bluuebunny/crossref_metadata_2025_split huggingface dataset:
Posttranslational Modification of 6-Phosphofructo-1-Kinase in
Aspergillus niger
Authors: Mesojednik Suzana , Legiša Matic 
Published: March 2005

ABSTRACT

Two different enzymes exhibiting 6-phosphofructo-1-kinase (PFK1) activity were isolated from the mycelium of
Aspergillus niger
: the native enzyme with a molecular mass of 85 kDa, which corresponded to the calculated molecular mass of the deduced amino acid sequence of the
A. niger pfkA
gene, and a shorter protein of approximately 49 kDa. A fragment of identical size also was obtained in vitro by the proteolytic digestion of the partially purified native PFK1 with proteinase K. When PFK1 activity was measured during the proteolytic degradation of the native protein, it was found to be lost after 1 h of incubation, but it was reestablished after induction of phosphorylation by adding the catalytic subunit of cyclic AMP-dependent protein kinase to the system. By determining kinetic parameters, different ratios of activities measured at ATP concentrations of 0.1 and 1 mM were detected with fragmented PFK1, as with the native enzyme. Fructose-2,6-biphosphate significantly increased the
V
max
of the fragmented protein, while it had virtually no effect on the native protein. The native enzyme could be purified only from the early stages of growth on a minimal medium, while the 49-kDa fragment appeared later and was activated at the time of a sudden change in the growth rate. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of sequential purifications of PFK1 enzymes by affinity chromatography during the early stages of the fungal development suggested spontaneous posttranslational modification of the native PFK1 in
A. niger
cells, while from the kinetic parameters determined for both isolated forms it could be concluded that the fragmented enzyme might be more efficient under physiological conditions.
Quantitative-PCR Assessment of
Cryptosporidium parvum
Cell Culture Infection
Authors: Di Giovanni George D. , LeChevallier Mark W. 
Published: March 2005

ABSTRACT

A quantitative TaqMan PCR method was developed for assessing the
Cryptosporidium parvum
infection of in vitro cultivated human ileocecal adenocarcinoma (HCT-8) cell cultures. This method, termed cell culture quantitative sequence detection (CC-QSD), has numerous applications, several of which are presented. CC-QSD was used to investigate parasite infection in cell culture over time, the effects of oocyst treatment on infectivity and infectivity assessment of different
C. parvum
isolates. CC-QSD revealed that cell culture infection at 24 and 48 h postinoculation was approximately 20 and 60%, respectively, of the endpoint 72-h postinoculation infection. Evaluation of three different lots of
C. parvum
Iowa isolate oocysts revealed that the mean infection of 0.1 N HCl-treated oocysts was only 36% of the infection obtained with oocysts treated with acidified Hanks' balanced salt solution containing 1% trypsin. CC-QSD comparison of the
C. parvum
Iowa and TAMU isolates revealed significantly higher levels of infection for the TAMU isolate, which agrees with and supports previous human, animal, and cell culture studies. CC-QSD has the potential to aid in the optimization of
Cryptosporidium
cell culture methods and facilitate quantitative evaluation of cell culture infectivity experiments.
In Vivo Monitoring of Obligate Biotrophic Pathogen Growth by Kinetic PCR
Authors: Boyle Brian , Hamelin Richard C. , Séguin Armand 
Published: March 2005

ABSTRACT

The plant kingdom is constantly challenged by a battery of evolving pathogens. New species or races of pathogens are discovered on crops that were initially bred for disease resistance, and globalization is facilitating the movement of exotic pests. Among these pests, obligate biotrophic parasites make up some of the most damaging groups and have been particularly challenging to study. Here we demonstrate the utility of kinetic PCR (kPCR) (real-time PCR, quantitative PCR) to assess the growth of poplar rust, caused by
Melampsora
species, by quantification of pathogen DNA. kPCR allowed the construction of reliable growth curves from inoculation through the final stages of uredinial maturation, as well as pathogen monitoring before symptoms become visible. Growth parameters, such as latency period, generation time in logarithmic growth, and the increase in DNA mass at saturation, were compared in compatible, incompatible, and nonhost interactions. Pathogen growth was monitored in different applications dealing with plant pathology, such as host and pathogen diversity and transgenic crop improvement. Finally, the capacity of kPCR to differentiate pathogens in the same sample has broad molecular ecology applications for dynamically monitoring the growth of fungi in their environments or in mixed populations or to measure the efficacy of pest control strategies.
Characterization of the Highly Efficient Sucrose Isomerase from
Pantoea dispersa
UQ68J and Cloning of the Sucrose Isomerase Gene
Authors: Wu Luguang , Birch Robert G. 
Published: March 2005

ABSTRACT

Sucrose isomerase (SI) genes from
Pantoea dispersa
UQ68J,
Klebsiella planticola
UQ14S, and
Erwinia rhapontici
WAC2928 were cloned and expressed in
Escherichia coli
. The predicted products of the UQ14S and WAC2928 genes were similar to known SIs. The UQ68J SI differed substantially, and it showed the highest isomaltulose-producing efficiency in
E. coli
cells. The purified recombinant WAC2928 SI was unstable, whereas purified UQ68J and UQ14S SIs were very stable. UQ68J SI activity was optimal at pH 5 and 30 to 35°C, and it produced a high ratio of isomaltulose to trehalulose (>22:1) across its pH and temperature ranges for activity (pH 4 to 7 and 20 to 50°C). In contrast, UQ14S SI showed optimal activity at pH 6 and 35°C and produced a lower ratio of isomaltulose to trehalulose (<8:1) across its pH and temperature ranges for activity. UQ68J SI had much higher catalytic efficiency; the

K
m

was 39.9 mM, the
V
max
was 638 U mg
−1
, and the
K
cat
/

K
m

was 1.79 × 10
4
M
−1
s
−1
, compared to a

K
m

of 76.0 mM, a
V
max
of 423 U mg
−1
, and a
K
cat
/

K
m

of 0.62 × 10
4
M
−1
s
−1
for UQ14S SI. UQ68J SI also showed no apparent reverse reaction producing glucose, fructose, or trehalulose from isomaltulose. These properties of the
P. dispersa
UQ68J enzyme are exceptional among purified SIs, and they indicate likely differences in the mechanism at the enzyme active site. They may favor the production of isomaltulose as an inhibitor of competing microbes in high-sucrose environments, and they are likely to be highly beneficial for industrial production of isomaltulose.
Genomic Comparisons of
Salmonella enterica
Serovar Dublin, Agona, and Typhimurium Strains Recently Isolated from Milk Filters and Bovine Samples from Ireland, Using a
Salmonella
Microarray
Authors: Reen F. J. , Boyd E. F. , Porwollik S. , Murphy B. P. , Gilroy D. , Fanning S. , McClelland M. 
Published: March 2005

ABSTRACT

Salmonella
-induced enterocolitis is the leading food-borne illness with a lethal outcome and causes millions of cases of gastroenteritis each year. We examined genomic variation among 12 environmental, veterinary, and clinical
Salmonella enterica
serovar Dublin, Agona, and Typhimurium strains isolated in Ireland between 2000 and 2003, as well as two clinical isolates from Canada and four archival isolates, which belonged to serovars Dublin and Agona. Using DNA-DNA hybridization to a microarray consisting of most of the predicted protein-encoding sequences of the
S. enterica
serovar Typhimurium LT2 genome, we identified a number of genomic regions that were absent in one or more serovars. The 34 genomic regions encoded proteins involved in sugar metabolism, transport, fimbrial and phage biogenesis, and transcriptional regulation, as well as inner and outer membrane-associated proteins. Two of the four prophages identified in strain LT2, prophages Gifsy-1 and Gifsy-2, were present in all six serovar Typhimurium strains examined. Prophage Fels-1 was absent from all 18 isolates examined, and Fels-2 was completely absent from the serovar Typhimurium isolates and the
Salmonella
Reference Collection B serovar Dublin strain Du2. All five
Salmonella
pathogenicity islands were present in all isolates. Plasmid pSLT was absent from all serovar Agona isolates, and only homologues of the
spv
genes were present in eight of the nine serovar Dublin strains. Only limited intraserovar diversity was found among the nine serovar Dublin, three serovar Agona, and six serovar Typhimurium isolates examined even though these isolates had extensive geographic, temporal, and source differences.
Dynamics of Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase Gene Expression in the Coccolithophorid
Coccolithus pelagicus
during a Tracer Release Experiment in the Northeast Atlantic
Authors: Wyman Michael , Davies John T. , Hodgson Sylvia , Tarran Glen A. , Purdie Duncan A. 
Published: March 2005

ABSTRACT

We report a pronounced diel rhythm in ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO) gene expression in a natural population of the coccolithophorid
Coccolithus pelagicus
sampled during a Lagrangian experiment in the Northeast Atlantic. Our observations show that there is greater heterogeneity in the temporal regulation of RubisCO expression among planktonic chromophytes than has been reported hitherto.
Optical Brighteners Do Not Influence Covert Baculovirus Infection of
Spodoptera frugiperda
Authors: Martínez Ana-Mabel , Williams Trevor , López-Ferber Miguel , Caballero Primitivo 
Published: March 2005

ABSTRACT

Covert infection with
Spodoptera frugiperda
multiple nucleopolyhedrovirus, detected by reverse transcription-PCR of virus gene transcripts (
ie-0
and
polh
), was not significantly affected by the presence of an optical brightener (Tinopal UNPA-GX), indicating no change in virus virulence. Detection of the covert infection was dependent on insect life stage and the viral mRNA used for diagnosis.
Structural characterization of the antigenic capsular polysaccharide and lipopolysaccharide O-chain produced byActinobacillus pleuropneumoniaeserotype 15
Authors: Perry Malcolm B , MacLean Leann L , Vinogradov Evgeny 
Published: March 2005

The specific capsular polysaccharide produced by Actinobacillus pleuropneumoniae serotype 15 was determined to be a high-molecular-mass polymer having [α]D+ 69° (water) and composed of a linear backbone of phosphate diester linked disaccharide units of 2-acetamido-2-deoxy-D-glucose (D-GlcNAc) and 2-acetamido-2-deoxy-D-galactose (D-GalNAc) residues (1:1). Thirty percent of the D-GalNAc residues were substituted at O-4 by β-D-galactopyranose (β-D-Galp) residues. Through the application of chemical and NMR methods, the capsule, which defines the serotype specificity of the bacterium, was found to have the structure                        [Formula: see text]The O-polysaccharide (O-PS) component of the A. pleuro pneumoniae serotype 15 lipopolysaccharide (LPS) was characterized as a linear unbranched polymer of repeating pentasaccharide units composed of D-glucose (2 parts) and D-galactose (3 parts), shown to have the structure[Formula: see text]The O-PS was chemically identical with the O-antigen previously identified in the LPSs produced by A. pleuro pneumoniae serotypes 3 and 8. Key words: Capsule, lipopolysaccharide, Actinobacillus pleuropneumoniae serotype 15.
Nuclear genome size and genomic distribution of ribosomal DNA in <i>Musa</i> and <i>Ensete</i> (Musaceae): taxonomic implications
Authors: Bartoš J. , Alkhimova O. , Doleželová M. , De Langhe E. , Doležel J. 
Published: March 2005

Nuclear DNA content and genomic distributions of 5S and 45S rDNA were examined in nineteen diploid accessions of the genus <i>Musa</i> representing its four sections <i>Eumusa</i>, <i>Rhodochlamys</i>, <i>Callimusa</i> and <i>Australimusa</i>, and in <i>Ensete gilletii</i>, which was the outgroup in this study. In the <i>Eumusa</i> (x = 11), 2C DNA content ranged from 1.130 to 1.377 pg, <i>M. balbisiana</i> having the lowest DNA content of all sections. <i>M. beccarii</i> (x = 9), a representative of <i>Callimusa</i>, had the highest 2C nuclear DNA content (1.561 pg). Species belonging to <i>Rhodochlamys</i> (x = 11) and <i>Australimusa</i> (x = 10) had 2C DNA contents ranging from 1.191 to 1.299 pg and from 1.435 to 1.547 pg, respectively. <i>E. gilletii</i> (x = 9) had 2C DNA content of 1.210 pg. The number of 5S rDNA loci in <i>Musa</i> varied from 4 to 8 per diploid cell. While different numbers of 5S rDNA loci were observed within <i>Eumusa</i> and <i>Rhodochlamys</i>, four 5S rDNA loci were observed in all accessions of <i>Australimusa</i>. <i>M. beccarii (Callimusa)</i> and <i>E. gilletii</i> contained 5S rRNA gene clusters on five and six chromosomes, respectively. The number of 45S rDNA loci was conserved within individual sections. Hierarchical cluster analysis of genome size, number of chromosomes and 45S rDNA sites suggested a close relationship between <i>Rhodochlamys</i> and <i>Eumusa</i>; <i>Australimusa</i> was clearly separated as were <i>M. beccarii</i> and <i>E. gilletii</i>. Within the <i>Eumusa-Rhodochlamys</i> group, <i>M. balbisiana</i>, <i>M. schizocarpa</i> and <i>M. ornata</i> formed distinct subgroups, clearly separated from the accessions of <i>M. acuminata</i>, <i>M. mannii</i>, <i>M. laterita</i> and <i>M. velutina</i>, which formed a tight subgroup. The results expand the knowledge of genome size and genomic distribution of ribosomal DNA in <i>Musa</i> and <i>Ensete</i>. They aid in clarification of the taxonomical classification of <i>Musa</i> and show a need to supplement the analyses on the DNA sequence level with cytogenetic studies.
A strategy to investigate the plant meiotic proteome
Authors: Sánchez-Morán E. , Mercier R. , Higgins J.D. , Armstrong S.J. , Jones G.H. , Franklin F.C.H. 
Published: March 2005

The analysis of meiosis in higher plants has benefited considerably in recent years from the completion of the genome sequence of the model plant <i>Arabidopsis thaliana</i> and the development of cytological techniques for this species. A combination of forward and reverse genetics has provided important routes toward the identification of meiotic genes in <i>Arabidopsis.</i> Nevertheless identification of certain meiotic genes remains a challenge due to problems such as limited sequence conservation between species, existence of closely related gene families and in some cases functional redundancy between gene family members. Hence there is a requirement to develop new experimental approaches that can be used in conjunction with existing methods to enable a greater range of plant meiotic genes to be identified. As one potential route towards this goal we have initiated a proteomics-based approach. Unfortunately, the small size of <i>Arabidopsis</i> anthers makes an analysis in this species technically very difficult. Therefore we have initially focussed on <i>Brassica oleracea</i> which is closely related to <i>Arabidopsis,</i> but has the advantage of possessing significantly larger anthers. The basic strategy has been to use peptide mass-finger printing and matrix-assisted laser desorption ionization time of flight mass spectrometry to analyse proteins expressed in meiocytes during prophase I of meiosis. Initial experiments based on the analysis of proteins from staged anther tissue proved disappointing due to the low level of detection of proteins associated with meiosis. However, by extruding meiocytes in early prophase I from individual anthers prior to analysis a significant enrichment of meiotic proteins has been achieved. Analysis suggests that at least 18% of the proteins identified by this route have a putative meiotic function and that this figure could be as high as one-third of the total. Approaches to increase the enrichment of proteins involved in meiotic recombination and chromosome synapsis are also described.
Centromere-specific repetitive sequences from <i>Torenia</i>, a model plant for interspecific fertilization, and whole-mount FISH of its interspecific hybrid embryos
Authors: Kikuchi S. , Kishii M. , Shimizu M. , Tsujimoto H. 
Published: March 2005

<i>Torenia fournieri</i> is a good model plant to study fertilization in plants because it is easy to observe the fertilization process due to the protruding nature of the embryo sac. To study the location and movement of chromosomes and their centromeres in early embryogenesis of interspecific hybrid plants, we isolated two families of centromere-specific tandem repetitive sequences from <i>T. fournieri</i> and <i>T. bailonii</i>, and named them the “TCEN-family” and “BCEN-family”, respectively. Both sequences consisted of a repeat unit of 52 bp located in the pericentric and centric heterochromatins. All signals of both sequences were prominent, but their intensity varied among the chromosomes. DNA-blot hybridization indicated the presence of similar sequences of TCEN-family in <i>T. concolor</i>, <i>N. caerulea</i>, and “Summer Wave”, whereas the BCEN-family was found only in <i>T. bailonii</i>, thus indicating the wide or specific distribution of their repetitive families observed. We also applied whole-mount FISH to the interspecific hybrid embryos by using TCEN- and BCEN-family sequences as probes. Our results suggest that whole-mount FISH with the species-specific centromere sequences as probes is an ideal method to analyze the dynamics of chromosomes and centromeres in interspecific fertilization and early embryogenesis.
Development and characterization of potato-<i>Solanum brevidens</i> chromosomal addition/substitution lines
Authors: Dong F. , Tek A.L. , Frasca A.B.L. , McGrath J.M. , Wielgus S.M. , Helgeson J.P. , Jiang J. 
Published: March 2005

<i>Solanum brevidens</i> is a wild diploid potato species possessing high levels of resistances to several major potato diseases. We previously developed fertile somatic hybrids between <i>S. brevidens</i> and the cultivated potato <i>(Solanum tuberosum)</i> in order to introgress disease resistances from this wild species into potato. A series of backcross progenies was developed from a hexaploid somatic hybrid A206. Using a combination of <i>S. brevidens</i>-specific randomly amplified polymorphic DNA (RAPD) markers and a sequential genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) technique, we identified all 12 <i>S. brevidens</i> chromosomes in the backcross progenies. Seven potato-<i>S. brevidens</i> monosomic chromosome addition lines (chromosomes 1, 3, 4, 5, 8, 9 and 10) and one monosomic substitution line (chromosome 6) were identified, and the remaining four <i>S. brevidens</i> chromosomes (2, 7, 11, and 12) were included in two other lines. These chromosomal addition/substitution stocks provide valuable tools for potato cytogenetic research, and can be used to introgress disease resistances from <i>S. brevidens</i> into potato.
Cytogenetics of <i>Triticum</i> × <i>Dasypyrum</i> hybrids and derived lines
Authors: Minelli S. , Ceccarelli M. , Mariani M. , de Pace C. , Cionini P.G. 
Published: March 2005

Genomic in situ hybridization was used to study <i>Triticum × Dasypyrum</i> wide hybrids and derived lines. A cytogenetic investigation was carried out in progenies of (i) amphiploids derived from <i>T. turgidum</i> var. <i>durum</i> (<i>T. durum</i>; 2n = 14; genomes AABB) × <i>D. villosum</i> (2n = 14; genome VV), (ii) three-parental hybrids <i>(T. durum × D. villosum) × T. aestivum</i> (2n = 42, genomes A′A′B′B′D′D′), and (iii) <i>T. aestivum</i> aneuploid lines carrying <i>D. villosum</i> chromosomes or chromatin. The amphiploids derived from <i>T. durum × D. villosum</i> showed a stable chromosomal constitution, made up of 14 V chromosomes, 14 chromosomes carrying the wheat A genome and 14 chromosomes carrying the B genome. High karyological instability was observed in the progenies of three-parental hybrids <i>([T. durum × D. villosum] × T. aestivum)</i>. Plants having the expected 14 A chromosomes, 14 B chromosomes, 7 D chromosomes, and 7 V chromosomes were rather rare (4.5%). Many progeny plants (45.5%) had the hexaploid wheat genome with 42 chromosomes and lacked any detectable <i>D. villosum</i> chromatin. Other plants (50%) had 14 A chromosomes and 14 B chromosomes, plus variable numbers of D and V chromosomes, the former being better retained than the latter in most cases. Some <i>T. aestivum</i> lines carrying <i>D. villosum</i> chromosomes or chromatin, as the result of addition, substitution, or recombination events or even a combination of these karyological events, were found to be stable. Other lines were unstable, and these lines carried 1V, 3V, or 5V chromosomes or their portions. Substitution or recombination events where 1V chromosomes were involved could concern the homeologous counterparts in both the A and B and D genomes of wheat. No line could be recovered where the shorter arm of 3V chromosomes was present. Changes in the morphology and banding pattern of V chromosomes were observed in hybrids that did not carry the entire <i>D. villosum</i> complement. By comparing the results of our cytogenetic analyses with certain phenotypic characteristics of the lines studied, genes for discrete traits could be assigned to specific V chromosomes or V chromosome arms. From the frequency of V chromosomes that were involved in chromatin exchanges with or substituted for one of their homeologous counterparts in the A, B, and D wheat genomes, it was inferred that <i>D. villosum</i> belongs to the same phyletic lineage as <i>T. urartu</i> (donor of the A genome of wheat) and <i>Aegilops speltoides</i> (B genome), and that <i>Ae. squarrosa</i> (D genome) diverged earlier from <i>D. villosum.</i>
Influence of the Organic Matrix on Root Dentine Erosion by Citric Acid
Authors: Hara A.T. , Ando M. , Cury J.A. , Serra M.C. , González-Cabezas C. , Zero D.T. 
Published: March 2005

This investigation was conducted in an attempt to clarify the role of the organic matrix in bovine dentine demineralisation by 1% citric acid. Dentine slabs (n = 15) were treated for 2 min with 10% sodium hypochlorite (NaOCl, a strong protein solvent), 2% glutaraldehyde (GDA, a protein fixative) or deionised water (DIW, as negative control) prior to each of 5 demineralisation periods of 30 min. The mineral loss (ΔZ), lesion depth (LD) and surface loss (SL) were determined after each period of demineralisation, by transverse microradiography. The NaOCl-treated group showed higher ΔZ and LD than the GDA- and DIW-treated groups. No differences between GDA and DIW groups were found. The ΔZ and LD profiles were explained by quadratic fits (r<sup>2</sup> >0.80; p = 0.001) in all groups. SL was detected only in the NaOCl-treated group. The data suggested that the maintenance of the organic matrix in the lesion might be important to reduce the erosion progression rate.