bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phosphatidylinositol‐4,5‐bisphosphate influences Nt‐Rac5‐mediated cell expansion in pollen tubes of Nicotiana tabacum
Authors: Ischebeck Till , Stenzel Irene , Hempel Franziska , Jin Xu , Mosblech Alina , Heilmann Ingo 
Published: November 2010

SummaryThe regulation of pollen tube growth by the phospholipid phosphatidylinositol‐4,5‐bisphosphate (PtdIns(4,5)P2) is not well understood. The Arabidopsis genome encodes two type A phosphatidylinositol‐4‐phosphate (PI4P) 5‐kinases, PIP5K10 and PIP5K11, which are exclusively expressed in pollen and produce PtdIns(4,5)P2in vitro. Fluorescence‐tagged PIP5K10 and PIP5K11 localized to lateral subapical plasma membrane microdomains in tobacco pollen tubes in a pattern closely resembling the distribution of PtdIns(4,5)P2, with the exception of notably weaker association at the extreme apex. Overexpression of PIP5K10 or PIP5K11 in tobacco pollen tubes resulted in severe tip swelling and altered actin fine structure similar to that reported for overexpression of tobacco Nt‐Rac5, a monomeric GTPase known to regulate the actin cytoskeleton. Increased sensitivity of Arabidopsis pip5k10 pip5k11 double mutant pollen tubes to Latrunculin B (LatB) further supports a role for type A PI4P 5‐kinases in controlling the actin cytoskeleton. Despite the disruption of both its type A PI4P 5‐kinases, the pip5k10 pip5k11 double mutant was fertile, indicating that one of the remaining type B PI4P 5‐kinase isoforms might be functionally redundant with PIP5K10 and PIP5K11. Antagonistic effects of PIP5K11 and the Nt‐Rac5‐specific guanine nucleotide dissociation inhibitor, Nt‐RhoGDI2, on tip swelling observed in coexpression‐titration experiments indicate a link between PtdIns(4,5)P2 and Rac‐signaling in pollen tubes. The data suggest that type A PI4P 5‐kinases influence the actin cytoskeleton in pollen tubes in part by counteracting Nt‐RhoGDI2, possibly contributing to the control of the pool of plasma membrane‐associated Nt‐Rac5.
Priming for enhanced defence responses by specific inhibition of the Arabidopsis response to coronatine
Authors: Tsai Chia‐Hong , Singh Prashant , Chen Ching‐Wei , Thomas Jerome , Weber Johann , Mauch‐Mani Brigitte , Zimmerli Laurent 
Published: November 2010

SummaryThe priming agent β‐aminobutyric acid (BABA) is known to enhance Arabidopsis resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000 by potentiating salicylic acid (SA) defence signalling, notably PR1 expression. The molecular mechanisms underlying this phenomenon remain unknown. A genome‐wide microarray analysis of BABA priming during Pst DC3000 infection revealed direct and primed up‐regulation of genes that are responsive to SA, the SA analogue benzothiadiazole and pathogens. In addition, BABA was found to inhibit the Arabidopsis response to the bacterial effector coronatine (COR). COR is known to promote bacterial virulence by inducing the jasmonic acid (JA) response to antagonize SA signalling activation. BABA specifically repressed the JA response induced by COR without affecting other plant JA responses. This repression was largely SA‐independent, suggesting that it is not caused by negative cross‐talk between SA and JA signalling cascades. Treatment with relatively high concentrations of purified COR counteracted BABA inhibition. Under these conditions, BABA failed to protect Arabidopsis against Pst DC3000. BABA did not induce priming and resistance in plants inoculated with a COR‐deficient strain of Pst DC3000 or in the COR‐insensitive mutant coi1‐16. In addition, BABA blocked the COR‐dependent re‐opening of stomata during Pst DC3000 infection. Our data suggest that BABA primes for enhanced resistance to Pst DC3000 by interfering with the bacterial suppression of Arabidopsis SA‐dependent defences. This study also suggests the existence of a signalling node that distinguishes COR from other JA responses.
The COP9 signalosome controls jasmonic acid synthesis and plant responses to herbivory and pathogens
Authors: Hind Sarah R. , Pulliam Sarah E. , Veronese Paola , Shantharaj Deepak , Nazir Azka , Jacobs Nekaiya S. , Stratmann Johannes W. 
Published: November 2010

SummaryThe COP9 signalosome (CSN) is a multi‐protein complex that regulates the activities of cullin‐RING E3 ubiquitin ligases (CRLs). CRLs ubiquitinate proteins in order to target them for proteasomal degradation. The CSN is required for proper plant development. Here we show that the CSN also has a profound effect on plant defense responses. Silencing of genes for CSN subunits in tomato plants resulted in a mild morphological phenotype and reduced expression of wound‐responsive genes in response to mechanical wounding, attack by Manduca sexta larvae, and Prosystemin over‐expression. In contrast, expression of pathogenesis‐related genes was increased in a stimulus‐independent manner in these plants. The reduced wound response in CSN‐silenced plants corresponded with reduced synthesis of jasmonic acid (JA), but levels of salicylic acid (SA) were unaltered. As a consequence, these plants exhibited reduced resistance against herbivorous M. sexta larvae and the necrotrophic fungal pathogen Botrytis cinerea. In contrast, susceptibility to tobacco mosaic virus (TMV) was not altered in CSN‐silenced plants. These data demonstrate that the CSN orchestrates not only plant development but also JA‐dependent plant defense responses.
The RecQ helicase AtRECQ4A is required to remove inter‐chromosomal telomeric connections that arise during meiotic recombination in Arabidopsis
Authors: Higgins James D. , Ferdous Maheen , Osman Kim , Franklin F. Christopher H. 
Published: November 2010

SummaryRecQ helicases are a conserved group of proteins with a role in the maintenance of genome integrity. In Saccharomyces cerevisiae (budding yeast), meiotic recombination is increased in the absence of the RecQ helicase Sgs1. Here we investigated the potential meiotic role of the Sgs1 homologue AtRECQ4A and the closely related AtRECQ4B. Both proteins have been shown to function during recombination in somatic cells, but so far their meiotic role has not been investigated. Both AtRECQ4A and AtRECQ4B were expressed in reproductive tissues. Although immunolocalization studies showed that AtRECQ4A associates with recombination intermediates, we found no evidence that its loss or that of AtRECQ4B had a significant effect on meiotic cross‐overs, suggesting functional redundancy with other RECQ family members. Nevertheless, pollen viability decreased in Atrecq4A, resulting in a reduction in fertility, although this was not the case in Atrecq4B. Cytological analysis revealed chromatin bridges between the telomeres of non‐homologous chromosomes in Atrecq4A at metaphase I, in some instances accompanied by chromosome fragmentation at anaphase I. The bridges required telomeric repeats and were dependent on meiotic recombination. Immunolocalization confirmed the association of AtRECQ4A with the telomeres during prophase I, which we propose enables dissolution of recombination‐dependent telomeric associations. Thus, this study has identified a hitherto unknown role for a member of the RECQ helicase family during meiosis that contributes to the maintenance of chromosome integrity. As telomere structure is generally conserved, it seems likely that these associations may arise during meiosis in other species, where they must also be removed.
Ring chromosome 22 and neurofibromatosis type II: proof of two‐hit model for the loss of the NF2 gene in the development of meningioma
Authors: Zirn B , Arning L , Bartels I , Shoukier M , Hoffjan S , Neubauer B , Hahn A 
Published: November 2010

Zirn B, Arning L, Bartels I, Shoukier M, Hoffjan S, Neubauer B, Hahn A. Ring chromosome 22 and neurofibromatosis type II: proof of two‐hit model for the loss of the NF2 gene in the development of meningioma.Carriers of a ring chromosome 22 are mentally retarded and show variable facial dysmorphism. They may also present with features of neurofibromatosis type II (NF2) such as vestibular schwannomas and multiple meningiomas. In these cases, tumourigenesis has been suspected to be caused by the loss of both alleles of the NF2 gene, a tumour suppressor localized in 22q12.2. Here, we describe an 18‐year‐old patient with constitutional ring chromosome 22 and mental retardation who developed rapid‐onset spastic paraparesis at the age of 15 years. The causative spinal meningioma at the level of T3, which compressed the spinal cord, was surgically removed, and the patient regained ambulation. Array comparative genomic hybridization (array CGH) and multiplex ligation‐dependent probe amplification (MLPA) analyses in blood revealed a terminal deletion in 22q13.32, not comprising the NF2 gene. In tumour tissue, loss of the whole ring chromosome 22 including one NF2 gene due to mitotic instability constituted the likely first hit, while a point mutation in the other allele of the NF2 gene (c.784C>T, p.R262X) was shown as second hit. We review all cases from the literature and suggest clinical guidelines for surveillance of patients with ring chromosome 22.
Participants’ experiences of intensifying insulin therapy during the Treating to Target in Type 2 Diabetes (4‐T) trial: qualitative interview study
Authors: Jenkins N. , Hallowell N. , Farmer A. J. , Holman R. R. , Lawton J. 
Published: November 2010

Diabet. Med. 28, 543–548 (2011)AbstractAim  To explore participants’ experiences of intensifying insulin therapy during the Treating to Target in Type 2 Diabetes (4‐T) trial.Methods  In‐depth interviews were conducted with 41 trial participants who had had their insulin therapy intensified during this trial. Data were analysed using an inductive, thematic approach.Results  The vast majority of participants were receptive towards intensifying treatment. Whilst some were happy simply to follow health professionals’ recommendations, others saw taking two types of insulin as a more effective way of controlling their diabetes. Post‐intensification, participants sought to remember to take their additional injections by developing injection‐related strategies and daily routines. The need to inject insulin whilst in public often arose more frequently following intensification and was a consistent source of anxiety. Those who were worried about injecting in public sought to avoid having to do so; for example, by injecting in toilets or by advancing or delaying the timing of their injections.Conclusions  It was not increasing the number of daily injections per se which was problematic for the participants who had agreed to have their insulin therapies intensified, but the increased likelihood of having to inject insulin in public. Addressing concerns about injecting in public places may help promote adherence to intensified insulin regimens.
Implementing Carbon‐Footprint‐Based Calculation Tools in Municipal Greenhouse Gas Inventories
Authors: Larsen Hogne N. , Hertwich Edgar G. 
Published: November 2010

SummaryPolicy makers and practitioners working on local climate action continuously strive for improved greenhouse gas (GHG) inventories to support their mitigation strategies. The provision of such inventories, with the sufficient detail and quality needed, has proven to be challenging. This article describes the application of a carbon‐footprint–based (CF‐based) calculation tool to Norwegian municipalities. The aim is to improve the local GHG inventory, with a particular focus on the emissions resulting from the provision of services by local governments. Through selective CF analysis, we aim to illustrate the knowledge gained from implementing these tools in local climate action plans and to further contrast CF‐based calculations with more traditional production‐based accounting. Municipalities report they have revised their understanding of the most important GHG mitigation strategies after implementing this tool.
Differential Impacts of Solar UV Radiation on Photosynthetic Carbon Fixation from the Coastal to Offshore Surface Waters in the South China Sea
Authors: Li Gang , Gao Kunshan , Gao Guang 
Published: November 2010

AbstractWe carried out experiments during an expedition (14 August to 14 September, 2007) that covered up to 250 000 km2 to investigate the effects of solar UV radiation (UVR, 280–400 nm) on the photosynthetic carbon fixation of tropical phytoplankton assemblages in surface seawater of the South China Sea. From coastal to pelagic surface seawaters, UV‐B (280–315 nm) caused similar inhibition, while UV‐A (315–400 nm) induced photosynthetic inhibition increased from coastal to offshore waters. UV‐B resulted in an inhibition by up to 27% and UV‐A by up to 29%. Under reduced levels of solar radiation with heavy overcast, UV‐A resulted in enhanced photosynthetic carbon fixation by up to 25% in coastal waters where microplankton was abundant. However, such a positive impact was not observed in the offshore waters where piconanoplankton was more abundant. The daily integrated inhibition of UV‐A reached 4.3% and 13.2%, and that of UV‐B reached 16.5% and 13.5%, in the coastal and offshore waters, respectively.
Investigation of Photocatalytic Effect of SnO2 Nanoparticles Synthesized by Hydrothermal Method on the Decolorization of Two Organic Dyes
Authors: Esen Bekir , Yumak Tuğrul , Sınağ Ali , Yıldız Tuğba 
Published: November 2010

AbstractTin oxide nanoparticles about 4 nm in size were successfully synthesized using hydrothermal method. The photocatalytic activity of the particles was determined by the decolorization of malachite green (MG) and titanium yellow (TY) under UV light. 12 ppm of MG and TY were used for the solution with an initial volume of 100 mL. The amounts of catalysts were 10, 30 and 50 mg. The effect of the catalyst loading on the reaction kinetic parameters and the decolorization rate constants (k) were determined. In order to reveal the photocatalytic efficiency of the nano particles, further experiments were conducted with bulk SnO2. The oxygen species registered no observable effect on the reaction mechanism as nitrogen bubbling leads to no change in decolorization rates. Results showed that the synthesized nano tin oxide particles represent excellent photocatalytic activity for the decolorization of 12 ppm MG under UV light with 150 min of irradiation time. The energies of the highest occupied molecular orbital (HOMO) EHOMO of the dyes were also calculated by using the quantum chemical software in order to discuss the differences for the decolorization of two dyes. Electrical energy efficiency values for the decolorization of two dyes were also calculated.
Diversity of the
fsr-gelE
Region of the
Enterococcus faecalis
Genome but Conservation in Strains with Partial Deletions of the
fsr
Operon
Authors: Galloway-Peña Jessica R. , Bourgogne Agathe , Qin Xiang , Murray Barbara E. 
Published: November 2010

ABSTRACT

Most
Enterococcus faecalis
isolates carry
gelE
, but many are gelatinase nonproducers due to the lack of
fsrC
(EF_1820) to EF_1841 (
f
srC
-EF_1841; 23.9 kb in strain V583), including most of the locus encoding Fsr, which activates
gelE
expression. Analysis of 22 accessible
E. faecalis
genomes revealed the identity of the 53-amino-acid propeptide of
fsrD
across multiple MLSTs (multilocus sequence types), although 12 distinctly different variations were found in the EF_1814-to-EF_1902 region. Diversity was seen in
fsrABC
, in the region EF_1814 to EF_1902, and in a 700-kb region surrounding
fsrC
-EF_1841. However, analysis of five sequenced strains carrying the
fsrC
-EF_1841 deletion and the putative integrative conjugative element efaB5 showed almost identical single nucleotide polymorphisms (SNPs) in
gelE
and an identical junction sequence, despite their unrelated MLSTs, in contrast to those shown by strains without the deletion. Further analysis confirmed the conserved
gelE
SNPs in 6 additional strains (11 in total) with the deletion. While we were unable to detect evidence of spontaneous deletion using OG1RF and 8 other strains, we were able to engineer a deletion of the 37-kb
fsrC
-EF_1841 region of OG1RF without deleterious effects, and the 37-kb mutant showed changes in biofilm and chaining similar to those shown by
fsr
-
gelE
mutants. In conclusion, we describe the identity of
fsrD
despite high plasticity within the
fsrC
-EF_1841 region and the surrounding sequence. However, strains lacking the
fsrC
-EF_1841 region show a distinct conservation of the sequence surrounding this deletion and in
gelE
, suggesting that the deletion may result from horizontal transfer and recombination.
Influence of Plant Polymers on the Distribution and Cultivation of Bacteria in the Phylum
Acidobacteria
Authors: Eichorst Stephanie A. , Kuske Cheryl R. , Schmidt Thomas M. 
Published: November 2010

ABSTRACT

Members of the phylum
Acidobacteria
are among the most abundant bacteria in soil. Although they have been characterized as versatile heterotrophs, it is unclear if the types and availability of organic resources influence their distribution in soil. The potential for organic resources to select for different acidobacteria was assessed using molecular and cultivation-based approaches with agricultural and managed grassland soils in Michigan. The distribution of acidobacteria varied with the carbon content of soil: the proportion of subdivision 4 sequences was highest in agricultural soils (ca. 41%) that contained less carbon than grassland soils, where the proportions of subdivision 1, 3, 4, and 6 sequences were similar. Either readily oxidizable carbon or plant polymers were used as the sole carbon and energy source to isolate heterotrophic bacteria from these soils. Plant polymers increased the diversity of acidobacteria cultivated but decreased the total number of heterotrophs recovered compared to readily oxidizable carbon. Two phylogenetically novel
Acidobacteria
strains isolated on the plant polymer medium were characterized. Strains KBS 83 (subdivision 1) and KBS 96 (subdivision 3) are moderate acidophiles with pH optima of 5.0 and 6.0, respectively. Both strains grew slowly (μ = 0.01 h
−1
) and harbored either 1 (strain KBS 83) or 2 (strain KBS 96) copies of the 16S rRNA encoding gene—a genomic characteristic typical of oligotrophs. Strain KBS 83 is a microaerophile, growing optimally at 8% oxygen. These metabolic characteristics help delineate the niches that acidobacteria occupy in soil and are consistent with their widespread distribution and abundance.
Cultivation-Independent Analysis of Bacteria in IDEXX Quanti-Tray/2000 Fecal Indicator Assays
Authors: Sercu Bram , Van De Werfhorst Laurie C. , Murray Jill L. S. , Holden Patricia A. 
Published: November 2010

ABSTRACT

Monitoring microbiological water quality is important for protecting water resources and the health of swimmers. Routine monitoring relies on cultivating fecal indicator bacteria (FIB), frequently using defined substrate technology. Defined substrate technology is designed to specifically enrich for FIB, but a complete understanding of the assay microbiology requires culture-independent analysis of the enrichments. This study aimed to identify bacteria in positive wells of Colilert and Enterolert Quanti-Tray/2000 (IDEXX Laboratories) FIB assays in environmental water samples and to quantify the degree of false-positive results for samples from an urban creek by molecular methods. Pooled
Escherichia coli
- and
Enterococcus
-positive Quanti-Tray/2000 enrichments, either from urban creek dry weather flow or municipal sewage, harbored diverse bacterial populations based on 16S rRNA gene sequences and terminal restriction fragment length polymorphism analyses. Target taxa (coliforms or enterococci) and nontarget taxa (
Vibrio
spp.,
Shewanella
spp.,
Bacteroidetes
, and
Clostridium
spp.) were identified in pooled and individual positive Colilert and Enterolert wells based on terminal restriction fragments that were in common with those generated
in silico
from clone sequences. False-positive rates of between 4 and 23% occurred for the urban creek samples, based on the absence of target terminal restriction fragments in individual positive wells. This study suggests that increased selective inhibition of nontarget bacteria could improve the accuracy of the Colilert and Enterolert assays.
Concentration and Diversity of Uncultured
Legionella
spp. in Two Unchlorinated Drinking Water Supplies with Different Concentrations of Natural Organic Matter
Authors: Wullings Bart A. , Bakker Geo , van der Kooij Dick 
Published: November 2010

ABSTRACT

Two unchlorinated drinking water supplies were investigated to assess the potential of water treatment and distribution systems to support the growth of
Legionella
spp. The treatment plant for supply A distributed treated groundwater with a low concentration (<0.5 ppm of C) of natural organic matter (NOM), and the treatment plant for supply B distributed treated groundwater with a high NOM concentration (8 ppm of C). In both supplies, the water temperature ranged from about 10°C after treatment to 18°C during distribution. The concentrations of
Legionella
spp. in distributed water, analyzed with quantitative PCR (Q-PCR), averaged 2.9 (± 1.9) × 10
2
cells liter
−1
in supply A and 2.5 (± 1.6) × 10
3
cells liter
−1
in supply B. No
Legionella
was observed with the culture method. A total of 346 clones (96 operational taxonomical units [OTUs] with ≥97% sequence similarity) were retrieved from water and biofilms of supply A and 251 (43 OTUs) from supply B. The estimation of the average value of total species richness (Chao1) in supply A (153) was clearly higher than that for supply B (58). In each supply, about 77% of the sequences showed <97% similarity to described species. Sequences related to
L. pneumophila
were only incidentally observed. The
Legionella
populations of the two supplies are divided into two distinct clusters based on distances in the phylogenetic tree as fractions of the branch length. Thus, a large variety of mostly yet-undescribed
Legionella
spp. proliferates in unchlorinated water supplies at temperatures below 18°C. The lowest concentration and greatest diversity were observed in the supply with the low NOM concentration.
Isolation and Characterization of
Shigella flexneri
G3, Capable of Effective Cellulosic Saccharification under Mesophilic Conditions
Authors: Wang Aijie , Gao Lingfang , Ren Nanqi , Xu Jifei , Liu Chong , Cao Guangli , Yu Hao , Liu Wenzong , Hemme Christopher L. , He Zhili , Zhou Jizhong 
Published: November 2010

ABSTRACT

A novel
Shigella
strain (
Shigella flexneri
G3) showing high cellulolytic activity under mesophilic, anaerobic conditions was isolated and characterized. The bacterium is Gram negative, short rod shaped, and nonmotile and displays effective production of glucose, cellobiose, and other oligosaccharides from cellulose (Avicel PH-101) under optimal conditions (40°C and pH 6.5). Approximately 75% of the cellulose was hydrolyzed in modified ATCC 1191 medium containing 0.3% cellulose, and the oligosaccharide production yield and specific production rate reached 375 mg g Avicel
−1
and 6.25 mg g Avicel
−1
h
−1
, respectively, after a 60-hour incubation. To our knowledge, this represents the highest oligosaccharide yield and specific rate from cellulose for mesophilic bacterial monocultures reported so far. The results demonstrate that
S. flexneri
G3 is capable of rapid conversion of cellulose to oligosaccharides, with potential biofuel applications under mesophilic conditions.
Polyphyletic Origin of
Vibrio vulnificus
Biotype 2 as Revealed by Sequence-Based Analysis
Authors: Sanjuán Eva , González-Candelas Fernando , Amaro Carmen 
Published: November 2010

ABSTRACT

A sequence-based analysis of seven housekeeping and virulence-related genes shows that the species
Vibrio vulnificus
is subdivided into three phylogenetic lineages that do not correspond with the biotypes and that biotype 2 is polyphyletic. These results support the reclassification of biotype 2 as a pathovar that would group the strains with pathogenic potential to develop vibriosis in fish.