bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymerase chain reaction primers for microsatellite loci in the common frog Rana temporaria
Authors: Rowe Graham , Beebee Trevor J. C.
Published: April 2005

We obtained a microsatellite‐enriched genomic library from the common frog Rana temporaria using hybrid selection. From this library we isolated and characterized 10 polymorphic microsatellite loci and a single bi‐allelic marker. Primers and conditions for polymerase chain reaction (PCR) amplification of all these loci are described.
Microsatellite DNA loci in Pacific abalone Haliotis discus discus (Mollusca, Gastropoda, Haliotidae)
Authors: Sekino M. , Hara M.
Published: April 2005

Five novel microsatellite loci were isolated from Pacific abalone Haliotis discus discus, and the polymorphisms were examined to estimate genetic varaiability. The genetic variabilities varied depending on the locus: the number of alleles ranged from 3 to 10, and the observed and expected hetrozygosity ranged from 0.17 to 0.80, and 0.20 to 0.89, respectively. Two loci showed significant Hardy–Weinberg disequilibrium at the 0.01 < P < 0.05 levels. The high variabilities revealed in this study were evidently higher than that observed in allozyme loci, suggesting that these microsatellites should prove useful for various genetic investigations.
Characterization of seven microsatellite marker loci in the Malagasy civet (Fossa fossana)
Authors: Sovey K. C. , Dollar L. , Kerridge F. , Barber R. C. , Louis E. E.
Published: April 2005

We describe seven polymorphic markers that have been developed for the Malagasy civet (Fossa fossana) or Fanaloka, a nocturnal viverrid carnivore endemic to the island of Madagascar. We report primer sequences and annealing temperatures, as well as observed and expected heterozygosity values for each of these markers. The genotype frequencies for six of the markers significantly differed from Hardy–Weinberg expectations. This deviation may have been due to the presence of null alleles or to small sample size in conjunction with a high level of polymorphism.
Isolation and characterization of novel microsatellite markers from the Australian water skink Eulamprus kosciuskoi and cross‐species amplification in other members of the species‐group
Authors: Scott Ian A. W. , Hayes Christine M. , Keogh J. Scott , Morrison Suzanne F.
Published: April 2005

A panel of six samples from three Eulamprus species was used to screen 24 primer pairs developed from the Australian water skink Eulamprus kosciuskoi. We provide details of 10 microsatellite loci that exhibited the cleanest and strongest banding patterns. We also screened six of these microsatellite loci against 118 individuals from a population of E. heatwolei. These microsatellites exhibited large numbers of alleles per locus (4–19) and high heterozygosity (0.271–0.898) in this population. This suggests that they will be extremely useful for investigating mating systems and other facets of population biology in these lizards.
Isolation and characterization of polymorphic microsatellite loci in Rubus alceifolius Poir. (Rosaceae), an invasive weed in La Réunion island
Authors: Amsellem L. , Dutech C. , Billotte N.
Published: April 2005

This study characterized eight microsatellite loci of the invasive weed Rubus alceifolius, and represents the first microsatellite markers published for any Rubus species. They proved to be highly polymorphic in Asian natural populations, and could be used to compare the reproductive biology of this weed between its native range and its areas of introduction. A screening of a Vietnamese half‐sib progeny showed that sexuality occurs in this geographical range of R. alceifolius. Moreover, four of them could be potentially transferable to 14 other tropical Rubus species from the subgenera Idaeobatus and Malachobatus.
Technique for analysis of bryozoan mitochondrial DNA
Authors: Porter J. S. , Skibinski D. O. F. , Leamon J. , Hayward P. J.
Published: April 2005

The use of non‐specific mitochondrial DNA (mtDNA) primers can frequently result in the erroneous amplification of DNA from contaminating organisms or from mtDNA nuclear inserts. A reliable method for deriving species‐specific mtDNA polymerase chain reaction (PCR) primers using genomic and mtDNA enriched preparations from the same individual is described.
New polymorphic microsatellite markers for the red squirrel (Sciurus vulgaris) and their applicability to the grey squirrel (S. carolinensis)
Authors: Hale M. L. , Bevan R. , Wolff K.
Published: April 2005

The geographical range of the red squirrel (Sciurus vulgaris) in Britain has decreased substantially since the introduction of the American grey squirrel (S. carolinensis). We have developed 21 novel, polymorphic microsatellite markers for S. vulgaris to enable analysis of population genetic structure in this species. All 21 markers amplify well, and are generally polymorphic in S. carolinensis, allowing a comparison of population structure of both the introduced and native squirrel species.
Isolation and characterization of microsatellite loci in the grey mouse lemur (Microcebus murinus) and their amplification in the family Cheirogaleidae
Authors: Radespiel U. , Funk S. M. , Zimmermann E. , Bruford M. W.
Published: April 2005

Within this study seven polymorphic microsatellite primers were developed for the grey mouse lemur (Microcebus murinus) from two partial genomic libraries. One protocol was based on an initial polymerase chain reaction (PCR) with random amplified polymorphic DNA (RAPD) primers and resulted in a 5.5% enrichment, whereas the second protocol included an enrichment with three rounds of capture which yielded a 38.0% enrichment. The genotypes of 12 captive and 162 free‐living animals were determined with the newly developed primers and all seven confirmed Mendelian inheritance. All primers amplified in several species of the family Cheirogaleidae, demonstrating their general suitability for microsatellite analyses within this taxonomic group.
Nondestructive DNA extraction from sperm whale teeth and scrimshaw
Authors: Pichler F. B. , Dalebout M. L. , Baker C. S.
Published: April 2005

Sperm whales (Physeter macrocephalus), have been hunted throughout their global distribution. As a result, sizeable collections of sperm whale teeth and scrimshaw are held in museum and private collections. Access to these specimens for genetic analysis is limited due to the tendency of DNA extraction techniques to destructively sample such specimens. Here we demonstrate that small amounts of bone powder, collected by drilling inside the root cavity, can yield sufficient DNA for sequencing without adversely affecting the specimen's appearance. We anticipate that owners and curators of sperm whale teeth will be more amenable to genetic analysis using this extraction method.
A rapid and efficient method for the isolation of mitochondrial DNA from angiosperm tree species. Application to the restriction fragment length polymorphism distinction between European and American ashes
Authors: Morand M. E. , Vedel F. , Raquin C. , Frascaria‐Lacoste N.
Published: April 2005

A simplified method for the isolation of mitochondrial DNA (mtDNA) from several angiosperm tree species is described. The procedure does not require gradient ultracentrifugation or organic solvent extractions and can be performed in a single day. mtDNA was isolated from flower buds collected from adult trees just after the first pollen mitosis and purified by gravity flow through disposable columns containing an anion‐exchange resin. The method led to restrictable mtDNA from the tree species analysed. Restriction patterns enabled us to distinguish between European and American ashes.
Isolation and characterization of microsatellite loci in the Norway lobster (Nephrops norvegicus)
Authors: Streiff R. , Guillemaud T. , Alberto F. , Magalhães J. , Castro M. , Cancela M. L.
Published: April 2005

To assess the level and spatial pattern of genetic diversity of a marine crustacean species, Nephrops norvegicus, hypervariable molecular markers were obtained by screening of a partial genomic library enriched for microsatellite dinucleotide motifs. Following sequencing of the positive clones, 10 pairs of primers were designed and five of them were shown to detect polymorphic loci. These loci were checked for their variability in two natural populations, fished off the Portuguese coast. They showed a high variability for the number of alleles, and for the expected and observed heterozygosities. No significant differentiation between the two localities was observed.
Characterization of microsatellite loci in Spix's disk‐winged bats (Thyroptera tricolor)
Authors: Vonhof M. J. , Davis C. S. , Strobeck C. , Fenton M. B.
Published: April 2005

We describe the development of 11 microsatellite loci for Spix's disk‐winged bats, Thyroptera tricolor. Microsatellite markers were located using standard methodology, and tested on a population of 40 animals from Tortuguero, Costa Rica. These 11 loci had 2–18 alleles per locus, and, with the exception of two loci (TT4 and TT17), had observed and expected heterozygosities of greater than 70%. Cross‐species amplification was largely limited to another member of the same family, but several loci amplified polymorphic product in species from three other families.
A panel of microsatellites developed for meerkats (Suricata suricatta) by cross‐species amplification and species‐specific cloning
Authors: Griffin A. S. , Nürnberger B. , Pemberton J. M.
Published: April 2005

We describe the compilation of a panel of 12 polymorphic microsatellite loci suitable for inference of parentage and relatedness in the cooperatively breeding meerkat (Suricata suricatta). First, three of 70 microsatellite primer pairs characterized from other carnivores, specifically cat (Felix catta), dog (Canis familiaris) and grey seal (Halichoerus grypus) revealed polymorphic microsatellites in meerkats. Second, a further nine loci were isolated from meerkats by screening a plasmid library with a 32P‐labelled (CA)15 probe.
Characterization of microsatellite loci for Trigona carbonaria, a stingless bee endemic to Australia
Authors: Green Catherine L. , Franck Pierre , Oldroyd Benjamin P.
Published: April 2005

Microsatellite loci were isolated from Trigona carbonaria (family Apidae; tribe Meliponini), a stingless bee endemic to Australia, following the screening of a partial genomic library with several simple‐repeat oligonucleotide probes. Polymerase chain reaction (PCR) primers were designed to DNA sequence flanking a selection of trinucleotide and dinucleotide repeat sequences within positive clones. Nine of 10 microsatellite loci were found to be polymorphic amongst 20 unrelated T. carbonaria workers, with observed heterozygosity estimates ranging from 0.168 to 0.800. For many of the primers, distinct polymorphic products were also amplified when used in reactions with DNA from a selection of other bee species.
Isolation and characterization of polymorphic microsatellite markers in Schistosoma mansoni from Africa
Authors: Blair L. , Webster J. P. , Barker G. C.
Published: April 2005

The ability of microsatellite loci to reveal genetic diversity between individuals of the digenean trematode Schistosoma mansoni was investigated. A total of 10 polymorphic microsatellite markers were isolated and optimized, allowing the variability at each locus amplified within 12 individuals from three African populations to be assessed. Allelic diversity and observed heterozygosity (HO) figures ranged from 2 to 6 and 0.33 to 1.00, respectively. These results indicated high variability both between individuals and populations, highlighting the suitability of these microsatellites for future population genetic surveys.
Isolation of polymorphic microsatellite markers from the malaria vector Anopheles darlingi
Authors: Conn Jan E. , Bollback Jonathan P. , Onyabe David Y. , Robinson Tessa N. , Wilkerson Richard C. , Póvoa Marinete M.
Published: April 2005

High molecular weight DNA was extracted from the primary Neotropical malaria vector, Anopheles darlingi from Capanema, Pará, Brazil, to create a small insert genomic library, and then a phagemid library. Enriched sublibraries were constructed from the phagemid library using a microsatellite oligo primed second strand synthesis protocol. The resulting 242 760 individual clones were screened. The mean clone size of the positive clones was 302 bp. Flanking primers were designed for each suitable microsatellite sequence. Eight polymorphic loci were optimized and characterized. The allele size ranges are based on 253 samples of A. darlingi from eastern Amazonian and central Brazil.
GFP‐tagged pollen to monitor pollen flow of transgenic plants
Authors: Hudson L. C. , Chamberlain D. , Stewart C. N.
Published: April 2005

In this study, the pollen‐active LAT59 promoter from tomato was used to express a green fluorescent protein (GFP) encoding gene in Nicotiana tabacum (tobacco) pollen. This promoter is preferentially expressed in anthers and pollen. Pollen in transgenic plants segregated in a 1 : 1 Mendelian ratio, and the plants were polymerase chain reaction (PCR)‐positive. GFP‐tagged pollen was developed as a tool for tracking the movement of transgenic plant pollen in the environment. Specifically, it should be a useful tool for characterizing the spatial distribution patterns of transgenic pollen, to determine pollination mechanisms, to monitor the effects on nontarget organisms, and to monitor gene flow in field conditions.
Microsatellite markers in soil‐feeding termites (Cubitermes subarquatus, Isoptera, Termitidae, Termitinae)
Authors: Harry M. , Roose C. L. , Garnier‐Sillam E. , Solignac M.
Published: April 2005

Seven microsatellite markers were isolated from Cubitermes subarquatus belonging to the soil‐feeding termite trophic group that plays a key role in tropical rain forests. A variability study performed by using a population of C. subarquatus (n = 73) sampled in the La Lopé forest reserve (Gabon) from 42 nests revealed from 4 to 12 alleles per locus and an heterozygosity from 0.28 to 0.84. Tests for cross‐species amplification realized in the sympatric C. intercalatus and in eight other sympatric termite genera indicated a wider application of the primers isolated from Cubitermes in soil‐feeding termites.
Highly polymorphic microsatellite loci in the facultatively eusocial hover wasp, Liostenogaster flavolineata and cross‐species amplification
Authors: Sumner S. , Field J.
Published: April 2005

We describe eight polymorphic microsatellite loci for facultatively eusocial hover wasps (Hymenoptera: Stenogastrinae). Loci were isolated from a partial genomic library of Liostenogaster flavolineata DNA, enriched for GA repeats and an unenriched library of Liostenogaster vechti DNA. We present our results of cross‐species amplification in three species: L. flavolineata, L. vechti and Parischnogaster alternata.
Electrophoresis artefacts — a previously unrecognized cause of error in microsatellite analysis
Authors: Fernando Prithiviraj , Evans Ben J. , Morales Juan Carlos , Melnick Don J.
Published: April 2005

While microsatellite genotyping has found wide application in many fields, a number of causes that could lead to error in microsatellite genotyping have been previously reported. Here we report another cause of error that we term ‘Electrophoresis Artefacts’ (EA), which arise when high concentrations of polymerase chain reaction (PCR) products are electrophoresed in ABI 377 automated sequencers. We describe the phenomenon of EAs, characterize PCR and gel running conditions that cause them and suggest a simple method of overcoming this problem.
estim 1.0: a computer program to infer population parameters from one‐ and two‐locus gene identity probabilities
Authors: Vitalis R. , Couvet D.
Published: April 2005

Estimating effective population size is an important issue in population and conservation genetics. Recently, we proposed a new method to infer effective size and migration rate from one‐ and two‐locus identity probability measures. We now announce the release of a user‐friendly Microsoft® Windows program that uses this method to provide joint estimates of local effective population size and immigration rate for each subpopulation in a population genetics data set.
Polymorphic microsatellites in the African freshwater snail, Bulinus forskalii (Gastropoda, Pulmonata)
Authors: Gow J. L. , Noble L. R. , Rollinson D. , Jones C. S.
Published: April 2005

Eleven microsatellites were isolated in the freshwater snail Bulinus forskalii, intermediate host for the medically important trematode Schistosoma intercalatum. Characterization in 60 snails from three populations of B. forskalii from Cameroon revealed 4 to 18 alleles per locus. Low observed heterozygosity but higher expected heterozygosity, high FIS estimates, significant departures from Hardy–Weinberg equilibrium and genotypic linkage disequilibria all indicate that B. forskalii is a preferential selfer. High FST estimates suggest that effective dispersal is limited and genetic drift is an important determinant of genetic structure. The potential utility of the microsatellite primers in other closely related Bulinus species was explored.
Microsatellite markers in the primitive termite Mastotermes darwiniensis
Authors: Goodisman Michael A. D. , Evans Theodore A. , Ewen John G. , Crozier Ross H.
Published: April 2005

We developed 10 microsatellite loci in the primitive termite Mastotermes darwiniensis. The number of alleles per locus ranged from four to 15, and the expected heterozygosites spanned from 0.21 to 0.90, in a sample of 40 workers collected from the Northern Territory, Australia. We also determined that only two loci amplified in five other termite species. The low frequency of cross‐amplification probably resulted from the high level of phylogenetic divergence between M. darwiniensis and the other taxa. Thus, although the loci are not widely applicable, they should prove effective in elucidating the genetic structure of M. darwiniensis populations.
Molecular identification of three sympatric species of wood mice (Apodemus sylvaticus, A. flavicollis, A. alpicola) in western Europe (Muridae: Rodentia)
Authors: Michaux J. R. , Kinet S. , Filippucci M.‐G. , Libois R. , Besnard A. , Catzeflis F.
Published: April 2005

The woodmouse (Apodemus sylvaticus) and yellow‐necked fieldmouse (Apodemus flavicollis) are sympatric and even syntopic in many regions throughout their European range. Their field discrimination on the basis of external characters is a real challenge for many fields of research. The problem is even more complicated in the Alpine chain where they live sympatrically with a third similar species: A. alpicola. A rapid and simple method is proposed to discriminate the three species in processing field‐collected biopsies as well as ethanol‐preserved museum samples.
Isolation and characterization of microsatellites in the Southeast Asian river catfish Mystus nemurus
Authors: Usmani S. , Tan S. G. , Siraj S. S. , Yusoff K.
Published: April 2005

A total of 26 simple sequence repeats were identified using a random amplified polymorphic DNA (RAPD) based technique in the Southeast Asian river catfish Mystus nemurus. We report on the characterization of five polymorphic microsatellite loci in M. nemurus. The average number of alleles per locus was 3.2. These are the first microsatellite loci that have been developed for this species. These markers should prove useful as tools for managing the brood stocks and for future aquacultural development of this species.
Genome walking with consensus primers: application to the large single copy region of chloroplast DNA
Authors: Grivet D. , Heinze B. , Vendramin G. G. , Petit R. J.
Published: April 2005

Conserved chloroplast (cp) DNA primer pairs are useful in plant molecular genetics, evolution and ecology. We have designed 20 conserved cpDNA primer pairs that, in combination with 18 previously described ones, amplify overlapping fragments (mean size of 2.5 kb) spanning the large single copy (LSC) region from Eudicots. These 38 primer pairs as well as eight primer pairs flanking cpDNA microsatellites were tested on 20 plant species belonging to 13 families. At least 79% and up to 100% of the LSC (> 86 kb) can be amplified. Many primer pairs are robust and work with all species.
Microsatellites for the slugs Deroceras reticulatum and Arion intermedius
Authors: Brookes R. C. , Barker J. H. A. , Bohan D. A. , Glen D. M. , Karp A.
Published: April 2005

Microsatellites were developed for two pest slug species: self‐fertilizing Arion intermedius and outcrossing Deroceras reticulatum. Six microsatellites from each species were tested on individuals collected from within and between arable fields. The 39 individuals analysed per species had 3–9 and 7–26 alleles per microsatellite for A. intermedius and D. reticulatum, respectively. Gene diversity,

[1 − Σpi2], ranged from 0.19 to 0.75 and 0.74 to 0.95, respectively.
Polymorphic microsatellite DNA markers in black grouse (Tetrao tetrix)
Authors: Piertney Stuart B. , Höglund Jacob
Published: April 2005

Ten GATA microsatellite DNA markers were isolated and characterized from black grouse (Tetrao tetrix) using an enrichment cloning procedure. High levels of heterozygosity (mean HO = 0.74 ± 0.026), and a large number of alleles (range = 5–16) were resolved in 70 individuals, indicating these markers will be useful for examining parentage, inbreeding and population structure in black grouse. No evidence for linkage disequilibrium or the presence of null alleles was found.
Flavanols in Somatic Cell Division and Male Meiosis of Tea(Camellia sinensis)Anthers
Authors: Feucht W. , Treutter D. , Dithmar H. , Polster J.
Published: April 2005

Abstract:Young anthers excised from closed tea flower buds (Camellia sinensisL.) were stained as fresh tissues withp‐dimethylaminocinnamaldehyde reagent to localize flavanols associated with nuclei and chromosomes, apart from those flavanols stored in vacuoles. This staining reagent yields a blue colour for flavanols. In the nonsporogenic somatic cells of developing anthers, flavanols were found to be attached to chromosomes at all mitotic stages. Male meiosis started at a bud size of about 3.5 mm in diameter in pollen mother cells which displayed generally more or less pronounced blue nuclei and cytoplasm. The meiotic divisions from prophase I to telophase II were characterized by blue stained nuclei and chromosomes, but within the cytoplasm there was, if any, a random and very poor reaction for flavanols. Metaphase and telophase of meiotic divisions showed maximally condensed chromosomes staining dark blue. Early in telophase II, the cytoplasm was again stained blue; this faded at late tetrad stage. Flavanols of young mitotic and older non‐mitotic anthers were determined using high pressure liquid chromatography ‐ chemical reaction detection (HPLC‐CRD). Catechin, epicatechin, B2, and epigallocatechin were minor compounds, whereas epicatechin gallate and epigallocatechin gallate were found in higher amounts. The major flavanol compound of the anthers, epicatechin gallate, exhibited a significant affinity to histone sulphate, as shown by UV‐VIS spectroscopic titration.
Parthenocarpic Fruit Development in Tomato
Authors: Gorguet B. , van Heusden A. W. , Lindhout P.
Published: April 2005

Abstract: Parthenocarpic fruit development is a very attractive trait for growers and consumers. In tomato, three main sources of facultative parthenocarpy, pat, pat‐2, pat‐3/pat‐4, are known to have potential applications in agriculture. The parthenocarpic fruit development in these lines is triggered by a deregulation of the hormonal balance in some specific tissues. Auxins and gibberellins are considered as the key elements in parthenocarpic fruit development of those lines. An increased level of these hormones in the ovary can substitute for pollination and trigger fruit development. This has opened up genetic engineering approaches for parthenocarpy that have given promising results, both in quality and quantity of seedless fruit production.
The Inheritance of Chilling Tolerance in Tomato (Lycopersicon spp.)
Authors: Venema J. H. , Linger P. , van Heusden A. W. , van Hasselt P. R. , Brüggemann W.
Published: April 2005

Abstract: During the past 25 years, chilling tolerance of the cultivated (chilling‐sensitive) tomato Lycopersicon esculentum and its wild, chilling‐tolerant relatives L. peruvianum and L. hirsutum (and, less intensively studied, L. chilense) has been the object of several investigations. The final aim of these studies can be seen in the increase in chilling tolerance of the cultivated genotypes. In this review, we will focus on low‐temperature effects on photosynthesis and the inheritance of these traits to the offspring of various breeding attempts. While crossing L. peruvianum (♂) to L. esculentum (♀) so far has brought the most detailed insight with respect to physiological questions, for practical purposes, e.g., the readily cross ability, crossing programmes with L. hirsutum as pollen donor at present seem to be a promising way to achieve higher chilling‐tolerant genotypes of the cultivated tomato. This perspective is due to the progress that has been made with respect to the genetic basis of chilling tolerance of Lycopersicon spp. over the past five years.
Redundancy of Stomatal Control for the Circadian Photosynthetic Rhythm in Kalanchoë daigremontiana Hamet et Perrier
Authors: Wyka T. P. , Duarte H. M. , Lüttge U. E.
Published: April 2005

Abstract: In continuous light, the Crassulacean acid metabolism plant Kalanchoë daigremontiana Hamet et Perrier has a circadian rhythm of gas exchange with peaks occurring during the subjective night. The rhythm of gas exchange is coupled to a weak, reverse phased rhythm of quantum yield of photosystem II (ΦPSII). To test if the rhythm of ΦPSII persists in the absence of stomatal control, leaves were coated with a thin layer of translucent silicone grease which prevented CO2 and H2O exchange. In spite of this treatment, the rhythm of ΦPSII occurred with close to normal phase timing and with a much larger amplitude than in uncoated leaves. The mechanism underlying the ΦPSII rhythm in coated leaves can be explained by a circadian activity of phosphoenolpyruvate carboxylase (PEPC). At peaks of PEPC activity, the small amount of CO2 contained in the coated leaf could have become depleted, preventing the carboxylase activity of Rubisco and causing decreases in electron transport rates (observed as deep troughs of ΦPSII at 23‐h in LL and at ca. 24‐h intervals afterwards). Peaks of ΦPSII would be caused by a downregulation of PEPC leading to improved supply of CO2 to Rubisco. Substrate limitation of photochemistry at 23 h (trough of ΦPSII) was also suggested by the weak response of ETR in coated leaves to stepwise light enhancement. These results show that photosynthetic rhythmicity in K. daigremontiana is independent of stomatal regulation and may originate in the mesophyll.
Cytological Development and Sesquiterpene Lactone Secretion in Capitate Glandular Trichomes of Sunflower
Authors: Göpfert J. C. , Heil N. , Conrad J. , Spring O.
Published: April 2005

Abstract: The secretion of sesquiterpene lactones (STL) in capitate glandular trichomes from the anther appendages of Helianthus annuus L. (Asteraceae) was observed by light and fluorescence microscopy and HPLC analysis. Disk flowers within the sunflower capitulum showed the known ontogenetic progression from the centre to the margin. During development of the florets, the trichomes in the anther appendages secreted their metabolites into the subcuticular secretion storage space in front of the two apical cells. All stages of forming the cuticular globe, from the pre‐secretory to the post‐secretory phase, could be observed microscopically and secretory activity was simultaneously monitored. Six germacrolides and heliangolides of known structure were selected for quantitative analysis. The increase in STL content during extension of the subcuticular space was monitored by HPLC analysis. Thereby, the start and termination of STL biosynthesis was defined in relation to other developmental stages of floret ontogenesis, particularly, the pollen formation. Part of the secreted material showed autofluorescence which could be attributed to a hydroxy‐trimethoxy‐flavone, as determined by NMR and mass spectroscopy. The anther trichomes were cytologically and chemically similar to foliar glandular trichomes of sunflower and represent the multicellular capitate glandular trichome type common to many Asteraceae. The ease with which anther trichomes of H. annuus can be harvested and analyzed suggests that they can provide a valuable model system for investigation of STL and flavonoid metabolism in Asteraceae.
Structural and kinetic effects on a simple catalytic reaction: Oxygen reduction on Ni(110)
Authors: Vesselli E. , De Rogatis L. , Baraldi A. , Comelli G. , Graziani M. , Rosei R.
Published: April 2005

Oxygen hydrogenation at 100 K by gas phase atomic hydrogen on Ni(110) has been studied under ultrahigh vacuum conditions by temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS). Formation of adsorbed water and hydroxyl species was observed and characterized. The coverage of the reaction products was monitored as a function of both temperature and initial oxygen precoverage. On the contrary, when high coverage oxygen overlayers were exposed to gas phase molecular hydrogen, no hydrogenation reaction took place. The results are compared to the inverse process, exposing the hydrogen covered surface to molecular oxygen. In this case, at 100 K, simple Langmuir–Hinshelwood modeling yields an initial sticking coefficient for oxygen adsorption equal to 0.26, considerably lower than for the clean surface. Moreover, formation of hydroxyl groups is found to be twice as fast as the final hydrogenation of OH groups to water. Assuming a preexponential factor of 1013s−1, an activation barrier of 6.7kcal∕mol is obtained for OH formation, thus confirming the high hydrogenating activity of nickel with respect to other transition metals, for which higher activation energies are reported. However, oxygen is hardly removed by hydrogen on nickel: this is explained on the basis of the strong Ni–O chemical bond. The hydrogen residual coverage is well described including a contribution from the adsorption-induced H desorption process which takes place during the oxygen uptake and which is clearly visible from the TPD data.
Dynamics of deuterated polystyrene-protonated butadiene diblock copolymer micelles by neutron spin echo
Authors: Kanaya T. , Monkenbusch M. , Watanabe H. , Nagao M. , Richter D.
Published: April 2005

We report on neutron spin-echo (NSE) measurements on deuterated styrene-protonated butadiene diblock copolymer micelles in deuterated n-decane to investigate the dynamics of butadiene blocks in the corona. Before the NSE measurements, we performed small-angle neutron-scattering (SANS) measurements on the micelles to evaluate the structure to give a basis for the discussion of the dynamics. In the SANS study, we have estimated the form factor P(Q) in terms of a hard-core-shell model from the direct evaluation without curve-fitting procedure while a more flexible core-shell model with the structure factor S(Q) gives a better fit to the observed data. The observed normalized intermediate scattering function I(Q,t)∕I(Q,0) by NSE does not show the collective motions corresponding to the so-called breathing mode but rather single chain motion (Zimm modes) for both the 2 and 20 wt % micelle solutions. The Zimm decay rate Γz in the micelle solution is slow compared with that in the homopolymer solution. This slowing down is assigned to the effective high concentration in the corona. The differences in Γz between concentrated solutions and the 20% micellar solution are attributed to end-tethering effect of the corona chains on the core surface. The possible reasons why the breathing mode was not observed in the present micelle system are discussed on the basis of chain density in the corona.
Bound-state energies in argon trimers via a variational expansion: The effects from many-body corrections
Authors: Baccarelli I. , Gianturco F. A. , González-Lezana T. , Delgado-Barrio G. , Miret-Artés S. , Villarreal P.
Published: April 2005

In this paper we study the bound-state energies and geometries of Ar3 for J=0, using the distributed Gaussian functions method that provides a configurational description of the different structures contributing to these states. Atom-atom potentials are employed and three-body long-range effects are also included in the computational treatment by adding to the sum of potentials the Axilrod–Teller triple-dipole correction for the whole rotationless energy spectrum. An estimate of the total number of bound states for the Ar trimer is given. With respect to previous calculations, limited to the lower-lying states, our results show slightly larger nonadditive effects and are further able to predict the full range of the bound spectrum. Changes on the geometries of a large part of the vibrationally excited states of Ar3 when the Axilrod–Teller term is included in the molecular potential are found by the present study.
Phase behavior of the restricted primitive model of ionic fluids with association in slitlike pores. Density-functional approach
Authors: Pizio O. , Sokołowski S.
Published: April 2005

We present results of investigations of condensation of restricted primitive model of electrolyte solutions with association between oppositely charged ions confined to slitlike pores. The associative interaction leads to the formation of ionic pairs. It is accounted for by incorporating the first-order thermodynamic perturbation theory into the free energy functional. In order to elucidate the role of association, the phase diagrams are compared with those obtained by us recently [O. Pizio et al., J. Chem. Phys. 121, 11957 (2004)] for the restricted primitive model. The inclusion of the association into the theory leads to lowering the critical temperature for the fluid confined to pores with uncharged and with charged walls. We have observed that the average fraction of bonded ions is high along the coexistence envelope.
Crystalline orientation dependence of nanomechanical properties of Pb(Zr0.52Ti0.48)O3 thin films
Authors: Wang Qing-Ming , Ding Yongping , Chen Qingming , Zhao Minhua , Cheng Jinrong
Published: April 2005

It has been recognized that the control of crystalline orientation and thickness of Pb(Zr0.52Ti0.48)O3 (PZT) thin-films is very critical in the fabrication of piezoelectric thin-film devices with desirable dielectric and electromechanical properties. Here, we present our recent studies on the fabrication of PZT films with (001), (111), and random crystalline orientations onto platinized silicon substrates and the crystalline orientation dependence of the nanomechanical properties. A 1.0-μm PZT film with a strong (100) orientation is deposited by a 2–methoxyethanol- (2–MOE)-based sol–gel precursor solution, while random orientation is obtained by acetic acid-based sol–gel precursor. Rapid thermal annealing of 2–MOE sol-gel-based PZT films leads to strong (111) orientation. All PZT films show similar hysteresis behavior and large remnant polarizations; however, the nanomechanical test using AFM and nanoindentation indicates distinct values of Young’s modulus for PZT films with different orientations.
Nanoindentation response of a single micrometer-sized GaAs wall
Authors: Le Bourhis E. , Patriarche G.
Published: April 2005

Wall-patterned GaAs surfaces have been elaborated by photolithography and dry etching. The mechanical response of individual μm-sized walls was tested at different positions on the wall by nanoindentation. Overall results show that contact stiffness remains constant across the wall while total penetration drastically increases at the proximity of the free sides of the wall. Transmission electron microscopy was used to get further insight into the plastic deformation of the walls and reveals that the central-plastic zone governs the mechanical response instead of the rosette arms. The application of substrate patterning with enhanced plastic compliance is suggested in order to eliminate residual dislocations appearing in mismatched structures grown for optoelectronic devices.
Broadband difference frequency generation around phase-match singularity
Authors: Yanagawa Tsutomu , Kanbara Hirohisa , Tadanaga Osamu , Asobe Masaki , Suzuki Hiroyuki , Yumoto Junji
Published: April 2005

It is shown that a wide tunability range of greater than 500 nm can be obtained in the 2μm band in an 18 mm long periodically poled lithium niobate chip with a single quasiphase-matching grating period at a constant temperature. This letter demonstrates the difference frequency generation bandwidth. A tunable bandwidth of over 130 nm is experimentally confirmed in the 2μm region. This broad bandwidth can be realized by means of the phase-match curve distortion caused by the phase-match singularity. The wavelength conversion temperature dependence is also shown for several quasiphase-matching grating periods.
Spectral and temporal resolution of recombination from multiple excitation states in modulation-doped AlGaN∕GaN multiple quantum well heterostructures
Authors: Furis M. , Cartwright A. N. , Waldron E. L. , Schubert E. F.
Published: April 2005

Time-resolved photoluminescence measurements of carrier lifetimes in modulation-doped (100Å)AlxGa1−xN∕(100Å)GaN multiple quantum well heterostructures are reported. The photoluminescence (PL) spectrum exhibits several lines associated with recombination of carriers from multiple excited electron states to the hole ground state. The PL decay times associated with ground state recombination, e0h0, are found to be much longer than the inverse repetition rate of our system (20μs) and estimated to be 9 ms. The experimental lifetimes associated with carrier recombination from excited states vary between 4μs for the first excited state, e1h0, and 4.5 ns for the fourth excited state, e4h0. These lifetimes are in very good agreement with a self-consistent calculation of radiative recombination lifetimes which takes into account piezoelectric and spontaneous polarization. The significant differences in recombination lifetimes are the result of the large built-in electric field in the wells (0.5MV∕cm).
Manifestation of the connection between dielectric breakdown strength and contact angle saturation in electrowetting
Authors: Papathanasiou A. G. , Boudouvis A. G.
Published: April 2005

Limiting phenomena on the electrostatically assisted wetting of dielectric solids by conducting liquids are illuminated by means of computer-aided analysis. The importance of the electrostatic edge effects and their influence on the dielectric properties of the solid is raised to demonstrate that contact angle saturation sets in when the electric field strength locally exceeds the breakdown strength of the dielectric solid where the liquid sits. The proposed argument along with the computed predictions is tested against published experimental measurements showing remarkable agreement.
Atomistic modeling of shock-induced void collapse in copper
Authors: Dávila L. P. , Erhart P. , Bringa E. M. , Meyers M. A. , Lubarda V. A. , Schneider M. S. , Becker R. , Kumar M.
Published: April 2005

Nonequilibrium molecular-dynamics (MD) simulations show that shock-induced void collapse in copper occurs by emission of shear loops. These loops carry away the vacancies which comprise the void. The growth of the loops continues even after they collide and form sessile junctions, creating a hardened region around the collapsing void. The scenario seen in our simulations differs from current models that assume that prismatic loop emission is responsible for void collapse. We propose a dislocation-based model that gives excellent agreement with the stress threshold found in the MD simulations for void collapse as a function of void radius.
The p38α/β MAPK functions as a molecular switch to activate the quiescent satellite cell
Authors: Jones Nathan C. , Tyner Kristina J. , Nibarger Lisa , Stanley Heather M. , Cornelison Dawn D.W. , Fedorov Yuri V. , Olwin Bradley B.
Published: April 2005

Somatic stem cells cycle slowly or remain quiescent until required for tissue repair and maintenance. Upon muscle injury, stem cells that lie between the muscle fiber and basal lamina (satellite cells) are activated, proliferate, and eventually differentiate to repair the damaged muscle. Satellite cells in healthy muscle are quiescent, do not express MyoD family transcription factors or cell cycle regulatory genes and are insulated from the surrounding environment. Here, we report that the p38α/β family of mitogen-activated protein kinases (MAPKs) reversibly regulates the quiescent state of the skeletal muscle satellite cell. Inhibition of p38α/β MAPKs (a) promotes exit from the cell cycle, (b) prevents differentiation, and (c) insulates the cell from most external stimuli allowing the satellite cell to maintain a quiescent state. Activation of satellite cells and p38α/β MAPKs occurs concomitantly, providing further support that these MAPKs function as a molecular switch for satellite cell activation.
PKCη is required for β1γ2/β3γ2- and PKD-mediated transport to the cell surface and the organization of the Golgi apparatus
Authors: Añel Alberto Marcelo Díaz , Malhotra Vivek
Published: April 2005

Protein kinase D (PKD) binds to a pool of diacylglycerol (DAG) in the TGN and undergoes a process of activation that involves heterotrimeric GTP-binding protein subunits βγ to regulate membrane fission. This fission reaction is used to generate transport carriers at the TGN that are en route to the cell surface. We now report that PKD is activated specifically by G protein subunit β1γ2 and β3γ2 via the Golgi apparatus–associated PKCη. Compromising the kinase activity of PKCη-inhibited protein transport from TGN to the cell surface. Expression of constitutively activated PKCη caused Golgi fragmentation, which was inhibited by a kinase inactive form of PKD. Our findings reveal that βγ, PKCη, and PKD act in series to generate transport carriers from the TGN and their overactivation results in complete vesiculation of the Golgi apparatus.
Sensitivity of laser light depolarization analysis for detection of malaria in blood samples
Authors: Padial Manuel Martínez , Subirats Mercedes , Puente Sabino , Lago Mar , Crespo Santiago , Palacios Gonzalo , Baquero Margarita
Published: April 2005

Automated light depolarization analysis could be a useful tool for diagnosing malarial infections. This work discusses the results of a diagnostic efficacy study on 411 samples from patients with suspected malaria infection performed with a Cell-Dyn 4000 analyser. Light dispersed at 90° and depolarized can be used for identifying and counting eosinophils. However, other cell populations with depolarizing capacity occur in malarial samples; these result from leukocytes ingesting haemozoin that is derived from the degradation of the haem group of haemoglobin performed by the parasite. A sensitivity of 72 % and specificity of 98 % were recorded, with positive and negative predictive values of 78 % and 97 %, respectively. Although the sensitivity level of the automated light depolarization analysis is not adequate to replace the existing methods for the diagnosis of parasitic diseases, it could alert clinicians to unsuspected infections by parasites, particularly those from the genus Plasmodium.
A novel porA-based real-time PCR for detection of meningococcal carriage
Authors: Jordens J Zoe , Heckels John E
Published: April 2005

Real-time PCR based on the capsule transfer gene (ctrA) is a significant aid in the diagnosis of meningococcal infection but fails to detect a high proportion (60 %) of non-groupable strains associated with nasopharyngeal carriage. This study aimed to design a novel real-time (TaqMan) PCR that would detect more strains of meningococci and be suitable for large-scale carriage studies. Primer and probe sequences were based on the meningococcal porA gene and designed specifically to exclude the highly related porA pseudogene in Neisseria gonorrhoeae. The specificity of the assay was confirmed by testing strains of N. gonorrhoeae known to contain the porA pseudogene together with commensal strains of Neisseria lactamica and Neisseria sicca. None of these was detected in the assay. Neisseria meningitidis strains representing a wide range of serogroups together with non-groupable strains isolated from the nasopharynx were tested by ctrA assay and the novel porA-based TaqMan PCR. All carriage strains were detected by the porA-based assay including four that gave weak or no reaction with the ctrA assay. Comparison of ctrA and porA assays on 71 throat swabs obtained from university students showed that the porA assay detected meningococcal DNA in all samples that were ctrA positive plus three that were ctrA negative but culture positive. This novel porA-based TaqMan assay provides a highly specific method for detecting meningococcal DNA that is more sensitive than the ctrA assay for detecting meningococcal carriage and is particularly suitable for carriage studies where non-groupable strains and other Neisseria are present.
Activity of Bulgarian propolis against 94 Helicobacter pylori strains in vitro by agar-well diffusion, agar dilution and disc diffusion methods
Authors: Boyanova Lyudmila , Gergova Galina , Nikolov Rossen , Derejian Sirigan , Lazarova Elena , Katsarov Nikolai , Mitov Ivan , Krastev Zacharii
Published: April 2005

Propolis exhibits antimicrobial, anti-inflammatory and other biological effects. The aim of this study was to evaluate the activity of 30 % ethanolic extract of Bulgarian propolis against 94 Helicobacter pylori strains by three methods. By the agar-well diffusion method, only 13.8 % of the strains exhibited no inhibition by 30 μl propolis extract (containing 9 mg propolis) and all isolates were inhibited to some extent by 90 μl of the extract (27 mg propolis) per well. The mean diameters of growth inhibition by 30, 60 or 90 μl propolis extract or 30 μl 96 % ethanol per well were 16.8, 19.2, 27.5 and 8.3 mm, respectively. The propolis extract was more active than the ethanol (P < 0.001). With 90 μl propolis extract per well, 69.4 % of the strains exhibited large diameters of growth inhibition (⩾20 mm) versus 26.6 % with 30 μl per well (P < 0.001). With moist propolis discs, inhibition was detected in more strains (92.1 %) than with dried discs (78.2 %, P < 0.05), with mean inhibitory diameters of 18.7 and 13.8 mm, respectively. By the agar dilution method, 100 and 300 μg propolis ml−1 inhibited the growth of 57.1 % and 76.2 %, respectively, of the 21 strains tested. In conclusion, Bulgarian propolis had a strong and dose-dependent activity against most of the H. pylori strains tested. Although the effect of propolis on H. pylori in vitro is promising, further microbiological, pharmacological and clinical trials are required.
Comparison of serotyping, pulsed field gel electrophoresis and amplified fragment length polymorphism for typing of Streptococcus pneumoniae
Authors: Shaaly Aishath , Tellevik Marit Gjerde , Langeland Nina , Høiby E Arne , Jureen Roland
Published: April 2005

The aim of the present study was to compare serotyping, PFGE and AFLP for typing of Streptococcus pneumoniae with regard to discriminatory power, typeability and typing system concordance. Thirty-four isolates from cerobrospinal fluid and 34 time-matched blood culture isolates collected from in-patients at two hospitals in western Norway during the period from January 1994 to May 2002 were included in the study. The discriminatory powers of serotyping, PFGE and AFLP were 0.93, 0.99 and 0.95, respectively. The typeabilities for serotyping, PFGE and AFLP were 1, 1 and 0.99, respectively. A good concordance was shown between all the typing methods. Serotyping would most probably have a higher discriminatory power if further subtyping had been performed. PFGE was more discriminatory than AFLP, and AFLP grouped more-distantly related isolates together. The two typing methods thus provided different information, and therefore both could be useful adjuncts to serotyping for the characterization of S. pneumoniae.