bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anaerobes and their fermentation products in faeces of patients with familial adenomatous polyposis before and after subtotal colectomy and ileorectal anastomosis
Authors: MEIJER‐SEVERS G. J. , CATS A. , VERSCHUEREN R. C. J. , SANTEN E. VAN. , KLEIBEUKER J. H. 
Published: March 2008

Abstract. In view of the importance of short‐chain fatty acids (SCFA) for the colonic epithelial function and their possible relation with the reported spontaneous regression of rectal polyps after subtotal colectomy with ileorectal anastomosis, we compared the SCFA concentrations in faeces of five familial adenomatous polyposis (FAP) patients before, and in 10 FAP patients after operation to each other and to those of 10 healthy controls. Anaerobe cultural counts and concentrations of organic acids were also investigated in the same faecal samples from FAP patients and controls.The preoperative cultural counts were not significantly different from those of the controls. After colectomy, the Bacteroides (P<0.002; P<0.02), and bifidobacteria counts (P<0.02; P<0.005) were decreased compared to controls and untreated FAP patients. The ratio of acetic acid to total SCFA significantly increased, which coincided with a proportional decrease of the other SCFA.The frequently observed regression of rectal polyps after colectomy cannot be explained from these results. One would rather expect a possible stimulation of polyp growth and dedifferentiation of colonic epithelial cells.
Increase in plasma 3,4‐dihydroxyphenylalanine (DOPA) appearance rate after inhibition of DOPA decarboxylase in humans
Authors: ELDRUP E. , HETLAND M. LUND , CHRISTENSEN N. JUEL 
Published: March 2008

Abstract. Concentrations of DOPA in plasma are relatively high as compared to norepinephrine. The significance of plasma DOPA has not been elucidated. One would expect that substantial amounts of DOPA are derived from sympathetic nerves. There appears, however, neither to be a depot of DOPA in nerves nor is there a close correlation between plasma DOPA and sympathetic activity. The aim of the present study was to obtain further information about plasma DOPA by studying DOPA kinetics in healthy humans both with and without inhibition of DOPA decarboxylase by benserazide. Plasma DOPA and other catecholamines were measured by reverse‐phase HPLC with electrochemical detection and DOPA clearance and appearance rate were studied using infusion of 3H‐DOPA.The plasma clearance of DOPA was 1·02 1 min‐1. Approximately 20% of this value could be explained by DOPA being decarboxylated in the kidneys and excreted as dopamine. The DOPA appearance rate was 1·13 μg min‐1 and the extremities accounted for approximately 1/5 of this value. After inhibition of DOPA decarboxylase by benserazide the DOPA appearance rate increased 7‐fold, whereas the DOPA clearance only decreased slightly and insignificantly. These findings are probably explained by two factors: (1) There is normally a large production of DOPA in some tissues from which DOPA spillover into plasma only occurs to a minor extent and tracer DOPA only mixes with this compartment to a small degree; (2) These compartments are permeable to benserazide, which blocks the decarboxylation of DOPA, which then leaves the tissues and spillover to plasma. Our results are compatible with the view that substantial amounts of DOPA are normally decarboxylated in sympathetic nerves, and spillover to plasma only if DOPA cannot be decarboxylated to dopamine. We conclude that plasma DOPA concentration neither reflects sympathetic nerve activity nor tyrosine hydroxylase activity. Provided plasma DOPA to a major extent is derived from sympathetic nerves it probably reflects the minimal fraction of DOPA synthesized but not decarboxylated to dopamine in nerves.
Renal toxicity mediated by glucose degradation products in a rat model of advanced renal failure
Authors: Müller‐Krebs S. , Kihm L. P. , Zeier B. , Gross M. L. , Deppisch R. , Wieslander A. , Henle T. , Penndorf I. , Oh J. , Reiser J. , Nawroth P. P. , Zeier M. , Schwenger V. 
Published: March 2008

ABSTRACTBackground  In peritoneal dialysis (PD) residual renal function contributes to improved patient survival and quality of life. Glucose degradation products (GDP) generated by heat sterilization of PD fluids do not only impair the peritoneal membrane, but also appear in the systemic circulation with the potential for organ toxicity. Here we show that in a rat model of advanced renal failure, GDP affect the structure and function of the remnant kidney.Materials and methods  Sprague‐Dawley rats were randomly assigned to a two stage subtotal nephrectomy (SNX) or sham operation and were left untreated for 3 weeks. The SNX + GDP group continuously received chemically defined GDP intravenously for 4 weeks; the SNX and the sham‐operated rats remained without GDP. The complete follow‐up for all groups was 7 weeks postoperatively.We analysed renal damage using urinary albumin excretion as well as a semiquantitative score for glomerulosclerosis and tubulointerstitial damage, as well as for immunohistochemical analyses.Results  The SNX + GDP rats developed significantly more albuminuria and showed a significantly higher score of glomerulosclerosis index (GSI) and tubulointerstitial damage index (TII) as compared to SNX or control rats. In the SNX + GDP group the expression of carboxymethyllysine and methylglyoxal was significantly higher in the tubulointerstitium and the glomeruli compared to the SNX rats. Caspase 3 staining and TUNEL assay were more pronounced in the tubulointerstitium and the glomeruli of the SNX + GDP group. In SNX + GDP animals, the expression of the slit diaphragm protein nephrin, was significantly lower compared to SNX or control animals.Conclusion  In summary, our data suggests that GDP can significantly advance chronic kidney disease and argues that PD solutions containing high GDP might deteriorate residual renal function in PD.
Surface sediment diatom assemblages and epilimnetic total phosphorus in large, shallow lakes of the Yangtze floodplain: their relationships and implications for assessing long‐term eutrophication
Authors: YANG XIANGDONG , ANDERSON N. JOHN , DONG XUHUI , SHEN JI 
Published: March 2008

Summary1. The Yangtze floodplain (SE China) is characterized by a number of large shallow lakes, many of which have undergone eutrophication due to the intensification of agriculture and urban growth over recent decades. As monitoring data are limited and in order to determine lake baseline nutrient concentrations, 49 lakes were sampled, covering a total phosphorus (TP) gradient (c. 30–550 μg L−1) to develop a diatom‐based inference model.2. There are three dominant diatom assemblages in these shallow lakes with a marked change in assemblage structure near the boundary between eutrophic and hypereutrophic nutrient levels (as indicated by their TP value). Canonical correspondence analysis indicated that TP was the most important and significant variable in explaining the diatom distributions, independently accounting for 9.5% variance of diatoms.3. Forty‐three lakes were used to generate a transfer function using weighted averaging (WA) with inverse deshrinking. This model had low predictive error (root mean squared error of prediction; RMSEPjack = 0.12) and a high coefficient of prediction (R2jack = 0.82), comparable with regional TP models elsewhere. The good performance of this TP model may reflect the low abundance of benthic diatom species which are commonly regarded as the main error source in European shallow lake WA models.4. The WA model was used to reconstruct the past‐TP concentrations for Taibai Lake, a shallow hypereutrophic lake in Hubei province. The results showed that TP concentration varied slightly (43–62 μg L−1) prior to the 1920s, indicating an eutrophic state since the 1800s. A period of sustained eutrophication occurred after 1950, because of the development of agriculture, reflecting by maximum values of Aulacoseira alpigena and increased abundance of Cyclotella meneghiniana, C. atomus and Cyclostephanos dubius. The steep increase in nutrient concentration after 1970 was related to the overuse of chemical fertilizer and fish farming in the catchment.5. The shift in fossil diatoms from epiphytic to planktonic forms in the lake sediment core during 1950–70 provides useful information on the transformation from macrophyte‐dominated to alga‐dominated states. It is plausible that the TP concentration of 80–110 μg L−1 observed in this study is the critical range for switching between the two stable states in the lake.6. The regional diatom‐TP model developed in this study allows, therefore, the possibility of reconstructing historical background nutrient concentrations in lakes. It will provide an indication of the onset and development of eutrophication at any site. This is particularly important for the many lakes in the Yangtze floodplain where information about historical changes in water quality is lacking.
Fatty Acid and Isoprenoid Quinone Composition in the classification of Bacteroides melaninogenicus and Related Taxa
Authors: SHAH H. N. , COLLINS M. D. 
Published: March 2008

The fatty acid and isoprenoid quinone composition of 37 Bacteroides strains was examined. In a single strain of Bacteroides melaninogenicus subsp. levii neither menaquinones nor ubiquinones was detected. Menaquinones were the only isoprenoid quinones found in the remaining 36 Bacteroides strains examined. Unsaturated menaquinones with six isoprene units were the main components isolated from B. ochraceus. The menaquinone components of B. asaccharolyticus strains enable them to be divided into two subgroups containing menaquinones with nine and ten isoprene units respectively. Bacteroides vulgatus strains contained menaquinones with ten isoprene units as the major component, whereas B. fragilis, B. thetaiotaomicron and B. melaninogenicus subsp. melaninogenicus were characterized by comparable amounts of menaquinones with 10 and 11 isoprene units. Unsaturated menaquinones with 11 isoprene units were found in B. melaninogenicus subsp. intermedius and with 11 and 12 isoprene units in rumen strains of B. ruminicola subsp. brevis and B. ruminicola subsp. ruminicola. By contrast, oral strains of B. ruminicola subsp. brevis were characterized by major amounts of menaquinones with 12 and 13 isoprene units. Strains at present designated B. oralis, however, were heterogeneous with respect to menaquinone composition.The non‐hydroxylated fatty acids of all the Bacteroides strains examined consisted predominantly of straight‐chain, anteiso‐ and iso‐methyl branched‐chain acids. Monounsaturated fatty acids were found in only small amounts. The major fatty acid in B. ochraceus and B. asaccharolyticus strains was 13‐methyltetradecanoic acid (iso C15) whereas 12‐methyl‐tetradecanoic acid (anteiso C15) predominated in B. melaninogenicus subsp. melaninogenicus. B. melaninogenicus subsp. intermedius. B. melaninogenicus subsp. levii, B. oralis and oral isolates of B. ruminicola subsp, brevis. The rumen strains of B. ruminicola subsp. brevis and B. ruminicola subsp. ruminicola were characterized by major amounts of anteiso C15 and pentadecanoic (C15:0) fatty acids.The accumulated lipid data correlate well with the major trends in Bacteroides taxonomy and appear to be of value in the classification of this group.
ORIGINAL ARTICLE: Vascular plant species richness in relation to habitat diversity and island area in the Finnish Archipelago
Authors: Hannus Jens‐Johan , Von Numers Mikael 
Published: March 2008

AbstractAim  The aim of this study is to explore the interrelationships between island area, species number and habitat diversity in two archipelago areas.Location  The study areas, Brunskär and Getskär, are located in an archipelago in south‐western Finland.Methods  The study areas, 82 islands in Brunskär and 78 in Getskär, were classified into nine habitat types based on land cover. In the Brunskär area, the flora (351 species) was surveyed separately for each individual habitat on the islands. In the Getskär area, the flora (302 species) was surveyed on a whole‐island basis. We used standard techniques to analyse the species–area relationship on a whole‐island and a habitat level. We also tested our data for the small island effect (SIE) using breakpoint and path analysis models.Results  Species richness was significantly associated with both island area and habitat diversity. Vegetated area in particular, defined as island area with the rock habitat subtracted, proved to be a strong predictor of species richness. Species number had a greater association with island area multiplied by the number of habitats than with island area or habitat number separately. The tests for a SIE in the species–area relationship showed the existence of a SIE in one of the island groups. No SIE could be detected for the species–vegetated area relationship in either of the island groups. The strength of the species–area relationship differed considerably between the habitats.Main conclusions  The general principles of island biogeography apply well to the 160 islands in this study. Vascular plant diversity for small islands is strongly influenced by physiographic factors. For the small islands with thin and varying soil cover, vegetated area was the most powerful predictor of species richness. The species–area curves of various habitats showed large variations, suggesting that the measurement of habitat areas and establishment of habitat‐based species lists are needed to better understand species richness on islands. We found some evidence of a SIE, but it is debatable whether this is a ‘true’ SIE or a soil cover/habitat characteristics feature.
A survey of modern pollen and vegetation along a south–north transect in Mongolia
Authors: Ma Yuzhen , Liu Kam‐biu , Feng Zhaodong , Sang Yanli , Wang Wei , Sun Aizhi 
Published: March 2008

AbstractAim  This modern pollen‐rain study documents the spatial and quantitative relationships between modern pollen and vegetation in Mongolia, and explores the potential for using this relationship in palaeoclimatic reconstructions.Location  East‐central Mongolia.Methods  We collected 104 pollen surface samples along a south–north transect across five vegetation zones in Mongolia. Discriminant analysis was used to classify the modern pollen spectra into five pollen assemblages corresponding to the five vegetation zones. Hierarchical cluster analysis was used to divide the main pollen taxa into two major groups and seven subgroups representing the dry and moist vegetation types and the main vegetation communities within them.Results  Each vegetation zone along the transect can be characterized by a distinctive modern pollen assemblage as follows: (1) desert zone: Chenopodiaceae–Zygophyllaceae–Nitraria–Poaceae pollen assemblage; (2) desert‐steppe zone: Poaceae–Chenopodiaceae pollen assemblage; (3) steppe zone: Artemisia–Aster‐type–Poaceae–Pinus Haploxylon‐type pollen assemblage; (4) forest‐steppe zone: Pinus Haploxylon‐type–Picea–Artemisia–Betula, montane forb/shrub and pteridophyte pollen assemblage; and (5) mountain taiga zone: Pinus Haploxylon‐type–Picea–Poaceae–Cyperaceae, montane forb/shrub and Pteridophyte pollen assemblage.Main conclusions  Based on the ratio between the major pollen taxon groups and subgroups, we propose two pollen–climate indices that represent the precipitation and temperature conditions in the study region. When plotted along our south–north transect, the moisture indices (M) and temperature indices (T) mimic the regional gradients of precipitation and temperature across Mongolia very closely. These pollen–climate indices can be used for palaeoclimatic reconstruction based on fossil pollen data.
Mycothiol regulates and is regulated by a thiol‐specific antisigma factor RsrA and σR in Streptomyces coelicolor
Authors: Park Joo‐Hong , Roe Jung‐Hye 
Published: March 2008

SummaryMycothiol (MSH) is a small thiol molecule with a cysteine‐ligated disaccharide structure found in actinomycetes that include streptomycetes and mycobacteria. In Streptomyces coelicolor, a model organism for antibiotic production and differentiation, the amount of MSH is under the control of a sigma factor σR, which is regulated by an antisigma factor RsrA with a thiol‐disulphide redox switch. We found that the first gene (mshA) in the biosynthetic pathway for MSH and the gene for amidase (mca) that participates in detoxifying mycothiol‐reactive drugs are under direct control of σR. The σR target genes are induced not only by a thiol oxidant diamide, but also by alkylating agents that cause a rapid decrease in MSH. Expression of the σR regulon was also elevated in MSH‐deficient mutants, suggesting that a decrease in the level of MSH is a natural intracellular trigger for σR activation. We found that MSH was capable of reducing RsrA to bind σR, whereas glutathione was not. These results support a proposal that the RsrA‐σR system senses the intracellular level of reduced MSH, and that MSH serves as a natural modulator of the transcription system for its own replenishment in addition to being a redox buffer and drug detoxifier.
Complement Component C1q and Anti‐C1q Antibodies in Theory and in Clinical Practice
Authors: Potlukova E. , Kralikova P. 
Published: March 2008

AbstractThe complement system is a major part of the innate immunity. The first component of the classical pathway of complement activation, C1q, plays a crucial role in the clearance of immune complexes and apoptotic bodies from the organism. Autoantibodies against C1q (anti‐C1q) have been found in a number of autoimmune and infectious diseases. They have been best described in patients with systemic lupus erythematosus, where they are thought to play a pathogenic role in lupus nephritis (LN). Their high negative predictive value for the occurrence of active proliferative LN, as well as their possible ability to indicate a renal flare as soon as 6 months in advance, have rendered anti‐C1q antibodies a novel non‐invasive tool in the detection of active LN.
A role for protein kinase CK2 in plant development: evidence obtained using a dominant‐negative mutant
Authors: Moreno‐Romero Jordi , Carme Espunya M. , Platara Maria , Ariño Joaquin , Carmen Martínez M. 
Published: March 2008

SummaryProtein kinase CK2 is an evolutionary conserved Ser/Thr phosphotransferase composed of two distinct subunits, α (catalytic) and β (regulatory), that combine to form a tetrameric complex. Plant genomes contain multiple genes for each subunit, the expression of which gives rise to different active holoenzymes. In order to study the effects of loss of function of CK2 on plant development, we have undertaken a dominant‐negative mutant approach. We generated an inactive catalytic subunit by site‐directed mutagenesis of an essential lysine residue. The mutated open reading frame was cloned downstream of an inducible promoter, and stably transformed Arabidopsis thaliana plants and tobacco BY2 cells were isolated. Continuous expression of the CK2 kinase‐inactive subunit did not prevent seed germination, but seedlings exhibited a strong phenotype, affecting chloroplast development, cotyledon expansion, and root and shoot growth. Prolonged induction of the transgene was lethal. Moreover, dark‐germinated seedlings exhibited an apparent de‐etiolated phenotype that was not caused by disruption of the light‐signalling pathways. Short‐term induction of the CK2 kinase‐inactive subunit allowed plant survival, but root growth and lateral root formation were significantly affected. The expression pattern of CYCB1;1::GFP in the root meristems of mutant plants demonstrated an important decrease of mitotic activity, and expression of the CK2 kinase‐inactive subunit in stably transformed BY2 cells provoked perturbation of the G1/S and G2 phases of the cell cycle. Our results are consistent with a model in which CK2 plays a key role in cell division and cell expansion, with compelling effects on Arabidopsis development.
Two nearly identical terpene synthases catalyze the formation of nerolidol and linalool in snapdragon flowers
Authors: Nagegowda Dinesh A. , Gutensohn Michael , Wilkerson Curtis G. , Dudareva Natalia 
Published: March 2008

SummaryTerpenoids emitted from snapdragon flowers include three monoterpenes derived from geranyl diphosphate (GPP), myrcene, (E)‐β‐ocimene and linalool, and a sesquiterpene, nerolidol, derived from farnesyl diphosphate (FPP). Using a functional genomics approach, we have isolated and biochemically characterized two nearly identical nerolidol/linalool synthases, AmNES/LIS‐1 and AmNES/LIS‐2, two enzymes responsible for the terpenoid profile of snapdragon scent remaining to be characterized. The AmNES/LIS‐2 protein has an additional 30 amino acids in the N‐terminus, and shares 95% amino acid sequence identity with AmNES/LIS‐1, with only 23 amino acid substitutions distributed across the homologous regions of the proteins. Although these two terpene synthases have very similar catalytic properties, and synthesize linalool and nerolidol as specific products from GPP and FPP, respectively, they are compartmentally segregated. GFP localization studies and analysis of enzyme activities in purified leucoplasts, together with our previous feeding experiments, revealed that AmNES/LIS‐1 is localized in cytosol, and is responsible for nerolidol biosynthesis, whereas AmNES/LIS‐2 is located in plastids, and accounts for linalool formation. Our results show that subcellular localization of bifunctional enzymes, in addition to the availability of substrate, controls the type of product formed. By directing nearly identical bifunctional enzymes to more than one cellular compartment, plants extend the range of available substrates for enzyme utilization, thus increasing the diversity of the metabolites produced.
Influence of population structure on estimates of direct and maternal parameters
Authors: Heydarpour M. , Schaeffer L.R. , Yazdi M.H. 
Published: March 2008

SummaryThe estimation of (co)variance components for multiple traits with maternal genetic effects was found to be influenced by population structure. Two traits in a closed breeding herd with random mating were simulated over nine generations. Population structures were simulated on the basis of different proportions of dams not having performance records (0, 0.1, 0.5, 0.8 and 0.9): three genetic correlations (−0.5, 0.0 and +0.5) between direct and maternal effects and three genetic correlations (0, 0.3 and 0.8) between two traits. Three ratios of direct to maternal genetic variances, (1:3, 1:1, 3:1), were also considered. Variance components were estimated by restricted maximum likelihood. The proportion of dams without records had an effect on the SE of direct–maternal covariance estimates when the proportion was 0.8 or 0.9 and the true correlation between direct and maternal effects was negative. The ratio of direct to maternal genetic variances influenced the SE of the (co)variance estimates more than the proportion of dams with missing records. The correlation between two traits did not have an effect on the SE of the estimates. The proportion of dams without records and the correlation between direct and maternal effects had the strongest effects on bias of estimates. The largest biases were obtained when the proportion of dams without records was high, the correlation between direct and maternal effects was positive, and the direct variance was greater than the maternal variance, as would be the situation for most growth traits in livestock. Total bias in all parameter estimates for two traits was large in the same situations. Poor population structure can affect both bias and SE of estimates of the direct–maternal genetic correlation, and can explain some of the large negative estimates often obtained.