bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Lipolytic Enzyme, YcsK (LipC), Located in the Spore Coat of
Bacillus subtilis
, Is Involved in Spore Germination
Authors: Masayama Atsushi , Kuwana Ritsuko , Takamatsu Hiromu , Hemmi Hisashi , Yoshimura Tohru , Watabe Kazuhito , Moriyama Ryuichi 
Published: January 2007

ABSTRACT

The predicted amino acid sequence of
Bacillus subtilis ycsK
exhibits similarity to the GDSL family of lipolytic enzymes. Northern blot analysis showed that
ycsK
mRNA was first detected from 4 h after the onset of sporulation and that transcription of
ycsK
was dependent on SigK and GerE. The fluorescence of the YcsK-green fluorescent protein fusion protein produced in sporulating cells was detectable in the mother cell but not in the forespore compartment under fluorescence microscopy, and the fusion protein was localized around the developing spores dependent on CotE, SafA, and SpoVID. Inactivation of the
ycsK
gene by insertion of an erythromycin resistance gene did not affect vegetative growth or spore resistance to heat, lysozyme, or chloroform. The germination of
ycsK
spores in a mixture of
l
-asparagine,
d
-glucose,
d
-fructose, and potassium chloride and LB medium was also the same as that of wild-type spores, but the mutant spores were defective in
l
-alanine-stimulated germination. In addition, zymogram analysis demonstrated that the YcsK protein heterologously expressed in
Escherichia coli
showed lipolytic activity. We therefore propose that
ycsK
should be renamed
lipC
. This is the first study of a bacterial spore germination-related lipase.
The
rbmBCDEF
Gene Cluster Modulates Development of Rugose Colony Morphology and Biofilm Formation in
Vibrio cholerae
Authors: Fong Jiunn C. N. , Yildiz Fitnat H. 
Published: January 2007

ABSTRACT

Vibrio cholerae
, the causative agent of cholera, can undergo phenotypic variation generating rugose and smooth variants. The rugose variant forms corrugated colonies and well-developed biofilms and exhibits increased levels of resistance to several environmental stresses. Many of these phenotypes are mediated in part by increased expression of the
vps
genes, which are organized into
vps-
I and
vps-
II coding regions, separated by an intergenic region. In this study, we generated in-frame deletions of the five genes located in the
vps
intergenic region, termed
rbmB
to -
F
(
r
ugosity and
b
iofilm structure
m
odulators B to F) in the rugose genetic background, and characterized the mutants for rugose colony development and biofilm formation. Deletion of
rbmB
, which encodes a protein with low sequence similarity to polysaccharide hydrolases, resulted in an increase in colony corrugation and accumulation of exopolysaccharides relative to the rugose variant. RbmC and its homolog Bap1 are predicted to encode proteins with carbohydrate-binding domains. The colonies of the
rbmC bap1
double deletion mutant and
bap1
single deletion mutant exhibited a decrease in colony corrugation. Furthermore, the
rbmC bap1
double deletion mutant was unable to form biofilms at the air-liquid interface after 2 days, while the biofilms formed on solid surfaces detached readily. Although the colony morphology of
rbmDEF
mutants was similar to that of the rugose variant, their biofilm structure and cell aggregation phenotypes were different than those of the rugose variant. Taken together, these results indicate that
vps
intergenic region genes encode proteins that are involved in biofilm matrix production and maintenance of biofilm structure and stability.
Interrelationships between Colonies, Biofilms, and Planktonic Cells of
Pseudomonas aeruginosa
Authors: Mikkelsen H. , Duck Z. , Lilley K. S. , Welch M. 
Published: January 2007

ABSTRACT

Pseudomonas aeruginosa
is a gram-negative bacterium and an opportunistic human pathogen that causes chronic infections in immunocompromised individuals. These infections are hard to treat, partly due to the high intrinsic resistance of the bacterium to clinically used antibiotics and partly due to the formation of antibiotic-tolerant biofilms. The three most common ways of growing bacteria in vitro are as planktonic cultures, colonies on agar plates, and biofilms in continuous-flow systems. Biofilms are known to express genes different from those of planktonic cells, and biofilm cells are generally believed to closely resemble planktonic cells in stationary phase. However, few, if any, studies have examined global gene expression in colonies. We used a proteomic approach to investigate the interrelationships between planktonic cells, colonies, and biofilms under comparable conditions. Our results show that protein profiles in colonies resemble those of planktonic cells. Furthermore, contrary to what has been reported previously, the protein profiles of biofilms were found to more closely resemble those of exponentially growing planktonic cells than those of planktonic cells in the stationary phase. These findings raise some intriguing questions about the true nature of biofilms.
Immunohistochemical study of nuclear factor-κB activity and interleukin-8 abundance in oesophageal adenocarcinoma; a useful strategy for monitoring these biomarkers
Authors: Jenkins G J S , Mikhail J , Alhamdani A , Brown T H , Caplin S , Manson J M , Bowden R , Toffazal N , Griffiths A P , Parry J M , Baxter J N 
Published: January 2007

Aims:To determine if immunohistochemistry (IHC) could be used to monitor nuclear factor-κB (NF-κB) activity in oesophageal adenocarcinoma and pre-malignant (Barrett’s) oesophageal tissues, relative to normal oesophageal mucosa. The pro-inflammatory cytokine interleukin-8 (IL-8), a transcriptional target of NF-κB, was also studied to better understand NF-κB functionality; its RNA and protein levels were assessed in oesophageal tissues.Methods:IHC was employed using an antibody against the nuclear localisation sequence (NLS) of the p65 subunit as well as an antibody against IL-8. To assess NF-κB function, changes in gene expression of NF-κB controlled genes (IL-8 and I-κB) were also assessed in the histological sequence using real-time PCR. More global expression changes were also studied using membrane arrays.Results:IHC was effective at monitoring overall NF-κB activity and IL-8 abundance. This method also allowed NF-κB activity and IL-8 abundance to be pinpointed in specific cell types. There were significant increases in nuclear NF-κB activity and IL-8 abundance across the histological series. Gene expression analysis also showed consistent up-regulation of IL-8, confirming the IHC data and showing enhanced transcriptional NF-κB activity. I-κB (another NF-κB target) showed down-regulation in dysplastic and adenocarcinoma tissues. Down-regulation of I-κB gene expression may partly explain increased NF-κB activity.Conclusion:IHC, using antibodies against the NLS of p65, may be useful in monitoring overall NF-κB activity in oesophageal tissues. As IHC is amenable to high-throughput screening (whereas traditional electrophoretic mobility shift assay methods are not), this may lead to the development of a better screening tool for early cancer risk.
Papermaking properties of the ECF-bleached kraft pulps from first-thinning Scots pine (Pinus sylvestris L.)
Authors: Rautiainen Riikka , Alén Raimo 
Published: January 2007

Abstract
First-thinning Scots pine (Pinus sylvestris) and the outer (containing long fibers) and inner (containing short fibers) parts of its stem wood were delignified on a laboratory scale by kraft pulping followed by oxygen-alkali delignification and bleaching with D0(EO)D1(EP)D2. The aim was to evaluate the potential use of the bleached pulps as reinforcing material in various mechanical and chemical pulps. The physical and optical properties of the pulps indicated that only the “outer part pulp”, with rather similar properties to those of a reference softwood kraft pulp, seemed suitable for this purpose. In contrast, materials from first-thinning stem wood and its inner part resulted in lower yields as early as the kraft pulping stage. Rather mediocre strength properties were obtained, but the bleached kraft pulps prepared from the two first thinning-based materials had good optical properties.
Syntheses and properties of liquefied products of ozone treated wood/epoxy resins having high wood contents
Authors: Asano Toshiyuki , Kobayashi Masahiko , Tomita Bunichiro , Kajiyama Mikio 
Published: January 2007

Abstract
Liquefied products with high wood content were prepared by pretreating wood with ozone before liquefaction. As a result, the ratio of wood to polyhydric alcohol (W/P ratio) used as solvent could be increased to 2:1. Resin blends were prepared by mixing liquefied products with ethylene glycol diglycidyl ether (EGDGE, water-soluble) and diglycidyl ether of bisphenol A (DGEBA, oily consistency). The wood content of the resin blend could be increased to 53%. The resins were cured by citric acid or triethylene tetramine (TETA), and their mechanical properties were evaluated. Dynamic mechanical measurements revealed that the former had higher glass transition temperatures than the latter. It was found that the resin with DGEBA cured by citric acid had almost the same level of tensile strength as commercial plastics.
Dynamic mechanical analysis of dry wood: Linear viscoelastic response region and effects of minor moisture changes
Authors: Sun Nanjian , Das Sudipto , Frazier Charles E. 
Published: January 2007

AbstractThe dynamic mechanical analysis (DMA) of wood with moisture content (MC) below 1% has not yet been described. Aiming at this low MC range, the linear viscoelastic response region (LVR) of thoroughly dried wood was studied in single-cantilever bending. The LVR limit was determined as a function of grain orientation and temperature using yellow-poplar (Liriodendron tulipifera) and southern yellow pine(Pinusspp.). The LVR limit for dry wood ranged from approximately 0.03% to 0.16% strain. The LVR limit was greater for bending perpendicular to the grain than for parallel to the grain, suggesting that DMA signal quality would be better in the former case. Southern pine generally exhibited a greater LVR limit than yellow-poplar. The LVR anisotropy was greater in yellow-poplar than in southern pine. These findings suggest that detailed LVR analysis might be useful for wood analysis, or at least that regular LVR analysis is required for reliable wood DMA. The effects of wood moisture changes (between 0% and 1%) were observed in low-temperature secondary relaxations, consistent with the previous findings of others. Yellow-poplar specimens exhibited a significant storage modulus increase over a 250°C temperature range when specimen moisture increased from 0% to ∼0.7%.
Penetration of amino-silicone micro- and macro-emulsions into Scots pine sapwood and the effect on water-related properties
Authors: Weigenand Oliver , Militz Holger , Tingaut Philippe , Sèbe Gilles , de Jeso Bernard , Mai Carsten 
Published: January 2007

Abstract
An amino-silicone in the form of a micro- and a macro-emulsion (average particle size 40 and 120 nm, respectively) was tested in impregnation of solid wood. During vacuum-pressure impregnation, the uptake of 5% emulsions was only slightly reduced compared to water up-take. At 15% concentration, a significant reduction in emulsion uptake was observed, particularly in the radial and tangential directions of the wood. The penetration of silicone into the cell wall was dependent on the particle size of the emulsion. Applied as a macro-emulsion, a maximum of only 14% of the total silicone penetrated the cell wall, whereas 25–35% of the silicone was found in the cell wall when applied as a micro-emulsion. The degree of cell wall penetration of silicone for the micro-emulsion was confirmed by X-ray micro-analysis (SEM-EDX). The penetrated silicone caused bulking and dimensional stability. 1H NMR relaxometry T
2 distributions were determined for dried and moisture-conditioned wood samples. The silicone-treated specimens displayed spin-spin interactions of protons from water and silicones (or their emulsifiers). Conditioning of samples at 25°C and 65% relative humidity appeared to cause a decrease in the mobility of the non-water protons of the silicone and/or emulsifier. Freezing to -5°C caused separation of protons from bound water and from the silicone at low relaxation times. It is assumed that treatment with the micro-emulsion reduced water sorption due to micro-pore blocking in the cell wall. The formation of a sandwich complex is postulated, which comprises cell wall polymers, water molecules and a layer of silicone.
Search for a relationship between stress wave velocity and internal stresses in eucalypts and radiata pine
Authors: Chauhan Shakti S. , Entwistle Kenneth M. , Walker John C.F. 
Published: January 2007

Abstract
The relation between growth stress and stress wave velocity has been investigated on standing trees of Eucalyptus nitens. Longitudinal growth stress and the stress wave velocity were measured at breast height on 155 trees. Large variation in both growth strain and acoustic velocity was observed. The initial investigation with 34 trees showed good correlation (R2=0.68). Measurements on all 155 trees revealed no reliable relationship (R2=0.05). The influence of internal stress on acoustic velocity has also been investigated on radiata pine boards loaded in bending and tension. It was observed that the resonance frequencies were influenced by the position of loaded supports in bending, but were not affected by the bending load. In boards under tensile stresses, there was no change in acoustic velocity measured by the pulse transit time. The two experimental series, one on standing trees with water-filled lumens and the other on air-dried boards, failed to reveal any dependence of the stress wave velocity on growth stress. No valid basis therefore exists for the use of stress wave velocity to determine growth stress levels in either standing trees or in seasoned wood.
Kiln-drying lumber quality of hybrid poplar clones
Authors: Kang Kyu-Young , Bradic Slobodan , Avramidis Stavros , Mansfield Shawn D. 
Published: January 2007

Abstract
Hybrid poplars are currently used in North America primarily for the production of pulp fibre and in the manufacture of engineered solid wood products. Recently, the deployment of poplars as a short-rotation fibre crop has been of interest to mitigate the increasing amount of plantation-grown short fibre resources (hardwoods) derived from the Southern Hemisphere, as well as in the context of global climate change, both as a means to rapidly sequester carbon and as a feedstock for potential bioenergy production. Knowledge on the utility of hybrid poplars in the value-added secondary wood-processing sector, however, is very limited. To improve this situation, the variation in kiln-drying quality of five hybrid poplar genotypes of similar age, harvested from a common site in British Columbia, Canada, was evaluated for three different kiln-drying schedules. The results clearly demonstrate that the drying schedule has a greater effect on grade recovery and the degree of deformation than the hybrid poplar genotype. Furthermore, it was shown that many of the deformations inherently associated with wood derived from fast-grown trees can be reduced or removed with drying, in particular with an aggressive drying schedule.
Heat and mass transfer in wood composite panels during hot pressing: Part 4. Experimental investigation and model validation
Authors: Dai Chunping , Yu Changming , Xu Changyan , He Guangbo 
Published: January 2007

Abstract
The effects of panel density and strand size on the temperature and gas pressure inside strand mats during hot pressing has been experimentally investigated. The results show good agreement with model predictions. Strand dimensions have a strong effect on the core temperature and gas pressure when the mat/panel density is relatively high. At lower density, the temperature and gas pressure are controlled only by the panel density. Comparison between the model predictions and experimental results also reveals the need for further characterisation of the basic mat properties, especially conductivity and permeability.
Dielectric relaxation of water adsorbed on wood and charcoal
Authors: Sugimoto Hiroyuki , Kanayama Kozo , Norimoto Misato 
Published: January 2007

AbstractThe dielectric relaxation due to motions of water molecules adsorbed on wood treated at various temperatures up to 550°C was investigated based on the relationships between activation enthalpy (ΔH) and entropy (ΔS) in relaxation. The relationships indicated two straight lines with different slopes, depending on the treatment temperature. Given the same ΔS, ΔHvalues for water molecules adsorbed on wood treated at temperatures below 400°C were greater than for those treated above 450°C. It was considered that before heat treatment, water molecules were adsorbed mainly on hydroxyl groups by strong hydrogen bonds and formed ice-like structures. On the other hand, hydroxyl groups were not detected in wood after heat treatments above 400°C. We assume that water molecules are condensed in nanometer-scale micropores that are formed during the carbonization of wood. The relationship between ΔHand ΔSfor the motion of water adsorbed on wood treated above 450°C was similar to the value extrapolated from that for bulk water at temperatures below 0°C. We suggest that water molecules are adsorbed on charcoal in a supercooled state.
Design of highly efficient cellulase mixtures for enzymatic hydrolysis of cellulose
Authors: Gusakov Alexander V. , Salanovich Tatyana N. , Antonov Alexey I. , Ustinov Boris B. , Okunev Oleg N. , Burlingame Richard , Emalfarb Mark , Baez Marco , Sinitsyn Arkady P. 
Published: January 2007

AbstractAn extremely highly active cellobiohydrolase (CBH IIb or Cel6B) was isolated from Chrysosporium lucknowense UV18‐25 culture filtrate. The CBH IIb demonstrated the highest ability for a deep degradation of crystalline cellulose amongst a few cellobiohydrolases tested, including C. lucknowense CBH Ia, Ib, IIa, and Trichoderma reesei CBH I and II. Using purified C. lucknowense enzymes (CBH Ia, Ib, and IIb; endoglucanases II and V; β‐glucosidase, xylanase II), artificial multienzyme mixtures were reconstituted, displaying an extremely high performance in a conversion of different cellulosic substrates (Avicel, cotton, pretreated Douglas fir wood) to glucose. These mixtures were much or notably more effective in hydrolysis of the cellulosic substrates than the crude multienzyme C. lucknowense preparation and other crude cellulase samples produced by T. reesei and Penicillium verruculosum. Highly active cellulases are a key factor in bioconversion of plant lignocellulosic biomass to ethanol as an alternative to fossil fuels. Biotechnol. Bioeng. 2007; 97: 1028–1038. © 2007 Wiley Periodicals, Inc.
Natural cellulose fibers from switchgrass with tensile properties similar to cotton and linen
Authors: Reddy Narendra , Yang Yiqi 
Published: January 2007

AbstractWe report the production and characteristics of natural cellulose fibers obtained from the leaves and stems of switchgrass. In this paper, the composition, structure and properties of fibers obtained from the leaves and stem of switchgrass have been studied in comparison to the common natural cellulose fibers, such as cotton, linen and kenaf. The leaves and stems of switchgrass have tensile properties intriguingly similar to that of linen and cotton, respectively. Fibers were obtained from the leaves and stems of switchgrass using a simple alkaline extraction and the structure and properties of the fibers were studied. Fibers obtained from switchgrass leaves have crystallinity of 51%, breaking tenacity of 5.5 g per denier (715 MPa) and breaking elongation of 2.2% whereas the corresponding values for fibers obtained from switchgrass stems are 46%, 2.7 g per denier and 6.8%, respectively. Switchgrass is a relatively easy to grow and high yield biomass crop that can be source to partially substitute the natural and synthetic fibers currently in use. We hope that this research will stimulate interests in using switchgrass as a novel fiber crop in addition to being promoted as a potential source for biofuels. Biotechnol. Bioeng. 2007; 97: 1021–1027. © 2007 Wiley Periodicals, Inc.
Dibutyl phthalate biodegradation by the white rot fungus, Polyporus brumalis
Authors: Lee Soo‐Min , Lee Jae‐Won , Koo Bon‐Wook , Kim Myung‐Kil , Choi Don‐Ha , Choi In‐Gyu 
Published: January 2007

AbstractIn this study, white rot fungus, Polyporus brumalis, was applied to degrade dibutyl phthalate (DBP), a major environmental pollutant. The degradation potential and resulting products were evaluated with HPLC and GC/MS. As DBP concentration increased to 250, 750, and 1,250 µM, the mycelial growth of P. brumalis was inhibited. However, growth was still observed in the 1,250 µM concentration. DBP was nearly eliminated from culture medium of P. brumalis within 12 days, with 50% of DBP adsorbed by the mycelium. Diethyl phthalate (DEP) and monobutyl phthalate (MBP) were detected as intermediate degradation products of DBP. In culture medium, the concentration of DEP was higher than that of MBP during the incubation period. After 12–15 days, the concentrations of both decreased rapidly in the culture medium. The primary final degradation product of DBP in culture medium was phthalic acid anhydride, as well as trace amounts of aromatic compounds, such as α‐hydroxyphenylacetic acid, benzyl alcohol, and O‐hydroxyphenylacetic acid. According to these results, the degradation of DBP in culture medium by the white rot fungus, P. brumalis, may be completed through two pathways—transesterification and de‐esterification—which successively combine into an intracellular degradation pathway. Biotechnol. Bioeng. 2007; 97: 1516–1522. © 2007 Wiley Periodicals, Inc.
Effect of Impurities on the Nucleation of ADP from Aqueous Solution
Authors: Nagalingam S. , Vasudevan S. , Ramasamy P. 
Published: January 2007

AbstractThe nucleation study has been made with the saturated solution of Ammonium dihydrogen orthophosphate over the temperature range 25–40 °C. In the absence of impurities, classical nucleation theory predicts rates reasonably well only at the expense of some adjustable parameters like surface energy term. This has been attributed to the difficulties associated with the application of equilibrium thermodynamics to a process of kinetic origin. The presence of soluble impurities reduces the solubility and hence decreases the induction period. In our present work the amount of soluble impurity added has influenced the induction period. Actvation energies and surface free energies were determined for ADP solution relative to the impurities.
Some Factors Influencing the Rate of Heterogeneous Nucleation of Strontium Sulphate
Authors: Söhnel O. 
Published: January 2007

AbstractThe effect of the agitation intensity on nucleation, agglomeration, ripening, and recrystallization of SrSO4 crystals prepared by batch precipitation of equimolar solutions of SrCl2 and Na2SO4 (0.01, 0.015, and 0.02 M) at 25 °C was investigated. The dependence of the SrSO4 crystals shape and number on the time of the suspension ageing was also studied.
Possible Inaccuracies Involved in the Crystal Population Balance Method and their Elimination
Authors: Nývlt J. , Žáček St. 
Published: January 2007

AbstractThe analysis of crystal size distribution using the method of population density balance is aggravated by two sources of possible errors: the uncertainty in calculating the population densities (numbers of crystals) from weight amounts of crystals and the necessity of extrapolating the population densities into the range of very small sizes in order to obtain the nuclei population density. Employment of cummulative weight distribution data overcomes both of these difficulties and serves results suitable for design purposes. The comparison of both methods is shown using experimental data on continuous potash alum precipitation.