bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seed‐specific expression of a bacterial phosphoenolpyruvate carboxylase inVicia narbonensisincreases protein content and improves carbon economy
Authors: Rolletschek Hardy , Borisjuk Ljudmilla , Radchuk Ruslana , Miranda Manoela , Heim Ute , Wobus Ulrich , Weber Hans 
Published: April 2004

SummaryAn ambitious aim in plant breeding and biotechnology is to increase the protein content of crop seeds used for food and feed. Using an approach to manipulate assimilate partitioning, we succeeded in elevating the protein content in legume seeds up to 50%. Transgenic bean plants were generated which express aCorynebacterium glutamicumphosphoenolpyruvate carboxylase (PEPC) in a seed‐specific manner. The bacterial enzyme was not feedback inhibited by malate. Transgenic seeds showed a higher [14C]‐CO2uptake and about a threefold increased incorporation of labelled carbon into proteins. Changed metabolite profiles of maturing cotyledons indicated a shift of metabolic fluxes from sugars/starch into organic acids and free amino acids. These changes were consistent with an increased carbon flow through the anaplerotic pathway catalysed by PEPC. Consequently, transgenic seeds accumulated up to 20% more protein per gram seed dry weight. Additionally, seed dry weight was higher by 20%−30%. We conclude that PEPC in seeds is a promising target for molecular plant breeding.
Efficient cloning of plant genomes into bacterial artificial chromosome (BAC) libraries with larger and more uniform insert size
Authors: Chalhoub Boulos , Belcram Harry , Caboche Michel 
Published: April 2004

SummaryThe construction of bacterial artificial chromosome (BAC) libraries remains relatively complex and laborious, such that any technological improvement is considered to be highly advantageous. In this study, we addressed several aspects that improved the quality and efficiency of cloning of plant genomes into BACs. We set the ‘single tube vector’ preparation method with no precipitation or gel electrophoresis steps, which resulted in less vector DNA damage and a remarkable two‐ to threefold higher transformation efficiency compared with other known vector preparation methods. We used a reduced amount of DNA for partial digestion (up to 5 µg), which resulted in less BAC clones with small inserts. We performed electrophoresis in 0.25 × TBE (Tris, boric acid, ethylenediaminetetraacetic acid) buffer instead of 0.5 × TBE, which resulted in larger and more uniformly sized BAC inserts and, surprisingly, a two‐ to threefold higher transformation efficiency, probably due to less contamination with borate ions. We adopted a triple size selection that resulted in an increased mean insert size of up to 70 kb and a transformation efficiency comparable with that of double size selection. Overall, the improved protocol presented in this study resulted in a five‐ to sixfold higher cloning efficiency and larger and more uniformly sized BAC inserts. BAC libraries with the desired mean insert size (up to 200 kb) were constructed from several plant species, including hexaploid wheat. The improved protocol will render the construction of BAC libraries more available in plants and will greatly enhance genome analysis, gene mapping and cloning.
Expression of Vitreoscilla haemoglobin in tobacco cell cultures relieves nitrosative stress in vivo and protects from NO in vitro
Authors: Frey Alexander D. , Oberle Bettina T. , Farrés Judith , Kallio Pauli T. 
Published: April 2004

SummaryTargeted expression of Vitreoscilla haemoglobin (VHb) has been analysed in Nicotiana tabacum plants and suspension cultures under various growth and stress conditions. VHb localization to different cell compartments (cytoplasm, chloroplast and mitochondria) was successful, as judged by signal peptide cleavage. The presence of VHb in subcellular compartments did not result in phenotypical differences between these plant lines. In contrast with previous reports, we were unable to discern any significant changes in growth and other phenotypical characteristics between VHb‐expressing and transformed control plants under standard growth conditions. When exposed to nitrosative stress, growth of VHb‐expressing cultures was less affected relative to transformed controls. Furthermore, a diminished inactivation of the NO‐sensitive enzyme aconitase was observed in the presence of VHb. In contrast, no protective effect of VHb expression against oxidative stress could be detected.
Inflammation as a cause of malnutrition, atherosclerotic cardiovascular disease, and poor outcome in hemodialysis patients
Authors: Yao Qiang , Lindholm Bengt , Stenvinkel Peter 
Published: April 2004

AbstractCardiovascular disease (CVD) remains the major cause of morbidity and mortality in end‐stage renal disease (ESRD) patients treated by hemodialysis (HD). Although traditional risk factors are common in dialysis patients, they may not alone be sufficient to account for the unacceptable high prevalence of CVD in this patient group. Recent evidence demonstrates that chronic inflammation, a nontraditional risk factor that is commonly observed in HD patients, may cause malnutrition and progressive atherosclerotic CVD by several pathogenetic mechanisms. The cause(s) of inflammation in HD patients is multifactorial and includes both dialysis‐related (such as graft and fistula infections, bioincompatibility, impure dialysate, and back‐filtration) and dialysis‐unrelated factors. Although inflammation may reflect underlying CVD, an acute‐phase reaction may also be a direct cause of vascular injury. Available data suggest that proinflammatory cytokines play a central role in the genesis of both malnutrition and CVD in ESRD. Thus, it could be speculated that suppression of the vicious cycle of malnutrition, inflammation, and atherosclerosis (MIA syndrome) would improve survival in dialysis patients. As there is not yet any recognized, or even proposed, targeted treatment for ESRD patients with chronic inflammation; it would be of considerable interest to study the long‐term effect of various anti‐inflammatory treatment strategies on nutritional and cardiovascular status as well as outcome in these patients.
Biological Effects of Short-Term or Prolonged Administration of 9-[2-(Phosphonomethoxy)Propyl]Adenine (Tenofovir) to Newborn and Infant Rhesus Macaques
Authors: Van Rompay Koen K. A. , Brignolo Laurie L. , Meyer Dennis J. , Jerome Christopher , Tarara Ross , Spinner Abigail , Hamilton Marta , Hirst Linda L. , Bennett David R. , Canfield Don R. , Dearman Trish G. , Von Morgenland Wilhelm , Allen Phil C. , Valverde Celia , Castillo Alesha B. , Martin R. Bruce , Samii Valerie F. , Bendele Ray , Desjardins John , Marthas Marta L. , Pedersen Niels C. , Bischofberger Norbert 
Published: April 2004

ABSTRACTThe reverse transcriptase inhibitor 9-[2-(phosphonomethoxy)propyl]adenine (PMPA; tenofovir) was previously found to offer strong prophylactic and therapeutic benefits in an infant macaque model of pediatric human immunodeficiency virus (HIV) infection. We now summarize the toxicity and safety of PMPA in these studies. When a range of PMPA doses (4 to 30 mg/kg of body weight administered subcutaneously once daily) was administered to 39 infant macaques for a short period of time (range, 1 day to 12 weeks), no adverse effects on their health or growth were observed; this included a subset of 12 animals which were monitored for more than 2 years. In contrast, daily administration of a high dose of PMPA (30 mg/kg subcutaneously) for prolonged periods of time (>8 to 21 months) to 13 animals resulted in a Fanconi-like syndrome (proximal renal tubular disorder) with glucosuria, aminoaciduria, hypophosphatemia, growth restriction, bone pathology (osteomalacia), and reduced clearance of PMPA. The adverse effects were reversible or were alleviated following either complete withdrawal of PMPA treatment or reduction of the daily regimen from 30 mg/kg to 2.5 to 10 mg/kg subcutaneously. Finally, to evaluate the safety of a prolonged low-dose treatment regimen, two newborn macaques were started on a 10-mg/kg/day subcutaneous regimen; these animals are healthy and have normal bone density and growth after 5 years of daily treatment. In conclusion, our findings suggest that chronic daily administration of a high dose of PMPA results in adverse effects on kidney and bone, while short-term administration of relatively high doses and prolonged low-dose administration are safe.
Variety of β-Lactamases Produced by Amoxicillin-Clavulanate-Resistant
Escherichia coli
Isolated in the Northeastern United States
Authors: Kaye Keith S. , Gold Howard S. , Schwaber Mitchell J. , Venkataraman Lata , Qi Youlin , De Girolami Paola C. , Samore Matthew H. , Anderson Greg , Rasheed J. Kamile , Tenover Fred C. 
Published: April 2004

ABSTRACT

This study analyzed the enzymatic basis and molecular epidemiology of amoxicillin-clavulanate-resistant
Escherichia coli
isolated by the microbiology laboratory of a United States tertiary care hospital. From October 1998 to December 1999, all
E. coli
isolates were screened for ampicillin-sulbactam resistance. Of 283 isolates that tested resistant to ampicillin-sulbactam, 69 unique patient isolates were also resistant to amoxicillin-clavulanate by disk diffusion testing (zone diameter ≤ 13 mm). These amoxicillin-clavulanate-resistant
E. coli
isolates underwent agar dilution testing, pulsed-field gel electrophoresis, PCR analysis, and isoelectric focusing. The mean age of study patients was 52 years; 78% were female. Among the isolates, 12 were nosocomial (rate of amoxicillin-clavulanate resistance = 4.7%) and 57 were community acquired (rate of amoxicillin-clavulanate resistance = 2.8%). No predominant strain was identified. By agar dilution testing, 67 isolates were nonsusceptible (39 resistant and 28 intermediate) to amoxicillin-clavulanate and 37 were piperacillin-tazobactam resistant but only 8 were ceftazidime resistant (ceftazidime MIC ≥ 32 μg/ml). Two isolates were susceptible to amoxicillin-clavulanic acid by agar dilution, although they were resistant by disk diffusion testing. The distribution of β-lactamases was as follows: the TEM type alone was found in 52 isolates, the AmpC type was found in 4 isolates (2 identified as containing CMY-2), the TEM type and CMY-2 were found in 2 isolates, and the OXA type was found in 1 isolate. Also, there was one isolate with the TEM type and the SHV type and one with the TEM type and a second, unidentified enzyme. Among the isolates with TEM-type enzymes, two extended-spectrum β-lactamase-producing isolates were identified but two isolates with inhibitor-resistant TEM (IRT) enzymes (one with TEM-34 [IRT-6] and the other with a novel enzyme [tentatively assigned the designation TEM-122]) were more interesting.
Fungus-Elicited Metabolites from Plants as an Enriched Source for New Leishmanicidal Agents: Antifungal Phenyl-Phenalenone Phytoalexins from the Banana Plant (
Musa acuminata
) Target Mitochondria of
Leishmania donovani
Promastigotes
Authors: Luque-Ortega Juan Román , Martínez Silvia , Saugar José María , Izquierdo Laura R. , Abad Teresa , Luis Javier G. , Piñero José , Valladares Basilio , Rivas Luis 
Published: April 2004

ABSTRACT

Two antifungal phenyl-phenalenone phytoalexins isolated from the banana plant (
Musa acuminata
) elicited with the fungus
Fusarium oxysporum
, together with a methoxy derivative of one of them and two epoxide precursors of their chemical synthesis, were tested for leishmanicidal activity on
Leishmania donovani
promastigotes and
L. infantum
amastigotes. Drugs inhibited proliferation of both forms of the parasite with a 50% lethal concentration range between 10.3 and 68.7 μg/ml. Their lethal mechanism was found linked to the respiratory chain by a systematic approach, including electron microscopy, measurement of the oxygen consumption rate on digitonin-permeabilized promastigotes, and enzymatic assays on a mitochondrial enriched fraction. Whereas the whole set of compounds inhibited the activity of fumarate reductase in the mitochondrial fraction (50% effective concentration [EC
50
] between 33.3 and 78.8 μg/ml) and on purified enzyme (EC
50
= 53.3 to 115 μg/ml), inhibition for succinate dehydrogenase was only observed for the two phytoalexins with the highest leishmanicidal activity: anigorufone and its natural analogue 2-methoxy-9-phenyl-phenalen-1-one (EC
50
= 33.5 and 59.6 μg/ml, respectively). These results provided a new structural motif, phenyl-phenalenone, as a new lead for leishmanicidal activity, and support the use of plant extracts enriched in antifungal phytoalexins, synthesized under fungal challenge, as a more rational and effective strategy to screen for new plant leishmanicidal drugs.
In Vitro Activities of the β-Lactamase Inhibitors Clavulanic Acid, Sulbactam, and Tazobactam Alone or in Combination with β-Lactams against Epidemiologically Characterized Multidrug-Resistant
Acinetobacter baumannii
Strains
Authors: Higgins Paul G. , Wisplinghoff Hilmar , Stefanik Danuta , Seifert Harald 
Published: April 2004

ABSTRACT

Acinetobacter baumannii
is an important nosocomial pathogen usually in the context of serious underlying disease. Multidrug resistance in these organisms is frequent. The β-lactamase inhibitors clavulanic acid, sulbactam, and tazobactam have intrinsic activity against
Acinetobacter
strains. To evaluate their potential therapeutic usefulness, we determined the in vitro activity of ampicillin, sulbactam, ampicillin-sulbactam, cefoperazone, cefoperazone-sulbactam, piperacillin, piperacillin-sulbactam, tazobactam, piperacillin-tazobactam, amoxicillin, clavulanic acid, amoxicillin-clavulanic acid, ticarcillin, and ticarcillin-clavulanic acid against multidrug-resistant
A. baumannii
. All isolates were epidemiologically characterized by RAPD [random(ly) amplified polymorphic DNA] analysis and/or pulsed-field gel electrophoresis and represented different strain types, including sporadic strains, as well as outbreak-related strains. The MICs were determined by agar dilution on Mueller-Hinton agar (using fixed concentrations, as well as fixed ratios for β-lactamase inhibitors) and the E-test. The majority of E-test results were within two dilutions of those recorded by agar dilution, with the exception of piperacillin-tazobactam. Sulbactam was superior to clavulanic acid and tazobactam and may represent an alternative treatment option for infections due to multiresistant
A. baumannii
strains. β-Lactamase inhibitors have intrinsic activity but do not enhance activity of β-lactams against
A. baumannii
. Testing with the inhibitor added at a fixed concentration as recommended for piperacillin-tazobactam and ticarcillin-clavulanic acid by the National Committee for Clinical Laboratory Standards may falsely suggest high activity or gives uninterpretable results due to trailing. If combinations are used for testing, fixed ratios may give more useful results.
Functional Genomic Analysis of Fluconazole Susceptibility in the Pathogenic Yeast
Candida glabrata
: Roles of Calcium Signaling and Mitochondria
Authors: Kaur Rupinder , Castaño Irene , Cormack Brendan P. 
Published: April 2004

ABSTRACT

The pathogenic yeast
Candida glabrata
exhibits innate resistance to fluconazole, the most commonly used antifungal agent. By screening a library of 9,216 random insertion mutants, we identified a set of 27 genes which upon mutation, confer altered fluconazole susceptibility in
C. glabrata
. Homologues of three of these genes have been implicated in azole and/or drug resistance in
Saccharomyces cerevisiae
: two of these belong to the family of ABC transporters (
PDR5
and
PDR16
), and one is involved in retrograde signaling from mitochondria to nucleus (
RTG2
). The remaining 24 genes are involved in diverse cellular functions, including ribosomal biogenesis and mitochondrial function, activation of RNA polymerase II transcription, nuclear ubiquitin ligase function, cell wall biosynthesis, and calcium homeostasis. We characterized two sets of mutants in more detail. Strains defective in a putative plasma membrane calcium channel (Cch1-Mid1) were modestly more susceptible to fluconazole but showed a significant loss of viability upon prolonged fluconazole exposure, suggesting that calcium signaling is required for survival of azole stress in
C. glabrata
. These mutants were defective in calcium uptake in response to fluconazole exposure. The combined results suggest that, in the absence of Ca
2+
signaling, fluconazole has a fungicidal rather than a fungistatic effect on
C. glabrata
. The second set of mutants characterized in detail were defective in mitochondrial assembly and organization, and these exhibited very high levels of fluconazole resistance. Further analysis of these mutants indicated that in
C. glabrata
a mechanism exists for reversible loss of mitochondrial function that does not involve loss of mitochondrial genome and that
C. glabrata
can switch between states of mitochondrial competence and incompetence in response to fluconazole exposure.
Novel Polysulfated Galactose-Derivatized Dendrimers as Binding Antagonists of Human Immunodeficiency Virus Type 1 Infection
Authors: Kensinger Richard D. , Catalone Bradley J. , Krebs Fred C. , Wigdahl Brian , Schengrund Cara-Lynne 
Published: April 2004

ABSTRACT

Evidence indicates that galactosyl ceramide (GalCer) and its 3′-sulfated derivative, sulfatide (SGalCer), may act as alternate coreceptors for human immunodeficiency virus type 1 (HIV-1) in CD4
−
cells. Glycosphingolipids (GSLs) may also be necessary for fusion of HIV-1 and host cell membranes. Using an enzyme-linked immunosorbent assay to determine which GSL was the best ligand for both recombinant and virus-associated gp120, we found that SGalCer was the best ligand for each rgp120 and HIV-1 isolate tested. Therefore, novel multivalent glycodendrimers, which mimic the carbohydrate clustering reportedly found in lipid rafts, were synthesized based on the carbohydrate moiety of SGalCer. Here we describe the synthesis of a polysulfated galactose functionalized, fifth generation DAB dendrimer (PS Gal 64mer), containing on average two sulfate groups per galactose residue. Its ability to inhibit HIV-1 infection of cultured indicator cells was compared to that of dextran sulfate (DxS), a known, potent, binding inhibitor of HIV-1. The results indicate that the PS Gal 64mer inhibited infection by the HIV-1 isolates tested as well as DxS.
Use of Monte Carlo Simulations To Select Therapeutic Doses and Provisional Breakpoints of BAL9141
Authors: Mouton Johan W. , Schmitt-Hoffmann Anne , Shapiro Stuart , Nashed Norman , Punt Nieko C. 
Published: April 2004

ABSTRACT

BAL9141, a new antimicrobial agent belonging to the class of parenteral pyrrolidinone-3-ylidenemethyl cephalosporins, is active against most gram-positive microorganisms, including methicillin-resistant variants (methicillin-resistant
Staphylococcus aureus
[MRSA] and methicillin-resistant
Staphylococcus epidermidis
[MRSE]), as well as against penicillin-resistant pneumococci (PRP) and many gram-negative microorganisms. BAL9141 is administered as the prodrug BAL5788, which is rapidly converted to BAL9141 by plasma esterases. Pharmacokinetic (PK) data obtained in a previous multiple ascending dose study were used to fit a population PK model to using the NPEM2 program, yielding PK parameter estimates and its covariance matrix for BAL9141. These estimates and matrix were used to perform Monte Carlo simulations (MCSs) and obtain unbiased target attainment rates (TARs) for various time periods during which the concentration remains above the MIC (
T
>MIC
). Assuming a
T
>MIC
of 40%, TARs of 100% were reached with a dose of 500 mg/liter every 12 h for pathogens with MICs of 2 mg/liter and with a dose of 750 mg/liter every 12 h for pathogens with MICs of 4 mg/liter. Because MICs are ≤2 mg/liter for most strains of MRSA, MRSE, and PRP (with some strains showing an MIC of 4 mg/liter), a dosing regimen of 750 mg every 12 h is proposed for clinical studies. The corresponding provisional breakpoint is
S
(susceptible) ≤ 4 mg/liter.
Mouse Model of Cervicovaginal Toxicity and Inflammation for Preclinical Evaluation of Topical Vaginal Microbicides
Authors: Catalone Bradley J. , Kish-Catalone Tina M. , Budgeon Lynn R. , Neely Elizabeth B. , Ferguson Maelee , Krebs Fred C. , Howett Mary K. , Labib Mohamed , Rando Robert , Wigdahl Brian 
Published: April 2004

ABSTRACT
Clinical trials evaluating the efficacy of nonoxynol-9 (N-9) as a topical microbicide concluded that N-9 offers no in vivo protection against human immunodeficiency virus type 1 (HIV-1) infection, despite demonstrated in vitro inactivation of HIV-1 by N-9. These trials emphasize the need for better model systems to determine candidate microbicide effectiveness and safety in a preclinical setting. To that end, time-dependent in vitro cytotoxicity, as well as in vivo toxicity and inflammation, associated with N-9 exposure were characterized with the goal of validating a mouse model of microbicide toxicity. In vitro studies using submerged cell cultures indicated that human cervical epithelial cells were inherently more sensitive to N-9-mediated damage than human vaginal epithelial cells. These results correlated with in vivo findings obtained by using Swiss Webster mice in which intravaginal inoculation of 1% N-9 or Conceptrol gel (containing 4% N-9) resulted in selective and acute disruption of the cervical columnar epithelial cells 2 h postapplication accompanied by intense inflammatory infiltrates within the lamina propria. Although damage to the cervical epithelium was apparent out to 8 h postapplication, these tissues resembled control tissue by 24 h postapplication. In contrast, minimal damage and infiltration were associated with both short- and long-term exposure of the vaginal mucosa to either N-9 or Conceptrol. These analyses were extended to examine the relative toxicity of polyethylene hexamethylene biguanide (PEHMB), a polybiguanide compound under evaluation as a candidate topical microbicide. In similar studies, in vivo exposure to 1% PEHMB caused minimal damage and inflammation of the genital mucosa, a finding consistent with the demonstration that PEHMB was >350-fold less cytotoxic than N-9 in vitro. Collectively, these studies highlight the murine model of toxicity as a valuable tool for the preclinical assessment of toxicity and inflammation associated with exposure to candidate topical microbicides.
Noyσ Und σoia In Offb 17
Authors: Schmidt Josef 
Published: April 2004

AbstractDie apokalyptische Rätselzahl hat nicht nur die Funktion, die historische Rückschau des 13. Kapitels eindrucksvoll abzuschließen; sie ist auch im 17. Kapitel präsent. Dort repräsentiert sie die innere Mitte einer weiteren historischen Reflexion, die nun aber der künftigen Entwicklung des römischen Kaiserreiches gewidmet ist. Der Verfasser sieht die Zeit einer neuen Verfolgung am politischen Horizont heraufziehen und mahnt seine Leser zu illusionsloser Wachsamkeit. Der historische Standort des Verfassers ist die Zeit des Vespasian; sein geographischer Standort ist die Stadt Rom. Nicht nur die kryptische Geographie von Kapitel 17, sondern auch die des 11. Kapitels kann dem Areal dieser Stadt zugeordnet werden.