bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel bacteria degrading N-acylhomoserine lactones and their use as quenchers of quorum-sensing-regulated functions of plant-pathogenic bacteria
Authors: Uroz Stéphane , D'Angelo-Picard Cathy , Carlier Aurélien , Elasri Miena , Sicot Carine , Petit Annik , Oger Phil , Faure Denis , Dessaux Yves
Published: August 2003

Bacteria degrading the quorum-sensing (QS) signal molecule N-hexanoylhomoserine lactone were isolated from a tobacco rhizosphere. Twenty-five isolates degrading this homoserine lactone fell into six groups according to their genomic REP-PCR and rrs PCR-RFLP profiles. Representative strains from each group were identified as members of the genera Pseudomonas, Comamonas, Variovorax and Rhodococcus. All these isolates degraded N-acylhomoserine lactones other than the hexanoic acid derivative, albeit with different specificity and kinetics. One of these isolates, Rhodococcus erythropolis strain W2, was used to quench QS-regulated functions of other microbes. In vitro, W2 strongly interfered with violacein production by Chromobacterium violaceum, and transfer of pathogenicity in Agrobacterium tumefaciens. In planta, R. erythropolis W2 markedly reduced the pathogenicity of Pectobacterium carotovorum subsp. carotovorum in potato tubers. These series of results reveal the diversity of the QS-interfering bacteria in the rhizosphere and demonstrate the validity of targeting QS signal molecules to control pathogens with natural bacterial isolates.
Cholic acid accumulation and its diminution by short-chain fatty acids in bifidobacteria
Authors: Kurdi Peter , Tanaka Hiroshi , van Veen Hendrik W. , Asano Kozo , Tomita Fusao , Yokota Atsushi
Published: August 2003

Cholic acid (CA) transport was investigated in nine intestinalBifidobacteriumstrains. Upon energization with glucose, all of the bifidobacteria accumulated CA. The driving force behind CA accumulation was found to be the transmembrane proton gradient (ΔpH, alkaline interior). The levels of accumulated CA generally coincided with the theoretical values, which were calculated by the Henderson–Hasselbalch equation using the measured internal pH values of the bifidobacteria, and a pKavalue of 6·4 for CA. These results suggest that the mechanism of CA accumulation is based on the diffusion of a hydrophobic weak acid across the bacterial cell membrane, and its dissociation according to the ΔpH value. A mixture of short-chain fatty acids (acetate, propionate and butyrate) at the appropriate colonic concentration (117 mM in total) reduced CA accumulation inBifidobacterium breveJCM 1192T. These short-chain fatty acids, which are weak acids, reduced the ΔpH, thereby decreasing CA accumulation in a dose-dependent manner. The bifidobacteria did not alter or modify the CA molecule. The probiotic potential of CA accumulationin vivois discussed in relation to human bile acid metabolism.
Liquid dispensing encapsulation in semiconductor packaging
Authors: Yang Liyu , King Carl K. , Bernstein Joseph B.
Published: August 2003

Liquid encapsulation techniques have been used extensively in advanced semiconductor packaging, including applications of underfilling, cavity‐filling, and glob top encapsulation. Because of the advanced encapsulation materials and the automatic liquid dispensing equipment involved, it is very important to understand the encapsulation material characteristics, equipment characteristics, encapsulation process development techniques in order to achieve the encapsulation quality and reliability. In this paper, the authors will examine the various considerations in liquid encapsulation applications and address the concerns on material characterization, automatic liquid dispensing equipment/process characterization and the encapsulation quality and reliability. The discussions will be helpful for future material and process development of semiconductor packages.
Environmental Information Disclosure Programs: They Work, but Why?
Authors: Stephan Mark
Published: August 2003

Objective. Despite the rich discussions about the role of information disclosure programs in environmental policy, our theoretical understanding of how and why information disclosure programs work lacks a clear framework. This article begins to fill that void by laying out some fundamental theories and concepts that underlie the empirical work on the subject. Methods. Basic theories arising from our knowledge of economics, psychology, and politics are compared. Previous research is analyzed with these theories in mind. Results. Research results confirm the plausibility of each of these theories, though the most compelling evidence so far suggests that shock and shame are key motivating factors for improved environmental performance by industry. Conclusions. The argument is made that our theoretical foundations must be understood better if we are to make sense of the empirical work on the subject. Policy implications are addressed.
Does Privatization Protect Natural Resources? Property Rights and Forests in Guatemala
Authors: Gibson Clark C. , Lehoucq Fabrice E. , Williams John T.
Published: August 2003

Objectives. Property rights are central to debates about natural resource policy. Governments traditionally have been seen as the appropriate custodians of natural resources for their citizens. More recently, many argue the privatization of property rights will ensure that users have incentives to manage their resources well. Common property, to the extent it is discussed at all, is seen as leading to the tragedy of the commons. We evaluate these claims by assessing property rights and forest conditions in two private and three communal forests in Guatemala. Methods. Data on biological and social phenomena from five forests (151 plots) and their associated communities were collected using the International Forestry Resources and Institutions Research Program protocols. Ordinary least squares regression was used to analyze four models. We examined t‐scores for differences in coefficients for the different models. Results. The models demonstrate that de jure property rights are not a powerful predictor of variations among the sampled forests. Conclusions. We argue that de facto institutions and their enforcement are much more important than de jure property rights to forest management. Communities holding a forest in common can, under certain circumstances, create institutions to manage their resources as successfully as—or more successfully than—private owners.
An Examination of Accidental‐Release Scenarios from Chemical‐Processing Sites: The Relation of Race to Distance
Authors: Pine John C. , Marx Brian D. , Lakshmanan Aruna
Published: August 2003

Objective. This study is intended to enhance the discussion of environmental equity by offering a methodology that is based on chemical‐specific risk zones that reflect inventories of chemical facilities, risk dispersion modeling, local weather conditions, and the unique chemical processes of each site. The central question concerns whether the racial makeup of a community near a chemical‐processing site is characteristic of the city, county, or community as a whole. In essence, does the racial makeup of a community vary by distance from a chemical‐processing facility? Methods. A comparison of the racial makeup of the community was examined for 13 chemical‐processing sites submitting off‐site consequence data under the Environmental Protection Agency Risk Management Plan, by clusters of the sites, and for all sites in the community. Instead of relative ratios, we look at odds ratios. The odds ratio compares the odds of being African American to the odds of being non‐African American at two given distance classes. In this way we may make inferences about how much higher (or lower) are the odds of an African American (relative to a non‐African American) living in a closer distance class (as opposed to a further distance class). Results. The results show that as one moves further from a facility, the characteristics of the community reflect less and less the makeup near the site. The percentage of African Americans living near a chemical‐processing site tends to be much higher when compared to population characteristics further from the site. Conclusions. The study shows that distance does make a significant difference in the racial characteristics of the population from a chemical‐processing site. Using data reflecting accidental‐release scenarios, weather conditions, and the chemical process from the local community provides a more realistic basis for determining vulnerability zones.
Comparison of Molecular Tests for Detection and Quantification of Cell-Associated Cytomegalovirus DNA
Authors: Caliendo Angela M. , Yen-Lieberman Belinda , Baptista Jovana , Andersen Janet , Crumpacker Clyde , Schuurman Rob , Spector Stephen A. , Bremer James , Lurain Nell S.
Published: August 2003

A cell-based standard was developed to compare the COBAS Amplicor CMV Monitor test, the Hybrid Capture System CMV DNA test, and the NucliSens CMV test. The standard was prepared by infecting human foreskin fibroblasts (HFFs) with cytomegalovirus (CMV) strain AD169 at low multiplicity of infection (0.03) and harvesting the cells at 6 h postinfection. Buffy coat cells were added to produce concentrations of from 0 to 10
5
HFFs per 10
6
total cells. Five laboratories performed the Amplicor PCR test and two laboratories performed the NucliSens and Hybrid Capture tests. The Amplicor PCR test was 1.5 to 2.0 log
10
more sensitive than the Hybrid Capture test. The specificities of the Amplicor PCR and Hybrid Capture tests were 100 and 93.8%, respectively. The linear range of the Amplicor PCR and Hybrid Capture tests were 2 to 4.48 log
10
and 3.48 to at least 5.0 log
10
CMV target cells, respectively. The standard deviations of the Amplicor PCR and Hybrid Capture tests varied throughout their linear range, and for both tests the variability was greater for lower concentrations of input CMV DNA. These data allow the direct comparison of viral load values between the Amplicor and Hybrid Capture tests. The analytical sensitivity of the NucliSens test could not be determined by using the 6-h standard, because the low multiplicity of infection and short culture time did not allow for adequate transcription of pp67 late mRNA measured in the test. Extending the incubation time of the standard to 24 h increased the analytical sensitivity of the NucliSens test to 3.0 log
10
target cells.
Evidence for Genetic Linkage between the Gene Segments Encoding NSP4 and VP6 Proteins in Common and Reassortant Human Rotavirus Strains
Authors: Iturriza-Gòmara Miren , Anderton Emma , Kang Gagandeep , Gallimore Chris , Phillips Wendy , Desselberger Ulrich , Gray Jim
Published: August 2003

NSP4-encoding genes of 78 human rotavirus strains of common or reassortant genotypes were characterized by reverse transcription-PCR followed by sequencing and phylogenetic analysis. It was found that all the human strains characterized clustered into only two of the five known NSP4 genotypes. Linkage between NSP4 genotypes and VP6 subgroups was 100%, NSP4 genotype A being linked to VP6 of subgroup I (SGI) and NSP4 of genotype B being linked to VP6 of SGII. The diversity among the NSP4- and VP6-encoding genes was significantly less than that among the VP7 and VP4 genes in cocirculating human rotavirus strains. Whereas G and P types appear to be shared among different animal species and humans, the NSP4- and VP6-encoding genes appear to segregate according to their host of origin, suggesting that these two proteins may be host restriction determinants. The NSP4-VP6 association may be structurally determined during rotavirus replication (morphogenesis).
New Generation of Cell Culture Assay for Smallpox Vaccine Potency
Authors: Leparc-Goffart Isabelle , Poirier Bertrand , El Zaouk Annie , Tissier Marie-Hélène , Fuchs Florence
Published: August 2003

The potency of smallpox vaccines produced in the 1970s was tested by titration onto chorioallantoic membranes of fertilized hen eggs (CAM assay). The potency specification commonly approved for these vaccines was a titer above 10
8
pock-forming units per milliliter. We developed and validated a cell culture titration assay to have a more reliable potency test. The cell titration assay and the CAM assay were tested in parallel on 34 first-generation smallpox vaccine lots. These allowed us to demonstrate that a correlation does exist between the two titration techniques and to determine a new in-house specification for the cell titration method. This in vitro potency assay will allow us to test first-generation smallpox vaccines produced on the skin of living animals but will also give a hint of the potency specification that should be assigned for new generations of cell-derived smallpox vaccines.
Monitoring of Cytomegalovirus Infection in Solid-Organ Transplant Recipients by an Ultrasensitive Plasma PCR Assay
Authors: Hadaya Karine , Wunderli Werner , Deffernez Christelle , Martin Pierre-Yves , Mentha Gilles , Binet Isabelle , Perrin Luc , Kaiser Laurent
Published: August 2003

Early and accurate monitoring of cytomegalovirus (CMV) infection in solid-organ transplant recipients is of major importance. We have assessed the potential benefit of an ultrasensitive plasma-based PCR assay for renal transplant recipients. The pp65 CMV antigen (pp65 Ag) assay using leukocytes was employed as a routine test for the monitoring of CMV in 23 transplant recipients. We compared the pp65 antigenemia with the CMV load quantified by an ultrasensitive PCR (US-PCR) with a limit of detection of 20 CMV DNA copies/ml of plasma. CMV infection was detected in 215 (67%) of 321 plasma samples by the US-PCR compared with 124 (39%) of 321 samples by the pp65 Ag assay. The US-PCR assay permitted the detection of CMV infection episodes following transplantation a median of 12 days earlier than the pp65 Ag assay. Moreover, during CMV infection episodes, DNA detection by the US-PCR was consistently positive, whereas false negative results were frequently observed with the pp65 Ag assay. We found a good correlation between the two assays, and the peak viral loads were significantly higher in patients with CMV-related complications (median, 5,000 DNA copies/ml) than in those without symptoms (1,160 DNA copies/ml) (
P
= 0.048). In addition, patients that did not require preemptive therapy based on the results of the pp65 assay had CMV loads significantly lower (median, 36 DNA copies/ml) than those that needed treatment (median, 4,703 DNA copies/ml) (
P
< 0.001). These observations provided cutoff levels that could be applied in clinical practice. The ultrasensitive plasma-based PCR detected CMV infection episodes earlier and provided more consistent results than the pp65 Ag assay. This test could improve the monitoring of CMV infection or reactivation in renal transplant recipients.
Automated Extraction and Quantification of Human Cytomegalovirus DNA in Whole Blood by Real-Time PCR Assay
Authors: Mengelle C. , Sandres-Sauné K. , Pasquier C. , Rostaing L. , Mansuy J.-M. , Marty M. , Da Silva I. , Attal M. , Massip P. , Izopet J.
Published: August 2003

The measurement of human cytomegalovirus (HCMV) DNA in blood is becoming the standard method for monitoring HCMV infection in immune-suppressed and unsuppressed patients. As various blood compartments can be used, we have compared the HCMV DNA measured in whole blood (WB), peripheral blood leukocytes (PBL), and plasma by real-time PCR. We tested 286 samples: HCMV DNA was extracted automatically from WB and PBL with the MagNA Pure instrument (Roche Molecular Biochemicals) and manually from plasma samples. The HCMV DNA from WB, PBL, and plasma was measured by real-time Light Cycler PCR. Primers and probe were located in the UL 83 region. HCMV DNA was detected more frequently in WB (88.5%) than in the PBL (65.7%) (
P
< 0.0001) or the plasma (55.2%) (
P
< 0.0001). There was a good correlation between the positive results in WB and in PBL (
r
= 0.68;
P
< 0.0001), and 3.15 log
10
genome copies in 200,000 PBL, equivalent to the threshold value of 50 pp65-positive polymorphonuclear cells per 200,000 leukocytes, was equivalent to 3.4 log
10
genome copies in 200 μl of WB. WB was shown to be suitable for automated extraction and the quantitation of HCMV DNA by real-time Light Cycler PCR by analysis of serial samples from representative patients of various populations. This system may be very useful for monitoring of immune-suppressed and unsuppressed patients.
Genetic Diversity among
Escherichia coli
O157:H7 Isolates from Bovines Living on Farms in England and Wales
Authors: Liebana Ernesto , Smith Richard P. , Lindsay Elisabeth , McLaren Ian , Cassar Claire , Clifton-Hadley Felicity A. , Paiba Giles A.
Published: August 2003

Pulsed-field gel electrophoresis of
Escherichia coli
O157:H7 isolates (
n
= 228) from 122 healthy animals on 11 farms discriminated 57 types. Most clones were found only on individual farms. Numerous clones were found within each farm, with a prevalent clone normally found in several animals. A variety of clones were found within the different phage types.
Improved Molecular Detection of Dengue Virus Serotype 1 Variants
Authors: Reynes Jean-Marc , Ong Sivuth , Mey Channa , Ngan Chantha , Hoyer Stefan , Sall Amadou A.
Published: August 2003

The dengue virus molecular typing method described by Lanciotti and coworkers (R. S. Lanciotti, C. H. Calisher, D. J. Gubler, G. J. Chang, and A. Vance-Vorndam, J. Clin. Microbiol. 30:545-551, 1992) is used worldwide for diagnosis and surveillance. However, it failed to detect DENV-1 variants in Cambodia due to a point mutation. We describe an improvement of the method that allows the detection of additional DENV-1 strains, including potential variants.
Molecular Cloning, Expression, Self-Assembly, Antigenicity, and Seroepidemiology of a Genogroup II Norovirus Isolated in France
Authors: Nicollier-Jamot Béatrice , Pico Valérie , Pothier Pierre , Kohli Evelyne
Published: August 2003

Virus-like particles of Dijon171/96 virus, a genogroup II norovirus, were expressed in a baculovirus system and were used for a seroepidemiological study of 1,078 age-stratified human sera collected in Dijon, France. The results showed a seroprevalence of 74.1%. Furthermore, we showed that murine antibodies generated against recombinant Dijon171/96 virus, and human antibodies recognized discontinuous epitopes on the particles.
babA2-
and
cagA
-Positive
Helicobacter pylori
Strains Are Associated with Duodenal Ulcer and Gastric Carcinoma in Brazil
Authors: Oliveira Adriana Gonçalves , Santos Adriana , Guerra Juliana Becattini , Rocha Gifone Aguiar , Rocha Andreia Maria Camargos , Oliveira Celso Affonso , Cabral Mônica Maria Demas Álvares , Nogueira Ana Margarida Miguel Ferreira , Queiroz Dulciene Maria Magalhães
Published: August 2003

The
babA2
and
cagA
genes were investigated in 208 Brazilian
Helicobacter pylori
strains. A strong association between
babA2
and duodenal ulcer or gastric carcinoma was observed, even after adjusting for confounding factors, such as age, gender, and
cagA
status.
cagA
-positive strains were also independently associated with
H
.
pylori
-related diseases.
Moth sex chromatin probed by comparative genomic hybridization (CGH)
Authors: Sahara Ken , Marec Frantiek , Eickhoff Ulrike , Traut Walther
Published: August 2003

Comparative genomic hybridization (CGH) with a probe mixture of differently labeled genomic DNA from females and males highlighted the W chromosomes in mitotic plates and the W chromatin in polyploid interphase nuclei of the silkworm Bombyx mori, the flour moth Ephestia kuehniella, and the wax moth Galleria mellonella. The overproportionate fluorescence signal indicated an accumulation of repetitive sequences in the respective W chromosomes. Measurements of the fluorescence signals revealed two components, one that is present also in male DNA (non-W chromosomes) and another one that is present only in or preponderantly in female DNA (W chromosomes). While the W chromosomes of E. kuehniella and G. mellonella had both components, that of B. mori appeared to lack the latter component. Our results show that CGH can be applied to obtain a first estimate of the sequence composition of sex chromosomes in species from which otherwise little is known on the molecular level.Key words: Lepidoptera, comparative genomic hybridization, molecular evolution, W chromosome.
Genetic analysis and genome mapping inRaphanus
Authors: Bett Kirstin E , Lydiate Derek J
Published: August 2003

The first genetic map of the Raphanus genome was developed based on meiosis in a hybrid between Raphanus sativus (cultivated radish) and Raphanus raphanistrum (wild radish). This hybrid was used to produce a BC1population of 54 individuals and an F2population of 85 individuals. A total of 236 marker loci were assayed in these populations using a set of 144 informative Brassica RFLP probes previously used for genetic mapping in other crucifer species. The genetic maps derived from the BC1and F2populations were perfectly collinear and were integrated to produce a robust Raphanus map. Cytological observations demonstrated strict bivalent pairing in the R. sativus × R. raphanistrum hybrids. Productive pairing along the length of each chromosome was confirmed by the identification of nine extensive linkage groups and the lack of clustering of marker loci. Indeed, the distributions of both marker loci and crossovers was more random than those reported for other crop species. The genetic markers and the reference map of Raphanus will be of considerable value for future trait mapping and marker-assisted breeding in this crop, as well as in the intergenomic transfer of Raphanus genes into Brassica crops. The future benefits of comparative mapping with Arabidopsis and Brassica species are also discussed.Key words: radish, genetic map, RFLP markers, comparative mapping, segregation distortion.
Isolation, characterization, and analysis of Leymus-specific DNA sequences
Authors: Bödvarsdóttir Sigridur Klara , Anamthawat-Jónsson Kesara
Published: August 2003

Genomic Southern hybridization using labeled total genomic DNA of Leymus mollis as probe showed intense hybridization signals on all restriction enzyme digested DNA from five species of Leymus Hochst., and four species of Psathyrostachys Nevski. Experiments using the same L. mollis probe, but with unlabeled blocking DNA from Psathyrostachys, showed no hybridization at all. These two genera evidently had the same genomic content. Southern hybridization without blocking allowed identification of DNA fragments abundant in Leymus and Psathyrostachys. Fragments potentially specific to Leymus were cloned. Five repetitive DNA clones from L. mollis and L. arenarius were characterized: pLmIs1, pLmIs44, pLmIs51, pLmIs53, and pLaIs56. These clones hybridized to both Leymus and Psathyrostachys on Southern blots  no clone hybridized to only one of these genera. Both Southern blot and fluorescence in situ hybridization (FISH) experiments showed that all the clones contained dispersed repetitive sequences. They painted all and whole chromosomes uniformly except at centromeres, telomeres, and nucleolar organiser regions. Three of these clones, i.e., pLmIs1, pLmIs44, and pLmIs53, were essentially specific to Leymus and Psathyrostachys  little or no hybridization was detected in other genera such as Triticum, Hordeum, Thinopyrum, or Elymus. Sequence analysis further revealed that the clones were part of retroelements. In particular, the clone pLmIs44 produced hybridization profiles suitable for analysis of genetic relatedness among species. The present study shows that Leymus and Psathyrostachys share the same basic genome, Ns, and therefore provides strong evidence for combining these two genera.Key words: Triticeae, Leymus, Psathyrostachys, genome-specific sequences, retrotransposons.
Characterization of six wheat × Thinopyrum intermedium derivatives by GISH, RFLP, and multicolor GISH
Authors: Han F P , Fedak G , Benabdelmouna A , Armstrong K , Ouellet T
Published: August 2003

Restriction fragment length polymorphism (RFLP) analysis and multicolor genomic in situ hybridization (GISH) are useful tools to precisely characterize genetic stocks derived from crosses of wheat (Triticum aestivum) with Thinopyrum intermedium and Thinopyrum elongatum. The wheat × Th. intermedium derived stocks designated Z1, Z2, Z3, Z4, Z5, and Z6 were initially screened by multicolor GISH using Aegilops speltoides genomic DNA for blocking and various combinations of genomic DNA from Th. intermedium, Triticum urartu, and Aegilops tauschii for probes. The probing (GISH) results indicated that lines Z1 and Z3 were alien disomic addition lines with chromosome numbers of 2n = 44. Z2 was a substitution line in which chromosome 2D was substituted by a pair of Th. intermedium chromosomes; this was confirmed by RFLP and muticolour GISH. Z4 (2n = 44) contained two pairs of wheat  Th. intermedium translocated chromosomes; one pair involved A-genome chromosomes, the other involved D- and A-genome chromosomes. Z5 (2n = 44) contained one pair of wheat  Th. intermedium translocated chromosomes involving the D- and A-genome chromosomes of wheat. Z6 (2n = 44) contained one pair of chromosomes derived from Th. intermedium plus another pair of translocated chromosomes involving B-genome chromosomes of wheat. Line Z2 was of special interest because it has some resistance to infection by Fusarium graminearum.Key words: wheat, Thinopyrum intermedium, addition, substitution, and translocation lines, GISH, multicolor GISH, RFLP.
Genetics of drought tolerance during seed germination in tomato: inheritance and QTL mapping
Authors: Foolad M R , Zhang L P , Subbiah P
Published: August 2003

A BC1population (N = 1000) of an F1hybrid between a stress-sensitive Lycopersicon esculentum breeding line (NC84173; maternal and recurrent parent) and a germination stress-tolerant Lycopersicon pimpinellifolium accession (LA722) was evaluated for seed germination rate under drought stress (DS) (14% w/v polyethyleneglycol-8000, water potential approximately 680 kPa), and the most rapidly germinating seeds (first 3% to germinate) were selected. The 30 selected BC1seedlings were grown to maturity and self pollinated to produce BC1S1progeny seeds. Twenty of the 30 selected BC1S1progeny families were evaluated for germination rate under DS and their average performance was compared with that of a "nonselected" BC1S1population of the same cross. Results indicated that selection for rapid germination under DS significantly improved progeny germination rate under DS (selection gain = 19.6%), suggesting a realized heritability of 0.47 for rate of germination under DS in this population. The 30 selected BC1plants were subjected to restriction fragment length polymorphism (RFLP) analysis, and marker allele frequencies for 119 RFLP markers which spanned 1153 cM of the 12 tomato chromosomes were determined. A distributional extreme marker analysis, which measures statistical differences in marker allele frequencies between a selected and a nonselected population, detected four quantitative trait loci (QTLs) for rate of germination under DS in this population. Of these, two QTLs, located on chromosomes 1 and 9, were contributed by the L. pimpinellifolium donor parent and had larger effects than the other two QTLs, located on chromosomes 8 and 12, which were contributed by the L. esculentum recurrent parent. A few BC1S1families were identified with all or most of the identified QTLs and with germination rates comparable with that of LA722. These families should be useful for the development of germination drought-tolerant tomato lines using marker-assisted selection (MAS). The overall results indicate that drought tolerance during seed germination in tomato is genetically controlled and potentially could be improved by directional phenotypic selection or MAS.Key words: abiotic stress, distributional extreme analysis, heritability, selective genotyping, stress tolerance.
The nucleotypic effects of cellular DNA content in cartilaginous and ray-finned fishes
Authors: Hardie David C , Hebert Paul D.N
Published: August 2003

Cytological and organismal characteristics associated with cellular DNA content underpin most adaptionist interpretations of genome size variation. Since fishes are the only group of vertebrate for which relationships between genome size and key cellular parameters are uncertain, the cytological correlates of genome size were examined in this group. The cell and nuclear areas of erythrocytes showed a highly significant positive correlation with each other and with genome size across 22 cartilaginous and 201 ray-finned fishes. Regressions remained significant at all taxonomic levels, as well as among different fish lineages. However, the results revealed that cartilaginous fishes possess higher cytogenomic ratios than ray-finned fishes, as do cold-water fishes relative to their warm-water counterparts. Increases in genome size owing to ploidy shifts were found to influence cell and nucleus size in an immediate and causative manner, an effect that persists in ancient polyploid lineages. These correlations with cytological parameters known to have important influences on organismal phenotypes support an adaptive interpretation for genome size variation in fishes.Key words: evolution, genome size, DNA content, cell size, erythrocyte size, fishes, nucleotypic effect.
Molecular genetic linkage maps for allotetraploidLeymuswildryes (Gramineae: Triticeae)
Authors: Wu Xiaolei , Larson Steven R , Hu Zanmin , Palazzo Antonio J , Jones Thomas A , Wang Richard R-C , Jensen Kevin B , Chatterton N Jerry
Published: August 2003

Molecular genetic maps were constructed for two full-sib populations, TTC1 and TTC2, derived from two Leymus triticoides × Leymus cinereus hybrids and one common Leymus triticoides tester. Informative DNA markers were detected using 21 EcoRIMseI and 17 PstIMseI AFLP primer combinations, 36 anchored SSR or STS primer pairs, and 9 anchored RFLP probes. The 164-sib TTC1 map includes 1069 AFLP markers and 38 anchor loci in 14 linkage groups spanning 2001 cM. The 170-sib TTC2 map contains 1002 AFLP markers and 36 anchor loci in 14 linkage groups spanning 2066 cM. Some 488 homologous AFLP loci and 24 anchor markers detected in both populations showed similar map order. Thus, 1583 AFLP markers and 50 anchor loci were mapped into 14 linkage groups, which evidently correspond to the 14 chromosomes of allotetraploid Leymus (2n = 4x = 28). Synteny of two or more anchor markers from each of the seven homoeologous wheat and barley chromosomes was detected for 12 of the 14 Leymus linkage groups. Moreover, two distinct sets of genome-specific STS markers were identified in these allotetraploid Leymus species. These Leymus genetic maps and populations will provide a useful system to evaluate the inheritance of functionally important traits of two divergent perennial grass species.Key words: AFLP, perennial grasses, RFLP, STS, SSR.
A combined RFLPSSRAFLP map of tetraploid cotton based on aGossypium hirsutum×Gossypium barbadensebackcross population
Authors: Lacape J -M , Nguyen T -B , Thibivilliers S , Bojinov B , Courtois B , Cantrell R G , Burr B , Hau B
Published: August 2003

An interspecific Gossypium hirsutum × Gossypium barbadense backcross population of 75 BC1plants was evaluated for 1014 markers. The map consists of 888 loci, including 465 AFLPs, 229 SSRs, 192 RFLPs, and 2 morphological markers, ordered in 37 linkage groups that represent most if not all of the 26 chromosomes, altogether spanning 4400 cM. Loci were not evenly distributed over linkage groups, and 18 of the 26 long groups had a single dense region. This paper proposes a partially revised list of the 13 pairs of homoeologous A/D chromosomes of the 2n = 4x = 52 tetraploid cotton genome. The major revisions, which involve the c3c17, c4c22, c5D08, and c10c20 homoeologous pairs, are based on the mapping of 68 SSR and RFLP loci with a known chromosome assignment, as well as on comparative alignments with previously published G. hirsutum × G. barbadense maps. The overall congruency in the locus orders and distances of common SSR and RFLP loci in these maps allows for an estimation of the consensus length that reaches a minimum of 5500 cM, and is encouraging for future efforts aimed at developing an integrated map of cultivated cotton. The present map also provides a firm framework for precision mapping of Mendelian components of quantitative traits in cotton.Key words: cotton, genetic mapping, RFLP, microsatellite, AFLP.
Topological Charge of Noncommutative ADHM Instanton
Authors: Tian Yu , Zhu Chuan-Jie , Song Xing-Chang
Published: August 2003

We analytically calculate the topological charge of general noncommutative U (N) instantons using the Corrigan's identity and find that the result is exactly the instanton number k, which appears in the noncommutative ADHM construction as the dimension of the vector space V. This result coincides with the corresponding fact in the commutative case.
Doubly Special Relativity with Light-Cone Deformation
Authors: Błaut A. , Daszkiewicz M. , Kowalski-Glikman J.
Published: August 2003

We propose a new Doubly Special Relativity theory based on the generalization of the κ-deformation of the Poincaré algebra acting along one of the null directions. We recall the quantum Hopf structure of such deformed Poincaré algebra and use it to derive the phase space commutation relations. As in the DSR based on the standard quantum κ-Poincaré algebra we find that the spacetime is noncommutative. We investigate the fate of the properties of Special Relativity in the null basis: the split of the algebra of Lorentz and momentum generators into kinematical and dynamical parts, the action of the kinematical boost M+-, and the emergence of the two-dimensional Galilean symmetry.
On Many-Valued Partitions and Many-Valued Equivalence Relations
Authors: Demirci Mustafa
Published: August 2003

For a fixed integral commutative cl-monoid M=(L, ≤, *), introducing the notions of M-partitions and M-equivalence relations as the extensions of T-partitions and T-equivalence relations to the integral commutative cl-monoid M=(L, ≤, *), respectively, it is shown that the previous approaches on T-partitions and T-equivalence relations can be unified, and most of the results in these works can be easily stated based on the integral commutative cl-monoid M=(L, ≤, *). Modifying the notion of T-redundancy of finite family of fuzzy sets of a nonempty ordinary set X, it is extended to arbitrary family of L-fuzzy sets on the basis of the integral commutative cl-monoid M, and is shown that the proposed definition has more desirable properties than the previous one. Furthermore, handling the works of Höhle, Klawonn, Gebhardt and Kruse on fuzzy partitions and fuzzy equivalence relations, some of their results are improved, and several new results in this direction are pointed out.
Stereotactic Interstitial Radiosurgery with a Miniature X-Ray Device in the Minimally Invasive Treatment of Selected Tumors in the Thalamus and the Basal Ganglia
Authors: Gallina Pasquale , Francescon Paolo , Cavedon Carlo , Casamassima Franco , Mungai Raffaello , Perrini Paolo , Russo Serenella , Di Lorenzo Nicola
Published: August 2003

The aim of this study was to evaluate the role of interstitial radiosurgery (IR) using the photon radiosurgery system (PRS) in the treatment of selected tumors within the thalamus and the basal ganglia. The PRS is a miniature X-ray generator that was developed for interstitial irradiation. This series included 14 patients (5 with glioblastomas, 4 with low-grade astrocytomas and 5 with metastases) harboring spheroidal lesions with dimensions ranging from 13 to 42 mm (mean 30 mm). After stereotactic biopsy, a radiation dose ranging from 6 to 15.4 Gy (mean 11.3 Gy) was delivered at the target volume margins. Follow-up varied from 3 to 26 months (mean 10.2 months). In the group of glioblastomas, 3 patients died (3–12 months after the procedure) because of tumor progression, while the remaining had tumor control. Two patients with metastases died from systemic disease (4–9 months after the treatment), and 3 were alive and well at the end of the study. Local control was achieved in all metastases. Patients with low-grade astrocytomas were well and imaging studies showed tumor control PRS IR is a minimally invasive procedure for the treatment of selected glial or secondary brain tumors. Compared to conventional radiosurgery (brachytherapy and external radiosurgery), PRS IR presents dose delivery characteristics useful for the treatment of tumors in the thalamus and basal ganglia, without inconveniences such as handling radioisotopes, the need of expensive facilities and radiation protection measures. Although the clinical value needs further investigations, PRS IR seems to be effective in metastases while it provides less benefit in malignant gliomas. PRS IR could have a major role in the treatment of low-grade astrocytomas.
Bilateral Pallidal Stimulation for Cervical Dystonia
Authors: Goto Satoshi , Mita Shuji , Ushio Yukitaka
Published: August 2003

We sought to identify optimal paradigms of bilateral globus pallidus internus (GPi) stimulation in 3 subsequent patients with severe cervical dystonia. At low frequency stimulation (50–60 Hz) with wide pulse width (500 µs) and high amplitude (4.5–8.0 V), we observed immediate and consistent improvement of dystonia and dystonia-associated pain. Stimulation of the posteroventral portion of the GPi led to pronounced alleviation of dystonia; stimulation of the anterodorsal portion or at the dorsal border of the GPi resulted in significant worsening of symptoms. The therapeutic benefit obtained by using the optimal stimulation parameters continues and has lasted for at least 1 year in each patient.
Linac Radiosurgery for Brain Metastasis of Melanoma
Authors: Noël Georges , Simon Jean Marc , Valery Charles-Ambroise , Cornu Philippe , Boisserie Gilbert , Ledu Dominique , Hasboun Dominique , Tep Bernadette , Delattre Jean-Yves , Marsault Claude , Baillet François , Mazeron Jean-Jacques
Published: August 2003

Purpose: To evaluate the efficacy and toxicity of stereotactic radiotherapy in the treatment of brain metastases of melanoma. Patients and Methods: From 1994 to 2001, 25 patients presenting with 61 metastases of cutaneous melanoma were treated with radiosurgery. Median age was 47 years (range: 25–73 years) and median Karnofski performance status 80 (range: 50–100). Twenty patients had one radiosurgery, 5 had two or three. Median metastasis diameter was 21 mm (range: 6–54.4 mm), and median metastasis volume was 1.7 cm3 (range: 0.4–25.6 cm3). Irradiation was delivered by a linear accelerator. Median minimal dose was 14.1 Gy (range: 10–19.4 Gy), and median maximal dose was 20.5 Gy (range: 16–48 Gy). Results: Mean follow-up was 12.6 months (range: 1–85 months). Five metastases progressed (9.8%), 2–12 months after radiosurgery. Three-, 6- and 12-month local control rates were 95 ± 3, 90 ± 5 and 84 ± 7%, respectively. By univariate analysis, only absence of extracranial tumor was a prognostic factor of local control. Three-, 6- and 12-month brain-disease-free survival rates were 75 ± 9, 68 ± 11 and 38 ± 13%, respectively. According to univariate analysis, only the Score Index for Radiosurgery in brain metastases (SIR) was a prognostic factor of brain-event-free survival (p = 0.03). Median survival was 8 months. Three-, 6- and 12-month overall survival rates were 75 ± 9, 53 ± 10, and 29 ± 10%, respectively. According to univariate analysis, extracranial controlled disease status (p = 0.03), and SIR (p = 0.04) were prognostic factors for overall survival. According to multivariate analysis, none was an independent prognosticator for overall survival. Complications were minimal. Conclusion: Radiosurgical treatment of brain metastases of melanoma is effective and accurate. The use of radiosurgery alone is an appropriate management strategy for many patients with brain metastases of melanoma.
Middle Cerebral Artery Stenosis in Type II Diabetic Chinese Patients Is Associated with Conventional Risk Factors but Not with Polymorphisms of the Renin-Angiotensin System Genes
Authors: Thomas G. Neil , Wen Lin Jian , Lam Wynnie W.M. , Tomlinson Brian , Yeung Vincent , Chan Juliana C.N. , Sing Wong Ka
Published: August 2003

Background: Conventional and genetic risk factors have been reported to play a role in the pathogenesis of ischaemic stroke, and differences may explain the heterogeneity of disease presentation in different populations. In Chinese, middle cerebral artery (MCA) stenosis is the most commonly identified intracranial vascular lesion. The involvement of renin-angiotensin system (RAS) gene polymorphisms in this condition has not been determined. Objectives: To determine whether conventional and RAS genetic vascular risk factors are associated with MCA stenosis, asymptomatic Chinese type II diabetic patients with and without MCA stenosis matched for age, gender and diabetes duration were compared. Methods: Biochemical parameters and the genotype and allele frequencies of three RAS gene polymorphisms, the angiotensin-converting enzyme (ACE) insertion/deletion, angiotensinogen (AGT) M235T and angiotensin II type 1 receptor (AT1R) A1166C polymorphisms were then compared between 217 diabetics with and 490 matched diabetic controls without MCA stenosis selected from 2,202 diabetics. Results: MCA stenosis was associated with significantly increased systolic blood pressure, LDL-cholesterol and albuminuria, yet diastolic blood pressure and glucose levels were lower. There was an increased prevalence of hypertension and use of blood pressure-lowering agents in the MCA stenosis patients. Albuminuria was also more commonly found in these patients. Hypertensive status, systolic blood pressure and albuminuria were strong, independent predictors of the presence of MCA stenosis. No differences in the RAS polymorphism distributions were observed between patients with and without MCA stenosis. Conclusions: In these asymptomatic type II diabetics, blood pressure indices and albuminuria, but not RAS gene polymorphism, were closely associated with MCA stenosis.
A Prospective Analysis of Risk Factors for White Matter Disease in the Brain Stem
Authors: Ding Jingzhong , Nieto F. Javier , Beauchamp Norman J. , Longstreth Jr. W.T. , Manolio Teri A. , Hetmanski Jacqueline B. , Fried Linda P.
Published: August 2003

Background and Purpose: White matter disease (WMD) in the brain stem may be a predictor of poor clinical outcome, independent of WMD in the periventricular and subcortical areas of the brain. Many cardiovascular risk factors such as older age, hypertension, and smoking have been suggested as risk factors for WMD in the periventricular and subcortical areas of the brain. However, no epidemiologic study has examined the associations between cardiovascular risk factors and WMD in the brain stem. Methods: A total of 789 participants, aged 65 years or older, from the Cardiovascular Health Study constituted the present study population. WMD, defined as hyperintensive lesions on magnetic resonance imaging (MRI), in the brain stem was measured in 1992/1993 and 1997/1998. Results: Of the 789 participants, 212 (26.9%) had WMD in the brain stem in 1997/1998. In multivariate logistic regression analysis, the presence of WMD in the brain stem in 1997/1998 was significantly associated with several variables measured in 1992/1993: an increase by 5 years of age (OR = 1.51, 95% CI: 1.25–1.83), a 10-pack-years increase in smoking (OR = 1.12, 95% CI: 1.04–1.21), a 0.1-liter increase in first-second forced expiratory volume (OR = 0.95, 95% CI: 0.92–0.99), a 1 µmol/l increase in fibrinogen level (OR = 1.13, 95% CI: 1.03–1.23), and MRI infarction (OR = 2.58, 95% CI: 1.78–3.74). Excluding those (n = 167) with WMD in the brain stem in 1992/1993, the pattern remained. Hypertension was not associated with WMD in the brain stem. Conclusions: Increased age, smoking, lower forced expiratory volume, increased fibrinogen level, and MRI infarction, but not hypertension, may be independent risk factors for WMD in the brain stem in older adults.
ICF syndrome cells as a model system for studying X chromosome inactivation
Authors: Gartler S.M. , Hansen R.S.
Published: August 2003

Mutations in the DNMT3B DNA methyltransferase gene cause the ICF immunodeficiency syndrome. The targets of this DNA methyltransferase are CpG-rich heterochromatic regions, including pericentromeric satellites and the inactive X chromosome. The abnormal hypomethylation in ICF cells provides an important model system for determining the relationships between replication time, CpG island methylation, chromatin structure, and gene silencing in X chromosome inactivation.
Effect of Tsix disruption on Xist expression in male ES cells
Authors: Sado T. , Li E. , Sasaki H.
Published: August 2003

Xist and its antisense partner, Tsix, encode non-coding RNAs and play key roles in X chromosome inactivation. Targeted disruption of Tsix causes ectopic expression of Xist in the extraembryonic tissues upon maternal transmission, which subsequently results in embryonic lethality due to inactivation of both X chromosomes in females and a single X chromosome in males. Tsix, therefore, plays a crucial role in maintaining the silenced state of Xist in cis and regulates the imprinted X inactivation in the extraembryonic tissues. In this study, we examined the effect of Tsix disruption on Xist expression in the embryonic lineage using embryonic stem (ES) cells as a model system. Upon differentiation, Xist is ectopically activated in a subset of the nuclei of male ES cells harboring the Tsix-deficient X chromosome. Such ectopic expression, however, eventually ceased during prolonged culture. It is likely that surveillance by the X chromosome counting mechanism somehow shuts off the ectopic expression of Xist before inactivation of the X chromosome.
Chromosome evolution in fish: sex chromosome variability in Eigenmannia virescens (Gymnotiformes: Sternopygidae)
Authors: de Almeida-Toledo L.F. , Daniel-Silva M.F.Z. , Moysés C.B. , Fonteles S.B.A. , Lopes C.E. , Akama A. , Foresti F.
Published: August 2003

New data are presented on the sex chromosomes of the fish species Eigenmannia virescens (Gymnotiformes, Sternopygidae). A new finding, involving the occurrence of ZZ/ZW sex chromosomes, is described in specimens sampled from the São Francisco and Amazon river basins in Brazil. All individuals had a chromosome number of 2n = 38. The homologs of the sex chromosome pair from the São Francisco river basin sample differed only in their morphology, while those from the Amazonian sample differed both in morphology and heterochromatin pattern. A possible model for the evolution of the sex chromosomes in E. virescens is proposed, including data from populations from the Paraná (Brazil) river basin, in which male heterogamety has already been described. The occurrence of different sex chromosome systems in species and populations of the neotropical freshwater fish fauna is discussed.
The prototype of sex chromosomes found in Korean populations of Rana rugosa
Authors: Ogata M. , Lee J.-Y. , Kim S. , Ohtani H. , Sekiya K. , Igarashi T. , Hasegawa Y. , Ichikawa Y. , Miura I.
Published: August 2003

The seventh largest chromosome in Japanese populations of the frog Rana rugosa morphologically evolved as a sex chromosome. The sex chromosome is XX/XY type in one geographic form and ZZ/ZW type in another. In contrast, the seventh chromosomes are still homomorphic between the sexes in the other two geographic forms: they are more subtelocentric in the Kanto form and subtelocentric in the western Japanese form. To identify a prototype of the sex chromosomes, we extended our investigation in this study to the Korean form, which is supposed to be close to the phylogenetic origin of this species. The karyotype, a sex-linked gene sequence, and mecha- nisms of sex determination and gonadal differentiation were all examined. In addition, phylogenetic analyses were performed based on mitochondrial gene sequences and the results of crossings between the Korean and Japanese forms. As a consequence, the more subtelocentric seventh chromosome, shared by the Korean and Japanese Kanto forms, was concluded to be the prototype of the sex chromosomes. Starting at the prototype, a whole process of morphological sex chromosome evolution was reconstructed.