bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Interactions between the Specialist HerbivoreManduca sexta (Lepidoptera, Sphingidae) and Its Natural Host Nicotiana attenuata. VI. Microarray Analysis Reveals That Most Herbivore-Specific Transcriptional Changes Are Mediated by Fatty Acid-Amino Acid Conjugates,
Authors: Halitschke Rayko , Gase Klaus , Hui Dequan , Schmidt Dominik D. , Baldwin Ian T. 
Published: April 2003

Abstract
Evidence is accumulating that insect-specific plant responses are mediated by constituents in the oral secretions and regurgitants (R) of herbivores, however the relative importance of the different potentially active constituents remains unclear. Fatty acid-amino acid conjugates (FACs) are found in the R of many insect herbivores and have been shown to be necessary and sufficient to elicit a set of herbivore-specific responses when the native tobacco plantNicotiana attenuata is attacked by the tobacco hornworm,Manduca sexta. Attack by this specialist herbivore results in a large transcriptional reorganization in N. attenuata, and 161 genes have been cloned from previous cDNA differential display-polymerase chain reaction and subtractive hybridization with magnetic beads analysis. cDNAs of these genes, in addition to those of 73 new R-responsive genes identified by cDNA-amplified fragment-length polymorphism display of R-elicited plants, were spotted on polyepoxide coated glass slides to create microarrays highly enriched in Manduca spp.- and R-induced genes. With these microarrays, we compare transcriptional responses in N. attenuata treated with R from the two most damaging lepidopteran herbivores of this plant in nature, M. sexta and Manduca quinquemaculata, which have very similar FAC compositions in their R, and with the two most abundant FACs in Manduca spp. R. More than 68% of the genes up- and down-regulated by M. sexta R were similarly regulated byM. quinquemaculata R. A majority of genes up-regulated (64%) and down-regulated (49%) by M. sexta R were similarly regulated by treatment with the two FACs. In contrast, few genes showed similar transcriptional changes after H2O2- and R-treatment. These results demonstrate that the two most abundant FACs in Manduca spp. R can account for the majority ofManduca spp.-induced alterations of the wound response of N. attenuata.
Accumulation of Ferrous Iron in Chlamydomonas reinhardtii. Influence of CO2 and Anaerobic Induction of the Reversible Hydrogenase
Authors: Semin Boris K. , Davletshina Lira N. , Novakova Alla A. , Kiseleva Tat'yana Y. , Lanchinskaya Victoriya Y. , Aleksandrov Anatolii Y. , Seifulina Nora , Ivanov Il'ya I. , Seibert Michael , Rubin Andrei B. 
Published: April 2003

Abstract
The green alga, Chlamydomonas reinhardtii, can photoproduce molecular H2 via ferredoxin and the reversible [Fe]hydrogenase enzyme under anaerobic conditions. Recently, a novel approach for sustained H2 gas photoproduction was discovered in cell cultures subjected to S-deprived conditions (A. Melis, L. Zhang, M. Forestier, M.L. Ghirardi, M. Seibert [2000] Plant Physiol 122: 127–135). The close relationship between S and Fe in the H2-production process is of interest because Fe-S clusters are constituents of both ferredoxin and hydrogenase. In this study, we used Mössbauer spectroscopy to examine both the uptake of Fe by the alga at different CO2concentrations during growth and the influence of anaerobiosis on the accumulation of Fe. Algal cells grown in media with57Fe(III) at elevated (3%, v/v) CO2concentration exhibit elevated levels of Fe and have two comparable pools of the ion: (a) Fe(III) with Mössbauer parameters of quadrupole splitting = 0.65 mm s−1 and isomeric shift = 0.46 mm s−1 and (b) Fe(II) with quadrupole splitting = 3.1 mm s−1 and isomeric shift = 1.36 mm s−1. Disruption of the cells and use of the specific Fe chelator, bathophenanthroline, have demonstrated that the Fe(II) pool is located inside the cell. The amount of Fe(III) in the cells increases with the age of the algal culture, whereas the amount of Fe(II) remains constant on a chlorophyll basis. Growing the algae under atmospheric CO2 (limiting) conditions, compared with 3% (v/v) CO2, resulted in a decrease in the intracellular Fe(II) content by a factor of 3. IncubatingC. reinhardtii cells, grown at atmospheric CO2 for 3 h in the dark under anaerobic conditions, not only induced hydrogenase activity but also increased the Fe(II) content in the cells up to the saturation level observed in cells grown aerobically at high CO2. This result is novel and suggests a correlation between the amount of Fe(II) cations stored in the cells, the CO2 concentration, and anaerobiosis. A comparison of Fe-uptake results with a cyanobacterium, yeast, and algae suggests that the intracellular Fe(II) pool in C.reinhardtii may reside in the cell vacuole.
New Insight into Phaeodactylum tricornutum Fatty Acid Metabolism. Cloning and Functional Characterization of Plastidial and Microsomal Δ12-Fatty Acid Desaturases,
Authors: Domergue Frédéric , Spiekermann Patricia , Lerchl Jens , Beckmann Christoph , Kilian Oliver , Kroth Peter G. , Boland Wilhem , Zähringer Ulrich , Heinz Ernst 
Published: April 2003

Abstract
In contrast to 16:3 plants like rapeseed (Brassica napus), which contain α-linolenic acid (18:3Δ 9,12,15) and hexadecatrienoic acid (16:3Δ 7,10,13) as major polyunsaturated fatty acids in leaves, the silica-less diatom Phaeodactylum tricornutum contains eicosapentaenoic acid (EPA; 20:5Δ 5,8,11,14,17) and a different isomer of hexadecatrienoic acid (16:3Δ 6,9,12). In this report, we describe the characterization of two cDNAs having sequence homology to Δ12-fatty acid desaturases from higher plants. These cDNAs were shown to code for a microsomal and a plastidial Δ12-desaturase (PtFAD2 and PtFAD6, respectively) by heterologous expression in yeast (Saccharomyces cerevisiae) andSynechococcus, respectively. Using these systems in the presence of exogenously supplied fatty acids, the substrate specificities of the two desaturases were determined and compared with those of the corresponding rapeseed enzymes (BnFAD2 and BnFAD6). The microsomal desaturases were similarly specific for oleic acid (18:1Δ 9), suggesting that PtFAD2 is involved in the biosynthesis of EPA. In contrast, the plastidial desaturase from the higher plant and the diatom clearly differed. Although the rapeseed plastidial desaturase showed high activity toward the ω9-fatty acids 18:1Δ 9 and 16:1Δ 7, in line with the fatty acid composition of rapeseed leaves, the enzyme of P. tricornutum was highly specific for 16:1Δ 9. Our results indicate that in contrast to EPA, which is synthesized in the microsomes, the hexadecatrienoic acid isomer found in P. tricornutum(16:3Δ 6,9,12) is of plastidial origin.
Volatile Ester Formation in Roses. Identification of an Acetyl-Coenzyme A. Geraniol/Citronellol Acetyltransferase in Developing Rose Petals
Authors: Shalit Moshe , Guterman Inna , Volpin Hanne , Bar Einat , Tamari Tal , Menda Naama , Adam Zach , Zamir Dani , Vainstein Alexander , Weiss David , Pichersky Eran , Lewinsohn Efraim 
Published: April 2003

Abstract
The aroma of roses (Rosa hybrida) is due to more than 400 volatile compounds including terpenes, esters, and phenolic derivatives. 2-Phenylethyl acetate, cis-3-hexenyl acetate, geranyl acetate, and citronellyl acetate were identified as the main volatile esters emitted by the flowers of the scented rose var. “Fragrant Cloud.” Cell-free extracts of petals acetylated several alcohols, utilizing acetyl-coenzyme A, to produce the corresponding acetate esters. Screening for genes similar to known plant alcohol acetyltransferases in a rose expressed sequence tag database yielded a cDNA (RhAAT1) encoding a protein with high similarity to several members of the BAHD family of acyltransferases. This cDNA was functionally expressed inEscherichia coli, and its gene product displayed acetyl-coenzyme A:geraniol acetyltransferase enzymatic activity in vitro. The RhAAT1 protein accepted other alcohols such as citronellol and 1-octanol as substrates, but 2-phenylethyl alcohol andcis-3-hexen-1-ol were poor substrates, suggesting that additional acetyltransferases are present in rose petals. The RhAAT1 protein is a polypeptide of 458 amino acids, with a calculated molecular mass of 51.8 kD, pI of 5.45, and is active as a monomer. TheRhAAT1 gene was expressed exclusively in floral tissue with maximum transcript levels occurring at stage 4 of flower development, where scent emission is at its peak.
Reduction of Cholesterol and Glycoalkaloid Levels in Transgenic Potato Plants by Overexpression of a Type 1 Sterol Methyltransferase cDNA
Authors: Arnqvist Lisa , Dutta Paresh C. , Jonsson Lisbeth , Sitbon Folke 
Published: April 2003

Abstract
Transgenic potato (Solanum tuberosum cv Désirée) plants overexpressing a soybean (Glycine max) type 1 sterol methyltransferase (GmSMT1) cDNA were generated and used to study sterol biosynthesis in relation to the production of toxic glycoalkaloids. Transgenic plants displayed an increased total sterol level in both leaves and tubers, mainly due to increased levels of the 24-ethyl sterols isofucosterol and sitosterol. The higher total sterol level was due to increases in both free and esterified sterols. However, the level of free cholesterol, a nonalkylated sterol, was decreased. Associated with this was a decreased glycoalkaloid level in leaves and tubers, down to 41% and 63% of wild-type levels, respectively. The results show that glycoalkaloid biosynthesis can be down-regulated in transgenic potato plants by reducing the content of free nonalkylated sterols, and they support the view of cholesterol as a precursor in glycoalkaloid biosynthesis.
The Gluconeogenic Enzyme Phosphoenolpyruvate Carboxykinase in Arabidopsis Is Essential for Seedling Establishment
Authors: Rylott Elizabeth L. , Gilday Alison D. , Graham Ian A. 
Published: April 2003

Abstract
Phosphoenolpyruvate carboxykinase (PEPCK) catalyzes the conversion of oxaloacetate to phosphoenolpyruvate in the gluconeogenic production of sugars from storage oil in germinating oilseeds. Here, we present the results of analysis on PEPCK antisense Arabidopsis plants with a range of enzyme activities from 20% to 80% of wild-type levels. There is a direct correlation between enzyme activity and seedling establishment during early post-germinative growth, thus demonstrating the absolute requirement of PEPCK and gluconeogenesis in this process. Soluble sugar levels in the 35S-PCK1 antisense seedlings are reduced and seedling establishment can be rescued with an exogenous supply of sucrose. We observed an increase in the respiration of acetyl coenzyme A units released from fatty acid β-oxidation and a corresponding decrease in the production of sugars with decreasing enzyme activity in 2-d-old antisense seedlings. The 35S-PCK1 antisense lines have a more extreme phenotype when compared with Arabidopsis mutants disrupted in the glyoxylate cycle. We conclude that the 35S-PCK1antisense seedlings are compromised in the ability to use both storage lipid and storage protein through gluconeogenesis to produce soluble sugars.
Drought-Induced Changes in the Redox State of α-Tocopherol, Ascorbate, and the Diterpene Carnosic Acid in Chloroplasts of Labiatae Species Differing in Carnosic Acid Contents
Authors: Munné-Bosch Sergi , Alegre Leonor 
Published: April 2003

Abstract
To assess antioxidative protection by carnosic acid (CA) in combination with that of other low-molecular weight (M r) antioxidants (α-tocopherol [α-T] and ascorbate [Asc]) in chloroplasts, we measured endogenous concentrations of these antioxidants, their redox states, and other indicators of oxidative stress in chloroplasts of three Labiatae species, differing in their CA contents, exposed to drought stress in the field. Damage to the photosynthetic apparatus was observed neither in CA-containing species (rosemary [Rosmarinus officinalis]) and sage [Salvia officinalis]) nor in CA-free species (lemon balm [Melissa officinalis]) at relative leaf water contents between 86% and 58%, as indicated by constant maximum efficiency of photosystem II photochemistry ratios and malondialdehyde levels in chloroplasts. The three species showed significant increases in α-T, a shift of the redox state of α-T toward its reduced state, and increased Asc levels in chloroplasts under stress. Lemon balm showed the highest increases in α-T and Asc in chloroplasts under stress, which might compensate for the lack of CA. Besides, whereas in rosemary and sage, the redox state of CA was shifted toward its oxidized state and the redox state of Asc was kept constant, lemon balm displayed a shift of the redox state of Asc toward its oxidized state under stress. In vitro experiments showed that both CA and Asc protect α-T and photosynthetic membranes against oxidative damage. These results are consistent with the contention that CA, in combination with other low-M r antioxidants, helps to prevent oxidative damage in chloroplasts of water-stressed plants, and they show functional interdependence among different low-M r antioxidants in chloroplasts.
Potential Impact of Increased Use of Biocides in Consumer Products on Prevalence of Antibiotic Resistance
Authors: Gilbert Peter , McBain Andrew J. 
Published: April 2003

SUMMARYThere has recently been much controversy surrounding the increased use of antibacterial substances in a wide range of consumer products and the possibility that, as with antibiotics, indiscriminate use of biocides might contribute to the overall pattern of susceptibility in the general environment and in the clinic. Such speculation, based on the isolation of resistant mutants from in vitro monoculture experiments, is not reflected by an emergence of biocide-resistant strains in vivo. This review provides a broad coverage of the biocide and resistance literature and evaluates the potential risks, perceived from such laboratory monoculture experiments, against evidence gathered over 50 years of field studies. An explanation for the continued effectiveness of broad-spectrum biocidal agents against the decline in efficacy of therapeutic agents is provided based on the fitness costs of resistance and the ubiquity of naturally occurring substances that possess antibacterial effect. While we conclude from this review of the literature that the incorporation of antibacterial agents into a widening sphere of personal products has had little or no impact on the patterns of microbial susceptibility observed in the environment, the associated risks remain finite. The use of such products should therefore be associated with a clear demonstration of added value either to consumer health or to the product life. Hygienic products should therefore be targeted to applications for which the risks have been established.
Parainfluenza Viruses
Authors: Henrickson Kelly J. 
Published: April 2003

SUMMARYHuman parainfluenza viruses (HPIV) were first discovered in the late 1950s. Over the last decade, considerable knowledge about their molecular structure and function has been accumulated. This has led to significant changes in both the nomenclature and taxonomic relationships of these viruses. HPIV is genetically and antigenically divided into types 1 to 4. Further major subtypes of HPIV-4 (A and B) and subgroups/genotypes of HPIV-1 and HPIV-3 have been described. HPIV-1 to HPIV-3 are major causes of lower respiratory infections in infants, young children, the immunocompromised, the chronically ill, and the elderly. Each subtype can cause somewhat unique clinical diseases in different hosts. HPIV are enveloped and of medium size (150 to 250 nm), and their RNA genome is in the negative sense. These viruses belong to the Paramyxoviridae family, one of the largest and most rapidly growing groups of viruses causing significant human and veterinary disease. HPIV are closely related to recently discovered megamyxoviruses (Hendra and Nipah viruses) and metapneumovirus.
Pneumococcal Vaccination and Revaccination of Older Adults
Authors: Artz Andrew S. , Ershler William B. , Longo Dan L. 
Published: April 2003

SUMMARYAs individuals advance in age, the risk of infection, bacteremia, and mortality caused by Streptococcus pneumoniae rises. Retrospective data demonstrate that the licensed penumococcal polysaccharide vaccine (PPV) is effective in older persons in reducing serotype-specific invasive disease. PPV demonstrates good immunogenicity in older adults, generally comparable to that in younger subjects, although certain cohorts respond less well. The response to PPV is T cell independent, however, and does not elicit immunologic memory. The duration of the anti-capsular polysaccharide antibody response appears to wane as early as 3 years after vaccination. In older persons, revaccination induces an antibody response, although it may not be as strong as that from the initial vaccine. While revaccination of older adults has been recommended, clinical efficacy has not yet been proven. Measures of antibody function may be at least as important in determining protection as are quantitative antibody levels. Additional studies of immunogenicity, particularly regarding revaccination, will facilitate the design of an optimal pneumococcal vaccination policy. Research into conjugate- and protein-based pneumococcal vaccines, which elicit T-cell-dependent responses and induce immunologic memory, is needed in older persons. In the meantime, administering to PPV to recommended groups should be a public health priority.
Impact of Genotypic Studies on Mycobacterial Taxonomy: the New Mycobacteria of the 1990s
Authors: Tortoli Enrico 
Published: April 2003

SUMMARYThe advancement of genetic techniques has greatly boosted taxonomic studies in recent years. Within the genus Mycobacterium, 42 new species have been detected since 1990, most of which were grown from clinical samples. Along with species for which relatively large numbers of strains have been reported, some of the new species of mycobacteria have been detected rarely or even only once. From the phenotypic point of view, among the new taxa, chromogens exceed nonchromogens while the numbers of slowly and rapidly growing species are equivalent. Whereas conventional identification tests were usually inconclusive, an important role was played by lipid analyses and in particular by high-performance liquid chromatography. Genotypic investigations based on sequencing of 16S rRNA gene have certainly made the most important contribution. The investigation of genetic relatedness led to the redistribution of the species previously included in the classically known categories of slow and rapid growers into new groupings. Within slow growers, the intermediate branch related to Mycobacterium simiae and the cluster of organisms related to Mycobacterium terrae have been differentiated; among rapid growers, the group of thermotolerant mycobacteria has emerged. The majority of species are resistant to isoniazid and, to a lesser extent, to rifampin. Many of the new species of mycobacteria are potentially pathogenic, and there are numerous reports of their involvement in diseases. Apart from disseminated and localized diseases in immunocompromised patients, the most frequent infections in immunocompetent people involve the lungs, skin, and, in children, cervical lymph nodes. The awareness of such new mycobacteria, far from being a merely speculative exercise, is therefore important for clinicians and microbiologists.
Inhibition of Respiratory Syncytial Virus Fusion by the Small Molecule VP-14637 via Specific Interactions with F Protein
Authors: Douglas Janet L. , Panis Marites L. , Ho Edmund , Lin Kuei-Ying , Krawczyk Steve H. , Grant Deborah M. , Cai Ruby , Swaminathan Swami , Cihlar Tomas 
Published: April 2003

ABSTRACT
Human respiratory syncytial virus (RSV) is a major cause of respiratory tract infections worldwide. Several novel small-molecule inhibitors of RSV have been identified, but they are still in preclinical or early clinical evaluation. One such inhibitor is a recently discovered triphenol-based molecule, VP-14637 (ViroPharma). Initial experiments suggested that VP-14637 acted early and might be an RSV fusion inhibitor. Here we present studies demonstrating that VP-14637 does not block RSV adsorption but inhibits RSV-induced cell-cell fusion and binds specifically to RSV-infected cells with an affinity corresponding to its inhibitory potency. VP-14637 is capable of specifically interacting with the RSV fusion protein expressed by a T7 vaccinia virus system. RSV variants resistant to VP-14637 were selected; they had mutations localized to two distinct regions of the RSV F protein, heptad repeat 2 (HR2) and the intervening domain between heptad repeat 1 (HR1) and HR2. No mutations arose in HR1, suggesting a mechanism other than direct disruption of the heptad repeat interaction. The F proteins containing the resistance mutations exhibited greatly reduced binding of VP-14637. Despite segregating with the membrane fraction following incubation with intact RSV-infected cells, the compound did not bind to membranes isolated from RSV-infected cells. In addition, binding of VP-14637 was substantially compromised at temperatures of ≤22°C. Therefore, we propose that VP-14637 inhibits RSV through a novel mechanism involving an interaction between the compound and a transient conformation of the RSV F protein.
Poliovirus
cre
(2C)-Dependent Synthesis of VPgpUpU Is Required for Positive- but Not Negative-Strand RNA Synthesis
Authors: Morasco B. Joan , Sharma Nidhi , Parilla Jessica , Flanegan James B. 
Published: April 2003

ABSTRACT

The
cre
(2C) hairpin is a
cis
-acting replication element in poliovirus RNA and serves as a template for the synthesis of VPgpUpU. We investigated the role of the
cre
(2C) hairpin on VPgpUpU synthesis and viral RNA replication in preinitiation RNA replication complexes isolated from HeLa S10 translation-RNA replication reactions. c
re
(2C) hairpin mutations that block VPgpUpU synthesis in reconstituted assays with purified VPg and poliovirus polymerase were also found to completely inhibit VPgpUpU synthesis in preinitiation replication complexes. Surprisingly, blocking VPgpUpU synthesis by mutating the
cre
(2C) hairpin had no significant effect on negative-strand synthesis but completely inhibited positive-strand synthesis. Negative-strand RNA synthesized in these reactions immunoprecipitated with anti-VPg antibody and demonstrated that it was covalently linked to VPg. This indicated that VPg was used to initiate negative-strand RNA synthesis, although the
cre
(2C)-dependent synthesis of VPgpUpU was inhibited. Based on these results, we concluded that the
cre
(2C)-dependent synthesis of VPgpUpU was required for positive- but not negative-strand RNA synthesis. These findings suggest a replication model in which negative-strand synthesis initiates with VPg uridylylated in the 3′ poly(A) tail in virion RNA and positive-strand synthesis initiates with VPgpUpU synthesized on the
cre
(2C) hairpin. The pool of excess VPgpUpU synthesized on the
cre
(2C) hairpin should support high levels of positive-strand synthesis and thereby promote the asymmetric replication of poliovirus RNA.