bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Salt Stress on Carbohydrate Metabolism in Desert Soil Alga Microcoleus vaginatus Gom.
Authors: Chen Lan‐Zhou , Li Dun‐Hai , Song Li‐Rong , Hu Chun‐Xiang , Wang Gao‐Hong , Liu Yong‐Ding 
Published: August 2006

AbstractThe effects of salt stress on carbohydrate metabolism in Microcoleus vaginatus Gom., a cyanobacterium isolated from desert algal crusts, were investigated in the present study. Extracellular total carbohydrates and exopolysaccharides (EPS) in the culture medium produced by M. vaginatus increased significantly during the growth phase and reached a maximum during the stationary phase. The production of extracellular carbohydrates also significantly increased under higher salt concentrations, which was attributed to an increase in low molecular weight carbohydrates. In the presence of NaCl, the production of cellular total carbohydrates decreased and photosynthetic activity was impaired, whereas cellular reducing sugars, water‐soluble sugars and sucrose content and sucrose phosphate synthase activity increased, reaching a maximum in the presence of 200 mmol/L NaCl. These parameters were restored to original levels when the algae were transferred to a non‐saline medium. Sodium and K+ concentrations of stressed cells decreased significantly and H+‐ATPase activity increased after the addition of exogenous sucrose or EPS. The results suggest that EPS and sucrose are synthesized to maintain the cellular osmotic equilibrium between the intra‐ and extracellular environment, thus protecting algal cells from osmotic damage, which was attributed to the selective exclusion of cellular Na+ and K+ by H+‐ATPase.(Managing editor: Ping He)
Effect of Seasonality on Distribution of Macroalgae in a Stream System (Xin'an Spring) in Shanxi Province, North China
Authors: Hu Bian‐Fang , Xie Shu‐Lian 
Published: August 2006

AbstractA survey of the seasonal distribution of macroalgae in a stream system in Shanxi Province, north China, was undertaken from July 2004 to April 2005. The relative abundance and percentage cover of macroalgae, and several environmental factors were monitored along a 20‐m stretch at each of four sites, at intervals of approximately three months (one sampling per season). Several stream conditions were relatively constant over the sampling period (pH, maximum width and maximum depth), whereas others exhibited a distinct seasonal pattern (water temperature and specific conductance), and some fluctuated with no discernable seasonal pattern (current velocity and dissolved oxygen). Forty‐two species of macroalgae were found, with a predominance of Chlorophyta (26 species, 61.9%). Rhodophyta and Charophyta represented the smallest proportion (1 species each, 2.38%). Six macroalgae species were the most widespread, occurring in all four sampling sites. Twelve species were found at only one site each. In terms of seasonality, eight species occurred throughout the year, whereas 16 species were found in only one season each. The macroalgal community at Xin'an Spring was species rich relative to other streams. Species richness per sampling site was negatively correlated with pH. Principal component analysis revealed that no single variable had much influence on the macroalgal seasonal dynamics. We calculated Sorensen similarity indices to compare our study with other continent‐wide surveys of stream macroalgae, but the similarity indices were all very low. This study also shows that macroalgae in different locations have significant reproductive isolation.(Managing editor: Ya‐Qin Han)
Proteomic Analysis of the Response of Liangyoupeijiu (Super High‐Yield Hybrid Rice) Seedlings to Cold Stress
Authors: Yang Ping‐Fang , Li Xiao‐Juan , Liang Yu , Jing Yu‐Xiang , Shen Shi‐Hua , Kuang Ting‐Yun 
Published: August 2006

AbstractLiangyoupeijiu is a super high‐yield hybrid rice. Despite its advantages with respect to yield and grain quality, it is sensitive to cold, which keeps it from being widely cultivated. We subjected Liangyoupeijiu seedlings to 4°C cold treatment, then extracted the leaf proteins. After 2‐D gel electrophoresis separation and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry analysis, a series of differentially displayed proteins were identified. Some metabolism‐associated proteins were found among the downregulated proteins, such as carbamoyl phosphate synthetase, transketolase 1, dihydrolipoamide dehydrogenase and glyceraldehyde 3‐phosphate dehydrogenase. The upregulated proteins included both stress‐resistance proteins such as nucleoside diphosphate kinase I and proteins that are negative for rice growth, such as FtsH‐like protein, plastid fusion and/or translocation factor (Pftf) and actin. Our results indicate that cold may inhibit Liangyoupeijiu growth through decreasing metabolic activity and damaging cell structure.(Managing editor: Li‐Hui Zhao)
A Hedonic Price Analysis of Farmland Option Premiums Under Urban Influences
Authors: Isgin Tamer , Forster D. Lynn 
Published: August 2006

An emerging theory, real option pricing, suggests that an important component of urban fringe farmland values may be the option value arising from nearby urban development. This new option pricing theory, as opposed to its standard conventional counterpart in finance, incorporates both the uncertainty about the future net benefits of a land conversion decision and the irreversibility of this action taken. We demonstrate that parsimonious empirical hedonic models of the errors‐in‐variables type, when corrected for heteroskedasticity, can provide adequate representations of farmland option premiums. Data for a random sample of cash rented Ohio farmland parcels are used, and the impacts of urban development on farmland option premiums are estimated. Results provide evidence that (a) both land‐use conversion probability and urban influences have been important factors affecting the option value of the state's farmland, and (b) these option premiums associated with irreversible and uncertain land development are capitalized into farmland values.Une nouvelle théorie, l'évaluation des options réelles, semble indiquer qu'un élément important de la valeur des terres agricoles périurbaines pourrait être la valeur d'option découlant du développement urbain avoisinant. Cette nouvelle théorie, contrairement aux options financières, inclut à la fois l'incertitude quant aux bénéfices nets futurs liés à la décision de convertir une terre et l'irréversibilité de cette décision. Nous avons démontré que les modèles empiriques parcimonieux et hédoniques du type erreurs sur les variables peuvent, une fois l'hétéroscédasticité corrigée, donner des présentations adéquates des prix de l'option des terres agricoles. Nous avons utilisé les données d'un échantillon aléatoire de parcelles de terres agricoles louées au comptant en Ohio et nous avons estimé l'impact du développement urbain sur le prix de l'option des terres agricoles. Les résultats ont montré: a) que la probabilité de conversion de l'utilisation des terres et les influences urbaines sont des facteurs importants qui influent sur la valeur de l'option des terres agricoles de l'État; b) que ces prix de l'option associés à un aménagement urbain irréversible et incertain sont intégrés dans la valeur des terres agricoles.
cDNA Microarrays as a Tool for Identification of Biomineralization Proteins in the CoccolithophoridEmiliania huxleyi(Haptophyta)
Authors: Quinn Patrick , Bowers Robert M. , Zhang Xiaoyu , Wahlund Thomas M. , Fanelli Michael A. , Olszova Daniela , Read Betsy A. 
Published: August 2006

ABSTRACTMarine unicellular coccolithophore algae produce species-specific calcite scales otherwise known as coccoliths. While the coccoliths and their elaborate architecture have attracted the attention of investigators from various scientific disciplines, our knowledge of the underpinnings of the process of biomineralization in this alga is still in its infancy. The processes of calcification and coccolithogenesis are highly regulated and likely to be complex, requiring coordinated expression of many genes and pathways. In this study, we have employed cDNA microarrays to investigate changes in gene expression associated with biomineralization in the most abundant coccolithophorid,Emiliania huxleyi. Expression profiling of cultures grown under calcifying and noncalcifying conditions has been carried out using cDNA microarrays corresponding to approximately 2,300 expressed sequence tags. A total of 127 significantly up- or down-regulated transcripts were identified using aPvalue of 0.01 and a change of >2.0-fold. Real-time reverse transcriptase PCR was used to test the overall validity of the microarray data, as well as the relevance of many of the proteins predicted to be associated with biomineralization, including a novel gamma-class carbonic anhydrase (A. R. Soto, H. Zheng, D. Shoemaker, J. Rodriguez, B. A. Read, and T. M. Wahlund, Appl. Environ. Microbiol. 72:5500-5511, 2006). Differentially regulated genes include those related to cellular metabolism, ion channels, transport proteins, vesicular trafficking, and cell signaling. The putative function of the vast majority of candidate transcripts could not be defined. Nonetheless, the data described herein represent profiles of the transcription changes associated with biomineralization-related pathways inE. huxleyiand have identified novel and potentially useful targets for more detailed analysis.
Comparison of rRNA and Polar-Lipid-Derived Fatty Acid Biomarkers for Assessment of
13
C-Substrate Incorporation by Microorganisms in Marine Sediments
Authors: MacGregor Barbara J. , Boschker Henricus T. S. , Amann Rudolf 
Published: August 2006

ABSTRACT

We determined whether a recently developed method to isolate specific small-subunit (SSU) rRNAs can be used in
13
C-labeling studies to directly link community structure and function in natural ecosystems. Replicate North Sea sediment cores were incubated at the in situ temperature following addition of
13
C-labeled acetate, propionate, amino acids, or glucose. Eukaryotic and bacterial SSU rRNAs were separated from total RNA by means of biotin-labeled oligonucleotide probes and streptavidin-coated paramagnetic beads, and the
13
C content of the isolated rRNA was determined by elemental analysis-isotope ratio mass spectrometry. The SSU rRNA yield with the bead-capture protocol was improved by using helper probes. Incorporation of label into bacterial SSU rRNA was detectable after 2 h of incubation. The labeling was always much greater in bacterial SSU rRNA than in eukaryotic SSU rRNA, suggesting that bacteria were the main consumers of the
13
C-labeled compounds. Similar results were obtained with the
13
C-labeled polar-lipid-derived fatty acid (PLFA) approach, except that more label was detected in bacterial PLFA than in bacterial SSU rRNA. This may be attributable to the generally slow growth of sediment microbial populations, which results in low ribosome synthesis rates and relatively few ribosomes per cell. We discuss possible ways to improve the probe-capture protocol and the sensitivity of the
13
C analysis of the captured SSU rRNA.
Microbial Colonization and Competition on the Marine Alga
Ulva australis
Authors: Rao Dhana , Webb Jeremy S. , Kjelleberg Staffan 
Published: August 2006

ABSTRACT

Pseudalteromonas tunicata
and
Roseobacter gallaeciensis
are biofilm-forming marine bacteria that are often found in association with the surface of the green alga
Ulva australis
. They are thought to benefit the plant host by producing inhibitory compounds that are active against common fouling organisms. We investigated factors that influence the ability of
P. tunicata
and
R. gallaeciensis
to attach to and colonize the plant surface and also the competitive interactions that occur between these organisms and other isolates from
U. australis
during biofilm formation on the plant surface. A surprisingly high number of
P. tunicata
cells, at least 10
8
cells ml
−1
, were required for colonization and establishment of a population of cells that persists on axenic surfaces of
U. australis
. Factors that enhanced colonization of
P. tunicata
included inoculation in the dark and pregrowth of inocula in medium containing cellobiose as the sole carbon source (cellulose is a major surface polymer of
U. australis
). It was also found that
P. tunicata
requires the presence of a mixed microbial community to colonize effectively. In contrast,
R. gallaeciensis
effectively colonized the plant surface under all conditions tested. Studies of competitive interactions on the plant surface revealed that
P. tunicata
was numerically dominant compared with all other bacterial isolates tested (except
R. gallaeciensis
), and this dominance was linked to production of the antibacterial protein AlpP. Generally,
P. tunicata
was able to coexist with competing strains, and each strain existed as microcolonies in spatially segregated regions of the plant.
R. gallaeciensis
was numerically dominant compared with all strains tested and was able to invade and disperse preestablished biofilms. This study highlighted the fact that microbial colonization of
U. australis
surfaces is a dynamic process and demonstrated the differences in colonization strategies exhibited by the epiphytic bacteria
P. tunicata
and
R. gallaeciensis
.
Exposure to Salt and Organic Acids Increases the Ability ofListeria monocytogenesTo Invade Caco-2 Cells but Decreases Its Ability To Survive Gastric Stress
Authors: Garner Matthew R. , James Karen E. , Callahan Michelle C. , Wiedmann Martin , Boor Kathryn J. 
Published: August 2006

ABSTRACTThe effects of environmental stress exposure onListeria monocytogenesgrowth and virulence-associated characteristics were investigated. Specifically, we measured the effects of temperature (7 or 37°C), pH (5.5 or 7.4), the presence of salt and organic acids (375 mM NaCl, 8.45 mM sodium diacetate [SD], 275 mM sodium lactate [SL], or a combination of NaCl, SD, and SL), and deletion ofsigB, which encodes a key stress response regulator, on the ability ofL. monocytogenesto grow, invade Caco-2 cells, and survive exposure to synthetic gastric fluid (pH 2.5 or 4.5). Our results indicate that (i)L. monocytogeneslog-phase generation times and maximum cell numbers are not dependent on the alternative sigma factor σBin the presence of NaCl and organic acids at concentrations typically found in foods; (ii) growth inhibition ofL. monocytogenesthrough the addition of organic acids is pH dependent; (iii) the ability ofL. monocytogenesto invade Caco-2 cells is affected by growth phase, temperature, and the presence of salt and organic acids, with the highest relative invasion capabilities observed for cells grown with SL or NaCl at 37°C and pH 7.4; (iv) growth ofL. monocytogenesin the presence of NaCl, SD, or SL reduces its ability to survive exposure to gastric fluid; and (v) exposure ofL. monocytogenesto gastric fluid reduces the enhanced invasiveness caused by growth in the presence of NaCl or SL. These findings suggest that virulence-associated characteristics that determine theL. monocytogenesinfectious dose are likely to be affected by food-specific properties (e.g., pH or the presence of salt or organic acid).
Measurement of Biocolloid Collision Efficiencies for Granular Activated Carbon by Use of a Two-Layer Filtration Model
Authors: Paramonova Ekaterina , Zerfoss Erica L. , Logan Bruce E. 
Published: August 2006

ABSTRACT

Point-of-use filters containing granular activated carbon (GAC) are an effective method for removing certain chemicals from water, but their ability to remove bacteria and viruses has been relatively untested. Collision efficiencies (α) were determined using clean-bed filtration theory for two bacteria (
Raoutella terrigena
33257 and
Escherichia coli
25922), a bacteriophage (MS2), and latex microspheres for four GAC samples. These GAC samples had particle size distributions that were bimodal, but only a single particle diameter can be used in the filtration equation. Therefore, consistent with previous reports, we used a particle diameter based on the smallest diameter of the particles (derived from the projected areas of 10% of the smallest particles). The bacterial collision efficiencies calculated using the filtration model were high (0.8 ≤ α ≤ 4.9), indicating that GAC was an effective capture material. Collision efficiencies greater than unity reflect an underestimation of the collision frequency, likely as a result of particle roughness and wide GAC size distributions. The collision efficiencies for microspheres (0.7 ≤ α ≤ 3.5) were similar to those obtained for bacteria, suggesting that the microspheres were a reasonable surrogate for the bacteria. The bacteriophage collision efficiencies ranged from ≥0.2 to ≤0.4. The predicted levels of removal for 1-cm-thick carbon beds ranged from 0.8 to 3 log for the bacteria and from 0.3 to 1.0 log for the phage. These tests demonstrated that GAC can be an effective material for removal of bacteria and phage and that GAC particle size is a more important factor than relative stickiness for effective particle removal.
HER2, TOP2A, CCND1, EGFR and C-MYC oncogene amplification in colorectal cancer
Authors: Al-Kuraya Khawla , Novotny Hedvika , Bavi Prashant , Siraj Abdul K , Uddin Shahab , Ezzat Adnan , Sanea Nasser Al , Al-Dayel Fouad , Al-Mana Hadeel , Sheikh Salwa S , Mirlacher Martina , Tapia Coya , Simon Ronald , Sauter Guido , Terracciano Luigi , Tornillo Luigi 
Published: August 2006

Aim:Recent studies had suggested substantial molecular differences between tumours from different ethnic groups. In this study, the molecular differences between the incidences of colorectal carcinoma in Saudi and Swiss populations are investigated.Method:518 cases of colon cancer tumours (114 from Saudi Arabia and 404 from Switzerland) were analysed in a tissue microarray format. Fluorescence in situ hybridisation (FISH) was used to estimate frequencies of copy number changes of known oncogenes, including HER2, TOPO2A, CCND1, EGFR and C-MYC.Results:Using FISH, amplifications were mostly low level (gene-to-centromere ratio 2 to 4), which is in contrast with other tumour types with more frequent gene amplifications. The amplifications were particularly frequent for MYC (Saudi 9% and Swiss 14.2%) but unrelated to clinical outcome and pathological information. Remarkably, there were four tumours exhibiting classic high-level gene amplification for HER2 (Swiss 1.3%), a pattern often accompanied by response to trastuzumab (Herceptin) in breast cancer. Occasional high-level amplifications were also observed for CCND1 (Saudi 1/106, 0.9%; Swiss 2/373, 0.5%) and EGFR (Swiss 2/355; 0.6%).Conclusions:Rare high-level amplifications of therapeutic target genes were found in patients with colon cancer. Although no molecular differences were found between incidences of colon cancer cases in Swiss and Saudi populations, these observations emphasise the urgent need for clinical studies investigating the effect of targeted therapies.
SPARC Represses E-Cadherin and Induces Mesenchymal Transition during Melanoma Development
Authors: Robert Guillaume , Gaggioli Cédric , Bailet Olivier , Chavey Carine , Abbe Patricia , Aberdam Edith , Sabatié Emilie , Cano Amparo , Garcia de Herreros Antonio , Ballotti Robert , Tartare-Deckert Sophie 
Published: August 2006

Abstract
During progression of melanoma, loss of the cell-cell adhesion molecule E-cadherin contributes to uncontrolled growth and invasive behavior of transformed melanocytes. Secreted protein acidic and rich in cysteine (SPARC) is a nonstructural matricellular protein that regulates cell-matrix interactions leading to alterations in cell adhesion and proliferation. Overexpression of SPARC has been associated with progression of various cancers, including melanoma; however, its role in primary tumor development is not well defined. We show that normal human melanocytes overexpressing SPARC adopt a fibroblast-like morphology, concomitant with loss of E-cadherin and P-cadherin expression, and increased expression of mesenchymal markers. Concurrent with these changes, SPARC expression stimulates melanocyte motility and melanoma cell invasion. Expression of SPARC results in transcriptional down-regulation of E-cadherin that correlates with induction of Snail, a repressor of E-cadherin. Conversely, SPARC depletion leads to up-regulation of E-cadherin and reduces Snail levels, and SPARC-null cells exhibit a marked change in their mesenchymal phenotype. Finally, analysis of SPARC, Snail, and E-cadherin levels in melanocytes and malignant melanoma cell lines further supports the functional relationship among these proteins during melanoma progression. Our findings provide evidence for the role of SPARC in early transformation of melanocytes and identify a novel mechanism, whereby tumor-derived SPARC promotes tumorigenesis by mediating Snail induction and E-cadherin suppression. (Cancer Res 2006; 66(15): 7516-23)
In vivoBiological Activity of the Histone Deacetylase Inhibitor LAQ824 Is detectable with 3′-Deoxy-3′-[18F]Fluorothymidine Positron Emission Tomography
Authors: Leyton Julius , Alao John P. , Da Costa Marco , Stavropoulou Alexandra V. , Latigo John R. , Perumal Meg , Pillai Radhakrishna , He Qimin , Atadja Peter , Lam Eric W.-F. , Workman Paul , Vigushin David M. , Aboagye Eric O. 
Published: August 2006

AbstractHistone deacetylase inhibitors (HDACI) are emerging as growth inhibitory compounds that modulate gene expression and inhibit tumor cell proliferation. We assessed whether 3′-deoxy-3′-[18F]fluorothymidine–positron emission tomography ([18F]FLT-PET) could be used to noninvasively measure the biological activity of a novel HDACI LAQ824 in vivo. We initially showed that thymidine kinase 1 (TK1; EC2.7.1.21), the enzyme responsible for [18F]FLT retention in cells, was regulated by LAQ824 in a drug concentration–dependent manner in vitro. In HCT116 colon carcinoma xenograft–bearing mice, LAQ824 significantly decreased tumor [18F]FLT uptake in a dose-dependent manner. At day 4 of treatment, [18F]FLT tumor-to-heart ratios at 60 minutes (NUV60) were 2.16 ± 0.15, 1.86 ± 0.13, and 1.45 ± 0.20 in vehicle, and 5 and 25 mg/kg LAQ824 treatment groups, respectively (P ≤ 0.05). LAQ825 at 5 mg/kg also significantly reduced both TK1 levels and [18F]FLT uptake at day 10 but not at day 2 (P ≤ 0.05). [18F]FLT NUV60 correlated significantly with cellular proliferation (r = 0.68; P = 0.0019) and was associated with drug-induced histone H4 hyperacetylation. Of interest to [18F]FLT-PET imaging, both TK1 mRNA copy numbers and protein levels decreased in the order vehicle &gt;5 mg/kg LAQ824 &gt; 25 mg/kg LAQ824, providing a rationale for the use of [18F]FLT-PET in this setting. We also observed increases in Rb hypophosphorylation and p21 levels, factors that could have contributed to the alteration in TK1 transcription in vivo. In conclusion, we have shown the utility of [18F]FLT-PET for monitoring the biological activity of the HDACI, LAQ824. Drug-induced changes in tumor [18F]FLT uptake were due, at least in part, to reductions in TK1 transcription and translation. (Cancer Res 2006; 66(15): 7621-9)