sequencing of genes encoding 16S rRNA showed that the strains are phylogenetically closely related (99.9 to 100% sequence similarity) and represent a new subline within the genus Facklamia. The unknown bacterium was readily distinguished from all currently described species of the genus Facklamia (viz., Facklamia hominis, Facklamia ignava, and Facklamia sourekii) by biochemical tests and electrophoretic analysis of whole-cell proteins. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium be classified as Facklamia languida sp. nov. The type strain of F. languida is CCUG 37842.

Bacillaceae↗

Effects of intravitreal corticosteroids in the treatment of Bacillus cereus endophthalmitis.

OBJECTIVE: To investigate whether intravitreal corticosteroid therapy reduces the extent of inflammatory intraocular tissue damage caused by Bacillus cereus endophthalmitis. METHODS: New Zealand white rabbits were inoculated with 1 x 10(6) B cereus organisms and randomized to receive no treatment (control eyes; n=14), intravitreal vancomycin hydrochloride (n=13), or a combination of intravitreal vancomycin and dexamethasone sodium phosphate (n=13) after 24 hours. The eyes were examined and graded for clinical signs of infection and inflammation on days 7 and 14, followed by enucleation for histopathologic analysis. RESULTS: Both treated groups had significantly less clinical sequelae than controls on day 7. By day 14, eyes given combination treatment had significantly less clinically graded corneal (P=.03) and conjunctival (P=.007) inflammation than eyes treated with vancomycin. Histopathologic analysis revealed a significant decrease in inflammatory changes between all treated eyes and controls at day 14. The only statistically significant difference between eyes given combination treatment and eyes given vancomycin alone was in the retina (P=.03). CONCLUSIONS: Intravitreal corticosteroids may enhance the recovery from B cereus endophthalmitis when given in conjunction with intravitreal antibiotics. The beneficial effect of corticosteroids is noted clinically, but not histologically, by day 14 after single-dose treatment in rabbits. CLINICAL RELEVANCE: This study provides evidence that the use of intravitreal corticosteroids with antibiotics for the treatment of B cereus endophthalmitis may lead to an improvement compared with the use of antibiotics alone. Arch Ophthalmol. 2000;118:803-806

Animals↗

Circular permutants in beta-glucosidases (family 3) within a predicted double-domain topology that includes a (beta/alpha)8-barrel.

By predicting the general secondary structure for beta-glucosidases (family 3), in conjunction with existing knowledge of the circular permutants present in B. fibrisolvens and R. albus, we were able to find the canonical elements of the secondary structure. The way these elements are linked suggests that there is a double-domain topology made up of a (beta/alpha)8-barrel domain and a "mainly all-beta" domain. A number of already known conserved motifs are located within (or near) the C-terminal part of the putative parallel beta-strands of the (bet/alpha)8-barrel, which is consistent with what is known about the location of catalytical sites for enzymes that have this domain topology. Within the circular permutants, two beta/alpha units are located at the N-terminal part of the molecule, whereas the other six beta/alpha units are located at the C-terminal end. In this way, the circular permutants can be seen to have a putative discontinuous double-domain topology.

Amino Acid Sequence↗

Fatal Bacillus cereus sepsis following resolving neutropenic enterocolitis during the treatment of acute leukemia.

Bacillus cereus is increasingly being acknowledged as a serious bacterial pathogen in immunosuppressed hosts. We report a case of fatal B. cereus sepsis in a patient with newly diagnosed acute leukemia following resolving neutropenic enterocolitis. Gastrointestinal complaints are common during induction chemotherapy, yet some antimicrobial coverage suitable for generalized neutropenia is not optimal for the eradication of B. cereus. This case demonstrates that, in the neutropenic patient with gastrointestinal complaints or in the setting of resolving neutropenic enterocolitis, it is important to anticipate possible B. cereus infection and sepsis.

Adult↗

Characterization of esterase activity in Geobacillus sp. HBB-4.

A thermophilic esterase producing bacterium (Bacillus sp. 4), recently isolated from Alangüllü thermal spring in Aydin (Turkey), was analyzed using 16S rRNA and classified as Geobacillus sp. HBB-4, most closely related to Bacillus sp. BGSC W9A59 (0.70% sequence divergence) which belongs to the newly described genus Geobacillus. The effects of several chemicals on the activity of thermostable esterase from Geobacillus sp. HBB-4 were examined. Among the various metal ions tested, esterase activity was enhanced by Mn(+2) and Ni(+2), but was inhibited by Hg(+2) and Cu(+2), whereas Ca(+2), Mg(+2) and Co(+2) had no effect. In addition, other metal ions studied have caused a slight inhibition on the esterase activity. EDTA partially inhibited the HBB-4 esterase. The activator metal ions, Mn(+2) and Ni(+2) have restored partial inhibition of EDTA. The activity of HBB-4 esterase was inhibited by ionic detergents while non-ionic detergents activated the enzyme. However, a zwitterionic detergent, CHAPS, has caused a slight inhibition in the enzyme activity. HBB-4 esterase activity was inhibited at the high concentrations of all the organic solvents tested in the present study. However, 50% final concentration of DMSO increased the enzyme activity about 7%. The HBB-4 esterase has shown more than about 50% of activity in the presence of ethanol and methanol solutions. These characteristics of the enzyme along with its significant thermostability make the Geobacillus sp. HBB-4 esterase a potent candidate for future industrial applications.

Bacillaceae↗

Metal accumulation by bacteria with particular reference to dissimilatory sulphate-reducing bacteria.

Dissimilatory sulphate-reducing bacteria, genera Desulfovibrio and Desulfotomaculum, exhibit a superior ability, over assimilatory organisms, to extract three amounts of metals from culture media. This property does not appear to be solely a function of the presence of H2S. In media containing elevated amounts of Fe, electron dense particles, provisionally identified as FeS, are deposited within the cells of dissimilatory bacteria.

Bacillaceae↗

Green polymers from Geobacillus thermodenitrificans DSM465--candidates for molecularly imprinted materials.

Novel molecular recognition materials were prepared from water soluble proteins from thermophile G. thermodenitrificans DSM465 by an alternative molecular imprinting method. Water soluble proteins from G. thermodenitrificans DSM465 were converted into the molecularly imprinted materials by adopting 9-EA as a print molecule. The molecularly imprinted protein membranes recognized As in preference to Gs. The adsorption isotherms led to the conclusion that molecular recognition sites toward As were constructed by the presence of 9-EA during the membrane preparation process. The affinity constant between As and the molecular recognition site thus constructed was determined to be 1.75 x 10(5) mol(-1) dm(3). The results obtained in the present study suggest that water soluble proteins from G. thermodenitrificans DSM465 is one of environmentally-friendly 'green' polymers to be converted into molecular recognition materials by applying an alternative molecular imprinting method.

Adsorption↗

Proteomic analysis of cold adaptation in a Siberian permafrost bacterium--Exiguobacterium sibiricum 255-15 by two-dimensional liquid separation coupled with mass spectrometry.

Bacterial cold adaptation in Exiguobacterium sibiricum 255-15 was studied on a proteomic scale using a 2-D liquid phase separation coupled with MS technology. Whole-cell lysates of E. sibiricum 255-15 grown at 4 degrees C and 25 degrees C were first fractionated according to pI by chromatofocusing (CF), and further separated based on hydrophobicity by nonporous silica RP HPLC (NPS-RP-HPLC) which was on-line coupled with an ESI-TOF MS for intact protein M(r) measurement and quantitative interlysate comparison. Mass maps were created to visualize the differences in protein expression between different growth temperatures. The differentially expressed proteins were then identified by PMF using a MALDI-TOF MS and peptide sequencing by MS/MS with a MALDI quadrupole IT TOF mass spectrometer (MALDI-QIT-TOF MS). A total of over 500 proteins were detected in this study, of which 256 were identified. Among these proteins 39 were cold acclimation proteins (Caps) that were preferentially or uniquely expressed at 4 degrees C and three were homologous cold shock proteins (Csps). The homologous Csps were found to be similarly expressed at 4 degrees C and 25 degrees C, where these three homologous Csps represent about 10% of the total soluble proteins at both 4 degrees C and 25 degrees C.

Adaptation, Physiological↗

Multidimensional analysis of the insoluble sub-proteome of Oceanobacillus iheyensis HTE831, an alkaliphilic and halotolerant deep-sea bacterium isolated from the Iheya ridge.

We report the first proteomic analysis of the insoluble sub-proteome of the alkaliphilic and halotolerant deep-sea bacterium Oceanobacillus iheyensis HTE831. A multidimensional gel-based and gel-free analysis was utilised and a total of 4352 peptides were initially identified by automated MS/MS identification software. Automated curation of this list using PROVALT reduced our peptide list to 467 uniquely identified peptides that resulted in the positive identification of 153 proteins. These identified proteins were functionally classified and physiochemically characterised. Of 26 proteins identified as hypothetical conserved, we have assigned function to all but four. A total of 41 proteins were predicted to possess signal peptides. In silico investigation of these proteins allowed us to identify three of the five bacterial classes of signal peptide, namely: (i) twin-arginine translocation; (ii) Sec-type and (iii) lipoprotein transport. Our proteomic strategy has also allowed us to identify, at neutral pH, a number of proteins described previously as belonging to two putative transport systems believed to be of importance in the alkaliphilic adaptation of O. iheyensis HTE831.

Amino Acid Sequence↗

Crystallization and preliminary X-ray crystallographic analysis of squalene-hopene cyclase from Alicyclobacillus acidocaldarius.

The membrane-associated protein squalene-hopene cyclase from Alicyclobacillus acidocaldarius was overexposed in Escherichia coli and purified by ion exchange and gel permeation chromatography. Crystals of three interrelated forms were grown by vapor diffusion under identical conditions. The crystals diffract to about 2.3 A resolution, but they are unstable in the X-ray beam. An interpretable heavy-atom derivative was obtained.

Bacillaceae↗

Cloning, overexpression, and properties of a new thermophilic and thermostable esterase with sequence similarity to hormone-sensitive lipase subfamily from the archaeon Archaeoglobus fulgidus.

A new esterase gene from the hyperthermophilic archaeon Archaeoglobus fulgidus, reported to show homology with the mammalian hormone-sensitive lipase (HSL)-like group of the esterase/lipase family, was cloned by means of the polymerase chain reaction from the A. fulgidus genome. In order to compare the biochemical properties of this putative hyperthermophilic enzyme with those of the homologous, thermophilic member of HSL group, namely Alicyclobacillus (formerly Bacillus) acidocaldarius esterase 2 (EST2), an overexpression system in Escherichia coli was established. The recombinant protein, expressed in soluble and active form at 20 mg/liter of E. coli culture, was purified to homogeneity and characterized. The enzyme, a 35.5-kDa monomeric protein, was demonstrated to be a B"-type carboxylesterase (EC 3.1.1.1) on the basis of substrate specificity and the action of inhibitors. Among the p-nitrophenyl (PNP) esters tested the best substrate was PNP-hexanoate with K(m) and k(cat) values of 11 +/- 3 microM (mean +/- SD, n = 3) and 1014 +/- 38 s(-1) (mean +/- SD, n = 3), respectively, at 70 degrees C and pH 7.1. Inactivation by diethylpyrocarbonate, phenylmethylsulfonylfluoride, diisopropylfosfofluoridate (DFP), and physostigmine, as well as labeling with [(3)H]DFP, supported our previous suggestion of a catalytic triad made up of Ser(160)-His(285)-Asp(255). The sequence identity with the thermostable A. acidocaldarius EST2 was 42.5%. The enzyme proved to be much more stable than its Alicyclobacillus counterpart. The conformational dynamics of the two proteins were investigated by frequency-domain fluorometry and anisotropy decay and the activity/stability/temperature relationship was discussed.

Amino Acid Sequence↗

Histopathological and histochemical changes in honeybee larvae (Apis mellifera L.) after infection with Bacillus larvae, the causative agent of American foulbrood disease.

Morphological, histochemical and cytochemical changes were examined in honeybee larvae after infection with the bacterium Bacillus larvae. The results indicate cell necrosis in the midgut epithelium accompanied by increasing cell vacuolization and nuclear pyknosis following per os inoculation with B. larvae. Many autolysosomes were positive for acid phosphatase. Non-vacuolar acid phosphatase activity was also found in lysed cell compartments. No such activity was found in regenerative epithelial cells. Degradation of haemocytes, salivary glands and other tissues was also observed. Histochemical analyses after per cutaneous inoculation with B. larvae of three- and five-day-old honeybee larvae show intense non-vacuolar acid phosphatase activity followed by disintegration of infected salivary glands, epithelial cell cytoplasm and haemocytes.

Acid Phosphatase↗

In situ localization of heat-shock and histone proteins in honey-bee (Apis mellifera l.) larvae infected with Paenibacillus larvae.

The immunohistochemical localization of the heat shock proteins (Hsp70 and Hsp90) and histone protein in healthy and Paenibacillus larvae infected honeybee (Apis mellifera L.) larvae has been studied. Hsp70 was found in the nuclei and the cytoplasm of infected midgut, salivary gland cells and haemocytes, but not in uninfected larvae. Hsp90 was localized in both infected and uninfected cells. Exposed histone proteins were localized in the nuclei of dying uninfected cells undergoing programmed cell death. The distribution of histone protein in uninfected cells of midgut, salivary gland, and other tissues was nuclear and indicative of normal programmed cell death at levels between 1 and 5%. After applying histone protein antibodies to P. larvae infected honeybee larvae, the DAB based reaction product was located in the nuclei or immediate surroundings of all larval cells. The Hsp70, Hsp90 and histone protein distribution patterns are discussed in relation to the morphological, cytochemical and immunocytochemical characteristics of programmed cell death and pathological necrosis. Results produced by methyl green-pyronin staining confirm an elevation of RNA levels in normal programmed cell death and a reduced staining for RNA in necrotic infected cells.

Animals↗