bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reduced EBF expression underlies loss of B‐cell potential of hematopoietic progenitors with age
Authors: Lescale Chloé , Dias Sheila , Maës Jérôme , Cumano Ana , Szabo Paul , Charron Dominique , Weksler Marc E. , Dosquet Christine , Vieira Paulo , Goodhardt Michele 
Published: March 2010

SummaryAging is accompanied by a reduction in the generation of B lymphocytes leading to impaired immune responses. In this study, we have investigated whether the decline in B lymphopoiesis is due to age‐related defects in the hematopoietic stem cell compartment. The ability of hematopoietic stem cells from old mice to generate B cells, as measured in vitro, is decreased 2–5‐fold, while myeloid potential remains unchanged. This age‐related decrease in B‐cell potential is more marked in common lymphoid progenitors (CLP) and was associated with reduced expression of the B‐lineage specifying factors, EBF and Pax5. Notably, retrovirus‐mediated expression of EBF complemented the age‐related loss of B‐cell potential in CLP isolated from old mice. Furthermore, transduction of CLP from old mice with a constitutively active form of STAT5 restored both EBF and Pax5 expression and increased B‐cell potential. These results are consistent with a mechanism, whereby reduced expression of EBF with age decreases the frequency with which multipotent hematopoietic progenitors commit to a B‐cell fate, without altering their potential to generate myeloid cells.
Ionizing radiation‐induced long‐term expression of senescence markers in mice is independent of p53 and immune status
Authors: Le Oanh N. L. , Rodier Francis , Fontaine Francois , Coppe Jean‐Philippe , Campisi Judith , DeGregori James , Laverdière Caroline , Kokta Victor , Haddad Elie , Beauséjour Christian M. 
Published: March 2010

SummaryExposure to IR has been shown to induce the formation of senescence markers, a phenotype that coincides with lifelong delayed repair and regeneration of irradiated tissues. We hypothesized that IR‐induced senescence markers could persist long‐term in vivo, possibly contributing to the permanent reduction in tissue functionality. Here, we show that mouse tissues exposed to a sublethal dose of IR display persistent (up to 45 weeks, the maximum time analyzed) DNA damage foci and increased p16INK4a expression, two hallmarks of cellular senescence and aging. BrdU‐labeling experiments revealed that IR‐induced damaged cells are preferentially eliminated, at least partially, in a tissue‐dependent manner. Unexpectedly, the accumulation of damaged cells was found to occur independent from the DNA damage response modulator p53, and from an intact immune system, as their levels were similar in wild‐type and Rag2−/− γC−/− mice, the latter being deficient in T, B, and NK cells. Together, our results provide compelling evidence that exposure to IR induces long‐term expression of senescence markers in vivo, an effect that may contribute to the reduced tissue functionality observed in cancer survivors.
The load of short telomeres, estimated by a new method, Universal STELA, correlates with number of senescent cells
Authors: Bendix Laila , Horn Peer Bendix , Jensen Uffe Birk , Rubelj Ivica , Kolvraa Steen 
Published: March 2010

SummaryShort telomeres are thought to trigger senescence, most likely through a single – or a group of few – critically shortened telomeres. Such short telomeres are thought to result from a combination of gradual linear shortening resulting from the end replication problem, reflecting the division history of the cell, superimposed by a more stochastic mechanism, suddenly causing a significant shortening of a single telomere. Previously, studies that have tried to explore the role of critically shortened telomeres have been hampered by methodological problems. With the method presented here, Universal STELA, we have a tool that can directly investigate the relationship between senescence and the load of short telomeres. The method is a variant of the chromosome‐specific STELA method but has the advantage that it can demonstrate short telomeres regardless of chromosome. With Universal STELA, we find a strong correlation between the load of short telomeres and cellular senescence. Further we show that the load of short telomeres is higher in senescent cells compared to proliferating cells at the same passage, offering an explanation of premature cell senescence. This new method, Universal STELA, offers some advantages compared to existing methods and can be used to explore many of the unanswered questions in telomere biology including the role that telomeres play in cancer and aging.
Records of bizarre Jurassic brachycerans in the Daohugou biota, China (Diptera, Brachycera, Archisargidae and Rhagionemestriidae)
Authors: ZHANG JUN FENG 
Published: March 2010

Abstract: Four new Brachycera fossils were collected from the Daohugou biota, China. Among these, two impressions demonstrating peculiar wing venation can be designated as two new species of a new genus (Mostovskisargus portentosusgen. et sp. nov. andM. signatussp. nov.) referred to a new subfamily Mostovskisarginae (subfam. nov.) within Archisargidae. The third impression belongs to a new species (Calosargus(Pterosargus)sinicussp. nov.) referred to the subgenusPterosargusMostovski, 1997 ofCalosargusMostovski, 1997 within Archisarginae, Archisargidae. It is only the second member of the subgenusPterosargusworldwide. The fourth impression is a nearly complete fly,Jurassinemestrinus orientalisgen. et sp. nov. referable to Rhagionemestriidae. It reveals new morphological data about rhagionemestriids and extends the geographical distribution of this group beyond Europe and Central Asia during the Mesozoic. A correlation for the archisargid composition of taxa in Daohugou and Karabastau formations is discussed. The age of the fly‐bearing strata is briefly reassessed and can be more accurately limited to the Callovian–Oxfordian based on both biostratigraphical correlation and radiometric dating.
Earnings Trend and Performance Relative to Benchmarks: How Consistency Influences Their Joint Use
Authors: KOONCE LISA , LIPE MARLYS GASCHO 
Published: March 2010

ABSTRACTArchival research shows that the market reacts to earnings trend as well as to earnings performance relative to analysts' forecasts (i.e., benchmark performance). We conduct four experiments to investigate how and why investors react to these two measures when both are available over multiple time periods. Our results show that investors rely on an earnings measure only when it is consistent over time. When both measures are consistent over time, investors use them in an additive fashion, suggesting that they view them as providing different information about the firm. Further tests show that investors believe that earnings trend and benchmark performance both provide information about a firm's future prospects and management's credibility. Although judged future prospects fully explain the effect of earnings trend on investor judgments, neither judged future prospects nor management credibility completely explains the effect of benchmark performance. Our study has implications for firm managers and researchers.
Biochemical Characterization of Soluble Acid and Alkaline Invertases from Shoots of Etiolated Pea Seedlings
Authors: Kim Donggiun , Park So Yun , Chung Youngjae , Park Jongbum , Lee Sukchan , Lee Taek‐Kyun 
Published: March 2010

Abstract Soluble invertase was purified from pea (Pisum sativum L.) by sequential procedures entailing ammonium sulfate precipitation, DEAE‐Sepharose column, Con‐A‐ and Green 19‐Sepharose affinity columns, hydroxyapatite column, ultra‐filtration, and Sephacryl 300 gel filtration. The purified soluble acid (SAC) and alkaline (SALK) invertases had a pH optimum of 5.3 and 7.3, respectively. The temperature optimum of two invertases was 37 °C. The effects of various concentrations of Tris‐HCl, HgCl2, and CuSO4 on the activities of the two purified enzymes were examined. Tris‐HCl and HgCl2 did not affect SAC activity, whereas 10 mM Tris‐HCl and 0.05 mM HgCl2 inhibited SALK activity by about 50%. SAC and SALK were inhibited by 4.8 mM and 0.6 mM CuSO4 by 50%, respectively. The enzymes display typical hyperbolic saturation kinetics for sucrose hydrolysis. The Kms of SAC and SALK were determined to be 1.8 and 38.6 mM, respectively. The molecular masses of SAC shown by sodium dodecyl sulfate–polyacrylamide gel electrophoresis and immunoblotting were 22 kDa and 45 kDa. The molecular mass of SALK was 30 kDa. Iso‐electric points of the SAC and SALK were estimated to be about pH 7.0 and pH 5.7, respectively.
The mammalian KIR2.x inward rectifier ion channel family: expression pattern and pathophysiology
Authors: De Boer T. P. , Houtman M. J. C. , Compier M. , Van Der Heyden M. A. G. 
Published: March 2010

AbstractInward rectifier currents based on KIR2.x subunits are regarded as essential components for establishing a stable and negative resting membrane potential in many excitable cell types. Pharmacological inhibition, null mutation in mice and dominant positive and negative mutations in patients reveal some of the important functions of these channels in their native tissues. Here we review the complex mammalian expression pattern of KIR2.x subunits and relate these to the outcomes of functional inhibition of the resultant channels. Correlations between expression and function in muscle and bone tissue are observed, while we recognize a discrepancy between neuronal expression and function.
Migration of Antimicrobial Silver from Composites of Polylactide with Silver Zeolites
Authors: Fernández Avelina , Soriano Eva , Hernández‐Muñoz Pilar , Gavara Rafael 
Published: March 2010

ABSTRACT:  Silver ion migration and antimicrobial activity of PLA (polylactic acid‐polylactide)/silver zeolite composites were investigated. Films prepared by solution‐casting/solvent evaporation, or by melt‐mixing/compression molding were compared. Silver migration to food simulants and TSB (tryptone soy broth) was quantified at different temperatures. Antimicrobial activity against Staphylococcus aureus and Escherichia coli was measured following the Japanese Industrial Standard JIS Z 2801. All types of PLA/silver zeolite composites released Ag+ ions. A more intense ionic exchange with the zeolites and a significant, but low, antimicrobial activity in solution were found in cast films. To attain antimicrobial effects, however, migrated ions ought to be in the range of the legal limit of 0.05 mg Ag+/kg food stated by the European Food Safety Agency (EFSA). Silver migration and antimicrobial activity were sensitive to the methodology chosen to process the PLA films, the ionic strength of the medium, and the ion motility in the polymer matrix.Practical Application: Silver exchanged zeolites incorporated in food contact polymers are gaining importance as antimicrobial agents. Migration of silver ions from polymer matrices, however, is legally restricted. Therefore a compromise between silver migration and antimicrobial activity needs to be critically analyzed to validate novel materials in food packaging applications.
Kuwait: Elections and Issues of Democratization in a Middle Eastern State
Authors: Ghabra Shafeeq 
Published: March 2010

AbstractIn 1992, elections were held in Kuwait to vote for the four‐year assembly. The elections were essentially a compromise formula between two systems and political cultures in Kuwait: traditional hereditary rule and representative and modern forms. The successful conclusion of the election campaign, one of the most intensive in the history of Kuwait, may be the first step in the direction of much‐needed political reform that may tilt the country more and more toward a true parliamentary system.The elections resulted in a victory for the opposition forces and their supporters, who together won thirty‐five seats. For the first time in the history of Kuwait, government ministers can vote in parliament against a government‐backed policy, should they feel the need to do so. Kuwait, as far as conditions allow today, is progressively shifting toward a parliamentary system. But, despite Kuwait's political steps forward, many questions and immense dangers still surround the democratic process.
Librarianship in Kuwait after the Gulf War
Authors: Abdel‐Motey Yaser Y. , Al‐Hmood Nahla 
Published: March 2010

AbstractA general view of the field of librarianship in Kuwait is presented with special emphasis on the impact of the Iraqi aggression on libraries and information centers in the country.First, a review of the damages and future plans of the main library and information sectors is presented (school, public, academic, central libraries), followed by a summary of the effect of the Iraqi occupation on education in library and information science.
Planned International Technology Transfer:
Authors: Thompson Chris 
Published: March 2010

AbstractSince the mid‐1980s, Saudi Arabia has required that a percentage of all defense contracts awarded to foreign suppliers be reinvested back in the kingdom into new technology companies. The result has been three “economic offset” programs, encompassing Western defense producers and their home‐country governments in the world's largest example of planned international technology transfer.This paper reviews the three main Saudi offsets—attached to the Peace Shield (United States), al‐Yamamah (United Kingdom) and Sawari (France) arms deals—for their genesis, operations, achievements, and problems, using interviews with participants and statistical data on companies formed. It then attempts some evaluation of them against their own original explicit and implicit goals, and draws out some lessons and implications.
The Impact of Social and Psychological Factors on Car accidents in Kuwait
Authors: Alsaleh Amer 
Published: March 2010

AbstractThe objective of study was to identify select demographic, driving habits, aggressive driving, road rage and risk factors associated with involvement in road traffic accidents (RTAs) among young Kuwaiti drivers. Logistic linear regression tests these factors according to the Modified Youth Risk Behavior scales. The total sample of this study was 1619 Kuwaiti drivers, aged 18–30 years. The source for the sample consisted of self‐reported young drivers who were selected from high schools and universities in the six governorates in Kuwait. For the purposes of this study, the author defined cases (N=984) as drivers who reported being involved in a car crash during their lifetime. Controls (N=635) were identified as those drivers who were never involved in a car crash during the same period. The sample was selected during an eight‐month period, from November 2004 to June 2005.Logistic linear regression results showed that driving habits, aggressive driving, and road rage situations would result in high rates in sensation, anxiety and anger, which leads to risky driving behavior (e.g. drivers forcing a car off the road, deliberate obstruction, running red lights, running stop signs, and tailgating), which leads to involvement in traffic accidents.
Enhancement of Biofilm Formation by Subinhibitory Concentrations of Macrolides in
icaADBC-
Positive and -Negative Clinical Isolates of
Staphylococcus epidermidis
Authors: Wang Qian , Sun Feng-Jun , Liu Yao , Xiong Li-Rong , Xie Lin-Li , Xia Pei-Yuan 
Published: March 2010

ABSTRACT

Biofilm formation in
Staphylococcus epidermidis
is mediated by
icaADBC
-dependent and -independent pathways. Subinhibitory concentrations of erythromycin, azithromycin, and clarithromycin enhanced, in a dose-dependent manner, the level of biofilm formation by 20% (21/105 isolates) by macrolide-resistant
ica
-positive and -negative isolates tested
in vitro
. The presence of
ica
, however, apparently produced an enhanced effect on biofilm formation. The levels of expression of the biofilm-related genes
icaA
,
atlE
,
fruA
,
pyrR
,
sarA
, and
sigB
were increased in response to erythromycin. The results likely underscore the potential clinical relevance of macrolide-induced biofilm growth.
Nucleotide Selectivity of Antibiotic Kinases
Authors: Shakya Tushar , Wright Gerard D. 
Published: March 2010

ABSTRACT

Antibiotic kinases, which include aminoglycoside and macrolide phosphotransferases (APHs and MPHs), pose a serious threat to currently used antimicrobial therapies. These enzymes show structural and functional homology with Ser/Thr/Tyr kinases, which is suggestive of a common ancestor. Surprisingly, recent
in
vitro
studies using purified antibiotic kinase enzymes have revealed that a number are able to utilize GTP as the antibiotic phospho donor, either preferentially or exclusively compared to ATP, the canonical phosphate donor in most biochemical reactions. To further explore this phenomenon, we examined three enzymes, APH(3′)-IIIa, APH(2″)-Ib, and MPH(2′)-I, using a competitive assay that mimics
in
vivo
nucleotide triphosphate (NTP) concentrations and usage by each enzyme. Downstream analysis of reaction products by high-performance liquid chromatography enabled the determination of partitioning of phosphate flux from NTP donors to antibiotics. Using this ratio along with support from kinetic analysis and inhibitor studies, we find that under physiologic concentrations of NTPs, APH(3′)-IIIa exclusively uses ATP, MPH(2′)-I exclusively uses GTP, and APH(2″)-Ib is able to use both species with a preference for GTP. These differences reveal likely different pathways in antibiotic resistance enzyme evolution and can be exploited in selective inhibitor design to counteract resistance.
Controlled Release of Protein from Viable
Lactococcus lactis
Cells
Authors: Stentz Régis , Bongaerts Roy J. , Gunning A. Patrick , Gasson Mike , Shearman Claire 
Published: March 2010

ABSTRACT

Overexpression of the lactococcal CsiA protein affects the cell wall integrity of growing cells and leads to leakage of intracellular material. This property was optimized and exploited for the targeted release of biologically active compounds into the extracellular environment, thereby providing a new delivery system for bacterial proteins and peptides. The effects of different levels of CsiA expression on the leakage of endogenous lactate dehydrogenase and nucleic acids were measured and related to the impact of CsiA expression on
Lactococcus lactis
cell viability and growth. A leakage phenotype was obtained from cells expressing both recombinant and nonrecombinant forms of CsiA. As proof of principle, we demonstrated that CsiA promotes the efficient release of the heterologous
Listeria
bacteriophage endolysin LM4 in its active form. Under optimized conditions, native and heterologous active-molecule release is possible without affecting cell viability. The ability of CsiA to release intracellular material by controlled lysis without the requirement for an external lytic agent provides a technology for the control of both the extent of lysis and its timing. Taken together, these results demonstrate the potential of this novel approach for applications including product recovery in industrial fermentations, food processing, and medical therapy.
Biogeography and Biodiversity in Sulfide Structures of Active and Inactive Vents at Deep-Sea Hydrothermal Fields of the Southern Mariana Trough
Authors: Kato Shingo , Takano Yoshinori , Kakegawa Takeshi , Oba Hironori , Inoue Kazuhiko , Kobayashi Chiyori , Utsumi Motoo , Marumo Katsumi , Kobayashi Kensei , Ito Yuki , Ishibashi Jun-ichiro , Yamagishi Akihiko 
Published: March 2010

ABSTRACT

The abundance, diversity, activity, and composition of microbial communities in sulfide structures both of active and inactive vents were investigated by culture-independent methods. These sulfide structures were collected at four hydrothermal fields, both on- and off-axis of the back-arc spreading center of the Southern Mariana Trough. The microbial abundance and activity in the samples were determined by analyzing total organic content, enzymatic activity, and copy number of the 16S rRNA gene. To assess the diversity and composition of the microbial communities, 16S rRNA gene clone libraries including bacterial and archaeal phylotypes were constructed from the sulfide structures. Despite the differences in the geological settings among the sampling points, phylotypes related to the
Epsilonproteobacteria
and cultured hyperthermophilic archaea were abundant in the libraries from the samples of active vents. In contrast, the relative abundance of these phylotypes was extremely low in the libraries from the samples of inactive vents. These results suggest that the composition of microbial communities within sulfide structures dramatically changes depending on the degree of hydrothermal activity, which was supported by statistical analyses. Comparative analyses suggest that the abundance, activity and diversity of microbial communities within sulfide structures of inactive vents are likely to be comparable to or higher than those in active vent structures, even though the microbial community composition is different between these two types of vents. The microbial community compositions in the sulfide structures of inactive vents were similar to those in seafloor basaltic rocks rather than those in marine sediments or the sulfide structures of active vents, suggesting that the microbial community compositions on the seafloor may be constrained by the available energy sources. Our findings provide helpful information for understanding the biogeography, biodiversity and microbial ecosystems in marine environments.
Nested PCR and New Primers for Analysis of Sulfate-Reducing Bacteria in Low-Cell-Biomass Environments
Authors: Giloteaux Ludovic , Goñi-Urriza Marisol , Duran Robert 
Published: March 2010

ABSTRACT

New primers were designed for the amplification of
dsrAB
genes by nested PCR to investigate the diversity of sulfate-reducing prokaryotes (SRP) in environments with low bacterial cell density. The success of the nested PCR for the determination of SRP diversity was estimated by terminal-restriction fragment length polymorphism analysis in the Reigous, a small creek at an inactive mine (Carnoulès, France), which constitutes an extreme acidic arsenic-rich environment. Nested PCR limits were evaluated in
dsrAB
-rich sediments, and this technique was compared to direct PCR using either known primers (DSR1F/DSR4R) or new primers (dsr619AF/dsr1905BR). The comparison of clone libraries revealed that, even if the levels of diversity observed were not identical, nested PCR did not reduce the diversity compared to that of direct DSR1F/DSR4R PCR. Clone sequences were affiliated mainly with the
Desulfobacteraceae
and
Desulfohalobiaceae
families. Many sequences (∼30%) were related to a deeply branching lineage unaffiliated with any cultured SRP. Although this
dsrAB
cluster was found in all libraries, the new primers better amplified this lineage, providing more information on this unknown bacterial group. Thanks to these new primers in nested PCR, the SRP community from Carnoulès could be characterized. Specific SRP populations were obtained according to environmental characteristics.
Desulfomicrobiaceae
-related sequences were recovered in samples with low pH, low levels of dissolved oxygen, and high As content, while sequences belonging to the deeply branching group were found in a less extreme sample. Furthermore, for the first time,
dsrAB
sequences related to the latter group were recovered from freshwater.